44697622
MPX: A Multiversion Concurrency Control Protocol for XML Documents
With the rapid popularity of XML, especially in web-base applications, concurrency control of XML documents becomes an important issue. In this paper, we present MPX, a multiversion concurrency control protocol for XML documents, which is designed for synchronizing concurrent queries and modifications of XML documents stored in a native XML databases or XML document repository. Distinguished from other existing protocols, MPX ensures serializability, recoverability and cascadelessness. Furthermore, MPX also guarantees read-only transactions and update transactions will never block each other, which is especially beneficial for XML for queries on XML are much more frequent than updates. Plenty of experiments have also been carried out, confirming that MPX can ensure a better degree of concurrency and less rollbacks.
116588251
On-line evolutionary exponential family mixture
This paper deals with evolutionary clustering, which refers to the problem of clustering data with distribution drifting along time. Starting from a density estimation view to clustering problems, we propose two general on-line frameworks. In the first framework, i.e., historical data dependent (HDD), current model distribution is designed to approximate both current and historical data distributions. In the second framework, i.e., historical model dependent (HMD), current model distribution is designed to approximate both current data distribution and historical model distribution. Both frameworks are based on the general exponential family mixture (EFM) model. As a result, all conventional clustering algorithms based on EFMs can be extended to evolutionary setting under the two frameworks. Empirical results validate the two frameworks.
8340253
UGE4B: An Universal Grid Environment for Bioinformatics Research
Recent years, grid technology has been used widely in the fields of scientific research. In this paper, we present a universal grid environment for bioinformatics research (UGE4B). Although there have been several similar projects successfully constructed in the world, we need to meet some unique requirements from bioinformatics research in China. UGE4B consists of 6 components, including portal, task management, data management, information server, security and computing node. As a national-wide bioinformatics research platform, UGE4B is built through interconnecting multiple sub grids provided by each bioinformatics institutes. Besides provides a universal portal to end users for bioinformatics computing and data accessing, UGE4B also supported some special bioinformatics applications
26669443
Bottom-up discovery of frequent rooted unordered subtrees
In the past decade, XML has emerged as the standard language for information exchanging over the Internet. Due to its tree-structure paradigm, XML is superior for its capability of storing, querying, and manipulating complex data. Therefore, discovering frequent tree patterns over tree-structured data has become an interesting topic for XML data management. In this paper, we propose a tree mining algorithm, named BUXMiner, for finding a special class of frequent trees, called rooted unordered trees, from a tree-structured database. BUXMiner employs an efficient bottom-up approach to enumerate all candidate trees over a compact global tree guide and computes the frequent trees based on the tree guide. In addition to BUXMiner, we also propose a mining approach called BUMXMiner to discover the maximal frequent rooted unordered trees. We compare BUXMiner with previous tree-structure mining algorithms, namely XQPMinerTID and FastXMiner, which were also proposed to discover rooted unordered trees. The experimental results show that our algorithm outperforms XQPMinerTID and FastXMiner in terms of efficiency. The performance results from real-world applications also indicate the usefulness of our proposed tree mining algorithms in a variety of web applications, such as analysis of web page access patterns and mining frequent XML query patterns for caching.
8051159
A Web-based Framework For On-line Collaborative Learning
This paper presents a framework for design of online courses and collaborative learning based on Web technologies. It provides the following features: construction of structured learning materials in a distributed environment; personalization of course contents in the run-time that adapts to the progress of individual students; it can supply relevant Web resources to the students by analyzing the learning history dynamically; students in a group could exchange their learning experiences and discover relevant knowledge via the communication channels provided by the framework. The proposed techniques could be deployed to a variety of online computer-assisted modules to improve the effectiveness of Web-based e-learning
5747087
Efficient Processing of Warping Time Series Join of Motion Capture Data
Discovering non-trivial matching subsequences from two time series is very useful in synthesizing novel time series. This can be applied to applications such as motion synthesis where smooth and natural motion sequences are often required to be generated from existing motion sequences. We first address this problem by defining it as a problem of l-e-join over two time series. Given two time series, the goal of l-e-join is to find those non-trivial matching subsequences by detecting maximal l-connections from the e-matching matrix of the two time series. Given a querying motion sequence, the l-e-join can be applied to retrieve all connectable motion sequences from a database of motion sequences. To support efficient l-e-join of time series, we propose a two-step filter-and-refine algorithm, called Warping Time Series Join (WTSJ) algorithm. The filtering step serves to prune those sparse regions of the e-matching matrix where there are no maximal l-connections without incurring costly computation. The refinement step serves to detect closed l-connections within regions that cannot be pruned by the filtering step. To speed up the computation of e-matching matrix, we propose a block-based time series summarization method, based on which the block-wise e-matching matrix is first computed. Lots of pairwise distance computation of elements can then be avoided by applying the filtering algorithm on the block-wise e-matching matrix.Extensive experiments on l-e-join of motion capture sequences are conducted. The results confirm the efficiency and effectiveness of our proposed algorithm in processing l-e-join of motion capture time series.
