• Title/Summary/Keyword: Mixed method approach

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Probability-Based Estimates of Basic Design Wind Speeds In Korea (확률에 기초한 한국의 기본 설계풍속 주정)

  • 조효남;백현식;차철준
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1988.10a
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    • pp.7-12
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    • 1988
  • This study presents rational methods for probability-based estimates of basic design wind speeds in Korea and develops a risk-bases nation-wide map of design wind speeds. The paper examines the fitting of the Type-I extreme model to maximum yearly non-typhoon wind data from long-term records based on the conventional method and to maximum monthly nod-typhoon wind data from short-term records following Grigorin's approach. The paper also reviews the applicability of the method using short records of about 5 years. The basic design wind speeds for typhoon and non-typhoon wind at a station are made to be obtained from a mixed model which is given as a product of typhoon and non-typhoon extreme wind distributions. A practical method which is based on the fitting of the Type I model to records or typhoon and non-typhoon mixed wind data at a station is also preposed in this study.

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Optimal Routing of Distribution System Planning using Hopfield Neural Network (홉필드 신경회로망을 이용한 배전계통계획의 최적 경로 탐색)

  • Kim, Dae-Wook;Lee, Myeong-Hwan;Kim, Byung-Seop;Shin, Joong-Rin;Chae, Myung-Suk
    • Proceedings of the KIEE Conference
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    • 1999.07c
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    • pp.1117-1119
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    • 1999
  • This paper presents a new approach for the optimal routing problem of distribution system planning using the well known Hopfield Neural Network(HNN) method. The optimal routing problem(ORP) in distribution system planning(DSP) is generally formulated as combinational mixed integer problem with various equality and inequality constraints. For the exceeding nonlinear characteristics of the ORP most of the conventional mathematical methods often lead to a local minimum. In this paper, a new approach was made using the HNN method for the ORP to overcome those disadvantages. And for this approach, a appropriately designed energy function suited for the ORP was proposed. The proposed algorithm has been evaluated through the sample distribution planning problem and the simulation results are presented.

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Effects of Stacking Sequence on the Application of the Single Specimen Technique to CLS Specimen (단일시편방법의 CLS 시편 적용시 적층성이 미치는 영향)

  • Lee, Gyeong-Yeop;Yang, Jun-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.23 no.11 s.170
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    • pp.1952-1959
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    • 1999
  • The work factor approach, so-called single specimen technique could be used to determine energy release rate from a single test record for unidirectional CLS specimen. In the present study, the work factor approach was extended to determine the mixed-mode fracture toughness of multi-directional graphite/epoxy laminated composites. Multi-directional CLS specimens were used for fracture tests. The stacking sequences used for the lap and the strap were $[90_2/0_2]_s/[0_4/90_4]_s$ and $[0/\pm45/0]_s/[0_2/\pm45_2/0_2]_2$, respectively. For both cases, the fracture toughness determined from the work factor approach was compared with that determined from the compliance method. It was found that both methods produced fracture toughness within a maximum 15% difference for each stacking sequence. The fractography analysis also showed that the fiber bridging occurred for$[0/\pm45/0]_s/[0_2/\pm45_2/0_2]_2$ case while it did not occur for $[90_2/0_2]_s/[0_4/90_4]_s$ case.

A Hybrid Heuristic Approach for Supply Chain Planningwith n Multi-Level Multi-Item Capacitated Lot Sizing Model (자원제약하의 다단계 다품목 공급사슬망 생산계획을 위한 휴리스틱 알고리즘)

  • Shin Hyun-Joon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.1
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    • pp.89-95
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    • 2006
  • Planning distributed manufacturing logistics is one of main issues in supply chain management. This paper proposes a hybrid heuristic approach for the Multi-Level, multi-item Capacitated Lot Sizing Problem (MLCLSP) in supply chain network. MLCLSP corresponds to a mixed integer programming (MIP) problem. With integer variable solutions determined by heuristic search, this MIP problem becomes linear program (LP). By repeatedly solving the relaxed MIP problems with a heuristic search method in a hybrid manner, this proposed approach allocates finite manufacturing resources fur each distributed facilities and generates feasible production plans. Meta heuristic search algorithm is presented to solve the MIP problems. The experimental test evaluates the computational performance under a variety of problem scenarios.

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Control System Design for Marine Vessel Satisfying Mixed H2/H Performance Condition (H2/H 설계사양을 만족하는 선박운동제어계 설계에 관한 연구)

  • Kang, Chang-Nam;Kim, Young-Bok
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.9
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    • pp.846-852
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    • 2013
  • In this paper, the authors propose a new approach to control problem of the marine vessels which are moored or controlled by actuators. The vessel control problem in the specified area is called a DPS (Dynamic Positioning System). The main objective of this paper is to obtain more useful control design method for DPS. In this problem, a complicate fact is control allocation which is a numerical method for distributing the control signal to the controlled system. For this, many results have been given and verified by other researchers using two individual processes. It means that the controller design and control allocation design process are carried out individually. In this paper, the authors give more sophisticated design solution on this issue. In which the controller design and control allocation problem are unified by a robust controller design problem. In other word, the stability of the closed-loop system, control performance and allocation problem are unified by an LMI (Linear Matrix Inequality) constraint based on $H_2/H_{\infty}$ mixed design framework. The usefulness of proposed approach is verified by simulation with a supply vessel model and found works well.

