• 한국자동차공학회논문집
• /
• 제14권6호
• /
• pp.89-94
• /
• 2006

The tire delivering power generated from engine to the ground pulls a vehicle to move. Radius of tires is changeable due to elasticity that depends on the speed of vehicle and traction force. The main objectives on this study are real time measurement of dynamic radius and slip ratio according to the speed and traction force. The dynamic radius is proportional to speed and traction force. According to measurement, the dynamic radius is increased about 3mm under 100km/h compared to stop. It is also increased about 1.5mm when a traction force is supplied as much as 4kN compared to no load state at low speed. There is no strong relationship between slip ratio and vehicle speed. The slip ratio is measured up to 4% under WOT at first stage gear. Through this research, the method of measuring dynamic radius and slip ratio is set up and is expected to be applied to the measurement of traction force in chassis dynamometer or accelerating and climbing ability.

• 한국정밀공학회지
• /
• 제7권3호
• /
• pp.37-47
• /
• 1990

In accordance with the high precision of mechanical elements, it has been required to high precision in surface roughness measurement and, therefore, stylus tip radius is manufa- ctured less than 2 .mu. m through ion sputter machining. In this experiment, by suing ion sputter machined stylus pf fine tip, radius and lapping machined stylus, surface roughness of standard specimens, silicon wafer were measured and then Rmax, Ra, RMS value were investi- gatedaccording to the variation of tip radius of stylus. As a result, measuring error due to the variation of stylus tip radius in surface roughness measurement was decreased by using ion sputter machined stylus and also the measuring accuracy was improved. And the measuring variation of Ra, RMS calculated from correlation coefficient lager than 0.9 on the wave of short period and amplitude using ion sputter machined stylus of fine tip radius.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2007년도 추계 학술대회논문집
• /
• pp.127-133
• /
• 2007

This paper represents the numerical study on Taylor flow according to the radius ratio and the angular velocity for flow between tow cylinder. The numerical model is consisted of two cylinder which inner cylinder is rotating and outer cylinder is fix, and the axial direction is used the cyclic condition because of the length for axial direction is assumed infinite. The diameter of inner cylinder is assumed 86.8 mm, the numerical parameters are angular velocity and radius ratio. The numerical method is compared with the experimental results by Wereley, and the results are very good agreement. The critical Taylor number is calculated by theoretical and numerical analysis, and the results is showed the difference about ${\pm}10\;%$. As $Re/Re_c$ is increased, Taylor vortex is changed to wavy vortex, and then the wave number for azimuthal direction is increased. Azimuthal wave according to the radius ratio is showed high amplitude and low frequence in case of small radius ratio, and is showed low amplitude and high frequence in case of large radius ratio.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
• /
• 제9권5호
• /
• pp.567-577
• /
• 2003

GPRS 망으로 이동한 이동 ISP 가입자는 자신의 홈 ISP 망을 접속하여 무선 인터넷 서비스를 받기 위해 홈 ISP 망으로부터 인증을 받고 IP를 할당받아야 한다. 이에 본 논문에서는 GPRS 망으로 이동한 이동 ISP 가입자의 인증 처리를 위해 PPP CHAP과 RADIUS 인증 서버의 연계 방안을 제시한다. 이를 위해 우선 이동 ISP 망 가입자의 단말에서 정의되어야 할 인증 메시지 구조와 GPRS 망 게이트웨이에서 구현될 메시지 구조를 제시한다. 아울러 GGSN과 ISP 망간의 인증 메시지 구조 정의를 기반으로 제안된 내용에 대해 시험 환경 구축을 통해 실제 시뮬레이션 결과를 보였다.

• 유통과학연구
• /
• 제17권12호
• /
• pp.63-70
• /
• 2019

Purpose: This study was to propose effective deployment of automatic external defibrillators (AEDs) installed at general supermarkets. Research design, data, and methodology : We conducted interview and data surveys on 72 large distributors in Seoul and Gyeonggi province in South Korea. The content of this survey was consisted of general status on the general supermarkets, AED deployment and management regarding public access defibrillation (PAD). G^⁎Power (v 3.1.9.4; Universität Kiel, Kiel, Germany) was also used to analyze statistical power. Radius and actual distance, radius and retrieval time were compared by t-test at α=.05. respectively. Results : Difference between the radius (102.7 meters) and the actual distance (187.8 meters) was 85.1m, it had statistically significant difference (p<.001). The actual distance was longer compared to the radius distance. Difference between the radius (114.1 seconds) and the retrieval time (208.7 seconds) was 94.6s, it had statistically significant difference (p<.001). The retrieval time took longer compared to the radius time as well. Conclusions : The finding shows that only 45.9% of the general supermarkets are satisfied with the actual AED coverage within 3 minutes. This needs to enhance AED deployment to reduce defibrillation time and AED management to boost application in South Korea.

• 호남수학학술지
• /
• 제18권1호
• /
• pp.59-77
• /
• 1996

In this paper, we study how the second coefficient in the power series expansion of functions in $P_n$(a; b, M), $F_n$(a; b, M) and $G_n$(a; b, M) influences certain properties like distortion, ${\gamma}-spiral$ radius and radius of starlikeness of these classes.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
• /
• pp.7-10
• /
• 2003

This paper proposes the multiple objects focusing algorithm. Given multiple objects at different distances from a camera, we assume that one object is well-focused and the others are out-of-focused. The proposed auto-focusing algorithm is summarized as follows: (i) detects edges from an input image, (ⅱ) estimates the radius of PSF (Point Spread Function) across the edge, (ⅲ) gather edge points having same radius of PSF, (ⅳ) segments the image into regions with the same radius of PSF, and (ⅴ) restores the each segmented region using the corresponding PSF.

• Kyungpook Mathematical Journal
• /
• 제54권3호
• /
• pp.425-441
• /
• 2014

In this paper, we first present the properties of the graph which maximize the spectral radius among all graphs with prescribed degree sequence. Using these results, we provide a somewhat simpler method to determine the unicyclic graph with maximum spectral radius among all unicyclic graphs with a given degree sequence. Moreover, we determine the bicyclic graph which has maximum spectral radius among all bicyclic graphs with a given degree sequence.

• East Asian mathematical journal
• /
• 제37권3호
• /
• pp.295-305
• /
• 2021

In this paper, we analyze the efficiency of a domain decomposition method for the two-dimensional telegraph equations. We formulate the theoretical spectral radius of the iteration matrix generated by the domain decomposition method, because the rate of convergence of an iterative algorithm depends on the spectral radius of the iteration matrix. The theoretical spectral radius is confirmed by the experimental one using MATLAB. Speedup and operation ratio of the domain decomposition method are also compared as the two measurements of the efficiency of the method. Numerical results support the high efficiency of the domain decomposition method.

• Kyungpook Mathematical Journal
• /
• 제61권4호
• /
• pp.845-858
• /
• 2021

We present new bounds for the numerical radius of bounded linear operators and 2 × 2 operator matrices. We apply upper bounds for the numerical radius to the Frobenius companion matrix of a complex monic polynomial to obtain new estimations for the zeros of that polynomial. We also show with numerical examples that our new estimations improve on the existing estimations.