• 한국통신학회논문지
• /
• 제32권11A호
• /
• pp.1086-1095
• /
• 2007

본 논문에서는 다수의 피코넷들이 공존 (Simultaneously Operating Piconets; SOP) 하는 환경하에서 다중 상관처리를 이용한 새로운 Non-coherent TOA 추정 기법을 제안한다. SOP 환경에서 각 피코넷들을 구분하기 위해서 Gold 시퀀스를 이용한 DSSS (Direct Sequence Spread Spectrum) 기반의 IR-UWB (Impulse Radio-Ultra WideBand) 신호를 사용하였으며 상관 특성을 개선시키기 위해서 다중 마스트 처리 (Multiple Mask Operation; MMO) 방안을 제시하였다. 직접 LOS 경로에 대한 도착 시간 (Time Of Arrival; TOA) 정보는 2단계의 대략적인(Coarse)/ 정밀 (Fine) 타이밍 검출 과정을 통해 획득된다. 제안된 기법에 대한 성능을 검증하기 위해서 IEEE 802.15.4a TG (Task Group)에서 제시한 두 채널 모델을 적용하였고 시뮬레이션 결과로부터 제안된 기법이 다수개의 피코넷이 공존하는 다중 경로 환경에서 일반적인 단일 상관 처리 기법보다 성능이 개선됨을 확인하였다.

• 대한가정학회지
• /
• 제28권1호
• /
• pp.105-124
• /
• 1990

The purpose of this study is to investigate 1) the level of the city housewives' sense and behavior of wedding and ancestral service according to the background variables, 2) the relationship of the sense of wedding and ancestral service and behavior, and 3) what the most influential factors are. For the purpose of this study, 700 questionnaire were distributed to the housewives who live in Seoul and collected during the February 1989. And the measuring instruments are composed of 9 questions, 11 questions of the sense of wedding service, 12 questions of the sense of ancestral service, 11 questions of the behavior of wedding service, and 12 questions of the behavior of ancestral service. To obtain the sense and behavior of wedding and ancestral service scale, item analysis through Pearon's correlation and factor analysis, frequency distribution, percentile, mean, standard deviation, t-test, F-test, Pearson's γ, Paired-t-test, Duncan's Multiple Range Test, and Stepwise multiple Regression were used for data analysis. The major fidnigs are as follows: 1. The general tendency of the city housewives' sense of wedding service was modern. That of the city housewives' sense of ancestral service was the mid level of the traditional and the modern. According to background variable (ie: age, educational level, the number of children, the duration of marriage, religion, the existence of job, the existence of married son and daughter), the city housewives' sense of wedding service is different significantly. Accoring to background variable(ie: age, educational level, the average home income a month, the number of children, the duration of marriage, religion, the existence of married son and daughter), the city housewives' sense of ancestral service is different significantly. 2. The general tendency of the city housewives' behavior of wedding service was modern. That of the city housewives' behavior of ancestral service was somewhat modern. According to background variable(ie: age, educational level, the number of children, the duration of marriage, the existence of married son and daughter, the form of family), the city housewives' behavior of wedding service is different significantly. According to background variable(ie" age, educational level, the number of children, the duration of marriage, religion, the existence of job, the existence of married son and daughter), the city housewives' behavior of ancestral service is different significantly. 3. There were positive correlation between the city housewive' sense and behavior of wedding and ancestral service(P<.001). And the housewives' sense of wedding service was modernized than that of ancestral service, the housewives' behavior of ancestral service was modernized than that of wedding service. 4. The city housewives' sense of wedding service was the duration of marriage(β=-.226), influential factor. And influential factors on that of ancestral service were educational level(β=.250), the existence of married son and daughter(β=-.123), number of children(β=-.101). The influential factors on the city housewives' behavior of wedding service were age(β=-.193), the form of family(β=.097). And that of ancestral service were educational level(β=165), the number of children(β=-.157).

