Clustering schemes can reduce energy consumption, prolong network lifetime and improve scalability in wireless sensor networks (WSNs). In a typical cluster-based WSN, sensor nodes are organized into clusters. Each cluster elects a cluster head (CH) node. The CH is responsible for collecting the sensed data from cluster members, aggregating data and transmitting data to the sink node via a multi-hop path through intermediate CHs. Thus, the use of cluster techniques not only shortens the transmission distances for sensor nodes but also reduces energy consumption; however, each cluster imposes a larger load on the CH. Under this situation, CHs closer to the sink node tend to use up their batteries faster than those farther away from the sink node due to imbalanced traffics among CHs. To overcome this problem, we contribute to the energy balancing issues in WSNs from two aspects. In the first work, we first analyze the corona model. Based on analysis results, we found that nearly balanced energy consumption of WSNs can be achieved with the additional help of arranging different initial conditions. We then propose the Energy-balanced Node Deployment with Balanced Energy (END-BE) scheme and Energy-balanced Node Deployment with Maximum Life-Time (END-MLT) scheme, which determine the cluster density for each corona according to the energy consumption of each CH. Simulation results show that energy consumption is nearly balanced by implementing END-BE, and the network lifetime is greatly improved by adopting END-MLT. In the second work, we development a novel cluster-based routing protocol for corona-structured wireless sensor networks in order to balance the energy consumption among CHs. Based on the relaying traffic of each CH conveys, adequate radius for each corona can be determined through nearly balanced energy depletion analysis, which leads to balanced energy consumption among CHs. Simulation results demonstrate that our clustering approach effectively improves the network lifetime, residual energy and reduces the number of CH rotations in comparison with the Multi-Layer Clustering Routing Algorithm (MLCRA).

Due to the rapid development of the Internet and the fast expansion of the bandwidth, the requirement of the real-time service for the Internet is necessary. In this way, the problem of the real-time service for the Internet becomes an important issue. Most of the applications still use TCP as the protocol, but due to the reliable property of TCP, TCP can¡¦t fit the requirement of the real-time transfer. So, we need to implement a protocol which we can use on the real-time transfer service. According to the requirement, we find an open source application layer protocol ¡V UDT (UDP-based Data Transfer). We can implement the application of real-time transfer by using the partial reliable messaging property of the protocol. In addition, user can adjust the parameters or settings of the protocol to make their application get into better performance by using the composable property of the protocol. In our research, we¡¦ll compare with RTP (Real-time Transport Protocol) and UDT, and also explain the reason why we don¡¦t choose RTP in our research. The assumption environment of our research is financial real-time service, and the protocol of such applications is TCP. In this way, we¡¦ll analyze and compare the result of the tests between TCP and UDT. We¡¦ll also adjust the parameters of the protocol to test the performance of the UDT under the environment of the real-time transfer, such as data lose rate, etc.. These results can supply the reference for the users when using UDT as their protocol to implement their real-time applications.

In an attempt to slow the exhaustion of the Internet Protocol (IP) address space, Class-less Inter-Domain Routing (CIDR) was proposed and adopted. However, the decision to utilize CIDR also increases the size of the routing table, since it allows an arbitrary partitioning of the routing space. We propose a scheme to reduce the size of routing table in the CIDR context. Our approach utilizes a well-known and highly efficient heuristic to perform 2-level logic minimization in order to compress the routing table. By considering the IP routing table as a set of completely specified logic functions, we demonstrate that our technique can achieve about 25% reduction in the size of IP routing tables, while ensuring that our approach can handle routing table updates in real-time. The resulting routing table can be used with existing routers without needing any change in architecture. However, by realizing the IP routing table as proposed in this thesis, the implementation requires less complex hardware than Ternary CAM (TCAM) which are traditionally used to implement IP routing tables. The proposed architecture also reduces lookup latency by about 46%, hardware area by 9% and power consumed by 15% in contrast to a TCAM based implementation.

Two trials were conducted to quantify the effects of GnRH and prostaglandin in conjunction with a 7-d CIDR on estrus and on pregnancy rate in comparison with a traditional synchronization protocol. In trial 1, ewes (n=12) were randomly allotted to one of three treatments: CIDR (7 d) with administration of GnRH (Cystorelin®, 50μg, im) at CIDR insertion and PGF2α (Lutalyse®, 20 mg, im) on d 6.5 (GnRH1); the GnRH1 protocol with a second injection of GnRH 30 h after CIDR removal (GnRH2); and CIDR (11 d) with administration of PGF2α at CIDR insertion and PMSG (400 iu) at CIDR removal (PMSG). A blood sample was obtained every 2 h for 42 h after CIDR removal for serum LH analysis. On d 8 after CIDR removal, blood samples were obtained at 12 h intervals for 36 h for serum P4 analysis. One ewe in the GnRH1 group did not retain the CIDR device and was excluded from the analysis. Mean LH concentration did not differ (P = 0.48) among groups. Time and time x treatment affected (P < 0.001) mean LH concentration. Mean P4 concentration was not affected (P = 0.26) by time, treatment or their interaction. In trial 2, ewes (n=72) were randomly allotted to one of the three treatments described in trial 1. At CIDR removal, three ewes per treatment were joined with a single ram fitted with a marking harness in each of 8 pens. Ewes were monitored every hour for estrus activity and ultrasounded transabdominally 60 d after CIDR removal for pregnancy. Estrus activity did not differ (P > 0.05) among the groups. Marking frequency was 92 percent, 75 percent, and 88 percent for GnRH1, GnRH2, and PMSG groups, respectively. Mean interval to estrus was shorter (P < 0.05) for the GnRH2 than for the PMSG group and tended to be reduced (P < 0.10) compared with the GnRH1 group. Pregnancy rate differed (P < 0.05) among treatments (79 percent, 58 percent and 38 percent for GnRH1, GnRH2, and PMSG groups, respectively). These results indicate that synchrony of estrus and pregnancy rate to natural service can be increased in response to a CIDR protocol when combined with administration of GnRH rather than PMSG.

