• Journal of Power Electronics
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• v.12 no.6
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• pp.895-903
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• 2012

This paper presents a fast switching direct torque control (FS-DTC) using only a single DC-link current sensor. In FS-DTC, six new active voltage complex space vectors (CSVs) are synthesized by the conventional active voltage space vectors (SVs). The corresponding sectors are rotated in the anticlockwise direction by 30 degrees. A selection table is defined to select the CSVs. Based on the "Different Phase Mode", the output sequence of the selected CSV is optimized. Accordingly, a reconstruction method is proposed to acquire the phase currents. The core of the FS-DTC is that all of the three phase currents can be reliably reconstructed during every two sampling periods, which is the result of the fast switching between different phases. The errors between the reconstructed and actual currents are strictly limited in one sampling period. The FS-DTC has the advantages of the standard DTC scheme such as simple structure, quick torque response and robustness. As can be seen in the analysis, the FS-DTC can be thought of as an equivalent standard DTC scheme with 86.6% of the maximum speed, 173.2% of the torque ripple, and 115% of the response time of the torque. Based on a dSPACE DS1103 controller, the FS-DTC is implemented in an induction machine drive system. The results verify the effectiveness of the FS-DTC.

• Structural Engineering and Mechanics
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• v.87 no.4
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• pp.347-361
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• 2023

This research aims to assess the behavior of reinforced concrete (RC) residential buildings when moment-resisting frames (MRFs) are used as the lateral resisting system. This investigation was conducted using MIDAS Gen v.19.0. Buildings with various plan footprints (Square, Rectangular, Circular, Triangular, and Plus-Shaped), and different heights (15 m, 30 m, 45 m, and 60 m) are investigated. The defined load cases, the equivalent static lateral load pattern, and the response spectrum function were defined as stated by the American Standard (ASCE 7-16), the 1997 Uniform Building Code (UBC97), the Egyptian Code for Loads (ECP-201), and the European Standard (EC8). Extensive comparisons of the results obtained by the different codes (including the story displacement, the story drift, and the base shear) were undertaken; to assess the response of moment-resisting multi-story framed buildings under lateral loads. The results revealed that, for all study cases under consideration, both ECP-201 and EC8 gave smaller base shear, displacement, and drift by one third to one fourth, around one fourth, around one fifth, respectively for both the ELF and RSA methods if compared to ASCE 7-16 and UBC97.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.69-77
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• 2023

Recently, carbon composites have been applied to various fields. However, carbon composites have not been applied to the fishing vessel field due to its structure standards centered on glass composites. In this study, a structural strength evaluation study was conducted for the application of carbon composites in the fishing vessel field. Hull minimum thickness verification test and hull joint verification test were conducted. Compared to glass composites, the verification was based on equivalent or better performance. The results show that carbon composites can reduce the weight by 20% compared to glass composites. For hull joints, it was necessary to increase the thickness of the joint seam by the thickness of the hull to apply carbon composite. Through this study, a standard for the application of carbon composites to fishing vessel can be established.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.727-732
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• 2008

Recently, according to the increase of using the microwave equipments, the interests in effects on human body have been also increased. For example, there have been many researches on making the standard the specific absorbing ratio (SAR) caused by mobile phones. However, it is needed to study on the induced current on human body caused by HF(Hight Frequency) band which can deeply penetrate the human body. Especially, since the RFID systems are applied to the transportation card and the library, it is hooded to research on the effect on human body exposed to the radiated power from the RFID system. In this paper, we designed a cylindrical monopole antenna model of human body exposed to 13.56 MHz RFID system, which can model the induced current on human body. To verify the proposed equivalent antenna model, we compared the induced currents between human body and the equivalent antenna model.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.17 no.4
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• pp.531-538
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• 2010

Purpose: This study was done to identify the effects of Qi hand reflexology on autonomic nerve activity in patients admitted to hospital. Method: A non-equivalent control group and quasi-experimental research with pre/post test design were used and 59 patients on a medical ward were assigned to either the experimental group (32) or the control group (27). The study variables included vital signs, autonomic nerve activities (ALF (absolute low frequency), AHF (absolute high frequency), nLF (normalized low frequency), nHF (normalized high frequency), SDNN (standard deviation of all normal-normal intervals)) and were evaluated using the QECG-3 system. The experimental group was treated with Qi hand reflexology for 10 minutes per day, for 3days. Results: Skin temperature and systolic blood pressure in the experimental decreased with treatment. ALF, AHF and SDNN for the experimental group increased with regulating proportion (nLF: nHF=6:4) and a significant difference between the groups was observed. Conclusion: The results indicated that application of Qi hand reflexology for patients in the hospital is effective in regulating the autonomic nervous system activation. Implication of finding should be useful for future research.

