• 천문학회보
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• 제44권1호
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• pp.80.2-80.2
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• 2019

We present newly discovered dwarf galaxy candidates in deep wide-field images of NGC 1291 obtained with KMTNet. We initially identify 20 dwarf galaxy candidates through visual inspection. 13 out of 20 appears to be high priority candidates, according to their central surface brightness (${\mu}_{0,R}{\sim}22.5$ to $26.5mag\;arcsec^{-2}$) and effective radii (350 pc to 1 kpc). Structural and photometric properties of dwarf candidates appear to be consistent with those of ordinary dwarf galaxies in nearby groups and clusters. Using imaging simulations, we demonstrate that our imaging data is complete up to $26mag\;arcsec^{-2}$ with > 70% of the completeness rate. In order to find an optimal way to automate detecting dwarf galaxies in our dataset, we test detection methods by varying parameters in SExtractor. We find that the detection efficiency from the automated method is relatively low and the contamination due to the artifacts is non-negligible. Therefore, it can be only applicable for pre-selection. We plan to conduct the same analysis for deep images of other nearby galaxies obtained through KMTNet Nearby Galaxy Survey (KNGS).

• 음성과학
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• 제2권
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• pp.109-124
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• 1997

This paper shows how a distinctive feature model can effectively be implemented into speech understanding within the framework of the Optimality Theory(OT); i.e., to show how distinctive features can optimally be extracted from given speech signals, and how segments can be chosen as the optimal ones among plausible candidates. This paper will also show how the sequence of segments can successfully be matched with optimal words in a lexicon.

• 한국공작기계학회논문집
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• 제13권4호
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• pp.79-86
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• 2004

Tooth errors inevitable in the manufacturing process have large effect on the strength/durability and vibration performances of gear drives. We show that the manufacturing errors affect the overall gear performances, especially vibration performance, and propose a robust optimal design method for gear dimension and its tooth flank form that guarantees reliable performances to the variation of manufacturing errors. This method begins with a search of optimal design candidates by using the previously developed gear optimal design method for the strength/durability and vibration performances. Then, the statistical analysis method is applied to find a robust design solution for the vibration performance which is generally very sensitive to the manufacturing variations.

• 한국컴퓨터정보학회논문지
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• 제20권12호
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• pp.75-82
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• 2015

Generally, the optimal solution of assignment problem can be obtained by Hungarian algorithm of two-sided optimization with time complexity $O(n^4)$. This paper suggests one-sided optimal assignment and swap optimization algorithm with time complexity $O(n^2)$ can be achieve the goal of two-sided optimization. This algorithm selects the minimum cost for each row, and reassigns over-assigned to under-assigned cell. Next, that verifies the existence of swap optimization candidates, and swap optimizes with ${\kappa}-opt({\kappa}=2,3)$. For 27 experimental data, the swap-optimization performs only 22% of data, and 78% of data can be get the two-sided optimal result through one-sided optimal result. Also, that can be improves on the solution of best known solution for partial problems.

• 정보과학회 논문지
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• 제43권11호
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• pp.1275-1280
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• 2016

유사 문자열 검색을 위해 기존의 기법들은 우선 후보 문자열 집합을 생성한 후에 후보 문자열을 검증하는 방법을 사용한다. 이때, 유사 문자열 검색의 성능을 결정짓는 가장 중요한 요소는 후보 생성 방법이다. 기존의 기법들은 질의 문자열로부터 고정길이 q-그램들을 선택하고, 선택된 q-그램에 해당하는 역리스트를 이용해 후보 문자열을 생성한다. 본 논문에서는 질의 문자열 내의 가변길이 그램들을 사용하여 후보 문자열을 생성할 수 있는 기법과 질의 문자열로부터 최적의 가변길이 그램들의 조합을 선택하는 동적 프로그래밍 알고리즘을 제안한다. 실험을 통해 제안하는 기법이 기존의 기법들 보다 유사 문자열 검색의 성능을 향상시킴을 보인다.

