The common randomness capacity of a pair of independent discretememoryless channels

We study the following problem: two agents Alice and Bob are connected to each other by independent discrete memoryless channels. They wish to generate common randomness, i.e. agree on a common random variable, by communicating interactively over the two channels. Assuming that Alice and Bob are allowed access to independent external random sources at rates (in bits per step of communication) of H_A and H_B, respectively, we show that they can generate common randomness at a rate of max{min[H_A+H(W|Q),I(P;V)]+min[H_B +H(V|P), I(Q;W)]} bits per step, by exploiting the noise on the two channels. Here, V is the channel from Alice to Bob, and W is the channel from Bob to Alice. The maximum is over all probability distributions P and Q on the input alphabets of V and W, respectively. We also prove a strong converse which establishes the above rate as the highest attainable in this situation     

Counting the number of minimum cuts in undirected multigraphs

The problem of counting the number of cuts with the minimum cardinality in an undirected multigraph arises in various applications, such as testing the super-λ-ness of a graph, as described by F.T. Boesch (1986), and calculating upper and lower bounds on the probabilistic connectedness of a stochastic graph G in which edges are subject to failure. It is shown that the number |C( G)| of cuts with the minimum cardinality λ(G) in a multiple graph G=(V,E) can be computed in O(|E|+λ(G)|V|² +λ(G)|C(G)||V|) time     

On the Distortion SNR Exponent of Some Layered Transmission Schemes

We consider the problem of joint source-channel coding for transmitting K samples of a complex Gaussian source overT bK uses of a block-fading multiple-input multiple-output (MIMO) channel with M transmit and N receive antennas. We consider the case when we are allowed to code over L blocks. The channel gain is assumed to be constant over a block and channel gains for different blocks are assumed to be independent. The performance measure of interest is the rate of decay of the expected mean-squared error with the signal-to-noise ratio (SNR), called the distortion SNR exponent. We first show that using a broadcast strategy similar to that of Gunduz and Erkip, but with a different power and rate allocation policy, the optimal distortion SNR exponent can be achieved for 0 les b les (|N - M| + 1)/ min(M,N) and for b > MNL₂. This is the first time the optimal exponent is characterized for 1/min(M, N) < b < (|N - M| + 1)/min(M, N). Then, we propose a digital layered transmission scheme that uses both time layering and superposition. The new scheme is at least as good as currently known schemes for the entire range of bandwidth expansion factors b, whereas at least for some M, N, and b, it is strictly better than the currently known schemes.     

Implementation of high peak-current IGBT gate drive circuits inVLSI compatible BiCMOS technology

A BiCMOS integrated gate-drive (IGD) application specific integrated circuit (ASIC) has been implemented in a 18 V, 3 μm BiCMOS technology for insulated gate bipolar transistor- (IGBT-) based intelligent power modules (IPM). It features various monitoring and control functions such as linear dV/dt feedback and master-slave control of IGBT's, and is capable of delivering 16-18 A peak current to high capacitive loads. Classic formulas on the current capability of bipolar junction transistors (BJT's), MOSFET's, and metal conductors are briefly reviewed and additional experiments are presented in the context of our application     

超边分解集的递推公式

本文引入了超边的无向分解和有向分解的概念,导出了m点超边的无向分解集SD(m)和有向分解集SPD(m)的递推公式,进而得到它们的基数|SD(m)|和|SPD(m)|的递推公式。     

The L(2,1)-labeling and operations of graphs

Motivated by a variation of the channel assignment problem, a graph labeling analogous to the graph vertex coloring has been presented and is called an L(2,1)-labeling. More precisely, an L(2,1)-labeling of a graph G is a function f from the vertex set V(G) to the set of all nonnegative integers such that |f(x)-f(y)| /spl ges/ 2 if d(x,y)=1 and |f(x)-f(y)| /spl ges/ 1 if d(x,y) = 2. The L(2,1)-labeling number /spl lambda/(G) of G is the smallest number k such that G has an L(2,1)-labeling with max{f(v):v/spl isin/V(G)}=k. A conjecture states that /spl lambda/(G) /spl les/ /spl Delta//sup 2/ for any simple graph with the maximum degree /spl Delta//spl ges/2. This paper considers the graphs formed by the Cartesian product and the composition of two graphs. The new graph satisfies the conjecture above in both cases(with minor exceptions).     

