Information systems based on the World Wide Web increased the impact of concurrent programs. Such increase demands the definition of methods for obtaining safe and efficient implementations of concurrent programs, sin...
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ISBN:
(纸本)1595934804;9781595934802
Information systems based on the World Wide Web increased the impact of concurrent programs. Such increase demands the definition of methods for obtaining safe and efficient implementations of concurrent programs, since the complexity of implementation and tests in concurrent environments is bigger than in sequential environments. This work defined guidelines to restructure object-oriented software in order to modularize concurrency control using aspect-oriented programming. Those guidelines are supported by a concurrency control implementation that guarantees system correctness without redundant concurrency control, both increasing performance and guaranteeing safety. We define abstract aspects that constitute a simple aspect framework that can be reused to implement concurrency control in other applications. The achieved modularization makes the concurrency control easy to evolve and decreases the complexity of other parts of the software, such as business and data management modules, by decoupling concurrency control code from them. Copyright 2007 acm.
Summarizing a set of streaming time series is an important issue that reliably allows information to be monitored and stored in domains such as finance [12], networks [2, 1], etc. To date, most of existing algorithms ...
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Outlyingness is a subjective concept relying on the isolation level of a (set of) record(s). Clustering-based outlier detection is a field that aims to cluster data and to detect outliers depending on their characteri...
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ISBN:
(纸本)9781605581668
Outlyingness is a subjective concept relying on the isolation level of a (set of) record(s). Clustering-based outlier detection is a field that aims to cluster data and to detect outliers depending on their characteristics (small, tight and/or dense clusters might be considered as outliers). Existing methods require a parameter standing for the "level of outlyingness", such as the maximum size or a percentage of small clusters, in order to build the set of outliers. Unfortunately, manually setting this parameter in a streaming environment should not be possible, given the fast time response usually needed. In this paper we propose WOD, a method that separates outliers from clusters thanks to a natural and effective principle. The main advantages of WOD are its ability to automatically adjust to any clustering result and to be parameterless. Copyright 2009 acm.
The proceedings contain 45 papers from the 1st symposium on applied Perception in Graphics and Visualization, APGV 2004. The topics discussed include: recalibration of rotational locomotion in immersive virtual enviro...
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ISBN:
(纸本)1581139144
The proceedings contain 45 papers from the 1st symposium on applied Perception in Graphics and Visualization, APGV 2004. The topics discussed include: recalibration of rotational locomotion in immersive virtual environments;distance perception in real and virtual environments;vision realistic rendering: simulation of the scanned foveal image from wavefront data on human subjects;enhancing perceived depth in images via artistic matting;selective rendering of task related scenes;effective color coding of menu design for movie genres;observations of visual and audio coaching methods in a virtual laparoscopic training environment;selective rendering of task related sceness and causes of depth perception errors.
Developing widely useful mobile computing applications presents difficult challenges. On one hand, mobile users demand intuitive user interfaces, fast response times, and deep relevant content. On the other hand, mobi...
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ISBN:
(纸本)1595934804;9781595934802
Developing widely useful mobile computing applications presents difficult challenges. On one hand, mobile users demand intuitive user interfaces, fast response times, and deep relevant content. On the other hand, mobile devices have limited processing, storage, power, display, and communication resources. Caching frequently accessed data items on the mobile client is an effective technique to improve the system performance in mobile environment. Due to cache size limitation, the choice of cache replacement technique to find a suitable subset of items for eviction from cache becomes important. In this paper, we propose a new cache replacement policy for location dependent data in mobile environment. The proposed policy selects the predicted region based on client's movement and uses it to calculate the weighted data distance of an item. This makes the policy adaptive to client's movement pattern and provides importance to the regions around client's position. This is unlike earlier policies that consider the directional/non-directional data distance only. We call our policy the Weighted Predicted Region based Cache Replacement Policy (WPRRP). Simulation results show that the proposed policy significantly improves the system performance in comparison to previous schemes in terms of cache hit ratio. Copyright 2007 acm.
In this paper, we discuss the results from ethnographic and informance work related to transactions in retail settings as related to the design of interactive ubiquitous computing systems. We find that - for practical...
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The concurrent and non-deterministic nature of the Occam language makes it difficult to program efficiently and to trace the program execution correctly. This paper describes the design and features of Visputer, a too...
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