Neural networks for optimal estimation (including prediction) and/or control involve an execution step and a learning step, and are characterized by the learning step being performed by neural computations. The set of learning rules cause the circuit's connection strengths to learn to approximate the optimal estimation and/or control function that minimizes estimation error and/or a measure of control cost. The classical Kalman filter and the classical Kalman optimal controller are important examples of such an optimal estimation and/or control function. The circuit uses only a stream of noisy measurements to infer relevant properties of the external dynamical system, learn the optimal estimation and/or control function, and apply its learning of this optimal function to input data streams in an online manner. In this way, the circuit simultaneously learns and generates estimates and/or control output signals that are optimal, given the network's current state of learning.

1. Field of the Invention
The present invention generally relates to neural networks, and more particularly, to recurrent neural networks for estimation (including prediction) and/or control.
2. Background Description
This invention is concerned with the problems of optimal, or approximately optimal, estimation and control. In a standard formulation of these problems, there is an external system or "plant" described at each of a plurality of times by a plant state that evolves over time according to a stochastic plant process, and there is a stochastic measurement process that produces measurements at each of a plurality of times. The optimal estimation problem consists of using the measurements to generate estimates of the plant states over time, so as to minimize a specified measure of the error between the estimated and actual plant states. The term "estimation" can refer to prediction, filtering, and/or smoothing, as described below.
The optimal control problem consists of using the measurements, or estimates thereof, to generate control signals that have the effect of altering the plant state in such a manner as to minimize a specified measure of the error between the actual and a specified desired (or target) plant state at one or more future times. A function, called the "cost-to-go", is typically specified. This function describes the cost of a process that generates and applies a succession of control signals to the plant, resulting in a succession of plant states over time. Given the current plant state or an estimate thereof, or a measurement vector that conveys information about the plant state, it is desired to generate a sequence of control signal outputs such that the cost-to-go is substantially minimized. The cost is typically a combination of terms that reflect the cost of generating control output actions, and the cost (or benefit, with a minus sign applied) of the plant state approaching or reaching a desired target state (or succession of such target states).
A classical method for treating optimal estimation and control problems is the Kalman filter or extended Kalman filter. The Kalman filter (KF) was first described in R. E. Kalman, Trans. ASME, Series D, Journal of Basic Engineering, Vol. 82 (1960), pp. 35-45. It solves the problems of optimal estimation and control when the plant and measurement processes satisfy certain conditions of linearity. The KF method also assumes knowledge of several types of parameters. It assumes that the deterministic portions of both the plant evolution (over time) process, and the measurement process (giving the relationship between the plant state and the measurement vector), are known; and that the noise covariances of both the plant evolution and measurement processes are also known. When the linearity condition is not strictly satisfied, the extended Kalman filter method (EKF) can be used to generate a linearized approximation of the plant and measurement processes. The EKF may be iteratively applied to obtain a sequence of linearized approximations. When the parameters of the plant evolution and measurement processes are not known, one can use a separate computation, "system identification", to determine or estimate these parameters.
Kalman Optimal Estimation and Control
The state of an external system (the "plant") governed by linear dynamical equations is described by a vector xt, which evolves in discrete time according toxt+1=Fxt+But+mt  (1)where the matrix F describes the noise-free evolution of x, m denotes an additive plant noise vector, u denotes an optional vector that may be generated as a control output signal by a controller system, and matrix B describes the effect of u on the plant state x. Sensors measure a linear function of the system state, with additive measurement noise n:yt=Hxt+nt.  (2)In classical Kalman estimation (e.g., the above-cited reference), it is assumed that the matrices H and F are known, and that the covariance matrices Q=Cov(m) of the plant noise, and R=Cov(n) of the measurement noise, are also known. Here E( . . . ) denotes expectation value, Cov(z)≡E[(z− z)(z− z)′], z is the mean of z, the prime symbol denotes matrix transpose, I will denote the identity matrix, and n and m are assumed to have zero mean.Kalman Estimation
The goal of the optimal estimation process is to generate an optimal estimate of xτ given a set of measurements {y1, y2, . . . , yt}. If τ is greater than, equal to, or less than t, the estimation process is referred to as prediction, filtering, or smoothing, respectively. An "optimal" estimate is one that minimizes a specified measure of the error between the estimated and the true plant state. Typically, this measure is the mean square error (MSE) of the estimated with respect to the true state.
Further notation and definitions are as follows. The a priori state estimate is {circumflex over (x)}t−≡{circumflex over (x)}(t|y1, . . . , yt−1), where the right-hand side denotes the estimated value of xt given the values of {y1, . . . , yt}. The a posteriori state estimate is {circumflex over (x)}t≡{circumflex over (x)}(t|y1, . . . , yt). The expressionηt−≡(yt−H{circumflex over (x)}t−)  (3)is called the measurement "innovation" or "residual", and is the difference between the actual and predicted (in the case that τ=t+1) measurements at time t. The a priori and a posteriori state estimate errors are, respectively, ξt−=xt−{circumflex over (x)}t− and ξt=xt−{circumflex over (x)}t, and the covariances of these respective errors are pt−=Cov(ξt−) and pt=Cov(ξt). Since the estimation algorithm does not have access to the actual state xt, pt− and pt are not directly known. They are iteratively estimated by the algorithm below, starting from arbitrary initial values; these estimates at time t are denoted by (capital) Pt− and Pt respectively.
Kalman's solution for the optimal filter (i.e., the case τ=t) is then described by the following procedure: Given arbitrary initial values for {circumflex over (x)}0 and P0 (P0 is however typically initialized to be a symmetric positive-definite matrix), iteratively compute for t=1, 2, . . . :{circumflex over (x)}t−=F{circumflex over (x)}t−1+But−1  (4)Pt−=FPt−1F′+Q  (5)Kt=Pt−H′(HPt−H′+R)−1  (6){circumflex over (x)}t={circumflex over (x)}t−+Ktηt−={circumflex over (x)}t−+Kt(yt−H{circumflex over (x)}t−)  (7)Pt=(I−KtH)Pt−(I−KtH)′+KtRK′t.  (8)
Combining Eqs. 5 and 8 yieldsPt+1−=FPt−F′+Q−FKt(HPt−H′+R)K′tF′.  (9)This iterative solution may be regarded as consisting of two parts: an execution step during which a new estimate is computed (Eqs. 4 and 7) using an estimation function (here, Kt or (I−KtH), which are related to Pt−); and an updating step during which a new estimation function is generated (Eqs. 6 and 9) in terms of an estimation function at a previous time.
The solution for the optimal prediction problem with τ=t+1 is given by the same equations, using Eq. 4 to generate the optimal prediction {circumflex over (x)}t+1− given measurements through time t.
One extension of classical Kalman filtering, as noted above, is the extended Kalman filter (EKF) method. This can be used when the linearity conditions above are not strictly satisfied. EKF can be used to generate a linearized approximation of the plant and measurement processes, and may be iteratively applied to obtain a sequence of linearized approximations. The resulting solution is not strictly optimal in general, but only approximately so. The Kalman equations can also be generalized by allowing one or more of the matrices H, F, R, and Q to be functions of t. Also, when the parameters of the plant evolution and measurement processes are not known, one can perform a separate computation, "system identification", to determine or estimate these parameters.
Kalman Control
We turn now to optimal Kalman control. The stochastic linear quadratic Gaussian (LQG) control problem can be described as follows, in the case of "full observability" (i.e., where the plant state vector xt at each time is assumed known). From a current plant state xtcurr at time tcurr<N, it is desired to optimize a set of control output signals {utcurr, utcurr+1, . . . , uN−1}. The trajectory of the plant state—that is, the sequence of states {xtcurr+1, . . . , xN}—will depend on the choice of the u values, on the initial state xtcurr, and on the noise terms {mtcurr, . . . , mN−1}.
The quantity to be optimized is called the "cost-to-go", and has the following form. The cost-to-go of the trajectory comprises a control-action cost u′tgut and a target-deviation cost x′trxt for each time step t from tcurr to N, where both g and r are specified symmetric positive-definite matrices. Thus the cost-to-go, denoted J, is
                    J        =                                            ∑                              t                =                tcurr                                            N                -                1                                                                                (                                                                    u                    t                    ′                                                                          gu                    t                                                  +                                                      x                    t                    ′                                                                          rx                    t                                                              )                                +                                    x              N              ′                                                                  rx                N                            .                                                          (        10        )
The optimization problem consists of determining the set of values of u for which the value of J, averaged over initial position xtcurr and plant noise, is a minimum. The solution has the form ut=−Ltxt, where L is the Kalman control matrix at time t.
In one extension of the above formulation, at least one of the matrices g and r may be functions of t. Also, the cost-to-go function may include additional cross-terms involving both x and u. See, for example, the University of Lund (Sweden) online lecture notes at http://www.control.lth.se/˜kursdr/lectures/f13LQsynth.pdf. Also, the cost-to-go may be described in terms of a desired target state xtarg, in which case each xt in Equation 10 should be replaced by xt−xtarg. In that case, the target state may itself vary with time, as for example in the case that the goal is to generate control signals so that the plant state xt may approximately follow a desired target trajectory.
In certain special cases, the cost-to-go may be formulated in such a way that the optimal matrices Lt are independent of time. This is referred to as a "stationary" optimal control problem. In one such case, the final time t=N is considered to be effectively infinite. In another such case [see, e.g., Szita and Lörincz, Neural Computation, vol. 16 (2004), pp. 491-499], the final time t=N is considered to be indeterminate; i.e., if the cost-to-go terms have not terminated by an arbitrary time step t, they are assumed to terminate at the next time step t+1 with a given constant probability.
For the optimal control problem stated above, the classical Kalman solution is described by the following procedure, where S is an auxiliary matrix that is a function of t. Starting with SN=r, iteratively compute for the decreasing sequence of time index values t=N, N−1, . . . , tcurr:Lt=(B′StB+g)−1B′StF  (11)St−1=F′StF+r−L′t(B′StB+g)Lt.  (12)Then, for t=tcurr and (optionally) for later t, use the Kalman Lt matrices to compute the control vectors ut:ut=−Ltxt  (13)
This process generates the set of optimal control output vectors {utcurr, . . . , uN−1}. As in the case of estimation, but with a key difference (regarding the order of computation of functions having different values of the time index), this iterative solution may be regarded as consisting of two parts: an execution step during which a new control vector is computed (Eq. 13) using a control function (here, Lt, which is related to St); and an updating step during which a new control function is generated (Eqs. 11 and 12) in terms of a control function that is associated with a later time index.
Note that, as observed by Kalman, the solutions to the optimal estimation and control problems are mathematically "dual" to one another. Equations 11, 13, and 12 are related by this duality to Equations 6, 7, and 9 of the Kalman filter solution, respectively. As noted above, however, the S and L matrices of the control problem are iteratively computed from later to earlier time index values (i.e., "backward in time"), whereas the P− and K matrices of the filtering problem are computed "forward in time". The Kalman filter matrix K can therefore be computed at time t and immediately applied to determine the optimal a posteriori state estimate {circumflex over (x)}t, whereas the Kalman control matrices Lt must first be computed for a sequence of decreasing time index values, before they can be applied at the current time t=tcurr and then at later times.
Artificial Neural Networks
An artificial neural network (ANN) is characterized by processor nodes and connections between them, each node and connection typically being capable of performing only relatively simple computations, wherein the behavior of the nodes and connections is described by parameter values which either may be fixed or may be modifiable according to a specified learning or update rule. Some of the parameters describing the connections are referred to as connection "weights" or "strengths". An ANN may be implemented either in hardware, or as software that is run on a general-purpose computer. A processor node is a computation unit (in hardware) or a simulation of such a unit (in software), wherein at least one input value is transformed into at least one output value. Typically the node computes, as its output, a specified function (which may be nonlinear) of the sum of its input values. Each input value or "activity" is typically described by a numerical value that may be time-varying. Time may be continuous-valued or may consist of discrete time steps. In a hardware implementation, an activity may be represented by any of a variety of signals, e.g., a level of, or change in level of, a current, voltage, or other physical quantity, wherein the magnitude, timing, and/or repetitive nature of the level or change carries the information. A processor node may be an internal node of the network (connected only to other nodes of the network), or may be a sensor or input node (providing or transducing information from the external environment to the network), or may be an effector or output node (generating signals from the network that influence the external environment).
