• 대한수학회보
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• 제54권3호
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• pp.1081-1094
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• 2017

For a poset $P=(X,{\leq}_P)$, the linear discrepancy of P is the minimum value of maximal differences of all incomparable elements for all possible labelings. In this paper, we find a lower bound and an upper bound of the linear discrepancy of a product of two posets. In order to give a lower bound, we use the known result, $ld({\mathbf{m}}{\times}{\mathbf{n}})={\lceil}{\frac{mn}{2}}{\rceil}-2$. Next, we use Dilworth's chain decomposition to obtain an upper bound of the linear discrepancy of a product of a poset and a chain. Finally, we give an example touching this upper bound.

• 지역사회간호학회지
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• 제22권2호
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• pp.192-203
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• 2011

Purpose: This study was conducted to develop and assess the feasibility of an upper extremity exercise program based on Patterned Sensory Enhancement (PSE) for home-bound stroke patients by measuring the level of upper extremity function, depression, and interpersonal relationship. Methods: The experiments were performed on stroke patients at three different rehabilitation centers in Incheon City. Twenty patients participated in the experimental group or in the control group. The program was executed three times a week for 6 weeks. Data were collected from August to October, 2006. Manual Function Test was used to quantify and evaluate upper extremity function. The depression level and the effectiveness of interpersonal relationship were quantified and measured using CES-D and Relationship Change Scale, respectively. Results: The effectiveness of upper extremity function of stroke patients who participated in the PSE upper extremity exercise program was higher than that of non-participating patients. The depression level decreased and interpersonal relationship improved in the stroke patients who participated in this program compared to those who did not. Conclusion: These findings prove that the PSE upper extremity exercise program for home-bound stroke patients was an effective strategy for enhancing upper extremity function, decreasing the depression level, and improving interpersonal relationships.

• 한국정밀공학회지
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• 제8권3호
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• pp.93-104
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• 1991

Limit analysis is based on the duality theorem which equates the least upper bound to the greatest lower bound. In this study, limit analysis of axisymmetric forming problem with workhardening materials is formulated by minimizing the upper bound functional and finite element program is developed for forward estrusion. Limit loads, velocity and flow line fields are directly obtained under various process conditions and deformation characteristics such as strains, strain rates and grid distortion are obtained from the optimum velocity components by numerical calculation. The experimental observation was carried out for extrusion and compared with computed results. The good agreement between theoretical and experimental results is shown that the developed programming is very effective for the analysis of axisymmetric extrusion.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1780-1783
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• 2002

A problem of signal transmitted and received in OFDM systems is considered. In particular, an efficient solution to the problem of blind channel estimation based on Maximum Likelihood (ML) principle has been investigated. The paper proposes a new upper-bound cost, used in conjunction with a standard branch and bound integer programming technique for solving the ML problem. The tighter upper-bound cost exploits a finite-alphabet property of the transmitted signal. The proposed upper-bound cost was found to greatly speed up the ML algorithm, thus reducing computational complexity. Experimental results and discussion are included.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.372-377
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• 1993

In this paper, we investigate a set-membership identification approach to the quantification of an upper bound of model uncertainty in frequency domain, which is required in the H$_{\infty}$ robust control system design. First we formulate this problem as a set-membership identification of a nominal model error in the presence f unknown noise input with unknown bound, while the ordinary set-membership approaches assume that an upper bound of the uncertain input is known. For this purpose, the proposed algorithm includes the estimation of the bound of the uncertain input. thus the proposed method can obtain the hard bound of the model error in frequency domain as well as a parametric lower-order nominal model. Finally numerical simulation results are shown to confirm the validity of the presented algorithm..

• East Asian mathematical journal
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• 제36권1호
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• pp.91-99
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• 2020

This paper obtains an explicit expression for a debtor's consumption, porfolio and time for filing for bankruptcy when the debtor is subject to upper bound on consumption rate. The utility of consumption is CRRA type and the dynamic programming principle is applied.

