Browsing by Author "Yang, Chao-Tung"

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A dynamic partitioning self-scheduling scheme for parallel loops on heterogeneous clusters
(2006)
Yang, Chao-Tung
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Shih, Wen-Chung
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Tseng, Shian-Shyong
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資訊工程學系
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Department of Computer Science
Loop partitioning on parallel and distributed systems has been an important problem. Furthermore, it becomes more difficult to deal with on the emerging heterogeneous PC cluster environments. In this paper, we propose a performance-based scheme, which dynamically partitions loop iterations according to the performance ratio of cluster nodes. To verify our approach, a heterogeneous cluster is built, and two kinds of application programs are implemented to be executed in this testbed. Experimental results show that our approach performs better than traditional schemes.
A Heuristic Data Distribution Scheme for Data Mining Applications on Grid Environments
(2008-01-01)
Yang, Chao-Tung
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Shih, Wen-Chung
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Tseng, Shian-Shyong
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資訊工程學系
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Department of Computer Science
Effective data distribution techniques can significantly reduce the total execution time of a program on grid computing environments, especially for data mining applications. In this paper, we describe a linear programming formulation for the data distribution problem on grids. Furthermore, a heuristic method, named HDDS (Heuristic Data Distribution Scheme), is proposed to solve this problem. We implement the parallel association rule mining method and conduct the experimentations on our grid testbed. Experimental results showed that data mining programs using our HDDS to distribute data could execute more efficiently than traditional schemes could.
A methodology for retrieving SCORM-compliant teaching materials on grid environments
(2006)
Shih, Wen-Chung
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Yang, Chao-Tung
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Tseng, Shian-Shyong
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資訊工程學系
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Department of Computer Science
This paper proposes a methodology for acquiring the top k highest-ranking SCORM-compliant teaching materials on grid environments, for a given query. Especially, the ranking criterion combines the relevance of the document and the efficiency of transmission. This methodology consists of three steps. First, the ranking function of each Learning Object Repository (LOR) is evaluated. Next, the number of documents to be retrieved from each LOR is decided according to the Ranking Ratio. Finally, the k documents are retrieved from the grid. To verify this approach, a prototype of the retrieval system was built on a grid testbed. Experimental results showed that the proposed approach can retrieve satisfactory teaching materials for users.
A peer-to-peer based framework of InterLibrary cooperation for digital libraries
(2006)
Shih, Wen-Chung
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Yang, Chao-Tung
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Tseng, Shian-Shyong
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Chen, Chun-Jen
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資訊工程學系
Traditionally, InterLibrary Cooperation is an important interaction between libraries. Nevertheless, the emerging digital library architecture has not explicitly supported this requirement. In this paper, we proposed an InterLibrary Cooperation Framework for digital libraries using P2P technology. An application of this framework to Faculty Publication Sharing System was presented. Besides, a reputation model based on data mining is utilized to provide libraries with incentives to join this framework.
A performance-based parallel loop scheduling on grid environments
(2007-09-01)
Shih, Wen-Chung
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Yang, Chao-Tung
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Tseng, Shian-Shyong
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資訊工程學系
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Department of Computer Science
The effectiveness of loop self-scheduling schemes has been shown on traditional multiprocessors in the past and computing clusters in the recent years. However, parallel loop scheduling has not been widely applied to computing grids, which are characterized by heterogeneous resources and dynamic environments. In this paper, a performance-based approach, taking the two characteristics above into consideration, is proposed to schedule parallel loop iterations on grid environments. Furthermore, we use a parameter, SWR, to estimate the proportion of the workload which can be scheduled statically, thus alleviating the effect of irregular workloads. Experimental results on a grid testbed show that the proposed approach can reduce the completion time for applications with regular or irregular workloads. Consequently, we claim that parallel loop scheduling can benefit applications on grid environments.
Decision Support for the Optimization of Provider Staffing for Hospital Emergency Departments with a Queue-Based Approach
(2019-12-01)
Jiang, Fuu-Cheng
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Shih, Cheng-Min
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Wang, Yun-Ming
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Yang, Chao-Tung
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Chiang, Yi-Ju
Deployment or distribution of valuable medical resources has emerged as an increasing challenge to hospital administrators and health policy makers. The hospital emergency department (HED) census and workload can be highly variable. Improvement of emergency services is an important stage in the development of the healthcare system and research on the optimal deployment of medical resources appears to be an important issue for HED long-term management. HED performance, in terms of patient flow and available resources, can be studied using the queue-based approach. The kernel point of this research is to approach the optimal cost on logistics using queuing theory. To model the proposed approach for a qualitative profile, a generic HED system is mapped into the M/M/R/N queue-based model, which assumes an R-server queuing system with Poisson arrivals, exponentially distributed service times and a system capacity of N. A comprehensive quantitative mathematical analysis on the cost pattern was done, while relevant simulations were also conducted to validate the proposed optimization model. The design illustration is presented in this paper to demonstrate the application scenario in a HED platform. Hence, the proposed approach provides a feasibly cost-oriented decision support framework to adapt a HED management requirement.
