• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.27-32
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• 2019

Along with the growth of u-Healthcare, we propose a security enhancement based on network separation for CloudHIS with for handling healthcare information to cope with cyber attack. To protect against all security threats and to establish clear data security policies, we apply desktop computing servers to cloud computing services for CloudHIS. Use two PCs with a hypervisor architecture to apply physical network isolation and select the network using KVM switched controller. The other is a logical network separation using one PC with two OSs, but the network is divided through virtualization. Physical network separation is the physical connection of a PC to each network to block the access path from both the Internet and the business network. The proposed system is an independent desktop used to access an intranet or the Internet through server virtualization technology on a user's physical desktop computer. We can implement an adaptive solution to prevent hacking by configuring the CloudHIS, a cloud system that handles medical hospital information, through network separation for handling security enhancement.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2004.11a
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• pp.31-35
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• 2004

정보통신 기술의 발달과 디지털 방송의 시작, 뉴미디어의 출현으로 인한 통신과 방송의 융합은 가속화되고 있다. 또한 2010년까지 광대역통신망 BcN과 홈네트워크 구축을 위한 정부정책이 실행 중에 있다. 100Mbps의 전송속도를 구현해야 하는 광대역 통신망(BcN)을 위해 기존 인터넷 백본 1)망은 잘 구축이 되어 있으나 가입자까지의 망 구조에 많은 문제점을 앉고 있다. 기존 전화국을 이용한 XDSL과 지역 SO를 활용한 Cable Modem의 경우 병목현상과 이론상 속도 또한 BcN과 통방통합이 요구하는 50-100Mhz의 전송속도를 만족하지 못한다. 새로운 망 구조를 구축하기 위해 많은 비용과 시간의 소요가 예상된다 가입자 망 구축에 따른 많은 방법과 이론이 제시되고 있다. 똔 논문에선 지역 SO를 활용하여 가입자까지 망을 통방통합과 BcN에 적합한 가입자 망을 새롭게 구성하는 것을 목표로 한다. 먼저 지역 50의 망을 활용하기 위해선 기존 KT와 파워콤의 COF(Glass Optical Fiber)망과 지역 케이블 SO의 HFC 망을 이용하기에는 동축케이블 망의 물리적 특성에 따른 한계로 통방통합과 BcN에 부적합하다. Tree And Branch 구조의 HFC망 대신 $SMF^{2)}$의 기존 SO의 자가망을 새롭게 설계하고 광분배망 기술인 $E-PON^{3)}$방식을 접목시켜 최대한 동축망을 사용하지 않고 굴곡 특성에 약한 $FOG^{4)}$의 특성을 극복하기 위해 $POF^{5)}$망을 이용하여 댁내 홈게이트웨이까지 연결하는 방식으로 지역 SO를 거점으로 활용하여 댁내까지 FHHT와 홈 네트워크까지의 가입자 망을 새롭게 구성하고자 한다. 저장의 효율성을 위해 이진 포멧인 IPMP화된 MP4 파일을 생성할 수 있다.으로써, 에러 이미지가 가지고 있는 엔트로피에 좀 근접하게 코딩을 할 수 있게 되었다. 이 방법은 실제로 Arithmetic Coder를 이용하는 다른 압축 방법에 그리고 적용할 수 있다. 실험 결과 압축효율은 JPEG-LS보다 약 $5\%$의 압축 성능 개선이 있었으며, CALIC과는 대등한 압축률을 보이며, 부호화/복호화 속도는 CALIC보다 우수한 것으로 나타났다.우 $23.87\%$($18.00\~30.91\%$), 갑폭 $23.99\%$($17.82\~30.48\%$), 체중 $91.51\%$($58.86\~129.14\%$)이였으며 성장율은 사육 온도구간별 차는 없었다.20 km 까지의 지점들(지점 2에서 지점 6)에서 매우 높은 값을 보이며 이는 조석작용으로 해수와 담수가 강제혼합되면서 표층퇴적물이 재부유하기 때문이라고 판단된다. 영양염류는 월별로 다소의 차이는 있으나, 대체적으로 지점 1과 2에서 가장 낮고, 상류로 갈수록 점차 증가하며 지점 7 상류역이 하류역에 비해 높은 농도이다. 월별로는 7월에 규산염, 용존무기태질소 및 암모니아의 농도가 가장 높은 반면에 용존산소포화도는 가장 낮다. 그러나 지점 14 상류역에서는 5월에 측정한 용존무기태질소, 암모니아, 인산염 및 COD 값이 7월보다 다소 높거나 비슷하다. 한편 영양염류와 COD값은 대체적으로 8월에 가장 낮으나 용존산소포화도는 가장 높다.출조건은 $100^{\circ}C$에서 1분간의 고온단시간 추출이 적합하였다. 증가를 나타내었는데

