Browsing by Author "Hu, Shu-Chiung"

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A sensor-based sun-tracking energy harvest system
(2015-01-01)
Tsai, Chia-Hung
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Hu, Shu-Chiung
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Huang, Chung-Hsiang
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Tseng, Yu-Chee
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資訊工程學系
Recent study has shown that the energy gain of a solar panel will be significantly influenced by the incidence angle of the sun radiation. The main goal of this paper is to present a sensor-based sun-tracking system. First, we design a sensing tower for measuring the direction of sun radiation. Then we design a sun-tracking algorithm, which adopts an iterative process to identify the direction of sun radiation to the earth\'s surface. This information is then passed to the nearby solar panels to adjust their angles. We have also developed a prototype and conducted several simulations to verify our sun-tracking system. Simulation results show that our system has better performance on the solar energy generation than existing ones.
A Vehicular Wireless Sensor Network for CO(2) Monitoring
(2009-01-01)
Hu, Shu-Chiung
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Wang, You-Chiun
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Huang, Chiuan-Yu
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Tseng, Yu-Chee
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資訊工程學系
Micro-climate monitoring usually requires deploying a large number of measurement tools. By adopting vehicular wireless sensor networks (VSNs), we can use fewer tools to achieve fine-grained monitoring. This work proposes a VSN architecture to realize micro-climate monitoring based on GSM short messages and availability of GPS receivers on vehicles. We demonstrate our prototype of a Zig Bee-based car network to monitor the concentration of carbon dioxide (CO(2)) gas in areas of interest. The reported data are sent to a server, which is integrated with Google Maps as our user interface. Since mobility of these vehicles is not controllable and sending short messages incurs charges, we also design an on-demand approach to adjust vehicles' reporting rates to balance between the micro-climate accuracy and the communication cost.
A Vehicular Wireless Sensor Network for CO2 Monitoring
(2009-01-01)
Hu, Shu-Chiung
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Wang, You-Chiun
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Huang, Chiuan-Yu
;
Tseng, Yu-Chee
;
資訊工程學系
Micro-climate monitoring usually requires deploying a large number of measurement tools. By adopting vehicular wireless sensor networks (VSNs), we can use fewer tools to achieve fine-grained monitoring. This work proposes a VSN architecture to realize micro-climate monitoring based on GSM short messages and availability of GPS receivers on vehicles. We demonstrate our prototype of a Zig Bee-based car network to monitor the concentration of carbon dioxide (CO2) gas in areas of interest. The reported data are sent to a server, which is integrated with Google Maps as our user interface. Since mobility of these vehicles is not controllable and sending short messages incurs charges, we also design an on-demand approach to adjust vehicles' reporting rates to balance between the micro-climate accuracy and the communication cost.
An adaptive Paris Metro Pricing scheme for mobile data networks
(2016-11-12)
Huang, Huai-Sheng
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Hu, Shu-Chiung
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Lee, Po-Han
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Tseng, Yu-Chee
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資訊工程學系
Because static pricing models (such as flat-rate or tiered-rate models) cannot improve user utility for subscribers and ease network congestion for operators during peak time, Smart Data Pricing has become an important incentive for mobile data markets. Paris Metro Pricing (PMP), which is a static pricing mode inspired by the pricing model for the Paris metro system, uses differentiated prices to motivate users to choose different train classes. Before choosing a class, people will consider their expected quality of service versus the prices that they are willing to pay. Even though PMP cannot guarantee the actual quality of service during service time, a balance between users\' utilities and operators\' revenue is achieved. In this paper, we propose an adaptive PMP scheme, so-called APMP, which determines the dynamic access prices of different classes for the next 24h. The accessible prices should try to increase the revenue while operators can serve more subscribers. Our simulation results show that APMP can significantly improve total revenue and average revenue per user for the operator. Copyright (c) 2016 John Wiley & Sons, Ltd.
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.
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
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資訊工程學系
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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.
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.
Measuring air quality in city areas by vehicular wireless sensor networks
(2011-11-01)
Hu, Shu-Chiung
;
Wang, You-Chiun
;
Huang, Chiuan-Yu
;
Tseng, Yu-Chee
;
資訊工程學系
This paper considers a micro-climate monitoring scenario, which usually requires deploying a large number of sensor nodes to capture environmental information. By exploiting vehicular sensor networks (VSNs), it is possible to equip fewer nodes on cars to achieve fine-grained monitoring. Specifically, when a car is moving, it could conduct measurements at different locations, thus collecting lots of sensing data. To achieve this goal, this paper proposes a VSN architecture to collect and measure air quality for microclimate monitoring in city areas, where nodes' mobility may be uncontrollable (such as taxis). In the proposed VSN architecture, we address two network-related issues: (1) how to adaptively adjust the reporting rates of mobile nodes to satisfy a target monitoring quality with less communication overhead and (2) how to exploit opportunistic communications to reduce message transmissions. We propose algorithms to solve these two issues and verify their performances by simulations. In addition, we also develop a ZigBee-based prototype to monitor the concentration of carbon dioxide (CO(2)) gas in city areas. (C) 2011 Elsevier Inc. All rights reserved.