• Journal of Soil and Groundwater Environment
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• v.18 no.5
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• pp.26-38
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• 2013

In this study, priority for groundwater contamination management was assessed based on regional vulnerability in Goyang-si area, Gyonggi-do, Korea using analytic hierarchy process (AHP) and geographic information system (GIS). We proposed a concept for regional vulnerability to groundwater contamination with using socio-environmental vulnerability factors, which can be classified into three properties including regional hydrogeological property, contamination property, and groundwater use property. This concept is applied to Goyang-si area. For AHP analysis, an expertise-targeted survey was conducted. Based on the survey, a total of 10 factors (criteria) and corresponding weights for regional vulnerability assessment were determined. The result shows that regional contamination property is the most weighted factor among the three property groups (hydrogeological property: contamination property: groundwater use property = 0.3: 0.4: 0.3). Then, database layers for those factors were constructed, and regional vulnerability to groundwater contamination was assessed by weighted superposition using GIS. Results show that estimated regional vulnerability score is ranged from 22.7 to 94.5. Central and western areas of Goyang-si which have groundwater tables at shallow depths and are mainly occupied by industrial and residential areas are estimated to be relatively highly vulnerable to groundwater contamination. Based on assessed regional vulnerability, we classified areas into 4 categories. Category 1 areas, which are ranked at the top 25% of vulnerability score, take about 2.8% area in Goyang-si and give a high priority for groundwater contamination management. The results can provide useful information when the groundwater management authority decide which areas should be inspected with a high priority for efficient contamination management.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.72-74
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• 2012

위성의 상태를 모니터링하고 임무수행 준비 및 결과를 분석하기 위해 위성에서는 주기적으로 텔레메트리 프레임을 생성하여 지상으로 전송한다. 텔레메트리 프레임을 통해 많은 데이터가 전송될수록 정확한 위성의 상태 분석이 가능하고 위성 운용을 용이하게 할 수 있다. 그러나 위성에서 지상으로 전송할 수 있는 텔레메트리의 전송속도는 하드웨어의 성능에 따라 제한되며, 특히 저궤도 위성의 경우에는 지상과 교신이 가능한 시간이 짧다는 제약으로 인해 한정된 시간 안에 정해진 전송속도로 보낼 수 있는 데이터의 양에는 한계가 있다. 이러한 제약조건 하에서 최대한 많은 정보를 효율적으로 전송할 수 있도록 위성의 텔레메트리를 생성할 때 비트 정보들을 모아 하나의 바이트로 묶어서 텔레메트리 크기를 최소화하는 방법을 이용한다. 위성비행소프트웨어는 태스크 스케쥴링, 열제어, 전력제어, 자세제어, 원격명령처리, 원격측정데이터 처리 등의 기능별로 모듈화 되어있다. 각 모듈마다 텔레메트리로 전송되는 데이터들이 존재하고 비트 정보들을 모으는 기능도 해당하는 모듈에서 각각 담당한다. 따라서 각 모듈들이 독립적이지 못하고 텔레메트리 처리를 담당하는 모듈과 다른 모듈들 간의 커플링(coupling)이 존재하게 되어 하나의 텔레메트리 데이터 변경이 여러 모듈에 영향을 미치게 된다. 본 논문에서는 모듈들 간의 커플링을 최소화하고 텔레메트리의 변경사항이 위성비행소프트웨어 코드 자체에는 영향을 주지 않도록 하기위한 데이터베이스 테이블을 이용한 텔레메트리 처리 방안에 대하여 설명한다.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.49.3-50
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• 2018

Korea has kept its records of astronomical phenomena since around 2,000 years ago. However, the contents and scope of relevant service have been limited for researchers who need those records due to lack of complete data collection. In this regard, it is necessary to establish efficient collection and management systems of Korean astronomical records by utilizing an environment that is easily accessible. This study is intended to complete the development of a testbed system that allows researchers to systematically input and validate, in a Web environment, multiple astronomical records among the historical documents until Modern Joseon after the Three Kingdoms Period. Recognition of the pre-translated data and tables in advance is followed by its storage in the database built on the Web. Then, data validation is implemented by providing a retrieval service according to a specific form to only a finite number of researchers who have access authority. This study is targeted at a testbed system that takes around three months to be completely developed. The completed testbed system is expected to allow internal and external researchers of an organization to easily access the service on the Web. This will ensure that the accuracy of the data can be verified mutually and help identify areas of service improvement. The opinions collected regarding service improvement will be reflected in the future system. Eventually, domestic astronomical records will subsequently be able to be utilized internationally through the multilingual service.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.12
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• pp.429-436
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• 2022

