A displacement detection device includes a light source, an image sensor and a processing unit. The light source is configured to illuminate a work surface. The image sensor is configured to capture reflected light from the work surface and to output an image frame. The processing unit is configured to select a window of interest in the image frame having a maximum image feature and to calculate a displacement of the displacement detection device according to the window of interest.

1. Field of the Disclosure
This disclosure generally relates to an interactive device and, more particularly, to a displacement detection device that may dynamically select pixels of interest in the image frame to accordingly calculate the displacement.
2. Description of the Related Art
The conventional optical mouse generally includes a light source, an image sensor and a processing unit and is configured to be operated by a user on a work surface. The light source is configured to illuminate the work surface. The image sensor is configured to receive reflected light from the work surface and to output image frames. The processing unit is configured to calculate a displacement of the optical mouse with respect to the work surface according to the image frames outputted by the image sensor, e.g. calculating the displacement according to the correlation between the image frames.
In the conventional optical mouse, the image sensor is configured to detect reflected light from the work surface. Therefore, when the image quality of the image frames captured by the image sensor is poor, it may not be able to calculate the displacement correctly.
For example referring to FIG. 1, an optical mouse generally includes a light source 81 configured to illuminate a work surface 9 through a lens 82, and the reflected light from the work surface 9 is received by an image sensor 84 through another lens 83. In assembling the optical mouse, the image sensor 84 may not be exactly disposed at an expected position. For example, if the image sensor is disposed at the position 84′ rather than at the position 84, the image quality of the image frames formed by capturing the reflected light of the work surface 9 by the image sensor may be poor and the poor images may lead to errors in calculation.
In addition, even though the image sensor 84 is exactly disposed at the expected position in assembling, the imaging may still have a position deviation when the optical mouse is operated on different work surfaces. For example referring to FIG. 2A, it shows a schematic diagram of the optical mouse operated on a surface of a glass in which reflected light of the work surface 9 still can be received by the image sensor 84. However, when the optical mouse is operated on a surface of another glass having a larger thickness as shown in FIG. 2B, the image sensor 84 may not able to receive the reflected light of the work surface 9 correctly such that the image quality is decreased and errors may occur in calculation.
Accordingly, the present disclosure further provides a displacement detection device that can be operated on different work surfaces and can effectively overcome the low image quality caused by the assembling error.


An architecture and method for permitting internet telephones assigned to a common telephone number but each having a unique IP address to be used in the manner of telephones and extension telephones in PSTN. A calling agent is provided with the fully defined address of two or more telephony devices. Telephone traffic to or from either of these devices is directed to a call agent, which contacts a gateway, which rings one or both of the telephony devices. This gateway then forms a bridge with a secondary gateway, to which are attached the other telephony devices that are to act as extensions of the first, and combines the audio from both so that they appear to the consumer to act like conventional PSTN extension telephones. This architecture can be used with any Internet Protocol telephony device, including video telephones.

For well over a century, telephone access has been provided by public switched telephone networks (PSTN, also known as "POTS"), in which each call requires the dedicated use of an individual telephone circuit. Improvements have been made to this system to make it more efficient (such as digitizing the analog signals that carry voice traffic), but still, the system requires the use of dedicated circuits, and thus is inherently limited in the uses to which its potential bandwidth may be put.
Conventional PSTN has also proven itself to be ill-suited to providing the consumer with certain telecommunication features believed to be desirable at an affordable price-point. For example, while video phones have been available to the public since the early 1960's, they have achieved only modest market penetration in the business market, and very little in the consumer market.
The development of Internet Protocol networks, which makes far more efficient use of available bandwidth by packetizing data streams into data frames and transporting them along dynamically changing routes, has opened up the possibility of providing the consumer both with conventional voice-only telephone services and video telephony at very competitive prices. Typically, these services can be provided over Internet Protocol networks via Voice-over Internet Protocol (VoIP), the increasingly widespread acceptance of which has facilitated the broad roll-out of IP telephony products and services to the consumer. However, the commercial acceptance of such services depends not only on their cost, but also on their being easy to use and familiar to the consumer.
One area in which PSTN is particularly easy to use is in the use of extension telephones. When a user wishes to switch phones or join in on a conversation using an extension telephone, all that he must do is raise the handset from the hook. The commercial acceptance of VoIP telephony can be advanced by systems that are similarly transparent and easy for the consumer to use.

Architecture for linking multiple internet protocol telephony devices having a common telephone number


A method (600) that adjusts, at a predetermined boundary of a protocol utilized in decoding information from a signal received by a receiver (122), a symbol rate of the protocol (400). A processor (208) loads into a programmable counter (306), before a first boundary (412) of the protocol (400), a count of clock cycles defined to be received in the signal between the first and predetermined boundaries (414). The counter (306) counts from the first boundary (412), for a number of clock cycles equal to the count, a recovered bit clock synchronized with the signal and having the bit rate of the signal, to detect an occurrence of the predetermined boundary (414). The processor (208) loads, between the first (412) and predetermined boundaries (414), the another symbol rate into a bit-rate selection circuit (304). An output symbol rate of the bit-rate selection circuit (304) is enabled upon detecting the occurrence of the predetermined boundary (414), thereby adjusting the output symbol rate to the other symbol rate at the predetermined boundary (414).

With the advent of multi-speed paging protocols such as FLEX.TM., REFLEX.TM., and InFLEXion.TM. it is essential for clock generator circuits, utilized by message decoding devices operating within these protocols, to maintain glitch-free clock synchronization with the protocol during transitions in protocol speeds.
Thus, what is needed is a method and apparatus in a communication receiver for adjusting an operating attribute at a predetermined boundary of a communication protocol. In particular, the method and apparatus must maintain synchronization with the communication protocol in an error free manner.

Method and apparatus in a communication receiver for adjusting an operating attribute at a predetermined boundary of a protocol


In a laser-diode-pumped laser apparatus, a solid-state laser crystal doped with at least one rare-earth element including at least Pr3+ is pumped with a laser diode, and emits laser light. In the first aspect, the laser diode has an active layer made of one of an InGaN, InGaNAs, and GaNAs materials, and an optical wavelength conversion element converts the solid-state laser light into ultraviolet laser light by wavelength conversion. In the second aspect, the solid-state laser crystal is codoped with Pr3+ and at least one of Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+. In the third aspect, instead of the solid-state laser crystal, an optical fiber codoped with Pr3+ and at least one of Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+ is pumped with a GaN-based compound laser diode. In the fourth aspect, an optical fiber codoped with Pr3+ and at least one of Er3+, Ho3+, Dy3+, Eu3+, Sm3, Pm3, and Nd3+ amplifies incident light having a wavelength which is identical with a wavelength of fluorescence generated by pumping of the optical fiber with a GaN-based compound laser diode.

