• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1660-1668
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• 2008

The WiBro was adopted to the 3G international standard. By the change of specification from Wave 1 to Wave 2, MIMO technology is applied in order to increase the speed of downlink. By MIMO the RF part of WiBro base station is increased to 2 Tx paths. Therefore, the size of RF part is bigger and material cost is increased. For reducing these demerits, the RF part which is consisted of PA, LNA, and TDD switch is designed to one complex RF unit. Also, the experimental results of the RF unit have been discussed. Since the complex RF unit is more compact than the RF part of Wave 1 base station, it can be used as the RF part of Wave 2 base station with 2T/2R MIMO.

• Journal of the Korean Home Economics Association
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• v.25 no.1
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• pp.83-92
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• 1987

Information on the planning of the housing unit for three generation family is required for developing nuclear families and increasing elderly person. This study deal with the life style, it's characteristics and housing needs of the elderly who lived with other two generations. Specifically, this study attempted to find the basic information of the detailed planning and the establishment of criteria of the housing unit for three generation family. The results of this study were as follows. 1. Planning of the housng unit for three generation family, it had to be taken over residency areas for elderly especially for keeping privacy each other. 2. It was necessary the criteria of housing standards for eldery based on their housing characteristics. 3. Considering the psychological characterstics and life style of the elderly, it should be suggest that they could live easily with their next generation in the samecommunity. Also, the public policy should take over the housing unit for three generation family.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.1
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• pp.1-8
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• 2009

This paper proposes a 24-bit floating point multiply and accumulate(MAC) unit that can be used in geometry transformation process in 3D graphics. The MAC unit is composed of floating point multiplier and floating point accumulator. When separate multiplier and accumulator are used, matrix calculation, used in the transformation process, can't use continuous accumulation values. In the proposed MAC unit the accumulator can get continuous input from the multiplier and the calculation time is reduced. The MAC unit uses about 4,300 gates and can be operated at 150 MHz frequency.

• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.11-17
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• 2012

Along with the recent trend toward increasing variety and shorter life of products in the market, evaluation of risk for economic investment alternatives is of practical importance in manufacturing companies. This paper assumes that each alternative is composed of demand volume and unit sales price as income factors, and unit variable cost and fixed cost as expense factors. The paper assumes that these four factors move worse from the originally expected values, toward the direction of decreasing profit. Values of these four factors are also assumed to fluctuate from year to year over the entire multi-period. By applying the analysis of the breakeven points to each of the four factors, safer area against these changes is represented on the two dimensional domain called normalized total-cost unit-cost domain. A practical numerical example is analyzed to verify the validity of the proposed method.

• Communications for Statistical Applications and Methods
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• v.25 no.1
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• pp.91-97
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• 2018

In this paper, we show that there exists an optimal investment policy for the surplus in a risk model, in which the surplus is continuously invested to other business at a constant rate a > 0, whenever the level of the surplus exceeds a given threshold V > 0. We assign, to the risk model, two costs, the penalty per unit time while the level of the surplus being under V > 0 and the opportunity cost per unit time by keeping a unit amount of the surplus. After calculating the long-run average cost per unit time, we show that there exists an optimal investment rate $a^*$>0 which minimizes the long-run average cost per unit time, when the claim amount follows an exponential distribution.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.1
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• pp.183-193
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• 2024

Recurrent Neural Network technology that learns past patterns and predicts future patterns using technology for recognizing and classifying objects is being applied to various industries, economies, and languages. And research for practical use is making a lot of progress. However, research on the application of Recurrent Neural Networks for evaluating and predicting the safety of mechanical structures is insufficient. Accurate detection of external load applied to the outside is required to evaluate the safety of mechanical structures. Learning of Recurrent Neural Networks for this requires a large amount of load data. This study applied the Gated Recurrent Unit technique to examine the possibility of load learning and investigated the possibility of applying a stacked Auto Encoder as a way to secure load data. In addition, the usefulness of learning mechanical loads was analyzed with the Gated Recurrent Unit technique, and the basic setting of related functions and parameters was proposed to secure accuracy in the recognition and prediction of loads.