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.9
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• pp.1666-1673
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• 2017

Republic of Korea is divided into South Korea and North Korea, creating military conflicts and social conflicts. North Korea is conducting cyberattacks against South Korea and has hacked South Korea's defense network. In the world of cyberspace, the boundaries of the borders are becoming obscured, and cyberattacks and cyberterrorism for cyberwarfare operate with digital computing connected to points, time and space. Agenda and manual are needed for national cybersecurity. Also, it is necessary to study national cybersecurity laws and policies that can create and implement nationalcyber security policy. This paper investigates cyberterrorism situation in North and South Korean confrontation situation and damage to cyberwarfare in the world. We also study cybersecurity activities and cyberwarfare response agendas, manuals and new technologies at home and abroad. And propose national cybersecurity policy and propose policies so that '(tentative) The National Cybersecurity Law' is established. This study will be used as basic data of national cybersecurity law and policy.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.1
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• pp.20-33
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• 2002

Usage of ATM AAL2 packets becomes dominant to increase transmission efficiency of voice traffic in the backbone network. In case of voice service that uses AAL2 mechanism, if resources of network are enough, connection of new call is accepted. However, due to packets generated by the new call, transmission delay of packets from old calls can increase sharply. To control this behavior, in this paper we present an AAL2 buffer management scheme that allocates a virtual buffer to each call and after calculating its propagation delay variation(PDV), decides to drop packets coming from each call according to the PDV value. We show that this packet dropping algorithm can effectively prevent abrupt QoS degradation of old calls. To do this, we analyze AAL2 packet composition process to find a critical factor in the process that influences the end-to-end delay behavior and model the process by K-policy M/D/1 queueing system and MIN(K, Tc)-policy M/D/1 queueing system. From the mathematical model, we derive the probability generating function of AAL2 packets in the buffer and mean waiting time of packets in the AAL2 buffer. Analytical results show that the AAL2 packet dropping algorithm can provide stable AAL2 packetization delay and ATM cell generation time even if the number of voice sources increases dramatically. Finally we compare the analytical result to simulation data obtained by using the COMNET Ⅲ package.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.246-246
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• 2021

