Mao-Lun Chiang

A Privacy Authentication Scheme Based on Cloud for Medical Environment

With the rapid development of the information technology, the health care technologies already became matured. Such as electronic medical records that can be easily stored. However, how to get medical resources more convenient is currently concerning issue. In spite of many literatures discussed about medical systems, these literatures should face many security challenges. The most important issue is patients’ privacy. Therefore, we propose a privacy authentication scheme based on cloud environment. In our scheme, we use mobile device’s characteristics, allowing peoples to use medical resources on the cloud environment to find medical advice conveniently. The digital signature is used to ensure the security of the medical information that is certified by the medical department in our proposed scheme.

A fuzzy-based Power-aware management for mobile ad hoc networks

In recent years, people have become more dependent on wireless network services to obtain the latest information at any time anywhere. Wireless networks must effectively allow several types of mobile devices send data to one another. The Mobile Ad Hoc Network (MANET) is one important type of non-infrastructure mobile network that consists of many mobile hosts, usually cellular phones. The power consumption rate and bandwidth of each mobile host device becomes an important issue and needs to be addressed. For increasing the reliability of the manager in Hierarchical Cellular Based Management (HCBM), this paper proposed a Power-aware protocol to select a stable manager from mobile hosts by fuzzy based inference systems based on the factors of speed, battery power, and location. Further, our protocol can trigger a mobile agent to distribute the managerial workload.

Streets of consensus under unknown unreliable network

Generally, tasks in a distributed system, such as two-phase commitment in database system, the location of a replicated file, and a landing task controlled by a flight path finding system, must reach an agreement. This type of unanimity problems is called the agreement problem and one of the most fundamental problems in the field of distributed environment. It requires a set of the processors to agree on a common value even if some components of the system are corrupted. There are many significant studies about these problems in a regularized network environment such as Fully Connected Network, BroadCast Network, and MultiCast Network. Nevertheless, it is computationally infeasible to ignore the network structure in a real environment. In general, the network topology varies with time. Thus, this kind of uncertain network will generate unknown network environment and affect the system to reach a common value. In this paper, the agreement problem will be revisited in an Unknown Network. Simultaneously, Back Propagation Network (BPN) is used to help system to recognize the network structure. Subsequently, the proposed protocol, Unknown Network Protocol (UNP) can reach an agreement that uses the minimum rounds of message exchange and can tolerate the maximum number of faulty components.

An early fault diagnosis agreement under hybrid fault model

Reliability is an important research topic in distributed systems. To achieve suitable reliability, the fault tolerance of distributed systems must be studied. One of the most important issues surrounding fault tolerance is the Byzantine Agreement (BA) problem. The goal of BA is to achieve a common agreement among fault-free processors even where faults persist. Likewise, fault diagnosis agreement (FDA) the purpose of which is to cause each fault-free processor to detect/locate a common set of faulty processors should be considered. In general, the FDA protocols need @?(n-1)/3@?+2 rounds of message exchange to detect/locate the faulty components even if the small of number of faulty processors exists. The number of messages results in a large protocol overhead. In this study, the FDA problem is solved early by an evidence-based fault diagnosis protocol that uses the minimum number of rounds characterized by dual failure of processors. In addition, the proposed protocol can detect/locate the maximum number of faulty processors in a network.

A Simple Keystroke Dynamics-Based Authentication System Using Means and Standard Deviations

This paper investigates the practicality of a system utilizing the proportionality method to produce more suitable patterns in keystroke dynamics-based authentication systems. Three features are used in this system: digraph duration, keystroke latency, and keystroke duration. This system using the statistical measures of means and standard deviations with the proportionality method achieves a result of 0.0052 FAR and 0.0782 FRR in contrast to the system not using the proportionality method, which yields a result of 0.0118 FAR and 0.0813 FRR. The result serves as evidence that the proportionality method can be used to produce the critical patterns and also be applied to all related keystroke dynamics-based authentication systems to provide higher accuracy.

