• 한국항해항만학회지
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• 제30권7호
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• pp.561-566
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• 2006

In this paper, we propose a new ship scheduling set packing model considering limited risk or variance. The set packing model is used in many applications, such as vehicle routing, crew scheduling, ship scheduling, cutting stock and so on. As long as the ship scheduling is concerned, there exits many unknown external factors such as machine breakdown, climate change and transportation cost fluctuation. However, existing ship scheduling models have not considered those factors apparently. We use a quadratic set packing model to limit the variance of expected cost of ship scheduling problems under stochastic spot rates. Set problems are NP-complete, and additional quadratic constraint makes the problems much harder. We implement Kelley's cutting plane method to replace the hard quadratic constraint by many linear constrains and use branch-and-bound algorithm to get the optimal integral solution. Some meaningful computational results and comments are provided.

• 산업경영시스템학회지
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• 제24권62호
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• pp.21-32
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• 2001

The two-dimensional guillotine cutting problem is to maximize sum of piece profits that cut from one stock rectangle and widely applied in the industry. The branch-and-bound method for this problem uses complementarily several upper bounds(the Gilmore and Gomoryp[8]'s two-dimensional knapsack function and the Hifi and Zissimopoulos[10]'s method using one-dimensional knapsack problem, etc) to reduce the number of searched nodes. These upper bounds has a shortcoming that does not consider the bound and layout of pieces simultaneously. In this paper, we propose an efficient upper bound which can complement the shortcoming of existing upper bounds. The proposed upper bound needs less memory spaces and computing time. Computational results show that the proposed upper bound significantly contribute to reduce the computational amount of time and number of searched nodes in tree.

• 한국정밀공학회지
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• 제32권8호
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• pp.693-698
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• 2015

Recently, the quality of products after the corresponding machining processes were scrutinized in the interest of maintaining a high product-quality standard. The structure and stability of machine tools are important for the prediction of product quality. A structural analysis needs to be carried out to achieve the stable design of machine tools before the initial design stage in the manufacturing process of a precision product. In this study, a structural analysis was carried out using a finite element analysis (FEA) simulation to obtain the design stability of the main parts of a grinding machine. The sizes and locations of both the maximum stress and deformation in consideration of the cutting force of the chuck, tail stock, and bearing of the grinding machine were analyzed. Finally the grinding machine was successfully developed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.456-463
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• 2005

This paper describes a design process of end-milling cutters: solid model of the designed cutter is constructed along with computation of cutter geometry, and the wheel geometry as well as wheel positioning data fur fabricating end-mills with required cutter geometry is calculated. In the process, the main idea is to use the cutting simulation method by which the machined shape of an end-milling cutter is obtained via Boolean operation between a given grinding wheel and a cylindrical workpiece (raw stock). Major design parameters of a cutter such as rake angle, inner radius can be verified by interrogating the section profile of its solid model. We studied relations between various dimensional parameters and proposed an iterative approach to obtain the required geometry of a grinding wheel and the CL data fer machining an end-milling cutter satisfying the design parameters. This research has been implemented on a commercial CAD system by use of the API function programming, and is currently used by a tool maker in Korea. It can eliminate producing a physical prototype during the design stage, and it can be used fur virtual cutting test and analysis as well.

• Journal of Periodontal and Implant Science
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• 제29권3호
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• pp.703-715
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• 1999

The purpose of this study was to evaluate the degree of wear of periodontal curet's cutting edges made by three different manufacturers. In the first case of the experiment, this study was done with each new curett in the following three experiment. Twelve new double-ended No. 11/12 Gracy curettes from three different manufacturers (A, B and C) was randomly selected from our stock at first test. They were weared by wear tester with fixed pressure and limited distance. This study measured the width of worn curettes'cutting edge. The results were as follows ; 1)In 50 times experiment, this study discoverd that each manufacturer's curette was appeared with different degree of wear (p<0.01) 2)In 100 times experiment, this study result similarly to the 50 times experiment(p<0.01). 3)In 150 times experiment, the result of this study were alike as the X50 experiment and X100 experiment. In the second case of the experiment, the study was done with a curett of a manufacturer in the following three experiment. Two double-ended No. 11/12 Gracy curette from three different manufactures (A, B and C) was randomly selected from our stock at second test. 1)In 50 times experiment, this study discovered that each manufacturer's curette was appeared with different degree of wear (p<0.05). 2)In 100 times experiment, the result was same, compared with the 50 times experiment. 3)In 150 times experiment, this study also discovered that the result was same with the result of the upper two cases. In conclusion, this study discovered that the two cases of experimental were shown with a same result.