1. Field of the Invention
The present invention relates to a laser-diode-pumped solid-state laser apparatus. The present invention also relates to a laser-diode-pumped fiber laser apparatus. The present invention further relates to a laser-diode-pumped fiber laser amplifier.
2. Description of the Related Art
(1) Ultraviolet Laser
Highly efficient, high output power ultraviolet lasers which continuously oscillate in the ultraviolet wavelength range are required, for example, for applications in ultraviolet lithography, fluorometric analysis of organic cells, and the like. GaN-based compound semiconductor lasers having an active layer made of an InGaN, InGaNAs, or GaNAs material are known as lasers which oscillate in the ultraviolet wavelength range. Recently, GaN-based compound semiconductor lasers which can continuously oscillate for a thousand hours at the wavelength of 400 nm with output power of several milliwatts are provided.
However, the current GaN-based compound semiconductor lasers cannot emit laser light with output power of 100 mW or more by a single transverse mode, which is required in many applications. In addition, the oscillation efficiency in the current GaN-based compound semiconductor lasers which emit laser light having wavelengths of 380 nm or below is low, and the lifetimes of such semiconductor lasers are very short.
On the other hand, wavelength-conversion solid-state lasers which output ultraviolet laser beams having wavelengths of 400 nm or below are known. In these wavelength-conversion solid-state lasers, wavelengths of laser oscillation light are shortened to the ultraviolet wavelengths by second harmonic generation (SHG) or third harmonic generation (THG) using nonlinear optical crystals.
However, solid-state laser mediums which can efficiently oscillate in the wavelength range of 700 to 800 nm have not yet been found. Therefore, it is difficult to obtain high output power from the wavelength-conversion solid-state lasers in which the wavelengths of the laser light are shortened by second harmonic generation (SHG).
In addition, the efficiency of the wavelength-conversion solid-state lasers in which the wavelengths of the laser light are shortened by third harmonic generation (THG) is essentially low, and the current THG wavelength-conversion solid-state lasers can oscillate in only a pulse mode. In order to realize continuous oscillation, it is necessary to maintain resonance of SHG light of the fundamental wave, and highly accurate temperature adjustment of a resonator with a precision of 0.01iC is required for oscillation of the THG light. However, such accurate temperature adjustment is practically difficult in terms of cost.
(2) Blue and Green Lasers
Gas-laser-pumped solid-state laser apparatuses in which a Pr3+-doped solid-state laser crystal is pumped with a gas laser such as an Ar laser are known as disclosed in Journal of Applied Physics, vol. 48, No. 2, pp.650-653 (1977), and Applied Physics, B58, pp.149-151 (1994). In addition, a solid-state laser apparatus in which a Pr3+-doped solid-state laser crystal is pumped by second harmonic (SH) light from a lamp-pumped solid-state laser is known, as disclosed in xe2x80x9cAdvanced Solid-State Laser,xe2x80x9d OSA TOPS, vol.19, pp.34-35, the Optical Society of America, 1998. In these solid-state laser apparatuses, it is possible to generate a laser beam in a blue wavelength range of 470 to 490 nm by a transition from 3P0 to 3H4. It is also possible to generate a laser beam in a green wavelength range of 520 to 550 nm by a transition from 3P1 to 3H1. Therefore, the above solid-state laser apparatuses can be used as a light source for recording a color image in a color sensitive material.
The light sources for use in recording a color image in a color sensitive material are required to be small in size, light in weight, and inexpensive. However, the above gas-laser-pumped and lamp-pumped solid-state laser apparatuses using the Pr3+-doped solid-state laser crystals are not suitable for use in recording a color image in a color sensitive material since the pumping light sources in these solid-state laser apparatuses are large, heavy, and expensive.
In addition, a solid-state laser apparatus in which a Pr3+-doped solid-state laser crystal is pumped by a blue laser beam emitted from an SHG laser apparatus is known as disclosed by Andy Clarkson, xe2x80x9cVisible and UV Sources,xe2x80x9d Technical Digest of CLEO ""99, University of Southampton, 1999.
However, the above SHG-pumped solid-state laser apparatuses using the Pr3+-doped solid-state laser crystals are also not suitable for use in recording a color image in a color sensitive material since the pumping light sources in the SHG-pumped solid-state lasers are large, heavy, and expensive.
As another solid-state laser apparatus which emits a laser beam having a wavelength in the blue or green wavelength range, Japanese Unexamined Patent Publication No. 4(1992)-318988 discloses a laser-diode-pumped SHG laser apparatus in which a solid-state laser beam is converted into a second harmonic, i.e., the wavelength of the solid-state laser beam is reduced by half by arranging a nonlinear optical crystal in a resonator.
However, the efficiency of wavelength conversion in the current laser-diode-pumped SHG laser apparatuses in which a wavelength of a solid-state laser beam is reduced by using a nonlinear optical crystal is not sufficiently high, and therefore it is difficult to obtain high output power. In addition, in such laser-diode-pumped SHG laser apparatuses, an etalon or the like is inserted for limiting the oscillation mode to a single mode. Therefore, loss in the resonator is great, and thus achievement of high output power becomes more difficult. Further, in order to match phases in the wavelength conversion, highly accurate temperature control is required, and therefore the outputs of the laser-diode-pumped SHG laser apparatuses are not stable. Moreover, since the numbers of parts are increased by the provision of the nonlinear optical crystal and the etalon, the laser-diode-pumped SHG laser apparatuses are expensive.
Recently, InGaN-based compound laser diodes and ZnMgSSe-based compound laser diodes which emit laser beams in the blue and green wavelength ranges have been developed.
Since, the oscillation wavelengths of the InGaN-based compound laser diodes increase with increase in the indium content, theoretically it is possible to obtain laser beams in the blue wavelength range of 470 to 490 nm, or laser beams in the green wavelength range of 520 to 550 nm. However, since the quality of the crystal deteriorates with the increase in the indium content, it is practically impossible to sufficiently increase the indium content, and the upper limit of the lengthened wavelength is about 450 nm.
In addition, blue light can be obtained by laser diodes having an active layer made of an InGaNAs or GaNAs material. The oscillation wavelengths in these laser diodes can also be increased by doping the active layer with arsenic. However, since the quality of the crystal deteriorates with the increase in the arsenic content, the upper limit of the wavelength realizing high output power is about 450 to 460 nm.
Further, the current ZnMgSSe-based compound laser diodes cannot oscillate continuously at wavelengths below 500 nm at room temperature, and the lifetimes are at most a hundred hours.
Japanese Unexamined Patent Publication No. 11(1999)-17266, which is assigned to the present assignee, discloses a laser-diode-pumped solid-state laser apparatus which is inexpensive, and can emit a laser beam in the blue or green wavelength range with high efficiency, high output power, and high output stability. In this laser-diode-pumped solid-state laser apparatus, a Pr3+-doped solid-state laser crystal is pumped with an InGaN-based compound laser diode having an active layer made of an InGaN-based compound, or an InGaNAs-based compound laser diode having an active layer made of an InGaNAs-based compound, or a GaNAs-based compound laser diode having an active layer made of a GaNAs-based compound. However, in the above laser-diode-pumped solid-state laser apparatus, the amount of the pumping light absorbed by the Pr3+-doped solid-state laser crystal is not sufficient.
(3) Fiber Lasers
As disclosed in the Technical Report of the Institute of Electronics, information and Communication Engineers in Japan, LQE95-30 (1995) p.30, and Optics Communications 86 (1991) p.337, laser-diode-pumped fiber laser apparatuses in which an optical fiber having a core made of a Pr3+-doped fluoride is pumped with a laser diode so as to generate a laser beam are known.
In addition, the above references also disclose an optical fiber amplifier in which an optical fiber having a Pr3+-doped core is pumped with a laser diode so as to generate fluorescent light, and incident light of the optical fiber is amplified by the energy of the fluorescent light when the wavelength of the incident light is included in the wavelength range of the fluorescent light.
Besides, an Ar-laser-pumped, Pr3+-doped fiber laser apparatus is also disclosed in Optics Communications 86 (1991) p.337, which reports laser oscillations at the wavelengths of 491, 520, 605, and 635 nm with pumping light having a wavelength of 476.5 nm.
Further, Japanese Patent Application No. 9(1997)-110554, which is assigned to the present assignee, discloses a laser-diode-pumped solid-state laser apparatus in which a Pr3+-doped solid-state laser crystal is pumped with a laser diode.
The above laser-diode-pumped fiber laser apparatuses, Ar-laser-pumped, Pr3+-doped fiber laser apparatus, and laser-diode-pumped solid-state laser apparatus can emit blue or green laser beams, and the above optical fiber amplifier can amplify blue or green laser beams. In this respect, it is considered that these apparatuses may be used as constituents of light sources for recording a color image in a color sensitive material.
However, a water cooling system is required for operating the Ar-laser-pumped, Pr3+-doped fiber laser apparatus with high power of a few watts to several tens of watts. Therefore, the size is increased, and the lifetime and the efficiency are reduced.
On the other hand, since the laser-diode-pumped solid-state laser apparatuses in which a Pr3+-doped solid-state laser crystal is pumped with a laser diode has such structure that thermal energy of pumping light is concentrated in a small solid-state laser crystal, absorption of the thermal energy by the crystal causes heat generation and a thermal lens effect. Therefore, beam quality and output stability deteriorate. In particular, the deterioration is serious in the operation with high power of a few watts to several tens of watts.
Japanese Unexamined Patent Publication No. 11(1999)-204862, which is assigned to the present assignee, discloses a fiber laser apparatus which can be realized in a small size, and can emit a blue or green laser beam with high efficiency, high output power, and highly stable quality and output level. In this fiber laser apparatus, an optical fiber having a Pr3+-doped core is pumped with a GaNAs-based compound laser diode.
In addition, JPP No. 11-204862 also discloses a fiber laser amplifier which can be realized in a small size, and can amplify a blue or green laser beam with high efficiency and highly stable quality and output level. In this fiber laser amplifier, a first optical fiber having a Pr3+-doped core is pumped with a GaNAs-based compound laser diode so as to generate fluorescent light, and incident light of the optical fiber is amplified by the energy of the fluorescent light when the wavelength of the incident light is included in the wavelength range of the fluorescent light.
However, in the above fiber laser apparatus and fiber laser amplifier disclosed in JPP No. 11-204862, the amount of the pumping light absorbed by the fiber core is insufficient.
An object of the present invention is to provide a semiconductor-laser-pumped solid-state laser apparatus, which can continuously emit ultraviolet laser light having the wavelengths of about 360 nm or below with high efficiency and high output power, and can be produced at low cost.
Another object of the present invention is to provide a laser-diode-pumped solid-state laser apparatus, in which a solid-state laser crystal is pumped with a laser diode having an active layer made of an InGaN, InGaNAs, or GaNAs material, an amount of pumping light absorbed by the solid-state laser crystal is increased, and high efficiency and high output power are achieved.
Still another object of the present invention is to provide a fiber laser apparatus, in which a solid-state laser crystal is pumped with a GaN-based compound laser diode, an amount of pumping light absorbed by a fiber core is increased, and high efficiency and high output power are achieved.
A further object of the present invention is to provide a fiber laser amplifier, in which a solid-state laser crystal is pumped with a GaN-based compound laser diode, an amount of pumping light absorbed by a fiber core is increased, and a high amplifier gain is achieved.
(1) According to the first aspect of the present invention, there is provided a laser-diode-pumped solid-state laser apparatus including a laser diode which has an active layer made of one of an InGaN, InGaNAs, and GaNAs materials, and emits a pumping laser beam; a solid-state laser crystal which is doped with at least one rare-earth element including at least Pr3+, and emits solid-state laser light when the solid-state laser crystal is pumped by the pumping laser beam; and an optical wavelength conversion element which converts the solid-state laser light into ultraviolet laser light by wavelength conversion.
Preferably, the laser-diode-pumped solid-state laser apparatus according to the first aspect of the present invention may also have one or any possible combination of the following additional features (i) to (iii).
(i) The solid-state laser crystal may be codoped with Pr3+ and at least one of Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+.
(ii) The solid-state laser crystal may emit a solid-state laser beam having a wavelength of about 720 nm by a transition from 3P0 to 3F4 in the solid-state laser crystal, and the ultraviolet light may be a second harmonic of the solid-state laser light, and have a wavelength of about 360 nm.
(iii) The optical wavelength conversion element may be made of a nonlinear optical crystal having periodic domain-inverted structure.
When a Pr3+-doped solid-state laser crystal such as a Pr3+:YLF crystal is pumped with a GaN-based compound laser diode, the Pr3+-doped solid-state laser crystal efficiently oscillates in the wavelength range of 700 to 800 nm. For example, the Pr3+-doped solid-state laser crystal efficiently emits a solid-state laser beam having the wavelength of 720 nm by a transition from 3 to 3F4, where the wavelength of 720 nm corresponds to an oscillation peak of Pr3+ in the infrared range. In this case, high intensity ultraviolet light having the wavelength of 360 nm is obtained by wavelength conversion of the solid-state laser beam having the wavelength of 720 nm into a second harmonic by using an optical wavelength conversion element.
In addition, it is relatively easy for the GaN-based compound laser diodes to emit laser beams in the wavelength range of 380 to 430 nm, and each of the dopants, Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+, has an absorption band in the wavelength range of 380 to 430 nm. Therefore, these dopants can be pumped with the GaN-based compound laser diodes. In the solid-state laser crystal codoped with Pr3+ and at least one of Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+, the excited electrons can move to an excitation level (e.g., 3P0 to 3P1) of Pr3+. Then, the solid-state laser crystal can emit a solid-state laser beam corresponding to an oscillation peak of Pr3+, i.e., corresponding to a transition between two energy levels of Pr3+. For example, the solid-state laser crystal can emit a solid-state laser beam having the wavelength of 720 nm by a transition from 3P0 to 3F4, or the like. In this case, high intensity ultraviolet light having the wavelength of 360 nm can be obtained by wavelength conversion of the solid-state laser beam having the wavelength of 720 nm into a second harmonic by using an optical wavelength conversion element.
As mentioned above, it is relatively easy for the GaN-based compound laser diodes to emit laser beams in the wavelength range of 380 to 430 nm. In particular, in the wavelength range of 400 to 410 nm, the output power of the currently available GaN-based compound laser diode is maximized. Therefore, since Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+ are pumped with the GaN-based compound laser diodes, the absorbed amount of the pumping light is increased, and thus high efficiency and high output power can be achieved.
In particular, when the optical wavelength conversion element performs wavelength conversion into a second harmonic, the construction for performing the wavelength conversion can be simplified, compared with the construction of wavelength conversion into a third harmonic, and therefore a laser-diode-pumped solid-state laser apparatus can be realized at low cost.
In addition, the thermoconductivity of the GaN-based compound laser diodes is very great (i.e., about 130 W/mxc2x0 C.), compared with the thermoconductivity of the other laser diodes such as ZnMgSSe-based compound laser diodes (which have thermoconductivity of 4 W/mxc2x0 C.). Further, since the dislocation mobility of the GaN-based compound laser diodes is very low, compared with that of ZnMgSSe-based compound laser diodes, the COD (catastrophic optical damage) thresholds of the GaN-based compound laser diodes are very high. Therefore, it is easy to achieve a long lifetime and high output power. Since the laser-diode-pumped solid-state laser apparatus according to the first aspect of the present invention uses a GaN-based compound laser diode as a pumping light source, the laser-diode-pumped solid-state laser apparatus can also have a long lifetime, and emit an ultraviolet laser beam with high output power.
(2) According to the second aspect of the present invention, there is provided a laser-diode-pumped solid-state laser apparatus including a laser diode which has an active layer made of one of an InGaN, InGaNAs, and GaNAs materials, and emits a pumping laser beam; and a solid-state laser crystal which is codoped with Pr3+ and at least one of Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+, and emits solid-state laser light when the solid-state laser crystal is pumped by the pumping laser beam.
Preferably, the laser-diode-pumped solid-state laser apparatus according to the second aspect of the present invention may also have one or any possible combination of the following additional features (iv) to (vi)(iv)
The solid-state laser light may have a blue wavelength in a range of 465 to 495 nm.
(v) The solid-state laser light may have a green wavelength in a range of 515 to 555 nm.
(vi) The solid-state laser light may have a red wavelength in a range of 600 to 660 nm.
Since each of the dopants, Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+, has an absorption band in the wavelength range of 380 to 430 nm, these dopants can be pumped with the GaN-based compound laser diodes. Therefore, in the solid-state laser crystal codoped with Pr3+ and at least one of Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+, the excited electrons can move to excitation levels (e.g., 3P0 to 3P1) of Pr3+, and the solid-state laser crystal can emit blue, green, and red laser beams corresponding to oscillation peaks of Pr3+ by transitions between the energy levels of Pr3+.
As mentioned before, it is relatively easy for the GaN-based compound laser diodes to emit laser beams in the wavelength range of 380 to 430 nm. In particular, in the wavelength range of 400 to 410 nm, the output power of the currently available GaN-based compound laser diodes is maximized. Therefore, since Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+ are pumped with the GaN-based compound laser diodes, the absorbed amount of the pumping light is increased, and thus high efficiency and high output power can be achieved.
In addition, for the same reasons as explained for the first aspect of the present invention, the laser-diode-pumped solid-state laser apparatus according to the second aspect of the present invention can have a long lifetime, and emit a laser beam in the blue and green wavelength ranges with high output power.
The GaN-based compound laser diodes used as a pumping light source may be a single longitudinal or transverse mode, broad-area, phased-array, or MOPA (master oscillator power amplifier) type high power laser diode. In addition, one or more GaN-based compound laser diodes may be used in a laser-diode-pumped solid-state laser apparatus. Thus, the laser-diode-pumped solid-state laser apparatus according to the second aspect of the present invention can emit a laser beam with an even higher output power, e.g., in the order of 1 W.
In addition, since the laser-diode-pumped solid-state laser apparatus according to the second aspect of the present invention does not require a nonlinear optical crystal, an etalon or the like, the number of constituents of the laser-diode-pumped solid-state laser apparatus is small, i.e., the construction of the laser-diode-pumped solid-state laser apparatus can be simplified, and the operation is stable in a wide temperature range. Therefore, the laser-diode-pumped solid-state laser apparatus according to the second aspect of the present invention can be used as a stable and inexpensive pumping light source.
Further, since the laser-diode-pumped solid-state laser apparatus according to the second aspect of the present invention does not perform wavelength conversion, highly accurate temperature control for phase matching is unnecessary. Therefore, it is possible to avoid the output instability due to the temperature control, i.e., high output stability can be achieved. (3) According to the third aspect of the present invention, there is provided a fiber laser apparatus including a GaN-based compound laser diode which emits a pumping laser beam; and an optical fiber which is codoped with Pr3+ and at least one of Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+, and emits laser light when the optical fiber is pumped by the pumping laser beam.
Preferably, the fiber laser apparatus according to the third aspect of the present invention may also have one or any possible combination of the following additional features (vii) to (x).
(vii) The laser light may have a blue wavelength in a range of 465 to 495 nm.
(viii) The laser light may have a green wavelength in a range of 515 to 555 nm.
(ix) The laser light may have a red wavelength in a range of 600 to 660 nm.
(x) The GaN-based compound laser diode may have an active layer made of one of an InGaN, InGaNAs, and GaNAs materials.
The fiber laser apparatus according to the third aspect of the present invention has basically the same advantages as the laser-diode-pumped solid-state laser apparatus according to the second aspect of the present invention.
(4) According to the fourth aspect of the present invention, there is provided a fiber laser amplifier including a GaN-based compound laser diode which emits a pumping laser beam; and an optical fiber which is codoped with Pr3+ and at least one of Er3+, Ho3+, Dy3+, Eu3+, Sm3+, Pm3+, and Nd3+, generates fluorescence with at least one wavelength when the optical fiber is pumped by the pumping laser beam, and amplifies incident light which has a wavelength included in the at least one wavelength of the fluorescence.
Preferably, the fiber laser amplifier according to the fourth aspect of the present invention may also have one or any possible combination of the following additional features (xi) to (xiv).
(xi) The fluorescence may have a blue wavelength in a range of 465 to 495 nm.
(xii) The fluorescence may have a green wavelength in a range of 515 to 555 nm.
(xiii) The fluorescence may have a red wavelength in a range of 600 to 660 nm.
(xiv) The GaN-based compound laser diode may have an active layer made of one of an InGaN, InGaNAs, and GaNAs materials.
The fiber laser amplifier according to the fourth aspect of the present invention has basically the same advantages as laser-diode-pumped solid-state laser apparatus according to the second aspect of the present invention.

