• Korean Journal of Mathematics
• /
• 제17권4호
• /
• pp.473-480
• /
• 2009

We prove the existence and multiplicity of nontrivial solutions for a fourth order problem ${\Delta}^2u+c{\Delta}u={\alpha}u-{\beta}(u+1)^-$ in ${\Omega}$, ${\Delta}u=0$ and $u=0$ on ${\partial}{\Omega}$, where ${\lambda}_1{\leq}c{\leq}{\lambda}_2$ (where $({\lambda}_i)_{i{\geq}1}$ is the sequence of the eigenvalues of $-{\Delta}$ in$H_0^1({\Omega})$) and ${\Omega}$ is a bounded open set in $R^N$ with smooth boundary ${\partial}{\Omega}$. The results are proved by applying minimax arguments and linking theory.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 I
• /
• pp.73-78
• /
• 2001

Main sources of the vibration of a gear-pair system are backlash and transmission error. This paper investigates the dynamics of a gear-pair system involving backlash and transmission error. This paper presented 4 types of gear motions due to the existence of a backlash. The solutions are calculated using a multiple-time scale method and numerically. The results shows the existence of 4 type motions, jump phenomenon, and chaotic motion consequently the design of gear driving system with low vibration and noise requires the study on the effects of transmission error and backlash, i.e. nonlinearities in gear driving system.

• 농촌지도와개발
• /
• 제17권4호
• /
• pp.897-918
• /
• 2010

This paper researches conservative value evaluation of rural tourism villages with "CVM(Contingent Valuation Method)" focusing on visitor to offer the guide for preservation and management in landscape of rural tourism villages based on critical consciousness for conservation and utilization by regional development. The option value is 37,624won(36.7%), the bequest value is 34,856won(34.0%), existence value is 30,073 won(29.3%), and overall average willingness to pay of conservation value is 102,517won(100.0%) for conservative value of sesim-village in Kyung-Ju. The results show that landscape of rural tourism villages has great value historically and culturally. In conclusion, it suggested that planners and staffs of rural tourism villages recognize that it is positively necessary to be considered not only multiple landscape index but also conservation policy in process of development planning in rural tourism villages.

• Journal of applied mathematics & informatics
• /
• 제14권1_2호
• /
• pp.1-37
• /
• 2004

We consider the following system of discrete equations $u_i(\kappa)\;=\;{\Sigma{N}{\ell=0}}g_i({\kappa},\;{\ell})f_i(\ell,\;u_1(\ell),\;u_2(\ell),\;{\cdots}\;,\;u_n(\ell)),\;{\kappa}\;{\in}\;\{0,\;1,\;{\cdots}\;,\;T\},\;1\;{\leq}\;i\;{\leq}\;n\;where\;T\;{\geq}\;N\;>\;0,\;1\;{\leq}i\;{\leq}\;n$. Existence criteria for single, double and multiple constant-sign solutions of the system are established. To illustrate the generality of the results obtained, we include applications to several well known boundary value problems. The above system is also extended to that on $\{0,\;1,\;{\cdots}\;\}\;u_i(\kappa)\;=\;{\Sigma{\infty}{\ell=0}}g_i({\kappa},\;{\ell})f_i(\ell,\;u_1(\ell),\;u_2(\ell),\;\cdots\;,\;u_n(\ell)),\;{\kappa}\;{\in}\;\{0,\;1,\;{\cdots}\;\},\;1\;{\leq}\;i\;{\leq}\;n$ for which the existence of constant-sign solutions is investigated.

• 대한수학회보
• /
• 제49권1호
• /
• pp.175-195
• /
• 2012

Representing planar Pythagorean hodograph (PH) curves by the complex roots of their hodographs, we standardize Farouki's double cubic method to become the undetermined junction point (UJP) method, and then prove the generic existence of solutions for general $C^1$ Hermite interpolation problems. We also extend the UJP method to solve $C^2$ Hermite interpolation problems with multiple PH cubics, and also prove the generic existence of solutions which consist of triple PH cubics with $C^1$ junction points. Further generalizing the UJP method, we go on to solve $C^2$ Hermite interpolation problems using two PH quintics with a $C^1$ junction point, and we also show the possibility of applying the modi e UJP method to $G^2[C^1]$ Hermite interpolation.

• East Asian mathematical journal
• /
• 제40권3호
• /
• pp.295-306
• /
• 2024

We investigate the existence of multiple positive solutions of the following elliptic equation with a Schrödinger-type term: $$\begin{cases}-{\Delta}u+V(x)u={\lambda}f(u){\quad} x{\in}{\Omega},\\{\qquad}{\qquad}{\quad}u=0, {\qquad}\;x{\in}\partial{\Omega},\end{cases}$$, where 0 ∈ Ω is a bounded domain in ℝ^N , N ≥ 1, with a smooth boundary ∂Ω, f ∈ C[0, ∞), V ∈ L^∞(Ω) and λ is a positive parameter. In particular, when f(s) > 0 for 0 ≤ s < σ and f(s) < 0 for s > σ, we establish the existence of at least three positive solutions for a certain range of λ by using the method of sub and supersolutions.

