• Journal of KIISE
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• v.43 no.7
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• pp.820-826
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• 2016

There is a growing requirement for big data processing which extracts valuable information from a large amount of data. The Hadoop system employs the MapReduce framework to process big data. However, MapReduce has limitations such as inflexible and slow data processing. To overcome these drawbacks, SQL query processing techniques known as SQL-on-Hadoop were developed. Apache Tajo, one of the SQL-on-Hadoop techniques, was developed by a Korean development group. External merge sort is one of the heavily used algorithms in Tajo for query processing. The performance of external merge sort in Tajo is influenced by two parameters, sort buffer size and fanout. In this paper, we analyzed the performance of external merge sort in Tajo with various sort buffer sizes and fanouts. In addition, we figured out that there are two major causes of differences in the performance of external merge sort: CPU cache misses which increase as the sort buffer size grows; and the number of merge passes determined by fanout.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.4
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• pp.357-367
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• 2005

According to the recent advancement of mobile computing technology and the hardware technology, the mobile device has rapidly come into wide use.'rho data in the central management server needs to confirm to that in mobile devices in order for the mobile device users to access the needed data regardless of time and place. This is called Data Synchronization. Currently, major mobile device manufacturing companies provide the data synchronization solutions, but these solutions are not compatible with other mobile devices/other applied services. In order to solve this problem, OMA(Open Mobile Alliance), mainly composed of mobile telecommunication companies, has suggested using the SyncML(Synchronization Markup Language) data synchronization method. This is an attempt to make a public standard. In this paper, the data synchronization client that synchronizes the PIMS (Personal Information Management System) data in mobile devices like PDA is developed, complying with the SyncML standard requirements.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.2
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• pp.345-366
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• 2018

Article 37 of the International Convention on Civil Aviation requires that rules should be adopted to keep in compliance with international standards and recommended practices established by ICAO. As SARPs are revised annually, each ICAO Member State needs to reflect the new content in its national aviation Acts in a timely manner. In recent years, data-driven international standards have been developed because of the important roles of aviation safety data and information-based legislation in accident prevention based on human factors. The Safety Management System and crew Fatigue Risk Management Systems were reviewed as examples of the result of data-driven rulemaking. The safety management system was adopted in 2013 with the introduction of Annex 19 and Chapter 5 of the relevant manual describes safety data collection and analysis systems. Through analysis of safety data and information, decision makers can make informed data-driven decisions. The Republic of Korea introduced Safety Management System in accordance with Article 58 of the Aviation Safety Act for all airlines, maintenance companies, and airport corporations. To support the SMS, both mandatory reporting and voluntary safety reporting systems need to be in place. Up until now, the standard of administrative penal dispensation for violations of the safety management system has been very weak. Various regulations have been developed and implemented in the United States and Europe for the proper legislation of the safety management system. In the wake of the crash of the Colgan aircraft, the US Aviation Safety Committee recommended the US Federal Aviation Administration to establish a system that can identify and manage pilot fatigue hazards. In 2010, a notice of proposed rulemaking was issued by the Federal Aviation Administration and in 2011, the final rule was passed. The legislation was applied to help differentiate risk based on flight according to factors such as the pilot's duty starting time, the availability of the auxiliary crew, and the class of the rest facility. Numerous amounts data and information were analyzed during the rulemaking process, and reflected in the resultant regulations. A cost-benefit analysis, based on the data of the previous 10 year period, was conducted before the final legislation was reached and it was concluded that the cost benefits are positive. The Republic of Korea also currently has a clause on aviation safety legislation related to crew fatigue risk, where an airline can choose either to conform to the traditional flight time limitation standard or fatigue risk management system. In the United States, specifically for the purpose of data-driven rulemaking, the Airline Rulemaking Committee was formed, and operates in this capacity. Considering the advantageous results of the ARC in the US, and the D4S in Europe, this is a system that should definitely be introduced in Korea as well. A cost-benefit analysis is necessary, and can serve to strengthen the resulting legislation. In order to improve the effectiveness of data-based legislation, it is necessary to have reinforcement of experts and through them prepare a more detailed checklist of relevant variables.

