學術出版;;Publications

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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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Demo Abstract: My Tai-Chi Book: A Virtual-Physical Social Network Platform
(2010-01-01)
Wu, Fang-Jing
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Huang, Chen-Shao
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Tseng, Yu-Chee
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資訊工程學系
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Department of Computer Science
While social networks on Web platforms have attracted a lot of interests, including more natural and physical inputs into such systems to enhance human interaction is desirable. Using body-area sensor networks (BSNs) to capture human motions opens up an opportunity toward this goal. These motivate us to design a novel virtual-physical social network platform 1 with typical social network functions and capable of receiving various inputs from remote BSNs. Through our platform, users can share conventional messages and images as well as sensory data in several interesting ways. We demonstrate a Tai-Chi exercise social network and some testing results.
Evacuation Time Analysis and Optimization for Distributed Emergency Guiding Based on Wireless Sensor Networks
(2012-01-01)
Chen, Lien-Wu
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Cheng, Jen-Hsiang
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Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
This paper proposes a load-balancing framework for emergency guiding based on wireless sensor networks. We design a load-balancing guiding scheme and derive an analytical model in order to reduce the total evacuation time of indoor people. The guiding scheme can provide the fastest path to an exit for people based on the evacuation time estimated by the analytical model. This is the first distributed solution which takes the corridor capacity and length, exit capacity, concurrent move, and people distribution into consideration for estimating evacuation time and planning escape paths. Through the proposed framework, the congestion of certain corridors and exits can be released to significantly reduce the total evacuation time. Analytical and simulation results show that our approach outperforms existing works, which can prevent people from following the local optimal guiding direction with the longer evacuation time in total. We also implement a prototype, called Load-balancing Emergency Guiding System (LEGS), which can compare evacuation time and guiding directions of existing schemes and ours under different people distribution.
Inference of Conversation Partners by Cooperative Acoustic Sensing in Smartphone Networks
(2016-06-01)
Chen, Yan-Ann
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Chen, Ji
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Tseng, Yu-Chee
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資訊工程學系
;
Department of Computer Science
A lot of personal daily contexts and activities may be inferred by analyzing acoustic signals in vicinity. Conversations play an important role in one\'s social communications. In this work, we consider the inference of conversation partners via acoustic sensing conducted by a group of smartphones in vicinity. By considering the continuity and overlap of speeches, we propose novel inference methods to identify conversational relationships among co-located users. In our system, each smartphone individually processes the acoustic data to understand its owner\'s talking turns and emotions. Via direct wireless communications, smartphones then cooperatively conduct the inference to retrieve conversational groups. Compared to existing work, which only exploits peer-to-peer conversational relationships, our approach is able to capture group conversational relationships in a more real-time manner. A prototype on Android smartphones is demonstrated to verify the feasibility of our approach. We also collect conversation data from movie clips and real life with 2 to 14 speakers to validate our result, which shows promising performance.
Distributed Emergency Guiding with Evacuation Time Optimization Based on Wireless Sensor Networks
(2016-02)
Chen, Lien-Wu
;
Cheng, Jen-Hsiang
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
This paper proposes a load-balancing framework for distributed emergency guiding based on wireless sensor networks. A load-balancing guiding scheme is designed and an analytical model is derived to reduce the total evacuation time of people indoors. The guiding scheme can provide the fastest path for people to reach an exit according to the evacuation time estimated using the analytical model. Based on thorough research, this is the first distributed solution in which corridor capacity and length, exit capacity, and the concurrent movement and distribution of people are considered in estimating the evacuation time and planning escape paths. Using the proposed framework, congestion in corridors and at exits can be eased to substantially reduce the total evacuation time. Analytical and simulation results show that this approach outperforms existing schemes and can prevent people from following local-optimal guiding directions that increase the evacuation time. A prototype called the Load-balancing Emergency Guiding System (LEGS) is implemented; this system can be used to compare the evacuation times and guiding directions provided by existing schemes and the proposed scheme for various distributions of people.
A Framework for Simultaneous Message Broadcasting Using CDMA-Based Visible Light Communications
(2015-12-01)
Chen, Yan-Ann
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Chang, Yi-Ting
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Tseng, Yu-Chee
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Chen, Wen-Tsuen
;
資訊工程學系
Internet of Things applications are fast growing recently. One of the things that has a lot of potential is the lighting equipment since it is widely used in our daily life. Recently, the technology of visible light communication (VLC) has been widely discussed. VLC has several advantages, such as freedom of license, line-of-sight security, and less health concern compared with radio-based systems. In addition, the rapid progress of light emitting diode (LED) technology by solid-sate lighting allows VLC to be easily deployed and integrated with the existing lighting infrastructure at low costs. However, VLC, when integrated with lighting infrastructure, is usually for one-way communication and is highly sensitive to external interfering light. Thus, transmitting or broadcasting multiple messages simultaneously over a visible light channel without any preprocessing may result in serious collisions. In this paper, we propose a framework to tackle these problems by optical code division multiple access (CDMA) for VLC. With our approach, a VLC receiver can enter an environment without any prior configuration and can be designed with simple hardware. Even a mobile device with a high-resolution photodiode sensor can be used as a receiver. We demonstrate an application of indoor positioning by querying the location service provider on the Internet with the IDs decoded from the received light signals. The prototyping results reveal some communication properties of CDMA-based VLC and its potential for indoor positioning applications.
