• 제목/요약/키워드: Margin generating algorithm

검색결과 5건 처리시간 0.02초

지역별 예비력 제약과 융통전력을 고려한 발전기 예방정비 계획 해법 (Generating Unit Maintenance Scheduling Considering Regional Reserve Constraints and Transfer Capability Using Hybrid PSO Algorithm)

  • 박영수;박준호;김진호
    • 전기학회논문지
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    • 제56권11호
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    • pp.1892-1902
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    • 2007
  • This paper presents a new generating unit maintenance scheduling algorithm considering regional reserve margin and transfer capability. Existing researches focused on reliability of the overall power systems have some problems that adequate reliability criteria cannot be guaranteed in supply shortage regions. Therefore specific constraints which can treat regional reserve ratio have to be added to conventional approaches. The objective function considered in this paper is the variance (second-order momentum) of operating reserve margin to levelize reliability during a planning horizon. This paper focuses on significances of considering regional reliability criteria and an advanced hybrid optimization method based on PSO algorithm. The proposed method has been applied to IEEE reliability test system(1996) with 32-generators and a real-world large scale power system with 291 generators. The results are compared with those of the classical central maintenance scheduling approaches and conventional PSO algorithm to verify the effectiveness of the algorithm proposed in this paper.

이진 PSO 알고리즘의 발전기 보수계획문제 적용 (An Application of a Binary PSO Algorithm to the Generator Maintenance Scheduling Problem)

  • 박영수;김진호
    • 전기학회논문지
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    • 제56권8호
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    • pp.1382-1389
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    • 2007
  • This paper presents a new approach for solving the problem of maintenance scheduling of generating units using a binary particle swarm optimization (BPSO). In this paper, we find the optimal solution of the maintenance scheduling of generating units within a specific time horizon using a binary particle swarm optimization algorithm, which is the discrete version of a conventional particle swarm optimization. It is shown that the BPSO method proposed in this paper is effective in obtaining feasible solutions in the maintenance scheduling of generating unit. IEEE reliability test systems(1996) including 32-generators are selected as a sample system for the application of the proposed algorithm. From the result, we can conclude that the BPSO can find the optimal solution of the maintenance scheduling of the generating unit with the desirable degree of accuracy and computation time, compared to other heuristic search algorithm such as genetic algorithms. It is also envisaged that BPSO can be easily implemented for similar optimizations and scheduling problems in power system problems to obtain better solutions and improve convergence performance.

인터넷 경매를 위한 지능형 에이전트 기반 마진 푸쉬 멀티에이전트 시스템 설계 및 구현 (Design and Implementation of Intelligent Agent based Margin Push Multi-agent System for Internet Auction)

  • 이근왕;김정재;이종희;오해석
    • 정보처리학회논문지D
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    • 제9D권1호
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    • pp.167-172
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    • 2002
  • 최근 전자상거래에서 지능적인 소프트웨어 에이전트를 이용하여 사용자에게 더욱 능률적이고 효과적인 경매시스템으로 발전시키고자 하는 연구 및 개발이 주목을 받고 있다. 단순한 게시판 형식의 인터넷 경매 시스템에 인공지능 에이전트를 도입하여 해당 경매 상품에 대해 판매자에게 적정한 경매 시기와 초기값을 계산하고 예측하여 최대한의 이익을 남길 수 있도록 해주는 에이전트 시스템에 대한 연구가 본 논문의 목적이다. 상품을 인터넷 경매에 올리는 판매자가 판매하고자 하는 경매 상품에 대한 정보를 인터넷 경매 시스템의 에이전트에게 메일로 보내면 에이전트는 해당 상품과 유사한 상품에 대하여 필터링하여 이미 학습되고 있는 유사 상품에 대한 정보 즉, 데이터베이스에 저장되어 있는 경매상품에 대한 입찰 히스토리로부터 경매시간, 경매방법, 낙찰가격 등을 계산한다. 본 논문은 이를 통하여 해당 상품에 대하여 판매자가 어느 시기에 얼마의 초기 가격으로 경매를 시작하면 최대한의 이익을 남길 수 있는지에 대한 정보를 메일로 푸쉬하여 주는 시스템을 제안한다.

CRYSTALS-Dilithium 대상 비프로파일링 기반 전력 분석 공격 성능 개선 연구 (A Study on Performance Improvement of Non-Profiling Based Power Analysis Attack against CRYSTALS-Dilithium)

