Block-based motion field segmentation for video coding

In the past few years, motion compensation has been widely used in the coding of image sequences. Most of motion estimation and compensation schemes belong to block-based framework. The framework simplifies the complexity of motion estimation, but gives over constraints to the motion field, which results in worse accuracy on the boundary of moving objects. This paper presents a novel technique for raising motion field accuracy. It uses several pre-defined pattern types to segment the motion fields of the previous frame of a sequence. The segmentation is based on the MAP framework that uses iterative method to obtain the solution. In addition, we develop a predictive scheme to predict the location of motion field discontinuities in the current frame, which further reduces the side information for the representation of segmentation.     

A compact LTCC branch-line coupler UsingModified-T equivalent-circuit modelfor transmission line

In this letter, a compact branch-line coupler is proposed by making good use of the three-dimensional layout capability of the low-temperature co-fired ceramic (LTCC) substrate. This branch-line coupler is accomplished by using lumped-inductors and lumped-capacitors to realize the modified-T equivalent-circuit model for the transmission line so that the circuit size may drastically be reduced. Specifically, a very compact LTCC branch-line coupler with a size of 0.079/spl lambda//spl times/0.0717/spl lambda/ is implemented and carefully examined, where /spl lambda/ is the wavelength of the multilayer structure at the operating frequency f/sub 0/.     

An automatic coefficient design methodology for high-order bandpass sigma-delta modulator with single-stage structure

An automatic coefficient design method for synthesis of bandpass sigma-delta modulators (BPSDMs) is presented in this brief. Single-stage BPSDM structures, cascade-of-resonator with distributed feedback, cascade-of-resonator with distributed feedforward, and a new structure with lower coefficient spread, are all used to fit the synthesized coefficients. The automatic coefficient design method is realized in an easy-to-use computer program. Even for inexperienced designers, reliable and high-tolerance BPSDM coefficients for various applications can be automatically and efficiently generated. The methodology covers many design concerns including BPSDM coefficient tolerance for circuit component mismatch, design tradeoffs among in-band noise suppression, oversampling ratio, modulator order and quantizer bit number. Finally, design examples with orders of 6 and 8, and quantizer bit number of 1-bit and 3-bit, respectively, are used for the verification of the proposed automatic coefficient design method.     

Performance evaluation of LIBTA/hybrid time‐slot selection algorithm for cellular systems

This paper studies the performance of radio assignment algorithms for portable access in cellular systems. Several channel access procedures are proposed and simulated using block oriented network simulator (BONeS) simulation of a model 36‐port system. Simulation results exhibit that load‐sharing system with LIBTA algorithm is better than directed retry system with the same algorithm by around 0.9 erlangs while better than quasi‐fixed channel assignment (QFCA) system by around 2 erlangs if the grade of service (GOS) is constrained to less than 10 per cent. Plus, a hybrid time‐slot selection procedure is proposed to enhance the system performance. It is observed that systems with hybrid time‐slot selection perform better than those with LIBTA algorithm in GOS under heavy load. It is also observed that load sharing system with hybrid time‐slot selection algorithm is better than directed retry system with the same algorithm by around 0.7 erlangs and better than QFCA system by around 2 erlangs. Copyright © 2001 John Wiley & Sons, Ltd.     

RIE gate-recessed(Al0.3Ga0.7)0.5In0.5P/InGaAsdouble doped-channel FETs using CHF3+BCl3 mixingplasma

BCl₃+CHF₃ gas mixtures for the reactive ion etching process were applied to the gate-recess for fabricating (Al_0.3Ga_0.7)_0.5In_0.5P quaternary heterostructure double doped-channel FET's (D-DCFET), where a high uniformity of Vth was achieved. With the merits of this wide bandgap (Al_0.3Ga_0.7)_0.5In_0.5P layer, microwave power performance of this heterostructure D-DCFET demonstrates a compatible performance for devices fabricated on AlGaAs/InGaAs heterostructures     

Accurate quasi-TEM spectral domain analysis of single and multiplecoupled microstrip lines of arbitrary metallization thickness

The quasi-TEM spectral domain approach (SDA) is extended to rigorously and efficiently analyze single and multiple coupled microstrip lines of arbitrary metallization thickness. The charge distributions on both the horizontal and vertical conductor surfaces are modeled by global basis functions. This results in a relatively small matrix for accurate determination of the line parameters of coupled thick microstrips. A convergence study is performed for the results of a pair of coupled lines with crucial structural parameters to explore the conditions for obtaining reliable solutions using the technique. Results for thick microstrips are validated through comparison with those from available measurements and another theoretical technique. The soundness of the technique is further demonstrated by looking into the trend of the results obtained by a simplified model in which the structural parameters are pushed, step by step, to the numerical extremities. Variations of circuit parameters of a four-line coupled microstrip structure due to the change of finite metallization thickness are presented and discussed     

OBDD-based network reliability calculation

An efficient method for evaluating the terminal-pair reliability based on an edge expansion tree and using an OBDD (ordered binary decision diagram) is presented. The effectiveness of the algorithm is demonstrated on the larger benchmarks collected in previous work. One notable case of the experimental results for a 2×20 lattice network is that the number of nodes in the OBDD is linearly proportional to the number of stages. This is significantly superior to previous algorithms which are based on the sum of disjoint products and has exponential complexity     

Optimization of the host/vector system and culture conditions for production of penicillin acylase in Escherichia coli

Culture performance for the production of penicillin acylase (PAC) in a bioreactor was investigated using HB101 or ATCC11105 as the host and pCLL2902, pCLL3201 or pTrcKnPAC2902 as the expression plasmid. We observed that the production of PAC by HB101 harboring pCLL3201 was, similar to ATCC11105, induced by phenyl acetic acid (PAA) and catabolicaily repressed by glucose, whereas the production of PAC by HB101 harboring pCLL2902 did not require PAA for induction and was not repressed by glucose. PAC activity of HB101 harboring pCLL2902 was significantly higher than that of HB101 harboring pCLL3201. There was no significant effect of host or carbon source on the production of PAC using pCLL2902. The production of PAC by HB101 harboring pTrcKnPAC2902, in which the pac gene expression was controlled by the trc promoter system, was about the same as that by HB101 harboring pCLL2902, when the culture was appropriately induced with isopropyl beta-d-thiogalactopyranoside (IPTG). Therefore, the use of both pCLL2902 and pTrcKnPAC2902 could be expected to be feasible for industrial applications. However, optimization of IPTG induction for HB101 harboring pTrcKnPAC2902 might be required, since formation of inclusion bodies tends to limit the production of PAC in some cases.     

基于模糊综合评判的装备维修保障系统效能评估

针对装备维修保障系统效能指标的相对性、模糊性,运用模糊综合评判方法进行系统效能评估。根据完成装备维修保障任务所应具备的能力,建立装备维修保障系统效能评估指标体系,对单项指标采用专家评判法,采用递推算法给出目标层对评语的隶属度,按最大隶属度原则给出优劣等级评定,并由实例得出合理结果。该评估方法思路清晰、计算方便,为装备维修保障系统评估体系标准化提供了一种思路。