• KSTLE International Journal
• /
• 제6권1호
• /
• pp.21-27
• /
• 2005

A technique for a wear volume calculation is improved and verified in this research. The wear profile data measured by a surface roughness tester is used. The present technique uses a data flattening, the FFT and the windowing procedure, which is used for a general signal processing. The measured value of an average roughness of an unworn surfnce is used for the baseline of the integration for the volume calculation. The improvements from the previous technique are the procedures of the data flattening and the determination of a baseline. It is found that the flattening procedure efnciently manipulates the raw data when the levels of it are not horizontal, which enables us to calculate the volume reasonably well and readily. By comparing it with the weight loss method by using artificial dents, the present method reveals more volume by aroung 3~10%. It is attributed to the protruded region of the specimen and the inaccuracy and data averaging during the weght loss measurement. From a thorough investigation, it is concluded that the present technique can provide an accurate wear volume.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2006년도 PARALLEL CFD 2006
• /
• pp.63-65
• /
• 2006

• Journal of Electrical Engineering and Technology
• /
• 제8권4호
• /
• pp.872-878
• /
• 2013

In industrial control systems, flow measurement is a very important issue. It is frequently needed to calculate how much total fluid or gas flows through a cross-section. Flow volume measurement tools use simple sampling or rectangle methods. Actually, flow volume measurement process is an integration process. For this reason, measurement systems using instantaneous sampling technique cause considerably high errors. In order to make more accurate flow measurement, numerical integration methods should be used. Literally, for numerical integration method, Rectangular, Trapezoidal, Simpson, Romberg and Gaussian Quadrature methods are suggested. Among these methods, trapezoidal rule method is quite easy to calculate and is notably more accurate and contains no restrictive conditions. Therefore, it is especially convenient for the portable flow volume measurement systems. In this study, the volume measurement of air which is flowing through a cross-section is achieved by using PLC ladder diagram. The measurements are done using two different approaches. Trapezoidal rule method is proposed to measure the flow sensor signal to minimize measurement errors due to the classical sampling method as a different approach. It is concluded that the trapezoidal rule method is more effective than the classical sampling.

• The Journal of Asian Finance, Economics and Business
• /
• 제4권1호
• /
• pp.51-58
• /
• 2017

The aim of the study is to assess the asymmetry of influence of factors of economic growth of national economies, which are included in the integration. Unlike previous research, the scientific significance of the obtained results consists in the use of a new method of study - external demand as a factor of economic growth, disaggregated into two components. The first is net exports mutual trade in goods within integration associations. The second is net exports of foreign trade in goods outside the integration. By use of these methods we have evaluated the contribution of these factors on economic growth of the Customs Union and the Common Economic Space (CU/CES), as well as Kazakhstan, Russia and Belarus. In the conducted analysis of scientific research was based on the fact that the economies of the member (CU/CES) are very different in scale, economic potential and volume of foreign trade. Based on this research we conclude: integration is developing successfully and efficiently only with the rise of the national economies of the member countries; to enhance economic growth and competitiveness of the countries of the Eurasian integration it is necessary to increase the volume of mutual trade of member countries of this integration.

• Tribology and Lubricants
• /
• 제17권1호
• /
• pp.33-39
• /
• 2001

A method of calculating wear volume is developed using the signal processing technique. The lowpass filter with Fourier transform and the “windowing” are implemented in the method. User-defining feature is also included in determining the cutoff frequency of the low-pass filter and the baseline for the volume integration. Commercial software, MatLab, is used for the programming. Since the method uses the original wear data without simplifying the wear shape, it can give a further accurate result than the previously utilized methods, which often adopted the simplification. It becomes further powerful if the contacting body has a general shape rather than that gives well-formed surface traction (e.g., the Hertzian). The validation of applying the average surface roughness, Ra, to the “windowing” and the baseline for volume integration is discussed.