Laser-diode-pumped laser apparatus in which Pr3+-doped laser medium is pumped with GaN-based compound laser diode


A sound source separating device includes: a sound collecting unit configured to collect sound signals using a plurality of microphones; a sound source localizing unit configured to localize a sound source on the basis of the sound signals collected by the sound collecting unit; a sound source separating unit configured to separate the sound signals collected by the sound collecting unit into sound sources corresponding to the number of fixed sound sources and fixed sound source directions without using the sound source localization result from the sound source localizing unit; and a speech extracting unit configured to extract speech signals of the fixed sound sources on the basis of the sound source localization result from the sound source localizing unit and the sound source separation result from the sound source separating unit.

Field of the Invention
The present invention relates to a sound source separating device and a sound source separating method.
Description of Related Art
In a vehicle, a speech recognition system for operating a navigation system or the like with a voice command has been proposed. In such a speech recognition system, for example, when a vehicle travels on an expressway or when music is played in a vehicle, a speech recognition rate is likely to decrease due to mixture of large noise from the surroundings.
Accordingly, in the speech recognition system, a sound source position of speech of a speaker sitting in a seat is stored as preset information in advance for each seat position. In the speech recognition system, a process of retrieving the preset information on the basis of the seat position detected by a sensor, separating the speech of the speaker with reference to the retrieved preset information, and recognizing the speech has been proposed (for example, see Republished Japanese Translation No. WO2006/025106 of the PCT international Publication for Patent Application).
A sound source separating device according to the related art that separates sound sources will be described below in brief.
FIG. 14 is a block diagram illustrating a schematic configuration of a sound source separating device 900 according to the related art. As illustrated in FIG. 14, the sound source separating device 900 according to the related art includes a sound collecting unit 911, a sound signal acquiring unit 912, a sound source localizing unit 913, and a sound source separating unit 914.
The sound collecting unit 911 is a microphone array including N (where N is an integer equal to or greater than 2) microphones. The sound collecting unit 911 collects sound signals and outputs the N collected sound signals to the sound signal acquiring unit 912.
The sound signal acquiring unit 912 acquires the N sound signals output from the N microphones of the sound collecting unit 911 and outputs the N acquired sound signals to the sound source localizing unit 913 and the sound source separating unit 914. The sound source localizing unit 913 estimates a direction of a sound source (which is also referred to as sound source localization) from the N sound signals output from the sound signal acquiring unit 912, for example, using a multiple signal classification (MUSIC) method and outputs information indicating the estimated direction of a sound source to the sound source separating unit 914. The number of sound sources which are localized by the sound source localizing unit 913 dynamically varies depending on an environment in which the sound source separating device 900 is used.
The sound source separating unit 914 separates the sound source on the basis of the information indicating the direction of the sound source which is output from the sound source localizing unit 913 in response to the sound signals output from the sound signal acquiring unit 912, for example, using a geometrically constrained high-order decorrelation-based source separation with adaptive step-size control (GHDSS-AS) method which is a hybrid of blind source separation and beam forming. In the GHDSS-AS method, a separation signal is estimated from the collected sound signals using a separation matrix. When a sound source is separated using the separation matrix W in this way, it is known that stability of the separation matrix affects sound source separation performance. The sound source separating unit 914 updates the separation matrix only when a direction of a sound source is detected by the sound source localizing unit 913.

