• Journal of Information Technology Applications and Management
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• v.18 no.1
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• pp.125-141
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• 2011

As the sales volume of online shops increases, the job burden in the back-offices of the online shops also increases. Order picking is the most labor-intensive operation among the jobs in a back-office and mid-size pure click online shops are experiencing the time delay and complexity in order picking nowadays while fulfilling their customers' orders. Those warehouses of the mid-size shops are based on manual systems, and as order pickings are repeated, the warehouses get a mess and lots of products in those warehouses are getting missing, which results in severe delay in order picking. To overcome this kind of problem in online clothing shops, we research a methodology to locate warehousing products. When products arrive at a warehouse, they are packed into a box and located on a rack in the warehouse. At this point, the operator should determine the box to be put in and the location on the rack for the box to be put on. This problem could be formulated as an Integer Programming model, but the branch-and bound algorithm to solve the IP model requires enormous computation, and sometimes it is even impossible to get a solution in a proper time. So, we relaxed the problem, developed a set of heuristics as a methodology to get a semi-optimum in an acceptable time, and proved by an experiment that the solutions by our methodology are satisfactory and acceptable by field managers.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.990-994
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• 2004

This paper presents a method to predict the transient characteristic of the air lubricated slider head in a hard disk drive by using optimization technique. The time dependent modified Reynolds equation based on the molecular slip flow approximation equations was used to describe the fluid flow within the air bearing and the implicit finite difference scheme is applied to calculate the pressure distribution under the slider head. The exhaustive search combined with the Broyden-Fletcher-Goldfarb-Shanno method were employed to obtain optimum design variables which are taper angle, rail width and taper length in order to keep the forces and moments acting on the slider head in dynamic equilibrium. The results show that the optimal head slider of the magnetic head has good stability characteristic that can reach the steady state within 0.5 microsecond.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.499-507
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• 2016

Medical imaging techniques such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT) and Ultrasound (US) produce a large amount of digital medical images. Hence, compression of digital images becomes essential and is very much desired in medical applications to solve both storage and transmission problems. But at the same time, an efficient image compression scheme that reduces the size of medical images without sacrificing diagnostic information is required. This paper proposes a novel threshold-based medical image compression algorithm to reduce the size of the medical image without degradation in the diagnostic information. This algorithm discusses a novel type of thresholding to maximize Compression Ratio (CR) without sacrificing diagnostic information. The compression algorithm is designed to get image with high optimum compression efficiency and also with high fidelity, especially for Peak Signal to Noise Ratio (PSNR) greater than or equal to 36 dB. This value of PSNR is chosen because it has been suggested by previous researchers that medical images, if have PSNR from 30 dB to 50 dB, will retain diagnostic information. The compression algorithm utilizes one-level wavelet decomposition with threshold-based coefficient selection.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.106-110
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• 1998

The present study has been undertake to obtain the fundatmental data of optimum germination condition and to establish storage time for artificial pollinationin Codonopsis lancelata pollen. In vitro condition for germination of freshly collected and stored pollen were examined. The optium temperature for germination of fresh pollen was $25^{\circ}C$. The optium sucrose concentration in the medium ranged from 30 to 40 % and optium pH 6.0% for pollen germination. The rate of pollen germination accelerated considerably in the medium with 1% agar. 30% sucrose, and pH 6. C. lanceolata pollen remained viable for 15 days when stored at 5$^{\circ}C$ with silica gel as desiccant.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.2
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• pp.197-205
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• 1986

In this paper, we present an efficient test algorithm for data processing function of MC68000 \ulcorner. The test vector for functional testing is determined by stuck-at, coupling and transition fault for data storage and transfer. But for data manipulation it is determined by a boolean function of micro-operation. This test algorithm is composed of 3 parts, choosing optimum test instructions for maximizing fault coverage and minimizing test process time, deciding the test order for minimizing test ambiguity, and processing the actual test.

• Korean Journal of Medicinal Crop Science
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• v.9 no.4
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• pp.265-268
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• 2001

This experiment was conducted to investigate the effects of temperature, light, seed harvesting time, storage temperature, and period on its germination of Astragalus membranaceus. Optimum germination temperature was ${20{\sim}25^{\circ}C}$ and it was found to be light insensitive seed. The germination rates were not significantly different between 1-year and 2-year old plants, and seed harvesting times. Seeds stored at such cold temperatures as ${-4^{\circ}C\;and\;-20^{\circ}C}$ for 15 months showed over 80% in germination rate at the 6th day after placement. On the other hand, low germination rate of 60% at the 11th day was observed from the seeds stored at $4^{\circ}$ and room temperature.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.3
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• pp.240-244
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• 2011

