• Journal of Welding and Joining
• /
• 제28권2호
• /
• pp.91-95
• /
• 2010

Stress distribution and deformation on the CT-type(Cross Tension type) spot welded lap joint subjected to out of plane tensile load were investigated by finite element method. Using the maximum principal stresses at the nugget edge obtained by FEM analysis, evaluated the fatigue strength of the CT-type spot welded lap joints having various dimensions and materials. and also, the influence of the geometrical parameters of CT-type spot welded lap joints on stress distribution and fatigue strength must be evaluated. thus, in this paper, ${\Delta}P-N_f$ curve were obtained by fatigue tests. Using these results, ${\Delta}P-N_f$ curve were systematically rearranged in the $\Delta\sigma-N_f$ relation with the hot spot stresses at the CT-type spot welded lab joints. It was found that the proposed $\Delta\sigma-N_f$ relation could provide a more reasonable fatigue design criterion for the CT-type spot welded lap joints.

• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제17권4호
• /
• pp.389-396
• /
• 2010

We investigate the existence of homoclinic orbits of the following systems of $Li{\'{e}}nard$ type: $a(x)x^'=h(y)-F(x)$, $y^'$=-a(x)g(x), where $h(y)=m{\mid}y{\mid}^{p-2}y$ with m > 0 and p > 1 and a, F, 9 are continuous functions such that a(x) > 0 for all $x{\in}{\mathbb{R}}$ and F(0)=g(0)=0 and xg(x) > 0 for $x{\neq}0$. By a series of time and coordinates transformations of the above system, we obtain sufficient conditions for the positive orbits of the above system starting at the points on the curve h(y) = F(x) with x > 0 to approach the origin through only the first quadrant. The method of this paper is new and the results of this paper cover some early results on this topic.

• 대한전자공학회논문지
• /
• 제26권6호
• /
• pp.7-14
• /
• 1989

본 논문에서는 R-P 시스템의 특이성 회피 기능을 갖는 경로제어 방법에 관하여 논하였다. 먼저 R-P 시스템을 하나의 기구학적 모델로 하여 여유자유도를 갖는 Manippulator 제어 문제로 유도하였다. 또한 R-P 시스템의 특이성을 해식적으로 분석 고찰한 후 (내부)특이성일때 이를 회피하면서 경로오차를 허용범위내에 있도록 하기 위하여 DLS(damped least square)의 Damping Factor를 가변시켜 주는 방법을 제시하였다. 제시된 방법의 타당성을 보이기 위하여 5자유도를 갖는 Rhino 로보트와 2자유도를 갖는 포지셔널을 대상으로 조작성능지수(manipulability)를 최대화하는 방법, 고정 Damping Factor를 갖는 DLS 방법과 제시된 가변 Damping을 갖는 DLS 방법을 컴퓨터 시뮬레이션을 통하여 경로오차와 성능지수 및 관절속도에 관점을 두어 비교 검토하였다.

• 한국산학기술학회논문지
• /
• 제16권7호
• /
• pp.4398-4404
• /
• 2015

스테인리스 강판은 동적기계구조물을 제작하기 위한 구조용 재료로 널리 사용된다. 또한 이들을 일체화 시키는 방법으로 가스용접을 많이 사용하게 되는데 가스용접에는 다양한 종류에 의해 구조물을 일체화 시킨다. 따라서 부재와 부재를 연결하는 용접부에 대한 응력분포 및 피로강도평가는 구조물의 건전성 및 수명을 연구하는데 매우 중요한 요소가 된다. 그래서 본 연구에서는 피로시험에 의해서 얻어지는 ${\Delta}P-N_f$ 관계를 유한요소해석법에 의해서 최대주응력으로 ${\Delta}{\sigma}-N_f$ 관계로 나타내어 피로설계기준을 정하였고, 이 결과를 이용해서 확률론적 통계해석기법을 적용해서 가속식을 추정하여 임의의 목표수명을 예측할 수 있는 신뢰성설계기술기법을 제시하고자 하였다.

• Journal of applied mathematics & informatics
• /
• 제27권5_6호
• /
• pp.1165-1176
• /
• 2009

This paper is concerned with the interval oscillation of the second order nonlinear ordinary differential equation (r(t)|y'(t)|$^{{\alpha}-1}$ y'(t))'+p(t)|y'(t)|$^{{\alpha}-1}$ y'(t)+q(t)f(y(t))g(y'(t))=0. By constructing ageneralized Riccati transformation and using the method of averaging techniques, we establish some interval oscillation criteria when f(y) is not differetiable but satisfies the condition $\frac{f(y)}{|y|^{{\alpha}-1}y}$ ${\geq}{\mu}_0$ > 0 for $y{\neq}0$.

