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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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Design and implementation of a SIP-based mobile and vehicular wireless network with push mechanism
(2007-11-01)
Tseng, Yu-Chee
;
Chen, Jen-Jee
;
Cheng, Yu-Li
;
資訊工程學系
;
Department of Computer Science
As portable devices are gaining more popularity, maintaining Internet connectivity anytime and anywhere becomes critical, particularly for mobile and vehicular networks. Network mobility (NEMO) and Internet Protocol mobility are gaining more and more importance. In this paper, we develop a Session Initiation Protocol (SIP)-based mobile network architecture to support NEMO for vehicular applications. We propose to form a mobile ad hoc network (MANET) by the mobile hosts (MHs) inside a vehicle or a cluster of vehicles. The MANET is connected to the outside world via a SIP-based Mobile Network Gateway (SIP-MNG), which is equipped with one or multiple external wireless interfaces and some internal IEEE 802.11 interfaces. The external interfaces of the SIP-MNG support Internet connectivity by aggregating user traffic to and from the Internet. In addition, exploiting the session information carried by SIP signaling, the SIP-MNG supports resource management and call admission control for the MHs. However, wireless access incurs charges, power consumption, and overhead of mobility management. So, it is desirable to allow the SIP-MNG to disconnect its external interfaces when necessary. To guarantee that users inside the mobile network will not lose any incoming request, we propose a push mechanism through short message service to wake up these wireless interfaces in an on-demand manner. We show the detailed signaling to support such a mechanism. The proposed system is fully compatible with existing SIP standards. Our real prototyping experience and some experimental results are also reported.
Case study of an intelligent green store based on NFC technology
(2014)
Sha, D. Y.
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Perng, Der Baau
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Lai, Guo Liang
;
工業工程與管理學系
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Department of Industrial Engineering and Management
This study adopts an empirical case study that focuses on improving the process of products exhibit and sale in the store using NFC technology. Through intelligent interactive guide-shopping system proposed by this research, this case shows how to reduce the cost of products exhibition and simplify the sales process based on the NFC technology. Furthermore, this shopping flow not only enhances the shopping efficiency for consumers but also saves energy in the stores with less display space and marketing costs. The stores could also collect shopping information in order to realize the consumers\' behavior and then offer better service.
圖論在無線網路上之應用
(2011)
陳秋媛
;
CHEN CHIUYUAN
;
國立交通大學應用數學系（所）
我們可以用圖來做為一個無線網路的模型，在此模型下，每一個無線網路中的節點對應到圖中的一個點，若兩個無線網路中的節點彼此在對方的傳輸範圍內，則它們在圖中所對應的點有邊相連。在過去的十年中，圖論的一些理論確實被應用在解決無線網路的問題上，其中最有名的例子當屬「以連通的控制集做為無線網路的虛擬骨幹」，因此，若能使得連通的控制集中的點數愈少，就能使得對應的無線網路的虛擬骨幹中的節點數愈少，也愈能減少無線網路的維護成本。然而，細數到底有多少圖論的理論已被應用在解決無線網路的問題上時，就會知道這部份還有非常大的努力空間。本計畫之目的即在於探討圖論在無線網路中的應用，希望能將更多的圖論的理論應用在解決無線網路的問題以及設計有效率的演算法之上。
Intelligent medium access for mobile ad hoc networks with busy tones and power control
(2000-09-01)
Wu, SL
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Tseng, YC
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Sheu, JP
;
資訊工程學系
;
Department of Computer Science
In mobile ad hoc networks (MANETs), one essential issue is how to increase channel utilization while avoiding the hidden-terminal and the exposed-terminal problems. Several MAC protocols, such as RTS/CTS-based and busy-tone-based schemes, have been proposed to alleviate these problems. In this paper, we explore the possibility of combining the concept of power control with the RTS/CTS-based and busy-tone-based protocols to further increase channel utilization. A sender will use an appropriate power level to transmit its packets so as to increase the possibility of channel reuse. The possibility of using discrete, instead of continuous, power levels is also discussed. Through analyses and simulations, we demonstrate the advantage of our new MAC protocol. This, together with the extra benefits such as saving battery energy and reducing cochannel interference, does show a promising direction to enhance the performance of MANET's.
GRID: A fully location-aware routing protocol for mobile ad hoc networks
(2001)
Liao, WH
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Sheu, JP
;
Tseng, YC
;
資訊工程學系
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Department of Computer Science
A mobile ad hoc network (MANET) is one consisting of a set of mobile hosts capable of communicating with each other without the assistance of base stations. One prospective direction to assist routing in such an environment is to use location information provided by positioning devices such as global positioning systems (GPS). In this paper, we propose a new routing protocol called GRID. which tries to exploit location information in route discovery, packet relay, and route maintenance. Existing protocols, as compared to ours, are either not location-aware or partially location-aware in that location knowledge is not fully exploited in all these three aspects. One attractive feature of our protocol is its strong route maintenance capability - the intermediate hosts of a route can perform a "handoff" operation similar to that in cellular systems when it roams away to keep a route alive. This makes routes in the MANET more stable and insensitive to host mobility. Simulation results show that our GRID routing protocol can reduce the probability of route breakage, reduce the number of route discovery packets used, and lengthen routes' lifetime.