• Journal of Mechanical Science and Technology
• /
• 제16권4호
• /
• pp.427-435
• /
• 2002

This paper presents a development result for image processed tracking system of multiple moving objects based on Kalman filter and a simple window tracking method. The proposed algorithm of foreground detection and background adaptation (FDBA) is composed of three modules: a block checking module(BCM), an object movement prediction module(OMPM), and an adaptive background estimation module (ABEM). The BCM is processed for checking the existence of objects. To speed up the image processing time and to precisely track multiple objects under the object's mergence, a concept of a simple window tracking method is adopted in the OMPM. The ABEM separates the foreground from the background in the reset simple tracking window in the OMPM. It is shown through experimental results that the proposed FDBA algorithm is robustly adaptable to the background variation in a short processing time. Furthermore, it is shown that the proposed method can solve the problems of mergence, cross and split that are brought up in the case of tracking multiple moving objects.

• 한국통신학회논문지
• /
• 제19권4호
• /
• pp.605-613
• /
• 1994

본 논문에서는 CSMA 다중 access 방식으로 분산 무선 통신망을 구현할 때 다중 access 방식의 성능을 비교하였다. 또한 숨겨진 노드가 존재하거나 전자파 장애로 인한 CSMA방식의 성능 저하의 원인을 개설 할 수 있는 프로토콜을 제안하여 성능을 개선하였다. 숨겨진 노드가 존재하는 상황에서 CSMA의 방식을 개선하기 위해 중앙 집중식망에서 ISMA(Idle Signal Multiple Access), BTMA(Busy Tone Multiple Access), BCMA(Busy Channel Multiple Access)등 과 같은 채널 access 방식을 사용하였다. 본 논문에서는 중앙 집중식이 아닌 분산이면서 독립적인 노드로 통신하는 환경에서 숨겨진 노드가 존재하거나 전자파 방애로 인한 노드들이 있는 경우 성능 개선을 위해 프로토콜을 제안하였다. 새로운 프로토콜을 이용하여 컴퓨터 모의실험(simulation)을 함으로써 처리율(throughput)과 전송성공 확률이 실질적으로 개선됨을 확인하였다. 모의실험은 OPNET simulator를 사용하였다.

• Asia Marketing Journal
• /
• 제18권4호
• /
• pp.125-138
• /
• 2017

The goal of the study is to understand how consumers' constraint as opposed to utility structure gives rise to final decision when consumers purchase more than one variant of product at a time, i.e., horizontal variety seeking or multiple-discreteness. Purchase and consumption decision not only produces utility but also involves some sort of cognitive pressure. Past consumption or last purchase is likely to be linked to this burden we face such as concern for obesity, risk of harm, and guilt for mischief. In this research, the existence and the role of dynamic constraint are investigated through a microeconomic utility model with multiple dynamic constraint. The model is applied to the salty snacks data collected from field study where burden for spiciness serves as a constraint. The results are compared to the conventional multiple discreteness choice models of static constraints, and policy implications on price discounts is explored. The major findings are that first, one would underestimate the level of consumer preference for product offerings when ignoring the carry-over of the concern from the past consumption, and second, the impact of price promotion on demand would be properly evaluated when the model allows for the role of constraint as both multiple and dynamic. The current study is different from the existing studies in two ways. First, it captures the effect of 'mental constraint' on demand in formal economic model. Second, unlike the state dependence well documented in the literature, the study proposes the notion of state dependence in different way, via constraint rather than utility.

• 구강회복응용과학지
• /
• 제31권1호
• /
• pp.10-19
• /
• 2015

목적: 이 연구는 임플란트의 장기간 생존율을 후향적으로 평가하고, 이에 영향을 미치는 요인을 분석하는 것이었다. 연구 재료 및 방법: 1998년 1월부터 2012년 12월까지 강릉원주대학교 치과병원 치주과에서 식립된 임플란트 중 2013년 6월까지 주기적으로 검사가 이루어지고 있는 2265개의 임플란트를 대상으로 하였다. 환자의 진료기록부와 방사선 사진을 통해 성별, 연령, 흡연 여부, 임플란트 직경, 임플란트 길이, 임플란트 표면, 임플란트 식립 부위, 동반된 술식, 합병증 유무에 대한 자료를 조사하였다. 결과: 임플란트 식립 후 보철 전 생존율은 98.9%, 보철 후 5년간 누적생존율은 97.2%, 15년간 누적생존율은 95.2% 이었다. 단순로지스틱회귀분석 시 성별, 흡연 여부, 임플란트 식립 부위 및 합병증 유무가 임플란트 실패와 유의하게 관련되었다. 이 변수들로 다중로지스틱회귀분석을 시행한 결과, 흡연 여부와 합병증 유무만이 임플란트 실패와 유의하게 관련된 것으로 나타났다. 결론: 2265개의 임플란트를 대상으로 15년간의 누적생존율을 조사한 결과 95.2% 이었다. 흡연가이거나, 임플란트 합병증이 존재할 경우 임플란트의 실패율이 유의하게 증가되었다.