A method and system for implementing an inter-Access Network (AN) handoff in an active state in a High Rate Packet Data (HRPD) Network. The method mainly includes determining that an inter-AN handoff operation is necessary and initiating a handoff procedure to perform the inter-AN handoff, sending data to be transmitted to an access terminal to the destination AN in advance in the handoff procedure, and then sending the access terminal the data to be transmitted to the access terminal by the source AN or the destination AN according to the result of the handoff procedure. With the method according to the present invention, the continuity of a service may be improved. Even if the inter-AN handoff procedure fails, the source PCF may send data information obtained upon the start of the handoff to the access terminal when the access terminal returns to the source AN since the source PCF may receive data from the PDSN throughout the handoff procedure. As a result, the continuity of a service may be improved.

With the development of communication technologies, the 3rd Generation Partnership Project 2 (3GPP2) proposed a standard for HRPD technology in order to solve the crucial issue on air interfaces in a Code Division Multiple Access (CDMA) system. This standard aims to improve the data transmission rate on a wireless interface. Compared with the data rate of 153.6 kbit/s provided by CDMA 2000 1x, the HRPD technology may provide a forward data rate up to 2.4 Mbit/s.
In an HRPD network, a new modulation technique is utilized over air interface and methods for data rate control, scheduling optimization and time division multiplex and the like are added, which cause a significant improvement in data transmission rate over air interface. In the HRPD technology, a private data channel on a CDMA carrier (1.25 MHz) may be employed to support high rate packet data services, with a forward data rate up to 2.4576 Mbit/s, and a peak data rate of 153.6 kbit/s for a single user supported in reverse direction.
A separate carrier is needed to support HRPD when deploying an HRPD network. In this manner, when moving in the HRPD network, an access terminal may move from one AN into another AN in the HRPD network. At this time, a handoff from a source NA to a destination NA is necessary.
Currently, the 3GPP2 standard supports only the inter-AN handoff in dormant state. This handoff process is as follows: when an access terminal performing a data service in an HRPD network moves to an edge of the coverage zone of a cell, it is necessary to be handed off to another AN so as to continue its data service. At this time, the system switches the packet data service from an active state to a dormant state at the source AN, and then hands off to the destination AN in the dormant state. After moving into the destination AN, the system switches the packet data service from the dormant state back to the active state at the destination AN.
With the above handoff process, a handoff operation from a source AN to a destination AN may be implemented. However, for a data service with high real-time requirement, such as Voice over IP (VoIP), Video Phone, Push-To-Talk (PTT) and stream media, such a handoff process may cause an interruption of the service, which will result in an adverse effect to the utilization of the service for the user.
In other words, in the method of inter-AN, inter-Packet Control Function (PCF) handoff in dormant state provided in the prior art standard, it is necessary to release the Point-to-Point Protocol (PPP) connection being in use during a handoff process, and thus it is necessary for the Packet Data Service Network (PDSN) to reallocate a new PPP connection for the destination network. During the reallocation of the new PPP connection, for one thing, the service of the user may be interrupted due to the failure of the reallocation process resulted from problems of the resources; for another, the current service of the user may be delayed significantly because it will cost the PDSN some time to reestablish a PPP connection.
In view of this, a hard handoff process is required to ensure the continuity of a service during an inter-AN handoff process. However, in the prior art standard, only an inter-AN handoff process in dormant state is defined, and there is a lack of an inter-AN, inter-PCF hard handoff process in an active state in an HRPD system.

Method and system for implementing inter-access network handoff in active state in HRPD network


A system for deicing a wind turbine blade includes an electrically powered active plasma actuator applied to a desired portion of a wind turbine blade. The activated plasma actuator energizes the air in the vicinity of the plasma actuator to increase the surface temperature of the wind turbine blade in the vicinity of the plasma actuator sufficiently to reduce or eliminate the collection of ice on a desired portion of the wind turbine blade.

The invention relates generally to wind turbines, and more specifically to use of a plasma actuator that operates without an external source of air other than ambient air to modify wind turbine boundary layer separation to energize retarded flows and to reduce the collection of ice over wind turbine blades.
Boundary layer separation takes place over highly curved surfaces for flows at high-angles of attack. This characteristic contributes to loss of pressure and hence a decline in aerodynamic efficiency of a wind turbine. In cold areas, collection of ice on the wind turbine blades not only contributes to loss of pressure, but also is hazardous.
Different techniques have been employed to modify the boundary layer interaction to control flow characteristics. Many of these well known techniques use passive methods and devices, while some others use piezo electric surface modifications for flow control. One known technique employs Dielectric Bather Discharge (DBD) devices to modify boundary layer interaction to control flow characteristics associated with an air induction system for an aircraft. Another known technique employs surface cavities to modify the boundary layer growth to mitigate flow losses.
Currently, there are no techniques used to overcome boundary-layer separation and simultaneously deice wind turbine blades. Vortex generators have been used to passively delay flow separation; but a major disadvantage to this solution is the vortex generator enhanced flow, even in situations where delaying flow separation is no longer desired.
In view of the foregoing, it would be advantageous to provide a method to actively control flow separation and deice wind turbine blades. The method would employ a plasma actuator that is compact with no exposed moving parts, that operates without an external source of air other than ambient air, that requires little power to operate, that provides more versatility than passive techniques, and that can be applied to existing devices such as, without limitation, fan blades and turbine blades, with only minor modifications(s).

System and method of deicing and prevention or delay of flow separation over wind turbine blades


An exemplary method implemented by a first end-user communication device receives an electronic communication of a digital packet having a header segment and a user data segment, the user data segment containing a user message and a priority value A first message priority is determined by a first module of a enhanced services application program. The first message priority is based on the received priority value that defines first visual indicia representing a first priority for the user message, a plurality of different message priorities with associated different visual indicia being defined by corresponding priority values. Under the control of the first module, the user message concurrent with the first visual indicia are displayed on a screen segment of the first end-user's communication device so that the first priority assigned to the received user message is visually conveyed to the first end-user.

This invention relates to communications among end user communication devices and more specifically to the priority of user data processed by end user communication devices, especially but not limited to, wireless end user communication devices, which may be made by different manufacturers and/or have different operating systems.
Wireless communication devices are now prevalent throughout all developed countries of the world. Although cellular telephones are currently the most widespread, other types of wireless communication devices include personal digital assistants, laptop computers with Wi-Fi and/or telecommunication carrier communication support, and various types of "pads" that provide visual displays that are larger than conventional cellular telephones but typically smaller than the displays of a laptop computer. Wireless voice communications between mobile devices utilizing different types of communication protocols, e.g. analog, TDMA, CDMA, VOIP, etc., are supported by different telecommunication carriers which provide appropriate communication protocol interfaces/gateways to facilitate voice communications between mobile units using different communication protocols.
Various types of transport layer communication protocols are supported by wireless communication devices. For example, text messaging, short messaging service (SMS), multimedia messaging service (MMS), email such as by simple mail transfer protocol (SMTP), and instant messaging utilizing hypertext transfer protocol (HTTP) are available. Each type service is supported by a transport layer communication protocol that is part of the telecommunication signaling structure associated with the transport of user communications and the communication of telecommunication infrastructure commands and signals.
Some email client programs support setting an importance level of an email message by the message originator. For example, importance levels can be "high, normal, low". However, various email clients may not recognize an importance level originated by a different email client or may provide different types of treatment of the message than intended by the originator. In Microsoft Outlook email client the importance level determines the order in which emails are transmitted from the client, i.e. an email with a high importance level will be transmitted ahead of an email with a normal or low importance level even if the latter was stored in a holding queue ahead of the former. Also, an importance level is generally required to be processed by a server disposed in the transmission path between the originator and recipient in order to convey the importance level to the recipient. For example, a Microsoft Exchange Server transmits messages received from a Microsoft Outlook client to the corresponding destinations from a holding queue in an order based on importance level so that higher importance level messages are transmitted ahead of lower importance level messages even if the latter were received prior to the former.

Priority of received messages communicated among end user communication devices


The present invention teaches a hands free headset of small size. With the headset is a base transceiver unit which connects to the cell phone or other device having audio input and output. The base transceiver unit may advantageously contain a rechargeable battery to allow for mobile operation, the headset transceiver unit may also use a small rechargeable battery (“coin size”) for reduced size and easy recharging. The base transceiver unit may communicate with the headset via half or full duplex transmission and reception. This may also be achieved in alternative embodiments by digitally encoding one or both of the signals and transmitting them as digital data. The antenna of the headset unit may be located on or within the microphone tube, thus allowing a reduced headset size. The base transceiver unit, which may be plugged into electrical power wiring continuously or may be completely mobile may also save energy in the form of electricity by avoiding an unnecessary “trickle current”. The battery in the base transceiver unit, and the battery in the headset, may both be inductively recharged in the present invention. Another space, weight and cost saving feature of the present invention is the ability to automatically control volume. Automatic volume control allows elimination of external volume control structure yet still allows volume control to occur. In the present invention, volume is controlled by the base device attached to the base transceiver unit. By this means, battery life may be extended yet without the cost and bulk of an external control device such as a switch of a size suitable for a user's fingers to operate.

