• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.967-971
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• 2001

The frequency characteristics of the optical pickup are investigated indirectly from the bode diagram of the open loop system and the actuator. However, there is necessity of acquiring the optical pickup bode diagram in a view of the differences in the frequency characteristics. One of the differences is that bode diagrams of the optical pickup are differ to that of the actuator and the other is that bode diagrams of the open loop system include controller, gains and filters. So this paper presents the method acquiring the optical pickup bode diagram. In addition, usefulness of the optical pickup bode diagram was demonstrated by being applied to the optical pickup design. The reason of reducing the development period and acquiring the frequency characteristics of the optical system, the optical pickup bode diagram has many merits in the optical pickup design before acquiring the stable bode diagram of the open loop system.

• Journal of the Korea Safety Management & Science
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• v.18 no.4
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• pp.179-183
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• 2016

The purposes of this research are to modelize test system of SM TESTING by ARENA, software, input several items of specimen's testing process, resources of system and transfer loop, etc, give a hypothesis and then, obtain results reducing the efficiency of the whole system finally by overload of specific facilities in the testing system through the simulation so as to obtain several materials such as specimen and testing facility, transfer loop, etc. by simple and various forms without any necessity of numerical modelization. It will add facilities of over load and reduce facilities with low operation rate, so increase the efficiency of the system.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1446-1452
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• 2009

This study is designed to examine the current status of the performance warranty systems for asphalt pavements implemented in Europe, USA, and Japan, and to review the feasibility and possibility of introducing this system into the Korean environment. For such objectives, the concept and necessity of performance warranty and the status of Korean contracting systems and overseas performance warranty systems were evaluated. In particular, the bidding systems, performance guarantee systems, and maintenance work inclusion status in the projects and warranty specifications of Europe, USA and Japan were comparatively evaluated. And methods of introducing the performance warranty system by utilizing defects liability system and design-build contracts of Korea were suggested.

• Educational Technology International
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• v.24 no.2
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• pp.115-141
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• 2023

The aim of this research is to understand the perceptions of primary and secondary teachers regarding educational resource sharing systems(ERS) by using a qualitative approach. This study conducted Focus Group Interview(FGI) with 20 primary and secondary school teachers. Interview data were analyzed through inductive content analysis method. The results are as follows. First, teachers placed significant emphasis on high-quality, convenient functions, and reward system for sharing resources. Specifically, teachers identified the necessity for a diverse array of materials, systematic categorization of these resources, and the provision of monetary compensation as essential components. Second, the study participants advocated strategies for revitalizing ERS including enhancing accessibility, constructing user-friendly features, increasing awareness, and establishing a reward system to incentivize the resource sharing. In particular, teachers proposed strategies such as developing mobile-based services and AIdriven data recommendation system. These results provide actionable insights for stakeholders engaged in the design, implementation, and evaluation of resource sharing platforms.

• Journal of Auto-vehicle Safety Association
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• v.15 no.4
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• pp.32-38
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• 2023

With the transition from internal combustion engine vehicles to eco-friendly cars, it has become essential to systematically construct an education system for electric vehicles based on high-voltage electric devices. In this study, we discussed the establishment of an educational system for electric vehicles based on high-voltage electric devices and proposed methods for qualifications after completing the education. To ensure systematic education, we presented a classification of learners according to their levels and job competencies. Additionally, we emphasized the importance of providing adequate practical training equipment for courses that require higher qualifications. Finally, to distinguish between the levels of completion of training and practical skills, we highlighted the necessity of implementing a system to certificates to individuals who have successfully completed the systematic training program.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.12
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• pp.654-662
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• 2017

When emergency core cooling system (ECCS) is operated during loss of coolant accident (LOCA) in a pressurized water reactor (PWR), pressurized thermal shock (PTS) phenomenon can occur as cooling water is injected into a cold leg, mixed with hot primary coolant, and then entrained into a reactor vessel. Insufficient flow mixing may cause temperature stratification and steam condensation. In addition, flow vibration may cause thermal stresses in surrounding structures. This will reduce the life of the reactor vessel. Due to the importance of PTS phenomenon, in this study, calculation was performed for Test 1 among six types of OECD/NEA ROSA tests with ANSYS CFX R.17. Predicted results were then compared to measured data. Additionally, because temperature difference between the hot coolant at the inlet of the cold leg and the cold cooling water at the inlet of the ECCS injection line is 200 K or more, buoyancy force due to density difference might have significant effect on thermal-hydraulic characteristics of flow. Therefore, in this study, the necessity to include buoyancy force term in governing equations for accurate prediction of single phase thermal stratification in both cold legs and downcomer by ECCS injection was numerically studied.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.257-263
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• 2013

