• 대한산업공학회지
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• 제9권2호
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• pp.27-35
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• 1983

This paper describes a procedure of generating economic cutter-location(CL) data for the machining of sculptured surfaces on a multi-axis NC milling machine. Measures of economy are the machining time (cutter move distance) and the length of NC tape (number of CL data points). The presented procedure minimizes both the number of CL data and the total distance of cutter moves, for a given cutter (spherical end-mill) size and parameteric cutting direction, while satisfying given tolerance requirements. The procedure has been implemented in FORTRAN for a smooth composite Bezier surface. The maximum allowable cutter size is calculated by the program so that a user can choose a cutter size. CL data can be generated in both parametric directions u and v. Experimental results show that there are significant differences between the parametric directions, and that cutter size should be as large as possible in order to minimize the cutting time and NC tape length.

• 제어로봇시스템학회논문지
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• 제10권11호
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• pp.1017-1021
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• 2004

In this paper, a cost-effective integrated 3D system for measuring and sizing foot is proposed. The proposed system employs two CCDs and a laser line projector which are capable of accurately measuring foot. The measurement is based upon the biologically motivated stereo vision principle providing ruggedness against minor system distortions. According to the tolerance, calibration between two different views are implicitly applied. Furthermore, the measurement system employs a measurement base, a frame grabber, a CCD moving cart, a stepping motor and computer. Analysis and design procedure is presented for the calculation of the 3D foot data and the proposed system. Experimental results on the proposed system would verify the concept and system operation.

• 품질경영학회지
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• 제34권3호
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• pp.66-72
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• 2006

The process capability indices are widely used to measure the capability of the process to manufacture items within the specified tolerance. Most evaluations on process capability indices focus on point estimates, which may result in unreliable assessments of process performance. The index $C_p$ has been widely used in various industries to assess process performance. In this paper, we propose new testing procedure on assessing $C_p$ index for practitioners to use in determining whether a given process is capable. The provided approach is easy to use and the decision making is more reliable. Whether a process is clearly normal or nonnormal, our bootstrap testing procedure could be applied effectively without the complexity of calculation. A numerical result based on the proposed approach is illustrated.

• 산업기술연구
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• 제5권
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• pp.65-71
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• 1985

In case that the datums chosen for dimension on engineering drawings are unsuitable for manufacturing and inspecting and inspection purposes and it is necessary to redimension the design from new datum. L. E. Farmer presented a theory for performing this change of datum, discussed a procedure for allocating tolerances to new dimensions and presented the procedure of change of datum as part of a computer aided design system. This paper deals with the development of the interactive computer program which is insufficiently presented without all coding list of program by L. E. Farmer.

• 한국정밀공학회지
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• 제19권4호
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• pp.79-86
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• 2002

As consumer electronics, information, and aero-space industry grow, the demand for aspheric lens increases higher. To enhance the precision and productivity of aspheric surface, a CAM system for ultra-precision aspheric surface needs to be realized. In this study, the developed CAM system can generate NC code fur various aspheric surfaces fast and precisely by a new bi-arc interpolation method that the location of maximum error is fixed at an efficient point. The newly developed bi-arc meets the given tolerance more precisely, performs faster calculation. The cutting condition input module and the NC code verification module are adequate to ultra-precision machining, so that a operator can obtain products fast and easily.

• 열처리공학회지
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• 제13권3호
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• pp.163-169
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• 2000

Recently, uncertainty of hardeness became a major concem for the people working on the laboratory evaluation and accreditation. It is required to indicate uncertainty of hardness tester on the report after calibration. In addition to this, uncertainty of certified hardness reference block is also required to indicate on the certification sheet. Method on the evaluation of uncertainty in hardness measurement is agreed only recently for Rockwell hardness C scale. In this paper, a preliminary calculation of uncertainty based on type B evaluation has been made for hardness testers which satisfies the requirements of Korean Standards. It was found that the tolerance limit of mean value specified in KS should be increased to be compatible with the calculated uncertainty.

• 설비공학논문집
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• 제3권1호
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• pp.11-25
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• 1991

The steady, incompressible developing 3-dimensional turblent flow in a square sectioned curved duct has been investigated by using partially-parabolic equation and Finite Analytic Method. The calculation of turbulent flow field is performed using 2-equation K-$\epsilon$ turbulence model, modified wall function, simpler algorithm and numerically generated body fitted coordinates. Iso-mean velocity contours at the various sections are compared with the existing experimental data and elliptic solutions by other authors. In the region of $0^{\circ}<{\theta}<71^{\circ}$, present results agree with the experimental data much better than the elliptic solution for the similar number of grid points. Furthermore, for the same tolerance, the present solution converges four times faster than the elliptic solution.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.217-222
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• 2005

Building energy consumption according to the ventilation has been considered to be an important subject. The purpose of this study is to investigate the cooling loads in a test space with a forced ventilating system. In the test space, on/off controlled air-conditioning and forced ventilating facility were operated between 8:30 to 21:00 during 4 days and some important data like temperatures and energy consumption were measured to obtain actual cooling loads. The simulation was carried out in a mode of temperature level control using a TRNSYS 15.3 with a precisely measured air change amount and performance data of air-conditioner. Cooling loads including sensible and latent were compared between by experiment and by simulation. Both of cooling loads associated with ventilation show a close agreement within an engineering tolerance.

• 한국세라믹학회지
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• 제38권12호
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• pp.1075-1079
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• 2001

The R-curve for in situ-toughened SiC-30 wt% TiC composites was estimated by the indentation-strength method and compared to that of monolithic SiC with toughened microstructure. Both materials exhibited rising R-curve behavior. The SiC-TiC composites, however, displayed better damage tolerance and higher resistance to crack growth. Total volume fractions of SiC key grains, which take part in toughening mechanisms such as crack bridging and crack deflection, were 0.607 for monolithic SiC ceramics and 0.614 for SiC-TiC composites. From the microstructural characterization and the residual stress calculation, it was inferred that this superior performance of SiC-TiC composites can be attributed to stress-induced microcracking at heterophase (SiC/TiC) boundaries and some contribution from carck deflection by TiC grains.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.290-292
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• 1994

This paper presents a methodology for the electric field analysis of substation. For the electric field analysis of substation, the electrodes(substation busbars) must be represented by finite line with nonlinear charge density. In the case of dividing finite line into uniform segments, a large number of variables have to be used to obtain the accuracy within a desired tolerance. To deal with the problem, nonuniform charge arrangement modeling method is suggested. To reduce potential calculation errors, the linear charge density function is considered particularly for the segment charge model ling. If the charge arrangement is improper, the accuracy not improved regardless of increment in the number of segments. This paper proposes an optimal charge arrangement method through potential error analysis. And, the optimal charge arrangement function is formulated by a lot of simulation results.