• Microbiology and Biotechnology Letters
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• v.25 no.3
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• pp.258-265
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• 1997

The effects of medium pH and culture temperature on the expression and secretion of inulinase and invertase were investigated with recombinant Saccharomyces cerevisiae cells. These cells were obtained by transformation of 2$\mu$-based plasmids pYI10 and pYS10 which contain Kluyveromyces marxianus inulinase gene (INU1A) and S. cerevisiae invertase gene (SUC2), respectively, in the downstream of GAL1 promoter. The expression level and localization of inulinase and invertase were not affected significantly by the initial medium pH: secretion efficiencies of inulinase and invertase into the medium were about 90% and 60%, respectively, in the pH ranges of 4.0 to 6.5. However, the expression and secretion of both enzymes were strongly dependent on the culture temperature. The highest expression (7.7 units/mL) and secretion (6.7 units/mL) of inulinase were observed at 28$\circ$C and 30$\circ$C. As a consequence of decreased localization of inulinase in the periplasmic space, the secretion efficiency increased from 68% at 20$\circ$C, to 95% at 35$\circ$C,. The total expression level and secretion efficiency of invertase increased from 19 units/mL and 55% at 20$\circ$C to 25 units/mL and 68% at 35$\circ$C, respectively. Irrespective of the culture temperature, the invertase activity in the cellular fraction (periplasmic space and cytoplasmic fractions) was kept constant at around 33-45%.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.263-266
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• 1998

Several constraints in machine duplication cost, machining capability, cell space capacity, intercell moves and exceptional elements(EEs) are main problems that prevent achieving the goal of ideal Cellular Manufacturin System (CMS) environment. Minimizing intercell part traffics and EEs are the main objective of the cell formation problem as it's a critical point that improving production efficiency. Because the intercell moves could be changed according to the sequence of operation, it should be considered in assigning parts and machines to machine cells. This paper presents a method that eliminates EEs under the constraints of machine duplication cost and cell space capacity attaining two goals of minimizing machine duplications and minimizing intercell moves simultaneously. Developing an algorithm that calculates the machine duplications by cell-machine incidence matrix and part-machine incidence matrix, and calculates the exact intercell moves considering the sequence of operation. Based on the number of machine duplications and exact intercell moves, the goal programming model which satisfying minimum machine duplications and minimum intercell moves is developed. A linear programming model is suggested that could calculates more effectively without damaging optimal solution. A numerical example is provided to illustrate these methods.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.10
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• pp.61-67
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• 2004

The next generation cellular wireless communication systems require high data rate transmissions and large system capacities. In order to meet these requirements, multiple antennas can be used at the base and mobile stations, forming MIMO(Multiple Input Multiple Output) channels. This paper proposes a MIMO SDMA(Space Division Multiple Access) technique with dynamic slot allocation which allows the transmitter to efficiently transmit parallel data streams to each of multiple receivers. The proposed technique can increase system capacities significantly by transmitting a larger number of data streams than conventional MIMO techniques while minimizing the performance degradation due to the beamforming dimension reduction.

• Journal of Korean Dental Science
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• v.8 no.2
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• pp.89-94
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• 2015

As popularity of dental implantation is increasing, the number of cases associated with complications also increase. Evaluation on diabetes mellitus is often neglected due to the disease's irrelevance to implantability. However, patients with diabetes mellitus are susceptible to infection due to impaired bactericidal ability of neutrophils, cellular immunity and activity of complements. Due to this established connection between diabetes mellitus and infection, a couple of cases were selected to present patients with diabetes mellitus with glycemic incontrollability, suffering from post-implantation dentigerous inter-fascial space abscess.

• Journal of Integrative Natural Science
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• v.2 no.2
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• pp.55-58
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• 2009

A ligand-receptor docking program is an indispensible tool in modern pharmaceutical design. An accurate prediction of small molecular docking pose to a receptor is essential in drug design as well as molecular recognition. An effective docking program requires the ability to locate a correct binding pose in a surprisingly complex conformational space. However, there is an inherent difficulty to predict correct binding pose. The odds are more demanding than finding a needle in a haystack. This mainly comes from the flexibility of both ligand and receptor. Because the searching space to consider is so vast, receptor rigidity has been often applied in docking programs. Even nowadays the receptor may not be considered to be fully flexible although there have been some progress in search algorithm. Improving the efficiency of searching algorithm is still in great demand to explore other applications areas with inherently flexible ligand and/or receptor. In addition to classical search algorithms such as molecular dynamics, Monte Carlo, genetic algorithm and simulated annealing, rather recent algorithms such as tabu search, stochastic tunneling, particle swarm optimizations were also found to be effective. A good search algorithm would require a good balance between exploration and exploitation. It would be a good strategy to combine algorithms already developed. This composite algorithms can be more effective than an individual search algorithms.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.38-50
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• 2018

