• 자동차안전학회지
• /
• 제9권4호
• /
• pp.38-47
• /
• 2017

With automobiles sharply increasing worldwide, we are faced with serious social problems such as traffic accidents, traffic jams, environmental pollution, and economic inefficiency. In response, research on ITS is promoted mainly by regions with advanced automotive industry such as the US, Europe, and Japan. While Korea is working to get ahead to take global market through developing and turning into global standards systems related to ASV(Advanced Safety Vehicle), the country is not excellently prepared for such projects. The purpose of ACC is to control the vehicle's longitudinal speed and distance and minimize driver workload. Such a system should be useful in preventing accidents, as it reduces driver workload in the 21st-century world of telematics created by the development of automobile culture industry. In this light, the thesis presents a method to test and evaluate ACC system and a mathematical method to assess distance. Furthermore, for the proposed test and evaluation, theoretical values are tested with vehicle test and a database is acquired, by using vehicles equipped with an ACC system. We proposed the scenarios suitable for the domestic environment and conducted the actual road test. Theoretical evaluation criteria for developing ACC system may be employed and scenario-specific evaluation methods may find their useful application through testing the formula proposed by comparing the database and the mathematical method. and, many companies are expected to utilize the scenario in the developing stage of ACC, and be able to employ as a verification method by harnessing theoretical formula before a road test.

• 한국산학기술학회논문지
• /
• 제12권12호
• /
• pp.5759-5765
• /
• 2011

본 연구의 목적은 간호대학생을 대상으로 심폐소생술 이론교육과 실습교육을 병행한 실험군과 이론교육만 받은 대조군 간의 교육 효과를 비교하여 향후 간호대학생의 심폐소생술 교육에 효과적인 방법을 적용하기 위한 기초자료를 제공하기 위함이다. 본 연구는 D시 소재 D대학 간호대학생 72명(실험군 36명, 대조군 36명)을 대상으로 하였으며, 자료수집은 2011년 8월 22일에서 8월 24일까지 이루어졌다. 수집된 자료는 SPSS WIN 18.0 Version 프로그램을 사용하여 실수, 백분율, $x^2$-test, t-test, paired t-test로 분석하였다. 연구결과 심폐소생술 교육은 간호대학생의 심폐소생술 수행능력과 자기효능감을 향상시켰으며, 특히 이론과 실습을 병행한 심폐소생술 교육이 더 효과적인 것으로 나타났다. 따라서 간호대학생의 심폐소생술 교육시 단순히 지식을 향상시키는데 초점을 맞추기 보다는 이론과 실습을 병행한 교육이 필요하며, 이는 간호대학생이 예측하지 못한 상황에서도 정확하고 신속한 심폐소생술을 수행하는데 도움을 줄 것이다.

• 한국지반신소재학회논문집
• /
• 제21권1호
• /
• pp.33-48
• /
• 2022

This paper presents illustrative examples of the application of advanced digital image correlation (DIC) technology in the geotechnical laboratory tests, such as shallow footing test, trapdoor test, retaining wall test, and wide width tensile test on geogrid. The theoretical background of the DIC technique is first introduced together with fundamental equations. Relevant reduced-scale model tests were then performed using standard sand while applying the DIC technique to capture the movement of target materials during tests. A number of different approaches were tried to obtain optimized images that allow efficient tracking of material speckles based on the DIC technique. In order to increase the trackability of soil particles, a mix of dyed and regular sand was used during the model tests while specially devised painted speckles were applied to the geogrid. A series of images taken during tests were automatically processed and analyzed using software named VIC-2D that automatically generates displacements and strains. The soil deformation field and associated failure patterns obtained from the DIC technique for each test were found to compare fairly well with the theoretical ones. Also shown is that the DIC technique can also general strains appropriate to the wide width tensile test on geogrid, It is demonstrated in this study that the advanced DIC technique can be effectively used in monitoring the deformation and strain field during a reduced-scale geotechnical model laboratory test.

• 한국해양공학회지
• /
• 제36권4호
• /
• pp.243-250
• /
• 2022

Subsea power cables are subjected to various external loads induced by environmental and mechanical factors during manufacturing, shipping, and installation. Therefore, the prediction of the structural strength is essential. In this study, experimental and theoretical analyses were performed to investigate the axial stiffness of subsea power cables. A uniaxial tensile test of a 6.5 m three-core AC inter-array subsea power cable was carried out using a 10 MN hydraulic actuator. In addition, the resultant force was measured as a function of displacement. The theoretical model proposed by Witz and Tan (1992) was used to numerically predict the axial stiffness of the specimen. The Newton-Raphson method was employed to solve the governing equation in the theoretical analysis. A comparison of the experimental and theoretical results for axial stiffness revealed satisfactory agreement. In addition, the predicted axial stiffness was linear notwithstanding the nonlinear geometry of the subsea power cable or the nonlinearity of the governing equation. The feasibility of both experimental and theoretical framework for predicting the axial stiffness of subsea power cables was validated. Nevertheless, the need for further numerical study using the finite element method to validate the framework is acknowledged.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2004년도 춘계학술발표회
• /
• pp.173-180
• /
• 2004

