• Korean Chemical Engineering Research
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• v.47 no.5
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• pp.558-564
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• 2009

POF(Polymer optical fiber) offers advantages of lighter, inexpensive, and easier to use over GOF(glass optical fiber). Its higher transmission loss and low bandwidth, however, make it suitable only for short distance networking such as LAN. The polymer materials and its synthesis technology of low transmission loss and the broader application for flexible POF are the two of many critical areas to be investigated more. In the current study, low-noise POF modules are developed and optimized with a low noise amplifier and low cost LED of 650 nm. In order to demonstrate the dynamic characteristics of the POF module for optical communication and sensing, we have built an image transfer module, optical transmission speed measurement module, optical transceiver for RS-232, and sound-transfer module, and the signal characteristics of them are evaluated. It is found that the module can be readily used for a quick and simple measurement of optical transfer speed. With help of analog amplifier, LED, and PD, sound and image transfers through a maximum 60 m optical waveguide have been confirmed. Real-time data transfer was also demonstrated in PID control, which is thought to be valuable to industrial plant design and control.

• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.469-476
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• 1998

In the case of acquisition and displaying medical Images such as ultrasonography and endoscopy on VGA monitor of PC system, image degradation of tear-drop appears through scan conversion. In this study, we compare several methods which can solve this degradation and implement the hardware system that resolves this problem in real-time with PC. It is possible to represent high quality image display and real-time processing and acquisition with specific de-interlacing device and PCI bridge on our hardware system. Image quality is improved remarkably on our hardware system. It is implemented as PC-based system, so acquiring, saving images and describing text comment on those images and PACS networking can be easily implemented.metabolism. All images were spatially normalized to MNI standard PET template and smoothed with 16mm FWHM Gaussian kernel using SPM96. Mean count in cerebral region was normalized. The VOls for 34 cerebral regions were previously defined on the standard template and 17 different counts of mirrored regions to hemispheric midline were extracted from spatially normalized images. A three-layer feed-forward error back-propagation neural network classifier with 7 input nodes and 3 output nodes was used. The network was trained to interpret metabolic patterns and produce identical diagnoses with those of expert viewers. The performance of the neural network was optimized by testing with 5~40 nodes in hidden layer. Randomly selected 40 images from each group were used to train the network and the remainders were used to test the learned network. The optimized neural network gave a maximum agreement rate of 80.3% with expert viewers. It used 20 hidden nodes and was trained for 1508 epochs. Also, neural network gave agreement rates of 75~80% with 10 or 30 nodes in hidden layer. We conclude that artificial neural network performed as well as human experts and could be potentially useful as clinical decision support tool for the localization of epileptogenic zones.

• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.317-326
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• 2010

Nowadays, transmission bandwidth for network traffic is increasing and the type is varied such as peer-to-peer (PZP), real-time video, and so on, because distributed computing environment is spread and various network-based applications are developed. However, as PZP traffic occupies much volume among Internet backbone traffics, transmission bandwidth and quality of service(QoS) of other network applications such as web, ftp, and real-time video cannot be guaranteed. In previous research, the port-based technique which checks well-known port number and the Deep Packet Inspection(DPI) technique which checks the payload of packets were suggested for solving the problem of the P2P traffics, however there were difficulties to apply those methods to detection of P2P traffics because P2P applications are not used well-known port number and payload of packets may be encrypted. A proposed algorithm for identifying P2P heavy traffics based on flow transport parameters and behavioral characteristics can solve the problem of the port-based technique and the DPI technique. The focus of this paper is to identify P2P heavy traffic flows rather than all P2P traffics. P2P traffics are consist of two steps i)searching the opposite peer which have some contents ii) downloading the contents from one or more peers. We define P2P flow patterns on these P2P applications' features and then implement the system to classify P2P heavy traffics.

• Clinical and Experimental Pediatrics
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• v.52 no.11
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• pp.1185-1193
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• 2009

An act of children's welfare was made in 1961 for the first time in Korea but it had been nothing but the name in view of practical impact to prevention of child abuse. Real undertakings of Child Abuse Prevention were commenced overtly since 2000 in Korea, when the law for children's welfare was revised to put protective settings for the victims and to establish criterion for children's safety. The history of Child Abuse Prevention is very short in Korea but the reporting cases increased very fast from 4,133 cases in 2001 up to 9,570 cases in 2008 with the enthusiastic activities from people of the associated organizations along with the national supports. But the portion reported by the mandated reporters such as teachers or doctors is still low compared to those of the developed countries. The National Child Protection Agency (NCPA) was founded in 2001 by the Ministry of Health and Welfare to prevent child abuse and to aid recovery of abused and neglected children including their families, through the cooperation of related organizations. NCPA refers reported cases of child abuse to appropriate local centers, operates a computer database system for case management, publicizes national reports of child abuse on a yearly basis and technically supports the Local Child Protection Agency (LCPA) by developing scales for assessment of child abuse and neglect and distributing programs for the education of mandatory reporters. LCPAs operate 24-hour telephone hotline, investigate and visit homes and provide in home services networking with local resources, and operate multidisciplinary teams for screening child abuse victims and supervising case management through multimodal systems. We summarized the present state of child abuse in Korea and reviewed the operating systems for child protection in this country. Through this article, we hope that medical peoples are to be informed on the seriousness of child abuse and to be able to devote themselves for the prevention of child abuse.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.65-71
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• 2009