Cellular telephones, while convenient, require the user to use one hand to hold the telephone in proximity to ear and mouth in order to use the telephone. In addition, when the user wishes to use a cell phone control such as the alphanumeric keypad, the user must take the cell phone from their ear and transfer it to a location in which they can see the keypad and push buttons as needed. In addition to inconvenience and distraction from contraindicated activities such as driving, this is a two handed process. These problems are not restricted to cellular telephones as a growing number of types of devices offer users audio input and output data. Personal computers and personal digital assistants, as two examples, offer increasingly efficient speech recognition. Digital and tape recorders, which do not offer voice recognition, are also examples of the types of devices which may increasingly be voice activated and may even offer preprogrammed voice output.
The requirement of holding a device such as a cell telephone to the ear in turn causes various other problems, safe operation of motor vehicles being one major example of such issues, tiredness by the user's arm being a less important type of problem. For these reasons and others, vendors and inventors are offering a range of solutions to the problem of "hands free" cell phone operation.
One attempt to solve this problem is the "hands free cell phone" in which the volume of the audio output and the sensitivity of the audio input are dramatically increased. The user places the cell phone or other device in a special holder or merely places it on seat or dashboard and speaks loudly. Such systems have numerous disadvantages: audio feedback, ambient interference and poor sound quality, among others. Lack of privacy is increasingly an issue as well, since both sides of the conversation are clearly audible to anyone nearby.
One more promising route for improvement is the use of the headset. By wearing earphones and a microphone, a user can escape the need to continuously hold the cellular telephone or other audio input/output device. Unfortunately, headset cords connecting the headset to the base device can entangle the user's hands, arms, or whatever they may be using, such as a computer keyboard or steering wheel, thus posing a threat on their own. The solution to this problem is the wireless headset, in which the headset device and base device communicate by means of RF transmissions.
Wireless headsets offer a potentially life saving hands free mode of operation for motor vehicles and other activities which require continuous active use of two hands. The user wears the wireless headset with microphone and speakers, leaves the base unit safely tucked away, and is in no danger of having one or more hands entangled in a cord or used to control the base device. This life saving ability is of increasing importance as the number of cell telephones on the road proliferates and drivers increasingly ignore safety (and in some jurisdictions the law) in order to use their telephone, computer, recorder or other device. Other situations than driving may also show the life saving features of the present invention: skiing, bicycling, operation of industrial machinery, printing presses, civil engineering equipment, etc.
And in yet a broader range of applications, the device of the present invention may be used to provide convenience and increase productivity: secretarial work, telemarketing, office work, etc.
Various wireless headsets schemes have been proposed. In general, the problem with most headsets is size, bulk, and lack of ease of use. The following prior art head sets show these disadvantages.
U.S. Pat. No. 4,882,745 issued Nov. 21, 1989 to Silver for "CORDLESS HEADSET TELEPHONE" shows one early telephone headset in the context of a conventional land-line telephone. The headset disclosed has a large ear piece, telescoping antennas in both base unit and headset, and a cross section so large as to include a keypad on the headset portion of the device. The '745 patent teaches only that charging of the headset battery is accomplished by means of contacts 29 seen in FIG. 2 and FIG. 5. The headset also includes on/off switches and a manual volume control.
U.S. Pat. No. 5,590,417 issued Dec. 31, 1996 to Rydbeck for "RADIOTELEPHONE APPARATUS INCLUDING A WIRELESS HEADSET" teaches a headset in which recharging is accomplished when the headset is attached to the base transceiver unit. The gain control of the headset is accomplished manually by means of controls in the base transceiver unit, as discussed in column 4 at lines 38 through 59. Two embodiments are taught in both of which manual control of headset output volume is accomplished manually at the base transceiver unit.
U.S. Pat. No. 6,078,825 issued Jun. 20, 2000 to Hahn et al. for "MODULAR WIRELESS HEADSET SYSTEM FOR HANDS FREE TALKING" and U.S. Pat. No. 6,230,029 B1 issued May 8, 2001 to Hahn et al. for "MODULAR WIRELESS HEADSET SYSTEM" disclose a headset having battery contacts used to charge the removable battery pack module. These patents also teach that the headset have manual on/off, channel and volume controls.
Finally, US Patent Application Publication No. US 2001/0016506 A1 published Aug. 23, 2001 in the name of Son et al. and entitled "WIRELESS HANDS-FREE SYSTEM OF CELLULAR PHONE" teaches a battery operated hands free headset having a battery saving feature described in paragraph 0014. No indication of any means of charging of the battery is present in the publication, and as specified in the final phrase of paragraph 0013, a switch on the headset is operated by the user.
These devices all require either changing of the batteries or plugging the batteries into some type of charger arrangement having contacts, springs, sockets or other devices. In addition, the structure which allows changing of the batteries or charging of them (the contacts, sockets, access panels, etc) all add cost, weight and complexity to the headsets. However, the objective of having such headsets is simplicity, small size, light weight, and ease of use.
In addition, the size and weight of these headset devices is increased by the use of various ancillary devices such as on/off switches, volume controls, etc, the functions of these device can be better handled by means of different and smaller structures.
Finally, none of the devices disclosed teach a method by which the "trickle current" which the base transceiver unit uses may be turned on and off. None of these devices teach that the "trickle current" powering the wireless device may be turned off when not in use, yet leave the base device (such as a telephone) turned on, and further have the wireless device be available for use whenever the base device is used. Such "trickle currents" in consumer electronic devices such as VCRs, televisions, computers, caller ID boxes, and so on are now known to be a cumulatively large source of energy wastage in the form of electricity generated and supplied to homes and businesses and wasted to power LCDs and other circuitry in such consumer devices while the devices are not in use.


The present invention relates to an apparatus and method for estimating a channel in a wireless communication system. The apparatus according to the present invention includes an estimator for initially estimating a channel response value by using a predetermined signal among reception signals, a detector for detecting transmission signals by using the channel response value and an operator for updating the channel response value by using detected transmission signals, a detection accuracy and reception signals.

Generally, a channel estimation method in a wireless communication system is classified into a training-based channel estimation method using a preamble signal or a pilot signal, a semi-blind method additionally using a data signal after using properties of the preamble signal, the pilot signal or other predetermined signals, and a blind method using only a received data signal without predetermined signals.
If the blind method is employed, a throughput due to channel estimation is not deteriorated since additional signals are not used. However, the blind method uses properties of the received signal only, thus reducing channel estimation performance, especially in the case of rapid change in channels. Regarding the training-based method, as it uses the predetermined signals, it provides the best channel estimation performance but requires additional signals in proportion to the number of transmission antennas. Hence, it has a problem that the throughput tends to deteriorat according to the increased number of transmission antennas or according to the enhancement of estimation performance. Meanwhile, as the semi-blind method estimates a channel by using the data signal together with the preamble signal or the pilot signal, additional overhead due to the enhancement of channel estimation performance does not occur and therefore the throughput is not reduced.
An accurate channel estimation is required to detect multiple signals or to effectively remove an interference signal of a neighboring cell in a multi antenna wireless communication system or a cellular system having a frequency reuse rate of 1. In the multi antenna wireless communication system, a terminal using a plurality of reception antennas uses a channel response in order to classify signals generated by spatial multiplexing or space-time coding from a plurality of transmission antennas. In the cellular system having the frequency reuse rate of 1, a terminal at a cell boundary has a difficulty in receiving multiple signals from a serving base station due to an interference signal from a neighboring base station and the channel deterioration with the serving base station. Thus, the base station generally transmits the same data to the terminal at the cell boundary through a plurality of transmission antennas to thereby improve reliability in signal reception of the terminal. In this case, the terminal at the cell boundary determines the interference signal of the neighboring base station and the signal from the serving base station as the multiple signals transmitted by a transmission terminal employing the plurality of transmission antennas virtually and employs an interference removal technique, thereby removing the interference signal from the neighboring base station.
For example, the semi-blind method includes expectation maximization (EM) and decision directed (DD). The EM is a method of estimating a channel response which is in the closest proximity to a received data signal in probability. The DD is a method of detecting a channel response estimated by an initial pilot signal or a preamble signal and then updating the detected channel response according to a channel change by using a received data signal. That is, the DD method considers the detected signal as a transmitted signal and estimates a channel change by applying a general channel estimation method. An area which satisfies coherence time and coherence bandwidth having an equal channel response is formed as a group. If the number of data sub-carriers in the group is larger than that of pilot or preamble signals, it can be expected to enhance channel estimation performance with noise mean effects. However, if a multiple input multiple output (MIMO) signal is not correctly detected, it has a problem of deteriorating the channel estimation performance because it estimates a channel with the incorrect information.
The EM method improves channel estimation performance by using the initially-estimated channel response and the received data signal. According to the EM, it is assumed that each signal in a constellation is transmitted with the same probability. The EM estimates a channel by accumulating the values obtained by multiplying the respective channel responses assuming each constellation point as a transmission signal, by a weight value according to a distance between the received signal and the respective constellation points. Here, since all constellation points are used, if the number of the transmission antennas or the number of the neighboring base stations is T and the number of the constellation points is |C|, the EM estimates a |C|T number of channel responses, which is highly complicated. On the assumption that noises added to each data signal are based on the same Gaussian distribution, each data signal is accumulated by the same weight. However, the noise property of the data signals may not be identical in a moment although it is identical statistically. Therefore, it is not preferable to assign the same weight. In the MIMO system, a signal which is received through a single reception antenna is represented by a combination of the channel responses multiplied by the T number of transmission signals, and noises. That is, since T numbers of channel responses are estimated by using the probability value of the data signal which is not orthogonal, the optimal result (i.e., the accurate channel response) is not obtained.

