Jyh-Shyan Huang

Challenges of emergency communication network for disaster response

When stricken by a catastrophic natural disaster, the efficiency of disaster response operation is very critical to life saving. However, communication systems, including cellular networks, were usually crashed due to various causes making the coordination among a large number of disorganized disaster response workers extremely difficult. Survival rate can be greatly increased by breaking the communication bottleneck. Based on our firsthand experience in 921 Chi-Chi Earthquake and extensive research, we synthesize a set of requirements for deploying an emergency communication network for disaster response (ECN-DR), which can be deployed and operated under extreme environment and unusually communication behaviors in disaster areas. There are seven challenges, called 7-ability, that have to be addressed when designing an ECN-DR. 7-ability includes popularity, usability, practicability, capacity, reliability, operability and adaptability. Popularity and usability are used to fulfill end-user requirements. Practicability, capacity, reliability, operability and adaptability are used to fulfill operator requirements. Finally, we propose high level system architecture of ECN-DR. Several research issues about how 7-ability can be achieved will be presented.

Design of Contingency Cellular Network

When a catastrophic natural disaster occurs, the efficiency of disaster response operation is crucial to life saving. However, communication systems, such as cellular networks, were usually crashed due to various causes that made coordination difficult for many disorganized disaster response workers extremely. Unfortunately, rapid deployment of many existing emergency communication systems relies on a good transportation system, which is usually not available in a catastrophic natural disaster. We propose an emergency communication system, Contingency Cellular Network (CCN), by connecting disconnected base stations together with wireless links and portable power generators. CCN can support existing mobile phone users with limited capability. Such a system can support a large number of voluntary workers in the early hours of a catastrophic natural disaster, thus saving many lives. Design philosophy and high level system architecture of our framework are presented in this paper.

Design of multi-path network topology for contingency cellular network

When stricken by a large-scale disaster, the efficiency of disaster response operation is very critical to lifesaving. However, communication systems, such as cellular networks, usually crashed due to various causes making coordination among disorganized disaster responders extremely difficult. Unfortunately, rapid deployment of many existing emergency communication systems relies on a good transportation system, which is usually not available in a catastrophic natural disaster. We propose a Contingency Cellular Network (CCN) for emergency communication by connecting disconnected base stations together using wireless links to construct a multi-hop contingency cellular network. CCN can support existing mobile phone users with reduced capability. Such a system can support a large number of disaster responders and victims in the early hours of a catastrophic natural disaster, thus save many lives. The paper addresses the multi-path network topology design problem of CCN. In which, selected nodes will have multiple path to reach the core network, and thus, have higher resiliency against link failure. The problem is proven NP Hard. Therefore, we design an efficient heuristic algorithm (LBDK) to solve the problem when it is needed in urgent. Finally, we evaluated the proposed algorithms by simulation. A significant improvement in resiliency by using multi-path topology is reached.

Client location tracking in ubiquitous information service network

The objective of this paper is to present a feasible and efficient methodology that improves client mobility management under ubiquitous information service network. We base our system on the Open Integrated Service Network Architecture and propose a hybrid infrastructure with facilities of both a centralized Network Management Center (NMC) and a distributed Home Base Node (HEN). We also have criteria for choosing a HEN with minimum cost by computing the expected registration cost and location tracking cost according to users characteristics and called frequencies. Running a simulation, results show that our methodology is able to save up to 40% of the cost comparing to that of IS-41 when the value of Call-Mobility Ratio (CMR) is in the range of (1, 100), which means either clients are called with high frequencies or are moving with low mobilities. As the value of CMR goes down to the range of (0.01, 1), which means either clients are called with low-frequencies or are moving with high mobilities we may save up to 50% cost.

Resource delivery path dependent deployment scheduling for contingency cellular network

When a catastrophic natural disaster occurs, the efficiency of disaster response is crucial to life saving. However, mobile communication systems usually crashed due to various causes, making the coordination among a large number of disorganized disaster response workers extremely difficult. We propose a Contingency Cellular Network (CCN) by connecting disconnected base stations together with wireless links and portable power generators. Since the transportation capacity may be very limited, scheduling of CCN deployment order according to the demand of disaster response becomes an important issue. Two models aiming to maximize disaster response efficiency are proposed in this research. Emergency levels of disaster areas, time decreasing profit functions, traveling time of delivery path, and antecessor precedence constraint are taken into consideration in the CCNDS-AC model. The second model, CCNDS-UC is the same but with antecessor precedence constraint relaxed. Both problems are proven NP complete. Two heuristic but efficient algorithms are designed to solve the problems. Both algorithms can outperform our previous algorithm by a significant margin in our simulation experiments. This shows that the traveling time is a significant factor in designing an effective CCN deployment scheduling problem.

Cross Network Topology Design for Contingency Cellular Network

When stricken by a large-scale disaster, the efficiency of disaster response operation is very critical to lifesaving. However, communication systems, such as cellular networks, usually crashed due to various causes making coordination among disorganized disaster responders extremely difficult. Unfortunately, rapid deployment of many existing emergency communication systems relies on a good transportation system, which is usually not available in a catastrophic natural disaster. We proposed a Contingency Cellular Network (CCN) for emergency communication by connecting disconnected base stations together with wireless links and constructing a multi-hop cellular network. CCN can support existing mobile phone users with reduced capability. Such a system can support a large number of disaster responders in the early hours of a catastrophic natural disaster, thus save many lives. This paper addresses the design of forwarding topology using multiple operators base stations aiming to maximize the efficiency of disaster response. We take the degree of emergency and population of each stricken area as the priority measure as well as the available resources as the constraint to determine the topology. The CCN Cross Network Topology Design problem is modeled as a K-Maximum Spanning Tree Problem. The problem is proven NP Hard. We also designed a few efficient heuristic algorithms to solve the problem when it is needed in urgent.

A Flow-Aware Placement of Mobile Agent Control Network over Opportunistic Networks

Transmitting data on an opportunistic network is much more difficult than that on a conventional network. We propose to use mobile agent to enhance its message transfer efficiency. A mobile agent platform requires a search mechanism to control its agents. We investigated the application of mobile agent on the opportunistic network characterized by “CenWits Search and Rescue System” applied in YuShan National Park as well as proposed a control network technology to support rapid agent search. This paper enhances our previous control network placement models by taking into account the amount of agent flows. After proving it to be NP-hard, we designed a simple but efficient heuristic algorithms to solve the placement problem. In our simulation study, the new model outperforms our previous models easily.