• 제목/요약/키워드: multi-level analysis

검색결과 1,546건 처리시간 0.028초

강유전성 물질을 이용한 Multi-level FeRAM 구조 및 동작 분석 (Multi-Level FeRAM Utilizing Stacked Ferroelectric Structure)

  • 공석헌;김준형;홍슬기
    • 마이크로전자및패키징학회지
    • /
    • 제30권3호
    • /
    • pp.73-77
    • /
    • 2023
  • 본 연구에서는 서로 다른 강유전성 물질을 활용하여 Multi-level FeRAM (Ferroelectrics random access memory) 소자에 대한 구조를 제시하였으며, 이를 검증하기 위해 Simulation을 통한 C-V 분석을 수행하였습니다. Multi-level 소자를 구현하기 위해 두 가지 서로 다른 물성을 가진 강유전체를 동일한 하부 전극 위에 나란히 증착하고, 이후 게이트 전극을 위에 올린 MFM (Multi-Ferroelectric Material) 구조를 제안하였습니다. 두 강유전체가 서로 다른 전압 조건에서 분극 현상 (Polarization)을 나타내는 것을 바탕으로, 두 개의 물질 중 한 개만 polarization 되었을 때와 두 개 모두 polarization 되었을 때의 상황을 C-V peak 분석을 통해 확인하여 Multi-level 동작을 구현할 수 있음을 확인하였습니다. 더불어, 제시한 구조를 반도체 제조 공정을 활용하여 구현하는 방법을 공정 simulation을 통해 검증하였습니다. 이러한 결과는 하나의 메모리 셀에서 여러 상태 값을 저장할 수 있음을 의미하며, 이는 메모리의 집적도를 크게 향상시킬 수 있는 새로운 구조체로서의 가능성을 의미합니다.

Multi-trade Prefabrication 기법 적용을 위한 기술적 요구사항 분석 (Analysis of Technical Requirement for Implementation of Multi-trade Prefabrication)

  • 장세준;이강
    • 한국건축시공학회:학술대회논문집
    • /
    • 한국건축시공학회 2016년도 춘계 학술논문 발표대회
    • /
    • pp.113-114
    • /
    • 2016
  • This paper proposes a technical requirements analysis of implementation of multi-trade prefabrication. Recently, there has been a rise in the use of prefabrication to minimize on-site work for time reduction to increase productivity. Prefabrication technique is evolved into multi-trade prefabrication combining other trades from single-trade prefabrication. For implementation of new technique, not only itself but complementary techniques have to be prepared. In this paper, MEP corridor rack, a major item of multi-trade prefabrication, was implemented in the test bed and its process was analyzed to find out technical requirements. As a result, comparatively high level of IT technique was required for efficient use of multi-trade prefabrication in design, lifting and construction phase. In design phase, component level of BIM library was needed for manufacturing; and in lifting phase, BIM-based site logistics process was required. Also in construction phase, laser scanning was implemented for gathering shape and geometry of the wall and slab that were attached to multi-trade prefabrication module.

  • PDF

Multi-unit Level 3 probabilistic safety assessment: Approaches and their application to a six-unit nuclear power plant site

  • Kim, Sung-yeop;Jung, Yong Hun;Han, Sang Hoon;Han, Seok-Jung;Lim, Ho-Gon
    • Nuclear Engineering and Technology
    • /
    • 제50권8호
    • /
    • pp.1246-1254
    • /
    • 2018
  • The importance of performing Level 3 probabilistic safety assessments (PSA) along with a general interest in assessing multi-unit risk has been sharply increasing after the Fukushima Daiichi nuclear power plant (NPP) accident. However, relatively few studies on multi-unit Level 3 PSA have been performed to date, reflecting limited scenarios of multi-unit accidents with higher priority. The major difficulty to carry out a multi-unit Level 3 PSA lies in the exponentially increasing number of multi-unit accident combinations, as different source terms can be released from each NPP unit; indeed, building consequence models for the astronomical number of accident scenarios is simply impractical. In this study, a new approach has been developed that employs the look-up table method to cover every multi-unit accident scenario. Consequence results for each scenario can be found on the table, established with a practical amount of effort, and can be matched to the frequency of the scenario. Preliminary application to a six-unit NPP site was carried out, where it was found that the difference between full-coverage and cut-off cases could be considerably high and therefore influence the total risk. Additional studies should be performed to fine tune the details and overcome the limitations of the approach.

