• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.3
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• pp.268-276
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• 2015

In this study, $CO_2$ reduction type quaternary component high fluidity concrete was produced with more than 80% reduction in cement quantity to increase the use of industrial byproducts and enhance construction performance, thereby reducing $CO_2$ emissions. Furthermore, the quality properties, and $CO_2$ reduction performance of this concrete were evaluated. As a result of the quality evaluation of quaternary component blended high fluidity concrete with $CO_2$ reduction, the target performance could be achieved with a 80% or more reduction of cement quantity by mixing a large amount of industrial byproducts. The required performance level was obtained even though the flow, dynamic, and durability characteristics decreased a little compared to conventional mix. In addition, to analyze the $CO_2$ reduction performance of quaternary component blended high fluidity concrete with $CO_2$ reduction, the life cycle assessment (LCA) of the concrete was performed and the results showed that compared to the conventional mix, the carbon emissions decreased by 62.2% and the manufacturing cost by 24.5%.

• Journal of the Korea Institute of Building Construction
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• v.18 no.4
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• pp.347-354
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• 2018

This paper verifies the superiority of warming work in winter by applying the insulation gang-form to the apartment housing site and analyzes the economic feasibility of the application. According to the experimental results, the actual cost of warming work was about 52 million won less than planned, and 160 million won less than the existing average.(Note - The cost of gang form material increased from 260 million won to 310 million won after the change) As a result, the construction cost could be reduced by about 110 million won. As the costs of warming work can change depending on the number of floors, the building number, and the area of each site, it is deemed necessary to conduct a thorough review in advance at the site where the cost of warming work is to be applied.

• Journal of the Korea Institute of Building Construction
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• v.4 no.2
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• pp.129-136
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• 2004

High fluidity concrete(HFC) requires high dosage of superplasticizer to acquire sufficient fluidity, and high contents of fine powder and viscosity enhancing admixtures to resist segregation. The use of high amount of admixtures to make HFC at batcher plant in ready mixed concrete company is one of the reasons to raise the manufacturing cost of HFC. For this reason, new type of manufacturing method of HFC are described using both flowing concrete method and segregation reducing superplasticizer(SRS) in order to gain economical profit and offer the convenience for quality control.. As dosage of melamine based superplasticizer increases, it shows that fluidity and bleeding increase, while air contents and ratio of segregation resistance decrease. It also shows that addition of viscosity agent into superplasticizer reduce bleeding and improve segregation resistance of concrete. Dosage of AE agent into superplasticizer containing viscosity agent recovers loss of air contents during flowing procedure. Combination of proper contents of superplasticizer, viscosity agent and AE agent make possible to develope segregation reducing type superplasticizer. Compressive strength of high fluidity concrete applying flowing method with it is higher than that of base concrete. No differences of compressive strength between compacting methods are found. For the estimation of construction cost of high fluidity concreting using segregation reducing type superplasicizer, under same strength levels, although material cost of high fluidity concrete is somewhat higher than that of plain concrete due to segregation reducing type superplasticizer cost, labor cost and equipment cost of high fluidity concrete is cheaper than that of plain concrete. However, based on the strength differences, high fluidity concrete shows lower material cost, labor cost and equipment cost than that of plain concrete due to decreasing in size of member and re-bar caused by high strength development of concrete.

• Journal of Digital Convergence
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• v.17 no.5
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• pp.217-223
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• 2019

A study in predicting defects of spot welding in real time in automotive field is essential for cost reduction and high quality production. Welding quality is determined by shear strength and the size of the nugget, and results depend on different independent variables. In order to develop the real-time prediction system, multiple regression analyses were conducted and the two dependent variables were obtained with sufficient statistical results with three independent variables, however, the quality prediction by the regression formula could not ensure accuracy. In this study, a multi-layer neural network circuit was constructed. The neural network by 10 dynamic resistance variables was constructed with three hidden layers to obtain execution functions and weighting matrix. In this case, the neural network was established with three independent variables based on regression analysis, as there could be difficulties in real-time control due to too many input variables. As a result, all test data were divided into poor, partial, and modalities. Therefore, a real-time welding quality determination system by three independent variables obtained by multiple regression analysis was completed.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.171-177
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• 2021