본 연구는 강우 발생시 유량을 추정하는 것에 목적이 있다. 이를 위해 본 연구는 선행연구의 모형 개발방법론에서 벗어나 딥러닝 알고리즘 중 하나인 합성곱 신경망 (convolution neural network)과 수문학적 이미지 (hydrological image)를 이용하여 강우 발생시 유량을 추정하였다. 합성곱 신경망은 일반적으로 분류 문제 (classification)을 해결하기 위한 목적으로 개발되었기 때문에 불특정 연속변수인 유량을 모의하기에는 적합하지 않다. 이를 위해 본 연구에서는 합성곱 신경망의 완전 연결층 (Fully connected layer)를 개선하여 연속변수를 모의할 수 있도록 개선하였다. 대부분 합성곱 신경망은 RGB (red, green, blue) 사진 (photograph)을 이용하여 해당 사진이 나타내는 것을 예측하는 목적으로 사용하지만, 본 연구의 경우 일반 RGB 사진을 이용하여 유출량을 예측하는 것은 경험적 모형의 전제(독립변수와 종속변수의 관계)를 무너뜨리는 결과를 초래할 수 있다. 이를 위해 본 연구에서는 임의의 유역에 대해 2차원 공간에서 무차원의 수문학적 속성을 갖는 grid의 집합으로 정의되는 수문학적 이미지는 입력자료로 활용했다. 합성곱 신경망의 구조는 Convolution Layer와 Pulling Layer가 5회 반복하는 구조로 설정하고, 이후 Flatten Layer, 2개의 Dense Layer, 1개의 Batch Normalization Layer를 배열하고, 다시 1개의 Dense Layer가 이어지는 구조로 설계하였다. 마지막 Dense Layer의 활성화 함수는 분류모형에 이용되는 softmax 또는 sigmoid 함수를 대신하여 회귀모형에서 자주 사용되는 Linear 함수로 설정하였다. 이와 함께 각 층의 활성화 함수는 정규화 선형함수 (ReLu)를 이용하였으며, 모형의 학습 평가 및 검정을 판단하기 위해 MSE 및 MAE를 사용했다. 또한, 모형평가는 NSE와 RMSE를 이용하였다. 그 결과, 모형의 학습 평가에 대한 MSE는 11.629.8 m3/s에서 118.6 m3/s로, MAE는 25.4 m3/s에서 4.7 m3/s로 감소하였으며, 모형의 검정에 대한 MSE는 1,997.9 m3/s에서 527.9 m3/s로, MAE는 21.5 m3/s에서 9.4 m3/s로 감소한 것으로 나타났다. 또한, 모형평가를 위한 NSE는 0.7, RMSE는 27.0 m3/s로 나타나, 본 연구의 모형은 양호(moderate)한 것으로 판단하였다. 이에, 본 연구를 통해 제시된 방법론에 기반을 두어 CNN 모형 구조의 확장과 수문학적 이미지의 개선 또는 새로운 이미지 개발 등을 추진할 경우 모형의 예측 성능이 향상될 수 있는 여지가 있으며, 원격탐사 분야나, 위성 영상을 이용한 전 지구적 또는 광역 단위의 실시간 유량 모의 분야 등으로의 응용이 가능할 것으로 기대된다.

• Korean Journal of Community Nutrition
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• v.25 no.5
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• pp.416-429
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• 2020

Objectives: This study examined the personal, interpersonal and community factors related to food sufficiency and variety among Korean adults using data from the 2017 Community Health Survey. Methods: A total of 228,310 adults aged ≥ 19 years were classified into three groups: food sufficiency with variety, food sufficiency without variety and food insufficiency. Personal factors included sociodemographic characteristics, health behavior and health status. Interpersonal factors included social networking and social activities, and community factors included safety, natural environment, living environment, availability of public transportation and health care services. The association of food sufficiency and variety with interpersonal and community factors was assessed using multivariable logistic regression analyses. Results: Of the total sample, the food-sufficiency-without-variety group and food insufficiency group accounted for 31.5% and 3.2%, respectively. The sociodemographic factors associated with food insufficiency and non-variety were women, ≥ 65 years of age, with low education level, low household income, unemployed, single, and living in areas of small population sizes. There were significant differences in health behavior and health status, interpersonal and community factors among the three groups. Multivariable logistic regression analyses conducted after adjusting for confounding factors showed that lack of social networking and social activities and lower satisfaction derived from community environments were associated with the risk of food insufficiency and non-variety. Conclusions: Our results showed that interpersonal and community factors as well as personal factors were related to food sufficiency and variety. Therefore, public policies to help build social networks and participation in social activities, and improve community environment are needed together with food assistance to overcome the problems of food insufficiency and non-variety.

