Lipschitz continuity and the termination of interval methods for global optimization

AbstractIn this paper, it is shown how the Lipschitz continuity of a global optimization problem's objective function influences the termination of a Hansen type method. The results concern applying different termination criteria to a Hansen method and retrieving more information than explicitly supplied by a certain criterion. A similar result for Moore-Skelboe methods arises, as a consequence

Combining over- and under-approximating program analyses for automatic software testing

This dissertation attacks the well-known problem of path-imprecision in static program analysis. Our starting point is an existing static program analysis that over-approximates the execution paths of the analyzed program. We then make this over-approximating program analysis more precise for automatic testing in an object-oriented programming language. We achieve this by combining the over-approximating program analysis with usage-observing and under-approximating analyses. More specifically, we make the following contributions. We present a technique to eliminate language-level unsound bug warnings produced by an execution-path-over-approximating analysis for object-oriented programs that is based on the weakest precondition calculus. Our technique post-processes the results of the over-approximating analysis by solving the produced constraint systems and generating and executing concrete test-cases that satisfy the given constraint systems. Only test-cases that confirm the results of the over-approximating static analysis are presented to the user. This technique has the important side-benefit of making the results of a weakest-precondition based static analysis easier to understand for human consumers. We show examples from our experiments that visually demonstrate the difference between hundreds of complicated constraints and a simple corresponding JUnit test-case. Besides eliminating language-level unsound bug warnings, we present an additional technique that also addresses user-level unsound bug warnings. This technique pre-processes the testee with a dynamic analysis that takes advantage of actual user data. It annotates the testee with the knowledge obtained from this pre-processing step and thereby provides guidance for the over-approximating analysis. We also present an improvement to dynamic invariant detection for object-oriented programming languages. Previous approaches do not take behavioral subtyping into account and therefore may produce inconsistent results, which can throw off automated analyses such as the ones we are performing for bug-finding. Finally, we address the problem of unwanted dependencies between test-cases caused by global state. We present two techniques for efficiently re-initializing global state between test-case executions and discuss their trade-offs. We have implemented the above techniques in the JCrasher, Check 'n' Crash, and DSD-Crasher tools and present initial experience in using them for automated bug finding in real-world Java programs.Ph.D.Committee Chair: Smaragdakis, Yannis; Committee Member: Dwyer, Matthew; Committee Member: Orso, Alessandro; Committee Member: Pande, Santosh; Committee Member: Rugaber, Spence

Die Rolle von Interferon Lambda im Kontext der Fibrose und Infektion der Lunge durch MHV-68

Interferon lambda spielt bei der Pathogenabwehr im menschlichen Körper vor allem in epithelzellreichen Organen eine entscheidende Rolle. Herpesviren werden zu den wichtigen Cofaktoren bei der Pathogenese der idiopathischen Lungenfibrose (IPF) gezählt, weil sie in den Zellen der Lunge verbleiben und durch rezidivierende Reaktivierung einen chronischen Infektstimulus darstellen. Die Funktionen von Interferon lambda hinsichtlich der IPF-Pathogenese im Rahmen der Gammaherpesvirusinfektion (MHV-68) der murinen Lunge soll in dieser Arbeit beleuchtet werden

Replicability Study: Corpora For Understanding Simulink Models & Projects

Background: Empirical studies on widely used model-based development tools such as MATLAB/Simulink are limited despite the tools' importance in various industries. Aims: The aim of this paper is to investigate the reproducibility of previous empirical studies that used Simulink model corpora and to evaluate the generalizability of their results to a newer and larger corpus, including a comparison with proprietary models. Method: The study reviews methodologies and data sources employed in prior Simulink model studies and replicates the previous analysis using SLNET. In addition, we propose a heuristic for determining code-generating Simulink models and assess the open-source models' similarity to proprietary models. Results: Our analysis of SLNET confirms and contradicts earlier findings and highlights its potential as a valuable resource for model-based development research. We found that open-source Simulink models follow good modeling practices and contain models comparable in size and properties to proprietary models. We also collected and distribute 208 git repositories with over 9k commits, facilitating studies on model evolution. Conclusions: The replication study offers actionable insights and lessons learned from the reproduction process, including valuable information on the generalizability of research findings based on earlier open-source corpora to the newer and larger SLNET corpus. The study sheds light on noteworthy attributes of SLNET, which is self-contained and redistributable

Dynamic Test Generation with Static Fields and Initializers

Abstract. Static state is common in object-oriented programs. How-ever, automatic test case generators do not take into account the po-tential interference of static state with a unit under test and may, thus, miss subtle errors. In particular, existing test case generators do not treat static fields as input to the unit under test and do not control the execu-tion of static initializers. We address these issues by presenting a novel technique in automatic test case generation based on static analysis and dynamic symbolic execution. We have applied this technique on a suite of open-source applications and found errors that go undetected by ex-isting test case generators. Our experiments show that this problem is relevant in real code, indicate which kinds of errors existing techniques miss, and demonstrate the effectiveness of our technique.

