• The Korean Journal of Archival Studies
• /
• no.37
• /
• pp.273-305
• /
• 2013

In order to actively use of records and information in current digital record management systems, we have to check whether a system is designed to fully support the user of records and whether the good use of the system is being. This study analyzed the status of the use of the search function of Records Management System(RMS) for public agencies, and evaluated them. In order to investigate the status of the use of the search function, it surveyed records managers of public agencies using the RMS. The result showed that records managers unsatisfied with the usability and the search performance of the RMS. To evaluate the search function, it identified the functional requirement of the system and develops a checklist that can be used for evaluation. Two assessments were conducted. Firstly, as pre-evaluation, it assessed the degree of implementation of the current RMS according to the checklist as an inspection chart using document examination method. Secondly, it assessed the degree of implementation using a survey of records managers of public agencies that use the RMS. Assessment results show the improvement of the basic features that are essential to the system is required. In particular, the search function is required to improve user-friendliness for the user. For the advance of RMS, this study discusses the necessity for improvement of the search functions, the build of continuous maintenance and management system, and the user education.

• Journal of Power Electronics
• /
• v.16 no.4
• /
• pp.1288-1297
• /
• 2016

This study proposes a single-stage light-emitting diode (LED) tube lamp driver with input-current shaping for T8/T10-type fluorescent lamp replacements. The proposed AC-DC LED driver integrates a dual-boost converter with coupled inductors and a half-bridge series-resonant converter with a bridge rectifier into a single-stage power conversion topology. This paper presents the operational principles and design considerations for one T8-type 18 W-rated LED tube lamp with line input voltages ranging from 100 V rms to 120 V rms. Experimental results for the prototype driver show that the highest power factor (PF = 0.988), lowest input current total harmonic distortion (THD = 7.22%), and highest circuit efficiency (η = 92.42%) are obtained at an input voltage of 120 V. Hence, the proposed driver is feasible for use in energy-efficient indoor lighting applications.

• KEPCO Journal on Electric Power and Energy
• /
• v.1 no.1
• /
• pp.151-156
• /
• 2015

In order to improve the properties of high-temperature superconducting wire for superconducting cable system, we optimized the electro-polishing (EP), ion-beam assisted deposition (IBAD), superconducting (SC) layer, and baking (heat) treatment. The buffer layer was deposited on electro-polished substrate with RMS roughness ($R_{RMS}$) less than 5 nm. The IBAD process was carried out at $V_{beam}$: 1100 V and $V_{accel}$: 850 V that resulted in highly crystalline film of $LaMnO_3$. Chemical composition of SC layer is key to higher critical current, and we found that composition can be determined by surface color of SC layer. We adopt a proprietary contorl system based on RGB analysis of the surface and achieved critical current of 150 A/4 mm-width. The proposed baking treatment resulted in decreasing of about 10% of fraction defects.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.11
• /
• pp.737-741
• /
• 2000

We fabricated resistive superconducting fault current limiters (SFCL) based on YBCO thin films grown on 2-inch diameter $Al_2O_3$ substrates. Two SFCLs with nearly identical properties were connected in series to investigate simultaneous quench. There was a slight difference in the rate of voltage increase between two SFCL units when they were operated independently. This difference resulted in significantly imbalanced power dissipation between the units. This imbalance was removed by connecting a shunt resister to an SFCL in parallel. The appropriate values of shunt resistance were 80 ${\Omega}$ at 75 $V_rms$ and 110 ${\Omega}$ at 120 $V_rms$, respectively. Increased power input at high voltages also reduced the initial imbalance in power dissipation, but with increase in film temperature to higher than 200 K.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.517-520
• /
• 2003

The purpose of this paper is to investigate the effect of arc current and contact velocity on the erosion of silver contact to be used in low voltage circuit breakers. The arc current range from $2kA_{rms}$ to $20kA_{rms}$. A test system allows the control of the opening velocity profiles with contact velocities up to 10m/s and also enables the synchronization of the contact opening with a point on the arc current waveform. Contact erosion is evaluated by measuring the mass change of the cathode and anode. The results show that increase the opening velocity from 2m/s to 6m/s leads to an decrease in the contact erosion. The material transfer from one electrode to another is shown to depend on the transfer charge and the opening velocity of the contacts.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.27 no.3
• /
• pp.214-220
• /
• 2022

