• 제목/요약/키워드: Minimal model

검색결과 664건 처리시간 0.033초

AMSAA Model을 이용한 최적 LCC에 관한 연구 (A Study on the Optimal LCC using AMSAA Model)

  • 김준홍
    • 산업경영시스템학회지
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    • 제29권3호
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    • pp.135-142
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    • 2006
  • Engineers are always concerned with life cycle costs for making important economic decisions through engineering action like reliability of products. Decisions during the reliability growth development of products involve trade-offs between invested costs and its returns. In order to find minimal LCC containing the reliability improvement cost, production cost, repair and replacement costs, and holding cost of spare parts for failure items we suggest in this paper relationship between development cost and sustaining cost in values of growth parameter $\beta$ of AMSAA model. This model is applied to the reliability growth program based on AMSAA model during R&D phase, the warranty activities of items and the block replacement policy for maintenance of items in avionic equipment.

폐암의 면역세포 치료: 동물 모델에서 수지상 세포를 이용한 Adjuvant Therapy 가능성 연구 (Immunocell Therapy for Lung Cancer: Dendritic Cell Based Adjuvant Therapy in Mouse Lung Cancer Model)

  • 이석재;김명주;인소희;백소영;이현아
    • IMMUNE NETWORK
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    • 제5권1호
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    • pp.36-44
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    • 2005
  • Background: The anti-tumor therapeutic effect of autologous tumor cell lysate pulseddendritic cells (DCs) was studied for non-immunogenic and immune suppressive lung cancer model. To test the possibility as an adjuvant therapy, minimal residual disease model was considered in mouse in vivo experiments. Methods: Syngeneic 3LL lung cancer cells were inoculated intravenously into the C57BL/6 mouse. Autologous tumor cell (3LL) or allogeneic leukemia cell (WEHI-3) lysate pulsed-DCs were injected twice in two weeks. Intraperitoneal DC injection was started one day (MRD model) after tumor cell inoculation. Two weeks after the final DC injection, tumor formation in the lung and the tumor-specific systemic immunity were observed. Tumor-specific lymphocyte proliferation and the IFN-${\gamma}$ secretion were analyzed for the immune monitoring. Therapeutic DCs were cultured from the bone marrow myeloid lineage cells with GM-CSF and IL-4 for 7 days and pulsed with tumor cell lysate for 18 hrs. Results: Compared to the saline treated group, tumor formation was suppressed in 3LL tumor cell lysate pulsed-DC treated group, while 3LL-specific immune stimulation was minimum. WEHI-3-specific immune stimulation occurred in WEHI-3 lysate-pulsed DC treated group, which had no correlation with tumor regression. Conclusion: The data suggest the possible anti-tumor effect of cultured DCs as an adjuvant therapy for minimal residual disease state of lung cancer. The significance of immune modulation in DC therapy including the possible involvement of NK cell as well as antigen-specific cytotoxic T cell activity induction was discussed.

Modeling, simulation and structural analysis of a fluid catalytic cracking (FCC) process

  • Kim, Sungho;Urm, Jaejung;Kim, Dae Shik;Lee, Kihong;Lee, Jong Min
    • Korean Journal of Chemical Engineering
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    • 제35권12호
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    • pp.2327-2335
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    • 2018
  • Fluid catalytic cracking (FCC) is an important chemical process that is widely used to produce valuable petrochemical products by cracking heavier components. However, many difficulties exist in modeling the FCC process due to its complexity. In this study, a dynamic process model of a FCC process is suggested and its structural observability is analyzed. In the process modeling, yield function for the kinetic model of the riser reactor was applied to explain the product distribution. Hydrodynamics, mass balance and energy balance equations of the riser reactor and the regenerator were used to complete the modeling. The process model was tested in steady-state simulation and dynamic simulation, which gives dynamic responses to the change of process variables. The result was compared with the measured data from operating plaint. In the structural analysis, the system was analyzed using the process model and the process design to identify the structural observability of the system. The reactor and regenerator unit in the system were divided into six nodes based on their functions and modeling relationship equations were built based on nodes and edges of the directed graph of the system. Output-set assignment algorithm was demonstrated on the occurrence matrix to find observable nodes and variables. Optimal locations for minimal addition of measurements could be found by completing the whole output-set assignment algorithm of the system. The result of this study can help predict the state more accurately and improve observability of a complex chemical process with minimal cost.

