• 대한소아치과학회지
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• 제34권1호
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• pp.169-178
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• 2007

혼합치열기에 있어서 가장 흔히 나타나는 부정교합의 한 유형으로 총생 문제를 들 수 있다. 총생은 그 심한 정도에 따라서 정상적인 치열 발육 과정에서 일시적으로 나타나는 경우도 있으며 치열공간과 치아 크기간의 부조화에 의해서 비정상적으로 나타나는 경우도 있다. 따라서 총생에 대한 관리를 적절하게 하기 위해서는 정상적인 치열 발육 과정에 대한 이해가 선행되어야 한다. 본 종설에서는 정상적인 치열 발육 과정 및 총생의 심한 정도나 위치에 따른 일반적인 접근 방법에 대하여 알아보고자 하였다. 영구치가 맹출되는 시기는 개인 마다 다를 뿐만 아니라 맹출 순서에 있어서도 개인적인 편차가 심하므로 총생에 대한 관리는 일반적인 지식뿐만 아니라 개개인의 특성에 적합한 방법이 고려되어야 한다.

• 논리연구
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• 제8권1호
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• pp.47-67
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• 2005

베이즈망은 탐구 공간을 구성하는 변수들 사이에 성립하는 확률적 관계를 이용하여 그 변수들 사이에 성립된다고 가정되는 인과 관계를 추론하는데 이용된다. 베이즈망에 관한 철학적 논쟁의 대상은 특정한 변수들의 확률적 독립성을 가정하는 인과적 마코프 조건이다. 베이즈망 이론에 대한 강력한 비판자인 카트라이트는 인과적 마코프 조건이 비결정적 세계에서는 성립될 수 없기 때문에 인과적 추리에 대한 타당한 원리가 될 수 없다고 주장한다. 이글의 목적은 인과적 마코프 조건이 인과적 추리에 대한 타당한 원리가 될 수 없다는 카트라이트의 비판이 타당한가를 검토하는 것이다. 나는 인과적 사건들의 연쇄를 허용하는 연속모델은 카트라이트의 비판을 벗어날 수 있다고 주장한다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2004년도 추계학술대회 및 정기총회
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• pp.13-16
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• 2004

This paper deals with a one-searcher multi-target search problem where targets with different detection priorities move in Markov processes in each discrete time over a given space search area, and the total number of search time intervals is fixed. A limited search resource is available in each search time interval and an exponential detection function is assumed. The searcher can obtain a target detection award, if detected, which represents the detection priority of target and is non-increasing with time. The objective is to establish the optimal search plan which allocates the search resource effort over the search areas in each time interval in order to maximize the total detection award. In the analysis, the given problem is decomposed into intervalwise individual search problems each being treated as a single stationary target problem for each time interval. An associated iterative procedure is derived to solve a sequence of stationary target problems. The computational results show that the proposed algorithm guarantees optimality.

• Journal of Pharmaceutical Investigation
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• 제26권1호
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• pp.55-59
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• 1996

The crystal structure of diflunisal, 2',4'-difluoro-4-hydroxy-3-biphenyl-carboxylic acid, was determined by single crystal X-ray diffraction technique. The compound was recrystallized from a mixture of acetone and water in monoclinic, space group C2/c, with $a\;=\;34.666(6),\;b\;=\;3.743(1),\;c\;=\;20.737(4)\;{\AA},\;{\beta}=\;110.57(2)^{\circ}$, and Z = 8. The calculated density is $1.324\;g/cm^3$. The structure was solved by the direct method and refined by full matrix least-squares procedure to the final R value of 0.045 for 1299 observed reflections. It was found that the molecules in the crystal are partially disordered, that is, the two equivalent conformers $(180^{\circ}$ rotated ones through C(1)-C(7)) are packed alternatively without regular symmetry or sequence. The two phenyl rings of the biphenyl group is tilted to each other by the dihedral angle of $43.3^{\circ}$. The carboxyl group at the salicylic moiety is just coplanar to the phenyl ring, and the planarity of this salicylic moiety is stabilized by an intramolecular hydrogen bond of O(3)-H(O3) O(2). The molecules are dimerized through the intermolecular hydrogen bonds at the carboxyl group in the crystal.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.387-388
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• 2006

In this paper, we propose an efficient algorithm based on PCA and LDA combining K-means clustering method, which has better accuracy of face recognition than Eigenface and Fisherface. In this algorithm, PCA is firstly used to reduce the dimensionality of original face image. Secondly, a truncated face image data are sub-clustered by K-means clustering method based on Euclidean distances, and all small subclusters are labeled in sequence. Then LDA method project data into low dimension feature space and group data easier to classify. Finally we use nearest neighborhood method to determine the label of test data. To show the recognition accuracy of the proposed algorithm, we performed several simulations using the Yale and ORL (Olivetti Research Laboratory) database. Simulation results show that proposed method achieves better performance in recognition accuracy.

