• 제목/요약/키워드: a model mismatch

검색결과 227건 처리시간 0.21초

시스템 다이내믹스 방법론을 이용한 정보보호인력 수급체계 분석 (System Dynamics Approach to Demand and Supply of Information Security Manpower)

  • 김태성;전효정;박상현;장석호
    • 한국통신학회논문지
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    • 제29권5C호
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    • pp.642-653
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    • 2004
  • 정보보호산업 성장의 가장 큰 애로요인 중 하나로 시장의 미성숙, 정보보호에 대한 인식 부족 등과 함께 전문 인력의 부족 등이 꼽히고 있는 가운데, 정보보호인력은 공급부족으로 인한 수급 불일치 현상을 보이고 있다. 이러한 현상은 산업에 대한 수요는 필연적으로 인력에 대한 수요를 발생시키게 되는데, 정보보호산업이 급속히 성장함에 따라 시기 적절한 정보보호인력의 양성 및 공급 대책을 수립함에 있어 어려움이 있었기 때문인 것으로 파악된다. 본 연구는 정보보호인력의 원활한 공급을 위해서는 정보보호인력의 수급체계에 대한 분석이 선행되어야 한다는 데에 초점을 두곤 시스템 다이내믹스 방법론(System Dynamics)을 이용하여 정보보호인력의 수급체계 분석을 위한 모형을 작성하였다. 모형 구현의 궁극적인 목표는 정보보호인력의 수급체계가 갖고 있는 형태를 분석해 보고자 하는 것이며, 이 때 주요정책변수를 조절하여 구현한 결과를 통해 정보보호인력의 원활한 공급을 위한 정책마련에 시사점을 주고자 한다.

퍼지-AHP를 활용한 구직자의 기업평가 모형 개선 연구 (An Improved Company Assessment Framework Based on Job Seekers' Preferences Using Fuzzy-Analytic Hierarchy Process(AHP))

  • 이충석;류옥현
    • 산업경영시스템학회지
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    • 제38권1호
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    • pp.90-100
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    • 2015
  • This study is conducted to suggest ways to mitigate the mismatch phenomenon between job seekers who want to find right company for themselves and companies looking for appropriate new employees. For this purpose, this study improves the company assessment framework reflecting job seekers interests by using fuzzy analytic hierarchy process. The improved evaluation framework is a three-level hierarchical structure, where there are 4 groups at the top level, 12 factors at the intermediate level and 36 indexes at the bottom level. For the empirical analysis of the applicants preferences based on the improved model, a survey for F-AHP analysis is carried out to university students and then priorities of components in the evaluation model are calculated. Moreover, the differences of priority of the company assessment framework are analyzed for different genders, college years, and major divisions. The results show that job seekers' most concerning factors are wages, stability, working environments, and labor deal, which are ranked highly in this order and the differences in preferences for each type of job seekers (genders, college years, and major divisions) are obvious. The results also show that the male prefers wages to environment, on the other hand female does working environment to wages.

Crack growth analysis and remaining life prediction of dissimilar metal pipe weld joint with circumferential crack under cyclic loading

  • Murthy, A. Ramachandra;Gandhi, P.;Vishnuvardhan, S.;Sudharshan, G.
    • Nuclear Engineering and Technology
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    • 제52권12호
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    • pp.2949-2957
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    • 2020
  • Fatigue crack growth model has been developed for dissimilar metal weld joints of a piping component under cyclic loading, where in the crack is located at the center of the weld in the circumferential direction. The fracture parameter, Stress Intensity Factor (SIF) has been computed by using principle of superposition as KH + KM. KH is evaluated by assuming that, the complete specimen is made of the material containing the notch location. In second stage, the stress field ahead of the crack tip, accounting for the strength mismatch, the applied load and geometry has been characterized to evaluate SIF (KM). For each incremental crack depth, stress field ahead of the crack tip has been quantified by using J-integral (elastic), mismatch ratio, plastic interaction factor and stress parallel to the crack surface. The associated constants for evaluation of KM have been computed by using the quantified stress field with respect to the distance from the crack tip. Net SIF (KH + KM) computed, has been used for the crack growth analysis and remaining life prediction by Paris crack growth model. To validate the model, SIF and remaining life has been predicted for a pipe made up of (i) SA312 Type 304LN austenitic stainless steel and SA508 Gr. 3 Cl. 1. Low alloy carbon steel (ii) welded SA312 Type 304LN austenitic stainless-steel pipe. From the studies, it is observed that the model could predict the remaining life of DMWJ piping components with a maximum difference of 15% compared to experimental observations.

