• Journal of the Institute of Convergence Signal Processing
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• v.19 no.4
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• pp.147-152
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• 2018

Underwater transient signals are complex, variable and nonlinear, resulting in a difficulty in accurate modeling with reference patterns. We analyze one type of underwater transient signals, in the form of whale sounds, using the MFCC(Mel-Frequency Cepstral Constant) and synthesize them from the MFCC and the weighted $L_2$-norm minimization techniques. The whales in this experiments are Humpback whales, Right whales, Blue whales, Gray whales, Minke whales. The 20th MFCC coefficients are extracted from the original signals using the MATLAB programming and reconstructed using the weighted $L_2$-norm minimization with the inverse MFCC. Finally, we could find the optimum weighted factor, 3~4 for reconstruction of whale sounds.

• Convergence Security Journal
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• v.21 no.2
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• pp.47-56
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• 2021

Network topology visualization has been studied a lot since the past and developed with many tools. The network topology has strength in understanding the overall structure of a network physically and is useful for understanding data flow between nodes logically. Although there are existing tools, not many can be utilized efficiently while using the general network node data structure and express the topology similar to the actual network structure. In this paper, we propose an efficient method to visualize topology using only connection information of network nodes. The method finds the central node by using the centrality, the influence of nodes in the network, and visualizes the topology by dynamically segmenting all nodes and placing network nodes in 3D space using the weight of the child node. It is a straightforward method, yet it effectively visualizes in the form of an actual network structure.

• Tunnel and Underground Space
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• v.31 no.4
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• pp.211-220
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• 2021

Tunnel collapse often occurs during deep underground tunneling (> 40 m depth) in South Korea. Natural cavities as well as water supply pipes, sewer pipes, electric power cables, artificial cavities created by subway construction are complexly distributed in the artificial ground in the shallow depths of the urban area. For deep tunnel excavation, it is necessary to understand the properties of the ground which is characterized by porous elements and various geological structures, and their influence on the stability of the ground. This study analyzed geological factors for risk assessment in deep excavation in South Korea based on domestic and overseas case study. As a result, a total of 7 categories and 38 factors were derived. Factors with high weights were fault and fault clay, differential stress, rock type, groundwater and mud inrush, uniaxial compressive strength, cross-sectional area of tunnel, overburden thickness, karst and valley terrain, fold, limestone alternation, fluctuation of groundwater table, tunnel depth, dyke, RQD, joint characteristics, anisotropy, rockburst and so forth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.1
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• pp.128-133
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• 2022

This paper deals with the graph in which the weights of edges are given the distances between two end vertices on a metric space. In particular, we will study about a path P with n vertices for these graphs. We obtain a new graph $\bar{P}$ by augmenting an edge to P. Then the length of the shortest path between two vertices on $\bar{P}$ is considered and we focus on the maximum of these lengths. This maximum is called the diameter of the graph $\bar{P}$. We wish to find the augmented edge to minimize the diameter of $\bar{P}$. Especially, for an arbitrary real number λ > 0, we should determine whether the diameter of $\bar{P}$ is less than or equal to λ and we propose an O(n)-time algorithm for this problem, which improves on the time complexity O(nlogn) previously known. Using this decision algorithm, for the length D of P, we provide an O(nlogD)-time algorithm to find the minimum of the diameter of $\bar{P}$.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.104-104
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• 2022

임진강 수계는 북측 지역이 다수를 차지하는 유역 특성으로 예고 없는 상류 급방류, 강우 등으로 인해 댐 운영에 근본적 어려움이 있으며, 이에 따라 홍수조절지 및 댐 하류 계측 가능 지역의 취득 자료를 고려한 하천 수위 변화에 대한 사전 예측을 필요로 하고 있다. 홍수기 하천 도달시간 및 수위예측 기법으로는 물리 기반 및 데이터 기반 모델들이 다양하게 연구되어 왔으며, 일부 연구성과들은 현업에 활용하고 있다. 물리기반 모델은 하천 지형 변화에 대한 자료 취득 및 분석에 많은 시간을 요하는 단점은 있으나, 설명 가능한 모델을 구현할 수 있을 것으로 사료 된다. 반면, 데이터 기반 인공지능 모델은 짧은 시간 및 비용으로 모델을 개발할 수 있으나, 복잡한 알고리즘구현 시 설명이 불가하여 일관성을 의심 받을 수 있다. 본 논문에서는 홍수 도달시간과 하류 수위 상승에 대하여 설명 가능한 인공지능 알고리즘 및 시뮬레이션 프로그램을 개발하고자 하였다. 홍수 도달시간 예측은 기존 조견표 방식에서 고려하지 않았던 홍수파의 영향을 추가 변수화 하고, 데이터의 전후처리를 통하여 도달시간을 예측하였다. 실시간 하류 수위 예측은 댐 방류량, 주변 강우, 조위 등을 고려하여 도달시간 후 수위를 예측할 수 있도록 구현하였으며, 자료 동화 기술을 일부 적용하였다. 미래 방류조건에 대한 시뮬레이션을 위해서는 미래 방류량, 예상 강우 입력 시 하천 지점별 수위 상승을 예측할 수 있도록 알고리즘 및 프로그램을 개발하였다. 이를 구현하기 위하여 다양한 인공지능 알고리즘을 이용한 학습, 유전자 알고리즘을 이용한 가중치 학습 제한 조건내 최적화, 수위파와 조위파의 중첩의 정리 등을 이용하여 예측 정확도 및 신뢰성을 제고 하였다. 인공지능 분석결과의 현업활용성 제고를 위하여 시뮬레이터 프로그램을 개발하여 현업에 적용하였다.