Apparatus and method for estimating channel in multi antenna wireless communication system

Chung-Ang University Industry-Academy Cooperation Foundation


The invention is directed to an ignition coil for an internal combustion engine which includes a columnar member having a plurality of magnetic plates, e.g., silicon steel plates stacked one on the other with stacked portions formed on the magnetic plates. The magnetic columnar member includes a first portion having a plurality of magnetic plates stacked one on the other in accordance with increase of a width of each plate, a second portion connected to the first portion and having a plurality of magnetic plates with the same width stacked stacked one on the other, and a third portion connected to the second portion and having a plurality of magnetic plates stacked one on the other in accordance with decrease of a width of each plate, thereby to form the columnar member with a middle portion thereof having a substantially circular cross section. The ignition coil further includes a primary winding and a secondary winding which are wound around the columnar member, a magnetic cylindrical member in which the columnar member is received. A plurality of rectangular recesses are formed on one side of each magnetic plate, and a plurality of rectangular protrusions are formed on the other side of each magnetic plate, to form a plurality of rectangular stacked portions on the columnar member.

1. Field of the Invention
The present invention relates to an ignition coil for use in an internal combustion engine, more particularly to an ignition coil having a columnar member with a plurality of magnetic plates stacked one on the other, and a primary winding and a secondary winding wound around the columnar member.
2. Description of the Related Arts
Recently, an ignition coil having a columnar configuration has been proposed so as to place the ignition coil within a cylindrical plug hole formed in an internal combustion engine. In Japanese Patent Laid-open Publication No. 4-87311, for example, there is disclosed an ignition coil having a central core assembled by a plurality of wires made of magnetic material to form a columnar configuration. In that publication disclosed are various methods for producing the central core assembled by the wires, such as a method for drawing the wires through a cylindrical die, a method for placing the wires between an upper die and a lower die, and then pressing them to form the core, a method for aligning the wires and pressing them in dies together with metallic powder, with resin powder adhered thereto, a method for placing the wires within a silicon steel pipe and then drawing the pipe through a die while heating them, and a method for rolling a silicon steel plate double or triple and then drawing it through a die. In that publication, also disclosed is a central core which is assembled by a plurality of wires to form opposite end portions having a rectangular cross section and a middle portion having a circular cross section.
As disclosed in the Publication No. 4-87311, when the ignition coil is to be formed in a cylindrical shape, it is desirable to form the central core or inner core also in the cylindrical shape. However, the methods for assembling a plurality of wires as described above can not be easily made, so that any of the methods will result in increase in cost.
Supposing that a conventional process for stacking a plurality of steel plates is employed to form a columnar core, the core will be formed as shown in FIGS. 13-16. That is, a plurality of silicon steel plates MPx having different width from one another are formed as shown in FIGS. 13-16. A recess is formed on one side of each steel plate MPx, and a protrusion is formed on the other side of each steel plate MPx. The silicon steel plates MPx are stacked one on the other under pressure to form an inner core 10x having stacked portions Stb. This "stacking process" is a process for forming a recess on one side, e.g., under side of each of a plurality of flat plates and a protrusion on the other side, e.g., upper side of each of the plates, when the plates are stamped, and then stacking the plates one on the other with each protrusion press-fitted into each recess mating with the protrusion to form a plurality of stacked portions on the plates.
According to the above process, however, if a columnar inner core having a diameter of e.g., 8 mm, is formed by the above process, the width of the outermost plate will be as small as 2 mm, as can be seen in FIG. 13. Therefore, if a plurality of steel plates are connected one another by the stacking process, the diameter of the stacked portion will be small in diameter to have a connecting strength of smaller than 2 kgf, so that the stacked plates will be easily peeled off. In the case where the columnar inner core is produced, the wider steel plate is stacked on the narrower steel plate in sequence to broaden the width of the stacked plates gradually, and then the narrower steel plate is stacked on the wider steel plate in sequence to narrow the width of the stacked plates gradually. In this case, however, if the wider steel plate is stacked on the narrower steel plate, the staked plates will be likely bent along the longitudinal direction, so that the stacking process will be difficult. As a result, a stamping process using a progressive die can not be employed, so that the productivity will be reduced and the manufacturing cost will be raised.

Ignition coil for an internal combustion engine


An iron type golf club head including a bottom sole having a first level support surface at a first angle relative to the ball striking face, a second level support surface at a second angle relative to the ball striking face, and a third level support surface offset laterally from the first and second levels at a third angle relative to the ball striking face.

The present invention relates to wedge type golf clubs and, in particular, to a wedge club having three distinctive ground engaging surfaces.
The rules of golf require that no more than fourteen golf clubs be used in the playing of a round of golf. This requires a golfer to select particular golf clubs in order to execute the shots anticipated during the playing of a particular round. Normally a golfer will use a putter and at least two wood or metalwood type golf clubs for longer tee and fairway shots. This leaves ten or eleven iron type golf clubs which are then used to complete the fourteen club set. Currently there are a number of wedge type golf clubs available with various lofts ranging from a 52.degree. angle up to and including as high as a 65.degree. angle. Most manufacturers provide a range of four to five wedge type golf clubs, each having different loft and club head configurations to satisfy an individual golfer. Assuming a golfer uses a standard selection of irons, that is, for example, a three iron through a nine iron, a golfer may be limited to two and, at the most, three wedges in keeping withing the fourteen club limit. For golfers who prefer to use multiple wedges, often this results in a golfer not being able to use one or more of his wedge type golf clubs.
Normally the sole or bottom surface of a golf club is designed to lie flat on the ground surface to position the club face at a predetermined face loft angle. A golfer may manipulate the club face of a particular lofted club to alter the loft face angle, however this results in the sole of the club head being angled, that is not flat, with respect to the ground surface. To enable a golf club to be used for a number of different loft angles, golf clubs with multiple uses have been developed having a plurality of ground engaging surfaces, each with different angular configurations whereby a single golf club may functionally take the place of two or more golf clubs with different lofts. For example, U.S. Pat. No. 2,705,147 to Winter shows a wood type golf club head having a plurality of sole surfaces each having a different angle in order to adjust the loft angle of the golf club.
U.S. Pat. No. 5,549,296 to Gilbert shows a golf club having a three surface sole; a positive bounce sole, a trailing sole surface and a crescent surface between the two having a substantially straight front border and a crescent shaped curved rear border.
Another U.S. Pat. No. 5,800,281 to Gilbert shows a golf club sole configuration including three surfaces; an entrance surface, a bounce surface and a trailing surface. The sole also includes a first and second cavity located between the bounce surface and the toe and between the bounce surface and the heel.
U.S. Pat. No. 5,643,106 to Baird shows a golf club head with a sole having a double convex profile which defines separate convex bounce surfaces and a recessed channel disposed between the bounce surfaces.
U.S. Pat. No. 5,301,944 to Koehler shows a golf club head having a dual sole configuration wherein the leading edge has a positive bounce angle and the trailing edge also has a positive bounce angle which is less than the angle of the leading edge.
The present invention is directed to a high lofted, wedge type iron golf club head having an improved, multi-level sole configuration. The multi-level configuration includes three separate angular sole surfaces whereby the club may be placed flat on a ground supporting surface at one of three different loft angle positions such that a first sole surface corresponds to a lower lofted golf club, a second sole surface corresponds to an intermediate lofted golf club and a third sole surface corresponds to a higher lofted golf club. The first surface extends from the leading edge of the club head to approximately the midpoint on the sole in a front to rear direction. The second surface extends from the midpoint to the rear edge. The third surface is formed offset from the first two surfaces in a direction toward and adjacent to the heel. Each surface is formed at a different angle, thereby allowing the golf club to be placed on a support surface and used with a different loft angle permitting a golfer to hit a variety of shots with a single golf club.
Whereas, the angles of the three distinct ground engaging surfaces may take a wide variety of angular ranges, preferably the different levels correspond to the angular lofts normally found on wedge type golf clubs, including but not limited to pitching wedges, sand wedges and lob wedges. For example, the first surface may create a loft angle relative to the ball striking face corresponding to a normal loft angle of a pitching wedge. The second surface may create a loft angle relative to the ball striking face corresponding to a sand wedge. The third surface may create a loft angle relative to the ball striking face corresponding to a lob wedge.
Among the objects of the present invention is the provision of an iron type golf club head which may be used in a variety of loft configurations.
Another object of the present invention is the provision of a iron type golf club head which may be used as a pitching wedge, a sand wedge and a lob wedge.
Other objects and advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention.

