Semantics and technologies in modern design of interior stairs

Use of metal in the design of interior stairs presents new features for shaping, and can be implemented using different technologies. The article discusses the features of design and production technologies of forged metal spiral staircase considering the image semantics based on the historical and cultural heritage. To achieve the objective was applied structural-semantic method (to identify the organization of structure and semantic features of the artistic image), engineering methods (to justify the construction of the object), anthropometry method and ergonomics (to provide usability), methods of comparative analysis (to reveale the features of the way the ladder in different periods of culture). According to the research results are as follows. Was revealed the semantics influence on the design of interior staircase that is based on the World Tree image. Also was suggested rational calculation of steps to ensure the required strength. And finally was presented technology, providing the realization of the artistic image. In the practical part of the work is presented version of forged staircase

A New Parallel Approach to the Constrained Two-Dimensional Cutting Stock Problem

In this paper we present a new parallelization of an efficient best-first branch-and-bound algorithm to solve the constrained two-dimensional single stock guillotine cutting stock problem (CSP) to optimality. The underlying sequential branch-and-bound algorithm is based on an exact version of Wang's heuristic suggested by Viswanathan and Bagchi. In our algorithm we improve the upper bound and introduce duplicate pruning. For an efficient parallelization we developed a special communication structure, as due to the unusual branching strategy and detection of duplicates a standard parallelization of the branch-and-bound approach cannot be applied to this problem. This structure allows a dynamic and fully distributed load-balancing using a direct neighbor strategy. Computational results on two different parallel systems are presented. The implementation is system-independent using the portable parallel branch-and-bound library (PPBB-LIB) developed in Paderborn and can easi..

Performance Evaluation of Load Distribution Strategies in Parallel Branch and Bound Computations

Load distribution is essential for efficient use of processors in parallel branch-and-bound computations because the computation generates and consumes non-uniform subproblems at runtime. This paper presents six decentralized load distribution strategies. They are incorporated in a runtime support system, and evaluated in the solution of set partitioning problems on two parallel computer systems. It is observed that local averaging strategies outperform the randomized allocation and the Acwn algorithm significantly in large scale system. They lead to an almost linear speedup in a PowerPC-based system with up to 32 nodes and to a speedup of 146.8 in a Transputer-based system with 256 nodes. It is also observed that the randomized allocation and the Acwn algorithm can be improved by 10% to 15% when the subproblem bound information is used in the decisionmaking. 1 Introduction Branch-and-bound is a well-known technique for solving combinatorial search problems [4]. Its basic scheme is t..

A Better Upper Bound on the Bisection Width of de Bruijn Networks

We approach the problem of bisectioning the de Bruijn network into two parts of equal size and minimal number of edges connecting the two parts (cross-edges). We introduce a general method that is based on required substrings. A partition is defined by taking as one part all the nodes containing a certain string and as the other part all the other nodes. This leads to good bisections for a large class of dimensions. The analysis of this method for a special kind of substrings enables us to compute for an infinite class of de Bruijn networks a bisection, that has asymptotically only 2 \Delta ln(2) \Delta 2 n =n cross-edges. This improves previously known bisections with 4 \Delta 2 n =n cross-edges. 1 Introduction The graph-bisection-problem is one of the best studied problems in graph theory. It has various important applications, for example in VLSI-layout [Len94] and in parallel computing [Lei92]. Given a graph G = (V; E) the bisection width fi(G) is the minimal number of edge..

A Better Upper Bound on the Bisection Width of de Bruijn Networks (Extended Abstract)

. We approach the problem of bisectioning the de Bruijn network into two parts of equal size and minimal number of edges connecting the two parts (cross-edges). We introduce a general method that is based on required substrings. A partition is defined by taking as one part all the nodes containing a certain string and as the other part all the other nodes. This leads to good bisections for a large class of dimensions. The analysis of this method for a special kind of substrings enables us to compute for an infinite class of de Bruijn networks a bisection, that has asymptotically only 2 \Delta ln(2) \Delta 2 n =n cross-edges. This improves previously known bisections with 4 \Delta 2 n =n cross-edges. 1 Introduction The graph-bisection-problem is one of the best studied problems in graph theory. It has various important applications, for example in VLSI-layout [Len94] and in parallel computing [Lei92]. Given a graph G = (V; E) the bisection width fi(G) is the minimal number of edge..