• Title, Summary, Keyword: 가역접근법

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Nonlinear Forecasting of Daily Runoff Using Inverse Approach Method (가역접근법을 이용한 일유출량 자료의 비선형 예측)

  • Jeong, Dong Kug;Lee, Bae Sung
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.1178-1182
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    • 2004
  • 시계열 자료의 분석과 예측은 수문학분야에서 매우 중요하면, 최근 들어 특정한 수문시계열에서 카오스 특성이 발견되고 있다. 카오스 특성을 갖는 수문시계열의 예측에 있어, 기존의 거의 모든 연구는 시스템의 특성을 파악한 뒤 예측을 실시하는 표준접근법이 채택되어왔다. 그러나 Phoon 등은 시스템의 특성분석에 앞서 예측을 실시하고, 상태공 매개변수가 시스템의 특성분석단계가 아닌 예측단계에서 평가되는 가역접근법을 제안하였다. 본 연구에서는 Phoon 등이 제안한 가역접근법과 기존에 널리 적용되어온 표준접근법을 실제 일유출량 자료에 적용함으로써, 가역접근법의 적용성을 검토하고 카오스 시계열의 특성을 파악하였다. 본 연구에서 사용한 비선형 예측 기법으로는 카오스이론이 적용된 부분근사화 기법을 이용하였다. 카오스 특성분석을 통해, Bear 강 일유출량 시계열 자료에서 카오스 특성이 나타남을 알 수 있었다. 표준접근법과 가역접근법을 이용하여 Bear 강의 일유출량 자료에 대하여 예측을 실시한 결과, 카오스 특성을 갖는 일유출량 시계열 자료의 단기 예측의 우수성을 알 수 있었으면, 가역접근법이 표준접근법에 비해 좋은 결과를 나타내었다. 특히, 가역접근법은 예측단계에서 예측시간(T)에 대하여 예측매개변수를 최적화시킴으로써 보다 정밀한 예측을 할 수 있었으며, 시스템에 대한 정보손실이 발생하였을 경우 예측에 대한 상태공간 매개변수를 다시 추정해야 하는 표준접근법에 비해 실제적 적용성이 매우 우수하였다.

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Nonlinear Forecasting of Daily Runoff Using Inverse Approach Method (가역접근법을 이용한 일유출량 자료의 비선형 예측)

  • Lee, Bae-Sung;Jeong, Dong-Kug;Jung, Tae-Sung;Lee, Sang-Jin
    • Journal of Korea Water Resources Association
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    • v.39 no.3
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    • pp.253-259
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    • 2006
  • In almost all previous hydrological studies, the standard approach adopted for nonlinear time series analysis is to perform system characterization first followed by forecasting. However, a practical inverse approach for forecasting nonlinear hydrological time series was proposed recently To investigate the applicability standard approach method and inverse approach, this study used a theoretical time series (Mackey-Glass time series) and daily streamflows of the Bear River in Idaho. To predict a theoretical time series and daily streamflow, this study used local approximation method. From chaos analysis, chaotic characteristics are found in daily streamflow of the Bear River in Idaho. Resulting from 1, 3 and 5-day prediction, inverse approach method is shown to be better than the standard approach for a theoretical chaotic time series and daily streamflow.

An Analysis of the Wave Properties in an Inhomogeneous Anisotropic Medium using Variational Reaction Theory (변분 리액션 이론을 이용한 비균질 비등방성 매질에서의 전파특성 해석)

  • 김현준;홍용인;김정기
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.10
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    • pp.1461-1468
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    • 1993
  • In this paper the propagation problem of waves obliquely incident upon an anisotropic medium with arbitrary permittivity tensors is analyzed through a partial variational finite element method. First, a variational equation is derived from the new approach based on the induction theorem, reactions, and reciprocity. Next, by using the finite element method, the propagation problems are solved from the obtained functional. Also included are numerical results for the problem of waves incident upon a magnetoplasma slab.

