• Journal of the Korean Society of Radiology
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• v.15 no.7
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• pp.1041-1047
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• 2021

In this study, the effective dose for frequently general radiography among the diagnostic reference level (DRL) for examinations provided by the government in Korea was evaluated using the Monte Carlo N-Particle eXtended (MCNPX) simulation tool. We were selected to evaluate for a total of 5 examination sites which included head anterior-posterior, chest (posterior-anterior, lateral), abdomen anterior-posterior and pelvis anterior-posterior. Physical conditions such as tube voltage and tube current used in MCNPX simulation were used in domestic conditions of the Korea Disease Control and Prevention Agency (KDCA). To evaluate domestic medical radiation exposure, we used the HDRK-Man computerized human phantom manufactured based on the international standard ICRP 103 that was applied to the MCNPX simulation. The phantom could represent the standard body shape of Koreans. As a results, the effective dose corresponding to the DRL based on adult males of head anterior-posterior position was 0.086 mSv, chest posterior-anterior position was 0.05 mSv, chest lateral was 0.354 mSv, abdomen anterior-posterior position was 0.548 mSv, and pelvis anterior-posterior position was 0.451 mSv.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.2
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• pp.15-29
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• 2021

The signal intersection is the most challenging space for autonomous vehicles. To promote the safe driving of autonomous vehicles on urban roads with traffic signals, autonomous vehicles need to receive traffic signal information from infrastructure through V2I communication. Thus, a protocol for providing traffic signal information was added to the standard traffic signal controller specification of the National Police Agency. On the other hand, there are technical limitations when applying this to digital traffic signal controllers because the protocols are defined mainly for analog traffic signal controllers. Therefore, this study proposes developing a signal information linkage module to provide traffic signal information from a digital traffic signal controller to an autonomous vehicle and an algorithm improvement method that can provide accurate traffic signal information at the time of traffic signal transition.

• Journal of Food Hygiene and Safety
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• v.36 no.1
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• pp.34-41
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• 2021

The purpose of this research is to improve analysis methods of determining the contents of fatty acids in infant formulas and follow-up formulas. A gas chromatography (GC) method was performed on a GC system coupled to flame ionization detector, with a fused silica capillary column (SP2560, 100 m×0.25 mm, 0.20 ㎛). The method was validated using standard reference material (SRM, NIST 1849a). Performance parameters for method validation such as specificity, linearity, limits of detection (LOD) and quantification (LOQ), accuracy and precision were examined. The linearity of standard solution with correlation coefficient was higher than 0.999 in the range of 0.1-5 mg/mL. The LOD and LOQ were 0.01-0.06 mg/mL and 0.03-0.2 mg/mL, respectively. The recovery using standard reference material was confirmed and the precision was found to be between 0.8% and 2.9% relative standard deviation (RSD). Optimized methods were applied in sample analysis to verify the reliability. All the tested products had acceptable contents of fatty acids compared with component specification for nutrition labeling. The result of this research will provide efficient experimental information and strengthen the management of nutrients in infant formula and follow-up formula.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.61-68
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• 2020

In this study, the international standard ISO TS 16774 Part 3 Test Method for Water (wash out) Resistance and KS F 4935 ｢Sealant Injection type for water leakage maintenance of adhesive flexible rubber asphalt series｣, which are standardized as a quality control method of injection type repair materials used for water leakage cracks in underground concrete structures, are currently used in Korea. As a result, considering the performance criteria of "mass change rate -0.1%" stipulated in KS F 4935, the remaining 13 types repair materials, excluding RG-2 of synthetic rubber and UG-1 of urethane, need to be reviewed for stabilization of the loss resistance due to the flow of ground water. The results of this study are determined to be available as a basic indicator for the selection of repair materials used for cracks in concrete structures. In addition, it is expected that the results of this study can be utilized as reference data that can be reflected in the improvement of the quality of repair materials that will be researched and developed later.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.657-666
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• 2022

