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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
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資訊工程學系
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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.
Distributed Emergency Guiding with Evacuation Time Optimization Based on Wireless Sensor Networks
(2016-02)
Chen, Lien-Wu
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Cheng, Jen-Hsiang
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Tseng, Yu-Chee
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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.
An Energy-Efficient Multicast Protocol for ZigBee-based Networks
(2016)
Hu, Shu-Chiung
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Tsai, Chia-Hung
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Lu, Yi-Chen
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Pan, Meng-Shiuan
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Tseng, Yu-Chee
Recently, many Internet of Things (IoT) or wireless sensor network (WSN) applications adopt ZigBee as their communication protocol. In these applications, messages may need to be disseminated to some specific objects or nodes using multicast transmissions. However, we observe that the original ZigBee multicast protocol causes extremely high packet overhead and energy consumption. In this work, we propose a ZigBee-compatible energy efficient multicast protocol, which allows nodes to execute the designed procedures in a distributed manner. By our scheme, each node uses the designed maintenance module to manage its neighbors. When multicasting, a node utilizes the designed multicasting module to compete for being a relay node by the proposed backoff mechanism. In addition, each node overhears its neighbors\' broadcasts to avoid unnecessary transmissions and to ensure that the transmitted multicast packets are successfully received. Our results indicate that the proposed protocol can indeed lengthen network lifetime, reduce redundant packets, and preserve network reliability.
Distributed Address Assignment with Address Borrowing for ZigBee Networks
(2014-01-01)
Hu, Shu-Chiung
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Lin, Cheng-Kuan
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Tseng, Yu-Chee
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Chen, Wen-Tsuen
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資訊工程學系
ZigBee is a popular communication standard for wireless sensor networks. It suggests a distributed address assignment mechanism (DAAM), which is easy to implement but may restrict the number of children of a router and the depth of the network. Since DAAM is too conservative, the utilization of the 16-bit address pool may become poor, causing the orphan problem. In this paper, we propose a distributed address assignment scheme by allowing a parent to borrow a subtree of address space from a neighbor to alleviate the orphan problem. When a new node tries to associate with a parent router which has no free address, this parent router will inquire its 2hop neighbors for lending a subtree of free address space. We also propose a light-weight routing to support one-to-one routing in this environment.
Automatic Parameter Selection for the ZigBee Distributed Address Assignment Mechanism
(2013-01-01)
Hu, Shu-Chiung
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Lin, Cheng-Kuan
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Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
Addressing in wireless sensor networks is to assign each newly-joining device a unique address. However, to allot the naming space in a large-scale distributed wireless sensor network is not an easy task. ZigBee is a popular communication standard for wireless sensor networks. It suggests a distributed address assignment mechanism. A parent device can calculate network addresses for its child devices without communicating with other devices. However, the parameter configuration of this mechanism strictly restricts the number of children of a device and the depth of the network. ZigBee does not recommend suitable parameters. The improper parameter configuration usually makes many devices isolated from the network which become orphan devices. In this paper, we propose two automatic parameter selection schemes for ZigBee address assignment scheme by probing the network and then selecting parameters in advance to alleviate the orphan problem. They can automatically suggest proper parameters for different network topologies and thus help the original ZigBee address assignment mechanism to effectively reduce orphans.
Address assignment and routing schemes for ZigBee-based long-thin wireless sensor networks
(2008)
Pan, Meng-Shiuan
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Fang, Hua-Wei
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Liu, Yung-Chih
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Tseng, Yu-Chee
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資訊工程學系
Wireless sensor networks (WSNs) have been extensively, researched recently. This paper makes two contributions to this field. First, we promote a new concept of long-thin (LT) topology for WSNs, where a network may have a member 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 experiments, 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 thus propose simple, yet efficient, address assignment and routing schemes for a LT WSN. Simulation results and prototyping experiences are also reported.
Energy-Balanced Dispatch of Mobile Sensors in a Hybrid Wireless Sensor Network
(2010-12-01)
Wang, You-Chiun
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Peng, Wen-Chih
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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
We consider a hybrid wireless sensor network with static and mobile nodes. Static sensors monitor the environment and report events occurring in the sensing field. Mobile sensors are then dispatched to visit these event locations to conduct more advanced analysis. A big challenge is how to schedule these mobile sensors' traveling paths in an energy-balanced way so that their overall lifetime is maximized. We formulate this problem as a multiround sensor dispatch problem and show it to be NP-complete. Then, we propose a centralized and a distributed heuristics to schedule mobile sensors' traveling paths. Our heuristics allow arbitrary numbers of mobile sensors and event locations in each round and have an energy-balanced concept in mind. The centralized heuristic tries to minimize mobile sensors' moving energy while keeping their energy consumption balanced. The distributed heuristic utilizes a grid structure for event locations to bid for mobile sensors. Through simulations, we show the effectiveness of our schemes. This paper contributes in defining a more general multiround sensor dispatch problem and proposing energy-efficient solutions to it.
Energy-conserving data gathering by mobile mules in a spatially separated wireless sensor network
(2013-10-25)
Wu, Fang-Jing
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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
This paper considers a spatially separated wireless sensor network, which consists of a number of isolated subnetworks that could be far away from each other in distance. We address the issue of using mobile mules to collect data from these sensor nodes. In such an environment, both data-collection latency and network lifetime are critical issues. We model this problem as a bi-objective problem, called energy-constrained mule traveling salesman problem (EM-TSP), which aims at minimizing the traversal paths of mobile mules such that at least one node in each subnetwork is visited by a mule and the maximum energy consumption among all sensor nodes does not exceed a pre-defined threshold. Interestingly, the traversal problem turns out to be a generalization of the classical traveling salesman problem (TSP), an NP-complete problem. With some geometrical properties of the network, we propose some efficient heuristics for EM-TSP. We then extend our heuristics to multiple mobile mules. Extensive simulation results have been conducted, which show that our proposed solutions usually give much better solutions than most TSP-like approximations. Copyright (c) 2011 John Wiley & Sons, Ltd.
Deploying Sensors for Gravity Measurement in a Body-Area Inertial Sensor Network
(2013-05-01)
Wu, Chun-Hao
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Tseng, Yu-Chee
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資訊工程學系
;
Department of Computer Science
This paper deals with human posture tracking by deploying accelerometers on a human body. One fundamental issue in such scenarios is how to calculate the gravity. This is very challenging especially when the human body parts keep on moving. Fortunately, it is likely that there is a point of the body that touches the ground in most cases. This allows sensors to collaboratively calculate the gravity vector. Assuming multiple accelerometers being deployed on a rigid part of a human body, a recent work proposes a data fusion method to estimate the gravity vector on that rigid part. However, finding the optimal deployment of sensors that minimizes the estimation error of the gravity vector is not addressed. In this paper, we formulate the deployment optimization problem and propose two heuristics, called Metropolis-based method and largest-inter-distance-based method. Simulation and real experimental results show that our schemes are quite effective in finding near-optimal solutions for a variety of rigid body geometries.

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🏛️國立陽明交通大學機構典藏

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