A laser light output control apparatus is provided with first and second D/A converters, a current source for supplying a laser with a current, a monitor circuit for monitoring a laser light, a comparator for comparing output of the second D/A converter with output of the monitor circuit, and a microcomputer for setting values in the first and second D/A converters. A value to be given to the first D/A converter to set the laser light output at a specified value P1 and a value to be given to the first D/A converter to set the laser light output at another specified value P2 are both stored in the microcomputer. The laser light outputs of these specified values are obtained by using a feedback by the monitor circuit and the comparator. For light output between the specified values P1 and P2, an optional output value between the specified values P1 and P2 is set by calculating by the microcomputer a value to be given to the first D/A converter.

1. Field of the Invention
This invention relates to a laser light output control apparatus for a semiconductor laser.
2. Description of the Related Art
A semiconductor laser is used to obtain a laser light by energizing with a driving current IF through a p-n junction of a certain type. As shown in FIG. 5, the relation between the driving current IF and a light output intensity PO is not linear, but as the driving current IF increases, laser light oscillation starts at a certain current value Ith, and hereafter, the laser light output PO increases with increasing the driving current IF.
However, a threshold current Ith and the rate of change (differential efficiency .eta.) of PO relative to the change of IF are not constant, but vary with the ambient temperature and also with individual lasers in which laser light oscillation takes place.
FIG. 6 is a block diagram of a laser light output control apparatus conventionally used to drive a semiconductor laser with a constant light output intensity.
Reference numeral 10 denotes an up/down counter which counts up an output value in accordance with an input clock signal when an output of a comparator 17 is at "H" level and then an UP/DOWN signal of the up/down counter 10 is at "H" level, and counts down the output value in accordance with the input clock signal when they are at "L" level.
The output value of the up/down counter 10 is converted by a D/A converter 12 into a laser driving current IF, and supplied through a current source 13 to a semiconductor laser 14 to drive the semiconductor laser 14. The light output PO of the laser 14 is converted by a monitor circuit 15 into a voltage, which is compared with a set voltage VM by a comparator 17.
The comparator 17 outputs a "H" level signal when the voltage from the monitor circuit 15 is lower than the set voltage VM and a "L" level signal when the voltage from the monitor circuit 15 is higher than the set voltage VM.
As described, the conventional laser light output control apparatus with the component parts mentioned above constitutes a negative feedback loop of the comparator 17. When control of the laser light output is started, the up/down counter 10 counts up, the output value of the D/A converter 12 and the laser driving current IF continue to increase and the laser light output increases gradually. After the monitor voltage obtained by monitoring the laser light exceeds the set voltage VM, the counter 10 counts up and down repeatedly, so that the light output PO comes to settle almost at a fixed value regulated by the set voltage VM.
FIG. 7 is a timing chart in a case where a laser light output control apparatus such as shown in FIG. 6 is used.
At the rising edge of a clock pulse (a) in FIG. 7, a counted-up value is output to the D/A converter 12 from the up/down counter 10, and accordingly, the driving current IF changes stepwise as illustrated in FIG. 7(b). When the driving current IF exceeds the threshold current Ith, the laser 14 starts oscillation, and increases the light output PO as shown in FIG. 7(c). As PO reaches to a target level, the counter 10 counts up and down at about that corresponding level, and therefore, IF fluctuates about a certain value, so that PO comes settle almost at the target level.
When the light output is to be set to some other value in the apparatus mentioned above, it is necessary to change the set voltage VM and start with counter actions. However, since the counter actions are performed by feeding the laser light back through the monitor circuit 15 and the comparator 17, a long time is always required for setting the laser light output.


A phase/frequency detector, such as may be used in a phase-lock loop (PLL), having reduced jitter at high frequencies by reducing or eliminating the dead zone. The detector generates two output signals (UP and DOWN) wherein one of the output signals (depending upon which input signal arrives first) has a pulse width which is equal to a time delay between the input signals. There is a dead zone associated with very small phase differences between the input signals, and the dead zone is reduced by increasing the durations of two output pulses, using several delay elements which operate on signals that are derived from the reference and feedback inputs. The circuit may be tuned to reduce the dead zone to less than one picosecond, making it particularly useful for very high speed (greater than one gigahertz) clock circuits. The phase/frequency detector uses self-resetting, complementary metal-oxide semiconducting (SRCMOS) gates. First and second latches may be used to prevent the SRCMOS gates from discharging before a subsequent reset signal.

1. Field of the Invention
The present invention generally relates to electric clock circuits, and more particularly to a clock circuit that uses a phase-lock loop (PLL) circuit having a phase/frequency detector with reduced jitter at high frequencies.
2. Description of the Related Art
Electric circuits that provide clock signals are used in a wide assortment of electronic devices, and particularly in computer systems. Microprocessors and other computer components, such as random access memory (RAM), use clock signals to synchronize various high-speed operations. These computer clock circuits often use a phase-lock loop (PLL) circuit to de-skew (synchronize) an internal logic control clock to an external system clock.
A typical prior art PLL circuit includes a phase and frequency detector, a low-pass filter, and a voltage-controlled oscillator (VCO). The phase/frequency detector compares two input signals, a reference signal (from the external system clock) and a feedback signal, and generates a phase error signal that is a measure of their phase difference. The phase error signal from the detector is filtered by the low-pass filter and fed into the control input of the VCO. The VCO generates a periodic signal with a frequency which is controlled by the filtered phase error signal. The VCO output is coupled to the feedback input of the phase/frequency detector, thereby forming a feedback loop. If the frequency of the feedback signal is not equal to the frequency of the reference signal, the filtered phase error signal causes the VCO frequency to shift toward the frequency of the reference signal, until the VCO finally locks onto the frequency of the reference. The output of the VCO is then used as the synchronized (internal logic control) signal. The feedback loop may contain other components such as charge pumps, dividers, clock buffers or clock distribution networks. In cases where the incoming data is a self-clocking bit stream, the comparator system is used to extract the clock information from the data stream itself.
FIG. 1 illustrates a sequential phase/frequency detector (PFD) that is commonly used in PLLs. That PFD consists of four flip-flops and a four-input (reset) NAND gate, and has two outputs, up (U) and down (D). Each of these outputs can be in either a low voltage state or a high voltage state, and each has a duty ratio (d.sub.U and d.sub.D) which is the fractional amount of time that a given terminal is in the low state. The phase error signal used by the VCO is a function of these duty ratios (d.sub.U -d.sub.D). This particular PFD has several advantages, among them, aperiodicity and an active phase range of .+-.360.degree. (twice as large of many other PFDs), as noted in "Phaselock Techniques," F. Gardner, pp. 123-125 (1979).
Another conventional sequential phase/frequency detector is described in the article "A PLL Clock Generator with 5 to 110 MHz of Lock Range for Microprocessors," IEEE Journal of Solid-State Circuits, vol. 27, no. 1 (November 1992). That circuit is noted as being able to operate at very high frequencies (up to 400 MHz), since its critical path is limited by just three gate delays: two from cross-coupled, two-input NAND gates (in one of the two flip-flops), flops), band one from a four-input reset NAND gate. This PLL uses complementary metal-oxide semiconducting (CMOS) technology.
One problem with phase/frequency detectors is that jitter is introduced into the loop due to the "dead zone." The phase error signal that controls the VCO has a first polarity in the case where the reference signal has a phase lag, and the other polarity when a phase lead is detected. For very small phase differences (e.g., the zero-phase-error, steady-state condition of the locked PLL), in the transition from one polarity to the other there is often a region referred to as the dead zone where the phase error signal is insensitive to phase-difference changes. However, it is important that the control characteristic of the PLL be linear in a phase-difference interval that contains the zero-phase-error point, in order to avoid the VCO uncontrollably changing its phase. In this dead zone (or dead band) the VCO's eventual output signal is unpredictable and liable to dither. Several techniques have accordingly been devised to shrink the range of the dead zone.
One of these techniques is described in U.S. Pat. No. 5,546,052 which is very similar to the circuit of FIG. 1 except for the use of an additional NAND gate (reference numeral 110 of that patent). The reset path delay is increased to reduce the dead zone. The assertion time for all the outputs is extended, which ideally appears as a common-mode signal to the subsequent stages. Unavoidable layout and technology-dependent mismatches in the charge pump and large-area filter stages of the PLL significantly increase the error using such an approach, since the effect is not truly common-mode. Furthermore, the pulse width is extended by four gate delays using this approach (the interval over which the mismatch is integrated), greatly magnifying the error. This approach is generally thus not suitable for very high performance PLLs. See also U.S. Pat. No. 5,491,439.
Another of these techniques is described in U.S. Pat. No. 5,422,603. The dead-zone contribution of the charge pump filter is reduced by using a fully symmetric charge pump architecture, and by fully differential implementation of the loop filter. While this construction is an improvement over the above-noted patents, the pulse width is still determined by the reset path delay and is only coarsely adjustable. A similar design is disclosed in U.S. Pat. No. 5,436,596, in which the reset signal which keeps both the current sink and current source temporarily alive to avoid a dead zone region. A three-input AND gate driven by a signal divided down from the reference clock. The reference clock signal is added to reduce the effects of process, temperature and design features, but that invention also suffers from the same problems as the '603 invention.
In U.S. Pat. No. 4,804,928, a phase/frequency detector is disclosed which is configurable as either a phase or frequency detector. That circuit has the same rest path and delay dependence mentioned above. Unbalanced delays on the charge and discharge paths (reference numerals 16 and 18 of FIG. 1 of that patent) further aggravate the common-mode issues.
A generic phase detector with overlapping UP and DOWN outputs is included as part of the invention of U.S. Pat. No. 5,485,125. An asynchronous reset is available on this phase detector, and is asserted when overlapping outputs are detected, lowering the dead zone. The speed of the reset path (reference numerals 31 and 53 of FIG. 2 of that patent) limits the effectiveness of this approach, as in the other patents.
Yet another approach to minimizing jitter involves minimizing noise input to the VCO via the control voltage lines. See, e.g., U.S. Pat. No. 5,465,075. A plurality of power-down transistors are arranged in the control circuit, and the VCO circuit's gain may be selected at the minimum gain required to lock the PLL over a predetermined range of process and operating conditions. This approach does not address, however, reduction of the dead zone, and the foregoing issues still apply.
Another phase/frequency detector which is reminiscent of FIG. 1 is shown in U.S. Pat. No. 4,739,278, except that the NAND gates have been replaced with NOR gates. The reset gate is coupled to the latches such that additional gate delays are provided to ensure that the output signals of the discriminator reach the full logic amplitudes. The advantage of this adaptation is that the path dependence is reduced from the four-input NAND version of FIG. 1. The limitations of this approach regarding the dead zone are otherwise identical to the detector of FIG. 1.
Many of the foregoing approach to minimizing the dead zone are particularly complicated, and do not completely eliminate dead zone concerns. This is particularly true for high frequencies (greater than 1 GHz) since the dead zone problem becomes more pronounced due to circuit switching speed and rise time limitations (the circuits do not respond unless their switching thresholds have been exceeded). It would, therefore, be desirable and advantageous to devise a PLL clocking circuit having a phase/frequency detector which effectively eliminates jitters resulting from the dead zone at such high frequencies.

