Chung-wei Lee

Trust based adaptive on demand ad hoc routing protocol

In this paper, we propose a routing protocol that is based on securing the routing information from unauthorized users. Even though routing protocols of this category are already proposed, they are not efficient, in the sense that, they use the same kind of encryption algorithms (mostly high level) for every bit of routing information they pass from one intermediate node to another in the routing path. This consumes lot of energy/power as well as time. Our routing algorithm basically behaves depending upon the trust one node has on its neighbor. The trust factor and the level of security assigned to the information flow decide what level of encryption is applied to the current routing information at a source/intermediate node. In other words, above a certain level of trust level, there is no need for the source/intermediate node to perform high level encryption on the routing information as it completely trusts the neighboring node. So based on level of trust factor, the routing information will be low-level, medium level, high level encrypted, the low-level being normal AODV. This not only saves the nodes power by avoiding unnecessary encoding, but also in terms of time, which is very much valuable in cases of emergencies where the information is as valuable as the time.

A system model for mobile commerce

The emergence of wireless and mobile networks has made possible the introduction of electronic commerce to a new application and research subject: mobile commerce. Understanding or constructing a mobile commerce system is an arduous task because the system involves a wide variety of disciplines and technologies. To facilitate understanding and constructing such a system, this article divides a mobile commerce system into six components: (i) mobile commerce applications, (ii) mobile stations, (iii) mobile middleware, (iv) wireless networks, (v) wired networks, and (vi) host computers. Elements in components related to mobile commerce are described in detail and lists of technologies for component construction are also given.

Neighbor stability routing in MANETs

Mobile ad hoc networks (MANETs) are characterized by wireless connectivity through multi-hops, frequently changing network topology among wireless mobile devices. These characteristics require routing algorithms to be dynamic and adaptive to constantly changing environments. In this paper, we describe a new routing algorithm which is based on the cumulative relative stability among neighbor mobile nodes. This NSR (neighbor stability routing) algorithm selects the most historically and accumulatively stable mobile nodes to form a path between the source node and destination node. The relative stability is then propagated from the collective data by all the nodes along a path. The cumulative collective data, or stability factor, reflects the historical neighborhood stability among neighbors. When a node or segment on the path is down, NSR will dynamically find an alternative most stable path. In simulation, our NSR algorithm outperforms some major ad hoc routing protocols such as AODV and DSR in packet delivery ratio and number of paths rerouted. NSR also handles some issues such as group node mobility and temporary node unavailability well.

Multi-level secure video streaming over SRTP

In this paper, we propose a set of solutions to four different levels on data selection for encrypting Motion JPEG video frames over SRTP. These solutions are based on our intensive analysis of the JPEG image compression procedure. We select the most important data which contains most information of an image for encryption; in consequence provide a set of balances between security and computation for different hardware environments. Extensive experiments are conducted and performance data has been analyzed to evaluate the proposed solutions. Results show that these solutions are well suited in different scenarios with various computation power and security requirements.

Density-based multipath secure communication over mobile ad hoc networks

Security is a critical issue in mobile ad hoc networks (MANETs), where mobile nodes communicate with each other over relatively unreliable wireless links with no fixed infrastructure. One example of this occurs on battle fields, where soldiers often wear cameras and wireless mobile devices to send or receive images/video of different angles or locations in order to obtain better observation of the area. Such an environment could be highly insecure since an enemy could place devices to eavesdrop on or compromise the soldier nodes. In this paper, we consider a case where time sensitive multimedia is sent using multiple paths which can make better use of load balancing strategies, increase bandwidth and save node energy. However, an enemy node could listen in on more than one path at the same time, allowing it to collect sufficient shares of an image or video frame to recover the image. Our proposed algorithm is based on a quantitative analysis of security to protect against such multi-path eavesdropping. We prove that our algorithm can achieve better level of security by detouring traffic via paths without or with less vulnerable areas at the same amount of redundancy. On the other hand, we also prove, using simulation results and mathematical derivation, our algorithm can provide much more redundancy for better multimedia quality purpose while at the same time guaranteeing the same level of security.

Design and simulation of a supplemental protocol for BGP

Internet policy routing has attracted a lot of attention in the last decade and it is believed that this topic will become even more important in the foreseeable future. The growing diversity of the internet brings in many organizations under different authorities with conflicting interests. Each such organization forms an Autonomous System (AS), with its own policy regulating network traffic across its boundaries to protect valuable network resources. As a result, a policy violation at any intermediate AS may cause a packet to be silently dropped before reaching its destination. The Border Gateway Protocol (BGP) was introduced to solve this packet-dropping problem in the mid-1990s, followed by a series of revisions. Currently, BGP is the dominant protocol in this field. However, BGP is a distance-vector and hop-by-hop protocol, resulting in a loss of reachability information for some destinations, even though feasible routes to those destinations may physically exist. Unreachable destinations under BGP are not necessarily truly unreachable. To overcome this deficiency, this paper presents a source policy route discovery protocol to supplement BGP. Simulation results show that almost all the false negative unreachable destinations can be resolved by the proposed protocol.

Gene intrusion on a society of Hill-Climbers

In this paper, a new algorithm of Gene Intrusion on a Society of Hill-Climbers (GI-SoHC) is introduced. In GI-SoHC, the genes which contribute most to the best fitness of the best climber in each generation are selected and inserted to other climbers for replacing their own genes, such that the society can have faster climbing speed and better climbing locations.The experiment results show that with Gene Intrusion, climbers generally and averagely perform better in that they climb more quickly than the original Historical Society of Hill-Climbers, especially in the early stage of the climbing process.