Numerical methods for optimization of nonlinear shell structures

A numerical method for the optimal design of nonlinear shell structures is presented. The nonlinearity is only geometrical and the external load is assumed to be conservative. The nonlinear shell is analysed using standard nonlinear shell finite elements with the displacements and the rotation of the shell normals as independent analysis variables. Shell thicknesses and cross-sectional dimensions of beam stiffeners are used as design variables. The nonlinear optimization problem is solved using a Newton barrier method. The usefulness of the proposed method is demonstrated on shallow stiffened shell structures exhibiting significant nonlinear response.Presented at NATO ASI Optimization of Large Structural Systems, Berchtesgaden, Sept. 23 – Oct. 4, 1991     

Exact analytical solutions for some popular benchmark problems in topology optimization

The aim of this paper is to provide the exact analytical truss solutions for some benchmark problems, which are often used as test examples in both discretized layout optimization of trusses and variable topology (or generalized) shape optimization of perforated plates under plane stress.     

Shape optimization using adaptive high-order finite elements

In recent years, the state of the art in shape optimization has advanced due to new approaches proposed by various researchers. A fundamental difficulty in shape optimization is that the original finite element mesh may become invalid during large shape changes. Automatic remeshing and velocity field approaches are most commonly used for conventionalh-type finite element analysis to address this problem.In this paper, we describe a different approach to shape optimization based on the use of high-orderp-type finite elements tightly coupled to a parameterized computational geometry module. The advantages of this approach are as follows.Accurate results can be obtained with much fewer finite elements, so large shape changes are possible without remeshing.Automatic adaptive analysis may be performed so that accurate results are achieved at each step of the optimization process.Since the elements derive their geometric mapping from the underlying geometry, the fundamental equivalent of velocity field element shape updating may be readily achieved.Results are presented for sizing and shape optimization with this approach and contrasted with previous results from the literature.     

Three-dimensional micro-structures consisting of high aspect ratio inclined micro-pillars fabricated by simple photolithography

This paper presents a fabrication method of three-dimensional micro-structures consisting of high aspect ratio inclined micro-pillars using simple photolithography. The width and height of micro-pillars were 10 m and 200 m (the aspect ratio was about 20). The SU-8 coated on the Cr patterned Pyrex glass substrate was exposed from the backside with an angle to fabricate inclined micro-pillars. The 3-D micro-structures were fabricated by repeating the backside exposure with different angles. The shape of the micro-structure was defined by the number of exposures and the UV irradiation angles. The complicated micro-structures were fabricated by multi-angle exposures around two axes, as well as around one axis.This work was supported by: the Japanese Ministry of Education, Culture, Sport, Science and Technology Grant-in-Aids for COE Research of Waseda University, Scientific Research Priority Area (B) No. 13124209, Japan Society for the Promotion Science Grant-in-Aids for Creative Scientific Research No. 13BS0024, Nanotechnology Support Project of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) Japan, 21COE Practical Nano-Chemistry from MEXT Japan and Waseda University Grant for Special Research Project Individual Research No. 2002A-865.     

Informatik als Grundbildung

Informatik als Grundbildung wird als eine methodische Vorbereitung der Schüler auf einen Informatikunterricht an allgemeinbildenden Schulen neben eine sprachliche, mathematische und naturwissenschaftliche Grundbildung gestellt [5]. Das Gebiet wird in sechs Teilen vorgetragen. Teil I behandelte das Thema Schema und Ausprägung. Der vorliegende Teil II ist Elementarsätzen einer Rationalen Grammatik gewidmet. Der als nächstes folgende Teil III Gleichheit und Abstraktion stellt das Abstraktionsprinzip in den Mittelpunkt der Betrachtungen.     

Bubble method for topology and shape optimization of structures

This paper addresses a novel method of topology and shape optimization. The basic idea is the iterative positioning of new holes (so-called bubbles) into the present structure of the component. This concept is therefore called the bubble method. The iterative positioning of new bubbles is carried out by means of different methods, among others by solving a variational problem. The insertion of a new bubble leads to a change of the class of topology. For these different classes of topology, hierarchically structured shape optimizations that determine the optimal shape of the current bubble, as well as the other variable boundaries, are carried out.     

Spectrographic analysis and patterns in pronunciation

Though there are good reasons to improve instruction in pronunciation, the teaching of pronunciation has lost popularity among language teachers. This is because the traditional indirect analyses of sounds according to places and manners of articulation are clumsy when applied to classroom teaching. By shifting the focus of instruction to the direct feedback of real-time acoustic analysis in the visual mode, instructors are free from the complex and often unproductive terminology of articulatory phonetics, and students are free from the burden of translating instructors' general comments such as try again or repeat after me into plans for specific changes. Garry Molholt is Assistant Professor of Linguistics and English as a Second Language, and Coordinator of Computer Assisted Instruction. His research interests are the applications of speech processing to instruction in the acquisition of second language phonology. He has published Computer Assisted Instruction in Pronunciation for Chinese Speakers of American English, in TESOL Quarterly, and (with Ari Presler), Correlation between Human and Machine Ratings of Test of Spoken English Reading Passages, in Technology and Language Testing.     

