• 제목/요약/키워드: perfect number

검색결과 274건 처리시간 0.03초

Cryptanalysis and improvement of a Multi-server Authentication protocol by Lu et al.

  • Irshad, Azeem;Sher, Muhammad;Alzahrani, Bander A.;Albeshri, Aiiad;Chaudhry, Shehzad Ashraf;Kumari, Saru
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제12권1호
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    • pp.523-549
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    • 2018
  • The increasing number of subscribers and demand of multiplicity of services has turned Multi-Server Authentication (MSA) into an integral part of remote authentication paradigm. MSA not only offers an efficient mode to register the users by engaging a trusted third party (Registration Centre), but also a cost-effective architecture for service procurement, onwards. Recently, Lu et al.'s scheme demonstrated that Mishra et al.'s scheme is unguarded to perfect forward secrecy compromise, server masquerading, and forgery attacks, and presented a better scheme. However, we discovered that Lu et al.'s scheme is still susceptible to malicious insider attack and non-compliant to perfect forward secrecy. This study presents a critical review on Lu et al.'s scheme and then proposes a secure multi-server authentication scheme. The security properties of contributed work are validated with automated Proverif tool and proved under formal security analysis.

Assessing Bank Competition in Nepal Using Panzar-Rosse Model

  • BUDHATHOKI, Prem Bahadur;RAI, Chandra Kumar;RAI, Arjun
    • The Journal of Asian Finance, Economics and Business
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    • 제7권11호
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    • pp.759-768
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    • 2020
  • The purpose of this study is to assess the state of competition in Nepalese banking over the period from 2010 to 2019. This study employs panel data and a non-structural Panzar-Rosse model to measure the degree of competition in the Nepalese banking industry. The first reduced-form equation is applied to gauge competition, and the second model is used to test the long-run equilibrium in the banking market. The finding reveals that the Nepalese banking market is equilibrium in the long-run. It implies that the factor prices do not affect ROA in the long-run. The result of the H-statistic shows that the Nepalese banking system is operating under the state of perfect competition and is shifted from monopolistic competition to perfect competition. The reduced-form model reveals that the interest income is positive and significantly affected by factor prices. Similarly, the macroeconomic variable GDP growth is positively related to interest income. On the contrary, the bank's specific factors risk and the number of bank branches are inversely associated with the regressand. The outcomes of the study may be advantageous to the policymakers, especially to Nepal Rastra Bank to implement monetary policy and M&A policy for the stability and growth of the financial system of Nepal.

Classification of Plants into Families based on Leaf Texture

  • TREY, Zacrada Francoise;GOORE, Bi Tra;BAGUI, K. Olivier;TIEBRE, Marie Solange
    • International Journal of Computer Science & Network Security
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    • 제21권2호
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    • pp.205-211
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    • 2021
  • Plants are important for humanity. They intervene in several areas of human life: medicine, nutrition, cosmetics, decoration, etc. The large number of varieties of these plants requires an efficient solution to identify them for proper use. The ease of recognition of these plants undoubtedly depends on the classification of these species into family; however, finding the relevant characteristics to achieve better automatic classification is still a huge challenge for researchers in the field. In this paper, we have developed a new automatic plant classification technique based on artificial neural networks. Our model uses leaf texture characteristics as parameters for plant family identification. The results of our model gave a perfect classification of three plant families of the Ivorian flora, with a determination coefficient (R2) of 0.99; an error rate (RMSE) of 1.348e-14, a sensitivity of 84.85%, a specificity of 100%, a precision of 100% and an accuracy (Accuracy) of 100%. The same technique was applied on Flavia: the international basis of plants and showed a perfect identification regression (R2) of 0.98, an error rate (RMSE) of 1.136e-14, a sensitivity of 84.85%, a specificity of 100%, a precision of 100% and a trueness (Accuracy) of 100%. These results show that our technique is efficient and can guide the botanist to establish a model for many plants to avoid identification problems.

이진 알고리즘을 이용한 변형 시리얼테스트 설계에 관한 연구 (Design variation serial test using binary algorithm)

  • 최진석;이성주
    • 한국지능시스템학회논문지
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    • 제20권1호
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    • pp.76-80
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    • 2010
  • 급변하는 정보의 홍수 속에서 정보의 보안과 이를 가공하고 전송하는 것이 중요한 과제로 떠오르고 있다. 초기 정보보호이론과 암호화 전송단계에서는 간단한 치환과 수학적 계산 알고리즘을 적용한 암 복호화 과정을 이용하였다. 완벽한 정보보호는 One-time pad를 이용하는 것이나 이를 적용하기에는 하드웨어와 금전적 손실이 너무 크기에 실난수가 아닌 난수성을 만족하는 의사난수를 사용하고 있다. 본고에서 제안하는 변형 시리얼 테스트는 의사난수성을 입증하는 테스트 중 시리얼테스트에서 변형된 것으로 연산속도와 효율성 면에서 보다 더 강력한 난수성임을 입증하고 있다.

