• Title/Summary/Keyword: RCA

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A PARAMETER CHANGE TEST IN RCA(1) MODEL

  • Ha, Jeong-Cheol
    • 한국데이터정보과학회:학술대회논문집
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    • 2005.10a
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    • pp.135-138
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    • 2005
  • In this paper, we consider the problem of testing for parameter change in time series models based on a cusum of squares. Although the test procedure is well-established for the mean and variance in time series models, a general parameter case was not discussed in literatures. Therefore, here we develop the cusum of squares type test for parameter change in a more general framework. As an example, we consider the change of the parameters in an RCA(1) model. Simulation results are reported for illustration.

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Performance studies on concrete with recycled coarse aggregates

  • Yaragal, Subhash C.;Teja, Dumpati C.;Shaffi, Mohammed
    • Advances in concrete construction
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    • v.4 no.4
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    • pp.263-281
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    • 2016
  • Concrete continues to be the most consumed construction material in the world, only next to water. Due to rapid increase in construction activities, Construction and Demolition (C&D) waste constitutes a major portion of total solid waste production in the world. It is important to assess the amount of C&D waste being generated and analyse the practices needed to handle this waste from the point of waste utilization, management and disposal addressing the sustainability aspects. The depleting natural resources in the current scenario warrants research to examine viable alternative means, modes and methods for sustainable construction. This study reports processing Recycled Coarse Aggregates (RCA) using a rod mill, for the first time. Parameters such as amount of C&D waste for processing, nature of charge and duration of processing time have been optimized for obtaining good quality RCA. Performance of RCA based concrete and performance enhancement techniques of 50% RCA based concrete are discussed in this paper.

A Study on the Safety Improvement of Mixed Acid Storage Facility through the Accident Investigation Applicated by RCA (혼산 저장설비 사고의 근본원인 분석을 통한 안전성 향상방안)

  • Kwon, Nam-Ho;Kim, Dong-Joon
    • Korean Journal of Hazardous Materials
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    • v.6 no.2
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    • pp.47-54
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    • 2018
  • Mixed acid is very reactive and highly corrosive. it has been causing many accidents in a electronic industry, a steel industry, and a chemical industry. Therefore, it is required that the high safety level for the acid storage facilities. In this study, we investigated the accident causes for resent leak accidents with Root Cause Analysis (RCA). The root causes analysed by RCA were categorized as nine divisions by the their characteristics. Furthermore, each nine divisions causes was applied to the PDCA model which are using at OHSAS 18001. It is suggested that the nine division with the root causes can be the essential items for the development of the safety management manual. It is helpful to the safety improvement of the acid storage facility.

PERFORMANCE EVALUATION INDEX FOR COMPARING TRADITIONAL CONSTRUCTION METHODS WITH A ROBOT-BASED AUTOMATED CONSTRUCTION METHOD

  • Donguk Oh;Younghoon Lee;Ung-Kyun Lee;Nakju Lett Doh;Hunhee Cho;Kyung-In Kang
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.1088-1093
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    • 2009
  • To improve construction productivity and quality, and to make the construction environment safe, a new system, Robot-based Construction Automation (RCA), is currently being developed in Korea. To determine whether RCA is an improvement over traditional construction methods (TCMs), an evaluation method, called the Performance Evaluation Index (PEI), is suggested for RCA. The PEI considers the relationships among the factors influencing the performance of the system obtained using the Delphi method and the analytic hierarchy process (AHP). As the evaluation shows, RCA is much better than TCM except for three factors: the rate of work success, quality improvement by learning experience, and construction duration.

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RCA 프로젝트의 현상

  • 한국원자력산업회의
    • Nuclear industry
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    • no.1112 s.10
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    • pp.59-61
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    • 1982
  • 국제원자력기구(IAEA)의 아시아지역에서의 원자력과학기술협력협정(RCA)은 금년으로 10년을 맞이했다. 현재, 이 협정에 따라 동남아시아 여러 나라에서는 식품조사, 방사선계측기의 보수 등의 프로젝트와 UN개발계획 (UNDP)과의 협력에 의한 공업이용프로젝트가 활발하게 진행되고 있다.