Self-Repairing Mechanical Systems

This paper reviews several types of self-repairing systems developed in the Mechanical Engineering Laboratory. We have developed a modular system capable of self-assembly and self-repair. The former means a set of units can form a given shape of the system without outside help; the latter means the system restores the original shape if an arbitrary part of the system is cut off. We show both two-dimensional and three-dimensional unit designs, and distributed algorithms for the units.     

Multicriterion optimization of complex systems with parameters ranked by descending importance

A multicriterion optimization method is proposed for complex systems with parameters ranked by descending importance. This method requires weaker expert estimates for choosing an optimal alternative from the set of equally good solutions by formal specification of functional dependence between ranked parameter weights.Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 167–170, November–December, 1991.     

Deterministic sequential functions

The simple rational partial functions accepted by generalized sequential machines are shown to coincide with the compositions _P ^–1 , where _P consists of the prefix codings. The rational functions accepted by generalized sequential machines are proved to coincide with the compositions _P ^–1 , where is the family of endmarkers and is the family of removals of endmarkers. (The compositions are read from left to right). We also show that _P ^–1 is the family of the subsequential functions.This work was partially supported by the Esprit Basic Research Action Working Group No. 3166 ASMICS, the CNRS and the Academy of Finland     

Grid-Computing

Grid-Computing, ein Mitte der 90er-Jahre eingeführter Begriff [1,2], bezeichnet eine Architektur für verteilte Systeme, die auf dem World Wide Web aufbaut und die Web-Vision erweitert. Mit dem Grid-Computing werden die Ressourcen einer Gemeinschaft, einer so genannten virtuellen Organisation, integriert. Die Hoffnung ist, dass hierdurch rechen- und/oder datenintensiven Aufgaben, die eine einzelne Organisation nicht lösen kann, handhabbar werden. Ein Grid bezeichnet eine nach dem Grid-Computing-Ansatz aufgebaute Rechner-, Netzwerk- und Software-Infrastruktur zur Teilung von Ressourcen mit dem Ziel, die Aufgaben einer virtuellen Organisation zu erledigen. * Vorschläge an Prof.Dr. Frank Puppe <puppe@informatik.uni-wuerzburg.de> oder Dieter Steinbauer <dieter.steinbauer@schufa.de>Alle Aktuellen Schlagwörter seit 1988 finden Sie unter: www.ai-wuerzburg.de/as     

Utilizing deontic operators in information systems specification

One major task in requirements specification is to capture the rules relevant to the problem at hand. Declarative, rule-based approaches have been suggested by many researchers in the field. However, when it comes to modeling large systems of rules, not only for the behavior of the computer system but also for the organizational environment surrounding it, current approaches have problems with limited expressiveness, flexibility, and poor comprehensibility. Hence, rule-based approaches may benefit from improvements in two directions: (1) improvement of the rule languages themselves and (2) better integration with other, complementary modeling approaches.In this article, both issues are addressed in an integrated manner. The proposal is presented in the context of the Tempora project on rule-based information systems development, but has also been integrated with PPP. Tempora has provided a rule language based on an executable temporal logic working on top of a temporal database. The rule language is integrated with static (ER-like) and dynamic (SA/RT-like) modeling approaches. In the current proposal, the integration with complementary modeling approaches is extended by including organization modeling (actors, roles), and the expressiveness of the rule language is increased by introducing deontic operators and rule hierarchies. The main contribution of the article is not seen as any one of the above-mentioned extensions, but as the resulting comprehensive modeling support. The approach is illustrated by examples taken from an industrial case study done in connection with Tempora.C. List of Symbols Subset of set - Not subset of set - Element of set - Not element of set - Equivalent to - Not equivalent to - ¬ Negation - Logical and - Logical or - Implication - Sometime in past - Sometime in future - Always in past - Always in future - Just before - Just after - u Until - s Since - Trigger - Condition - _s State condition - Consequence - _a Action - _s State - Role - Actor - ¬ - General deontic operator - O Obligatory - R Recommended - P Permitted - D Discouraged - F Forbidden - (/–) General rule - t _R Real time - t _M Model time     

A Typology of Translation Problems for Eurotra Translation Machines

This paper presents a detailed study of Eurotra Machine Translation engines, namely the mainstream Eurotra software known as the E-Framework, and two unofficial spin-offs – the C,A,T and Relaxed Compositionality translator notations – with regard to how these systems handle hard cases, and in particular their ability to handle combinations of such problems. In the C,A,T translator notation, some cases of complex transfer are wild, meaning roughly that they interact badly when presented with other complex cases in the same sentence. The effect of this is that each combination of a wild case and another complex case needs ad hoc treatment. The E-Framework is the same as the C,A,T notation in this respect. In general, the E-Framework is equivalent to the C,A,T notation for the task of transfer. The Relaxed Compositionality translator notation is able to handle each wild case (bar one exception) with a single rule even where it appears in the same sentence as other complex cases.     

