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排序方式: 共有9435条查询结果,搜索用时 15 毫秒
91.
Stephen M. Walls John V. Kucsera Joshua D. Walker Taylor W. Acee Nate K. McVaugh Daniel H. Robinson 《Computers & Education》2010
Instructors in higher education are disseminating instructional content via podcasting, as many rally behind the technology’s potential benefits. Others have expressed concern about the risks of deleterious effects that might accompany the adoption of podcasting, such as lower class attendance. Yet, relatively few studies have investigated students’ perceptions of podcasting for educational purposes, especially in relation to different podcasting forms: repetitive and supplemental. The present study explored students’ readiness and attitudes towards these two forms of podcasting to provide fundamental information for future researchers and educators. The results indicated that students may not be as ready or eager to use podcasting for repetitive or supplemental educational purposes as much as we think they are, but they could be persuaded. 相似文献
92.
We describe a heuristic control policy for a general finite‐horizon stochastic control problem, which can be used when the current process disturbance is not conditionally independent of the previous disturbances, given the current state. At each time step, we approximate the distribution of future disturbances (conditioned on what has been observed) by a product distribution with the same marginals. We then carry out dynamic programming (DP), using this modified future disturbance distribution, to find an optimal policy, and in particular, the optimal current action. We then execute only the optimal current action. At the next step, we update the conditional distribution, and repeat the process, this time with a horizon reduced by one step. (This explains the name ‘shrinking‐horizon dynamic programming’). We explain how the method can be thought of as an extension of model predictive control, and illustrate our method on two variations on a revenue management problem. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
93.
Flynn Castles Stephen M. Morris Damian J. Gardiner Qasim M. Malik Harry J. Coles 《Journal of the Society for Information Display》2010,18(2):128-133
Abstract— The flexoelectro‐optic effect provides a fast‐switching mechanism (0.01–0.1 msec), suitable for use in field‐sequential‐color full‐motion‐video displays. An in‐plane electric field is applied to a short‐pitch chiral nematic liquid crystal aligned in the uniform standing helix (or Grandjean) texture. The switching mechanism is experimentally demonstrated in a single‐pixel test cell, and the display performance is investigated as a function of device parameters. A contrast ratio of 2000:1 is predicted. 相似文献
94.
Current and upcoming demand-response systems provide increasingly detailed power-consumption data to utilities and a growing array of players angling to assist consumers in understanding and managing their energy use. The granularity of this data, as well as new players' entry into the energy market, creates new privacy concerns. The detailed per-household consumption data that advanced metering systems generate reveals information about in-home activities that such players can mine and combine with other readily available information to discover more about occupants' activities. The authors explore the technological aspects of this claim, focusing on the ways in which personally identifying information can be collected and repurposed. Their results show that, even with relatively unsophisticated hardware and data-extraction algorithms, some information about occupant behavior can be estimated with a high degree of accuracy. The authors propose a disclosure metric to aid in quantifying the impact of data collection on in-home privacy and construct an example metric for their experiment. 相似文献
95.
Haiyang Jia Minhong Wang Weijia Ran Stephen J.H. Yang Jian Liao Dickson K.W. Chiu 《Expert systems with applications》2011,38(4):3372-3382
E-learning is emerging as a popular learning approach utilized by many organizations. Despite the ever increasing practices of e-learning in the workplace, most e-learning applications fail to meet learners’ needs or serve organization’s quests for success. Significant gaps exist between organizational interests and individual needs when they come to e-learning, which make e-learning applications less goal-effective. To solve this problem, a performance-oriented approach is presented in this study. Key performance indicators (KPIs) are set up to clarify organizational training needs, and help learners establish rational learning objectives. In addition, ontology is used for constructing formal and machine-understandable conceptualization of the performance-oriented learning environment. Using this approach, a KPI-oriented learning ontology and prototype system have been developed and evaluated to demonstrate the effectiveness of the approach. 相似文献
96.
