Yung-Fa Huang

A stable weight-based on-demand routing protocol for mobile ad hoc networks

A mobile ad hoc network (MANET) consists of a set of mobile hosts that can communicate with each other without the assistance of base stations. In MANETs, the high mobility of mobile nodes is a major reason for link failures. In this paper, we propose a stable weight-based on-demand routing protocol (SWORP) for MANETs. The proposed scheme uses the weight-based route strategy to select a stable route in order to enhance system performance. The weight of a route is decided by three factors: the route expiration time, the error count, and the hop count. Route discovery usually first finds multiple routes from the source node to the destination node. Then the path with the largest weight value for routing is selected. Simulation results show that the proposed SWORP outperforms DSR, AODV, and AODV-RFC, especially in a high mobility environment.

A suboptimal PTS algorithm based on particle swarm optimization technique for PAPR reduction in OFDM systems

A suboptimal partial transmit sequence (PTS) based on particle swarm optimization (PSO) algorithm is presented for the low computation complexity and the reduction of the peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) system. In general, PTS technique can improve the PAPR statistics of an OFDM system. However, it will come with an exhaustive search over all combinations of allowed phase weighting factors and the search complexity increasing exponentially with the number of subblocks. In this paper, we work around potentially computational intractability; the proposed PSO scheme exploits heuristics to search the optimal combination of phase factors with low complexity. Simulation results show that the new technique can effectively reduce the computation complexity and PAPR reduction.

A modified genetic algorithm PTS technique for PAPR reduction in OFDM systems

In this paper, we propose a peak-to-average power ratio (PAPR) reduction method for an orthogonal frequency division multiplexing (OFDM) system by combining the improved genetic algorithm used the partheno-crossover operator (PCGA) with partial transmit sequence (PTS) scheme, called PCGA-PTS. Recently, the genetic algorithm based PTS scheme (GA-PTS) is a novel PAPR reduction method, which has lower computational load than the PTS technique and is a suboptimal PAPR reduction method. However, how to further improve the PAPR performance of GA-PTS in OFDM systems is still an active research. Therefore, this paper proposes a new PAPR reduction method to improve the PAPR performance of GA-PTS, based on the same computational complexity. Our proposed method uses a two-step crossover operator and a mutation operator to generate the offspring, and then selects the proper candidates from the offspring to be the individuals of new population, where the two-step crossover operator is composed of a crossover operator and a partheno-crossover operator. In simulation results, our proposed method has better PAPR performance than the GA-PTS technique in OFDM systems.

Energy-Aware Data Aggregation for Grid-Based Wireless Sensor Networks with a Mobile Sink

Wireless sensor networks (WSNs) are made up of many small and highly sensitive nodes that have the ability to react quickly. In WSNs, sink mobility brings new challenges to large-scale sensor networks. Almost all of the energy-aware routing protocols that have been proposed for WSNs aim at optimizing network performance while relaying data to a stationary gateway (sink). However, through such contemporary protocols, mobility of the sink can make established routes unstable and non-optimal. The use of mobile sinks introduces a trade-off between the need for frequent rerouting to ensure optimal network operation and the desire to minimize the overhead of topology management. In this paper, in order to reduce energy consumption and minimize the overhead of rerouting frequency, we propose an energy-aware data aggregation scheme (EADA) for grid-based wireless sensor networks with a mobile sink. In the proposed scheme, each sensor node with location information and limited energy is considered. Our approach utilizes location information and selects a special gateway in each area of a grid responsible for forwarding messages. We restrict the flooding region to decrease the overhead for route decision by utilizing local information. We conducted simulations to show that the proposed routing scheme outperforms the coordination-based data dissemination scheme (CODE) (Xuan, H. L., & Lee, S. Proceedings of the Sensor Networks and Information Processing Conference, pp. 13–18, 2004).