Sound source separating device and sound source separating method


A positive electrode active material, which gives a non-aqueous electrolyte secondary battery capable of high input/output where resistance due to a battery reaction in a low temperature environment is suppressed, is produced by a method comprising: (a)providing a nickel hydroxide which is represented by the general formula Ni1−(x+y)CoxMy(OH)2, (b)heating the nickel hydroxide at a temperature not lower than 600° C. and not higher than 1000° C. to produce a nickel oxide which is represented by the general formula Ni1−(x+y)CoxMyO; and (c)mixing the nickel oxide and a lithium compound to obtain a mixture and heating the mixture at a temperature not lower than 700° C. and not higher than 850° C. to produce a lithium-containing composite oxide which is represented by the general formula LiNi1−(x+y)CoxMyO2, where 0.1≦x≦0.35 and 0.03≦y≦0.2 are satisfied and M is at least one selected from the group consisting of Al, Ti and Sn.

In recent years, as having a high operation voltage and high energy density, non-aqueous electrolyte secondary batteries, especially lithium-ion secondary batteries, have come into practical use as power sources for driving portable electronic instruments such as cell phones, laptop computers, video camcoders, and have made rapid progress. Lithium-ion secondary batteries are becoming the mainstream of small-sized secondary batteries and the production volume thereof is on the increase.
Lithium-ion secondary batteries are not only for small-sized customer applications, but the technical development thereof into large-sized batteries having a large capacity for power storage, electric vehicles and the like has been accelerated, and in particular, lithium-ion secondary batteries for hybrid electric vehicles (HEVs) are under rapid development. Furthermore, in the area of power-sources for driving electric tools and the like, required to have very high output power, high-output type lithium-ion secondary batteries as replacements of conventional nickel-cadmium batteries and nickel-metal hydride batteries are under rapid development.
Herein, the aforesaid high-output type lithium-ion secondary batteries largely differ in applications and required performance from lithium-ion secondary batteries for small-sized customer applications. In the case of lithium-ion secondary batteries for HEVs, for example, an engine of an HEV needs power-assisting and regenerating within a fraction of a second with a limited capacity of the battery, necessitating considerably high input/output power of the battery. It is therefore necessary to give preference to a high input/output characteristic over the other battery characteristics, and to make the internal resistance of the battery as small as possible.
Consequently, in addition to development and selection of active materials and electrolytes, there have been attempted reconsideration of current collecting structures of electrodes, reduction in resistance of battery constituents, an increase in electrode reaction area by making the electrode thinner and longer, and the like.
As for positive electrode active materials of the lithium-ion secondary batteries for HEVs, LiNiMO2 type active materials have been considered as most suitable—and the development thereof has been advanced (e.g. Japanese Laid-Open Patent Publication No. Hei 5-242891, Japanese Laid-Open Patent Publication No. Hei 9-231973, Japanese Laid-Open Patent Publication No. Hei 9-293497, and Japanese Laid-Open Patent Publication No. Hei 9-237631). There have further been conducted studies on production methods of the LiNiMO2 type active materials (e.g. Japanese Laid-Open Patent Publication No. Hei 10-27611, Japanese Laid-Open Patent Publication No. Hei 11-60244, and Japanese Laid-Open Patent Publication No. Hei 11-219706).
As thus described, the lithium-ion secondary battery required to have high input/output power needs to sustain large current pulse charge or discharge from about 50% state of charge. It is thereby necessary to make the internal resistance of the battery as small as possible.
The internal resistance of the battery here is comprised of: a resistance element due to battery constituents, an electrolyte and the like; and a resistance element due to a battery reaction. The internal resistance of the battery occurring within the temperature range of a normal temperature to a high temperature can be reduced by reducing the former resistance element, thereby enabling the battery to have high input/output power. In the case of the internal resistance of the battery occurring within the low temperature range of 0° C. and below, however, the latter resistance element due to a battery reaction contributes far more than the former resistance element, making it difficult for the battery to have high input/output power without reduction in the latter resistance element.
Some of the aforesaid conventional LiNiMO2 type active materials are produced by mixing nickel hydroxide, a compound containing the element M to be incorporated in the nickel hydroxide, and a lithium compound such as lithium hydroxide, and heating the mixture. Further, some of the aforesaid LiNiMO2 type active materials are produced by preparing NiM(OH)2, incorporated with M by a coprecipitation method, mixing prepared NiM(OH)2 with a lithium compound, and then heating the mixture. The LiNiMO2 active materials thus obtained are somewhat different in performance, depending on the kind of M, composition and the like, but not largely different in physical properties, and it is therefore difficult to suppress the aforesaid increase in resistance due to a battery reaction in a low temperature environment. For example, when conductivity of an electrolyte excessively decreases at a low temperature, the ability of the active material to absorb and desorb lithium significantly deteriorates, leading to an unsatisfactory high input/output characteristic of the battery.

Production method of positive electrode active material for non-aqueous electrolyte secondary battery and positive electrode active material

Matsushita Electric Industrial Co., Ltd.


An active matrix substrate includes a photoelectric conversion element in a pixel P defined by a gate line and a data line. The photoelectric conversion element is connected with a bias line, and the bias line is connected with a bias terminal that supplies a bias voltage to the bias line. The bias terminal is connected with a first protection circuit that is formed with a nonlinear element. The first protection circuit is connected in a reverse-biased state between a first line to which a predetermined voltage higher than the bias voltage is supplied, and the bias terminal.

An active matrix substrate that includes a protection circuit for protecting driving elements such as switching elements from static electricity has been conventionally known. JP-A-2009-260305 discloses a photo IC that includes a light receiving element, an integrated circuit including a plurality of transistors, and a protection diode. As a protection diode, a photodiode is used, and each of the light receiving element and the integrated circuit is connected with one or a plurality of protection diodes. Each protection diode is provided in series or in parallel between the light receiving element and/or the integrated circuit, and a terminal. In this photo IC, the use of the photodiode as a protection diode allows a greater p-n junction surface than that of a transistor to be ensured, thereby making it possible to prevent electric field concentration due to surge current that would lead to dielectric breakdown of the protection diode.
In the above-described photo IC, however, since a cathode of each protection diode is connected with a light receiving element, if a greater surge current runs in a forward-bias direction of the protection diode, the surge current will cause electric current to flow from the cathode of the protection diode into the light receiving element, which could possibly break the light receiving element.

Active matrix substrate, and x-ray imaging panel


A combination burner for selectively firing oil, natural gas and liquid propane. A modular first section has primary and secondary air tubes coaxially arranged therein and communicates with the main combustion air supply fan. A modular section is joined by bolts or the like to the first section and into which the primary and secondary air tubes extend. A center air spin vane rack is upstream of the secondary air tube in the first section. An adjustable spin vane rack is located radially outwardly of the secondary air tube for selectively spinning the main combustion air for flame adjustability. An air diverter is provided at a downstream end of the primary air tube. A compressed air atomizer is also at the downstream end of the primary air tube.

The present invention relates to a lower cost, higher efficiency combination burner which fires on natural gas, fuel oil and liquid propane gas with lower CO emissions and high flame stability.
Conventional combination burners such as shown, for example, in U.S. Pat. Nos. 5,259,755 and 5,700,143, assigned to the assignee of the present application, experience one or more of the following conditions:
(1) high CO and unburned hydrocarbon emission;
(2) inadequate flame shaping to match the size of the available combustion space;
(3) low efficiency;
(4) flame instability oil when using compressed air atomization;
(5) bulky burners package size.
These shortcomings have long been known in the combustion industry but efforts by various sources to overcome them in one burner have been unsuccessful. For example, the xe2x80x9cECOSTARxe2x80x9d burner made by the Hauck Manufacturing Company, said assignee, achieved natural gas stability with an enlarged flame holding area but did not achieve other desired goals.
An object of the present invention has been to solve the problems and shortcomings encountered in conventional combination burners.
This object has been achieved by providing a combination burner of the general type shown in the above-referenced U.S. patents, whose disclosure is incorporated by reference herein, but in which a compact burner unit is configured with an adjustable and highly efficient spin section in the burner nose so as to provide substantially improved flame adjustability.
According to another aspect of the present invention, higher static air pressures are used to promote faster air/fuel mixing in natural gas, propane and oil so as to achieve higher flame intensities and thereby smaller flame volumes.
A still further aspect of the present invention involves achieving flame stability by enlarging the flame stabilization zone when the burner is on natural gas, ahd using an atomizer and diverting air ring on the primary air tube when the burner is on oil.
More specifically, the combination burner according to the present invention achieves these advantages by being provided, inter alia, with an adjustable and energy-efficient main air spin section located in the burner nose where it has been found to be most effective; a fixed secondary air spin section in the center; a higher pressure main air supply, via main air fan, to promote high exit velocities and fast mixing for higher combustion intensity; an air diverting ring to promote flame stability and eliminate overspray on oil firing; an enlarged gas stability point for improved flame stability on natural gas; a compressed air atomizer for oil firing; and a multiple propane nozzle for firing liquid propane.
The foregoing compact combustion burner provides lower CO emissions than in conventional burners, improves flame stability on natural gas, oil and propane, achieves faster mixing to improve combustion intensity, provides better flame shaping and adjustability and allows the use of modular manufacturing techniques.

