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排序方式: 共有1609条查询结果,搜索用时 10 毫秒
1.
Dynamic complexity investigates the required effort to maintain knowledge about a property of a structure under changing operations.
This article introduces a refined notion of dynamic problems which takes the initial structure into account. It develops the
basic structural complexity notions accordingly. It also shows that the dynamic version of the LOGCFL-complete problem D2LREACH(acyclic) can be maintained with first-order updates. 相似文献
2.
Das Autobahnmautgesetz zeichnet sich durch eine strenge Zweckbindung für die Mautdaten aus. Diese dürfen ausschlie?lich für
die Zwecke des Mautgesetzes erhoben und verarbeitet werden. Diese Vorgabe hat das LG Magdeburg in einem Beschluss richtungsweisend
auch für die Verbindungsdaten der GSM-Kommunikation best?tigt. 相似文献
3.
Reliability aspects of microsensors and micromechatronic actuators for automotive applications 总被引:1,自引:0,他引:1
In modern cars microsensors and micromechatronic actuators play an essential and still increasingly important role as the interface between the vehicle with its complex functions of motor management, chassis systems, safety as well as comfort and convenience on the one hand and the respective electronic control units on the other hand. They have to fulfill their task in a harsh environment over the entire lifetime of an automobile. Therefore reliability aspects have moved more and more into the focus of engineering and research activities in microsystem technology. A methodical procedure is described that allows reliability issues to be approached efficiently. The implementation of the methodology is illustrated with real-life examples of reliability aspects of hot film mass air flow sensors, inertial sensors as well as piezoelectric actuators. 相似文献
4.
5.
Benedikt Ley Corinna Ogonowski Jan Hess Tim Reichling Lin Wan Volker Wulf 《Behaviour & Information Technology》2014,33(8):815-828
Technological infrastructure at home is changing continuously and is becoming increasingly interconnected. Media devices, including the TV set, provide access to the Internet and offer manifold opportunities to consume media on demand. Additionally, personal devices, such as smartphones, also enable flexible consumption and sharing of media. Questions about how these technologies change the user's media usage and how these changes affect the social structure of a household, however, remain largely unanswered. In order to gain insight into the adoption of new technologies into daily routines, we explored these changes in respect of people's media usage in a qualitative long-term Living Lab study. We will present findings regarding personal routines, flexible integration of new devices into existing practices, influences on households as social systems and related issues in device access and collective use. We will highlight potentials and conflicts regarding device shifts and roles; restrictions in device access; social influences in the living room; and individual changes in media consumption. 相似文献
6.
Rafael Prikladnicki Alexander Boden Gabriela Avram Cleidson R. B. de Souza Volker Wulf 《Empirical Software Engineering》2014,19(4):822-856
Global Software Engineering has become a standard in today’s software industry. Research in distributed software development poses severe challenges that are due to the spatial and temporal distribution of the actors, as well as to language, intercultural and organizational aspects. These challenges occur in addition to “traditional” challenges of the domain itself in large-scale software projects, like coordination and communication issues, requirements volatily, lack of domain knowledge, among others. While several authors have reported empirical studies of global software development projects, the methodological difficulties and challenges of this type of studies have not been sufficiently discussed. In this paper, we share our experiences of collecting and analysing qualitative data in the context of Global Software Engineering projects. We discuss strategies for gaining access to field sites, building trust and documenting distributed and complex work practices in the context of several research projects we have conducted in the past 9 years. The experiences described in this paper illustrate the need to deal with fundamental problems, such as understanding local languages and different cultures, observing synchronous interaction, or dealing with barriers imposed by political conflicts between the sites. Based on our findings, we discuss some practical implications and strategies that can be used by other researchers and provide some recommendations for future research in methodological aspects of Global Software Engineering. 相似文献
7.
Alexander Jones Volker Thoma 《International journal of human-computer interaction》2013,29(20):1914-1935
ABSTRACTAgile and User-centered design processes have been reported to frequently putting contradictory demands on people working within these methodological frameworks. The current research addresses this point by focussing on the crucial relationship between software developer and designer. An online survey, a contextual inquiry, and a diary study were employed with 107 developers and designers in a large media organization to determine the factors for success in agile development cycles. The results from the survey show that while developers and designers have similar levels of satisfaction with agile processes, there are differences in the factors predicting those ratings. Developers are happier with the wider teamwork but want more access to and close collaboration with designers, while the latters’ concern was the quality of the wider teamwork. Additional contextual inquiries and a diary study with pairs of designers and developers reflected the survey findings that close cooperation (and proximity) was essential for improving communication, reducing inefficiencies, and avoiding suboptimal products being released. However, organizational processes, the setup of the work environment, and managerial traditions meant that this close collaboration and localized decision-making was found difficult to maintain. Results from the survey, the contextual inquiry, and the diary study found six factors for success from collaborations emerged. 相似文献
8.
