• The KIPS Transactions:PartA
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• v.11A no.4
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• pp.297-302
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• 2004

In the information-oriented society, the paradigm of education has changed from the existing traditional teaching-centered education to the learning-centered education. In the Web-based Learning System which an learning-centered educational environment using the internet, students should have responsibility of their learning as taking more opportunities to participate their learning positively, to control their process of learning and to evaluate their learning by themselves to improve self-directed loaming ability. In this paper, the Web-based Learning System with a Self-Study Plan to lead students to select own purposes and methods of the study and write a self_evaluation is developed. The Self-Study Plan is a guide to lead the process, an order to have an individualized study and a report to evaluate own study. In addition, the suggested System is designed through object-oriented method using the extension mechanism of UML to archive the improvement of reuse and maintenance.

• The Journal of the Korea Contents Association
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• v.9 no.2
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• pp.453-461
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• 2009

In this paper, we design and implement a web-based courseware where learners can do self-directed learning to study Web programming languages such as Html, CSS, JavaScript and Dhtml. Each section consists of text class, movie class, practice class, formative assessment, laboratory and bulletin board. And our courseware makes teachers to teach, assess and give scores to learners on Web. In our Web courseware, learners can play a movie class and practice Web programming codes in one screen simultaneously, and execute codes and confirm a results in the same screen also. Therefore, learners can understand Web programming languages efficiently, which are hard to understand immediately by text.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.338-344
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• 2017

In this paper, two-way amplify-and-forward relay methods are investigated where two terminals and one relay node are equipped with multiple antennas. In two-way relay channels, it is assumed that one terminal can eliminate its own self-interference but the other cannot. For this channel, we first maximize the sum-rate performance by employing an iterative gradient descent (GD) algorithm. Then, a simple singular value decomposition (SVD) based block triangularization is developed to null the self-interference. Simulation results show the proposed methods outperform the conventional schemes for various environments.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.11
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• pp.97-102
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• 2012

Recently, a wireless sensor network system has been receiving great attention for management of underground facilities. However, traditional wireless communication systems using microwaves in several hundred MHz ~ several GHz experience significant performance degradation in the non-uniform underground environment. In this research, in order to make a robust communication for the underground facilities, we propose a wireless underground sensor system based on magnetic field communication. In 3 meters underground environment including rocks, soils, water, etc.,, our proposed sensor network system has proved fully functional and met its performance specification.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.77-77
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• 2011

제주도는 본토와는 달리 유량 관측에 상당한 어려움이 있어 왔다. 투수성이 매우 높은 지반 특성으로 인해 6개의 하천을 제외하고 평시에 대부분 건천이거나 강우로 인한 유출 발생 시에도 급한 하상 경사와 짧은 유하거리 등의 수문지질학적 특성으로 강우 발생 1~2일 정도만 지속되어 유출의 측정 자체가 난해한 지역이다. 현재 16개 관측 지점에서 하천 유출 관측이 전자파 표면 유속계를 이용하여 실시되고 있으나 하천 전문 인력의 부족으로 인해 효과적인 관측자료의 해석, 운용 및 검보정 등에 어려움이 많았다. 본 연구는 국토환경부에서 발주한 제주형 물순환 관리기반 시스템 구축의 일환으로 제주도에 적합한 유량 측정 방식을 확립하고 유량 관측 지점을 증가시키고 기존 측정 자료를 검보정하는데 목적을 둔다. 우선 다양한 유량 계측 기법을 활용하여 상시하천에서 유량 관측을 실시하여 상호 비교하여 기존 방식으로 관측된 유량을 검보정하고 제주도 유출의 특성을 개괄적으로 파악하고자 한다. 사용된 유량 관측 기법으로 ADCP, LSPIV, 자기유속계, 전자파표면유속계가 연외천과 강정천에 동시에 적용되었다. ADCP는 유량 관측의 정확도가 다른 계측 기기보다 상대적으로 우수하다고 알려져 다양한 유량 관측 결과를 보정하는 기준으로 사용되었다. 하지만 홍수 유출의 경우 대부분의 현장에서 관측이 어려워 이 경우 LSPIV가 대안으로 채택이 되었다. 그리고 단면의 일부 지점에서 유속을 계측하는 자기 유속계와 전자파표면유속계로 유량을 계산하여 ADCP와 LSPIV의 유량과 비교하였다. 비교 분석 결과는 기존의 전자파표면유속계의 측정 오류를 보정하고 향후 제주형에 적합한 유량 측정 방식을 선정하는 데 사용될 것으로 기대된다.