• Korean Journal of Microbiology
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• v.43 no.1
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• pp.59-65
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• 2007

The optimal conditions for Monascus pigments production of Monascus sp. KM 1001, pigment overproducing mutant, in submerged culture was investigated. The optimal medium for the production of pigment from KM 1001 mutant is determined to be composed of 4% rice powder, 0.15% Bacto-peptone, 0.1% glycine, 0.01% $FeSO_{4}{\cdot}7H_{2}O,\;0.1%\;MgSO_{4}{\cdot}7H_{2}O,\;0.25%\;KH_{2}PO_{4},\;pH4.5$. On optimal conditions,10.0 g/L of the cell mass was obtained at $30^{\circ}C$ for 5 days. Yellow, orange and red pigment of Monascus sp. KM 1001 were produced 3.25 units, 1.59 units and 0.88 units in extracellular part, and 84.96 units, 78.84 units and 91.80 units in intracellular part, respectively.

• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.695-705
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• 2006

This study was carried out to make a basic information for establishment of countermeasures against water pollution of Hoengseong watershed, accordingly we investigated the characteristics of pollutants discharge and estimated the unit loads from Hoengseong watershed. Seven sites (S1~S7) were selected for sampling and samples were taken 4 times during the dry and rainy seasons, respectively. During rainfall events, measured site mean concentration (SMC) ranges of $BOD_5$, $COD_{Mn}$, TOC, SS, Turbidity, T-N and T-P were 0.8~1.3 mg/L, 2.3~6.3 mg/L, 1.284~2.110 mg/L, 3.4~69.3 mg/L, 2.36~52.68 NTU, 1.243~1.669 mg/L and 0.025~0.070 mg/L, respectively. And the calculated annual unit loads of $BOD_{5}$, $COD_{Mn}$, SS, T-N and T-P in Hoengseong watershed were 1.327 kg/ha/yr, 7.349 kg/ha/yr, 87.075 kg/ha/yr, 1.848 kg/ha/yr and 0.103 kg/ha/yr, respectively. It was difficult to directly compare the unit loads proposed in this study with the estimated existing those. Because the unit loads in this paper were estimated not by land use types, but by complex land use of non-urban area. From the survey results, they showed that the unit loads in Hoengseong watershed were similar to those exisiting in the forest area, and showed lower than those existing in the paddy/dry field.

• The Korean Journal of Applied Statistics
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• v.24 no.2
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• pp.393-400
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• 2011

In a large scale survey, cluster sampling design in which a set of observation units called clusters are selected is often used to satisfy practical restrictions on time and cost. Especially, a two stage cluster sampling design is preferred when a strong intra-class correlation exists among observation units. The sample Primary Sampling Unit(PSU) and Secondary Sampling Unit(SSU) size for a two stage cluster sample is determined by the survey cost and precision of the estimator calculated. For this study, we derive the optimal sample PSU and SSU size when the population SSU size across the PSU are di erent by extending the result obtained under the assumption that all PSU have the same number of SSU. The results on the sample size are then applied to the $4^{th}$ Korea Hospital Discharge results and is compared to the conventional method. We also propose the optimal sample SSU (discharged patients) size for the $7^{th}$ Korea Hospital Discharge Survey.

• Journal of Preventive Medicine and Public Health
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• v.5 no.1
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• pp.9-15
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• 1972

Carbon monoxide poisoning is one of the most serious health problems in Korea, because we have been encountered with the highest incidence of CO poisoning in the world due to the unique heating system in home called 'ondal'. We opened Hyperbaric chamber unit in the Seoul National University Hospital last Jan, 1969. We have treated 848 patients as of Sept. 30., 1972, around 44 months period. We collected the informations on the environmental conditions of the place where CO intoxication actually occured by filling up the questionaire from 505 patients. The following findings were obtained. 1. Age distribution showed that the highest incidence was found in the younger age group between age of 10 to age of 29 in both sex. 2. Sex ratio of the patients was 1:1.14. 3. The socio-economic level of the patient was relatively low. 4. Housewife & housemaid were the major victims of the intoxication in the female patients & in the case of the male patient, occupational backgrounds were diverse. 5. Many patients from the middle class experienced the intoxication by sleeping at newly built room. 6. Many intoxication has been occured in the structure of houses where communicating doors are existing between living room & kitchen. 7. All findings obtained taught us again that CO poisoning is the serious by-product of the national fuel policy which put emphasis on the use of coal & socio-economic status is a very important parameter in this hazards.