Browsing by Author "Lin, Chia-Feng"

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A fault-tolerant ONVIF protocol extension for seamless surveillance video stream recording
(2018-01-01)
Lin, Chia-Feng
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Chiao, Hsin-Ta
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Sheu, Ruey-Kai
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Chang, Yue-Shan
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Yuan, Shyan-Ming
ONVIF (Open Network Video Interface Forum) is an importance industrial standard for the video surveillance field. There are over 8000 ONVIF-compliant IP cameras (i.e., ONVIF NVT) and network video recorders (i.e., ONVIF NVS) from various vendors listed on the ONVIF official website. However, because the current ONVIF specifications do not support any fault-tolerant functions to handle NVS failure, in this paper we propose a fault tolerant solution for ONVIF NVS and try to minimize the modifications to the current ONVIF specifications in the proposed design. Besides, we also propose an extension to the ONVIF NVT for preventing the loss of captured NVT video data during the failover procedure triggered by NVS failure. Finally, we evaluate the following four performance metrics of the proposed fault-tolerant ONVIF surveillance system: the maximal video local cache time supported by an NVT, the response time for accessing an ONVIF web service, the interrupt duration of video recording due to NVS failure, and the live video black out time observed by a video management system. Since the experimental results are all within the acceptable range for a real fault-tolerant video surveillance system in the real world, the experiences provided by this paper is a good reference for improving the fault-tolerant capabilities of the ONVIF video surveillance systems. (C) 2017 Elsevier B.V. All rights reserved.
A Fault-Tolerant ONVIF Standard Extension for Cloud-Based Surveillance Systems
(2017-01-01)
Chiao, Hsin-Ta
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Lin, Chia-Feng
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Chang, Yue-Shan
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Sheu, Ruey-Kai
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Chen, Lung-Pin
ONVIF (Open Network Video Interface Forum) is a popular standard for the video surveillance industries. Since ONVIF specifications do not provide fault-tolerant functions to deal with NVT (Network Video Transmitter) or NVS (Network Video Storage) failure, we propose a fault-tolerant solution for both ONVIF NVT and NVS in this paper. The proposed fault-tolerant extension is also possible to be deployed over cloud-based environments, such as IaaS (Infrastructure as a Service) platforms. The proposed solution is evaluated by the following three performance metrics: the access response time for ONVIF web services, the video recording interrupt duration due to NVS failure, and the video black out time of the surveillance video monitoring system. The experimental results show that all the metrics are within the acceptable range for a real world video surveillance system.
A framework for scalable cloud video recorder system in surveillance environment
(2012)
Lin, Chia-Feng
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Yuan, Shyan-Ming
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Leu, Muh-Chyi
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Tsai, Ching-Tsorng
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資訊工程學系
In recent years, video surveillance industry has encountered huge evolution. First, the IP based video cameras are gradually replacing the market share of Closed-circuit television (CCTV). Second, hardware and software based network video record come to market to support more amounts of camera sources. However, pure NVR hardware or software which is installed on single physical machine may reach maximum storage or throughput limitation due to predefined resource limitation. In this paper, we proposed a prototype of cloud based video recorder system under Infrastructure as a Service (IaaS) abstraction layer in cloud computing domain. This system provides scalable video recording, backup and monitoring features. Furthermore, this system was implemented using Hadoop distributed file system to store video streaming. In this way, Map / Reduce mechanism could be used to support intelligent video analysis tasks. The paper shares a good experience while design unlimited resource video recording system.
A relaxable service selection algorithm for QoS-based web service composition
(2011-12-01)
Lin, Chia-Feng
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Sheu, Ruey-Kai
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Chang, Yue-Shan
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Yuan, Shyan-Ming
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資訊工程學系
Context: Web services are emerging technologies that enable application to application communication and reuse of autonomous services over Web. Composition of web services is a concept of integrating individual web services to conduct complex business transactions based on functionality and performance constraints Objective: To satisfy user requirements, technologies of Quality of service (QoS)-based web service composition (QWSC) are widely used to build complex applications by discovering the best-fit web services in term of QoS. Method: In this paper, a QoS-based service selection (RQSS) algorithm is proposed to help composite web application development by discovering feasible web services based on functionalities and QoS criteria of user requirements. The RQSS recommends prospective service candidates to users by relaxing QoS constraints if no suitable or available web service could exactly fulfill user requirements. Results: A generic framework is implemented to demonstrate the feasibility and performance of RQSS by adapting WS-BPEL standards, and can be reused for QoS-based web composition applications. Conclusion: The experimental results show that the RQSS algorithm indeed performs well and increases the system availability and reliability. (C) 2011 Elsevier B.V. All rights reserved.
