Protecting equipment against electromagnetic noise in power-supply networks

The problems of how to secure the electromagnetic compatibility of technological equipment with the help of resonance transfilters (matching filter) are examined. An equivalent circuit and mathematical model for transfilters are developed. The tests results verify the adequacy of the mathematical model.     

Determination of oxidizing anions in explosive mixtures by phase transfer

Inorganic oxidizing agents are used in various explosive mixtures that are analysed by analytical chemists. Among them are dynamites, ANFO, black powder, match heads, pyrotechnical devices and home-made bombs. The crucial step in post explosion analysis is the extraction and purification of the explosive residues from the debris. A unique, fast and selective extraction technique for inorganic oxidizing agents is described in this paper. The debris are first extracted with water to yield an aqueous solution of the ions. Oxidizing anions such as nitrate and chlorate, are selectively transfered into the organic phase by the use of lipophilic quarternary ammonium cations. Other anions such as carbonate, sulphate and nitrite are not extracted into the organic phase under these conditions. The extracted anions are then identified by infra-red spectrometry and chemical spot tests.     

Optimization methods in inverse problems and applications to science and engineering

Optimization and Engineering -     

Self-stabilizing extensions for meassage-passing systems

Summary A self-stabilizing program eventually resumes normal behavior even if excution begins in, an abnormal initial state. In this paper, we explore the possibility of extending an arbitrary program into a self-stabilizing one. Our contributions are: (1) a formal definition of the concept of one program being aself-stabilizing extension of another; (2) a characterization of what properties may hold in such extensions; (3) a demonstration of the possibility of mechanically creating such extensions. The computtional model used is that of an asynchronous distributed message-passing system whose communication topology is an arbitrary graph. We contrast the difficulties of self-stabilization in thismodel with those of themore common shared-memory models. Shmuel Katz received his B.A. in Mathematics and Englisch Literature from U.C.L.A., and his M.Sc. and Ph.D. in Computer Science (1976) from the Weizmann Institute in Rechovot, Israel. From 1976 to 1981 he was a research at the IBM Israel Scientific Center. Presently, he is an Associate Professor in the Computer Science Department at the Technion in Haifa, Israel. In 1977–78 he visited for a year at the University of California, Berkeley, and in 1984–85 was at the University of Texas at Austin. He has been a consultant and vistor at the MCC Software Technology Program, and in 1988–89 was a visiting scientist at the IBM Watson Research Center. His research interests include the methodology of programming, specification methods, program verification and semantics, distributed programming, data structure, and programming languages. Kenneth J. Pery has performed research in the area of distributed computing since obtaining Masters and Doctorate degrees in Computer Science from Cornell Univesity. His current interest is in studying problems of a partical nature in a formal context. He was graduated from Princeton University in 1979 with a B.S.E. degree in Electrical Engineering and Computer Science.The Research of this author was partially supported by Research Grant 120-749 and the Argentinian Research Fund at the Technion     

Efficient broadcasting in radio networks with long-range interference

We study broadcasting, also known as one-to-all communication, in synchronous radio networks with known topology modeled by undirected (symmetric) graphs, where the interference range of a node is likely exceeding its transmission range. In this model, if two nodes are connected by a transmission edge they can communicate directly. On the other hand, if two nodes are connected by an interference edge they cannot communicate directly and transmission of one node disables recipience of any message at the other node. For a network $G,$ we term the smallest integer $d$ , s.t., for any interference edge $e$ there exists a simple path formed of at most $d$ transmission edges connecting the endpoints of $e$ as its interference distance $d_I$ . In this model the schedule of transmissions is precomputed in advance. It is based on the full knowledge of the size and the topology (including location of transmission and interference edges) of the network. We are interested in the design of fast broadcasting schedules that are energy efficient, i.e., based on a bounded number of transmissions executed at each node. We adopt $n$ as the number of nodes, $D_T$ is the diameter of the subnetwork induced by the transmission edges, and $\varDelta $ refers to the maximum combined degree (formed of transmission and interference edges) of the network. We contribute the following new results: (1) We prove that for networks with the interference distance $d_I\ge 2$ any broadcasting schedule requires at least $D_T+\varOmega (\varDelta \cdot \frac{\log {n}}{\log {\varDelta }})$ rounds. (2) We provide for networks modeled by bipartite graphs an algorithm that computes $1$ -shot (each node transmits at most once) broadcasting schedules of length $O(\varDelta \cdot \log {n})$ . (3) The main result of the paper is an algorithm that computes a $1$ -shot broadcasting schedule of length at most $4 \cdot D_T + O(\varDelta \cdot d_I \cdot \log ^4{n})$ for networks with arbitrary topology. Note that in view of the lower bound from (1) if $d_I$ is poly-logarithmic in $n$ this broadcast schedule is a poly-logarithmic factor away from the optimal solution.     

Calculus of the modulus of continuity for nonconcave functions and applications

For a continuous nonconcave function on [a,b] we prove that the modulus of continuity of f satisfies ω(f;δ)=max{|f(a+δ)−f(a)|; |f(b−δ)−f(b)|}, for δ sufficiently small. Some applications in approximation theory are given.     

Fuzzy and probability vectors as elements of a vector space

The problem of defining vector space operations on fuzzy and probability vectors is discussed. It is shown that such a definition is equivalent to choosing a 1-1 and onto mapping from the unit interval into the real axis. Although such a mapping cannot be continuous, it is suggested that under certain approximations a continuous mapping can be chosen. A characterization of some useful mappings with applications to image processing is also given.     

Specification of internal accounting controls in a database environment

This paper examines the problem of specifying database security controls in a manner such that the resulting segmentation of data and the patterns of access rights are consistent with traditional accounting concepts that govern segregation of duties. The mechanism we use for implementation of these controls in a relational accounting system is that of a “view” implemented on the Query-by-Example database management system. A number of examples are presented in detail and some further aspects of security and integrity constraints are discussed.