• Journal of the Korean Society of Industry Convergence
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• v.26 no.2_2
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• pp.255-263
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• 2023

The shell and tube-type heat exchangers have been frequently used in many industrial field because of its simple structure and wide operation conditions and so on. The purpose of this study is to investigate the flow characteristics in single shell of shell and tube-type heat exchanger according to velocity and temperature of hot air released from heat exchanger simulator through numerical analysis. As the results, the temperature was decreased in almost quadratic curve from top to bottom in single shell of the shell and tube-type heat exchanger. Further the changes of pressure and velocity in outlet according to change of inlet temperature were not observed. The cost for operating the shell and tube-type heat exchanger should be compared the supply cost of hot air with that of velocity in order to make a economic decision.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.244-245
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• 2021

Design VE (Value Engineering) has been basic design and implementation design separately, but due to the recent change in guidelines, it is changing to implement only once in the implementation design stage. However, in the implementation design stage, construction costs, plans, and specifications based on the volume details are almost completed. Therefore, it is effective to perform the function analysis step after identifying information analysis and key issues through CostModeling based on functional center for the selected target in the process of implementing the VE performance procedure.

• Journal of Intelligence and Information Systems
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• v.14 no.1
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• pp.117-129
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• 2008

The cost-based scheduling work has been done in both the Operations Research (OR) and Artificial Intelligence (AI) literature. To deal with more realistic problems, AI-based heuristic scheduling approach with non-regular performance measures has been studied. However, there has been little research effort to develop a full inter-job cost propagation algorithm (CPA) for different jobs having multiple downstream and upstream activities. Without such a CPA, decision-making in scheduling heuristics relies upon local, incomplete cost information, resulting in poor schedule performance from the overall cost minimizing objective. For such a purpose, we need two types of CPAs : intra-job CPA and inter-job CPA. Whenever there is a change in cost information of an activity in a job in the process of scheduling, the intra-job CPA updates cost curves of other activities connected through temporal constraints within the same job. The inter-job CPA extends cost propagation into other jobs connected through precedence relationships. By utilizing the cost information provided by CPAs, we propose cost-based scheduling heuristics that attempt to minimize the total schedule cost. This paper develops inter-job CPAs that create and update cost curves of each activity in each search state, and propagate cost information throughout a whole network of temporal constraints. Also we propose various cost-based scheduling heuristics that attempt to minimize the total schedule cost by utilizing the cost propagation algorithm.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.108-109
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• 2012

This talk will begin with the demonstration of facile synthesis of silicon nanostructures using the magnesiothermic reduction on silica nanostructures prepared via self-assembly, which will be followed by the characterization results of their performance for energy storage. This talk will also report the fabrication and characterization of highly porous, stretchable, and conductive polymer nanocomposites embedded with carbon nanotubes (CNTs) for application in flexible lithium-ion batteries. It will be presented that the porous CNT-embedded PDMS nanocomposites are capable of good electrochemical performance with mechanical flexibility, suggesting these nanocomposites could be outstanding anode candidates for use in flexible lithium-ion batteries. Directed self-assembly (DSA) of block copolymers (BCPs) can generate uniform and periodic patterns within guiding templates, and has been one of the promising nanofabrication methodologies for resolving the resolution limit of optical lithography. BCP self-assembly processing is scalable and of low cost, and is well-suited for integration with existing semiconductor manufacturing techniques. This talk will introduce recent research results (of my research group) on the self-assembly of Si-containing block copolymers for the achievement of sub-10 nm resolution, fast pattern generation, transfer-printing capability onto nonplanar substrates, and device applications for nonvolatile memories. An extraordinarily facile nanofabrication approach that enables sub-10 nm resolutions through the synergic combination of nanotransfer printing (nTP) and DSA of block copolymers is also introduced. This simple printing method can be applied on oxides, metals, polymers, and non-planar substrates without pretreatments. This talk will also report the direct formation of ordered memristor nanostructures on metal and graphene electrodes by the self-assembly of Si-containing BCPs. This approach offers a practical pathway to fabricate high-density resistive memory devices without using high-cost lithography and pattern-transfer processes. Finally, this talk will present a novel approach that can relieve the power consumption issue of phase-change memories by incorporating a thin $SiO_x$ layer formed by BCP self-assembly, which locally blocks the contact between a heater electrode and a phase-change material and reduces the phase-change volume. The writing current decreases by 5 times (corresponding to a power reduction of 1/20) as the occupying area fraction of $SiO_x$ nanostructures varies.