국내 전력계통 안정화를 위한 다단계 부하차단 제어전략 수립에 관한 연구 (A Study on Multi Level Load Shedding Control Scheme Strategy for Stabilization of the Korean Power System)

  • 이윤환
    • 전기학회논문지P
    • /
    • 제65권4호
    • /
    • pp.255-261
    • /
    • 2016
  • Korean Power System are operating a load shedding system to prevent voltage instability phenomenon caused by severe line contingencies. In order to apply the load shedding scheme should be selected a location, amount, delay time. Current load shedding system is load shedding amount that has been calculated in the steady-state analysis to load shed the total amount in first level, load shedding amount calculated in advance, it is possible to perform an unnecessary load shedding. In this paper, set a multi-level load shedding control strategy step-by-step selection of load shedding amount for the prevention of excessive load shedding. In addition, through a voltage resilience analysis of the power system by applying motor load ratio and sensitivity parameter to selection the multi level load shedding ratio and delay time. For this reason, to take advantage of the limit data of interchange power, by utilizing interface power flow data to set a multi-level load shedding control strategy for the stabilization of the Korean Power System.

A Multi-Level Simulation Technique for Large-ScaleAnalog Integrated Circuits

  • Yang Jeemo
    • 한국산업정보학회:학술대회논문집
    • /
    • 한국산업정보학회 1998년도 공동추계학술대회 경제위기 극복을 위한 정보기술의 효율적 활용
    • /
    • pp.827-834
    • /
    • 1998
  • This paper describes a multi-level simulation technique and its implementation, which accurately solve voltages and currents of circuits descreibed at mixed levels of abstractions. A metho to form a tightly coupled simulation environment is proposed and, starting from a description of a circuit, simulation set-up and analysis procedure of the multi-level simulator for a transient response are presented. Circuit and behavioral simulation techniques and their implementations composing the multi-level simulation are explained in detail. Most of the algorithms implemented in the simulation are based upon the standard simulation techniques in order to obtain the reliability and accuracy of conventinoal simulators. Simulation examples show that the multi-level simulator can analyze circuits containing highly nonlinear behavioral models without loss of accuracy provided the behavioral models are accurate enough.

The transient and frequency response analysis using the multi-level system condensation in the large-scaled structural dynamic problem

  • Baek, Sungmin;Cho, Maenghyo
    • Structural Engineering and Mechanics
    • /
    • 제38권4호
    • /
    • pp.429-441
    • /
    • 2011
  • In large-scale problem, a huge size of computational resources is needed for a reliable solution which represents the detailed description of dynamic behavior. Recently, eigenvalue reduction schemes have been considered as important technique to resolve computational resource problems. In addition, the efforts to advance an efficiency of reduction scheme leads to the development of the multi-level system condensation (MLSC) which is initially based on the two-level condensation scheme (TLCS). This scheme was proposed for approximating the lower eigenmodes which represent the global behavior of the structures through the element-level energy estimation. The MLSC combines the multi-level sub-structuring scheme with the previous TLCS for enhancement of efficiency which is related to computer memory and computing time. The present study focuses on the implementation of the MLSC on the direct time response analysis and the frequency response analysis of structural dynamic problems. For the transient time response analysis, the MLSC is combined with the Newmark's time integration scheme. Numerical examples demonstrate the efficiency of the proposed method.

다중분할구조기법을 이용한 병렬전단벽의 효율적인 비선형 해석 (Effective Nonlinear Analysis of Coupled Wall Structures using Multi-Level Substructuring)

  • 김호수;홍성목;윤성준
    • 한국전산구조공학회:학술대회논문집
    • /
    • 한국전산구조공학회 1994년도 봄 학술발표회 논문집
    • /
    • pp.65-72
    • /
    • 1994
  • This study presents the application of multi-level substructuring for the effective nonlinear analysis of coupled wall structures. Also, the transition elements with 8 or 12 d. o. f, 5-node plane stress elements and concrete nonlinear model are considered as the basic finite elements of substructuring. In particular, the concept of localized nonlinearity is considered for the probable nonlinear zones of the structure, and the effective bottom-up and top-down process are presented through connectivity trees. The nonlinear analysis based on localized nonlinearity and multi-level substructuring, compared with the complete nonlinear analysis of the structure, gives the greater saving effects in computational efforts and cost.