Each connection conveys an activity value from one processor to another. The connection may be passive (i.e., may just transmit the value unchanged from one processor to the other) or may be active (transform the value en route). In the latter case, the particular transformation is specified by at least one parameter. Typically the transformation consists of a simple multiplication of the activity value by the connection strength.
Neural network computations are often described in terms of the behavior of a set of related nodes and connections. Suppose that there are two sets of nodes, one set of which (the source nodes) provides input to the other set (the target nodes). An activity vector, for example z=(z1, z2, . . . , zn), at a given time represents the fact that the activity at node k is equal to zk at that time. (Note that here the superscripts denote index values, not exponents.) A matrix C refers to a set of connections from source to target nodes, where Ckj is the strength of the connection from node j to node k. In the case that each target node simply computes the sum of its weighted inputs, then a target activity vector z is related to a source activity vector v by the matrix equation z=Cv, which represents the set of equations zk=ΣjCkjvj. If the kth target node computes a nonlinear function gk of the sum of its inputs, then we have instead zk=gk(ΣjCkjvj).
In an ANN, connection weights may be "directed", meaning that Cji and Cij correspond to different connections (from i to j and from j to i respectively), and (if both connections exist) have strengths that need not be equal; or "undirected", meaning that the two strengths are required to be equal to each other.
A layered ANN is one in which the nodes are organized into two or more groupings (called layers, but in the present invention not implying any particular geometric arrangement). Within a layered network, the connections may be within (a) a single layer (lateral connections), (b) from a "lower" to a "higher" layer in a hierarchy (feedforward connections), and/or (c) from a "higher" to a "lower" layer (feedback or recurrent connections). A layered ANN with recurrent connections is also called a recurrent neural network (RNN).
Adjustable connection strengths, and other adjustable parameters, may be modified using a learning rule. Typically, a learning rule is "local", meaning that the rule makes use only of activity values, connection strengths, and other parameters or state information that are available at the node or connection being modified. For example, a simple version of a "Hebbian" learning rule changes a strength Cji by an amount proportional to the product of the activities zi and zj at either end of the connection from i to j. In some cases, a learning rule may make use of certain global values or signals that are available at all, or a subset of, the nodes and connections. For example, in a "reinforcement learning" algorithm, the change in strength may be proportional to a quantity that represents the overall benefit or cost resulting from an output signal produced by the network at a previous time step.
Also, in some cases, a subset of corresponding connections may be considered to be coupled or "ganged" together, so that they all have the same connection strength, and are all modified in tandem by the average of the amounts by which each such connection would have been modified if they were not so coupled. For one example of a network computation using ganged connections, see S. Becker and G. Hinton, Nature, vol. 355, pp. 161-163 (1992). This may be done either to speed up a computation (as in the above reference), or to cause corresponding parts of a network to behave in a coordinated manner.
Other types of ANNs and learning rules have been described in the literature; for a good introduction, see J. Hertz, A. Krogh, and R. G. Palmer, Introduction to the Theory of Neural Computation, Addison-Wesley 1991. As one example, the information conveyed between nodes of an ANN may be carried by the precise timing of spikes (rapid changes in activity value) rather than by the numerical value of the activity itself. As a second example, another type of ANN is a "radial basis function" (RBF) network. The output of an RBF node decreases as a function of the distance between the set of inputs to the node (regarded as a vector) and a "prototype vector" that is stored as a set of parameters for that node; the prototype vector is typically modified according to an appropriate learning rule.
Use of ANNs in Estimation and Control Problems
Typically, an ANN is used to perform an estimation function (such as prediction) by a process of "supervised learning", using a training set comprising both measurement values and the desired plant state values to be estimated. The network parameters (e.g., the connection strengths) are initialized, a set of measurement values is presented as input to the ANN, a set of output values is generated by the ANN, a measure of the error between the ANN's output and the desired output (the plant state at a given time) is computed, that error measure is used to modify the connection weights (and other adjustable parameters, if any) of the ANN according to a specified learning algorithm such as the "back-propagation" algorithm, and the process is iteratively repeated with a new set of inputs. The ANN's weights may thereby converge to values that cause the ANN to generate outputs whose error measure is sufficiently small.
To treat the control problem, an ANN is typically used to generate one or more control outputs whose values depend upon the measurement inputs and the ANN's weights; the control outputs act on the plant (or on a simulated model of the plant) to alter the plant state; a measurement (or computation) of the new plant state is used as the new input to the network; and a measure of the error between the measured plant state and the target plant state is computed and used to modify the ANN's weights in accordance with a learning algorithm.
Standard methods for training the weights of a recurrent neural network (RNN) based on time sequences of input values and desired output values include "real-time recurrent learning" and "back-propagation through time", both of which are described in Hertzet al., ibid., pp. 182-186.
J. T. Lo, in U.S. Pat. Nos. 5,963,929 and 5,408,424, describes the use of an RNN for optimal or near-optimal filtering (a form of estimation). In the '929 patent, a "recursive neurofilter" is used to estimate a signal process with respect to an estimation error criterion, where at least one weight is a nonlinear weight and is adjusted during a separate training process. Also described is the use of a second "neurofilter" (a second circuit or algorithm), to produce an approximation of the statistical error of the estimates. In both the '929 and '424 patents, the neural network is trained using pairs of inputs—measurement data and the actual state of the plant—as discussed above. These pairs are used to train the connection strengths in a generic RNN (see col. 42 of the '424 patent specification). The patent relies on the general knowledge of "supervised learning" methods in the ANN field, regarding how to learn to match actual output with desired output, in order to train the weights. Note that information about the actual plant state is required for operation of this method. In practice, however, one may only have access to measurement data, and not to the plant state itself, preventing one from using this method. Note also that: the adjustable weights are kept fixed during operation of the network (that is, those weights are not being learned or adjusted while the filter is actually performing its estimation of a signal process); the second "neurofilter" is distinct from the first "neurofilter" and although Kalman estimation is discussed as an alternative estimation method, Kalman estimation is not involved in the networks described (i.e., the networks neither learn nor use Kalman estimation).
Neural networks have been used in conjunction with the Kalman estimation (also referred to as the Kalman filter, or KF) equations in several ways.
First, the KF or EKF equations have been used to compute how the weights in an ANN should be modified. The ANN weights to be determined are treated as the unknown parameter values in a system identification problem, sets of input values and desired output values are specified, and the KF or EKF equations are used to determine the ANN weights based on the sets of input and desired-output values. The equations are solved by means of conventional mathematical steps including matrix multiplication and inversion. That is, the weights are not computed or updated (learned) by means of a neural network. Instead, the weights are read out from the neural network, provided as input arguments to the KF or EKF algorithm (which is not a neural network algorithm), the updated weight values are then provided as outputs of the KF or EKF algorithm, and the updated weight values are then entered into the neural network as the new weight values for the next step of the computation. For examples of this combined usage of an ANN in conjunction with the classical KF or EKF equations, see: S. Haykin (ed.), Kalman Filtering and Neural Networks, Wiley-Interscience, 2001, and in particular the chapter by G. V. Puskorius and L. A. Feldkamp; S. Singhal and L. Wu, "Training Multilayer Perceptrons with the Extended Kalman Algorithm", in D. S. Touretzky (ed.), Advances in Neural Information Processing Systems, vol. 1 (Morgan Kaufmann Publ., San Mateo Calif., 1989), pp. 133-140; R. J. Williams, "Training recurrent networks using the extended Kalman filter", in Proceedings of the International Joint Conference on Neural Networks, June, Baltimore, Md., Vol. IV (1992), pp. 241-246; and I. Rivals and L. Personnaz, "A recursive algorithm based on the extended Kalman filter for the training of feedforward neural models", Neurocomputing, vol. 20 (1998), pp. 279-294.
Second, one can combine the output from a nonlinear ANN with that of a (non-neural) KF algorithm, to improve predictions when applied to a nonlinear plant process. See for example Klimasauskas et al., "Hybrid linear—neural network process control", U.S. Pat. Nos. 6,278,962 and 5,877,954. This method involves two analyzers: a primary "data-derived" one that generates a primary output, and a secondary "error correction analyzer" that generates a predicted error output; then the two analyzers' outputs are summed. Here the NN weights are trained to minimize the difference between (a) the sum of the linear filter output and the NN output, and (b) the desired output (e.g., the actual signal vector). That is, the NN learns how the linear filter output differs from the actual signal (or the desired output), and attempts to compensate for that difference. Here the NN does not learn a Kalman filter (KF); the KF is used alongside the NN, and the two perform complementary tasks. The KF is not computed or learned by means of a neural network or a set of neural computations. A similar combination is used in Tresp et al., "Method and arrangement for the neural modelling of a dynamic system with non-linear stochastic behavior", U.S. Pat. No. 6,272,480. This method combines the output of a nonlinear recurrent neural network (RNN), with an error measure (based on a linear-equation model of the system error) that is modeled using a KF, in order to alter the RNN. The KF equations are not implemented within a neural network. They are solved, e.g., using a conventional computer program, and their values are then used to adjust the neural network's behavior.
Third, an ANN learning rule has recently been described that is motivated by the KF equations, although it does not implement the learning of a KF within an ANN. See G. Szirtes, B. Póczos, and A. Lörincz, in Neurocomputing, vols. 65-66 (2005), pp. 349-355. In this method, the KF equations are first altered in several ways. One of these alterations replaces the matrix product HK, where H is as in Eq. 2 and K is the KF matrix, by the identity matrix I. This assumption that HK is approximately equal to I is, however, not valid in general, but only under special conditions. Another of these alterations neglects the off-diagonal terms in a matrix that is being updated. This alteration is stated to be justified when the estimated plant process satisfies an assumption of "independent component transformation". For this assumption to hold, special preprocessing steps are in general required. Another alteration neglects a "self-excitatory" contribution. Yet another alteration introduces a random vector in order "to provide a conventional neuronal equation", but this alteration incorrectly changes a significant term in the learning equation, so that the contribution of that term is averaged to zero. These alterations cause the resulting "learning rule" to fail to learn a KF matrix, even approximately. Furthermore, results displayed in that reference show a decreasing estimation error. However, the decrease shown is not the result of an approximation to a KF matrix having been learned. Similar results are obtained even when an arbitrary matrix K is used (instead of using an approximation to the KF matrix), with no learning at all taking place. For these reasons, this method does not implement the learning of a KF within an ANN.
A classic formulation of the optimal control problem is Bellman's method of dynamic programming, in which (at each time step) a system has a set of allowed transitions from each state to a set of other states. A cost is associated with each transition, and the problem is to determine an optimal or near-optimal control policy that governs which transition to choose when in each state, to minimize an overall cost function. A class of ANN algorithms, based on "temporal difference" (TD) learning (a form of reinforcement learning) and its extensions, has been developed to learn the transition costs and a control policy. For a reference on TD learning (and reinforcement learning more generally) see: R. S. Sutton and A. G. Barto, Reinforcement Learning: An Introduction, MIT Press, 1998.
For the more specialized case of a linear quadratic Gaussian (LQG) system, or for a linear quadratic (LQ) deterministic system, the optimal Kalman control (KC) solution is as discussed above. The general KC solution has not been implemented within an ANN. However, a solution of a particular specialized form of the LQG control problem, namely, the "stationary" optimal control problem discussed above, has been implemented using an ANN with a TD learning rule (Szita and Lörincz, loc. cit.). In this special case, as noted above, the cost-to-go terms are assumed to terminate at any future time step with a given constant probability.

