• Journal of Ceramic Processing Research
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• v.19 no.5
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• pp.378-382
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• 2018

It is a known fact that the cement production is responsible for almost 5% of total worldwide $CO_2$ emission, the primary factor affecting global warming. Geopolymers are valuable as ordinary Portland cement (OPC) substitutes because geopolymers release 80% less $CO_2$ than OPC and have mechanical properties sufficiently similar to those of OPC. Therefore, geopolymers have proven attractive to eco-friendly construction industries. Geopolymers can be fabricated from aluminum silicate materials with alkali activators such as fly ash, blast furnace slag, and so on. Integrated gasification combined cycle (IGCC) slag has been used for fabricating geopolymers. In general, IGCC slag geopolymers are fabricated with finely ground and sieved (<128 mesh) IGCC slag. The grinding process of as-received IGCC slag is one of the main costs in geopolymer production. Therefore, the idea of using as-received IGCC slag (before grinding the IGCC slag) as aggregates in the geopolymer matrix was introduced to reduce production cost as well as to enhance compressive strength. As-received IGCC slag (0, 10, 20, 30, 40 wt%) was added in the geopolymer mixing process and the mixtures were compared. The compressive strength of geopolymers with an addition of 10 wt% as-received IGCC slag increased by 19.84% compared to that with no additional as-received IGCC slag and reached up to 41.20 MPa. The enhancement of compressive strength is caused by as-received IGCC slag acting as aggregates in the geopolymer matrix like aggregates in concrete. The density of geopolymers slightly increased to $2.1-2.2g/cm^3$ with increasing slag addition. Therefore, it is concluded that a small addition of as-received IGCC slag into the geopolymer can increase compressive strength and decrease the total cost of the product. Moreover, the direct use of as-received IGCC slag may contribute to environment protection by reducing process time and $CO_2$ emission.

• Architectural research
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• v.24 no.3
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• pp.85-91
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• 2022

The public rental housing policy aims to provide the housing to the vulnerable class who do not have enough credit to own houses. The Korean government introduced new policies for housing supply to improve the availability of new houses. However, it is difficult to expand the supply because of the accumulated deficit of public rental housing. In this study, the economic feasibility of long-term public rental housing reconstruction projects was examined to ensure the economic and sustainable growth of public rental housing. The research found that the compensation for the accumulated deficit is needed. Also the research analyzed and identified the factors affecting the economic feasibility of reconstruction projects. The significant factors identified in this research are: the supply price of pre-sale/rental housing in the reconstruction project, total cost of the reconstruction project, and total floor area of the reconstruction project. According to the analysis results, it is necessary to increase the rent of existing long-term public rental housing, expand the government subsidy, increase the supply price of pre-sale/rental housing, and reduce the total project cost. However, there are limitations. For example, the fluctuations of construction market, residents' burden of housing costs, and the limit of the budget of the public housing authority. The increasing total Floor Area Ratio(FAR) limitation of the reconstruction project would be the realistic solution to the problem because it gives incentives to the reconstruction project.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.4
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• pp.33-40
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• 2022

Sharehouse has been supplied as an alternative to solving the steadily increasing one-room housing problem of single-person households every year, and it is necessary to investigate the satisfaction of residents who actually live in sharehouse through P.O.E. Therefore, this study analyzed priror researches related to the existing one-person households, sharehouses, and satisfaction surveys, and summarized indicators with high relevance and frequency to derive satisfaction survey factors that can clearly evaluate the improvement architectural plan of sharehouses. As a result, it was classified into 4 items in the 'general information' category to investigate the status, housing rental type, and housing cost of the sharehouse, 15 factors in the 'peripheral environment' category to evaluate the safety, 3 factors in the 'community' category, and 17 factors in the space (facility) and service category. In the "General Information" section, the overall one-person housing satisfaction, desired sharehouse type, housing rental type, housing cost, and living expenses were reduced. In the "Surrounding Environment", accessibility to public office, accessibility to cultural facilities, accessibility to medical facilities, accessibility to work and school, convenience stores, noise pollution and safety. In addition, in the "community" section, it consists of interactions with various people, relationships with housemates and in the "space (facilities) and service" section, heating, waterproof, soundproof, ventilation, moisture and condensation blocking, facility management, interior, room size, built-in furniture, storage space, laundry, parking. Most of the scales for each factor were 5-point Likert scales, allowing evaluation of the degree of satisfaction, and some factors presented criteria to induce structured answers. Therfore, it is expected that the survey will be conducted on residents who actually live by deriving factors for the satisfaction survey of one-person households living in the sharehouse, and the current status of the sharehouse will be identified, and the degree of satisfaction will be analyzed to be used for research.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.14-15
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• 2020