Annotating Learning Materials on Moodle LMS
(2009)
Lin, Hsien-Tang
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Wang, Chih-Hua
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Lin, Chia-Feng
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Yuan, Shyan-Ming
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資訊工程學系
Learning management system (LMS) plays a critical role in current pedagogy. Along with the concept of WEB 2.0, web has become an interactive platform for contribution and collaboration. Moodle open source LMS is one of the most popular learning management systems currently. It will be valuable for the learners to view the teaching materials online and perform annotating operations on them which are traditionally executed on printed materials. To meet these requirements, a Moodle module: Learning Annotation for Moodle (LAM) was built. With this module, students can see both their own annotations and different thoughts in other students\' mind. Instructors can promote teaching by viewing students\' annotations.
Distributed Systems Management for Enterprise Web Services Environment
(2009)
Lin, Chia-Feng
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Wu, Ruey-Shyang
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Yuan, Shyan-Ming
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Chen, Kuan-Yu
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資訊工程學系
In this research, we simplify Web Services Distributed Management (WSDM) interfaces developing effort. The interfaces are generated by program code that must be created during development. Developers do not have to understand all Web services standards. On the other hand, the management system should provide message flow oriented management atomically without modifying service code. Enter prise can control all flows and review them at any time. Enterprise can build a quickly, efficient and extensible management system in the Web services environment
Effect of AlInGaN barrier layers with various TMGa flows on optoelectronic characteristics of near UV light-emitting diodes grown by atmospheric pressure metalorganic vapor phase epitaxy
(2011-08-01)
Fu, Yi-Keng
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Lu, Yu-Hsuan
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Jiang, Ren-Hao
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Chen, Bo-Chun
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Fang, Yen-Hsiang
Near ultraviolet light-emitting diodes (LEDs) with quaternary AlInGaN quantum barriers (QBs) are grown by atmospheric pressure metalorganic vapor phase epitaxy. The indium mole fraction of AlInGaN QB could be enhanced as we increased the TMG flow rate. Both the wavelength shift in EL spectra and forward voltage at 20 mA current injection were reduced by using AlInGaN QB. Under 100 mA current injection, the LED output power with Al(0.089)In(0.035)Ga(0.876)N QB can be enhanced by 15.9%, compared to LED with GaN QB. It should be attributed to a reduction of lattice mismatch induced polarization mismatch in the active layer. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.
Fabricated nano-disk InGaN/GaN multi-quantum well of the inverse hexagonal pyramids
(2008-02-01)
Yang, Chung-Chleh
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Dai, Jing-He
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Jiang, Ren Hao
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Zheng, Jing-Hul
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Lin, Chia-Feng
Self-assembled inverted hexagonal pyramids with GaN:Mg and InGaN/GaN multi-quantum-well (MQW) structures were formed through photoelectrochemical wet etching. The formation mechanism of the inverted hexagonal pyramid consisted with a lateral etching process of the InGaN/GaN active layer, bottom-up etching process from N-face GaN direction, and anisotropic etching process. The Photoluminescence (PL) intensity of GaN:Mg peak was enhanced in this inverted hexagonal pyramid caused by the quantum confinement effect of this nano-structure. These inverted hexagonal pyramids, consisting of the p-type GaN:Mg, nano-disk InGaN/GaN active layer, and n-type GaN:Si layer, are suitable for nano-scale optoelectronic devices. (c) 2007 Published by Elsevier Ltd.
Mesoporous GaN for Photonic Engineering-Highly Reflective GaN Mirrors as an Example
(2015-07-01)
Zhang, Cheng
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Park, Sung Hyun
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Chen, Danti
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Lin, Da-Wei
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Xiong, Wen
A porous medium is a special type of material where voids are created in a solid medium. The introduction of pores into a bulk solid can profoundly affect its physical properties and enable interesting mechanisms. In this paper, we report the use of mesoporous GaN to address a long-standing challenge in GaN devices: tuning the optical index in epitaxial structures without compromising the structural and electrical properties. By controlling the doping and electrochemical etching bias, we are able to control the pore morphology from macro- to meso- and microporous. The meso- and microporous GaN can be considered a new form of GaN with unprecedented optical index tunability. We examine the scattering loss in a porous medium quantitatively using numerical, semiempirical, and experimental methods. It is established that the optical loss due to scattering is well within the acceptable range. While being perfectly lattice-matched to GaN, the porous GaN layers are found to be electrically highly conductive. As an example of optical engineering, we demonstrate record high reflectances (R > 99.5%) from epitaxial mesoporous GaN mirrors that can be controllably fabricated, a result that is bound to impact GaN opto and photonic technologies.
