• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.817-823
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• 2023

Manufacturing plants face the challenge of reducing energy use in response to climate change. Reducing energy consumption can be seen as one of the most important issues, such as reducing production costs and improving efficiency. Among manufacturing industries, the increase in energy consumption in the food industry is gradually increasing along with the improvement of the standard of living and the increase in population. In order to save energy in food processing plants, it is important to identify and analyze energy consumption characteristics in energy-consuming processes. Prior to this, it is necessary to monitor and analyze existing energy consumption to derive reduction measures. In this study, a small and medium-sized food processing plant producing processed meat products was used as a case study to identify and analyze the energy consumption structure at typical cycle/stage level of the batch heating process. From this, we tried to establish realistic and quantitative goals that can be obtained under individual process operating conditions. The results of this study will be used as basic data for the development of diffusion and pervasive energy saving FEMS technology for common core processes of food factories of small and medium-sized enterprises in the future.

• Journal of Practical Agriculture & Fisheries Research
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• v.17 no.1
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• pp.163-179
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• 2015

The aim of this study is to investigate to which degree farmers did the crop switching and cultivar renewal as a confrontational strategy to climate change, and which problems they had in that process, and then to provide the supporting plans for them. We conducted a questionnaire survey of 15 citrus farmers of the KNCAP graduates in Jeju Island. Most of the survey respondents agreed to the climate change of Jeju Island and the subtropical climate of its coastal area. The farmers have experienced irregular weather such as abnormal high temperature, frequent rain, and droughts, resulting in the harmful insects and new weeds attack. As the climate change strategies, they are adopting a greenhouse culture system, improving a soil drainage using reorganization of planting space, making a new pest management program, and trying to switch a crop to subtropical fruits. It is expected that 50% of the survey respondents have changed their crops or will do; and 73 % of them have changed cultivar or have a plan to do. Only a few farmers directly pointed to a reason for their efforts to change the crops or to renew the cultivars as the anti-climate change strategy, however, most farmers answered the reason was to increase profitability by meeting their consumers' tastes. Presently, it is not the anti-climate change strategy but increase of profitability by meeting the consumers' needs the reason why most of the survey respondents have changed their crops or renewed the cultivars, while a few of them switched their crops to a subtropical fruit trees due to climate change. On the crop switching, they had some difficulties such as a labor shortage, availability of land, operating costs and instable income. On the cultivar renewal, also, they encountered the lack of cultivating techniques for new cultivars and the dim future for the new market. In long-term perspective, Jeju's farmers need new information and educational programs about the effect of climate change on agriculture of Jeju, and cultivation techniques for new crops and new cultivars.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.327-328
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• 2022

The recent spread of the corona pandemic and a temporary surge in demand for consumer goods have resulted in an increase in port cargo volume, and the resulting port congestion is coupled with a shortage of labor in the port, exacerbating the global supply chain chaos. Supply chain disruptions will increase logistics costs and ultimately increase global inflationary pressures. In this situation, the role of the port, which is the nodal point between land and sea, is gradually becoming more important. And fully automated ports that are operated unmanned are evaluated as being able to respond stably and flexibly by reducing operational risks in situations such as COVID-19. Therefore, this study compared the operational performance of fully automated and non-fully automated terminals within the same port before and after the corona outbreak, and analyzed the fully automated terminal was stable in actual operation. As a result of the analysis, the fully automated terminal showed stable operating efficiency in all aspects of operational performance compared to the non-fully automated terminal even under severe port congestion due to COVID-19.

• Journal of Industrial Convergence
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• v.21 no.11
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• pp.13-27
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• 2023

This study aims to contribute to the reduction of the failure rate and social costs resulting from business failures by analyzing factors that affect the insolvency of social enterprises, as the role of social enterprises is increasing in our economy. The data used in this study were classified as normal and insolvent companies among social enterprises (including prospective social enterprises) that were established between 2009 and 2018 and received credit guarantees from credit guarantee institutions as of the end of June 2022. Among the collected data, 439 social enterprises with available financial information were targeted; 406 (92.5%) were normal enterprises, and 33 (7.5%) were insolvent enterprises. Through a literature review, eight non-financial factors commonly used for insolvency prediction were selected. The cross-analysis results showed that four of these factors were significant. Logistic regression analysis revealed that two variables, including corporate credit rating and the personal credit rating of the representative, were significant. Financial factors such as debt ratio, sales operating profit rate, and total asset turnover were used as control variables. The empirical analysis confirmed that the two independent variables maintained their influence even after controlling for financial factors. Given that government-led support and development policies have limitations, there is a need to shift policy direction so that various companies aspiring to create social value can enter the social enterprise sector through private and regional initiatives. This would enable the social economy to create an environment where local residents can collaborate to realize social value, and the government should actively support this.