  • PDF

TOPSIS와 전산직교배열을 적용한 자동차 로워암의 다수준 형상최적설계 (Multi-level Shape Optimization of Lower Arm by using TOPSIS and Computational Orthogonal Array)

  • 이광기;한승호
    • 한국정밀공학회지
    • /
    • 제28권4호
    • /
    • pp.482-489
    • /
    • 2011
  • In practical design process, designer needs to find an optimal solution by using full factorial discrete combination, rather than by using optimization algorithm considering continuous design variables. So, ANOVA(Analysis of Variance) based on an orthogonal array, i.e. Taguchi method, has been widely used in most parts of industry area. However, the Taguchi method is limited for the shape optimization by using CAE, because the multi-level and multi-objective optimization can't be carried out simultaneously. In this study, a combined method was proposed taking into account of multi-level computational orthogonal array and TOPSIS(Technique for Order preference by Similarity to Ideal Solution), which is known as a classical method of multiple attribute decision making and enables to solve various decision making or selection problems in an aspect of multi-objective optimization. The proposed method was applied to a case study of the multi-level shape optimization of lower arm used to automobile parts, and the design space was explored via an efficient application of the related CAE tools. The multi-level shape optimization was performed sequentially by applying both of the neural network model generated from seven-level four-factor computational orthogonal array and the TOPSIS. The weight and maximum stress of the lower arm, as the objective functions for the multi-level shape optimization, showed an improvement of 0.07% and 17.89%, respectively. In addition, the number of CAE carried out for the shape optimization was only 55 times in comparison to full factorial method necessary to 2,401 times.

주문 인도기간이 불확실한 상황에서의 (Q, r) 재고 부형과 다단계 분배 시스템의 응용에 관한 연구 (A Study on the (Q, r) Inventory Model under the Lead Time Uncertainty and its Application to the Multi-level Distribution System)

  • 강석호;박광태
    • 한국경영과학회지
    • /
    • 제11권1호
    • /
    • pp.44-50
    • /
    • 1986
  • In this paper, we find optimal policy for the (Q, r) inventory model under the lead time uncertainty. The (Q, r) inventory model is such that the fixed order quantity Q is placed whenever the level of on hand stock reaches the reorder point r. We first develop the single level inventory model as the basis for the analysis multi-level distribution systems. The functional problem is to determine when and how much to order in order to minimize the expected total cost per unit time, which includes the set up, inventory holding and inventory shortage cost. The model, then, is extended to the multi-level distribution system consisting of the factory, warehouses and retailers. In this case, we also find an optimal policy which minimizes the total cost of the contralized multi-level distribution system.

  • PDF

지진하중을 받는 다층 뼈대구조물의 다목적 최적설계 (Multi-Objective Optimization of Multistory Shear Building Under Seismic Loads)

  • 조효남;민대홍;정봉교
    • 한국전산구조공학회:학술대회논문집
    • /
    • 한국전산구조공학회 2002년도 가을 학술발표회 논문집
    • /
    • pp.255-262
    • /
    • 2002
  • In this paper, an improved multi-objective optimmum design method is proposed. And it is applied to steel frames under seismic loads. The multi-objective optimization problem is formulated with three optimality criteria, namely, minimum structural weight and maximum strain energy and stability. The Pareto curve can be obtained by performing the multi-objective optimization for multistory shear buildings. In order to efficiently solve the multi-objective optimization problem the decomposition method that separates both system-level and element-level is used. In addition, various techniques such as effective reanalysis technique with respect to intermediate variables and sensitivity analysis using an automatic differentiation (AD) we incorporated. Moreover, the relationship function among section properties induced from the profile is used in order to link system-level and element level. From the results of numerical investigation, it may be stated that the proposed method will lead to the more rational design compared with the conventional one.

  • PDF