• 식물조직배양학회지
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• 제28권2호
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• pp.81-85
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• 2001

포도의 기내 삽목방법을 이용하였을 때 액아의 신장에 미치는 생장조절제의 영향과 이들 유묘의 virus 이병 정도에 관해 검정한 결과를 요약하면 다음과 같다. 3/4 MS 기본배지에 BA 0.1 또는 0.5 mg/L와 NAA 0.05 mg/L를 혼용한 것이 액아로부터 신초의 신장에 적합하였다. 기외이식용 상토는 vermiculite와 peat moss를 3: 1 등량용적 비율로 혼합한 경우 활착률이 가장 높았다. 포장에서 재배되고 있던 'Schuyler'외 2품종을 ELISA 검정한 결과 3품종 모두 GLRV Ⅰ, GFLV, ArMV에는 음성반응을 나타내었으나 GLRV Ⅲ에는 감염되 어 있었으며, 이병률은 30∼75%로 품종 간 차이가 현저하였다. 경정배양에서 얻은 유묘의 virus 검정 결과, GLRV Ⅰ, GFLV, ArMV는 3품종 모두 음성반응을 나타내었으나 'Schuyler'와 'Muscat of Alexandria'는 GLRV Ⅲ에 양성반응을 나타내어 이병률은 각각 37.5 %와 12.5%였다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 추계학술발표회 논문집
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• pp.39-41
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• 2011

The recycling rate of recovered paper in Korea is the highest in the world, 92%, but remanufacturing yield is low due to the extremely poor quality of the paper. The poor quality, in turn, influences to the reject amount in deinking process. To increase the yield of old newspaper recycling process, hydrophobic degree of inorganic pigments of deinking stock must be reduced. To determine the hydrophobicity, Pitch Potential Deposit Tester (PDT) was newly designed and applied with respect to the SB latex property of various quality used in Korea; its hydrophobic degree according to Tg, gel content, charge and particle size of latex and optimum designing condition of SB latex. And below are the conclusions: 1. The reason of excessive reject from old newspaper deinking process for total amount of printed ink is loss of inorganic pigments. When lipase, a biochemical catalyst, was applied with the purpose of preventing inorganic pigments loss about more than 70% of total reject weight and promoting hydration of pulp for deinking, deinking process yield of pre flotation secondary stage increased remarkably without any changes of deinking efficiency. 2. Lipase improved deinking stock by cutting ester linkage on surface of hydrophobic materials to promote its hydration. From this, it reached the conclusion that hydration degree of stock exercises significant effect on flotation deinking process yield. 3. Inorganic alkali promotes hydration of deinking stock. But there have been needs for more fundamental measures other than inorganic alkali of promoting hydration for yield improvement. For this, this study intended to find out reasons of chemical properties change on surface of hydrophobic material by change of pH. 4. Pitch Deposit Test (PDT) was performed for understanding principle of why surface of coating flake from OMG is hydrophobic and why it becomes hydrophilic when pH of stock is alkaline. As a result of this test, it is determined that swelling property by change of pH of latex film, which were used as coating adhesive is the reason for hydrophobic change. 5. Hydrophilicity of coating flake increased with hydrophilic pigments. And as more of SB Latex adhesive was used and higher of calcium hardness of stock became, its hydrophilicity decreased. SB Latex adhesive film is reformed by mechanical friction. For having hydrophilicity under neutral pH, strong bruising action such as kneading is required. 6. Because swelling of adhesive film decreases as Tg of SB latex gets lower and mean diameter gets smaller, it shows hydrophobicity under neutral pH. This lowers hydrophilicity of coating flake, which leads to easy elimination with flotation reject on DIP process. Therefore, for improving future flotation yield, it is necessary to develop to use eco-friendly clean SB latex by raising Tg and increasing mean diameter for recycling, and as a result, to reduce excessive loss of coating flake as a reject from deinking process.

