• Journal of Information Technology Services
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• v.21 no.4
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• pp.91-103
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• 2022

This study proposes a model for predicting contracted power using electric power data collected in real time from convenience stores nationwide. By optimizing the prediction model using machine learning, it will be possible to predict the contracted power required to renew the contract of the existing convenience store. Contracted power is predicted through the XGBoost regression model. For the learning of XGBoost model, the electric power data collected for 16 months through a real-time monitoring system for convenience stores nationwide were used. The hyperparameters of the XGBoost model were tuned using the GridesearchCV, and the main features of the prediction model were identified using the xgb.importance function. In addition, it was also confirmed whether the preprocessing method of missing values and outliers affects the prediction of reduced power. As a result of hyperparameter tuning, an optimal model with improved predictive performance was obtained. It was found that the features of power.2020.09, power.2021.02, area, and operating time had an effect on the prediction of contracted power. As a result of the analysis, it was found that the preprocessing policy of missing values and outliers did not affect the prediction result. The proposed XGBoost regression model showed high predictive performance for contract power. Even if the preprocessing method for missing values and outliers was changed, there was no significant difference in the prediction results through hyperparameters tuning.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.75-81
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• 2022

Under the government's principle of paying for emissions, the RFID-based pay-as-you-go system, which charges fees in proportion to emissions, was fully implemented in 2012. As of the end of 2018, the penetration rate is about 40% based on 149 local governments and multi-family apartments nationwide. The introduction of equipment showed a reduction effect of about 20-30%. Problems with existing equipment also began to appear. This study tried to improve by applying and integrating the existing technologies to solve the fundamental problems of these inlets. In other words, the plan is to improve the environment around the food waste meter by changing the design so that the hopper goes deep into the food waste bin inside the food waste meter so that the food waste becomes full and is designed smoothly when replacing the collection container.

• Journal of Advanced Navigation Technology
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• v.27 no.1
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• pp.119-125
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• 2023

It is necessary to reduce aviation GHG(CO2) emission to ensure aviation sustainable development. Operational improvements may not contribute significantly to carbon reduction but it can sustatially reduce emission in a short term. ICAO has developed GANP and ASBU to optimize operations and countries are making efforts to expand infrastructure and develop technology. The legal barriers to operational improvement are based on the notion of state sovereignty under the Chicago Convention which allows countries to control inefficiencies based on borders or limit or prohibit the passage of aircraft. Chicago Convention does not grant unlimited freedom of air sovereignty and if the concept of state sovereignty is interpreted according to the times it is possible to achieve smooth operational improvement.

• Industry Promotion Research
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• v.8 no.3
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• pp.9-17
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• 2023

The purpose of this study is to look for the trends and rates of change of major passenger modes such as railway, subway, domestic shipping, domestic airline, international shipping and international airline. The data used were selected from the KOSIS, "Domestic Statistics, Statistics by Subject, Transportation and Logistics". The analysis period was 22 years from 1999 to 2020, and the annual rate of change from the previous year was calculated. In descriptive statistics, international shipping and international airlines showed relatively high volatility, whereas railway and subway showed low volatility. In the rise rate analysis, international air and international shipping dropped significantly from 539% and 368% in 2019 to 85% and 20% in 2020 due to Corona. International airline and international shipping fell significantly in 2020, but we expect them to rise again as the shock of Corona disappears in the future. Therefore, it seems that we need a project to prepare for this. International air and international shipping are expected to continue their upward trend as international trade picks up again and international travel regains its momentum.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.755-761
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• 2006

Though freight origin and destination data is essential for analysing transport investment and planning logistics facilities, the study on the establishment of the freight origin and destination data is very rare. The purpose of this study is to introduce a method on weight and expansion of sample freight data focusing on the Seoul metropolitan area. In particular, this study suggests the weight and expansion method which consider truck and commodity tonnage together. This paper also discuss the origin and destination trips in Seoul metropolitan area. This paper will contribute to establish more reliable freight origin and destination data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.609-615
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• 2008

A Pedestrian Space in the transit transfer center is compositively made of a variety of activities for pedestrians. The pedestrians avoid access to the transit transfer center and the revitalization of the transit transfer center is obstructed as the travel cost of the pedestrians increases. This study provides the pedestrians using the transit transfer center with the significant real-time routing service and helps the movement of pedestrians to minimize the economical loss considering the travel cost and congestion of the pedestrians in the transit transfer center. In this paper, we propose a solution to construct a spatial map for the pedestrians in the transit transfer center to receive the significant real-time routing service based on Ubiquitous technique which is big issue around the world.