Temporary files are generated when the Hash Join is performed on tables larger than the memory. During the join process, each temporary file is deleted sequentially after it completes the I/O operations. This paper reveals for that the fallocate system call and file deletion-related trim options significantly impact the hash join performance when temporary files are managed on SSDs rather than hard disks. The experiment was conducted on various commercial and research SSDs using PostgreSQL, a representative open-source database. We find that it is possible to improve the join performance up to 3 to 5 times compared to the default combination depending on whether fallocate and trim options are used for temporary files. In addition, we investigate the write amplification and trim command overhead in the SSD according to the combination of the two options for temporary files.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.831-842
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• 2021

Accurate measurements of feed energy values have a positive effect on the control of feed intake for animals, the formation of prices, and on economic profits. However, few studies have attempted to measure the energy values of domestic roughages and to validate an energy value prediction model. The purpose of this study is to build a database through measurements of the nutrient digestibility and digestible energy results of roughages used in Korea and to evaluate the domestic applicability of the National Research Council (NRC) estimation model. Oat hay, annual ryegrass, tall fescue, barnyard millet, and concentrates for beef cattle were used in the test. As a result of an in vivo digestibility trial, the total digestible nutrients (TDN) of oat hay, annual ryegrass, tall fescue, and barnyard millet were found to be 68.73, 55.02, 55.71, and 52.89%, respectively. As a result of comparing the estimated values using the NRC equation with the in vivo results, there was a difference of 3.55 to 6.84%P in the TDN. Inferred from this result, it is considered that TDN calculations using the NRC equation can be reasonable for the test feeds used in this study. These results can be utilized when revising the Korean Standard Tables of Feed Composition, which provides a comprehensive overview of Korean feed.

• The Journal of the Korea Contents Association
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• v.15 no.9
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• pp.403-410
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• 2015

Since 1970, MRI has greatly been developing in terms of strength of magnetic field, the number of receipt channels, and short time of examination. With the development of digital systems and wireless network, hospitals have also acquired, saved, and managed digital images taken by various kinds of medical imaging equipment. However, domestic universities fail to provide practice training course independently thanks to expensive practice equipment and high maintenance cost, and rely on clinical training. Therefore, this study developed a MR patient diagnosis program based on Windows PC to help out students before their working in clinical filed. The designed Relational Database of MRI Simulator is made up of seven tables according to functions and data characteristics. Regarding the designed patient information, each stepwise function was classified by the patient registration method in clinical field. In addition, on the assumption of the basic information for diagnosis, each setting and content were classified. The menu by execution step was arrayed on the left side for easy view. For patient registration, a patient's name, gender, unique ID, birth date, weight, and other types of basic information were entered, and the patient's posture and diagnosis direction were set up. In addition, the body regions for diagnosis and Pulse Sequence were listed for selection. Also, Protocol name and other additional factors were allowed to be entered. The final window was designed to check diagnosis images, patient information, and diagnosis conditions. By learning how to enter patient information and change diagnosis conditions in this program, users will be able to understand more theories and terms learned in practice and thereby to shorten their learning time in actual clinical work.

• KSCI Review
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• v.14 no.2
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• pp.185-197
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• 2006

A star schema consists of a central fact table, which is surrounded by one or more dimension tables. Each row int the fact table contains a multi-part primary key(or a composite foreign key) along with one or more columns containing various facts about the data stored in the row Each of the composit foreign key components is related to a dimensional table. The combination of keys in the fact table creates a composite foreign key that is unique to the fact table record. The composite foreign key, however, is rarely unique to the fact table record in real-world applications, particularly in financial applications. In order to make the composite foreign key be the determinant in real-world application, some precalculation might be performed in the SQL relational database, and cached in the OLAP database. However, there are many drawbacks to this approach. In some cases, this approach might give users the wrong results. In this paper, an approach to fact table modeling and related MDX query composing, which can be used in real-world applications without performing any precalculation and gives users the correct results, is proposed.