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Rat의 실험적 건망 모델에 있어 항치매 효과물질의 약효 검색에 관한 연구

  • 이영근;류항묵;김옥희;양지선;이숙영;노용남;강석연
    • Proceedings of the Korean Society of Applied Pharmacology
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    • pp.161-161
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    • 1993
  • 중추 Cholinergic성 신경계 작용약의 유발한 치매동물 모델의 타당성 여부를 확인하기 위해 흰쥐에 Scopolamine, Physostigmine 및 생약을 반복 투여하였을 때의 active avoidance에 미치는 영향을 단회 투여하여 가역적인 작용을 가질때의 영향과 비교하고 이때 대뇌피질에서의 Cholinergic성 신경계의 활성 변화를 측정하여 중추 Cholinergic성 신경계의 학습, 기억 과정에서의 역할 및 나아가 치매의 발생 원인 및 발병 져로 규명에 접근하고자 하였다. 6 주된 Wistar계 웅성 래트에 Cholinergic성 신경계 작용약인 Scopolamine(1 mg/kg), Posostigmine (0.1mg/kg)과 생약인 Ginseng Total Saponine(100 mg/kg), 오미자 추출물 (150 mg/kg)등을 단독 혹은 병용으로 피하와 복강내로 7 일간 반복 투여하면서 Shuttle Box를 이용하여 Active Avoidance 의 습득율을 측정하고 이후 실험동물을 단두치사하여 대뇌피질 영역에서의 Acetylcholine 농도와 Acetylcholinesterase 활성 변화를 Chemi luminosence 법을 이용하여 측정하였다.

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Wave propagation in an Inhomogeneous Anisotropic Medium through Variational Finite Element Method (변분 유한요소법에 의한 비균질 비등방성 매질에서의 전파특성)

  • 김현준;홍용인;김두경;김정기
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.3 no.1
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    • pp.33-41
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    • 1992
  • In this paper the propagation problems of waves nomally incident upon an anisotropic medium with arbitrary permittivity tensors are analyzed through the variational finite element method. First, a variational equation is derived from the new approach basd on the induction theorm, reactions, and reciprocity. Next, by using the finite element method, the propagation problems are solved from the obtained functional. Specially, the reflection and transmission coefficient and axis ratio are obtained on the case of normally incident upon a homogeneous and inhomogeneous anisotropic medium such as cold mgnetoplasma slab and showed agreement with those of the previous method.

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Clinical assessment to the dental treatment of bruxism: literature review (이갈이 환자의 치과 치료에 관한 임상적 접근을 위한 문헌 고찰)

  • Choi, Yu-Sung
    • Journal of Dental Rehabilitation and Applied Science
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    • v.30 no.1
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    • pp.36-44
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    • 2014
  • Bruxism is a much-discussed clinical issue in dentistry. Although bruxism is not a life-threatening disorder, it can influence the quality of human life, especially through dental problems, such as, frequent fractures of dental restorations and pain in the orofacial region. This research has a goal to investigate the diagnostic methods of bruxism, to provide an appropriate information about various treatment in clinical situation, and to evaluate the effect and the usefulness of those methods. There is no certain remedy for bruxism that is a technically efficient and definitely reliable diagnosis and treatment. So, the primary purpose is to prevent the oral and maxilofacial tissue injuries from bruxism and to relieve the pain and symptom. Therefore, Combining various reversible treatments together, such as behavior modification, Oral appliances therapy and physiotherapy, is recommended. For a bruxism treatment in dental field, more researches about the factors influencing on diagnosis and cure are necessary.