Gavin Paul Stephen Webb Dikai Liu Gamini Dissanayake 《Robotics and Autonomous Systems》2011,59(7-8):543-554
This paper presents a system for Autonomous eXploration to Build A Map (AXBAM) of an unknown, 3D complex steel bridge structure using a 6 degree-of-freedom anthropomorphic robot manipulator instrumented with a laser range scanner. The proposed algorithm considers the trade-off between the predicted environment information gain available from a sensing viewpoint and the manipulator joint angle changes required to position a sensor at that viewpoint, and then obtains collision-free paths through safe, previously explored regions. Information gathered from multiple viewpoints is fused to achieve a detailed 3D map. Experimental results show that the AXBAM system explores and builds quality maps of complex unknown regions in a consistent and timely manner. 相似文献
97.
Context
Service-Oriented Computing (SOC) is a promising computing paradigm which facilitates the development of adaptive and loosely coupled service-based applications (SBAs). Many of the technical challenges pertaining to the development of SBAs have been addressed, however, there are still outstanding questions relating to the processes required to develop them.Objective
The objective of this study is to systematically identify process models for developing service-based applications (SBAs) and review the processes within them. This will provide a useful starting point for any further research in the area. A secondary objective of the study is to identify process models which facilitate the adaptation of SBAs.Method
In order to achieve this objective a systematic literature review (SLR) of the existing software engineering literature is conducted.Results
During this research 722 studies were identified using a predefined search strategy, this number was narrowed down to 57 studies based on a set of strict inclusion and exclusion criteria. The results are reported both quantitatively in the form of a mapping study, as well as qualitatively in the form of a narrative summary of the key processes identified.Conclusion
There are many process models reported for the development of SBAs varying in detail and maturity, this review has identified and categorised the processes within those process models. The review has also identified and evaluated process models which facilitate the adaptation of SBAs. 相似文献98.
Feehrer John Rotker Paul Shih Milton Gingras Paul Yakutis Peter Phillips Stephen Heath John 《Micro, IEEE》2009,29(4):36-47
CoHub, a coherency hub ASIC, provides a cost-effective way to extend a glueless two-node chip-multithreading system to a four-node system without changes to the processor. The four-node, 256-thread system achieves near-linear scaling of performance with thread count on transaction-processing workloads. Time-to-market pressure, 800-MHz operation, and a six-stage pipeline were among the constraints that shaped CoHub's design. 相似文献
99.
Six different methods to calculate the Strain Index (SI) scores for jobs with multiple forces/tasks were developed. Exposure data of 733 subjects from 12 different worksites were used to calculate these SI scores. Results show that using different SI computation methods could result in different SI scores, hence different risk level classifications. However, some simpler methods generated SI scores were comparable to the more complicated composite SI method. Despite differences in the scores between the six different SI computation methods, Spearman rank-order correlation coefficients of 0.61-0.97 were found between the methods. With some confidence, ergonomic practitioners may use simpler methods, depending on their specificity requirement in job evaluations and available resources. Some SI computation methods may tend to over-estimate job risk levels, while others may tend to under-estimate job risk levels, due to different ways used in obtaining the various SI parameters and computations. 相似文献
100.
Donggang Yu Author Vitae Tuan D. Pham Author Vitae Author Vitae Stephen T.C. Wong Author Vitae 《Pattern recognition》2009,42(4):498-508
Automated analysis of molecular images has increasingly become an important research in computational life science. In this paper some new and efficient algorithms for recognizing and analyzing cell phases of high-content screening are presented. The conceptual frameworks are based on the morphological features of cell nuclei. The useful preprocessing includes: smooth following and linearization; extraction of morphological structural points; shape recognition based morphological structure; issue of touching cells for cell separation and reconstruction. Furthermore, the novel detecting and analyzing strategies of feed-forward and feed-back of cell phases are proposed based on gray feature, cell shape, geometrical features and difference information of corresponding neighbor frames. Experiment results tested the efficiency of the new method. 相似文献