• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.3
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• pp.49-59
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• 1985

Formulation of the geometric optimization for truss structures based on the elasticity theory turn out to be the nonlinear programming problem which has to deal with the Cross sectional area of the member and the coordinates of its nodes simultaneously. A few techniques have been proposed and adopted for the analysis of this nonlinear programming problem for the time being. These techniques, however, bear some limitations on truss shapes loading conditions and design criteria for the practical application to real structures. A generalized algorithm for the geometric optimization of the truss structures which can eliminate the above mentioned limitations, is developed in this study. The algorithm developed utilizes the two-phases technique. In the first phase, the cross sectional area of the truss member is optimized by transforming the nonlinear problem into SUMT, and solving SUMT utilizing the modified Newton-Raphson method. In the second phase, the geometric shape is optimized utilizing the unidirctional search technique of the Rosenbrock method which make it possible to minimize only the objective function. The algorithm developed in this study is numerically tested for several truss structures with various shapes, loading conditions and design criteria, and compared with the results of the other algorithms to examme its applicability and stability. The numerical comparisons show that the two-phases algorithm developed in this study is safely applicable to any design criteria, and the convergency rate is very fast and stable compared with other iteration methods for the geometric optimization of truss structures.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.8
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• pp.870-876
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• 2005

The multiple regression models which have two factors(population and commercial area) have been used to forecast the water demand in the future. But, the coefficient of population had a negative value because proper regional classification wasn't performed, and it is not reasonable because the population must be a positive factor. So, the regional classification was performed by principal component and cluster analysis to solve the problem. 6 regional characters were transformed into 4 principal components, and the areas were divided into two groups according to cluster analysis which had 4 principal components. The new regression models were made by each group, and the problem was solved. And, the future water demands were estimated by three scenarios(Active, moderate, and passive one). The increase of water demand ore $89.034\;m^3/day$ in active plat $49,077\;m^3/day$ in moderate plan, and $19,996\;m^3/day$ in passive plan. The water supply ability as scenarios is enough in water treatment plant, however, 2 reservoirs among 4 reservoirs don't have enough retention time in all scenarios.

• Korean Security Journal
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• no.20
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• pp.313-338
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• 2009

Yet this study of a private security company guards who did not apply to most firms - An exchange relationship with the quality of the application of the theory of private security companies and the high turnover and low job satisfaction and find ways to improve the firm - An exchange relationship Job satisfaction and turnover of the quality of the major research variables with a theoretical discussion of the relationship they set and based on this study demonstrate the analysis is attempted. This expansion contributes to the possibility of applying the theory, and private security companies to manage their organizations more effective by presenting the theoretical basis. Was trying to contribute to practical. Therefore, in this study to determine the following three things that it first, in a private security company bosses - men exchange turnover of the members of the quality of the relationship is to help the relationship, secondly, from a private security company boss - An exchange relationship The quality of the work of the members are satisfied with the relationship, and finally the 'private security company's turnover in the member's job satisfaction is associated with a reduction of is whether. To this end, Seoul. Gyeonggi Province located in a private security guard companies and 238 people involved in the actual target and try to analyze these results demonstrate the firm - An exchange relationship to the quality of the turnover of the direct impact of the factors, but showed up as non - Job satisfaction showed a significant impact. Job satisfaction also significantly affect the turnover of the firm - An exchange relationship to the quality parameters according to degree of turnover. Therefore, exchange relationships with men from private security companies want to increase the quality of the firm's efforts to improve the men's job satisfaction indirectly through a reduction in turnover can be affected have been identified. We in the private security company to members of the firm's position in relation to their subordinates to improve the quality of the proposal is to.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.77-101
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• 2009