하천 내 유사와 인 이동에 관한 모델링 (Modeling of Sediment and Phosphorous Transport in a River Channel)

  • 김경현
    • 한국물환경학회지
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    • 제26권2호
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    • pp.332-342
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    • 2010
  • A model has been developed to investigate in-river sediment and phosphorus dynamics. This advective-dispersive model is coupled with hydrodynamics and sediment transport submodels to simulate suspended sediment, total dissolved phosphorus, total phosphorus, and particulate phosphorus concentrations under unsteady flow conditions. It emphasizes sediment and phosphorus dynamics in unsteady flow conditions, in which the study differs from many previous solute transport studies, conducted in relatively steady flow conditions. The diffusion wave approaximation was employed for unsteady flow simulations. The first-order adsorption and linear adsorption isotherm model was used on the basis of the three-layered riverbed submodel with riverbed sediment exchange and erosion/deposition processes. Various numerical methods were tested to select a method that had minimal numerical dispersion under unsteady flow conditions. The responses of the model to the change of model parameter values were tested as well.

EMPIRICAL REALITIES FOR A MINIMAL DESCRIPTION RISKY ASSET MODEL. THE NEED FOR FRACTAL FEATURES

  • Christopher C.Heyde;Liu, S.
    • 대한수학회지
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    • 제38권5호
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    • pp.1047-1059
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    • 2001
  • The classical Geometric Brownian motion (GBM) model for the price of a risky asset, from which the huge financial derivatives industry has developed, stipulates that the log returns are iid Gaussian. however, typical log returns data show a distribution with much higher peaks and heavier tails than the Gaussian as well as evidence of strong and persistent dependence. In this paper we describe a simple replacement for GBM, a fractal activity time Geometric Brownian motion (FATGBM) model based on fractal activity time which readily explains these observed features in the data. Consequences of the model are explained, and examples are given to illustrate how the self-similar scaling properties of the activity time check out in practice.

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Incremental Model-based Test Suite Reduction with Formal Concept Analysis

  • Ng, Pin;Fung, Richard Y.K.;Kong, Ray W.M.
    • Journal of Information Processing Systems
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    • 제6권2호
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    • pp.197-208
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    • 2010
  • Test scenarios can be derived based on some system models for requirements validation purposes. Model-based test suite reduction aims to provide a smaller set of test scenarios which can preserve the original test coverage with respect to some testing criteria. We are proposing to apply Formal Concept Analysis (FCA) in analyzing the association between a set of test scenarios and a set of transitions specified in a state machine model. By utilizing the properties of concept lattice, we are able to determine incrementally a minimal set of test scenarios with adequate test coverage.

Maximizing Mean Time to the Catastrophic Failure through Burn-In

  • Cha, Ji-Hwan
    • Journal of the Korean Data and Information Science Society
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    • 제14권4호
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    • pp.997-1005
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    • 2003
  • In this paper, the problem of determining optimal burn-in time is considered under a general failure model. There are two types of failure in the general failure model. One is Type I failure (minor failure) which can be removed by a minimal repair and the other is Type II failure (catastrophic failure) which can be removed only by a complete repair. In this model, when the unit fails at its age t, Type I failure occurs with probability 1 - p(t) and Type II failure occurs with probability p(t), $0{\leq}p(t)\leq1$. Under the model, the properties of optimal burn-in time maximizing mean time to the catastrophic failure during field operation are obtained. The obtained results are also applied to some illustrative examples.