인재매칭을 위한 내용기반 척도학습모형의 설계 (A Design of Content-based Metric Learning Model for HR Matching)

  • 송희석
    • Journal of Information Technology Applications and Management
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    • 제27권6호
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    • pp.141-151
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    • 2020
  • The job mismatch between job seekers and SMEs is becoming more and more intensifying with the serious difficulties in youth employment. In this study, a bi-directional content-based metric learning model is proposed to recommend suitable jobs for job seekers and suitable job seekers for SMEs, respectively. The proposed model not only enables bi-directional recommendation, but also enables HR matching without relearning for new job seekers and new job offers. As a result of the experiment, the proposed model showed superior performance in terms of precision, recall, and f1 than the existing collaborative filtering model named NCF+GMF. The proposed model is also confirmed that it is an evolutionary model that improves performance as training data increases.

한국 해양환경에서 음파전달모델을 이용한 표적기동분석 알고리즘 (Target motion analysis algorithm using an acoustic propagation model in the ocean environment of South Korea)

  • 서기훈
    • 한국음향학회지
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    • 제38권4호
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    • pp.387-395
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    • 2019
  • 수동소나에서의 표적기동분석은 방위 또는 방위-주파수와 같이 제한된 정보를 이용하여 수행된다. 표적기동분석을 빠르고 정확하게 수행하기 위해서는 정확한 표적기동 초기치의 추정이 필수적이다. 기존의 표적기동분석과 달리 신호 대 잡음비 정보와 음파전달모델을 추가로 이용하면 표적기동분석의 정확도를 향상시킬 수 있다. 이 방법은 표적의 방사소음수준은 알고 있다고 가정하지만 가정한 수준과 실제 수준간의 오차에 따라 표적기동분석의 정확도가 저하될 수 있다. 본 논문에서는 수동 소나로 탐지한 표적 방위정보, 탐지 신호 대 잡음비 정보 및 음파전달모델을 이용한 표적기동분석 알고리즘을 한국 해양환경(동해/서해/남해)에서 수행한다. 그리고 가정한 표적 방사소음수준과 실제 수준간의 차이에 따른 성능분석 결과를 제시한다.

근사화된 2계 모델을 이용한 시간지연 시스템의 제어기 설계 (Design of the Controllers for Time-Delay Systems Using the Approximated 2nd-Order Model with Dead-Time)

  • 김종훈;박종식;양승현;이석원
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 D
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    • pp.2164-2166
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    • 2002
  • This paper present a controller design scheme for time-delay system. The Smith Predictor has been proposed to solve the problem of time-delay. But this structure has a condition that parameters of plant and model have to be matched accurately. Because of this condition, it is not applied broadly in practical industrial process field. In this paper, the 2nd-order model with dead-time is used as plant model of the Smith Predictor and a main controller is designed by using the effect of mismatch between plant and model.