• Journal of the Korean earth science society
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• v.45 no.2
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• pp.157-171
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• 2024

The purposes of this study were: (1) to revalidate the revised Systems Thinking Measuring Instrument (Re_STMI) reported by Lee et al. (2024) among Vietnamese high school students and (2) to investigate the differences in systems thinking abilities between Korean and Vietnamese high school students. To achieve this, data from 234 Vietnamese high school students who responded to translated Re_STMI consisting of 20 items and an Scale consisting of 20 items were used. Validity analysis was conducted through item response analysis (Item Reliability, Item Map, Infit and Outfit MNSQ, DIF between male and female) and exploratory factor analysis (principal axis factor analysis using Promax). Furthermore, structural equation modeling was employed with data from 475 Korean high school students to verify the latent mean analysis. The results were as follows: First, in the item response analysis of the 20 translated Re_STMI items in Vietnamese, the Item Reliability was .97, and the Infit MNSQ ranged from .67 to 1.38. The results from the Item Map and DIF analysis align with previous findings. In the exploratory factor analysis, all items were loaded onto intended sub-factors, with sub-factor reliabilities ranging from .662 to .833 and total reliability at .876. Confirmatory factor analysis for latent mean analysis between Korean and Vietnamese students yielded acceptable model fit indices (χ²/df: 2.830, CFI: .931, TLI: .918, SRMR: .043, RMSEA: .051). Lastly, the latent mean analysis between Korean and Vietnamese students revealed a small effect size in systems analysis, mental models, team learning, and shared vision factors, whereas a medium effect size was observed in personal mastery factors, with Vietnamese high school students showing significantly higher results in systems thinking. This study confirmed the reliability and validity of the Re_STMI items. Furthermore, international comparative studies on systems thinking using Re_STMI translated into Vietnamese, English, and other languages are warranted in the context of students' systems thinking analysis.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.237-241
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• 2010

Many policies have been implemented to mitigate the greenhouse gases in atmosphere overall of sectors. With considering the distinct characteristics of the food security, agricultural sector is no exception to this situation. To this regard, total amount of carbon which is emitted through all of the agricultural production process is calculated, and being based on this result, the demand for the introduction of agricultural production system with low carbon has been rising. Case studies on the application of life cycle assessment (LCA) technique to agricultural sector are found in many countries. For example, life cycle inventory (LCI) data bases of crop, farm infrastructure, fertilizer, farm machinery, and etc., have been constructed and provided by Ecoinvent (Swiss centre for life cycle inventories) of Swiss. In Japan, Top-down typed LCA methodology for agriculture is developed based on the inter-industry analysis, and is evaluated according to the productive method of crop. On the other hand, environmental impact assessment of agricultural system using LCA in Korea is just in the beginning stages. So it is required to assess environmental impact on agricultural fertilizer and pesticide, and to develop their flow modeling, and methodology of LCA of agricultural sector. Environmental impact assessment on agricultural materials, machinery, and infrastructure will also be carried out.

• Spatial Information Research
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• v.19 no.4
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• pp.11-20
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• 2011

In accordance with low carbon and green growth paradigm, a subway is one of major public transit systems for resolving traffic congestion and decreasing traffic accidents. In addition, as subway networks expand, passengers' travel pattern in the subway network change and consequently affect the urban structure. Generally, new subway route has been planned and developed, mainly considering a travel demand forecast. However, it is desired to conduct an empirical analysis on the forecast model regarding change of travel accessibility and passenger demand pattern according to new subway line. Therefore, in this paper, an alternative method, developed based upon a spatial syntax model, is proposed for evaluating new subway route in terms of passenger's mobility and network accessibility. In a case study, we constructed subway network data, mainly targeting the no 9 subway line opened in 2009. With an axial-map analysis, we calculated spatial characteristics to describe topological movement interface. We then analyzed actual modal shift and change on demand of passengers through the number of subway passenger between subway stations and the number of passenger according to comparative bus line from Smart Card to validate suggested methods. Results show that the proposed method provides quantitative means of visualizing passenger flow in subway route planning and of analyzing the time-space characteristics of network. Also, it is expected that the proposed method can be utilized for predicting a passengers' pattern and its impact on public transportation.