Organic farming in Korea has mainly focused on producing vegetables in plastic film house and cereals in paddy field. For high productivity of vegetables and cereals, most Korean farmers have not applied crop rotation in the cropping system. Thus, this study was carried out to evaluate the effects of crop rotation on the yield of red pepper and green onion, the changes in soil fertility and the potential as green manure of rye and hairy vetch. Rye and hairy vetch were cultivated for winter season every year, and directly incorporated into the soil. The yield of red pepper fruits in organic farming using crop rotation (OFCR) decreased 23 to 36% compared with conventional farming system (CFS). Whereas, green onion showed the increased yield of about 13%. In OFCR, total carbon content of soil was higher, however available phosphate content lower than conventional farming. As a result of measuring the bulk density of soil, OFCR and CFS were 1.26 to $1.35Mg/m^3$ and 1.37 to $1.42Mg/m^3$, respectively. Carbon and nitrogen contents of microbial biomass in OFCR were obviously higher compared with the CFS. In the plot cultivated rye for winter season, the weed germination was strongly reduced (about 52 %). Balance of macro nutrient elements, nitrogen and phosphate, in the application of rye and hairy vetch had a minus value. For potassium, the output value was higher than the input one, therefore organic farming under red pepper-rye or hairy vetch systems requires applying additional potassium input. Also, we selected two hairy vetch varieties of cv. Hungvillosa and Ostsaat which can be adapt at Korea climate. In order to estimate a yield of green manures, the weight of shoot and root was measured. The ratio of shoot and root between rye and hairy vetch showed 0.88 and 1.91, respectively. The potential levels of nitrogen, phosphate and potassium which could be supplied from rye were 7.7, 7.8 and 21.9 kg/10a and from hairy vetch were 17.0, 8.6 and 22.9 kg/10a, respectively. So we recommend that cultivating hairy vetch, as a nutrient supplier, and rye, as an amendment to enhance the soil physical property, for winter season be practical method in Korea organic farming system.

• The Korean Journal of Mycology
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• v.20 no.4
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• pp.337-346
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• 1992

Trichoderma spp. are an effective control agent for damping-off or other plant diseases. The interaction between. T. hamatum and Rhizoctonia solani on the rhizosphere or surface soil were examined to assess the possible roles of antibiosis or competition in the mechanisms of biological control agents as a basic research. In a proportional comparison, total bacteria, fungi, actinomycetes and Trichoderma spp were 65%, 8.8%, 25.9% and 0.28% respectively in their distribution in the soil. Among Trichoderma spp isolated, the 5 species of Trichoderma spp were indentified as T. koninggii, T. pseudokoninggii, T. aureoviridi, T. hamatum and T. viride respectively. In a mycoparasitic test, one isolate of T. hamatum strain Tr-5 showed an enzymatic ability to break fungal hyphae into piecies and infected on the R. solani hyphae showing a parasitism. Spore germination of the all isolates of Trichoderma spp showed a 1.7-7.3% of germination in natural soil conditions, but the percentage was high in sterile soil indicating all the natural soil were fungistatic on conidia of Trichoderma spp. In rhizosphere competent assay in pea plant, the antagonistic T. hamatum, T. viride, T. koninggii, T. pseudokoninggii showed a colonizing upper soil depth in rhizosphere around 1-3 cm in root zone, but the colonizing ability was much reduced along the deeper the soil depth. Propagule density was decreased in deeper the soil layer. Disease development rate treated alone with plant pathogens, Fusarium solani, Rhizoctonia solani, Cylindrocarpon destructans increased, but disease incidence rate reduced in treatment with combinations with antagonistic T. hamatum strain Tr-5.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.625-634
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• 2004

The objective of this experiment is to study the possibility of lactate dehydrogenase(LDH) enzyme to prevent lactate accumulation in the rumen, For understanding capacity of bacterial LDH in rumen environments, this study was conducted to explore the effects of temperature, pH, VFAs and metal ions on Lactobacillus sp. FFy111-1's LDH activity, and the LDH activation in rumen fluid accumulated lactate. The optimum pH and temperature of LDH were pH 7.5 and 40$^{\circ}C$, respectively. The LDH activity had a good thennostability at range from 30 to 50$^{\circ}C$. The highest pH stability of the enzyme was at ranges from pH 7.0 to 8.0 and the enzyme activities showed above 64% level of non-treated one at pH 6.0 and 6.5. The LDH was inactivated by VFAs treatments but was enhanced by metal ion treatments without NaCl and $CuSO_4$ Especially, the LDH activity was increased to 127% and 124% of its original activity by 2 mM of $BaCl_2$ and $MnSO_4$, addition, respectively. When the acidic rumen fluid was treated by LDH enzyme of Lactobacillus sp. FFy111-1, the lactate concentration in the rumen fluid was lower compared with non-treated rumen fluid(P<0.05). This lactate reduction was resulted from an action of LDH. It was proved by result of purified D,L-LDH addition that showed the lowest lactate concentration among the treatments(P<0.05). Although further investigation of microbial LDH and ruminal lactate is needed, these findings suggest that the bacterial LDH has the potential capability to decrease the lactate accumulated in an acidic rumen fluid. Also, screening of super LDH producing bacteria and technical development for improving enzyme activity in rumen environment are essential keys for practical application.

