• The Journal of Asian Finance, Economics and Business
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• v.7 no.4
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• pp.173-183
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• 2020

This study has four objectives: (1) Identifying factors that affect customer satisfaction on online service quality of Tiki.vn, (2) Measuring the level of impact of the factors, (3) Testing the difference in satisfaction among groups of customers with different characteristics in terms of gender, age, income, academic level, and occupation, and (4) Proposing some managerial implications to improve the quality of online services by interviewing directly and online 200 individual customers who have shopped at Tiki.vn E-commerce platform for at least the last six months, using the convenient sampling method. This study analyzes the reliability of the scale through the Cronbach's alpha coefficient, Exploratory factor analysis, and Linear regression analysis. The findings identified four factors that influence positively customer satisfaction regarding the quality of online services in Tiki.vn E-commerce platform in the order of descending strength: (1) Trust, (2) Customer service, (3) Web design and (4) Safety. In addition, the results show no difference in customer satisfaction according to different academic levels, but in terms of occupation and income, gender, and age. The results show that the factors influencing most customer satisfaction are Reliability and Customer Service. Some managerial implications are then proposed to improve the quality of online shopping services at Tiki.vn.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.3
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• pp.551-569
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• 2024

With the rapid development of electric vehicles (EVs) industry, EV charging service becomes more and more important. Especially, in the case of suddenly drop of air temperature or open holidays that large-scale EVs seeking for charging devices (CDs) in a short time. In such scenario, inefficient EV charging scheduling algorithm might lead to a bad service quality, for example, long queueing times for EVs and unreasonable idling time for charging devices. To deal with this issue, this paper propose a Deep-Q-Network (DQN) based two-stage scheduling method for the large-scale EVs charging service. Fine-grained states with two delicate neural networks are proposed to optimize the sequencing of EVs and charging station (CS) arrangement. Two efficient algorithms are presented to obtain the optimal EVs charging scheduling scheme for large-scale EVs charging demand. Three case studies show the superiority of our proposal, in terms of a high service quality (minimized average queuing time of EVs and maximized charging performance at both EV and CS sides) and achieve greater scheduling efficiency. The code and data are available at THE CODE AND DATA.

• Journal of the Korean Society for Library and Information Science
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• v.34 no.4
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• pp.5-26
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• 2000

The purpose of this study was to measure performance of university libraries, especially investigating the components of service quality and their relationship to the customer satisfaction. The result of the study was summarized as follows: First, the factors on satisfaction of library service revealed 12 factors such as access of information, quality of employees, suitable collections, issues related to civil petitions, equipments and facilities, timeliness, operating hours, use of information technology, library user education, reference service, public relation and individual service. Second, the factors of library service on customer satisfaction showed the following primary factors: suitable collections, issues related to civil petitions, access of information, equipments and facilities, timeliness, public relation, reference service, operating hours, and individual service. Third, the components of library service on customwe satisfaction showed the following primary components: availability, the number of books and journals, facilities of air conditioning, public relation, usefulness of retrieval system, waiting time for Internet use, operating hour, speed of repairs, receipt of civil petitions, use of non-book materials.

• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.822-833
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• 2010

Temperature increase due to climate changes causes change of water temperature in rivers which results in change of water quality etc. and the change of river ecosystem has a great impact on human life. Analyzing the impact of current climate changes on air and water temperature is an important thing in adapting to the climate changes. This study examined the effect of climate changes through analyzing air temperature trend for Nakdong river basin and analyzed the elasticity of air-water temperature to understand the effect of climate changes on water temperature. For analysis air temperature trend, collecting air temperature data from the National Weather Service on main points in Nakdong river basin, and resampling them at the units of year, season and month, used as data for air temperature trend analysis. Analyzing for elasticity of air-water temperature, the data were collected by the Water Environment Information system for water temperature, while air temperature data were collected at the National Weather Service point nearest in the water temperature point. And using the results of trend analysis and elasticity analysis, the effect of climate changes on water temperature was examined estimating future water temperature in 20 years and 50 years after. It is judged that analysis on mutual impact between factors such as heat budget, precipitation and evapotranspiration on river water temperature affected by climate changes and river water temperature is necessary.

• Food Science and Preservation
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• v.22 no.1
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• pp.56-62
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• 2015

In this study, the quality characteristics of different drying methods of Aronia melanocarpa, which contains large amounts of bioactive substances, were investigated for the improvement of their practical use. During the drying period, the weight reduction was the highest with vacuum freeze drying (81.6%). The water content was reduced to the maximum level when vacuum freeze-drying was used. With regard to the color value measurement results, there were no significant differences in the $L^*$ value. Values of $a^*$ and $b^*$ were increased in vacuum freeze drying and cold air drying, but decreased in hot air drying. The hardness was increased dramatically after 36 hours of hot air drying, while with cold air drying, it increased slowly until 132 hr and increased rapidly after 132 hr. The dried yield was the highest with cold air drying (24.2%). As for the general component analysis results of Aronia melanocarpa, the moisture content was the lowest, and the crude protein and crude fat contents were the highest with vacuum freeze drying. No difference in pH value was shown among the dried Aronia melanocarpa obtained from the different drying methods, but the sugar content was the highest with vacuum freeze drying. The mineral content was the highest with cold air drying, and K, Ca, Mg, and Na were the major minerals. The free sugar content of dried Aronia melanocarpa was found to be 5.92~20.59 g/100 g, and the highest free sugar content was found with vaccum freeze drying.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.149-154
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• 2007

