Ohio State University Commencement

Commencement address given by Marnette Perry, Senior Vice President of The Kroger Company, to the Autumn 2003 graduating class of The Ohio State University, St. John Arena, Columbus, Ohio, December 14, 2003

On Algorithms and Complexity for Sets with Cardinality Constraints

Typestate systems ensure many desirable properties of imperative programs, including initialization of object fields and correct use of stateful library interfaces. Abstract sets with cardinality constraints naturally generalize typestate properties: relationships between the typestates of objects can be expressed as subset and disjointness relations on sets, and elements of sets can be represented as sets of cardinality one. Motivated by these applications, this paper presents new algorithms and new complexity results for constraints on sets and their cardinalities. We study several classes of constraints and demonstrate a trade-off between their expressive power and their complexity. Our first result concerns a quantifier-free fragment of Boolean Algebra with Presburger Arithmetic. We give a nondeterministic polynomial-time algorithm for reducing the satisfiability of sets with symbolic cardinalities to constraints on constant cardinalities, and give a polynomial-space algorithm for the resulting problem. In a quest for more efficient fragments, we identify several subclasses of sets with cardinality constraints whose satisfiability is NP-hard. Finally, we identify a class of constraints that has polynomial-time satisfiability and entailment problems and can serve as a foundation for efficient program analysis.Comment: 20 pages. 12 figure

Energiepreise gefährden den Industriestandort Deutschland

Angesichts steigender Energiepreise wird die Wettbewerbsfähigkeit des Standortes Deutschland in Frage gestellt. Ist der erneute Anstieg der Strompreise nach der Energiemarktliberalisierung eine Folge von Regulierungsdefiziten? Welche Einwirkungsmöglichkeiten wird die Regulierungsbehörde auf den Gas und Strommarkt haben? --

Energiepreise gefährden den Industriestandort Deutschland

Angesichts steigender Energiepreise wird die Wettbewerbsfähigkeit des Standortes Deutschland in Frage gestellt. Ist der erneute Anstieg der Strompreise nach der Energiemarktliberalisierung eine Folge von Regulierungsdefiziten? Welche Einwirkungsmöglichkeiten wird die Regulierungsbehörde auf den Gas und Strommarkt haben

Taming Existence in RDF Querying

We introduce the recursive, rule-based RDF query language RDFLog. RDFLog extends previous RDF query languages by arbitrary quantifier alternation: blank nodes may occur in the scope of all, some, or none of the universal variables of a rule. In addition RDFLog is aware of important RDF features such as the distinction between blank nodes, literals and URIs or the RDFS vocabulary. The semantics of RDFLog is closed (every answer is an RDF graph), but lifts RDF’s restrictions on literal and blank node occurrences for intermediary data. We show how to define a sound and complete operational semantics that can be implemented using existing logic programming techniques. Using RDFLog we classify previous approaches to RDF querying along their support for blank node construction and show equivalence between languages with full quantifier alternation and languages with only ∀∃ rules

A Picture Is Worth a Thousand Words: Code Clone Detection Based on Image Similarity

This paper introduces a new code clone detection technique based on image similarity. The technique captures visual perception of code seen by humans in an IDE by applying syntax highlighting and images conversion on raw source code text. We compared two similarity measures, Jaccard and earth mover’s distance (EMD) for our image-based code clone detection technique. Jaccard similarity offered better detection performance than EMD. The F1 score of our technique on detecting Java clones with pervasive code modifications is comparable to five well-known code clone detectors: CCFinderX, Deckard, iClones, NiCad, and Simian. A Gaussian blur filter is chosen as a normalisation technique for type-2 and type-3 clones. We found that blurring code images before similarity computation resulted in higher precision and recall. The detection performance after including the blur filter increased by 1 to 6 percent. The manual investigation of clone pairs in three software systems revealed that our technique, while it missed some of the true clones, could also detect additional true clone pairs missed by NiCad

Preparation and characterization of particles with small differences in polydispersity

Colloidal particles are widely used both in fundamental research and in materials science. One important parameter influencing the physical properties of colloidal materials is the particle size distribution (polydispersity) of the colloidal particles. Recent work on colloidal crystallization has demonstrated that even subtle changes in polydispersity can have significant effects. In this study we present centrifugation techniques for subtly manipulating the width and the shape of the particle size distribution, for polydispersities less than 10%. We use scanning electron microscopy as well as dynamic and static light scattering to characterize the particle size distributions. We compare the results and highlight the difficulties associated with the determination of accurate particle size distributions