• The Korean Journal of Mycology
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• v.3 no.1
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• pp.1-19
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• 1975

Since the importance of casing in fruit body formation of Agaricus bisporus has been emphasized, physico-chemical characteristics of casing materials were discussed by many workers and a mixture of peat and mineral soil as proper casing material has been adopted in many of mushroom growing countries. Because of limited resources of peat in Korea, it is necessary to find practical performance and substitutional materials for casing. The effect of casing on mycelial growth and mushroom yield of A. bisporus varied with materials, its combination and practices etc. The experiments to be discussed in this paper are concerned with pH and Ca of casing material which influence A bisporus, and changes of physico-chemical characteristics with mixing ratio of casing materials and its effect on A. bisporus. The optimum range of moisture content of each material, management of watering and application of physico-chemical characteristics casing materials was also investigated and re-use of weathered spent compost for casing material was described. 1. The effect of calcium on mycelial growth of A. bisporus at various pH in Halbschalentest showed different results with calcium sources. Best results were obtained around neutrality and fresh weight of fruit bodies grown in the range of pH 7 to 8 was highest among the tested levels. 2. Available moisture, pore space, organic matter, cation exchangeable capacity and exchangeable cation was increased by an increase of mixing ratio of peat in casing materials, while an adverse effect was obtained by addition of sand. 3. Mycelial growth on clay loam was more rapid at a lower bulk density of 0.75g/cc and at 20% moisture content on a dry weight basis at the same bulk density. 4. Mixing ratio of casing materials, 60 to 80 per cent by volume of peat mixed with 20 to 40 per cent of clay loam produced the highest yield of fresh fruit bodies and sand the lowest. However, per cent of open cap was highest in peat and lowest in sand. 5. Days required for fruit body initiation was shortened in mixtures of peat and clay loam by one to three days compared with other materials and the formation of flushes was clear. 6. The effect of some physico-chemical characteristics of casing materials on the fresh weight of fruit bodies were estimated by a multiple regression equation; Y=-923.86+$8.18X_1+8.04X_2+7.90X_3+0.12X_4+2.03X_5-0.82X_6-0.54X_7$ where $X_1,X_2,X_3,X_4,X_5,X_6,X_7$ are sand, silt, clay, available moistuer, porosity, organic matter and exchangeable cation respectively. The productivity of certain casing material could be predicted from this equation. 7. Fresh weight of fruit bodies was positively correlated with porosity exchangeable cation, organic matter, available moisture, silt and clay of materials; while sand was negatively correlated. On the contrary, sand was the unique factor reducing per cent of open cap. 8. Distribution of three phases of high productive casing material was concentrated in the range of 10 to 30 per cent solids, 15 to 30 per cent liquids, and 50 to 60 per cent in air volume. 9. Fresh weight of fruit bodies from peat was not affected with heavy watering but in clay loam and sandy loam severe crop losses occurred. Fresh weight of individual fruit was increased and open caps were decreased with heavy watering but light watering resulted in adverse effects: its effect was especially great in peat. 10. Optimum range of moisture content by weight on a dry basis was different with each casing material. To maintain optimum moisture content concerned with yield of fruit bodies and open cap, sandy loam and peat mixtures required daily watering of 0.6, 0.6 to 1. 2 and 1.2 to 2.4 liters per $3.3m^2$ of bed area, respectively. 11. Maximum yield of fruit body was recorded in the range of pF 2. 0 to 2. 5 of casing materials if organic matter content was below 4.2 per cent and in pF 1. 3 to 1.8 if above 7.1%. 12. pF curve of a certain casing material could be draws from moisture content at various pF values by multiple regression equations provided texture, organic matter and calcium of the casing material are given. Optimum moisture range of the casing materials also could be estimated by the equation. 13. It was possible to improve the phyico-chemical characteristics of clay loam and sandy loam by addition of weathered spent compost although the effect was less than in the case of peat. Fresh weight of fruit bodies wsa increased by addition of weathered spent compost but its effect was not as remarkable as peat. Accordingly, further studies will be required.

