Cheng-Ying Yang

A Novel Fall Prediction System on Smartphones

The elderly person’s life is almost full of hazards. Especially, the fall risk is one of the problems caused by the elderly and the people using prostheses. This paper aims to develop a fall prediction system on smartphones. The proposed App system can record users’ gait data sets with which their gait statuses regarding stability and symmetry are analyzed. A high-level fuzzy Petri net model is used to identify the human’s actions, including normal action, sport, and fall risk. The experimental results indicate that there are high successful predictions obtained by the proposed App system. Thus, it can easily increase the fall risk prevention.

A Secure End-to-End Mobile Chat Scheme

Currently, mobile communications are provided convenient methods to explore and communicate with each other people. A multitude of services have converged on the smartphone platform, and potentially the most notable is social networking. Thus, the electronic Mobile Chat (MC) plays a very important role in the social networking. With the increasingly growing reliance on Mobile Chat System (MCS) in one hand, and the growing number of vulnerabilities and attacks on the other hand, there is an increasingly demand for the security solutions. Despite of the critical role of MCS in the typical Internet mobile users life, electronic MC services are not so secure. Therefore, the secure End-to-End Mobile Chat (SE2E-MC) scheme is proposed to be one of the suitable solutions. The basic framework for SE2E-MC scheme and its associated requirements are also designed in this paper. The proposal is implemented to provide mutual authentication and prevent the password guessing attack and the undetectable on-line password guessing attack. Finally, the scheme is a password-based authentication and key agreement (AKA) having easy remembered property.

Downlink Relay Selection Algorithm for Amplify-and-Forward Cooperative Communication Systems

In wireless networks, the cooperative relaying that provides a spatial diversity and improves the performance of system is a tendency in the future communications. There are three strategies in the cooperative communications. One is Amplify-and-Forward (AF) mode. Another is Decode-and-Forward (DF) mode and the other is Compress and Forward (CF) mode. Comparing with these three kind modes, AF mode is with the low complexity to implement. Consider the Raleigh fading environment where there are one information source, M relay stations and N destinations. The downlink signal includes two parts. One is from the source and the other comes from the relay stations. In order to achieve the maximum throughput in the system, it should obtain the maximum mutual information between the source and the destination. Hence, how to select an optimal relay station is important in the cooperative communications. This project proposes a relay selection algorithm with Amplify-and-Forward mode employed. The optimal selection scheme is based on the exhaustive search method. It is easy to be realized with a high computational complexity. In order to reduce the computational complexity, the relay station selection scheme with a maximum mutual information finding is proposed. With different relay station selection schemes, the performances are given for comparison.

Analysis of the problem description in the Algorithm for Inventive Problem Solving using Petri nets

The Theory of Inventive Problem Solving (TRIZ) has been widely employed in the fields of business and industry. The degree of difficulty in a problem usually depends on its description and degree of standardization. Using an appropriate description and maintaining standardization can minimize the scope of the problem and significantly increase the likelihood of resolving it successfully. Most problems can be resolved easily with innovative principles and standard resolutions. However, non-standard complex invention problems must be analyzed and resolved using the Algorithm for Inventive-Problem Solving (ARIZ), which contains numerous systematic tools of the TRIZ. This study applies the behavioral properties of a Petri net to the description of a problem to establish a problem model and perform scenario analysis. When describing the problem, the developer was provided with suitable directions of thinking or with wrong messages for reference. To create more specific effects on the varied problem models and scenario analyses of the TRIZ, this study combines the TRIZ with Petri nets and Markov chains to help new learners of TRIZ or professional researchers obtain appropriate resolutions rapidly.

Localization scheme based on multistatic radar systems

A weighted least square (WLS) scheme to estimate the target location in the TRM multistatic radar system based on the modified TOA measurements is proposed. The performance of the location estimation scheme is evaluated according to the basis of the root mean square error (RMSE). In the proposed scheme, all the measured errors including the measured azimuth angle, the measured elevation angle, and the measured range from the sum of the distance for transmitter-to-target and the distance for target-to-receiver are considered. The performance of the proposed scheme is given under the cases of the bistatic radar system and the TR4 multistatic radar system, respectively. According to the simulation results, the performance could be improved with the increasing of the number of receivers in the system.

