• 제어로봇시스템학회논문지
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• 제17권11호
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• pp.1101-1105
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• 2011

Radiation particles can introduce temporary errors in memory systems. To protect against these errors, so-called soft errors, error detection and correcting codes are used. In addition, scrubbing is applied which is a fundamental technique to avoid the accumulation of soft errors. This paper introduces an optimal scrubbing scheme, which is suitable for a system with auto error detection and correction logic. An auto error detection and correction logic can correct soft errors without CPU's writing operation. The proposed scrubbing scheme leads to maximum reliability by considering both allowable scrubbing load and the periodic accesses to memory by the tasks running in the system.

• 한국CDE학회논문집
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• 제1권3호
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• pp.215-223
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• 1996

Every mechanical part is fabricated with the variations in its size and shape, and the allowable range of the variation is specified by the tolerance in the design stage. Geometric tolerances specify the size or the thickness of each shape entity itself or its relative position and orientation with respect to datums while considering their order of precedence. It would be desirable if the assemblability of parts could be verified in the computer when the tolerances on the parts are store together with the geometric model of the parts of an assembly and their assembled state. Therefore, a new method is proposed to represent geometric tolerances and to determine the assemblability. This method determines the assemblability by subdividing the ranges of relative motion between parts until there exists the subdivided regions that do not cause the interference.

• 한국정밀공학회지
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• 제27권11호
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• pp.84-91
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• 2010

Heat treatment with carburized quenching process is widely used for automotive helical gear to improve its surface properties of hardness and strength. However, the gear can be deformed with the process over the allowable tolerance, which possibly makes noise, vibration and heat problems in operation. In this study, deformation of helical gear during heat treatment of carburized quenching was analyzed with a numerical method, incorporating coupled calculations of thermal conduction, carbon diffusion, phase transformation and thermal stresses. With the analysis, the effect of coolant temperature in quenching on the deformation was investigated. The result of the analysis revealed that the higher the coolant temperature became, the more change of helix angle and the more compressive stresses in the surface generated, because of delayed generation of martensite in the part.

• 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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.735-736
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• 2008

There are many equipments for the Short Circuit Test, for example Short Circuit Generator, Induction Motor, Sequence Timer, CLR, Back Up Breaker, Making Switch and Excitation Equipment etc. Gradually an allowable tolerance of the short circuit test voltage is become smaller by the standards for short circuit test. The excitation equipment of short circuit generator is very important for test voltage is adjusted by the excitation equipment. Especially the excitation equipment must be possessed character of exactitude, durability and inalterability because some times around 10,000 times opening and closing short circuit test is requested by clint, which must be done within one minute. The purpose of this study for function and operation of the excitation equipment which rated DC voltage is 1,000V, rated DC current is 300A, rated out put is 30kW and type is YNEX 97S-441/609, is to help operation of short circuit generator.

• 소성∙가공
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• 제17권8호
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• pp.649-656
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• 2008

Springback is one of factors affecting precision in metal forming. Its effect is particularly prominent in bending process. In this study, bending and forging process are used in order to manufacture a micro spring with two bending region from $60{\mu}m$ diameter wire. Springback in the process lowers the precision of the micro spring. Overbending for springback compensation has wide usage in a general way. However, this method requires repeated modifications of press dies until the tolerance is allowable, which causes that production cost and time increase. In this paper, we analyzed the mechanism of springback in the forming process of the micro spring using finite element method. In addition, a simple method to control springback without modifying dies was proposed by performing numerical analysis with various parameters.

• 한국산업융합학회 논문집
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• 제8권3호
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• pp.161-168
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• 2005

This study is analysis for adjacent structures and ground movement by deep excavation work. Underground Inclinometer has shown that deformation of increment is minor within to allowable limit. According to the measurements result of slope and crack for adjacent structures, a detached house showed bigger than hospital structure to deformation of increment. Variation of underground water level didn't effect so much to ground and adjacent structures movement because underground water flows in rock and didn't give the water press to propped walls. Measurement data of strut variation is within tolerance limit. Because excavation site's wall was strengthened suitably. This study will contribute in establishment of measurement standard and information-oriented construction during deep excavation in multi-layered ground including rock masses.

• 한국안전학회지
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• 제17권4호
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• pp.1-4
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• 2002

A automatic production system was developed for high productivity and safety. The semi-progressive die was unfavorable for more productivity, safety, material extravagance and incongruent high-speed production. Developed progressive die is suitable for the high production and guarantee triple production by acceptance of three array type for automobile adjust plate. We adopt Pro-$Engineer{\circledr}$ for three dimensional computer aided design suitable for the disassembly and assembly evaluation. The conclusion of this study is as follow. First, press die parts solid modeling system is built by using Pro-$Engineer{\circledr}$ through this research and verified allowable tolerance and possibility of assembly and disassembly of parts. Therefore we can reduce die manufacturing time and cost. Second, We produce 1000 units pet hot coil 1ton by traditional method, but we can acomplish material saving effect about 12% as 120 units in case of new progressive die. Fourth, we acomplished manufacturing cost curtailment effect more than 20% in comparison with traditional method.

• 한국산업융합학회 논문집
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• 제22권6호
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• pp.627-635
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• 2019

In this study, we developed for processing complex features using CAM software that satisfies precision for example practice and related qualification tests suiTable for CNC training purposes. In addition, functions such as location control, speed control, and processing path generation, which are the main functions of CNC machining machines, were constructed using small equipment parts, servo motors, inverters, general purpose PCs, and commercial NC software and researched with the goal of developing low-cost education equipment. In the static accuracy inspection, the degree of machine when measuring the parallelism of the X, Y and Z axes and the vibration of the main shaft did not reach the allowable value. However, we have obtained a finished product that satisfies the CNC machine book sample shape machining, detailed functions of the position control function of the CNC machine tool, linear interpolation function, circular interpolation function, and tool offset function. In the qualification test shape processing, a shape with a degree of 1/100 mm was processed to obtain position accuracy that satisfied the tolerance.

• 한국인쇄학회지
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• 제31권1호
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• pp.65-78
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• 2013

In gravure printing ink in printed flexible packaging considering the characteristics of the study more accurate color management options and results were as follows. When applying G7 calibration, P2P of the target GRACol G7 evaluate the delta $L^*$ and delta $F^*$, CMY and K-scale average of the results of delta $L^*$ and the highest tolerance G7 average of 1.5 and 3.0 are included in all the best. In addition, the average delta $F^*$ and super delta $F^*$, G7 tolerance by being included within the scope of color management, G7 calibration was possible. Target IT 8.7/4 CMYK, when applied to the calibration G7, Color gravure printing machine is applied to the average of the previous decreased from 12.4 to 3.6. In addition, if a digital proof is EPSON WT 7900 the average color applied to the previous reduction from 5.24 to 0.74 because of the gravure printing color proofing system was effective in the management. G7 calibration by applying the reference print profile of the Epson WT 7900-G-icc, the average was 0.74 coloration, and gravure-G-icc cases, the average color of the 3.60 per GRACol average of all the five colors below were included within the allowable range. Thus, the flexible packaging gravure printing color management of printed after applying the first G7 calibration, the results refer to the press by the profiling, and where best to take advantage of the profile creation was good.