Compact combination burner with adjustable spin section


A flat board has a top side and a distal and proximal end. Mounted on the flat board top side at the distal end is a target area defined by a goal element. Mounted on the flat board top side at the proximal end is a launching mechanism. A base member of the launching mechanism has first and second channels formed therein. The second channel receives a handle portion of a launch spoon. The first channel receives a first end of a string. A second end of the string attaches to a projectile. A spoon portion is provided with the launch spoon for holding the projectile therewithin. The game is played by first bending the launch spoon in a direction opposed from that of the goal element and thereafter releasing the launch spoon so that the projectile is propelled toward the goal element in hopes of having the projectile cross through the target area.

1. Field of the Invention
This invention relates to a game of skill. More particularly, it relates to a game of skill played on a small board, wherein the board resembles the professional game of football, baseball or basketball.
2. Description of Prior Art
In the prior art, games of skill are known. However, Applicant is unaware of any such game including all of the features and aspects of the present invention. The following prior art is known to Applicant:
U.S. Pat. No. 1,922,904 to Warren PA1 U.S. Pat. No. 2,722,211 to Eisele PA1 U.S. Pat. No. 2,828,964 to Horton PA1 U.S. Pat. No. 3,888,485 to Conti PA1 U.S. Pat. No. 4,550,911 to Daley
The present invention distinguishes from the teachings of these patents, taken alone or in combination with one another, as contemplating a novelty game of skill resembling one of many popular professional sports--namely, football, baseball and basketball--wherein a miniature field or court is provided having a goal at one end and a launching mechanism at the opposed end whereby a user launches a ball like element at the goal to score points.

Sport board game and method of playing same


A head shield device having a frame and a replaceable lens. An engagement axle having an large dimension and a small dimension is attached to the frame. The lens defines an aperture with a neck and an enlarged inner body. The small dimension of the axle is adapted to pass through the neck and rotation of the axle to the large dimension locks the lens in place on the frame. The axle rotation is controlled by a control device located on a tab assembly forming the engagement axle.

1. Field of the Invention
This invention relates to a shield apparatus to be worn by an individual to protect his forehead, eyes, nose, mouth, ears and the top of his head from projectiles thrown or shot at the wearer. More particularly, it relates to a shield apparatus of the described type which is molded of a plastic material, is light-weight and inexpensive in comparison to helmet-type protective head gear which primarily protects only the head and not the face. The shield device is designed to include a removable eye shield. The eye shield can easily be removed to allow a user to exchange eye shields or to clean the eye shield. An eye shield can then be inserted into the shield device. The shield device is designed so that the eye shield can not be removed while the shield device is in use on the wearer.
2. Description of the Known Art
Protective head gear or helmets are worn for safety reasons by many individuals on their jobs and in playing many sports. In particular, most construction workers are required to wear "hard hats," one example of the many different types of protective head gear. In some instances workers wear both a hard hat and safety goggles to protect their heads and eyes from injury. In sports, football for example, the players wear football helmets to protect their heads. The same is true with hockey players. They generally wear face masks. These head gears and/or face masks generally protect either the head or face, but not both. Furthermore, they do not protect both the face and head from objects thrown or shot at the wearer. Recently, paint ball, another sport, has increased in popularity. During this game the players shoot paint pellets at one another. These paint pellets travel at a relatively high velocity, and if a player is hit in the face by one of them, serious injury can result. Helmets designed to protect the head from injury will not protect the face in such cases, and those designed to protect the face do not protect the head.
Details of different types of masks are outlined in U.S. Pat. No. 6,886,183 issued to DeHaan et al. on May 3, 2005; U.S. Pat. No. 6,467,098 issued to Lee on Oct. 22, 2002; U.S. Pat. No. 6,381,749 issued to Cyr on May 7, 2002; U.S. Pat. No. 6,047,410 issued to Dondero on Apr. 11, 2000; U.S. Pat. No. 5,809,580 issued to Arnette on Sep. 22, 1998; U.S. Pat. No. 5,689,834 issued to Wilson on Nov. 25, 1997; U.S. Pat. No. 5,444,876 issued to Cooper et al. on Aug. 29, 1995; U.S. Pat. No. 5,148,550 issued to Hodgkinson et al. on Sep. 22, 1992; and U.S. Pat. No. 4,748,697 issued to Hodnett on Jun. 7, 1988. Each of these patents is hereby expressly incorporated by reference in their entirety. Several of these patents describe different areas of the various arts as noted by the following comments.
U.S. Pat. No. 6,886,183 issued to DeHaan et al. on May 3, 2005 discusses a goggle frame and lens assembly in which a secure assembly and disassembly is provided by the tab retention system including a plurality of tabs and mating tab retention holes, a central stability tab and a flush fit between the tabs and the goggle frame when the lens is secured within the front gutter of the frame.
U.S. Pat. No. 6,467,098 issued to Lee on Oct. 22, 2002 discusses goggles with removable lenses comprising a pair of soft lens rim each with a lens and a cushion in sucker format is formed with the soft lens rim into one body. Two soft lens rims are tied together with a bridge, the soft lens rims and the bridge are formed into one body with soft plastic. A groove in stair shape for the fixing ring and a hole for the fixing mechanism are inside the soft lens rim for a lens.
U.S. Pat. No. 6,381,749 issued to Cyr on May 7, 2002 discusses a protective mask adapted to be worn by persons engaging in physical games comprises a body consisting of a lens receiving portion. The lens receiving portion displays an opening which is covered by a removable flexible transparent lens having its opposite extremities configured with engagement portions that mount the lens to the body. A pair of anchor clamps is inserted at each opposite end of the lens to further secure the engagement of the lens to the mask body. The lens receiving portion defines an opening and includes first engaging means adjacent each opposite side end of the opening. The lens has, at each opposite side end, second engaging means adapted to snapingly engage the first engaging means; the lens is flexible in a direction enabling distance variation between the side ends thereof so that manual pressure exerted on the lens causes the lens to snapingly engage with or to disengage from the first engaging means; and removable anchor means mounted at each opposite side end of the lens receiving portion and insertable at the opposite side ends of the lens to further secure the first and second engaging means together in an engagement position. In one form of the invention, the removable anchor means are shaped, on the one hand, to fittingly receive the ends of the lens and, on the other hand, with a slot to receive therethrough the strap that serves to mount the mask to the user's head.
U.S. Pat. No. 6,047,410 issued to Dondero on Apr. 11, 2000 discusses a goggle system comprised of a lens having a series of notches which interfit with posts, two of which are seen as small cross members in a lens slot which supports and interfits with the edge of the lens. Lens slot exists in both the upper frame and the lower frame. The posts are used to better help the lens to interlock into the upper and lower frames. U.S. Pat. No. 5,809,580 issued to Arnette on Sep. 22, 1998 discusses a multi-sport goggle having a tear-away lens system comprising a "permanent" lens having opposite side edges is provided which fits within grooves formed along the top and bottom frame extents. Permanent lens is first placed into the frame as described above, with the side edges of the lens lying over the outwardly facing surfaces of side extents. Once lens is in place on frame, brackets are secured to areas as described, with top wall portions extending over lens. Each outer-most lens further includes a first pair of holes at the opposite ends of the front pane which may be aligned with and passed over knobbed posts thereby removably securing the stack of outer-most lenses over permanent lens. The lateral pull-straps are secured to one side of the goggle frame, in the manner described below, such that the wearer can successively pull at the outer-most strap, lifting the outer-most lens off of posts and thereby revealing a clean lens therebeneath as needed.
U.S. Pat. No. 5,689,834 issued to Wilson on Nov. 25, 1997 discusses goggles with a front wall frame having a lens aperture for receiving a lens assembly that would cover both the wearer's left and right eyes. A lens groove removably receives the peripheral edge of lens assembly. Goggles also have a rear frame member. Rib members have their rear ends connected to rear frame member and their front ends connected to front wall frame.
U.S. Pat. No. 5,444,876 issued to Cooper et al. on Aug. 29, 1995 discusses protective eyewear having a wrap-around type lens and a frame which surrounds the upper and side edges of the lens. The frame includes a slot to receive the lens, and the slot has spaced pawls within the slot. The lens includes mating detents within the face of the lens to receive the pawls and thus retain the lens to the frame.
U.S. Pat. No. 5,148,550 issued to Hodgkinson et al. on Sep. 22, 1992 discusses fastener means using a pair of studs affixed to the side portions with ends which are rotatable to lock and release the lens. The lens has a pair of slots formed in it for receiving therethrough the studs and once the studs are extended through the slots, the ends and are rotated to lock the lens in place. A safety lock in the form of a wire is provided for each of the studs to prevent the lens from being inadvertently detached from the field mask. The wires are extended through apertures formed in the ends of the studs and prevent the lens from being detached if the ends of the studs are rotated to a position which would permit the studs to disengage from the slots in the lens through which the studs extend.
U.S. Pat. No. 4,748,697 issued to Hodnett on Jun. 7, 1988 discusses a face mask which is characterized by a soft rubber or plastic cowl provided with a track insert having pair of tracks spanning an open lens window for receiving a transparent lens slidably mounted in the tracks and closing the lens window. In a preferred embodiment, the lens is a tear-away lens connected at a perforated interface to the next one of several additional lenses wound in end-to-end relationship in a roll, which roll is located inside a canister attached to the track insert of the face mask. Each lens is individually, selectively and sequentially extended through a slot in the canister and through the parallel lens tracks to a track lip projecting from the opposite side of the track insert, when the preceding lens is damaged or coated so as to adversely affect visibility and is removed from the lens tracks. When the damaged lens is slidably extended from the lens tracks in the face mask for removal, a second lens is unrolled from the canister and slidably positioned over the lens window and the damaged lens is torn from the leading edge of the newly positioned lens at the perforated interface between the lenses.
These prior art patents fail to teach the eye shield that can be releasably attached to a frame for a shield apparatus for quick cleaning and replacement and the other advantages of the present invention. Thus, it may be seen that these prior art patents are very limited in their teaching and utilization, and an improved shield apparatus is needed to overcome these limitations.