Self-resetting phase/frequency detector with reduced dead zone

International Business Machines Corporation


The invention relates to a sack cutting means (10) for offshore emptying of content from a package, comprising a means (11) for cutting up the package, means (21) for separating the package from its content and means (20) for removing the emptied package from the cutting means, said means (21) for separating the content at least from the package comprising means (13) for ripping the package open, one or more transporting means and a rotating drum (21) provided with openings through which the content separated from the package is allowed to leave the drum (18). Further, the sack cutting screw (11) is separated from the drum (18) and that below both the sack cutting screw (11) and the drum (17), a means (20) for collecting and transporting away the content of the sacks is arranged, said means being configured in such way that the content of the package is removed at one end, while the waste package is removed at the other end of said sack cutting means (10).

During drilling of offshore wells a drill liquid is required. Such drill liquid may be water based or oil based. The drill liquid consists of a mixture of a number of different chemicals and compounds, and several of these ingredients represent a risk for the human being. The chemicals are commonly supplied in sacks of 25-30 kg and the content of the sacks is fed into a mixer and mixed into a circulating drill fluid. The drill fluid has to be tailor made to the specific requirements at any time, the need for different mixtures often being changed. On this basis it is thus required that the mixing of the drill liquid is executed on the platform as an integral part of the drilling operation.
The problem to be solved is thus how to cut up the sacks and empty these in order to mix the content of the sacks into the circulating drill liquid in a most efficient manner. Such mixing should, amongst other due to the health hazards, but also from an economical point of view, be automatic and without representing a health risk for the operator.
A large number of different machines, performing such operations, are already available on the market.
U.S. Pat. No. 4,930,968 describes a sack cutting machine comprising a unit for cutting up the sack so that the powder inside may be released, a first transporting screw for transport of the powder and the sack; a drum for separating the powder from the sack, the first transport screw being concentrically arranged in the drum; a feeding screw arranged below the drum and in open communication with the drum for transport of the powder to a separate location and a means for collecting ripped, empty sacks, arranged at the opposite side of the drum and said first feeding screw, seen with respect to the feeding opening for filled sacks. According to this solution an intact sack with its powder content is fed into the machine at the end of the sack cutting means, whereupon the sack by means of the first transporting screw is moved in a direction towards a stopper whereby the sack is cut and the content released, whereupon the direction of rotation is reversed.
EP 1 123 868 describes a sack cutting machine in the form of a feeding screw, arranged in a tray, provided with fixed knives for cutting the sack, and a drum arranged at one end of the feeding screw, the content being separated from the sack in said drum. At the opposite end an opening directing towards a tray for collection of empty sacks is arranged.


A method of transmitting inband signaling messages in a mobile telecommunications network using SACCH burst. In order to avoid puncturing a fixed amount of bits out of every SACCH burst for inband signaling, the 40-bit FIRE code of the SACCH is replaced with a shorter CRC code, thereby creating unused bits for carrying the messages. After the SACCH block is shortened, a plurality of dummy bits are inserted into the shortened block prior to applying a ½ convolutional code to obtain the coded block. The coded block is further interleaved, reordered and mapped into 4 SACCH bursts. The dummy bits in each SACCH block are then replaced by the inband signaling for transmission.

During voice and data transmission, signaling messages are also conveyed over the air interface in addition to user data. Signaling messages allow the network and the mobile station to discuss the management of importance issues, such as resources and handovers. When traffic is ongoing, signaling messages are carried through the Associated Control Channels (ACCH). The Slow Associated Control Channel (SACCH) is used for non-urgent procedures—mainly for the transmission of radio measurement data needed for handover decisions on a dedicated physical subchannel. The SACCH has the particularity that continuous transmission must occur in both directions. The SACCH is actually always present on dedicated physical subchannels (3GPP TS 43.051 v5.1.0 Release 5). As specified in "Digital Cellular Telecommunications System (Phase 2+), Mobile Radio Interface Layer 3 Specification, Radio Resource Control Protocol" (GSM 04.18 v8.8.0 Release 1999), each SACCH block conveys: 1) one physical layer header of two octets (the physical layer implements a peer-to-peer protocol for the control of timing advance and power control at the operation on dedicated physical sub-channels, and 2) one Layer 2 frame of 21 octets. Thus, each SACCH block contains 184 information bits. When a 40-bit FIRE code and a 4-bit tail section are added to the information bits, the block code contains 228 bits. After the block code is encoded with a ½ convolutional code (of which the constraint length is 5) and interleaved, the coded SACCH block contains 456 bits reordered and partitioned into 4 blocks, each of which contains 114 bits of interleaved data. Each block is then mapped onto one burst of which the stealing flags are set to "1" (GSM TS 05.03 v8.6.1 Release 1999).
It has been proposed that a fixed amount of bits out of every SACCH burst is punctured in order to convey some signaling messages at a rate of once every 120 ms. However, such puncturing decreases the link level performance of the SACCH.
It is advantageous and desirable to provide a method of inband signaling using the SACCH without decreasing the link level performance of the SACCH.

Method of transmitting signaling messages in a mobile telecommunications network


A molded housing of suitable, non-conductive material encasing and segregating a plurality of spring-loaded terminal connector tabs that embody stab connections to receive wire in the rear of the housing for the purpose of conducting current through the insulated terminal tabs to an identical yet inverted hermaphroditic mate for the purpose of connecting multiple wires to multiple wire to wire connections, wire to fixture connections, or series harness connections and the like.

1. Field of the Invention
The present invention relates to a molded housing of suitable, non-conductive material encasing and segregating a plurality of spring-loaded terminal connector tabs that embody stab connections to receive wire in the rear of the housing for the purpose of conducting current through the insulated terminal tabs to an identical yet inverted hermaphroditic mate for the purpose of connecting wire to wire, fixtures, series harnesses and the like.
2. Description of the Prior Art
Hermaphroditic connectors provide reliable means for connecting and disconnecting a plurality of electrical conductors. The manufacturing advantages are obvious in that one piece serves as both pieces of a connective set. Previous patent examples attest to the practicality of manufacture, functionality of use and varied applications of hermaphroditic connectors. See Gettig, et al., U.S. Pat. No. 4,963,102, and Rudoy, et al., U.S. Pat. No. 5,800,196.
The preceding references depict hermaphroditic connectors with similar features to each other. Most of the connectors are configured to be factory wired with molded entry rears or at best require the use of a separate "crimp" type conductive terminal with a blade extension to be inserted into the harness at time of use. The most obvious difference distinguishing the present invention from the prior art is the embodiment of low pressure "stab" connectors located at the rear of the housing. This allows for the fast reliable and field operable attachment of wire to connector.

Hermaphroditic electrical coupling assembly


A test sheet is set in a droplet discharge device at a first distance. At least one droplet is discharged toward the test sheet from a nozzle formed in the droplet discharge device to form at least one first dot on the test sheet. The test sheet is set in the droplet discharge device at a second distance differing from the first distance. At least one droplet is discharged toward the test sheet from the nozzle to form at least one second dot on the test sheet. A nozzle position error or a nozzle discharge angle error are calculated from the position of the first dot, the position of the second dot, the first distance, and the second distance. Testing inkjet heads in this manner allows accurate testing for errors in nozzle position or discharge angle.

