• 천문학회보
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• 제46권2호
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• pp.42.1-42.1
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• 2021

Galaxy/Halo finding based on the friends-of-friend (FoF) algorithm has been widely adopted for its simplicity and expandability to the phase-space. However, cosmological simulations have been progressively bigger in size and more accurate in resolutions, resulting in that galaxy/halo finding gets computationally expensive more and more. In fact, we confirm this issue through our exercise of applying the 6-dimensional (6D) FoF galaxy finder code, VELOCIraptor (Elahi et al.2019) on the NewHorizon simulation (Dubois et al. 2021), in which typical galaxies with about 1e11 M_sun (10⁷ particles) are identified with very low speed (longer than a day). We have applied several improvements to the original VELOCIraptor code that solve the low-performance problem of galaxy finding on a simulation with high resolutions. Our modifications find the exact same FoF group and can be readily applied to any tree-based FoF code, achieving a 2700 (12) times speedup in the 3D (6D) FoF search compared to the original execution. We applied the updated version of VELOCIraptor on the entire NewHorizon simulation (834 snapshots) and identified its galaxies and halos. We present several quick comparisons of galaxy properties with those with GALAXYMaker data.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.92-99
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• 2024

To minimize the cumulative radiation dose, various path-finding approaches for single agent have been proposed. However, for emergence situations such as nuclear power plant accident, these methods cannot be effectively utilized for evacuating a large number of workers because no multi-agent method is valid to conduct the mission. In this study, a novel algorithm for solving the multi-agent path-finding problem is proposed using the conflict-based search approach and the objective function redefined in terms of the cumulative radiation dose. The proposed method can find multi paths that all agents arrive at the destinations with reducing the overall radiation dose. To verify the proposed method, three problems were defined. In the single-agent problem, the objective function proposed in this study reduces the cumulative dose by 82% compared with that of the shortest distance algorithm in experiment environment of this study. It was also verified in the two multi-agent problems that multi paths with minimized the overall radiation dose, in which all agents can reach the destination without collision, can be found. The method proposed in this study will contribute to establishing evacuation plans for improving the safety of workers in radiation-related facilities.

• 한국조경학회지
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• 제35권3호
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• pp.62-70
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• 2007

The purpose of this research is to suggest an improved method of how to apply and operate an average floor height system to rebuilt or redeveloped apartment buildings in general residential areas of Seoul. This research suggested two research findings by a computer simulation study for analyzing the difference between the average floor height of apartment buildings in experimental sites and the average of floors of buildings near experimental sites. The first finding is that an average floor height system should be applied to apartment buildings with a limitation of maximum height at sites larger than $12,000m^2$ in order to control the difference of the maximum height of buildings between apartment sites and their surroundings. The second finding is that the average floor height system should be operated by an appropriate average floor height ratio at sites greater than $50,000m^2$ in order to harmonize rebuilt or redeveloped apartment buildings with their surroundings.

• 아태비즈니스연구
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• 제7권2호
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• pp.1-19
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• 2016

This study has analyzed the interrelation between transformational leadership (TL) and organizational commitment (OC) so as to verify the mediating effect of their trust on OC, finding that charisma and intellectual stimulus have a significant effect on affective and continuous commitment. This finding is different from any existing arguments where the charisma of TL and the individual consideration are said to have a significant and positive effect on affective and continuous commitment. Furthermore, the mediating effect, which was expected to be highly relevant on the grounds of the findings of previous researches that any high trust of a leader would lead to a high level of OC of members, has been revealed as a complete mediation in the relationship of emotional trust between individual consideration and OC, which shows that the correlation between TL and OC may vary depending on the characteristics of an organization and its members both of which are sample objects. This study, unlike most previous researches with their research samples in industrial fields, has estimated the growing interrelation of NGOs. Therefore, while this study itself may have its research-limit of specificity, it is expected to make a useful contribution to any future researches of the same category.

• ETRI Journal
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• 제35권2호
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• pp.281-291
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• 2013

A video signature is a set of feature vectors that compactly represents and uniquely characterizes one video clip from another for fast matching. To find a short duplicated region, the video signature must be robust against common video modifications and have a high discriminability. The matching method must be fast and be successful at finding locations. In this paper, a frame-based video signature that uses the spatial information and a two-stage matching method is presented. The proposed method is pair-wise independent and is robust against common video modifications. The proposed two-stage matching method is fast and works very well in finding locations. In addition, the proposed matching structure and strategy can distinguish a case in which a part of the query video matches a part of the target video. The proposed method is verified using video modified by the VCE7 experimental conditions found in MPEG-7. The proposed video signature method achieves a robustness of 88.7% under an independence condition of 5 parts per million with over 1,000 clips being matched per second.

• 산경연구논집
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• 제14권5호
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• pp.11-18
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• 2023

Purpose: The current research based on the comprehensive literature evaluation aims to gain insight into the factors contributing to an Oriental art gallery's success and the strategies used to advertise and sell these works effectively. Understanding and experience in Oriental art are essential for finding solutions to these issues. Research design, data and methodology: The current research conducted the following stages to conduct a thorough literature analysis on the issues that plague Oriental art gallery practitioners and the methods used to increase sales of this kind of art: Finding Valuable Resources and Subjects, Screening and Selection of Articles, Data Extraction and Analysis, Synthesis of Findings. Results: After reviewing the many aspects that affect the success of a gallery specializing in Oriental art, there were four key approaches that have emerged for boosting sales of this kind of artwork. Based on the findings, these approaches are grounded in four areas: consumer preferences; marketing methods; pricing strategies; and art investments. Conclusions: All in all, the current study finally indicates that practitioners should consider cultural background, age, gender, income, and level of education when developing marketing strategies and selecting artwork to exhibit. Target marketing is an effective method for attracting and retaining customers.