The high cost of crystalline silicon solar cells has been considered as one of the major obstacles to their terrestrial applications. Spin on doping (SOD) is presented as a useful process for the manufacturing of low cost solar cells. Phosphorus (P509) was used as an n-type emitters of solar cells. N-type emitters were formed on p-type EFG ribbon Si wafers by using a SOD at different spin speed (1,000~4,000 rpm), diffusion temperatures ($800^{\circ}C{\sim}950^{\circ}C$), and diffusion time (5~30 min) in $N_2+O_2$ atmosphere. With optimum condition, we were able to achieve cell efficiency of 14.1%.

• Mycobiology
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• v.45 no.4
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• pp.240-254
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• 2017

Cereal grains are the most important food source for humans. As the global population continues to grow exponentially, the need for the enhanced yield and minimal loss of agricultural crops, mainly cereal grains, is increasing. In general, harvested grains are stored for specific time periods to guarantee their continuous supply throughout the year. During storage, economic losses due to reduction in quality and quantity of grains can become very significant. Grain loss is usually the result of its deterioration due to fungal contamination that can occur from preharvest to postharvest stages. The deleterious fungi can be classified based on predominance at different stages of crop growth and harvest that are affected by environmental factors such as water activity ($a_w$) and eco-physiological requirements. These fungi include species such as those belonging to the genera Aspergillus and Penicillium that can produce mycotoxins harmful to animals and humans. The grain type and condition, environment, and biological factors can also influence the occurrence and predominance of mycotoxigenic fungi in stored grains. The main environmental factors influencing grain fungi and mycotoxins are temperature and $a_w$. This review discusses the effects of temperature and $a_w$ on fungal growth and mycotoxin production in stored grains. The focus is on the occurrence and optimum and minimum growth requirements for grain fungi and mycotoxin production. The environmental influence on aflatoxin production and hypothesized mechanisms of its molecular suppression in response to environmental changes are also discussed. In addition, the use of controlled or modified atmosphere as an environmentally safe alternative to harmful agricultural chemicals is discussed and recommended future research issues are highlighted.

• Microbiology and Biotechnology Letters
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• v.9 no.1
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• pp.7-19
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• 1981

The production of gluconic acid from glucose by the resting cell system of Aspergillus niger was studied. It was found that the conversion products from glucose by the resting cell system were markedly influenced by the pH, temperature, substrate concentration, aeration, metal ions, cultivation time and storage conditions of the resting cells. Conversion products were identified as gluconic acid by the thin layer chromatography and infrared spectrophotometry. These conversions were greatly stimulated by addition of $Mg^{++}$, and S $n^{++}$, but showed inhibitory effects by C $u^{++}$, H $g^{++}$, C $d^{++}$, A $g^{+}$ and cyanide. For the optimum cell storage, it was effective to be kept at -$25^{\circ}C$ in 0.05M phosphate buffer solution of pH 7.0. The gluconic acid production by the resting cell system was more effective than those of the fermentation with respect to cultivation time, yield, recovery and re-use of the cell.l.l.l.l.l.l.

• Progress in Superconductivity and Cryogenics
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• v.17 no.2
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• pp.45-49
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• 2015

It has been well known that a toroid is the inevitable shape for a high temperature superconducting (HTS) coil as a component of a large scale superconducting magnetic energy storage system (SMES) because it is the best option to minimize a magnetic field intensity applied perpendicularly to the HTS wires. Even though a perfect toroid coil does not have a perpendicular magnetic field, for a practical toroid coil composed of many HTS pancake coils, some type of perpendicular magnetic field cannot be avoided, which is a major cause of degradation of the HTS wires. In order to suggest an optimum design solution for an HTS SMES system, we need an accurate, fast, and effective calculation for the magnetic field, mechanical stresses, and stored energy. As a calculation method for these criteria, a numerical calculation such as an finite element method (FEM) has usually been adopted. However, a 3-dimensional FEM can involve complicated calculation and can be relatively time consuming, which leads to very inefficient iterations for an optimal design process. In this paper, we suggested an intuitive and effective way to determine the maximum magnetic field intensity in the HTS coil by using an analytic and statistical calculation method. We were able to achieve a remarkable reduction of the calculation time by using this method. The calculation results using this method for sample model coils were compared with those obtained by conventional numerical method to verify the accuracy and availability of this proposed method. After the successful substitution of this calculation method for the proposed design program, a similar method of determining the maximum mechanical stress in the HTS coil will also be studied as a future work.