Now, in Korea, the performances of the building service equipment relay on the individual superintendent's share for the assessment of performance, fault detection, deterioration diagnosis of the building service equipment. As the result, very different quality of the performance or the durability of equipment is being obtained with his skill and effort and it is also not easy to assess that quality. This finally lead to the waste of labor force and the operating cost due to the high-cost, low-efficiency system. How to construct the N-BMS was considered to save energy, resource and to conserve performance of building service equipment. The FEMIS, facility, energy/environmental management & information system, for building service offer management process integrated with BAS, FMS and EMS and so on.

• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.723-729
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• 2007

The Ministry of Environment established a guide line in December 2006, "Indoor Air Quality Management guidelines in Public Facilities." As the items of the guideline, $CO_2$ (Carbon dioxide) and PM10 (particulate matter) is shown to Level 1 and 2. Therefore trains and subways are included. There are a lot of tunnels by the lay of mountains on KTX (Korean Train Express) service. HVAC (Heating Ventilating and Air-conditioning)-pressurization equipment on KTX is various functioning flaps blocking outside pressure waves. At that time, the fresh air is blocked by flap operation and the air is circulated by return air. In this study, we measured the time series of $CO_2$ and PM10 concentrations in the KTX passenger cabin during the train service of Gyongbu line (Seoul-Busan) and Honan line (Yongsan-Mokpo) from July 2006. Also, analyzed the air quality by operation of KTX HVAC-pressurization equipment in tunnel passing point. As a result, PM10 concentration was totally lower than the regulation values. However, $CO_2$ was highly correlated with several tunnels, such as Oksan-Otan, Godeung-Hyudae and Gaechak-Iijik tunnel. but, the indoor air quality of KTX train have been proved satisfy the recommendation the Ministry of Environment guidelines.

• ETRI Journal
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• v.45 no.5
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• pp.887-898
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• 2023

Aerial base stations (ABSs) seem promising to enhance the coverage and capacity of fifth-generation and upcoming networks. With the flexible mobility of ABSs, they can be positioned in air to maximize the number of users served with a guaranteed quality of service (QoS). However, ABSs may be overloaded or underutilized given inefficient placement, and user association has not been well addressed. Hence, we propose a three-dimensional ABS placement scheme with a delay-QoS-driven user association to balance loading among ABSs. First, a load balancing utility function is designed based on proportional fairness. Then, an optimization problem for joint ABS placement and user association is formulated to maximize the utility function subject to statistical delay QoS requirements and ABS collision avoidance constraints. To solve this problem, we introduce an efficient modified gray wolf optimizer for ABS placement with a greedy user association strategy. Simulation results demonstrate that the proposed scheme outperforms baselines in terms of load balancing and delay QoS provisioning.

• Journal of Korean Society of Transportation
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• v.25 no.1 s.94
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• pp.81-91
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• 2007

Incheon International Airport (IIAC) has been named "best airport worldwide" according to the AETRA Passenger survey Program that was jointly administered by Airports Council International (ACI) and the International Air Transport Association (IATA) in 2005. This paper identifies eight dimensions underlying the overall service qualify in passenger terminals. These eight elements were found from literature reviews through relevant documents. The research explains the linkage between the overall satisfaction with IIAC and five services that influence that satisfaction. The five services are the following: service quality of passenger terminals, commercial facility services, easy access by transportation, service quality of the airlines, and contributions to the community by IIAC. The data envelopment analysis (DEA) designed by Cook and Kress (CK Model) was used to maximize the efficiency of commercial facility services, easy access by transportation, service qualify of the airlines, and contributions to the community by IIAC because the model best provided practical plans for a more competitive airport. This paper has three significant results. First, it includes research of passenger terminal-oriented service quality. Second, the author researches service qualify focusing on a three-cornered relation among passengers, airline employees, and IIAC. Third, the paper contains research of service quality focusing on IIAC's employees.

• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.733-739
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• 2007

Demand for Sea & Air intermodal transport has increased between north-China costal cities and Incheon since China's international airline network was not established completely. It will be big opportunity for Incheon to be logistics hub of Sea & Air intermodal transport in the north-east Asia, musing large sea-air cargoes to be transferred at the port of Incheon. Therefore, this study aims to propose competitive strategy on Sea & Air intermodal transport system of Incheon. In this analysis results, this paper shows that sea & air cargoes rather from china to U.S. than from China to Europe is very significant, considering geographically for Incheon and is also devote to not only providing high quality services but also activating RFS(Road Feeder Service) system, enlarging toward Shanghai, Weihai, and Yantai.