• Journal of Nutrition and Health
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• v.40 no.sup
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• pp.9-21
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• 2007

This study aimed to assess the total sugar intake for Korean and to identify major food sources contributing to those food components. Korean adults aged over 20 years old from the Korean National Health and Nutrition Examination Survey (KNHANES) 2001 and 2002 were selected. The data were analyzed to obtain nationally and seasonally representative information on the health and nutritional status of the Korean. Forty food groups were used in identifying food sources of total sugar and energy intake. Total sugar contents of foods in the KNHANES data sets were estimated by food code matching technique with Release 18 of the USDA National Nutrient Database for Standard Reference. Sample weighted means, standard errors, and population percentages were calculated using SAS and SUDAAN. The mean total sugar intake of the Korean was 60.3g in 2001, 40.9g in spring 2002, 45.7g in summer 2002, and 52.1g in fall 2002, which were 30-44% of intake of US people. Fresh fruit was identified as the most significant food source for total sugar intake in Korean population in all age groups and all seasons. The next major food sources following fresh fruits were candy/jelly/syrup/honey, coffee/coffee caream, vegetables, Kimchi, soft drinks, milk, fruit juice, cookie/cracker/cake, and vegetable juice/grain juice, which showed similar results through the seasons. While carbonated soft drink was the most significant food sources for total sugar or added sugar intakes for US people. The total sugar intakes were significantly higher in women, higher educational level, and residing in metropolitan area. As intake of total sugar increased, intakes of protein, fiber, calcium, phosphorus, iron, Vit A, B1, B2, C, niacin showed significantly increased, while high intakes of added sugars showed low intakes of some micronutrients in the US people. Percentages of people who consumed nutrients below EAR were less in higher total sugar intake group than in lower intake group. From these results, we can conclude that the food consumption habits including the total sugar intake of Korean people seems relatively good so far. More reliable database of total sugar and added sugar composition tables in public domain should be established in the future, and also more researches about total sugar and added sugar for Koreans should be continued.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.177-188
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• 2007

A star schema consists of a central fact table, which is surrounded by one or more dimension tables. Each row in the fact table contains a multi-part primary key(or a composite foreign key) along with one or more columns containing various facts about the data stored in the row. Each of the composit foreign key components is related to a dimensional table. The combination of keys in the fact table creates a composite foreign key that is unique to the fact table record. The composite foreign key, however, is rarely unique to the fact table retold in real-world applications, particularly in financial applications. In order to make the composite foreign key be the determinant in real-world application, some precalculation might be performed in the SQL relational database, and cached in the OLAP database. However, there are many drawbacks to this approach. In some cases, this approach might give users the wrong results. In this paper, an approach to fact table modeling and related MDX query composing, which can be used in real-world applications without performing any precalculation and gives users the correct results, is proposed.

• Journal of the Korea Society of Computer and Information
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• v.24 no.11
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• pp.127-133
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• 2019

SQL is the most common language in data processing. Therefore, most of the colleges offer SQL in their curriculum. In this research, an auto scoring SQL test is proposed for the efficient results of SQL education. The system was treated with algorithms instead of using expensive DBMS(Data Base Management System) for automatic scoring, and satisfactory results were produced. For this system, the test question bank was established out of 'personnel management' and 'academic management'. It provides users with different sets of test each time. Scoring was done by dividing tables into two sections. The one that does not change the table(select) and the other that actually changes the table(update, insert, delete). In the case of a search, the answer and response were executed at first and then the results were compared and processed, the user's answers are evaluated by comparing the table with the correct answer. Modification, insertion, and deletion of table actually changes the data table, so data was restored by using ROLLBACK command. This system was implemented and tested 772 times on the 88 students in Computer Information Division of our college. The results of the implementation show that the average scoring time for a test consisting of 10 questions is 0.052 seconds, and the performance of this system is distinguished considering that multiple responses cannot be processed at the same time by a human grader, we want to develop a problem system that takes into account the difficulty of the problem into account near future.