• Title/Summary/Keyword: Economic validity

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Modeling the polypropylene fiber effect on compressive strength of self-compacting concrete

  • Nazarpour, Mehdi;Asl, Ali Foroughi
    • Computers and Concrete
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    • v.17 no.3
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    • pp.323-336
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    • 2016
  • Although the self-compacting concrete (SCC) offers several practical and economic benefits and quality improvement in concrete constructions, in comparison with conventionally vibrated concretes confronts with autogenously chemical and drying shrinkage which causes the formation of different cracks and creates different problems in concrete structures. Using different fibers in the mix design and implementation of fibrous concrete, the problem can be solved by connecting cracks and micro cracks together and postponing the propagation of them. In this study an experimental investigation using response surface methodology (RSM) based on full factorial design has been undertaken in order to model and evaluate the polypropylene fiber effect on the fibrous self-compacting concrete and curing time, fiber percentage and fiber amount have been considered as input variables. Compressive strength has been measured and calculated as the output response to achieve a mathematical relationship between input variables. To evaluate the proposed model analysis of variance at a confidence level of 95% has been applied and finally optimum compressive strength predicted. After analyzing the data, it was found that the presented mathematical model is in very good agreement with experimental results. The overall results of the experiments confirm the validity of the proposed model and this model can be used to predict the compressive strength of fibrous self-compacting concrete.

A Study on Validity of Anti-PID Technology of Solar Cell for the High Reliability of Photovoltaics System (태양광 발전시스템의 신뢰성 향상을 위한 태양전지의 PID 저감 기술의 타당성 검토)

  • Baik, Sungsun;Baek, Seungyup;Jung, Tae-Wook;Cho, Jin-Hyng
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.36 no.2
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    • pp.32-38
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    • 2013
  • In recent years, anti-PID (Potential Induced Degradation) technologies have been studied and developed at various stages throughout the solar value chain from solar cells to systems in an effort to enhance long-term reliability of the photovoltaics (PV) system. Such technologies and applications must bring in profits economically for both manufacturers of solar cell/module and investors of PV systems, simultaneously for the development of the PV industry. In this study two selected anti-PID technologies, ES (modification of emitter structure) and ARC (modification of anti-reflective coating) were compared based on the economic features of both a cell maker with 60MW production capacity and an investor of 1MW PV power plant. As a result of this study, it is shown that ARC anti-PID technology can ensure more profits over ES technology for both the cell manufacturer and the investor of PV power plant.

A Study on Factors Affecting the Satisfaction of Public Bicycle System (공공자전거 시스템 만족도에 영향을 미치는 요인에 관한 연구)

  • Oh, Jae Sung;Kim, Myung Soo;Lee, Chang Hee
    • International Journal of Highway Engineering
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    • v.16 no.2
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    • pp.107-118
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    • 2014
  • PURPOSES : The purpose of study is to come up with ideas to improve both the use of the public bicycle and the practicality of the public bicycle system as well. METHODS : The study carried out an analysis on factors which would influence user's satisfaction by using a structural equation and then, discussed what the current public bicycle system should do to make improvements of its own. In order to Satisfaction of the public bicycle system("Tashu") in Daejeon city survey was conducted users and was based on statistical analysis SPSS 20 program, structural equation modeling program AMOS 20 was used for analysis. In addition, the reliability and validity of each question was conducted verification, to verify the hypothesis using structural equation model. RESULTS : According to the results of the analysis with the structural equation used, the connectivity, the convenience, the economic efficiency and the reliability in order were observed to have an influence on the satisfaction of the users CONCLUSIONS : The connectivity turned out to be a factor that would have the greatest concern with the satisfaction of the users. This finding was, therefore, interpreted that people who would ride the public bicycles understand them as more of a transit system that would take them, the people themselves, to another transfer rather than as some immediate transit system.