• The Korean Journal of Applied Statistics
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• v.37 no.2
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• pp.157-176
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• 2024

Integrative analysis for better understanding of complex biological systems gains more attention. Observing subjects from various perspectives and conducting integrative analysis of those multiple datasets enables a deeper understanding of the subject. In this paper, we compared two methods that simultaneously consider two datasets gathered from the same objects, canonical correlation analysis (CCA) and co-inertia analysis (CIA). Since CCA cannot handle the case when the data exhibit high-dimensionality, two strategies were considered instead: Utilization of a ridge constant (CCA-ridge) and substitution of covariance matrices of each data to identity matrix and then applying penalized singular value decomposition (CCA-PMD). To illustrate CIA and CCA, both extensions of CCA and CIA were applied to NCI60 cell line data. It is shown that both methods yield biologically meaningful and significant results by identifying important genes that enhance our comprehension of the data. Their results shows some dissimilarities arisen from the different criteria used to measure the relationship between two sets of data in each method. Additionally, CIA exhibits variations dependent on the weight matrices employed.

• Information Systems Review
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• v.25 no.2
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• pp.145-162
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• 2023

Asset management is a complex and difficult field that requires insight into numerous variables and even human psychology. Thus, it has traditionally been the domain of professionals, and these services have been expensive to obtain. Changes are taking place in these markets, and the driving force is the digital revolution, so-called the fourth industrial revolution. Among them, the Robo-Advisor service using artificial intelligence technology is the highlight. The reason is that it is possible to popularize investment advisory services with convenient accessibility and low cost. This study aims to clarify what factors are critically important when selecting robo-advisors for service users and providers in Korea, and what perception differences exist in the selection factors between user and provider groups. The framework of the study was based on the marketing mix 4C model, and the design and analysis of the model used Delphi survey and AHP. Through the study design, 4 main criteria and 15 sub-criteria were derived, and the findings of the study are as follows. First, the importance of the four main criteria was in the order of customer needs > customer convenience > customer cost > customer communication for both groups. Second, looking at the 15 sub-criteria, it was found that investment purpose coverage, investment propensity coverage, fee level and accessibility factors were the most important. Third, when comparing between groups, the user group found that the fee level and accessibility factors were the most important, and the provider group recognized the investment purpose coverage and investment propensity coverage factors as important. This study derived useful implications in practice. First, when designing for the spread of the robo-advisor service, the basis for constructing a user-oriented system was prepared by considering the priority of importance according to the weight difference between the four main criteria and the 15 sub-criteria. In addition, the difference in priority of each sub-criteria shown in the group comparison and the cause of the sub-criteria with large weight differences were identified. In addition, it was suggested that it is very important to form a consensus to resolve the difference in perception of factors between those in charge of strategy and marketing and system development within the provider group. Academically, it is meaningful in that it is an early study that presented various perspectives and perspectives by deriving a number of robo-advisor selection factors. Through the findings of this study, it is expected that a successful user-oriented robo-advisor system can be built and spread in Korea to help users.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.135-145
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• 2016

In Korea, a series of noise-reduced aluminum forms are being recently used in apartment housing construction. However, their complicated and time-consuming work processes, and the noise which is still generated due to the inherent property of aluminum when especially installing and dismantling them have been pointed out as a problem to be certainly solved for increasing their practical use in construction sites. The primary objectives of this study are proposing an optimal conceptual design of a newly designed noise-reduced aluminum form and verifying the technical feasibility by conducting a working mock-up drive experiment. Thus, conventional noise-reduced aluminum forms have been analyzed and three conceptual designs of a newly noise-reduced aluminum forms have been deducted. AHP has been applied to a survey data collected by interviewing field experts. A trade-off analysis results have shown that 'Noise-reduced System Aluminum Form with a Drop-down Floor Post and Adaptive Beam' the highest weights of safety(0.52), work convenience(0.54) and thus selected. The suggested conceptual design in this study improved problems of conventional system aluminum forms. It is also expected that the suggested design will be used as a reliable guideline for the actual development of an aluminum form that ensures noise-reduce, work convenience and labor safety.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.1087-1094
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• 2009