Equivalent Network Modeling of Slot-Coupled Microstripline to Waveguide Transition (슬롯 결합 마이크로스트립라인-도파관 천이기의 등가 회로 모델링)

  • Kim Won-Ho;Shin Jong-Woo;Kim Jeong-Phill
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.10
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    • pp.1005-1010
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    • 2004
  • An analysis method of slot-coupled microstripline to waveguide transition is presented to developed a simple but accurate equivalent circuit model. The equivalent circuit consists of an ideal transformer, microstrip open stub, and admittance elements looking into a waveguide and a half space of feed side from a slot center. The related circuit element values are calculated by applying the reciprocity theorem, the Fourier transform and series representation, the complex power concept, and the spectral-domain immittance approach. The computed scattering parameters are compared with the measured, and good agreement validates the simplicity and accuracy of the proposed equivalent circuit model.

Alignment change of lipid molecules in lipid bilayers by an antimicrobial peptide protegrin-1 (지질 이중막에 결합된 항균성 펩타이드 protegrin-1에 의한 지질 분자의 정열도 변화)

  • Kim, Chul
    • Analytical Science and Technology
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    • v.28 no.2
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    • pp.106-111
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    • 2015
  • Changes in antimicrobial peptide-lipid mixtures were investigated using 31P solid-state nuclear magnetic resonance spectroscopy. An antimicrobial peptide, protegrin-1, and phosphatidylcholine were deposited on a thin cover glass and incubated under a relative humidity of 95%. The changes in the mixtures were observed after hydration or air-drying. How repetitive hydration and drying changed the phase of the sample was also observed. The degrees of disruption of the well-aligned bilayers of phosphatidylcholine were determined quantitatively by simulating the experimental spectra. The peptide-lipid mixtures changed reversibly after hydration and drying, and the samples reached an equilibrium state after several repetitions.

Finite Element Analysis of Edge Fracture of Electrical Steel Strip in Reversible Cold Rolling Mill (가역식 냉간 압연기에서 전기강판의 에지 파단에 관한 유한요소해석)

  • Byon, Sang Min
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.12
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    • pp.1619-1625
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    • 2012
  • An electrical steel strip is commonly used as a core material in all types of electric transformers and motors. It is produced by a cold rolling process. In this paper, a damage-mechanics-based approach that predicts the edge fracture of an electrical steel strip during cold rolling is presented. We adopted the normal tensile stress criterion and the fracture energy method as a damage initiation criterion and a damage evolution scheme, respectively. We employed finite element analysis (FEA) to simulate crack initiation and propagation at the initial notch located at the edges of the strip. The material constants required in FEA were experimentally obtained by tensile tests using a standard and a notched sheet-type specimen. The results reveal that the edge crack was initiated at the entrance of the roll bite and that it rapidly evolved at the exit. The evolution length of the edge crack increased as the length of the initial notch as well as the front tension reel force of the strip increased.

An Empirical Evaluation Scheme for Pedestrian Environment by Integrated Approach to TOD Planning Elements (TOD 계획 요소의 통합적 접근을 통한 친보행 환경의 평가 방안)

  • Joo, Yong-Jin;Ha, Eun-Ji;Jun, Chul-Min
    • Spatial Information Research
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    • v.20 no.3
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    • pp.15-25
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    • 2012
  • In order to resolve transportation system focused on vehicles which have led to all sorts of problems such as traffic congestion, air pollution and so on, Korea recently have tended to center around Transit Oriented Development(TOD) which is capable of initiating public traffic demands. It is imperative to develop objective evaluation method which is able to measure pedestrian environment and amenity in order to facilitate green transit. The purpose of this paper is to present evaluation indices and measurement framework of pedestrian environment by analyzing effect on TOD major planning factors such as diversity, density, design, and supply etc. For this, we applied evaluation index with regard to TOD planning factors, investigating connection to pedestrian and employed AHP (Analytic Hierarchy Process) so as to quantify the result of measurement in Jongro 3ga and Hangangjin station. As a result, we presented relationship between travel patterns of pedestrian and each TOD planning factor. More importantly, the proposed framework is expected to make the best of the visualization as well as evaluation method for the pedestrian accessibility, convenience of public transportation, and the mixed land-use patterns in subway area and transit center.