• Journal of Advanced Marine Engineering and Technology
• /
• 제32권8호
• /
• pp.1215-1220
• /
• 2008

To obtain the shape of the free surface more accurately, computations are carried out by a finite volume method using unstructured meshes and an interface capturing method. Free-surface flow, which is very important in the fields of ship and marine engineering, is numerically simulated for flows of both water and air. Control volumes are used with an arbitrary number of faces and allows a local mesh refinement. The integration is of second order, with a midpoint rule integration and linear interpolation. The method is fully implicit and uses quadratic interpolation. The solution method of pressure-correction type solves sequentially equations of momentum, continuity, conservation, and two-equations turbulence model. Comparison are quantitatively made between the computation and experiment in order to confirm the solution method.

• 한국전산유체공학회지
• /
• 제9권2호
• /
• pp.43-51
• /
• 2004

Interaction between fluid flow and thermal radiation has received considerable attention due to its numerous applications in engineering field. In this case the thermofluid properties of radiating fluid vary with the variation of temperature field caused by absorption and emission of radiant heat. To analyze the radiation heat transfer in radiating fluid, the simultaneous solution of the radiative transfer equation (RTE) and the fluid dynamics equations is required. This means that the numerical procedure used for the RTE must be computationally efficient to permit its inclusion in the other submodels, and must be compatible with the other transport equations. The finite volume method (FVM) and the discrete ordinates method (DOM) are usually employed to simulate radiation problems in generalized coordinates. These two representative methods are examined and compared, especially in view of the numerical integration of the radiation intensity over solid angle. The FVM shows better accuracy than the DOM owing to less constraints of the selection of control angle.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2004년도 춘계 학술대회논문집
• /
• pp.62-70
• /
• 2004

Interaction between fluid flow and thermal radiation has received considerable attention due to its numerous applications in engineering field. In this case the thermofluid properties of radiating fluid vary with the variation of temperature field caused by absorption and emission of radiant heat. To analyze the radiation heat transfer in radiating fluid, the simultaneous solution of the radiative transfer equation (RTE) and the fluid dynamics equations is required. This means that the numerical procedure used for the RTE must be computationally efficient to permit its inclusion in the other submodels, and must be compatible with the other transport equations. The finite volume method (FVM) and the discrete ordinates method (DOM) are usually employed to simulate radiation problems in generalized coordinates. These two representative methods are examined and compared, especially in view of the numerical integration of the radiation intensity over solid angle. The FVM shows better accuracy than the DOM owing to less constraints of the selection of control angle.

• 한국수학교육학회지시리즈E:수학교육논문집
• /
• 제26권2호
• /
• pp.155-176
• /
• 2012

미분적분학에서 정적분의 수치계산법에 대한 팀프로젝트(Team Project) 문제를 제시한다. 제시한 팀프로젝트 문제는 흉부 CT 사진을 통해서 폐의 부피를 구하는 것으로 특별히 의학을 공부하는 학생들에게 흥미를 유발할 수 있는 전문화 및 특성화된 미분적분학(정적분의 수치계산법) 수업이 될 것이다. 또한 프로젝트 해결 과정에서 다양한 테크놀로지(MATLAB, MATHEMATICA, MS-Excel)를 도입한다.

• 한국시뮬레이션학회논문지
• /
• 제15권1호
• /
• pp.19-25
• /
• 2006

도시지역이 급격히 확장됨에 따라, 인구 및 교통량이 증가되어 교통 혼잡이 큰 사회문제가 되고 있다. 일반적으로 다인승전용차로는 도로의 이용효율을 증대시킬 수 있는 방안으로 알려져 있으며, 도시부 교통문제 해소의 한 방안이다. 본 논문에서는 서울의 중심 도시고속도로인 올림픽대로의 교통 혼잡을 완화하기 위한 방안으로 다인승전용차로제의 도입 가능성을 시뮬레이션 툴인 Integration을 이용하여 과학적으로 분석 평가하였으며, 향후 이러한 분석기법이 다인승 전용차로제 도입 가능성 평가에 많이 사용될 수 있을 것이다.