The Southeastern economic zone was centered on small and medium-sized manufacturing, but industrial changes and corona 19 caused the local economic downturn. This study presented the difficulties of companies related to the aviation specialization industry and suggested ways to revitalize the local economy in order to revitalize the local economy in the southeast region. First, aeronautical specialized parts companies need various support to improve the structural problems of passive industries. Second, the industry needs a systematic education system that develops products and technologies that meet international standards and conducts international certification education to support stable supply and demand of human resources by cultivating professional manpower for systematic project performance. Third, the industry needs financial and administrative support from the government to develop technologies and products that meet high standardization standards. In addition, it is necessary to provide support to systematically improve the limitations and difficulties of companies, such as finding and expanding customers of small and medium-sized companies and supporting investment for cost reduction.

• Health Policy and Management
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• v.14 no.1
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• pp.89-120
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• 2004

The purpose of this empirical study is to test hypotheses in order to identify the cost drivers that drive indirect costs in general hospitals in Korea. In various cases' studies, it has been suggested that overhead costs are driven by volume and complexity variables, how they are structurally related and how the cost impacts of these variables can be A unique feature of the research is the treatment of complexity as an endogenous variable. It is hypothesized that level of hospital complexity in terms of the number of services provided(i.e., “breath" complexity) and the intensity of individual estimated in practice. overhead services(ie., “depth" complexity) are simultaneous determined with the level of costs needed to support the complexity. Data used in this study were obtained from the Database of Korean Health Industry Development Institute, Health Insurance Review Agency and analyzed using simultaneous equation model, path model. The results found those volume and complexity variables are all statistically signi-ficance drivers of general hospital overhead costs. This study has documented that the level of service complexity is a significant determinant of hospital overhead costs, caution should be exercised in interpreting this as supportive of the cost accounting procedures associated with ABC. with ABC.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.12
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• pp.2216-2225
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• 1992

In recent years, machining turns to flexible manufacturing. Industry in machining requires to increase machining productivity and to reduce costs. To adapt this trend it is necessary to optimize machining condition. Even though many researches in this are introduced various way to set the optimal condition, still there are not enough. Therefore this research was done to select the optimal cutting condition for industry, and to develope the computer program to select the optimal cutting condition automatically. Also, this program was applied to many companies, and compare costs per minute. The results of this research will contribute to increase machining productivity of various companies with the automatic selection of optimal cutting condition.

• Composites Research
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• v.35 no.4
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• pp.223-231
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• 2022

With the rapid growth of the future mobility market, a large number of electronic parts are being used in automobile, and the importance of electromagnetic interference (EMI) shielding in the automobile market is growing to minimize malfunctioning among the parts. Accordingly, conductive polymer composites (CPCs) are getting a lot of attention as EMI shielding materials for the automotive, but there are still challenges in CPCs like high content of conductive filler to achieve proper EMI shielding effectiveness, and poor mechanical properties. This paper introduces main methods to manufacture CPCs with segregated filler structure, which can significantly reduce the filler content, and analyzes EMI shielding performance of each manufacturing method.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.34-46
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• 2021

In the domestic data exchanging market, unreasonable pricing of purchase data is consistently mentioned as a major obstacle in data trading. This is a problem caused by the inability to properly evaluate the value of data products due to lack of product information and experience in using them. In order to activate trading, the data exchanges need to provide information that allows consumers to comprehensively judge the value of data products in addition to prices. The cost-based, income-based, and market-based methods, which are mainly applied to data valuation, are insufficient as data valuation methods to stimulate trading and distribution because only price information, a result of valuation from a supplier's point of view, can be shared with consumers. This study aims to develop a measurable valuation method that allows data trading stakeholders (exchanges, suppliers, and consumers) to judge and share the value of data products from a common perspective. To this end, we identified the value drivers of data products, which are considered important in overseas data exchanges and related research, and derived an evaluation method that can quantitatively measure each value driver. In addition, evaluation criteria in the form of a rating table were developed using data products for transactions, and a value evaluation index was developed through stratification analysis (AHP) to enable relative value comparison. As a result of applying the evaluation criteria to actual data products, it was found that the evaluation values were differentiated according to the characteristics of individual data products, so it could be used as a relative value comparison tool.