有限域上m序列与其采样序列的互相关性

本文研究了有限域GF(p)上的m序列与其采样序列之间的互相关函数C_d(t),得到以下结论:(1)当采样因子d= pⁿ+1 p+1 + pⁿ-1 2 ,n为奇数且p≡3(mod 4)时,|1+C_d(t)| 1+p 2 pⁿ ,从而解决了Muller在文献 中提出的一个公开问题,并将文献[1]中的p=3时的结论推广为一般情形;(2)当d= pⁿ+1 p+1 ,n为奇数且p≡3(mod 4)时,C_d(t)∈{-1,-1+ p n+1 -1- pⁿ⁺¹ };(3)在以上两种情况下,对|1+C_d(t)|关于t的分布进行了研究,结果表明,当p很大时,|1+C_d(t)|取最大值的概率很小.     

ESD circuit model based protection network optimisation for extended-voltage NMOS drivers

New snapback circuit models for drain extended MOS (DEMOS) and complementary DEMOS-SCR structures used for ESD protection in high-voltage tolerant applications have been developed. The models were experimentally validated in a standard 0.35 μm CMOS process which requires 20 V compatible structures. It is shown that the new ESD models provide accurate representation of the structure breakdown, turn-on behaviour into conductivity modulation mode and dV/dt triggering effect, both in static and ESD transient conditions. A major application of this model is for initial ESD optimisation of complex mixed voltage analog circuits.     

Method of rapid numerical calculation of transient processes in a thyristor

A method is proposed for the rapid numerical calculation (less than 0.5 min with an IBM 370 computer) of thyristor behaviour during transient operation. The dV/dt blocking capability, the gate triggering and the anode-current turnoff are simulated. The results obtained are compared with experimental results.     

New class of nonlinear systematic error detecting codes

A code C detects error e with probability 1-Q(e),ifQ(e) is a fraction of codewords y such that y, y+e/spl isin/C. We present a class of optimal nonlinear q-ary systematic (n, q/sup k/)-codes (robust codes) minimizing over all (n, q/sup k/)-codes the maximum of Q(e) for nonzero e. We also show that any linear (n, q/sup k/)-code V with n /spl les/2k can be modified into a nonlinear (n, q/sup k/)-code C/sub v/ with simple encoding and decoding procedures, such that the set E={e|Q(e)=1} of undetected errors for C/sub v/ is a (k-r)-dimensional subspace of V (|E|=q/sup k-r/ instead of q/sup k/ for V). For the remaining q/sup n/-q/sup k-r/ nonzero errors, Q(e)/spl les/q/sup -r/for q/spl ges/3 and Q(e)/spl les/ 2/sup -r+1/ for q=2.     

Digital Enhancement of the Peripheral Admittance Plethysmogram

Limb segment pulse volume (PV) is the maximum change in the volume (V) of a limb segment during the cardiac cycle. Peak net inflow (PNI) is the maximum value of dV/dt during the cardiac cycle. These parameters are difficult to measure because they are so small (PV is approximately 0.0003 ×V). As a result, conventional analog plethysmographic measurements of PV and PNI are inherently inaccurate and difficult to reproduce. A digital enhancement (DE) technique using selective signal averaging to improve PV and PNI reproducibility is described.     

