• Clean Technology
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• v.14 no.1
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• pp.47-52
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• 2008

Among various mass transfer models to express adsorption rates for any adsorption processes, the linear driving force (LDF) model is used most. The present investigation aims at finding whether this model may be applied to real adsorption process for separation and removal of benzene. Comparison of numerical simulation results calculated by the LDF model with experimental data allowed us to find the mass transfer coefficients that are most appropriate for a specific adsorption process. Various breakthrough curves were obtained from experiments performed at many different temperatures and pressures, which in turn produced suitable mass transfer coefficients. These dependencies of mass transfer coefficient on temperature and pressure were represented by an Arrhenius type- and a power law type empirical equation, respectively.

• Elastomers and Composites
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• v.45 no.4
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• pp.250-255
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• 2010

From the three element non-Newtonian model of one non-Newtonian viscoelastic Maxwell elements and a elastic spring, the stress relaxation equation was derived. The various model parameters of this equation were evaluated by appling the experimental results of stress relaxation to the stress relaxation equation. The theoretical curves calculated from this model parameters agreed with the experimental stress relaxation curves. From the parameters of nonlinear viscoelastic model, the hole volume, fine structure, viscoelastic properties and mechanical properties of polymer fibers were studied. The experiments of stress relaxation were carried out using the tensile tester with the solvent chamber. The stress relaxation curves of the two types polyacrylonitrile-polyvinylchloride copolymer and another two types PVC monofilament fibers were obtained in air and water of various temperatures.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.39-42
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• 2022

쌀을 주식으로 하는 우리나라에서, 쌀의 가격에 영향을 미치는 변수를 찾는 것은 유의미한 연구이다. 본 논문에서는 쌀 가격을 예측하는 모델에 포함되는 여러 변수 가운데 상대적인 중요도가 낮은 변수를 제거하고 유의미한 변수만을 남기고자 한다. 이를 위해 기상, 수확량, 소비자물가의 10년 치 정보를 수집하고 정제한 결과 총 2460일, 7개 지역에서 추출된 17,219개의 데이터를 이용하였다. 모델 평가 결과, 모든 변수를 포함한 모델의 RMSE는 166.0759, 단계적으로 계수가 작은 9개의 변수를 제거한 최종적인 모델의 RMSE는 168.5576으로 유의미한 차이를 보이지 않았다. 최종적으로 남은 변수는 총 10개로 평균 기온, 평균 풍속, 합계 일사, 평균 지면 온도, 0.5M 평균 습도, 4.0M 평균 습도, 10CM 일 토양 수분, 30CM 일 토양 수분, 50CM 일 토양 수분, 전년도 생산량이 포함된다.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.452-454
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• 2008

본 논문에서는 실험적으로 구한 엔진 토크 참조 표를 이용하여 엔진의 비선형 모델을 구하고 이를 각각의 운전 점에 대해 선형화한 엔진 모델을 제시하였다. 이러한 선형화된 엔진 모델을 이용하여, 전기식 조속기를 사용한 디젤 엔진의 속도 제어에 있어 발생하는 안정성 문제를 해석하였다. 제시한 디젤 엔진 모델을 이용하여 속도제어기의 비례, 적분 미분 이득을 설정하고 이 값을 바탕으로 모의실험 및 실험을 통하여 제시한 모델의 타당성을 검증 하였다.

• 한국공간정보시스템학회:학술대회논문집
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• 2002.03a
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• pp.89-94
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• 2002

본 논문에서는 배전분야 설비관리 시스템을 대상으로 배전설비 고장시 GIS 기능을 이용하여 고장설비를 예측할 수 있는 방법과 구현 실례를 소개하고자 한다. 배전설비관리를 위한 지리정보 데이터 모델은 가공과 지중, 전기와 비전기, 점형과 선형의 특성을 가지는 배전설비의 특성을 분석하여 모델링된다. 모델링의 결과 생성된 데이터베이스는 실세계에 존재하는 대부분의 객체에 대한 정보를 포함하고 있으므로 매우 크고 그 구조 또한 복잡하다. 그러므로 응용프로그램이 필요로 하는 데이터를 추출하기 위하여 많은 시간이 요구된다. 그러나 고장복구업무를 위한 시스템은 사용자의 만족도를 위하여 추론의 정확성과 더불어 응답속도를 최소화하는 것이 필수조건이다. 이를 위하여 GIS 데이터베이스 모델을 좀 더 개량할 필요가 있으며, 본 논문에서는 이에 대한 한가지 방안으로 배전설비의 GIS 모델의 축약된 형태인 관계형 데이터베이스 모델을 제시한다. 고장점 추론은 이렇게 만들어진 축약모델을 이용하여 진행되며 고장신고 고객별로 회선, 개폐기, 변압기, 인입주 등 정보를 추출하고 추출된 설비들의 계통상 위치의 유사성을 추론하여 최종 예측점을 파악한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.249-255
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• 2011

