• 한국자기공명학회논문지
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• 제9권1호
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• pp.67-73
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• 2005

$^{27}AI$ triple quantum magic angle spinning (3QMAS) NMR spectra of several mordenite (MOR) sample were simulated with the point charge model method and compared with experimental 3QMAS spectra. Signal positions from different tetrahedral (T) sites in 3QMAS spectra are mainly governed by local structures of T sites such as T-O-T angles and T-O bond lengths. When preparation methods, cations in addition to Si/Al rations vary, the local structures of T sites in MOR change enough to alter signal patterns in 3QMAS of MOR. This inhibits to study the of Al distribution variation over 4 different T sites in mordenite during process such as dealumination by 3QMAS spectra.

• Imaging Science in Dentistry
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• 제31권1호
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• pp.43-49
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• 2001

Purpose: To investigate the shape and size of normal sella turcica on cephalometric radiograms. Materials and Methods: Cephalometric radiograms of 200 orthodontic patients of age ranging 6-42 years were examined. All subjects were divided into 5 groups by age, the dimensional change of sella turcica was examined according to age, and the configurations of sella turcica floor, tuberculum sella, and anterior and posterior clinoid process were also observed. Results: The contours of sella turcica floor were flat type in 54% and concave type in 46%. The contours of tuberculum sella were right angle type in 55% and obtuse angle type in 44%; Acute angle type and plane type were very rare comprising 0.5%, 0.5% each. The configurations of anterior clinoid process were point type in 80% and round type in 20% of cases, and those of posterior clinoid processes were point type in 60% and round type in 40% of cases. The dimensional change of sella turcica according to age range had significantly positive linear trend to sella turcica length, height, and width until 25 years. After 26 years, no significant increase was found in sella turcica dimension. Especially, the sella turcica length had more proportional increase than that of sella turcica height and width. Conclusion : The results of this study revealed that the configuration of normal sella turcica was variable and the dimensional change of normal sella turcica had a linear tendency with age until 26 years.

• 농촌계획
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• 제25권4호
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• pp.47-56
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• 2019

More than half of the nonpoint sources of polluting water occur in cultivating farmlands in rural areas. Agricultural nonpoint sources are discharged from large areas of farmlands, making it difficult to collect or treat pollutants. Farmland source management is known to be the most effective, and preventive management by improving farming methods is the key to reduce nonpoint pollution. At present, more than 30% of the pollutants flowing into the rivers and lakes are nonpoint pollutants caused by agricultural activities. As a countermeasure, it is more preferable to develop and apply optimal farming management techniques for agricultural nonpoint pollution management basically than to apply existing water quality management techniques. Because of the characteristics of nonpoint source pollution, it is necessary to manage farmlands in rural areas, so the willingness and competence of the residents is most important. The purpose of this study is to analyze and understand the process of changing the cognition of residents through capacity education and survey for nonpoint pollution management in rural areas. This study conducted intensive resident competency education and examined the process of changing resident awareness through three surveys. As a result of this study, it was found that continuous education and activities for rural non-point pollution management are necessary for raising awareness of residents and managing non-point pollution effectively, showing possibility of change residents' perception.

• Spatial Information Research
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• 제6권1호
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• pp.77-90
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• 1998

자연적이거나 인위적인 여러 요인의 복합적인 상호작용에 의해 지표는 계속 변화해간다. 자연재해는 생태계의 다양한 군집이 서로 상호작용을 하는데 결정적 영향을 미치는 요소로 이런 변화의 직접적인 원인이 되는 특정 사건의 발생과정이나 공간적 분포에 대한 연구는 환경과 자원관리 측면에서 중요하다. 본 논문에서는 지표변화에 영향을 미치는 자연화재의 경우를 중심으로 공간적 분포를 모형화하는 방법론을 설명하였다. 자연화재는 주로 번개에 의해 발생되어 몇 주에 결쳐 수만 킬로미터의 지역을 태우면서 새롭고 다양한 서식지를 만들어 가는 주된 자연재해중의 하나로 생태계관리차원에서 연구되고 있다. 오스트리아 빅토리아사막을 예로 이곳에서의 자연화재 발생지역을 20년동안의 원격탐사자료(MSS data)로부터 추출하여 이를 바탕으로 자연화재발생에 대한 공간적 모형을 개발하였고 모형에 입각한 시뮬레이션 방법을 논의하였다. 화재발생과정은 불규칙적으로 분포된 공간상의 point pattern에 의해 특징지어질 수 있는데 이의 모형화를 위해서 Nonhomogeneous Planar Poissin Process가 이용되었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.1153-1155
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• 2017

발사체는 여러 부품이 모여 하나의 시스템으로 만들어진다. 여러 조직에서 개발되는 여러 부품을 하나의 시스템으로 만들기 위해서는 특정 시점에 모든 설계의 확정이 필요하다. 설계 확정 이후 변경은 통제된 절차 속에서 변경의 영향을 분석하고, 변경을 할지 말지 결정을 하고, 변경이 의도된 대로 잘 실시되었는지 확인하는 과정이 필요하다. 한국형발사체 개발과정에도 위와 같은 방식으로 구현된 형상 관리 절차를 적용하고 있다. CAD툴과 PLM을 연계하여 3D모델과 2D도면, 형상식별문서에 대해서 형상관리를 시행하고 있다.