An EBS (electron bombarded semiconductor) high-current pulse amplifier

An EBS (electron bombarded semiconductor) pulse amplifier which generates high-current fast-risetime variable-width pulses into low impedance loads is described. Current pulses of 100 A into a 1-Ω load have been obtained with a risetime of 2.2 ns. A di/dt of 40 000 A/µs and a dV/dt of 71 000 V/µs have been obtained. Pulse lengths to 1 µs at 0.1-percent duty have been achieved. The risetime and peak current capabilities are presently limited by internal circuit parasitics. Without parasistics, the theoretical peak output capabilities for this EBS are 340 A with a di/dt of 6 × 10⁵A/µs.     

双包层手征光纤的色散特性

在对双包层手征光纤(W型)进行解析求解的基础上，用数值计算方法研究了纤芯和内外包层的手征参数和内包层厚度对模式色散特性的影响，给出了双包层手征光纤中基模的归一化传播常数b、群延迟d(Vb)／dV和波导色散Vd2(V6)／dV2随纤芯和内外包层的手征参数和内包层厚度的变化关系曲线。结果表明在双包层光纤的纤芯和内外包层中引入手征，可以极大地改变光纤中基模的色散特性，特别是内包层厚度不同时，色散特性也极为不同．     

Hypothesis testing of complex covariance matrices

Letcal ybe a mean zero complex stationary Gaussian signal process depending on a vector parametertheta prime = { theta_{1}, theta_{2}, theta_{3} }whose components represent parameters of the covariance function R(r) ofcal y. These parameters are chosen astheta_{1} = R(0), theta_{2} = |R( tau )| /R(0), theta_{3} =phase ofR( tau), and they are simply related to the parameters of the spectral density ofcal y. This paper is concerned with the determination of most powerful (MP) tests that distinguish between random signals having different covariance functions. The tests are based uponNcorrelated pairs of independent observations oncal y. Although the MP test that distinguishes betweentheta = theta_{o}and the alternative hypothesistheta = theta_{1}has been solved previously [11], the problem of identifying the random signals is often complicated by the fact that the signal powertheta_{1} = R(0)is not a distinguishing feature of either hypothesis. This paper determines the MP invariant test that delineates between the composite hypothesislambda equiv R( tau)/R(0) = lambda_{0}and the composite alternativelambda = lambda_{1}. In addition, the uniformly MP invariant test that distinguishes between the composite hypothesestheta_{2} <_{=} | lambda_{o} |andtheta_{2} > | lambda_{0} |has also been found. In all cases, exact probability distributions have been obtained.     

无氧溅射方法制备OLED的ITO透明电极

采用氧化铟锡(ITO)合金材料作为靶材,通过射频磁控溅射制备ITO膜.将获得的ITO膜应用于结构为ITO/m-MTDATA(30 nm)/NPB(20 nm)/Alq3(50 nm)LiF(0.8 nm)/Al(100 nm)的有机电致发光器件(OLED),得到了最大亮度为11560 cd/m2(电压为25V)、最大效率为2.52 cd/A(电压为14 V)的结果.为了获得双面发光,制作了结构为ITO/m-MTDATA(30 nm)/NPB(20 nm)/Alq3(50 nm)LiF(0.8 nm)/Al(20 nm)/ITO(50 nm)的器件,其阳极出光的最大亮度为14460 cd/m2(电压为18V)、最大效率为2.16 cd/A(电压为12V),阴极出光的最大亮度为1 263 cd/m2(电压为19 V)、最大效率为0.26 cd/A(电压为16V).     

A linear-time algorithm for computing K-terminal reliability onproper interval graphs

Consider a probabilistic graph in which the edges are perfectly reliable, but vertices can fail with some known probabilities. The K-terminal reliability of this graph is the probability that a given set of vertices K is connected. This reliability problem is #P-complete for general graphs, and remains #P-complete for chordal graphs and comparability graphs. This paper presents a linear-time algorithm for computing K-terminal reliability on proper interval graphs. A graph G = (V, E) is a proper interval graph if there exists a mapping from V to a class of intervals I of the real line with the properties that two vertices in G are adjacent if their corresponding intervals overlap and no interval in I properly contains another. This algorithm can be implemented in O(|V| + |E|) time     

