• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.6
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• pp.1259-1266
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• 2013

Nowadays, the databases are getting larger and larger. As the company has difficulty in managing the database, they want to outsource the database to the cloud system. In this case the database security is more important because their database is managed by the cloud service provider. Among database security techniques, the encryption method is a well-certified and established technology for protecting sensitive data. However, once encrypted, the data can no longer be easily queried. The performance of the database depends on how to encrypt the sensitive data, and on the approach for searching, and the retrieval efficiency that is implemented. In this paper we propose the new suitable mechanism to encrypt the database and lookup process on the encrypted database under control of the cloud service provider. This database encryption algorithm uses the bloom filter with the variable keyword based index. Finally, we demonstrate that the proposed algorithm should be useful for database encryption related research and application activities.

• Journal of Service Research and Studies
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• v.5 no.1
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• pp.35-43
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• 2015

Regional comparative analysis for the variability of young man's employment indexes is important to unemployment or employment policy data of central and local government. Through the result of comparative analysis, central and local government can use differentiated policies for the regions and keep the efficiency for the application of detailed policy. In this study, based on economically active population survey data which consider economically active population rate, employment population rate and unemployment rate as typical employment indexes of young man, we analyzed the variability of these indexes by metropolitan cities and province regions using coefficient of variation. Also we proposed the largest index in variability of three employment indexes, and proposed the city and province region with the largest variability for each employment index.

• Journal of Digital Convergence
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• v.14 no.7
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• pp.185-191
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• 2016

Recently, various medical services are provided with the advance of IT. However, there is a problem that a third party would exploit medical information when the information is sent and received through wired or wireless connection. In this paper, a patient information management scheme using group index information for the third party not to illegally exploit a patient's medical information without his consent is proposed. This proposed scheme creates index information in each hierarchical level to be used with access information so that not only medical staff can have access to patient's medical information hierarchically but also it can manage access level in groups. The scheme aims to enable the medical staff to minimize the time spent to analyze the type of disease and to prescribe for it so that they can improve patients' satisfaction. Plus, the scheme aims to improve work efficiency by minimizing the medical staff's workload according to the authority to access patients' medical information.

• Journal of Korea Trade
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• v.27 no.3
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• pp.1-20
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• 2023

Purpose - Using trade data from 2008 to 2019, this study analyzes the impact of trade facilitation on China's agricultural exports under the RCEP framework using a gravity model based on the level of trade facilitation in 13 RCEP countries. Design/methodology - This study constructs a complete set of trade facilitation index systems, comprehensively measures the trade facilitation level of RCEP member countries, and uses a gravity model to verify the critical role of trade facilitation level in enhancing the trade volumes of RCEP member countries. Findings - We found that trade facilitation has a significant impact on China's agricultural exports as a whole. The effect of each primary indicator varies in magnitude, with finance and e-commerce (F) having the most significant impact, followed by customs efficiency (C) and infrastructure development (1); the institutional environment has no significant effect. Originality/value - This study analyzes the impact of trade facilitation on China's agricultural exports from the perspective of exports, and uses the latest data to study the degree of the impact of trade facilitation in importing countries. Measures to jointly enhance trade facilitation among member countries under the RCEP framework are proposed.

• Asian Journal of Innovation and Policy
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• v.12 no.2
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• pp.200-215
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• 2023

The purpose of this paper is to analyze the Korean government's investment priorities for the establishment of a supercomputer joint utilization system using AHP. The AHP model was designed as a two-layered structure consisting of two areas of specialized infrastructure, a one-stop joint utilization system service, and four evaluation items for detailed tasks. For the weight of each evaluation item, a cost efficiency index considering the annual budget was developed for the first time and applied to the weight calculation process. AHP analysis conducted a survey targeting supercomputer experts and derived priorities with 22 data that had completed reliability verification. As a result of the analysis, the government's investment priority was high in the order of dividing infrastructure for each Specialized Center and building resources in stages. In the future, the analysis results will be used to select economic promotion plans and prepare strategies for the establishment of the government's supercomputer joint utilization system.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.10
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• pp.1054-1061
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• 2015

The International Maritime Organization (IMO) has been regulating emissions by making mandatory the compliance with institutions aimed at protecting air quality such as the Energy Efficiency Design Index (EEDI), Ship Energy Efficiency Management Plan (SEEMP) and Tier III. Under the circumstances, one of the response measures considered to be the most feasible is the replacement of existing marine fuel with Liquefied Natural Gas (LNG). The industry has been preemptively building infrastructure and developing and spreading engine technology to enable the use of LNG-fueled ships. The IMO, in turn, recently adopted the International Code of Safety for Ships Using Gases or Other Low-Flash-Point Fuels (IGF Code) as an institutional measure. Thus, it is required to comply with regulations on safety-related design and systems focused on response against potential risk for LNG-fueled ships, in which low-flash-point fuel is handled in the engine room. Especially, the Standards of Training, Certification and Watchkeeping (STCW) Convention was amended accordingly. It has adopted the qualification and training requirements for seafarers who are to provide service aboard ships subject to the IGF Code exemplified by LNG-fueled ships. The expansion in the use of LNG-fueled ships and relevant facilities in fact is expected to increase demand for talents. Thus, the time is ripe to develop methods to set up appropriate STCW training courses for seafarers who board ships subject to the IGF Code. In this study, the STCW Convention and existing STCW training courses applied to seafarers offering service aboard ships subject to the IGF Code are reviewed. The results were reflected to propose ways to design new STCW training courses needed for ships subject to the IGF Code and to identify and improve insufficiencies of the STCW Convention in relation to the IGF Code.

