Object-oriented Design of Reusable Model Libraries of Hybrid Dynamic Systems – Part One: A Design Methodology

An object-oriented methodology for the design of reusable model libraries, dedicated to the composition of hybrid simulation models, is proposed. It takes into consideration all the phases of the library life cycle: design, programming, maintenance, modifications, extension, etc. The methodology distinguishes between the role of the library designers and the role of the library users. One of its main goals is guaranteeing that the users are able to use the libraries without having to know their internal details. In particular, users should not be confronted with numerical problems. The library designers should guarantee the numerical efficiency of the models based on the library predefined-models. In this respect, some of the numerical aspects of the model library design are discussed. The concept of library design rules is introduced as the cornerstone of the proposed methodology.     

The Groups of Symmetric Genus σ ≤ 8

Let G be a finite group. The symmetric genus σ (G) is the minimum genus of any compact Riemann surface on which G acts faithfully as a group of automorphisms. Here we classify the groups of symmetric genus σ, for all values of σ such that 4 ≤ σ ≤ 8. In addition, we obtain some general results about the partial presentations that groups acting on surfaces must have. We show that a group with even genus and no “large order” elements in its Sylow 2-subgroup has restrictions on its Sylow 2-subgroup. As a consequence, we show that if G is a 2-group with positive symmetric genus, then σ(G) is odd. The software package MAGMA was employed to help with the calculations, and the MAGMA library of small groups was essential to the classification.     

Virtual Tokamak library software

We describe the concept of the Virtual Tokamak library, its functionality, major components, and method of use. The library is designed to predict, support, and interpret experiments as well as handle measurements on tokamak instruments implementing the idea of energy production on the basis of controlled thermonuclear fusion. The library software consists of an interactive graphic shell and a number of interrelated computer codes simulating various processes in the tokamak plasma, its structural elements, diagnostics and control system. This is a specific implementation of advanced information technologies including Internet technologies and approaches of distributed computations in the field of the mathematical modeling of plasma. The Virtual Tokamak is unique in terms of combined application and system software.     

BPPLIB: a library for bin packing and cutting stock problems

The bin packing problem (and its variant, the cutting stock problem) is among the most intensively studied combinatorial optimization problems. We present a library of computer codes, benchmark instances, and pointers to relevant articles for these two problems. The library is available at http://or.dei.unibo.it/library/bpplib. The computer code section includes twelve programs: seven are directly downloadable from the library page, while for the remaining five we provide addresses where they can be obtained or downloaded. Some of the codes for which we provide an original C++ implementation need an integer linear programming solver. For such cases, the library provides two versions: one that uses the commercial solver CPLEX, and one that uses the freeware solver SCIP. The benchmark section provides over six thousands instances (partly coming from the literature and partly randomly generated), together with the corresponding solutions. Instances that are difficult to solve to proven optimality are included. The library also includes a BibTeX file of more than 150 references on this topic and an interactive visual tool to manually solve bin packing and cutting stock instances. We conclude this work by reporting the results of new computational experiments on a number of computer codes and benchmark instances.     

Constructing an international library: The collections of journals in Turin's Special Mathematics Library

The Special Mathematics Library of Turin University, founded in 1883, was fundamental in the development of two research schools under the leadership of C. Segre and G. Peano. First founded to house a growing collection of international journals acquired through both purchase and exchange from publishing centres worldwide, it later evolved into a ‘presence library’ modelled on the legendary Lesezimmer in Göttingen. A systematic study of the library's history and its directors' policies provides interesting insights into the various aspects of the international circulation of journals and their use at different times and in various contexts in Turin (Turin Academy of Sciences, Società di cultura, national university library, etc.).     