• Journal of Energy Engineering
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• v.26 no.4
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• pp.92-99
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• 2017

In Korea, the zero energy building was designated as the 7 new industries in the Ministry of Land and the 8 new industries in the Ministry of Industry. In order to maximize the insulation performance of the building envelope, improve the efficiency of building equipment, We are aiming. It is necessary to analyze the energy requirements of the buildings (cooling, heating, hot water supply, lighting, ventilation) of buildings with energy efficiency level of 1++ which is equivalent to the zero energy building certification system in Korea, It is aimed to be used as basic data for the advancement of energy building certification system. Zero Energy Building certification is estimated to be 61 buildings by 2017, and the approximate reference value and the first energy requirement for each of the five loads are calculated considering passive and active aspects. It is difficult to say that it is a clear standard because there is a small sample of data for calculating the load standard. However, it is necessary to interpret various methods in order to upgrade the Zero Energy Building certification standard in the future.

• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.681-688
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• 2004

For use of the thermal cycle of the biochemical fluid sample, the isothermal temperature source with a large surface area was designed, fabricated and its thermal characterization was experimentally evaluated. The comprehensive overview of the technology trend on the temperature control devices was detailed. The large surface area isothermal temperature source was realized by using the vapor chamber heat spreader. The cost-effectiveness and simple manufacturing process were achieved by using the metal-etched wick structure. The temperature distribution was quantitatively investigated by using IR temperature imaging system at equivalent temperatures to the PCR thermal cycle. The standard deviation was measured to be within 0.7$^{\circ}C$ for each temperature cycle. This concludes that the presented isothermal temperature source enables no temperature gradient inside bio-sample fluid. Furthermore it can be applied to the cooling of the electronic devices due to its slimness and low thermal spreading resistance.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2032-2033
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• 2008

We have developed an evaluation technique for phase displacement of current transformer (CT) comparator by using the precise standard capacitors and resistors. By applying this technique for equivalent circuit of CT comparator evaluation system, we can obtain the calculated and measured phase displacement in the CT comparator. Thus we can evaluate phase displacement of CT comparator by comparing the calculated and measured phase displacement. The method was applied to CT comparator under test with the phase displacement ranges of $0{\sim}{\pm}7.5$ crad. Finally we have compared the phase displacement of the CT comparator under test theoretically obtained in this method with the specification.

• Journal of Power Electronics
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• v.9 no.2
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• pp.308-319
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• 2009

An increasing number of power electronic applications require high power density. Therefore, the switching frequency and switching speed have to be raised considerably. However, the very fast switching transients induce a strong voltage and current ringing. In this work, a novel damping concept is introduced where the parasitic wiring inductances are advantageously magnetically coupled with a damping layer for attenuating these unwanted oscillations. The proposed damping layer can be implemented using standard materials and printed circuit board manufacturing processes. The system behavior is analyzed in detail and design guidelines for a damping layer with optimized RC termination network are given. The effectiveness of the introduced layer is determined by layout parasitics which are calculated by application of the Partial Element Equivalent Circuit (PEEC) simulation method. Finally, simulations and measurements on a laboratory prototype demonstrate the good performance of the proposed damping approach.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.1
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• pp.24-28
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• 2006

This paper presents a power transfer capability calculation algorithm considering transient stability, The theoretical development is straightforward: dynamic equations are converted to numerically equivalent algebraic equation and then integrated into the standard formulation for power transfer capability calculation. The proposed method is applied to IEEE-24 Reliability Test System and the results shows the effectiveness of the method.