• Journal of the Korean Home Economics Association
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• v.35 no.4
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• pp.31-46
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• 1997

The controversy between Lewis and Spanier's theory and Thomas and kleber's theory on marital satisfaction and marital stability was tested empirically. The results show that while marital satisfaction was the best predictor for marital stability the impact of alternative attractions and external pressures to remaim married was more complicated than both theories predicted depending on the nature of alternative attractions. Thomas and Kleber's theory was supported in most of groups Contrary to Lewis and Spanier's theory alternative atteractions did not negatively affect marital stability of marriages of high qulity. Contrary to both theories external pressures to remain married was not an important predictor of marital stability . In some cases high external pressures to remain married even lowered marital stability. The validity of both theories are discussed.

• Journal of Biosystems Engineering
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• v.34 no.3
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• pp.135-139
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• 2009

Harmful exhaust emissions of diesel engines are recognized as main causes of air pollution in these days. But, the direct injection diesel engine is widely used for sake of minimization on energy consumption. Because biodiesel fuel is a renewable and alternative fuel for a diesel engine, its usability is expanded. To investigate the effect of biodiesel fuel(extracted from rapeseed oil) on the characteristics of performance and exhaust emissions in an agricultural diesel engine, the biodiesel fuel derived from rapeseed oil was applied in this study. Smoke emission of esterified rapeseed oil was reduced remarkably by approximately 44.5% at 1500 rpm, full load in comparison with the commercial diesel fuel. The power, torque and brake specific energy consumption of the diesel engine showed very slight differences. It was concluded that esterified rapeseed oil could be utilized effectively as an alternative and renewable fuel for agricultural direct injection diesel engines.

• Journal of Biosystems Engineering
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• v.31 no.6 s.119
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• pp.457-462
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• 2006

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions from diesel engine are recognized main cause which influenced environment strong. In this study, the potential possibility of biodiesel fuel and oxygenates additives (dimethoxy methane) was investigated as an alternative fuel for a naturally aspirated direct injection diesel engine. The smoke emission of blending fuel (biodiesel fuel 90vol-% + DMM 10vol-%) was reduced in comparison with diesel fuel, that is, it was reduced approximately 70% at 2500 rpm, full load. But, power, torque and brake specific energy consumption didn't have no large differences. But, NOx emissions from biodiesel fuel and DMM blended fuel were increased compared with commercial diesel fuel.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.4
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• pp.81-94
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• 2013

Recently, the dramatical increasement of personal information infringement makes the government strongly enforce the laws. The Key-point of law enforcement is the DB encryption. Nevertheless, DB encryption is the one of the hardest thing in the organization's security measures. The purpose of this paper is suggesting alternative means of residence numbers and showing the possibility of indicator usage for safety measures. This research suggested the best ways to make a decision through a before and after comparison of the DB encryption cost of the inherent identification number elimination in "Social Welfare consolidation service system". When this research result was applied in "Happiness-e-Um system", we found that the alternative means are more efficient than the residence number for encryption cost, system revision time and so on.

• Journal of Environmental Science International
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• v.9 no.6
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• pp.489-494
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• 2000

This research focused on the priotity decision for establishment sriteria on the effects which environmental sculptures in urban area. The analysis performed in this study used the AHP(Analytic Hierarchy Process) that is recognized as a useful decision-making tool to select and evaluate alternatives through pairwise comparison in the context of hierarchical decision structure. The results obtained from the analysis drawn by collecting the professional opinions of 5 experts for environmental sculptures are as follows: 1. The orders of establish criteria priorities on environmental sculptures were harmony of environment> symbol> public> function. The harmony of environment was the most important priority because it showed the highest weight of criteria. 2. The alternative priorities of environmental sculptures were the meaning of work>setting place> social contribution> physical quality .The meaning of work showed the highest change in the weight of alternative. 3.The sensitivity analysis of environmental sculptures demonstrated that the rate of change in the alternative priorities of the public was stabilized although the criteria importance varied, while the harmony of environment, the symbol intimated and function of priorities has their rates of weight changed if the criteria priorities were high.

• Transactions of The Korea Fluid Power Systems Society
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• v.5 no.4
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• pp.17-25
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• 2008

This study presents an analytical model of the pneumatic circuit of an air suspension system to analyze the characteristics of vehicle height control. The analytical model was developed through the co-simulation of Simulink(air spring) and HyPneu(pneumatic circuit). Variant effective area of air spring and flow coefficients of pneumatic valves were estimated experimentally prior to the system test, and utilized in simulation. One-comer test apparatus was established using the components of commercial air suspension products. The results of simulation and experiment were so close that the proposed analytical model in this study was validated. However the frictional loss of conduit and heat dissipation which were ignored in this study need to be considered in future study. As an application example of proposed analytical model, an alternative pneumatic circuit of air suspension to conventional WABCO circuit was evaluated. The comparison of simulation results of WABCO circuit and alternative circuit show that proposed analytical model of co-simulation in this study is useful for the study of pneumatic system of automotive air suspension.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.3-10
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• 2022

An estimated investment gap of $176 billion needs to be filled over the next ten years to improve America's inland waterway transportation systems. Many of these infrastructure systems are now beyond their original 50-year design life and are often behind in maintenance due to funding constraints. Therefore, long-term maintenance strategies (i.e., asset management (AM) strategies) are needed to optimize investments across these waterway systems to improve their condition. Two common AM strategies include policy-driven maintenance and performance-driven maintenance. Currently, limited research exists on selecting the optimal AM approach for managing inland waterway transportation assets. Therefore, the goal of this study is to provide a decision model that can be used to select the optimal alternative between the two AM approaches by considering key uncertainties such as asset condition, asset test results, and asset failure. We achieve this goal by addressing the decision problem as a single-criterion problem, which calculates each alternative's expected value and certain equivalence using allocated monetary values to determine the recommended alternative for optimally maintaining navigable waterways. The decision model considers estimated and predicted values based on the current state of the infrastructure. This research concludes that the performance-based approach is the optimal alternative based on the expected value obtained from the analysis. This research sets the stage for further studies on fiscal constraints that will effectively optimize these assets condition.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.248-251
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• 2003

The ACI 318 stress block parameters have been closely examined for validity of their values in evaluation of flexural strength and deformability. For this the conventional definition of stress block has been used. The comparison of parameter values between ACI stress blocks and the exact approach implies that an alternative idealization other than the rectangular stress block may be required.

• Korean Journal of Logic
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• v.8 no.1
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• pp.1-22
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• 2005

This paper provides a comparison of three fundamentally different approaches to the issue of ontological commitment. It argues that despite superficial similarities on either side, Buridan's approach provides an intriguing third alternative to the two commonly recognized modern approaches.

• Journal of The Korean Association For Science Education
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• v.26 no.7
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• pp.798-804
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• 2006

In this study, we investigated students' responses to a discrepant event and an alternative hypothesis which had been presented in the conceptual change processes from the phlogiston theory to the oxygen theory, and compared them with scientists' responses. The data concerning scientists' responses to the discrepant event and the alternative hypothesis were gathered from the relevant literature on the history of science. Subjects were 148 eighth graders who possessed the target misconception about combustion through a preconception test. After having been presented with the discrepant event and the alternative hypothesis, students were asked to respond to the test of response to discrepant event. Although similar types of responses were obtained from both scientists and students, there was also a clear difference. Scientists tended to focus on explaining the problems of the discrepant event, whereas students tended to ignore and/or exclude the discrepant event in order to maintain their previous beliefs. Only a few students were also found to change their beliefs after having been presented with the alternative hypothesis.