• 대한기계학회논문집A
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• 제33권9호
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• pp.903-912
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• 2009

This study is focused on simulation-based dimensional tolerance optimization process (DTOP) to minimize vehicle pulls by reduction of dimensional variation in front suspension system. In previous studies, the effect of tires and wheel alignment sensitivity have mainly been investigated to eliminate vehicle pulls in nominal design condition without allocating optimal tolerance level for selected components, among various factors regarding vehicle pulls such as vehicle design parameters, vehicle weight balance, tires, and environmental factors. Unfortunately, there are wide variations in the real vehicle, and these have impacted actual vehicle pulls, especially wheel alignment effects from suspension geometry variation has not been considered in the previous studies. In the tolerance design of suspension, tolerance variables with the uncertainty such as parts dimensional variation, assembly process, datum position and direction, and assembly tool tolerance has a great influence on the variation of the suspension dimensional performances. This study introduces total vehicle pull prediction model in considering major key factors for vehicle pull sensitivity. The Monte Carlo-based tolerance analysis model using Taguchi robust method is developed to optimize dimensional tolerance parameters, satisfying on the target variation level.

• 한국정보통신학회논문지
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• 제10권12호
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• pp.2157-2165
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• 2006

항등 비트율 서비스를 위한 대표적인 이용자 트래픽 통제 알고리즘인 GCRA에 있어서 네트워크의 과부하와 전송 도중 불가피하게 발생하는 전송지연 변동에 따른 이용자 트래픽의 과도한 손실을 방지하기 위해서는 적절한 전송 지연변동 허용치의 설정이 매우 중요하다. 본 논문에서는 항등 비트율의 소스 트래픽에 대한 GCRA 순응검사에서 지연변동 허용치의 범 위에 따른 GCRA의 성능을 여러 측면에서 분석하고 적절한 지연변동 허용치 설정을 위한 가이드라인을 제시한다.

• 한국정밀공학회지
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• 제13권6호
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• pp.78-89
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• 1996

Every mechanical component 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. Since the range of shape variation can be represented by the variation of the coordinate system attached to the shape, the transformation matrix of the coordinate system would mathematically express the range of shape variation if the interval numbers are inserted for the elements of the transformation matrix. For the shape entity specified by the geometric tolerance with reference to datums, its range of variation can be also derived by propagating the transformation matrices composed of interval numbers. The propagation depends upon the order of precedence of datums.

• The Korean Journal of Ecology
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• 제19권1호
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• pp.36-46
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• 1996

Variation of Al tolerance in Pinus densiflora, P. rigida and P. thunbergii was investigated in a solution culture. Root length decreased as Al concentration increased, and decreased more in dilute culture media than in dense one. Aluminum tolerance based on relative root length was in the order of P. rigida ＞ P. densiflora ＞ P. thunbergii. Al content in tissue increased as Al concentration of the media increased, but the reverse was true for content of Ca and Mg. Al tolerance for root length showed intraspecific variation, even under the same Al concentration in the media.

• Fisheries and Aquatic Sciences
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• 제3권2호
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• pp.88-96
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• 2000

The present study estimated the variation of early survival of chum salmon families with respect to temperature and size after transfer to seawater. Heritability for seawater tolerance of half-sib families was also estimated at 45 days after hatching. Gametes were collected from 6 male and 18 female chum salmon to make 18 paternal half-sib families. Seawater tests were carried out at 3, 7 and $12^{\circ}C$ of $32\%$ seawater and compared with freshwater. Survival was significantly affected by seawater temperature. The highest seawater tolerance was obtained in 45-day old chum salmon at $7^{\circ}C$ seawater and the lowest seawater tolerance was obtained at $3^{\circ}C$. Overall survivals in seawater tolerance at $32\%$ varied among families. There were significant variance in fry survival among females (P=0.0001), and among males (P=0.0001). The heritabilities of survival in seawater in chum salmon were estimated to be 0.32-0.34 for the sire components at 45 days after hatching in 1998.

