• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.138-147
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• 2005

This paper presents a SPMSM(Surface-mounted Permanent Magnet Synchronous Motor) servo drive system using high performance TMS320F2812 DSP for the industrial application. The DSP(Digital Signal Processor) Controller enables an enhanced real time algorithm and cost-effective design intelligent for only exclusively motor drives which can be yield enhanced operation, fewer system components, lower control system cost, increased efficiency and high performance. The suggested system contain speed and current sensing circuits, SVPWM(Space Vector Pulse Width Modulation) and I/O interface circuit. The developed servo drive control system showns a good response characteristics results and high performance features in general purposed 400[w] machine. This system can achieve cost reduction and size minimization of controllers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.510-511
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• 2017

In this paper, we have studied to minimize the lifetime and fault occurrence of LED fixtures, which have a short lifetime and frequent faults. In the current LED chip, the lifetime is semi-permanent, but compared to the lifetime of the LED chip, Drivers do not last long. In recent years, low-priced LED illuminators such as those from China have entered the market, and many consumers are perceiving LED illuminators. In order to solve these problems, we designed an LED illuminator of 25W class by using AC Direct IC, which has a longer lifetime than the conventional driver, by removing the electrolytic capacitor in the LED driving driver which is the cause of the failure.

• Progress in Superconductivity
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• v.14 no.1
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• pp.39-44
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• 2012

The fabrications condition and superconducting properties of top-seeded melt growth (TSMG) processed $GdBa_2Cu_3O_{7-y}$ (Gd123) bulk superconductors were studied. Processing parameters (a maximum temperature ($T_{max}$), a temperature for crystal growth ($T_G$) and a cooling rate ($R_G$) through a peritectic temperature ($T_P$) for the fabrication of single grain Gd123 superconductors were optimized. The magnetic levitation forces, trapped magnetic fields, superconducting transition temperature ($T_c$) and critical current density ($J_c$) of the Gd123 bulks superconductors were estimated. Single grain Gd123 bulk superconductors were successfully fabricated at the optimized processing condition. The $T_c$ of a TSMG processed Gd123 sample was 92.5 K and the $J_c$ at 77 K and 0 T was approximately $50kA/cm^2$. The trapped magnetic field contour and magnetic levitation forces were dependent on the top surface morphology of TSMG processed Gd123 samples. The single grain Gd123 samples, field-cooled at 77 K using a Nd-B-Fe permanent magnet with 5.27 kG and 30 mm dia., showed the trapped magnetic field contour of a single grain with a maximum of 4 kG at the sample center. The maximum magnetic levitation forces of the single grain Gd123 sample, field-cooled or zero field-cooled, were 40 N and 107 N, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.180-180
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• 2000

Plasma source ion implantation is a new doping technique for the formation of shallow junction with the merits of high dose rate, low-cost and minimal wafer charging damage. In plasma source ion implantation process, the wafer is placed directly in the plasma of the appropriate dopant ions. Negative pulse bias is applied to the wafer, causing the dopant ions to be accelerated toward the wafer and implanted below the surface. In this work, inductively couples plasma was generated by anodized Al antenna that was located inside the vacuum chamber. The outside wall of Al chamber was surrounded by Nd-Fe-B permanent magnets to confine the plasma and to enhance the uniformity. Before implantation, the wafer was pre-sputtered using DC bias of 300B in Ar plasma in order to eliminate the native oxide. After cleaning, B2H6 (5%)/H2 plasma and negative pulse bias of -1kV to 5 kV were used to form shallow p+/n junction at the boron dose of 1$\times$1015 to 5$\times$1016 #/cm2. The as-implanted samples were annealed at 90$0^{\circ}C$, 95$0^{\circ}C$ and 100$0^{\circ}C$during various annealing time with rapid thermal process. After annealing, the sheet resistance and the junction depth were measured with four point probe and secondary ion mass spectroscopy, respectively. The doping uniformity was also investigated. In addition, the electrical characteristics were measured for Schottky diode with a current-voltage meter.

• STI Policy Review
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• v.5 no.2
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• pp.65-95
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• 2014

The recent decades have seen a growing rate of international cooperation in science, technology, and innovation (STI) including in the field of green technologies. However, current approaches to national systems of innovation (NSI) have not kept up with this development. International aspects are rather treated as external conditions within which policymakers operate and respond but not influence. This paper tackles this problem by applying a refined NSI concept that includes an international dimension and complements past frameworks by focusing on those Korean government policies, actors, and activities relevant for the internationalization of STI. Austria and Korea have both formulated differing strategies to acquire international leading positions in the field of innovation and the development of green technologies. In the first step, the paper assesses Korea's international activities within the field of green technologies that transcend national boundaries and establish international connections. The government has still a strong influence on selecting technology areas for strategic funding but our findings show that international STI actors have difficulties in identifying the appropriate point of contact to initiate cooperation or apply for related funding. Second, an external perspective on Korea's international collaborations in the field of green technologies is offered. Austria has tentatively identified the East Asian country as a second-priority cooperation partner for its future STI internationalization activities. Interviews with Austrian stakeholders in the field of green technologies indicate a high interest in cooperation with Korea that is facilitated by a similar business culture based on personal networks. Moreover, researchers and policymakers referred to a shared need of small countries for intelligent decision-making processes regarding potential cooperation partners abroad. However, in order to enhance awareness, visibility and demand for Korean STI cooperation in European countries, more long-term funding programs featuring a more permanent point of contact should be introduced.