Optimal Path Planning With Spatial-Temporal Mobility Modeling for Individual-Based Emergency Guiding
(2015-12-01)
Chen, Lien-Wu
;
Cheng, Jen-Hsiang
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
This paper proposes an individual-based framework for emergency guiding. The spatial-temporal mobility of all people is modeled to determine a dedicated path that provides the shortest evacuation time for each person. According to our review of relevant research, this is the first optimal solution without using time-expanded graphs, and corridor capacities and lengths, exit capacities, concurrent motion, and distribution of people are considered to minimize evacuation time. We prove that the proposed path planning algorithm is optimal and analyze its time and space complexity. The proposed framework can be used to estimate the evacuation time for each person accurately and evenly distribute evacuation load among exits to achieve the most efficient load balance. In the proposed framework, the congestion in all corridors and exits can be alleviated to maximally reduce the total evacuation time. Simulation results show that our approach outperforms existing schemes, and can be used to determine an optimal escape path for each person and, thus, achieve the shortest total evacuation time.
Compression and storage schemes in a sensor network with spatial and temporal coding techniques
(2008)
Wang, You-Chiun
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Hsieh, Yao-Yu
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Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
Wireless sensor networks provide a convenient manner to monitor the physical environments. How to extend the network lifetime by reducing the amount of message transmissions is a critical issue. In this paper, we propose a multi-resolution compression and storage (MCS) framework to compress and preserve sensing data in a wireless sensor network. Our MCS framework adopts spatial and temporal compression schemes to reduce the amount of message transmissions, so the network lifetime can he prolonged and the network congestion can be alleviated. In addition, we also develop a storage mechanism to maintain sensing data in sensor nodes, so that users can query more detailed data when necessary. Our proposed methods consider the hardware limitations of sensor nodes. We also implement a prototyping system on the MICAz Mote platform.
ZigBee-based long-thin wireless sensor networks: address assignment and routing schemes
(2013)
Pan, Meng-Shiuan
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Tseng, Yu-Chee
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資訊工程學系
;
Department of Computer Science
Although Wireless Sensor Networks (WSNs) have been extensively researched, its deployment is still a big concern. This paper makes two contributions to this issue. First, we promote a new concept of Long-Thin (LT) topology for WSNs, where a network may have a number of linear paths of nodes as backbones connecting to each other. These backbones are to extend the network to the intended coverage areas. At the first glance, a LT WSN only seems to be a special case of numerous WSN topologies. However, we observe, from real deployment experiences, that such a topology is quite general in many applications and deployments. The second contribution is that we show that the address assignment and thus the tree routing scheme defined in the original ZigBee specification may work poorly, if not fail, in a LT topology. We then propose simple, yet efficient, address assignment and routing schemes for a LT WSN. Simulation results are reported.
k-Angle Object Coverage Problem in a Wireless Sensor Network
(2012-12-01)
Tseng, Yu-Chee
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Chen, Po-Yu
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Chen, Wen-Tsuen
;
資訊工程學系
;
Department of Computer Science
One of the fundamental issues in sensor networks is the coverage problem, which reflects how well a field is monitored or tracked by sensors. Various versions of this problem have been studied, such as object, area, barrier, and hole coverage problems. In this paper, we define a new k-angle object coverage problem in a wireless sensor network. Each sensor can only cover a limited angle and range, but can freely rotate to any direction to cover a particular angle. Given a set of sensors and a set of objects at known locations, the goal is to use the least number of sensors to k-angle-cover the largest number of objects such that each object is monitored by at least k sensors satisfying some angle constraint. We propose centralized and distributed polynomial-time algorithms to solve this problem. Simulation results show that our algorithms can be effective in maximizing coverage of objects. A prototype system is developed to demonstrate the usefulness of angle coverage.
Data Compression by Temporal and Spatial Correlations in a Body-Area Sensor Network: A Case Study in Pilates Motion Recognition
(2011-10-01)
Wu, Chun-Hao
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Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
We consider a body-area sensor network (BSN) consisting of multiple small, wearable sensor nodes deployed on a human body to track body motions. Concerning that human bodies are relatively small and wireless packets are subject to more serious contention and collision, this paper addresses the data compression problem in a BSN. We observe that, when body parts move, although sensor nodes in vicinity may compete strongly with each other, the transmitted data usually exist some levels of redundancy and even strong temporal and spatial correlations. Unlike traditional data compression approaches for large-scale and multihop sensor networks, our scheme is specifically designed for BSNs, where nodes are likely fully connected and overhearing among sensor nodes is possible. In our scheme, an offline phase is conducted in advance to learn the temporal and spatial correlations of sensing data. Then, a partial ordering of sensor nodes is determined to represent their transmission priorities so as to facilitate data compression during the online phase. We present algorithms to determine such partial ordering and discuss the design of the underlying MAC protocol to support our compression model. An experimental case study in Pilates exercises for patient rehabilitation is reported. The results show that our schemes reduce more than 70 percent of overall transmitted data compared with previous approaches.

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