1. Field of the Invention
The invention relates to a method of testing a droplet discharge device.
2. Description of the Related Art
Inkjet heads and other droplet discharge devices are widely known. Droplet discharge devices discharge droplets from a nozzle and cause a liquid to accurately adhere to a target position. So that the liquid accurately adheres to the target position, the nozzle must be formed in a position as designed, and the droplet discharge device must be manufactured so that the droplet is discharged from the nozzle in the direction of the design. Therefore, the position of the nozzle of the droplet discharge device, the discharge angle of the droplets discharged from the nozzle, and other aspects are tested after the droplet discharge device is manufactured.
Testing methods such as that shown in FIG. 24 are used in conventional testing of droplet discharge devices. In this testing method, a transparent test sheet 300 is provided at a position of distance d from a droplet discharge device 301, and a CCD camera 302 is provided on the rear side of the test sheet 300. Droplets are discharged from a nozzle 303 formed in the droplet discharge device 301, and a liquid 304 adheres to the test sheet 300. Once the liquid 304 has adhered to the test sheet 300, the nozzle 303 and the adhered liquid 304 are photographed by the CCD camera 302. The photographed image is processed to detect the position of the nozzle 303 and the position where the liquid 304 adheres. Next, the horizontal deviation L of the position where the liquid 304 adhered and the position of the nozzle 303 is calculated. Once the deviation L is calculated, the discharge angle θ is calculated from distance d and deviation L. The data of the calculated nozzle position and discharge angle are fed back into the manufacturing process to enable the manufacture of droplet discharge devices of a high precision.

Method of testing a droplet discharge device


Provided are a preamble symbol generation method and receiving method, and a relevant frequency-domain symbol generation method and a relevant device, characterized in that the method comprises: generating a prefix according to a partial time-domain main body signal truncated from a time-domain main body signal; generating the hyper prefix according to the entirety or a portion of the partial time-domain main body signal; and generating time-domain symbol based on at least one of the cyclic prefix, the time-domain main body signal and the hyper prefix, the preamble symbol containing at least one of the time-domain symbols.

Typically, in order to enable a receiving end of an OFDM system to correctly demodulate data sent by a transmitting end, the OFDM system has to realize accurate and reliable time synchronization between the transmitting end and the receiving end. At the same time, since the OFDM system is very sensitive to the frequency offset of a carrier, the receiving end of the OFDM system also has to adopt an accurate and efficient carrier frequency estimation method, so as to precisely estimate and correct the carrier frequency offset.
At present, a signal of an OFDM system is composed of physical frames, and each physical frame generally has one synchronization frame head referred to as a preamble symbol or bootstrap, for realizing the time and frequency synchronization between a transmitting end and a receiving end. The preamble symbols is known to both the transmitting end and the receiving end, and is generally referred to as a P1 symbol. The usage of the P1 symbol or bootstrap symbol includes:                1) Enabling the receiving end to make a detection rapidly to determine whether a signal transmitted in a channel is a signal desired to be received;        2) providing a basic transmission parameter (e.g. the number of FFT points, frame type information, etc.), so that the receiving end can performing subsequent receiving processing;        3) detecting an initial carrier frequency offset and a timing error, and compensating to achieve frequency and timing synchronization; and        4) emergency alarm or broadcast system wakeup.
A P1 symbol design based on an existing time-domain structure is proposed in existing standards such as DVB_T2 standard, which well achieves the above-mentioned functions. However, there are still some limitations on low-complexity receiving algorithms. By way of example, in the case of long and multi-path channels with 1024, 542, or 482 samples, rough timing synchronization will cause great deviation, thus leading mistake when estimating integral frequency offset of the carrier in the frequency domain. Further, in a complex frequency selective fading channel, for example in a long multi-path channel, DBPSK differential decoding method may also fail. Moreover, since the time-domain structure of DVB_T2 does not include a cyclic prefix, when it is necessary to utilize the preamble symbol to conduct channel estimation, the frequency-domain channel estimation performance thereof will be severely degraded.

Preamble symbol receiving method and device


A method of operating a neural network for ecological and biological system modeling having a plurality of hidden layer neurons said method comprising: a plurality of network inputs and at least one network output, said plurality of neurons, each receiving a plurality of inputs applied to the network, reproduces the network using a regression model, and compares the output values with given target values, and using the comparison and goodness of fit to set the learning rules. The network does not require repetitive training and yields a global minimum for each given set of input variables.

Several approaches have been adopted in simulation of ecological and biological systems. Usually the initial approach to simulation of an ecosystem is to develop a simple linear model. That is to assume that if Y1=f(x1) and Y2=f(x2) then (Y1+Y2)=f(x1+x2) or, that no second interaction between the two variables controlling a process. Often this is not true, and linear model may only give an approximation (reasonable or otherwise) to the real system. Inherent in biological systems are non-linearities. Simulation models may be stochastic or deterministic. This simply denotes whether a model contains some random events or not. Deterministic models contain a sequence of events, which follow with complete certainty to produce a result not affected by chance events. Conversely, if one or more of the sequence pathways are selected on a probability basis, the model is stochastic or probabilistic. The mathematical approach to a computer model defines a number of system variables, which characterize and control the xe2x80x98flowxe2x80x99 between component segments of the model. The flow or interaction between component segments of the model is derived from transfer functions. The model driving equations (forcing functions) involve those external parameters required as input to the model but which are little affected by the model if at all.
Two basic strategies are used for modeling. Compartment models, which are usually simple linear systems of differential equations very often describing biomass changes or energy flow in a system. Their purpose is to analyze the performance of the model rather than necessarily to attempt to model the real system. The second and more detailed strategy that has been employed is the component approach of Holling (1969) (detailed in an article titled xe2x80x9cThe strategy of building models of complex ecological systemsxe2x80x9d in a book titled xe2x80x9cSystems analysis in ecologyxe2x80x9d by Watt K E F, (ed.) published by Academic Press N.Y. pages 195-214); or the building block by Kershaw and Harris (1969) (detailed in an article titled xe2x80x9cSimulation studies and ecology: A simple defined system modelxe2x80x9d in Statistical Ecology volume 3: pages 1-21, published by Penn. State Univ. Press). This follows a stepwise fashion, from an experimental examination of each block or component, in turn, to a series of equations relating the parameters involved in each component, and back to the experimental-testing of the model at each step.
High biocomplexity, high natural dynamics, and certain periodic processes such as habitat fragmentation characterize ecological and biological systems. While empirical/statistical models describe the global behavior of ecological and biological systems and models of differential equations try to represent single processes, there is another type of knowledge that handles processes and behavior patterns in a causal manner. This knowledge cannot be formalized in generic predicate logic or similar paradigms without losses. Therefore a new approach is required that will match the changing dynamics of ecosystems with high adaptability and built-in feed back. The processing engine of the foregoing may be implemented through artificial neural networks comprising a plurality of logic elements called neural circuits. A neuron is the fundamental building block of an artificial neural network. The computer model represents these neurons as well as the whole network by data structures. The data are structured in layers. Each layer or data set represents one or more neurons. The neurons are connected with each other and with the surroundings. The neuron has multiple inputs and a single output.
There are many types of neural network architectures. Such neural architectures as xe2x80x9cback propagationxe2x80x9d, xe2x80x9cperceptronxe2x80x9d and xe2x80x9cHopfield networkxe2x80x9d are the best known. Other neural network structures have been discussed extensively in a book titled xe2x80x9cSimulating Neural; Networksxe2x80x9d published in 1994 by Verlag Vieweg and authored by Norbert Hoffmann. The structure comprises of three or more layers, neurons connected to the input set and form a layer of input neurons, others transfer their output to the output set, and are called output neurons. The remaining neurons are not connected to the surroundings, and are called the hidden neurons. Each neuron in the hidden layer multiplies its inputs, as received from the input nodes, by a given weight to produce a product.
Most neural network structures have serious drawbacks. Which include time-consuming training of the networks for relatively complex problems such as that for ecological and biological systems simulation.
Another, disadvantage is that when weights converge, they usually converge to local minima, which gives erroneous solution. For example, a particular function may become slightly larger, regardless of how a particular parameter is moved. However, if the parameter were to be moved into a completely different place, the loss function may actually become smaller.
One can think of such local minima as local xe2x80x9cvalleyxe2x80x9d or minor xe2x80x9cdentsxe2x80x9d in the loss function. However, in most practical applications, local minima will produce xe2x80x9coutrageousxe2x80x9d and extremely large or small parameter estimates with very large standard errors. In such cases different start values have to be specified and tried again.
To avoid local minima, statistical methods such as Boltzman training or Cauchy training has been applied. However, the optimum solution is the xe2x80x9cbest fitxe2x80x9d global minimumxe2x80x9d for a given set of examples. The U.S. Pat. No. 5,781,701 to Wang 1998, establishes a method that uses a neural network which utilizes a plurality of neuron circuits which do not individually utilize any non-linear function or summing circuit and which each require only a multiplier circuit as its main processing element.
In summary, the present approach of simulating ecological and biological systems using conventional methods do not match the high biocomplexity, high natural dynamics, and periodicity that characterize such systems. Conventional neural network approach needs to be modified to fit the inherent natural biological and physiological processes between elements of the ecosystem model. In addition, the complex circuitry of conventional neural networks severely limits their implementation in the form of computer software, and hence its application in ecological system modeling.
What is therefore required is a straight-forward neural architecture that is easy to implement in form of a software which yields a global minimum to each given set of input vectors and does not require repetitive training.
A preferred embodiment of a neural network designed in accordance with the teachings of the present invention comprising input neurons and three layers of neurons by way of example. Input neurons serves an interconnect function, connecting external inputs to the network. A first layer of hidden neurons comprising neurons not connected to the surroundings. The second layer of hidden neurons receives inputs from the first. A third layer of neurons transfer their output values to the output set. They are called the output neurons.
In contrast to conventional artificial neural networks, a neural network constructed for ecological system scenarios in accordance with the present invention converges on a global solution using standard statistical regression model estimation, which can often be computed in a few minutes on a personal computer.
Moreover, in contrast to conventional approaches, there is provided in accordance to the teachings of the present invention a neural network which utilizes a plurality of neurons. The first layer of hidden neurons use non-linear estimation to predict the neuron weights from driving independent variables. The weights have established biological relationship with the neuron output.
Thus it will be appreciated that a neural network constructed in accordance with the present invention performs with accuracy, in less computational time and reduced cost and complexity of implementation, whether in a computer program or hardware design.
In addition, a neural network for ecological systems constructed in accordance with the present invention can have single or multiple outputs by providing multiple summing circuit for summing the outputs of the neurons.
Thus it is an advantage of the present invention to provide a neural network for ecosystems which utilizes a plurality of neurons, so that a neural network may be built comprising a very large number of such neurons processing inputs from a plurality of driving variables, resulting in a model which can simulate the high complexity and high temporal dynamics inherent in ecological and biological systems.
It is also an advantage of the present invention to provide a neural network for ecosystem modeling, which does not require repetitive training.
Yet another advantage of the present invention is to provide a neural network for ecosystem modeling which yields a global minimum to each given set of input variables.
It is also another advantage of the present invention to provide a method of modeling ecological and biological systems using a neural network in accordance with the present invention.
According to one aspect of the invention, there is provided a neural network for ecosystem modeling having a plurality of network inputs and at least one network output, the neural network comprising: a plurality of neurons, each neuron having a plurality of inputs and generating an output.
According to another aspect of the present invention, there is provided a method for training neural network comprising a plurality of neurons, which method requires estimation of loss function (to find the best fitting set of parameters) and to estimate the standard errors of parameter estimates via using algorithms (e.g quasi-Newton, Simplex, Hooke-Jeeves pattern moves, and Rosenbrock pattern search) to solve the values of each neuron weight and and hence output value.
According to yet another aspect of this invention there is provided a neural network for ecosystem modeling comprising: a plurality of network and at least one output; a plurality of neurons, each neuron receiving a plurality of inputs and generating an output; a method of operating the neural network, the method comprising the following steps: an initial iterative procedure comparing driving input variables (independent variables) to the weights (dependent variable), at each step, the program evaluates whether the fit of the model to data has improved from the previous step, i.e., how much xe2x80x9cerrorxe2x80x9d was lost between the previous and the current iteration, and calculating the loss function to determine how the goodness of the model fit to the data.
According to yet another aspect of the invention there is provided in a neural network for ecosystem modeling comprising: a plurality of network inputs and at least one network output; a plurality of neurons, each neuron receiving a plurality of inputs applied to the network, reproduces the network using a current model, and compares the output values with given target values and xe2x80x9chierarchially relatesxe2x80x9d (means that the current model is identical to the previous model with the exception of an addition or deletion of one or more driving or independent variables) to the previous model and using the comparison between the goodness of fit for the two models or difference to set the learning rules.