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Effects of Radix Curcumae Aromaticae Extract in Rat Cardiac Endothelial Cells (울금 추출물이 배양 심장내피세포에 미치는 영향)

  • Kwon Kang Beom;Kim In Seob;Kim Hyun Gyu;Choi Ki Bang;Kim Yong Bok;Ryu Do Gon
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.17 no.1
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    • pp.71-76
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    • 2003
  • To test the protective effect of Radix Curcumae Aromaticae (RCA) on the damage of cardiac endothelial cells by xanthine oxidase (XO)/hypoxanthine (HX)-induced oxygen free radical, Neutral Red (NR), thiobarbituric acid reactive substances (TSARS), and DNA synthesis assay were used in the presence of RCA extract. The results of these experiments were obtained as follows ; Cardiac endothelial cells treated with XO/HX showed the cytotoxicity such as decreases in viability and DNA synthesis, a increase in lipid peroxidation. Cardiac endothelial cells pretreated with RCA extract protected the increase of lipid peroxidation by XO/HX. Cardiac endothelial cells pretreated with RCA extract inhibited the decrease of DNA synthesis by XO/HX. These results show that XO/HX elicits toxic effects in cultured cardiac endothelial cells derived from neonatal rat, and suggest that RCA extract is very effective in the prevention of XO/HX-induced toxicity.

Shear Performance on SFRC Beam Using Recycled Coarse Aggregate (순환골재를 사용한 SFRC 보의 전단성능)

  • Kim, Seongeun;Jeong, Jaewon;Kim, Seunghun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.6
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    • pp.189-196
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    • 2018
  • Degraded shear performance of reinforced concrete members with recycled coarse aggregate (RCA) compared to flexural strength is a problem. To address this, steel fibers can be used as concrete reinforcement material. In this study, the strength and deformation characteristics of SFRC beams using RCA were to be determined by shear tests. Major experimental variables include the volume fraction of steel fiber (0, 0.5%, 1%), the replacement rate of RCA (0%, 100%), and the shear span ratio (a/d = 1, 2). As a result of the experiment, the shear strength of the specimen increased as the rate of mixing steel fiber increased. For specimens with RCA and 1% steel fiber, the maximum shear strengths increased by 1.77 - 6.25% compared to specimens with normal coarse aggregate (NCA). On the other hand, at 0-0.5% steel fiber, the shear strengths of RCA specimens were reduced by 24.2% to 49.2% compared to NCA specimens. This indicates that reinforcement with 1% volume fraction of steel fiber greatly contributes to preventing shear strength reduction due to the use of RCA.

Comparison of the RCA Between China and KOR: From the Perspective of Value-Added

  • Xiaosong Jiao;Yingqi Cao;Lily Jiao;Chandaith Neak;Yaqian Zhang
    • Journal of Korea Trade
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    • v.26 no.4
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    • pp.23-38
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    • 2022
  • Purpose - This paper empirically explores the RCA of electrical equipment trade between China and Korea from the perspective of gross trade and value-added trade. The goal of this paper is to scan the electrical equipment's RCA, the decomposition of gross exports, and the impacts of an exerted shock. Design/methodology - We applied the domestic value-added method in measuring the RCA, which could be more accurate than traditional RCA since it excludes foreign value-added. Based on the research purpose, this paper follows the framework of Koopman, Wang, and Wei (2014)-as extended by Wang, Wei, and Zhu (2018). It extracts the data from the 2019 Multi-regional Input-Output (MRIO) databases compiled by the Asian Development Bank in January 2021. Findings - After rigorous examination, the main findings are as follows: First, the electrical equipment sector maintains a consistent comparative advantage in either assessing method. Second, China exports more gross goods of electrical equipment to the world than South Korea does, but there is a trade deficit with Korea. Third, South Korea and P.R. China are the most significant bilateral partners of foreign value-added sourcing. Finally, it is surprising that there is a shock on electrical equipment; the partner's service, as well as manufacturing sectors, would be affected. Originality/value - This paper explores the revealed comparative advantage between Korea and China from traditional gross export and value-added perspectives. Second, we apply the information from the 2019 MRIO database compiled by the Asian Development Bank in January 2021, reflecting the current situation. Third, this paper analyzes the electrical equipment and the impacts on other parties' sectors. Finally, we carry out the subjects that deserve to be investigated in the future.