Fodorian semantics,pathologies, and “Block's Problem”

In two recent books, Jerry Fodor has developed a set of sufficient conditions for an object X to non-naturally and non-derivatively mean X. In an earlier paper we presented three reasons for thinking Fodor's theory to be inadequate. One of these problems we have dubbed the Pathologies Problem. In response to queries concerning the relationship between the Pathologies Problem and what Fodor calls Block's Problem, we argue that, while Block's Problem does not threatenFodor's view, the Pathologies Problem does.We would like to thank Ray Elugardo, Pat Manfredi, and Donna Summerfield for helpful comments on an earlier paper on Fodorian Semantics, X means X: Semantics Fodor-Style. We would especially like to thank Ned Block for extended e-mail conversations about Block's Problem. Block agrees that his problem is not the same as our pathologies problem. Contrary to what we say here, he still maintains that his objection can ultimately be made to work to defeat Fodor's theory of meaning. His elaboration of Block's Problem is different than the one we present here. Versions of a related paper were presented at the 1991 Annual Meeting of the Southern Society for Philosophy and Psychology as well as the Canadian Society for History and Philosophy of Science.     

The dynamic clusters method in nonhierarchical clustering

Given a finite setE R ⁿ, the problem is to find clusters (or subsets of similar points inE) and at the same time to find the most typical elements of this set. An original mathematical formulation is given to the problem. The proposed algorithm operates on groups of points, called samplings (samplings may be called multiple centers or cores); these samplings adapt and evolve into interesting clusters. Compared with other clustering algorithms, this algorithm requires less machine time and storage. We provide some propositions about nonprobabilistic convergence and a sufficient condition which ensures the decrease of the criterion. Some computational experiments are presented.     

Soft computing in engineering design: a hybrid dual cross-mapping neural network model

Contemporary design process requires the development of a new computational intelligence or soft computing methodology that involves intelligence integration and hybrid intelligent systems for design, analysis and evaluation, and optimization. This paper first presents a discussion of the need to incorporate intelligence into an automated design process and the various constraints that designers face when embarking on industrial design projects. Then, it presents the design problem as optimizing the design output against constraints and the use of soft computing and hybrid intelligent systems techniques. In this paper, a soft-computing-integrated intelligent design framework is developed. A hybrid dual cross-mapping neural network (HDCMNN) model is proposed using the hybrid soft computing technique based on cross-mapping between a back-propagation network (BPNN) and a recurrent Hopfield network (HNN) for supporting modeling, analysis and evaluation, and optimization tasks in the design process. The two networks perform different but complementary tasks—the BPNN decides if the design problem is a type 0 (rational) or type 1 (non-rational) problem, and the output layer weights are then used as the energy function for the HNN. The BPNN is used for representing design patterns, training classification boundaries, and outputting network weight values to the HNN, and then the HNN uses the calculated network weight values to evaluate and modify or re-design the design patterns. The developed system provides a unified soft-computing-integrated intelligent design framework with both symbolic and computational intelligence. The system has self-modifying and self-learning functions. Within the system, only one network training is needed for accomplishing the evaluation, rectification/modification, and optimization tasks in the design process. Finally, two case studies are provided to illustrate and validate the developed model and system.     

Regions-of-Interest and Spatial Layout for Content-Based Image Retrieval

To date most content-based image retrieval (CBIR) techniques rely on global attributes such as color or texture histograms which tend to ignore the spatial composition of the image. In this paper, we present an alternative image retrieval system based on the principle that it is the user who is most qualified to specify the query content and not the computer. With our system, the user can select multiple regions-of-interest and can specify the relevance of their spatial layout in the retrieval process. We also derive similarity bounds on histogram distances for pruning the database search. This experimental system was found to be superior to global indexing techniques as measured by statistical sampling of multiple users' satisfaction ratings.     

A Philosophical Approach to the Concept of Data Model: Is a Data Model, in Fact, a Model?

The design of the database is crucial to the process of designing almost any Information System (IS) and involves two clearly identifiable key concepts: schema and data model, the latter allowing us to define the former. Nevertheless, the term model is commonly applied indistinctly to both, the confusion arising from the fact that in Software Engineering (SE), unlike in formal or empirical sciences, the notion of model has a double meaning of which we are not always aware. If we take our idea of model directly from empirical sciences, then the schema of a database would actually be a model, whereas the data model would be a set of tools allowing us to define such a schema.The present paper discusses the meaning of model in the area of Software Engineering from a philosophical point of view, an important topic for the confusion arising directly affects other debates where model is a key concept. We would also suggest that the need for a philosophical discussion on the concept of data model is a further argument in favour of institutionalizing a new area of knowledge, which could be called: Philosophy of Engineering.     

More Church–Rosser Proofs

The proofs of the Church–Rosser theorems for , , and reduction in untyped -calculus are formalized in Isabelle/HOL, an implementation of Higher Order Logic in the generic theorem prover Isabelle. For -reduction, both the standard proof and Takahashi's are given and compared. All proofs are based on a general theory of commutating relations that supports an almost geometric style of reasoning about confluence diagrams.