Mobile Phone Enabled Barcode Recognition for Preferences Monitoring
(2011-01-01)
Daraghmi, Eman Yasser
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Lin, Chia-Feng
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Yuan, Shyan Ming
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資訊工程學系
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Department of Computer Science
In this paper, we present an innovative software system called Preferences Monitoring that makes use of modern middleware technologies and available hardware and communication systems. People can use the system to easily buy products that fit with their preferences. The system consists of mobile-phone side to scan product barcodes, submit user inquiries to a server, and display results. Results are related to whether users can eat or drink the product based on their preferences such as religion (no meat, beef, pork, or wine), or based on health settings such as allergies, chronic diseases or calories. Also, the system includes web services to facilitate user access to online profiles for editing accounts, viewing history-shopping and subscribing to other services. The preliminary results of testing our system show that the system can provide useful services for consumers. We also highlight some technical issues that arc related to reading barcode using mobile phones.
Mobile Phone Enabled Barcode Recognition for Preferences Monitoring
(2011-01-01)
Daraghmi, Eman Yasser
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Lin, Chia-Feng
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Yuan, Shyan Ming
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交大名義發表
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National Chiao Tung University
In this paper, we present an innovative software system called Preferences Monitoring that makes use of modern middleware technologies and available hardware and communication systems. People can use the system to easily buy products that fit with their preferences. The system consists of mobile-phone side to scan product barcodes, submit user inquiries to a server, and display results. Results are related to whether users can eat or drink the product based on their preferences such as religion (no meat, beef, pork, or wine), or based on health settings such as allergies, chronic diseases or calories. Also, the system includes web services to facilitate user access to online profiles for editing accounts, viewing history-shopping and subscribing to other services. The preliminary results of testing our system show that the system can provide useful services for consumers. We also highlight some technical issues that arc related to reading barcode using mobile phones.
Study of InGaN-Based Light-Emitting Diodes on a Roughened Backside GaN Substrate by a Chemical Wet-Etching Process
(2011-10-01)
Fu, Yi-Keng
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Chen, Bo-Chun
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Fang, Yen-Hsiang
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Jiang, Ren-Hao
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Lu, Yu-Hsuan
The InGaN-based light-emitting diodes (LEDs) with a roughened backside on the N-face surface of GaN substrate were fabricated through a chemical wet-etching process to increase light-extraction efficiency. The stable crystallographic etching planes were formed as the GaN {10 (11) over bar} planes. When the near-ultraviolet and blue LED were operated as a forward current of 20 mA, the output power of LEDs was improved from 13.2 and 19.9 mW to 25.6 and 24.0 mW, respectively. The different enhanced ratio is attributed to the different transmittance as a function of wavelength is caused from hexagonal pyramid on N-face GaN substrate after wet-etching process.
The effect of trimethylgallium flows in the AIInGaN barrier on optoelectronic characteristics of near ultraviolet light-emitting diodes grown by atmospheric pressure metalorganic vapor phase epitaxy
(2011-03-21)
Fu, Yi-Keng
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Jiang, Ren-Hao
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Lu, Yu-Hsuan
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Chen, Bo-Chun
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Xuan, Rong
The letter reports a theoretical and experimental study on the device performance of near ultraviolet light-emitting diodes (LEDs) with quaternary AlInGaN quantum barrier (QB). The indium mole fraction of AlInGaN QB could be enhanced as we increased the trimethylgallium flow rate. It was found the AlInGaN/InGaN LEDs can reduce forward voltage and improve light output power, compared with conventional GaN QB. By using advanced device simulation, it should be attributed to a reduction in lattice mismatch induced polarization mismatch in the active layer, which results in the suppression of electron overflow. (C) 2011 American Institute of Physics. [doi:10.1063/1.3571440]
Wet mesa etching process in InGaN-based light emitting diodes
(2008)
Yang, Chung-Chieh
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Lin, Chia-Feng
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Jiang, Ren-Hao
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Liu, Hsun-Chih
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Lin, Chun-Min
A photoelectrochemical wet mesa etching (WME) process was used to fabricate InGaN-based light emitting diodes (LEDs) as a substitute for the conventional plasma mesa dry etching process. The p-type GaN:Mg layer, InGaN active layer, and n-type GaN:Si layer were etched through a sequential photoelectrochemical oxidation and oxide-removing process to define the mesa region. The higher lateral wet-etching rate (similar to 3.4 mu m/h) of the InGaN active layer was observed to form a wider undercut structure which has 42.7% light output power enhancement compared to a conventional LED fabricated with the plasma dry etching process. The reverse current of a WME-LED was suppressed by avoiding plasma damage during the dry mesa etching process. (C) 2008 The Electrochemical Society.