Behavior of self-compacting recycled concrete filled aluminum tubular columns under concentric compressive load

  • Yasin Onuralp Ozkilic;Emrah Madenci;Walid Mansour;I.A. Sharaky;Sabry Fayed
    • Steel and Composite Structures
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    • v.51 no.3
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    • pp.243-260
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    • 2024
  • Thirteen self-compacting recycled concrete filled aluminium tubular (SCRCFAT) columns were tested under concentric compression loads. The effects of the replacement ratio of the recycled concrete aggregate (RCA) and steel fibre (SF) reinforcement on the structural performance of the SCRCFAT columns were studied. A control specimen (C000) was cast with normal concrete without SF to be reference for comparison. Twelve columns were cast using RCA, six columns were cast using concrete incorporating 2% SF while the rest of columns were cast without SF. Failure mode, ductility, ultimate load capacity, axial deformation, ultimate strains, stress-strain response, and stiffness of the SCRCFAT columns were studied. The results showed that, the peak load of tested SCRCFAT columns incorporating 5-100 % RCA without SF reduced by 2.33-11.28 % compared to that of C000. Conversely, the peak load of tested SCRCFAT columns incorporating 5-100% RCA in addition to 2% SF increased by 21.1-40.25%, compared to C000. Consequently, the ultimate axial deformation (Δ) of column C100 (RCA=100% and SF 0%) increased by about 118.9 % compared to C000. The addition of 2% SF to the concrete mix decreased the axial deformation of SCRCFAT columns compared to those cast with 0% SF. Moreover, the stiffness of the columns cast without SF decreased as the RCA % increased. In contrast, the columns stiffness cast with 2% SF increased by 26.28-89.7 % over that of C000. Finally, a theoretical model was proposed to predict the ultimate loads tested SCRCFAT columns and the obtained theoretical results agreed well with the experimental results.

Axial compressive behavior of partially encased recycled aggregate concrete stub columns after exposure to high temperatures

  • Jiongfeng Liang;Wanjie Zou;Liuhaoxiang Wang;Wei Li
    • Steel and Composite Structures
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    • v.52 no.2
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    • pp.121-134
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    • 2024
  • To investigate the compressive behavior of partially encased recycled aggregate concrete (PERAC) stub columns after exposed to elevated temperatures, 22 specimens were tested. The maximum temperature suffered, the replacement ratio of recycled coarse aggregate (RCA), the endurance time and the spacing between links were considered as the main parameters. It was found that the failure mode of post-heated PERAC columns generally matched that of traditional partially encased composite (PEC) columns, but the flange of specimens appeared premature buckling after undergoing the temperature of 400℃ and above. Additionally, the ultimate strength and ductility of the specimens deteriorated with the elevated temperatures and extended heating time. When 400℃< T ≤ 600℃, the strength reduction range is the largest, about 11% ~ 17%. The higher the replacement ratio of RCA, the lower the ultimate strength of specimens. At the temperature of 600℃, the ultimate strength of specimens with the RCA replacement ratio of 50% and 100% is 0.94 and 0.91 times than that of specimens without RCA, respectively. But the specimen with 50% replacement ratio of RCA showed the best ductility performance. And the bearing capacity and ductility of PERAC stub columns were changed for the better due to the application of links. When the RCA replacement ratio is 100%, the ultimate strength of specimens with the link spacing of 100 mm and 50 mm increased 14% and 25% than that of the specimen without links, respectively. Based on the results above, a formula for calculating the ultimate strength of PERAC stub columns after exposure to high temperatures was proposed.