Browsing by Author "Pan, Meng-Shiuan"

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A Lightweight Network Repair Scheme for Data Collection Applications in ZigBee WSNs
(2009-09-01)
Pan, Meng-Shiuan
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
Data collection is a fundamental operation in wireless sensor networks (WSNs). In [4], a quick convergecast solution is proposed for data collection in a ZigBee beacon-enabled tree-based WSN. However, it does not consider the network repair issue. When a ZigBee router loses its link to its parent, all its descendants have to rejoin the network. The rejoining procedure is time-consuming and may incur high communication overheads. The proposed network repair scheme consists of a regular repair and an instant repair schemes. Periodically, the network coordinator can issue regular repair to refresh the network (so as to keep the network in good shape). During normal operations, if a router loses its parent, it tries instant repair to reconnect to a new parent. Our design thus improves over ZigBee in that nodes can continue their operations even during instant repair.
A WSN-Based Intelligent Light Control System Considering User Activities and Profiles
(2008-09-01)
Pan, Meng-Shiuan
;
Yeh, Lun-Wu
;
Chen, Yen-Ann
;
Lin, Yu-Hsuan
;
Tseng, Yu-Chee
Recently, wireless sensor networks (WSNs) have been widely discussed in many applications. In this paper, we propose a WSN-based intelligent light control system for indoor environments. Wireless sensors are responsible for measuring current illuminations. Two kinds of lighting devices, namely, whole lighting and local lighting devices, are used to provide background and concentrated illuminations, respectively. Users may have various illumination requirements according to their activities and profiles. An illumination requirement is as the combination of background and concentrated illumination demands and users' locations. We consider two requirement models, namely, binary satisfaction and continuous satisfaction models, and propose two decision algorithms to determine the proper illuminations of devices and to achieve the desired optimization goals. Then, a closed-loop device control algorithm is applied to adjust the illumination levels of lighting devices. The prototyping results verify that our ideas are practical and feasible.
Address assignment and routing schemes for ZigBee-based long-thin wireless sensor networks
(2008)
Pan, Meng-Shiuan
;
Fang, Hua-Wei
;
Liu, Yung-Chih
;
Tseng, Yu-Chee
;
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.
An Energy-Efficient Multicast Protocol for ZigBee-based Networks
(2016)
Hu, Shu-Chiung
;
Tsai, Chia-Hung
;
Lu, Yi-Chen
;
Pan, Meng-Shiuan
;
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.
Cross-Layer, Energy-Efficient Design for Supporting Continuous Queries in Wireless Sensor Networks: A Quorum-Based Approach
(2009-11-01)
Tsai, Chia-Hung
;
Hsu, Tsu-Wen
;
Pan, Meng-Shiuan
;
Tseng, Yu-Chee
;
資訊工程學系
Power saving and query processing are two major concerns in a wireless sensor network. Each of these two issues has been intensively studied separately in the literature. In this work, we are interested in linking the asynchronous power-saving protocol and the continuous query-processing problem together. A cross-layer solution is proposed. On the MAC layer, we propose to use the grid-quorum system (Tseng et al., Computer Networks, 43(3):317-337, 2003) to serve as the underlying power-saving framework. On the network layer, we propose to find query paths based on the power cost incurred by grid quorums used by nodes along a path. We show how these two layers interwork with each other to support continuous queries in an energy-efficient way.
Quick convergecast in ZigBee beacon-enabled tree-based wireless sensor networks
(2008-03-25)
Pan, Meng-Shiuan
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
Convergecast is a fundamental operation in wireless sensor networks. Existing convergecast solutions have focused on reducing latency and energy consumption. However, a good design should be compliant to standards, in addition to considering these factors. Based on this observation, this paper defines a minimum delay beacon scheduling problem for quick convergecast in ZigBee tree-based wireless sensor networks and proves that this problem is NP-complete. Our formulation is compliant with the low-power design of IEEE 802.15.4. We then propose optimal solutions for special cases and heuristic algorithms for general cases. Simulation results show that the proposed algorithms can indeed achieve quick convergecast. (C) 2007 Elsevier B.V. All rights reserved.
The Orphan Problem in ZigBee Wireless Networks
(2009-11-01)
Pan, Meng-Shiuan
;
Tsai, Chia-Hung
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
ZigBee is a communication standard which is considered to be suitable for wireless sensor networks. In ZigBee, a device (with a permanent 64-bit MAC address) is said to join a network if it can successfully obtain a 16-bit network address from a parent device. Parent devices calculate addresses for their child devices by a distributed address assignment scheme. This assignment is easy to implement, but it restricts the number of children of a device and the depth of the network. We observe that the ZigBee address assignment policy is too conservative, thus usually making the utilization of the address pool poor. Those devices that cannot receive network addresses will be isolated from the network and become orphan nodes. In this paper, we show that the orphan problem can be divided into two subproblems: the bounded-degree-and-depth tree formation (BDDTF) problem and the end-device maximum matching (EDMM) problem. We then propose algorithms to relieve the orphan problem. Our simulation results show that the proposed schemes can effectively reduce the number of orphan devices compared to the ZigBee strategy.
The Orphan Problem in ZigBee-based Wireless Sensor Networks
(2007)
Pan, Meng-Shiuan
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
ZigBee is a standard which is considered to be suitable for wireless sensor networks. In ZigBee, a device is said to join a network if it call obtain a network address from a parent device. Devices calculate addresses for their child devices by a distributed address assignment scheme. This assignment is easy to implement, but it restricts the number of children of a device and the depth of the network. We observe that if one uses the random formation policy specified in ZigBee, the utilization of the address pool will be very low. Those devices that call not receive network addresses will be isolated from the network and become orphan nodes. In this paper, we model the orphan problem by two subproblems: the bounded-degree-and-depth tree formation (BDDTF) problem and the end-device maximum matching (EDMM) problem. We then present solutions to these problems. The results can be applied to network formation in ZigBee networks.
Wireless sensor networks for emergency navigation
(2006-07-01)
Tseng, Yu-Chee
;
Pan, Meng-Shiuan
;
Tsai, Yuen-Yung
;
資訊工程學系
;
Department of Computer Science
In an emergency, wireless network sensors combined with a navigation algorithm could help safely guide people to a building exit while helping them avoid hazardous areas.
ZigBee-based long-thin wireless sensor networks: address assignment and routing schemes
(2013)
Pan, Meng-Shiuan
;
Tseng, Yu-Chee
;
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.