An Isolation Intrusion Detection System for Hierarchical Wireless Sensor Networks

Normal 0 0 2 false false false MicrosoftInternetExplorer4 A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices using sensors to cooperatively monitor environmental conditions, such as battlefield data and personal health information, and some environment limited resources. T o avoid malicious damage is important while information is transmitted in wireless network. Thus, Wireless Intrusion Detection Systems are crucial to safe operation in wireless sensor networks. Wireless networks are subject to very different types of attacks compare to wired networks. In this paper, we propose an isolation table to detect intrusion by hierarchical wireless sensor networks and to estimate the effect of intrusion detection. The primary experiment proves that isolation table intrusion detection can prevent attacks effectively.

Peak-to-average power ratio reduction in orthogonal frequency division multiplexing system using differential evolution-based partial transmit sequences scheme

A differential evolution (DE)-based partial transmit sequence (PTS) scheme for peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems has been proposed. PTS techniques can improve the PAPR statistics of an OFDM signals, but the considerable computational complexity for the required search through a high-dimensional vector space is a potential problem for the implementation in practical systems. The DE is an efficient and powerful population-based stochastic search technique for solving optimisation problems over continuous space, which has been widely applied in many scientific and engineering fields. Thus, to reduce the complexity for searching phase weight vector and to improve the PAPR statistics, the authors introduce DE, to search the optimal phase weight factors. The simulation results show that the proposed DE-based PTS obtains an excellent PAPR performance with a low computational complexity.

A new method for intrusion detection on hierarchical wireless sensor networks

Wireless Sensor Network (WSN) is a novel technology in wireless field. The main function of this technology is to use sensor nodes to sense important information, just like battlefield data and personal health information, under the limited resources. It is important to avoid malicious damage while information transmits in wireless network. So Wireless Intrusion Detection System (WIDS) becomes one of important topics in wireless sensor networks. The attack behavior of wireless sensor nodes is different to wired attackers. In this paper, we will propose an isolation table to detect intrusion in hierarchical wireless sensor networks and to estimate the effect of intrusion detection effectively. The primary experiment proves the isolation table intrusion detection can prevent attacks effectively.

Development of a Portable Linux-Based ECG Measurement and Monitoring System

This work presents a portable Linux-based electrocardiogram (ECG) signals measurement and monitoring system. The proposed system consists of an ECG front end and an embedded Linux platform (ELP). The ECG front end digitizes 12-lead ECG signals acquired from electrodes and then delivers them to the ELP via a universal serial bus (USB) interface for storage, signal processing, and graphic display. The proposed system can be installed anywhere (e.g., offices, homes, healthcare centers and ambulances) to allow people to self-monitor their health conditions at any time. The proposed system also enables remote diagnosis via Internet. Additionally, the system has a 7-in. interactive TFT-LCD touch screen that enables users to execute various functions, such as scaling a single-lead or multiple-lead ECG waveforms. The effectiveness of the proposed system was verified by using a commercial 12-lead ECG signal simulator and in vivo experiments. In addition to its portability, the proposed system is license-free as Linux, an open-source code, is utilized during software development. The cost-effectiveness of the system significantly enhances its practical application for personal healthcare.

Lifetime performance of an energy efficient clustering algorithm for cluster-based wireless sensor networks

This paper proposes a fixed clustering algorithm (FCA) to improve energy efficiency for wireless sensor networks (WSNs). In order to reduce the consuming energy of sending data at each sensor, the proposed algorithm uniformly divides the sensing area into clusters where the cluster head is deployed in the center of the cluster area. Simulation results show that the proposed algorithm definitely reduces the energy consumption of the sensors and extends the lifetime of the networks nearly more 80% compared to the random clustering (RC).

Implementation of an RFID-based management system for operation room

Surgery-related error, second to drug-related error, is one of the most commonly found medical errors resulting in premature deaths of patients. Improvement of operation room (OR) environment through efficient OR management, surgical procedure check, personnel communication, and information transmission can highly elevate the patient safety. In this study, radio frequency identification (RFID) was used to enhance the OR management (ORM) information system for efficient identification of patients and healthcare providers, tracking of critical surgery procedures, and control of medications and medical materials to prevent medical errors. A prototypic system which composes of console, operation room, surgery room, and recovery room subsystems is presented. Preliminary clinical application was tested in the surgical department of a hospital near Taichung area. The result demonstrated that it is useful in preventing medical errors under surgical setting. Further evaluation of efficiency has to be done in the future.