Neural networks for prediction and control

International Business Machines Corporation


The semiconductor integrated circuit capable of reducing an interconnection width as compared with conventional one while suppressing electromigration effectively. An input unit 101 stores interconnection information in an interconnection information storage unit 104. An arithmetic operation unit 102 acquires the interconnection information upon accessing the interconnection information storage unit 104 and acquires an arithmetic operation parameter while accessing the arithmetic operation parameter storage unit 105 to determine a width W of the interconnection based on these values. That is, the width W of the interconnection is made to determine upon multiplying (current i)1/3 by the arithmetic operation parameter (constant), which current is caused to flow through the interconnection.

1. Field of the Invention
The present invention relates to a semiconductor integrated circuit, a method for designing semiconductor integrated circuit and a system for designing semiconductor integrated circuit.
2. Description of Related Art
It is known that, when the current is continuously caused to flow through the metal interconnection of the semiconductor integrated circuit, disconnection or resistance degradation of the interconnection takes place depending on phenomenon of metal element transportation called as an electromigration.
When the current is caused to flow through the metal interconnection of the semiconductor integrated circuit, electron of electron flow and metal atoms collide. The electromigration is phenomenon where the metal atoms move in the direction of electron flow while receiving stress caused by momentum exchange on the occasion of the collision between electron of electron flow and metal atoms.
Porosities are accumulated in upstream of the electron flow caused by migration of the metal atom. A large amount of accumulated porosities form a hole called as an optically observable physical void. The void grows in the interconnection. There occurs such problems as electrical conductivity is lost; defect takes place in transmission of signal while increasing interconnection resistance, or the like in the interconnection where the void grows in certain degree of size. Also, it is known that an acceleration factor of this electromigration is current density and atmospheric temperature.
A service life of the interconnection deteriorates caused by the electromigration. In order to compliance with this interconnection life degradation, so far particularly restriction of the drive current has been adopted to cope with the degradation of the service life. As described in paragraph "0002" of the Japanese Laid-Open Patent Publication No. HEI 07-21246, required minimum line width of the conventional interconnection is designed in such a way that the required minimum line width increases directly proportional to the current amount caused to flow.
By applying this concept, an interconnection is formed on a semiconductor substrate with a damascene method. FIG. 3 is one which represents the interconnection width with current caused to flow through this interconnection in every service life of 5 years, 10 years, 15 years and 20 years. From this drawing, for instance, in the case that current of 0.1 mA is caused to flow through the interconnection with interconnection width: W=0.1 μm and the service life: 10 years; so, when current of 0.2 mA is caused to flow through the interconnection, this proves that it is necessary to design width W of the interconnection W=0.2 μm.
The semiconductor integrated circuit, which is designed in such a way as above conventional concept, increases the interconnection width directly proportional to increase of the current caused to flow through the interconnection. Accordingly, when being caused to flow large current, there has been the problem that a chip area becomes large. In particular, when the service life of the interconnection is long and the large current is caused to flow, there is the problem that extremely large chip area is necessary.

Semiconductor integrated circuit, method for designing semiconductor integrated circuit and system for designing semiconductor integrated circuit


A tool for assembling a union comprising first and second nuts for joining two tubing segments is disclosed. The tool includes a first and a second leg pivotally connected for scissor-like movement, each leg having an anti-torque engagement member associated with an anti-torque formation on a respective one of the nuts and tubing segments.