In this study, a consolidometer for radially inward drainage under constant rate of strain (CRS) loading was developed. Theoretical solutions for determining the effective vertical stress and the coefficient of consolidation from the test result were also proposed. Reconstituted kaolinite samples which were consolidated up to 130 kPa were used to verify the developed consolidometer and the theory. Comparative experiments with CRS loading and incremental loading (IL) were carried out in radially in ward drainage as well as vertical and radially outward drainage. The results obtained from the developed CRS loading test agreed consistently with those of the conventional incremental loading test according to drainage directions. And the effect of drainage direction and drain diameter to consolidation characteristics was also evaluated. From the test results the applicability and the reliability of the suggested method were verified.

• 대한기계학회논문집
• /
• 제5권4호
• /
• pp.347-353
• /
• 1981

The surging stresses of the valve spring of over head valve 4 cycle engine, which is made is Korea, were computed from theoretical analysis and these values were compared with the experimental results. For calculating surging stresses of test engine valve spring. Kato's equation should be corrected by the corretion factor C which is equal to twice rocker arm level ratio. Good agreement was found to exist between the theoretical analysis and the experimental results within.+-.5 percent differences. The stress amplitudes of test valve spring at each harmonic order were determined by the experiment and by using corrected equation, The safety considerations of test valve spring were discussed.

• 비파괴검사학회지
• /
• 제9권2호
• /
• pp.37-41
• /
• 1989

The purpose of this paper is to estimate the effect of wobble and nonconcentricity of tubes or rods in eddy current test with encircling test coils. Because the eddy current induced in a sample is related to the total magnetic flux linkages, the information about magnetic field distribution in a coil is important. In theoretical study, magnetic field distribution in a single turn coil was calculated and variation of impedance according to the difference of sample positions was presumed. Magnetic field intensity at inside of a solenoidal coil was measured and compared with the theoretical estimation. In experiment, impedance loci of a coil encircling an aluminum rod were measured at different sample positions. The effect of crack positions was examined at same sample positons.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
• /
• pp.902-907
• /
• 2003

Substantial experimental and theoretical work exists on the bond characteristics of FRP-concrete adhesive joints. Analytic solutions based on fracture mechanics are most commonly accepted for theoretical work on joint. The solutions may be derived for the simple form of the shear strees-slip curve. And it is difficult to determine the model parameters consisting the curve. In this study, the bilinear curve with softening branch is introduced. The model parameters are determined by the method described by the companion paper with comparison of test results. There are many uncertainties in the test results of CFRP sheet adhesive joints, so that test results used for the construction of the regression problem should be reasonably selected.

• 한국공작기계학회논문집
• /
• 제11권3호
• /
• pp.102-109
• /
• 2002

The fatigue crack growth under mixed mode condition has been discussed within the scope of linear fracture mechanics such as maximum tangential stress, maximum tangential principal stress and minimum strain energy density. The purpose of this study is to investigate the characteristics of fatigue test crack growth in 304 stainless steel under mixed node. The fatigue test results carried out by using inclined pre-crack specimens was compared to both of the theoretical predictions of the criteria, maximum tangential stress and stain energy density. As difference from theoretical analysis, the transition region from mixed mode to mode I appeared in the fatigue test. There is deep relationship between the angle of slanted pre-crack and transition. Therefore, as applying the different stress intensity factor to each node I+II and mode I, the directions and rates of fatigue crack growth are evaluated more accurately under mixed mode.

• 한국소음진동공학회논문집
• /
• 제14권8호
• /
• pp.675-683
• /
• 2004

The motor current signature provides an important source of the information for the faults diagnosis of three-phase induction motor. The theoretical principles behind the generation of unique signal characteristics, which are indicative of failure mechanisms, are Presented. The fault detection techniques that can be used to diagnose mechanical Problems, stator and rotor winding failure mechanisms, and air-gap eccentricity are described. A theoretical analysis is presented which predicts the presence of unique signature patterns in the current that are only characteristics of the fault. The predictions are verified by experimental results from a special fault Producing test rig and on-site tests in a steel company. And this study have made new diagnostic algorithm for the operating induction motors with the test results. These developments are including the use of monitoring and analysis of electric current to diagnose mechanical and electrical problems and gave the precise test results automatically.