17885452
Commutativity-based concurrency control in groupware
Commutativity of operations is often exploited in concurrent systems to attain high levels of concurrency. A commutativity-based concurrency control method, called operational transformation (OT), has been actively researched in groupware over the past 15 years. However, much progress can still be made on more practicable approaches to developing and proving OT algorithms. Several constraints have been proposed previously but they are generally difficult to follow and verify in practice. This paper proposes an alternative approach to address this problem. A new consistency model is defined which greatly simplifies the design and proof of OT algorithms
7412637
EXEC: An Evolvable and eXtensible Environment for Collaboration
This paper presents an evolvable and extensible environment for collaboration (EXEC), which aims to address the long-identified flexibility and reusability issues in collaborative systems. Due to the clean separation between data and control, both user interface components (data) and coordination service components (control) can be reused for developing collaborative applications and be flexibly bound at run time to address the evolutionary needs of collaboration tasks. Additionally, new collaboration tools can be easily prototyped to extend the functionality of the environment
37096144
Operation Propagation in Real-Time Group Editors
Operation propagation refers to the mechanisms and policies used in group editors for the participants to notify each other of their individual editing activities. The timing and granularity of propagation depend on different requirements, such as network bandwidth, session scale, the computational power of the involved sites and the preferences of each user. In this article, we draw on some common design principles in two group editors we have implemented.
17075751
A collaboration specification language
COCA (Collaborative Objects Coordination Architecture) was proposed as a novel means to model and support collaborations over the Internet. Our approach separates coordination policies from user interfaces and the policies are specified in a logic-based language. Over the past year, both the collaboration model and the specification language have been substantially refined and evaluated through our experience in building real-life collaboration systems. This paper presents the design of the specification language and illustrates the main ideas with a few simple design examples. Semantics, implementation, runtime support, and applications are also covered but not as the focus of this paper.
1387834
An Efficient Algorithm for Pattern Discovery in Large Text Databases
17504688
A statistical method for binary classification of images
The classification of documents with sparse text, and video analysis, relies on accurate image classification. We herein present a method for binary classification that accommodates any number of individual classifiers. Each individual classifier is defined by the critical point between its two means, and its relative weighting is inversely proportional to its expected error rate. Using 10 simple image analysis metrics, we distinguish a set of "natural" and "city" scenes, providing a "semantically meaningful" classification. The optimal combination of 5 of these 10 classifiers provides 85.8% accuracy on a small (120 image) feasibility corpus. When this feasibility corpus is then split into half training and half testing images, the mean accuracy of the optimum set of classifiers was 81.7%. Accuracy as high as 90% was obtained for the test set when training percentage was increased. These results demonstrate that an accurate classifier can be constructed from a large pool of simple classifiers through the use of the statistical ("Normal") classification method described herein.
6720899
Mode selection and mode-dependency modeling for power-aware embedded systems
Among the techniques for system-level power management, it is not currently possible to guarantee timing constraints and have a comprehensive system model supporting multiple components at the same time. We propose a new method for modeling and selecting the power modes for the optimal system-power management of embedded systems under timing and power constraints. First, we not only model the modes and the transitions overhead at the component level, but we also capture the application-imposed relationships among the components by introducing a mode dependency graph at the system level. Second, we propose a mode selection technique, which determines when and how to change mode in these components such that the whole system can meet all power and timing constraints. Our constraint-driven approach is a critical feature for exploring power/performance tradeoffs in power-aware embedded systems. We demonstrate the application of our techniques to a low-power sensor and an autonomous rover.
207726898
Quick response policy with Bayesian information updates
Abstract In this paper we investigate the quick response (QR) policy with different Bayesian models. Under QR policy, a retailer can collect market information from the sales of a pre-seasonal product whose demand is closely related to a seasonal product’s demand. This information is then used to update the distribution for the seasonal product’s demand by a Bayesian approach. We study two information update models: one with the revision of an unknown mean, and the other with the revision of both an unknown mean and an unknown variance. The impacts of the information updates under both models are compared and discussed. We also identify the features of the pre-seasonal product which can bring more significant profit improvement. We conclude that an effective QR policy depends on a precise information update model as well as a selection of an appropriate pre-seasonal product as the observation target.
19454602
Asymptotic Strong Duality for Bounded Integer Programming: A Logarithmic-Exponential Dual Formulation
A logarithmic-exponential dual formulation is proposed in this paper for bounded integer programming problems. This new dual formulation possesses an asymptotic strong duality property and guarantees the identification of an optimal solution of the primal problem. These prominent features are achieved by exploring a novel nonlinear Lagrangian function, deriving an asymptotic zero duality gap, investigating the unimodality of the associated dual function and ensuring the primal feasibility of optimal solutions in the dual formulation. One other feature of the logarithmicexponential dual formulation is that no actual dual search is needed when parameters are set above certain threshold-values.