Continuous phase quadrature phase shift keyed signaling techniquewith coding

A continuous phase quadrature phase shift keyed (CPQPSK) modulation technique is presented. This method utilizes a conventional QPSK modulator and a phase trajectory converter to approximate M=4, h=1/4 continuous phase signal and allows low cost, low complexity, and high rate (>1 Gbit/s) CPM modem implementation for bandwidth efficient transmission through nonlinear satellite channels. Using a communications analysis computer program it has been found that CPQPSK has 99 percent out-of-band power of 0.8R (MSK has 99 percent out-of-band power of 1.2 R where R is defined as bit rate), continuous phase trajectories, and nearly constant envelope amplitude. Simulation of realistic hardware designs indicate that the CPQPSK will require an Eb/No of 14 dB to achieve a bit error rate (BER) of 10^-6. Forward error correcting techniques using block codes with an overhead of 10 percent indicate that the Eb/No requirements can be reduced to 11.2 dB for 10^-6 BER     

SWEC speeds VLSI simulation

A new simulator called SWEC (StepWise Equivalent Conductance) can efficiently simulate circuits with MOS transistors and passive elements. SWEC adopts four novel techniques: 1) stepwise equivalent conductance implicit integration, 2) piecewise-linear waveform event-driven simulation, 3) recursive convolution formulation based on the Pade approximation, and 4) interconnect partition, to achieve significant speed-ups over existing simulators. The first two timing simulation techniques are briefly reviewed in this article     

A simple HPLC method for the quantification of mizoribine in human serum: pharmacokinetic applications

A simple high-performance liquid chromatographic (HPLC) method was developed and validated for the quantification of mizoribine in human serum. After the addition of 70% perchloric acid and 3-methylxanthine (50 microg/mL, internal standard) to human serum, the samples were mixed and centrifuged at 12,000 rpm (1432 g) for 10 min. The supernatant was injected onto a C(18) column eluted with a mobile phase of 20 mm Na2HPO4 and methanol (93:7, v/v, pH 3) containing 0.04% octanesulfonic acid and detected utilizing an ultraviolet detector at 275 nm. The linear calibration curve was obtained in the concentration range of 0.1-4.0 microg/mL and the lower limit of quantification was 0.1 microg/mL. This method was validated with selectivity, linearity, precision and accuracy. In addition, the method was successfully applied to estimate the pharmacokinetic parameters of mizoribine in Korean subjects following an oral administration of 100 mg mizoribine (two Bredinine 50 mg tablets). The maximum serum concentration (C(max)) of 2.30 +/- 0.83 microg/mL was reached 2.27 +/- 0.66 h after an oral dose. The mean AUC(0-12 h) and the elimination half-life (t(1/2)) were 13.2 +/- 4.79 microg h/mL and 3.10 +/- 0.74 h, respectively.     

Recent advances in VLSI layout

The current status of VLSI layout and directions for future research are addressed, with emphasis on the authors' own work. Necessary terminology and definitions and, whenever possible, a precise formulation of the problems are provided. Placement and floorplanning for both the sea-of-gates and building-block designs are examined. The former emphasizes the connectivity specification, whereas the latter must also consider module shape and size. Global routing based on a method of successive cuts on a chip is discussed. This is a hierarchical top-down approach that is useful for both of the above designs. A two-dimensional detailed routing problem and the rip-up and rerouting problem are also discussed. The field of computational geometry and its application to layout-in particular, to gridless routing and compaction-are reviewed, and layout engines are considered     

Comparison of tracking algorithms for single layer thresholdnetworks in the presence of random drift

This paper analyzes the behavior of a variety of tracking algorithms for single-layer threshold networks in the presence of random drift. We use a system identification model to model a target network where weights slowly change and a tracking network. Tracking algorithms are divided into conservative and nonconservative algorithms. For a random drift rate of γ, we find upper bounds for the generalization error of conservative algorithms that are 𝒪(γ ^2/3) and for nonconservative algorithms that are 𝒪(γ). Bounds are found for the perceptron tracker and the least mean square (LMS) tracker. Simulations show the validity of these bounds and show that the bounds are tight when γ is small and the number of inputs n is large. These results show that the perceptron tracker and the LMS tracker can work well in slowly changing nonstationary environments     

Moment models of general transmission lines with application tointerconnect analysis and optimization

In this paper, we present new moment models for uniform, nonuniform and coupled transmission lines. The moment model of a line is based on the relationships between the two port currents (KCL) and the two port voltages (KVL) of the line. The parameters of the model depend on the mean values of the voltage moments and the weighted voltage moments of the line. Simple formulas are given to compute these mean values efficiently. By using such models and moment matching techniques, interconnects modeled as transmission line networks can be efficiently simulated. In addition, by using moment sensitivities, we demonstrate that wire sizing optimization can be carried out for layout design     

A combined self-organizing feature map and multilayer perceptronfor isolated word recognition

A neural network system which combines a self-organizing feature map and multilayer perception for the problem of isolated word speech recognition is presented. A new method combining self-organization learning and K-means clustering is used for the training of the feature map, and an efficient adaptive nearby-search coding method based on the `locality' of the self-organization is designed. The coding method is shown to save about 50% computation without degradation in recognition rate compared to full-search coding. Various experiments for different choices of parameters in the system were conducted on the TI 20 word database with best recognition rates as high as 99.5% for both speaker-dependent and multispeaker-dependent tests