Neural network for modeling ecological and biological systems


This invention relates to a finger restraint device to be worn by sufferers of hand and wrist injuries such as carpal tunnel syndrome, tendinitis, arthritis, and wrist sprain. The device comprises a finger restraining system in the form of a finger, hand and wrist covering which will support the wearer's fingers in a curled position, or to provide a core around which the fingers would normally grasp and be restrained by the covering. This places flexor and extensor tendons in a state of isotonic tension, and promotes a natural position with alignment of the wrist and tendons, ligaments, nerves, and blood vessels in the hand and wrist.

1. Field of the Invention
This invention relates to the field of medical devices for treatment, and alleviation of symptoms of carpal tunnel syndrome, arthritis, tendinitis, and wrist sprain.
Common methods of treatment of these injuries and to alleviate symptoms are to restrict movement or immobilize the wrist using splits or external compression thus reducing trauma caused by bending the wrist. Prior art devices allow the fingers to move and flex. This means tendons, and ligaments can rub against nerves, bone structures, and blood vessels that may be further injured. This inappropriate movement may exacerbate the existing injury because the wrist is restrained from assuming a natural position.
Dr. Emil Pascarelli, "Repetitive Strain Injury", states that the use of rigid braces can interfere with the proper directional growth of scar tissue.
Dr. David Rumpel (Contra Costa Times Feb. 1, 1994) reported that devices used to restrain wrist movement while at the same time allow the fingers to flex and move did not reduce carpal tunnel pressure, and could actually increase the risk of carpal tunnel injury in some people.
The same thing can be said for tendinitis, and wrist sprains. Braces prevent the wrist from bending, but make no allowance for natural movement and normal position of the wrist's internal parts.
Surgery, an invasive action, has been used to relieve carpal tunnel symptoms however it is often only temporary relief from carpal tunnel injuries.
Without some form of wrist restraint these injures can be further exacerbated by the tendency of individuals to sleep with their hands in a fetal drop position. These situations further inflame the damaged tissue in the hand, and wrist.
This invention pertains to a finger restraining device designed to produce natural wrist position and alignment of tendons, nerves, and blood vessels passing thru the carpal tunnel area of the hand. It improves on prior art because it is more comfortable to wear, and improves on the immobilization of the internal structures of the hand and wrist.
The wrist and hand area contain many parts that are subject to injury. These include bone structures, nerves, blood vessels, tendons, and ligaments. Injuries to the hand and wrist include arthritis, repetitive stress injury (carpal tunnel syndrome), tendinitis, and sprains.
People suffering from these afflictions experience stiffness, tingling, numbness, loss of strength, and paraesthesia in their hands and fingers. This often disturbs their sleep causing them to awake in pain.
Arthritis is different from the others listed and its symptoms are frequently treated using warmth, moisture, and compression to provide temporary relief from pain and stiffness. Prior art devices include heating pads, and thermal gloves designed to compress the fingers, palm, and wrist. These devices do not address one of the real causes of stiff fingers. As people age their tendons tend to shrink during periods of non-use such as sleeping or resting. This shrinking is what creates some of the stiffness arthritis sufferers feel. Other disadvantages of these devices are that it is difficult to keep one's hand on a heating pad while sleeping, and gloves require a person to give up the tactile sense of feeling in their finger tips.
Carpal tunnel syndrome, tendinitis, and wrist sprain are another category of injury.
2. Background Art
The following patents on this subject were reviewed, and found to be different from the proposed invention.
U.S. Pat. No. 5,466,215 (Lair) makes reference to restrictive splints, which prevent natural wrist and finger movements. It also stresses two motions that should be minimized during sleep in order to treat, or reduce symptoms of carpal tunnel injuries. These are fetal hand drop, and backflip of the hand. Lair further states that rigid devices that encompass the wrist can also produce additional pressure on nerves just below the skin surface that are proximal to the bone structure, and blood vessels. These devices are also uncomfortable to wear. Lair also cites the high incidence of non-compliance of wearing prior art restrictive devices because they are uncomfortable, and difficult to apply with one hand.
Wrist supports do have a high incidence of non-compliance of instructed use especially during sleep, and U.S. Pat. No. 5,417,645 (Lemmen) notes that existing devices are lumpy, stiff, or bulky, and that there is a need for a device that is comfortable to use.
U.S. Pat. No. 5,385,537 (Davini) states the "best way to recovery (for wrist injuries) is non-use." At present there are no existing devices that immobilize the internal structures of the wrist in a natural position and that also provide for immediate use of the wearer's fingers when necessary.
Stretching of connective tissue is also an important consideration when treating joint injuries. U.S. Pat. No. 5,468,220 (Sucher) declares that the most effective recovery devices for joint injuries are those that provide a long period of low force stretching of connective tissue, and which also produce the greatest amount of permanent elongation of connective tissue. Low force stretching is frequently accomplished thru exercises that open and close the hand. One such exercise device, U.S. Pat. No. 5,492,525 (Gibney), provides for active stretching exercise during waking hours however no devices exist until now that promote stretching during periods of sleep.
Bruckner et al. (U.S. Pat. No. 4,290,147), Portal (U.S. Pat. No. 2,284,300) and Gatley et al. (U.S. Pat. No. 1,554,807) disclose the state of art of various orthopedic hand wraps. Bruckner discloses the tubular hand wraps have two open ends and an internal core located on the interior of the hand wrap configured for gripping. However, Bruckner does not disclose or teach the internal core having a sling or that the internal core is removable. Portal discloses in FIGS. 6-9 a glove with one open end that includes a.sub.-- sling and an internal core attached to the interior of the tubular hand wrap. However, Portal does not disclose or teach having two open ends or that the internal core is removable. Gately discloses that it is known in the art to include a thumb slit in these type of gloves.
Helferich (U.S. Pat. No. D 259,955), McLaurin-Smith (U.S. Pat. No. 4,961,418) and Tucker (U.S. Pat. No. 1,227,700) disclose the state of the art of fabric, tubular hand wraps. McLaurin-Smith discloses a heat-retaining fabric. None of these references disclose or teach placing a sling with an internal core in the interior of the tubular wrap being configured to be gripped by the user.
Schiavitto (U.S. Pat. No. 3,703,171) discloses that it is known in the orthopedic art to have a tubular member that has one end with a smaller diameter than the other in order to fit over the varying diameter of limbs.
Shields (U.S. Pat. No. 5,217,029) and Owen (U.S. Pat. No. 3,774,242) disclose therapeutic gloves that include an open end and gripping a core on the interior of the wrap. However, these reference do not disclose or suggests including a sling with a core attached to the interior of the wrap.
Meldeau (U.S. Pat. No. 5,353,440), Mann (U.S. Pat. No. 4,977,890, and Shelly (U.S. Pat. No. 5,37,620) disclose hand braces that have an internal core with a sling that is configured to be gripped by the user it for treating various ailments. Meldeau discloses that the internal core is removable from the sling. However none of these references disclose or teach the sling being attached to the interior of a tubular wrap.
U.S. Pat. No. 4,531,241, Berger A glove designed to minimize transmission of vibrations from hand held devices to the palm and wrist. Not applicable to my invention.
U.S. Pat. No. 4,829,604, Allen et al. This device is an adjustable wristlet that provides external support to the wrist by tightening of an adjustable strap. Not applicable to my invention.
U.S. Pat. No. 4,850,341, Fabry et al. This is an open ended finger less glove having a pad to cushion and protect the median nerve area of the hand. Not applicable to my invention.
U.S. Pat. No. 4,883,073, Aziz This device uses a flexible substrate, and splints to limit the range of forward (fetal hand drop), and backward (backflip) movement of the wrist. Not applicable to my invention.
