30047573
Self-adaptive Statistics Management for Efficient Query Processing
Consistently good performance required by mission-critical information systems has made it a pressing demand for self-tuning technologies in DBMSs. Automated Statistics management is an important step towards a self-tuning DBMS and plays a key role in improving the quality of execution plans generated by the optimizer, and hence leads to shorter query processing times. In this paper, we present SASM, a framework for Self-Adaptive Statistics Management where, using query feedback information, an appropriate set of histograms is recommended and refined, and through histogram refining and reconstruction, fixed amount of memory is dynamically distributed to histograms which are most useful to the current workload. Extensive experiments showed the effectiveness of our techniques.
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.
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
14012459
MSFSS: A Storage System for Mass Small Files
We designed and implemented MSFSS, a scalable and flexible distributed file system for storage and retrieval of mass small files. MSFSS is a platform built upon the existing commodity file systems. It automatically stores files onto the best-fit commodity file systems according their access patterns. To avoid central bottleneck, it optimizes metadata size, separates metadata operations from file data transfer, and implements batch metadata operations. The system provides data migration, hot file caching, and replication, which are essential for large scale, reliable storage systems. It has successfully been deployed as storage system for our Web application which has about 50 TB of small files. Experimental results show that MSFSS provides high scalability and throughput in file operation services.
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
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.
38698913
A unified fault model and test generation procedure for interconnect opens and bridges
A unified gate-level fault model for interconnect opens and bridges is proposed. Defects are modeled as constrained multiple line stuck-at faults. A novel feature of the proposed fault model is its flexibility to accommodate increasing levels of accuracy. Additionally the model does not require accurate device level circuit models to achieve desired accuracy. Efficient methods for fault simulation and test generation are discussed and experimental results on benchmark circuits and industrial designs are presented. The experimental results presented show that the tests generated using simpler versions of the proposed fault model achieve higher defect coverage than the tests using two currently popular methods to derive high defect coverage tests.
25276326
Web-Based Service Management of Distributed Learning
This paper tries to design structure of Web-Based Service Management of Distributed Learning (WSMDL). The structure integrating IT service and Educational Auxiliary System service flow. Help desk becomes only interface for all levels of users according to their individual demands. Though analysis of service events and user’s feedback in service flow, it also provides the decision-making to improve the quality of Web-based Service Management of Distributed Learning Service Management. The paper also depicts the functions of WSMDL.
15229361
A picosecond TDC architecture for multiphase PLLs
This paper presented a time-to-digital converter (TDC) embedded PLL in 3D silicon-on-insulator (SOI) process. The difficulty of tier-to-tier interconnection modeling in 3D process is very critical. The proposed TDC effectively eliminates the phase mismatches introduced by interconnection between different tiers among multiphase clocks in the 3D process. The large process variation presented in the 3D integrated circuits requires digital compensation techniques to accurately control the timing. The TDC structure presented in this paper replaced the traditional long Vernier delay line and achieved a 2ps timing resolution. A feedback structure is implemented into the TDC to eliminate the influence of the PVT variations on the timing resolution. The multiphase PLL frequency is 3.8GHz in this paper. Simulation results show that the clock jitter was decreased from 5.98ps to 3.58ps with the proposed TDC phase calibration circuit which presents a significant decrease of phase mismatches.
14149219
Multi-agent coordination: a fuzzy logic based approach
In the past decade, the multiagent systems have appeared as a new promising software paradigm. However, its succesful application is subject to the adoption of effective agent coordination techniques. In this paper, we consider a fuzzy logic based approach to agent coordination. Specifically, a bidding based coordination strategy has been proposed to manage the inter-relations among agents. The strategy is developed under the fuzzy logic based task structure model (FSTS) we proposed. Through using the strategy, agents can effectively coordinate their behaviors without consuming so much communication and computation resources.
33123759
Assessment of Color Video Quality Based on Quaternion Singular Value Decomposition
Measurement of visual quality is of fundamental importance for numerous video processing applications. In this paper, we proposed a full-reference color video quality assessment based on quaternion singular value decomposition(QSVD), which takes into account the luminance, chrominance and gradient information of each pixel and treats them as a whole. The algorithm is tested on the video quality experts group (VQEG) Phase I FR-TV test dataset. Experiments show that it has good correlation with perceived video quality.