• Journal of the Korean Mathematical Society
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• v.45 no.6
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• pp.1725-1740
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• 2008

In this paper, we introduce a fixed point index of weakly inward 1-set-contraction mappings. With the aid of the new index, we obtain some new fixed point theorems, nonzero fixed point theorems and multiple positive fixed points for this class of mappings. As an application of nonzero fixed point theorems, we discuss an eigenvalue problem.

• Journal of the Chungcheong Mathematical Society
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• v.26 no.1
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• pp.1-16
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• 2013

The aim of this paper is to establish a new fixed point theorem for a set-valued mapping defined on a metric space satisfying a weak contractive type condition and to establish a new common fixed point theorem for a pair of set-valued mappings defined on a metric space satisfying a weak contractive type inequality. And we give periodic point theorems for single-valued mappings defined on a metric space satisfying weak contractive type conditions.

• Kyungpook Mathematical Journal
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• v.56 no.3
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• pp.807-817
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• 2016

The aim of this paper is to introduce the notion of ${\epsilon}$-compatible maps and obtain some common fixed point theorems. Also, our results generalize some well known fixed point theorems.

• Bulletin of the Korean Mathematical Society
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• v.50 no.3
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• pp.993-1005
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• 2013

In this paper, to include more generalized cases, the authors present a modified concept for the tripled and quadruple fixed point of the mixed monotone mappings. Also, they investigate the existence and uniqueness of fixed point of the ordered monotone operator with the Matkowski contractive conditions in the partial ordered metric spaces. As the direct consequences, the existence of coupled fixed point, tripled fixed point and quadruple fixed point are explored at the common framework and some previous results in [T. G. Bhaskar and V. Lakshmikan-tham, Fixed point theory in partially ordered metric spaces and applications, Nonlinear Anal. 65 (2006), 1379-1393; V. Berinde and M. Borcut, Tripled fixed point theorems for contractive type mappings in partially ordered metric spaces, Nonlinear Anal. 74 (2011), no. 15, 4889-4897; E. Karapinar and N. V. Luong, Quadruple fixed point theorems for nonlinear contractions, Computers and Mathematics with Applications (2012), doi:10.1016/j.camwa.2012.02061] are improved. Finally, some fixed point theorems are proved.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1256-1258
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• 2003

The solar cells should be operated at the maximum power point because its output characteristics are greatly fluctuate on the variations of insolation, temperature and loads. To obtain maximum power from solar cell, photovoltaic system cell power system usually requires maximum power point tracking controller. This paper propose Maximum power point tracking method using zero slope of differential value of maximum power. The power compare method traces to maximum power point rapidly but oscillate on the maximum power point largely, when quantity insolation variation is big. The power compare method is traces to maximum power point slowly but oscillate maximum point on the maximum power point smally, when quantity insolation variation is small. To solve two problem of the power compare method, designed zero slope of differential value of maximum power.

• Progress in Medical Physics
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• v.28 no.3
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• pp.111-121
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• 2017

Verification of dose distribution is an essential part of ensuring the treatment planning system's (TPS) calculated dose will achieve the desired outcome in radiation therapy. Each measurement have uncertainty associated with it. It is desirable to reduce the measurement uncertainty. A best approach is to reduce the uncertainty associated with each step of the process to keep the total uncertainty under acceptable limits. Point dose patient specific quality assurance (QA) is recommended by American Association of Medical Physicists (AAPM) and European Society for Radiotherapy and Oncology (ESTRO) for all the complex radiation therapy treatment techniques. Relative and absolute point dose measurement methods are used to verify the TPS computed dose. Relative and absolute point dose measurement techniques have a number of steps to measure the point dose which includes chamber cross calibration, electrometer reading, chamber calibration coefficient, beam quality correction factor, reference conditions, influences quantities, machine stability, nominal calibration factor (for relative method) and absolute dose calibration of machine. Keeping these parameters in mind, the estimated relative percentage uncertainty associated with the absolute point dose measurement is 2.1% (k=1). On the other hand, the relative percentage uncertainty associated with the relative point dose verification method is estimated to 1.0% (k=1). To compare both point dose measurement methods, 13 head and neck (H&N) IMRT patients were selected. A point dose for each patient was measured with both methods. The average percentage difference between TPS computed dose and measured absolute relative point dose was 1.4% and 1% respectively. The results of this comparative study show that while choosing the relative or absolute point dose measurement technique, both techniques can produce similar results for H&N IMRT treatment plans. There is no statistically significant difference between both point dose verification methods based upon the t-test for comparing two means.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.448-454
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• 2022

An intralaboratory comparison of the realization of the triple-point temperature of mercury, which is defined as -38.8344℃ on the international temperature scale of 1990 (ITS-90), was conducted at the Korea Research Institute of Standards and Science (KRISS), the national metrology institute of Korea. To this end, four triple-point-of-mercury cells were compared using the resistance ratio measurement of a standard platinum resistance thermometer to validate the calibration results obtained using the triple-point-of-mercury cells at KRISS. The triple-point temperatures of all the four cells, one of which is designated as the national standard cell, were within 0.3 mK of the national standard. Based on 13 experiments on the four triple-point-of-mercury cells, the uncertainty in the comparison of the triple-point-of-mercury cells was 0.08 mK, and the uncertainty in the realization of the triple-point temperature of mercury was 0.19 mK. The results of the intralaboratory comparison validated that utilizing any of the four triple-point-of-mercury cells would result in the realization of a temperature within 0.3 mK of the average value determined by two key international comparisons for the realization of -38.3844℃ following the ITS-90.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1196-1198
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• 2015

최근 모바일 기기의 발전으로 사용자의 위치를 수집하고 분석하는 방법들이 연구되고 있다. 이러한 방법들 중 하나인 궤적 데이터 마이닝은 사용자의 궤적을 바탕으로 의미 있는 정보를 추출하기 위해 사용된다. 궤적 데이터 마이닝을 수행하기 위해서는 사용자의 GPS로그를 분석하여 Stay Point를 추출하는 과정이 선행되어야 한다. 기존의 Stay Point 추출 방법은 실내와 실외의 Stay Point를 구분하지 못한다. 본 논문에서는 기존의 Stay Point 알고리즘을 보완하기 위해 GPS 데이터 분포를 고려하여 실내에서 머무른 지점만을 추출하는 Stay Point 알고리즘을 제안한다.

• Communications for Statistical Applications and Methods
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• v.12 no.2
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• pp.349-357
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• 2005

We suggest a functional technique with loess smoothing for estimating the change-point when there is one change-point in the mean model. The proposed change-point estimator is consistent. Simulation study shows a good performance of the proposed change-point estimator in comparison with other parametric or nonparametric change-point estimators.

• Communications of the Korean Mathematical Society
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• v.20 no.2
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• pp.299-310
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• 2005

This paper presents new random fixed point theorems for $U_c^k$ maps and new random Leray-Schauder alternatives for $U_c^k$ type maps. Our arguments rely on recent deterministic fixed point theorems and on a result on hemicompact maps in the literature.