Browsing by Author "Lee, Wei-Hsun"

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A knowledge based real-time travel time prediction system for urban network
(2009-04-01)
Lee, Wei-Hsun
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Tseng, Shian-Shyong
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Tsai, Sheng-Han
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資訊工程學系
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Department of Computer Science
Many approaches had been proposed for travel time prediction in these decades; most of them focus on the predicting the travel time on freeway or simple arterial network. Travel time prediction for urban network in real time is hard to achieve for several reasons: complexity and path routing problem in urban network, unavailability of real-time sensor data, spatiotemporal data coverage problem, and lacking real-time events consideration. In this paper, we propose a knowledge based real-time travel time prediction model which contains real-time and historical travel time predictors to discover traffic patterns from the raw data of location based services by data mining technique and transform them to travel time prediction rules. Besides, dynamic weight combination of the two predictors by meta-rules is proposed to provide a real-time traffic event response mechanism to enhance the precision of the travel time prediction. (c) 2008 Elsevier Ltd. All rights reserved.
Analysis of the optimum configuration of roadside units and onboard units in dedicated short-range communication systems
(2006-12-01)
Shieh, Wern-Yarng
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Lee, Wei-Hsun
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Tung, Shen-Lung
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Jeng, Bor-Shenn
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Liu, Cheng-Hsin
With the aid of a simple relation, which is analogous to the radar equation, the uplink signal strength received by the receiving module of a roadside unit (RSU) and emitted from the radiation module of an onboard unit (OBU) can be described. Setting the scale of this relation arbitrarily and determining the signal strength threshold from experimental measurements, and combined with the simulation of the radiation and the receiving pattern by cosine(n) function, the relative signal strength emitted from the OBU and received by the RSU can be calculated successfully. From this computed relative signal strength and the threshold, the influence of the RSU and OBU mounting parameters, such as the mounting angles and mounting height, on the available communication region is analyzed. The effect of windshield fading is also considered. With the help of the analysis results, an optimum RSU and OBU mounting configuration can be easily obtained. This method can be used conveniently and successfully for very short wavelengths. This includes visible light, infrared, and even submillimeter-wave ranges. For millimeter-wave and microwave systems, this method can, in some cases, also provide a rudimentary estimation.
Collaborative real-time traffic information generation and sharing framework for the intelligent transportation system
(2010-01-02)
Lee, Wei-Hsun
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Tseng, Shian-Shyong
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Shieh, Wern-Yarng
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資訊工程學系
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Department of Computer Science
Real-time traffic information collection and data fusion is one of the most important tasks in the advanced traffic management system (ATMS), and sharing traffic information to users is an essential part of the advance traveler information system (ATIS) among the intelligent transportation systems (ITS). Traditionally, sensor-based schemes or probing-vehicle based schemes have been used for collecting traffic information, but the coverage, cost, and real-time issues have remained unsolved. In this paper, a wiki-like collaborative real-time traffic information collection, fusion and sharing framework is proposed, which includes user-centric traffic event reacting mechanism, and automatic agent-centric traffic information aggregating scheme. Smart traffic agents (STA) developed for various front-end devices have the location-aware two-way real-time traffic exchange capability, and built-in event-reporting mechanism to allow users to report the real-time traffic events around their locations. In addition to collecting traffic information, the framework also integrates heterogeneous external real-time traffic information data sources and internal historical traffic information database to predict real-time traffic status by knowledge base system technique. (C) 2009 Published by Elsevier Inc.
Design and implementation of electronic toll collection system based on vehicle positioning system techniques
(2008-07-30)
Lee, Wei-Hsun
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Tseng, Shian-Shyong
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Wang, Ching-Hung
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資訊工程學系
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Department of Computer Science
Currently, most electronic toll collection (ETC) systems around the world are implemented by DSRC (dedicated short range communication) technology. However, area wide integrated MLFF (multilane free flow) road charging system is now currently on its development to replace DSRC-based ETC systems. VPS (vehicle positioning system) based ETC system is a category of location based service which tolls vehilces by determining if they move into the charging zone. It is an evolutional technology for area wide integrated road charging solution, which achieves the goal of electronic payment or electronic toll collection by a totally different scheme comparing to traditional DSRC-based technology. In this paper, the design and implementation of VPS-based ETC system is detailedly discussed, and a debit transaction VPS system field test had been practiced in the freeway of Taiwan. (C) 2008 Elsevier B.V. All rights reserved.