Wedge type golf club tri-level sole configuration


A sheet punching device that cuts holes in a sheet while punches are entering die holes, in which a plurality of punch trains along each of which a plurality of punches are aligned on a rotating shaft in parallel with the rotating shaft are disposed in the rotation direction of the rotating shaft, and the die holes are disposed in correspondence with the punches of the punch trains.

1. Field of the Invention
The present invention relates to a sheet punching device for cutting a hole in a sheet, and an image forming apparatus, such as a copying machine, a printer, a facsimile machine, and a composite apparatus including the foregoing devices, provided with the sheet punching device.
2. Related Background Art
Up to now, a sheet punching device includes punches and dies of the number corresponding to the number of holes to be cut in a sheet and cuts the holes in the sheet while the punches are entering die holes, respectively.
However, the conventional sheet punching device is equipped with only the combination of the paired punches and dies of the same number as that of the holes to be cut in the sheet. For that reason, because the punches and the dies are quickly worn, the punches and the dies must be frequently replaced by new ones, resulting in a low efficiency of punching the sheet.
Also, because the number of holes to be cut in the sheet is different depending on the respective countries, if the conventional sheet punching device is adapted to a standard of some countries, it can not be adapted to a standard of other countries.
For example, in Japan, there are many cases in which two holes are cut in the sheet, and the sheet punching device that cuts two holes in the sheet cannot be adapted to such standard as of U.S.A. in which three holes are cut in the sheet.
Under the above circumstances, the operation of the sheet punching device is suspended and the punches and the dies must be replaced by new ones every time the number of holes is changed, thus degrading the punching efficiency.
Also, since an image forming apparatus with the conventional sheet punching device is low in the punching efficiency of the sheet punching device, the efficiency of forming an image on the sheet is low.

Sheet punching device and image forming apparatus having the same


A graphics display system is provided in which a graphics layer is printed upon a transparent substrate. An adhesive is generally applied over the graphics layer so that the graphics display system may be permanently affixed to a support. The graphics layer may be digitally printed upon the substrate using one or more UV-curable inks formulated to provide excellent adhesion to the substrate and resistance to degradation by the adhesive. The inks are capable of curing by UV radiation emitted from an LED array as opposed to conventional mercury vapor lamps.

1. Field of the Invention
The present invention is directed toward a graphics display system in which a graphics layer is printed upon a transparent substrate so that the graphics are visible therethrough. The inks used to create the graphics layer exhibit excellent adhesion to substrates, such as polycarbonate, and resist degradation by adhesives that might otherwise cause the graphics layer to delaminate from the substrate. In particular embodiments, the inks used to create the graphics layer are UV-curable digital inks capable of being printed onto the substrate by an inkjet printer.
2. Description of the Prior Art
Polycarbonate membrane displays are used in a variety of applications in many industries. Because of its durability, polycarbonate is a good material for use in high-performance environments. Moreover, because it is transparent, one can place an image on the underside, or sub-surface, of the polycarbonate sheet and the image will be protected against damage or wear. Polycarbonate membranes have been employed as overlays in the manufacture of membrane switches which are oftentimes required with withstand millions of switch activations over the product's lifetime. Polycarbonate membrane displays are also typically attached to a mounting surface through the use of a permanent adhesive. Because the image is printed on the sub-surface of the membrane, the ink comes into direct contact with the adhesive. If the adhesive and ink are not properly formulated to be compatible with each other, the adhesive can re-wet the ink thereby resulting in delamination of the ink, and adhesive, from the polycarbonate substrate.
Polycarbonate membrane displays have also been used in the construct of backlit displays, such as those found in automotive interiors. In a backlit display, certain portions of the polycarbonate membrane display are opaque or "blacked out" so that light is permitted to pass through only certain parts of the display. In order to deliver the required opacity, the inks printed upon the polycarbonate membrane must have a high solids and pigment levels. Therefore, such inks have typically been of the screen-printed variety.
Inkjet printing offers the capability to produce on-demand graphics of very high quality. However, until now, digital inks have not been able to provide the performance characteristics necessary to successfully print polycarbonate membrane displays. Presently available digital inks are susceptible to adhesive migration in which the solvents from the adhesive attack and re-wet the ink. This can lead to degradation of image quality over time and failure of the display due to ink delamination. Furthermore, because digital inks are fired through very small nozzles in the inkjet head, it is very difficult to construct an ink having sufficient opacity for use in polycarbonate membrane displays.
In some applications for polycarbonate membrane displays, the membrane may need to be thermally formed into a desired shape, or embossed. Therefore, inks that are highly crosslinked will not stretch or elongate during thermal processing or embossing thereby resulting in the degradation of the graphic's quality.
Accordingly, there is a need in the art for an ink system that can be digitally printed onto a transparent substrate for use in graphics display systems that exhibit excellent adhesion to the substrate, resist adhesive migration, and are capable of elongation along with the substrate during thermal processing.

LED curable ink system for multi colored sub-surface applications

Donald D. Sloan, Trustee of the Donald D. Sloan Trust


Systems and methods for automated patient anatomy and orientation identification using an artificial intelligence (AI) based deep learning module are provided. The method comprises positioning a subject over a table of a magnetic resonance imaging (MRI) system and wrapping at least one radiofrequency (RF) imaging coil over the subject. The method comprises obtaining a plurality of depth images, color images and infrared images of the subject using a three-dimensional (3D) depth camera and identifying the table boundary of the MRI system using the images obtained by the 3D camera. The method further comprises identifying a location of the subject over the table to determine if the subject is positioned within the table boundary of the MRI system and identifying a plurality of key anatomical points or regions corresponding to a plurality of organs of the subject body. The method further comprises identifying all DICOM orientations of the subject over the table of the MRI system and identifying the coils of the MRI system wrapped around the subject body and determining the orientation of the subject with respect to the coils of the MRI system, hospital gown, and blankets. The method further comprises identifying the anatomical key points occluded by the coils of the MRI system, hospital gown, and blankets to determine accurate positioning of the coils of the MRI system over the subject anatomy for automated landmarking of anatomies and imaging.

Various medical imaging systems and methods are used to obtain the images of the affected regions of the subject anatomy for diagnosing the medical conditions. Magnetic resonance imaging (MRI) is a known medical imaging technique used for imaging the different body parts like head, chest, abdomen and legs of a subject. MR imaging involves positioning the subject on a table of the patient positioning system of the MRI device and moving the patient positioning system inside the gantry of the MRI device for imaging. The MRI systems may contain a variety of imaging radiofrequency (RF) coils, for example a whole-body radiofrequency coil may be adapted to transmit the waveform towards the subject and configured to receive the waves from the subject to acquire the image data from the subject.
Although the images produced by the MR imaging techniques are of good quality, many images are adversely affected by the operational conditions of the MRI system and the subject movement. Movement of the subject, wrong positioning of the subject on patient positioning system, wrong positioning of the imaging coil over the subject may result in faulty images being obtained by the MRI system. Such images might be rejected by the radiologist and reimaging of the subject becomes necessary for obtaining the high-quality user viewable images. Precious time for treating the subject in serious medical conditions like trauma may be lost due to such imaging errors resulting in worsening the subject health conditions. Therefore, to avoid rejection of the MR images, it is very critical to accurately implement the imaging technique.
A skilled operator is required for accurate imaging of the subject using the MRI devices. Any error on part of the operator would result in an image containing an excessive disturbance or noise. Therefore, training of the operator and her experience in handling the MR imaging devices will affect the MR image quality. The operator may be skilled in acquiring the good quality images of the certain portion of the body due to her experience in obtaining the images of that body portion, but the operator may not be skilled to obtain the high-quality images of the entire subject body. This may be due to the lack of the imaging experience or lack of the anatomical knowledge of the entire body. Also, placing the MR imaging coils at the appropriate body portion affects the quality of the image. Physical parameters of the subject body like obesity, bone density, height, chest or abdominal size will create a challenging situation for the operator to correctly position the MR imaging coil for obtaining the complete image of the region of interest. Any wrong placement of the MR imaging coil would result in poor image quality and rejection of images of the regions of interest.
A study conducted by Little, Kevin J. et al. titled "Unified database for rejected images analysis across multiple vendors in radiography" in the Journal of the American college of Radiology 14.2 (2017); 208-2016 cites major reasons of the image rejection. These rejection reasons may include an incorrect positioning of the subject over the patient positioning system, incorrect use of the imaging technique by the operator, movement of the subject, imaging artifacts and others. The study further indicates that amongst the rejected images for different body organs and systems, the rejection percentage of the images of the chest, abdomen, pelvis and spine region was higher than the other body organs.
Majority of the pre-scan errors in the MRI radiological workflows are due to in-appropriate positioning of the subject, incorrect imaging protocol followed by the operator of the MRI system for the anatomy to be scanned and negligence of the operator/technologist. The operator/technologist who is responsible for scanning the subject may commit pre-scan errors such as scanning the subject with incorrect subject orientation, scanning the subject with inappropriate pose, angle, and direction. Further, when the subject checks-in the scanner room with a prescription of the body part to be scanned, the operator reviews the prescription, and then prepares the patient for the scan. During this process, pre-scan errors may be committed due to for example the operator mis-interpreting the prescription and instructing the subject towards an in-appropriate pose and orientation. The subject may mis-interpret the instructions given by the operator, leading to an inappropriate pose and orientation. In another example, the operator may not pay attention to incorrect pose and orientation of the subject and completes the scan.
All these pre-scan errors may lead to rejection and repetition of the scans. This causes discomfort to the subject, increases the subject wait time and the cognitive stress on the operator and the radiologists, and further reduces the throughput of the scanner machine. Further, the operator/radiologist must manually select the appropriate imaging protocol for scanning the subject based on the positioning and orientation/pose. This is always error prone, because if the operator/technologist is not alert enough to pull the correct protocol, they end up scanning the patient with a wrong protocol or an incorrect posture.
Therefore, systems and methods are required for providing an automated guidance to the scanning personnel to appropriately position the subject on the table of the MRI system, set the scan parameters, use the appropriate imaging coils of the MRI system and scan the regions of the subject to generate the high quality MR images with minimum errors.