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Engineering Valuation Based on Small Samples

  • Cho, Jin-Hyung;Lee, Sae-Jae;Seo, Bo-Chul
    • 산업경영시스템학회지
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    • 제29권1호
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    • pp.143-150
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    • 2006
  • Box-Cox model and T-factor method have been widely used to measure economic depreciations for industrial property. The Box-Cox model which combines economic efficiency with depreciation pattern is here extended to the reliability function. To do so a Rayleigh distribution which has been used to estimate the reliability of current assets was chosen as an efficiency curve of marginal productivity. Such an approach provides the possibility to classify the efficiency curves into four categories. It is also possible to analyze the types of depreciation curves. Therefore, the power family of a non-linear Box-Cox model could be set at certain constant values, then the model can be transformed into a linear model to estimate the economic depreciation rates by utilizing the reliability function. Estimating the resultant linear regression equation requires minimal number of observations, while at the same time facilitating the test of hypothesis on depreciation rates.

풍력단지의 발전량 추계적 모형 제안에 관한 연구 (Development of a Stochastic Model for Wind Power Production)

  • 류종현;최동구
    • 경영과학
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    • 제33권1호
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    • pp.35-47
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    • 2016
  • Generation of electricity using wind power has received considerable attention worldwide in recent years mainly due to its minimal environmental impact. However, volatility of wind power production causes additional problems to provide reliable electricity to an electrical grid regarding power system operations, power system planning, and wind farm operations. Those problems require appropriate stochastic models for the electricity generation output of wind power. In this study, we review previous literatures for developing the stochastic model for the wind power generation, and propose a systematic procedure for developing a stochastic model. This procedure shows a way to build an ARIMA model of volatile wind power generation using historical data, and we suggest some important considerations. In addition, we apply this procedure into a case study for a wind farm in the Republic of Korea, Shinan wind farm, and shows that our proposed model is helpful for capturing the volatility of wind power generation.

최소 침습적 충진 및 통상적 인레이 법으로 수복한 대구치의 응력 분포: 3-D 유한 요소 해석 (Stress distribution of molars restored with minimal invasive and conventional technique: a 3-D finite element analysis)

  • 양선미;김선미;최남기;김재환;양성표;양홍서
    • 구강회복응용과학지
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    • 제34권4호
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    • pp.297-305
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    • 2018
  • 목적: 다양한 형태의 공동 설계 및 재료를 이용한 하악 대구치의 치아 구조 및 intracoronal 수복물에서 발생하는 응력 분포 및 최대 von Mises 응력을 분석하고자 하였다. 연구 재료 및 방법: 콤포지트레진 및 금으로 수복한 통상적 교합면 와동과(OR-C, OG-C) 인접면 와동(MR-C, MG-C) 및 콤포지트레진으로 충전한 최소 침습적 와동을 갖는 교합면 와동(OR-M) 및 인접면 와동(MR-M)의 형상을 하악 삼차원 입체 모델로 설계했다. 저작력을 부여하기 위해 총 교합력 200 N의 정적 축 방향 하중을 10개의 교합 접촉점에서 치아에 적용했다. 유한 요소 해석은 교합 하중에 의해 생성 된 응력 분포를 예측하기 위해 수행되었다. 결과: 최소 침습적 설계를 가진 수복물은 통상적 와동 설계(341.9 MPa - 397.2 MPa)에 비해 von Mises 응력(OR-M 모델: 26.8 MPa, MR-M 모델: 72.7 MPa)의 값이 현저하게 낮았다. 치아 내부에서 최대 von Mises 응력의 크기는 통상적 와동 설계(372.8 - 412.9 MPa) 및 최소 와동 설계(361.1 - 384.4 MPa) 모델에서 유사했다. 결론: 최소 침습성 모델은 수복물 중에서 최소의 von Mises 응력이 생성되었다. 법랑질 내에서는 최대 von Mises 응력이 최소 공동 설계와 기존 설계의 모델에서 유사한 크기로 관찰되었다.