• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.9
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• pp.513-518
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• 2009

The building HVAC systems generally have very different qualities of performance and durability with the superintendent's interest in or capability of management and maintenance of them. The poor management of these systems finally lead to the shortening of the life expectancy and result in the increase of operating cost and energy consumption due to their low efficiencies. So it is necessary to develop tools to maintain adequately and to operate efficiently various building service equipments in order to cope with actively the global environment problems and energy crises. In this study the LCC based calculation program and package were developed, which could be used for analyses of the economic performance and determination of the reasonable maintenance time and methods of building HVAC systems.

• Resources Recycling
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• v.33 no.2
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• pp.16-23
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• 2024

The electrolysis for extracting magnesium from seawater or brine primarily involves recovery of magnesium via precipitation as the form of magnesium hydroxide. The technology is classified into cation-exchange membranes (CEM), anion-exchange (AEM) membranes, electrodialysis, and membraneless methods. Recent research has focused on enhancing the efficiency and selectivity of magnesium recovery from seawater or brine containing magnesium, with expectations of effective magnesium recovery even with normal seawater. In a future, the optimization of the selective and efficient recovery of magnesium and various valuable substances through long-term operation of scaled-up systems is crucial with enhancing economic and environmental viability. It is essential to realistically estimate operational costs considering the membrane's lifespan and replacement cycle. Also, detailed and practical process models should be developed based on monitoring data on various factors.

• Korean Journal of Construction Engineering and Management
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• v.7 no.6
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• pp.165-174
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• 2006

Recently, the architecture remodeling is rising as new alternative for activating the construction market as the interest toward life cycle of buildings has increased. But the reality is that current remodeling business is suffering various types of difficulties in its performance due to the absence of general management technology and factor technology in systematic performance procedure or evaluation, etc toward remodeling effect, evaluation on performance, imperfect system for reflecting user requirements and remodeling life cycle ; planning, $feasibility ^{\circ}\hat{E}designing^{\circ}\hat{E}construction^{\circ}\hat{E}management$ along with lack of overall understanding on remodeling. Accordingly, this research has attempted to search for an effective management method through overall understanding in project performance by presenting work procedure of remodeling project and analysis items for decision making, etc centered on early planning stage out of three stages called planning, designing and construction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.274-283
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• 2016

The study of maintenance planning is important in military weapon systems because it can improve their availability and reduce the operational and maintenance cost during the total life cycle. In maintenance planning, it is important to determine the preventive maintenance task and its optimal interval. This paper focuses on the hard time task, which is one of the preventive maintenance tasks. A hard time task removes an item or restorative action before some specified maximum age limit to prevent functional failure. The Monte-Carlo simulation model was proposed to help understand the cost effectiveness of a hard time task. In the simulation, various shape parameters of the Weibull distribution and cost ratio of corrective maintenance to preventive maintenance were assumed. Using a Monte-Carlo simulation, a quantified cost saving effect and optimal preventive maintenance interval were suggested.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.77-86
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• 2016

Before urban railway vehicles reach their design life-span, operating agencies should determine when to buy new vehicles. Previous LCC (Life Cycle Cost) studies were limited because they independently focused on existing vehicles based on costs that directly impacted only the operating agency without considering effects such as social costs and the reduction of maintenance costs. Thus, it is difficult to systematically determine when to buy new vehicles. This study investigated the operating and maintenance related costs, especially from additional expenses and social costs due to unexpected vehicle failures and safety accidents, and did an economic analysis of scenarios with different discount rates. Considering that the public is very concerned about safety after the Sewol ferry accident, additional costs, which include social costs, should be included in the analysis. This study shows that the economic priority of scenarios may change depending on whether those costs are included and on the discount rate. The results of this study can help in the decision-making process for the planning and buying of new trains.

