• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.11
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• pp.1256-1263
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• 2012

Assigning different frequency resources among adjacent cells, namely the frequency reuse technique can be utilized to mitigate intercell interference, which is a major cause of performance degradation in cellular systems. Since most of conventional frequency reuse patterns are limited to the two-dimensional environment, the research for the three-dimensional frequency reuse would be beneficial especially for the implementation of femto cells in downtown office buildings. We propose frequency reuse patterns in three-dimensional space and evaluate their performance of each pattern in terms of channel capacity. In particular, we show that the proposed three-dimensional frequency reuse patterns can be applied for carrier-aggregated transmission of LTE-Advanced systems. The performance of the proposed patterns is evaluated using computer simulation.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.69-72
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• 2008

The so-called Pier-Shafts system which consists of the continuous column and shaft is often used to support the highway bridge structure because of advantages in easy construction and low cost. In the earthquake region, the Pier-Shafts system undergoes large displacements and represents a nonlinear behavior under the lateral seismic loading. The soil-pile interaction should be considered for more accurate analysis of the Pier-Shafts system. In this study, a transverse response of a reinforced concrete Pier-Shafts system inside multi-layered soil medium is predicted using a finite element program which adopts an elasto-plastic interface model for the interface behavior between the shaft and the soil. Then, seismic analysis is performed to evaluate the performance of Pier-Shafts system under strong ground motion and their results are verified with experimental data.

• Korean Journal of Social Welfare
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• v.65 no.1
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• pp.83-107
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• 2013

The purpose of this study is to understand the life experiences of an adult adoptee. For this purpose, the data were collected through in-depth interviews with an adult adoptee, observation, and documents and analyzed using life history approach. Results of analysis were composed of summarized life history, thick description of life history, theme analysis, and issues for intervention. The themes generated from analysis are 'a slub', 'a larva that want to be a butterfly', 'I am okay. No, I am not okay', 'because it is not my fault', 'love, the critical determinant leading my life'. Researchers, also, examined intervention issues of adoption, post-adoption service, closed adoption or open adoption, searching root, intervention for adult adoptee. Based on the results of this study, the policies and practical guidelines for adult adoptees were suggested.

• Korean Journal of Social Welfare
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• v.65 no.1
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• pp.5-31
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• 2013

The principle objective of this study is to determine factors affecting social participation for physically disabled people with musculoskeletal conditions (spinal cord injury, muscular dystrophy, osteogenesis imperfecta, rheumatoid arthritis) in South Korea using ICF relevant categories of the international classification index by WHO. The subjects of this study 352 people with physical disabilities, the data were collected using ICF component(body functions, body structures, activities and participation and environmental factors) and the relevant categories deprived from ICF core sets. The collected data were evaluated with descriptive analysis, ANOVA, correlation analysis, and multiple regression analysis. The results of this study can be summarized as follow. The mental function, Neuromusculoskeletal and movement-related functions, Genitourinary and reproductive functions, Skin and related structures, Learning and applying knowledge, General tasks and demands, and Mobility positively influenced social participation in people with musculoskeletal conditions. However individual factors and environmental factors didn't statistically significant affect on social participation. The implications of the study is to examine by ICF components of universal approach on disability study and utilized the relevant ICF categories as measurement tools.

• Journal of the Korean Geotechnical Society
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• v.21 no.7
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• pp.21-29
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• 2005

This paper presents the results of a numerical investigation on the behavior of a geosynthetic reinforced two-tier segmental retaining wall (GR-SRW) on a yielding foundation. A hypothetical 10 m high two tier GR-SRW to be constructed on an incompetent foundation containing a layer of relative soft soil deposit was considered. A verified finite-element procedure was employed to get insights into the effect of foundation yielding on the wall behavior including the wall deformation and the reinforcement load. It is shown that the effect of foundation yielding is to increase the wall deformation as well as the reinforcement load, thus influencing both the internal as well as the external stability of the wall. Practical implications of the findings obtained from this study are highlighted in this paper.