A purging tool is disclosed that is operable to enable a user to utilize a pumping device to create an influx of air/pressure within a fuel tank to purge blockages with a fuel tank and associated fuel lines, herein after referred to as the fuel system. The purging tool comprises an integrated pneumatic valve operable to interface with a pumping device. The purging tool may further comprise a shape operable to be easily adapted to standardized fuel inlets.

Common power tools typically utilize gasoline as a source of power. However, like many other natural fuel sources, gasoline has some known drawbacks, including susceptibility to deterioration over time. In particular, gasoline is susceptible to fuel oxidation, which may happen over the course of a few months and leads to the formation of deposits, such as gum, which may create blockages within a fuel tank and/or its associated fuel lines. This problem is particularly prevalent in gasoline containing ethanol and two-cycle engine fuel used in power tools. Formation of deposits and other contaminations can contribute to the buildup of deposits within a fuel tank. Since power tools are often left without use for extended periods, oxidation and other degradation of fuel left in the tank pose potential problems in the fuel system of such tools. Blockages due to fuel oxidation can become a serious problem for power tools. Solutions to this issue are still needed.

Purging tool with integrated pneumatic valve


A process for preparing polymer dispersions stabilized by polyvinyl alcohol includes a step of emulsion polymerization. The polymerization occurs such that at least 60% of the total conversion occurs at a temperature from 100° C. to 140° C.

1. Field of the Invention
The invention relates to a process for preparing lattices stabilized by polyvinyl alcohol, the polymer powder compositions produced therefrom, and their use in hydraulically setting systems.
2. Background Art
Polymers based on vinyl esters, vinyl chloride, (meth)acrylate monomers, styrene, butadiene and ethylene are used first and foremost in the form of their aqueous dispersions or water-redispersible polymer powders in many applications. For example such polymers are used as coatings or adhesives for a wide variety of substrates. These polymers are stabilized using protective colloids or more rarely low molecular weight surface-active compounds. Polyvinyl alcohols are generally used as protective colloids. Products formed from such polymers are used, in particular, as binders in hydraulically setting adhesives such as tile adhesives based on cements or gypsum plaster.
Dispersion powders are produced, for example, by spray drying or freeze drying of aqueous lattices. The starting materials used are dispersions which are prepared by emulsion polymerization. Typically in these processes, polyvinyl alcohols are used for stabilization. The emulsion polymerization liberates a considerable quantity of heat that has to be removed at the reactor wall via the aqueous medium and then passed to an adjacent cooling medium. Emulsion polymerization has better heat transfer behavior than bulk or solution polymerizations. Nevertheless, due to the tremendous quantity of energy, the production is subject to time restrictions in order not to allow the polymerization temperature to rise above the prescribed value as a result of insufficient heat removal. Temperatures above 100° C. are usually not intended, since such temperatures can only occur in pressure-rated reactors because of the boiling point of water. In addition, the polymerization temperature has a considerable influence on the macromolecular properties of the product and thus also on the use properties. In most cases, these properties are adversely affected by the decreasing molecular weights as the temperature increases.
DE 103 35 958 A1 describes a process for preparing polymer lattices that start the polymerization at a temperature Ts and ends it at a temperature Te. Utilization of oil-soluble initiators is essential to the invention. The dispersions described are usually emulsifier-stabilized, which is a form that is not suitable for producing dispersion powders.

Process for preparing lattices stabilized by polyvinyl alcohol


A nutritional supplement for inhibiting sensorineural hearing loss includes from about 0.25 to about 6.0 wt. % thiamin, from about 0.1 to about 10 wt. % pyridoxiyl-5-phosphate, from about 0.01 to about 10 wt. % folic acid, from about 0.025 to about 4.0 wt. % hydroxycobalamin, from about 1 to about 7 wt. % magnesium, from about 0.25 to about 6.0 wt. % zinc, from about 0.001 to about 0.02 wt. % selenium, from about 0.1 to about 10 wt. % manganese, from about 5 to about 50 wt. % ginger root P.E. 4:1, from about 5 to about 40 wt. % citrus bioflavonoids, from about 2.5 to about 40 wt. % 1-cystine, from about 5 to about 40 wt. % n-acetlyl-1-carnitine, from about 1 to about 40 wt. % alpha lipoic acid, from about 1 to about 40 wt. % coenzyme Q10, from about 1 to about 40 wt. % green tea extract, and from about 1 to about 60 wt. % resveratrol.

Sensorineural hearing loss results from damage to or deterioration of the inner ear (sensory loss) and/or damage to the auditory nerve (neural loss) which conducts the signals to the brain. Sensorineural hearing loss can be caused by diseases, birth injury, drugs that are toxic to the auditory system, and genetic syndromes. Sensorineural hearing loss may also occur as a result of noise exposure, viruses, head trauma, aging, and tumors. Except in the case of a sudden onset of hearing loss due to certain injuries, sensorineural hearing loss is generally not reversible.
It has been estimated that 80% of all cases of hearing loss are sensorineural. In the United States alone, it is believed that more than twenty two million people have enough sensorineural hearing loss to affect their ability to communicate. This form of hearing loss is particularly devastating because it affects the ability to discriminate between sounds and understand complex combinations of sounds, including speech.
Generally, sensorineural hearing loss is a cumulative disease caused by a wide range of genetic and environmental factors. The effects of these factors include degradation of the myelin sheaths enclosing auditory nerves, neurological plaque formation causing cell/neuron death/dysfunction, and cochlear receptor cell death. An individual's genetics determine the threshold resistance of the cochlear system and associated neurons to cumulative damage before the effect of environmental and external factors. Predisposition to sensorineural hearing loss may be evidenced by ear-specific genetic variations that may be inherited variations, whether dominant, recessive and/or sex-linked. Some individuals may have a genetic predisposition to spontaneous mutation.
Known genetic variations may have a number of effects contributing to sensorineural hearing loss. These variations may result in improper enzyme or cell physiology including deficient enzyme function in neural myelination, ineffective or malformed membrane transporters for intracellular nutrients such as thiamine, poor native production of native anti-oxidants such as dismutases and synthases. Other effects may include increased production of super-oxides, hydroxyls, and other damaging molecules and radicals, decreased mitochondrial health secondary to genetic coded enzyme misconformation and ineffective metabolic degradation of toxins, evidenced in certain individuals that have a greater sensitivity to a type of antibiotics called aminoglycosides.
Genetic variation may result in poor cell membrane stability, impaired cellular microstructure with poor microcirculation exacerbating all of these effects. Systemic genetic diseases such as diabetes may result in the formation of glycation products leading to respiratory burst enzymes e.g., superoxide anions. Similarly, hypertension may result in upregulation of NAD(P)H oxidase, a source of superoxide anions. Superoxides and similar reactive oxygen species can cause oxidative damage to cell structures. Hydroxyl radicals can damage cell membranes and lipoproteins by lipid peroxidation. Radical oxygen species can damage proteins, leading to structural changes and loss of enzyme activity.
Environmental and other external factors may contribute to cumulative damage to inner and outer hair cells, cochlear mitochondria, membrane stability and the vascular supply to cochlea and nerves. Continuous exposure to noise levels above 85 dB will cause gradual hearing loss in some individuals. Even a single exposure to higher noise levels may cause damage. Certain medications such as aminoglycosides, vancomycin, furosamide, and chemotherapeutic agents can damage the cochlea system. Infections such as meningitis, mumps, measles, other viral and bacterial infections, allergic reactions, exposure to ionizing radiation and autoimmune deficiencies can all contribute to sensorineural hearing loss.
The concept that sensorineural hearing loss may result from the cumulative affect of multiple insults prior to manifesting irreversible damage is well recognized and described. These multiple insults gradually wear down the buffer zone between normal auditory function and the onset of hearing loss. Age is associated with hearing loss because longer life translates into more cumulative exposures to causes of the loss. If there is a family history of hearing loss, e.g. a genetic predisposition to any of the many factors that can result in sensorineural hearing loss, the buffer between normal function and deterioration is smaller than in non-genetic cases.


A system includes a host that may be used to interface with an advanced technology attachment (ATA) device. The host includes at least one timer used to determine when to place the ATA device in a low power mode independently of an operating system (OS).

Computer systems are becoming increasingly pervasive in our society, including everything from small handheld electronic devices, such as personal data assistants and cellular phones, to application-specific electronic devices, such as set-top boxes, digital cameras, and other consumer electronics, to medium-sized mobile systems such as notebook, sub-notebook, and tablet computers, to desktop systems, workstations, and servers. Computer systems typically include one or more processors. A processor may manipulate and control the flow of data in a computer. To provide more powerful computer systems for consumers, processor designers strive to continually increase the operating speed of the processor. As processor speed increases, the power consumed by the processor tends to increase as well.
One approach to reducing overall power consumption of a computer system is to change the focus of power reduction from the processor to other devices that have a significant impact on power. These other devices may include, for example, a display, an input/output (I/O) device, a memory, etc. Typically, to reduce the power consumption of these devices, the operating system (OS) may be configured to detect the happenings or absence of certain events before reducing the power consumption of the devices. For example, the OS may indicate to a device driver that it is time to place a device into a standby state or any other low power states. The device driver may then issue commands to put the device into a low power state. This approach may not be efficient because it may take sometimes before an idle device receives the commands from the device driver. Techniques are being developed to make this process more efficient.

