• KSBB Journal
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• v.16 no.5
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• pp.516-522
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• 2001

The large-scale production of antibiotics by filamentous mycelial organism requires and adequate supply of dissolved oxygen. In terms of productivity, it means that oxygen transfer is the rate-limiting step. Therefore, the oxygen transfer coefficients(K$\_$L/A) were determined in a broth involving a filamentous mycelial organism such as Streptomyces avermitilis for use in fermentations. To determine (K$\_$L/A) inn a stirred vessel, a great deal of effort is required to provide all the cells with a sufficient oxygen supply. To overcome the oxygen limitation in a batch culture, a fed-batch culture was applied to control the growth rate by an intermittent supply of nutrients. Thus, it was possible to maintain a suitable dissolved oxygen concentration at a low agitation rate. The optimal agitation speed was 350 rpm at low cell concentrations (below 7 g/L) by considering the efficiency of agitation and shear stress. The (K$\_$L/A) was found to decrease from 64.26 to 29.21h.$\^$-1/ when the biomass concentration was increased from 9.82 to 12.06 g/L. In addition, and increase in viscosity was also observed during the growth phase. By comparing the (K$\_$L/A) values for the various agitation and aeration rates, it was found that the effect of an increase in (K$\_$L/A) by aeration was reduced dramatically at high biomass concentrations. However, this effect was not observed when altering the agitation rate. This suggests that controlling the dissolved oxygen concentration by altering the agitation rate was more efficient than increase the aeration rate.

• Journal of Korea Water Resources Association
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• v.32 no.5
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• pp.579-591
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• 1999

The operation of a reservoir system is necessary for establishing the operation rule as well as designing the reservoirs for water resources planning or management. Increasingly complex water resource systems require more advanced operation techniques. As a result, various techniques have been introduced and applied until now. In this study Linear Tracking model based on optimal control theory is applied to the operation of the largest scale multi-reservoir system in the Han river and its applicability proved. This system normally supplies the water resources required downstream for hydro-power and plays a role in satisfying the water demand of the Capital region. For the optimal use of the water resources the Linear Tracking model is designed with the objective to maximize the hydro-power energy subject to the water supply demand. The multi-reservoir system includes the seven main reservoirs in IIan river such as Hwachon, Soyanggang, Chunchon, Uiam, Cheongpyong, Chungju and Paldang. These reservoirs have been monthly operated for the past 21 years. Operation results are analyzed with respect to both hydro"power energy and water supply. Additionally the efficiency of the technique is assessed.sessed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.394-400
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• 2018

Recently, it is expected to significantly increase the defense budget by acquiring large-scale weapons systems to enhance defensive capabilities. In order to secure funds needed to acquire such weapons systems, it is necessary to improve the efficiency of the defense budget. In addition, interest in economic factors affecting the domestic economy such as export opportunities and employment creation are increasing, as well as budget reduction of the defense acquisition business. In order to respond to these demands, this study conducted cost- benefit analysis and examined economic ripple effects in the implementation of defense procurement projects. However, research on economic analysis methodology considering characteristics of defense acquisition projects is still in its early stage. This study proposes a methodology to analyze the economic feasibility of defense acquisition projects and conducted a case study on the economic feasibility of the ${\bigcirc}{\bigcirc}$ guided missile project which is being prepared against local provocation. The proposed economic analysis method provides the cost-effectiveness analysis that has been performed in many weapon system acquisition projects in connection with the more general cost-benefit analysis method. This study contributes to the establishment of an improved theoretical methodology for weapon system acquisition projects.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.3
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• pp.99-107
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• 2013

In this study, field scale test was conducted to estimate the TMDL coefficients (runoff and leachate:(${\beta}4$)(${\beta}5$)(${\beta}8$)) for the livestock resources applying to agricultural crop land as fertilizer, and the results were obtained as follows. Each waste reduction coefficient(${\beta}4$) was shown to be in the range of 0.94~0.75 for public waste treatment plants and 0.99~0.83 for private waste treatment in the analysis of BOD, COD, SS, T-N, T-P, TOC. Thus private plants showed higher rate. Waste treatment discharge into the land coefficient (${\beta}5$) was also shown to be in the range of 0.4.~0.24 for public plants and 0.75~0.16 for private plants, so it is much lower than other coefficients. However SS and T-P were shown to be much higher for land discharge in private plants than in public plants. Treatment coefficient in the public plants (${\beta}8$) appeared to be average 0.75 for T-P but over 90% treatment efficiency and also large deviation were observed due to 0.2 of some other treatment plants.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.9
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• pp.35-46
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• 2011

Future Internet should support more efficient mobility management, flexible traffic engineering and various emerging new services. So, lots of traffic engineering techniques have been suggested and developed, but it's impossible to apply them on the current running commercial Internet. To overcome this problem, OpenFlow protocol was proposed as a technique to control network equipments using network controller with various networking applications. It is a software defined network, so researchers can verify their own traffic engineering techniques by applying them on the controller. In addition, for high-speed packet processing in the OpenFlow network, programmable NetFPGA card with four 1G-interfaces and commercial Procurve OpenFlow switches can be used. In this paper, we implement an OpenFlow test-bed using hardware-accelerated NetFPGA cards and Procurve switches on the KREONET, and implement CSPF (Constraint-based Shortest Path First) algorithm, which is one of popular QoS routing algorithms, and apply it on the large-scale testbed to verify performance and efficiency of multimedia traffic engineering scheme in Future Internet.