• Journal of Forest and Environmental Science
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• 제30권2호
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• pp.218-225
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• 2014

Studies were carried out to standardize and develop a suitable macro-propagation technology for large scale production of superior clonal stock through stem cuttings in Commiphora wightii Arnott (Bhandari), a data deficient medicinal plant of arid region. For the purpose, three experiments were conducted. The first experiment was tried to elucidate the impact of various cutting diameters (0.50-0.75 cm, 0.75-1.00 cm, 1.00-1.50 cm, and >1.50 cm) in combination with varying growing conditions (sunlight, shade house and mist chamber) on shoot sprouting and rooting without using exogenous plant growth regulators. Cutting diameter (size 0.75-1.00 cm) in mist chamber has shown maximum sprouting (90.00%) and rooting (73.33%), primary root (6.67) and secondary root (16.67) followed by 1.00-1.51 cm in mist chamber. Minimum sprouting (40.00%), rooting (33.33%), number of shoot (1.33), primary root (1.00) and number of secondary root (1.00) was recorded in cutting diameter (size >1.50 cm) in sunlight. Second experiment was performed to find out optimum growth regulator concentration of rooting hormone (100, 200, 500 and 1000 ppm) of Indole-3-acetic acid (IAA) and Indole-3-butyric Acid (IBA) on adventitious root formation on cuttings diameter (size 0.25-0.50 cm) in comparison to control. Maximum rooting percentage (93.33%) was recorded in 200 ppm followed by 500 ppm (86.66%) of IBA as compared to control, which showed only 60 per cent sprouting. Third experiment was performed with newly formed juvenile micro-cuttings treated with varying concentrations of IAA and IBA. The juvenile cuttings (size 6-10 cm, basal dia <0.25 cm) were selected as micro-cuttings. The cuttings treated with IBA (500 ppm) showed 64.30% rooting as compared to other treatments. Results of above experiments indicate that cuttings (size 0.75-1.00 cm dia) may be developed in mist chamber for better performance. While using heavier cuttings, no growth promoting hormones is required however; growth regulator 200 ppm concentration of IBA rooting hormone was observed optimum for promoting macro-propagation in stem cuttings of lower diameter class (0.25-0.50 cm).

• 한국어병학회지
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• 제27권2호
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• pp.127-131
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• 2014

넙치에 적합한 표지방법을 조사하기 위하여 표지 후 누적폐사율, 혈액생화학적 성상과 조직병리학적 조사를 하였다. 본 연구에서는 아가미뚜껑 절단, 배지느러미 50%와 100% 절단 방법을 사용하였다. 누적폐사율은 아가미뚜껑 절단구가 가장 높았다. 배지느러미 100% 절단구와 아가미뚜껑 절단구는 절단 후 13일 째 조직병리학적 변화를 나타내었다: 간에서 화농성 염증반응, 체신에서 섬유성 염증반응이 관찰되었다. 본 연구결과 50% 배지느러미 절단구가 가장 효과적인 표지방법인 것으로 판단된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.392-392
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• 2000

This study performs optimization of paper mill scheduling using MINLP(Mixed-Integer Non-Linear Programming) method and 2-step decomposing strategy. Paper mill process is normally composed of five units: paper machine, coater, rewinder, sheet cutter and roll wrapper/ream wrapper. Various kinds of papers are produced through these units. The bottleneck of this process is how to cut product papers efficiently from raw paper reel and this is called trim loss problem or cutting stock problem. As the trim must be burned or recycled through energy consumption, minimizing quantity of the trim is important. To minimize it, the trim loss problem is mathematically formulated in MINLP form of minimizing cutting patterns and trim as well as satisfying customer's elder. The MINLP form of the problem includes bilinearity causing non-linearity and non-convexity. Bilinearity is eliminated by parameterization of one variable and the MINLP form is decomposed to MILP(Mixed-Integer Linear programming) form. And the MILP problem is optimized by means of the optimization package. Thus trim loss problem is efficiently minimized by this 2-step optimization method.