Automatic Construction and Verification of Isotopy Invariants 总被引:1,自引:0,他引:1
Volker Sorge Andreas Meier Roy McCasland Simon Colton 《Journal of Automated Reasoning》2008,40(2-3):221-243
We extend our previous study of the automatic construction of isomorphic classification theorems for algebraic domains by
considering the isotopy equivalence relation. Isotopism is an important generalisation of isomorphism, and is studied by mathematicians in domains
such as loop theory. This extension was not straightforward, and we had to solve two major technical problems, namely, generating
and verifying isotopy invariants. Concentrating on the domain of loop theory, we have developed three novel techniques for
generating isotopic invariants, by using the notion of universal identities and by using constructions based on subblocks.
In addition, given the complexity of the theorems that verify that a conjunction of the invariants form an isotopy class,
we have developed ways of simplifying the problem of proving these theorems. Our techniques employ an interplay of computer
algebra, model generation, theorem proving, and satisfiability-solving methods. To demonstrate the power of the approach,
we generate isotopic classification theorems for loops of size 6 and 7, which extend the previously known enumeration results.
This work was previously beyond the capabilities of automated reasoning techniques.
The author’s work was supported by EPSRC MathFIT grant GR/S31099. 相似文献
9.
Andreas Ruh Adam-Mwanga Dieckmann Richard Heldele Volker Piotter Robert Ruprecht Christian Munzinger Jürgen Fleischer Jürgen Haußelt 《Microsystem Technologies》2008,14(12):1805-1811
In the field of micro-technology the production of metallic and ceramic micro-components by powder injection molding (PIM)
has become a more and more established fabrication method. But in order to fulfill the demand for more complex-shaped high-precision
micro-components further development work has to be performed. This is especially true if more efficient production routes
for multi-component-micro-assemblies consisting of different materials or sub-components are envisaged. To meet these challenges,
investigations are performed to realize and to establish two primary shape micro-processes. These are two-component micro-injection
molding (2C-MicroPIM) and sinter-joining. The realization of these technologies will lead to a markedly reduction of the efforts
for handling, adjustment, and assembling of metallic and ceramic micro-assemblies. Furthermore, an increased integration level
and functionality can be yielded. For an effective transfer of scientific results to industrial applications the whole process
chain must be considered, from development and construction of the tooling as well as of the components to the quality assurance
and determination of the properties of the assemblies after sintering. These primary shape processes shall enable the mutual
processing of different materials within the fabrication process, so avoiding separate mounting or assembling steps. Additionally
fixed and loose junctions between at least two components shall be realized. The progress in research and development will
be demonstrated especially by the implementation of shaft-to-collar connections between micro-gearwheels and corresponding
shafts. Regarding two-component micro-injection molding, the tool construction for shaft-to-collar connections will be presented
as well as first experimental results on the properties of selected ceramic powders and feedstocks for the special requirements
of the 2C-MicroPIM process. With the assembly step being performed outside the injection molding tool before sinter-joining
different parts and geometries can be combined quite easily. The presented article gives an overview on the concept and on
preliminary testing results for the fabrication of a shaft-to-collar-connection. Additionally, a solution for an automated
assembly of a shaft and a toothed wheel outside the injection molding tool is presented. 相似文献
10.
Kai Schubert Anne Weibert Volker Wulf 《International journal of human-computer studies》2011,69(10):669-678
Located in socially and culturally diverse neighborhoods, we have built a network of intercultural computer clubs, called come_IN. These clubs offer a place to share practices among children and adults of diverse ethnical backgrounds. We show how this initiative ties into the striving for the integration of migrant communities and host society in Germany. In this paper, we analyze how collaborative project work and the use of mobile media and technologies contribute to integration processes in multicultural neighborhoods. Qualitative data gathered from interviews with club participants, participative observation in the computer clubs, as well as the analysis of artifacts created during project work provides the background needed to match local needs and peculiarities with (mobile) technologies. Based on these findings we present two approaches to add to the technological infrastructure: (1) a mesh-network extending the clubs into the neighborhood and (2) a project management tool, which supports projects and stimulates the sharing of ideas among projects. 相似文献