Especially, but not exclusively in the field of piping of hazardous gases, it is customary to couple adjacent lengths of tubing by means of a compression-type union. Such tubing is generally made of a strong corrosion resistant metal, and each segment terminates at a hard peripheral sealing surface.
These beads are opposed to one another across a sealing washer. Compressive coupling means comprising a pair of threaded-together nuts forces the segments toward the washer so as to indent the seals into the washer to make a fluid seal. The nuts bear against respective shoulders on the segments, and the segments project through central passages in the nuts.
The objective of these unions is to compress the two beads against the washer as a stack. A union of this type has been in widespread usage for many years, exemplified by Callahan U.S. Pat. No. 3,521,910, whose status approaches that of a standard in the industry. In one of its most commonly-encountered applications, it is used to couple segments of metal tubing used in chemical process equipment--for example in chip manufacturing installations, where it is referred to as a VCR (vacuum compression rad) union. For purposes of making a highly reliable fluid tight seal between the tubing segments, it is at least potentially fully adequate and is widely used.
The VCR fitting requires that the two beads be tightened down against the washer as the consequence of a combined rotary and axial motion derived from tightening the threads which join the two nuts. If the ends of the tubing segments removed from the union are free to rotate, there is no problem. However, this is usually not the situation. Instead, these tubing segments are customarily already rigidly connected to some next element. As a consequence, rotation of the tubing segments caused by tightening of the union results in deformation of the segments as a consequence of what had also become a twisting force. What is intended to be a neat assembly turns into a group of randomly distorted tubing segments. This presents a less-than-professional appearance for what is often a high-cost piece of capital equipment.
Worse still is the fact that this deformation stores restorative energy tending to loosen the union. Considerable care must be taken to assure that the union is tight enough to prevent this. Even so, events such as earthquakes cause concern that such unions might become loose.
Attempts are made, of course, to attempt to avoid these consequences. Careful installation can at least reduce the risk, and thrust washers have been suggested as a means to reduce the rotational forces exerted on the beads. Such arrangements add complexity and expense to a unit which ought to be kept as elegantly simple as possible.
Efforts have been made to place in the union itself some means to prevent relative rotation. A very old example is shown in Vail U.S. Pat. No. 748,546, and a more recent one is exemplified by applicant's own union sold commercially as the ZTNut by Exel Company 2450 Oak Street, Suite E, Santa Monica, Calif. 90405. There are others. These provide a splined article whose intent is to prevent undesired relative rotation in the union.
The efforts to improve over Callahan have had varying success, and always cost more because of the additional machining and parts they require. Applicant's ZT Nut does closely approach the ultimately desired lack of torque and non-galling sealing surfaces, but at a price. Other known attempts to solve the problems involve both additional cost and lesser performance, such as permitting independent rotation of the tubing segment.
It is an object of this invention to provide a tool, and the combination of a conventional union and this tool, which can provide the ultimate objectives without additional cost for the union, because with this invention the simple conventional device can be installed to the ultimate specifications.
It is an object of this invention to provide a simple union in which the bead seals, while being tightened, are exposed only to axial compressive sources, and neither they nor their tubings rotate relative to the washer or to each other during assembly, nor can they be independently rotated after assembly. The objections to the conventional union are thereby entirely overcome, and this is done with a simple tool.


A digital trunk for in-band line signals, which is capable of performing the local loopback test to verify not only the normality of the digital trunk but also the normality of the operation of upper hierarchy control devices, on-line software controlling the digital trunk and office data, is realized by only adding a small quantity of hardware of signal droppers and signal inserters. The digital trunk has a line signal sender and a line signal receiver of 32 channels and is provided with signal inserters and signal droppers for looping a speech channel at the time of the loopback test of the trunk. Furthermore, signal inserters and a multiplex circuit are provided for looping an in-band line signal. Time slots 0 and 16 which are usually unused as speech channels on the digital circuit are used as an opposed channel and a reserve channel for a loopback test, respectively, and the loopback test of the local trunk is performed.

1. Field of the Invention
The present invention relates to a digital trunk which is used in a digital electronic exchange to perform in-band (voice frequency band) line signal control, and more particularly, to a digital trunk including a local loopback test capability for an in-band line signal circuit by on-line call processing.
2. Description of the Related Art
Generally, digital electronic exchange, using an in-band line signaling system as one of line signaling systems, is provided with a digital trunk for controlling the in-band line signal, and the loopback test of the in-band line signal circuit is suitably to be performed to maintain normality of the in-band line signal circuit.
A technique on the loopback test of the in-band line signal circuit such as this is mentioned, for example, in Japanese Patent Application Laid-Open No. Hei 5-95410.
FIG. 1 is a block diagram showing a technology of the loopback test of the in-band line signal disclosed in the Japanese Patent Application Laid-Open No. Hei 5-95410.
The digital electronic exchange is provided with a central control 101, a time division switch 102, a multiplexer/demultiplexer 103 and a digital trunk 104, and the multiplexer/demultiplexer includes a multiplex/demultiplex circuit 131, an in-band signal transmitter 132, an in-band signal receiver 133 and a control unit 134.
In an ordinary call processing, the in-band line signal is received by the in-band signal receiver 133 through the digital trunk 104 and the multiplex/demultiplex circuit 131 which multiplexes all incoming signals. The in-band signal receiver 133 transfers the received in-band line signal to the central control 101 via the time division switch 102 for call processing purposes, and also transfers to the control unit 134 for detecting idle condition or busy condition of each time slot and classifying each signal. When the loopback test is performed, the control unit 134 detects idle time slot, and instructs the multiplex/demultiplex circuit through control line 137 to connect an incoming line 135 and an outgoing line 136 corresponding to the idle time slot having been detected. Then, the in-band signal is transmitted from the in-band signal transmitter 132 and received by the in-band signal receiver via loopback established in the multiplex/demultiplex circuit 131, and normality of the signal is confirmed.
Hitherto, in the case where the local loopback test of a digital circuit with the in-band line signal is performed in the exchange, there is another method where the transmission-reception test of the in-band line signal is performed with a transmission time slot (TS) to a circuit, as it is, returned back to the same TS on the reception side, because a line signal channel for call control and a speech channel use the same circuit, and the normality of the signal channel and speech channel is confirmed at the same time.
Furthermore, when performing the local loopback test of the digital circuit provided with in-band line signals, there is also a method where TS (not being occupied) in an idle state is detected and a transmission-reception looping test is made only for an in-band line signal which corresponds to the aforementioned TS (the transmission TS number and the reception TS number are the same).
The aforementioned loopback test, incidentally, has the following problems.
First, in the conventional loopback test, the TS on the transmission side, as it is, is simply returned to the same TS on the reception side at the time of the loopback test and transmission and reception of the signal is only confirmed. Therefore, there is the problem that the call processing sequence with the opposite exchange cannot be simulated and that the normality of a part of control hardware involved itself can only be verified but the normality of other relating parts, such as the operation of an upper hierarchy control device, on-line software and the office data, cannot be verified.
Furthermore, at the time of the loopback test, the tested circuit cannot be used for ordinary call. Therefore, it is problem that the number of circuits provided for the opposite exchange is decreased.


The present disclosure is directed to generating animated images for presentation by a dynamic keyboard interface. In particular, the methods and systems of the present disclosure can: receive data describing advertisement content, and data describing a first context in which to present the advertisement content; generate data describing a first animated image including at least a portion of the advertisement content; determine a second context in which to present the advertisement content; generate data describing a second animated image including at least a portion of the advertisement content; and communicate, to one or more user devices on which one or more applications are executed, data indicating a plurality of different animated images for presentation by a dynamic keyboard interface in association with the one or more applications, the plurality of different animated images comprising the first animated image and the second animated image.

Computing devices (e.g., desktop computers, laptop computers, tablet computers, smartphones, wearable computing devices, and/or the like) are ubiquitous in modern society. They can support communications between their users, provide their users with information about their environments, current events, the world at large, and/or the like. A myriad of different types of interfaces enable users to interact with such devices. For example, many devices include a touchscreen and provide an interface (e.g., including user-selectable options, a keyboard, and/or the like) configured to enable users to input information. Animated images (e.g., graphics interchange format (GIF) images, and/or the like) can include data describing a series of ordered image frames that when rendered produce a moving image, and/or the like. Animated images can be utilized to express, convey, communicate, and/or the like thoughts, feelings, concepts, emotions, and/or the like.

Methods and systems for generating animated images for presentation by a dynamic keyboard interface


The present disclosure describes systems, non-transitory computer-readable media, and methods for generating a visual media collection for a social networking account and provide access to (or distribute) images, videos, or other visual media items from the visual media collection separate from social networking posts uncategorized within such a collection for the social networking account. For example, based on follow requests specific to a visual media collection, the disclosed systems can further distribute visual media items in collections posts from a particular visual media collection differing from other visual media collections and from social networking posts uncategorized within such a collection of a social networking account. In certain implementations, the disclosed systems further provide search results comprising a visual media item from a visual media collection based on a description or annotation for the visual media collection or a shared visual media collection with another visual media item.

Content-sharing systems increasingly post and distribute visual media from network users across the Internet. Indeed, some content-sharing systems currently provide options for users to post communications with still digital images, videos, or other visual media captured by or downloaded by a personal computing device, such as a smartphone. In some instances, a content-sharing system distributes visual media from one user to the user's followers within the content-sharing system.
Various users leverage content-sharing systems to more easily distribute visual media to target audiences interested in particular topics. But conventional content-sharing systems often limit users to curating and distributing content feeds focused on a particular topic, such as a board of posts with a particular theme. Conventional topic-limited-content feeds silo content-sharing systems into a rigid organization and consequently isolate users into subscribing to fixed content feeds and sometimes to subscribing to another user's content feeds containing posts of topics irrelevant to the subscribing user.
Due to the high volume of visual media in content feeds, many conventional content-sharing systems present graphical user interfaces that require a large number of interactions for a user to locate a particular image, video, or other visual media item. For example, some conventional content-sharing systems require that a user download a visual media item to locate the visual media item at a later time. But such downloading is an inefficient use of client device storage. Further, conventional content-sharing systems requiring such downloads often force a user navigate out of a content-sharing application to view the downloaded visual media.
Additionally, some conventional content-sharing systems require that a user utilize a search function to re-locate a particular visual media item. But locating visual media through search terms often requires many searches and scrolling through many visual media items. Conventional content-sharing systems thus require an undue number of interactions across multiple graphical user interfaces to locate visual media items. Such repeated searching and scrolling wastes system and client device computing resources.
Accordingly, many conventional content-sharing systems limits content feeds to a rigid organizational structure, lack suitable mechanisms for re-locating and viewing particular visual media items, and make inefficient use of system and client device storage and computing resources.

