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21.
Chinese TLV-bronze mirrors dating to the Han dynasty (206 B.C.-220 A.D.) were popular objects of everyday life as well as highly esteemed works of art. The decorated back of the mirror characterizes the culture of this period as well as the excellent early Chinese casting techniques.  相似文献   
22.
DuD Recht     

DuD Recht

DuD Recht  相似文献   
23.
In order to address the rapidly increasing load of air traffic operations, innovative algorithms and software systems must be developed for the next generation air traffic control. Extensive verification of such novel algorithms is key for their adoption by industry. Separation assurance algorithms aim at predicting if two aircraft will get closer to each other than a minimum safe distance; if loss of separation is predicted, they also propose a change of course for the aircraft to resolve this potential conflict. In this paper, we report on our work towards developing an advanced testing framework for separation assurance. Our framework supports automated test case generation and testing, and defines test oracles that capture algorithm requirements. We discuss three different approaches to test-case generation, their application to a separation assurance prototype, and their respective strengths and weaknesses. We also present an approach for statistical analysis of the large numbers of test results obtained from our framework.  相似文献   
24.
Virtual worlds, as electronic environments where individuals can interact in a realistic manner in form of avatars, are increasingly used by gamers, consumers and employees. Therefore, they provide opportunities for reinventing business processes. Especially, effective knowledge management (KM) requires the use of appropriate information and communication technology (ICT) as well as social interaction. Emerging virtual worlds enable new ways to support knowledge and knowing processes because these virtual environments consider social aspects that are necessary for knowledge creating and knowledge sharing processes. Thus, collaboration in virtual worlds resembles real‐life activities. In this paper, we shed light on the use of Second Life (SL) as a KM platform in a real‐life setting. To explore the potential and current usage of virtual worlds for knowledge and knowing activities, we conducted a qualitative study at IBM. We interviewed IBM employees belonging to a special workgroup called ‘Web 2.0/virtual worlds’ in order to gain experience in generating and exchanging knowledge by virtually collaborating and interacting. Our results show that virtual worlds – if they are able to overcome problems like platform stability, user interface or security issues – bear the potential to serve as a KM platform. They facilitate global and simultaneous interaction, create a common context for collaboration, combine different tools for communication and enhance knowledge and knowing processes.  相似文献   
25.
As research in Computer-Supported Collaborative Learning (CSCL) expands its understanding of joint knowledge building, new perspectives on how social reality is constructed become necessary. Our research concentrates on the longitudinal or diachronic trajectories of Virtual Math Teams (VMT) at The Math Forum, an online community supporting mathematical inquiry. We investigate how these virtual teams constitute themselves while engaged in building collaborative knowledge. We describe as well, through the lens of positioning theory, the interactional activities that allow participants to situate themselves, others, and their collective knowledge resources over time. Our analysis suggests that positioning work is central to constructing a sustained problem space and illustrates how the configurations of positions and resources that co-participants put forward through interaction might change across a team’s trajectory. These changes constitute and are sensitive to the participants’ evolving reasoning routines and other forms of joint participation uniquely related knowledge building. In addition, we show that the VMT activity system affords participants a level of disciplinary engagement which is partly illustrated by active engagement in positioning work. Finally, we suggest that an interactional approach to roles and participation provides a fruitful framework for researchers, designers, and practitioners interested in understanding and creating engaging CSCL interactions.  相似文献   
26.
In this work a two step approach to efficiently carrying out hyper parameter optimisation, required for building kriging and gradient enhanced kriging metamodels, is presented. The suggested approach makes use of an initial line search along the hyper-diagonal of the design space in order to find a suitable starting point for a subsequent gradient based optimisation algorithm. During the optimisation an upper bound constraint is imposed on the condition number of the correlation matrix in order to keep it from being ill conditioned. Partial derivatives of both the condensed log likelihood function and the condition number are obtained using the adjoint method, the latter has been derived in this work. The approach is tested on a number of analytical examples and comparisons are made to other optimisation approaches. Finally the approach is used to construct metamodels for a finite element model of an aircraft wing box comprising of 126 thickness design variables and is then compared with a sub-set of the other optimisation approaches.  相似文献   
27.
Wireless technologies, under the “Anywhere, Anytime” paradigm, offer users the promise of being always attached to the network. Mobile devices enabled with multiple wireless technologies make possible to maintain seamless connectivity in highly dynamic scenarios such as vehicular networks (VNs), switching from one wireless network to another by using vertical handover techniques (VHO). In this paper we present an overview of VHO techniques, along with the main algorithms, protocols and tools proposed in the literature. In addition we suggest the most appropriate VHO techniques to efficiently communicate in VN environments considering the particular characteristics of this type of networks.  相似文献   
28.
The direct observation of cells over time using time-lapse microscopy can provide deep insights into many important biological processes. Reliable analyses of motility, proliferation, invasive potential or mortality of cells are essential to many studies involving live cell imaging and can aid in biomarker discovery and diagnostic decisions. Given the vast amount of image- and time-series data produced by modern microscopes, automated analysis is a key feature to capitalize the potential of time-lapse imaging devices. To provide fast and reproducible analyses of multiple aspects of cell behaviour, we developed TimeLapseAnalyzer. Apart from general purpose image enhancements and segmentation procedures, this extensible, self-contained, modular cross-platform package provides dedicated modalities for fast and reliable analysis of multi-target cell tracking, scratch wound healing analysis, cell counting and tube formation analysis in high throughput screening of live-cell experiments. TimeLapseAnalyzer is freely available (MATLAB, Open Source) at http://www.informatik.uni-ulm.de/ni/mitarbeiter/HKestler/tla.  相似文献   
29.
Caches impose a major problem for predicting execution times of real-time systems since the cache behavior depends on the history of previous memory references. Too pessimistic assumptions on cache hits can obtain worst-case execution time estimates that are prohibitive for real-time systems. This paper presents a novel approach for deriving a highly accurate analytical cache hit function for C-programs at compile-time based on the assumption that no external cache interference (e.g. process dispatching or DMA activity) occurs. First, a symbolic tracefile of an instrumented C-program is generated based on symbolic evaluation, which is a static technique to determine the dynamic behavior of programs. All memory references of a program are described by symbolic expressions and recurrences and stored in chronological order in the symbolic tracefile. Second, a cache hit function for several cache architectures is computed based on a cache evaluation technique. Our approach goes beyond previous work by precisely modelling program control flow and program unknowns, modelling large classes of cache architectures, and providing very accurate cache hit predictions. Examples for the SPARC architecture are used to illustrate the accuracy and effectiveness of our symbolic cache prediction.  相似文献   
30.
Virtual customer integration and open innovation are considered as appropriate means to improve the success of new product development. However, only when consumers are qualified and motivated to contribute promising ideas and relevant know‐how they are able to add value to a producer's innovation process. In this study, we explore the symmetric and asymmetric impact of various creativity components on consumers' idea generation, concept development, or prototype building abilities as well as interest in co‐creation projects. Our results show that creativity components are of different importance. While some characteristics are needed above certain thresholds to successfully accomplish a certain development task, exceeding those does not necessarily lead to better outputs. Other characteristics improve the creative output only if they exceed specific levels.  相似文献   
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