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991.
This article notes that it is now practical to use the method of enumerationto analyse the performance of estimators and hypothesis tests of fullyparametric binary data models. The general method is presented and thenemployed to investigate the power performance of a common misspecificationtest for the Probit model. The advantages, disadvantages and limitations ofenumeration compared with standard Monte Carlo simulation are thendiscussed. Finally, an example from experimental economics is used todemonstrate that the methodology can also be used in small empirical studies. 相似文献
992.
Nikolaj S. Bjørner Anca Browne Michael A. Colón Bernd Finkbeiner Zohar Manna Henny B. Sipma Tomás E. Uribe 《Formal Methods in System Design》2000,16(3):227-270
We review a number of formal verification techniques supported by STeP, the Stanford Temporal Prover, describing how the tool can be used to verify properties of several versions of the Bakery Mutual exclusion algorithm for mutual exclusion. We verify the classic two-process algorithm and simple variants, as well as an atomic parameterized version. The methods used include deductive verification rules, verification diagrams, automatic invariant generation, and finite-state model checking and abstraction. 相似文献
993.
Formal approaches to the design of interactive systems rely on reasoning about properties of the system at a very high level
of abstraction. Specifications to support such an approach typically provide little scope for reasoning about presentations
and the representation of information in the presentation. In contrast, psychological theories such as distributed cognition place a strong emphasis
on the role of representations, and their perception by the user, in the cognitive process. However, the post-hoc techniques
for the observation and analysis of existing systems which have developed out of the theory do not help us in addressing such
issues at the design stage. Mn this paper we show how a formalisation can be used to investigate the representational aspects
of an interface. Our goal is to provide a framework to help identify and resolve potential problems with the representation
of information, and to support understanding of representational issues in design. We present a model for linking properties
at the abstract and perceptual levels, and illustrate its use in a case study of a ight deck instrument. There is a widespread
consensus that proper tool support is a prerequisite for the adoption of formal techniques, but the use of such tools can
have a profound effect on the process itself. In order to explore this issue, we apply a higher-order logic theorem prover
to the analysis.
Received May 1999 / Accepted in revised form July 2000 相似文献
994.
This paper describes the geometry of imaged curves in two and three views. Multi-view relationships are developed for lines, conics and non-algebraic curves. The new relationships focus on determining the plane of the curve in a projective reconstruction, and in particular using the homography induced by this plane for transfer from one image to another. It is shown that given the fundamental matrix between two views, and images of the curve in each view, then the plane of a conic may be determined up to a two fold ambiguity, but local curvature of a curve uniquely determines the plane. It is then shown that given the trifocal tensor between three views, this plane defines a homography map which may be used to transfer a conic or the curvature from two views to a third. Simple expressions are developed for the plane and homography in each case.A set of algorithms are then described for automatically matching individual line segments and curves between images. The algorithms use both photometric information and the multiple view geometric relationships. For image pairs the homography facilitates the computation of a neighbourhood cross-correlation based matching score for putative line/curve correspondences. For image triplets cross-correlation matching scores are used in conjunction with line/curve transfer based on the trifocal geometry to disambiguate matches. Algorithms are developed for both short and wide baselines. The algorithms are robust to deficiencies in the segment extraction and partial occlusion.Experimental results are given for image pairs and triplets, for varying motions between views, and for different scene types. The methods are applicable to line/curve matching in stereo and trinocular rigs, and as a starting point for line/curve matching through monocular image sequences. 相似文献
995.
Jan Birnstock Tobias Canzler Michael Hofmann Andrea Lux Sven Murano Philipp Wellmann Ansgar Werner 《Journal of the Society for Information Display》2008,16(2):221-229
Abstract— Currently, three issues are identified that decide upon the commercial success of organic light‐emitting diodes (OLEDs), both in display and lighting applications: power efficiency, lifetime, and price competitiveness. PIN OLEDs are widely seen as the preferred way to maximize power efficiency. Here, it is reported that this concept also delivers the world longest lifetimes. For a highly efficient deep‐red PIN OLED, a half‐lifetime of 25,000 hours for a starting brightness of 10,000 cd/m2 and a minimal voltage increase over lifetime is reported. This value corresponds to more than 1 × 106 hours at 1000 cd/m2 using an exponent of n = 1.7, which was measured by driving the OLEDs at different starting luminances. Because there is no initial luminance drop, these PIN OLEDs also exhibit a very high 80% lifetime (>300,000 hours at 1000 cd/m2). New record lifetime values for blue and green will be reported as well. Additionally, further topics that have impact on the production yield and cost such as the newly developed air‐stable organic n‐doping material NDN‐26 and top‐emitting structures will be discussed. 相似文献
996.
With recent advances in the measurement technology for allsky astrophysical imaging, our view of the sky is no longer limited to the tiny visible spectral range over the 2D Celestial sphere. We now can access a third dimension corresponding to a broad electromagnetic spectrum with a wide range of allsky surveys; these surveys span frequency bands including long wavelength radio, microwaves, very short X-rays, and gamma rays. These advances motivate us to study and examine multiwavelength visualization techniques to maximize our capabilities to visualize and exploit these informative image data sets. In this work, we begin with the processing of the data themselves, uniformizing the representations and units of raw data obtained from varied detector sources. Then we apply tools to map, convert, color-code, and format the multiwavelength data in forms useful for applications. We explore different visual representations for displaying the data, including such methods as textured image stacks, the horseshoe representation, and GPU-based volume visualization. A family of visual tools and analysis methods is introduced to explore the data, including interactive data mapping on the graphics processing unit (GPU), the mini-map explorer, and GPU-based interactive feature analysis. 相似文献
997.