• Composites Research
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• v.36 no.6
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• pp.454-460
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• 2023

Recently, regulations on greenhouse gas emissions have been strengthened, and the International Maritime Organization (IMO) has been strengthening greenhouse gas regulations with a goal of net 'zero' emissions by 2050. In addition, in the shipbuilding/offshore sector, it is important to reduce operating costs, such as improving propulsion efficiency and lightening structures. In this regard, research is currently being conducted on topology optimization using 3D printed composite materials to satisfy structural lightness and high rigidity. In this study, three topology shapes (hexagonal, square, and triangular) were applied to the interior of a rudder, a ship structure, using 3D printed composite materials. Structural analysis was performed to determine the appropriate shape for the rudder. CFD analysis was performed at 10° intervals from 0° to 30° for each rudder angle under the condition of 8 knots, and the load conditions were set based on the CFD analysis results. As a result of the structural analysis considering the internal topology shape of the rudder, it was confirmed that the triangular, square, and hexagonal topology shapes have excellent performance. The rudder with a square topology shape weighs 78.5% of the rudder with a triangular shape, and the square topology shape is considered to superior in terms of weight reduction.

• Journal of Korea Port Economic Association
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• v.39 no.4
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• pp.43-65
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• 2023

Recently, with the increasing international interest on environmental issues, efforts have been made to reduce greenhouse gas emissions due to ship fuel, however, the dependence on fossil fuel is expected to continue for a while. Since fuel costs account for a high portion of the total operating cost of a ship, it is necessary to analyze the influence of oil prices on the shipping markets. The purpose of this study is to evaluate the relationship between the international oil prices and the four major shipping markets for bulk carriers. This study employed WTI as the oil price variable while monthly data from 2017 to 2020 from the four major shipping markets by classifying freight rates, charter rates, newbuilding prices, and secondhand prices were also considered in multiple ship sizes of capesize, panamax, supramax, and handysize. Firstly, the results of the correlation analysis using the VAR model indicate that changes in international oil prices have a statistically positive (+) significant effect on BCIS only in the second time lag, on BSIS at all lags, and on BHIS only in the first staggered period. Secondly, as a result of correlation analysis using the VECM model, in the case of BPIC, BHIC, BCIN, and BHIR, the cointegration coefficient value has a negative (-) significant effect at the 5% significance level in the cointegration relationship with international oil prices. Further, in the case of the dynamic correlation, the increase in oil price in the first period of the lag leads to a decrease in the BCIN newbuilding prices while the increase in the oil price in the first and second period in the lag leads to a decrease in the BHIR used ship prices.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.212-221
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• 2011

Wastewater treatment plants (WWTPs) are required to meet the reinforced discharge standards which are differentiated as 0.2, 0.3 and 0.5 mg-TP/L for the district I, II and III, respectively. Although most of WWTPs are operating advanced biological phosphorus removal system, the supplementary phosphorus treatment facility using chemical addition should be required almost at all WWTPs. Therefore, water quality data from several exemplary full-scale plants operating phosphorus treatment process were analyzed to evaluate the reliability of removal performance. Additionally, a series of jar tests were conducted to find optimal coagulants dose for phosphorus removal by chemical precipitation and to describe characteristics of the reaction and sludge production. Chemical costs and the increasing sludge volume in physicochemical phosphorus removal process were estimated based on the results of jar tests. The minimum coagulant (aluminium sulfate and poly aluminium chloride) doses to keep TP concentration below 0.5 and 0.2 mg/L were around 25 and 30 mg/L (as $Al_2O_3$), respectively, in the mixed liquor of activated sludge. In the tertiary treatment facility, relatively lower coagulant doses of 1/12~1/3 the minimum doses for activated sludge were required to achieve the same TP concentrations of 0.2~0.5 mg/L. Increase in suspended solids concentration due to chemical precipitates in mixed liquor was estimated at 10~11%, compared to the concentration without chemical addition. When coagulant was added into mixed liquor, chemical (aluminium sulfate) cost was estimated to be 4~10 times higher than in secondary effluent coagulation/separation process. Sludge production to be wasted was also 4~10 times higher than secondary effluent coagulation/separation process.