Dynamic partitioning of loop iterations on heterogeneous PC clusters
(2008-04-01)
Yang, Chao-Tung
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Shih, Wen-Chung
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Tseng, Shian-Shyong
;
資訊工程學系
;
Department of Computer Science
Loop partitioning on parallel and distributed systems has been a critical problem. Furthermore, it becomes more difficult to deal with on the emerging heterogeneous PC cluster environments. In the past, some loop self-scheduling schemes have been proposed to be applicable to heterogeneous cluster environments. In this paper, we propose a performance-based approach, which partitions loop iterations according to the performance ratio of cluster nodes. To verify the proposed approach, a heterogeneous cluster is built, and three types of application programs are implemented to be executed in this testbed. Experimental results show that the proposed approach performs better than traditional schemes.
Interference-Aware Mode Selection for New Arriving Devices in D2D Communications
(2018-01-01)
Hu, Chia-Wei
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Chien, Feng-Tsun
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Yang, Chao-Tung
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Chan, Yu-Wei
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Min, Geyong
In this work, we consider mode selection mechanisms for device-to-device (D2D) communications underlaying a cellular network with multiple existing active D2D pairs. Focusing on the mode selection of the new arrival D2D pair with existing D2D pairs and cellular users, we study the mode selection rules based on the signal-to-interference plus noise ratio (SINR) of the new arrival user and the overall system capacity. For each selection rule, we utilize and discuss pros/cons of two different sets of precoders. In the first set of precoder choice, the block diagonalization (BD) is implemented among cooperating cellular users while zero forcing (ZF) is adopted for the D2D users. In the second set, the maximum signal-to-leakage-and-noise ratio (SLNR) precoder is employed for both cellular users and D2D pairs. The simulation results show that the underlay mode is the best option for the new arrival D2D pair.
Metropolitan-scale grid environment: The implementation and applications of TIGER grid
(2006)
Yang, Chao-Tung
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Han, Tsu-Fen
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Shih, Wen-Chung
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Chiang, Wen-Chung
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Chang, Chih-Hung
Internet computing and Grid technologies promise to change the way we tackle complex problems. Harnessing these new technologies effectively, it will transform scientific disciplines ranging from high-energy physics to life sciences. This paper describes a metropolitan-scale Grid computing platform named TIGER Project (standing for Taichung Integrating Grid Environment and Resource), which basically interconnects universities and high schools\' Grid computing resources and sharing available resources among them, for investigations in system technologies and high performance applications. This novel project shows the viability of implementation of such project in a metropolitan city.
Mode Selection and Spectrum Allocation in Coexisting D2D and Cellular Networks with Cooperative Precoding
(2019-12-02)
Chan, Yu-Wei
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Chien, Feng-Tsun
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Yang, Chao-Tung
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
In this paper, we investigate the mode selection strategies for a new device-to-device (D2D) pair becoming active in a network with a number of existing D2D sensors or users coexisting with cellular users in a D2D-enabled heterogeneous network. Specifically, we propose two selection rules, the signal-to-interference-plus-noise-ratio (SINR)-based and the capacity-based, combined with two sets of different precoding schemes and discuss their impacts on the system under a variety of scenarios. While the cooperative block diagonalization (BD) among the cellular users combined with the zero-forcing (ZF) precoding among D2D users can eliminate interference observed at the new D2D receiving sensor, the maximum signal-to-leakage-and-noise-ratio (SLNR) precoding is often a preferred option due to low-complexity implementations and comparable performance. We note that the two selection rules, the SINR-based and the capacity-based, considered in this paper impact on the system differently, with interesting tradeoff from different perspectives. Finally, we provide insights by simulations into the best selection among the three modes depending on a variety of use cases in the network.
