Browsing by Author "Lin, Bao-Shuh P."

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An Empirical Study on Data Retrievability in Decentralized Erasure Code Based Distributed Storage Systems
(2013)
Lin, Hsiao-Ying
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Tung, Li-Ping
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Lin, Bao-Shuh P.
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資訊工程學系
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Department of Computer Science
Erasure codes are applied in distributed storage systems to provide data robustness against server failures by storing data redundancy among many storage servers. A (n, k) erasure code encodes a data object, which is represented as k elements, into a codeword of n elements such that any k out of these n codeword elements can recover the data object back. Decentralized erasure codes are proposed for distributed storage systems without a central authority. The characteristic of decentralization makes resulting storage systems more scalable and suitable for loosely-organized networking environments. However, different from conventional erasure codes, decentralized erasure codes trade some probability of a successful data retrieval for decentralization. Although theoretical lower bounds on the probability are overwhelming from a theoretical aspect, it is essential to know what the data retrievability is in real applications from a practical aspect. We focus on decentralized erasure code based storage systems and investigate data retrievability from both theoretical and practical aspects. We conduct simulation for random processes of storage systems to evaluate data retrievability. Then we compare simulation results and analytical values from theoretical bounds. By our comparison, we find that data retrievability is underestimated by those bounds. Data retrievability is over 99% in most cases in our simulations, where the order of the used finite field is an 8-bit prime. Data retrievability can be enlarged by using a larger finite field. We believe that data retrievability of decentralized erasure code based storage systems is acceptable for real applications.
COMPUTER-ASSISTED SELF-TRAINING SYSTEM FOR SPORTS EXERCISE USING KINECTS
(2013)
Chen, Hua-Tsung
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He, Yu-Zhen
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Chou, Chien-Li
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Lee, Suh-Yin
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Lin, Bao-Shuh P.
Self-training plays an important role in sports exercise. However, if not under the instruction of a coach, improper training postures can cause serious harm to muscles and ligaments of the body. Hence, the development of computer-assisted self-training systems for sports exercise is a recently emerging research topic. In this paper, we propose a Yoga self-training system, entitled YogaST, which aims at instructing the user/practitioner to perform the asana (Yoga posture) correctly and preventing injury caused by improper postures. Involving professional Yoga training knowledge, YogaST analyzes the practitioner's posture from both front and side views using two Kinects with perpendicular viewing directions and assists him/her in rectifying bad postures. The contour, skeleton, and feature axes of the human body are extracted as posture representation. Then, YogaST analyzes the practitioner's posture and presents visualized instruction for posture rectification so that the practitioner can easily understand how to adjust his/her posture.
Energy-efficient network selection with mobility pattern awareness in an integrated WiMAX and WiFi network
(2010-02-01)
Yang, Wen-Hsin
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Wang, You-Chiun
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Tseng, Yu-Chee
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Lin, Bao-Shuh P.
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資訊工程學系
To provide wireless Internet access, WiFi networks have been deployed in many regions such as buildings and campuses. However, WiFi networks are still insufficient to support ubiquitous wireless service due to their narrow coverage. One possibility to resolve this deficiency is to integrate WiFi networks with the wide-range WiMAX networks. Under such an integrated WiMAX and WiFi network, flow to conduct energy-efficient handovers is a critical issue. In this paper, we propose a handover scheme with geographic mobility awareness (HGMA), which considers the historical handover patterns of mobile devices. HGMA can conserve the energy of handovering devices from three aspects. First, it prevents mobile devices from triggering unnecessary handovers according to their received signal strength and moving speeds. Second, it contains a handover candidate selection method for mobile devices to intelligently select a subset of WiFi access points or WiMAX relay stations to be scanned. Therefore, mobile devices can reduce their network scanning and thus save their energy. Third, HGMA prefers mobile devices staying in their original WiMAX or WiFi networks. This can prevent mobile devices from consuming too much energy on interface switching. In addition, HGMA prefers the low-tier WiFi network over the WiMAX network and guarantees the bandwidth requirements of handovering devices. Simulation results show that HGMA can save about 59-80% of energy consumption of a handover operation, make mobile devices to associate with WiFi networks with 16-62% more probabilities, and increase about 20-61% of QoS satisfaction ratio to handovering devices. Copyright (C) 2009 John Wiley & Sons, Ltd.
HMM-based ball hitting event exploration system for broadcast baseball video
(2012-07-01)
Chen, Hua-Tsung
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Chou, Chien-Li
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Tsai, Wei-Chin
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Lee, Suh-Yin
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Lin, Bao-Shuh P.