The International Maritime Organization(IMO) recommends the active implementation of national policies on technological development and energy efficiency to reduce Green House Gas (GHG) in the international shipping sector. Such IMO environmental regulation policies have a great impact on the entire shipping sector and are also a heavy burden on ship's owners. The most reasonable way to curb GHG emissions from ships comes down to the development of zero-emission ships. In other words, the development of a fuel cell ship (FCS) driven by an eco-friendly fuel is an alternative that can escape the IMO regulations. Countries in Asia, Northern America, and Europe independently develop and produce PEMFC, and are pursuing international standardization by acquiring approval in principle from an internationally accredited registration authority. Currently, there are three types of fuel cells (FC) that are recommended for ships: a Polymer Electrolyte Membrane Fuel Cell (PEMFC), a Molten Carbonate Fuel Cell (MCFC), and a Solid Oxide Fuel Cell (SOFC). In this study, PEMFC, which is expected to grow continuously in the global FC market, was analyzed domestic and international development trends, specifications, performance, and empirical cases applied to ships. In addition, when applying PEMFC to ships, it was intended to suggest matters to be considered and the development direction.

• The Korean Journal of Archival Studies
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• no.71
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• pp.237-272
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• 2022

In 2019, the pilot project to establish a record management system for administrative information datasets started in earnest under the leadership of the National Archives. Based on the results of the three-year project by 2021, the improved administrative information dataset management plan will be reflected in public records-related laws and guidelines. Through this, the administrative information dataset becomes the target of full-scale public record management. Although public records have been converted to electronic documents and even the datasets of administrative information systems have been included in full-scale public records management, research on the quality requirements of data itself as raw data constituting records is still lacking. If data quality is not guaranteed, all four properties of records will be threatened in the dataset, which is a structure of data and an aggregate of records. Moreover, if the reliability of the quality of the data of the administrative information system built by reflecting the various needs of the working departments of the institution without considering the standards of the standard records management system is insufficient, the reliability of the public records itself can not be secured. This study is based on the administrative information dataset management plan presented in the "Administrative Information Dataset Recorded Information Service and Utilization Model Study" conducted by the National Archives of Korea in 2021. A study was conducted. By referring to various data, especially public data-related policies and guides, which are being promoted across the government, we would like to derive quality evaluation requirements in terms of records management and present specific indicators. Through this, it is expected that it will be helpful for record management of administrative information dataset which will be in full swing in the future.

• Economic and Environmental Geology
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• v.49 no.6
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• pp.459-467
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• 2016

Due to the limited areal space for installation, borehole heat exchangers (BHEs) at depths deeper than 300 m are considered for geothermal heating and cooling in the urban area. The deep vertical closed-loop BHEs are unconventional due to the depth and the range of the typical installation depth is between 100 and 200 m in Korea. The BHE in the study consists of 50A (outer diameter 50 mm, SDR 11) PE U-tube pipe in a 150 mm diameter borehole with the depth of 300 m. In order to compensate the buoyancy caused by the low density of PE pipe ($0.94{\sim}0.96g/cm^3$) in the borehole filled with ground water, 10 weight band sets (4.6 kg/set) were attached to the bottom of U-tube. A thermal response test (TRT) and fundamental basic surveys on the thermophysical characteristics of the ground were conducted. Ground temperature measures around $15^{\circ}C$ from the surface to 100 m, and the geothermal gradient represents $1.9^{\circ}C/100m$ below 100 m. The TRT was conducted for 48 hours with 17.5 kW heat injection, 28.65 l/min at a circulation fluid flow rate indicates an average temperature difference $8.9^{\circ}C$ between inlet and outlet circulation fluid. The estimated thermophysical parameters are 3.0 W/mk of ground thermal conductivity and 0.104 mk/W of borehole thermal resistance. In the stepwise evaluation of TRT, the ground thermal conductivity was calculated at the standard deviation of 0.16 after the initial 13 hours. The sensitivity analysis on the borehole thermal resistance was also conducted with respect to the PE pipe diameter and the thermal conductivity of backfill material. The borehole thermal resistivity slightly decreased with the increase of the two parameters.