This paper proposes a test device designed for developing a high-voltage multilayer ceramic capacitor (MLCC). The proposed topology consists of an energy recovery circuit for charging/discharging capacitor, a flyback converter, and a boost converter for supplying power and a bias voltage application to the energy recovery circuit. The energy recovery circuit designed with a half-bridge converter has auxiliary switches operating before the main switches to prevent excessive current from flowing to the main switches. A prototype has been designed to verify the reliability of target capacitors following the voltage fluctuation with a frequency range below 65 kHz. To conduct high root mean square (RMS) current to the capacitor as a load, the MLCC test was conducted after the topology verification was completed through the film capacitor as a load. Through the agreement between the RMS current formula proposed in this paper and the MLCC test results, the possibility of its use was demonstrated for high-voltage MLCC development in the future.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.27 no.4
• /
• pp.325-331
• /
• 2022

This study proposes a design method that minimizes a conduction loss of LCC resonant converter under rated condition. Through a simplified analysis of the waveform of the resonant current, the power transfer section and RMS value of the resonant current was analyzed mathematically and graphically. Based on this analysis, the design method that minimizes the RMS value of the resonant current is proposed. To demonstrate this method, this study designed a 7.5 kW (100 V, 75 A) capacitor charger based on LCC resonant converter and the design parameters were chosen according to the process of the design method. Then, the capacitor charger was implemented. An experiment was conducted to measure efficiency while satisfying design specifications under rated conditions. This design method was verified to be effective by achieving 97.7% maximum efficiency and design specifications under rated conditions.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.7
• /
• pp.4089-4093
• /
• 2013

Objective: The rhabdomysarcoma (RMS) is most common soft tissue carcinoma in children, mostly found in the head and neck with high degree of malignancy. The current study aimed to summarize clinical data and evaluate treatment outcome of cases in a single hospital. Methods: Forty-one (24 male, 17 female) children with newly diagnosed RMS in Beijing Tong Ren Hospital were enrolled between November, 2004 and May, 2011. The. Students' t and Chi tests were then performed on retrospectively reviewed clinical data, followed by survival analysis based on the Kaplan Meier method using SPSS 17.0 software. Results: Of all cases, 32 were treated by common chemotherapy, and 3 cases with stage III RMS received high-dose chemotherapy and auto-peripheral blood stem cell transplantation (APBSCT). Side-effects in the former were: I grade for 62.5% (20/32), II grade for 28.1% (9/32), III grade account for 9.275% (3/32). Side-effects of 3 cases with APBSCT: 2 were I grade, 1 was III grade. The median follow-up time of 41 RMS cases was 41 months. Four cases were lost to follow-up, 7 cases recurred, and 5 cases died of cerebral metastasis, witha total survival rate was 86.5% (32/37). CR rate was 67.6% (25/37), PR was 18.9% (7/37). Conclusion: Multidiscipline treatment including chemotherapy, radiotherapy, surgery and auto-PBSCT is highly recommended for pediatric patients with head and neck RMS.

• Progress in Superconductivity and Cryogenics
• /
• v.19 no.1
• /
• pp.26-29
• /
• 2017

We studied the distribution of the current density and its magnetic-field dependence in GdBCO coated conductors with AC bias currents using low temperature scanning Hall probe microscopy. We selectively measured magnetic field profiles from AC signal obtained by Lock-in technique and calculated current distributions by inversion calculation. In order to confirm the AC measurement results, we applied DC current corresponding to RMS value of AC current and compared distribution of AC and DC transport current. We carried out the same measurements at various external DC magnetic fields, and investigated field dependence of AC current distribution. We notice that the AC current distribution unaffected by external magnetic fields and preserved their own path on the contrary to DC current.

• Progress in Superconductivity and Cryogenics
• /
• v.9 no.4
• /
• pp.32-36
• /
• 2007

We fabricated and tested a novel hybrid superconducting fault current limiter (SFCL) of three-phase $24kV_{rms}/630A_{rms}$ rating. In order to apply conventional resistive SFCLs into electric power systems, the urgent issues to be settled are as follows, such as initial installation price of SFCL, operation and maintenance cost due to ac loss of superconductor and the life of cryostat, and high voltage and high current problems. The ac loss and high cost of superconductor and cryostat system are main bottlenecks for real application. Furthermore in order to increase voltage and current ratings of SFCL, a lot of superconductor components should be connected in series and parallel which resulted in extreme high cost. In addition, the method to quench all components at the same instant needs very sophisticated skill and careful operation. Due to these problems, the practical applications of SFCL were pending. Therefore, in order to make practical SFCL, the price of SFCL should be lowered and should meet the demand of utilities. We designed novel hybrid SFCL which combines superconductor and conventional electric equipment including vacuum interrupter, power fuse and current limiting reactor. The main purpose of hybrid SFCL is to drastically reduce total usage of superconductor by adopting current commutation method by use of superconductor and high fast switch. Consequently, it was possible to get the satisfactory test results using this method, and further works for field tests are in the process.