In case of image observation equipments, CCTV for short distance visual field is usually installed and operated mostly as the means of crime-prevention. However, the extensive demand for monitoring problems in case of the increase in intelligent crimes and disasters has led to the necessity of the development of long-distance observation equipments embedded with Night View functions. In case of the Night View equipments, the relevant market is set up to be focused mostly on Thermal Observation Device(hereinafter, TOD), but some shortcomings such as the limitation of image visibility and excessive maintenance cost, etc. have actually caused the necessity of new long distance Night View equipment. Moreover there might follow lots of difficulties in long-distance visualization in the event that irregular reflection is generated by minute particles in the atmosphere such as fog, smog, and dust, etc. These factors are motivate the work presented in this study. Our study is aimed at the realization of Pulsed Laser Illuminator and newly proposed Range-Gated image acquisition technology. And also the implementation of Tracker for continuous trace of the objects of interest from the obtained sequence images.

• The Korean Journal of Archival Studies
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• no.58
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• pp.95-145
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• 2018

As a communication language, non-text records and archives such as photographs, images, and videos are becoming more important than text records. As a result, domestic institution, organizations, and specialists related to record management have been emphasizing the necessity of the archive management system appropriate for the distinctive characteristics of image records. This paper summarizes the points to be considered for the establishment of the Korean audiovisual archives management system, based on the writer's experience of participating in the International Audiovisual Archives Management Training for professionals in the world(INA Frame) of 2018. In particular, various types of contents including cinema, broadcasting, cultural should be managed at the national level. Furthermore, the necessity of a new concept establishment for "public audiovisual heritage" is accentuated. In addition, the tasks regarding the establishment of foundation, such as the modification of the related systems and infrastructures, and the layouts of the institution or governance, should be reviewed and revised. Moreover, the preliminary tasks revised, should be lead to the establishment of stable management system for public audiovisual archives of Korea.

• Journal of radiological science and technology
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• v.41 no.6
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• pp.617-626
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• 2018

This study aims to provide the basic data helpful for the improvement of rights and interests of radiological technologists, by understanding the current working environment and if they get the proper reward through the analysis on the perception of appropriateness of current wage and job satisfaction of radiological technologists. Survey was conducted to evaluate the perception of satisfaction with job and wage system, work intensity, necessity of the radiological technologist limit system, and turnover in accordance. The appropriate starting salary was low in case of women and non-capital area, and when the age, academic background, career, and hospital size were lower. The appropriate wage was low in case of women and non-capital area, and when the academic background and hospital size were lower. The negative perception of the necessity to change the wage system was shown in university hospitals. Regarding the work intensity, in case of women and low career, and when the age, academic background, and hospital size were higher, the work intensity was perceived as high. When the academic degree and hospital size were lower, the positive perception of the radiological technologist limit was shown. The turnover intention was high in case of women, and when the age, academic background, career, and hospital size were lower. In order to increase the job satisfaction of radiological technologists, it would be necessary to the appropriate reward and the environment where they could concentrate on work.

• Journal of The Korean Society of Clinical Toxicology
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• v.4 no.1
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• pp.32-43
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• 2006

Purpose: Toxic Exposure Surveillance System (TESS) is widely used for poisoning data collection and making a counterplan. But, there were few reports about poisoning data collection using TESS in Korea. The aim was to collect poisoning data using TESS report form and investigate the recognition of emergency physician about the necessity of TESS as preliminary survey. Methods: Retrospectively, we gathered data from hospital records about the patient who admitted hospital emergency room due to poisoning. Date were gathered by paper and/or web client system report form in patients recruited by ICD-10 codes Results: From Jun 2004 to May 2005,3,203 patients were enrolled in 30 hospitals and their mean age was $44.9{\pm}20.3years$ old(male: female = 1,565: 1,638). The most frequent site of exposure was their own residence (73.2%, 2,345/3,203) and most of reported patients were older than 20 years(89.7%, 2,871/3,203). Frequent substances involved in poisoning were medication(41.9%) and pesticide(33.3%). Intentional poisoning was 60.7%(1,954). In fatality, overall frequency was 5.1%(162/3,203) and the most frequent route of exposure was ingestion(96.3%, 156/162) and the most frequent substance was pesticide(85.2%, 138/ 162). Antidotes were administered in 202 patients(2-PAM, atropine, antivenin, N-acetylcystein, vitamin K, flumazenil, ethanol, methylene blue, naloxone, calcium compound). 19 of 20 emergency physicians agreed with necessity of TESS. Conclusion: Data collection using TESS report form showed preliminary poisoning events in Korea. Frequent poisoning substance were medication and pesticide. The fatality was mainly related with pesticide ingestion. Many doctors in emergency room recognized the necessity of TESS.