• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.25-34
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• 1999

In this study, the sliding wear in spur gears, using Archard's wear model, is analyzed. Formulas of tooth sliding wear depth along the line of action are derived. The tooth profile is modified Id make a smooth transmission of the normal loads and the cylinder profile for reducing the pressure spike is suggested. The sliding wear rate is calculated with these profiling results. We expect these modification methods to contribute to the reduction of sliding wear in the root and the tip of tooth and tooth edge.

• Asia-Pacific Journal of Business
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• v.14 no.4
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• pp.413-429
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• 2023

Purpose - The purpose of this study is to investigate the determinants of consumers' inflation expectations using consumers' inflation perceptions and the sub-components of consumer price index (CPI) basket in South Korea based on a consumer survey conducted by the Bank of Korea (BOK). Design/methodology/approach - Using Carroll's (2003) epidemiological model, we analyzed data from January 2013 to January 2023, resulting in a data set of 121 observations for both inflation perceptions and inflation expectations. This study focuses only on aggregate inflation expectations and perceptions because of data availability from the BOK. Findings - Professionals' forecasts play a major role in forming consumers' inflation expectations, whereas the actual headline CPI and consumers' inflation perceptions do not. These results remain robust when including the sub-components of the CPI basket in the analysis. Research implications or Originality - It would be the most efficient way to suppress professionals' expected inflation in fighting against a substantial spike in consumers' inflation expectations. To guide consumers' inflation expectations based on BOK's inflation targeting, the bank needs to consider professionals' forecasts in devising monetary policies.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.58-65
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• 2004

Thermal and structural finite element analyses were performed for the turbopump turbine bladed disk model with shroud of a liquid rocket engine. The only 1/80 part model was analyzed which consists of 3D eight node isoparametric solid elements. The applied loading history consists of a startup condition with a thermal spike and a steady state. Heat transfer coefficient on the blade was predicted using the commercial Navier-Stokes solver, Fluent. Transient thermal responses during startup and steady states were calculated using a 3D finite element code developed. Maximum stress and shroud tip displacement under the influence of centrifugal and thermal loading were also determined.

• Progress in Medical Physics
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• v.5 no.1
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• pp.41-53
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• 1994

The accurate localization of electrical sources in the brain is one of the most important questions in EEG, especially in the analysis of evoked responses and of epileptiform spike activity. A detailed simulation study of single dipole source estimation based on EEG is given in this paper. The effects of dipole model parameters on single dipole source tracing in EEG are examined in some detail using the Monte Carlo simulation. The error of source localization is found to be greatly influenced by how the electrodes are distributed over the head and the number of them.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1731-1737
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• 2007

The Korea electricity wholesale market is operated under the cost-based-pool system and the government regulation to the new generation capacities in order to insure the resource adequacy. The goal of government's regulation is the electricity market stability by attracting proper generation investment while keeping the reliability of system. Generation companies must mandatory observe that government plan by now. But if the restructuring is to be complete, generation companies should not bear any obligation to invest unless their profitability is guaranteed. Namely the investors' behavior will be affected by the market prices. In this paper, the system dynamics model for Korea wholesale electricity market to examine whether competitive market can help to stabilize is developed and analyzes the investors behavior. The simulation results show that market controlled by government will be operated stable without resulting in price spike but there is no lower price because of maintaining the reasonable reserve margin. However, if the competition is introduced and the new investment is determined by the investor's decision without government intervention, the benefits from lower wholesale price are expected. Nevertheless, the volatility in the wholesale market increases, which increases the investment risks.