U.S. Pat. No. 4 899 763, Sebastian et al. This device uses external restraints to limit wrist motion. In this case it is inflated air chambers that provide the rigidity. Not applicable to my invention.
U.S. Pat. No. 4,941,460, Working This device fastens to the hand, and forearm and spans the wrist with a rigid piece to immobilize the wrist. Not applicable to my invention.
U.S. Pat. No. 5,003,967, McConnell This device forces the wearer's hand into a fist using a wrapping method. The wearer must unwrap their hand in order to use their fingers. Not applicable to my invention.
U.S. Pat. No. 5,014,689, Meunchen et al. This device uses external means to limit hand extension, and flexion, ulnar, and radial deviation. This device is a flexible cavity that envelopes the outstretched hand of the wearer. It has a means for uncovering the hand without removing it from the wearer. No means are used to immobilize the fingers in the form of a fist.
It does not have any means to force the fingers to curl, nor does it have an insert for gripping. The wearer must pull on a flap in order to uncover the hand, whereas my invention has an open end and allows the wearer immediate uncovering of their fingers. Not applicable to my invention.
U.S. Pat. No. 5,058,573, Hess et al. This is an elastic sleeve with a thumb hole to be used as a bandage for the hand. It has no provisions for curling the fingers into a fist. Not applicable to my invention.
U.S. Pat. No. 5,152,740, Harkensee et al. This device is an inflatable bladder that fits into the palm of the wearer. At the recommended 20 PSI pressure, the bladder becomes a rigid tube pressing against the straps on the dorsal side of the hand. does not restrain the fingers in a curled position, and is attached to the hand using straps and hook and loop fasteners. It is designed to support the bones in the palmar region. The wearer must deflate the bladder to remove the device to utilize their hands. Not applicable to my invention.
U.S. Pat. No. 5,160,314, Peters This device is a sleeve with a thumb loop, and removable stay. It keeps the wearer's wrist immobile in a fixed position. Not applicable to my invention.
U.S. Pat. No. 5,203,766, Carter et al. This device is a splint made of rigid or semi rigid materials, pins with pivot points, and metal. It is designed to immobilize the wrist in a set position. It fastens to the forearm, and hand to span the wrist joint. Not applicable to my invention.
U.S. Pat. No. 5,205,812, Wasserman This device is a rigid splint, It has a hand engagement feature that is designed to prevent the fingers from curling. It also immobilizes the wrist. Not applicable to my invention.
U.S. Pat. No. 5,254,078, Carter et al. This is a rigid device requiring adjustable opposing plates which restrict wrist movement while the fingers can be moved. Not applicable to my invention.
U.S. Pat. No. 5,256,136, Sucher This device uses contoured, and rigid supports to hold the extended fingers back, and position the wrist, and thumb in order to stretch the transverse carpal ligament and enlarge the carpal canal, and relieve pressure on the median nerve.
My new invention positions the fingers forward in a normal fist position. Not applicable to my invention.
U.S. Pat. No. 5,358,471, Klotz This has rigid side pieces that are uncomfortable to the wearer who may lay on their hand. It has a hand grip for preventing the fingers to close into a fist. My invention forces the fingers to close normally, and has no rigid sides. Not applicable to my invention.
U.S. Pat. No. 5,370,606, Martel et al. This device has finger holes for all digits.
It is a fingerless glove with no provision for curling the wearer's fingers into a fist. Not applicable to my invention.
U.S. Pat. No. 5,376,066, Phillips et al. This device positions the wrist in a fixed flexion position. This device has one finger opening for each digit. It holds the wrist in an abnormal position when the wearer is moving the fingers, and gripping objects. Not applicable to my invention.
U.S. Pat. No. 5,385,537, Davini This device is a wrist strap. Davini does cite that the "best way to recovery (of wrist injuries) is non-use," however his device is not applicable to my invention.
U.S. Pat. No. 5,397,296, Sydor et al. This contains wraps, and stays for positioning the wrist as if it were a splint, and is not applicable to my invention.
U.S. Pat. No. 5,409,451, Daneman This invention serves as a splint immobilizing the wrist while the fingers are allowed to move. Not applicable to my invention.
U.S. Pat. No. 5,413,553, Downes This invention demonstrates that it is possible to have devices that do not require supporting of the wrist. It differs in that it has holes for all fingers, It uses non-elastic material on the dorsal side of the hand, and holds the wrist in flexion position. Downes cites the importance of, and the need for non-invasive means for rehabilitative, and preventative devices. Not applicable to my invention.
U.S. Pat. No. 5,417,645, Lemmen declares the need for a device that is comfortable to use, and that existing devices surveyed are lumpy, stiff, or bulky. This device serves as a reminder of the correct wrist position but the wearer must be conscious to be reminded. This device forces the wrist into a cocked up position which can be abnormal for some finger activities. It also fastens over the wrist and forearm spanning the joint. Not applicable to my invention.
U.S. Pat. No. 5,421,811, More et al. The device is similar to other compression wraps except that it helps position the wearers wrist at an angle. It uses external means to limit the range of motion of the wrist while allowing the fingers to move. Not applicable to my invention.
U.S. Pat. No. 5,441,058, Fareed This device claims to create proper alignment in the carpal tunnel by compressing the forearm muscles. Not applicable to my invention.
U.S. Pat. No. 5,444,874, Samelian A hand covering designed for normal extended finger positions. Not applicable to my invention.
U.S. Pat. No. 5,447,490, Fula et al. A device designed to curl fingers but has no means for the wearer to use their restricted fingers without removing part of the device. Not applicable to my invention.
U.S. Pat. No. 5,454,380, Gates This device is a rigid container into which the wearer inserts their hand. Various devices such as a knife can be affixed to the container so the wearer does not need to bend their fingers to grip. Not applicable to my invention.
U.S. Pat. No. 5,466,215, Lair et al. This device uses a loop fastened to a wristlet to restrict downward movement of the wrist. The loop encompasses one or more fingers, and when properly worn limits downward motion of the hand. Not applicable to my invention.
U.S. Pat. No. 5,468,220, Sucher Sucher states the most effective recovery devices are those with the longest period of low force stretching that produces the greatest amount of permanent elongation of connective tissue.
This is a bracelet that applies pressure to the carpal tunnel area. It uses pressure to stretch the transverse carpal ligament and related or associated structures of the wrist. Not applicable to my invention.
U.S. Pat. No. 5,476,439, Robinson This device is a full fingered glove with means to externally restrain movement of individual fingers. Not applicable to my invention.
U.S. Pat. No. 5,478,306, Stoner This device is a wristlet positioned over the median nerve area of the wrist. Not applicable to my invention.
In light of the above art, it would not have been obvious to one skilled in the art at the time of the invention to make a tubular hand wrap with ends of varying diameter and to attach a sling with a removable core to the interior of the wrap.
A non-surgical and more natural solution to these situations is to use a device that does not place pressure on the wrist, provides for stretching the tendons passing thru the wrist, promotes natural position of the wrist, alignment of the tendons, ligaments, nerves, and blood vessels passing through the wrist. It should also reduce fetal hand drop, and wrist backflip. The device should be passive and produce results when a person is sleeping. It should be comfortable to wear and should allow the user immediate freedom to use their fingers. My invention accomplishes these criteria.


A cable for distributed fiber optic sensing comprising a flexible tape, an optical fiber suitable for Brillouin scattering measurement forming at least two lengths, and at least one free end of at least one length being connectable to a reading unit, wherein at least a section of the longitudinal length of the flexible tape is situated between at least a section of the two lengths such that the two lengths are in close proximity such that a temperature gradient between the two lengths is minimized, and wherein the section of the tape and the section of lengths can flex together.