Verification of problem-based learning systems using modified petri nets

In this paper, we intend to verify a web-based system on problem-based learning (PBL). To consider the design flow of the web-based PBL system, it is essential to avoid the potential hazard introduced by a logically incorrect system design. In order to eliminate the potential hazard, we define a new class of Petri net, namely, an Activity Flow (AF) net, which is suitable to be converted from a UML (Unified Modeling Language) activity diagram. Through the siphon-based deadlock detection of the AF net, we can find whether there is a process hazard in the UML activity diagram or not. This is helpful to implement the PBL system and to ensure the correct activities and the right control flow. In addition, we attempt to enhance the quality of the system verification by using a questionnaire. Thus we can interpret the users level of satisfaction with the designed PBL system. These two verification approaches bring us to achieve an adequately positive response to the web-based PBL system.

A Blind Data Hiding Technique with Error Correction Abilities and a High Embedding Payload

Least significant bit (LSB) embedding is a simple steganographic technique used in the spatial domain that involvesreplacing the LSB of each pixel in the cover work with the information bits being hidden to achieve informationsecrecy. However, considering the current prevalence of information theft and sabotage, the stego image producedusing LSB embedding cannot prevent malicious illegal acts. Therefore, this study proposes a blind data hidingtechnique that combines block-coded modulation (BCM) codes with LSB embedding. The proposed method not onlyprovides error correction capabilities to prevent errors during the extraction process, but also has a superiorembedding payload. The peak signal noise ratio (PSNR) exceeds 40 dB by using our proposed method. Regardingthe simulation results, the proposed method provides a superior PSNR compared to LSB embedding and a higherembedding payload than that offered by other steganographic techniques with error correction capabilities.

An Improvement of Tseng–Wu Group Key Exchange Protocol

Based on the group Diffie–Hellman technique, a contributory group key exchange protocol has been proposed by Biswas. Although Biswas claimed the protocol belongs to a contributory group key exchange, Tseng and Wu did not agree with. Then, they proposed an improved group key exchange protocol with a character of verifiably contributory and claimed the proposed protocol could not provide a secure scheme against passive attacks. However, Ling et al. pointed out that it is vulnerable to a man-in-the-middle attack with Tseng–Wu’s protocol. The attackers could intercept and modify the messages among the group members. In this article, we will propose an improvement of Tseng–Wu group key exchange protocol. Our protocol could against remedy the man-in-the-middle attack.

An Improved Hou-Wang’s User Authentication Scheme

It’s easy to access Internet resources in the cloud environment. And it’s important to protect the legal users’ privacy and confidentiality. Recently, Hou and Wang proposed a robust and efficient user authentication scheme based on elliptic curve cryptosystem. Their scheme was practical and easy to implement. They claimed that their scheme could against off-line password guessing, DoS, server spoofing, replay, parallel session and impersonation attacks. In this article, we will show that Hou-Wang’s scheme is vulnerable to the guessing attack with smart card. In this article, we also propose an improved Hou-Wang’s user authentication scheme to withstand the vulnerability in their scheme.

Secrecy Analysis in the AF Mode Cooperative Communication System

Cooperative system is a tendency for the future communications because of its spatial diversity to improve the system performance. However, the security is a critical issue in the wireless application with a highly private request. Although the encryption schemes have been proposed to approach the secure purpose, those schemes need a lot of computing resource. It is not practical for the applications with a limited computing ability, such as IoT. According to Shannon theory of perfect secrecy, the security could be implemented on the physical layer. Based on the positive secrecy rate, the secure communication could be practical. This work concentrates on the theoretical solution to the secrecy rate in the AF mode cooperative communication system. Also, the numerical results are given. It shows the effects of eavesdropper could not affect the secure communication if the number of the eavesdropper is less than that of relays in the system. The appropriate relay assignment benefits the secure communication.