Software to support numerical analysis teaching

This paper describes a Fortran90 library designed to support the teaching of numerical analysis and its applications. As well as covering traditional material it introduces recent and important ideas in numerical computation such as interval arithmetic and automatic differentiation. The library rests on a module realpac which provides real arithmetic in a range of precisions with a choice of rounding strategies. This, in turn, supports the implementation of an interval arithmetic module intpac. Derived data types and overloaded operations help inexperienced users to interface with unfamiliar data types such as intervals. The library also includes more conventional modules such as lepac for solving linear systems and minpac for nonlinear optimization. These, however, can be enhanced by being linked to more sophisticated tools for sparse matrix handling and automatic differentiation. As well as showing the main structure and scope of the software, the paper mentions some exercises that have successfully been performed by students.     

Recent additions to SLEPc,the Scalable Library for Eigenvalue Problem computations

SLEPc is a software library for the solution of large, sparse eigenvalue problems on parallel computers. We have recently extended its functionality by incorporating a Krylov-Schur eigensolver and a module for singular value computation. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

The nonequispaced FFT on graphics processing units

Without doubt, the fast Fourier transform (FFT) belongs to the algorithms with large impact on science and engineering. By appropriate approximations, this scheme has been generalized for arbitrary spatial sampling points. This so called nonequispaced FFT is the core of the sequential NFFT3 library and we discuss its computational costs in detail. On the other hand, programmable graphics processing units have evolved into highly parallel, multithreaded, manycore processors with enormous computational capacity and very high memory bandwidth. By means of the so called Compute Unified Device Architecture (CUDA), we parallelized the nonequispaced FFT using the CUDA FFT library and a dedicated parallelization of the approximation scheme. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

模糊综合评价法在高校图书馆评估中的应用

简述了对高校图书馆评估的意义,依据教育部2003年2月12日颁布的《普通高等学校图书馆评估指标(征求意见稿)》确定的指标体系,运用模糊数学中综合评价的方法对高校图书馆进行评估,并运用"最大隶属度"原则评价出高校图书馆的状况.     

A library for continuous convex separable quadratic knapsack problems

The Continuous Convex Separable Quadratic Knapsack problem (CQKnP) is an easy but useful model that has very many different applications. Although the problem can be solved quickly, it must typically be solved very many times within approaches to (much) more difficult models; hence an efficient solution approach is required. We present and discuss a small open-source library for its solution that we have recently developed and distributed.     

面向对象有限元分析程序设计及其VC++实现

采用面向对象的方法确定了有限元分析过程的对象、对象间的关系及类库,并使用VC++语言,利用其MFC类库实现了有限元分析类库及相应窗口图形化界面的程序体序。程序系统具有良好的可靠性,可再用性和可扩充性。为进一步开发大型、通用、功能性强的面向对象的有限元分析软件提供参考。     

Development of a Toolbox for Model‐Based Real‐Time Simulation and Analysis of Legged Robots

Multibody systems such as legged robots require sophisticated and efficient methods for their modeling, control and simulation. This paper discusses the development of a software library based on modern tools such as C++, OpenGL and XML for highly efficient dynamics modeling. A primary focus lies on modularity permitting its easy extensibility in connection with different actuation and contact models, optimization algorithms, localized and centralized on‐line control schemes as well as animation and simulation environments.     

Embedding learning capability in Lagrangean relaxation: An application to the travelling salesman problem

This paper presents an effective procedure that finds lower bounds for the travelling salesman problem based on the 1-tree using a learning-based Lagrangian relaxation technique. The procedure can dynamically alter its step-size depending upon its previous iterations. Along with having the capability of expansion–contraction, the procedure performs a learning process in which Lagrange multipliers are influenced by a weighted cost function of their neighbouring nodes. In analogy with simulated annealing paradigm, here a learning process is equivalent to escaping local optimality via exploiting the structure of the problem. Computational results conducted on Euclidean benchmarks from the TSPLIB library show that the procedure is very effective.     

