• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.45-50
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• 2000

For the maximum production of pullulan from glucose as a carbon source, the effects of glucose concentration, pH and dissolved oxygen concentration on the cell growth and mass production of high-molecular weight pullulan by A. pullulans ATCC 42023 were evaluated. A. pullulans showed optimum pullulan productivity when glucose concentration was 0.3M (54g/L). And inhibitory effects on the cell growth and the pullulan production were observed at the glucose concentration higher than 0.3M (54g/L). The influence of pH control and dissolved oxygen on the pullulan production and growth of A. pullulans was studied. In shake-flasks, maximum pullulan production was obtained with $11.98g/{\ell}$ when initial pH was 6.5. In the batch fermentation, the maximum pullulan production of $13.31g/{\ell}$ was obtained with constant pH 4.5. And it was found that pullulan yield and synthesis rate increased with oxygen availability. For the production of commercially useful pullulan with high-molecular weight, a mixed carbon source, which was a mixture of glucose and glucosamine, was used for the pullulan fermentation with A. pullulans. On the basis of 5% mixed carbon source, culture with 3% glucosamine with 2% glucose was optimum condition for the production of high (M.W.> 1,000,000) and medium (M.W.> 200,000) molecular weight pullulan with considerable yields of cell mass and product. And the influence of pH control on the molecular weight of pullulan was studied in batch fermentation. It was found that the productivity of high-molecular weight pullulan with pH control at 6.5 was higher than that with no pH control.

• Journal of Korean Port Research
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• v.11 no.1
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• pp.85-99
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• 1997

The improvements of berth productivity is closely related to berth/port systems and its relationship extends to the overall pattern of port development/logistics, transport and trade. Since ports in general and berths in specific function as a bridge transferring seaborne cargoes from seaside to landside and vice versa, berth productivity improvements should be considered in terms of the total system in which the cargoes are transported from origin to destination via berths/ports. In that respect, the objective of this study is to improve berth productivity which is a vital factor in the strategic planning in port development and operation and logistics. According to a literature survey on the subject, the contents of the studies have been limited to either a macro-perspective or a micro-perspective which is only a partial solution to the problem. Hence, this limitation requires an integrated approach to find and ultimate solution, which should be considered not separately, but as a whole. The contents and scope of this study cover the improvements of berth productivity in conjunction with strategic planning in port development. efficient operation and logistics from two different viewpoints, macro- and micro-perspective. After that, a combination of these two perspectives is applied to the integrated approach due to lacking a comprehensive perspective from either macro-approach or micro-approach. In reality, a port itself is a complex and dynamic organization. Therefore, a comprehensive insight needs an integrated approach for the long-term national economic development. In this approach, the utmost importance is how to find the bottlenecks and to solve the problems effectively from the beginning stage in port development. In conclusion, derived from the macro- and micro-perspective. the attempt to establish an integrated approach is the merit of this study, which is required as a comprehensive measure since none of the two can be a solution independently. In terms of reinforcing this study, it needs further empirical research due to the restriction of the theoretical method of this paper. Consequently, the reinforced research will be able to enhance the integrated approach on the basis of the conceptual perspective.

• Korean Journal of Ecology and Environment
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• v.41 no.spc
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• pp.21-26
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• 2008

The in situ incubation experiment was carried out using $^{13}C$ tracer to determine primary productivity and fatty acid production rate in the shallow, eutrophic Shingu reservoir on 4th July. Particulate organic matter (POM) accounted for 76% in suspended particulate matter (SPM), and average concentration of chlorophyll-${\alpha}$ was $89{\mu}g\;L^{-1}$ in the euphotic layer. Total amount of chlorophyll-${\alpha}$ (Chl-${alpha}$), primary productivity and Chl-${alpha}$ specific productivity in euphotic layer were 112 mg Chl-${alpha}m^{-2}$, 3.53 g C $m^{-2}\;d^{-1}$, 32mg C mg Chl-${\alpha}^{-1}\;d^{-1}$, respectively. The fatty acid composition in newly produced organic matter and suspended organic matter didn't show any significant difference, demonstrating that autochthonous organic matter should be a major source of POM pool. In addition, the fatty acids of bacterial origin were increased through extracellular release of newly photosynthesized DOC, and closely coupled with bacterial assimilation. This result suggests that organic carbon should be actively cycled through the microbial loop in Shingu reservoir in summer.