• Convergence Security Journal
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• v.5 no.4
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• pp.67-72
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• 2005

The exponential increase of malicious and criminal activities in cyber space is posing serious threat which could destabilize the foundation of modern information society. In particular, unexpected network paralysis or break-down created by the spread of malicious traffic could cause confusion and disorder in a nationwide scale, and unless effective countermeasures against such unexpected attacks are formulated in time, this could develop into a catastrophic condition. In order to solve a same problem, this paper researched early detection techniques for only early warning of cyber threats with separate way the detection due to and existing security equipment from the large network. It researched the cyber example alert system which applies the module of based honeynet from the actual large network and this technique against the malignant traffic how many probably it will be able to dispose effectively from large network.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.4
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• pp.23-30
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• 2000

Cogeneration systems are seen as a significant innovation for dispersed energy generation since they are both environmentally friendly and has comparatively high degrees of efficiency. It is especially suited for the decentralized provision of electricity and heat. However, it causes operational problems such as voltage regulation, voltage variation, protection and safety. Especially, it is expected that the interconnection/disconnection operation of cogeneration system has an effect on distribution voltage regulation and variation. Recently, with the increased use of customer-owned computers and other sensitive electronic equipment, electric power quality has become an important concerns. Therefore, the voltage quality problems with cogeneration system should be investigated because the voltage quality is an important part of electrical power quality. In this paper, the momentary voltage dips associated with the interconnection/disconnection operation of cogeneration system are analyzed, including restraint solutions at the customer level. In addition, the unit capacity of cogeneration systems per feeder are evaluated from the view point of momentary voltage variations. The results of this paper are useful analysis data for interconnection standards/guidelines of cogeneration systems and dispersed generation (DG)

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1634-1642
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• 2014

Mobile RFID system, that consists of the existing RFID reader mounted on the mobile devices such as smartphones, is able to provide the users a variety of services and convenience. But security of mobile RFID system is too weak like the existing RFID system. In this paper, the mobile RFID mutual authentication protocol with high level of security is proposed to overcome the troubles such as cryptographic protocols in the existing RFID system responding with the same value in every authentication procedure and the exposure in the exchange of messages. The proposed protocol exchanges messages unexposed by using the random numbers generated in the mutual authentication between the tag and the reader and making numbers coded with the symmetric key. Besides, the protocol uses the mutual authentication utilizing OTP by considering the characteristics of the reader embedded in mobile devices in the mutual authentication process between the reader and the server. Because changed message in every authentication, which produces safe from spoofing attacks and replay attacks, etc.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.271-274
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• 2013

Considering the recent trend highlighting the importance of STEAM education, the purpose of this study is to develop scientific research activities and STEAM technology material using the smart device sensor. Drawing a picture on a map with GPS drawing application which contains elements such as IT, geographic information, sports and arts, we intent not just to install a smartphone application but also to get synergic effects and help with real cartography and geographic classes which are not experienced in the middle school curriculum, by using the functions of a smart device. Through the development of STEAM teaching material, we intended to provide a clear direction towards advancement by developing creative teaching data and teaching models which encourage students to improve their interest and creativity in science, technology, engineering, art, and mathematics.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.491-494
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• 2017

Recently, IoT has been supported by ICT technology with a variety of ICT powers. In May 2014, Information and Communication Strategy Committee announced the 'Basic plan for Internet of Things'. Also on Febuary 24 this SAME year, KISA(Korea Internet&Security Agency) provides many projects related to IoT, such as announcement of 'K-Global Project' for start-up and venture support related to IoT and ICT companies. In contrast to the various services of Internet of Things, when a connection is made between object-to-object or person-to-object wired and wireless networks, security threats have occurred in the process of communication. We analyzed these kinds of security threats related to Internet of things, and gave a consideration for requirement.