Practices and Legal Issues of Online Arbitration in China - focused on Online Arbitration of CIETAC (중국의 온라인중재 운용과 법적문제에 관한 연구 - CIETAC의 온라인중재를 중심으로)

  • Cha, Kyung-Ja;Choi, Sung-Il
    • Journal of Arbitration Studies
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    • v.20 no.2
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    • pp.131-149
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    • 2010
  • Since the Arbitration Law of China took effect in 1995, arbitration has grown with the economy. At the end of 2009, there were 202 arbitration institutions in China. Among them, China International Economic and Trade Arbitration Commission(CIETAC) has adopted online arbitration and has settled internet domain name disputes since 2001. CIETAC Domain Name Dispute Resolution Center(DNDRC) has accumulated abundant experiences of online arbitration in the field of domain name disputes. Based on those experiences, on 1 May 2009, CIETAC implemented the CIETAC Online Arbitration Rules(Rules') to regulate the resolution of e-business disputes as well as other business disputes. With this background, this article aims to study the status quo, practices and issues of online arbitration conducted by CIETAC. For the purpose of the article, a general picture of online arbitration is outlined first, followed by introducing the steps of the online arbitration procedure. According to the 'Rules', the entire arbitration process is conducted using online communication methods which are cost-effective and efficient. To facilitate the development of online arbitration, legal barriers need to be removed. This article considers main legal issues of online arbitration in China and proposes amendment to Chinese Arbitration Law, in particular, the recognition of the validity of electronic arbitration agreements and awards.

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A study on the technology life-cycle using patent information (특허정보를 이용한 기술수명주기 평가에 관한 연구)

  • Yoo Sung-Hee;Jeong Hye-Soon;Kim Heon
    • The Journal of Information Technology
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    • v.6 no.3
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    • pp.75-85
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    • 2003
  • It is highly required to evaluate the economic value of technology in many decision making of the technology management area, for example, technology acquisition, transfer, and investments. Also evaluating the performance of R&D objectively is very important subject in the public side. So, developing the objective technology evaluation system has much usefulness in practice. In many studies, the patent information has been suggested to the valid measurement for evaluation of technology. The purpose of this study is to explore the validity of patent information as a measurement of technology evaluation.

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A Study on a Control Method for Small BLDC Motor Sensorless Drive with the Single Phase BEMF and the Neutral Point (소형 BLDC 전동기 센서리스 드라이브의 단상 역기전력과 중성점을 이용한 제어기법 연구)

  • Jo, June-Woo;Hwang, Don-Ha;Hwang, Young-Gi;Jung, Tae-Uk
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.9
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    • pp.1-7
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    • 2014
  • Brushless Direct Current(BLDC) Motor is essential to measure a rotor position because of that this motor type needs to synchronize the rotor's position and changeover phase current instead of a brush and commutator used on the existing dc motor. Recently, many researches have studied on sensorless control drive for BLDC motor. The conventional control methods are a compensation value dq, Kalman filter, Fuzzy logic, Neurons neural network, and the like. These methods has difficulties of detecting BEMF accurately at low speed because of low BEMF voltage and switching noise. And also, the operation is long and complex. So, it is required a high-performance microprocessor. Therefore, it is not suitable for a small BLDC motor sensorless drive. This paper presents control methods suitable for economic small BLDC motor sensorless drive which are an improved design of the BEMF detection circuit, simplifying a complex algorithm and computation time reduction. The improved motor sensorless drive is verified stability and validity through being designed, manufactured and analyzed.

A Comparative Study of Korean and the US College Female Students′ Clothing Buying Behavior

  • Hwang, Choon-Sup;Kim, Sun-Ah
    • International Journal of Costume and Fashion
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    • v.4
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    • pp.47-61
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    • 2004
  • This study analyzed the buying patterns of American and Korean female college students in terms of criteria for clothing selection; store preferences; criteria for store selection; fashion information sources; expressions of customer dissatisfaction; purchasing frequency and motivations for purchasing clothes. The study was implemented through self-administered questionnaires which were back translated for validity. The samples consisted of 730 female college students majoring in the fields related to clothing and textiles: 310 U.S. and 412 Korean students. Likert scales were used for most measures with 1=never or very unimportant and 5=always or very important. Data were analyzed by factor analysis, analysis of covariance, Duncans multiple comparison, and t-test. Results are as follows: 1) Design factor was the most important criteria in clothing selection with no differences between country groups. There were, however, significant differences for psychological exhibition factors, practical and economic factors. 2) Both groups preferred specialty and department stores, with department stores more popular in Korea. 3) Merchandise was the most important store selection criterion and fashion magazines and self-experience were rated as the most important information sources for the both groups. 4) Korean group expressed their dissatisfaction with and observable problem with a product before purchase more often than U.S. group, but the U.S. group was more vocal about color loss or shrinkage after care procedures. 5) Some clear differences between the two countries emerged. Marketers targeting American consumers should pay more attention to practicality and service; to Korean consumers more symbolic meaning of products.