• Safety and Health at Work
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• v.8 no.1
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• pp.99-104
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• 2017

Background: Workers laboring in steel industries in tropical settings with high ambient temperatures are subjected to thermally stressful environments that can create well-known risks of heat-related illnesses and limit workers' productivity. Methods: A cross-sectional study undertaken in a steel industry in a city nicknamed "Steel City" in Southern India assessed thermal stress by wet bulb globe temperature (WBGT) and level of dehydration from urine color and urine specific gravity. A structured questionnaire captured self-reported heat-related health symptoms of workers. Results: Some 90% WBGT measurements were higher than recommended threshold limit values ($27.2-41.7^{\circ}C$) for heavy and moderate workloads and radiational heat from processes were very high in blooming-mill/coke-oven ($67.6^{\circ}C$ globe temperature). Widespread heat-related health concerns were prevalent among workers, including excessive sweating, fatigue, and tiredness reported by 50% workers. Productivity loss was significantly reported high in workers with direct heat exposures compared to those with indirect heat exposures ($x^2=26.1258$, degrees of freedom = 1, p < 0.001). Change in urine color was 7.4 times higher among workers exposed to WBGTs above threshold limit values (TLVs). Conclusion: Preliminary evidence shows that high heat exposures and heavy workload adversely affect the workers' health and reduce their work capacities. Health and productivity risks in developing tropical country work settings can be further aggravated by the predicted temperature rise due to climate change, without appropriate interventions. Apart from industries enhancing welfare facilities and designing control interventions, further physiological studies with a seasonal approach and interventional studies are needed to strengthen evidence for developing comprehensive policies to protect workers employed in high heat industries.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.305-312
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• 2018

The crops cultivated and consumed in Korea require specific climate conditions corresponding to their own growth characteristics. This study aims to analyze the relationship between climate change and agricultural productivity. According to growing concern about climate change internationally, many agricultural studies are developing technology to prevent damage from climate change. Before developing technology, we should figure out what kind of crop gets huge damage and how much caused by climate change. In the context of agricultural economics, we can define the reduction of agricultural product yield as a decline in productivity. As a result, this study analyzes the effects of climate change on agricultural productivity using Stochastic Frontier Analysis model. There are several kinds of climate change phenomena that increase the inefficiency of production. In other words, there are several kinds of crops that get negative influence by climate change. The result of this study can be used as basic guideline for producers to prepare for changing weather prior to developing disaster tolerance technology coping actively with special weather report.

• Industry Promotion Research
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• v.9 no.4
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• pp.121-133
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• 2024

This study aimed to evaluate the R&D efficiency of Daejeon Metropolitan City's regional industries and to derive policy implications for enhancing the competitiveness of regional industries. To achieve this, Data Envelopment Analysis (DEA) and Malmquist Productivity Index (MPI) were employed to analyze the efficiency and productivity changes of 16 Decision-Making Units (DMUs) in Daejeon's key industries from 2013 to 2022. The DEA analysis revealed that certain industry groups, such as the Research Industry (2013-2014), Bio Industry (2013-2014), and Metal Industry (2015-2017), demonstrated high efficiency by optimizing resource utilization. These industries were found to effectively maximize outputs by efficiently using resources in their R&D activities. On the other hand, some industries, such as the Knowledge Industry (2013-2014) and Wireless Communication Industry (2015-2017), recorded relatively low efficiency, indicating the need for improvements in resource utilization and operational strategies. The Scale Efficiency (SE) analysis showed that some industries were not operating at an optimal scale. Furthermore, the MPI analysis, which evaluated productivity changes over time, confirmed that technological progress and changes in technical efficiency significantly impacted industry-specific productivity. Efficiency changes over time were recorded as 70.96% (13-'14), 70.317% (15-'17), 68.59% (18-'20), and 76.57% ('21-'22), with a 28.38% improvement potential over ten years.

• Microbiology and Biotechnology Letters
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• v.36 no.1
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• pp.28-33
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• 2008

The expression vector (pWHM3-TR1R2) for sprT gene encoding Streptomyces griseus trypsin (SGT) followed by two regulatory genes, sgtR1 and sgtR2, was introduced into Streptomyces lividans TK24 and Streptomyces griseus IFO 13350. Various media with different compositions were used to maximize the productivity of SGT in the recombinant trains. he SGT productivity was best when the transformant of S. lividans TK24 was cultivated in R2YE medium (0.74 unit/mL) at 5 days of cultivation. C5/L (0.66 unit/mL) medium also gave a good productivity, but Livid (0.08 unit/mL) and NDSK (0.06 unit/mL) yielded poor productivities. S. griseus IFO 13350/pWHM3-TR1R2 produced SGT by 1.518 unit/mL (C5/L), 1.284unit/mL (R2YE),0.932 unit/mL (NDSK), and 0.295 unit/mL (Livid) at 7 days of cultivation, which was much higher than those from S. lividans TK24/TR1R2. The SGT protein was purified from the culture broth of S. griseus IFO 13350/pWHM3-TR1R2 in C5/L to homogeneity via ammonium sulfate fractionation, and CM-sepharose and SP-sepharose column chromatographies. The specific activity of purified SGT was 69,252 unit/mg, and the final purification fold and recovery yield were 6.5 and 1.4%, respectively.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.243-264
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• 2013