As online community was revitalized, the internet became the second space for people's everyday life. People enter into a connection with other on-line members and they maintain and extend their relationships. Such relationships can be analyzed and visualized with social network analysis. The method oftentimes envisions the structural elements of complex social life. The study aims at visualizing the relationships among the Cyworld users and designs an application "Blow Blow Your Pinwheel", the main purpose of this application is visualizing social relationships between ego and '1chons' which is a concept of friendship in Cyworld. Designing such an application, the study focuses on closeness of relationships which we think is composed of 1)proximity 2)similarity, 3)familiarity, and 4)reciprocity. The study used these concepts in measuring the strength of relationship between ego and other 1chons(friends). Specifically, we devised survey questionnaires which asked users to evaluate the importance of the above factors of closeness, and implemented the result in calculating the strength of the relationship between ego and other by giving weights for each factor. These measurements then were applied in visualizing the relationships in the application, we designed. Through the application, we can compare on-line relationships with off-line relationships and attempt for the new approach of Social Networks.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.425-428
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• 1996

본 연구에서는 기존문헌에서 논의되어온 수리적 매체선택모형의 한계점을 고려하여 의사결정자에게 유용한 매체선택지침을 제공할 수 있는 모형을 구축하고 이를 실제사례에 적용하여 모형의 현실적용성을 살펴본다. 기존의 매체선택모형들은 가정의 현실성 결여와 특정 요인의 단편적 고려 등으로 인하여 실행상의 문제점을 노출하였다. 최근 매체의 이미지, 소비자에 대한 소구, 편집항목 등 매체현상과 관련된 정성적 요소들을 고려하고자 하는 의도에서 AHP를 매체선택 문제에 활용하고 있으며 이것은 매체선택모형을 보다 현실적인 모형으로 만들고 있다. 또한 AHP에 의해 도출된 매체의 선호정도를 독립적으로 이용하는 것보다 정량적인 요소를 고려한 수리적 모형과 결합하는 것이 보다 효과적인 것으로 이해되고 있으며 이는 매체선택모형의 현실적합성을 한층 증가시키고 있다고 할 수 있다. 이러한 정성적 요소와 정량적 요소를 결합한 매체선택모형은 다양한 의사결정요소들을 모형에 포함시켰다는 의미에서 기존의 모형들과 차별화가 이루어지나 실제 모형을 적용하여 그 효과를 판단하는 것은 광고의 복잡성과 측정상의 문제로 인해서 매우 어려운 일로 보인다. 따라서 매체선택 모형은 더 이상 장량적인 관점에서 최적해를 추구하기 보다는 모형이 광고의 상황과 기업의 전략등에 얼마나 효과적으로 대처하는가에 초점을 맞추는 것이 중요하다. 이에 따라 본 연구에서는 AHP와 정수계획법을 결합한 모형을 이용하여 고려하고자하는 매체선택 관련요소들을 체계화하고 이 모형이 최적해를 산출하는 모형으로서가 아니라 의사결정자에게 매체선택지침을 제시하는 하나의 현실적인 의사결정지원도구로서 역할을 하고 있는가에 초점을 맞춘다. (4) 교수-학생간의 인간적인 관계, (5) 숙제 및 과제물과 같은 5가지의 요인으로 구성되어진 것으로 분석되었다. 특히 한국학생을 대상으로 하여 AHP를 이용하여 각 요인들의 수업효과에 대한 상대적 가중치를 조사하였다. 특이한 결과는, 미국학생의 경우 수업준비 및 강의 방법이 상대적으로 중시된 반면, 한국학생들은 미국학생들이 비교적 덜 중시하는 교수-학생간의 인간적인 관계가 수업효과를 높이는데 가장 큰 기여를 하는 것으로 나타났다. 본 연구는 한국 문화의 특징이라 할 수 있는 교수-학생간의 인간적인 관계가 중시되는 교육환경하에서, 정보화 사회의 한 수업형태인 재택수업을 외국(특히 미국)의 방법을 그대로 따라 실시할 경우, 많은 부작용이 있을 수 있다는 것을 암시하며, 따라서 우리 교육문화에 맞는 재택수업 형태의 개발이 시급함을 제시한다고 하겠다.column density of HCaN is (1-3):n1014cm-2. Column density at distant position from MD5 is larger than that in the (:entral region. We have deduced that this hot-core has a mass of 10sR1 which i:s about an order of magnitude larger those obtained by previous studies.previous studies.업순서들의 상관관계를 고려하여 보다 개선된 해를 구하기 위한 연구가 요구된다. 또한, 준비작업비용을 발생시키는 작업장의 작업순서결정에 대해서도 연구를 행하여, 보완작업비용과 준비비용을 고려한 GMMAL 작업순서문제를