• Structural Engineering and Mechanics
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• v.49 no.5
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• pp.631-644
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• 2014

Seismic assessment and retrofitting of existing structure is a complicated work that typically requires more sophisticated analyses than performing a new design. Before the implementation of a Code for seismic design of buildings (GBJ 11-89), not enough attention has been paid on seismic performance of structures and a great part of the existing reinforced concrete structures built in China have been poorly designed according to the new version of the same code (GB 50011-2010). This paper presents a case study of seismic assessment of a non-seismically designed reinforced concrete building in China. The structural responses are evaluated using the nonlinear static procedure (the so-called pushover analysis), which requires its introduction within a process that allows the estimation of the demand, against which the capacity is then compared with. The capacity of all structural members can be determined following the design code. Based on the structural performance, suitable retrofitting strategies are selected and implemented to the existing system. The retrofitted structure is analyzed again to check the effectiveness of the rehabilitation. Different types of retrofitting strategy are discussed and classified according to their complexity and benefits. Finally, a proper intervention methodology is utilized to upgrade this typical low-rise non-ductile building.

• Journal of Korean Society for Quality Management
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• v.40 no.4
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• pp.431-440
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• 2012

Purpose: In this paper we propose modified Notz designs which are useful to experimenters who want to adopt the sequential experimentation strategy and to estimate second-order regression model with as few experimental points as possible. Methods: We first present the design matrices and design points in two or three dimensional spaces for such small sized second-order designs as small composite, hybrid, and Notz designs. Modified Notz designs are proposed and compared with some response surface designs in terms of the total number of experimental points, the estimation capability criteria such as D- and A-optimality. Results: When sequential experimentation is necessary, the modified Notz designs are recommendable. Conclusion: The result of this paper will be beneficial to experimenters who need to do experiments more efficiently, especially for those who want to reduce the time of experimentation as much as possible to develop cutting-edge products.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.153-153
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• 2010

The world is moving towards a post-carbon society and needs clean and renewable energy for sustainable development. There are many methodological approaches which are helping this shift based on analyzed data about energy resources and which focus on limited types of energy including liquid fossil, solid fossil, gaseous fossil, and biomass (e.g. IPCC Guidelines, ISO 14064-1, WRI Protocol, etc.). We should also consider environmental impact (e.g. greenhouse gas emissions, water use, etc.) and the economic cost of the renewable energy to make a better decision. Recently, researchers have addressed the environmental impact of new technologies which include photovoltaics, wind turbines, hydroelectric power, and biofuel. In this work, we analyze the environmental impact with a carbon emission factor to present a correlation between $CO_2$ emission and the cost of energy resources standardized by the energy output. In addition, we reviewed Life Cycle Assessment (LCA) as another methodology. Researchers who are studying energy systems have ignored the impacts of entire energy systems, e.g. the extraction and processing of fossil fuels. In power sector, the assessment should include extraction, processing, and transportation of fuels, building of power plants, production of electricity, and waste disposal. Therefore LCA could be more suitable tool for energy cost and environmental impact estimation.

• The Journal of Fisheries Business Administration
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• v.41 no.2
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• pp.107-133
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• 2010

As policy makers are often concerned about dynamic effects of demand behavior and its welfare analysis by quantity changes, the paper shows how dynamic price formation systems can be built up to analyze the effect of policy options to the markets dynamically. The paper develops dynamic model of price formation for fish from the intertemporal optimization of the consumer choice problem. While the resulting model has a similar form of the error correction types of dynamic price formation system, it provides the rational demand behavior contrary to the myopic behavior of error correction demand models. The paper also develops appropriate tools of dynamic welfare analysis in quantity space using only short-run demand estimates both theoretically and empirically as a first attempt in the literature of price formation and fisheries. The empirical results of Korean fish markets show that the dynamic model and the welfare measures are reasonably plausible. The methodology and theory of this research can be applied and extended to the commodity aggregation, dynamic demand estimation, and dynamic welfare effects of regulation in the similar framework. Thus, it is hoped that this will enhance its applications to the demand-side economics.

• Journal of Positioning, Navigation, and Timing
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• v.3 no.1
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• pp.1-10
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• 2014

Recently, monitoring of two-body ground vehicles carrying extremely hazardous materials has been considered as one of the most important national issues. This issue induces large cost in terms of national economy and social benefit. To monitor and counteract accidents promptly, an efficient methodology is required. For accident monitoring, GPS can be utilized in most cases. However, it is widely known that GPS cannot provide sufficient continuity in urban cannons and tunnels. To complement the weakness of GPS, this paper proposes an accident monitoring method based on a monocular vision sensor. The proposed method estimates angular acceleration from a sequence of image frames captured by a monocular vision sensor. The possibility of using angular acceleration is investigated to determine the occurrence of accidents such as jackknifing and rollover. By an experiment based on actual measurements, the feasibility of the proposed method is evaluated.