Deep learning based methods and systems for automated subject anatomy and orientation identification


A measure control delay includes a measuring delay line and a signal generating delay line, each of which include a plurality of series-connected delay units. A digital signal is applied to an initial delay unit in the measuring delay line and it sequentially propagates through the delay units until a second digital signal is received. These outputs are applied to control inputs to the signal generating delay line to control the number of delay units through which a clock signal propagates before being output from a final delay unit. Each of the delay units in the measuring delay line includes a pair of series connected NOR gates. A NOR gate to which the digital signal is initially applied is coupled to a second NOR gate as a flip-flop so that the output of the NOR gate remains constant after the digital signal has been applied to the measuring delay line.

Periodic digital signals are commonly used in a variety of electronic devices. Probably the most common type of periodic digital signals are clock signals that are typically used to establish the timing of a digital signal or the timing at which an operation is performed on a digital signal. For example, in synchronous integrated circuits, the integrated circuit is clocked by an external clock signal and it performs operations at predetermined times relative the rising and falling edges of the applied clock signal. Examples of synchronous integrated circuits include synchronous memory devices such as synchronous dynamic random access memories (SDRAMs), synchronous static random access memories (SSRAMs), and packetized memories like SLDRAMs and RDRAMs, and include other types of integrated circuits as well, such as microprocessors.
The timing of signals external to a synchronous memory device is determined by the external clock signal, and operations within the memory device typically must be synchronized to external operations. For example, commands and addresses are placed on respective command and address buses of the memory device in synchronism with the external clock signal, and the memory device uses the external clock signal to latch these commands and addresses at the proper times to successfully capture the commands and addresses. Similarly, write data are applied to a data bus in synchronism with a write data strobe signal, and the memory device uses the write data strobe signal to latch the write data at the proper time.
Internal circuitry in a memory device through which the external clock and strobe signals are coupled necessarily introduces some time delay, causing the clock and strobe signals to be phase shifted by the time they reach respective latches. As long as the phase-shift is minimal relative to the timing margins of the memory device, the external clock and strobe signals can capture the commands, addresses and data at the proper time. However, as the operating speeds of memory devices have continued to increase, the "eyes" during which the commands, addresses and data must be captured have become increasingly smaller, thus making the timing of the clock and strobe signals even more critical. As a result, the time delays introduced by internal circuitry have become more significant.
To latch the applied commands, addresses, and write data at higher operating speeds, internal clock and strobe signals are developed in synchronism with the external clock and strobe signal, respectively. The internal clock signal is applied to latches contained in the memory device to thereby clock the commands and addresses into the latches during an "eye" in which the commands and addresses are valid. Similarly, the internal write data strobe signal is used to capture the write data in a latch at the proper time to ensure that a transition of the internal write data strobe signal occurs during an "eye" in which the write data are valid. A similar technique is often used in a memory controller coupled to a synchronous memory device. In such case, the memory device transmits read data and a read data strobe to the memory controller. The memory controller uses an internal read data strobe signal synchronized to the external read data strobe signal to capture the read data during the "eye" when the read data are valid.
A number of different approaches have been considered and utilized to generate internal clock and strobe signals that are synchronized to external clock and strobe signals, respectively. For example, delay-locked loops (DLLs), phased-locked loops (PLLs), measure controlled delays (MCDs), and synchronous mirror delays ("SMDs") have been used, as will be appreciated by those skilled in the art. FIG. 1 is a functional block diagram of a conventional MCD 100 that receives an applied clock signal CLK and generates a clock signal CLKSYNC that is synchronized with the CLK signal. The MCD 100 includes an input buffer 102 that receives the CLK and generates a buffered clock signal CLKBUF in response to the CLK signal. The CLKBUF signal has a delay D1 relative to the CLK signal, where D1 corresponds to the inherent propagation delay of the input buffer.
A model delay line 104 receives the CLKBUF signal and generates a forward delay clock signal FDCLK having a model delay D1+D2 relative to the CLKBUF signal. The model delays D1 and D2 simulate the delay D1 introduced by the input buffer 102 and a delay D2 introduced by an output buffer 106 that generates the CLKSYNC signal, as will be explained in more detail below. The FDCLK signal propagates through a measuring delay line 108 including a plurality of delay units 110A-N coupled in series, each delay unit 11-A-N receiving an input signal from the prior delay unit generates an output signal having a delay UD relative to the input signal. Each delay unit 110A-N may, for example, be an AND gate having one input enabled as indicated for the delay unit 11A, with the inverter introducing the delay unit UD corresponding to the propagation delay of the inverter. In the measuring delay line 108, the FDCLK signal propagates through the delay units 110A-N from left to right in FIG. 1, as indicated by the orientation of the inverter in the delay unit 110A. Each of the delay units 110A-N generates a corresponding control signal on lines 112A-N, respectively. As the FDCLK signal propagates through the delay units 110A-N, a control signal at the corresponding output 112 A-N changes state.
A signal generating delay line 114 includes a plurality of delay units 116A-N coupled in series as previously described for the measuring delay line 108. Instead of providing the outputs from the delay units 116A-N as with the measuring delay line 108, however, the signal generating delay line 114 has a plurality of inputs 118A-N to the corresponding delay unit 116A-N, respectively. Once again, each delay unit 116A-N may be formed by an AND gate. A controller 120 receiving the CLKBUF signal is coupled to receive the control signals on lines 112A-N of the measuring delay line 108. The controller 120 then outputs the CLKBUF signal on one of the inputs 118A-N of the delay units 116A-N in the signal generating delay line 114. The controller 120 uses the control signals from the measuring delay line 108 to determine the delay units 110A-N through which the rising edge of the FDCLK signal propagated by the time the next rising edge of the CLKBUF signal is received. The controller 120 then applies the CLKBUF signal to the input 118A-N of the delay unit 116A-N in the signal generating delay line 114 that corresponds to the delay unit 110A-N in the measuring delay line 108 to which the FDCLK signal had propagated. For example, if the rising edge of the FDCLK signal has propagated to the output of the delay unit 110J by the time the next rising edge of the CLKBUF signal is received, the controller 120 applies the CLKBUF signal to the input of the delay unit 116J in the signal generating delay line 114. The CLKBUF signal then propagates through the corresponding delay unit 116J in the signal generating delay line 114 and through all delay units 116I-A to the left of that delay unit, and is output from the signal generating delay line 114 as a delayed clock signal CLKDEL. The output buffer 106 receives the CLKDEL signal and generates the CLKSYNC in response to the CLKDEL signal, with the CLKSYNC being delayed by the delay D2 introduced by the output buffer.
The overall operation of the MCD 100 in synchronizing the CLKSYNC signal with the CLK signal will now be described in more detail with reference to FIG. 1 and a signal timing diagram of FIG. 2 illustrating various signals generated by the MCD during operation. In the example of FIG. 2, an initial rising-edge of the CLK signal occurs at time T0. In response to the rising-edge of the CLK signal at the time T0, the input buffer 102 drives the CLKBUF signal high with a delay D1 at time T1. This initial rising-edge of the CLKBUF signal is designated in FIG. 2 the N edge of the CLKBUF signal. In response to the rising-edge transition of the CLKBUF signal at the time T1, the model delay line 104 drives the FDCLK signal high after a model delay D1+D2 at time T2. The FDCLK signal thereafter propagates through the delay units 110A-N in the measuring delay line 108 until a next rising-edge N+1 of the CLKBUF signal is applied to the measuring delay line 108 at a time T3. At the time T3, the measuring delay line 108 has delayed the FDCLK signal by a delay FD that equals TCK−(D1+D2) where TCK is the period of the CLK signal. This is true because, as illustrated in FIG. 2, the next rising-edge of the CLKBUF signal occurs TCK−(D1+D2) after the initial rising-edge of the FDCLK signal at the time T2.
In response to the rising-edge of the CLKBUF signal at the time T3, the controller 120 applies the CLKBUF signal to the input of the delay unit 116A-N in the signal generating delay line that corresponds to the delay unit 10A-N to which the FDCLK signal had propagated when the rising edge of the CLKBUF signal was received. For example, assume that the delay TCK−(D1+D2) equals eleven delay units UD so that the controller 120 receives the control signal from the output 112K of the delay unit 110K in the measuring delay line 108. In this situation, the controller 120 applies the CLKBUF signal to the input 118K of the delay unit 116K in the signal generating delay line 114. This is illustrated in FIG. 2 as a rising-edge of the CLKBUF signal at the time T3.
The CLKBUF thereafter propagates through the appropriate delay units 116J-A in the signal generating delay line 114, and at a time T4 the signal generating delay line 114 drives the CLKDEL signal high in response to the applied output signal. At the time T4, the signal generating delay line 114 has delayed the CLKBUF by a delay that equals TCK−(D1+D2) which equals the delay FD of the measuring delay line 108. This is true because the CLKBUF signal propagates through the same number of delay units 116A-N in the signal generating delay line 114 as did the FDCLK signal propagate through the delay units 10A-N in the measuring delay line 108, as will be appreciated by those skilled in the art. The total delay of the CLKDEL signal at the time T4 equals D1+D1+D2+TCK−(D1+D2)+TCK−(D1+D2), which equals 2TCK−D2. Thus, the rising-edge of the CLKDEL signal at the time T4 occurs the delay D2 of the output buffer 106 before a next rising-edge of the CLK signal at a time T5. In response to the CLKDEL signal at the time T4, the output buffer 106 drives the CLKSYNC signal high at the time T5 and in synchronism with the rising-edge of the CLK signal. In this way, the MCD 100 generates the CLKSYNC signal having rising-edges that are synchronized with the rising-edges of the CLK signal.
In the MCD 100, although the input buffer 102 and output buffer 106 are illustrated as single components, each represents all components and the associated delays between the input and output of the MCD 100. The input buffer 106 thus represents the delay D1 of all components between an input that receives the CLK signal and the input to the model delay line 104, and the output buffer 106 represents the delay D2 of all components between the output of the signal generating delay line 114 and an output at which the CLKSYNC signal is developed, as will be appreciated by those skilled in the art.
As explained above, the controller 120 performs the function of applying the CLKBUF signal to one of the inputs 118A_N of the corresponding delay unit 116A-N in the signal generating delay line 114. As mentioned above, the controller 120 generally performs this function by detecting which delay units 110A-N in the measuring delay line 108 are outputting a high logic level when the next rising edge of the CLKBUF signal occurs. However, if the FDCLK signal simply propagated through the delay units 110A-N, the first half of the delay units 110A-N would be outputting a low logic level and the second half of the delay units 110A-N would be outputting a high logic level on the occurrence of the next rising edge of the CLKBUF signal. The mix of high and low logic levels from the delay units 110A-N would be even more complicated if, as in some MCDs, several periods of the FDCLK signal are allowed to propagate through the measuring delay line 108.
The mix of high and low logic levels that the controller 120 receives from the measuring delay line 108 can make it difficult for the controller 120 to perform its function of applying the CLKBUF signal to the correct delay unit 116A-N in the signal generating delay line 114. For this reason, MCDs typically include a control circuit (not shown) inserted between the model delay line 104 and the measuring delay line 108 for maintaining the FDCLK signal high responsive to the rising edge of the FDCLK signal. As a result, all of the delay units 110A-N through which the rising edge of the FDCLK signal propagates will output a high regardless of how many periods of the FDCLK signal have occurred during such time. Unfortunately, these control circuits inevitably delay the signal applied to the measuring delay line 108 responsive to the rising edge of the FDCLK signal. At higher operating speeds, these delays must be compensated for with a delay model, but such delay models do not always provide adequate compensation particularly in the presence of temperature, process and supply voltage variations.
The results achieved with the above-described control circuits, i.e., ensuring that all of the delay units 110A-N through which the rising edge of the FDCLK signal propagates output a high, could be achieved without using a control circuit by making the measuring delay line responsive to the falling edge of the CLKBUF signal. However, this approach would provide accurate results only if the falling edge of the FDCLK signal occurs after one-half period of the FDCLK signal. Unfortunately, external clock and strobe signals often do not have a 50% duty cycle. Therefore, this approach cannot be used in many cases.
There is therefore a need for an MCD having a measuring delay line that, for the entire period of an input signal, outputs high logic levels from all delay units 110A-N through which a transition of an input signal propagates without passing the input signal through a control circuit that introduces undesirable delays to the input signal.