Providing service differentiation in wireless networks
(2001-04-01)
Lee, CL
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Chen, YC
;
Chen, JR
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資訊工程學系
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Department of Computer Science
Differentiated services: (Diffserv) model is one of the possible solutions for providing quality of service (QoS) on the Internet. Most existing approaches assume that the packet loss is an indication of network congestion and thus reduce the sending rates: of sources. For wireless networks, the assumption is not proper since packet losses may he caused by other reasons, such as fading and interference of the signal. Therefore, these approaches do not work well in wireless networks. In this paper, we propose an approach which is able to provide service differentiation in wireless environments. In our approach, the rate share of a connection is determined by the associated weight. By keeping a proper amount of extra data in the network, the proposed approach can achieve weighted proportional fairness, which can provide selective QoS without any particular support, from the network. We use the ns simulator to evaluate our approach. Simulation results show the validity of the proposed approach.
Termination detection protocols for mobile distributed systems
(2001-06-01)
Tseng, YC
;
Tan, CC
;
資訊工程學系
;
Department of Computer Science
This paper studies a fundamental problem, the termination defection problem, in distributed systems. Under a wireless network environment, we show how to handle the host mobility and disconnection problems. in particular, when some distributed processes are temporarily disconnected, we show how to capture a weakly terminated state where silence has been reached only by those currently connected processes. A user may desire to know such a state to tell whether the mobile distributed system is still running or is silent because some processes are disconnected. Our protocol tries to exploit the network hierarchy by combining two existing protocols together. It employs the weight-throwing scheme [9], [16], [21] on the wired network side, and the diffusion-based scheme [5], [13] on each wireless cell. Such a hybrid protocol can better pave the gaps of computation and communication capability between static and mobile hosts, thus more scalable to larger distributed systems. Analysis and simulation results are also presented.
The broadcast storm problem in a mobile ad hoc network
(2002)
Tseng, YC
;
Ni, SY
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Chen, YS
;
Sheu, JP
;
資訊工程學系
Broadcasting is a common operation in a network to resolve many issues. In a mobile ad hoc network (MANET) in particular, due to host mobility, such operations are expected to be executed more frequently (such as finding a route to a particular host, paging a particular host, and sending an alarm signal). Because radio signals are likely to overlap with others in a geographical area, a straightforward broadcasting by flooding is usually very costly and will result in serious redundancy, contention, and collision, to which we call the broadcast storm problem. In this paper, we identify this problem by showing how serious it is through analyses and simulations. We propose several schemes to reduce redundant rebroadcasts and differentiate timing of rebroadcasts to alleviate this problem. Simulation results are presented, which show different levels of improvement over the basic flooding approach.
Adaptive approaches to relieving broadcast storms in a wireless multihop mobile ad hoc network
(2003-05-01)
Tseng, YC
;
Ni, SY
;
Shih, EY
;
資訊工程學系
;
Department of Computer Science
In a multihop mobile ad hoc network, broadcasting is an elementary operation to support many applications. In [15], it is shown that naively broadcasting by flooding may cause serious redundancy, contention, and collision in the network, which we refer to as the broadcast storm problem. Several threshold-based schemes are shown to perform better than flooding in that work. However, how to choose thresholds also poses a dilemma between reachability and efficiency under different host densities. In this paper, we propose several adaptive schemes, which can dynamically adjust thresholds based on local connectivity information. Simulation results show that these adaptive schemes can offer better reachability as well as efficiency as compared to the results in [15].
Optimizing the packet forwarding throughput of multi-hop wireless chain networks
(2003-09-01)
Wang, SY
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資訊工程學系
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Department of Computer Science
In the literature, it has been shown that due to signal interferences between neighboring stations, the maximum packet forwarding throughput of a N-hop wireless chain network decreases as N increases and is only 1/N of the wireless bandwidth. This 1/N trend continues until the throughput finally stabilizes at only 1/5 or even less when N becomes large. To solve this problem, this paper proposes an approach that optimizes the forwarding throughput of a wireless chain network. In this approach, which we call the 'two-frequency scheme', the wireless interface cards of some nodes in the wireless chain network will swap their operating frequency channels between two different channels to avoid interferences. Using this approach, even when N is large, the forwarding throughput can be cost-effectively improved to 1/2, which is the optimal forwarding throughput that can be achieved by a half-duplex wireless interface. (C) 2003 Elsevier Science B.V. All rights reserved.

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