• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.409-409
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• 2017

유역단위에서 수문모델링을 수행함에 있어 토양수분은 물수지 관점에서 매우 중요한 인자로 고려된다. 더욱이, 최근 발생빈도가 커지고 있는 가뭄을 효과적으로 평가하고 예측하는 데에도 활용성이 매우 큰 것으로 인식되고 있다. 이러한 중요성에도 불구하고, 가용자료의 부족, 자료의 부정확성 등으로 인해 실제 유역모델링을 수행하는데 있어 활용도는 매우 적다. 이러한 점에서 본 연구에서는 동질성이 확보된 유역단위를 기준으로 다지점의 토양수분 자료를 추계학적으로 모의할 수 있는 기법을 개발하고자 한다. 토양함수자료는 지속성(persistence)이 매우 큰 특징을 가진다. 즉, 상태의 지속성이 크며 메모리가 오랫동안 유지된다는 점에서 추계학적 모의가 가능할 것으로 판단된다. 이러한 지속성을 이용함과 동시에 토양함수를 다양한 상태로 분리하고 이들 상태들간의 천이확률을 효과적으로 모의할 수 있다면 관측 토양함수 자료의 통계적 특성 재현이 가능하다. 본 연구에서는 용담댐 유역에 대해서 개발된 모형을 적용하고 활용성을 검토하고자 한다.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.60.3-60.3
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• 2019

한국천문연구원에서는 지난 2015년부터 남북한 천문분야 활성화 및 공동연구 기반 마련을 위한 연구를 수행하여 남북한 천문분야 협력 가능한 천문분야를 발굴하고 단계별 추진 방향을 제시하였다. 천문학은 과학기술분야 중 남북한 상호 신뢰 구축과 민족 동질성 회복에 기여할 수 있는 기초 학문으로, 과학기술계에서 남북협력 가능성이 높은 연구 분야로 평가받고 있다. 천문연은 남북 천문분야 학술 교류를 통한 남북한 천문분야 공동 발전, 남한 천문분야 기술이전을 통한 남북 균형 발전, 천문학 연구 범위 확대를 위한 남북한 협력 토대를 마련하기 위해 노력 중이다. 또한, 학술교류를 통한 공동연구 및 학술회의를 추진하고 있다. 그동안 수행했던 남북한 천문분야 협력 현황과 앞으로 방향 등에 대해 발표하고자 한다.

• Journal of Industrial Convergence
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• v.18 no.3
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• pp.19-25
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• 2020

In the software development process, software reliability evaluation is a very important issue. In particular, finding the optimal development model that satisfies high reliability is the more important task for software developers. For this, in this study, Pareto and Erlang life distributions were applied to the finite failure NHPP model to evaluate the reliability attributes. For this purpose, parametric estimation is applied to the maximum likelihood estimation method, and nonlinear equations are calculated using the bisection method. As a result, the Erlang model showed better performance than the Pareto model in the evaluation of the strength function and the mean value function. Also, as a result of inputting future mission time and evaluating reliability, the Erlang model showed an effectively high trend together with the Pareto model, while the Goel-Okumoto basic model showed a decreasing trend. In conclusion, the Erlang model is the best model among the proposed models. Through this study, it is expected that software developers will be able to use it as a basic guideline for exploring and evaluating the optimal software reliability model.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.433-433
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• 2022

수자원 관리를 위한 설계수문량의 산정은 수문자료의 통계적 특성을 고려한 빈도해석을 통해 이루어지며, 대상 관측지점에 대해 개별적으로 수행되는 지점빈도해석과 수문학적으로 동질하다고 판단되는 지점들의 자료를 동시에 고려하는 지역빈도해석으로 분류된다. 기후변화에 의한 미래 수문량의 변동성을 고려하기 위해 비정상성 빈도해석이 요구되나 짧은 기록을 갖는 수문자료로부터 정확한 변화 추세를 평가하기 어렵다. 이에 따라 지역빈도해석을 통해 자료를 확충함으로써 자료에 대한 신뢰성을 확보하고 지역 전체에 대해 대표성을 갖는 확률수문량을 산정하는 것이 합리적이다. 본 연구에서는 극치강수량의 지역빈도해석에서 비정상성을 고려하기 위해 단순선형회귀 모형을 통해 시간항에 대한 강수량의 경향성을 탐지하였다. 계층적 Bayesian 모형을 통해 Partial Pooling 기법을 적용함으로써 기존 L-모멘트 방법(complete pooling)에서 고려하지 못하는 개별지역의 강수 특성을 고려하였으며 불확실성을 정량화하였다. 한강 유역 18개 지점의 극치강수량에 대해 비정상성 평가 결과 대부분 지점에서 양의 기울기를 확인하였으며 미래 빈도별 확률강수량의 증가율을 제시한다.

• The Journal of Korean Association of Computer Education
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• v.17 no.4
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• pp.45-57
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• 2014

Many studies on algorithm judging system which verifies the correctness and the time efficiency of your program have been underway recently, most of which are on an online judging system focused on programming contests. However this study is mainly about development and application of the judging system based on client-server. Especially, we designed to promote metacognition and motivation which are emphasized in CRESST model, and implemented the total system that consists of the problem, data set, validation program, and user service environments. We applied our system to elementary, middle, and high school students, and We noticed a significant difference of average score between the experimental and control group in posttest and concluded that the teaching method using our system gave the bigger positive effects on programming learning.

