• The Journal of Engineering Geology
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• v.13 no.1
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• pp.17-27
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• 2003

In this study, a phenomenon of saltwater intrusion was monitored under various conditions regarding recharge and pumping rate using time domain reflectometry for a laboratory scale unconfined aquifer to verify the basic theory behind seawater intrusion and to investigate movement of salt-freshwater interface in accordance with the ratio of pumping and recharge rate. Results showed that a thick mixing zone was formed at the boundary instead of a sharp salt-freshwater interface that was assumed by Ghyben and Herzberg who derived an equation relating the water table depth $(H_f)$ to the depth to the interface $(H_s)$. Therefore our experimental results did not agree with the calculated values obtained from the Ghyben and Herzberg equation. Position of interface which was adopted as 0.5 g/L isochlor moved rapidly as the Pumping rate $(Q_p)$ increased for a given recharge rate $(Q_r)$. In addition, interface movement was found to be about 7 times the ratio of $Q_p/Q_r$ in our experimental condition. This indicates that Pumping rate becomes an important factor controlling the seawater intrusion in coastal aquifer.

• Journal of the Korean earth science society
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• v.25 no.6
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• pp.495-501
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• 2004

Using numerous ground-based or space-based telescopes by many astronomers, AGN spectroscopic monitoring campaigns have been carried out over many years to study the variability of continua and emission lines. We investigate the SWP IUE spectra of a large aperture configuration for the Seyfert 1 galaxies NGC 4151 and NGC 5548. We estimate the BLR electron number densities and their variation from the line ratios of C III] 1909 to Si III] 1892. With the ratios of C IV 1550 to C III] 1909 which give us the information on the ionization parameter of BLR, we try to find the physical conditions of the BLR and activities of he super massive black hole surroundings. The BLR density variations scale as 4 and 8 for NGC 4151 and NGC 5548, respectively. Based on the BLR size and C III] line profiles, we found both black hole masses as about $10^7$ $M_{\odot}$.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1041-1051
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• 2012

Attack on Cloud Computing, an intensive service solution using network infrastructure recently released, generates service breakdown or intrusive incidents incapacitating developmental platforms, web-based software, or resource services. Therefore, it is needed to conduct research on security for the operational information of three kinds of services (3S': laaS, PaaS, SaaS) supported by the Cloud Computing system and also generated data from the illegal attack on service blocking. This paper aims to build a system providing optimal services as a 4-stage defensive method through the test on the attack and defense of Cloud Computing services. It is a defense policy that conducts 4-stage, orderly and phased access control as follows: controlling the initial access to the network, controlling virtualization services, classifying services for support, and selecting multiple routes. By dispersing the attacks and also monitoring and analyzing to control the access by stage, this study performs defense policy realization and analysis and tests defenses by the types of attack. The research findings will be provided as practical foundational data to realize Cloud Computing service-based defense policy.

• KIISE Transactions on Computing Practices
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• v.23 no.7
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• pp.434-439
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• 2017

More and more people are suffering from sleep disturbance, which can have many different causes. The healthcare industry, which can help people with this disability, is one technology that is currently in the spotlight. However, current services are vulnerable to data concentration, because they are simple telemedicine services that transmit all data to a remote server and process the data on the server. They have a disadvantage in that the data cannot be streamed in real time by synchronizing the biometric data of remotely protected persons. In order to solve this problem, we propose a service structure for streaming biometric data of protected persons to a hospital or guardian in real time, using a self-organizing distributed middleware platform without a central server. We prove that it is possible to provide an effective streaming service by evaluating the service start time and average delay time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.302-308
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• 2013

Internet is becoming more common with increasing cloud services have been spreading rapidly. A SLA is agreements between service providers and customers of service providers is how to ensure quality of service. SLA in cloud computing environments from the perspective of the IT service providers to customer satisfaction increase for service quality, it will need to differentiate between competing carriers QoS guarantees with SLA is a very important factor. However, the study of SLA in the cloud is staying in its infancy. In this paper, SLA indices for cloud services defining and use them SLA Management System for QoS guarantee has been implemented. The proposed system using monitoring-based migration policy an open source-based cloud computing platform which Cluster Nodes load distribution of virtual machines assigned to their availability, response time, throughput analysis of what affects and is compared with existing cloud.

• Composites Research
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• v.18 no.1
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• pp.16-22
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• 2005

Application fields on structural health monitoring of fiber Bragg gratings (FBGs) are gradually expanded even to a primary structure as well as a secondary structure and a specimen. For the reason, verification for the reliability of FBGs such as signal characteristics and mechanical strength becomes much more important. In this study, mechanical strength characteristics of FBGs with their fabrication process and reflectivity are investigated with various grating lengths. From the results of tension tests, it is shown that the mechanical strength of optical fibers decreases about $50\%$ just by jacket stripping and the amount of decrease is dependent on stripping methods. About $55\%$ of mechanical strength of stripped optical fibers decreases if gratings are formed in the core and it is regardless of grating lengths and reflectivity. However, the width of strength distribution increases relative to increases in reflectivity.