An NLP-based Mixed-method Approach to Explore the Impact of Gratifications and Emotions on the Acceptance of Amazon Go

  • Arghya Ray;Subhadeep Jana;Nripendra P. Rana
    • Asia pacific journal of information systems
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    • v.33 no.3
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    • pp.541-572
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    • 2023
  • Amazon Go is a cashierless convenience store concept, which is seen as a disruption in the grocery retail segment. Although Amazon Go has the ability to disrupt the retail segment, there are speculations on how Amazon Go will be perceived by users. Existing studies have not utilized user-generated content to understand the factors that affect customer behaviour in case of Amazon Go. Additionally, in case of phygital retail, studies have not attempted at understanding the effect of emotions and gratifications on user behaviour. To address the gap of exploring user perspectives based on their experience, we have examined the impact of gratifications and emotions on the acceptance of phygital retail using user-generated-content. A mixed-method approach has been utilized using only user-generated content. Utilizing topic-modelling based content analysis and emotion analysis on 30 articles related to Amazon Go, we found themes like, convenience, technology, experience, personalization, enjoyment and emotions like, bad, good, annoyance, success. In the empirical analysis, we have utilized 522 reviews about Amazon Go from the cognition and emotion theory stance, and found that hedonic gratifications have a positive impact on challenge emotions. We also found a significant impact of emotions on customer's favourite behaviour.

A Mixed-Method Approach to Explore the Motivations and Constraints of Kiosks Consumers

  • Taehyee Um;Hyunji Kim;Jumi RHee;Namho Chung
    • Asia pacific journal of information systems
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    • v.32 no.1
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    • pp.92-124
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    • 2022
  • Providing services using kiosks is actively carried out between suppliers and consumers. These service processes have recently begun to play a dominant role in transactions. However, previous self-service technology (SST) studies or kiosks have not fully reflected the changing environment surrounding these different technologies. To cover the updated business environments, we combined qualitative and quantitative research methods. Through qualitative research and a review of previous studies, the variables emphasized as motivations and constraints for kiosks use and those that can be newly illuminated were selected for this study. We then applied the variables to the research model to assess their influence. In terms of the motivations for using kiosks, the results suggest that perceived usefulness and compatibility as service quality, forced use, and perceived service providers' efficiency as provider polices, absorptive capacity, and habit as an individual characteristic and social influence as a subjective norm have a significant effect on the attitude toward kiosks. In terms of constraints, difficult to use and need for interaction predicts the attitude toward kiosks. Attitude toward kiosks, perceived behavioral control, and social influence are directly related to the intention to use kiosks. Lastly, intention to use kiosks plays a significant role as an antecedent of revisit intention. Using these empirical results, we propose both academic and practical implications for future kiosks use.

Combined Feature Set and Hybrid Feature Selection Method for Effective Document Classification (효율적인 문서 분류를 위한 혼합 특징 집합과 하이브리드 특징 선택 기법)

  • In, Joo-Ho;Kim, Jung-Ho;Chae, Soo-Hoan
    • Journal of Internet Computing and Services
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    • v.14 no.5
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    • pp.49-57
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    • 2013
  • A novel approach for the feature selection is proposed, which is the important preprocessing task of on-line document classification. In previous researches, the features based on information from their single population for feature selection task have been selected. In this paper, a mixed feature set is constructed by selecting features from multi-population as well as single population based on various information. The mixed feature set consists of two feature sets: the original feature set that is made up of words on documents and the transformed feature set that is made up of features generated by LSA. The hybrid feature selection method using both filter and wrapper method is used to obtain optimal features set from the mixed feature set. We performed classification experiments using the obtained optimal feature sets. As a result of the experiments, our expectation that our approach makes better performance of classification is verified, which is over 90% accuracy. In particular, it is confirmed that our approach has over 90% recall and precision that have a low deviation between categories.

Line Balancing for the Mixed Model Assembly Line Considering Processing Time and Physical Workloads (작업시간과 육체적인 작업부하를 고려한 혼합모델 조립공정의 라인밸런싱)

  • Moon, Sung-Min;Kwon, Keun-Seob;Choi, Gyung-Hyun
    • IE interfaces
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    • v.17 no.3
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    • pp.282-293
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    • 2004
  • Line Balancing is the problem to assign tasks to stations while satisfying some managerial viewpoints. Most researches about the Mixed-Model Line Balancing problems are focused on the minimizing the total processing time or the number of workstations. Independently, some research reports consider the balance issues of the physical workloads on the assembly line. In this paper, we are presenting a new mathematical model to accomplish the line balance considering both the processing time and the workloads at the same time. To this, end, we propose an zero-one integer program problem, and we use the Chebyshev Goal Programming approach as the solution method. Some computational test runs are performed to compare the pay-offs between the processing time and the workloads. And, the test results show us that the reliable balanced work schedules can be obtained through the proposed model.

Bayesian Hierarchical Mixed Effects Analysis of Time Non-Homogeneous Markov Chains (계층적 베이지안 혼합 효과 모델을 사용한 비동차 마코프 체인의 분석)

  • Sung, Minje
    • The Korean Journal of Applied Statistics
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    • v.27 no.2
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    • pp.263-275
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    • 2014
  • The present study used a hierarchical Bayesian approach was used to develop a mixed effect model to describe the transitional behavior of subjects in time nonhomogeneous Markov chains. The posterior distributions of model parameters were not in analytically tractable forms; subsequently, a Gibbs sampling method was used to draw samples from full conditional posterior distributions. The proposed model was implemented with real data.