분포통계모델에 의한 가교폴리에틸렌 절연체의 부분방전 패턴해석 (Analysis of the Partial Discharge Pattern in XLPE Insulators using Distribution Statistical Models)

  • 김탁용;박희두;조경순;박하용;홍진웅
    • 한국전기전자재료학회논문지
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    • 제19권10호
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    • pp.947-952
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    • 2006
  • It has been confirmed that the inner defect of insulator and the perfect diagnosis for aging are closely related to safe electric power transmission system and that the detection of accident and diagnosis technique turn out to be very important issues. But perfect diagnosis is difficult because discharge pattern is irregular. Thus, we investigated discharge pattern using the new distribution statistical models with cross-inked polyethylene(XLPE) specimens. Voltage was applied to power frequency by step method, and calibration of discharge was set to 50 pC. After the voltage was applied, it measured the discharge occurring during 10s. We investigated discharge pattern using the K-means analysis and Weibull function. We also investigated variation of centroid and shape parameter due to variation of voltage. As a result of analyzing K-means, it was confirmed that cluster including many object numbers was formed by the presence of void. And result of Weibull distribution, it was confirmed that shape parameter of discharge varied from 1.28 to 1.62 in no void specimens, and that shape parameter of discharge number varied from 1.28 to 1.62. In the void, shape parameter of discharge varied from 5.66 to 6.43, and shape parameter of discharge number varied from 5.05 to 5.08.

두 개의 원형 실린더 주위의 열전달 (Heat transfer on two nearby circular cylinders)

  • 한태헌;양경수;윤동혁;이경준
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.2890-2895
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    • 2007
  • Heat transfer on two identical nearby circular cylinders immersed in the uniform cross flow at Re = 100 and Pr = 7.0 was numerically studied. We consider all possible arrangements of the two circular cylinders in terms of the distance between the two cylinders and the inclination angle with respect to the direction of the main flow. It turns out that significant changes in the characteristics of heat transfer are noticed depending on how the two circular cylinders are positioned, resulting in quantitative changes of heat transfer coefficients on both cylinders. Collecting all the numerical results obtained, we propose a contour diagram for averaged Nusselt number for each of the two cylinders. The perfect geometrical symmetry implied in the flow configuration allows one to use those diagrams to estimate heat transfer rates on two identical circular cylinders arbitrarily positioned in physical space with respect to the main flow direction.

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두 개의 원형 실린더 주위의 열전달 (HEAT TRANSFER ON TWO NEARBY CIRCULAR CYLINDERS)

  • 한태헌;양경수;윤동혁;이경준
    • 한국전산유체공학회지
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    • 제13권2호
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    • pp.42-47
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    • 2008
  • Heat transfer on two identical nearby circular cylinders immersed in the uniform cross flow at Re=120 and Pr=0.7 was numerically studied. We consider all possible types of arrangements of the two circular cylinders in terms of the distance between the two cylinders and the inclination angle with respect to the direction of the main flow. It turns out that significant changes in the characteristics of heat transfer are noticed depending on how the two circular cylinders are positioned, resulting in quantitative changes of heat transfer coefficients on both cylinders. Collecting all the numerical results obtained, we propose a contour diagram for averaged Nusselt number for each of the two cylinders. The perfect geometrical symmetry implied in the flow configuration allows one to use those diagrams to estimate heat transfer rates on two identical circular cylinders arbitrarily positioned in physical space with respect to the main flow direction.

Enhancing Association Rule Mining with a Profit Based Approach

  • Li Ming-Lai;Kim Heung-Num;Jung Jason J.;Jo Geun-Sik
    • 한국정보과학회:학술대회논문집
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    • 한국정보과학회 2005년도 가을 학술발표논문집 Vol.32 No.2 (1)
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    • pp.973-975
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    • 2005
  • With the continuous growth of e-commerce there is a huge amount of products information available online. Shop managers expect to apply information techniques to increase profit and perfect service. Hence many e-commerce systems use association rule mining to further refine their management. However previous association rule algorithms have two limitations. Firstly, they only use the number to weight item's essentiality and ignore essentiality of item profit. Secondly, they did not consider the relationship between number and profit of item when they do mining. We address a novel algorithm, profit-based association rule algorithm that uses profit-based technique to generate 1-itemsets and the multiple minimum supports mining technique to generate N-items large itemsets.

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폐-루프 다중안테나시스템에서 제한된 피드백을 이용한 시공간블록부호기술의 적용 (Unitary precoding space time block coding with limited feedback)

  • 김정미;오동진;김철성
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2005년도 추계종합학술대회
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    • pp.85-88
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    • 2005
  • Space-time code is a good solution to get transmit diversity. During the last years a number of space-time block codes have been proposed for use in multiple transmit antenna systems. This code, however, was presented only for the special case of the certain numbers of transmit antennas and the certain modulation schemes. and designed under the assumption that the transmitter has no knowledge about the channel. In this work, on the other hand, we consider the case when the transmitter has partial, but not perfect knowledge about the channel. This system can have full diversity for arbitrary number of the transmit antennas with a little bits of feedback.

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전방 십자 인대 재재건술 (Revision Anterior Cruciate Ligamnet Reconstruction)

  • 안진환;이상학
    • 대한관절경학회지
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    • 제9권2호
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    • pp.115-122
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    • 2005
  • 전방 십자 인대 재건술의 빈도가 증가함에 따라 재재건술의 빈도 또한 증가하고 있는 추세이다. 관절경의 발전과 수술 술기의 발달에도 불구하고 많은 환자들이 재건술 후 불 만족스러운 결과를 보여주고 있다. 이에 일차적 전방십자 인대 재건술의 실패의 원인과 재재건술의 수술 술기와 환자에 대한 접근에 대하여 알아보고자 한다.

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