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Robust Predictive Speed Control for SPMSM Drives Based on Extended State Observers

  • Xu, Yanping;Hou, Yongle;Li, Zehui
    • Journal of Power Electronics
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    • 제19권2호
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    • pp.497-508
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    • 2019
  • The predictive speed control (PSC) strategy can realize the simultaneous control of speed and current by using one cost function. As a model-based control method, the performance of the PSC is vulnerable to model mismatches such as load torque disturbances and parameter uncertainties. To solve this problem, this paper presents a robust predictive speed control (RPSC) strategy for surface-mounted permanent magnet synchronous motor (SPMSM) drives. The proposed RPSC uses extended state observers (ESOs) to estimate the lumped disturbances caused by load torque changes and parameter mismatches. The observer-based prediction model is then compensated by using the estimated disturbances. The introduction of ESOs can achieve robustness against predictive model uncertainties. In addition, a modified cost function is designed to further suppress load torque disturbances. The performance of the proposed RPSC scheme has been corroborated by experimental results under the condition of load torque changes and parameter mismatches.

Development of Composite Load Models of Power Systems using On-line Measurement Data

  • Choi Byoung-Kon;Chiang Hsiao Dong;Li Yinhong;Chen Yung Tien;Huang Der Hua;Lauby Mark G.
    • Journal of Electrical Engineering and Technology
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    • 제1권2호
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    • pp.161-169
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    • 2006
  • Load representation has a significant impact on power system analysis and control results. In this paper, composite load models are developed based on on-line measurement data from a practical power system. Three types of static-dynamic load models are derived: general ZIP-induction motor model, Exponential-induction motor model and Z-induction motor model. For the dynamic induction motor model, two different third-order induction motor models are studied. The performances in modeling real and reactive power behaviors by composite load models are compared with other dynamic load models in terms of relative mismatch error. In addition, numerical consideration of ill-conditioned parameters is addressed based on trajectory sensitivity. Numerical studies indicate that the developed composite load models can accurately capture the dynamic behaviors of loads during disturbance.

수정 Eshelby등가 개재물 방법을 이용한 단섬유 금속 복합재료의 열적잔류응력의 해석에 관한 연구

  • 손봉진;이준현;김문생
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1993년도 추계학술대회 논문집
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    • pp.660-665
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    • 1993
  • An elastic model is developed to predict the average thermal residual stresses in the matrix and fiber of a misoriented short fiber composite. The thermal residual stresses are induced by the mismatch in the coefficient of the thermal expansion of the matrix and fiber when the composite is subjected to a uniform temperature change. The model considers two special cases of fiber misorientation ; two-dimensional in-plane and three-dimensional axisymmetric. The analytical formulation of the model is based on Eshelby's equivalent inclusion method and is nuque in that it is able to account for interactions among fibers. The model is more general than past models and it is able to treat prior analyses of the simpler composite systems as extram cases. The present model is to investigate the effects of fiber volume fraction, distribution type, distribution cut-off angle, and aspect ratio on thermal residual stress for both in-plane and axisymmetric fiber misorientation. Fiber volum fraction, aspect ratio, and disturbution cut-off angle are shown to have more significant effects on the magnitude of the thermal residual stress than fiber distrubution type for both in-plane and axisymmetric misorientation.

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뉴로 퍼지 시스템을 이용한 비선형 시스템의 IMC 제어기 설계 (Design of IMC for Nonlinear Systems by Using Adaptive Neuro-Fuzzy Inference System)

  • 김성호;강정규
    • 제어로봇시스템학회논문지
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    • 제7권11호
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    • pp.958-961
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    • 2001
  • Control of Industrial processes is very difficult due to nonlinear dynamics, effect of disturbances and modeling errors. M.Morari proposed Internal Model Control(IMC) system that can be effectively applied to the systems with model uncertainties and time delays. The advantage of IMC is their robustness with respect to a model mismatch and disturbances. But it is difficult to apply for nonlinear systems. ANFIS(Adaptive Neuro-Fuzzy Inference System) which contains multiple linear models as consequent part is used to model nonlinear systems. Generally, the linear parameters in ANFIS can be effectively utilized to control a nonlinear systems. In this paper, we propose new ANFIS-based IMC controller for nonlinear systems. Numerical simulation results show that the proposed control scheme has good performances.

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