• 한국전자파학회논문지
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• 제25권10호
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• pp.1005-1019
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• 2014

본 논문은 미국 및 유럽을 중심으로 활발하게 진행되고 있는 주파수 공동사용에 대한 정책추진 현황 및 경제성 분석 결과, 이를 통한 주파수 공동사용의 후보 대역 선정 방안에 대해 제안하였다. 이를 위해 현재의 주파수 수요 급증에 대응하기 위해 시행되고 있는 주파수 할당 및 재배치 방법에 대한 추진현황과 문제점을 고찰하였으며, 이에 대한 해결방안으로 선진국을 중심으로 추진되고 있는 주파수 공동사용의 개념 및 국외 정책추진 현황, 사업자 관점에서의 주파수 공동사용에 대한 경제성 분석 결과를 소개하였다. 또한, 조사 및 분석결과를 통하여 주파수 공동사용의 후보 대역 선정을 위한 평가항목 및 선정기준에 대해 제안하였다.

• 천문학회보
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• 제43권2호
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• pp.53.2-53.2
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• 2018

We present newly discovered dwarf galaxy candidates in deep and wide-field images of NGC 1291 obtained with KMTNet. Through a visual inspection, we find ~ 13 candidates, for which central surface brightness ranges from ${\mu}_{0,R}{\sim}22.5$ to $26.5mag\;arcsec^{-1}$. Adopting the distance to NGC 1291, the candidate dwarfs are brighter than $M_R=-12.5mag$ and their effective radii range from 350 pc to 1.4 kpc. Structural and photometric properties of dwarf candidates near NGC 1291 appears to be consistent with those of ordinary dwarf galaxies in nearby galaxies. We conduct the imaging simulation in order to find an optimal way to detect dwarf galaxies in KMTNet images and to test the completeness of our detection algorithm. We plan to apply this method to deep KMTNet images of other nearby galaxies obtained through KMTNet Nearby Galaxy Survey (KNGS).

• International Journal of Oral Biology
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• 제37권2호
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• pp.43-50
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• 2012

The use of high throughput screening (HTS) in drug development is principally for the selection new drug candidates or screening of chemical toxicants. This system minimizes the experimental environment and allows for the screening of candidates at the same time. Umbilical cord-derived stem cells have some of the characteristics of fetal stem cell and have several advantages such as the ease with which they can be obtained and lack of ethical issues. To establish a HTS system, optimized conditions that mimic typical cell culture conditions in a minimal space such as 96 well plates are needed for stem cell growth. We have thus established a novel HTS system using human umbilical cord derived-mesenchymal stem cells (hUC-MSCs). To determine the optimal cell number, hUC-MSCs were serially diluted and seeded at 750, 500, 200 and 100 cells per well on 96 well plates. The maintenance efficiencies of these dilutions were compared for 3, 7, 9, and 14 days. The fetal bovine serum (FBS) concentration (20, 10, 5 and 1%) and the cell numbers (750, 500 and 200 cells/well) were compared for 3, 5 and 7 days. In addition, we evaluated the optimal conditions for cell cycle block. These four independent optimization experiments were conducted using an MTT assay. In the results, the optimal conditions for a HTS system using hUC-MSCs were determined to be 300 cell/well cultured for 8 days with 1 or 5% FBS. In addition, we demonstrated that the optimal conditions for a cell cycle block in this culture system are 48 hours in the absence of FBS. In addition, we selected four types of novel small molecule candidates using our HTS system which demonstrates the feasibility if using hUC-MSCs for this type of screen. Moreover, the four candidate compounds can be tested for stem cell research application.

• 한국항공운항학회지
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• 제20권4호
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• pp.31-38
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• 2012

In this paper, requirements of GNSS receiver station installation are derived for optimizing the performance of network based GNSS precise positioning by concern of international organization(IGS, NGS) recommendation. Also a analysis method of network based GNSS precise positioning is suggested in order to evaluate the availability depending on various network configurations. To evaluate network candidates, a performance evaluation method is proposed for positioning of users according to a geometric configuration and the baseline distance. After the proposed method is used to Ochang region that is a the test area 6 network candidates are derived and the performance of positioning was analyzed. Finally, Ansung, Gongju, Eumsung, Boeun network configuration was selected as the best positioning performance. An optimal Receiving station network was selected using the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.859-863
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• 1993

There are two methods to get 3-dimensional information by matching image pair feature-based matching and area-based matching. One of the problems in the area-based matching is how the optimal search region which gives accurate correlation between given point and its neighbors can be selected. In this paper, we proposed a new area-based matching algorithm which uses edge-features used in the conventional feature-based matching. It first selects matching candidates by feature-based and matches image pair with area-based method by taking these candidates as guidance to decision of search area. The results show that running time is reduced by optimizing search area(considering edge points and continuity of disparity), keeping on the precision as the conventional area-based matching method.