Measure control delay and method having latching circuit integral with delay circuit


A local area network system is provided in which a plurality of communications nodes (14 and 16) are operable to transmit and receive information across a plurality of communications links (10 and 12). A plurality of redundant adapters (18 and 20) are coupled between the communications links (10 and 12) and the communications nodes (14 and 16), such that the communications nodes (14 and 16) are capable of transmitting and receiving information across each of the communications links (10 and 12).

Local area network systems, such as Ethernet systems, have become popular in both office and industrial environments. Such systems use bus structured architectures which allow a plurality of nodes to communicate across the area network. The communications are transmitted across such cables as coaxial, fiber optic and shielded twisted-pair.
Because of the critical nature of communication between devices in certain applications, such as in the process industry, it is often necessary to provide redundant communications media to insure communications in the event that one communication path fails. In systems such as Ethernet systems, redundant communication paths are feasible only if all communications nodes contain at least one Ethernet controller for each communication path, and if the nodes have routing capability. Routing capability is a protocol which requires each node to make decisions about which path to use for communication with an adjacent node. In existing systems, not all nodes are capable of routing, and many do not support multiple Ethernet interfaces.
Therefore, a need has arisen for a method and apparatus that allows devices without routing capability and those without sufficient communication controllers to be adapted to communicate over redundant paths.

Method and apparatus for redundant local area network systems


The present invention is directed to an amplifier, which is able to re-configure its internal protection circuits based on an output signal level. This allows the amplifier to apply the best protection level to the present operational condition. The protection level or threshold for protecting the amplifier is dynamically adjusted to a lower threshold level, thereby making it more sensitive in certain operating scenarios. In one embodiment of the present invention, a first current protection threshold is used to operate an amplifier in a first state. If an event occurs, the amplifier protection circuit is re-configured and the amplifier continues to operate with a second protection threshold in a second state.

1. Field of the Invention
The present invention relates to a protection circuit for an amplification device.
2. Background of the Invention
Typically, amplifiers use a constant protection level or "threshold". When the threshold is exceeded a protection circuit is invoked, which shuts down the amplifier or otherwise causes it to protect itself from permanent damage. The protection threshold needs to be placed outside the extreme limit of operation of the amplifier to prevent its unintentional activation during normal usage.
The problem with currently available protection techniques is that fault conditions also occur in scenarios where the protection threshold is not exceeded. One such scenario is when the system is driving a short, during low output levels. Under conditions when the output voltage is high, the modulation level of the amplifier is also high. In this case, the system runs efficiently, so a large input current being carried through the system is not a problem. Under conditions when the output voltage is low, the modulation level of the amplifier is also low. In this case, the system runs inefficiently, so a large current being carried through the system may be a problem.
A short circuit condition, when it occurs at a time when the output voltage is high, is typically not a problem because the system can handle a high current surge when it is running efficiently and it will shut down, because in this condition, prior art current protection thresholds are designed to shut the amplifier off.
However, a short circuit condition, when it occurs at a time when the output voltage is low, may be a problem. When the output voltage is low, the output modulation level is also low. This causes the system to run inefficiently. Moreover, during this condition the current will not be high enough to reach prior art protection thresholds, so the system will not shut down. Since the system is running inefficiently in the latter short circuit condition and will not shut down, and at the same time sourcing a high current, the system components overheat, and/or become damaged.
In many of these cases the eventual destruction of the amplifier will occur due to excess power dissipation in the amplifier output section. For example, if the speaker output is shorted during a low output level or low volume, the amplifier might not reach its protection level and never invoke the protection circuit.
Therefore, the amplifier will continue to operate in this fault condition, which may cause excessive power dissipation within the amplifier and its failure, despite having a protection circuit with a protection threshold in place.

Re-configurable amplifier protection apparatus and method


Intelligent mobile agents in a distributed network carry information tokens among network nodes. Each token includes compressed information or data, and an indication of the compression algorithm which can decompress the information. At least some of the nodes have at least one decompression algorithm. A copy of a token may be left at a node by an intelligent mobile agent moving through the network. A later-arriving intelligent mobile agent can interrogate the node to determine what information it has in the form of tokens, and can use the token information, or take the token (or a copy) elsewhere.