• Journal of Korea Port Economic Association
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• v.32 no.2
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• pp.91-103
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• 2016

The purpose of this study is to analyze the efficiency and productivity of domestic trucking transportation companies using DEA-CCR, BCC, and Malmquist indexes. Here, we analyze the top 14 domestic trucking transportation companies, based on cargo volume. The number of freight agents, trucks, and assets are used as input variables, and cargo volumes and sales are used as output variables. The efficiency of trucking transportation companies is examined using a DEA approach, and Malmquist indexes are applied to analyze productivity. According to the DEA results, the efficiency levels of the CCR, BCC, and scales for three companies (DMU 4, 5, and 10) are 1, indicating that these companies are operated efficiently. At the same time, the Malmquist indexes show that all companies have values smaller than 1, except for the period 2012-2013, indicating that their productivity decreased. Furthermore, the TECI indexes were all larger than 1, except for the period 2012-2013, indicating that the companies are efficient. Lastly, all TCI indexes are smaller than 1, except for the period 2012-2013, indicating regressing trends.

• Journal of the Ergonomics Society of Korea
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• v.33 no.5
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• pp.407-422
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• 2014

Objective: The purpose of the study is to develop quantitative usability evaluation criteria for senior-friendly autonomous transportation robot. Background: The Republic of Korea has become the most rapidly aging society, and is anticipated to enter the post-aged society in 2026. To raise the quality of life of a senior with limited mobility and to reduce the burden of caregivers, many high-tech assistive products with information technologies are developed nowadays. The senior-friendly autonomous transportation robot is one person robot vehicle to move a senior to the destination for hospitals, nursing homes or silver town complex. With built-in navigation system and environmental monitoring censors, it automatically seeks the path to the destination and avoids collision to obstacles and pedestrians on the way. Due to the early stage of the product, few usability studies in this field have been done, mostly on general service robots to assist seniors, power wheelchairs and delivery robots. ISO and KS standards for the service robots are focused on safety. Method: Based on the reference usability index, the early draft of the usability evaluation questionnaires was developed. After small group tests and interviews, the experts modified the initial draft to the Usability Evaluation Criteria for Senior-Friendly Autonomous Transportation Robot (UEC-SFATR). Result: UEC-SFATR consisted of 4 subscales - Safety, Controllability, Efficiency and Satisfaction. All of the 4 subscales of UEC-SFATR were passed the reliability criteria by 4 groups of seniors, divided by gender and familiarity of smart-devices. Conclusion: UEC-SFATR covers wider area of user experiences of the SFATR and is a good measurement tool to help both the users and developers of the robot. Application: This study provides guide to the future product development and product competitiveness evaluation by quantifying user experiences for the SFATR.

• Journal of Korea Spatial Information System Society
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• v.11 no.2
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• pp.133-142
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• 2009

Recently, with the advance of wireless internet and the frequent use of mobile devices, demand for LBS(Location Based Service) is increasing, and research is required on spatial indexes for the storage and maintenance of spatial data to provide efficient LBS in mobile device environments. In addition, the use of flash memory as an auxiliary storage device is increasing in order to store large spatial data in a mobile terminal with small storage space. However, the application of existing spatial indexes to flash-memory lowers index performance due to the frequent updates of nodes. To solve this problem, research is being conducted on flash-memory based spatial indexes, but the efficiency of such spatial indexes is lowered by low utilization of buffer and flash-memory space. Accordingly, in order to solve problems in existing flash-memory based spatial indexes, this paper proposed FR-Tree (Flash-Memory based R-Tree) that uses the node compression technique and the delayed write operation technique. The node compression technique of FR-Tree increased the utilization of flash-memory space by compressing MBR(Minimum Bounding Rectangle) of spatial data using relative coordinates and MBR size. And, the delayed write operation technique reduced the number of write operations in flash memory by storing spatial data in the buffer temporarily and reflecting them in flash memory at once instead of reflecting the insert, update and delete of spatial data in flash-memory for each operation. Especially, the utilization of buffer space was enhanced by preventing the redundant storage of the same spatial data in the buffer. Finally, we perform ed various performance evaluations and proved the superiority of FR-Tree to the existing spatial indexes.

• Journal of the Korean institute of surface engineering
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• v.51 no.4
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• pp.207-213
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• 2018

Not only efficiency of chlorine evolution reaction (CER) but also durability namely service life is very important property in dimensional stable anode for Ballast Water Management System (BWMS) for marine ships. Many researchers have been focused on improving efficiency of CER by controlling composition, phase and surface area for a long time, but the efforts to increase durability was relatively small. In this study, we have investigated the effect of $TiO_2$ protective interlayers on efficiency and durability of DSA electrodes. $TiO_2$ protective interlayers were prepared by thermal oxidation at 500, 600 and $700^{\circ}C$ on Ti substrate. And then the DSA electrodes consisting of $Ti/RuO_2-PdO-TiO_2$ were prepared by thermal decomposition method on $TiO_2$ interlayers. The efficiencies of CER of DSA electrodes without $TiO_2$ interlayer and with $TiO_2$ interlayer grown at 500, 600 and $700^{\circ}C$ were 94.19, 94.45, 84.60 and 76.75% respectively. On the otherhand, durabilities were 30, 55, 90 and 65 hours respectively. In terms of industrial aspect, the performance of DSA is considered high efficiency and durability which can correspond to total production of chlorine. If we considered the performance index of DSA as the product of efficiency and durability, performance indices could be recalculated as 28.26, 50.85, 76.14 and 49.89 respectively. As the thermal oxidation temperature increasing, life time were increased remarkerbly, while efficiency of CER was decreased slightly. As a result, DSA electrode with $TiO_2$ interlayer grown at $600^{\circ}C$ has shown about 2.7 times performace of original DSA electrode without $TiO_2$ interlayer.