• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.585-591
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• 2017

Turbocharging is widely used in diesel and gasoline engines as an effective way to reduce fuel consumption. But turbochargers have turbo-lag due to mechanical friction losses. Bearing friction losses are a major cause of mechanical friction losses and are particularly intensified in the lower speed range of the engine. Current turbochargers mostly use oil bearings (two journal bearings and one thrust bearing). In this study, we focus on the bearing friction in the lower speed range. Experimental equipment was made using a drive motor, load cell, magnetic coupling, and oil control system. We measured the friction losses of the turbocharger while considering the influence of the rotation speed, oil temperature, and pressure. The friction power losses increased exponentially when the turbocharger speed increased.

• Strategy21
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• s.43
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• pp.5-28
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• 2018

The tensions between the U.S and China, which form the two pillars of the G2 era, seem to have persisted even after the Trump administration inaugurated. The strong confrontation between the two in recent foreign security issues may drive to develop an inadvertent military conflict, and it is high likely to occur in the maritime are. The purpose of this study is not only to analyze the balance of modernized naval forces in the PLAN through naval strategy changes and weapons system modernization trend, but also to predict the impact of the geographical proximity difference on the balance of naval forces in the disputed areas. It examined the impact of distance and geography on naval power by assessing the modernization pattern of the PLAN and capabilities in the context of two scenarios at different distances from China by 2020: one centered on Taiwan and the other on the Spratly Islands. The PLAN's strategy had impact on operational concept and forces construction. First, from the viewpoint of operation operational concept, it can be seen that the passive defense is changing into active defense. Second, in terms of power construction, it can threaten the surface and submarines of U.S power from a distance. And they generated follow three features; The ocean is not the focus of Chinese submarines, Horizontal and vertical expansion of Chinese naval vessels, The improvement of the suppression ability as the Chinese naval modernization ratio increases. The strength of the PLAN is dominant over the U.S in terms of reserves, and it can complement the qualitative deterioration by utilizing nearby bases in the vicinity of the mainland, such as the Taiwan Strait. However, due to the shortage of aircraft carriers, there is a possibility that it will take some time to secure the advantage of air and ocean in the amphibious operation. Therefore, as the dispute is prolonged, China may fail to achieve its original goal. In addition, the lack of cutting edge Commanding Ships may bring to weaken the C2 capabilities. At results, it is expected that PLAN will not be able to have a superiority in the short term due to lagging behind U.S advanced technology. Nevertheless, PLAN has strengthened its naval power through modernization sufficiently and it is highly likely to use force. Especially, it is more likely in the region where the naval power operation like the Taiwan Strait is possible with the almost equality to that of the United States. China will continue to use its naval forces to achieve a rapid and decisive victory over U.S in the close area from the land.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.186-195
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• 2017

Recently, autonomous vehicles have been studied actively. There are various technologies such as ITS, Connected Car, V2X and ADAS in order to realize such autonomous driving. Among these technologies, it is particularly important to recognize where the vehicle is on the road in order to change the lane and drive to the destination. Generally, it is done through GPS and camera image processing. However, there are limitations on the reliability of the positioning due to shaded areas such as tunnels in the case of GPS, and there are limitations in recognition and positioning according to the state of the road lane and the surrounding environment when performing the camera image processing. In this paper, we propose that LED lights should be installed for autonomous vehicles in tunnels which are shaded area of the GPS. In this paper, we show that it is possible to measure the position of the current lane of the autonomous vehicle by analyzing the color temperature after constructing the tunnel LED lighting simulation environment which illuminates light of different color temperature by lane. Based on the above, this paper proposes a lane positioning technique using tunnel LED lights.

• Journal of Korea Game Society
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• v.15 no.5
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• pp.57-78
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• 2015

This Study is the effect of the inclusive institution on a nation's economic development. Therefore, we focused on the gaming industry as an index that can drive the economic growth in the future. The reason to compare the game institution in South Korea and Germany is that both countries began to develop the game by the State, but the game institution in South Korea and Germany at the present time are sharply opposed, because the institutions can focus on the main points that are experiencing this difference. The results of this study, first, open/closed network in institutionalized aspect affects the social status of the game. This second, game workers in the legal institution has been classified as artists in Germany, as addicts in South Korea. And, Germany also has incentives to creators protected profits reinvested in the gaming industry, Korea leads to punitive exploitation is being transferred to the group for addiction treatment that revenue. Third, this exclusive and inclusive institutional system could affect the stable growth of the game market. As a result, South Korea's state institutions will notice that you get a result away from opportunities for economic development due to the loss of inclusiveness.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1105-1111
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• 2010