• Journal of Environmental Policy
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• v.9 no.2
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• pp.135-155
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• 2010

The purposes of the paper are to estimate welfare change from water quality degradation by using contingent valuation method in Namdae stream of Gangrung and identify what factors of Namdae stream are important to Gangrun citizens. The study results show their total WTP per year and per household, \117,040 to improve Namdae stream quality from grade 3 to grade 1, including monetary WTP \87,502 plus opportunity cost of volunteering time for protection campaign, \29,538. The amount of total welfare change from water quality degradation based on the total WTP estimated above is calculated to be \27 billion of which the amount, as a sort of damage cost from water quality degraded, is so huge. All projects and policies related to natural environments, therefore, should consider both indirect and direct effects from them because natural environments have the irreversibility once degraded or deteriorated and would ultimately be influential on humans, both current and future generations, with tremendous amounts of time and costs beyond our imagination.

• Journal of Climate Change Research
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• v.8 no.3
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• pp.265-273
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• 2017

Recently the Paris Climate Change Accord has been officially put into effect, making global efforts to implement Greenhouse Gas (GHG) reductions, and also International environmental regulations in the automotive sector will be further strengthened. The electric vehicle, which minimizes the particulate matter generated by existing internal combustion engine automobiles, is evaluated as a representative eco-friendly automobile. However, charging the battery of an electric vehicle is not fully environment-friendly if it is fueled by electricity that is being generated by fossil fuels as an energy source. The energy generated by the photovoltaic power generation system, which is an infinite clean energy, can be used to charge an electric vehicle's battery. Currently, shortage of charging facilities, time of charging, and high battery prices are the problem of activating the supply of electric vehicles. This study is to build a conjunction between the EVBSS (Electric Vehicle Battery Supply System) and ESS (Energy Storage System), which can quickly supply the photovoltaic charged battery to the required demand. If the charged battery in the Battery Swapping Station (BSS) is swapped swiftly, it will dramatically shorten the waiting time for charging the battery. As a result, if the battery is rented when it is needed, electric vehicles can be sold without the cost of a battery, which accounts for a large portion of the total cost, then the supply of electric vehicles are expected to expand. Furthermore, it will be an important alternative to maneuver climate change by minimizing GHG emissions from internal combustion engine vehicles.

• Journal of Information Technology Services
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• v.21 no.5
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• pp.51-64
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• 2022

Companies are planning and executing IT projects using information technology as a means to secure external competitiveness. However, IT projects have high risks and uncertainties due to the invisibility of outputs (systems, services, products), and changes in plans frequently occur during project execution. As a result, most IT projects are closed without achieving the target performance. This can lead to a waste of resources and money for the company, which in turn leads to the loss of opportunities to enter new markets. This study intends to analyze the effect of changes in the project plan on customer satisfaction, which is the project performance. Also, we want to find the importance of project planning so that the target performance of the IT project can be achieved. For the empirical analysis of this study, about 500 actual project data were collected. As for the analysis method, statistical analysis such as simple and multiple regression analysis and control effect was performed. Looking at the results of the analysis, it was found that the scope change affects the cost change and the schedule change. Also, changes in scope and cost were found to affect project performance. The theoretical performance of this study proved the theoretical fact that good project performance comes out if the IT project is executed as planned. The practical performance suggested the need for a change in project management by proving that thorough execution of the project planning stage can improve the project performance in the Korean project management culture, where the project planning stage is poorly performed for the rapid implementation of the IT project.

