• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.847-848
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• 2009

• 한국정밀공학회지
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• 제27권9호
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• pp.103-110
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• 2010

This paper presents the optimized approximation of finite element modeling for a complex tool holder spindle using both DOE (Design of Experiment) with Optimal Latin Hypercube (OLH) method and approximation modeling method with Radial Basis Function (RBF) neural network structure. The complex tool holder is used for holding a (milling/drilling) tool of a machine tool. The engineering problem of complex tool holder results from the twisting of spindle of tool holder. For this purpose, we present the optimized approximation of finite element modeling for a complex tool holder spindle using both DOE (Design of Experiment) with Optimal Latin Hypercube (OLH) method (specifically a module of $iSight^{(R)}$ FD-3.1) and approximation modeling method with Radial Basis Function (RBF) (another module of $iSight^{(R)}$ FD-3.1) neural network structure

• International Journal of Fluid Machinery and Systems
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• 제8권3호
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• pp.124-131
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• 2015

The good performance of a vortex shedder is defined by strong and stable vortex generated under the condition of most linearity in Strouhal number and low power loss. In this paper, the flow past a bluff body of circular cylinder with a slit normal to the flow has been analyzed focusing on drag coefficient, linearity of Strouhal number and flow resistance (K-factor). The ANSYS/FLUENT package is used for flow simulation and the integration method of computational code to iSIGHT platform is employed for automated design cycle. This study results the design with (0.20~0.267) blockage ratio and 0.10 slit ratio as the best shedder for vortex flowmeter and this results are in well agreement with the experiment. As the combination of GAMBIT, FLUENT, and iSIGHT substitutes the design parameters automatically according to the input data, this method designs effectively the vortex shedder with less design cycle time and low manufacturing cost eliminating the human intervention bottleneck.

• 한국공작기계학회논문집
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• 제18권1호
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• pp.110-115
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• 2009

In general, the radial error motion of a machine tool spindle system is effected on the accuracy of the parts to be made. This paper presents in milling process an investigation into spindle rotational accuracy effects on surface roughness of processing parts. We experimented the effects on spindle rotational accuracy in milling process by cutting AL 7075 workpiece at various rotational speed. In order to analyze the effects of rotational accuracy on surface roughness, we proposed the method using iSIGHT's RBF Approximation. The proposed method can be used fur anticipating the surface roughness when some spindle rotational accuracy experiments could be done in milling process.

• 대한교통학회지
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• 제26권3호
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• pp.187-197
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• 2008

운전자는 도로를 주행하는 동안 도로의 기하구조 및 교통상황, 신호등, 표지판 등을 통하여 많은 정보를 얻게 되고, 이에 따라 가감속도 및 주행방향 등을 결정하게 되는데 대부분의 정보를 운전자의 시각을 통하여 구득하게 된다. 따라서 도로 주행 시 운전자의 시거확보는 안전한 도로 주행을 위하여 반드시 필요하다. 그러나 현행 기하구조 및 시거 설계지침에서는 평면선형과 종단선형을 분리하여 기준을 제시하고 있으며, 복합선형에 관한 정량적인 설계기준은 제시되어 있지 않다. 현재 2차원적 투영면에 분리된 요소로 설계되어지고 있지만 실제 도로는 3차원적인 문제이기 때문에 2차원적 설계는 안전하고 쾌적한 설계를 보장해주지 못한다. 본 연구에서는 수학적인 계산을 통하여 입체시거를 분석한 기존의 모형을 이용하여 여러 가지 기하구조 요소 및 유형별로 분류한 후 기존의 2차원시거와 3차원시거를 비교하고 분석하여, 2차원시거에 비해 3차원시거가 얼마나 과대 또는 과소평가 되어지는 지를 알아보고, 지방부 2차로 도로 곡선부의 주행속도를 예측하는 모형을 개발하여 예측된 주행속도로 주행할 때 필요한 정지시거와 3차원시거를 비교하여 도로의 일관성을 평가하는 방법을 제시하고자 한다.

• 한국항해학회지
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• 제8권2호
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• pp.1-13
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• 1984

This paper concerns computerization of the altitude correction in the sight reduction process. To obtain observed altitude, the factors such as refraction, parallx, semidiameter, phase etc, are corrected to sextant altitude. The factors are the arguments into the nautical almanac table from which are extracted values to add to or substract from the raw sight to obtain corrected value. If the altitude correction is to be done by sophisticated calculator, each factors must be formulated. The author studies the formulation of above factors, and simply from the date and ephemeris time of the sighting calculate the values of the factors. The calculated values are compared with that from nautical almanac, and it is confirmed that the formulae are practically used.

• International Journal of Fluid Machinery and Systems
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• 제9권2호
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• pp.150-158
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• 2016

In this paper, a new framework that works the automatic execution with less design cycle time and human intervention bottlenecks is introduced to optimize the vortex shedder design by numerical integration method. This framework is based on iSIGHT combined with the pre-processor GAMBIT, and flow analysis software FLUENT. Two vortex shedders, circular with slit and triangular- semi circular cylinder, are employed as the designed models to be optimized, and DOE driver is used for optimization. According to the essential properties of a vortex shedder, it has found that the best diameters are 30mm for circular cylinder with slit and 30 to 35 mm for tri-semi cylinder. For slit ratio, 0.1 and 0.15 are the optimized values for circular with slit and tri-semi cylinder respectively. And it is found that these optimal results generated by DOE automated design cycle are in well agreement with the experiment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.655-660
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• 2004

The pipes in the outdoor unit of an air conditioner are designed to reduce the vibration effect of the compressor. Three-dimensional structure of the pipe could provide various design choices and the resultant vibration characteristics of the outdoor units. A design program has been developed for an eligible parametric study of pipe design and automatic vibration analysis using commercial software, I-DEAS, and its macro. Optimal design of pipe configuration has been performed using the commercial software, iSIGHT. The optimized design shows 70 percents improvement in the vibration characteristics of the outdoor unit of an air conditioner.

• 천문학회보
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• 제43권2호
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• pp.43.2-43.2
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• 2018

The line-of-sight component in the relative motion of galaxy pairs sources the redshift space distortion (RSD) in galaxy surveys. By knowing the probability density function (PDF) of pair-wise motions and projecting it to the line-of-sight direction, one can compute the RSD effect precisely. I present the pair-velocity PDF of dark matter and galaxies in the Horizon-run 4 simulation. I also derive a model motivated by the perturbation theory which fits the results fairly well. I also discuss the application of the model in constraining the cosmology.

• 대한가정학회지
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• 제35권1호
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• pp.307-318
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• 1997

The purpose of this study is to survey differences of visual effects for location the york line. According to three types of body shapes(average, small & thin small & fat)for location of the york line We investigated the visual effects and optical illusion by slider and the results of data which analized by anova and duncan's multiple rannge are as follows. 1. In the A.V (average) body shapes design D1 was showed D1 was showed to be most remarkable in terms of optical illusion and design D2 was showed to be prefer in terms of visual sight. 2. In the S.T(small& thin) body shapes design D1 was showed to be most remarkable in terms of optical illusion but from the side view of looking thinness design D4 was showed to be nogative and from preference of visual sight design D4 was showed to be most negative. 3. In the S.F(small& fot) body shapes design D1 was showed to be most remarkable in terms of optical illusion and design D3 gained the bettle of superiority from the side view of looking tallness and design D3 was showed to be most negative in terms of the preference of visual sight.