• Journal of the Korean Society for information Management
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• v.24 no.3
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• pp.343-362
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• 2007

The purpose of this study is to design and implement an ontology-based retrieval system for the electronic records of universities and to compare its performance with the existing keyword-based retrieval system. We used OntoStudio 1.4 for implementing an ontology-based retrieval system, and the test collection consisted of the following: (1) 5,099 electronic records of the 'personnel management notification' created by Korea Maritime University, (2) 20 topics (10 short-topics and 10 long-topics), and (3) the relevant assessments were conducted by the group of human experts. 10 university staff participated in the experiment of keyword-based searching and used the same test collection as used in the experiment of ontology-based searching. The ontology-based retrieval system outperformed to the keyword-based retrieval system in terms of Recall and Precision, and the same results showed in the test of the short-topics and long-topics comparison.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.583-591
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• 2011

Accurate observation results of dynamic displacements are essential to the protection of civil structures. In this study, we evaluated the optimal methods of the RTK/GPS Accelerometer integration through comparison and analysis of several experiments results. Two methods will be used to calculate the dynamic displacements from the results of the acceleration data as well as two integration methods for measuring the dynamic, static, and quasi-static displacements by incorporating the displacement results from the RTK-GPS and Accelerometer. By using a Cantilever Beam and LVDT measurement, we were able to ensure that the different displacement comparisons would be reliable and accurate. As a results from experiments, the accelerometer processing method applied by use of accelerometers data was filtering with the double integral using FIR band-pass filter which is most optimal for assessing the dynamic displacements. Also, the integrated method using extracting substitution displacements is suitable for measuring synthetically the dynamic static and quasi-static displacements of civil structures with RTK-GPS and accelerometer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1511-1517
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• 2014

Based on the simulation model for phase noise effect, the phase noise performance of communication system using the M-ary APSK modulation method is analyzed in this paper. The phase noise effects for APSK higher order modulation method are modeled by considering the signal constellations of the modulation methods. The simulation model is verified by comparing the analytic results for lower order modulation signals with simulated results for those modulation signals. Based on the simulation model, then, the phase noise effects for M-ary APSK are analyzed. The simulated results for PSK lower order modulation signals are in agreement with the results by the analytic model in the order of 1 %. The proper phase noise effects for M-ary APSK modulation signals are deduced by the simulation model. Also, the required signal-to-noise ratios of phase noise are proposed for phase noise degradations, which are used as the design parameter that considers the phase noise effect.

• Journal of the HCI Society of Korea
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• v.7 no.2
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• pp.35-42
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• 2012

The purpose of this study was to evaluate the usability of the tablet PC-based Korean high-tech AAC(Augmentative Alternative Communication System) software. In order to develop an AAC software which is appropriate to Korean cultural/linguistic contexts and communication needs of the users, we examined the necessity and ease of use for the communication functions that are required in native Korean communication, such as polite expressions, tense expressions, negative expressions, subject-verb auto-matching, and automatic sentence generation functions, using a scenario-based user testing. We also investigated the users' needs, preferences, and satisfaction for the tablet PC-based Korean high tech AAC using a semi-structured and open questionnaires. The participants of this study were 9 special education teachers, 6 speech therapists, and 6 parents whose children had communication disabilities. The results of the usability testing of the tablet PC-based Korean high-tech AAC software presented positive responses in general, by indicating overall scores of above 4 out of 5 except in tense and negative expressions. The necessity and ease of use in the tense and negative expressions were evaluated relatively low, and it might be related to the inconsistent interface with the polite expressions. In terms of the user interface(UI), there were users' needs for clear visual feedback in the symbol selection and display, consistent interface for all functions, more natural subject-verb auto-matching, and spacing in the text within symbols. The results of the usability testing and users' feedback might serve as a guideline to compensate and improve the function and UI of the existing AAC software.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1558-1562
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• 2007

우리나라 지형은 전체의 70%가 산지로 이루어져 있다. 특히 강원도 지역과 같이 산지가 대부분인 지역에서는 경사도에 따라 강우에 의한 유출특성이 크게 달라질 수 있으므로 지형의 경사가 고려된 유출량 산정방식이 필요하다. 현재 유출량 산정 방식에 많이 이용되고 있는 SCS의 CN값은 미국의 중서부 지역과 같이 경사도 5%미만인 지역에서의 유출량 산정에 적합한 유출곡선지수이다. 경사도 5%에서 유출량 산정에 적합한 CN값을 우리나라의 강원도 지형과 같이 복잡하고 경사도가 심한 지역에 적용하기에는 부적합하다. 따라서 본 연구에서는 연구대상지역인 도암댐 유역의 평균 25.8% 경사도를 고려한 직접유출량을 산정하여 기존 평균 경사도 5%일 때의 직접유출량과 비교분석하였다. 본 연구의 비교분석에 있어서 직접유출의 모의가 가능한 Long-Term Hydrologic Impact Assessment (L-THIA) ArcView GIS 모델을 사용하였고 모델의 적용성 평가를 위해 수문분석에 사용되고 있는 WHAT 모듈을 이용하여 분리된 직접유출과 비교하였다. 그 결과 유출량 산정을 위해 CN값 산정시 강원도 지형과 같이 지형이 복잡하고 경사가 심한 지형에 있어서는 유역의 경사도를 고려하여 유출을 모의해야 한다는 것을 알 수 있다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.165-172
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• 2015