• Journal of Biomedical Engineering Research
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• v.23 no.2
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• pp.101-107
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• 2002

This paper presents a segmentation algorithm to extract endocardial contour and epicardial contour of left ventricle in MR Cardiac images. The algorithm is based on a generalized gradient vector flow(GGVF) snake and a prediction of initial contour(PIC). Especially. the proposed algorithm uses physical characteristics of endocardial and epicardial contours, cross profile correlation matching(CPCM), and a mixed interpolation model. In the experiment, the proposed method is applied to short axis MR cardiac image set, which are obtained by Siemens, Medinus, and GE MRI Systems. The experimental results show that the proposed algorithm can extract acceptable epicardial and endocardial walls. We calculate quantitative parameters from the segmented results, which are displayed graphically. The segmented left vents role is visualized volumetrically by surface rendering. The proposed algorithm is implemented on Windows environment using Visual C ++.

• Journal of Internet Computing and Services
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• v.8 no.4
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• pp.17-29
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• 2007

This paper addresses a RNG based scatternet topology formation, self-healing, and routing path optimization for small-scale distributed environment, which is called RNG-FHR(Scatternet Formation, self-Healing and self-Routing path optimization) algorithm. We evaluated the algorithm using ns-2 and extensible Bluetoothsimulator called blueware to show that RNG-FHR does not have superior performance, but is simpler and more practical than any other distributed algorithms from the point of depolying the network in the small-scale distributed dynamic environment due to the exchange of fewer messages and local control. As a result, we realized that even though RNG-FHR is unlikely to be possible for deploying in large-scale environment, it surely can be deployed for performance and practical implementation in small-scale environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2087-2092
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• 2011

In this paper, we use the earth's magnetic field is measured by the MR device. By analyzing the measured data to determine the direction to implement the system. The construction of the system to determine the direction of neural networks, using input data based on an analysis of the relationship between pattern formation and characteristics of study and related information through a pattern when it is remembered that the output feedback input to associative networks and proves its feasibility for implementation. The entire detection system with regional changes in the Earth's magnetic field to adapt to the environment should aim to build a system.

• The KIPS Transactions:PartA
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• v.13A no.7 s.104
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• pp.623-632
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• 2006

We propose a peer-to-peer search scheme in which super peers with high rapacity constitute a ring by themselves and all peers utilize the ring for their query and publishing keys. In a dynamic peer-to-peer environment, the size of the super peer ring changes adaptively according to the changes of the system, but more powerful peers are continuously promoted to super peers. By simulations, we show that our proposed search scheme improves the query success rate of Gnutella+1hop replication search method, and maintains shorter query delay than JXTA as a static ring.

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1117-1124
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• 2010

The PM10 (Promethium 10) data is one of the important environmental data for measurement of the atmospheric condition of the country. In this article, the Autoregressive Error (ARE) model has been considered for analyzing the monthly PM10 data at the southern part of the Gyeonggi-Do, Suwon monitoring site in Korea. In the ARE model, six meteorological variables and four pollution variables are used as the explanatory variables for the PM10 data set. The six meteorological variables are daily maximum temperature, wind speed, relative humidity, rainfall, radiation, and amount of cloud. The four air pollution explanatory variables are sulfur dioxide ($SO_2$), nitrogen dioxide ($NO_2$), carbon monoxide (CO), and ozone ($O_3$). The result showed that the monthly ARE models explained about 13-49% for describing the PM10 concentration.