• Journal of the Korean Institute of Intelligent Systems
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• v.8 no.4
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• pp.1-7
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• 1998

This paper describes a meshless of element-free method based on fuzzy knowledge processing. To efficiently simulate complicated physical phenomena with dynmics and non-linear ploblem using computational mechanics, special method is required such as parallel processing or adaptive analysis techniques. However, the conventional finite element method is too complicated to be employed in the above cases. In order to reduce the above complexity of the conventional finite element analysis systms, the so called meshles finite elements as an input information have been stuided. Node is generated if its distance form existing node points is similar to the node spacing fuction at the point. The node spacing function is well controlled by the fuzzy knowledge processing Practical performances of the present system are demonstrated through several three-dimensional(3D) problems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1109-1114
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• 2007

When unifying the functions of widely used two-fan, engine cooling system into a single unit, the noise and power issues must be addressed. The noise problem due to the increased fan radius is a serious matter especially as the cabin noise becomes quieter for sedans. Of the fan noise components, discrete noise at BPF's (Blade Passing Frequency) seriously degrades cabin sound quality. Unevenly spaced fan is developed to reduce the tones. The fan blades are spaced such that the center of mass is placed exactly on the fan axis to minimize fan vibration. The resulting fan noise is $3{\sim}11$ dBA quieter in discrete noise level than the even bladed fan.

• Journal of the Mineralogical Society of Korea
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• v.12 no.1
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• pp.23-31
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• 1999

The dehydroxylation of kaolinite was investigated in detail by means of energy-filtering transmission electron microscope with both orientations parallel and perpendicular to c. The dehydroxylation could be characterized by the broad background including (0.211) band (20~24$^{\circ}$ 2$\theta$) on X-ray diffraction and by the three halo rings (d-spacing : 3.28~4.40$\AA$ (near (02,11) band), 2.41~245$\AA$ (near (20,13) band), 1.16~1.23$\AA$ (near (0.8,44) band)), and (02,11) and (20,13) spots on electron diffraction. These indicate existence of a short-range order along the a and b axes. Interplanar spacing of (001) is reduced to about 6.86$\AA$ and the sharp additional intensity maximum of about 14.2$\AA$ reveals that metakaolinite has a modulated structure along c axis. It is proposed that the modulated structure is attributed to the domains consisting of more than two-layers due to the changes of positions of the vacant octahedral sites in successive layers.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.6 no.2
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• pp.144-149
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• 2006

This paper describes a novel automated analysis system for bellows of piping system. An automatic finite element (FE) mesh generation technique, which is based on the fuzzy theory and computational geometry technique, is incorporated into the system, together with one of commercial FE analysis codes and one of commercial solid modelers. In this system, a geometric model, i.e. an analysis model, is first defined using a commercial solid modelers for 3-D shell structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay triangulation technique is introduced as a basic tool for element generation. The triangular elements are converted to quadrilateral elements. Practical performances of the present system are demonstrated through several analysis for bellows of piping system.

• Journal of the Korean Society for Heat Treatment
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• v.28 no.2
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• pp.82-86
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• 2015

In this study, the temperature gradient of a floating zone (FZ) apparatus, which is very difficult to directly measure, could be estimated by using the relationships between the lamellar spacing of directionally solidified TiAl alloys and the solidification rate, It was found that the calculated temperature gradient of the FZ apparatus was much higher, and almost ten times higher than that of a Bridgman type directional solidification apparatus.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.679-684
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• 1997

In this study, compressive strengths of reinforced concrete compression members rehabilitated with C.F.L. were analyzed from the test. Test parameters are spacing, spliced length, and section area of rehabilitation material. Displacement, failure load were measured during test. The failure mode and ultimate load were analyzed from these measured data. Test result shows that closer spacing of C.F.L. is more effective. strengthening with 1-ply C.F.L. is more effective than that of specimen with 2-ply C.F.L. The compressive capacity of specimen spliced ($\pi$.D)/2 shows almost similar strength to that of non-spliced specimen. The ultimate load carrying capacity of specimen strengthened with C.F.L. is increased to 1.11~1.68 times of that of non-rehabilitation specimen.

• Transactions of Materials Processing
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• v.18 no.3
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• pp.262-267
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• 2009

Selective laser sintering is a kind of rapid prototyping process whereby a three-dimensional part is built layer wise by laser scanning the powder. This process is highly influenced by powder and laser parameters such as laser power, scan rate, fill spacing and layer thickness. Therefore a study on fabricating Fe-Ni-Cr powder by selective laser sintering has been performed. In this study, fabrication was performed by experimental facilities consisting of a 200W fiber laser which can be focused to 0.08mm and atmospheric chamber which can control atmospheric pressure with argon. With power increase or energy density decrease, line width was decreased and line surface quality was improved with energy density increase. Surface quality of quadrangle structure was improved with fill spacing optimization.

• Structural Engineering and Mechanics
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• v.9 no.6
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• pp.589-600
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• 2000

This paper attempts to provide a theoretical basis for the design of high-strength concrete columns in terms of the spacing of lateral reinforcement. In order to achieve this, important concepts had to be addressed such as the choice of a measure of ductile behaviour and a realistic high-strength concrete stress-strain model, as well as limiting factors such as longitudinal steel buckling and lateral steel fracture. A design method incorporating above factors are suggested in the paper. It is shown that both buckling of longitudinal steel and hoop fracture will not demand a reduction in spacing of lateral ties with increase in compressive strength of concrete.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.6 no.1
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• pp.58-63
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• 2006

This paper describes a novel automated analysis system for bellows of piping system. An automatic finite element (FE) mesh generation technique, which is based on the fuzzy theory and computational geometry technique, is incorporated into the system, together with one of commercial FE analysis codes and one of commercial solid modelers. In this system, a geometric model, i.e. an analysis model, is first defined using a commercial solid modelers for 3-D shell structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay triangulation technique is introduced as a basic tool for element generation. The triangular elements are converted to quadrilateral elements. Practical performances of the present system are demonstrated through several analysis for bellows of piping system.

• ETRI Journal
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• v.34 no.3
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• pp.319-329
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• 2012

Closed-loop transmit diversity is considered an important technique for improving the link budget in the third generation and future wireless communication standards. This paper proposes several transmit diversity algorithms suitable for small wireless terminals and presents performance assessment in terms of average signal-to-noise ratio (SNR) and outage improvement, convergence, and complexity of operations. The algorithms presented herein are verified using data from measured indoor channels with variable antenna spacing and the results explained using measured radiation patterns for a two-element array. It is shown that for a two-element array, the best among the proposed techniques provides SNR improvement of about 3 dB in a tightly spaced array (inter-element spacing of 0.1 wavelength at 2 GHz) typical of small wireless devices. Additionally, these techniques are shown to perform significantly better than a single antenna device in an indoor channel considering realistic values of latency and propagation errors.