With the dramatic growth of fandom population, a considerable amount of research efforts have been devoted to baseball video processing. However, little work focuses on the detailed follow-ups of ball hitting events. This paper proposes a HMM-based ball hitting event exploration system for broadcast baseball video. Utilizing the strictly-defined layout of the baseball field, the proposed system first detects the game-specific spatial patterns in the field, such as the field lines, the bases, the pitch mound, etc. Then, the play region the currently camera-focused region of the baseball field is identified for frame type classification. Since the temporal patterns of presenting the game progress follow a prototypical order, we consider the classified frame types as observation symbols and recognize ball hitting events using HMM. Experiments conducted on broadcast baseball video show encouraging results in frame type classification and ball hitting event recognition. Three practical applications, including highlight clip extraction by user-designated query, storyboard construction, and similar event retrieval, are introduced to address the applicability of our system. (C) 2012 Elsevier Inc. All rights reserved.
On Local Cache Management Strategies for Mobile Augmented Reality
(2014-01-01)
Wu, Chien-Cheng
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Tung, Li-Ping
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Lin, Chih-Yu
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Lin, Bao-Shuh P.
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Tseng, Yu-Chee
Mobile Augmented Reality (MAR) is generally defined as the service that is capable of enhancing the real-world camera views of a smartphone with extra information on top of the screen. Thus, MAR has triggered strong interests in mobile e-commerce, location-based service, etc. However, MAR is usually constrained by the local storage and computing power of the device as well as the latency and bandwidth of the underlying wireless channel. The computation demand is high because a targeted object needs to be compared to lots of images in the database. The communication demand is high because potential objects need to be continuously transmitted to the server and the augmented information needs to be downloaded from the server. This paper investigates the Local Cache Management (LCM) problem to manage the computation and communication work of a mobile device and harmonize the local and remote workloads. We present strategies to pre-fetch higher-priority objects from the server and replace lower-priority objects in the local cache based on temporal and spatial access locality. We verify the effectiveness of our strategies in term of cache hit ratio, response latency, and remote requests via simulations.
Recognizing tactic patterns in broadcast basketball video using player trajectory
(2012-08-01)
Chen, Hua-Tsung
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Chou, Chien-Li
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Fu, Tsung-Sheng
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Lee, Suh-Yin
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Lin, Bao-Shuh P.
"The explosive growth of the sports fandom inspires much research on manifold sports video analyses and applications. The audience, sports fans, and even professionals require more than traditional highlight extraction or semantic summarization. Computer-assisted sports tactic analysis is inevitably in urging demand. Recognizing tactic patterns in broadcast basketball video is a challenging task due to its complicated scenes, varied camera motion, frequently occlusions between players, etc. In basketball games, the action screen means that an offensive player perform a blocking move via standing beside or behind a defender for freeing a teammate to shoot, to receive a pass, or to drive in for scoring. In this paper, we propose a screen-strategy recognition system capable of detecting and classifying screen patterns in basketball video. The proposed system automatically detects the court lines for camera calibration, tracks players, and discriminates the offensive/defensive team. Player trajectories are calibrated to the real-world court model for screen pattern recognition. Our experiments on broadcast basketball videos show promising results. Furthermore, the extracted player trajectories and the recognized screen patterns visualized on a court model indeed assist the coach/players or the fans in comprehending the tactics executed in basketball games informatively and efficiently. (C) 2012 Elsevier Inc. All rights reserved."
Reliable Repair Mechanisms with Low Connection Cost for Code Based Distributed Storage Systems
(2014-01-01)
Lin, Hsiao-Ying
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Tung, Li-Ping
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Lin, Bao-Shuh P.
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資訊工程學系
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Department of Computer Science
Erasure codes are applied in distributed storage systems for fault-tolerance with lower storage overhead than replications. Later, decentralized erasure codes are proposed for decentralized or loosely-organized storage systems. Repair mechanisms aim at maintaining redundancy over time such that stored data are still retrievable. Two recent repair mechanisms, NOOP and COOP, are designed for decentralized erasure code based distributed storage system to minimize connection cost in theoretical manner. We propose a generalized repair framework, which includes NOOP and COOP as two extreme cases. We then investigate trade-off between connection cost and data retrievability from an experimental aspect in our repair framework. Our results show that a reasonable data retrievability is achievable with constant connection cost, which is less than previously analytical values. These results are valuable references for a system manager to build a reliable storage system with low connection cost.
Spatial and Temporal Packet Recovery Schemes for DVB-H Systems through IP-Relay Wireless Networks
(2009)
Yang, Wen-Hsin
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Wang, You-Chiun
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Tseng, Yu-Chee
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Lin, Bao-Shuh P.