• Elastomers and Composites
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• v.14 no.3
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• pp.161-168
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• 1979

이 논문(論文)의 목적(目的)은 열적안정성(熱的安定性) 및 내노화성면(耐老化性面)에 있어서 디엔제3성분단위체(第三成分單位體)(diene termonomer)의 각각(各各)의 종류(種類)가 EPDM의 중합체(重合體)의 성질(性質)에 미치는 효과(效果)를 구명(究明)하는데 있다. 제3성분단위체(第三成分單位體) 5종(種)으로 각각(各各) 다음과 같다. 즉, ethylidene norbonene(ENB), butadiene(BD), dicyclopentadiene(DCPD), methyltetrahydroindene (MTHI) 및 1,4-hexadiene(HD)이다. 이들을 써서 만든 각각(各各)의 EPDM은 동(同)몰의 불포화도(不飽和度)로 만들어졌다. 또한 가황계(加黃系)는 동일(同一)한 황/촉진제계(黃/促進劑系)를 사용(使用)하였다. ENB-EPDM이 순(純)고무배합체(配合體) 및 충전제함유배합체(充塡劑含有配合體)의 가황(加黃)에 있어서 모두 함께 가장 빠른 가황속도(加黃速度)를 보였다. HD-EPDM은 순(純)고무배합체(配合體)에서 가황속도(加黃速度)가 가장느렸으나 충전제함유배합물(充塡劑含有配合物)에서는 DCPD-EPDM보다는 발랐다. BD-EPDM을 제외(除外)한 이들 중합체(重合禮)는 거의 같은 초기가교밀도(初期架橋密度)를 갖는다. 가교밀도(架橋密度) 및 가교형(架橋型)을 분석(分析)하여 보면 BD-EPDM 쇄(鎖)에서 부타디엔 단위(單位)는 블럭을 이루고 있다. 또한 HD-EPDM은 순(純)고무가황체(加黃體) 및 충전제배합가황체(充塡劑配合加黃體)에 있어서 원가교결합(原架橋結合)의 50%가 monosulfide의 구조(構造)를 가지고있다. 이외(外)의 4종(四種)의 EPDM 폴리머는 보다 낮은 monosulfide구조를 가진다. $177^{\circ}C(350^{\circ}F)$의 노화온도(老化溫度)에서 ENB 및 HD폴리머는 약(約) 65% monosulfide 가교(架橋) 및 거의 동일(同一)한 파괴에너지값$(E_b)$을 가진다. 그러나 1,4HD의 원가교(原架橋)의 monosulfide 구조함량(含量)이 보다 높다고 해서 그의 내노화성(耐老化性)이 다른 폴리머보다 더 좋다고는 생각되지 않는다. DCPD는 $177^{\circ}C(350^{\circ}F)$의 노화온도(老化溫度)에서 똑같은 monosulfide가교(架橋)를 가지나 노화온도(老化溫度)가 $259^{\circ}C(500^{\circ}F)$로 높아짐에 따라 monosulfide 함량(含量)도 증가(增加)한다. $550^{\circ}F(287.7^{\circ}C)$의 노화온도(老化溫度)에서는 EPDM폴리머의 모든 가교(架橋)가 monosulfide구조가 되나 전가교밀도(全架橋密度) 및 $E_b$ (신장률(伸長率), 절단시(切斷時)의)는 대단(大端)히 낮은 것으로 나타나는데 이것은 산화(酸化)에 의한 노화(劣化)에 기인(基因)되는 것으로 보인다. 질소기류(窒素氣流)속에서의 TGA의 분석결과(分析結果)를 보면 EPDM 가황체(加黃體)는 $800\sim935^{\circ}F(427\sim502^{\circ}C)$의 온도범위(溫度範圍)에서 분해(分解)되며 공기중(空氣中)에서는 $750\sim935^{\circ}F$ 범위(範圍)에서 분해(分解)한다.