• Journal of Internet Computing and Services
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• v.6 no.4
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• pp.75-84
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• 2005

Grid computing enables a shift from a localized resource computing model to a fully-distributed virtual organization with shared resources, Accounting is one of the main obstacles to widespread adoption of the Grid. Accounting has until recently, been a sparsely-addressed problem, particularly in practice. In this paper, we design and implement the accounting information gathering system. Accounting information gathered at each local system does not include grid-aware information. To be useful in grid environment, grid user information must be included in accounting information. To make it useful in grid environment, we add grid user information with PGAM. Implemented system is based on OGSA, following GSAX framework of RUS-WG in GGF. And the schema of accounting information is following usage Record Fields of UR-WG in GGF. Also, the accounting information integrating and monitoring tool for system management in the Grid environment are implemented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.12
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• pp.976-983
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• 2013

The targets for the traditional IT management solutions has been mostly systems (server) and networks. Such that management system for system and network, SMS and NMS respectively, used be the IT management solutions. Now the speed of hardware improvement is faster than ever, the performance improvement scope is shifting from hardware towards software. Therefore, it is not arguable that the business success depends on the efficient and optimized application performance management. There are many different approaches are developed in the application performance management, but in this study, API-based logging system that most efficiently visualizes the correlation of call and response between Components and enables active performance management for monitoring real-time applications operation status and resolving the problems and failures quickly.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.227-232
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• 2006

스마트 의류의 발달은 pc 를 분산, 부착한 웨어러블 컴퓨터의 연구로부터 진행되어 왔으며, 1990 년대 후반 이후 착용자 감성을 고려해 더욱 편안하며, 의복과 유사한 외관을 디자인 하려는 노력이 전개되고 있다. 스마트 의류는 엔터테인먼트, 비즈니스, 스포츠, 의료 분야에 적용 등 다양한 애플리케이션으로 연구, 개발되고 있으며, 최근 들어서는 생체신호 센서를 이용한 건강관리용 스마트 의류의 연구가 주목 받고 있다. 건강에 대한 관심과 라이프 스타일의 변화, 고령화 사회의 예상으로 인해 건강복지에 대한 필요성이 증가하는 최근 트렌드를 볼 때, 건강 관리용의 스마트 의류의 수요는 증가될 것으로 예상된다. 이에 본 연구에서는 기본적인 생체신호 뿐 아니라 심장 질환, 호흡기 질환을 측정할 수 있는 건강 개념의 스마트 의류 디자인을 개발하였다. 이 스마트 의류는 기존의 의복의 형태와 착용감은 그대로 유지하면서 의복 착장 시 생체 신호를 전송, 모니터링 할 수 있도록 설계하였다. 개발된 의복은 심전도, 체온 센서로 구성되어 있으며, 이를 통해 심전도, 호흡량, 맥박, 체온 등의 생체신호를 얻을 수 있다. 디자인 프로토타입의 기기 위치 선정은 선행 연구에서 제시한 '착용성 향상을 위한 웨어러블 컴퓨터 디자인 지침' 을 기반으로 설계하여 착장 시 기기로 인한 이물감이 느껴지지 않도록 하였으며 또한, 기기의 하중을 최소화 하였다. 의복의 디자인은 센서의 안정된 부착과 활동성, 센서의 정확한 측정을 고려하여 표피의 면적 변화를 고찰하여 디자인하였다. 이 스마트 의류는 노인, 건강 이상자, 통원 치료자에게 평상시의 건강을 체크 함으로써 보다 원활한 치료의 가능으로 의료 복지에 기여할 것으로 예상되며, 디자인 프로토타입의 개발을 통하여 센서기반 스마트 의류의 가능성을 제시했다는 점에서 이 연구의 의의가 있다.

• Journal of Radiation Protection and Research
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• v.25 no.4
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• pp.197-205
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• 2000

A prototype electronic dosimeter(PED) adopting a silicon PIN diode detector as a radiation detector has been developed, manufactured and test-evaluated. A radiation signal processing circuit has been electronically tested and then the radiation detection characteristics of this PED has been performance-tested by using a reference photon radiation field. As a result in a electronic performance test, radiation signals from a detector were well observed in the signal processing circuit. The radiation detection sensitivity of this PED after several test-irradiations to $^{137}Cs$ gamma radiation source appeared to be 1.85 cps/$Gy{\cdot}h^{-1}$ with 19.3% of the coefficient of variation, which satisfied the performance criteria for the active personnel radiation monitor. Further improvement of the electronic circuit and operating program will enable the PED to be used in personal monitoring purpose.