  • 장세창;이민종;강효주;하재철
    • 정보보호학회논문지
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    • 제33권1호
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    • pp.33-43
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    • 2023
  • 최근 미국의 국립표준기술연구소(NIST: National Institute of Standards and Technology)는 양자 내성 암호(PQC: Post-Quantum Cryptography, 이하 PQC) 표준화 사업을 진행하여 4개의 표준 암호 알고리즘을 발표하였다. 본 논문에서는 전자서명 분야에서 표준화가 확정된 CRYSTALS-Dilithium 알고리즘을 이용하여 서명을 생성하는 과정에서 동작하는 다항식 계수별 곱셈 알고리즘을 대상으로 비프로파일링 기반 전력 분석 공격인 CPA(Correlation Power Analysis)나 DDLA(Differential Deep Learning Analysis) 공격에 의해 개인 키가 노출될 수 있음을 실험을 통해 증명한다. ARM-Cortex-M4 코어에 알고리즘을 탑재하여 실험결과, CPA 공격과 DDLA 공격에서 개인 키 계수를 복구할 수 있음을 확인하였다. 특히 DDLA 공격에서 StandardScaler 전처리 및 연속 웨이블릿 변환을 적용한 전력 파형을 이용하였을 때 공격에 필요한 최소 전력 파형의 개수가 줄어들고 NMM(Normalized Maximum Margin) 값이 약 3배 증가하여 공격 성능이 크게 향상됨을 확인하였다.

다분류 SVM을 이용한 DEA기반 벤처기업 효율성등급 예측모형 (The Prediction of DEA based Efficiency Rating for Venture Business Using Multi-class SVM)

  • 박지영;홍태호
    • Asia pacific journal of information systems
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    • 제19권2호
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    • pp.139-155
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    • 2009
  • For the last few decades, many studies have tried to explore and unveil venture companies' success factors and unique features in order to identify the sources of such companies' competitive advantages over their rivals. Such venture companies have shown tendency to give high returns for investors generally making the best use of information technology. For this reason, many venture companies are keen on attracting avid investors' attention. Investors generally make their investment decisions by carefully examining the evaluation criteria of the alternatives. To them, credit rating information provided by international rating agencies, such as Standard and Poor's, Moody's and Fitch is crucial source as to such pivotal concerns as companies stability, growth, and risk status. But these types of information are generated only for the companies issuing corporate bonds, not venture companies. Therefore, this study proposes a method for evaluating venture businesses by presenting our recent empirical results using financial data of Korean venture companies listed on KOSDAQ in Korea exchange. In addition, this paper used multi-class SVM for the prediction of DEA-based efficiency rating for venture businesses, which was derived from our proposed method. Our approach sheds light on ways to locate efficient companies generating high level of profits. Above all, in determining effective ways to evaluate a venture firm's efficiency, it is important to understand the major contributing factors of such efficiency. Therefore, this paper is constructed on the basis of following two ideas to classify which companies are more efficient venture companies: i) making DEA based multi-class rating for sample companies and ii) developing multi-class SVM-based efficiency prediction model for classifying all companies. First, the Data Envelopment Analysis(DEA) is a non-parametric multiple input-output efficiency technique that measures the relative efficiency of decision making units(DMUs) using a linear programming based model. It is non-parametric because it requires no assumption on the shape or parameters of the underlying production function. DEA has been already widely applied for evaluating the relative efficiency of DMUs. Recently, a number of DEA based studies have evaluated the efficiency of various types of companies, such as internet companies and venture companies. It has been also applied to corporate credit ratings. In this study we utilized DEA for sorting venture companies by efficiency based ratings. The Support Vector Machine(SVM), on the other hand, is a popular technique for solving data classification problems. In this paper, we employed SVM to classify the efficiency ratings in IT venture companies according to the results of DEA. The SVM method was first developed by Vapnik (1995). As one of many machine learning techniques, SVM is based on a statistical theory. Thus far, the method has shown good performances especially in generalizing capacity in classification tasks, resulting in numerous applications in many areas of business, SVM is basically the algorithm that finds the maximum margin hyperplane, which is the maximum separation between classes. According to this method, support vectors are the closest to the maximum margin hyperplane. If it is impossible to classify, we can use the kernel function. In the case of nonlinear class boundaries, we can transform the inputs into a high-dimensional feature space, This is the original input space and is mapped into a high-dimensional dot-product space. Many studies applied SVM to the prediction of bankruptcy, the forecast a financial time series, and the problem of estimating credit rating, In this study we employed SVM for developing data mining-based efficiency prediction model. We used the Gaussian radial function as a kernel function of SVM. In multi-class SVM, we adopted one-against-one approach between binary classification method and two all-together methods, proposed by Weston and Watkins(1999) and Crammer and Singer(2000), respectively. In this research, we used corporate information of 154 companies listed on KOSDAQ market in Korea exchange. We obtained companies' financial information of 2005 from the KIS(Korea Information Service, Inc.). Using this data, we made multi-class rating with DEA efficiency and built multi-class prediction model based data mining. Among three manners of multi-classification, the hit ratio of the Weston and Watkins method is the best in the test data set. In multi classification problems as efficiency ratings of venture business, it is very useful for investors to know the class with errors, one class difference, when it is difficult to find out the accurate class in the actual market. So we presented accuracy results within 1-class errors, and the Weston and Watkins method showed 85.7% accuracy in our test samples. We conclude that the DEA based multi-class approach in venture business generates more information than the binary classification problem, notwithstanding its efficiency level. We believe this model can help investors in decision making as it provides a reliably tool to evaluate venture companies in the financial domain. For the future research, we perceive the need to enhance such areas as the variable selection process, the parameter selection of kernel function, the generalization, and the sample size of multi-class.