The appropriateness of railway route design is generally evaluated by the future value corresponding to the travel demand or benefit-cost analysis. These methods may have the limitation for the reasons that all the design alternatives cannot be considered, and the differentiation between the alternatives may not be significant because the alternatives are based on the strict basic scheme such as the design criteria. In addition, the cost varies by the design elements. In this study, all the design alternatives are considered with the automatized tool and the design criteria, and evaluated with the multi-criterion decision making method. The weight for each design element with the analytic hierarchical process may be helpful to derive more efficient railway alignment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.4
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• pp.8-15
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• 2009

In this paper, a new demand-side evaluation for the technical potential of lighting dimming control and its applications in electricity markets have been presented. The California standard practice test has been widely used to estimate the economic value of demand-side resources. However, as the advent of deregulation and restructuring of power industry, the California test has been facing some limitations to adopt in the new market environments. In particular the conventional DC test is appropriate for the traditional vertically integrated utility, not for the restructured unbundled utility. Thus, this paper presents a new method to evaluate the economic value of demand-side resource, especially of controllable lighting dimming resource in terms of the energy service provider in market environments. We, therefore, first estimate the technical potential of the lighting dimming control and evaluate the value of the lighting dimming control based on the Korean electricity market data in 2006. The study result shows that the lighting dimming control is a cost effective option for the energy service provider.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.293-293
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• 2021

자연유량이란 인위적 행위에 의한 하천의 유량 변화가 없는 개발되지 않은 상태의 하천유량을 말하며, 실제 유량을 측정하거나 관측자료를 활용한 장기유출모형을 통해 산정할 수 있다. 미계측 유역에 대한 강우-유출 모형 구축시, 무엇보다 실제 미계측유역에 적용시 나타날 수 있는 문제점을 최소화할 수 있는 방향으로 모형 개발이 이루어지는 것이 필요하다. 강우-유출 모형 매개변수의 수가 많아질수록 과적합(over-fitting)의 발생 소지가 증가하게 되며, 지역화 모형 구축시 불확실성을 더욱 가중시키게 된다. 이러한 이유로, 모형의 검정보다는 검증에 초점이 맞춰져 있어야 하며, 더불어 사용되는 강우-유출 모형의 매개변수가 적어야 한다. 본 연구에서는 대표 강우-유출모형의 선정시 여러 평가 기준 중 예측의 정확성 측면에서 통계적 지표를 통해 모형의 수행능력에 중점을 두었으며, 적은 개수의 매개변수를 갖음에도 불구하고 상대적 우수한 모의결과를 제공하는 GR4J(Ge'nie Rural a 4 parame tres Journalier)모형을 최적 유출모형으로 선정하여 댐 상류유역에 대한 자연유량 재현성능을 평가하였다. 최종적으로 강우-유출모형의 최적매개변수와 유역특성인자 사이의 상호연관성을 고려해 매개변수를 지역화하기 위하여, 본 연구에서는 두 가지 이상의 변량에 대한 상관성을 효과적으로 재현하는데 효과적이며, 자유로운 주변확률분포 선택과 결합확률분포의 추정이 용이한 장점이 있는 Copula 함수를 활용하였다. 제시된 방법론에 대한 적합성을 평가하기 위해 교차검증 관점에서 지역화된 매개변수의 적합성을 검토하였으며, 본 연구에서 도출된 결과는 유역특성에 따른 미계측유역의 자연유량 산정시 지역 매개변수를 강우-유출모형에 활용함으로써 신뢰성 있는 자연유량 산정 결과를 제공할 수 있을 것으로 판단된다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10c
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• pp.191-194
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• 2007

본 논문에서는 분산형 환경에 적합한 새로운 의사결정나무 알고리즘을 제안하고 그 실용성을 확인하기 위해 분산형 데이터마이닝 시스템을 구현하였다. 그리고 본 논문에서 구현한 시스템을 평가하기 위해 데이터의 신뢰성이 높은 방대한 양의 미국의 인구통계 데이터(Census bureau database)를 사용하였다. 본 논문에서 구현한 시스템을 이용하여 신뢰성을 테스트하였고 그 결과가 다른 시스템의 알고리즘과 유사한 신뢰성을 나타내었다.

• Journal of KIISE
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• v.45 no.1
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• pp.76-85
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• 2018

Governments and public agencies try to use the cloud to carry out their work and provide public services. However, a public cloud is vulnerable to security side because it has a structure to support services using public networks (i.e, the internet). Thus, this paper finds the general security vulnerabilities of a network and compares and analyzes the characteristics of transport protocols (UDP, TCP, SCTP, and MPTCP) on the basis of their security vulnerabilities. This paper uses a reliability and security factor for the comparative analysis, evaluates the security exposure, and chooses a suitable protocol considering the security of the transport protocols in the cloud circumstance.