• The Journal of the Korea Contents Association
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• v.21 no.9
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• pp.543-556
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• 2021

The purpose of this study is to examine possible improvements of operation of sign language interpreter qualification system through looking into specific perceptions of sign language interpreters and Deaf sign language interpreters in the field and Deaf people who use interpretation service on current sign language interpreter qualification system through focus group interview. As a result of the thematic analysis, three high-level categories were derived for each group, and as a result of recombining them, 'change to a qualification system in which sign language interpreting competency and expertise can be recognized' and 'improvement to a qualification system based on Korean Sign Language and Deaf culture' been sorted out. Based on the above research results, 'establishment of a permanent institution in charge of management and operation of sign language interpreter qualification tests', 'reorganization into a qualification system that reflects the professionalism, level and experience of sign language interpreters', 'all test questions and exam procedures are conducted mainly in sign language', 'a system in which the Deaf take the lead', and 'enactment of a code of ethics for sign language interpreters and Deaf interpreters' were suggested.

• Tribology and Lubricants
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• v.35 no.2
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• pp.114-122
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• 2019

High-speed rotating machinery requires low cost and reliable bearing elements with low friction, stable rotordynamic characteristics, and a simple design. This study experimentally evaluates the effects of bearing-support elements on the vibrational characteristics of a small-sized, high-speed permanent magnetic motor. A series of coast down tests from 100 krpm characterize the vibrational behaviors, rotor displacement, and housing acceleration of motors supported by ball bearings, ball bearings with a metal mesh damper, and gas foil bearings, respectively. Two eddy-current sensors installed in the horizontal and vertical directions measure the displacement of the rotor at its front nut, and a 3-axis accelerometer attached to the motor housing measures the housing acceleration. The test results reveal that synchronous (1X) vibration components most significantly affect the rotor displacement and housing acceleration, independent of the bearing-support elements. The motor supported by the deep-groove ball bearings results in the largest rotor vibrations increasing with speed; this is due to the absence of a damping mechanism. Additionally, the metal mesh damper effectively reduces the rotor displacement, housing acceleration, and sound-pressure level in the high-speed region (i.e., above 40 krpm), thus implying its substantial damping performance when installed on the outer race of the ball bearing. Lastly, the gas foil bearing supported motor yields the smallest rotor displacement, housing acceleration, and lowest sound-pressure level because of its hydrodynamic airborne operation, which does not require rolling elements that may cause mechanical friction and vibrations.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.1
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• pp.1017-1030
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• 2021

Constructed upon Knowledge Management (KM) processes, the current study aims to investigate the interrelationship between Knowledge Sharing (KS) attitude among the faculty members and KM processes in higher education institutes (HEIs) in Pakistan along with the intervening role of subjective norms between KM processes and KS attitude. This research incorporated the theory of Planned Behavior (TPB) and the theory of Reasoned Action (TRA) to conceptualize the KS behavior by using a sample frame of 302 academic and administrative staff from research-based HEIs in Quetta, Pakistan. A questionnaire-based survey was conducted on permanent faculty members from different universities of Quetta, Pakistan. The finding of the study shows a positive attitude among the researchers. The study empirically examined the interface between KM processes and KS attitude and higher education performance while providing valuable insights into the prevailing literature by investigating the mediating role of subject norms. The impact of subjective norms on KS attitude and KM process indicates the importance and basic determinant in organizational premises and improvement of skills of faculty management in HEIs. The partial mediation also reveals the importance of subjective norms in the development of faculty members' KM and KS attitude process.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.4
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• pp.73-94
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• 2020

The purpose of this study is to identify the current status of staff in school libraries and to provide suggestions for the development of these facilities through the job satisfaction of itinerant librarians, who act as support for schools which lack permanent staff. For employees in the South Korean provinces of South Jeolla, North Gyeongsan and South Gyeonsan, regions which currently operate using systems of itinerant librarians, the general status, work characteristics and systems were identified, and job satisfaction was surveyed. As a result of the survey, librarians may be in charge of anywhere from ten to two hundred schools, with approximately 30% of them being affiliated with public libraries in various municipalities. The overall job satisfaction averaged out to a score of 3.45 out of 5, with the categories of duties (4.15), a feeling of accomplishment (3.89) and communication (3.70) showing above average results, while opportunities for promotion (2.08) and job training (1.96) were on the lower end of the scale. For better job satisfaction, this study suggests an increase in the number of itinerant librarians, more job training, and having these professionals be affiliated with school boards rather than public libraries.

• 한국사회정책
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• v.23 no.1
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• pp.151-178
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• 2016

This study aims to look at the current status of college graduate youth' participating in Individual Training Account System of Korea and analyze the effects of their participation experience on the labor market outcomes. To achieve this, this study used the data from 2012 Graduates Occupational Mobility Survey(GOMS) and for analysis, used both multiple regression analysis and binomial logistic regression analysis. As a result, it was found that the number of young people who had ever heard about the Individual Training Account System was 2,707 individuals (27.6%), and among them, the number of young people who had actually participated in the System was 695(25.7%). As a result of analyzing the effect of participation experience with the Individual Training Account System on the outcomes of labor market, it was found that participation experience had a positive and significant impact on whether they were employed and the form of employment (permanent position), whereas it did not have a positive impact on average monthly wage. Based on these results, this study drew implications for further studies and suggested policy tasks for improving the policy effectiveness of the Individual Training Account System.