The Korea Atomic Energy Research Institutes has been developing the SMART (System integrated Modular Advanced ReacTor), an environment-friendly nuclear reactor for the generation of electricity and to perform desalination. SMART reactors can be exposed to various external and internal loads caused by seismic and coolant flows. The CRDM(control rod drive mechanism), one of structures of the SMART, is a component which is adjusting inserting amount of a control rod, controlling output of reactor power and in an emergency situation, inserting a control rod to stop the reactor. The purpose of this research is performing the analysis of dynamic characteristic to ensure safety and integrity of structure of CRDM. This paper presents two FE-models, 3-D solid model and simplified Beam model of the CRDM in the coolant, and then compared the results of the dynamic characteristic about the two FE-models using a commercial Finite Element tool, ABAQUS CAE V6.8 and ANSYS V12. Beam 4 and beam 188 of simplified-model were also compared each other. And simplified model is updated for accuracy compare to 3-D solid.

• Journal of Korean Home Economics Education Association
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• v.25 no.3
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• pp.61-77
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• 2013

Developing textbook evaluation criterion is as important as textbook development in education. Home economics subject has been involved in textbook evaluation since 1995, at which the first home economics textbook was under the national authorization system in South Korea. There has been little research on home economics textbook evaluation criterion even though there were more studies using textbook analysis. The purposes of this study were to explore the reason why subject perspectives were reflected on the textbook evaluation criterion, the relationships between the perspectives presented by national curriculum and technology home economics textbook evaluation criterion, and the future direction for developing textbook evaluation criterion. So this study was related to analyze practical arts(technology home economics) textbook evaluation criterion and the meaning of subject perspectives in textbook evaluation criterion, to drive perspectives consistently presented by the 2007 revised and 2011 revised national curriculum, to analyze the relationships between the perspectives in national curriculum and textbook evaluation criterion, and to provide the future direction for textbook evaluation criterion development. Textbook evaluation criterion is very important because it provides subject perspectives for developing textbook, delivers the core concepts and unique values of our subject, and provides the direction for teacher education. According to the analysis of both national curriculum, the perspectives such as management competency, life competency, practical experience, integrative competency for understanding individual and family, career and life planning, and life problem-solving were presented in this study. Implication for future research would be needed to develop the factors of textbook evaluation criterion based on the perspective presented by national curriculum.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.535-545
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• 2019

The PBA of ship weapon system should be installed and operated under harsh environmental conditions and so it should be highly reliable to endure the mission profiles during its entire lifetime. In the case of PBA failure during operation, rapid maintenance is highly likely to be difficult due to problems such as supply of parts, which can have a devastating effect on the mission. In order to validate the reliability of PBA, a series of tests are performed with PBA samples, but they require time, testing facilities, samples, expenses and failure analysis if failed. The reliability of PBA is predicted on the basis of specifications such as MIL-HDBK-217F, but this specification does not take into account failure mechanisms for specific design details, environment and usage, interconnects and its characteristics that drive many failures of PBA in the field. Therefore, this study predicts the reliability of PBA using an RPA tool and proposes the RPA methodology as a validation process at the design stage. With RPA, it is now possible to achieve design validation including inherent failure mechanism, identification of weakest link, alternative design options, and test plan development.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.240-240
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• 2011

The first neutral beam injector (NBI-1) has been developed for the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak. A first long pulse ion source (LPIS-1) has been installed on the NBI-1 for an auxiliary heating and current drive of KSTAR core plasmas. Performance of ion and neutral beam extractions in the LPIS-1 was investigated initially on the KSTAR NBI-1 system, prior to the neutral beam injection into the main plasmas. The ion source consists of a JAEA magnetic bucket plasma generator with multi-pole cusp fields and a set of KAERI prototype-III tetrode accelerators with circular apertures. The inner volume of plasma generator and accelerator column in the LPIS-1 is approximately 123 liters. Final design requirements for the ion source were a 120 kV/ 65 A deuterium beam and a 300 s pulse length. The extraction of ion beams was initiated by the formation of arc plasmas in the LPIS-1, called as an arc-beam extraction method. A stable ion beam extraction of LPIS-1 has been achieved up to an 100 kV/42 A for a 4 s pulse length and an 80 kV/25 A for a 14 s pulse length. Optimum beam perveance of 1.21 microperv has been found at an accelerating voltage of 80 kV. Neutralization efficiency has been measured by using a water flow calorimetry (WFC) method of calorimeter and an operation of bending magnet. The full-energy species of ion beams have been detected by using the diagnostic method of optical multichannel analyzer (OMA). An arc efficiency of the LPIS was 0.6~1.1 A/kW depending on the operating conditions of arc discharge.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.222-232
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• 2004

