• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3682-3694
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• 2022

The expansion of a country's ecological footprint generates resources for economic development. China's import bill and carbon footprint can be reduced by investing in green transportation and energy technologies. A sustainable environment depends on the cessation of climate change; the current study investigates nuclear energy efficiency, economic complexity, air transportation, and industrial improvement for reducing environmental footprint. Using data spanning the years 1983-2016, the dynamic autoregressive distributed lag simulation method has demonstrated the short- and long-term variability in the impact of regressors on the ecological footprint. The study findings revealed that economic complexity in China had been found to have a statistically significant impact on the country's ecological footprint. Moreover, the industrial improvement process is helpful for the ecological footprint in China. In the short term, air travel has a negative impact on the ecological footprint, but this effect diminishes over time. Additionally, energy innovation is negative and substantial both in the short and long run, thus demonstrating its positive role in reducing the ecological footprint. Policy implications can be extracted from a wide range of issues, including economic complexity, industrial improvement, air transportation, energy innovation, and ecological impact to achieve sustainable goals.

• Korean Management Science Review
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• v.28 no.3
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• pp.1-13
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• 2011

Hub-and-spoke transportation network is a powerful and useful network structure that takes full advantage of economies of scale on routes between hubs. In recent studies, the network structure is extended to hybrid hub-andspoke that allows direct transportation between spokes. In this study, we considered more extended network structure which is called hybrid multiple hub-and-spoke that has multiple hubs and allows direct transportation between spokes. We developed a mathematical optimization model for automotive service parts transportation planning under hybrid multiple hub-and-spoke network structure. The model suggests a long-term transportation route planning and a short-term vehicle assignment planning. The model is verified by simulation and validated in real world application to Hyundai Mobis automotive service parts transportation planning. From the simulation result, the model reduced the transportation cost about 24.7%, the total distance about 6.8% and the CO2 emissions about 8.8%. In real world application for 6 months from July to December 2010, the model reduced the transportation cost about 9.1% by changing the long-term transportation route without daily vehicle assignment planning.

• Journal of the Korea Society of Computer and Information
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• v.22 no.12
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• pp.49-54
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• 2017

Pathfinding for pedestrians provided by various navigation programs is based on a shortest path search algorithm. There is no big difference in their guide results, which makes the path quality more important. Multiple criteria should be included in the search cost to calculate the path quality, which is called a multi-criteria pathfinding. In this paper we propose a user adaptive pathfinding algorithm in which the cost function for a multi-criteria pathfinding is defined as a weighted sum of multiple criteria and the weights are learned automatically by Perceptron learning. Weight learning is implemented in two ways: short-term weight learning that reflects weight changes in real time as the user moves and long-term weight learning that updates the weights by the average value of the entire path after completing the movement. We use the weight update method with momentum for long-term weight learning, so that learning speed is improved and the learned weight can be stabilized. The proposed method is implemented as an app and is applied to various movement situations. The results show that customized pathfinding based on user preference can be obtained.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.535-543
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• 2019

Building on/with expansive soils with no treatment brings complications. Compacted expansive soils specifically fall short in satisfying the minimum requirements for transport embankment infrastructures, requiring the adoption of hauled virgin mineral aggregates or a sustainable alternative. Use of hauled aggregates comes at a high carbon and economical cost. On average, every 9m high embankment built with quarried/hauled soils cost $12600MJ.m^{-2}$ Embodied Energy (EE). A prospect of using mixed cutting-arising expansive soils with industrial/domestic wastes can reduce the carbon cost and ease the pressure on landfills. The widespread use of recycled materials has been extensively limited due to concerns over their long-term performance, generally low shear strength and stiffness. In this contribution, hydromechanical properties of a waste tyre sand-sized rubber (a mixture of polybutadiene, polyisoprene, elastomers, and styrene-butadiene) and expansive silt is studied, allowing the short- and long-term behaviour of optimum compacted composites to be better established. The inclusion of tyre shred substantially decreased the swelling potential/pressure and modestly lowered the compression index. Silt-Tyre powder replacement lowered the bulk density, allowing construction of lighter reinforced earth structures. The shear strength and stiffness decreased on addition of tyre powder, yet the contribution of matric suction to the shear strength remained constant for tyre shred contents up to 20%. Reinforced soils adopted a ductile post-peak plastic behaviour with enhanced failure strain, offering the opportunity to build more flexible subgrades as recommended for expansive soils. Residual water content and tyre shred content are directly correlated; tyre-reinforced silt showed a greater capacity of water storage (than natural silts) and hence a sustainable solution to waterlogging and surficial flooding particularly in urban settings. Crushed fine tyre shred mixed with expansive silts/sands at 15 to 20 wt% appear to offer the maximum reduction in swelling-shrinking properties at minimum cracking, strength loss and enhanced compressibility expenses.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.7
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• pp.1205-1210
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• 2007

Several mechanisms are introduced for the procurement of capacity adequacy. In the competitive electricity market, however, it is a GENCO that makes generation investment decision. A GENCO will invest a new generator when it can get more profit than cost. There requires a model to evaluate profit with respect to a new generation investment. In the view of long-term investment, evaluation of a profit of a generator in the electricity market is quite different from that of short-term operation. In this paper, a new profit-evaluation model is proposed for the long-term generation investment. It can treat the probabilistic characteristics of generators, ie, forced-outage-rates, which affect profit of generators.

• Journal of the Korea Institute of Building Construction
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• v.13 no.6
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• pp.549-556
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• 2013

This study analyzed the actual use of defect deposits for financing long-term expenses (that is, expenses incurred within 4-10 years of building completion) and for financing short-term expenses (that is, expenses incurred within 3 years of building completion). Therefore, 36 cost data on the expenses financed out of defect deposits for apartment complexes were collected from construction companies and analyzed using statistical methods. The findings revealed that 62.6 percent of defect deposits were spent to resolve actual defects, and 37.4 percent were spent resolving resident complaints. Furthermore, these results are valid regardless of the location of the complexes. As such, these results could be of significance when establishing or revising regulations regarding the repair of the long-term defects of apartment complexes.