Method and apparatus of self-powering down ATA devices


A heel strap apparatus for securing the rear portion of a strapless shoe to the ankle of a wearer foot includes a linking strap segment having a linking strap segment first end and a linking strap segment second end, for wrapping around the back of a wearer heel; an ankle engaging portion extending from the linking strap segment for wrapping around the front of the wearer ankle to engage the ankle; and a shoe engaging portion extending from the linking strap segment for fitting around the bottom of the shoe to engage the shoe.

1. Field of the Invention
The present invention relates generally to the field of shoes and shoe accessories. More specifically the present invention relates to a heel strap apparatus for securing the rear portion of a strapless shoe to the ankle of a wearer foot to prevent the shoe from flapping against the heel of the wearer foot and to prevent a lower pant leg from becoming caught between the heel of the wearer foot and the shoe, the heel strap apparatus including a shoe engaging bottom loop for fitting around the bottom of a wearer shoe and a heel engaging back loop for fitting around the back of the heel of a wearer foot. The strap apparatus is provided in left and right hand configurations respectively for wearer left and right feet, and includes a substantially H-shaped strap harness including a linking strap segment defining the heel engaging back loop, having a linking strap segment first end and a linking strap segment second end, for wrapping around the back of a wearer ankle, an ankle engaging portion for wrapping around the front of the wearer ankle to engage the wearer ankle and a shoe engaging portion defining the shoe engaging bottom loop for wrapping around the bottom of the wearer shoe to engage the wearer shoe. The ankle engaging portion preferably includes an ankle strap segment extending from the linking strap segment first end for wrapping forwardly around the wearer ankle, and an ankle strap segment anchor structure extending from the linking strap segment second end including an ankle strap fastener for anchoring the free end of the ankle strap segment to secure the apparatus to the wearer ankle. The shoe engaging portion preferably includes a first shoe strap segment extending from the linking strap segment first end and a second shoe strap segment extending from the linking strap segment second end, and a shoe strap segment fastener for interconnecting free ends of the first and second shoe strap segments to secure the apparatus to the wearer shoe. The ankle strap segment and the first shoe strap segment preferably diverge in a Y-configuration from the linking strap segment first end, and the ankle strap segment anchor structure and the second shoe strap segment preferably diverge in a Y-configuration from the linking strap segment second end. A method of apparatus mounting is also provided.
It is believed that most wearers would prefer placement of the linking strap segment first end at the outward side of the wearer foot, and this requires the present left and right hand versions of the apparatus. The wearer, of course, has the option of interchanging the left and right hand versions to place the linking strap segment second ends at the outward sides of the wearer feet.
2. Description of the Prior Art
There have previously been heel a variety of shoe strap mechanisms. One such device is disclosed in Bricker, U.S. Pat. No. 6,651,359, issued on Nov. 25, 2003, the form of an interchangeable shoe strap system for altering the decorative look of a shoe. Ritter, et al., U.S. Pat. No. 6,772,541, issued on Aug. 10, 2004, teaches a footwear securement system for closed footwear which implements a strap having an X-configuration across the instep of the wearer foot. What is needed is a heel strap apparatus which provides a connection between the heel of a wearer foot and the heel of a strapless flat or high heel shoe, and holds them in abutting relation to prevent the shoe from slipping off the wearer foot, and providing the wearer with improved comfort while using strapless, heeled or flat shoes. Further, what is needed is a heel strap apparatus which is removable and portable, giving its wearer the option to wear strapless shoes as originally designated and, when additional comfort is desired, may be put on quickly and used without modification to the existing shoe.
It is thus an object of the present invention to provide a heel strap apparatus which secures the rear portion of an existing strapless shoe to the ankle of a wearer foot to hold the shoe against the foot and thereby prevent the shoe from flapping against the heel of the wearer foot and prevent a lower pant leg from becoming caught between the wearer heel and the shoe, and which is easily attachable and removable from an existing shoe without modification of the existing shoe.
It is another object of the present invention to provide such a heel strap apparatus which provides the wearer with enhanced comfort while using strapless flat or heeled shoes, and which helps prevent a strapless heeled shoe from slipping off the wearer foot when the wearer is performing daily activities such as walking, climbing stairs, dancing, running, jumping, and so forth.
It is still another object of the present invention to provide such a heel strap apparatus which, when the wearer has on long pants, prevents the lower portion of the pant leg or cuff from slipping between the wearer foot and the shoe.
It is finally an object of the present invention to provide such a heel strap apparatus which may be produced from a variety of materials having fashionable colors, and which optionally includes either permanent or removable decoration.

Heel strap apparatus and mounting method


A motor control device includes a table in which a motor torque generated from a reluctance torque utilizing motor is stored with respect to a combination of an armature current command value and a current phase angle command value at which the motor torque is maximized for the armature current command value, a first setting portion that sets a motor torque command value that is a command value of a motor torque to be generated by the reluctance torque utilizing motor, and a second setting portion that sets, based on the table, an armature current command value and a current phase angle command value for making a motor torque that is in accordance with the motor torque command value set by the first setting portion be generated from the reluctance torque utilizing motor.

There are known reluctance motors that rotate the rotor utilizing just the reluctance torque. Among reluctance motors are a switched reluctance motor (SRM) with which a stator and the rotor have salient pole portions and a synchronous reluctance motor (SynRM) with which the stator has the same structure as in a brushless motor.
The synchronous reluctance motor has salient pole portions just at the rotor out of the stator and the rotor. With the synchronous reluctance motor, in accordance with the salient pole portions of the rotor, there are a direction of a salient pole portion in which magnetic flux flows readily (hereinafter referred to as the "d-axis direction") and a direction of a non-salient pole portion in which the magnetic flux hardly flows (hereinafter referred to as the "q-axis direction"). The reluctance torque is thus generated due to a difference (Ld−Lq) between an inductance in the d axis direction (hereinafter referred to as the "d-axis inductance Ld") and an inductance in the q axis direction (hereinafter referred to as the "q-axis inductance Lq"), and the rotor is rotated by the reluctance torque.
FIG. 9 of Patent Literature 1 discloses a method of controlling a synchronous reluctance motor by vector control similar to that of a brushless motor. Specifically, an armature current command value corresponding to a motor torque to be generated in the synchronous reluctance motor and a current phase angle command value that is in accordance with the armature current command value are set. A d-axis current command value and a q-axis current command value are calculated based on the set armature current command value and current phase angle command value. The synchronous reluctance motor is then subject to current feedback control based on the d-axis current command value and the q-axis current command value.


A dielectric material having a low dielectric loss factor for high-frequency use, which comprises a sintered product of silicon nitride chiefly composed of silicon nitride and containing at least oxygen as an impurity component or oxygen as an impurity component and a compound of an element of the Group 3a of periodic table, wherein said sintered product contains aluminum in an amount which is not larger than 2% by weight reckoned as an oxide thereof having relative densities of not smaller than 97% and has a dielectric loss factor at 10 GHz ofnot larger than 5.times.10.sup.-4. The dielectric material has excellent mechanical properties such as large strength and excellent chemical stability, features small dielectric loss factor in high-frequency regions, and is suited for use as a material for high-frequency oscillators, antennas, filters and electronic circuit boards. In particular, those dielectric materials are suited for use as window materials for introducing high frequencies in a high-frequency plasma-generating CVD apparatus, a microwave wave output unit and an oscillator.