A new solution for the Byzantine agreement problem

Abstract Reliability is an important research topic in distributed computing systems consisting of a large number of processors. To achieve reliability, the fault-tolerance scheme of the distributed computing system must be revised. This kind of problem is known as a Byzantine agreement (BA) problem. It requires all fault-free processors to agree on a common value, even if some components are corrupt. Consequently, there have been significant studies of this agreement problem in distributed systems. However, the traditional BA protocols focus on running ⌊ ( n − 1 ) / 3 ⌋ + 1 rounds of message exchange continuously to make each fault-free processor reach an agreement. In other words, since having a large number of messages results in a large protocol overhead, those protocols are inefficient and unreasonable, especially for some network environments which have large number of processors. In this study, we propose a novel and efficient protocol to reduce the number of messages. Our protocol can collect, compare and replace the received values to find the reliable processors and replace the values sent by the unreliable processors. Subsequently, each processor can agree on a common value through three rounds of message exchange. Furthermore, the proposed protocol can use the minimum number of messages to tolerate the maximum number of faulty components in a distributed system.

Performance enhancement of WiMAX by three layers topology

Worldwide interoperability for Microwave Access (WiMAX) is a telecommunications protocol that provides fixed and mobile internet access. In addition, WiMAX can provide mobile wireless broadband access without the requirement for direct line-of-sight with a base station. In contrast with other wireless networks, WiMAX can provide high broadband speed, large coverage area, multiple bands and support for multimedia. However, a serious problem, the broadcast storm, needs to be addressed due in part to excessive communications from mobile devices, such as file, audio and video sharing. Therefore, a three-layer-based WiMAX network topology is proposed to reduce packet collisions and to enhance performance of communication efficiently. Furthermore, the stability and expansibility of the WiMAX topology can be improved.

The anatomy study of consensus agreement in MANETs

Reliability is an important research topic of distributed systems. To achieve fault-tolerance in the distributed systems, healthy processors need to reach a common agreement before performing certain special tasks, even if faults exist in many circumstances. This problem is called as the Byzantine Agreement (BA) problem and it must be addressed. In general, the traditional BA problem is solved in well-defined networks. However, the MANETs (Mobile Ad-hoc Network) are increasing in popularity and its network topology is dynamic in nature. In this paper, the BA problem is re-examined in MANETs. Our protocol uses the minimum number of message exchanges to reach an agreement within the distributed system while tolerating the maximum number of faulty processors in MANETs.

The incremental agreement

To achieve reliable distributed systems, the fault-tolerance must be studied. One of the most important problems of fault-tolerance issues lies in the Byzantine Agreement (BA) problem. The primary issue surrounding BA is that fault-free processors must obtain common agreement even in cases where faults persist. In this field, the fault diagnosis protocol has been proposed so that each fault-free processor detects/locates a common set of faulty processors. However, in this study, the incremental agreement is invoked to make each processor able to agreement upon executing the fault diagnosis protocol using minimal rounds of message exchange in the presence of dual failure characteristics of processors.

Work in progress: A new approach of changeable password for keystroke dynamics authentication system on smart phones

Most of subscribers use personal identification number (PIN) codes which combined with 6-8 numbers to protect their Subscriber Identity Module (SIM) cards from illegal accesses. To enhance security, many previous studies have employed keystroke dynamics to protect the PIN code, and the relative results exhibit that keystroke dynamics can indeed improve the security of a PIN code. However, the traditional keystroke dynamics-based authentication (KDA) system has to collect users keystroke dynamics firstly and then produce a unique personal biometrics. Its inconvenient for users when changing their PIN codes is required, because the corresponding KDA systems have to be retrained. To solve the above-mentioned drawbacks, this paper proposes a novel technique by which users can change their PIN codes anytime, without any extra retraining. Conducted experiment results show that the proposed approach can effectively improve the KDA system to distinguish legitimate users and impostors even when users change their original passwords.