• Journal of Internet of Things and Convergence
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• v.6 no.4
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• pp.7-14
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• 2020

This study analyzed the effect of the number of deaths of circulatory system diseases according to 12-day short-term exposure of carbon monoxide from January 2010 to December 2018, and predicted the future treatment cost of circulatory system diseases according to increased carbon monoxide concentration. Data were extracted from Air Korea of Korea Environment Corporation and Korea Statistical Office, and analyzed using Poisson regression analysis and ARIMA intervention model. For statistical processing, SPSS Ver. 21.0 program was used. The results of the study are as follows. First, as a result of analyzing the relationship between the impact of short-term carbon monoxide exposure on death of circulatory system diseases from the day to the previous 11 days, it was found that the previous 11 days had the highest impact. Second, with the increase in carbon monoxide concentration, the future circulatory system disease treatment cost was estimated at 10,123 billion won in 2019, higher than the observed value of 9,443 billion won at the end of December 2018. In addition, when summarized by month, it can be seen that the cost of treatment for circulatory diseases increases from January to December, reflecting seasonal fluctuations. Through such research, the future for a healthy life for all citizens can be realized by distributing various devices and equipment utilizing IoT to preemptively respond to the increase in air pollutants such as carbon monoxide.

• Korea Journal of Hospital Management
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• v.4 no.1
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• pp.1-20
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• 1999

Since the late 1980s, there have been radical changes in the managerial environment of Y University Medical Center(YUMC). Externally, the competition among hospitals has intensified due to the establishment of universal health insurance in 1939 and the entrance of large enterprises into the health care industry in the early 1990s. In addition, government regulation of medical institution is becoming stricter. Also, consumer groups have continued to demand the respect for patient rights and improvement of the quality of medical services. Internally, the financial condition of YUMC has worsened, not only because weak control and poor mediation in its large-scale structure have made its operation inefficient, but also because the rates of increase in the prices of goods and labor have grown faster than any increases in revenues. This study on materials management at YUMC presents a way for YUMC to reduce costs and increase its productivity, thereby overcoming its financial difficulties and dealing with external pressures. This study utilized the case studies of the materials purchasing and medical supply management in the United States and the comparative analysis of management to suggest short-term and long-term alternatives for innovation in YUMC. The goals of the short-term alternatives for innovation are to centralize the purchasing and supply departments and to simplify the decision-making processes. Through these attempts, it is estimated that YUMC's costs could be reduced by $600,000 per year. In the long-term, it is necessary to consider introducing a Supply Processing Distribution(SPD) system and setting up a centralized electronic system for supply and inventory management, although it is difficult to estimate the effect of cost-cutting because of the lack of analysis data. Thus, YUMC should thoroughly analyze initial investment costs and economical efficiency generated from long-term alternatives.

• Food Science of Animal Resources
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• v.32 no.4
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• pp.414-427
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• 2012

Carcass characteristics and meat quality traits as a function of endpoint months of slaughter age (26 vs 32 mon) and chiller ageing (1 vs 10 d) were evaluated for m. longissmus of 26 Hanwoo steers fed with commercial diets including whole crop barley silage. Totally twenty six Hanwoo steers for 6 mon of age that were fed until 26 mon of age constituted the short term-fed group and fed until 32 mon of age constituted long-term fed group. Carcasses were chilled for 24 h and were graded. Strip loin samples were divided into two age groups (1 d and 10 d). Long-term feeding increased carcass weight, rib-eye area, yield grade, marbling score, firmness and quality grade of the meat. The feeding for 32 mon produced tender, juicy meat (p<0.01) with lower cooking loss and higher rating score (p<0.05) than short term feeding, while other quality traits were not influenced by the length of feeding. Intramuscular fat content and oxidative stability (TBARS value) were significantly (p<0.05) higher in beef from long-term feeding however the length of feeding did not alter the fatty acid composition. Chiller aging reduced instrumental tenderness (WBSF value), improved color, sensory tenderness, acceptability and rating of beef. The results of the present study mirrors that Hanwoo steers until 32 mon of age overall improved carcass traits and palatability compared to that for 26 mon. However, from the viewpoints of economical and environmental aspects, cost of the additional feeding for 6 mon for value-adding of eating quality was relatively high and the effects in turn were limited.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.51-62
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• 2017

For the asset management of a water pipe network, it would be necessary to understand the extent of the maintenance cost required for the water pipe network for the future. This study would develop a method to draw the optimum cost required for the maintenance of the water pipe network in waterworks facilities to maintain the aim revenue water ratio and to achieve the target revenue water ratio, considering the water service providers' waterworks condition and revenue water ratio comprehensively. This study conducted a survey with 96 water service providers as of the early 2015 and developed models to estimate the optimum maintenance cost of the water pipe network, considering the characteristics of the water service providers. Since the correlation coefficient of all the developed models was higher than 0.95, it turned out that it had significant reliability, which was statistically significant. As a result of applying the developed models to the actual water service providers, it was drawn that increasing revenue water ratio to more than a certain level can reduce the maintenance cost of the water pipe network by a great deal. In other words, it is judged that it would be the most efficient to secure the reliability of waterworks management by increasing the short-term revenue water ratio to more than a certain level and gradually increase the revenue water ratio from the long-term perspective. It is expected that the proposed methodology proposed in this study and the results of the study will be used as a basic research for planning the maintenance of water pipe network or establishing a plan for waterworks facilities asset management.