OBDD variable ordering by interleaving compacted clusters

An effective method for variable ordering of OBDDs (ordered binary decision diagrams) based on the interleaving of the compacted clusters is proposed. The novelty of this method lies in the application of the divide-and-conquer approach to efficiently find a good variable ordering for circuits with a large number of I/Os. One notable result from this method is that the OBDD is able to be built using the cs38417 circuit, the remaining unreported circuit in the ISCAS89 benchmark     

ROBDD complexity analysis for XOR/XNOR min-terms

This paper discusses the complexity of reduced ordered binary decision diagrams (ROBDDs) for Boolean functions with XOR/XNOR min-terms. Knowing the number of variables and the number of product terms of Boolean function containing only XOR/XNOR min-terms, one can predict the number of nodes in its ROBDD representation without building the binary decision diagram (BDD). A mathematical model for this prediction has been developed. This model can be used to find the maximum number of nodes for a given number of variables. Theoretical and experimental results are reported to underline the efficiency of this approach. The experimental results show that even though the XOR/XNOR min-terms cannot be simplified using Boolean laws or any other simplification method leading to a better min-term representation, the ROBDD will perform the simplification using the ROBDD reduction rules. The required memory is analysed for different methods of representation, and this analysis showed that ROBDDs are memory efficient structures to store and represent large numbers of XOR/XNOR min-terms in Boolean functions.     

Current-mode circuits for the unary functions of a ternary variable

The unary functions of a ternary variable other than those of constant value are classified into three basic types. Current-mode circuits are given for the realisation of each function type. The circuits have high speed and large fan-out capabilities and are especially suited to fabrication by i.c. methods.     

Partitioning of Boolean functions by variable complementation

A method is presented which enables any Boolean function(s), defined on n variables, to be partitioned. Each partition so extracted is independent of a selected number of the defining variables, and hence each member of such a partition may be defined on the remaining variables. The method is applicable to logic-network synthesis, and its exhaustive application enables a fast implementation of the Quine-McCluskey1?3 minimisation algorithm.     

Enhanced detection with new ordering schemes for V-BLAST systems

This letter proposes a new optimal ordering method which minimizes error propagation in the vertical Bell-lab Layered Space-Time (V-BLAST) by exploiting the whole filter output. A suboptimal ordering metric is also proposed which requires much reduced complexity compared to the optimal ordering metric. We also derive a simplified version of the suboptimal ordering metric which achieves a significant performance gain over the conventional ordering with minor additional complexity.     

A simple ordering policy with linear lifetime for a unit

In this paper optimum ordering policies of a one-unit system where each failed unit is scrapped and each space is only provided after a lead time by an order with a deterministic linear lifetime for the unit is considered. The optimum ordering policy minimizing the expected cost per unit time in the steady state is discussed by introducing the two types of constant lead times along with ordering costs and downtime cost. The problem concludes with a numerical example minimizing the expected cost function.     

Optimum ordering policies for an equipment with a sensing device

This paper conerns the optimum ordering policy for a single equipment with a sensing device attached, where operational conditions of the equipment are monitored by the attached sensing device continuously. Both the equipment and the sensing device are subject to random failures. It is shown that there exists under certain conditions a finite and unique optimum ordering policy maximizing the cost effectiveness which is used as a criterion for optimality. Numerical examples are presented for illustration.     

Optimum ordering policies with random lead times

This paper studies an optimum ordering policy for a single unit system with general life times and two kinds of orders (regular and emergency) with generally distributed lead times. The costs considered include salvage and observation costs along with shortage and reordering costs and an expression for cost effectiveness defined as (s-availability)/(s-expected cost rate), which balances the system effectiveness and the cost is derived. Two theorems regarding the existence of a finite and unique reordering time for regular orders maximizing the cost effectiveness are proved. For purpose of illustration numerical results are also obtained.     