Generating visual media collections for a dynamic social networking account


The invention relates to polymer compositions which enable thermooptic control of signal attenuation in the ultraviolet, visible and near infrared (NIR) regions of the electromagnetic spectrum, and devices incorporating such compositions. The compositions are derived from polymer mixtures which exhibit a cloud point phase transition at a temperature in the range of a thermooptically controlled device such as a programmable waveguide attenuator, a programmable neutral density filter, or an optically absorbent switch. An especially preferred embodiment of the invention comprises a mixture of a high molecular weight chlorotrifluoroethylene fluid and a wax with an “ON-state” insertion loss of below 0.1 dB/cm and an extinction ratio of 22 dB/cm in the 1550 nm NIR telecommunication band.

The present invention relates to the field of thermooptically active materials used in optical components and technology. More particularly, the present invention relates to the fields of optical waveguides, optical filters, optical switches, laser optics, neutral density filters, optical attenuators, flat panel displays, and projection display devices.
A persistent difficulty in the field of optical polymer materials is the high attenuation of such materials when they are in their inactive, or maximally transmissive state, sometimes denoted the "ON-state". For example, many polymer plastics have been developed for use in passive optical waveguides for telecommunication signals in the near infrared (NIR), particularly at 1300 nm and 1550 nm. Even though such polymers are intended to be optimally transmissive at all times (i.e. always in their ON-state), attenuation levels of up to 0.5 dB/cm are typical for conventional "low loss" materials. The absorption in such polymers is usually due to the presence of carbon-hydrogen bonds that exhibit strongly absorbing anharmonic vibrational resonance overtone bands in the NIR. The halogenated analogs of carbon-hydrogen polymers, wherein the hydrogen is substituted by a higher mass halogen such as fluorine, bromine, iodine, or chlorine, exhibit much weaker NIR absorption and are therefore more highly transmissive. Halogenated polymers have been tested as passive waveguide media that exhibit improved attenuation levels of under 0.1 dB/cm. In an embodiment of the present invention, preferred for applications in the NIR, the composition comprises halogenated polymers in order to realize low attenuation.
So-called "active" polymers are used in optics in order to manipulate characteristics of optical signals by means of external control inputs, which affect the optical properties of the polymers. The polymer compositions are suitable for use in thermooptically active optical components because of their large thermooptic coefficient for the index of refraction, dn/dT, or rate of change of refractive index with temperature. In an example of an electro optically active polymer composition for use in an optical component, radio frequency (rf) electrical control inputs, rather than thermal inputs, are used to allow high-speed phase modulation of optical signals propagating within the polymer. An important figure of merit for any such actively controlled polymer medium is that it have minimal total absorption when switched to the ON-state. Ideally, it will have the best achievable ON-state absorption performance for the passive polymer media mentioned above, or a figure of merit, usually denoted in the art as "insertion loss", of less than 0.1 dB/cm.
The expected absorption for the prior art electrooptically controlled chromophoric polymers is at least 10 dB for a 1 cm active polymer length or an insertion loss of 10 dB/cm. These materials, when used in a Mach-Zehnder interferometer configuration can provide a maximum absorption in the OFF-state of 30 dB. The difference in these two attenuation levels is a second important figure of merit for any switched medium, denoted the "extinction ratio". In this case, the difference between the maximum OFF-state absorption and the minimum ON-state absorption yields an extinction ratio of 20 dB. Since their device has an active polymer length of 1 cm, their extinction ratio per unit length is 20 dB/cm. Extinction ratio performance for the present invention was measured to be 22 dB/cm, a level equal to or improved over prior art media.
Other optical switches described in the prior art are comprised of thermooptically controlled polymer materials that exhibit insertion loss of 0.6 dB/cm and are limited to an extinction ratio of 20 dB total. In the prior art, U.S. Pat. No. 6,208,798 discloses a polymer cladding that is thermooptically controlled to permit leakage and hence attenuation of optical signals from the waveguide core; a preferred embodiment is described wherein the insertion loss is 3 dB for a design which provides an extinction ratio of 20 dB. The materials of the present invention, when configured as the core of a simple thermooptically controlled waveguide, rather than the more complex configuration of a Y-branch waveguide, a Mach-Zehnder interferometer, or a thermooptically controlled leaky waveguide cladding, would provide an insertion loss of below 0.1 dB/cm and 22 dB of extinction ratio for every centimeter of waveguide length. Thus, the present invention promises a significant reduction in complexity, and a substantial improvement in performance for thermooptically controlled devices over that of the prior art.
A further advantage of the present invention is that it exhibits a high thermooptic control coefficient. That is, for a modest change in the control parameter (temperature), a large change in signal attenuation is realized. The measured thermooptic control coefficient for compositions of the present invention is in the range of 6 dB/cm/° C. When combined with the low insertion loss of the present invention of less than 0.1 dB/cm, this figure of merit implies that for a relatively small change in temperature along a waveguide, a relatively large change in attenuation can be achieved. For example, a ten-centimeter long waveguide attenuator using a composition of the present invention would exhibit an insertion loss of 1 dB and 60 dB/° C. thermooptic coefficient. So, with a control temperature change of only 0.2° C., such a device could switch 10 dB in attenuation. Allowing such a small change in temperature is a significant advantage over the prior art because it permits, for a given thermooptic heating/cooling power per unit length, a more rapid switching speed in any device utilizing compositions of the invention.
Yet another advantage of the present invention is that it enables design of components that have attenuation that is smoothly varying and varies only gradually across its wavelengths of operation. Some thermooptically controlled devices must be optimized for performance in narrow bands of spectrum because their attenuation performance relies on resonance or nulling phenomena. For example, devices which rely on the thermooptic change of refractive index of a polymer waveguide arm of a Mach-Zehnder interferometer must be optimized for a center wavelength. Variation of operating wavelength by more than one quarter of the center wavelength value renders the device unable to achieve its ideal phase cancellation point. In the prior art disclosed in U.S. Pat. No. 6,165,389, a switching medium is described which depends on a volume phase transition phenomenon in the thermooptically active material; a preferred embodiment exhibits variation in optical absorption which is strongly resonant in wavelength. By contrast to the foregoing prior art examples, the present invention relies on bulk absorption due to a "cloud point" phase transition phenomenon; in addition, its absorption characteristics vary only slowly across the entire wavelength band from 300 nm to 2000 nm without any rapidly varying resonance attenuation features. Using compositions of the present invention, devices can be configured which exhibit only small changes in optical absorption across wavelength, which we denote "insertion loss flatness". A preferred embodiment of the invention, for example, achieves a worst case insertion loss flatness of less than 0.01 dB/nm in the vicinity of NIR telecommunication bands over the wavelength range of 1200 nm to 1600 nm.
A further characteristic of some optical polymer media such as liquid crystal polymer media is that they exhibit birefringence, meaning that their index of refraction is significantly different for the two orthogonal signal polarizations. This in turn leads to a deleterious feature known as polarization dependent loss (PDL). In some applications such as polarization independent waveguide switches, or free space neutral density filters, it would be desirable to realize behavior for a switch medium that is non-birefringent in nature and exhibits minimal PDL. The cloud point mechanism which gives the present invention its switching characteristics is intrinsically non-birefringent in nature and may therefore be advantageous in such applications.
The composition of the present invention may be used to fill an optical waveguide structure. Such structures are commonly designed to ensure propagation in a single waveguide mode. There are structures used in the telecommunications field, which are also based on propagation of multiple modes, known as multimode waveguides. The compositions of the present invention may be used to fill both single mode and multimode waveguide devices. The prior art of optical waveguides as described in U.S. Pat. No. 5,692,088, also includes optical waveguides comprising a liquid core. Compositions of the present invention may exist in a liquid, a quasi-liquid or a solid state over a portion of their operating temperature service range. The distinctive feature of the compositions of the present invention is that they exhibit a transition in optical absorption, which may be controlled through variation in temperature. Devices that will benefit from the incorporation of the invented composition into waveguide structures include waveguide switches, programmable waveguide attenuators, and controllable waveguide shutters.
In some applications for the present invention, the electromagnetic wave propagates in an unguided free-space mode rather than in a guided waveguide mode. Projection display optics, high power laser optics, and other optical systems sometimes require neutral density filters, or controllable attenuators, or shutters which control the free-space amplitude of an optical wavefront. In the prior art, reflective/absorptive free-space elements have been fabricated using transparent liquid crystal arrays, or using microelectromechanical switch (MEMS) elements, or using electrically controlled crystal elements such as Pockels cells. In one embodiment of the present invention, a free-space attenuating screen is formed by filling the gap between two closely spaced transparent sheets of glass with the invented composition. The temperature of the composition is varied to permit switching of the state of the filter through a range of neutral density values. This approach may be carried further to allow, across the two-dimensional face of the filter, independent control of localized attenuation. In this way, the present invention could be used to realize controllable beam shavers, image pixel amplitude equalizers, holographic image attenuation controllers, and the like.
The prior art also contains many compositions in the art of manufacture of greases, gels, plastics, paints, and other compounds wherein the mechanical properties of the compositions are altered by the addition of powder thickening agents such as nanopowder silica, oxides, soaps, clays, or other materials. In some embodiments of the present invention, it may be advantageous to increase the viscosity or stiffness of the invented compositions by means of addition of these components. It is preferred in these cases to select thickening agents that do not unduly increase the level of haze in the composition. This may be accomplished, as is well known in the art of transmissive optical polymer compositions, by minimizing the effective particle size of the thickening agent, minimizing the volume fraction of the agent within the composition, and selecting agents with maximal optical clarity and with index of refraction close to that of the base composition. In like manner, fluid thickening agents such as tackifiers, or other high viscosity fluids which are miscible with the base composition and which are well known in the art of lubricant formulation may be compounded into the base composition in order to increase its viscosity and reduce its tendency to migrate or flow once it is dispensed into the optical assembly.