Speciális túlbecslő függvények alkalmazása az építőmérnöki tervezésben

Investigating engineering problems the enormous necessity of safety has always to be taken into account. The interval analytical approach of design assures that the results - upper bounds - obtained are guaranteed, hence our results are appropriate for building safe structures upon an automatized design. However, the overestimating heuristics are not only useful for the design of reinforced concrete beams, but for all models (e.g. off-line nonlinear regulation) where good stepped overestimators are needed

Collaborative Verification and Testing with Explicit Assumptions

Many mainstream static code checkers make a number of compromises to improve automation, performance, and accuracy. These compromises include not checking certain program properties as well as making implicit, unsound assumptions. Consequently, the results of such static checkers do not provide definite guarantees about program correctness, which makes it unclear which properties remain to be tested. We propose a technique for collaborative verification and testing that makes compromises of static checkers explicit such that they can be compensated for by complementary checkers or testing. Our experiments suggest that our technique finds more errors and proves more properties than static checking alone, testing alone, and combinations that do not explicitly document the compromises made by static checkers. Our technique is also useful to obtain small test suites for partially-verified programs

Globális optimalizálási problémák ellenőrzött pontosságú megoldása mérnöki alkalmazásokban = Solving Global Optimization Problems with Validated Accuracy in Engineering Applications

A projekt keretében eredményesen megvalósult kutatások négy fokozatot foglalnak magukba, melyek témákra bontva a következők voltak: 1. A globális optimalizálási probléma ellenőrzött pontosságú megoldásának lehetőségei, módszerei az intervallum-analízis felhasználásával (22 közlemény). Témák: Intervallum-felosztási eljárások gyorsítása az irányválasztás módosításával; matematikai bizonyítások numerikus eszközökkel; sztochasztikus klaszterező globális optimalizáló eljárások javítása. 2. Új lokális keresők vizsgálata (6 közlemény). Téma: Robusztus deriváltmentes lokális keresők. 3. Globális optimalizálási probléma ellenőrzött megoldása mérnöki alkalmazásokban (37 közlemény). Témák: Káosz vizsgálata a kényszererős inga esetében, ill. Hénon-féle leképezések esetén; vasbetongerendák nyírási vasalásának optimalizálása; optimális beton és vasbeton pontalapok tervezése; optimális rácsos tartók és keretszerkezetek tervezése; szakaszos extraktív desztilláció megvalósíthatósági vizsgálata. 4. Ipari alkalmazások. (14 közlemény). Építőmérnöki alkalmazásokhoz kifejlesztett pontalapok tervezésére szolgáló eljárás segítségével öt tesztprojektben összesen több, mint 100.000 eurós megtakarítást sikerült elérni. A tervezés non-profit alapon történt, a tervezett szerkezetek megvalósultak. | The investigations effectively achieved within the frameworks of the project consist of the following four stages unfolded into subjects: 1 Possibilities and procedures of solving global optimization problems with verified accuracy using interval analysis (22 publications). Subjects: Accelerating interval subdivision methods by changing the subdivision direction selection rule; proving mathematics with numerical tools; improving stochastic clustering global optimization methods. 2 Investigation of new local search methods (6 publications). Subject: Robust derivative-free local search methods. 3 Engineering applications of the global optimization problem's verified solution (37 publications). Subjects: Investigation of chaos in the case of a forced damped pendulum and for the Hénon mapping, resp.; optimization of shear reinforcement of reinforced concrete beams; designing optimal concrete and reinforced concrete single bases; designing optimal trusses and frames; finding limiting flows of batch extractive distillation. 4 Industrial applications (14 publications). With the aid of a procedure developed for designing single bases in civil engineering applications a saving of more than 100,000 Euros in total could be achieved on five test projects. The design was non-profit, the designed structures have been built