Primitive symmetric designs with up to 2500 points

By this article we conclude the construction of all primitive ( v, k,λ ) symmetric designs with v < 2500 , up to a few unsolved cases. Complementary to the designs with prime power number of points published previously, here we give 55 primitive symmetric designs with v ≠ p ^m , p prime and m positive integer, together with the analysis of their full automorphism groups. The research involves programming and wide‐range computations. We make use of the software package GAP and the library of primitive groups which it contains. © 2011 Wiley Periodicals, Inc. J Combin Designs 19:463‐474, 2011     

ARMMS: Analogical reasoning model management system for multicriteria vehicle scheduling

The transportation industry problem of scheduling vehicles combines the spatial characteristics of routing with time domain considerations of activity schedules. The problem is complex because of the numerous interacting constraints in the spatial and time domains. Further, some of the constraints are flexible and some arise in real-time. The scheduling problem is often presented with multiple objectives that are not all economic in nature and which can be contradictory to one another. In response to these needs, this paper describes an analogical reasoning model management system, called ARMMS, designed in the domain of vehicle scheduling. ARMMS consists of knowledge bases and data bases, a truth maintenance system, a user interface, an inference engine, a learning mechanism, and a model library. Given a scheduling problem, ARMMS searches its memory for solutions. If no solution is available, ARMMS falls back on an analogical problem solving approach in which similar experience can be recalled, and solutions to new, but similar, problems can be constructed. If no similar experience exists, ARMMS intelligently selects an appropriate algorithmic model from its model library, based on the input parameters and problem type, to solve the given problem. By combining experts' knowledge, analogical problem-solving approaches, and algorithmic methods, ARMMS provides an efficient problem-solving approach for vehicle scheduling and routing. ARMMS is also a feasible base for the development of intelligent model management systems.     

效用函数理论及其应用研究

分析了效用函数理论,提出了图书效用函数,并分析其性质.得出图书最大效用化的约束条件.指导图书馆文献资源建设.     

Bond graph modelling of marine power systems

The main motivation for writing this article is to develop a model library for an All-Electric Ship that gives an opportunity to simulate both existing and new machinery systems without having to remodel the entire system each time. The model library should support the process of modelling and reuse, while also emphasizing openness to brace the modeller during the development and refinement phase. The bond graph approach is good when it comes to the physical modelling of systems and is a good tool for combining different energy domains to better help in understanding the system. In addition, a bond graph is a powerful method to find dependencies between various components. Using a causal analysis, any problems in the model, for example, algebraic constrains or dependent system variables, will be detected, and the necessary remodelling may be performed to handle such problems. The bond graph approach is therefore used when developing the component library. The component library consists of selected power producers such as diesel and gas engines, fuel cell and synchronous generator and power consumers such as asynchronous motor with a voltage source converter in addition to a generic load used for hotel and auxiliary loads. The library also consists of a ship model and propeller models.     

Properties of the promotion Markov chain on linear extensions

The Tsetlin library is a very well-studied model for the way an arrangement of books on a library shelf evolves over time. One of the most interesting properties of this Markov chain is that its spectrum can be computed exactly and that the eigenvalues are linear in the transition probabilities. This result has been generalized in different ways by various people. In this work, we investigate one of the generalizations given by the extended promotion Markov chain on linear extensions of a poset P introduced by Ayyer et al. (J Algebr Comb 39(4):853–881, 2014). They showed that if the poset P is a rooted forest, the transition matrix of this Markov chain has eigenvalues that are linear in the transition probabilities and described their multiplicities. We show that the same property holds for a larger class of posets for which we also derive convergence to stationarity results.     

A bare-bones ant colony optimization algorithm that performs competitively on the sequential ordering problem

EigenAnt is a bare-bones ant colony optimization algorithm that has been proven to converge to the optimal solution under certain conditions. In this paper, we extend EigenAnt to the sequential ordering problem (SOP), comparing its performance to Gambardella et al.’s enhanced ant colony system (EACS), a model that has been found to have state-of-the-art performance on the SOP. Our experimental results, using the SOPLIB2006 instance library, indicate that there is no statistically significant difference in performance between our proposed method and the state-of-the-art EACS method.