Development and Validation of Korea Midlife Family Resilience Scale(KMFRS) (한국 중년기 가족 레질리언스 척도 개발 및 타당화)

  • Park, Hea Rhan;Jeon, Gwee-Yeon
    • Korean Journal of Human Ecology
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    • v.23 no.6
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    • pp.1013-1033
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    • 2014
  • This study attempted to develop a valid and reliable instrument capable of measuring Korea midlife family resilience (The Korea Midlife Family Resilience Scale: KMFRS). An exploratory, non-experimental, cross-sectional, and quantitative design was used to develop and validate the KMFRS. A tentative factor structure of family resilience and an item pool of the scale were constructed through a comprehensive literature review and personal interview. The pilot study was conducted with 424 middle aged adults(40~59) to select items for a scale, resulting in a preliminary scale composed of 70 items. In the main study, the preliminary scale was administered to a national representative sample of 562 middle-aged Korean adults. The scale was filtered into 40 items by the item analysis and an exploratory factor analysis, resulting in 6 factors: Family Connectedness & Problem Solving, Family's Positive Perception of Adversity, Family's Economic Stability, Family Religion & Spirituality, Support of Extended Family, and Support of Friends & Neighbors. These 6 factors explained 61.82% of total variance. The findings of the current study indicate substantial support for the reliability and the validity of the KMFRS. Other challenges and suggestions for future research on family resilience scale are discussed.

Carbon dioxide emissions, GDP per capita, industrialization and population: An evidence from Rwanda

  • Asumadu-Sarkodie, Samuel;Owusu, Phebe Asantewaa
    • Environmental Engineering Research
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    • v.22 no.1
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    • pp.116-124
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    • 2017
  • The study makes an attempt to investigate the causal nexus between carbon dioxide emissions, GDP per capita, industrialization and population with an evidence from Rwanda by employing a time series data spanning from 1965 to 2011 using the autoregressive distributed lag model. Evidence from the study shows that carbon dioxide emissions, GDP per capita, industrialization and population are co-integrated and have a long-run equilibrium relationship. Evidence from the Granger-causality shows a unidirectional causality running from industrialization to GDP per capita, population to carbon dioxide emissions, population to GDP per capita and population to industrialization. Evidence from the long-run elasticities has policy implications for Rwanda; a 1% increase in GDP per capita will decrease carbon dioxide emissions by 1.45%, while a 1% increase in industrialization will increase carbon dioxide emissions by 1.64% in the long-run. Increasing economic growth in Rwanda will therefore reduce environmental pollution in the long-run which appears to support the validity of the environmental Kuznets curve hypothesis. However, industrialization leads to more emissions of carbon dioxide, which reduces environment, health and air quality. It is noteworthy that the Rwandan Government promotes sustainable industrialization, which improves the use of clean and environmentally sound raw materials, industrial process and technologies.

A Comparative Study on Change Circumstances in International Commercial Contracts (무역계약상 사정변경에 관한 비교법적 고찰)

  • Oh, Hyon-Sok
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.44
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    • pp.57-84
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    • 2009
  • This Study attempts to compare and analyze on Principle of Change Circumstances under th CISG, PICC and PECL which are covered international commercial contract. In many international commercial contract, time is very important because delays in performance are sanctioned heavily by substantial penalty clauses. When change in circumstances affects contract performance, the contract will often not be suspended or terminated. Therefore, principle of change circumstances is being prepared of fluidity of contract environment and its effect in general. Taking into consideration the problems relating to the renegotiation or adaptation in the cases of radical change of circumstances where the CISG applies, it is suggested that the contracting parties should make clear their intentions, that is, whether they will provide for the possibility of renegotiation where the price of goods has been altered by inserting a hardship clause or for the possibility of mutual discharge from liability in the cases of economic impossibility or hardship by inserting a force majeure clause. Such provision will be desirable especially in situations where there is a long term contract, the price of goods sold tends to fluctuate in the international commerce, or where especially in contracts subjected to arbitration, the parties subject their contract to legal sources or principles of supranational character. Therefore, this study has shown that the hardship provisions in the CISG, PICC and PECL has similarities to each a validity defense and an excuse defense. it was provisions that CISG governs this issue in Article 79, PICC Article 6.2.1, 6.2.2, 6.2.3 and PECL Article 6.111.

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