Cost optimization of cross-laminated timber panels in one-way bending

European Journal of Wood and Wood Products - For the purposes of structural design, cross-laminated timber (CLT) panels are typically chosen from tables detailing standardized layups. While this is...     

Dynamic routing in reentrant flexible manufacturing systems

Consider a flexible manufacturing system (FMS), with several parallel production lines. Each line is statistically balanced. Due to process time and yield variations, some workstations may be temporarily starved of parts during the FMS operation, while others may have too many. The purpose of the dynamic routing algorithm described here is to achieve real-time load balancing in a stochastic processing environment and thus to increase the performance of the system in throughput, workload balance and reduced work-in-process queues. We formulate the problem and develop an optimal stationary policy (for two lines that have a material handling transport between them) based on the input buffer state of each station.     

Electing a leader in a ring with link failures

Summary We investigate the message complexity of electing a leader in a ring of asynchronous processors. Our work deviates from the previous works on electing a leader in that we consider the effect of link failures. A link is said to fail if some message sent through it never reaches its destination. We distinguish the case where n is known from the case n unknown. Our main result is a O(n · log n) algorithm for electing a leader on a n-processor ring (the case n is known).     

Efficient non‐linear reanalysis of skeletal structures using combined approximations

Non‐linear reanalysis of large‐scale structures usually involves much computational effort, because the set of non‐linear equations must be solved repeatedly during the solution process. Various approximations that are often used for linear reanalysis are not sufficiently accurate for non‐linear problems. In this study, solution procedures based on the combined approximations approach are developed and compared in terms of efficiency and accuracy. Various path‐independent non‐linear analysis and reanalysis problems are considered, including material non‐linearity, geometric non‐linearity and buckling analysis. Numerical examples demonstrate the effectiveness of the procedures presented. It is shown that in various cases accurate results can be achieved efficiently. Copyright © 2007 John Wiley & Sons, Ltd.     

A uniform-complexity treatment of encryption and zero-knowledge

We provide a treatment of encryption and zero-knowledge in terms of uniform complexity measures. This treatment is appropriate for cryptographic settings modeled by probabilistic polynomial-time machines. Our uniform treatment allows the construction of secure encryption schemes and zero-knowledge proof systems (for allNP) using only uniform complexity assumptions. We show that uniform variants of the two definitions of security, presented in the pioneering work of Goldwasser and Micali, are in fact equivalent. Such a result was known before only for nonuniform formalization. Nonuniformity is implicit in all previous treatments of zero-knowledge in the sense that a zero-knowledge proof is required to “leak no knowledge” onall instances. For practical purposes, it suffices to require that it isinfeasible to find instances on which a zero-knowledge proof “leaks knowledge.” We show how to construct such zero-knowledge proof systems for every language inNP, using only a uniform complexity assumption. Properties of uniformly zero-knowledge proofs are investigated and their utility is demonstrated. This research was partially supported by the Fund for Basic Research Administered by the Israeli Academy of Sciences and Humanities. Revision of this work was supported by Grant No. 89-00312 from the United States-Israel Binational Science Foundation (BSF), Jerusalem, Israel.     

A perfect zero-knowledge proof system for a problem equivalent to the discrete logarithm

An interactive proof system is calledperfect zero-knowledge if the probability distribution generated by any probabilistic polynomial-time verifier interacting with the prover on input theoremϕ, can be generated by another probabilistic polynomial-time machine which only getsϕ as input (and interacts with nobody!). In this paper we present aperfect zero-knowledge proof system for a decision problem which is computationally equivalent to the Discrete Logarithm Problem. Doing so we provide additional evidence to the belief thatperfect zero-knowledge proof systems exist in a nontrivial manner (i.e., for languages not inBPP). Our results extend to the logarithm problem in any finite Abelian group. This research was partially supported by the Fund for Basic Research Administered by the Israeli Academy of Sciences and Humanities. An early version of this paper appeared inAdvances in Cryptology —Crypto 88 (Proceedings), S. Goldwasser (ed.), pp. 57–70, Lecture Notes in Computer Science, vol. 403, Springer-Verlag, Berlin, 1990.     

解读DOCSIS 2.0技术

新的应用是否需要新的技术?或者，新的技术是否会产生新的应用?在不同的情况下，这一由来已久的问题的答案也各不相同。但就有线宽带市场而言，对这两个问题的回答都是肯定的。     

Pediatric flexible bronchoscopy

Between 1993-1996, 200 pediatric flexible bronchoscopies were performed. Indications were: chronic cough (158 children), persistent pulmonary infiltrates (89), recurrent stridor (28), suspected tracheobronchial foreign body (20), suspected tuberculosis (17) and hemoptysis (3). Some children had more than 1 indication. 124 patients were boys (mean 4.18 +/- 2.86 years; range 1 month-15 years) and 76 were girls (mean 4.39 +/- 2.7 years; range 4 months-15 years). The procedure included direct vision recorded by video-camera and bronchoalveolar lavage; the lavage fluid was sent for culture, Gram and Ziehl-Nielsen strains and for cytology. There were a few minor side effects: mild stridor which resolved within a few hours (10 children) and transient fever (3). This simple, flexible instrument was effective and helpful in the diagnosis and treatment of children with respiratory symptoms in a secondary hospital facility.