The need for off-site construction has increased in the construction industry in Korea in recent years due to the enforcement of the 52-hour workweek, the increasing age of workers on construction sites, the deepening dependence on overseas workers, and the stagnation of productivity in the construction industry. Thus, studies on OSC started in April 2020. In addition, as a national policy study advocating the modular construction method, which is one of the OSC methods, was completed in the first half of 2019. 70 housing units in two complexes that satisfied the Housing Act requirements have been supplied to citizens. However, although modular construction methods have been recognized as a dramatic construction method that achieves shortened construction schedules and solves the issues of cost reduction and the shortage of technical workers on sites by combining the advantages of the manufacturing industry and applying the economies of scale, realistically it has issues due to the rising cost of steel and a low pre-fabrication ratio. Moreover, the construction time of core parts, such as those built by pouring concrete, has become a factor that hinders the shortening of construction times. Thus, this study aims to propose a precast concrete(PC) modular construction system, which fuses three-dimensional infill as an interior finish material and a three-surface PC module that can acts as a structure for a construction method that is economical and can shorten construction time.

• Asian Journal of Innovation and Policy
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• v.8 no.3
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• pp.396-416
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• 2019

The key conditions for the promotion of innovative technology-based start-ups are expanding the market for innovative technology products and services, increasing equity-based funding opportunities, promoting the commercialization of technological innovation, and establishing a fair-trade system for start-ups to compete fairly in the market. Besides, there is a need for a support system that minimizes the cost of failure in case of business failure to facilitate re-challenge and provides education and training opportunities to enhance entrepreneurial capabilities. To activate technology-based start-ups, the Korean government introduced the TIPS policy in 2013. It is a program that creates technology start-up with private investment led by successful venture entrepreneurs, which has shown remarkable achievement and is regarded as the most successful policy in this field up to now. The most critical factor contributed to the success of this program is to invite private investors to select a technology entrepreneurship team and provide mentoring with the investment. The government provides R&D funding with matching investment, commercialization and marketing support to ensure that technology start-ups survive crossing the death-valley. Subsequent investments from domestic and abroad investors are actively made and it is becoming a representative technology-based start-up program in Korea.

• Journal of Adhesion and Interface
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• v.7 no.4
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• pp.60-64
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• 2006

In modern vehicle construction the search for means of weight reduction, improving durability, increasing comfort and raising body stiffness are issues of priority to the design engineer. The intelligent usage of many materials such as high strength steel, light-alloys and plastics enables a significant vehicle weight reduction to be achieved. The classical joining techniques used in the automobile industry need to be newly-evaluated since they often do not present workable solutions for such mixed-material connections, for example aluminium/steel. Calculation/simulation methods have made progress as a key factor for broader and more cost-effective implementation of structural bonding. This will lead to reduction of spotwelds and accelerate the car development. A special focus of the paper is the use of high strength steel grades. It will be shown that adhesive bonding is a key tool for yielding the potential of advanced high strength steel for low gauging without compromising the stiffness. The latest status of adhesive development has been described. Improvements with physical strength and glass temperature as well as of process relevant properties are shown. Also the situation regarding occupational hygiene is treated, showing that by further spotweld point reduction the emission around the working area can be even lowered against the current praxis. High performing lightweight design cannot longer do without high performing crash durable adhesives.

