Browsing by Author "Lee, Cheng-Lung"

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Application of Wearable Devices in Crime Scene Investigation and Virtual Reality
(2019-01-01)
Lee, Cheng-Lung
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Fang, Yuan
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Huang, Yi-Hsin
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Lee, Szu-Hao
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Yeh, William Chen-Chung
In 2009, the United States National Academy of Sciences (NAS) proposed a list of suggestions to forensic-related issues, with emphasis on the correct use of modern technology to improve on-the-scene investigation. To ensure that the scene is fully detailed, a team of personnel including but not limited to photographer, videographer, evidence collector, and those who estimate and mark the scene are involved. However, traditional way of investigation not only utilizes too much manpower, but the destruction of crime scene is also an unavoidable problem we faced. Hence, the urgent tasks to be improved now are to protect, record and efficiently investigate the crime scene, to instantly deliver evidences for data matching, as well to provide an option to setup a video conference with experts in Forensics fields to assist officers on scene. The research integrates the concepts of "Wearable Devices" and "Forensic Cloud Computing", to showcase the benefits of Forensic database. Through cloud sharing, it is now possible to use portable devices for all on-the-scene records, video taking, and on-the-spot graphic detailing. Forensic Cloud is used with wireless and 3G/4G to deliver evidences and information. The user friendly design and mobile computing can be integrated together with instant communication and on-line forensic database. The research not only utilizes the latest technology to protect the integrity of crime scene, but will make a breakthrough in Crime Scene Investigation (CSI)-cost reduction in manpower, as well as enhancing the efficiency and effectiveness of investigation. Finally, with this research, we hope to strengthen scientific evidence, to push forward judiciary reformation, and to reduce the possibility of erroneous conviction.
CHANNEL-OPTIMIZED ERROR MITIGATION FOR DISTRIBUTED SPEECH RECOGNITION OVER WIRELESS NETWORKS
(2009)
Lee, Cheng-Lung
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Chang, Wen-Whei
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電信工程研究所
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Institute of Communications Engineering
This paper investigates the error mitigation algorithms for distributed speech recognition over wireless channels. A MAP symbol decoding algorithm which exploits the combined a priori information of source and channel is proposed. This is used in conjunction with a modified BCJR algorithm for decoding convolutional codes based on sectionalized code trellises. Performance is further enhanced by the use of the Gilbert channel model that more closely characterizes the statistical dependencies between channel bit errors. Experiments on Mandarin digit string recognition task indicate that our proposed mitigation scheme achieves high robustness against channel errors.
Perceptual-Based Playout Mechanisms for Multi-Stream Voice over IP Networks
(2007)
Wu, Chun-Feng
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Lee, Cheng-Lung
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Chang, Wen-Whei
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電信工程研究所
;
Institute of Communications Engineering
cPacket loss and delay are two essential problems to real-time voice transmission over best-effort packet networks. In the proposed system, multiple descriptions of the speech are transmitted to take advantage of largely uncorrelated delay and loss characteristics on different network paths. Adaptive playout scheduling of multiple voice streams is formulated as an optimization problem leading to a better delay-loss tradeoff. Also proposed is a perceptually motivated optimization criterion based on a simplified version of the ITU-T E-model. Experimental results show that the proposed playout buffer algorithm improves the delay-loss tradeoff as well as speech reconstruction quality.