• The Journal of Fisheries Business Administration
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• v.54 no.2
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• pp.045-058
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• 2023

This study aims to analyze the cost of climate change damages to laver and sea mustard aquaculture, which are considered to be highly vulnerable to climate change in Korea. For this purpose, the correlation between aquaculture production and climate factors such as water temperature, salinity, air temperature, and precipitation was estimated using a panel regression model. The SSP scenario was applied to predict the changes in production and damage costs due to changes in future climate factors. As a result of the analysis, laver production is predicted to decrease by 18.0-27.2% in 2050 and 20.6-61.6% in 2100, and damage costs are predicted to increase from 29.7-50.8 billion KRW in 2050 to 35.7-116.1 billion KRW in 2100. Sea mustard production is projected to decrease by 24.5-37.2% in 2050 and 24.0-34.5% in 2100, with similar damage costs of 41.1-61.8 billion KRW and 41.1-58.6 billion KRW, respectively. These damage costs are expected to occur in the short term as damage caused by fishery disasters such as high temperatures, and in the long term as a decrease in production due to changes in aquaculture sites. Therefore, measures such as strengthening the forecasting system to prevent high-temperature damage, developing high-temperature-resistant varieties, and relocating fishing grounds in response to changes in aquaculture sites will be necessary.

• Journal of Acupuncture Research
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• v.33 no.2
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• pp.61-76
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• 2016

Objectives : This study was designed to clarify population-social characteristics that influence the utilization patterns of hospitalized patients in a traditional korean hospital, thereby providing clinical data which would help further improvements of traditional korean medical service in particular the Acupuncture and Moxibustion. Methods : We investigated population-social characteristics and annual utilization patterns of all patients who were hospitalized for more than 24 hours in a Korean Medical Hospital from January 2005 to December 2014. The obtained data were recorded in the EMR chart and statistical analysis was performed using SPSS 21.0. Additionally, data from the patients admitted to the department of Acupuncture and Moxibustion were analyzed separately. Results : 1. All inpatients had a significant annual difference in age, gender, hospitalized department, and disease code annually but not in re-hospitalization number. Inpatients of the department of Acupuncture and Moxibustion also varied in their age, gender, and disease code annually, but not in re-hospitalization number. 2. Pearson correlation analysis on all inpatients showed that the mean days of hospital treatments had a negative correlation with all variables except medical care insurance. Total cost, cost per day per person and recuperation cost had a positive correlation with all variables except medical care insurance. There was no meaningful relationship between nonrecuperation cost and the variables. 3. Stepwise multiple regression analysis on all inpatients showed that the mean days of hospital treatments had a negative correlation with all variables except automobile insurance. The total hospitalization costs had a positive correlation with both general insurance and medical care insurance. Cost per day per person and recuperation cost had a positive correlation with the females. There was no meaningful relationship between non-recuperation cost and the variables. 4. Pearson correlation analysis on inpatients of the department of Acupuncture and Moxibustion inpatients showed that the mean days of hospital treatments had a positive correlation with all variables except general insurance and automobile insurance. Total cost and recuperation cost had a positive correlation with all variables except medical care insurance, and cost per day per person had a positive correlation with females and general insurance. There was no meaningful relationship between non-recuperation cost and the variables. 5. Stepwise multiple regression analysis on inpatients of the department of Acupuncture and Moxibustion inpatients, the mean days of hospital treatments, total cost, cost per day per person and recuperation cost had a positive correlation with general insurance. There was no meaningful relationship between non-recuperation cost and the variables. Conclusion : Population-social characteristics of inpatients annually varies, and the change influences the utilization pattern.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.181-190
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• 2012

Cost of capital is one of the key factors of accounting regulation policy for telecommunication market. This paper aims at investigating efficient policy improvements concerning accounting regulation for telecommunication market focused on cost of capital calculation methods and its application. At First, cost of capital estimating method should be improved. In estimating the cost of equity capital, it is necessary to use benchmark method for Equity risk premium. It will reduce analytical errors caused by a rapid economic change and inflation. It is also more desirable to use debt premium adding method for the cost of debt capital. Optimal capital structure method may be considered a better way to estimates capital structure. Secondly, cost of capital estimating process also has to be reformed. Telecommunication industry changes rapidly so it does not reflect fast environmental changes. Therefore, cost of capital should be calculated every year. Cost of capital should be calculated by individual companies. There is information asymmetry between regulators and regulatees. Because of that cost of capital calculating process takes long time and cost a lot. To solve this problem, regulator should legislate on cost of capital calculation and then regulating companies report the calculating result. Lastly, major telecommunication companies are all listed now and it is possible to calculating it separately. We must continuously improve the estimating method and application of cost of capital and due to the fast growing of telecommunication industry. The process of determining the calculating method must be discussed and best method chosen.