• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2005년도 연구개발 발표회 논문집
• /
• pp.441-447
• /
• 2005

The present study is aimed at understanding the flow physics associated with a safety valve applied to LNG ship engines. One-dimensional gasdynamic analyses and axisymmetric, compressible Navier-Stokes computations have been carried out to provide a qualitative and quantitative knowledge base for an effective design of the safety valve. Gasdynamic forces and thrust coefficients are obtained regarding a change in chamber pressure and distance between the nozzle exit and valve sheet which are major parameters to offer a variation in the flow feature. The present results show that the control of the passage area between the nozzle exit and valve sheet can attenuate the strength of shockwave generated in front of the valve sheet, which causes harm to stable system operation.

• 한국응용과학기술학회지
• /
• 제27권2호
• /
• pp.144-151
• /
• 2010

Over the years, scientists have developed many test methods to evaluate the efficacy of skin care products. The needs for objective assessment have stimulated to develop instruments that are capable of reliably monitoring some parameters in evaluating skin conditions. The beauty is evaluated as a measure of smoothness of skin surface. Quantitative size measurements of skin pores is also important concept to evaluate the their conditions. The purpose of this paper is to measure the temperature change of skin and the size of pores in the skin. The pore sizes were changed by its varying skin temperature. They were decreased by applying a essence which is contained with propellant and contents.

• 말소리와 음성과학
• /
• 제8권1호
• /
• pp.1-7
• /
• 2016

The purpose of this study is to know the acoustic characteristics of voice under stressful and relaxed conditions. Ten undergraduate male students participated in this study and produced 아, 에, 이 vowels in English reading, difficult Korean reading under stressful conditions, and easy Korean reading under relaxed conditions. After that, F0, jitter, shimmer, NHR, F1, F2, and F3 values were measured and analyzed. The results of this study demonstrate that speech parameters related to stress are jitter, shimmer, and NHR in that these values are lower under relaxed situations (easy Korean reading) than that of stressful situations (English and difficult Korean reading). This study will be a foundation to verify that the analysis of acoustic characteristics can serve as a quantitative tool for measuring stress levels.

• Communications for Statistical Applications and Methods
• /
• 제2권2호
• /
• pp.176-183
• /
• 1995

Mean opinion score (MOS) method has been used in many areas to quantify opinions of respondents not only in survey research but in evaluating the parameters of population that are not measurable of are technically hard to be measured. Histogram is an important graphical technique because of the role it plays in describing categorical data as well as quantitative. In MOS method, subjective opinions of respondents are quantified by opinion scores and the arithmetic means of opinion scores have been used to describe the interesting population. Since opinion scores are polytomous, the values of arithmetic means have little meanings. In this paper, cumulative percentage curves as a function of the means of opinion scores are derived by combining means of opinion scores and histograms. It is proposed for better interpretation to opinion scores in MOS method, one of subjective evaluation methods.

• 소성∙가공
• /
• 제20권6호
• /
• pp.456-460
• /
• 2011

A major source of difficulty in die design for high strength steel is the high level of elastic recovery during unloading. The degree of elastic recovery is affected by factors such as material strength, bending angle, punch's corner radius and sheet thickness. Finite Element Method was used in the present work to quantitatively analyze the elastic recovery for various combinations of these parameters. In some cases elastic recovery happened in reverse direction. This phenomenon, which we call spring-go, was explained via changes in stress distribution in the panel occurring in the forming process.

• Journal of the Korean Wood Science and Technology
• /
• 제24권2호
• /
• pp.1-6
• /
• 1996

This study was performed to investigate the feasibility of using sonic stress-wave technique in the longitudinal direction for the assessment of incipient decay of radiata pine wood. Decayed bending specimens by Tyromyces palustris and Gloeophyllum trabeum for varoious periods were tested nondestructively using stress-wave technique in the longitudinal direction and destructively. Decay detection, quantitative assessment of decay, and the prediction of residual strength of decayed wood with less than five percent weight loss can be feasible using stress-wave parameters (wave velocity, wave impedance, stress-wave elasticity) measured by stress-wave technique in the longitudinal direction and their percent reduction due to decay.

• 한국소음진동공학회논문집
• /
• 제16권4호
• /
• pp.339-345
• /
• 2006

In this paper, a physically meaningful methodology which can assess the contribution of each vibration mode to various vibration response signals (displacement, velocity, acceleration) is developed. Based on these results, the problem of quantitative assessment of the relative importance of a structural system's vibrational modes is discussed. In addition, a direct method which ran assess the relative importance of each mode from uniformly sampled experimental data is also proposed.

• 자원환경지질
• /
• 제24권1호
• /
• pp.71-79
• /
• 1991

Anisotropy of magnetic susceptibility (AMS), directional variation of susceptibility in a sample, indicates the relative magnitude and orientation of preferentially aligned magnetic grains in a rock sample and represents important aspects of rock fabrics. This observation leads to various studies which applied the AMS technique to numerous geological problems, especially sedimentology, petrology, structural geology, and tectonics. Since AMS is, relative to conventional methods of petrofabric measurement, quickly measured, easily interpretated, and providing quantitative data, AMS technique has evolved into a powerful tool for detection of rock fabrics and continues to draw the interest of non-specialists as well as magnetists. This paper represents the theory, techniques, and parameters of the relatively new AMS method for estimating petrofabrics and their various applications.

• 대한의용생체공학회:의공학회지
• /
• 제12권4호
• /
• pp.249-254
• /
• 1991

In the study on the quantitative diagnosis using ultrasound, the stability and precision of tissue characterized parameters are important for the clinical application. We estimate attenuation coefficient introducing homomorphlc process Into the modified spectral differnce method about silicon-madu phantom. We compare the results with those estimated uslng the method used for obtaining the attenuation map image before. Homomorphic process has the effect smoothing the reflected echo signal spectrum, therefore eliminat os the random pattern of the signal spectrum generated by the scatterers. As a result, it Is shown that the stability is enhanced

• 한국초전도저온공학회:학술대회논문집
• /
• 한국초전도저온공학회 2003년도 학술대회 논문집
• /
• pp.28-32
• /
• 2003

Miniature inertance pulse tube refrigerator was designed and fabricated to provide optimal performance with 10W compressor. An adiabatic model was used to design an inertance pulse tube refrigerator. Among the various design parameters which should be optimized, pulse tube length and inertance tube length were considered. PdV work and various losses were calculated for various pulse tube and inertance tube length. Experiments were carried out for different pulse tube length and inertance tube length. It was shown that the experimental results were similar to the calculated results. The reason why the quantitative optimal point exists is explained.