Antheraea mylitta Drury is a commercial silk producing forest insect in India and Xanthopimpla pedator Fabricius is its larval-pupal endoparasitoid, which causes pupal mortality that affects seed production. Effects of host plants, rearing season and their interactions on parasitic behaviour of X. pedator were studied here, as influence of these factors on biological success of X. pedator is not known. Seven forest tree species were tested as food plants for A. mylitta, and rate of pupal parasitization in both the rearing seasons were recorded and analysed. Results showed that rearing season and host plants significantly affected the rate of pupal parasitization in both the sexes. Pupal mortality was found significantly higher (14.52%) in second rearing season than the first (2.89%). Likewise, host plants and rearing seasons significantly affected length, diameter, and shell thickness of cocoons in both sexes. Out of all infested pupae, 85.59% were found male, which indicated that X. pedator chooses male spinning larva of A. mylitta for oviposition, but we could not answer satisfactorily the why and how aspect of this sex specific parasitic behaviour of X. pedator. Multiple regression analysis indicated that length and shell thickness of male cocoons are potential predictors for pupal parasitization rate of X. pedator. Based on highest cocoon productivity and lowest pupal mortality, Terminalia alata, T. tomentosa, and T. arjuna were found to be the most suitable host plants for forest based commercial rearing of A. mylitta in tropical forest areas of Uttarakhand state, where it has never been reared earlier. Sex and season specific interaction of X. pedator with its larval-pupal host, A. mylitta is a novel entomological study to find out explanations for some of the unresolved research questions on parasitic behaviour of X. predator that opens a new area for specialised study on male specific parasitization in Ichneumonidae.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.203-207
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• 1998

Fed-batch fermentations with different feeding media were carried out in order to increase the productivity of invertase expression using a recombinant Saccharomyces cerevisiae containing plasmid pRB58. Two batch cultures showed the expression of the SUC2 gene at a low concentration of glucose, suggesting that glucose concentration could be used as a control variable in a fed-batch operation mode. In the fed-batch culture by feeding the basal medium, cell mass and specific invertase activity did not increase much as compared with the simple batch culture. A series of fed-batch cultures revealed that the sucrose-supplemented medium increased cell mass whereas the enriched medium did specific invertase activity. To capitalize on the synergism of the sucrose-supplemented medium and the enriched medium, the sucrose-supplemented enriched medium was used as a feeding medium. The fed-batch culture using this medium resulted in a 2.4-fold increase in cell mass and a 1.9-fold enhancement in specific invertase activity compared with those of the batch culture. The increase in cell mass and specific invertase activity led to a marked increase in total invertase activity, 250U/ml, which was 6.3 times higher than that of the batch culture.

• Korean Journal of Heritage: History & Science
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• v.56 no.3
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• pp.22-44
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• 2023

The subsistence economics of the early Bronze Age has focused on explaining the intensity of agricultural practices without sufficiently taking into account the diversity of production methods that may arise from cultural types or environmental factors. The problem appears to stem from paying insufficient attention to the question whether we should understand the transition from the Neolithic Age to the Bronze Age as continuous or discrete. This has hitherto blocked an avenue to investigate the gradual changes in subsistence resource production methods. Taking as its premise that changes in the production methods of subsistence resources in the Bronze Age have been continuous and gradual, this paper seeks to restore the production patterns of subsistence resources according to the variety of factors that may have influenced the early Bronze Age production method. With diverse cultural patterns and ecological spaces of the early Bronze Age being confirmed, the work of restoring the production methods of subsistence resources in a specific period is difficult to achieve with one or two stand-alone analyses. A more appropriate method would involve separating a number of different aspects related to the production of subsistence resources, analyzing and interpreting each, and in the final stage, synthesizing the analyses. The specific research method employed in this paper checked for compositional differences in stone production tools, functionally categorized according to a variety of factors that have a close relationship with the production of subsistence resources: cultural-environmental factors and cultural patterns, geographical and topographical factors, soil productivity, and size of settlement. The results of the analysis are as follows: for the early Bronze Age production pattern of subsistence resources in the Seoul and Gyeonggi regions, while no substantive differences were observed with respect to cultural type, geographical and topographical location, the results show statistically significant differences in the composition of production tools according to settlement size and soil productivity. Also, with an increasing ratio of settlement size and total production soil, increases in hunting and armoring tools, woodworking tools, and harvesting tools were observed; on the other hand, when it came to the ratio of fishing tools, the opposite relationship was observed. While a correlation between settlement size or crop cultivation productivity and dependence on hunting or farming was expected, the results of the regression analysis show that settlement size and soil productivity ratios do not have mutually significant relationships. The results thus illustrate that patterns of production differ according to a variety of factors, and no single factor is decisive in the adoption of subsistence resource production methods by a specific settlement. Therefore, the paper emphasizes the need to investigate the production patterns of subsistence resources according to the variety of cultural and environmental factors that make up settlements in early Bronze Age society.