Deformation sensing can be achieved by placing point sensors across a certain range. However, this raises a problem when large engineering projects require the sensing to be done over several kilometers because numerous point sensors are required.
Conventionally, a distributed sensor is a device with a linear measurement basis, which is sensitive to a measure and at any of its points. Distributed optical fibre sensing is not well known and has been slow to be accepted into conservative large engineering projects where long sensors would be advantageous. The optical fibre is sensitive over its entire length. A single distributed optical fibre sensor can replace thousands of discrete point sensors. Traditionally, optical fibre connections were thought to be costly and troublesome. However, the cost of using fibre optics has fallen rapidly. Use of optical fibres is advantageous because they are tough, durable, stable, and can be applied in harsh environments. The fibres are also immune to electrical interference common in industrial environments and have small cross-sections, making them suitable for embedment in composite materials.
There are different types of optical fibre distributed sensors—those that measure temperature distributions by detecting Raman scattered light in a fibre, others that measure strain distributions by detecting Rayleigh scattered light, and still others that measure both temperature and strain distributions by detecting Brillouin scattered light. The sensors that are based on measurement of Brillouin scattered light include BOTDA (Brillouin Optical Time Domain Analysis), BOTDR (Brillouin Optical Time Domain Reflectometry), BOFDA (Brillouin Optical Frequency Domain Analysis) and correlation-based Brillouin distributed sensors.
A BOTDA sensor applies Brillouin Scattering, a method of detecting distributed temperature and strain using a non-linear optical effect. Generally, fibre strain and temperature are linearly associated with the frequency shift and hence the wavelength of light, caused by scattered light. Both strain and temperature cause a shift in the Brillouin frequency. The BOTDA sensor measures changes in the local strain and/or temperature conditions of an optical fibre through analysis of the Brillouin frequency of the fibre at any point. Position is determined by the round-trip transit time of the optical signal in the fibre, which is approximately 0.1 m/ns in typical fibres.
Typical fibres exhibit coefficients of change in Brillouin frequency Cε0.05 MHz per ppm change in length (microstrain, με) and CT≈1 MHz per ° C. change in temperature. The Brillouin frequency (vB) at a point z is therefore given by:vB(z)=vB0(z)+Cε·ε(z)+CT·T(z)  Eq.1where vB0(z) is the reference Brillouin frequency and T(z) and ε(z) are the local temperature and strain conditions respectively.
Typical BOTDA sensors can resolve around 1 MHz changes in Brillouin frequency resulting in a strain resolution of about 20 με or a temperature resolution of about 1° C. Since both temperature and strain affect the Brillouin frequency in the same way, it is normally impossible to identify which parameter has changed without further information or assumption (for instance, an assumption that the sensor is isothermal, or knowledge that the fibre is strain-free).
Some prior art sensors use a single strand of optical fibre. This is problematic since the Brillouin frequency is dependent on both local strain and temperature variables. Therefore, two strands of sensing fibre are often used in proximity of each other and placed in parallel—one detects strain and temperature, and the other detects temperature only. The fibre that detects temperature only is situated in a mechanically isolated tube to replicate a strain-free environment. Calculations of Brillouin frequency using such a set-up are inaccurate, however, since they are made with the assumption that the temperature is the same for both fibres; however, in reality, it is common for the temperatures to differ. In addition, even when the temperatures of the fibres are the same, thermal expansion of the host material will cause additional temperature-dependant strain that is not compensated for by the temperature-only fibre.
Other prior art sensors comprise at least two optical fibres in a single substrate with one of them measuring strain and temperature, and another measuring temperature only. Although this increases the likelihood that the fibres experience the same temperature conditions, thermal expansion can cause additional strain in the strain-measuring fibre that is not compensated for by the temperature-measuring fibre. In addition, these devices place the strain-sensing fibre along the neutral axis of the substrate and therefore cannot measure the curvature or displacement of the substrate itself.

Flexible fibre optic deformation sensor system and method


A low loss microwave surface acoustic wave filter, comprising input (2, 3) and output (4, 5) transducers, acoustically associated with coupling transducers (6, 7).. The relative positions of the transducers 2 to 7) and of their O reflectors are chosen, having regard to the weightings of the coupling transducers (6, 7) in order to obtain the desired transfer function for this filter.

1. Field of the Invention
The present invention relates to a low loss microwave surface acoustic wave filter.
2. Discussion of the Background
The type of high performance, low loss filter to which the invention relates is, for example, as described in the article by Messrs. DUFILIE, HODE and DESBOIS: "A low loss high performance filter structure", IEEE 1988 Ultrasonic Symposium (Chicago), pages 1 to 4. The filter described in this article comprises:
two unidirectional input transducers placed symmetrically on either side of a first bidirectional coupling transducer and acoustically connected to the latter;
a second bidirectional coupling transducer electrically connected to this first bidirectional coupling transducer;
two unidirectional output transducers, placed symmetrically on either side of this second bidirectional coupling transducer and acoustically connected to the latter; and
two input and output terminals the first electrically connected to the two input transducers and the other to the two output transducers respectively.


A method and circuit are disclosed for providing sector protection to sectors of nonvolatile memory cells in a nonvolatile memory device. The circuit includes maintaining sector protection information in the core of memory cells in the nonvolatile memory device. In this way, the circuitry and/or algorithms utilized for reading and modifying memory cells in the memory cell core that maintain the sector protection information is the same utilized for reading and modifying the other memory cells in the core.

1. Technical Field of the Invention
The present invention relates to nonvolatile memory devices, and particularly to nonvolatile memory devices having sector protection circuitry.
2. Description of the Related Art
The first nonvolatile memories were electrically programmable read-only memories (EPROMS) . In these memories, the memory cells include a floating-gate transistor that is programmable using the hot carrier effect. Programming of an EPROM memory cell includes applying a potential difference between the drain and the source of the floating gate transistor in the presence of a high potential difference (of about 20 volts, this value varying according to the desired programming speed) between the control gate and the source. The application of the first of these potential differences generates an electrical field that gives rise to a flow of electrons in the channel. These electrons collide with atoms of the channel, causing the appearance of new free electrons. These electrons have very high energy (hence the term xe2x80x9chot carriersxe2x80x9d). The high difference in potential between the control gate and the source of the floating gate transistor gives rise to a strong electrical field between the floating gate and the substrate, the effect of which is that certain of these electrons are injected into the floating gate, thus putting the memory cell in a state known as a xe2x80x9cprogrammedxe2x80x9d state.
The fact that the programming of a memory cell requires the application of voltages both to the control gate and to the drain of the floating-gate transistor eliminates the need for the use of a selection transistor to program one particular memory cell without programming the others. This results in a relatively small silicon area and the effectuation of large scale integration . By contrast, the erasure of all the memory cells of the memory is done substantially simultaneously by exposing the memory cells to ultraviolet radiation.
In addressing the need to individually erase EPROM memory cells, electrically erasable programmable read only memories (EEPROMs) were created. These memories are electrically programmable and erasable by tunnel effect (i.e., the Fowler Nordheim effect) . The memory cells have a floating-gate transistor whose drain is connected to the bit line by a selection transistor. The gate of the selection transistor is connected to the word line. The gate of the floating-gate transistor is controlled by a bias transistor. Generally, the source of the floating gate transistor is connected to a reference potential, such as ground. These floating-gate transistors have an oxide layer between the substrate and the floating gate that is very thin to enable the transfer of charges by tunnel effect. The advantage of EEPROMs as compared with EPROMs lies in the fact that each memory cell is programmable and erasable independently of the other EEPROM cells. The tradeoff here is that a larger surface area of silicon is required and therefore a smaller scale of integration is achieved.
A third type of memory has more recently gained popularity. This type of memory, flash EPROMs, combines the relatively high integration of EPROMs with the ease of programming and erasure of EEPROMs. Flash memory cells can be individually programmed utilizing the hot carrier effect in the same way as EPROM cells are programmed. Flash memory cells are also electrically erasable by the tunnel effect. The memory cells of a flash EPROM memory includes a floating-gate transistor that has an oxide layer whose thickness is greater than the oxide layer thickness of an EEPROM floating gate transistor but smaller than the oxide layer thickness of an EPROM floating gate transistor. Consequently, the flash memory cell is capable of erasure by the tunnel effect. For erasure, a highly negative potential difference is created between the control gate and the source of the floating gate transistor, the drain being left in the high impedance state or connected to the ground potential so that a high electrical field is created which tends to remove the electrons from the floating gate.
Referring to FIG. 1, flash EPROM devices, hereinafter referred to as flash memory devices, typically include at least one array A of flash memory cells organized into rows and columns of flash memory cells. Array A is typically partitioned into blocks B, each of which is further divided into sectors S. A row decoder R and column decoder C are used to select a single row and at least one column of memory cells based upon the value of an externally generated address applied to the flash memory device. Sense amplifiers SA are coupled to the column lines corresponding to the columns of memory cells to amplify the voltage levels on the addressed column lines corresponding to the data values stored in the addressed flash memory cells. The particular implementations of array A, the row and column decoders and sense amplifiers SA are known in the art and will not be described further for reasons of simplicity.
Conventional nonvolatile memory devices, including flash memory devices, typically provide some type of modify protection so that one or more sectors in the nonvolatile memory device is read only. In one prior implementation, sector protection for a flash memory device is effectuated using software external to the nonvolatile memory device and volatile circuitry. In another prior implementation, sector protection is performed within the flash memory device in nonvolatile circuitry. In this implementation, the flash memory device includes sector protection circuitry for preventing data modification within an identified sector.
With reference to FIG. 1, the sector protection circuitry includes nonvolatile secondary storage elements disposed adjacent array A in the periphery of the flash memory device, for storing information that identifies sectors S that are to be modify protected. A command user interface U receives user-generated memory access operation commands and sends command information to circuits within the flash memory device for executing and/or managing the execution of the user-generated commands.
The existing flash memory device further includes access circuitry for reading, programming and erasing the secondary storage elements. A controller generally manages memory read and memory modify operations of memory cells within array A. Prior to managing/controlling a user-requested memory modify operation, the controller receives sector protection information from the secondary storage elements as well as user command information from the command user interface U, and determines whether the flash memory cells to be modified by the user-requested memory modify operation is in a sector S that is modify protected. Upon an affirmative determination that the flash memory cells to be modified are in a modify protected sector S, the controller prevents the memory modify operation from performing. Otherwise, the controller controls the various components/blocks within the flash memory device for executing the user-requested memory modify operation.
One shortcoming in having the above-discussed sector protection circuitry within the flash memory device is that rather complex algorithms are necessary in order to modify the information maintained by the secondary storage elements. The complex algorithms understandably result in more complicated circuitry being used in the existing flash memory device.
Based upon the foregoing, there is a need for more easily providing sector protection within a nonvolatile memory device, such as a flash memory.
Embodiments of the present invention overcome shortcomings in prior flash memory devices and satisfy a significant need for a nonvolatile memory device having a simpler technique for providing sector protection. In embodiments of the present invention, sector protection information is maintained in a set of memory cells in the core of nonvolatile memory cells. Control circuitry in the nonvolatile memory device selectively prevents memory modify operations in an addressed sector from being performed upon an affirmative determination that a memory cell in the set indicates that the addressed sector is modify protected. By including sector protection information in the core of memory cells, the circuitry used for reading and modifying the set of memory cells containing the sector protection information is the same circuitry used for reading and modifying the other memory cells in the memory cell core.

