• Journal of the Korea Society for Simulation
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• v.33 no.1
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• pp.19-26
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• 2024

The phase-type, PH, distribution is defined as the time to absorption into a terminal state in a continuous-time Markov chain. As the PH distribution includes family of exponential distributions, it has been widely used in stochastic models. Since the PH distribution is represented and generated by an initial probability vector and a generator matrix which is called the Markovian representation, we need to find a vector and a matrix that are consistent with given set of moments if we want simulate a PH distribution. In this paper, we propose an approach to simulate a PH distribution based on distribution function which can be obtained directly from moments. For the simulation of PH distribution of order 2, closed-form formula and streamlined procedures are given based on the Jordan decomposition and the minimal Laplace transform which is computationally more efficient than the moment matching methods for the Markovian representation. Our approach can be used more effectively than the Markovian representation in generating higher order PH distribution in queueing network simulation.

• Journal of the Korea Computer Graphics Society
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• v.2 no.1
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• pp.1-6
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• 1996

In ray tracing of 3D volume data, the color of each pixel in the image is typically obtained by accumulating the contributions of sample points on the ray cast from the pixel point. This accumulation is most naturally represented by integration. In most methods, however, it is done by numerical summation because analytical solution to the integration are hard to find. This paper shows that a semi-analytical solution can be obtained for a typical ray tracing of volume data. Tentative conclusions about the significance and usefulness of our approach are presented based on our experiments.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.81-87
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• 2022

In this paper, we propose diffraction-based sound control method to improve sound immersion in a virtual environment. The proposed technique can express the wave and flow of sound in a physical environment and a pattern similar to diffraction in real-time. Our approach determines whether there is an obstacle from the location of the sound source and then calculates the position of the new sound reflected and diffracted by the obstacle. Based on ray tracing, it determines whether or not it collides with an obstacle, and predicts the sound level of the agent behind the obstacle by using the vector reflected and refraction by the collision. In this process, the sound attenuation according to the distance/material is modeled by attenuating the size of the sound according to the number of reflected/refracted rays. As a result, the diffraction pattern expressed in the physics-based approach was expressed in real time, and it shows that the diffraction pattern also changes as the position of the obstacle is changed, thereby showing the result of naturally spreading the size of the sound. The proposed method restores the diffusion and diffraction characteristics of sound expressed in real life almost similarly.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.456-466
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• 2014

This is a study of George Lindbeck's postliberalism that views religion as a cultural-linguistic approach. Knowing that the conceptual-propositional approach of the traditional Christian theology and the experiential-expressive approach of liberalism cannot be a solution for the post-modem religious phenomenon, George Lindbeck proposes an alternative. He proposes a cultural-linguistic approach to overcome the previous approaches. The first insight of Lindbeck's postliberalism is to understand religion as culture or language, because human beings become acquainted with a religion as they learn a language. The second insight comes out of the first, to understand doctrine as grammar. If we understand religion and doctrine this way the troubles and conflicts among religions will be resolved naturally, because each religion can be interpreted in its own system just as a language cannot be said to be good or bad, right or wrong. This approach makes several contributions as follows: it promotes a dialogue among religions, it emphasizes practice; and it preserves the Bible as an authoritative theological text. However it also brings many limitations as follows: it emphasizes the church's interpretation rather than the text's own interpretation; it views the truth simply as coherence; it promotes radical relativism and elitism; and through theological eschatology he makes his theory return to a propositionalism. Accordingly, the researcher concludes that Lindbeck's cultural-linguistic theory of religion is not an alternative that overcomes the limitations of theological conservativism and liberalism.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.191-201
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• 2014

The purpose of this study is to propose strategies of puzzle-based learning for Informatics gifted education through analyzing Informatics gifted elementary students' computational problem solving approaches in puzzle-based learning contexts. Six types of educational puzzles, which are constraints, optimization, probability, statistically speaking, pattern recognition, and strategy, were used in teaching 14 Informatics gifted students for 8 sessions. The results of pre and post test and each students' answers were analyzed to identify why students were not able to solve the puzzles. We also analysed what essential computational strategies are needed to solve each type of puzzles, and what students did not know in solving puzzle problems. We identified some problems caused by puzzle representation methods, and various students' intuitions that disturb puzzle solving. Also, we identified essential computational strategies to solve puzzles: backtracking, dynamic programming, abstraction, modeling, and reduction of big problem. However, students had difficulties in applying these strategies to solve their puzzle problems. We proposed the revised puzzle-based learning strategies, which is based on the improved problem representation, just-in-time cognitive feedbacks, and web-based learning system.

• Journal of the Korean School Mathematics Society
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• v.3 no.1
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• pp.211-217
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• 2000

본 논문의 목적은 G. Cantor 에 의하여 출발된 집합론을 보통집합 이론이라고 구별하여 부를 때, 보통 집합 이론이 그 바탕에 깔고 있는 논리적 제한 점들 곧, 배중률이라든지 모순의 법칙 등을 어떻게 보완할 수 있을 것인가\ulcorner 하는 점과 그러한 점을 보완하여야 할 필요성에 대하여도 생각하고자 한다. 그런 관점에서 보통집합 이론과 퍼지집합 이론의 기본개념을 상호 비교함으로써 앞서 제기한 문제의 보완 요소를 찾아보려고 한다. 실제에 있어 인간의 사고 가운데에서는 중간을 배제하는 일이 없음에도 불구하고 이를 수학적으로 접근하고 표현하는 수단이 부족함으로 인하여 부자연스러운 논리의 법칙을 받아들일 수밖에 없었던 것도 사실이다. 특히, 논리적 응용력이 부족한 중등과정의 학생들에게 있어서 수학이 전적으로 2가 논리에 의하여 지배되고 있다는 방식으로만 지도하는 것은 여러 가지 측면에서 그 내용의 보완이 요구된다. 보다 다양한 수학적 표현의 여지를 열어주는 지도법은 쉼없이 연구되어야 할 것이다. 무엇보다도 배우는 학생들이 보다 폭 넓은 사고의 영역을 소유하고, 그를 바탕으로 창의적이고 자유로운 발상이 이어 질 수 있도록 하기 위하여는 교사의 수학적 시야가 보다 넓고 유연해져야 한다함은 재론할 필요가 없을 것이다. 그런 의미에서 본 논문이 작은 역할을 할 수 있기를 바란다.

• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.405-418
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• 2018

This paper was carried out to provide basic data for career search of the free school system. Putting the goal of career education into cultivating expertise, the review was made on the results of the previous studies on the requirements of professional practice. However, As the controversy over the requirements of professional practice has not been solved, so the core elements related to expert performance were examined as a whole through a fundamental cognitive mechanism from which diverse human cognitive characteristics appear. The results show that expert domains consists of content and representation that can exist in an integrated to a great variety of combinations between the two or independent manner, and each domain or field expert performance require different levels of the elements such as intelligence, internal thinking, curiosity (motivation), and obsession (task commitment); and the birth of 1% experts in a domain or field is determined by the obsession. Based on the results, this paper discusses issues related to professionalism and provides a concrete approach to career search during the free semester.

• Journal of the Korean Society for Library and Information Science
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• v.51 no.4
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• pp.121-138
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• 2017

As information users seek multimedia with a wide variety of information needs, information environments for multimedia have been developed drastically. More specifically, as seeking multimedia with emotional access points has been popular, the needs for indexing in terms of abstract concepts including emotions have grown. This study aims to analyze the index terms extracted from Getty Image Bank. Five basic emotion terms, which are sadness, love, horror, happiness, anger, were used when collected the indexing terms. A total 22,675 index terms were used for this study. The data are three sets; entire emotion, positive emotion, and negative emotion. For these three data sets, co-word occurrence matrices were created and visualized in weighted network with PNNC clusters. The entire emotion network demonstrates three clusters and 20 sub-clusters. On the other hand, positive emotion network and negative emotion network show 10 clusters, respectively. The results point out three elements for next generation of multimedia retrieval: (1) the analysis on index terms for emotions shown in people on image, (2) the relationship between connotative term and denotative term and possibility for inferring connotative terms from denotative terms using the relationship, and (3) the significance of thesaurus on connotative term in order to expand related terms or synonyms for better access points.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.10a
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• pp.43-43
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• 1993

항공기 일정계획문제는 항공기, 승무원, 항공기 정비, 공항사용 등의 현재흐름을 시간과 공간의 개념을 도입한 Network상에 표현하여 분석하는 문제로서 여러가지 의사결정이 복합적으로 관련되어 있는 문제이다. 기존 연구에서는 운영상에 발생하는 많은 제약조건을 주어진 가정으로 처리하여 비교적 단순한 수리모형으로 최적해를 구하고자 했으므로 실제 적용에 한계를 가지고 있다. 또한, 최적해법으로 사용했던 최대흐름 알고리즘(Maximum Flow Algorithm)이나 단계적 접근법(Sequential Approach)으로는 변수의 수가 증가함에 따른 해법의 한계점을 가지고 있다. 본 연구에서는 1978년 미국의 항공규제완화 조치 후 많이 사용되고 있는 Hub and Spoke 노선상에서 항공기를 할당하는 문제로서, 보다 현실적인 제약요인을 포함하는 수리모형을 수립하고, Lagrangean Relaxation 기법을 사용하여 해를 구하고자 하였다.

• The Journal of Information Technology and Database
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• v.2 no.2
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• pp.35-54
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• 1995

회계시스템에 데이타베이스시스템을 도입하는 연구의 주류는 데이타베이스 분야에서 개발된 데이타모형(data mood)을 이용한 회계 데이타모형의 개발에 있었다. 본 연구의 목적은 데이타베이스 분야에서 최근 개발되어 널리 보급되고 있는 객체지향 데이타모형을 적용한 회계 데이타모형(Object-oriented Accounting Data Model; OADM)을 개발하고 응용하는 데 있다. OADM은 회계시스템의 정보제공능력 제고 및 시스템통합의 과제를 해결하는 데 유용한 도구가 될 것이다. OADM은 데이타모형 관점에서 규명된 전통적 회계시스템의 본질을 모형화의 배경으로, REA 모델을 모형화의 기초로, 그리고 객체지향 데이타모형을 모형화의 도구로하여 개발된다. 회계 데이타모형화에 있어서 복합적인 회계데이타의 표현, 복합적이고 까다로운 회계처리절차의 데이타화, 타부문과의 연계, 회계시스템의 변경 및 확장 등의 제 문제점은 기존의 데이타모형으로는 해결하기가 어려우나 객체지향 데이타모형을 회계 데이타모형화에 도입함으로써 이러한 문제점을 해결할 수 있다. 본 연구와 관련한 후행 연구로는 활동중심 원가계산의 모형화, 예산시스템의 모형화 그리고 사무정보시스템의 모형화 등을 들 수 있다. OADM은 이러한 모형화의 기초로 이용될 수 있다. 모형의 실증분석도 가치 있는 미래연구로 본다.