The prior art of compounding of greases, plastics, lubricants, and other compounds also contains knowledge regarding the addition of small percentage quantities of additives or fortifiers, such materials being included in compositions at up to 10% by weight. Additives may be either soluble or insoluble in the base fluid of the composition. Additives serve to imbue the composition with a variety of improvements in properties. An illustrative but incomplete list of types of additives is as follows: anti-oxidants, lubricity additives, surfactants, fluorescent dyes, absorbing dyes, electrical conductivity additives, and metal scavengers or passivators. Many such additives are available for purchase from the additive chemical supplier base. Fortifiers can include insoluble species such as oxide powders, fluorescing powders, nanotubes, nanospheres, microspheres, pigments, liquid crystals, and other materials. It is envisioned that some such additives and fortifiers could be included in compositions of the present invention provided that the key optical performance parameters for the composition such as insertion loss and extinction ratio are not unduly degraded. It is further envisioned that compositions of the present invention could be employed as a bulk medium to physically support arrangements of various fortifier species for the purpose of forming a photonic crystal, a Bragg reflector, a frequency doubling film, or numerous other photonically active materials.
The present invention permits the thermooptic control of signal amplitude in a waveguide or free space propagation configuration with substantial improvements in: ON-state insertion loss per unit length, extinction ratio per unit length, thermooptic control coefficient per unit length, insertion loss flatness, and polarization dependent loss.
The invention relies on the optical characteristics of a "cloud point" phase transition phenomenon. A "cloud point" is the property of a fluid or fluid mixture to change from clear to cloudy as it is cooled and passes through a precipitation transition. The most familiar example of this phenomenon is the transition of paraffin wax from a clear fluid in its melted state to a hazy soft solid in its solid state. In the field of petroleum fluid technology, the cloud point is a temperature at which a mixture of two or more fluids transitions from clear to hazy as one of the species precipitates out of solution as a microcrystalline wax. Since polymers generally comprise mixtures of a number of molecular weight species of related chemical structure, the cloud point transition is often not sharply defined with respect to temperature. However, by controlling the range of molecular weight within narrow limits, the transition can be sharpened, affording more dramatic thermooptic control and higher and more advantageous thermooptic control coefficient. As is known in the art of design of synthetic waxes, it is also possible to vary the nominal molecular weight of a particular type of wax such that its cloud point, and therefore the composition's nominal ON/OFF transition temperature point, can be selected to be most advantageous for a particular application. Molecular weight homogeneity of a polymer fluid or wax may be improved by techniques well known in the art of polymer manufacture such as distillation, wiped-film vacuum fractionation, supercritical fluid extraction, and the like.
It is unproven whether the thermooptic response of the present invented compositions are limited solely by the rate at which the control temperature may be varied within the composition as limited by the heat transfer design of the device employing the composition. However, it is expected that embellishments of the invented composition will serve to sharpen the thermooptic response and enable faster switching speeds. First, the range of the molecular weights of the wax portion of the composition may be controlled within narrow limits as described above. It is speculated but not proven that the addition of a small quantity of inert solid fortifier powder to the composition will provide nucleation sites for condensation of the microcrystalline wax phase of the composition, improving the speed at which the composition can transition from the ON to the OFF state. It is expected but not proven that externally applied pressure changes will also increase the thermooptic coefficient of the composition. It is envisioned that such pressure changes could be applied, for example, by passive means in a device design by arranging for the structure which encloses the invented composition to expand or contract the enclosed volume at a predetermined rate with temperature. This could be accomplished, for example, by choice of enclosing structure materials with coefficients of thermal expansion and/or controlled heating and cooling which achieve the volumetric changes needed to apply the desired static pressures.
In some applications of the present invention, it is advantageous to formulate a composition which is a high viscosity flowable fluid. This allows the material to be more easily poured or dispersed into small spaces in the optical assembly. In the preferred embodiment of the invention, a wax is dissolved in a flowable fluid to make a plasticized mixture which is highly viscous but pourable under pressure. It is opaque at room temperature and clears to be highly transmissive at temperatures above 34° C. It may be desirable that compositions of the present invention remain highly viscous throughout the OFF portion of their service temperature range. This feature serves to immobilize the precipitated wax species and prevent it from separating out as distinct phases through buoyant or agglomerative forces, thereby causing unwanted optical performance effects. On the other hand, it may also be desirable in some applications to ensure that at the extreme lower limit of its service temperature range the material retain sufficient pliability to avoid formation of fractures within the composition or delamination of the composition from surrounding substrates. It is postulated, but as yet untested, that this requirement may be equivalent to requiring that the composition contain a non-freezing fluid component which serves to plasticize the wax at cold temperatures and prevent fractures or delamination. The prefered embodiment of the invention contains such a plasticizing fluid component.
It is also possible to conceive embodiments of the optical devices of the present invention comprising solely a wax which is opaque and immobile or semi-solid at room temperature without flowability, but is flowable above its cloud point.
If the wax and fluid are chosen to be of types that have viscosity which decreases rapidly with increasing temperature, the composition may have additional advantages for manufacturing. By heating such a fluid well beyond its operating temperature, the fluid may be made low in viscosity so that it may be more easily injected into the optical device; upon being cooled to its service temperature range the fluid mixture reverts to its higher viscosity and immobile state. It is a feature of the preferred embodiment of the present invention that it has a high viscosity temperature coefficient in order to obtain this manufacturability advantage.
It is envisioned that in some applications, such as outdoor telecommunications applications where the service temperature environment reaches 85° C. or higher, that the desired cloud point transition would be set to be somewhat higher than this maximum service temperature, for example, at 90° C. This would allow the device designer to perform the thermooptic control by means of a heating element only, without the need for an active cooling element. As an example, a practical control approach would be to design the device package to operate at a continuous internal temperature of 85° C., representing the standby OFF-state. A stepped up heating state would be designed to boost the temperature to a 95° C. to switch the composition to the ON-state. To switch from ON to OFF, the stepped up heating state would be disabled, allowing the device to cool, via passive heat-sinking to ambient temperature and return the composition to the OFF-state. In other applications, where nominal ambient temperature is room temperature, a suitable cloud point transition would be chosen for the composition to be slightly above room temperature. As with the example just cited, one could use a control heater to raise the temperature to the ON-state, and rely on equilibration with ambient temperature to switch the composition to the OFF-state. It is a feature of the invented composition that within classes of appropriate polymer fluids and waxes, that a wide range of cloud point temperatures can be selected to suit a particular application. For example, with the preferred embodiment of the invention, higher and lower melting point waxes could be chosen to mix with the base clear fluid so as to move the cloud point higher or lower in temperature. Such design flexibility would be helpful, for example, if the switch state while unpowered at ambient temperature were specified to be fully OFF (sometimes called "normally open"), or fully ON (sometimes called "normally closed"). One application which would benefit from a "normally open" version of the invented composition would be a waveguide safety shutter for long haul telecommunications fiber carrying eye-damaging levels of infrared laser radiation.
The compositions of the present invention are comprised of at least one material component which has the following properties:    1) at the OFF temperature the material component (the "wax") is an optically opaque semi-solid or solid material (the "wax");    2) at the ON temperature the wax is optically clear.A preferred embodiment of the invented compositions are those which are comprised of at least two miscible but distinct materials which have the following properties:    1) at the OFF temperature one is an optically clear fluid (the "fluid") and one is a wax;    2) at the ON temperature both materials are optically clear and they are miscible in proportions of at least 1:100 (fluid:wax) but more preferably are infinitely miscible;    3) at the OFF temperature the mixture of materials has a viscosity which is sufficiently high to prevent separation of the phases of the two materials; preferably the OFF viscosity of the mixture is at least 1000 cP, and more preferably is at least 20,000 cP.A preferred embodiment of the invented compositions is one which is optically transmissive in the near infrared in the ON state comprising:    1) ten to ninety parts by weight of a fully halogenated, substantially bonded-hydrogen free, chlorotrifluoroethylene polymer fluid;    2) ninety to ten parts by weight of a fully halogenated, substantially bonded-hydrogen free, high molecular weight chlorotrifluoroethylene wax.
Other combinations of materials can be conceived which follow the invented prescription. For example, a thermoplastic composition which exhibits microcrystallinity below its microcrystalline transition temperature will exhibit behavior vs. temperature which mimics compositions of the present invention. In this sense, any material which exhibits a microcrystalline precipitation vs. falling temperature exhibits the properties of the "wax" component of the present invention's compositions, and can be used with optical devices of the present invention provided that such transitions are reversible and repeatable. Examples of such embodiments of the present invention would be optical devices incorporating the following: polytetrafluoroethylene compositions, polyalphaolefin compositions, paraffin wax compositions, hydrocarbon microcrystalline wax compositions, polypropylene compositions, partially or fully halogenated wax compositions, siloxane resins or fluids, polyphenylether or polyphenylthioether resins or fluids, and the like.
For the purposes of the present invention, a thermooptically active or thermooptically controllable composition is a composition which can be controlled to have an opacity which varies over a range of temperature in a well-defined, reversible, and repeatable manner between an "ON-state" which is substantially transparent and an "OFF-state" which is substantially opaque.
Unless otherwise specified, "optically clear" is taken to mean having an optical transmission of greater than 90% over a 1 mm path length at the intended "ON state" temperature and at the intended wavelength of transmission as measured using a grating spectrophotometer with an instantaneous spectral bandwidth of 10 nm or less.
Conversely, "optically opaque" is taken to mean having an optical transmission which is less than 90% at the intended "OFF state" temperature and at the wavelength of intended use.
Unless otherwise specified, "ultraviolet" is taken to mean a range of wavelengths from 100 nm to 400 nm, "visible" is taken to mean a range of wavelengths from 400 nm to 750 nm, and "near infrared" is taken to mean a range of wavelengths from 750 nm to 2000 nm.
Unless otherwise specified, "index of refraction" or "refractive index" is taken to mean the value of refractive index of a medium measured at 25+/−0.5 degrees centigrade and 589 nm, as measured by the method of Abbé refractometry according to ASTM D-1218, or equivalent method. This definition is the convention in the optics industry, even when the intended wavelength of use of the material differs from 589 nm as is the case with wavelengths in the near infrared.
Unless otherwise specified, a statement that two adjacent optical materials are "index-matched" is taken to mean that they differ in refractive index by no more than 0.06. By this definition, a fused silica fiber (refractive index=1.46) is index-matched to a composition of the preferred embodiment of the present invention (refractive index=1.42).
Unless otherwise specified, "service temperature" indicates temperature limits or ranges at which or over which the optical performance criteria are applied. The composition may also be subjected to temperatures above or below its service temperature limits, but without necessarily meeting its optical performance criteria.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.