• East Asian mathematical journal
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• 제26권3호
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• pp.423-427
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• 2010

In this paper, we give an upper bound for dominations of Steinhaus graphs, and the domination numbers of the bipartite Steinhaus graphs. Also, we give an upper bound for Nordhaus-Gaddum type result for the bipartite Steinhaus graphs.

• Journal of Communications and Networks
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• 제6권4호
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• pp.352-361
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• 2004

In this paper, we study how to achieve the maximum capacity under delay constraints for large mobile wireless networks. We develop a systematic methodology for studying this problem in the asymptotic region when the number of nodes n in the network is large. We first identify a number of key parameters for a large class of scheduling schemes, and investigate the inherent tradeoffs among the capacity, the delay, and these scheduling parameters. Based on these inherent tradeoffs, we are able to compute the upper bound on the maximum per-node capacity of a large mobile wireless network under given delay constraints. Further, in the process of proving the upper bound, we are able to identify the optimal values of the key scheduling parameters. Knowing these optimal values, we can then develop scheduling schemes that achieve the upper bound up to some logarithmic factor, which suggests that our upper bound is fairly tight. We have applied this methodology to both the i.i.d. mobility model and the random way-point mobility model. In both cases, our methodology allows us to develop new scheduling schemes that can achieve larger capacity than previous proposals under the same delay constraints. In particular, for the i.i.d. mobility model, our scheme can achieve (n-1/3/log3/2 n) per-node capacity with constant delay. This demonstrates that, under the i.i.d. mobility model, mobility increases the capacity even with constant delays. Our methodology can also be extended to incorporate additional scheduling constraints.

• 대한토목학회논문집
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• 제12권1호
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• pp.187-196
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• 1992

본 연구에서는 편심 하중을 받는 기초의 지지력을 극한해석 상계법을 이용하여 산정하였다. 편심 하중이 작용하는 기초의 지지력을 산정하는 기존의 해석방법으로는 극한평형법을 이용한 Meyerhof 방법과 Saran 방법 등이 있으나, 극한해석법을 이용하여 해석하는 경우는 없다. 이에 본 연구에서는 극한해석 상계법을 이용하여 편심하중이 작용하는 기초의 지지력을 산정하였다. 극한해석 상계법으로 해석하는 경우, 적용하는 파괴메카니즘에 따라 그 결과가 달라지므로, 본 연구에서는 기존의 파괴메카니즘을 속도장 조건에 맞게 변형시킨 후, 극한해석 상계법을 적용하여 그 결과들을 상호 비교하였다. 그리고, 편심하중을 받는 기초 구조물의 지지력에 영향을 미치는 요소들을 연구하기 위하여 흙의 내부마찰각, 기초 바닥면의 마찰각, 편심량, 그리고 상재하중 등을 변화시켜 각 요소들이 기초의 지지력에 미치는 영향을 연구하였다.

• 한국통신학회논문지
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• 제32권5B호
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• pp.257-269
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• 2007

네트워크 계층의 MANET 라우팅 프로토콜이 개발될 때 가장 주요한 관심사는 라우팅 오버헤드 (Overhead)의 축소이다. 본 논문에서는 MANET 에서 단일 노드가 자동 네크워킹 프로토콜에 의해 IP 주소를 획득할 때의 라우팅 오버헤드 (메시지 복잡도)를 정량적으로 분석하는 수학적 방법을 제안한다. MANET에서 자동 네크워킹 프로토콜은 IP 주소 할당시 IP 주소 충돌회피에 사용된다. 메시지 복잡도는 Upper Bound에 의해 수학적으로 정량화 되고, 실제 주소 할당을 컴퓨터 시뮬레이터로 구현하여, 제안된 Upper Bound와 시뮬레이션 결과를 비교, 분석한다. 메시지 복잡도의 Upper Bound는 Worst Case 시나리오 분석에 의해 유도된다.