• The Journal of Information Systems
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• 제29권3호
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• pp.145-157
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• 2020

Purpose This study proposed an approach for predicting the efficiency rating of the cultural tourism festivals using DEA and machine learning techniques. The cultural tourism festivals are selected for the best festivals through peer reviews by tourism experts. However, only 10% of the festivals which are held in a year could be evaluated in the view of effectiveness without considering the efficiency of festivals. Design/methodology/approach Efficiency scores were derived from the results of DEA for the prediction of efficiency ratings. This study utilized BCC models to reflect the size effect of festivals and classified the festivals into four ratings according the efficiency scores. Multi-classification method were considered to build the prediction of four ratings for the festivals in this study. We utilized neural networks and SVMs with OAO(one-against-one), OAR(one-against-rest), C&S(crammer & singer) with Korea festival data from 2013 to 2018. Findings The number of total visitors in low efficient rating of DEA is more larger than the number of total visitors in high efficient ratings although the total expenditure of visitors is the highest in the most efficient rating when we analyzed the results of DEA for the characteristics of four ratings. SVM with OAO model showed the most superior performance in accuracy as SVM with OAR model was not trained well because of the imbalanced distribution between efficient rating and the other ratings. Our approach could predict the efficiency of festivals which were not included in the review process of culture tourism festivals without rebuilding DEA models each time. This enables us to manage the festivals efficiently with the proposed machine learning models.

• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.16-27
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• 2015

Holography technology which was developed by Dennis Gabor (1900~1979) in 1948 is a technology to record wave planes of actual 3D objects. It is known as the only technology which can express 3D information most perfectly close to human-friendly. Holography technology is widely used in advertisement, architecture and arts as well as science technology areas. Especially, digital holographic print which is an applied area is greatly used in military map, architecture map and cultural asset restoration by printing and reproducing 3D information. Holography is realized by recording and reproducing the amplitude and phase information on high resolution film using coherent light like laser. Recording materials for digital holographic printer are silver halide, photoresist and photopolymer. Because the materials have different diffraction efficiency according to film characteristics of each manufacturer, appropriate guide lines should be suggested through efficiency analysis of each film. This paper suggests appropriate guide lines through the diffraction efficiency measurement of silver halide which is a holographic printer recording medium. And the objective of this study is to suggest appropriate guide lines through diffraction efficiency analysis of Ultimate 08-C and PFG-03C which are commercially used. The experiment was prepared by self-diffraction efficiency system which measures the strength with the defector by penetrating RGB recording medium and concentrating diffracted beams through collimating lens. The experiment showed Geola's PFG-03C which is a silver halide for full color has price/performance advantage in optical hologram recording, but recording angles and reproduction angles are irregular for digital holographic printer recording. Ultimate's Ultimate08-C for full color shows its diffraction efficiency is relatively stable and high according to recording angles and laser wavelength.

• Journal of Korean Society of Water and Wastewater
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• 제18권2호
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• pp.201-207
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• 2004

Dissolved air flotation (DAF) is a solid-liquid separation process that uses fine rising bubbles to remove particles in water. Most of particle-bubble collision occurs in the DAF contact zone. This initial contact considered by the researchers to play a important role for DAF performance. It is hard to make up conceptual model through simple mass balance for estimating collision efficiency in the contact zone because coupled behavior of the solid-liquid-gas phase in DAF system is 90 complicate. In this study, 2-phase(gas-liquid) flow equations for the conservation of mass, momentum and turbulence quantities were solved using an Eulerian-Eulerian approach based on the assumption that very small particle is applied in the DAF system. For the modeling of turbulent 2-phase flow in the reactor, the standard $k-{\varepsilon}$ mode I(liquid phase) and zero-equation(gas phase) were used in CFD code because it is widely accepted and the coefficients for the model are well established. Particle-bubble collision efficiency was calculated using predicted turbulent energy dissipation rate and gas volume fraction. As the result of this study, the authors concluded that bubble size and recycle ratio play important role for flow pattern change in the reactor. Predicted collision efficiency using CFD showed good agreement with measured removal efficiency in the contact zone. Also, simulation results indicated that collision efficiency at 15% recycle ratio is higher than that of 10% and showed increasing tendency of the collision efficiency according to the decrease of the bubble size.