• 한국전자통신학회논문지
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• 제5권5호
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• pp.459-464
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• 2010

컴퓨터 프로그램은 기계, 우주, 항공, 의학을 비롯한 사회 전 분야에서 필요로 한다. 하지만 프로그래밍 교육과정은 수많은 교재와 동영상 강의에도 불구하고 어려워하고 있다. 프로그래밍 언어는 매우 다양하지만 대부분의 언어들은 동일한 구조를 사용하며, 표현 방식에 차이가 있을 뿐이다. 그래서 하나의 프로그래밍 언어를 습득하면 또 다른 언어를 배우는데 많은 시간과 노력을 기울이지 않아도 된다. 대부분의 프로그래밍 언어들은 일반적으로 순서, 선택, 반복 구조를 사용한다. 프로그래밍을 배우는 사람에게 중요한 것은 프로그램의 문법이 아니라 프로그램의 구조나 알고리즘이다. 본 논문에서는 순서도를 활용해 구조화된 프로그래밍을 학습할 수 있는 언어 학습 시스템을 설계하고 구현하였다.

• 천문학회보
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• 제41권1호
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• pp.65.2-65.2
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• 2016

We present a new database of our two-dimensional bulge-disk decompositions for 14,482 galaxies drawn from SDSS DR12 in order to examine the properties of bulges residing in the local universe (0.005 < z < 0.05). We performed decompositions in g and r bands by utilizing the GALFIT software. The bulge colors and bulge-to-total ratios are found to be sensitive to the details in the decomposition technique. The g-r colors of bulges derived are almost constantly red regardless of bulge size except for the bulges in the low bulge-to-total ratio galaxies (approximately $B/T_r{\leq}0.3$). Bulges exhibit similar scaling relations to those followed by elliptical galaxies, but the bulges in galaxies with lower bulge-to-total ratios clearly show a gradually larger departure in slope from the elliptical galaxy sequence. The scatters around the scaling relations are also larger for the bulges in galaxies with lower bulge-to-total ratios. Both the departure in slopes and larger scatters are likely originated from the presence of young stars. While bulges seem largely similar in optical properties to elliptical galaxies, they do show clear and systematic departures as a function of bulge-to-total ratio. The stellar properties and perhaps associated formation processes of bulges seem much more diverse than those of elliptical galaxies.

• 천문학회보
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• 제39권1호
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• pp.83.1-83.1
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• 2014

Open clusters consisting of a co-spatial and coeval population with a similar chemical composition are a superb astrophysical test bed in both stellar and galactic astronomy. We introduce not only several scientific issues relating to these objects but also comprehensive studies of the two young open clusters Westerlund 1 and IC 1848 formed in extremely different star-forming conditions. Westerlund 1 is known as the most massive starburst cluster in the Galaxy. Located in the Scutum-Centaurus spiral arm, the cluster is relatively close to the Galactic Center. The apparent surface density is very high. On the other hand, IC 1848 is a core cluster within the large-scale star-forming region W5 lying in the Perseus arm. Unlike Westerlund 1, IC 1848 with a putatively low metallicity exhibits a low surface density. We present the fundamental parameters of those young clusters, such as reddening, distance, and age, obtained from the broadband photometric analysis. The stellar initial mass function (IMF) of the clusters is used to investigate the effects of the different star-forming conditions on the star formation activity. With the results of previous studies for several young open clusters, our preliminary results support a possibility that star formation activity may be affected by the environmental factors or the initial condition of natal clouds. In addition, we shortly discuss the age scale and spread of pre-main sequence stars to understand the formation processes of star clusters.

• 한국건축시공학회지
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• 제6권2호
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• pp.81-89
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• 2006

A down construction method is frequently used in these days to reduce popular discontent and to assure sufficient working space at early stage in downtown area. There are two main problems in the existing down construction method. One is a confliction between frame works and excavation works, and the other is a cold joint in retaining wall which is unavoidable due to a sequence of concrete placement and induces a water leakage. Therefore, a new method is needed to overcome these problems. The CWS (buried wale Continuous Wall System) method was developed by authors. By replacing RC perimeter beam with embedded steel wale, the steel frame works of substructure can be simplified and the water leakage can be prevented using continuous retaining wall. Consequently, the improved qualify and reduction of construction period can be obtained from CWS method.

• BMB Reports
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• 제51권1호
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• pp.1-2
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• 2018

Positive selection on a new beneficial mutation generates a characteristic pattern of DNA sequence polymorphism when it reaches an intermediate allele frequency. On genome sequences of African Drosophila melanogaster, we detected such signatures of selection at 37 candidate loci and identified "sweeping haplotypes (SHs)" that are increasing or have increased rapidly in frequency due to hitchhiking. Based on geographic distribution of SH frequencies, we could infer whether selective sweeps occurred starting from de novo beneficial mutants under simple constant selective pressure. Single SHs were identified at more than half of loci. However, at many other loci, we observed multiple independent SHs, implying soft selective sweeps due to a high beneficial mutation rate or parallel evolution across space. Interestingly, SH frequencies were intermediate across multiple populations at about a quarter of the loci despite relatively low migration rates inferred between African populations. This invokes a certain form of frequency-dependent selection such as heterozygote advantage. At one locus, we observed a complex pattern of multiple independent that was compatible with recurrent frequency-dependent positive selection on new variants. In conclusion, genomic patterns of positive selection are very diverse, with equal contributions of hard and soft sweeps and a surprisingly large proportion of frequency-dependent selection in D. melanogaster populations.