• 제목/요약/키워드: upper/lower bounds

검색결과 254건 처리시간 0.024초

신호의 도착방향을 추정하는 새로운 Null-Spectrum (A New Null-Spectrum for Direction of Arrival Estimation)

  • 최진호;김상엽;김선용;박성일;손재철;송익호;윤진선
    • 한국통신학회:학술대회논문집
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    • 한국통신학회 1991년도 추계종합학술발표회논문집
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    • pp.123-126
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    • 1991
  • A generalization of null-spectrum for use in the estimation of directions of arrival of signal sources is considered in this paper. The upper and lower bounds of the generalized null-spectrum, the maximum and minimum null-spectra, are also derived. We observed that the maximum null-spectrum has higher resolution capability than other null-spectra including the two well-known null-spectra, the multiple signal classification null-spectrum and the Min-Norm null-spectrum.

On Estimating Burr Type XII Parameter Based on General Type II Progressive Censoring

  • Kim Chan-Soo
    • Communications for Statistical Applications and Methods
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    • 제13권1호
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    • pp.89-99
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    • 2006
  • This article deals with the problem of estimating parameters of Burr Type XII distribution, on the basis of a general progressive Type II censored sample using Bayesian viewpoints. The maximum likelihood estimator does not admit closed form but explicit sharp lower and upper bounds are provided. Assuming squared error loss and linex loss functions, Bayes estimators of the parameter k, the reliability function, and the failure rate function are obtained in closed form. Finally, a simulation study is also included.

흐름량을 고려한 네트워크 생존도 계산방법에 관한 연구 (An Algorithm for Calculating Flow-based Network Survivability)

  • 명영수;김현준
    • 한국경영과학회지
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    • 제26권3호
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    • pp.65-77
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    • 2001
  • Survivability of a network is one of the most important issues in designing present-day communication networks. the k-edge survivability of a given network is defined as the percentage of total traffic surviving the worst case failure of k edges. Although several researches calculated k-edge survivability on small networks by enumeration, prior research has considered how to calculate k-edge survivability on large networks. In this paper, we develop an efficient procedure to obtain lower and upper bounds on the k-edge survivability of a network.

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INVERSE MINIMUM FLOW PROBLEM

  • Ciurea, Eleonor;Deaconu, Adrian
    • Journal of applied mathematics & informatics
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    • 제23권1_2호
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    • pp.193-203
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    • 2007
  • In this paper we consider the inverse minimum flow (ImF) problem, where lower and upper bounds for the flow must be changed as little as possible so that a given feasible flow becomes a minimum flow. A linear time and space method to decide if the problem has solution is presented. Strongly and weakly polynomial algorithms for solving the ImF problem are proposed. Some particular cases are studied and a numerical example is given.

Forbidden Detour Number on Virtual Knot

  • Yoshiike, Shun;Ichihara, Kazuhiro
    • Kyungpook Mathematical Journal
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    • 제61권1호
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    • pp.205-212
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    • 2021
  • We show that the forbidden detour move, essentially introduced by Kanenobu and Nelson, is an unknotting operation for virtual knots. Then we define the forbidden detour number of a virtual knot to be the minimal number of forbidden detour moves necessary to transform a diagram of the virtual knot into the trivial knot diagram. Some upper and lower bounds on the forbidden detour number are given in terms of the minimal number of real crossings or the coefficients of the affine index polynomial of the virtual knot.

SHARP ESTIMATES ON THE THIRD ORDER HERMITIAN-TOEPLITZ DETERMINANT FOR SAKAGUCHI CLASSES

  • Kumar, Sushil;Kumar, Virendra
    • 대한수학회논문집
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    • 제37권4호
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    • pp.1041-1053
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    • 2022
  • In this paper, sharp lower and upper bounds on the third order Hermitian-Toeplitz determinant for the classes of Sakaguchi functions and some of its subclasses related to right-half of lemniscate of Bernoulli, reverse lemniscate of Bernoulli and exponential functions are investigated.

전자패키지용 EMC의 기계적 성질 및 패키지내의 열응력해석 (A Study on the Mechanical Properties of EMC and Thermal Stress Anlaysis in Electronic Packagings)

  • 신동길;이정주
    • 대한기계학회논문집A
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    • 제20권11호
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    • pp.3538-3548
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    • 1996
  • In this study, as a part of basic study for developing the simulation program for the assemssment of reliability of electronic EMC packaging which covers from EMC mixing step to thermal analysis, comparison between a measured and predicted values of material properties of EMC and finitde element analysis of thermal stress are performed. For the experimental testing specimens of fifty, sixty hive and eighty percent filler($13\mu m$, spherical silica) weight fraction are fabricated using tranfer molding. Coefficient of thermal expansion, elastic modulus and thermla conductivity are measured using these specimens and then these measured values are compared with the predicted values by various equations ( such as dilute suspension method. self consistent method, generalized self consistent method, Hashin-Shtrikman's bounds. Shapery's bounds, Nielsen's method and others). Measured values are distributed within the upper and lower bounds of equations. Measured elastic modulus and coefficient of thermal expansion approaches closely the perdicted values with self consisten mehtod and upper bound of Shaperys equation respectively. However small differences of thermal conductivity between the different filler volume fraction are obserbed. FEM analysis indicates that firstly stress is concentrated at the corner section of EMC and secondly EMC with eighty percent filler weight fraction shows less thermal stress when package is cooling down and relatively high thermal stress when package is heating up.