1. Field of the Invention
The present invention relates to a dielectric material having a low dielectric loss factor for high-frequency use as employed in oscillators, antennas, filters and electronic circuit boards used in high-frequency regions such as in microwave and millimeter wave regions and, particularly, to a material for windows for transmitting high frequency such as of a high-frequency plasma-generating CVD device, a microwave output unit and an oscillator used in an apparatus for producing semiconductors, apparatus for producing liquid crystals, apparatus for producing photosensitive drums, apparatus for producing diamond films, and nuclear fusion apparatus.
2. Description of the Prior Art
In recent years, dielectric ceramics for high-frequency use have been positively used as electronic components and electronic circuit boards in high-frequency regions accompanying the development and widespread use of mobile communication equipment such as cordless telephones, simple portable telephone systems (PHS), satellite broadcast receivers, as well as high-frequency equipment and devices such as CVD apparatus for producing semiconductors and liquid crystals.
From the standpoint of enhancing performance, the dielectric materials used in high frequencies must exhibit small dielectric losses at high frequencies. Accompanying the modern trend toward adapting high-frequency technology to general applications, furthermore, study has been forwarded to utilize dielectric materials under special environmental conditions such as high-temperature and corrosive conditions. It has therefore been urged to provide a dielectric material having a low dielectric loss factor for use in high frequencies featuring excellent mechanical properties, chemical stability and high reliability.
Conventional dielectric ceramic materials of the types of BaO-TiO.sub.2, MgO-CaO-TiO.sub.2 and CaO-ZrO.sub.2 having excellent dielectric properties are not yet satisfactory in regard to their mechanical properties and chemical stability. Though a variety of attempts have been made in order to improve such properties, their strengths are about 100 MPa at the greatest. Besides, the mechanical and chemical properties vary to a large extend depending upon the Young's modulus specific to the material, mode of interatomic bonding and bonding force, leaving much room for improvements.
Ceramics having excellent mechanical and chemical properties can be represented by a sintered product of silicon nitride. According to the journal of the Japanese Association of Precision Engineering, Vol. 53, No. 5, 1987, pp. 743-748, however, the sintered product of silicon nitride used for general mechanical parts exhibits a dielectric loss factor of as large as 7.times.10.sup.-4 at a frequency of 6 GHz, and is not applicable as a dielectric material for high-frequency use. So far, silicon nitride has seldom been studied as a dielectric material.
Recently, furthermore, a microwave plasma processing apparatus has been much used chiefly in the CVD, etching and resist steps in the production of semiconductors, liquid crystals and thin films. In a high frequency generator e.g., gryotron) used for nuclear fusion, furthermore, millimeter waves in excess of 20 GHz are output and are introduced into the nuclear fusion furnace to generate a plasma of high energy.
A window transmitting high-frequency waves constituted by a material having good high-frequency permeability is used for the high-frequency introduction portion and output portion of the apparatus that generates plasma using high frequencies such as microwaves or millimeter waves. Such an introduction window and an output window (hereinafter referred to as transmitting windows), however, must have high-frequency transmission properties (low dielectric constant, low dielectric loss) as well as heat resistance to withstand a rise of temperature and a rapid change in temperature, thermal shock resistance and air-tightness for maintaining vacuum. In recent years, it has been urged to provide production apparatus featuring high productivity. In order to accomplish nuclear fusion, furthermore, a plasma of a high temperature must be produced requiring large electric power of high frequencies. Therefore, it has been demanded to provide windows having higher performance and higher reliability to meet such tendencies.
These windows have heretofore been composed of a quartz glass, alumina ceramics, single crystalline alumina (sapphire), aluminum nitride (AlN) or beryllia (BeO) having low dielectric constant, small dielectric loss and high density by giving importance to high-frequency transmission properties and air-tightness for maintaining vacuum.
However, these materials all have poor thermal shock resistance. When a large electric power of a high frequency is transmitted, furthermore, the window is locally heated giving rise to the occurrence of cracks or pinholes due to melting, resulting in a decrease in the air-tightness for maintaining vacuum.
In order to solve these problems, the surfaces of the windows have been coated with, for example, a film of TiN or a film having high thermal conductivity from the standpoint of preventing an increase in temperature on the surfaces of the windows. Or, it has been proposed, from the standpoint of increasing strength, to produce a window material using alumina ceramics as disclosed in, for example, Japanese Laid-Open Patent Publication No. 345527/1994 or using an alumina-zirconia composite material as disclosed in Japanese Laid-Open Patent Publication No. 280976/1992. These ceramics, however, have a thermal shock resistance of as low as about 200 to 300.degree. C., which is not sufficient from the standpoint of reliability. Besides, cracks easily develop in the windows impairing mechanical reliability and making it difficult to dear with large electric power at high frequencies.
There has further been known a silicon nitride (Si.sub.3 N.sub.4) ceramics materials used for which exhibits far superior heat resistance, thermal shock resistances and mechanical properties to those of the above-mentioned ceramics. However, the silicon nitride has been used as structural components but has not been studied in regard to being used as a window material for introducing high frequencies by reason of having a high dielectric loss.
In order to obtain a material having a high strength and a low dielectric loss factor in a high-frequency band, the present inventors have forwarded the study extensively to decrease dielectric loss by using a sintered product of silicon nitride that has excellent mechanical and chemical properties but a large dielectric loss factor. As a result, the inventors have discovered the fact that the dielectric loss factor at 10 GHz can be decreased down to not larger than 5.times.10.sup.-4 if the content of aluminum that is inevitably contained as impurities in the sintered product of silicon nitride is suppressed to be smaller than a predetermined amount and that there can be obtained an excellent material having a small dielectric loss factor that is suited for use in high frequencies, and have thus arrived at the present invention.
The inventors have further discovered the fact that particularly excellent properties are obtained when a material of the present invention is used and, particularly, when a material of the invention having a relative density of not smaller than 97% and a dielectric loss factor of not larger than 5.times.10.sup.-4 is used as a window for high frequencies such as in the aforementioned CVD apparatus, microwave output unit and oscillator.

Dielectric material having a low dielectric loss factor for high-frequency use


Ways to mitigate loss in inter-operability scenarios for digital video are presented. For example, a bitstream modification tool (such as a bitstream rewriter running on a network node of a videoconferencing system) receives an incoming bitstream of encoded video (e.g., from an encoder that uses a first loss recovery strategy). The bitstream modification tool processes the incoming bitstream of encoded video to produce an outgoing bitstream of encoded video. In doing so, the bitstream modification tool changes at least one syntax element between the incoming bitstream and the outgoing bitstream so as to mitigate picture loss effects during decoding of the outgoing bitstream under lossy delivery conditions. The bitstream modification tool outputs the outgoing bitstream. In this way, the bitstream modification tool can help avoid blank screens, frozen screens, or other failures during decoding under lossy delivery conditions (e.g., with a decoder that uses a different loss recovery strategy).

When video is streamed over the Internet and played back through a Web browser or media player, the video is delivered in digital form. Digital video is also used when video is delivered through many broadcast services, satellite services and cable television services. Real-time videoconferencing often uses digital video, and digital video is used during video capture with most smartphones, Web cameras and other video capture devices.
Digital video can consume an extremely high amount of bits. Engineers use compression (also called source coding or source encoding) to reduce the bit rate of digital video. Compression decreases the cost of storing and transmitting video information by converting the information into a lower bit rate form. Decompression (also called decoding) reconstructs a version of the original information from the compressed form. A "codec" is an encoder/decoder system.
Over the last two decades, various video codec standards have been adopted, including the ITU-T H.261, H.262 (MPEG-2 or ISO/IEC 13818-2), H.263, H.264 (MPEG-4 AVC or ISO/IEC 14496-10), and H.265 (HEVC or ISO/IEC 23008-2) standards, the MPEG-1 (ISO/IEC 11172-2) and MPEG-4 Visual (ISO/IEC 14496-2) standards, and the SMPTE 421M standard. A video codec standard typically defines options for the syntax of an encoded video bitstream, detailing parameters in the bitstream when particular features are used in encoding and decoding. In many cases, a video codec standard also provides details about decoding operations a decoder should perform to achieve conformant results in decoding. Aside from codec standards, various proprietary codec formats (such as VP8, VP9 and other VPx formats) define other options for the syntax of an encoded video bitstream and corresponding decoding operations. In general, a codec standard or format allows an encoder made by one company to inter-operate with a decoder made by another company. Content encoded by the encoder of the first company can be successfully decoded by the decoder of the second company under normal operating conditions, so long as both companies have followed the relevant guidelines in the codec standard or format.
Some operations of a decoder are outside a codec standard or format, however. Such operations can vary depending on implementation, which means different decoders can implement the operations in different ways. In particular, different decoders may use different strategies to recover from the loss of encoded data (e.g., due to network congestion) during decoding. As a result of these differences in implementation, an encoder that uses one loss recovery strategy may encounter unexpected problems when inter-operating with a decoder that uses another loss recovery strategy. For example, during videoconferencing, content encoded with an encoder that uses one loss recovery strategy may be delivered to a decoder that uses the same loss recovery strategy and/or to a decoder that uses another loss recovery strategy. When encoded data is lost due to network congestion, the decoder that uses the same loss recovery strategy may quickly recover from the loss of encoded data, while the decoder that uses the other loss recovery strategy shows a blank screen or frozen screen for several seconds, or even fails to recover, requiring a time-consuming restart of the decoder.

Mitigating loss in inter-operability scenarios for digital video


The present invention is directed to a method and system for managing the coherency of mirrored storage volumes, including a method and system for restoring coherency in the event of communication disruption between the primary volume and the secondary volume mirroring the data on the primary volume. The system includes a primary and a secondary storage controllers for managing the primary and secondary storage volumes. The storage controllers are capable of performing cyclic redundancy checking scans of their respective storage volumes and comparing the results to determine data from the primary storage volume needed to update the secondary storage volume so that it mirrors the primary storage volume.

Currently, information handling systems are often integrated into groups with multiple users accessing and storing data. For various reasons, groups of information handling system users may be located in separate areas such as in different offices, or in different geographic locations. Even with multiple users located in separate locations the need may arise to generate a unified data storage system. For example a common database of information may be desirous, such as a customer database for a business with different geographic locations. As a result, different storage volumes may need to be maintained and integrated to store and manage data.
When common volumes of information are stored a back-up of data may be needed such as by using other data storage volumes mirroring the primary storage volume to protect the data in the case of natural disasters, data corruption or the like. Additionally, the separate user locations may need to continue to function should a disruption in communication occur between the various locations.
Should a disruption in communication occur, the storage volumes may become incoherent, and as a result a secondary, mirroring storage volume may no longer represent the data on the primary storage volume. If the primary and the secondary storage volumes no longer mirror each other the need to reestablish coherency would require the communication of the data stored on the primary volume to the secondary volume. A transmission of the primary volume to the secondary volume is undesirous due to the typically large volume of information and the time required to transmit.
Presently, to avoid the need to communicate the contents of the primary storage volume in the event of a break in communication, a bitmap is typically maintained to track the changes in the primary volume while communication between the primary and the secondary volumes is disrupted. A bitmap is utilized to provide a list of changes occurring to the primary storage volume so that the data written to the primary volume may be updated to the secondary volume when communication is reestablished. Thus, the need to transfer the entire contents of the primary storage volume to the secondary storage volume upon reestablishment of communication is eliminated. Generally, bitmaps of mirrored storage volumes are maintained in non-volatile memory to ensure their protection in the event of a power failure. Additionally, bitmaps are maintained in non-volatile memory because the mirrored storage volume system had no other method for establishing coherency besides transmitting the contents of the primary storage volume to the mirroring storage volume. Thus resulting in an input/output intensive operation.
Therefore, it would be desirable to provide a mirrored storage volume system capable of eliminating the need for a costly, time consuming non-volatilite stored bitmap system and method for ensuring the coherency of mirrored volumes or in the alternative a mirrored volume system in which a bitmap may be maintained in volatile memory.

Cyclic redundancy checking for managing the coherency of mirrored storage volumes