• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.345-348
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• 2006

In sheet metal forming process using press and draw die some defect can be made because of the high pressure of air pocket between draw die and the product. The purpose of this study is to develop a program to decide an optimal combination of air vent hole size and number to prevent those defect on product. The air inside air pocket is considered as ideal gas and the compression and expansion is assumed as isentropic process. The mass flow is computed in two flow condition: unchocked and chocked condition. The present computation obtains required cross-sectional area of air vent hole for not exceeding the user specified pressure such as the pressure for yielding strength of the product or the pressure for unchocked flow. To validate the program the present results are compared with the results of other researchers and commercial CFD code.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.32-39
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• 1996

Hybrid decision decoding for the extended hamming codes without retransmission, which is a combination of hard and soft decision decoding, is proposed and its performance is analyzed in this paper. As results, hybsrid decision decoding shows a little bit higher residual bit error rate than soft decision decoding. However, as the size of the extended hamming code increases, the difference of th enumber of comparisons increases further. In addition, hybrid decision decoding shows almost same residual bit error rate as hard decision decoding with retrassmission and shows much lower residual bit error rate than hard decision decoding without retransmission.

• ETRI Journal
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• v.31 no.4
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• pp.393-398
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• 2009

The operation of a first-order 2-bit adaptive sigma-delta modulation system is described and discussed in this paper. The system operation is based on the combination of both "memory" and "look-ahead" estimation in the employed step-size adaptation algorithm of the basic quantizer. In comparison to simple systems and other adaptive sigma-delta systems, computer simulation results show that these features of the described system are responsible for the high SNR values and the extended dynamic range achieved for AC signals as well as the noise power reduction of almost 10 dB and the complete elimination of the idle tones for DC signals. However, such an advantageous performance requires the least possible multiplicative error accumulation, and this cannot be achieved without analog circuits of the highest possible accuracy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.313-318
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• 1996

This paper deals with the dynamic behavior of elastic columns under the action of subtangential forces. The above subtangential force can be-realized by the combination force between the dead load of thetip mass and the pure follower thrust. The tip mass is assumed to be a rigid body not a mass point as it has been assumed so for. The equations of motion are formulated based on extended Hamilton's principle and the finite element method. It is shown that nonconservativeness of the applied force has greatly effect on the instability type. It is found that the critical subtangential force can also be changed by consideration of the tip mass parameters taking into account of its magnitude, rotary inertia and size. The influence of the self-weight of the column on the change of the critical force is also investigated.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.1
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• pp.24-29
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• 2005

Optimal heat treatment process in martensitic stainless steel such as SUS416 is investigated. The approach is based on the combination of the interpolation and extrapolation method of a standard heat treatment technology with the principle of quenching and tempering temperature difference. The relationship of the macroscopic structure, fracture toughness and ductility as well as the hardness and strength are considered to induce a simple rule to apply with feasibility. Consequently, Optimal heat treatment condition in martensitic stainless steel is proposed and is shown the better quality. It was found that the smaller pain size of microstructure gives the enhanced fracture toughness and ductility.

• The International Journal of Costume Culture
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• v.6 no.2
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• pp.126-133
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• 2003

The purpose of this study was to develop the sizing system for men's glove. The combination of anthropometric and engineering aspects of glove pattern-making is difficult problem in engineering clothing. And the traditional measurements is not enough for glove. Therefore, to develop the hand measurement method and dimension for glove, a comprehensive list of candidate measurements was reviewed and the manufacturers (Their career was over the 15years) were interviewed on the method of glove pattern-making. This study was conducted traditional and creative 88 two-dimensional anthropometric measurements and 4 photometric measurements for glove pattern-making. In addition, 16 creative measurements were instrumented using a special hand measuring board for measuring of landmark locations on the hand. The subjects were 260 men's right hand in the age group of 18 to 35 years old in korea.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.1
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• pp.127-135
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• 2009

This paper presents a new technique for corner shape based object retrieval from a database. The proposed feature matrix consists of values obtained through a neighborhood operation of detected corners. This results in a significant small size feature matrix compared to the algorithms using color features and thus is computationally very efficient. The corners have been extracted by finding the intersections of the detected lines found using Hough transform. As the affine transformations preserve the co-linearity of points on a line and their intersection properties, the resulting corner features for image retrieval are robust to affine transformations. Furthermore, the corner features are invariant to noise. It is considered that the proposed algorithm will produce good results in combination with other algorithms in a way of incremental verification for similarity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.10
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• pp.553-558
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• 2009

Energy demand characteristics of hotel, hospital, and office building are compared to provide guidelines for combining building in community energy system design. The annual, monthly, and daily energy demand patterns for electricity, heating, hot water and cooling are qualitatively compared and important features are delineated based on the energy demand models. Key statistical values such as the mean, the maximum are also provided. Important features of the hourly demand patterns are summarized for weekdays and weekends. Substantial variations in both magnitudes and patterns are observed among the 3 building types and smart grouping or combination of building type and size is essential for a successive energy supply.

• Laser Solutions
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• v.2 no.3
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• pp.52-61
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• 1999

The laser induced forward transfer(LIFT) technique employs a pulsed laser to transfer parts of a thin metal film from an optically transparent target onto an arbitrary substrate in close proximity to the metal film on the target. In this work, a two-step method, the combination of LIFT process, in which a Au film deposited on the $Al_2$O$_3$ substrate by Nd:YAG laser and subsequent Au electroless metal plating on the by LIFT process generated Au seed, was presented. The influence of laser parameters, wavelength, laser power, film thickness and overlap ratio of pulse tracks, on the shapes of deposit and conductor line after electroless plating is experimentally studied. As a results, the threshold power densities for ablation, deposition and metallization were determined and comparison of threshold value between the wave length 1064nm and the second harmonic generated 532nm. In odor to determine a possible application in the electronic industry, a smallest conduct spot size, line width and isolated line space were generated.

• Journal of the Korean housing association
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• v.22 no.4
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• pp.63-70
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• 2011

This study was conducted to investigate the ambivalent characteristics of dichotomous contradictions expressed by Robert Venturi's architecture. It focused on his Mother's House, which applied his theoretical practices faithfully among many of his architectural works. First, he sought to change interior and exterior spaces by manipulating the architectural scales of "Mother's House". He achieved tension in space through structural complexities in combination with contradictions. Second, as for the characteristics of ambivalent contradictions, including linear and geometric forms, and plane, there were familarity which emphasizes tradition; external appearances of symmetry and asymmetry which give a comfort feeling; openness and closedness, which were expressed with the size of windows and objects such as molding. Third, the fireplace-chimney and the stair were forming appropriate harmony between contradiction and complexity as they competed for central position on the plane.