• Journal of Gastric Cancer
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• v.9 no.4
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• pp.159-166
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• 2009

Purpose: We evaluated the efficacy and prognostic predictability of the $7^{th}$ UICC TNM classification compared to $6^{th}$ UICC TNM classification in patients with gastric cancer. Materials and Methods: Between June 1992 and December 2006, 1,633 patients with gastric cancer who had undergone gastric surgery and who had been analyzed by the $6^{th}$ UICC method were analyzed using the new $7^{th}$ UICC system. Results: Significant differences in 5-year survival rates were observed for $7^{th}$ UICC N0, N1, N2, N3a, and N3b compared to $6^{th}$ UICC. There were no significant differences in 5-year survival rates between T2 and T3. Distinct survival differences were present between stage III (IIIa, IIIb, and IIIc) and stage IV in $7^{th}$ UICC. Significant differences in 5-year survival rates were not expected for Ia versus Ib, Ib versus IIa, and IIb versus IIIa. The survival rates for the same stages were not homogeneously differentiated by $7^{th}$ UICC except for stage IV. Conclusion: The $7^{th}$ UICC classification system is not better able to predict patient survival compared to 6th UICC in patients with gastric cancer, but is better for accurate prognosis of patients with stage IV gastric cancer.

• Journal of Wetlands Research
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• v.12 no.3
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• pp.79-97
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• 2010

The purpose of this research is to apply the neural networks models for the hydrologic disaggregation of the yearly pan evaporation(PE) data in Republic of Korea. The neural networks models consist of multilayer perceptron neural networks model(MLP-NNM) and support vector machine neural networks model(SVM-NNM), respectively. And, for the evaluation of the neural networks models, they are composed of training and test performances, respectively. The three types of data such as the historic, the generated, and the mixed data are used for the training performance. The only historic data, however, is used for the testing performance. The application of MLP-NNM and SVM-NNM for the hydrologic disaggregation of nonlinear time series data is evaluated from results of this research. Four kinds of the statistical index for the evaluation are suggested; CC, RMSE, E, and AARE, respectively. Homogeneity test using ANOVA and Mann-Whitney U test, furthermore, is carried out for the observed and calculated monthly PE data. We can construct the credible monthly PE data from the hydrologic disaggregation of the yearly PE data, and the available data for the evaluation of irrigation and drainage networks system can be suggested.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.5
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• pp.933-940
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• 2024

In this study, an exponential family life distribution suitable for reliability analysis of system failures was applied to the NHPP-based software development model, and then the performance of models were newly evaluated by substituting the failure time data requested by the developer. First, as a result of analyzing the m(t) function that determines the model performance, all models showed the property of overestimating the ability to predict the true value. However, the Burr-Hatke-Exponential model, which showed the smallest error, was efficient. Second, the Lindley model was found to be the best when total evaluating the properties of the model performance (m(t), development cost, release time). Therefore, through this study, the performance of the exponential family life distribution was newly explored, and by utilizing related data, developers can identify required properties at an early stage and use them as basic reference data during the development testing phase.

• The Journal of the Acoustical Society of Korea
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• v.28 no.6
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• pp.534-541
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• 2009

Word recognition test (WRT) for the children can be useful for diagnosing the degree of communication disability, prescribing hearing instruments, planning aural rehabilitation and speech therapy, and determination of site of lesions. The Korean standard monosyllabic word lists for preschoolers (KS-MWL-P) were developed considering the criteria given by the literatures. However, the authors of KS-MWL-P suggested more children should be included to verify homogeneity of the lists using psychometric function curve since only 8 children participated in the developing process. The purpose of this study was to explore the homogeneity of KS-MWL-P for supplementing the limitations of the lists employing psychometric analysis. To 23 preschoolers who have normal-hearing, 100 monosyllabic KS-MWL-P words were examined with the pictures. Psychometric function curve with linear slopes of 20% and 80%'s correct rates through accounting recognition scores of each monosyllabic word at variable intensities from -10 to 40 dBHL was obtained and analyzed. As a result, s-shaped psychometric function curve was presented with increasing correct rate depending on intensity and showed no statistical significant differences among each word and list. The congruous graph shapes among lists also indicated good homogeneity and the list 1,2,3,4's average slopes were 4.48, 3.86, 4.65, 4.50. It was verified that the homogeneity was suitable because the analysis of variance showed no statistical significance among lists (p>0.05). However, KS-MWL-P's order of slope according to the order of the number of items, $1{\sim}10$, $1{\sim}20$, $1{\sim}25$ showed no difference with the p-value of 0.93, 0.59, 0.91, 0.70 for the lists 1,2,3, and 4, respectively. Although KS-MWL-P was assumed that the lower-numbered items were easy for testing younger ages, this study's results could not agree with the author's conclusion. Considering this matter, rearranging of the number of items should be performed according to the analysis of slope suggested by this study for testing younger children with easier items. Other than this, in conclusion, KS-MWL-P was proved to be useful for clinical and rehabilitative evaluating and training tools for preschoolers.

• Communications of Mathematical Education
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• v.28 no.1
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• pp.131-154
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• 2014

The purpose of this study was to examine the effect of essay writing-centered mathematics instruction on problem solving and mathematical deposition in the elementary school. For the present study, two 6th grade classes with equivalent achievement in terms of problem solving and mathematical disposition based on the pretest. A total of 15 mathematics lessons focused on writing activities were administered to the experiment group for two months, while the textbook-based traditional lessons were given to the comparison group. Both quantitative and qualitative methods were adopted to analyze the data. The results of the present study showed that essay writing-centered mathematics teaching is statistically superior that the textbook-based mathematics teaching with respect to students' problem solving and mathematical disposition. In addition, it was evidenced that essay writing-centered mathematics instruction makes an influence on students' perceptions toward essay-based assessment in a positive way.