On development of an efficient parallel loop self-scheduling for grid computing environments
(2007-08-01)
Yang, Chao-Tung
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Cheng, Kuan-Wei
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Shih, Wen-Chung
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資訊工程學系
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Department of Computer Science
The approaches to deal with scheduling and load balancing on PC-based cluster systems are famous and well-known. Self-scheduling schemes, which are suitable for parallel loops with independent iterations on cluster computer system, they have been designed in the past. In this paper, we propose a new scheme that can adjust the scheduling parameter dynamically on an extremely heterogeneous PC-based cluster and Grid computing environments in order to improve system performance. A Grid computing environment consists of multiple PC-based clusters is constructed using Globus Toolkit and MPICH-G2 middleware. The experimental results show that our scheduling can result in higher performance than other similar schemes on Grid computing environments. (c) 2007 Elsevier B.V. All rights reserved.
Ontology-based content organization and retrieval for SCORM-compliant teaching materials in data grids
(2009-06-01)
Shih, Wen-Chung
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Yang, Chao-Tung
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Tseng, Shian-Shyong
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資訊工程學系
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Department of Computer Science
With the rapid growth of e-Learning, a tremendous amount of learning content has been developed by numerous providers. Recently, the Sharable Content Object Reference Model (SCORM) has been widely accepted as a standard of e-Learning for users to share and reuse various teaching materials. Data grids, characterized by their goal to manage large-scale dataset, are promising platforms to support sharing of geographically dispersed learning content. However, current data grid standards have not provided complete solutions to content-based information retrieval. To increase the precision of content retrieval oil data grids, our idea is to propose an ontology-based approach to organize and retrieve learning content in geographically dispersed repositories. We designed a layered architecture to enable learning content organization and retrieval on data grids, implemented in a metropolitan-scale grid environment. Experimental results show that the proposed approach can precisely retrieve SCORM-compliant learning content. (c) 2009 Elsevier B.V. All rights reserved.
Performance-based content retrieval for learning object repositories on grid environments
(2006)
Shih, Wen-Chung
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Yang, Chao-Tung
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Chen, Ping-I
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Tseng, Shian-Shyong
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資訊工程學系
The Sharable Content Object Reference Model (SCORM) has become a popular standard for sharing and reusing teaching materials in the field of e-learning. However, efficient retrieval of SCORM-compliant learning objects stored on grid environments is a challenging problem. In this paper, a performance-based approach is proposed to retrieve teaching materials in grid environments. The proposed architecture uses the real-time information gathered by a resource-monitoring tool to estimate the dynamically changing performance of each node, for CPU loading and network bandwidth. In addition, a grid testbed is built to implement the model. Experimental results show that the proposed approach can choose the most appropriate site to reduce the retrieval time.
Performance-based data distribution for data mining applications on grid computing environments
(2010-05-01)
Shih, Wen-Chung
;
Yang, Chao-Tung
;
Tseng, Shian-Shyong
;
資訊工程學系
;
Department of Computer Science
Effective data distribution techniques can significantly reduce the total execution time of a program on grid computing environments, especially for data mining applications. In this paper, we describe a linear programming formulation for the data distribution problem on grids. Furthermore, a heuristic method, named Heuristic Data Distribution Scheme (HDDS), is proposed to solve this problem. We implement two types of data mining applications, Association Rule Mining and Decision Tree Construction, and conduct experiments on grid testbeds. Experimental results show that data mining programs using the proposed HDDS to distribute data could execute more efficiently than traditional schemes could.
Performance-based loop scheduling on grid environments
(2008)
Shih, Wen-Chung
;
Yang, Chao-Tung
;
Tseng, Shian-Shyong
;
資訊工程學系
;
Department of Computer Science
Loop scheduling and load balancing on parallel and distributed systems are critical problems, but it is difficult to cope with these ones, especially on the emerging grid environments. Previous researchers proposed some useful self-scheduling schemes, which were applicable to PC-based cluster and grid computing environments. In this paper, we generalized this concept and proposed a general approach, named PLS (Performance-Based Loop Scheduling). To verify our approach, a grid platform was built, and two application programs, matrix multiplication and Mandelbrot, were implemented with MPI to be executed in this testbed. Experimental results showed that our approach was efficient and robust, in terms of the range of a value.
Performance-based workload distribution on grid environments
(2007)
Shih, Wen-Chung
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Yang, Chao-Tung
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Chen, Tsui-Ting
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Tseng, Shian-Shyong
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資訊工程學系
Imbalanced workload-distribution can significantly degrade performance of grid computing environments. In the past, the theory of divisible load has been widely investigated in static heterogeneous systems. However, it has not been widely applied to grid environments, which are characterized by heterogeneous resources and dynamic environments. In this paper, we propose a performance-based approach to workload distribution for master-slave types of applications on grids. Furthermore, applications with irregular workloads are addressed. We implemented three kinds of applications and conducted experimentations on our grid test-beds. Experimental results show that this approach performs more efficiently than conventional schemes. Consequently, we claim that dynamic workload distribution can benefit applications on grid environments.