• Journal of Korea Technology Innovation Society
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• v.16 no.2
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• pp.476-505
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• 2013

Korea government has established and pursued green technology development strategy as the core of green growth, for example, withdrawal of 27 key green technologies through 'green technology research and development comprehensive plan ('09.1)' since 'low carbon green growth' was proposed as a new national development paradigm. In this study, we performed the Delphi survey of technology levels of 131 strategic product and service technologies derived from 27 key green technologies, utilizing large-scale group of green technology experts. The survey of technology level among main five nations resulted in the world's leading nation (US) versus EU (99.4%), Japan (95.3%), Korea (77.7%), China (67.1%) and Korea was ranked fourth. The technology gap between the world's leading nation (US) and Korea is 4.1 years behind EU (3.9 years) and Japan(3.1 years), but 2.1 years earlier than China. For our nation, key green technologies with high technology level are 'improved light water reactor (90.1%)', 'silicon-based solar cell (85.0%)', 'high-efficiency low-emission car (84.5%)' in order. Depending on the investment type of key green technologies, technology level is represented as short-term (85.0%), mid-term (77.3%) and long-term (71.1%) in order, indicating that lower technology level requires mid-to long-term investment and that the investment type is set appropriate.

• Fire Science and Engineering
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• v.31 no.6
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• pp.40-46
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• 2017

As one of the solutions to deal with economic loss caused by traffic congestion in metropolitan area, a deep underground road has been planned and implemented at home and abroad. The part of them has been pushed ahead with a double-deck scheme which has an advantage in constructability and cost efficiency comparing to traditional road tunnel. However, the double-deck tunnel has a lower floor height than the general road tunnel due to the special structure used as the upper and lower lines by installing the middle slab on one excavation section. Therefore, it is relatively weak against fire accidents and ventilation problems occurring in tunnels. Thus study to develop the life safety system optimized to a double-deck tunnel has been systematically carried out in order to overcome their weak point. In this study, automatic monitoring fire extinguisher (AMFE) is developed to suppress a fire and prevent its spread at early stage of tunnel fire, conducting the performance test through vehicle fire tests as verification. The tests were conducted with AMFE being 30 m apart from the vehicle and 10 m apart from engine room. As a results, it was confirmed that AMFE enables to suppress a fire and prevent its spread in both cases.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.587-599
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• 2023

As climate change increasesthe frequency and risk of flooding in major cities around theworld, the importance ofsimulation technology that can quickly and accurately analyze high-resolution 2D flooding information in large-scale areasis emerging. The physically-based approaches based on the Shallow Water Equations (SWE) often requires huge computer resources hindering high-resolution flood prediction. This study investigated the theoretical background of Weighted Cellular Automata 2D (WCA2D), which simulates spatio-temporal changes offlooding using transition rules and weight-based system, and assessed feasibility to simulate pluvial flooding in the urbancatchment, theOncheon-cheon catchmentinBusan, SouthKorea.Inaddition,the computation performancewas compared by applying versions using OpenComputing Language (OpenCL) andOpenMulti-Processing (OpenMP) parallel computing techniques. Simulationresultsshowed that the maximuminundation depthmap by theWCA2Dmodel cansimilarly reproduce historical inundation maps. Also, it can precisely simulate spatio-temporal changes of flooding extent in the urban catchment with complex topographic characteristics. For computation efficiency, parallel computing schemes, theOpenCLandOpenMP, improved the computation by about 8~14 and 5~6 folds respectively, compared to the sequential computation.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.1
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• pp.135-144
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• 2024

In this study, we propose an automatic classification model for quantitative multidimensional analysis based on facet theory to understand public opinions and demands on major issues through big data analysis. Civil complaints, as a form of public feedback, are generated by various individuals on multiple topics repeatedly and continuously in real-time, which can be challenging for officials to read and analyze efficiently. Specifically, our research introduces a new classification framework that utilizes facet theory and political analysis models to analyze the characteristics of citizen complaints and apply them to the policy-making process. Furthermore, to reduce administrative tasks related to complaint analysis and processing and to facilitate citizen policy participation, we employ deep learning to automatically extract and classify attributes based on the facet analysis framework. The results of this study are expected to provide important insights into understanding and analyzing the characteristics of big data related to citizen complaints, which can pave the way for future research in various fields beyond the public sector, such as education, industry, and healthcare, for quantifying unstructured data and utilizing multidimensional analysis. In practical terms, improving the processing system for large-scale electronic complaints and automation through deep learning can enhance the efficiency and responsiveness of complaint handling, and this approach can also be applied to text data processing in other fields.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.6 no.2
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• pp.45-56
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• 2007

As function and scale of the transit center get larger, the efficient guidance system in the transit center is essential for transit users in order to find their efficient routes. Although there are several studies concerning optimal path for the road, but insufficient studies are executed about optimal path inside the building. Thus, this study is to develop the algorithm about optimal path for car owner from the basement parking lot to user's destination in the transfer station. Based on Dijkstra algorithm which calculate horizontal distance, several factors such as fatigue, freshness, preference, and required time in using moving devices are objectively computed through rank-sum and arithmetic-sum method. Moreover, optimal public transportation is provided for transferrer in the transfer station by Neuro-Fuzzy model which is reflected on people's tendency about public transportation mode choice. Lastly, some scenarios demonstrate the efficiency of optimal path algorithm for pedestrian in this study. As a result of verification the case through the model developed in this study is 75 % more effective in the scenario reflected on different vertical distance, and $24.5\;{\sim}\;107.7\;%$ more effective in the scenario considering different horizontal distance, respectively.