• 한국경영과학회지
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• 제19권1호
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• pp.201-206
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• 1994

The linear search problem is concerned with finding a hiden target on the real line R. The position of the target governed by some probability distribution. It is desired to find the target in the least expected search time. This problem has been formulated as an optimization problem by a number of authors without making use of Markov Decision Process (MDP) theory. It is the aim of the paper to give a (MDP) formulation to the search problem which we feel is both natural and easy to follow.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 C
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• pp.1036-1038
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• 1998

The while, PD source detection in the oil TR was the level of the planar source detection. and it is to respected scientific research. The planar source detection technique had limits which have difficulties finding out the point of deterioration generation. In this study, our purpose is a development of PD source detection technique with Three-Dimensional using a principle and a technique of the planar source location.

• 한국전자파학회논문지
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• 제23권10호
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• pp.1166-1172
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• 2012

본 논문에서는 상용 EM 시뮬레이션을 이용하여 안테나의 위상 응답 특성인 어레이 매니폴드를 계산하는 방법을 제안하고 실제 측정값과 비교하여 그 유효성을 검증하였다. EM 시뮬레이션을 적용하여 확보된 어레이 매니폴드는 point source에 의한 이상적인 이론값과 비교 시 안테나 자체와 안테나가 장착되는 플랫폼에 의한 영향을 정확히 계산할 수 있으며, 보정시 전계강도가 큰 주변의 FM/TV 등의 방송 신호나 다중 반사에 의한 왜곡 등을 배제시킬 수 있는 장점이 있다. 또한, 방향 탐지 시스템의 성능을 예측하기 위해서 세밀한 간격으로 수신 신호를 시뮬레이션하고 그 중 일부를 어레이 매니폴드로 적용한 후 파라볼릭 추정 방법을 이용하여 대상 신호원의 방향을 예측하는 방법을 제안하였다. 제안된 방법은 수신 신호의 SNR이 비교적 낮은 조건에서도 정확하게 측정 결과를 예측할 수 있어 방향 탐지 분야에 다양하게 활용될 수 있을 것으로 기대된다.

• 한국과학교육학회지
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• 제32권4호
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• pp.570-585
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• 2012

우리나라 과학과 교육과정에서 문제해결력이 중요함을 강조하고 있다. 과학 교육에서 문제해결력에 대한 많은 연구가 이루어져왔다. 이러한 연구들은 잘 정의된 문제, 구조화된 문제를 대상으로 연구하였기 때문에, 빈약하게 정의된 문제, 비구조화된 문제의 해결과정에 대한 연구가 더 이루어져야 한다는 지적을 받았다. 비구조화된 문제는 전체적인 목표는 존재하지만, 제공되는 정보가 적거나 거의 없는 상황이므로, 비구조화된 문제를 해결하기 위해서는 반드시 문제발견이 선행되어야 한다. 그리고 비구조화된 상황에서 문제발견은 창의성과 관련되기 때문에, 창의적 문제해결력을 향상시키기 위해 비구조화된 문제발견을 학습할 필요가 있다. 과학 영역에서 비구조화된 문제발견에 대해, 교실현장에 구체적으로 도움이 될 수 있는 가이드를 만들기 위해서, 비구조화된 상황에서 과학적 문제발견 과정에 대한 경험적 연구가 필요하다. 이 연구에서는 이공계 대학생 32명을 대상으로, 면담을 통해서 실제로 비구조화된 상황에서 과학적 문제발견 과정과, 그 과정에 영향을 준 요소가 무엇인지 알아보았다. 비구조화된 문제 상황에서 학생들의 문제발견 과정은, 문제와 관련된 단서나 잠정적 해결책을 염두에 두고, 정보를 검색한 후 몇 가지 선별 기준에 따라서 검색된 정보를 선별하여 문제를 발견하는 것으로 이루어졌다. 학생들의 문제발견에 영향을 미친 요인은 먼저, 문제에 관한 단서를 떠올리는데 전공 수업과 영화, 소설 등 학생의 경험이 영향을 미쳤다. 문제해결자의 문제 관련 배경 지식이 잠정적 해결책에 영향을 미쳤고, 검색한 정보를 선별하는 선별 기준으로 정보의 신뢰도, 정보의 출처, 내용 적합성, 이해 가능성, 주제와 관련성, 언급된 회수가 사용되었다. 그런데 연구에 참여한 대학생들이 제시한 정보선별 기준이 타당한지, 중등학교 현장에서 교사가 안내할 가치가 있는지, 학습에 도움이 되는지 여부는 알 수 없으므로 이에 대해서는 추가 연구가 필요하다. 연구에 참여한 대학생들은 개연성 있는 모델을 만들기 위해, 문제를 명료화할 때 가정을 사용하였다. 가능한 모든 변수를 포함한 문제를 해결하는 것은 현실적으로 불가능하기 때문에, 가정을 사용해서 불필요한 요소를 배제하는 접근법은 적절한 전략이라고 생각된다. 따라서, 중등학교 현장에서 교사는 학생들에게 비구조화된 상황에서 문제를 발견할 때 적절한 가정을 사용함으로써 문제를 명료화할 수 있다는 점을 알려 줄 수 있을 것이다.