Using a Performance-based Skeleton to Implement Divisible Load Applications on Grid Computing Environments
(2009-01-01)
Shih, Wen-Chung
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Yang, Chao-Tung
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Tseng, Shian-Shyong
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資訊工程學系
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Department of Computer Science
Applications with divisible loads have such a rich source of parallelism that their parallelization can significantly reduce their total completion time on grid computing environments. However, it is a challenge for grid users, probably scientists and engineers, to develop their applications which can exploit the computing power of the grid. We propose a performance-based skeleton algorithm for implementing divisible load applications on grids. Following this skeleton, novice grid programmers can easily develop a high performance grid application. To examine the performance of programs developed by this approach, we apply this skeleton to implement three kinds of applications and conduct experiments on our grid test-bed. Experimental results show that programs implemented by this approach run more rapidly than those using conventional scheduling schemes.
Using An Interactive Approach to Finding Right Tutors on P2P Tutoring Grids
(2010-03-01)
Shih, Wen-Chung
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Yang, Chao-Tung
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Tseng, Shian-Shyong
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Chu, Yianshu
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資訊工程學系
The e-Tutors Project supported by MoE, Taiwan, provides remote tutoring service for pupils of rural areas. The preliminary result shows that the learning performance of students has been improved. However, for this service to further assist rural students, the goal of adaptive learning has to be considered in tutor assignment process. Hence, a P2P Tutoring Grid is proposed for the sharing of voluntary tutor resources. In this work, we formulate the tutor finding problem and propose an interactive and iterative heuristic method. The proposed approach consists of two phases: construction phase and search phase. In construction phase, peer information is acquired and managed in a decentralized manner. In search phase, the intention of a query is verified interactively and iteratively to find right tutors. A prototype system has been developed and experiments have been conducted to evaluate the performance of this approach. The experimental results show that the interactive algorithm performs well in peer-to-peer networks with low trust and availability. Also, a survey of satisfaction shows that the proposed method is more user-friendly.
Using taxonomic indexing trees to efficiently retrieve SCORM-compliant documents in e-learning grids
(2008)
Shih, Wen-Chung
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Tseng, Shian-Shyong
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Yang, Chao-Tung
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資訊工程學系
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Department of Computer Science
With the flourishing development of e-Learning, more and more SCORM-compliant teaching materials are developed by institutes and individuals in different sites. In addition, the e-Learning grid is emerging as an infrastructure to enhance traditional e-Learning systems. Therefore, information retrieval schemes supporting SCORM-compliant documents on grid environments are gaining its importance. To minimize the query processing time and content transmission time, our idea is to use a bottom-up approach to reorganize documents in these sites based on their metadata, and to manage these contents in a centralized manner. In this paper, we design an indexing structure named Taxonomic Indexing Trees (TI-trees). A TI-tree is a taxonomic structure and has two novel features: 1) reorganizing documents according to the Classification metadata such that queries by classes can be processed efficiently and 2) indexing dispersedly stored documents in a centralized manner which is suitable for common grid middleware. This approach is composed of a Construction phase and a Search phase. In the former, a local TI-tree is built from each Learning Object Repository. Then, all local TI-trees are merged into a global TI-tree. In the latter, a Grid Portal processes queries and presents results with estimated transmission time to users. Experimental results show that the proposed approach can efficiently retrieve SCORM-compliant documents with good scalability.
Wiki-based rapid prototyping for teaching-material design in e-Learning grids
(2008-11-01)
Shih, Wen-Chung
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Tseng, Shian-Shyong
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Yang, Chao-Tung
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資訊工程學系
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Department of Computer Science
Grid computing environments with abundant resources can support innovative e-Learning applications, and are promising platforms for e-Learning. To support individualized and adaptive learning, teachers are encouraged to develop various teaching materials according to different requirements. However, traditional methodologies for designing teaching materials are time-consuming. To speed up the development process of teaching materials, our idea is to use a rapid prototyping approach which is based on automatic draft generation and Wiki-based revision. This paper presents the approach named WARP (Wiki-based Authoring by Rapid Prototyping), which is composed of five phases: (1) requirement verification, (2) query expansion, (3) teaching-material retrieval, (4) draft generation and (5) Wiki-based revision. A prototype system was implemented in grid environments. The evaluation was conducted using a two-group t-test design. Experimental results indicate that teaching materials can be rapidly generated with the proposed approach. (c) 2007 Elsevier Ltd. All rights reserved.