• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.5
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• pp.1014-1035
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• 2013

With recent advances in wireless communication and low-power miniaturized biomedical sensor and semiconductor technologies, wireless body area networks (WBAN) has become an integral part of the disaster aid system. Wearable vital sign sensors can track patients' status and location, thus enhancing disaster rescue efficiency. In the past few years, most of the literatures in the area of disaster aid system based on WBAN have focused on issues concerning wireless sensor design, sensor miniaturization, energy efficiency and communication protocols. In this paper, we will give an overview of disaster aid, discuss about the types of network communication as well as outline related issues. We will emphasize on analyzing six key issues in employing the disaster aid system. Finally, we will also highlight some of the challenges that still need to be addressed in the future in order to help the disaster aid system be truly and widely accepted by the public.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.153-158
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• 2016

Broadcasting in multi-hop wireless sensor networks is a basic operation that supports many applications such as route search, setting up addresses and sending messages from the sink to sensor nodes. The broadcasting using flooding causes problems that can be mentioned as a broadcasting storm such as redundancy, contention and collision. A variety of broadcasting schemes using wireless sensor networks have been proposed to achieve superior performance rather than simple flooding scheme. Broadcasting algorithms in wireless sensor networks can be classified into six subcategories: flooding scheme, probabilistic scheme, counter-based scheme, distance-based scheme, location-based schemes, and neighbor knowledge-based scheme. This study analyzes a simple flooding scheme, probabilistic scheme, counter-based scheme, distance-based scheme, and neighbor knowledge-based scheme, and compares the performance and efficiency of each scheme through network simulation.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1836-1842
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• 2015

On road networks, the clustering of moving objects is important for traffic monitoring and routes recommendation. The existing schemes find out density route by considering the number of vehicles in a road segment. Since they don’t consider the features of each road segment such as width, length, and directions in a road network, the results are not correct in some real road networks. To overcome such problems, we propose a clustering method for congested routes discovering from the trajectories of moving objects on road networks. The proposed scheme can be divided into three steps. First, it divides each road network into segments with different width, length, and directions. Second, the congested road segments are detected through analyzing the trajectories of moving objects on the road network. The saturation degree of each road segment and the average moving speed of vehicles in a road segment are computed to detect the congested road segments. Finally, we compute the final congested routes by using a clustering scheme. The experimental results showed that the proposed scheme can efficiently discover the congested routes in different directions of the roads.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.17-22
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• 2016

In relay networks, relay nodes amplify or demodulate/remodulate the received signal from the transmitter, and transmit that signal to the receiver. The received signals from several relays are combined and used for demodulation at the receiver, which enhances the performance of the overall system. Partially differential modulation scheme which uses coherent modulation at the relay and non-coherent modulation scheme at the receiver is adopted for modulation scheme. We analyze the performance of systems depending on various energy allocations of source and relays given the total energy in relay networks.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.43-48
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• 2009

Wireless mesh networks, unlike Ad-hoc network, has low mobility and multi-path communication between terminals and other networks because it has the backbone structures. Most studies are advanced on finding the optimal routing path in multi-hop wireless mesh network environment. Various routing metric, minimum number of hops(Hop_count) and ETX, ETT metric, are proposed to wireless mesh networks. However, most metrics cannot identify the high throughput routing paths because this metric uses a different measurement parameters in each direction. So actual delivery rate does not provide to this metric. This paper describes the metric and implementation of IETC as a metric. This paper shows the improvement in performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.77-83
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• 2010

Vehicular Ad Hoc Networks are self-organizing Peer-to-Peer networks that typically have highly mobile vehicle nodes, moving at high speeds, very short-lasting and unstable communication links. VANETs are formed without fixed infrastructure, central administration, and dedicated routing equipment, and network nodes are mobile, joining and leaving the network over time. So, VANET-security is very vulnerable for the intrusion of malicious and misbehaving nodes in the network, since VANETs are mostly open networks, allowing everyone connect, without centralized control. In this paper, we propose a rough set based anomaly detection method that efficiently identify malicious behavior of vehicle node activities in these VANETs, and the performance of a proposed scheme is evaluated by a simulation in terms of anomaly detection rate and false alarm rate for the threshold ${\epsilon}$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.71-76
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• 2015

To resolve inefficient content delivery mechanism in conventional internet-based networks, Content-Centric Networks (CCN) has been proposed for wired and wireless networks. One of issues in wireless CCN-based networks is overhead to achieve reliability on content delivery because CCN uses end-to-end two-way handshake with Interest/content packets. In this paper, a novel protocol to reduce overhead and achieve reliability is proposed. The protocol allows Interest packet to request multiple data packets and multiple data packets to be sent in a row without a Interest packets. The protocol is evaluated through the simulations and the performance improvement is proved.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.104-114
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• 2005

This work presents a concept and the related analysis of the traffic performance for a wireless broadband system based on fixed relay stations acting as wireless bridges. The analysis focuses on the important performance indicators end-to-end throughput and delay, taking into account the effects of an automated repeat request protocol. An extension to a MAC frame based access protocol like IEEE 802.11e, 802.15.3, 802.16a, and HIPERLAN2 is outlined and taken as basis for the calculations. The system is intended for both dense populated areas as an overlay to cellular radio systems and to provide wide-area broad-band coverage. The two possible deployment scenarios for both dense urban and wide-area environments are introduced. Analytical and validating simulation results are shown, proving the suitability of the proposed concept for both of the mentioned scenarios. It is established that the fixed relaying concept is well suited to substantially contribute to provide high capacity cellular broad-band radio coverage in next generation (NG) cellular wireless broadband systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.6
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• pp.595-603
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• 1992

It has been establisued that the reliability of communication networks is NP hard problem owing to computationally and complexity as the number of componeuts is Increased in large networks. This paper proposed an algorithm for determining upper and lower bounds In the reliability of source-to-terminal in communication networks to solve this problem. The evaluation method follows the next procedures. First, minimal pathset and minimal cut set are serched. Second, it is sorted that the number of components is the same events and the reliability bounds Is evaluated by the section function to extract common variable. The performance of proposed algorithm is also estimate(1 as compared to the reliability of Esary-Proschan, Shogan and Copal.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.4068-4086
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• 2014

Due to the prevalence of powerful mobile terminals and the rapid advancements in wireless communication technologies, the wireless video streaming service has become increasingly more popular. Recent studies show that video streaming services via Transmission Control Protocol (TCP) are becoming more practical. TCP has more advantages than User Diagram Protocol (UDP), including firewall traversal, bandwidth fairness, and reliability. However, each video service shares an equal portion of the limited bandwidth because of the fair sharing characteristics inherent in TCP and this bandwidth fair sharing cannot always guarantee the video quality for each user. To solve this challenging problem, an Adaptive Multiple TCP (AM-TCP) scheme is proposed in this paper to guarantee the video quality for mobile devices in wireless networks. AM-TCP adaptively controls the number of TCP connections according to the video Rate Distortion (RD) characteristics of each stream and network status. The proposed scheme can minimize the total distortion of all participating video streams and maximize the service quality by guaranteeing the quality of each video streaming session. The simulation results show that the proposed scheme can significantly improve the quality of video streaming in wireless networks.