Two Algorithms for Determining the Most Reliable Path of a Network

This paper presents two algorithms for determining the most reliable paths of a communication network, taking into account both the reliabilities of nodes and links. A network is modeled by a linear graph. The first algorithm adapts a node labeling scheme; second is based on the shortest-path matrix algorithm. Both algorithms can be applied to oriented and nonoriented nonsymetric networks. The numerical examples confirm that both algorithms efficiently handle networks with hundreds of nodes and edges. The total amount of computation, expressed by the number of multiplications and comparisons, increases in the labeling procedure with the square of the number of nodes, and in the matrix method with the cube of the number of nodes.     

Failure analysis of the combat jet aircraft rudder shaft

This paper analyzes failure causes of the combat jet aircraft rudder shaft (RS) which occurred during the flight mission. A finite element method (FEM), utilized to determine the stress state of the RS subjected to hinge moment ultimate load, resulted in the high stress concentration sites around the rivet holes. The longitudinal crack was initiated from the corrosion pit in the zone of the rivet hole, where the fatigue beach marks were observed. The inner surface of the RS was heavily corroded. Moreover, pitting corrosion has destroyed approximately 50% of the wall thickness. Based on the presented results it was concluded that the failure of the RS had a character of fatigue combined with heavy corrosion. Therefore, it is recommended that the RS should be redesigned; the material changed into more corrosion resistant one and the maintenance procedure changed in order to avoid future similar failures.     

A timely detection of a coated board streak defect in subsampling conditions using monochrome vision system

This paper presents a study of an important improvement in an already installed monochrome vision system for detection of defects during coated board manufacture. This improvement allows the inspection system to detect targeted defect in subsampling conditions (i.e. Nyquist theorem is not satisfied). This improvement is accomplished entirely in the image processing software without the need for additional changes in the vision hardware. Processing software is optimized for SIMD instruction set requiring no improvement in the processing hardware. Results obtained by the use of this improved algorithm provide real time detection of the targeted defect that in turns enables elimination of the waist coated board.     

Isogeometric bending analysis of composite plates based on a higher-order shear deformation theory

This research paper presents an isogeometric plate finite element formulation for analysis of thick composite plates. Isogeometric finite element method which is based on non-uniform rational B-splines (NURBS) basis functions, is a novel numerical procedure developed to bridge the gap between CAD and FEM modeling of structures. In order to investigate the behavior of isogeometric plate elements under static loading, plate kinematics is based on third order shear deformation theory (TSDT) of Reddy, which is free from transverse shear locking. This paper discusses accurate transverse stress recovery procedures for TSDT isogeometric finite elements. Numerical experiments with quadratic, cubic and quartic elements are presented and obtained results are compared to other available ones.     

台北艺术中心

正为什么过去百年间最令人兴奋的剧场盛事总是发生在正规场所之外?建筑如何才能超越自身卑微的命运,摆脱那种限制各种可能的宿命?近年来,世界各地的演艺中心数目渐增,但不知何故,这些演艺中心似乎达成一种共识,呈现出雷同的空间组合:一座约2 000席的大型演艺厅和一个1 500席的中型剧院,再加上一个黑盒子剧场。标志性的外形掩饰以典型19世纪做法为基础的     

Synthesis of starch benzoate in aqueous media

Summary The results of investigating starch benzoate (SB) synthesis in aqueous media are presented in this study. Starch esterification with benzoyl chloride was performed in two steps, the first step being the alkalization of starch and the second step esterification. The influence of the concentration of reactants, reaction medium composition, temperature and time of synthesis on the degree of substitution (DS), degree of swelling in water and thermal stability of the synthesized starch benzoate was investigated. The optimal conditions for the synthesis of starch benzoate with degree of substitution from 0.23 to 1.76 were determined. It was shown that starch benzoate with a DS of 1.76 practically did not swell in water. However, starch benzoate is less thermally stable than native starch probably due to a change in the supermolecular order induced by the esterification reaction. Received: 18 March 2002/Revised version: 18 October 2002/ Accepted: 28 October 2002 Correspondence to Katarina Jeremić     

Epidemiology of accidental home fires in Montreal2

Accidental home fires usually start in areas of the dwelling where people spend most of their time. The most frequent causes of fires are related to the activities of the residents, smoking being the most common. Persons who have home fires are, on average, younger than their controls, have more children, smoke in bed more and stay at home less often during the day. Typically, they live in apartment buildings where there has already been a fire, have less space available, but enjoy more fire protection than the controls. Home fires have characteristic seasonal, weekly and hourly distributions, as well as preponderance for older areas of the city. They are usually discovered by residents, smoke leading to detection in most cases, and most often occupants use their own telephones to alert firemen. This happens “immediately” after the discovery and the firemen are at the scene within 10 minutes in 90% of all instances. Extent of damage seems to be dependant on the time that elapses between the onset and the discovery of fires. No single variable can explain the occurences of accidental home fires. Yet, there appears to exist a person-building susceptible profile in which personal characteristics take precedence. Smoke detectors should become mandatory. Anti-smoking efforts should be enhanced. More care is needed when designing electrical power supplies in dwellings.     

Selecting risk levels in chance-constrained reservoir operation modeling: A fuzzy set approach

Many modifications, extensions, discussions, and evaluations of chance-constrained reservoir operating models have been reported in the technical literature. Lack of economic data and the fact that the establishment of acceptable risk levels in these types of models involves a human factor with all its vagueness of perception, subjectivity, and attitudes may not permit proper application of either reliability or multiobjective programming approaches. This paper presents a unique methodology for handling a practical problem of selecting risk levels in chance-constrained reservoir operation modeling. The proposed methodology is based on fuzzy set theory. Two types of fuzzy sets are used in the formulation of the reservoir long-term planning model, one for constraints and one for the objective function. An iterative solution algorithm for deriving an optimal decision using fuzzy set operations and the chance-constrained approach is developed and presented. A practical application of the approach demonstrates the feasibility and efficiency of both the proposed approach and its iterative search procedure for selecting risk levels in chance-constrained reservoir modeling.