15396672
Maintaining System State Information in a Multiagent Environment for Effective Learning
One fundamental issue in multiagent reinforcement learning is how to deal with the limited local knowledge of an agent in order to achieve effective learning. In this paper, we argue that this issue can be more effectively solved if agents are equipped with a consistent global view. We achieve this by requiring agents to follow an interacting protocol. The properties of the protocol are derived and theoretically analyzed. A distributed protocol that satisfies these properties is presented. The experimental evaluations are conducted for a well-known test-case (i.e., pursuit game) in the context of two learning algorithms. The results show that the protocol is effective and the reinforcement learning algorithms using it perform much better. key words: multiagent system, system state, distributed protocol, token ring
6370123
Full integration of subtyping and if-expression
The combination of full subsumption and conditional expression is a challenging problem, because in such a system, a term might not have a type which is a representative of all types of the term. Therefore, the traditional type checking technique fails. Due to such a difficulty, Java typing rule for if-expression uses only a restricted form of subtyping. In this paper, we propose a type system which includes both of the above mentioned features and enjoys decidable type checking. We also show that the system has the subject reduction property. It is expected that this technique could be used to improve the type system of Java with full subsumption.
17839950
Reorganizing global schedules for register allocation
Instruction scheduling is an important compiler technique for exploiting more instruction-level parallelism (ILP) in high-performance microprocessors, and in this paper, we study how to perform global instruction scheduling before register allocation (prepass scheduling) for control-intensive non-numerical applications. As the number of parallel function units in modern microprocessors has increased, compiler writers have increased the size of prepass scheduling regions and the number of speculative operations scheduled. However, if prepass scheduling is not carefully managed, it is easy to create places in a prepass schedule that require more register resources than are architecturally available. We propose an approach that maintains the effectiveness of prepass scheduling in exploiting ILP even with the constraint of a limited number of architectural registers. In particular, we show that the pairing of a greedy prepass scheduler with a code reorganizer performs significantly better than the common approach of using a single register-pressure-sensitive scheduler. Our experimental results show that our non-backtracking, codereorganizing algorithm can eliminate most of the excessive register pressure created by greedy ILP scheduling, and thus improve the overall performance of the globally scheduled regions.
30192317
Modeling and Simulation of Continuous Time-Invariant Systems in Simulation Based Learning Environments
Simulation based learning environments are widely used in elementary and secondary science education. However, a large number of these learning environments are domain-dependent so that they are only useful in some special domains. In this paper, we put forward a new method of simulating continuous time-invariant systems by using frame based knowledge representation and interpretive structural modeling. This method is helpful to realize the separation of knowledge representation and simulation program, and promotes the reusability of a simulation based learning environment.
5453876
Coordinating multi-agents using JavaSpaces
In recent years, multiagent systems have become a new attractive paradigm for developing Internet-based enterprise applications. In this paper, we investigate the agent coordination issue of multiagent systems. We explore the emerging JavaSpace technology for achieving coordination within a multi-level supply chain management environment. JavaSpace is a recent realization of the classic Linda model. The tuple space of the Linda model provides a convenient way for agent communication and coordination. The coordination protocol for the supply chain management system is presented. The protocol is designed based on JavaSpace, and is described using colored Petri nets. We argue that the emerging JavaSpaces technology provides a convenient, yet flexible approach to agent coordination in multiagent system environment.