A transformation for ordering multispectral data in terms of imagequality with implications for noise removal

A transformation known as the maximum noise fraction (MNF) transformation, which always produces new components ordered by image quality, is presented. It can be shown that this transformation is equivalent to principal components transformations when the noise variance is the same in all bands and that it reduces to a multiple linear regression when noise is in one band only. Noise can be effectively removed from multispectral data by transforming to the MNF space, smoothing or rejecting the most noisy components, and then retransforming to the original space. In this way, more intense smoothing can be applied to the MNF components with high noise and low signal content than could be applied to each band of the original data. The MNF transformation requires knowledge of both the signal and noise covariance matrices. Except when the noise is in one band only, the noise covariance matrix needs to be estimated. One procedure for doing this is discussed and examples of cleaned images are presented     

Distributed channel allocation for PCN with variable rate traffic

We consider the design of efficient channel allocation algorithms in personal communication networks (PCN) where the cells have varying traffic loads. A common communication channel is to be dynamically shared between the cells. We propose a distributed intercell channel allocation policy that is easy to implement through the use of simple signaling between neighboring cells. For cells arranged in a line, we show that the proposed policy achieves maximum throughput. The same is true when the cells are arranged in a circle and the frequency reuse distance is 2, while for larger reuse distances and planar hexagonal arrays, the policy may not always achieve maximal throughput. For general circular arrays, we enhance the policy to achieve maximal throughput asymptotically as the number of cells increases. For planar hexagonal arrays, we show that the policy can guarantee throughputs which are fairly close to maximal     

Microstrip stepped impedance filters with variable dielectric or variable width

A stepped impedance filter has been realised on a modified substrate. The change in impedance was achieved by varying the dielectric constant in the substrate while maintaining a constant width of the microstrip. In contrast to conventional stepped impedance filters the impedance is varied by the dielectric constant instead of the microstrip line width. The manufactured filter was measured and compared with an equivalent conventional stepped impedance filter. It is shown that the modified substrate technology could offer an alternative to the standard approach for the stepped impedance filter. In combination with new materials with a high permittivity the technology could also offer a denser package since the microstrip width could be controlled as desired.     

串并联谐振变换器是电除尘器电源的最佳选择

文章从电除尘器机理和粉尘的比电阻的分析与节能减排的要求出发,指出高频高压直流开关电源和直流脉冲电源是ESP电源发展的两个方向。并进一步分析和比较了各种谐振变换器的特点,从而论证了串并联谐振变换器（SPRC）是电除尘器（ESP）电源的最佳选择。     

管道的力量

数字机顶盒作为数字电视传播过程一个过渡性产品,已经逐渐进入人们生活,本文试图分析数字电视机顶盒产品的未来发展趋势,并探讨其与其他家庭娱乐设备的兼容和互相博弈的过程,进而给出机顶盒产品的未来发展方向。     

Predictive ordering and linear approximation for image datacompression

A method of efficient image coding called predictive ordering and linear approximation (POLA) is presented. By taking as reference the previously-received scan line, the pixels of the present scan line are placed in order of decreasing amplitudes. The regression line of the ordered pixels is estimated. The linear approximation is refined by computing the one-bit error pattern and by preserving the first two sample moments of the scan line. Simulation results are given showing good image quality at a low bit rate of about 1 bit/pixel     

On ordering color maps for lossless predictive coding

Linear predictive techniques perform poorly when used with color-mapped images where pixel values represent indices that point to color values in a look-up table. Reordering the color table, however, can lead to a lower entropy of prediction errors. In this paper, we investigate the problem of ordering the color table such that the absolute sum of prediction errors is minimized. The problem turns out to be intractable, even for the simple case of one-dimensional (1-D) prediction schemes. We give two heuristic solutions for the problem and use them for ordering the color table prior to encoding the image by lossless predictive techniques. We demonstrate that significant improvements in actual bit rates can be achieved over dictionary-based coding schemes that are commonly employed for color-mapped images.     

为信息网络配置具有最佳性价此的UPS供电系统

电源对信息网络的重要性 在当今的社会和经济生活中，对由信息网络所处理的种种信息资源的准确度和时效性的要求是如此之高，哪怕是仅几批数据的错误传送或仅几秒钟的网络瘫痪事故的发生，均会给企业及其用户的正常经营和业务活动带来不应有的损失。从某种意义上讲，信息就是办事效率、财富、金钱。近年来，     

制作变间距光栅的新方法

本文提出一种制作空间频率线性变化光栅的新方法,通过调节该装置的几何结构参数,就可以方便地改变光栅空间频率的变化幅度。给出了光栅空间频率的解析表达式。