Spatio-temporal load forecasting (STLF) is a foundation for building the prediction-based power map, which could be a useful tool for the visualization and tendency assessment of urban energy application. Constructing one point-forecasting model for each electricity cell in the geographic space is possible; however, it is unadvisable and insufficient, considering the aggregation features of electricity cells and uncertainties in input variables. This paper presents a new STLF method, with a data-driven framework consisting of 3 subroutines: multi-level clustering of cells considering their aggregation features, load regression for each category of cells based on SLS-SVRNs (sparse least squares support vector regression networks), and interval forecasting of spatio-temporal load with sampled blind number. Take some area in Pudong, Shanghai as the region of study. Results of multi-level clustering show that electricity cells in the same category are clustered in geographic space to some extent, which reveals the spatial aggregation feature of cells. For cellular load regression, a comparison has been made with 3 other forecasting methods, indicating the higher accuracy of the proposed method in point-forecasting of spatio-temporal load. Furthermore, results of interval load forecasting demonstrate that the proposed prediction-interval construction method can effectively convey the uncertainties in input variables.

• Korean Journal of Veterinary Research
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• v.35 no.3
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• pp.553-562
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• 1995

To elucidate pathologic change of skin in porcine exudative epidermitis, immunohistochemical and electron microscopical observations were carried out in the skin of the suckling pigs inoculated with Staphylococcus hyicus subsp hyicus which were isolated from natural case. In immunohistochemistry, ATPase-positive dendritic cells were more populated in epidermo-dermal junctional areas and perivascular area in dermis than in epidermal area as the disease was proceeded. These dendritic cells were identified as Langerhans cell by immunoperoxidase staining and these cells were populated granulomatous bodies. Electron microscopical study showed various retrogressive degeneration and vacuolation of epidermal cell organelles with retention of amorphorous exudates in intercellular space, and cellular seperation. Langerhans cells present in intercellular space of epidermis were populated in epidermo-dermal junctional areas, in dermis, and around granulomatous bodies. Langerhans cells contained decreased Birbeck granules in number but increased lysosome and ribosome. These cells were in contact with lymphocytes. This study was discussed relation between the various immunocytes and the formation of granulomatous bodies, and this inflammation was considered as delayed type hypersensitivity.

• Current Optics and Photonics
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• v.5 no.2
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• pp.114-120
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• 2021

Free-space optical (FSO) communication is considered to be a potential solution to congestion in the radio-frequency spectrum and last-mile-access bottleneck issues in future cellular communication networks, such as 5G and beyond. However, FSO link performance may degrade significantly due to irradiance fluctuations and random temporal fluctuations from atmospheric turbulence. Therefore, in this work the main objective is to reduce the effect of the atmospheric turbulence by considering a multihop FSO communication system with amplify-and-forward relaying supported by a radio-frequency (RF) link, which form a hybrid FSO/RF communication system. The FSO link is assumed to follow the gamma-gamma fading model, which represents strong turbulence. Also, the RF link is modeled by a Rayleigh distribution. The performance of the considered system, in terms of the outage probability and average bit-error rate (BER), is investigated and analyzed under various weather conditions and pointing errors. Furthermore, the effect of the number of employed relay nodes on the performance of the system is investigated. The results indicate that the considered system reduces outage probability and average BER significantly, especially for low channel quality. Finally, the closed-form expressions derived in this work are compared to the results of Monte Carlo simulations, for verification.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1170-1174
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• 2009

Two frequency-reconfigurable antennas have been designed and combined in a space with limited volume, i.e., 40mm ${\times}$ 20mm ${\times}$ 6mm. Each antenna can be reconfigured to operate at different frequency bands depending on the state of an embedded switch, which is implemented using a PIN diode. The first antenna can be switched between 0.82GHz ${\sim}$ 0.96GHz band (GSM/ CDMA) and 1.7GHz ${\sim}$ 2.17GHz band (DCS/ PCS/ WCDMA), which are cellular bands. The second antenna can be switched between 3.4GHz ${\sim}$ 3.6GHz band (mWiMax) and 2.3GHz ${\sim}$ 2.5GHz, 5.15GHz ${\sim}$ 5.35GHz bands (WiBro/ WLAN 11a/b/g/n), which are connectivity bands. The proposed combined antenna operates both over cellular bands and connectivity bands concurrently. The choice of the operation bands is made independently by the states of the two switches.

• Korean Journal of Crystallography
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• v.16 no.2
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• pp.138-140
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• 2005

A new crystal of helminth glutathione S-transferase, 28 kDa isozyme from Clonorchis sinensis has been grown from a 20% PEG MME 550 solution containing 50 mM $CaCl_{2}$ in 0.1 M bis-Tris buffer (pH 6.5) in $2{\sim}3$ days. The crystals diffract to $3.0{\AA}$ resolution and belong to the orthorhombic space group $P2_{1}2_{1}2_{1}$ with cell parameters $a=62.58{\AA},\;b=69.92{\AA},\;and\;c=339.67{\AA}$.