• Journal of Distribution Science
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• v.15 no.10
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• pp.65-80
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• 2017

Purpose - The purpose of the present study is to discover success factors for small and medium-sized exporting enterprises and to derive factors that can positively influence the export of small and medium-sized enterprises. The ultimate goal is to contribute to the problem solution mentioned above. Research design, data, and methodology - A total of 258 filled-in questionnaires were collected; afterwards, frequency and cross tabulation analyses were conducted. The PPML analytic technique was applied to the core factors analyzed in Stages 1 and 2 to conduct regression analysis (cause and effect analysis and estimation method), thereby deriving success factors. Result - Based on detailed factors, a total of 15 success factors directly/indirectly involved in the success of export in small and medium-sized enterprises comprising 9 success factors, three positive effect factors for export, and three governments support policy factors were identified. Conclusions - The present paper is a rare empirical study paper that found and presented three detailed factors that positively influence on export and three government support policy factors, in addition to the above factors. Therefore, the results can be used by small and medium-sized enterprises that require not only previous studies, but also actual export success factor.

• Journal of Distribution Science
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• v.15 no.10
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• pp.41-50
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• 2017

Purpose - Online product review has become a crucial part of the online retailer's market performance for a wide range of products. This research aims to investigate how an individual reviewer's review frequency and timing affect her/his average attitude toward products. Research design, data, and methodology - To conduct reviewer-level analysis, this study uses 42,172 posted online review messages generated by 6,941 identified reviewers for 59 movies released in the South Korea from July 2015 to December 2015. This study adopts Tobit model specification to take into account the censored nature and the selection bias arising from the nature of J-shaped distribution of movie rating. Results - Our estimation results support that the negative impact of review frequency and timing on valence. Furthermore, review timing has an inverted-U relationship with the user's average valence and enhance the negative effect of review frequency. Conclusions - This study contributes to the growing literature on the understanding how eWOM is generated at the individual consumer level. On the basis of the main empirical findings, this study provides insights into building a recommendation system in online retail store based on the consumer's review history data - frequency, timing, and valence.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.1
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• pp.29-36
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• 2014

In industrial facilities sites, the conventional method determining the earthquake magnitude (M) using earthquake ground-motion records is generally not applicable due to the poor quality of data. Therefore, a new methodology is proposed for determining the earthquake magnitude in real-time based on the amplitude measures of the ground-motion acceleration mostly from S-wave packets with the higher signal-to-ratios, given the Vs30 of the site. The amplitude measures include the bracketed cumulative parameters and peak ground acceleration (As). The cumulative parameter is either CAV (Cumulative Absolute Velocity) with 100 SPS (sampling per second) or BSPGA (Bracketed Summation of the PGAs) with 1 SPS. The arithmetic equations to determine the earthquake magnitude are derived from the CAV(BSPGA)-As-M relations. For the application to broad ranges of earthquake magnitude and distance, the multiple relations of CAV(BSPGA)-As-M are derived based on worldwide earthquake records and successfully used to determine the earthquake magnitude with a standard deviation of ${\pm}0.6M$.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1527-1534
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• 2016

Online voltage stability monitoring using real-time measurements is one of the most important tasks in a smart grid system to maintain the grid stability. Loading margin is a good indicator for assessing the voltage stability level. This paper presents an Extreme Learning Machine (ELM) approach for estimation of voltage stability level under credible contingencies using real-time measurements from Phasor Measurement Units (PMUs). PMUs enable a much higher data sampling rate and provide synchronized measurements of real-time phasors of voltages and currents. Depth First (DF) algorithm is used for optimally placing the PMUs. To make the ELM approach applicable for a large scale power system problem, Mutual information (MI)-based feature selection is proposed to achieve the dimensionality reduction. MI-based feature selection reduces the number of network input features which reduces the network training time and improves the generalization capability. Voltage magnitudes and phase angles received from PMUs are fed as inputs to the ELM model. IEEE 30-bus test system is considered for demonstrating the effectiveness of the proposed methodology for estimating the voltage stability level under various loading conditions considering single line contingencies. Simulation results validate the suitability of the technique for fast and accurate online voltage stability assessment using PMU data.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.1
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• pp.137-147
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• 2017

Wartime warship damage rate indicates how much damage of friend warships shall have occurred during naval battles accomplished under specific war operational plans. The wartime damage rate analysis provides the baseline of wartime resources requirements. If wartime damage rate is overestimated, the national finance will get to negative effects because of exceeding the budget for inventory, operation, and maintenance of resources. Otherwise, if wartime damage rate is underestimated, the national defense will lose in the war because of lack of critical resources. In this respect, it is important to estimate the wartime damage rate accurately and reasonably. This paper proposes a systematic procedure to estimate the wartime warship damage rate. The procedure consists of five steps; force analysis, operation plan analysis, input variable definition, simulation modeling, and output analysis. Since the combat simulation model is regarded as the main tool to estimate damage rate, the procedure is focused on the development of model and experiments using the model. A case study with virtual data is performed to demonstrate the effectiveness of the developed procedure.