• 마케팅과학연구
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• 제7권
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• pp.71-103
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• 2001

Marketing practice varies among firms. However, the prescriptive literature emphasises a universal view of practice, a 'one size fits all' view. This paper addresses the issue of explaining diversity in marketing practice in competitive space and in time. Diversity in competitive space reflects the existence of different routes to high performance. Diversity in time reflects some combination of change in the individual firm and change in a population of firms. In the former case, diversity is shaped by organisational change; in the latter by the disbandment and founding of firms in the population. In so far as diversity is the norm, the manner in which practice will be shaped by evolutionary processes is considered. Fnally, the role of the academy as one of the forces driving the evolutionary process is discussed. Miles and Snow's (1978, 1986) work is taken as a main point of departure in the search for explanation and ecological and evolutionary concepts are drawn on for support and to suggest an explanation for the nature of diversity over time.

• 물과 미래
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• 제25권2호
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• pp.67-78
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• 1992

Several field surveys were conducted to investigate changes of water quality with time in a tidal river. Results indicated that nitrification process were dependent on the change of salinity and suspended solids concenttration. Therefore laboratory batch experiments were conducted, using suspended solids and sediment taken from a tidal river, to study the effect of salinity on nitrification and to estimate kinetic parameters of it in the tidal river. suspended solids and sediment were sampled at a point in the middle stream. Sediments were collect from the aerobic layer of mud. The change of nitrogen concentration with time was clearly explained with Monod groth model and kinetic parameters were obtained by curve fitting method. Changes in NH4-N, NO2-N, and NO3-N concentrations in the river ROKKAU with time were simulated well using Lagrangian reference frame and parameter values obtained in the laboratory tests. T도 mechanism of nitrification by suspended solids and sediment in a tidal river is shown to depend on tidal effects.

• 한국해안·해양공학회논문집
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• 제22권3호
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• pp.163-170
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• 2010

평면파 근사식에 기초한 지형에 의한 파랑변형 모형인 산란체법과 변환행렬법을 비교하여 특성을 분석하였다. 산란체법의 결과가 기존 엄밀해에 보다 근접하고 내재한 물리현상을 보다 명확히 설명하는 것으로 평가된다. 이들은 해석해로 계산이 빠르고 용이하며 지형이 비교적 단순한 경우에는 상당한 정밀도를 보인다.

• 품질경영학회지
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• 제35권2호
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• pp.37-44
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• 2007

Today, the statistical process control (SPC) in manufacture environment is an important role at the process by the productivity improvement of the manufacturing systems. The control chart in this statistical method is widely used as an important statistical tool to find the assignable cause that provoke the change of the process parameters such as the mean of interest or standard deviation. But the traditional SPC don't grasp the change of process according to the points fallen the near control limits because of monitoring the variance of process such as the fixed sampling interval and the sample size and handle the cost of the aspect of these sample point. The control chart can be divided into the statistical and economic design. Generally, the economic design considers the cost that maintains the quality level of process. But it is necessary to consider the cost of the process improvement by the learning effects. This study does the economic design in the VSI $\bar X$ control chart and added the concept of loss function of Taguchi in the cost model. Also, we preyed that the VSI $\bar X$ control chart is better than the FSI $\bar X$ in terms of the economic aspects and proposed the standard of the process improvement using the VSI $\bar X$ control chart.

• 응용통계연구
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• 제21권5호
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• pp.813-823
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• 2008

비동질적 포아송과정(NHPP) 모형은 신뢰성 공학에서 소프트웨어 내에 남아있는 결함발견현상을 설명하는데 자주 사용된다. 이때 결함발견율은 연속적이며 단조함수를 가정하였으나 현실적으로 소프트웨어 시험환경, 전략 및 자원할당 등으로 인해 결함발견율이 변하는 경우가 있다. 본 논문은 결함발견율이 변화하는 변화점 문제를 고려한 소프트웨어 신뢰도 성장모형(SRGM)을 고려하여 모수를 추정하는데 목적이 있다. 이를 위해 자료를 모의 생성한 후 평균값 함수의 각 모수를 최우추정법과 최소제곱법을 이용하여 추정하며, 결함발견구간이 일정하게 증가하는 경우와 일정하게 증가하지 않는 경우를 각각 고려한다. 이때 각 모수의 적합도 비교 평가를 통하여 변화점을 고려한 SRGM에서의 최적 추정법을 수치적 방법으로 판단한다.