As a core area of the new computing paradigm, the Ubiquitous Sensor Network Technology utilizes a wireless sensor networking which can be applied to the Context Information Monitoring System. When the technology is used in a poor user-environment for monitoring purposes, it can cost-effectively gather the context data on real-time basis, analyze the information gathered, effectively response to the user situation, and execute orders to create environmental factors desired by the user. This study structures a system able to monitor information in regards to a user-environment based on wireless-node sensor technology coupled with the Ubiquitous Sensor Network Technology. In this paper, the protocol in which it manages the wireless sensor network as the zone based by using the management protocol standardized at the smart home with a profile is proposed. The proposed system requires a minimal collection of data without continuous monitoring. Monitoring periodically, it can sense the user-environment more efficiently than the existing monitoring technologies based on the wire-communication technology.

• Journal of Intelligence and Information Systems
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• v.23 no.2
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• pp.89-105
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• 2017

As the advances of technology in mobile networking and the popularity of online social networks (OSNs), the mobile social networks (MSNs) provide opportunities for marketing strategy. Therefore, understanding the information diffusion in the emerging MSNs is a critical issue. The information diffusion address a problem of how to find the proper initial nodes who can effectively propagate as widely as possible in the minimum amount of time. We propose a new diffusion scheme, called Hotspot DBC, which is to find k influential nodes considering each node's mobility behavior in the hotspot zones. Our experiments were conducted in the Opportunistic Network Environment (ONE) using real GPS trace, to show that the proposed scheme results. In addition, we demonstrate that our proposed scheme outperforms other existing algorithms.

• The KIPS Transactions:PartA
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• v.14A no.5
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• pp.295-300
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• 2007

The Linux-based embedded systems such as mobile telephones. PDAs and MP3 players are widely in use. USB(Universal Serial Bus) is the interface for data communication between the computers and these peripheral devices. Some embedded systems like intelligent home networking and multimedia streaming require guaranteed QoS(Quality of Service), which is needed for real time transmission of UDP/IP messages through USB. Although USB Ethernet driver is supported by USB Gadget API in Linux, it is unable to provide the desirable QoS required by each type or small embedded systems due to the unpredictability or TCP/IP Stack in Linux. This paper proposes IP-Over-USB to improve QoS of UDP/IP message transmission in the embedded systems using USB in Linux system.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.566-572
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• 2004

In this paper, we define the secure authentication model to provide a mobile node with global roaming service and integrate the Fast Handoff scheme with our approach to minimize the service latency. By starting the AAA(Authentication, Authorization and Account) procedure with Fast Handoff simultaneously when a roaming occurs, authentication latency is reduced significantly and provision of fast and seamless service is possible. The previous works such as IPsec(Internet Protocol Security), RR (Return Routability) and AAA define the procedures performed after the completion of Layer2 Handoff which leads us to study a way of providing the real time and QoS guaranteed service during this period. The proposed scheme is for this goal and when appling it to roaming environment it shows the cost reduction up to 55% and 17% for the case of the MN receiving the FBACK and not respectively before L2 Handoff occurs.

• Journal of KIISE:Information Networking
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• v.34 no.1
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• pp.48-61
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• 2007

WiBro (Wireless Broadband) service, developed in Korea, can provide the host mobility while its users hang around within the subnet. Next-generation Internet protocols, IPv6 and Mobile IPv6 (MIPv6), provide a plenty of addresses to the nodes and enable the handover between different subnets. However, MIPv6 is not enough to support a real time service such as VoIP (Voice over IP) due to the long latency, and it is necessary to develop an enhanced handover mechanism which is optimized to the WiBro networks. In this paper, we suggest an improved fast handover mechanism while the mobile node moves around WiBro networks. The proposal is based on Fast Mobile IPv6 (FMIPv6) which is the representative protocol for fast handover, and reduces the handover latency by the close interaction between the link layer (WiBro MAC) and IP layer (FMIPv6). Finally, we analyze the performance of proposed mechanism through the mathematical analysis.

• Journal of KIISE:Information Networking
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• v.36 no.2
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• pp.69-79
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• 2009

Today's Internet is one of the necessaries of our life. Anomalies of the Internet provoke social problems. For that reason, Internet Measurement which studies characteristics on Internet traffic attracts pubic attention. Recently, Traffic Dispersion Graph (TDG), a novel traffic analysis method, was proposed. The TDG is not a statistical analysis method but a graphical visualization method on interactions among network components. In this paper, we propose a new anomaly detection paradigm and its technique using TDG. The existing studies have focused on detecting anomalous packets of flows. On the other hand, we focus on detecting the sources of anomalous traffic. To realize our paradigm, we designed the TDG Clustering method. Through this method, we could classify anomalous hosts infected by various worm viruses. We obtained normal traffic through dropping traffic of the anomalous hosts. Especially, we expect that the TDG clustering method can be applied to real-time anomaly detection because calculations of the method are fast.