The free-stereo mosaics image without GPS/INS and ground control data can be generated by using relative orientation parameters on the 3D model coordinate system. Its origin is located in one reference frame image. A 3D coordinate calculated by conjugate points on the free-stereo mosaic images is represented on the 3D model coordinate system. For determining 3D coordinate on the 3D absolute coordinate system utilizing conjugate points on the free-stereo mosaic images, transformation methodology is required for transforming 3D model coordinate into 3D absolute coordinate. Generally, the 3D similarity transformation is used for transforming each other 3D coordinates. Error of 3D model coordinates used in the free-stereo mosaic images is non-linearly increased according to distance from 3D model coordinate and origin point. For this reason, 3D model coordinates used in the free-stereo mosaic images are difficult to transform into 3D absolute coordinates by using linear transformation. Therefore, methodology for transforming nonlinear 3D model coordinate into 3D absolute coordinate is needed. Also methodology for resampling the free-stereo mosaic image to the geo-stereo mosaic image is needed for overlapping digital map on absolute coordinate and stereo mosaic images. In this paper, we propose a 3D non-linear transformation for converting 3D model coordinate in the free-stereo mosaic image to 3D absolute coordinate, and a 2D non-linear transformation based on 3D non-linear transformation converting the free-stereo mosaic image to the geo-stereo mosaic image.

• Journal of Korean Society of Forest Science
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• v.82 no.3
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• pp.292-304
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• 1993

This research developed a forest-level harvest scheduling model using linear programming (LP). The formulations of the LP model include timber production schemes with constraints of nondecling yield forest conversion strategies, the minimum timber supply, levels and the maximum cut acrages. The model is able to generate both Model I and Model II types of input matrix in MPS format. In this paper, use of LP in building the framework of the strategic forest planning model was justified by comparing the algorithmic characteristics of LP with those of Gentan probability and binary search approaches through literature reviews. In order to demonstrate the field applicability of the model proposed. (1) the harvest scheduling problem for about 11,000-hectare case study area (Mt. Baekun area in Southern Experimental Forest of Seoul National University) was formulated and soloed and (2) the effects of the change in task regulatory timber production constraints or. optimal harvesting schedules here investigated.

• Journal of KIISE:Databases
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• v.31 no.5
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• pp.479-491
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• 2004

Location information of mobile objects is applied to vehicle tracking, digital battlefields, location based services, and telematics. Their location coordinates are periodically measured and stored in the application systems. The linear function is mainly used to estimate the location information that is not in the system at the query time point. However, a new method is needed to improve uncertainties of the location representation, because the location estimation by linear function induces the estimation error. This paper proposes an application method of the cubic spline interpolation in order to reduce deviation of the location estimation by linear function. First, we define location information of the mobile object moving on the two-dimensional space. Next, we apply the cubic spline interpolation to location estimation of the proposed data model and describe algorithm of the estimation operation. Finally, the precision of this estimation operation model is experimented. The experimentation comes out more accurate results than the method by linear function, although the proposed location estimation function uses the small amount of information. The proposed method has an advantage that drops the cost of data storage space and communication for the management of location information of the mobile objects.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.511-517
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• 2010

The purpose of this study is to investigate the shear behavior of prestressed concrete deep beams and to provide the data for development of improved design criteria. The accuracy and objectivity of the assessment process may be enhanced by the use of sophisticated nonlinear finite element analysis program. Hence, in this study, the computer program, named RCAHEST (reinforced concrete analysis in higher evaluation system technology), was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. A bonded or unbonded tendon element based on the finite element method, that can represent the interaction between tendon and concrete of prestressed concrete member, is used. The proposed numerical method for the shear behavior of prestressed concrete deep beams is verified by comparing the analytical results with test data by others.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.3
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• pp.47-58
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• 1994

Theoretical calculations are carried out for the estimation of linear maneuvering coefficients of a ship moving in shallow water region. Hydrodynamic forces and moments acting on a maneuvering ship are modelled based on a slender body theory, from which integro-differential equation for the unknown inner stream velocity is derived. Numerical algorithms fur solving this equation are described in detail. By considering water depth effects in the mathematical model, variations of maneuvering coefficients with water depth are studied. Programs are developed according to this method and calculations are done for Mariner, Series 60 and Wigley hull forms. For the verification of the programs, calculated results are compared with some analytic solutions and with published experimental results, which show good agreements in spite of many assumptions included in the mathematical model. It is expected that this method can be used as a preliminary tool for the estimation of maneuverability coefficients of a ship in shallow water region at its initial design stage.