• Journal of Korea Water Resources Association
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• v.53 no.9
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• pp.671-680
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• 2020

This study aims to explore structural properties and central actors of the local water policy system through a network approach, and to suggest practical implications for establishing collaborative water governance at the local level. Especially, this study conducts a social network analysis to empirically analyze the actors' roles and relationships of water management in Jeju Special Self-Governing Province and represent them with sociograms. In this study, the local water management network is divided into two dimensions: official work network, public-private policy network based on information-sharing and consultation. Also, the networks are divided into a whole network and two sectoral networks(water-use/water-quality). This study found some meaningful differences of structural properties and central actors not only in the official work networks and the policy networks but also in the water-use networks and the water-quality networks. Thus, public managers should diagnose and manage the relational properties among multiple stakeholders in local water sector through a network perspective. In particular, (1)co-operation between the administrative departments responsible for water-use and water-quality, and (2)information-sharing and consultation among public and private stakeholders should be improved to establish collaborative local water governance.

• The KIPS Transactions:PartD
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• v.16D no.1
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• pp.133-138
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• 2009

This paper introduces a pilot CDMA network-based wireless lap time measurement system set up on a ski slope of Yongpyong Ski Resort. The wireless lap time measurement system is one output of U-Sports Project of Gangwon Province, which is intendended for promoting local strategic business and preparation for hosting 2018 Winter Olympic Games at Pyeongchang. A pair of laser sensors is installed at the entry and exit points of a section requiring lap time measurement on a ski slope. Each laser sensor is connected to a sensor node via wire so that the sensor node can detect the time when a skier enters or exits the section. Also each sensor node is connected to a CDMA network via a modem and receives a standard time from a NTP server. Each node executes the NTP algorithm to synchronize its local time to the received server time. As a result of the time synchronization, the sensor nodes maintain its local time within a resolution of at least 10 miliseconds and transmit the time of detection to a central control center. While the wireless lap time measurement system introduced in the paper does not need expensive measurement equipment, the system allows the central control center to provide lap time records in a more convenient manner compared to conventional manual lap time measuremnt methods.

• (The)Korea Educational Review
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• v.18 no.1
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• pp.253-281
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• 2012

This qualitative study explores how Mongolian migrant workers, with a marked tendency for family migration, plan and put into practice their child's education and attach meaning to it in relation to the social network they form during their stay in Korea. Specifically, it analyzes in particular ways the social network Mongolian migrant workers form affect their settlement in Korea, the process by which the social network affects their planning of their child's education, and how the education planning and its realization lead to the formation of new social networks. The results show that parents were divided between those who made a deliberate decision in sending their child to the Seoul Mongol School as a part of their plan and those who chose the school due to forced circumstances. While some parents preferred the Seoul Mongol School over regular Korean schools for their child's education and future, others sent their child to the Seoul Mongol School, regardless of their preference, because they did not have access to information about regular Korean schools, were afraid of divulging their illegal status, or were afraid their child would not be able to adjust to the school life in Korean schools. Based on such analysis, this paper stresses the urgency of further research in this area, and suggests direction for future policy measures.

• Journal of Digital Convergence
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• v.11 no.10
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• pp.255-262
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• 2013

Data envelopment analysis(DEA) is a linear programming procedure designed to evaluate the relative efficiency of a set of peer entities called decision making units which use the same inputs to produce the same outputs. It has been widely employed in a variety of disciplines as an efficiency or performance measurement tool for comparing a set of entities such as firms, banks, hospitals, nations and organizations. The method, however, cant's make the priority of their performance when many units have efficiency score of unity or 100 percent. In this paper, we propose a new approach which combine qualitative method(graphical approach using network analysis) and quantitative method(super-efficient analysis using DEA), and present the results of an empirical analysis using the data of the Korean professional baseball players. As a result, there were 12 DMU that priority is hardly realized through DEA. However, this problem could be solved with super-efficiency analyzing. Also, more in-depth interpretation was able through integrating results of dendrogram and super-efficiency analyzing and prospecting it in qualitative, quantitative ways.