• Journal of Korean Society of Forest Science
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• v.77 no.3
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• pp.294-302
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• 1988

The experiment was carried out to investigate the properties of bark extractives form Larix epilepsies and to evacuate their suitability as a bonding agent. The yield and reactivity were measured to examine the influence of temperature and time and the effect of carbonation and sulfonation. To define the possibility of practical application as wood adhesives the viscosity and gelation time were measured at 33% concentration. The results obtained were summarized as follows : 1. As the both yield and reactivity were high, extraction for 2 hours at $80^{\circ}C$ was the optimal temperature and time. 2. The highest effect achieved at 1% $Na_2CO_3$ about carbonation and 1% $Na_2SO_3$ : $NaHSO_3$ and 0.25% $Na_2SO_3$ about sulfonation. The sulfonation of 0.25% $Na_2SO_3$ increased the yield and reactivity most highly. 3. By using hot water as extraction liquid the yield was 17.2%, while the addition of 1% and 5% NaOH to the extraction liquid increased the yield to 38.6% and 44.6%, respectively. 4. Hot water extracts showed the highest reactivity(68.8%). The addition of 1% and 5% NaOH led to decrease in reactivity(49.3% and 25.8%, respectively). 5. At 33% concentration of the extracts the viscosity appeared very variable. Significantly high values of viscosity was measured in 1% NaOH solution, while very low values appeared for 5% NaOH solution. 6. The shortest gelation time was determined at pH 7 to 10 and the highest at pH 4. The use of paraformaldehyde resulted in gelation times longer than those of 37% formaldehyde solution. 7. Except the sulfonation extracts of hot water and 1% NaOH, the other extracts were found unsuitable due to high viscosity(1% NaOH extracts, sulfonation extracts) or to curing inability(5% NaOH extracts, sulfonation extracts of 5% NaOH). 8. From the three extract solutions which appeared to be suitable for use as bonding agents the hot water extracts and the sulfonation extracts of hot water were superior in extract reactivity, while the sulfonation extracts of 1% NaOH exceeded the other two extracts in extract yield.

• Management & Information Systems Review
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• v.31 no.3
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• pp.223-248
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• 2012

This study analyses support policy and structural change of textile industry in Daegu Kyungbuk region, and suggests major issues for textile industry's innovation. In Daegu Kyungbuk, it was 1999 that a policy, so called Milano Project, in order to promote a textile industry was devised. In 2004, the Regional Industrial Promotion Plan was devised. The plan was born from a view point of establishing a regional innovation system and of promoting the innovative clusters under a knowledge based economy. After then, the Regional Industry Promotion Project or Regional Strategic Industry Promotion Project became a core of regional textile industrial policy. Research results indicated that the first stage Milano project (1999-2003) showed both positive and negative effects. There were no long-term development plan, clear vision and strategy. But, core industrial infrastructure for differentiated product development, such as New product Development Support Center and Dyeing Design Practical Application Center, was constructed. The second stage Daegu Textile Industry Promotion Plan (2004-2008) displayed a significant technological performance and new product sales with the assistance of Kyungbuk province. Also, textile industry revealed positive fruits such as financial structure, productivity, and profitability as a result of strong restructuring. In industrial structure, there was a important change from clothe textile material to industry textile material. Most of textile companies did not showed high capability in CEO's technology innovation intention, entrepreneurship, R&D and human resource competency in compare with other industry. We suggested that Daegu Kyungbuk has to select and concentrate on the high-tech textile material and living textile for sustainable development and competitiveness. We also proposed a confidence and cooperation based innovation network and company oriented innovation cluster.

• Geophysics and Geophysical Exploration
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• v.21 no.3
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• pp.150-161
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• 2018

Recently, unmanned aircraft EM (electromagnetic) survey based on ICT (Information and Communication Technology) has been widely utilized because of the efficiency in regional survey. We performed the theoretical study on the unmanned airship EM system developed by KIGAM (Korea Institute of Geoscience and Mineral resources) as part of the practical application of unmanned aircraft EM survey. Since this system has different configurations of transmitting and receiving loops compared to the conventional aircraft EM systems, a new technique is required for the appropriate interpretation of measured responses. Therefore, we proposed a method to calculate the EM field for the arbitrary shaped transmitter and verified its validity through the comparison with analytic solution for circular loop. In addition, to simulate the magnetic responses by three-dimensionally (3D) distributed anomalies, we have adapted our algorithm to 3D frequency-domain EM modeling algorithm based on the edge-FEM (finite element method). Though the analysis on magnetic field responses from a subsurface anomaly, it was found that the response decreases as the depth of the anomaly increases or the flight altitude increases. Also, it was confirmed that the response became smaller as the resistivity of the anomaly increases. However, a nonlinear trend of the out-of-phase component is shown depending on the depth of the anomaly and the used frequency, that makes it difficult to apply simple analysis based on the mapping of the magnitude of the responses and can cause the non-uniqueness problem in calculating the apparent resistivity. Thus, it is a prerequisite to analyze the appropriate frequency band and flight altitude considering the purpose of the survey and the site conditions when conducting a survey using the unmanned aircraft EM system.