Discovering the Radio Signal Coverage Hole and Weak Coverage Area in Mobile Network by Spatiotemporal Data Mining on Location-Based Services
(2010)
Lee, Wei-Hsun
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Tseng, Shian-Shyong
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Wang, Ching-Hung
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Tung, Shen-Lung
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資訊工程學系
Locating the radio signal coverage hole (SCH) and signal weak coverage area (SWCA) in the mobile network and taking appropriate actions to improve network quality are the major tasks for mobile network operators (MNO). A novel approach, Signal Coverage Hole and weak coverage Area DIscovering Model (SCHADIM), is proposed based on spatiotemporal data mining on the raw data collecting from location based service (LBS) to achieve this goal. It reuses the communication raw data in LBS-based applications and transforms it into mobile network communication quality monitoring information by integrating the GIS (geographical information system), road network database and mobile network base station database. By this way, the vehicles in the LBS-based applications can be regarded as the mobile network signal probing vehicles, which provides plentiful information for discovering the SCH/SWCA. Comparing to the traditionalmobile network signal probing vehicle method, which is known as radio site verification (RSV) method, the proposed SCHADIM has the spatiotemporal coverage as well as cost advantages. A mobile network monitoring system, cellular network quality safeguard (CQS), has been implemented based on the proposed model which combines with the domain expert heuristics to provide decision support information for optimizing the mobile network.
RE-MuSiC: a tool for multiple sequence alignment with regular expression constraints
(2007-07-01)
Chung, Yun-Sheng
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Lee, Wei-Hsun
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Tang, Chuan Yi
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Lu, Chin Lung
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生物科技學系
RE-MuSiC is a web-based multiple sequence alignment tool that can incorporate biological knowledge about structure, function, or conserved patterns regarding the sequences of interest. It accepts amino acid or nucleic acid sequences and a set of constraints as inputs. The constraints are pattern descriptions, instead of exact positions of fragments to be aligned together. The output is an alignment where for each pattern (constraint), an occurrence on each sequence can be found aligned together with those on the other sequences, in a manner that the overall alignment is optimized. Its predecessor, MuSiC, has been found useful by researchers since its release in 2004. However, it is noticed in applications that the pattern formulation adopted in MuSiC, namely, plain strings allowing mismatches, is not expressive and flexible enough. The constraint formulation adopted in RE-MuSiC is therefore enhanced to be regular expressions, which is convenient in expressing many biologically significant patterns like those collected in the PROSITE database, or structural consensuses that often involve variable ranges between conserved parts. Experiments demonstrate that RE-MuSiC can be used to help predict important residues and locate phylogenetically conserved structural elements. RE-MuSiC is available on-line at http://140.113.239.131/RE-MUSIC.
Real-Time Driver Assistance Systems via Dual Camera Stereo Vision
(2019-01-01)
Da Sie, Yong
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Tsai, Yi-Cheng
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Lee, Wei-Hsun
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Chou, Chien-Ming
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Chiu, Chi-Yi
This paper presents the practical application for a real-time and image-based driver assistance system. Dual-camera stereo vision algorithm for the distance measurement for the detected vehicle and multi-line merge function for the lane detection are implemented via lab-made library and calibrated off-line. A lab-made library developed via programming language is written and compiled for low computing-power consumption and rapidly calculating for the real-time purpose. To save the computing power consumption, some proper region of interest of vehicle detection and lane detection are applied. Finally, this system has been preliminary implemented on a test vehicle and driven on various roads over tens of miles and reach around 4 similar to 5 frame per seconds via portable embedded system.