Distributed communication systems or networks are now widely used. Such communications systems may be widely distributed information sources such as local- or wide-area networks, corporate or military communication systems, or the world-wide computerized interactive communication system known as the internet. Such communication systems can be used to access remote information or computing resources. When using such systems, it is necessary to know the location or address of the information being sought or of the computing resource to be used, or the user must carry out a search procedure to locate the information. In the case of very large distributed systems which are not indexed, the search is so extensive or time-consuming that it may be impractical, and may therefore not be attempted.
There has been interest in the use of intelligent mobile agents for overcoming some of the problems associated with searches of distributed, possibly unindexed, data bases or computing resources. An intelligent mobile agent is a computer program which can independently or semi-independently perform tasks which the operator could not perform on his own because of the time or effort required for the task. For example, an intelligent mobile agent might be used to discover information autonomously, or under its own control, because the operator or user of the distributed communication system might not be aware of the existence of a source of useful information, or of its address if its existence were known. The mobile intelligent agent is a computer-type program characterized by the ability to move over the communication system from one computer to another while the program is "running"; in fact, it is necessary for it to do so in order to perform its tasks. This does not, of course, mean that the bit pattern of the program changes while it is in transit from one computer to the other, but rather means that, in performing its tasks or "running," the program moves its location from one computer to another. Intelligent mobile agents or "softbots" are described in the following references:
1) "Intelligent Agents: The First Harvest of Softbots Looks Promising", Sara Reese Hedberg, IEEE Expert. PA0 2) "Harnessing the World Wide Web", Jay Allen Sears, US Advanced Research Projects Agency, IEEE Expert. PA0 3) "Intelligent Agents on the Internet: Fact, Fiction, and Forecast", Oren Etzioni and Daniel S. Weld, University of Washington, IEEE Expert. PA0 4) "AI on the WWW--Supply and Demand Agents", Carol Brown, Oregon State University; Les Gasser and Daniel E. O'Leary, University of Southern California; Alan Sangster, University of Aberdeen, IEEE Expert. PA0 5) "Telescript Technology: Mobile Agents", James E. White, General Magic, Inc., American Association for Artificial Intelligence.
One problem which has been found with the use of such mobile agents for seeking information on a distributed computing or knowledge base is that the capability of the agent is more or less related to the size or complexity of the program which embodies the intelligent mobile agent, so that a highly capable mobile agent, just like a highly capable computer program of any sort, tends to be very large in terms of the number of bytes which it contains. Thus, autonomous agents which maintain their state over time, and which are not totally "scripted" and therefore are knowledge-based or "learning" programs, as are the domains of knowledge about which they maintain an understanding, tend to be quite large. The length of time required to transmit the intelligent mobile agent from one computer to another (from one "site" or network "node" to another) over the communication system depends upon the bandwidth of the system in bits or bytes per second. It may not be practical to use a highly capable intelligent mobile agent, because the large size of such an agent requires excessive computer-to-computer transmission time. If the bandwidth of the distributed communication system can be controlled, then its bandwidth can simply be expanded in order to accommodate the desired mobile agents at the desired speed. Ordinarily, the communication system or data base is a given, and its bandwidth cannot be controlled. It should be noted here that limitations in the bandwidth of a part of a computer which interacts at a network node with the communication system will have the same effect, as to that computer, as a limitation of the bandwidth of the communication system itself; it is therefore desirable to use the highest possible speed modem at each computer site. Under bandwidth-limited conditions, the use of a highly capable intelligent mobile agent may result in excessive transmission time delays, and these directly impact the time required for the intelligent mobile agent to perform a search. The amount of time which is considered to be excessive may depend upon the information sought and its importance. If search time is irrelevant, a highly capable intelligent mobile agent may be used on a low-bandwidth distributed computing system or network. Ordinarily, however, large transmission times are undesirable because of the resulting delays in receiving the search results, especially in those cases in which real-time information is sought. Thus, if a very complex search is required to find the desired information, a highly capable intelligent mobile agent capable of performing the search may be too large to be practical under given circumstances. The inability to quickly transmit highly capable intelligent mobile agents tends to prevent full utilization of the resources of the communication system.
U.S. patent application Ser. No. 08/741,759, filed Nov. 5, 1996 in the name of Whitebread et al., describes a scheme for improving the resource utilization in limited bandwidth communication systems. As described generally therein, a distributed communication network includes a plurality of computers, and communication paths for coupling the computers together at nodes of the network for communications therebetween. The network also includes standardized computer network software associated with each of the computers, for providing basic network communications between or among the computers; this may be software suitable for use with a world-wide communication system commonly known as "internet." The network according as described in the Whitebread et al. application also includes a mobile agent generating program located at one or more of the computers of the network, for generating, and for transmitting over the communication network to at least one other computer of the network, agents for performing a desired function. The dimensions (size) of a mobile agent are related to its capability, whereby highly capable agents may be so large as not to be usable, because of network bandwidth limitations. A mobile agent docking arrangement is located at each computer or node of the network, which capability expander is capable of coacting with the mobile agents, for rendering the agents active at that computer. A mobile agent capability expander is located at, or associated with, at least one of the computers of the network which is capable of coacting with mobile agents, for extending at least one capability of a mobile agent. This enhances the capability of mobile agents used in the system without expanding limited network bandwidth. The information embodying the capability enhancement or expander may be transmitted over the communication network to the agent-receiving computer(s) at infrequent intervals, during which the communication network is otherwise lightly loaded, so that the capability expander is available at such later time at which a mobile agent arrives. The capability enhancement may instead be uploaded to the agent-receiving computer(s) from a portable memory, such as a floppy disk.
FIG. 1 illustrates a communication system designated generally as 10, which includes a network 12 and four representative network nodes with computers 14a, 14b, 14c, and 14d connected to the network, as described in the abovementioned Whitebread patent application. As mentioned above, each computer is capable of sending intelligent mobile agents out to any of the other three computers. Such mobile agents can be generated at each of computers 14 by the use of a language such as agent TCL, available from the computer science division of Dartmouth College, Dartmouth, N.H., and the mobile agent can be transmitted, by way of the network 12, to the other computers after its generation. The bandwidth of a network such as network 12 varies from about 4800 baud or bits-per-second to as much as tens of megabaud, and may vary within the network, depending upon which network branch is considered.
FIG. 2 is a simplified block diagram of an arrangement which is similar to a portion of the arrangement of FIG. 1. In FIG. 2, a source of intelligent mobile agents is illustrated as 14a, which is the same designation as that of computer 14a of FIG. 1. Element 14a of FIG. 2 is designated as a "source", because in the most basic system, it needs only to transmit or launch a mobile agent; it may, of course, have other capabilities. The active agent goes out onto the network from element 14a of FIG. 2, and performs its tasks, moving from computer to computer as necessary. If the mobile agent is programmed to return to source 14a when its task is completed, then source 14a must also be capable of receiving the information conveyed by the mobile agent. While source/sink 14a of FIG. 2 need not be a computer, it will ordinarily be such.
Also in FIG. 2, network 12 is connected to a second "computer" block 14b, which may include a database 210 and an agent dock 212. Database 210 may be simply a memory which can be accessed by an intelligent mobile agent, in which case block 14b must further include a processor or "computer", because the intelligent mobile agent must reside, at least temporarily, at location 14b. Instead of a database such as 210, agent dock 212 could be coupled to any other data or computing resource which is to be acted upon by an intelligent mobile agent. As also illustrated in FIG. 2, database 210 is coupled to agent dock 212, and the network 12 is also connected to agent dock 212.
The intelligent mobile agent is a program. In an ordinary computer system, blocks 210 and 212 of location 14b of FIG. 2 may be hardware, or they may be programs (software) which are resident at location 14b. Agent dock 212 of FIG. 2 has the ability to interface or interact with the intelligent mobile agent, and also provides the intelligent mobile agent with capabilities which reside at location 14b. Such capabilities might include access to knowledge bases, additional computational functions, and the like.
FIG. 3 is a simplified architecture diagram which represents the software in the agent dock 212 of FIG. 2. In FIG. 3, one or more intelligent mobile agents 310a, . . . , 310n appears at a layer 310 at the bottom of block 212, adjacent to the path 214 by which it (they) arrive at the dock. It should be recognized that at any particular time, the agent dock may have no mobile intelligent agents docked therewith, it may have only one, or it may have two or more. When docked, each mobile agent 310a, . . . , 310n interfaces with a docking software layer 312, which recognizes the presence of the mobile agent, and which enables the mobile agent by effectively "pushing its ON button", to cause the intelligent mobile agent to recognize that it has arrived at a new location, and to enable it to execute its program or instructions. Location 14b also includes a knowledge base illustrated as 314.
Following the turn-on or enabling of the then-resident intelligent mobile agent 310a, . . . , 310n of FIG. 3, the docking layer 312 acts as a service provider to the intelligent mobile agent 310a, . . . , 310n. For example, the (or one of the) intelligent mobile agent(s) may indicate to the docking layer that the mobile agent is a search agent which is looking for particular data. Such data, in a military context, might be the presence, location, or identity, or all of this information, relating to electromagnetic radiators which might have been located by specialized equipment available at location 14b. It may happen that the computer at location 14b has no specialized equipment for generating the type of data which the intelligent mobile agent seeks, in which case the docking layer 312 of FIG. 3 so advises the agent 310a, . . . , 310n. In that event, the agent may go elsewhere in the network (to another computer location 14a, 14b, 14c, 14d, . . . ; of FIG. 1), or return to its source with a failure message. On the other hand, if the docking layer 312 knows that such information is available in its knowledge base 314, it advises the intelligent mobile agent 310a, . . . , 310n, of that fact, and of other relevant capabilities available. For example, in the context of an electromagnetic emitter locator, location 14b might have a database 316 containing raw data representing frequency and pulse characteristics of a received electromagnetic signal, and might also have an expert system 318 which is capable of evaluating the raw data, and which may have already evaluated the raw data, and have identified an emitter as being, for example, a weather radar operating at a particular physical location (which, in general, is not the same as a network location). On the other hand, location 14b might have the raw data represented by database 316, and the knowledge base required as the foundation for an expert system for identifying the emitter, but might not include the expert system itself.
