• Korean Journal of Agricultural Science
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• v.30 no.2
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• pp.139-147
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• 2003

The main purpose of this study is to obtain forest scenic beauty management informations toward forest working systems in pinus densiflora forest stands, etc. To get these information, visual preference and spatial image analysis methods are used. 25 different alternatives were simulated to visualize on basis of actual forest working methods with taken photos from May to July, 2003. The options were illustrated as photos produced by computer software. Respondents' ratings for 25 landscape scenes were obtained by interview survey method. Each alternatives were evaluated by forest major student group with total 103 respondents after reliability test. Visual preference evaluation was used 10 point rating scale. Spatial images of 12 alternatives were measured by 12 semantic differential scale. In general, the respondents preferred refreshing and ordering forest stand after forest working to natural forest stand before forest working. High visual preference for forest density produces 400-600 trees/ha in small diameter class forest stands. Regarding visual preference according to pavement type of trail, soil trail is ranked high. Visual preference for cutting area ranks mature forest stand and visual preference for trail slope cover type ranks shrub with grass as relatively high on the preference scale. Through the factor analysis, spatial images of 12 coniferous forest stands are classified as 'ordered opened' and 'beautiful healthy'. Results indicate how to conduct forest working systems for forest scenic beauty management.

• Geomechanics and Engineering
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• v.16 no.4
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• pp.449-461
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• 2018

The load sharing ratio (${\alpha}_{pr}$) of piles is one of the most common problems in the preliminary design of piled raft foundations. A series of 3D numerical analysis are conducted so that special attentions are given to load sharing characteristics under varying conditions, such as pile configuration, pile diameter, pile length, raft thickness, and settlement level. Based on the 3D FE analysis, influencing factors on load sharing behavior of piled raft are investigated. As a result, it is shown that the load sharing ratio of piled raft decreases with increasing settlement level. The load sharing ratio is not only highly dependent on the system geometries of the foundation but also on the settlement level. Based on the results of parametric studies, the load sharing ratio is proposed as a function of the various influencing factors. In addition, the parametric analyses suggest that the load sharing ratios to minimize the differential settlement of piled raft are ranging from 15 to 48% for friction pile and from 15 to 54% for end-bearing pile. The recommendations can provide a basis for an optimum design that would be applicable to piled rafts taking into account the load sharing characteristics.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.903-908
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• 2001

A web-based client/server program, MOVIDIK(Motor-Operated-Valve Integrated Database Information of KEPCO) has been developed to perform a design basis safety evaluation for a motor-operated-valve(MOV) in the nuclear power plant. The MOVIDIK consists of seven analysis modules and one administrative module. The analysis module calculates a differential pressure on the valve disk, thrust/torque acting at a valve stem, maximum allowable stress, thermal-overload-relay selection, voltage degradation, actuator output and margin. In addition, the administrative module manages user information, approval system and code information. MOVIDIK controls a huge amount of evaluation data and piles up the safety information of safety-related MOV. The MOVIDIK will improve the efficiency of safety evaluation work and standardize the analysis process for the MOV.

• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.2
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• pp.81-103
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• 1994

In recent years, the visual characteristics of natural open space and greenbelt surrounding the urban landscapes have been changed with sprawling of residential areas and highrised residential buildings. Since these natural areas being the background element of residential areas are topographically sloped mountains in many cities. It is easy to be seen in the distance and it is important to preserve these areas as a visual infrastructure of the urban landscape. The purposes of this study are to extract the factors of landscape impact evaluation for these areas and to clarify the physical landscape variables representing these factors, and to infer the visual-perceptional relationships between image and landscape variables. As results, conceptional three factors were extracted with semantic differential evaluation to classified 18 landscape slide, and three regression models were established with factor score of landscapes and physical variables measured in photographs. On the basis of these relationships, visual-perceptional characteristics were discussed by analyzing the data form eye-movement recording to each of landscapes. The factors of "spatial unfolding of backdropped hilly greenspace", "horizontal quence of residential buildings", and "landscape complexity" prove to be important. And it prove important variables of "skyline of mountainous ridge" and "visual edge of building structure" in regression models and eye fixation movements.

• Journal of The Korean Association of Information Education
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• v.10 no.2
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• pp.229-239
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• 2006

The present study analyzed the effects of Problem-Based Learning (PBL), founded on the constructivist theory, on the problem solving process and computer application ability as to students' level in elementary computer education. According to the PBL model, developed on the basis of previous research and the purpose of the study, the area of 'application of software' in third-grade computer curriculum was redesigned for the three-week period of the experiment. The results of the analyses showed that problem-based learning tended to exert differential effects with regard to students' level on the problem-solving process and computer application ability in computer education. The implications of the study and suggestions for the future study were discussed.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.2
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• pp.59-64
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• 2004

Most features of nature and phenomena we encounter in many branches of science are inherently very irregular and have fractal aspects. Thus the analysis of them with the traditional methods such as a differential operator may result in their ill-posed problems. To settle these problems, one may use several type of mean filters which smooth the input signal. However when a given function or data are complex in their nature, there may be loss of some original information during these process. In this paper, we utilized the tangent plane method instead of mean filters for the purpose of less loss of information and more smoothness. After then we attempt to take more accurate edges for the irregular image on the basis of the Otzu threshold. Finally we introduce the effective edge extracting method which use the fractal dimension representing the complexity of the given image.

• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.93-101
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• 1999

The purposed of this paper is to investigate the electrical and thermal stability of Polyvinylidene fluoride(PVDF) organic thin films prepared by the vapor deposition method. The differential scanning calorimetry curve of the PVDF organic thin films prepared by increasing substrate temperature showed that the melting curve increased from $128^{\circ}C$ to $142^{\circ}C$. This result implied that the PVDF organic thin film prepared by increasing substrate temperature increased intermolecular force in the crystalline region. The anomalous properties in dielectric constant and dielectric loss at low frequency and high temperature were described for PVDF organic thin film containing impurity carriers. It was confirmed that in view of electric conductive characteristics the ohm's law is satisfied in the range of lower electric field and ln J was proportional to the electric field ln E as like the conventional property of ionic conduction in the range of higher electric field. It was confirmed that major carrier of conductivity was ions. The electrical stability was improved according to an increase of the substrate temperature. On the basis of this experimental result, it could be observed that the optimum temperature of substrate for the electrical and thermal stability was at $105^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1954-1955
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• 2011

본 연구에서는 교육용으로 제작된 NXT 장비에 설치된 Light 센서, Ultrasonic센서, Sound센서를 이용하여 각 거리(10~60cm)에서 5cm 간격으로 각 센서 데이터를 취득하였다. 데이터 취득은 NI(National Instrument)에서 제공하는 LabVIEW Software를 사용하여 각 거리마다 100개의 셈플 데이터를 취득하였다. 취득한 데이터는 제안한 모델의 입력 데이터로 사용하여 실제거리와 모델 출력과의 정확도를 평가 하였다. 본 연구에서 제안한 모델은 지능형 모델 중 퍼지추론 기반의 최적 다항식 RBF 뉴럴네트워크(Radial Basis Function Neural Network; RBFNN)를 설계한다. 제안된 RBFNN은 기존 RBF 뉴럴네트워크를 기반으로 한 구조로, 퍼지추론 메커니즘의 기능적 모듈 동작 특성을 갖도록 정규화 부분을 추가하고, 은닉층과 출력층 사이의 연결가중치를 기존 상수항에서 선형식(first order)으로 확장한 형태이다. 또한 최적의 알고리즘인 PSO(Paticle Swarm Optimization)와 DE(Differential Evolution)을 이용하여 제안된 모델의 파라미터들을 동정하여 성능을 비교, 분석 하였다.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.788-797
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• 2011

This paper analyzes the accuracy on the approach and landing of aircraft to an airport through comparison with airbase Precision Approach Radar and aircraft track data of DGPS equipped in aircraft. The proposed analysis result could be a basis for verifying the possibility that DGPS can be utilized in Airbase precision approach and landing. Position identification capability of widely used commercial DGPS is fairly accurate on latitude and longitude, while there is a slight error for being used in an airbase accurate approach and landing of Category I precision when it comes to altitude. Thus, we tested accuracy by analyzing actual flight track data of high performance aircraft to verify the accuracy of the airbase approach and landing using DGPS. Through the research, we developed instrumentation to compare PAR track data with DGPS track data, which can be used in reducing the number of PAR verification Flight utilizing it as a system measuring PAR accuracy at PAR installation phase.

• Structural Engineering and Mechanics
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• v.45 no.1
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• pp.95-110
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• 2013

In the recent decade, practical of wavelet technique is being utilized in various domain of science. Particularly, engineers are interested to the wavelet solution method in the time series analysis. Fundamentally, seismic responses of structures against time history loading such as an earthquake, illustrates optimum capability of systems. In this paper, a procedure using particularly discrete Haar wavelet basis functions is introduced, to solve dynamic equation of motion. In the proposed approach, a straightforward formulation in a fluent manner is derived from the approximation of the displacements. For this purpose, Haar operational matrix is derived and applied in the dynamic analysis. It's free-scaled matrix converts differential equation of motion to the algebraic equations. It is shown that accuracy of dynamic responses relies on, access of load in the first step, before piecewise analysis added to the technique of equation solver in the last step for large scale of wavelet. To demonstrate the effectiveness of this scheme, improved formulations are extended to the linear and nonlinear structural dynamic analysis. The validity and effectiveness of the developed method is verified with three examples. The results were compared with those from the numerical methods such as Duhamel integration, Runge-Kutta and Wilson-${\theta}$ method.