Sheng-Chang Chen

A study of recent research trends and experimental guidelines in mobile ad-hoc network

This work investigates and analyzes recent research trends and presents experimental guidelines on MANETs. More than 1,300 MANET related papers in IEEE/IEE Electronic Library (IEL Online) from 1998 to 2003 were collected and surveyed. The research trends, qualitative analysis and simulation guidelines from fifteen major MANET issues are investigated to assist the user in conducting MANET research. Based on recent six year trends we found that some issues such as routing and power management attracted much attention. We also found that some issues have potential study value, such as IP addressing and fault tolerance. In the qualitative analysis, we found that some factors such as scalability, stability, and reliability attracted much attention in major MANET issues. The essential simulation metrics for various MANET issues are identified and listed for experimental guidelines. The analysis results demonstrate the utilization trends for various MANET simulators.

HarpiaGrid: A Geography-Aware Grid-based Routing Protocol for Vehicular Ad Hoc Networks

Vehicular Ad Hoc Network (VANET) is a research field attracting growing attention. Current routing protocols in VANETs usually use route discovery to forward data packets to the destination. In addition, if vehicle density is low in the network, there might not be vehicles available to deliver the packet. This paper proposes HarpiaGrid, a geography-aware grid-based routing protocol for VANETs. The protocol uses map data to generate a shortest transmission grid route, effectively trades route discovery communication overhead with insignificant computation time. By restricting packets in grid sequences rather than blindly greedy search and making use of route cache approach, HarpiaGrid reduces many unnecessary transmissions, thus greatly improving routing efficiency. Moreover, in the route maintenance, this work proposes a local recovery scheme and uses backtracking techniques to generate a new grid forwarding route, providing superior fault-tolerance capability. Experiments were conducted, and the results demonstrated that the proposed scheme is indeed more efficient than other protocols.

A Scalable and Reliable Multicast Routing Protocol for Ad-hoc Wireless Networks

Multicasting is an essential service for ad-hoc wireless networks. In a multicasting environment with multiple senders, receivers or meeting members, traditional multicast routing protocols must pay great overhead for multiple multicast sessions. This work presents a scalable and reliable multicasting protocol for ad-hoc wireless networks. A virtual backbone is used as a shared structure for multiple sessions. A clustering scheme is used to reduce the routing path length. A novel scheme is developed to effectively multicast packets using forwarding gates. Furthermore, a lost packet recovery scheme is developed for reliable packet transmission. This scheme can be used to improve the reliability of traditional non-acknowledged multicasting approach. Experiments were conducted to evaluate the proposed multicasting scheme and the results demonstrate that our scheme outperforms other schemes in terms of packet delivery ratio, packet delivery time, control overhead, multicast efficiency, and cost effect. Furthermore, our approach is stable for networks with high mobility and the lost packet recovery scheme is cost-effective.

An Implementation of Augmented Reality and Location Awareness Services in Mobile Devices

The popularization of smartphones and advances in location-based technology have led to the creation of many applications and diverse mobile cloud technologies. Augmented reality (AR), which integrates virtual reality with the real world, is one of the mobile service technologies that have been receiving considerable attention in recent years. This study focuses on AR technology, which in conjunction with point of interest (POI) information

A Reliable Multicast Routing Protocol Based on Recovery Points in Mobile Ad-HOC Networks

Multicasting is an essential service for mobile ad-hoc networks. A major challenge of multicasting in mobile ad-hoc networks is unstable forwarding path. This work presents a reliable multicasting protocol for mobile ad-hoc networks. A virtual backbone is used as a shared structure for multiple sessions, and a lost packet recovery scheme is developed for reliable packet transmission, called recovery point (RP) scheme. The RP scheme keeps the data packets from the source for recovering lost packets for its downstream RPs. A mergence scheme for RP is proposed to avoid the excessive control overhead. This scheme can be used to improve reliability of the traditional non-acknowledged multicasting approach. Experiments were conducted to evaluate the proposed multicasting scheme and the results demonstrate that our scheme outperforms other schemes in terms of packet delivery ratio and multicast efficiency. Furthermore, the simulation results also demonstrate that our approach is stable in networks with high mobility

An efficient anycast scheme for discovering K services in mobile ad-hoc networks

This work proposes an efficient anycast scheme, called AnyKast, for discovering k services in cluster-based mobile ad-hoc networks. In the AnyKast scheme, an anycast tree based on the clustering and virtual backbone is established to reduce unnecessary message transmission. In the anycast tree, anycast clusterheads disseminate their information to certain specific nodes that take the service information and perform the service selection task instead of blindly searching. Furthermore, to decrease the cost of service information collection and maintenance, scope flooding is used to limit the information transmission, and information piggybacking and periodical inquiry mechanism are used to increase the service information accuracy. The experimental results demonstrate that our scheme can effectively discover services, reduce request and reply message control overhead and lower the searching latency.

