• 대한토목학회논문집
• /
• 제41권1호
• /
• pp.49-56
• /
• 2021

본 연구의 목적은 CRP (Continuous Risk Profile) 분석을 이용하여 야간에만 교통사고가 많이 발생하는 야간 특화 교통사고 다발구간을 선정하는 방법론을 개발하는 것이다. 또한 이연구의 다른 목적은 CRP 분석을 이용하여 야간 특화 교통사고 다발구간의 특성을 제시하는 것이다. 본 연구에서 CRP 분석은 실제 교통사고 데이터를 이용하며 대상 노선의 교통량 고려해 분석되었다. 또한 CRP 분석에 사용되는 변수는 국내 고속도로의 실정에 적합한 변수로 선정하였다. 본 연구에서는 야간 특화 교통사고를 분석하기 위한 방법으로 야간 CRP에서 주간 CRP를 빼는 방법을 사용하였다. 결과적으로 CRP 분석을 사용하여 야간 특화 교통사고 다발구간을 선정할 수 있었다. 또한 야간 특화 교통사고 다발구간은 IC나 터널이 설치된 구간으로 일반구간과 편차가 있었다. 결론적으로, 야간 특화 교통사고 다발구간 산정에 CRP 분석을 사용할 수 있었으며, IC 또는 터널시설이 설치된 구간에서 야간 특화 교통사고가 많이 발생하여 개선이 필요한 지점으로 선정되었다. 또한 IC 또는 터널시설이 설치된 구간에서 야간 특화 교통사고가 많이 발생한 것은 조명시설로 인한 야간 시인성의 문제에서 요인한 것으로 추론된다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
• /
• pp.311-319
• /
• 2011

Track accompanies the process that track alignment by traffic loads is changed. A change of track alignment affects the running safety and riding comfort of train. This is called a track irregularity. The most important task in maintaining the track is to manage these track irregularity within quality parameters. Today, track maintenance of urban transit is enforcing immediate maintenance about section exceeding a safety standard by applying track recording data got through Integrated Measurement. This method is advantage of being easy of the maintenance assesment in case of the running safety, but is disadvantage of being difficult in case of the riding comfort of train. In this study, we propose track irregularity deviation of each track system depending on the time series and present about utilization plans of the Track Irregularity Progress Rate.

• 화약ㆍ발파
• /
• 제30권1호
• /
• pp.1-8
• /
• 2012

본 연구에서는 충격 하중을 받은 콘크리트 재료의 내부 주응력 변화를 확인하기 위하여 Visual FEA 유한요소 프로그램으로 콘크리트 재료의 단면을 모델링하여 절점에서의 최대주응력을 분석하였다. 결과적으로, 콘크리트 재료의 탄성계수가 작을수록 최대주응력은 증가하는 것으로 나타났고, 콘크리트 재료의 물성 변화에 따라 최대주응력 편차는 2~3배 차이를 나타냈다.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 춘계학술대회 논문집
• /
• pp.19-22
• /
• 2004

A scheme of shape optimization by new approximation approach is applied to design of a flow guide in three-dimensional extrusion processes. The optimization scheme is presented to reduce computation time fur the optimization process and applied to an H-section extrusion problem for verifying the efficiency and the usefulness. The object of optimization is to minimize the deviation of exit velocity and control points of a Bezier curve describing the shape of the flow guide are regarded as design variables. The effectiveness of the proposed scheme is then demonstrated through the applied example.

• 천문학회보
• /
• 제43권1호
• /
• pp.35.3-35.3
• /
• 2018

Incorporating the fully quantum mechanical computation of scattering cross-section and statistical moment analysis of absorption profiles, we investigate the Lyman line asymmetry of extremely high column density systems. Recent high redshift observations detected strong damped Lyman alpha systems (DLAs) whose column density is larger than N_HI ~ [10]^21.3 cm^(-2). Absorption profiles of these DLAs are characterized by the broad and asymmetric damping wing. For accurate description of radiation damping, the second-order time-dependent perturbation theory is adopted. To quantitatively address line asymmetry, we define a distribution function for each Lyman line, and compute statistical moments (mean, standard deviation, skewness and kurtosis) regarding column densities N_HI > [10]^18 cm^(-2). In this work, we present statistical properties of the intrinsic line profiles, and compare them with the Lorentzian cases.

• 대한가정학회지
• /
• 제42권12호
• /
• pp.31-54
• /
• 2004

The purpose of this research is to exam the attitudes of elderly people to dating. This research also investigates the differences of the elderly's attitudes to dating based on demographic, family relation, and social relation variables. Attitudes to elderly dating in this study included the perception, necessity, and difficulty of elderly dating. The sample consisted of 689 elderly Korean people. Data were analyzed by frequencies, mean, standard deviation, Chi-square test, t-test, and F-test. The results showed that there were statistically significant differences in elderly attitudes to dating according to demographic, family relation, and social relation variables. The findings of this study are described in the results section and the implications of these research findings are discussed.

• Structural Engineering and Mechanics
• /
• 제56권5호
• /
• pp.767-785
• /
• 2015

The stochastic finite element method is employed to obtain a stochastic dynamic model of angled beams subjected to impact loads when uncertain material properties are described by random fields. Using the perturbation technique in conjunction with a precise time integration method, a random analysis approach is developed for efficient analysis of random elastic waves. Formulas for the mean, variance and covariance of displacement, strain and stress are introduced. Statistics of displacement and stress waves is analyzed and effects of bend angle and material stochasticity on wave propagation are studied. It is found that the elastic wave correlation in the angled section is the most significant. The mean, variance and covariance of the stress wave amplitude decrease with an increase in bend angle. The standard deviation of the beam material density plays an important role in longitudinal displacement wave covariance.

• 설비공학논문집
• /
• 제12권6호
• /
• pp.561-569
• /
• 2000

Single phase and condensation heat transfer characteristics of ammonia in a horizontal tube have been investigated experimentally The horizontal test section is composed of smooth SUS316 tube for refrigerant flow, surrounding annulus for water flow, and temperature and Pressure measuring sensors. For single phase test, subcooled ammonia mass flux was varied from 320 to 501 kg/mrs and temperature was varied from 18 to $47^{\circ}C$. For condensation test, mass flux and saturation temperature were varied from 86 to 128 kg/$m^2$s and 34 to $47^{\circ}C$, respectively. The equations of Gnielinski Soliman et al., Traviss et at., Cavallini and Zecchin, Shah, Chen et al., Tandon et al., and Chilli and Anand were compared with the experimental data. New correlations are proposed based on the experimental results and the absolute mean deviation of the experimental data becomes 1.0% for single phase test and 4.9% for condensation test.

• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
• /
• pp.426-427
• /
• 2006

Mono-sized silicon particles were effectively fabricated by a novel way named pulsated orifice ejection method (POEM). The particles are with very narrow particles size distribution and very small standard deviation of mean particle size. There are two different types spherical silicon particles were found. One consists of many grains mainly in random boundaries. The other consists of two or three grains with only twin orientation relationships, even single crystal in cross-section was also found within this type of spherical silicon particles.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2005년도 춘계학술대회 논문집
• /
• pp.262-265
• /
• 2005

A shape optimization of flow guide is accomplished to minimize the wear rate of die in three-dimensional flat-die extrusion processes. In order to achieve the balanced flow and the uniformed distribution of the effective strain during the extrusion, a multi-objective optimization is implemented. During the process of optimization formulation, the flow balance and the deviation of strain is considered as constrained conditions. The proposed approach is applied to an extrusion of H section. Through the optimization, it has been confirmed that the wear rate of die can be minimized satisfying the constraint.