We propose a novel multicast routing protocol, called adaptive multicast routing protocol for MANETs (Mobile ad hoc routing protocol). Multicast routing protocols can be classified two types according the structure used to establish route. Existing protocols are either tree-based or mesh-based. In mesh-based routing protocols, a reliable protocol ODMRP was proposed. In ODMRP, each sender has to broadcast control packet periodically in order to build mesh. But with an increase of number of senders, control overhead causes reliability reduced because of a large amount of overhead and collisions. Hence, ODMRP is not work well in this case. We proposed our scheme to aim at the drawback of ODMRP. We use packet delivery ratio (PDR) to determine if the load of network is congestion. When packet delivery ratio is high, it means that the network traffic load is low, and vice versa. We determine whether a sender broadcasts Join-Query control packet or not according to packet delivery ratio. As packet delivery ratio is decrease, a sender does not broadcast Join-Query as far as it can in order to avoid collisions. However the packet delivery ratio is increase, senders have strong probability to broadcast Join-Query to establish mesh nodes. We can improve reliability and reduce overhead is caused by control packets with this way.

Because Ministry of Transportation and Communication want to improve its service quality and increase its revenue, Unite Communication Technology Ltd. (UCT) bring up ¡§BOT of E-Commerce and Wireless Internet¡¨ to built up the service of wireless internet and e-commerce on the train and in the station. Under the project, this thesis address to operate the value-added service of VOIP business with wireless internet to boost the total return ratio. According to data collection and survey, the financial model was erected to evaluate the feasible of this new business model. To sum up the result, the NPV of the project is 50,227,238 in 19 years (the discount rate equal to 6.49), IRR reach to 23.93%, and payback period is 7.415 years. Although the payback period is long, in terms of sustained and stable profit in the future, the project is still valuable. Furthermore, UCT is a telecommunication company so that the project can use the bandwidth more efficiently to maximum the corporation revenue. Keywords¡GWireless Internet, Voice on Internet Protocol (VOIP), Financial Feasibility Analysis

No description available.

Mobile ad hoc network is an architecture which do not exist any infrastructure or centralized administration. There are many routing protocols have been proposed so far, such as AODV, DSR and CGSR. These protocols were classified as reactive in which routes are established only when required. Due to the movement of mobile nodes, network topology changes frequently, and the routing path could be broken easily. This phenomenon will cause higher routing overhead and delivery latency. In conventional routing protocols, the source-destination pair only establishes a single path for data transmission. These routing scheme, however, suffer from the drawback of node movement. When route broken, the source node must reconstruct another new path. This paper presents an adaptive routing protocol named Adaptive Route Selection Scheme of Multiple Paths for Mobile Ad Hoc Network (ARSMA). The aim of the work is to improve the delivery ratio. In the route request phase, source nodes will discovery two routes to the destination node, one for primary path, and the other for the backup path. During the discovery procedure, each node will estimate the link expire time through the movement speed and direction of the precursor node. When a link breakage is about to occur, source node will try to switch the transmission to the backup route.The simulation result shows that ARSMA is able to achieve a remarkable improvement in delivery ratio and end-to-end dealy.

With fast and prosperous development in communication technology, desktop or mobile devices may be equipped with wired and wireless network interfaces. Hence, users need a multihoming technique to help them making use of the network in- terfaces effectively. The Stream Control Transmission Protocol (SCTP) is a new transport protocol approved by the SIGTRAN Working Group of IETF (Internet Engineering Task Force) as RFC 2960 in October 2000 where it includes this useful characteristic. However, this feature may lead to some secure pitfalls. In this thesis, we come up with some approaches to improve SCTP against some existing tough problems raised from multihoming and provide more sufficient protection methods based on cryptography. Finally, a comparison of the existing security solutions is also given to demonstrate our contributions.

<p>The wish to measure different environmental parameters, in for example office buildings, is getting more and more important in today’s society. Since the sensors should be easily deployed they need to be battery powered and communicate wireless. Furthermore the radio range must be extended because of the limited range on the free frequencies. This is where wireless sensor networks come in and extend the range by relaying the data through other nodes in the network, thereby extending the total range of the network.</p><p>The purpose of this thesis work is to develop a protocol for such a wireless sensor network, capable of delivering and relaying sensor data through the nodes of the network.</p><p>The protocol has been implemented in hardware also designed in this thesis. Tests of the network have been performed and the results have shown that the network works very well and fulfills all of the requirements. Furthermore the power consumption is only 15% of the required value. This thesis has produced a very good platform to use as a base for further development of a commercial product.</p>