• Journal of Korean Library and Information Science Society
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• v.33 no.1
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• pp.291-322
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• 2002

Korean medical libraries have made interlibrary loan active under the korean medical library association since 1969, the sharing acquisition of journals has not been peformed efficiently in the absence of a bibliographic control institute. The medical library of seoul national medical university which is designated to a medical professional information center by korea education academy information developed MEDLIS linking the union catalog and interlibrary loan system and has been operating it in cooperation with the korean medical library association. Two types of questionaries were sent to 350 medical researchers and 160 medical librarians to investigate the realities of domestic and foreign medical information institutes, develop sharing systems and find a solution for sharing systems. Also, some analyses for the recent state of duplicate subscriptions, interlibrary loan, demands for system operations un the basis of the statistics of MEDLIS users were made. The result showed that medical researchers and medical librarians are affirmative for MEDLIS, users need a convenient interlibrary loan system and medical librarians agree to activate interlibrary loan. It also showed that sharing acquisition of journals seemed to be realizable for medical librarians, although there was no intention to improve the centralization of interlibrary loan among them. From the findings, a plan for sharing acquisition of journals established by the sharing acquisition committee under korea medical libraries society and national 8 local centers to play a key role in it was made. Also, a proposal for the establishment of an information center for controlling korean medical bibliographies was suggested. This system will be expected to contribute to make users to acquire materials more effectively and save the national budget.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.4
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• pp.269-276
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• 2012

Salinity distribution in estuary and tidal river is presented by many parameters including tidal forcing, river discharge and geographical effect. Understanding the characteristics of salinity structure is very important in the aspect of water-quality, ecological, and engineering viewpoint. Field measurement was carried out to study the distribution of salinity structure at 2 surface stations at Yeomha channel in the Han River estuary. The results of short- and long-term salinity change according to short and long tidal variability is investigated. For analyzing the axial salinity distribution at Yeomha channel, the salinity data from NFRDI is used in this study. The relationship between freshwater discharge and salinity distribution is represented through the nonlinear regression equation. The empirical equation for salt intrusion length scale, including tide, river discharge, and topographical effect is presented. As the comparison of empirical equation and existing data collected in study area, the characteristic of salt intrusion length and salinity distribution is changed by tide, fresh water, and geographical effect.

• Informatization Policy
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• v.19 no.1
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• pp.74-90
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• 2012

This thesis analyzes the Apple Inc.'s case from the viewpoint of the necessity for the protection of information privacy related to location data as for information society and ubiquitous community. Meanwhile, the regulatory conformity to equilibrium of contradictional value between personal data protection and utilization of information is debated from the fundamental right as for constitutional law concept to the commercial and technological structure in terms of economic and business point. Therefore, this paper reaches the conclusion that the legislative system should form a harmonious relationship between legal protection and lawful utilization to reappraise the present condition of legalization on personal data protection from guaranteeing rights and interests of information subject in the perspective of human rights to information guarantee consequently. As a result, it is required to revaluate the lawfulness of the fine on the violation of administrative duty levied by KCC(Korea Communications Commission).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.72-75
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• 2018

Internet of Things (IOT) technology is rapidly becoming a reality in many parts of our lives through various products and services. Currently, the perception of Internet services for things is becoming common, and the B2C (Business to Consumer) market is explosively increasing as consumers are increasingly willing to purchase Internet devices. In particular, the economic effects of the Internet based smart home sector are known to be very large, and global manufacturers are launching various consumer oriented products based on smart home services.However, current smart home service products are closed systems because they provide independent devices for each manufacturer and provide only specific devices and services linked to them. There is a need for an environment that can provide intelligent smart home service through linkage between objects or services, and a controller that can provide smart control is needed. Therefore, this paper proposes a smart home remote control that can control the Internet devices and services of objects. The proposed smart home remote control provides an environment in which users can directly rescue services through the IFTTT automated service platform, which is an independent platform for each manufacturer.