6768516
Usage refinement for ER-to-relation design transformations
Database schema refinement based on usage is proposed as a useful next step in a practical database design methodology founded upon entity-relationship (ER) conceptual modeling and transformation to normalized relations. A simple cost model is defined and applied to several examples and a case study, illustrating the important trade-offs among query and update costs, storage requirements, and degree of normalization with its data integrity implications.
24223451
Towards a Semantic e-Community
With the extensive application of the World Wide Web, an important application is community management, many governments have built district-oriented websites to serve the citizens who live, work in the community, named as e-community. The e-community should be up-to-date, personalized and flexible to provide information. Furthermore, they should be embedded with knowledge that can be utilized for content analysis and marketing intelligence and above all with minimal administrative overhead.
2822268
Online Mining in Sensor Networks
Online mining in large sensor networks just starts to attract interest. Finding patterns in such an environment is both compelling and challenging. The goal of this position paper is to understand the challenges and to identify the research problems in online mining for sensor networks. As an initial step, we identify the following three problems to work on: (1) sensor data irregularities detection; (2) sensor data clustering; and (3) sensory attribute correlations discovery. We also outline our preliminary proposal of solutions to these problems.
35922982
Mining Compressed Sequential Patterns
Current sequential pattern mining algorithms often produce a large number of patterns. It is difficult for a user to explore in so many patterns and get a global view of the patterns and the underlying data. In this paper, we examine the problem of how to compress a set of sequential patterns using only K SP-Features(Sequential Pattern Features). A novel similarity measure is proposed for clustering SP-Features and an effective SP-Feature combination method is designed. We also present an efficient algorithm, called CSP( Compressing Sequential Patterns) to mine compressed sequential patterns based on the hierarchical clustering framework. A thorough experimental study with both real and synthetic datasets shows that CSP can compress sequential patterns effectively.
8277660
Web Service Composition Using Markov Decision Processes
This paper discusses a method for dynamic web service composition, which is based on Markov Decision Processes (MDP). It is defined on the base of QoS description and addresses the issue of selecting web services for the purpose of their composition. Web service composition patterns including sequential, conditional, parallel and iterative are modeled in MDP. Two computation algorithms for MDP are introduced and implemented. One is backward recursive iteration and the other is forward iteration, both called Value Iteration. Experiments are conducted to evaluate the performance of MDP methods for service composition. Experimental results show that the methods are efficient. The effect of average failure probability of service invocation on performance is also examined in this paper.
15210585
An XML Based Electronic Medical Record Integration System
In a domain specific information integration system CareHaven, a top-to-down integration strategy is adopted and XML is used as integration media. The main functional components of CareHaven and the disposal of user queries are fully explained in this paper. In the fulfilling of converting XML based query request to SQLs understood by data sources, we decompose the query request to sub requests that are easier to convert. Each sub request is converted with the aid of the mapping data. And the results of all sub requests is combined into one XML documents conformed to a certain DTD.
2295358
Optimal Placement and Selection of Camera Network Nodes for Target Localization
The paper studies the optimal placement of multiple cameras and the selection of the best subset of cameras for single target localization in the framework of sensor networks. The cameras are assumed to be aimed horizontally around a room. To conserve both computation and communication energy, each camera reduces its image to a binary “scan-line” by performing simple background subtraction followed by vertical summing and thresholding, and communicates only the center of the detected foreground object. Assuming noisy camera measurements and an object prior, the minimum mean squared error of the best linear estimate of the object location in 2-D is used as a metric for placement and selection. The placement problem is shown to be equivalent to a classical inverse kinematics robotics problem, which can be solved efficiently using gradient descent techniques. The selection problem on the other hand is a combinatorial optimization problem and finding the optimal solution can be too costly to implement in an energy-constrained wireless camera network. A semi-definite programming approximation for the problem is shown to achieve close to optimal solutions with much lower computational burden. Simulation and experimental results are presented.
6642477
Optimizing state allocation for multicast communications
We propose a new forwarding mechanism for IP multicast based on explicit multicast (Xcast). Compared with traditional IP multicast, our mechanism achieves a more flexible allocation of multicast forwarding states among routers. Previous works only focus on reducing the number of routers which store the forwarding states, ignoring the distribution of forwarding states among routers. The number of forwarding states stored in each router may be unbalanced. We formulate the assignment of the routers with forwarding states as two optimization problems. The first one is to minimize the number of routers with the forwarding states in each multicast tree. The second one is to minimize the maximum number of forwarding states stored in a router. We design several algorithms for both problems. We prove that our algorithms can find the optimal solution to the first problem. By simulation, we also show that our algorithms perform well in the second problem. Moreover, we prove that assigning all branching routers as the only routers with the forwarding states is a special case in our mechanism. Due to higher flexibility, we show that our mechanism use fewer forwarding states, and the distribution of forwarding states is more balanced.
7172030
Information-theoretic inequalities for contoured probability distributions
We show that for a special class of probability distributions that we call contoured distributions, information-theoretic invariants and inequalities are equivalent to geometric invariants and inequalities of bodies in Euclidean space associated with the distributions. Using this, we obtain characterizations of contoured distributions with extremal Shannon and Renyi entropy. We also obtain a new reverse information-theoretic inequality for contoured distributions.
1017528
Parametric interpolator versus linear interpolator for precision CNC machining
Abstract The paper presents a comparative study of linear and parametric interpolators used for command generation during CNC machining. For many decades, linear interpolators have been used in NC machines for command generation. Recently, a parametric interpolator has been developed that is designed for command generation for parametric curves (or surfaces). Two algorithms for the online implementation of this parametric interpolator are introduced. The comparison is mainly based on memory size, feedrate fluctuation and CPU time. Other considerations include tracking errors and jerk magnitude. Results show that the parametric interpolator is favourable in the machining of free-form geometry in terms of high speed and tight tolerancing.
28045056
Orderings on Graphs and Game Coloring Number
Many graph theoretic algorithms rely on an initial ordering of the vertices of the graph which has some special properties. We discuss new ways to measure the quality of such orders, give methods for constructing high quality orders, and provide applications for these orders. While our main motivation is the study of game chromatic number, there have been other applications of these ideas and we expect there will be more.