Weighted Pushdown Systems with Indexed Weight Domains

The reachability analysis of weighted pushdown systems is a very powerful technique in verification and analysis of recursive programs. Each transition rule of a weighted pushdown system is associated with an element of a bounded semiring representing the weight of the rule. However, we have realized that the restriction of the boundedness is too strict and the formulation of weighted pushdown systems is not general enough for some applications. To generalize weighted pushdown systems, we first introduce the notion of stack signatures that summarize the effect of a computation of a pushdown system and formulate pushdown systems as automata over the monoid of stack signatures. We then generalize weighted pushdown systems by introducing semirings indexed by the monoid and weaken the boundedness to local boundedness

Typed Closure Conversion

Closure conversion is a program transformation used by compilers to separate code from data. Previous accounts of closure conversion use only untyped target languages. Recent studies show that translating to typed target languages is a useful methodology for building compilers, because a compiler can use the types to implement efficient data representations, calling conventions, and tag-free garbage collection. Furthermore, type-based translations facilitate security and debugging through automatic type checking, as well as correctness arguments through the method of logical relations. We present closure conversion as a type-directed, and type preserving translation for both the simply-typed and the polymorphic λ--calculus. Our translations are based on a simple "closures as objects" principle: higher-order functions are viewed as objects consisting of a single method (the code) and a single instance variable (the environment). In the simply-typed case, the Pierce-Turner model of object typing where objects are packages of existential type suffices. In the polymorphic case, more careful tracking of type sharing is required. We exploit a variant of the Harper-Lillibridge "translucent type" formalism to characterize the types of polymorphic closures.Engineering and Applied Science

Composite THz materials using aligned metallic and semiconductor microwires, experiments and interpretation

We report fabrication method and THz characterization of composite films containing either aligned metallic (tin alloy) microwires or chalcogenide As2Se3 microwires. The microwire arrays are made by stack-and-draw fiber fabrication technique using multi-step co-drawing of low-melting-temperature metals or semiconductor glasses together with polymers. Fibers are then stacked together and pressed into composite films. Transmission through metamaterial films is studied in the whole THz range (0.1-20 THz) using a combination of FTIR and TDS. Metal containing metamaterials are found to have strong polarizing properties, while semiconductor containing materials are polarization independent and could have a designable high refractive index. Using the transfer matrix theory, we show how to retrieve the complex polarization dependent refractive index of the composite films. We then detail the selfconsistent algorithm for retrieving the optical properties of the metal alloy used in the fabrication of the metamaterial layers by using an effective medium approximation. Finally, we study challenges in fabrication of metamaterials with sub-micrometer metallic wires by repeated stack-and-draw process by comparing samples made using 2, 3 and 4 consecutive drawings. When using metallic alloys we observe phase separation effects and nano-grids formation on small metallic wires

Root and Epistemic must

application/pdf女子大文学. 外国文学篇. 1985, 37, p.37-82departmental bulletin pape

Trends and Implications: The Use of Facebook in the Professional World

The recent trend of connectivity through the Internet has served as a spark for the social media era, resulting in a number of social websites such as Xanga (social blogging site),MySpace, Facebook, Twitter, LinkedIn, and many others. Facebook specifically has become an everyday norm in the lives of most young adults. With the societal shift towards a digitally orientated lifestyle, there is an increased interaction between friends, family, and non-acquaintances via social networking sites like Facebook. As a result, the manner in which users portray themselves online becomes influential for new friends viewing their pages. Similarly, professional companies are now utilizing Facebook for marketing, promotions, and even recruiting. This becomes an issue, then, for young adults looking to launch their careers and are unaware of the way in which companies utilize Facebook. The purpose of this study was to identify how companies use Facebook and whether or not there is a “knowledge gap” between young adults and professionals. Upon learning if and how companies use Facebook, young adults can be informed on how to present themselves online so as to balance their social and professional online image. The results of the study identified a shifting trend towards companies using Facebook in the near future; as social networking merges together with professional networking, it becomes increasingly important to adopt a long-termed mindset. Cautionary tactics are recommended, such as adjusting privacy settings and removing inappropriate images

Some Observations on the Anaphoric Functions of One

application/pdf女子大文学. 外国文学編　内田郁雄教授定年退職記念号. 1982, 34, p.59-93departmental bulletin pape

Deterring Nuclear Attacks on Japan: An Examination of the U.S.-Japan Relationship and Nuclear Modernization

This paper evaluates the effectiveness of the U.S. nuclear weapons arsenal in covering security commitments with its foreign allies, particularly Japan. The U.S. has promised to defend allies all over the world with nuclear forces, and consequently has been forced into a delicate and precarious position. President Barack Obama wants to reach nuclear zero, which would make the world safe from nuclear destruction in the future; yet he also wants to provide security for allied nations in the present, using the very weapons he has marked for destruction. And he is facing an aging Cold War-era nuclear arsenal that needs serious repairs and upgrades in order to remain a credible and capable deterrent. This paper argues that while the U.S nuclear posture up to this point has been satisfactory enough to prevent panic and ensure protection of Japan, the evolving nuclear posture from this point onward will strengthen the credibility of existing security commitments, deter potential attackers, and give Japan the confidence to become a more coordinated partner in the relationship. Components of the paper include the evolution of U.S. nuclear strategy and deterrence, the three historical occurrences of tensions between the U.S. and Japan over nuclear issues, and the current concerns and actions in the alliance today