The sample collection room(SCR) will have much more influence than all the other departments for the improvement of hospital image, if anyone coming to the SCR in the hospital goes back with the perfect complacency and because most clients who have much stresses and fatigues pay a final visit to the SCR via receipt-diagnosis- acceptance process. SCR has improved its image for the purpose of gratifying clients, in order for clients to visit the hospital again, the quality improvement(QI) team in the Diagnosis Inspection Medical Department has come to a conclusion as follows. The degree of client gratification before improvement marks 65.9 point, but the degree after improvement was 74.2 point. Therefore, satisfaction has increased by 8.3 points. The degree of client gratification in groups before improvement marks (1) service parts-89.2 points (2) facilities and environments-49.1 point (3) toilet facilities-46.3 point. But its gratification after improvement marks (1) 92.5 point (2) 60.1 point (3) 61.0 point. Therefore the degree of satisfaction has increased by (1) 3.3 point, (2) 11.0 point, (3) 14.7 point. The progress of facility improvement plans and the exclusion of improvement on the facility contents in the hospital have made facilities and environments of SCR and toilet facilities to be poorly improved. Although service parts have a good mark, and the facilities and environments are not scoring well, the whole degree clients' gratification of SCR couldn't be helped by the low grade. Therefore the bottom line for the clients' gratification of SCR in the future is to ameliorate the facilities and environments. SCR will take the clients' gratification survey every year and if any items get low marks, that is, below 90 point throughout the survey, SCR will immediately starts the improvement work for the clients' gratification with operating the programs of controlling quality continually, and SCR should induce the operation of services, participating in the kind campaign drive for clients. So SCR will adopt the incentive system for the best staff members who perform these kinds of services.

• Imaging Science in Dentistry
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• v.38 no.3
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• pp.169-176
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• 2008

Purpose : To assess the diagnostic accuracy and value in an imaging technique field through the comparison of cone beam computed tomography and conventional panoramic radiography in assessing the topographic relationship between the mandibular canal and impacted third molars. Materials and Methods : Participants consisted of 100 patients offered the images through cone beam computed tomography and panoramic radiography. PSR-$9000^{TM}$ Dental CT system (Asahi Roentgen Ind. Co., Ltd, Japan) was used as the unit of cone beam computed tomography. CE-II (Asahi Roentgen Ind. Co., Ltd, Japan) and Pro Max (Planmeca Oy, Finland) were used as the unit of panoramic radiography. The images obtained through panoramic radiography were classified into 3 types according to the distance between mandibular canal and root of mandibular third molar. And they were classified into 4 types according to the proximity of radiographic feature. The images obtained through cone beam computed tomography based on the classification above were classified into 4 types according to the location between the mandibular canal and the root and were analyzed. And they were classified into buccal, inferior, lingual, and between roots, according to the location between mandibular canal and root. The data were statistically analyzed and estimated by $X^2$-test. Results : 1. There was no statistical significance according to 3 types (type I, type II, type III) through CBCT. 2. The results of 4 types (type A, type B, type C, type D) through CBCT were as high prevalence of CBCT 1 in type A, CBCT 2 in type B, CBCT 3 in type C, and CBCT1 in type D and those of which showed statistical significance (P value=0.03). 3. The results according to location between mandibular canal and root through CBCT recorded each 49, 25, 17, 9 as buccal, inferior, lingual, between roots. Conclusion : When estimating the mandibular canal and the roots through the panoramic radiography, it could be difficult to drive the views of which this estimation was considerable. Thus it is required to have an accurate diagnostic approaching through CBCT that could estimate the location between mandibular canal and roots.