• Journal of Embryo Transfer
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• v.20 no.3
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• pp.311-315
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• 2005

This study was conducted to investigate the effects of disregarding of heat detection on embryo production in superovulation of Hanwoo cows. Donors which showed 1 or 2 times of normal heat and had no abnormality of reproductive tract were selected The superovulation was performed injection of 2.5 mL FSH (Antorin R-10, Japan) 2 times on 5 days before next heat and continuously with the reduction of dose to 0.5 mL of first injection 2 times in a day for next 3 days. Otherwise, the donors of CIDR group were inserted CIDR plus (with the capsule of estradiol benzoate 10 mg) on Day 10 from standing heat for 9 days. On 6 days from insertion of CIDR, FSH was injected above same manners. The response according to the natural heat and CIDR were $82.2\%,\;89.7\%$, respectively. There were no difference between both treatments. The recovery rates of embryos were 7.7, 10.5, respectively and transferable embryos were 3.4, 3.8. There showed significant difference between both treatments (p<0.05). These results suggested that disregarding of heat detection in superovulation could be produced transferable embryos for embryo transfer and preserve the donors from the excess hormonal administration and maintain the economical lift span of genetically available Hanwoo donors.

• The Journal of the Korea Contents Association
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• v.14 no.7
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• pp.529-540
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• 2014

Korea's baby boomers constitute a quarter of the population structure, and they are now faced with super-aged era represented by the life expectancy of 100 years. Since this generation who played a leading role in economic growth of the country has needs for active participation in society and continuous economic activities based on the healthy bodies, sufficient wealth and desires for cultural consumption, it is called 'active seniors' as a new demographic class differentiated from the conventional elder generation. This study was intended to investigate housing needs of baby boomers as preliminary seniors in Seoul with the highest residential density of the baby boomers through a bottom-up process from the perspective of consumers, and to select the findings as criteria for residential complex plans. The analysis results showed that 'social accessibility' was most highly valued among baby boomers in Seoul, and 'medical accessibility' was determined to be the second most important factor. Other items such as 'convenience of living' and 'spatial cognition' were ranked as the least important factors. These findings suggest that the life style of baby boomers in Seoul is very similar to that pursued by active seniors in terms of life cycle, and it is determined to be a characteristic as a niche for housing needs different from the one found in conventional elder generation.

• Informatization Policy
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• v.20 no.4
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• pp.71-88
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• 2013

Probability of technology risk is expected to increase as the post catch-up innovation, characterized by high uncertainty and high risk, would dominate in the coming era of post catchup. Social controversy on online game as a post catch-up innovation is still ongoing, though the shutdown law was enacted by the government. Socio-technical vulnerability causing technology risk paradoxically arose from the world top-level ICT infrastructures and has been reinforced by developmentalism. While both the pros and cons of the regulation fail to recognize dilemma objectively, social cost is brought about and accumulated. With recognizing dilemma between technology innovation and risks, we can tackle technology risks and ensure responsible innovation in post catch-up era.

• Journal of Technology Innovation
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• v.28 no.1
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• pp.31-52
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• 2020

This study was started to verify the preliminary(Ex-ante) discrimination power of the firm's high-activity using the 'Forward-looking' oriented technology appraisal model used in technology financing. The analytical firms are classified into the industry (manufacturing / non-manufacturing) and the age of company (initial / non-initial). High-activity SMEs are defined as those that achieve at least twice the average asset turnover ratio of the cluster. As a result of the discriminant model by applying C5.0 method, which is one of decision tree models, classification accuracy is more than 99% in all industries and the age of company, and it is confirmed that the discriminant power of the model is stable. As a result, the management expertise, capital involvement and funding capacity items were identified as a critical variable for the high-activity SMEs. In addition, the technology management capability and technology life cycle were also confirmed to be the items to determine high-activity SMEs in the manufacturing industry. Through this, it was possible to confirm some possibility of prior discrimination and policy utilization of high-activity SMEs by using technology appraisal items.

• Convergence Security Journal
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• v.23 no.1
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• pp.109-115
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• 2023

The future outlook for defense faces various and challenging environments such as the acceleration of uncertainty in the global security landscape and limitations in domestic social and economic conditions. In response, the Ministry of National Defense seeks to address the problems and threats through defense innovation based on scientific and technological advancements such as artificial intelligence, drones, and robots. To introduce advanced AI-based technology, it is essential to integrate and utilize data on IT environments such as cloud and 5G. However, existing traditional security policies face difficulties in data sharing and utilization due to mainly system-oriented security policies and uniform security measures. This study proposes a paradigm shift to a data value-based security policy based on theoretical background on data valuation and life-cycle management. Through this, it is expected to facilitate the implementation of scientific and technological innovations for national defense based on data-based task activation and new technology introduction.