In general, expert systems include two distinct portions, namely a knowledge base and a decision-making portion. The decision-making portion is typically much smaller than the knowledge base. However, the knowledge base changes from time to time as more information becomes available, and as conditions change. For example, in the medical fields the knowledge about the symptoms and progress of newly discovered diseases and/or conditions may not be in an older knowledge base, but, when such information is included in an updated knowledge base, the same types of decision-making programs can operate on the updated information in order to identify, and suggest treatment for, such newly discovered diseases and/or conditions. Similarly, in the abovementioned military application, the knowledge base 318d of FIG. 3 can be updated with the operating frequency, pulse characteristics, and other spectral characteristics of new radar and other emitter types as they become known, which the decision-making portion 318s of the expert system can then use to identify this new type of radar if the raw data is indicative of its presence. Layer portion 320 represents other capabilities which might be available to the intelligent mobile agent.
Thus, the docking layer 312 of FIG. 3 "tells" the then-resident mobile agent or agents of layer 310a, . . . , 310n, about the existence of the raw data available in database 316, and of the existence of either the knowledge base 318d of, or of the entire expert system 318, and also about any other available capabilities 320 which are relevant to the task which the intelligent mobile agent has identified.
Once the intelligent mobile agent 310a, . . . , 310n, of FIG. 3 has received information from the docking layer about the available capabilities, the intelligent mobile agent decides, based upon its program, which of the locally available capabilities it wishes to avail itself of. The docking layer facilitates obtaining the information from the raw-data database or the expert system, or from a stand-alone knowledge base, as required.
The information in expert system database 318 of FIG. 3 can be updated in any of a number of ways. For example, the database 318d can be updated by occasional transmissions over the network 12. While these transmissions may require substantial bandwidth, they are performed infrequently, and may be performed at low data rates, over extended intervals during low-traffic times. In the arrangement of FIG. 3, the expert system and a current database therefor are available to the intelligent mobile agent, without transmitting the entire expert system and its database each time an inquiry is made by transmission of an intelligent mobile agent. The knowledge base 318d may be updated by a memory upload provided by a maintenance worker from a memory disk, or from any other physical media.
FIG. 4 is a simplified flow chart illustrating the operation of a typical mobile agent 310a, . . . , 310n, as described in the abovementioned Whitebread patent application, and FIG. 5 is a simplified flow chart illustrating the operation of the docking system 312. The sequence of events begins with the arrival of a mobile agent at a network node (network site) or an agent dock, as suggested by block 410 of FIG. 4. The sequence representation then flows to a logic node 5-1, which represents a transfer of the sequence to a corresponding logic node 5-1 of FIG. 5. Logic block 510 represents a start point for the docking program, which starts up the logic, and then goes into a "wait" state, waiting for arrival of an agent at the node. From logic node 5-1 of FIG. 5, the logic flows to a block 512, which represents recognition by the logic flow of the docking system 312 that a mobile agent has arrived at the network node. The recognition represented by block 512 may be accompanied by a verification of a security code, following which the docking system logic flows to a decision block illustrated as 514. Decision block 514 decides whether the currently arrived agent has clearance to coact with this network node. If the mobile agent does not meet the security requirement, the logic leaves decision block 514 by the NO output, and flows to a block 518, which represents rejection of the mobile agent. The logic of the agent docking system then returns by a logic path 419 to block 512, whereupon the docking system continues to monitor for the appearance of an active agent at its network node.
If a mobile agent arrives at the network node and meets the established security criteria, the logic leaves decision block 514 of FIG. 5 by way of the YES output, and flows to a block 516, which represents a command for the starting of the mobile agent. From block 516, the logic flows by way of a logic node 4-2 to block 412 of FIG. 4. Block 412 of FIG. 4 represents the starting of the mobile agent in response to the command issued by logic block 516. From logic block 412, the logic flows to a decision block 414, which decides whether the mobile agent requires capability extension. This decision may be as simple as the examination of an "extension required" flag associated with the mobile agent. If no capability extension is required, the logic flows from decision block 414 by way of its NO output, and arrives at a block 416. Block 416 represents performance of the task assigned to the mobile agent by its internal programming. Once the task is completed, the logic flows from block 416 to a block 418. Since the mobile agent has completed its task, it must now decide whether it must return to the originating source with its data, or to seek more data by going on to a known further address, or search randomly by going to an address which has not yet been visited. Block 418 represents the decision as to where the mobile agent is to go next. From block 418, the logic flows to a block 420, which represents an instruction to the docking system to command the transmission of the mobile agent to the selected address. From logic block 420 of FIG. 4, the logic then flows by way of a logic node 5-3 to logic block 520 of FIG. 5, which represents acceptance of the direction to move the mobile agent to a defined network node. Block 522 represents the sending of the mobile agent to its next destination, and the logic then flows by way of a path 523 back to block 512.
In the event that the mobile agent requires extension of its capabilities, the logic flow is as described above until the logic arrives at decision block 414 of FIG. 4. In the case in which the mobile agent requires capability extension, the logic leaves decision block 414 by the YES output, and flows to a block 422, which represents making a request for a particular extension of capabilities from the docking system. It must be recognized that the network may have many nodes having different capabilities, and may have various kinds of mobile agents perambulating therethrough, seeking various different types of capabilities, not all of which are available at each network node. From block 422 of FIG. 4, the logic flows by way of a logic node 5-2 to a block 524 of FIG. 5. Block 524 represents the reception of a request for a particular type of extension capability. From block 524, the logic of the docking system flows to a decision block 526, which looks through its index of available capabilities to see if the requested capability is available. If the capability is not available at this particular network node, the logic leaves decision block 526 by the NO output, and flows to a block 528, which represents the sending of a "not available" signal to the mobile agent. From block 528 of FIG. 5, the control flows by way of a logic node 4-3 to decision block 424 of FIG. 4. Since the capability sought by the mobile agent is not available at this particular network node, the logic of the mobile agent leaves decision block 424 by the NO output, and flows to block 418. As described above, block 418 represents the determination of the location of the next network node to be visited by the mobile agent; from block 418, the logic passes through the states represented by logic blocks or nodes 420, 5-3, 520, and 522, back to block 512, which represents a "waiting for a mobile agent" state of the docking system.
As so far described, the cases which have been discussed in relation to FIGS. 4 and 5 are those in which (a) the mobile agent was not authorized to act, and was rejected; (b) was authorized to act, but did not require capability extension; (c) was authorized to act, and required capability extension, but the particular capability extension was not available at the network node or site. The next possibility is that the mobile agent arriving at the network node is authorized, requires capability, and the capability is available. In this last case, the logic will arrive at decision block 526 of FIG. 5 as described above, but, since the requested capability is available, the logic will leave by the YES output, rather than NO. From the YES output of decision block 526, the logic flows to a block 530, which represents the passing of a capability pointer to the requesting mobile agent. Logic node 4-3 returns the sequence flow to decision block 424 of FIG. 4, whereupon the logic leaves decision block 424 by the YES output, and flows to block 416, which as mentioned above represents the performance of the task, which presumably also means availing itself of the extended capabilities at the network node.
Thus, the arrangement described in the abovementioned Whitebread et al. application allows highly capable intelligent agents of relatively small size to be transmitted over limited-bandwidth networks for performing their functions, with the extended capabilities being made available at the appropriate remote network locations. Portable storage media may be used to take extended capability information to each computer remote computer. In some cases, it may instead be desirable to load the extended capability information into the computer by using the limited-bandwidth network, albeit at a data rate commensurate with network capabilities, by transmission over a period of time, preferably at a time when the network is lightly loaded.
FIG. 6 is a simplified block diagram illustrating three different arrangements for loading extended capability information into a computer at a remote location on the network so that it may be accessed by the docking system of that computer in response to the docking of a mobile agent. In FIG. 6, representative node 14d includes a medium reader, such as a floppy-disk reader 610, which is coupled to a capabilities repository, corresponding to the database, expert system, or the like of FIG. 3. Updates of the capability can be manually transported to the node on a data medium, illustrated as a floppy disk 612, and uploaded by means of the reader 610. Control could be accomplished manually by an operator at a remote site, with the delivery of the update information being performed over the network. It will be clear that updates over the network must be accomplished in the presence of sufficient security to guarantee that unwanted intrusion does not occur. The physical transmission by way of a data medium may also require security measures to assure that the knowledge base is not updated by someone having physical access but without authority to update. Another way to update the knowledge base is by a mobile agent, illustrated as Loader Agent 614, which is especially adapted for uploading or deliver of such information from a remote site during periods of low traffic on the network.
While it is very desirable to be able to express highly capable mobile agents at remote nodes, it is also advantageous to be able to use the cooperation of multiple intelligent mobile agents to perform various tasks. Cooperation of multiple agents implies the transfer of information between the agents. The bandwidth limitation of the communication network prevents the mobile agents from carrying large amounts of information. Improved methods of exchange of information between intelligent mobile agents is desired.

Information exchange by intelligent mobile agents in a network