• Environmental and Resource Economics Review
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• v.14 no.4
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• pp.817-838
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• 2005

In this paper, the resource adequacy as well as the optimum fuel mix is obtained by the following procedures. First, the regulation body, the government agency, determine the reliability index as well as the optimum portfolio of the fuel mix during the planning horizon. Here, the resources with the characteristics of public goods such as demand-side management, renewable resources are assigned in advance. Also, the optimum portfolio is determined by reflecting the economics, environmental characteristics, public acceptance, regional supply and demand, etc. Second, the government announces the required amount of each fuel-type new resources during the planning horizon and the market participants bid to the government based on their own estimated fixed cost. Here, the government announces the winners of the each auction by plant type and the guaranteed fixed cost is determined by the marginal auction price by plant type. Third, the energy market is run and the surplus of each plant except their cost (guaranteed fixed cost and operating cost) is withdrew by the regulatory body. Here, to induce the generators to reduce their operating cost some incentives for each generator is given based on their performance. The performance is determined by the mechanism of the performance-based regulation (PBR). Here the free-riding performance should be subtracted to guarantee the transparent competition. Although the suggested mechanism looks like very regulated one, it provides two mechanism of the competition. That is, one is in the resource construction auction and the other is in the energy spot market. Also the advantages of the proposed method are it guarantee the proper resource adequacy as well as the desired fuel mix. However, this mechanism should be sustained during the transient period of the deregulation only. Therefore, generation resource planning procedure and market mechanisms are suggested to minimize possible stranded costs.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.514-520
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• 2014

In this study, the production potential of alternative coagulant ($Al_2(SO_4)_3$ solution) having the identical coagulation activity with respect to the commercial coagulant was investigated. The raw material of alternative coagulant was a spent catalyst including aluminium (waste activated alumina) generated in the manufacturing process of the polymer. The alternative coagulant was produced through a series of processes: 1) intense heat and grinding, 2) chemical polymerization and substitution with $H_2SO_4$ solution, 3) dissolution and dilution and 4) settling and separation. To determine the optimal operating conditions in the lab-scale autoclave and dissolver, the content of $Al_2O_3$ in alternative coagulant was analyzed according to changes of the purity of sulfuric acid, reaction temperature, injection ratio of sulfuric acid and water in the dissolver. The results showed that the alternative coagulant having the $Al_2O_3$ content of 7~8% was produced under the optimal conditions such as $H_2SO_4$ purity of 50%, reaction temperature of $120^{\circ}C$, injection ratio of $H_2SO_4$ of 5 times and injection ratio of water of 2.3 times in dissolver. In order to evaluate the coagulation activity of the alternative coagulant, the Jar-test was conducted to the effluent in aerobic reactor. As a result, in both cases of Al/P mole of 1.5 and 2.0, the coagulation activity of the alternative coagulant was higher than that of the existing commercial coagulant. When the production costs were compared between the alternative and commercial coagulant through economic analysis, the production cost reduction of about 50% was available in the case of the alternative coagulant. In addition, it was identified that the alternative coagulant could be applied at field wastewater treatment plant without environmental problem through ecological toxicity testing.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.2
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• pp.109-116
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• 2014

In this study, the factors affecting the profitability of the oriental medicine hospitals of University to be analyzed. To do this, profitability indicators and current ratio, liquidity, turnover ratio, cost factors analysis and suggested ways to improve management. The results are as follows, the operating margin(1.17%). the return on assets(3.76%), the net profit to gross revenues(2.37%), and the net profit to total assets(-1.89) were lower than the average of the entire oriental medicine hospitals in Korea(respectively 8.9%, 8.7%, 2.6%, 2.5%). Current ratio(256.76%), quick ratio(231.17%), fixed ratio(121.02%), and total assets turnover(135.69%) were similar to the average of all oriental medicine hospitals in Korea. But growth rate of total assets(-2.21%), and growth rate of patient revenue(1.89%) is low. And salaries(53.39%), materials costs(16.62%), administrative expenses(28.58%) were different to the average of all oriental medicine hospitals in Korea(respectively 35.3%, 10.7%, 45.1%). Meanwhile, the cost ratio of the oriental medicine hospitals of University was 98.59%. It was 7.49% higher than the 91.1% of the average of all oriental medicine hospitals in 2011. Correlation analysis, growth rate of patient revenue and operating margin increased at the same time, and net profit to gross revenues and net profit to total assets with a growth rate of total assets increased. And administrative expenses and profitability indicators showed a negative correlation. It means, in order to improve the profitability of the oriental medicine hospitals of University should focus on reducing administrative expenses. Multiple regression analysis, growth rate of total assets, total assets turnover, administrative expenses, and salaries has affected the profitability. Therefore, in order to improve the profitability of the oriental medicine hospitals of University to increase the total capital and the total capital turnover, and to reduce administrative expenses effort.