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資訊工程學系
The DVB-H standard has been defined to provide digital video broadcast to mobile handheld devices. However, without a request channel, a handheld device may encounter data loss and thus it requires an additional recovery architecture to relieve this problem. In this paper, we follow the DVB-IPDC standard and propose combining a DVB-H system with an IP-relay wireless network. A handheld device losing DVB-H data can thus request the relay network for retransmission. Under this architecture, we identify two critical issues, group packet loss (GPL) and broadcast data handover (BDH). The GPL problem occurs when there are bursty requests for retransmissions of the same data with high spatial and temporal locality, causing network congestion. The BDH problem occurs when these requesting devices move out of their current serving cells. In this paper, we propose a bulk request recovery (BRR) scheme to solve these problems by exploiting spatial and temporal locality of recovery requests. Our scheme can efficiently reduce duplicate requests and schedule retransmissions of lost packets, so both GPL and BDH problems are relieved. Simulations results are also presented to verify the effectiveness of our result.
The Design of Cloud-based 4G/LTE for Mobile Augmented Reality with Smart Mobile Devices
(2013)
Lin, Bao-Shuh P.
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Tsai, Wen-Hsiang
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Wu, C. C.
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Hsu, P. H.
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Huang, J. Y.
The system characteristics of 4G and beyond 4G broadband mobile system (BMS) are high data rate (throughput), low latency (delay), high mobility (speed), and high capacity. The current recognized 4G BMS needs to meet the requirements specified by IMT-Advanced of ITU-T. Those BMSs include 3GPP-LTE/LTE-Advanced and IEEE 802.16e/m (WiMAX 1/WiMAX 2). In the meantime, the smart device (smartphone and tablet) with powerful CPU/GPU, HD digital camera, digital compass, GPS, and various sensors are becoming rapidly popular. In addition, the architecture and capability of cloud computing are getting adopted in various applications and services, a cloud-based 4G/LTE is one example of telecommunications services. With the combination of more deployments of cloud-based BMSs and increasing usages of smart mobile devices, there are many potential appealing applications and services with real-time and/or interactive features can be created. In this article, we explore the technology and applications of mobile augmented reality (MAR) on the cloud-based 4G BMS (TD-LTE) and smart devices environment. The developed smart device-based MAR system (SD-MAR) with the 4G/TD-LTE experimental network testbed is located at MIRC/BML in the campus of National Chiao Tung University. This testbed consists of several brandy dongles/tablets/smartphones (as UE), two NSN TD-LTE base stations (as eNodeB), one core network (as EPC), and cloud-based servers and data center. To study the technology and applications on SD-MAR system, we have integrated research teams/people specialized in the areas of cloud computing, smart device technology, 4G broadband mobile system, computer vision and image processing, gesture recognition, computer graphics and rendering, and system integration. The applications discussed in the article include real-time accurate navigation/tourism for indoor and outdoor, collaborative urban design, and multiuser interactive motion learning system in the mobile environment.
Toward Data Confidentiality via Integrating Hybrid Encryption Schemes and Hadoop Distributed File System
(2012-01-01)
Lin, Hsiao-Ying
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Shen, Shiuan-Tzuo
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Tzeng, Wen-Guey
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Lin, Bao-Shuh P.
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資訊工程學系
With the increasing popularity of cloud computing, Hadoop has become a widely used open source cloud computing framework for large scale data processing. However, few studies have been done to enhance data confidentiality of Hadoop against storage servers. In this paper, we address the data confidentiality issue by integrating hybrid encryption schemes and the Hadoop distributed file system (HDFS). We propose and implement two integrations, HDFS-RSA and HDFS-Pairing, as extensions of HDFS. Experiments are conducted to demonstrate the performance overhead of HDFS-RSA and HDFS-Pairing. Our integrations provide alternatives toward achieving data confidentiality for Hadoop.
Traffic Congestion Classification for Nighttime Surveillance Videos
(2012-01-01)
Chen, Hua-Tsung
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Tsai, Li-Wu
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Gu, Hui-Zhen
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Lee, Suh-Yin
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Lin, Bao-Shuh P.
Traffic surveillance systems have been widely used for traffic monitoring. If the degree of traffic congestion can be evaluated from the surveillance videos immediately, the drivers can choose alternate routes to avoid traffic jam when traffic congestion arises. Compared to daytime surveillance, some tough factors such as poor visibility and higher noise increase the difficulty in video understanding under nighttime environments. In this paper, we propose a framework of traffic congestion classification for nighttime surveillance videos. The framework consists of three steps: the first one is to detect headlights based on three salient headlight features. Second, headlights are grouped into individual vehicles by evaluating their correlations. Third, a virtual detection line is adopted to gather the traffic information for traffic congestion evaluation. Then the traffic congestion is classified into five levels: jam, heavy, medium, mild and low in real-time. We use freeway nighttime surveillance videos to demonstrate the performances on accuracy and computation. Satisfactory experimental results validate the effectiveness of the proposed framework.