• ETRI Journal
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• v.27 no.6
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• pp.759-767
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• 2005

This research is to substantially analyze the economic value of portable Internet (WiBro), WCDMA High Speed Downlink Packet Access (HSDPA), WiBro+VoIP, and WiBro+DMB regarded as the next generation of broadcasting. Based on the empirical analysis of economic values, we provide the optimal paths of converged communications and broadcasting services related to WiBro. 1,000 Internet users in the Seoul and Gyeonggi areas were surveyed in their homes. The collected survey was calculated as an accurate economic value distribution for relevant services, and the average and mean were taken using a parametric logit model, semi-parametric Spike model, and nonparametric Turnbull and Kernel estimations in order to analyze the contingent economic value of the amount offered to the subjects of the analysis. The contingent value analysis results varied slightly according to the different methodologies; however, all showed the following common features. The economic value of WiBro, Internet-based WCDMA, VoIP, and DMB with WiBro appeared to be similar. Therefore, if WiBro and WCDMA (HSDPA) form a competitive relationship, the types of bundled services offered as portable Internet service and the supply point of such bundled services are expected to emerge in a strategic plan for stimulating service markets and the prior occupation of the market.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.1
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• pp.124-134
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• 2019

As the types of North Korea's provocation are diverse and unexpectable in the costal area, ROK navy needs to develop countermeasures, such as costal defence guided rockets. Recently ROK navy developed the PKX-B which is equipped with the new 130 mm guided rocket. The most popular rockets are LOGIR for short range targets, 130 mm guided rocket for middle range targets and Spike-NLOS for long range targets. As various guided rockets are developed, it is required to develop a guided rocket analysis model and it's analysis methodology. In addition, these guided rockets can be installed on any platforms; ground vehicle, aircraft and warship. The paper proposes systematic methodology to estimate the operational effectiveness of costal defence guided rockets. A case study exploiting the ARENA simulation model is explained to demonstrate the implementation of the proposed methodology.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.107-114
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• 2021

Recently artificial intelligence technology has been introduced in various fields and various machine learning models have been operated in various frameworks as academic interest has increased. However, these frameworks have different data formats, which lack interoperability, and to overcome this, the open neural network exchange format, ONNX, has been proposed. In this paper we describe how to transform multiple machine learning models to ONNX, and propose algorithms and inference systems that can determine machine learning techniques in an integrated ONNX format. Furthermore we compare the inference results of the models before and after the ONNX transformation, showing that there is no loss or performance degradation of the learning results between the ONNX transformation.

• Journal of Energy Engineering
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• v.22 no.3
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• pp.270-282
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• 2013

Combustible waste into energy policy is an effective method to respond to climate change and depletion of fossil fuels. Combustible waste into energy is the process of generating energy in the form of electricity and/or heat from the combustible waste such as vinyl, paper and plastic. This study tries to estimate the external benefit of enhancing the ratio of combustible waste into energy to primary energy from 1.89% to 5% using contingent valuation(CV) method. To this end, we report the results from a CV survey to elicit the willingness to pay (WTP) for combustible waste into energy. A CV survey of 500 households was conducted in the Seoul by using person-to-person interviews. Thus, the procedures of applying and the findings from the one-and-one-half bounded dichotomous choice spike model used to deal with the zero WTP responses are provided in the paper. The results show that the average WTP is estimated to be 2,724 won per household per month and statistically significant at the 5% level. Expanding the value to the Seoul gives us an aggregate value of 13.7 billion won per year.

• Journal of Korea Technology Innovation Society
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• v.16 no.1
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• pp.20-40
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• 2013

A project of developing marine environmental risk assesment and management technology was proposed to improve the level of marine environmental management research. This paper attempts to measure the non-market benefits of the project. To this end, the dichotomous choice contingent valuation method is used. In particular, recently proposed one and one-half bounded model is applied. The model can reduce the potential for response bias comparing to the double bounded model while maintaining much of its efficiency. Moreover, in order to deal with zero WTP observations, a spike model is adjusted for our data. A survey of randomly selected 600 households was implemented and the respondents were asked in person-to-person interviews about how they would be willing to pay for implementing the project. Respondents overall accepted the contingent market and were willing to contribute a significant amount (2,663 won), on average, per household per year. The aggregate value of the project in the nation amounts to approximately 46.3 billion won per year. The figure 2.16 of cost-benefit ratio shows that economic validity of this technical development.