Compositions and devices for thermooptically controlled switching and filtering


A three-dimensional (“3D”) image display device includes a display panel assembly which displays a two-dimensional (“2D”) image including a left region and a right region, which are divided by an axis, and the display panel assembly repeatedly rotates back and forth by a predetermined angle with respect to the axis.

(a) Field
A three-dimensional ("3D") image display device is provided.
(b) Description of the Related Art
In general, a 3D image display technology realizes a 3D effect of an object using binocular parallax for recognizing a 3D effect at a short distance. That is, when different two-dimensional ("2D") images are reflected in a left eye and a right eye, respectively, and the image reflected in the left eye (hereinafter referred to as a "left eye image") and the image reflected in the right eye (hereinafter referred to as a "right eye image") are transmitted to a brain, the left eye image and the right eye image are fused in the brain to be recognized as a 3D image having depth perception.
A 3D image display device using the binocular parallax is typically classified into a stereoscopic type using glasses such as shutter glasses, polarized glasses or the like, and an autostereoscopic type without using glasses, in which a lenticular lens, a parallax barrier, or the like, is disposed in a display device.


A system and method of the subject technology displays non-geographic information associated with a viewed point of interest in an interactive internet map. When the map is repositioned by a user, a new point of interest is determined based on one or more coordinates and one or more predefined rules, and new non-geographic information is automatically generated and displayed for the new point of interest, all without a user having to enter search criteria.

Some search engines may include, in connection with a search input, an interactive internet map displayed within a computer-enabled interactive viewport (for example, in a region of a web browser). A user may input a point of interest (for example, a geographic location) as a text query to view the point of interest in the internet map, along with non-geographic information related to the viewed point of interest. This manual process may then be repeated to view non-geographic information relevant to other points of interest.

System and method for displaying information local to a selected area


Disclosed are apparatus and method for determining whether a foreign object or the like is caught in an open-and-closure mechanism such as a power window of an automotive vehicle. An external disturbance torque T imposed on a the open-and-closure mechanism motor as its load is calculated on the basis of at least two of three parameters of a terminal voltage Em across the motor, a current flowing through the motor Im, and a motor angular velocity .omega.. Furthermore, the calculated external disturbance torque is differentiated to derive a change rate at which the external disturbance torque T is changed with time as dT/dt (T'). Since dT/dt (T')=dTs'/dt (Ts')+dTd'/dt (Td') and dTd/dt (Td')=0 (Td: a dynamic friction resistance force and dTd/dt: the change rate of the dynamic friction resistance force per time), dT/dt=dTs'/dt (Ts: an external disturbance force imposed on the motor by the caught foreign object and dTs/dt (Ts'): the differentiation value of the external disturbance force). When the change rate (dT/dt or T') of the external disturbance torque T is compared with a predetermined threshold value (Kw in a second embodiment), an accurate determination of whether the foreign object or the like is caught in the open-and-closure mechanism can be made since an aged deterioration and/or a temperature variation in the dynamic friction resistance Td are almost not included in the change rate (dT/dt, T') at which the external disturbance torque T is changed with time.

a) Field of the Invention
The present invention relates to apparatus and method for determining a presence or absence of a foreign object or the like is caught in a power open-and-closure mechanism such as a power window installed on an automotive vehicle, a power sun roof installed on a ceiling of a passenger compartment of the automotive vehicle, a power door closure mechanism, or the like without using a special-purpose sensor such as a torque sensor.
b) Description of the Related Art
A Japanese Patent Application First Publication No. Heisei 6-253570 published on Sep. 9, 1994 exemplifies a previously proposed motor control apparatus for a power open-and-closure mechanism which can determine whether a foreign object or the like is caught in the power open-and-closure mechanism.
In the above-identified Japanese Patent Application First Publication, an external motor disturbance force imposed on a motor as a load and generated due to a foreign object such as a human body or the like being caught in the power open-and-closure mechanism (hereinafter, referred simply to as an external disturbance force) is calculated from a motor drive current and a motor terminal voltage in addition to a motor angular acceleration.
Then, on the basis of the calculated external disturbance force imposed on the motor, the current flowing through the motor is controlled by means of a chopper operation using PWM (Pulse Width Modulation) pulses through a, so-called, H bridge drive circuit constituted by four cross-coupled semiconductor switching devices in such a way that the external disturbance force is reduced when an application of the external disturbance force to the motor driving the power open-and-closure mechanism occurs. Consequently, the foreign object or the like can be prevented from being continued to be caught in the power open-and-closure mechanism at a low cost.

Apparatus and method for determining presence or absence of foreign object or the like caught in power-open-and-closure mechanism


A steering column assembly for a vehicle includes a support bracket and a column jacket coupled to the support bracket. A compression bracket is mounted to the column jacket. A clamping device is disposed on the support bracket and has a rake bolt extending through the support bracket and the compression bracket for applying a frictional force on the support bracket to prevent telescoping and tilting movement of the column jacket and the compression bracket relative to the support bracket. An actuation mechanism is coupled to the support bracket. The actuation mechanism rotates the rake bolt in a first direction to prevent telescoping and tilting movement of the column jacket. Likewise, the actuation mechanism rotates the rake bolt in a second direction to permit telescoping movement of the column jacket and the compression bracket relative to the actuation mechanism and the support bracket and tilting movement.

1. Field of the Invention
The present invention generally relates to a steering column assembly having an actuation mechanism for telescoping and tilting movement.
2. Description of the Related Art
Various steering column assemblies in vehicles are known in the art. Many vehicles are now equipped with steering column assemblies that allow for telescoping movement to adjust a distance between a driver of the vehicle and a steering wheel supported by the steering column assembly and tilting movement to adjust an angle of the steering column assembly relative to the driver. Despite these telescoping and tilting features, it is preferred that the steering column assembly remains stationary except when telescoping or tilting movement is desired by the driver. To prevent telescoping and tilting movement of the steering column assembly, various steering column assemblies use a compression bracket mounted to a column jacket.
An example of such a steering column assembly is shown in U.S. Pat. No. 7,093,855 (the '855 patent). The '855 patent discloses a steering column assembly for a vehicle that includes a support bracket for attachment to the vehicle. A column jacket is coupled to the support bracket and extends along a longitudinal axis. A compression bracket is mounted to the column jacket and defines a telescoping slot parallel to the longitudinal axis. A clamping device is disposed on the support bracket. The clamping device has a rake bolt extending transverse to the longitudinal axis, and the rake bolt extends through the support bracket and the telescoping slot of the compression bracket. With the rake bolt, the clamping device is able to apply a clamping force on the support bracket transverse to the longitudinal axis. When the clamping device applies the force, friction between the compression bracket and the support bracket prevents telescoping movement of the column jacket. To actuate the clamping device, the '855 patent discloses a lever connected to the clamping device.
The lever of the '855 patent is disposed off to the side of the column jacket. However, due to size constraints, it can be beneficial to provide a steering column assembly with the actuator centrally located with respect to the column assembly.

Steering column assembly having an actuation mechanism for telescoping and tilting movement


The invention relates to the novel use of a pharmaceutical product which combines domperidone and pseudoephedrine sulphate substances and which can be used to reduce or stop moderate or severe snoring.