A Virtual Laboratory for Macro Universities Using Mobile Agent Techniques

This work designs, develops and implements a virtual laboratory for digital circuit design in Macro Universities that can create a rich learning environment for students from all over the world. Our system consists of four parts: agent execution environments, mobile agents, wrapper agents and experimental platforms. Mobile agents are received and executed in the agent execution environment, which provides locations and other resources for the mobile agents. The wrapper agent acts as a middleware for the mobile agent and the experimental platform. The experimental platform is an existing application program that could be a learning program, such as a CAI tool or a design tool, such as a CAD system. The major merit of our system is that it enables network capability for a standalone program without the need for the source code of the original program. The prototype of our virtual laboratory is targeted at a digital circuit laboratory. Experimental results demonstrate the feasibility of our approach.

Recent developments and experimental guidelines in mobile ad-hoc networks

The Mobile Ad-hoc Network (MANET) is one of the most vibrant and active current research topics. This work investigates and analyses recent research trends and presents experimental guidelines on MANETs. More than 1900 MANET-related papers were collected and surveyed in IEEE/IEE Electronic Library (IEL Online) from 1998 to 2004. The research trends, qualitative analysis and simulation guidelines from 15 major MANET issues are investigated to assist the user in conducting MANET research. On the basis of recent seven-year trends, we found that some issues, such as routing, power management and bandwidth management, have attracted much attention. We also found that some issues have potential study values, such as radio interface and security. In the qualitative analysis, we found that some factors such as scalability, stability and reliability attracted much attention in major MANET issues. The essential simulation metrics for various MANET issues are identified and listed for experimental guidelines. The analysis results also demonstrate the utilisation trends for various MANET simulators.

A Reliable Multicast Routing Protocol Based on Recovery Points and FEC in Mobile Ad-hoc Networks

Multicasting is an essential service for mobile ad-hoc networks. A major challenge for multicasting in mobile ad-hoc networks (MANETs) is the unstable forwarding path. This work presents a reliable multicasting protocol for mobile ad-hoc networks. A virtual backbone is used as a shared structure for multiple sessions. A lost packet recovery scheme is developed for reliable packet transmission, called the Recovery Point (RP) scheme. The RP scheme maintains the data packets received from the source for recovering lost packets for its downstream RPs. In addition, we combine the Forward Error Correction (FEC) technology with our RP scheme to enhance the reliability of our RP scheme. A mergence scheme for RP is also proposed to avoid excessive control overhead. Our RP and FEC based scheme can be used to improve the reliability and efficiency of the traditional non-acknowledged multicasting approach. Experiments were conducted to evaluate the proposed multicasting scheme. The results demonstrate that our scheme outperforms other schemes in terms of packet delivery ratio and multicast efficiency. Furthermore, the simulation results also demonstrate that our approach is stable in networks with high mobility.

An efficient anycast scheme for discovering k services in cluster-based mobile ad hoc networks

Anycast is a one-to-any bidirectional transmission scheme that can be used to provide various service-oriented applications. However, traditional anycast cannot support some distributed applications that need to locate multiple servers such as network time protocols and threshold cryptography. Although there are some extended anycast schemes that can support the discovery of k services, they may cause high control overhead, low satisfaction ratio, or high searching latency when there are more service requesters and providers. The main reasons for these shortcomings are unknown service information and limited hierarchical structure. This work proposes an efficient anycast scheme, called AnyKast, for discovering k services in cluster-based mobile ad hoc networks. In the AnyKast scheme, an anycast tree based on the clustering and virtual backbone is established to reduce unnecessary message transmission. In the anycast tree, anycast clusterheads disseminate their information to certain specific nodes that take the service information and perform the service selection task instead of blindly searching. Furthermore, to decrease the cost of service information collection and maintenance, scope flooding is used to limit the information transmission, and information piggybacking and periodical inquiry mechanism are used to increase the service information accuracy. The experimental results demonstrate that our scheme can effectively discover services, reduce request and reply message control overhead, and lower the searching latency. Copyright