Sector protection circuit and method for flash memory devices


The present invention relates to a camera module configured to prevent de-focusing during correction of hand-shake, and to prevent damages to devices during correction of hand-shake, the module including: a module part including a lens assembly formed with at least one or more lenses, an image sensor having an image pickup device for converting light concentrated through the lens to an electrical signal, and a PCB (Printed Circuit Board) mounted with the image sensor; a case supporting the module part by accommodating the module part; a driving part tilting the module part; and a rotation preventing part preventing the module part from rotating on a vertical axis.

Recently, demands on a small-sized compact camera module are on the increase for use in various multimedia fields including notebook type personal computers, camera phones, PDAs (Personal Digital Assistants), smart phones and toys, and in image input equipment including monitoring cameras and information terminals for video tape recorders.
Generally, the compact camera module is applied to portable communication devices including camera phones, PDAs (Personal Digital Assistants) and smart phones and to various IT (Information Technology) devices.
The camera module is generally manufactured using an image sensor or a photo-electric conversion device of a CCD (Charge Coupled Apparatus) type or a CMOS (Complementary Metal Oxide Semiconductor) type to converge light from an object to a photosensitive element, to form an image of the object and display the image on a display device.
Furthermore, the camera module is manufactured to enable a focus adjustment for adjusting a size of an image, where a driving source is installed and a plurality of lenses is moved to change a relative distance for adjustment of an optical focal length.
At this time, when a user attempts to capture an image, a focus of the camera module is blurred by vibration of the user's hands, and therefore a reduction in the quality of a captured image may occur. That is, when there is vibration in a user's hands which hold the camera module, the subject image moves to a different location and therefore the focus of the camera vibrates, so that the phenomenon of blurring of the subject image may occur.
A hand-shake correction mechanism is a device applied to preventing a reduction in the quality of a captured image caused by hand-shake during photographing. A conventional hand-shake correction mechanism was mainly used for a digital camera. This is because a large-sized camera module is easier in application of the hand-shake correction mechanism than a compact-sized camera module used for mobile phones.
However, concomitant with demands requiring a high quality image in a compact-sized camera module as that of a digital camera, a hand-shake correction mechanism has been applied to mobile compact-sized camera module, and as a result, attempts at developing and researching the hand-shake correction mechanism have been actively made.
The conventional hand-shake correction mechanism can be generally classified into four categories: that is, a hand-shake correction optical lens moving method, an image sensor moving method, a prism refraction method, and camera module tilting method.
FIGS. 1 and 2 are perspective views illustrating a hand-shake correction camera module by the typical tilting method.
Referring to FIGS. 1 and 2, a module part (10), which is an image sensor converting an optical signal to an electrical signal, includes a lens assembly formed with a plurality of lenses for concentrating light, a cover encasing the lens assembly and a PCB (Printed Circuit Board) processing a signal from the image sensor.
The module part (10) is inserted into a case (20) to tilt in response to movement of a moving part, where the module part (10) tilts to 'a' direction and 'b' direction in response to movement of the module part (10) caused by hand-shake. At this time, referring to FIG. 2, the module part (10) may tilt to only one direction of 'a' direction or 'b' direction, but largely tilts to both directions because the hand-shake mostly occurs three dimensionally.
However, a rotational movement to 'c' direction (rotation of module part, 10) may occur during tilting movement, and in this case, a focus is disadvantageously warped to correct the hand-shake. On top of that, there may occur problems such as damages to the module part (10) and the case (20) caused by contact with the case (20) during rotating movement of the module part (10) and damages to the moving part (10) caused by excessive rotating movement of the module part (10).

Camera module having rotation prevention means


In a music apparatus, an operator panel designates a first style of automatic play. A tone generator sequentially generates musical tones to produce the automatic play in the designated first style. A DSP applies a first effect to the musical tones in matching with the first style of the automatic play. A CPU operates when the operator panel commands a style change from the first style to a second style during the course of the automatic play for controlling the tone generator to switch the automatic play to the second style. The CPU further operates when the style change necessitates an effect change from the first effect to a second effect matching the second style in a transient period for controlling the DSP before the controlling of the tone generator to complete the effect change within the transient period so that the DSP can apply the second effect to the musical tones timely when the automatic play is switched from the first style to the second style.

1. Field of the Invention
The present invention generally relates to an electronic musical instrument having an automatic accompaniment capability and an effect application capability.
2. Description of Related Art
An electronic musical instrument is configured to execute an automatic accompaniment. The electronic musical instrument can change a style of the currently executed automatic accompaniment to another style. In one change mode, when control information for instructing change of the automatic accompaniment style is reproduced from a storage device during automatic play, the change is executed according to this control information. In another change mode, when the user instructs a style change by predetermined switch operation, a specified new is effected at an end bar of the current measure immediately after the instruction. Sometimes, it is required, in an electronic musical instrument of the above-mentioned type, to change an acoustic effect applied to music tones of the automatic accompaniment to another acoustic effect when a style change operation is conducted. In such a situation, an effect change operation is executed in coincidence with the style change operation.
However, the above-mentioned conventional electronic musical instrument may involve a drawback such as noise generation due to effect change operation when the same is executed during automatic accompaniment. To avoid this drawback, the effect change operation is executed according to steps shown in FIG. 5. To be specific, an effect currently applied is faded out, and then a work memory (RAM) used for effect application is cleared. Next, fade-in is executed to gradually start application of a new effect. These steps inevitably take about 200 ms for the effect change operation to be completed. Consequently, in the above-mentioned conventional electronic musical instrument, when the style change is actually made from an old style to a new style together with the effect change to be made accompanying the style change, it takes time for a new effect to be applied to music tones. This may cause a problem that the new effect is not applied to the first music tone after the style change. For example, when executing effect change operation such that a chorus effect is selected as the style change is made, the chorus effect may not be applied to the first music tone following that style change. This lack of the chorus effect from the first music tone gives the listener the impression that something is out of place. This impression is especially emphasized when an acoustic effect to a percussion instrument tone has been changed.

Automatic accompaniment apparatus with concurrent change of music style and acoustic effect


A system for displaying data includes a display unit and a transmitting unit. A display unit has a housing that defines an ambient light window and a viewing window. A data display is positioned inside the housing, and optics are included for guiding light from the ambient light window through the display and out the viewing window.