998.
Realizing quality improvement through test driven development: results and experiences of four industrial teams 总被引:2,自引:2,他引:0
Nachiappan Nagappan E. Michael Maximilien Thirumalesh Bhat Laurie Williams 《Empirical Software Engineering》2008,13(3):289-302
Test-driven development (TDD) is a software development practice that has been used sporadically for decades. With this practice,
a software engineer cycles minute-by-minute between writing failing unit tests and writing implementation code to pass those
tests. Test-driven development has recently re-emerged as a critical enabling practice of agile software development methodologies.
However, little empirical evidence supports or refutes the utility of this practice in an industrial context. Case studies
were conducted with three development teams at Microsoft and one at IBM that have adopted TDD. The results of the case studies
indicate that the pre-release defect density of the four products decreased between 40% and 90% relative to similar projects
that did not use the TDD practice. Subjectively, the teams experienced a 15–35% increase in initial development time after
adopting TDD.
Nachiappan Nagappan is a researcher in the Software Reliability Research group at Microsoft Research. He received his MS and PhD from North Carolina State University in 2002 and 2005, respectively. His research interests are in software reliability, software measurement and empirical software engineering. Dr. E. Michael Maximilien (aka “max”) is a research staff member at IBM’s Almaden Research Center in San Jose, California. Prior to joining ARC, he spent ten years at IBM’s Research Triangle Park, N.C., in software development and architecture. He led various small- to medium-sized teams, designing and developing enterprise and embedded Java™ software; he is a founding member and contributor to three worldwide Java and UML industry standards. His primary research interests lie in distributed systems and software engineering, especially Web services and APIs, mashups, Web 2.0, SOA (service-oriented architecture), and Agile methods and practices. He can be reached through his Web site (maximilien.org) and blog (blog.maximilien.com). Thirumalesh Bhat is a Development Manager at Microsoft Corporation. He has worked on several versions of Windows and other commercial software systems at Microsoft. He is interested in software reliability, testing, metrics and software processes. Laurie Williams is an associate professor of computer science at North Carolina State University. She teaches software engineering and software reliability and testing. Prior to joining NCSU, she worked at IBM for nine years, including several years as a manager of a software testing department and as a project manager for a large software project. She was one of the founders of the XP Universe conference in 2001, the first US-based conference on agile software development. She is also the lead author of the Pair Programming Illuminated book and a co-editor of the Extreme Programming Perspectives book. 相似文献
Laurie WilliamsEmail: |
Nachiappan Nagappan is a researcher in the Software Reliability Research group at Microsoft Research. He received his MS and PhD from North Carolina State University in 2002 and 2005, respectively. His research interests are in software reliability, software measurement and empirical software engineering. Dr. E. Michael Maximilien (aka “max”) is a research staff member at IBM’s Almaden Research Center in San Jose, California. Prior to joining ARC, he spent ten years at IBM’s Research Triangle Park, N.C., in software development and architecture. He led various small- to medium-sized teams, designing and developing enterprise and embedded Java™ software; he is a founding member and contributor to three worldwide Java and UML industry standards. His primary research interests lie in distributed systems and software engineering, especially Web services and APIs, mashups, Web 2.0, SOA (service-oriented architecture), and Agile methods and practices. He can be reached through his Web site (maximilien.org) and blog (blog.maximilien.com). Thirumalesh Bhat is a Development Manager at Microsoft Corporation. He has worked on several versions of Windows and other commercial software systems at Microsoft. He is interested in software reliability, testing, metrics and software processes. Laurie Williams is an associate professor of computer science at North Carolina State University. She teaches software engineering and software reliability and testing. Prior to joining NCSU, she worked at IBM for nine years, including several years as a manager of a software testing department and as a project manager for a large software project. She was one of the founders of the XP Universe conference in 2001, the first US-based conference on agile software development. She is also the lead author of the Pair Programming Illuminated book and a co-editor of the Extreme Programming Perspectives book. 相似文献
999.
Martin Ebner Michael Kickmeier-Rust Andreas Holzinger 《Universal Access in the Information Society》2008,7(4):199-207
Wikis are a website technology for mass collaborative authoring. Today, wikis are increasingly used for educational purposes.
Basically, the most important asset of wikis is free and easy access for end users: everybody can contribute, comment and
edit—following the principles of Universal access. Consequently, wikis are ideally suited for collaborative learning and a
number of studies reported a great success of wikis in terms of active participation, collaboration, and a rapidly growing
content. However, the wikis success in education was often linked either to direct incentives or even pressure. This paper
strongly argues that this contradicts the original intentions of wikis and, furthermore, weakens the psycho-pedagogical impact.
A study is presented which focuses on investigating the success of wikis in higher education, when students are neither enforced to contribute nor directly rewarded similar to the principles of Wikipedia. Amazingly, the results show that, in total, none of the N = 287 students created new articles or edited existing ones during a whole semester. It is concluded that the use of Wiki-Systems
in educational settings is much more complicated, and it needs more time to develop a kind of “give-and-take” generation. 相似文献
1000.
This paper contextualises, describes and discusses a student project which takes a particular exploratory approach to using
mathematical surface definition as a language and vehicle for co-rational design co-authorship for architecture and engineering.
The project has two authors, one from an architectural and one from an engineering educational background. It investigates
the metaphorical and operational role of mathematics in the design process and outcomes. 相似文献