• 대한수학회논문집
• /
• 제32권2호
• /
• pp.435-445
• /
• 2017

Let D be a directed graph with p vertices and q arcs. A vertex out-magic total labeling is a bijection f from $V(D){\cup}A(D){\rightarrow}\{1,2,{\ldots},p+q\}$ with the property that for every $v{\in}V(D)$, $f(v)+\sum_{u{\in}O(v)}f((v,u))=k$, for some constant k. Such a labeling is called a V-super vertex out-magic total labeling (V-SVOMT labeling) if $f(V(D))=\{1,2,3,{\ldots},p\}$. A digraph D is called a V-super vertex out-magic total digraph (V-SVOMT digraph) if D admits a V-SVOMT labeling. In this paper, we provide a method to find the most vital nodes in a network by introducing the above labeling and we study the basic properties of such labelings for digraphs. In particular, we completely solve the problem of finding V-SVOMT labeling of generalized de Bruijn digraphs which are used in the interconnection network topologies.

• 센서학회지
• /
• 제19권1호
• /
• pp.1-7
• /
• 2010

Electrostatic capacitance measurement method in a fine hose was proposed, in which two ring-type electrodes were disposed on the hose in the direction of fluid flow instead of the conventional face-to-face electrodes. With the proposed electrode structure, we realized a Ringer's solution exhaustion detector for an IV(invasive vein) injection set. On a 4 mm-diameter hose of IV set, we disposed two ring-type electrodes of 10 mm width at a distance of 5 mm each other and obtained 0.72 pF and 2.51 pF for air and 10 % dextrose Ringer's solution in the hose, respectively. The capacitance between the two electrodes varied with the hose-wraparound coverage of electrode as well as the width of electrode and the distance between the electrodes. For hose-wraparound electrode coverage of 75 %, the capacitance varied from 0.62 pF to 1.98 pF with the Ringer's solution level between the two electrodes. A charge amplifier converted the capacitance. variation into electric signal and a comparator was used to detect whether Ringer's solution was exhausted or not. The result was delivered to a host using a RF transmitter with 320 MHz carrier frequency.

• 한국보건간호학회지
• /
• 제25권2호
• /
• pp.255-265
• /
• 2011

Purpose: The study investigated the knowledge and actual condition of sexuallytransmitted diseases(STD) in Mongoloian. Method: Data from 210 Mongolians were collected for 6days from August 10-15, 2008 using a questionnaire translated by Mongolians to identify the knowledge of STD and with permission, analysis of blood and human immuno deficiency virus(HIV) by SD Bioline Syphilis 3.2 test and SD Bioline HIV-1/2 3.0 test respectively. The data was scored by mean ${\pm}$ standard deviation. Differences were evaluated according to the subjects' general characteristics by t-test and the ANOVA. Results: The average knowledge score concerning STD 48.99(${\pm}.19$) indicated a low level of knowledge. STD was detected in six(2.9%) and HIV was four(1.9%) of the 210 subjects. General characteristics significantly different knowledge level were gender(t=-3.098, p=.002), education(F=6.090, p=.003), type of employment(F=2.443, p=.049), and sexual education experience(F=5.604, p=.004). Conclusion: Education programs to increase STD awareness and its prevention must be developed and regular health evaluations for those already have sexual transmitted disease is needed.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 2006년도 춘계학술대회 학술발표 논문집 제16권 제1호
• /
• pp.199-202
• /
• 2006

We propose some properties of fuzzy p-value and fuzzy significance level to the test statistics for the fuzzy hypotheses testing. Appling the principle of agreement index, we suggest two method for fuzzy hypothesis testing by fuzzy rejection region and fuzzy p-value with fuzzy hypothesis $H_{f,0}$.

• 재활간호학회지
• /
• 제11권2호
• /
• pp.90-98
• /
• 2008

Purpose: The purpose of this study was to examine the cognitive function and degree of dementia patient by doing clock drawing test and to explore the relationship among other dementia screening test. Method: The study subjects were 94 dementia in patients department. The data was collected by face to face interview by clinical psychologist from January 2007 to February 2008. The tools were Clock Drawing Test, K-MMSE, K-3MS and CDR Scale. Results: 1) The average score of CDT was 5.13 (2.54), of K-MMSE was 20.53 (4.85), of K-3MS was 61.66 (16.46), and of CDR was 1.2 (.72), those scores showed dementia. 2) There was a statistically the significant difference in CDT (F=2.83, p=.043) and CDR (F=2.00, p=.008) by age. CDT has shown the differences by gender (t=-2.42, p=.018) and education (F=7.66, p=.000). 3) There were significant relationships between CDT and K-MMSE (r=-.294. p=.004), K-3MS (r=-.335, p=.001), and CDR (r=.286, p=.008). Conclusion: It is believed that using CDT which measures the visuospatial ability of dementia patients and K-MMSE which assesses an ability of language and orientation and K-3MS at the same time helps examining the beginning and the progressive degree of dementia more easily and objectively.