• 한국국방경영분석학회지
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• 제27권1호
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• pp.101-113
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• 2001

Taguchi and VTA(variation Transmission Analysis) methods have been widely used recently as new methods for product design. In this study, Taguchi method using analysis of variance and VTA method using regression analysis are reviewed and compared with each other in terms of parameter design and tolerance design. In analysis of variance, variation of quality characteristics arises from noise factors, therefore the optimal levels of design factors are selected to minimize the effect of noise factors. n regression analysis, variation of quality characteristics arises from variation of each own design factors. As a method to reduce variation of these quality characteristics, sensitivity analysis was performed for each design factors. An example of calculating tolerance interval for the given defect rate in PPM is also introduced. Especially, the new method is suggested to increase the estimation accuracy of variation of quality characteristics through regression analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.191-196
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• 2014

In the evaluation of measured noise data, tolerance shall be decided based on the uncertainty. The uncertainty has frequency variations due to the different standard deviations at each frequency. Therefore, tolerance shall be differently decided for each frequency with the same confidence probability. In the report, the evaluation method considering the frequency variation of uncertainty will be introduced. From the approach, considering the actual noise distribution characteristics of the ships, the tolerance shall be decided for each frequency with the same probability, but the overall averaged value shall be kept to the value designated in each notation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.995-999
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• 1995

In spindle-bearing system, the displacement characteristics of the bearing by the load applied on the spindle are affected greatly by the assembling tolerance between the spindle and housing assembled to support the bearing. Also in spindle system of rotational operation, the compliance characteristic of the bearing is expected to be varied frequently by the thermal deformation of the spindle and the housing. To predict the thermal deformation of the spindle including heat generation of the bearing, we need to examine the effect on the compliance of spindle-bearing system by the assembling tolerance. In this paper, we proposed the load-displacement relation expression considering the effect which the variation of contact pressure due to the radial directional assembling tolerance between the bearing and the housing influences on the axial and radial directional displacement characteristics of the bearing. Furthermore, for several assembling systems of bearings and housings having all different assembling tolerances, we proposed a method to predict exactly the variation of the bearing preload which is sensitive to the thermal deformation by showing the propriety with experimental results.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2004년도 정기총회 및 제33차 춘계 학술대회
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• pp.349-352
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• 2004

Twelve strains of Lactobacillus acidophilus isolated from feces of human or animal sources were tested for probiotic properties such as cholesterol assimilation, bile and acid tolerances, and CLA production. Although the cultures showed some variation with respect to each test, the 12 strains could be classified into 3 groups based on their ability to assimilate cholesterol. The cholesterol assimilation showed positive correlation with bile tolerance and negative correlation with acid tolerance. The cholesterol assimilation of L. acidophilus strains may not be related to the deconjugation activity, but may in fact be attributed to its bile tolerance. CLA production by lactic acid bacteria (LAB) exhibited a wide variation that ranged from 2.69 to 7.64 mg/g fat. CLA production of Bifidobacterium longum ATCC 15707 was the highest among the LAB tested, but there was no evidence for differences in CLA production between genus and species.

• 대한안전경영과학회지
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• 제2권1호
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• pp.89-97
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• 2000

This paper shows the study for development inprocess measuring magnetic sensor for tolerance control, First, we fabricated and annealed sample amorphous ribbons which were made of ($CO_{0.94}$$Fe_{0.06}$)$_{79}$$Si_{2}$$b_{19}$ having near zero magnetostrictive. It had 12［$\mu\textrm{m}$］ of thickness, 10［mm］ of length, and 2.5［mm］ of width. Then, we measured the magnetic characteristics such as frequency dependency over impedance variation rate and position change over impedance variation. As the results of the evaluation, we found that the sample ribbons had excellent sensor characteristics. Then, we made sensors by using the sample ribbons, As the results of the measurements, it proved that the ribbon could be used as excellent magnetic sensor for which it was possible to control inprocess measurement within the tolerance range(~$\mu\textrm{m}$ ).