• 한국미생물·생명공학회지
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• 제46권2호
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• pp.111-113
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• 2018

In this study, purification of cold-adapted protease from Janthinobacterium sp. was investigated. First, using gradient precipitation, protease was confirmed to be deposited in the 30-80% range of ammonium sulfate. Next, DEAE-Sepharose column was used for the binding of the protease under various conditions. The optimal binding condition was found to be pH 8.5 and flow rate of 30 ml/h. Under the optimal condition, the protease was purified with 29% recovery yield. This result can be useful for the purification of other cold-adapted protein.

• 한국경영과학회지
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• 제29권4호
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• pp.175-187
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• 2004

We consider the simultaneous selection of part routes for multiple part types in Flexible Manufacturing Systems (FMSs). Using an optimization framework we investigate two alternative route assignment policies. The one, called routing mix policy in the literature, specifies the optimal proportion of each part type to be produced along its alternative routes, assuming that the proportions can be kept during execution. The other one, which we propose and call pallet allocation policy, partitions the pallets assigned to each part type among the routes. The optimization framework used is a nonlinear programming superimposed on a closed queueing network model of an FMS which produces multiple part types with distinct repeated visits to certain workstations. The objective is to maximize the weighted throughput. Our study shows that the simultaneous use of multiple routes leads to reduced bottleneck utilization, improved workload balance, and a significant increase in the FMS's weighted throughput, without any additional capital investments. Based on numerical work, we also conjecture that pallet allocation policy is more robust than routing mix policy, operationally easier to implement, and may yield higher revenues.

• 제어로봇시스템학회논문지
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• 제6권10호
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• pp.936-941
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• 2000

Advanced space transportation systems, such as the National Aerospace Plane or an Orbital Transfer Vehicle, have atmospheric maneuvering capabilities. For such vehicles the use of aeroassisted orbital transfer from a high Earth orbit to a low Earth orbit, with unpowered flight in the atmosphere, has the potential for significant fuel savings compared to exoatmospheric Hohmann transfer. However, to exploit the fuel savings that can be achieved by using the Earths atmosphere to reduce the vehicles energy, a guidance law is required, and it must be able to handle large unpredictable fluctuations in atmospheric density, on the order of ${\pm}$50% relative to the 1962 US Standard Atmosphere. In this paper aeroassisted orbital transfer is considered as a differential game, with Nature controlling the atmosphere density to yield a worst case (min-max fuel required) atmosphere, from which the guaranteed playable set boundary are achieved. Inside the playable set, it is guaranteed that the vehicle achieves the optimal atmospheric exit condition for the minimum fuel consumption regardless of the atmospheric density variations.

• 동아시아식생활학회지
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• 제3권2호
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• pp.155-163
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• 1993

This study was conducted to investigate the optimal condition of the extraction of red pepper oleoresin. The yield of oleoresin form red pepper was 24~28% when it was extracted by ethanol and methanol. and 8~10% by acetone, ethylene dichloride and n-hexane. But more than 60% of portion in alcohol extracts were moisture and sugars. Capsaicin and pigment were extracted more than 70% of those in red pepper when it was extracted by ethylene dichloride Those useful components were extracted most efficiently by mixed solvents of ethanol and ethylene dichloride at the ratio of 50:150. other extracting conditions were investigated in this studies, such as optimal extraction time was more than 3 hours, temperature was 55$^{\circ}C$ and particle size was finer than 250 mesh

• 약학회지
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• 제6권2호
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• pp.18-22
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• 1962

Purified preparation of .betha.-amylase is obtained from radish root by the means of fractional precipitation with ammonium sulfate. Purified preparation saccharifies the starch, .betha.-maltose being formed. Dextrinization in the true sense does not take place. Hydrolysis ceases when approximately 50% of the theoretical yield of maltose is obtained and there remains a substance (to be .betha.-limit dextrin) which gives a blue-violet with iodine, no glucose being formed. Stability of preparation is optimal at pH 4-9 and more completely inactivated at 65.deg. in fifteen minutes. .betha.-Amylase of radish exhibits optimal activity at and near pH 5.0, which varied depending upon the buffer. Calcium and chloride ions do not effect the activities of enzyme. The results of experiments with oxidizing, alkylating and mercaptide-forming reagents which have been reported to be specific for sulfhydryl groups confirm that free sulfhydryl groups are essential to the activity of .betha.-amylase from radish.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.34-37
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• 2004

Recently advancing mobile communication tools and I.T industry, semiconductor device is requested more integrated, faster operation time and more scaled-down. Because of these reasons semiconductor device is requested multilayer interconnection. For the multilayer interconnection chemical mechanical polishing (CMP) becomes one of the most useful process in semiconductor manufacturing process. In this experiment, we focus on understand the characterize and improve the CMP technology by control of slurry flow rate. Consequently, we obtain that optimal flow rate of slurry is 170ml/min, since optimal conditions are less chemical flow and performance high with good selectivity to Ta. If we apply this results to copper CMP process. it is thought that we will be able to obtain better yield.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.92-94
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• 2007

This paper considers an optimal control problem for a remote control to an electrical drive system with a DC motor. Since it is a linear control system with time-delay subject to unknown but bounded disturbance, we construct a worst-case feedback control policy. This policy can guarantee that, for all admissible uncertain disturbances, the real system state should be in a prescribed neighborhood of a desired value, and the cost functional takes the best guarantee value. The worst-case feedback control policy is allowed to be corrected at one correction point between the initial to the final time, which is equivalent to solving a 1-level min-max problem. Since the min-max problem at the stage does not yield a simple analytical solution, we consider an approximate control policy, which is equivalent and can be solved explicitly m the numerical experiments.

• 대한기계학회논문집A
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• 제31권3호
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• pp.313-321
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• 2007

In this work, the prior indentation theory for a bulk material is extended to an indentation theory for evaluation of thin-film material properties. We first select the optimal data acquisition location, where the strain gradient is the least and the effect of friction is negligible. A new numerical approach to the thin-film indentation technique is then proposed by examining the finite element solutions at the optimal point. With this new approach, from the load-depth curve, we obtain the values of Young's modulus, yield strength, strain-hardening exponent. The average errors of those values are less than 3, 5, 8% respectively.

• 대한수학회지
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• 제37권4호
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• pp.625-643
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• 2000

In this paper we formulate an optimal control problem governed by time-delay Volterra integral equations; the problem includes control constraints as well as terminal equality and inequality constraints on the terminal state variables. First, using a special type of state and control variations, we represent a relatively simple and self-contained method for deriving new necessary conditions in the form of Pontryagin minimum principle. We show that these results immediately yield classical Pontryagin necessary conditions for control processes governed by ordinary differential equations (with or without delay). Next, imposing suitable convexity conditions on the functions involved, we derive Mangasarian-type and Arrow-type sufficient optimality conditions.

• 한국공작기계학회논문집
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• 제13권2호
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• pp.81-87
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• 2004

This paper deals with a new approach to tolerance optimization problems. Optimal tolerance allotment problems can be formulated as stochastic optimization problems. Most schemes to solve the stochastic optimization problems have been found to exhibit difficulties in multivariate integration of the probability density function. As a typical example of stochastic optimization the optimal tolerance allotment problem has the same difficulties. In this stochastic model, manufacturing system is represented by Gauss-Markov stochastic process and the manufacturing unit availability is characterized for realistic optimization modeling. The new algorithm performed robustly for a large deviation approximation. A significant reduction in computation time was observed compared to the results obtained in previous studies.