The present invention is applied in the field of medicine, more specifically to treat snoring.
Interest in sleep apnea has increased in recent years due to studies that have been carried out that show that it is a very common condition, which, if left untreated, can be linked to serious cardiovascular illnesses. Access to more trustworthy diagnostic methods and effective treatment help to advance the research and evaluation of diagnosis and therapy by different specialists.
At the moment there are a number of homeopathic remedies which use natural plants and herbs that fluidify the mucous secretions of the palate, to aid the flow of air. Also, there are several 'sprays', nasal drops and local or general aromatherapy, nasal lubricants and external correctors to dilate the nostrils. In the United States, more than 50 devices have been patented, to be used locally such as sosmnoguard amongst others and there are special inflatable pillows to prevent people sleeping on their back, ribbons or collars that close the mouth by raising the jaw.
(Stamped)
An Internet search detected 158,080 sites that provide information about treatment for snorers, in which you can see a whole range of treatments from hypnosis to surgery.
There are various invasive treatments, but the most common are the following:
1. Snoreplasty by injection that infiltrates alcohol or sodium tetradecyl sulphate in the palate to harden it. Its effects take weeks to appear and according to its authors, the resulting sclerosis is beneficial.
2. Uvulopalatoplasty by laser, which is very fashionable at the moment, even in our country. Said technique involves the surgical ablation by laser of the soft palate and the uvula to create a wider airway. Apart from its aggressiveness, its results are questionable as reported in a separate study by ENT specialists (Arch. Otolaryngol. Head Neck Surg., 2001, 127, 412-417); that shows a 43% initial satisfaction rate with the procedure which decreases in later check ups. In said publication, the authors note that it can produce fibrosis and adherence of the residual palate, further decreasing the airway making the sleep apnea appear in a large number of patients that previously did not have it.
The latest study published was aimed at nighttime nasal congestion that would be an important independent factor in the habitual snoring without true apnea.
The authors carried out polysomnography on 4,916 patients in Wisconsin (United States), and concluded that the patients with chronic severe nasal congestion were more likely to be habitual snorers (Arch. Intern, Med., 2001, 161, 1514-1519.
Finally, the use of CPAP ought to be mentioned which is a pressurised oxygen infuser system machine for patients with sleep apnea and who need to use it all through the night. Its commercial value is 1,000,000 Chilean pesos for each case and our Health System is not able to provide it as happens in other countries.
The use of efficient surgery in cases of gastroesophageal reflux, by this author at the beginning of the 1970s, led to multiple consequences that were not related before. The patients reported that the day after the operation they could breathe better, asthmatics stopped having attacks and the obstructive bronchitis disappeared in many unweaned babies. This motivated the author to carry out a 15 year study, which was the first study carried out with rigorous testing and method and which has been internationally recognised. During 1974, a relationship between an alteration in the larynx and the gastroesophageal reflux became apparent, which is now known as "acid laryngitis". This alteration causes congestion of the respiratory mucous, where the main symptom is the presence of "hoarseness". Also, it is important to note that in the majority of cases, this lesion does not have symptoms of oesophageal reflux or they are very mild. Its incidence in the normal population is high. It was the concomitance of the disappearance of snoring in the operated cases, reported by family members, which motivated the author to look for a medical treatment to alter the respiratory pathway that exists in snorers that do not have an obvious obstructive anatomical alteration (adenoids, noticeable deviation of nasal septum, etc). The association of the larynx lesion with congestion, steered towards the possibility of using a decongestant along with a substance that increases the gastric and oesophageal motility, which protects acid reflux. Nevertheless, substances that reduce or eliminate the acid secretion cannot be added, because they obstruct the absorption of the aforementioned drug and also the vast majority of patients do not report problems from the presence of gastric reflux content.
This is how PVA103 came about, which is comprised of pseudoephedrine sulphate (60 mg) and domperidone (10 mg) per capsule. Both drugs have been extensively studied (pseudoephedrine appears on 71,000 internet sites and domperidone appears on 9,080 internet sites). In Chile, pseudoephedrine was included in drugs that do not need medical prescription from 1 May 2000. The Director of the Institute of Public Health (ISP) Sr. Gonzalo Navarrete, said at the time "it does not make sense to restrict it, because it is not a dangerous substance". Also, the current Director of the ISP Sra. Jeannette Vega, stated on 17 Aug. 2002 that "drugs that do not require medical prescription do not carry the risk of improper use, abuse or addiction", the side effects that occasionally appear are not severe and are reversible after stopping the medication, these medicines are safe and effective for the population to consume."
As a mid-range, there is the option of using a combination of pseudoephedrine sulphate (60 mg) and pseudoephedrine hydrochloride (120 mg).
The combination of the pseudoephedrine substances with domperidone is new and has not been presented in any country in the world and especially not for its use in snorers. 25% of the population can be classed as severe or moderate habitual snorers. It is a disturbance that can cause problems for co-inhabitants and the possibility of eliminating this problem with a simple medication is very important.
In Chile pseudoephedrine forms part of several preparations, it has been combined with ascorbic acid in 4 preparations, with bromophenylamine in 1 preparation, with caffeine in 2 preparations, with cetirizine in 2 preparations, with chlorphenamine in 45 preparations, with codeine in 15 preparations, with eucalyptus in 1 preparation, with loratadine in 10 preparations, with noscapine in 3 preparations, with paracetamol in 31 preparations, with propyphenazon in 1 preparation, with retinal in 1 preparation, with tolu in 1 preparation and with triprolidine in 2 preparations.
The PVA103 preparation has been administered to volunteers in the form of a capsule 30 minutes after the evening meal in which a moderate consumption of alcohol is permitted or two glasses of wine. If after 4 hours the volunteer starts to snore again, he/she can take another dose. In the trials no problems were noted and the result, the disappearance of snoring, is notable.
Apart from the obvious benefits for the patient this preparation is low cost with the consequent large-scale use and benefit, it constitutes a new use of two known compounds, which if administered in the dose indicated above, constitutes a new compound that resolves the technical problem that does not have equivalent solution.

Pharmaceutical product which is used to reduced or stop moderate or severe snoring


A current source and/or current sink digital-to-analog converter (DAC) includes a DAC circuit that converts a digital code to an analog current or voltage signal, an optional transconductance circuit that converts a voltage output of the DAC circuit into a current signal, and an output circuit that amplifies a current output of the DAC circuit or optionally amplifies a current output of the transconductance circuit to set a desired high current output for application to an output of the current source and/or current sink DAC. A power supply control current may be coupled to a power supply circuit that supplies power to the output circuit of the current source and/or current sink DAC. The power supply control current adjusts the output of the power supply circuit to cause the current source and/or current sink DAC to operate at a higher power efficiency.

Programmable current source or current sink digital-to-analog converters (DACs) operate by converting a precision DAC voltage or current into a high output current via an output circuit. The high output current can be 300 mA or greater.
Such current source/sink DACs have uses in optical communication systems for optical component biasing. Most of these current source/sink DACs have separate power supply pins for the precision DAC core (VDDDAC) and an output circuit (VDDX/VSSX) that enables higher power efficiency. In general, most of the total power is dissipated in the output circuit. A solution to reducing power dissipation is to lower the power supply voltage of the output circuit. In the case of a current source DAC, by setting the power supply voltage of the output circuit lower than the precision DAC core power supply (VDDX<VDDDAC), significant power savings can be achieved. However, VDDX voltage cannot be lowered arbitrarily as there exists a minimum VDDX voltage, VDDX(MIN), below which the output circuit cannot function properly. For this reason VDDX can be set to be higher than or equal to VDDX(MIN). Another constraint on VDDX voltage is due to the minimum dropout voltage requirements of the output circuit. Dropout voltage, VDROPOUT. is equal to (VDDX−VOUTX), where VOUTX is the voltage at the output pin of the current source DAC. Lowering VDROPOUT also improves power efficiency since the output circuit power is equal to VDROPOUT+IOUT, where IOUT is the high output current of the current source DAC. However, similar to VDDX, VDROPOUT cannot be arbitrarily lowered either, since the current source DAC requires VDROPOUT to be greater than a minimum value, VDROPOUT(MIN), to be functional. Given these two constraints, lower power dissipation and higher power efficiency can be achieved when VDDX is set to the higher of the two voltages, VDDX(MIN) and VOUTX+VDROPOUT(MIN), or equivalently VDDX=max{VDDX(MIN), VOUTX+VDROPOUT(MIN)}.
A typical application for a current source DAC is semiconductor optical amplifier (SOA) biasing. SOAs amplify light without converting it to electricity. For optimum performance, very accurate biasing (up to 16 bits of DAC resolution) is desired. Also, it is desirable to place SOAs in physically small optical modules, so reducing power dissipation is also desired. Accordingly, in scenarios where a current source DAC is used to bias a SOA, the output voltage VOUTX would be equal to VSOA, where VSOA is the SOA forward voltage. In general, VSOA>VDDX(MIN), so for higher power efficiency, VDDX can be set to VOUTX+VDROPOUT(MIN) or equivalently to VSOA+VDROPOUT(MIN) to reduce total power dissipation. VSOA and VDROPOUT(MIN) are not constant voltages and can dynamically vary due to changes in programmed DAC output current, process variations, change in voltage levels or temperature, or over time. However, VDDX voltage is generally set as a constant voltage and is not dynamically adjusted. Hence, worst case values for VSOA and VDROPOUT(MIN) are usually used to set VDDX to make sure the current source DAC remains functional as VSOA and VDROPOUT(MIN) vary.
The worst case values for VSOA and VDROPOUT(MIN) vary significantly compared to their nominal values, over programmed DAC output current, process variations, voltage, temperature, and over time, thus causing excess power dissipation by the current source DAC during nominal conditions. It is therefore desirable to be able to dynamically adjust VDDX voltage in the presence of aforementioned VSOA and VDROPOUT(MIN) variations, such that the power dissipation by the current source DAC is reduced compared to the case where VDDX voltage is set as a constant voltage and no dynamic adjustment is made.

Analog Devices International Unlimited Company