• Asia Marketing Journal
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• v.7 no.1
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• pp.67-89
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• 2005

In recent decades, product variety has increased dramatically in most industries. Rapidly evolving technologies, global competition, and sophisticated customers have contributed to an increase in product variety in many industries. In this paper, I study the impact of product variety on several businesses in the supply chain through literature review. By study of literature. this paper presents the benefits and drawbacks of increasing product variety on functions performed in several departments, such as engineering, manufacturing, purchasing, logistics and marketing. It provides a brief overview of the various techniques like modularity, component sharing, and platform-based development, which are helpful in reducing the costs, when designing for variety. It also provides a brief overview of order processing, purchased component/part variety, which are helpful in reducing the purchasing costs, and customer satisfaction, market advantage, market share, competitive advantage and demand forecast, which are useful in impact of product variety on marketing. Future research directions are discussed.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.472-478
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• 2023

The usage of jet fuel has been increasing with increasing passenger and logistics movements under globalization. CO₂, which is the main global warming gas from aircraft, was charged about 3.5% of total global CO₂ emissions and 12% of transportation fuel emissions. For these reasons, a lot of governments and the international civil aviation organization (ICAO) are trying to reduce CO₂ emissions via the introduction of bio-jet fuel. In this paper, we showed the jet fuel properties, specifications, and presentative production methods of bio-jet fuel such as alcohol to jet (ATJ), oil to jet (OTJ), gas to jet (GTJ) and sugar to jet (STJ). Also, we described the status of global and domestic bio-jet fuel usage and the policy plan for efficient distribution.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.223-228
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• 2023

Sustainable energy supplies without the recharging and replacement of the charge storage device have become increasingly important. Among various energy harvesters, the triboelectric nanogenerator (TENG) has attracted considerable attention due to its high instantaneous output power, broad selection of available materials, eco-friendly and inexpensive fabrication process, and various working modes customized for target applications. In this study, the amount of voltage and current generated was measured by applying the PSD profile random vibration test of the electronic vibration tester and ISTA 3A according to the time of Anodized Aluminum Oxide (AAO) pore widening of the manufactured TENG device Teflon and AAO. The discharge and charging tests of the integrated module during the random simulated transport environment and the recognition distance of RFID were measured while agricultural products (onion) were loaded into the returnable folding plastic box. As a result, it was found that AAO alumina etching processing time to maximize TENG performance was optimal at 31 min in terms of voltage and current generation, and the integrated module applied with the TENG module showed a charging effect even during the continuous use of RFID, so the voltage was kept constant without discharge. In addition, the RFID recognition distance of the integrated module was measured as a maximum of 1.4 m. Therefore, it was found that the surface condition of AAO, a TENG element, has a great influence on the power generation of the integrated module, and due to the characteristics of TENG, the power generation increases as the surface dries, so it is judged that the power generation can be increased if the surface drying treatment (ozone treatment, etc.) of AAO is applied in the future.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.3 s.55
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• pp.110-118
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• 2009

The tunnel structure is widely used for transportation in the mountain area. To reduce the duration of construction and thus the expense, a tunnel excavation is often performed simultaneously with a tunnel lining in in-situ. However, cracking of the tunnel lining may occur arising from the vibrating impact in the excavation process. The present study concerns the role of steel fiber and nylon fibers in tunnel lining concrete to reduce the vibrating impact. As a result it was found that both the nylon fiber and steel fiber improved the durability and physical properties of concrete.