The redundancy of source coding with a fidelity criterion .II.Coding at a fixed rate level with unknown statistics

The redundancy problem of universal lossy source coding at a fixed rate level is considered. Under some condition on the single-letter distortion measure, which implies that the cardinality K of the reproduction alphabet is not greater than the cardinality J of the source alphabet, it is shown that the redundancy of universally coding memoryless sources p by nth-order block codes of rate R goes like |(∂/∂R)d(p,R)|Kln n/2n+o(ln n/n) for all memoryless sources p except a set whose volume goes to 0 as the block length n goes to infinity, where d(p,R) denotes the distortion rate function of p. Specifically, for any sequence {C_n}_n=1^∞ of block codes, where C_n is an nth-order block code at the fixed rate R, and any ϵ>0, the redundancy D_n(C _n,p) of C_n for p is greater than or equal to |(∂/∂R)d(p,R)|(K-ϵ)ln n/2n for all p satisfying some regular conditions except a set whose volume goes to 0 as n→∞. On the other hand, there exists a sequence {C_n}_n=1^∞ of block codes at the rate R such that for any p satisfying some regular conditions, the super limit of D_n(C_n,p)|(ln n/n) is less than or equal to |(∂/∂R)d(p,R)|K/2     

A definition of pulse delay in the presence of distortion

It is proposed that pulse delay, in the presence of distortion, be defined as ∫TX(T) dT/∫X(T) dT where X(T) = ∫|m1(t - T)|²|m2(t)|²dt is the cross correlation of the squares of the magnitudes of the transmitted and received pulse modulation. In the absence of the distortion, the definition reduces to the group delay.     

Subharmonic generation and the trapped-plasma mode in avalanching silicon p+-n-n+junctions

Experimental evidence is presented which distinguishes two mechanisms whereby an avalanche diode can efficiently generate microwaves at transit angles below those of classical transit-time oscillations. Measurements of external current waveforms and subsequent calculations of terminal voltage waveforms demonstrated that efficient generation (η ∼10 percent) of microwaves was possible at sub-harmonics of transit-time excitations. This subharmonic generation occurred when various harmonic components interacted such that the peak total voltage was delayed with respect to the fundamental. In such cases of multiharmonic synergetic excitations, the peak displacement currents were less than 0.25 of that required for avalanche shock-front initiation. The distinguishing features of high-efficiency operation (η ∼50 percent) were found to be completely consistent with a trapped-plasma mode interpretation. Experimental external current and dV/dt waveforms have substantiated Evans' circuit analysis [28]. dV/dt waveforms indicated peak displacement currents at breakdown which were on the order of 1.5 times that required for shock-front initiation. Approximate conduction current waveforms exhibited larger currents during the shock-front transit than during the extraction period. General features were consistent with calculations made by Cottam [29]. Circuit characteristics for both subharmonic generation and the trapped-plasma mode were similar. Circuit analysis also indicated the critical importance of each separate harmonic of a trapped-plasma mode fundamental. Harmonic generation utilizing the trapped-plasma mode enabled an extension of the upper bound of the frequency of efficient generation.     

A distributed algorithm for delay-constrained unicast routing

We study the NP-hard delay-constrained least cost (DCLC) path problem. A solution to this problem is needed to provide real-time communication service to connection-oriented applications, such as video and voice. We propose a simple, distributed heuristic solution, called the delay-constrained unicast routing (DCUR) algorithm, DCUR requires limited network state information to be kept at each node: a cost vector and a delay vector. We prove DCUR's correctness by showing that it is always capable of constructing a loop-free delay-constrained path within finite time, if such a path exists. The worst case message complexity of DCUR is O(|V|²) messages, where |V| is the number of nodes. However, simulation results show that, on the average, DCUR requires much fewer messages. Therefore, DCUR scales well to large networks. We also use simulation to compare DCUR to the optimal algorithm, and to the least delay path algorithm. Our results show that DCUR's path costs are within 10% of those of the optimal solution