Prior art displays are often overwhelmed ("washed out") in high ambient light conditions and thus are not visible to a user. A common example of this is a laptop computer LCD display which utilizes a backlight to illuminate a LCD panel. This works effectively when the LCD backlight is brighter than the ambient light that shines on the LCD. However, due to packaging and battery life constraints, the typical laptop LCD backlight is not bright enough to overcome high levels of ambient light, such as direct sunlight, and the display becomes unreadable in these conditions. Further, prior art displays often require high capacity power sources to operate, and prior art mobile displays are often inconvenient to use, especially while performing a concurrent task.
Portable electronic devices such as electronic multimeters, mobile phones, portable music players, handheld GPS units, and others bring many conveniences to their users. However, a major disadvantage of such devices is that their displays (which provide data critical to their operation) typically reside solely on the device. This means that when the user wishes to read information off of the device, the user is required to physically move the device into the user's field of view. This requirement can be very inconvenient when the user is wearing the device (e.g., on a belt clip) or when the user has the device in a pocket. This requirement can also be very inconvenient and even dangerous when the user has his hands otherwise occupied and/or is simultaneously performing a task that is visually intensive (e.g., driving, cycling, inspecting, and performing construction or repair work). Enabling visual information from these pre-existing devices to be seen in a user's line of sight would increase both safety and convenience.
Head mounted displays have been devised to lessen the inconvenience related with some mobile displays; but head mounted displays are only available for a small range of devices and uses. Generally, prior art head mounted displays are one of two types: unwired battery powered head mounted displays (for maintenance work or entertainment, for example) and wired head mounted displays that do not rely on their own power sources (military-type displays that deliver information to pilots, for example). Both have important limitations associated with use in high ambient light conditions, including the "washing out" problem noted above.
In addition, prior art unwired battery powered head mounted displays require a significant amount of power to illuminate the displays, and thus must include powerful batteries. This requirement for power can significantly add to the display's cost, size, and weight, as larger and/or more expensive batteries are required or more powerful artificial light sources are used. Alternately, this power requirement can reduce the total operating time available to the user, which reduces the usefulness of the displays.
Prior art wired head mounted displays generally operate from larger power sources accessed through the wires and do not suffer the need for strict power conservation. However, they can still benefit from the use of smaller, less powerful artificial light sources or from the outright elimination of artificial light sources in order to reduce weight, size, cost, and/or power consumption.

Ambient light display and system for displaying data


A cam phaser is disclosed for adjusting the angular position of a camshaft relative to a crankshaft. In a first embodiment, a rotatable camshaft has an interior passageway and at least one cam operative to effect actuation of an engine valve. A first drive member is connectable to the crankshaft for rotational movement therewith. The first drive member is independently rotatably associated with the camshaft. A piston member is axially moveably disposed within the camshaft interior passageway and associated with the camshaft for rotation therewith. The piston member is further associated with the first drive member for rotation therewith and axial movement relative thereto. Axial movement of the piston member effects a change in the angular position of the first drive member. In a second embodiment, a rotatable tubular member has an interior passageway. A first drive member connectable to one or the other of a crankshaft or camshaft for rotational movement therewith is independently rotatably associated with the tubular member. A second drive member connectable to the other of a camshaft or crankshaft for rotational movement therewith is rotatably fixed relative to the tubular member. The first drive member is independently angularly positionable relative to the second drive member. A piston member is axially moveably disposed within the tubular member interior passageway and associated with the tubular member for rotation therewith. The piston member is further associated with the first drive member for rotation therewith and axial movement relative thereto. Axial movement of the piston member effects a change in the angular position of the first drive member relative to the second drive member.

The present invention pertains to apparatus employed in the dynamic (i.e., during engine operation) adjustment of valve-timing in internal combustion engines as a means of optimizing engine performance, including power output, torque, and fuel efficiency.
Internal combustion, reciprocating piston engines, such as the conventional four-cycle (i.e., intake/compression/combustion/exhaust), single overhead camshaft engine 10 shown in simplified cross-section in FIG. 1, utilize one or more intake valves 11 to allow air or a mixture of air and fuel into the cylinder 20 for combustion, as well as one or more exhaust valves 12 to allow combustion gases to exit the cylinder 20 following combustion. The operation of these valves 11, 12 is sequenced in order to repeatedly charge the cylinder 20 with fuel and air either ahead of (in the case of four-cycle engines) or during (in the case of two-cycle engines) the piston's 25 compression stroke, and to repeatedly permit the discharge of exhaust gasses during the exhaust cycle. More particularly, the operational timing of these valves 11, 12 is controlled by a camshaft 30 rotatably connected (including, for example, a sprocket, chain, belt, etc.) via a geared linkage (not shown) to a rotating crankshaft 35 which supports and moves each piston 25 within its associated cylinder 20.
Still referring to FIG. 1, each of the intake 11 and exhaust 12 valves is biased to a closed position, as shown, by a spring 13 or other biasing means. Each of the intake 11 and exhaust 12 valves is further mounted on (or, alternatively, provided in contact with via, for instance, a lifter/push-rod linkage) a pivotable rocker arm 14 or 15, respectively, which rocker arms are positioned to selectively contact one of several corresponding cam lobes 31 axially disposed along the length of the camshaft 30. During rotational movement of the camshaft 30, a specific one of the cam lobes 31 will engage one of the intake 11 or exhaust 12 valve rocker arms 14 or 15, respectively, causing temporary pivoting movement of the rocker arm and, correspondingly, linear movement of the associated valve against the bias of spring 13 to its open position. Upon movement of the cam lobe 31 out of engagement with a valve 11 or 12, that valve is urged back to the closed position thereof by the biasing force of spring 13.
As those skilled in the art will appreciate, the timing or angular position of the camshaft 30 relative to the crankshaft 35 is critical in effecting engine performance. Moreover, such timing is not ideally constant through all engine speeds. Rather, it is preferable, for optimizing engine performance, that operation of the intake and exhaust valves be advanced or retarded in response to various engine operating conditions, including variations in torque, temperature, the fuel/air mixtures, engine speed, etc. Thus, a fixed camshaft—that is, a camshaft with an unchanging angular position relative to the angular position of the crankshaft—at best provides optimum engine performance only in a narrow range of engine operation.
To address this problem various means have been proposed, the most commonplace of which are apparatus for dynamically varying the angular position of the camshaft relative to the crankshaft to thus alter valve operation timing as appropriate to the engine's operating condition at a given time. The structure of such apparatus, also known as cam phasing devices or, more commonly, simply as cam-phasers, is exemplified in FIG. 2, adapted from the disclosure of U.S. Pat. No. 5,588,404, assigned to General Motors Corporation, and which disclosure is incorporated herein by reference in its entirety. In general, such cam phasers comprise a first rotatable element 50 mounted to the end of a camshaft 60 for synchronous rotational movement therewith. The first element 50 includes helical splines 51 on its outer surface. A second rotatable element 52 surrounds the first element 50 concentrically and has a drive member 53, such as a wheel, pulley, or sprocket, driven by the engine crankshaft (not shown). On an inner surface, the second element 52 is also provided with helical splines 54 arranged oppositely from the splines 51. A piston 55 is positioned between the first 50 and second 52 elements, the piston having helical splines on both inner and outer surfaces thereof, respectively, which splines mesh with one or the other of the splines 51, 54. Through axial movement of the piston 55, accomplished by controlled hydraulic pressure, the several splined surfaces cooperatively interengage to cause counter-rotation of the first 50 and second 52 elements relative to each other, thus changing the angular position of the camshaft 60 relative to the engine crankshaft.
Conventional cam phasers such as described are characterized by a number of drawbacks, including their relatively large dimensions, which necessitate larger engine compartments that translate to higher production costs. Conventional cam phasers also tend to have a relatively high mass, which adds to the rotational mass of the engine. Moreover, this mass is disposed outside of the bearing envelope of the camshaft, which disposition equates to additional stress on the camshaft as well as the mounting bearings the for. Finally, conventional cam phasers are characterized by a complex construction comprising numerous interrelated, individual components. This complexity increases manufacture and assembly costs, and further reduces the operating life of the apparatus.
It would, accordingly, be desirable to provide a cam phaser that overcomes the drawbacks associated with conventional cam phasers.

Dynamic valve timing adjustment mechanism for internal combustion engines


A securement device includes a filament which passes underneath at least a portion of the securement device and can be secured about a medical article to be retained. The filament may be secured about the medical article without the use of adhesive. At least a portion of the securement device underlying the medical article may comprise a compressible material which may be used to exert a restoring force upon the medical article to hold the medical article tightly in place.

1. Field
The present invention relates in general to a medical article securement device and more particularly, to anchoring devices for anchoring or securing medical articles relative to the body of a patient. In one mode, the present invention involves a medical article securement system that secures a medical article in place through the use of a filament.
2. Description of the Related Art
It is common in the treatment of patients to utilize catheters to introduce fluids and medications directly into the patient or to withdraw fluids from the patient. Often, it becomes desirable to maintain such catheterization over an extended period of time during the treatment of a patient. In order to keep the catheter or other medical article properly positioned for the duration of treatment, the catheter or medical article can be secured to the patient in a variety of ways. Most commonly, this involves taping or suturing the catheter or medical article to the patient.
Securing a catheter with tape upon the patient traditionally has certain drawbacks. The use of tape at the insertion site can retain dirt or other contaminant particles, potentially leading to infection of the patient. Tape also fails to limit catheter motion and, therefore, contributes to motion related complications like phlebitis, infiltration and catheter migration. Additionally, removal of taped dressings can itself cause undesired motion of the catheter upon the patient.
Taped dressings also require periodic changes. The frequent, often daily, removal and reapplication of adhesive tape to the skin of the patient can excoriate the skin. Such repeated applications of tape over the catheter or medical article can additionally lead to the build up of adhesive residue on the outer surface of the catheter or medical article. This residue can result in contaminants adhering to the medical article itself, increasing the likelihood of infection of the insertion site. This residue can also make the catheter or medical article stickier and more difficult to handle for healthcare providers.
Suturing also carries risk, both to healthcare workers and patients. Healthcare workers can suffer accidental needlestick injury, which may expose them to hepatitis, HIV, and other pathogens. Patients can suffer local or even systemic infection from suture, as well as scarring and pain.