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
• /
• pp.27-30
• /
• 1991

Recently, the phenomena of voltage instability have become major concern in power system, these phenomena are closely related to what are called multiple load flow solutions and calculation methods on these solutions have developed. The multiple solutions concerned with phenomena are pair solutions in heavy loaded contion. But conventional methods require much run time to find this pair solutions and unusual generation patten in the condition of multiple solutions. In this paper, by using concept of existence condition of multiple solutions, calculation method on the multiple load flow solutions is presented which find the pair solutions in light loaded condintion.

• Journal of applied mathematics & informatics
• /
• 제31권1_2호
• /
• pp.27-34
• /
• 2013

In this paper, we consider the Duffing type p-Laplacian equation with multiple deviating arguments of the form $$({\varphi}_p(x^{\prime}(t)))^{\prime}+Cx^{\prime}(t)+go(t,x(t))+\sum_{k=1}^ngk(t,x(t-{\tau}_k(t)))=e(t)$$. By using the coincidence degree theory, we establish new results on the existence and uniqueness of periodic solutions for the above equation. Moreover, an example is given to illustrate the effectiveness of our results.

• Korean Journal of Mathematics
• /
• 제17권2호
• /
• pp.197-210
• /
• 2009

We prove the existence of multiple solutions (${\xi},{\eta}$) for perturbations of the elliptic system with Dirichlet boundary condition $$(0.1)\;\begin{array}{lcr}A{\xi}+g_1({\xi}+ 2{\eta})=s{\phi}_1+h\;in\;{\Omega},\\A{\xi}+g_2({\xi}+ 2{\eta})=s{\phi}_1+h\;in\;{\Omega},\end{array}$$ where $lim_{u{\rightarrow}{\infty}}\frac{gj(u)}{u}={\beta}_j$, $lim_{u{\rightarrow}-{\infty}}\frac{gj(u)}{u}={\alpha}_j$ are finite and the nonlinearity $g_1+2g_2$ crosses eigenvalues of A.

• Korean Journal of Mathematics
• /
• 제17권2호
• /
• pp.211-218
• /
• 2009

We investigate the multiple solutions for a suspending beam equation with jumping nonlinearity crossing three eigenvalues, with Dirichlet boundary condition and periodic condition. We show the existence of at least six nontrivial periodic solutions for the equation by using the finite dimensional reduction method and the geometry of the mapping.

• Journal of applied mathematics & informatics
• /
• 제30권1_2호
• /
• pp.305-320
• /
• 2012

In this paper, we study a class of integral boundary value problems for fractional differential equations. By using some fixed point theorems, the results of existence of at least three positive solutions for the boundary value problems are obtained.

• 충청수학회지
• /
• 제22권2호
• /
• pp.251-259
• /
• 2009

We investigate the multiple solutions for the nonlinear parabolic boundary value problem with jumping nonlinearity crossing two eigenvalues. We show the existence of at least four nontrivial periodic solutions for the parabolic boundary value problem. We restrict ourselves to the real Hilbert space and obtain this result by the geometry of the mapping.

• 충청수학회지
• /
• 제28권2호
• /
• pp.173-186
• /
• 2015

In this paper, we consider a discrete fractional nonlinear boundary value problem in which nonlinear term f is involved with the fractional order difference. We transform the fractional boundary value problem into boundary value problem of integer order difference equation. By using a generalization of Leggett-Williams fixed-point theorem due to Avery and Peterson, we provide sufficient conditions for the existence of at least three positive solutions.

• Korean Journal of Mathematics
• /
• 제9권2호
• /
• pp.133-147
• /
• 2001

In this paper, we introduce the concepts of multiple $L_p$ analytic Fourier-Feynman transform ($1{\leq}p$ < ${\infty})$ and a convolution product of functionals on abstract Wiener space and verify the existence of the multiple $L_p$ analytic Fourier-Feynman transform for functionls in the Fresnel class. Moreover, we verify that the Fresnel class is closed under the $L_p$ analytic Fourier-Feynman transformation and the convolution product, respectively. And we establish some relationships among the multiple $L_p$ analytic Fourier-Feynman transform and the convolution product on the Fresnel class.