• Journal of the Korean Ceramic Society
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• v.54 no.4
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• pp.272-277
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• 2017

Organic-inorganic hybrid thermoelectric materials have obtained increasing attention because it opens the possibility of enhancing thermoelectric performance by utilizing the low thermal conductivity of organic thermoelectric materials and the high Seebeck coefficient of inorganic thermoelectric materials. Moreover, the organic-inorganic hybrid thermoelectric materials possess numerous advantages, including functional aspects such as flexibility or transparency, low cost raw materials, and simplified fabrication processes, thus, allowing for a wide range of potential applications. In this study, the types and synthesis methods of organic-inorganic thermoelectric hybrid materials were discussed along with the methods used to enhance their thermoelectric properties. As a key factor to maximize the thermoelectric performances of hybrid thermoelectric materials, the nanoengineering to control the nanostructure of the inorganic materials as well as the modification of the organic material structure and doping level are considered, respectively. Meanwhile, the interface between the inorganic and organic phase is also important to develop the hybrid thermoelectric module with excellent reliability and high thermoelectric efficiency in addition to its performance in various electronic devices.

• Journal of Preventive Medicine and Public Health
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• v.48 no.4
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• pp.180-187
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• 2015

Objectives: Metabolic syndrome is an important etiologic factor in the development of certain types of cancers. The economic cost of the treatment of cancer has been steadily increasing. We therefore estimated the economic burden of cancers attributable to metabolic syndrome in Korea. Methods: We reviewed metabolic syndrome-related cancers and relative risk and then calculated population attributable fractions. We analyzed insurance claims data for metabolic syndrome-related cancers in 2012 in order to estimate the direct costs associated with these cancers, including hospitalization, outpatient visits, transportation costs, and caregivers' costs as well as indirect costs such as loss of productivity due to cancer treatment and premature death. Results: In 2012, 18 070 patients in Korea had cancers attributable to metabolic syndrome. The economic burden was USD 199.8 million and the direct and indirect costs were USD 124.5 million and USD 75.3 million, respectively. Conclusions: We estimated the economic burden of cancers attributable to metabolic syndrome in Korea and the efforts are necessary to reduce this burden.

• Journal of the Korea Institute of Building Construction
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• v.2 no.1
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• pp.147-154
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• 2002

In the Past, The selection of individual method of construction was done by head of construction site or an experienced person very frequently. By doing this, The wrong selection of construction method without exact adjudication of construction site situation lead to increasing of cost and extension of construction term. Finally it will effect all over the construction process. Especially, In case of underground construction in the beginning, there are a lot of a variable factor and it also effect on the entire construction process and it need very careful process. The purpose of this study is to present the best suitable methodology for selection of construction method by considering potential risk of construction method and variables together with external condition for underground construction. The purpose of this study Is to select the most suitable construction method by analysing potential conditions(construction site situation and client request in designing ) To do this, We prepared arrangement rule to arrange the conditions for construction method. And thin make checklist of the analyzing construction method. Though above process, To expect the risk of individual construction method using above risk checklist and using Analytic Hierarchy process among Multiple-Criteria Decision making, the professional opinions is to be adapted. By doing this, it can lead and select the most suitable construction method considering the data which get from risk density test.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.41-52
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• 2020

This paper investigates the stress-reducing preventive maintenance model through numerical experiments. The preventive maintenance model is used to analyze the relationship between related conditions and variables to gain insight into the efficient operation of the system when performing preventive maintenance in real-world situations. Various preventive maintenance models have been developed over the past decades and their complexity has increased in recent years. Increasing complexity is essential to reflect reality, but recent models can only be interpreted through numerical experiments. The stress-reducing preventive maintenance is a newly introduced preventive maintenance concept and can only be interpreted numerically due to its complexity, and has received little attention because the concept is unfamiliar. Therefore, for information purposes, this paper investigates the characteristics of the stress-reducing preventive maintenance and the relationship between parameters and variables through numerical experiments. In particular, this paper is focusing on the economic feasibility of stress-reducing preventive maintenance by observing changes in the optimal preventive maintenance period in response to changes in environmental stress and the improvement factor. As a result, when either the environmental stress or the improve effect of stress-reducing preventive maintenance is low, it is not necessary to carry out the stress-reducing preventive maintenance at excessive cost. In addition, it was found that the age reduction model is more economical than the failure rate reduction model.