• International Commerce and Information Review
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• 제13권1호
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• pp.123-144
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• 2011

This study used a non-parametric linear program, Data Envelopment Analysis(DEA) to compare the efficiency of Korean and global container shipping companies from 2005 to 2009. The sample shipping companies were 7 Korean container shipping companies and 11 global container shipping companies. The main objective of our research is to compare their efficiency, as well as the changes in efficiency periodically according to the types of the container shipping companies. According to the periodical analysis, both Korean and Global container shipping companies showed a steady decrease in efficiency. The study showed that Korean container shipping companies have greater efficiency than their global rivals.

• International Area Studies Review
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• 제13권3호
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• pp.729-757
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• 2009

This paper examines if China' each province.city manages its organization well after China's WTO affiliation; and on the ground, judges how much each province city needs to improve. China's each province city data from 2002 to 2006 is used to evaluate technical efficiency by using the input-oriented CCR model and the input-oriented BCC model. Analytical results show that only Shanghai gets continuously the highest efficiency score from 2002 to 2006 and so the other provinces cities need to benchmark Shanghai to elevate their efficiency. There can be regional, cultural and emotional differences among the provinces cities but Tibet, Shaanxi, Gansu, Qinghai, Ningxia and Xinjiang get low efficiency scores even after China's WTO affiliation. The Chinese government can make use of efficiency evaluation results by DEA as basic materials in making economic development schemes in order to reduce these deviations as various minority races constitutes China and there are regional deviations of degree of economic development in China.

• Journal of Climate Change Research
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• 제7권1호
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• pp.85-93
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• 2016

This study the efficiency of greenhouse gas reduction of 'low carbon car collaboration fund' and its alternative 'control of average fuel efficiency and greenhouse gas', and 'improving driving behavior' were analyzed by using LEAP, long term energy analysis model. Total 4 scenarios were set, baseline scenario, without energy-saving activity, 'low carbon car collaboration fund' scenario, 'fuel efficiency improving scenario', and 'improving driving behavior' scenario. The contents of analysis were forecast of energy demand by scenario and application as well as reduction of greenhouse gas emission volume, and the period taken for analysis was every 1 year during 2015~2030. Baseline scenario, greenhouse gas emission volume in 2015 would be 7,935,697 M/T and 13,081,986 M/T in 2030, increased 64.8%. The analysis result was average annual increase rate of 3.4%. The expected average annual increase rate of other scenarios was, 'low carbon car collaboration fund' scenario 1.7%, 'fuel efficiency improving' scenario 3.0%. and 'improving driving behavior' scenario 3.4%. and these were each 1.7%, 0.3%. 0.3% reduce from baseline scenario. The largest reduction was 'low carbon car collaboration fund' scenario, and there after were 'fuel efficiency improving scenario', and 'improving driving behavior' scenario.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.128-130
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• 2016

The digital content industry is growing rapidly with the popularity of online content and mobile devices. This study estimates the technical efficiency of the online digital content industry, and identifies factors that could be causing inefficiency. Unlike most previous studies, which adopted input-oriented or output-oriented DEA model, this study employs non-oriented DEA model in order to deal with both input surpluses and output shortfalls. The input variables for the empirical analysis are number of companies and number of workers. The total sales is used as the output variables. The empirical results show that the technical efficiency of the online digital content industry is relatively low mainly due to the scale efficiency rather than the pure technical efficiency. This implies that industry-specific policies should be implemented in order to improve technical efficiency as well as to strengthen technological innovation capability. Therefore, it is expected that the results obtained in this study can be used as a good reference for helping the online digital content industry enhance their competitiveness.

• Journal of the Chungcheong Mathematical Society
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• 제27권1호
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• pp.133-143
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• 2014

A new three-step quadraparametric family of eighth-order iterative methods free from second derivatives are proposed in this paper to find a simple root of a nonlinear equation. Convergence analysis as well as numerical experiments confirms the eighth-order convergence and asymptotic error constants.

• Proceedings of the Acoustical Society of Korea Conference
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• 한국음향학회 1993년도 학술논문발표회 논문집 제12권 1호
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• pp.273-275
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• 1993

The throughput of conventional ARQ protocols can be improved by dynamically adapting the packet length. This protocol transmits packets with the length to maximize the transmission efficiency, based on the dynamic estimation of time-varying channel condition. A very simple adaptive scheme is presented. The results of a simulation show that the scheme performs well.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.7-8
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• 2008

It is well-known that one of the most serious problems of Orthogonal Frequency Divison Multiplexing (OFDM) is its high Peak-to-Average Power Ratio (PAPR) which seriously limits the power efficiency of High Power Amplifier (HPA). This paper introduces various methodologies to cope with this problem.