• Journal of Technology Innovation
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• v.26 no.3
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• pp.37-68
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• 2018

Since the 20th century, automobiles, which are the most common means of transportation, have been evolving as the use of electronic control devices and automotive semiconductors increases dramatically. Automotive semiconductors are a key component in automotive electronic control devices and are used to provide stability, efficiency of fuel use, and stability of operation to consumers. For example, automotive semiconductors include engines control, technologies for managing electric motors, transmission control units, hybrid vehicle control, start/stop systems, electronic motor control, automotive radar and LIDAR, smart head lamps, head-up displays, lane keeping systems. As such, semiconductors are being applied to almost all electronic control devices that make up an automobile, and they are creating more effects than simply combining mechanical devices. Since automotive semiconductors have a high data rate basically, a microprocessor unit is being used instead of a micro control unit. For example, semiconductors based on ARM processors are being used in telematics, audio/video multi-medias and navigation. Automotive semiconductors require characteristics such as high reliability, durability and long-term supply, considering the period of use of the automobile for more than 10 years. The reliability of automotive semiconductors is directly linked to the safety of automobiles. The semiconductor industry uses JEDEC and AEC standards to evaluate the reliability of automotive semiconductors. In addition, the life expectancy of the product is estimated at the early stage of development and at the early stage of mass production by using the reliability test method and results that are presented as standard in the automobile industry. However, there are limitations in predicting the failure rate caused by various parameters such as customer's various conditions of use and usage time. To overcome these limitations, much research has been done in academia and industry. Among them, researches using data mining techniques have been carried out in many semiconductor fields, but application and research on automotive semiconductors have not yet been studied. In this regard, this study investigates the relationship between data generated during semiconductor assembly and package test process by using data mining technique, and uses data mining technique suitable for predicting potential failure rate using customer bad data.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.557-575
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• 2005

Much research in core technologies has been done to make it possible the ubiquitous video services over various kinds of user information terminals anytime anywhere in the way the users want to consume. In this paper, we design plototypesystem architecture for the ubiquitous TV program content consumption based on user preference via various kinds of intelligent information terminals in digital home environment, and present an implementation and testing results for the prototype system. For the system design, we utilize the TV Anytime specification fur the consumption of TV program contents based on user preference in TV programs, and also use the MPEG-21 DIA (Digital Item Adaptation) tools which are the representation schema formats in order to describe the context information for user environments, user terminal characteristics, user characteristics for universal access and consumption of the preferred TV program contents. The proposed ubiquitous content mobility prototype system is designed to make it possible to seamlessly consume contents by a single user or multiple users via various kinds of user terminals for the TV program contents they watch together. The proposed ubiquitous content mobility prototype system in digital home environment consists of a home server, a display TV terminal, and an intelligent information terminal. We use 42 TV programs contents in eight different genres from four different TV channels in order to test our prototype system.

• Progress in Medical Physics
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• v.24 no.2
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• pp.119-126
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• 2013

Due to the introduction of CR and DR, it has been neglected the use of the X-ray beam collimator and field size. This study examines nationwide survey of the proper use of collimator and field size by area in a specific field of plain radiography and the current status. Authors emphasized the need for the field size criteria, and propose a standard reference field size in each specific radiologic examination. Total 333 medical institutions (included in Seoul, Gyeonggi-do, Jeolla, Chungcheong, Gangwon-do, Busan area), were investigated in relation to the status of the X-ray beam collimation field size, type specific inspection areas, medical facilities, and image analyses by type to figure out whether they use the adjustment of image field to the specific examination. To assess the awareness and the impact of radiation exposure to the collimation adjustable, 168 radiographers who was working in 10 general hospitals, 10 hospitals, and 10 clinics, were surveyed how they haver adjusted the actual field size. We examine that 61.3% of medical institutions used the "Proper collimation" and only 49.9% of them employed proper one in lumbar spine densely crowded by major organs. 69% among general hospitals, and 65% among hospitals using DR system were using proper collimation. Radiographers recognized that proper adjustment of collimation could reduce the harmful radiation dose on patients. In the survey, 97.6% of respondents were aware of this fact, but only 83.3% of respondents did the adjustment of the size of the collimation field. The using of proper collimation field was low in the nationwide survey, so the effort to reduce the radiation dose on the patients is urgently needed. A unified standard for the field accompanied by thorough education should be needed.