• 에너지공학
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• 제23권4호
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• pp.123-129
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• 2014

국내에서도 에너지절약성과 보증계약 방식 위주의 역량강화를 위한 측정 검증(M&V)이 중요한 과제로 부각됨에 따라 선진국과 같은 M&V 방법의 선택과 적용이 필요하다. 국내 ESCO 산업의 역량강화를 촉진하기 위해 에너지절약성과에 대한 M&V를 위해서, 적합한 M&V 선택 및 적용방안의 제시가 요청되고 있다. 본고에서는 IPMVP, 미국 및 일본 사례를 참조하여 국내의 M&V 적용목표 및 적용방향을 설정하고, 적용절차 및 유의사항을 설명한 뒤 M&V 방안(A, B, C, D)의 선택 및 검증방안을 제시하였다. 향후 연구과제로 앞에 제시된 M&V 선택 및 적용방안을 기초로 한 M&V 계획서 및 결과서 작성을 위한 가이드라인 제시방안이 마련될 필요가 있다.

• 대한전자공학회논문지SD
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• 제46권8호
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• pp.31-40
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• 2009

본 논문은 SoC 전원 관리를 위한 고성능 DC-DC 부스트 변환기 설계에 관한 것이다. DC-DC 변환기에서 일반적으로 전하 축전용으로 사용되는 인덕터와 커패시터를 칩 안에 집적하기 위해 그 크기를 크게 감소시키고, 스위칭 주파수를 100MHz로 하였다. 고속 동작에서 전압 방식의 제어를 선택하여 신뢰성을 높였으며 적절한 주파수 보상으로 안정적인 동작 특성을 확보하였다. 설계한 DC-DC 변환기는 thick gate oxide 옵션이 포함된 0.18${\mu}m$ CMOS 표준 공정으로 제작하였다. 내부 필터 커패시터를 포함한 칩의 면적은 8.1$mm^2$ 이고, 제어기가 차지하는 면적은 1.15$mm^2$ 이다. 부하 전류 300mA 이상에 대하여 4V의 출력을 얻는 변환기의 최대 효율은 76% 이상, load regulation은 100mA의 변화에 대하여 0.012% (0.5mV) 의 특성을 갖는다.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.551-559
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• 2015

This paper's focus is in reducing the torque ripple and increasing the average torque by optimizing switching angles of 8/6 switched reluctance motor while implementing a robust speed controller in the outer loop. The mathematical model of the machine is developed and it is simulated using MATLAB/Simulink. An objective function and constraints are formulated and Optimum turn-on and turn-off angles are determined using Particle swarm optimization and Genetic Algorithm techniques. The novelty of this paper lies in implementing sliding mode speed controller with optimized angles. The results from both the optimization techniques are then compared with initial angles with one of them clearly being the better option. Speed response is compared with PID controller.

• Journal of Chest Surgery
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• 제50권4호
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• pp.281-286
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• 2017

Background: In chemical pleurodesis for managing pulmonary air leak, tetracycline derivatives are commonly used, and their effectiveness has been established in many studies. Recently, a Viscum album extract was used in chemical pleurodesis. We compared the effects of V. album with those of a tetracycline derivative (doxycycline) to demonstrate the therapeutic effectiveness of the V. album extract in chemical pleurodesis for managing pulmonary air leak. Methods: Between October 2010 and October 2016, chemical pleurodesis was performed using doxycycline in 40 patients and the V. album extract in 37 patients. Thirty-three patients were in the postoperative state after pulmonary resection, and 44 patients suffered from spontaneous pneumothorax. Results: No statistically significant difference in the success rate was observed between the 2 groups (V. album extract and doxycycline). In both groups, chest pain was the most common complication. More patients in the doxycycline group complained of severe chest pain (42.1% vs. 13.5%, p=0.006). In the V. album extract group, 24.3% of the patients required a chest tube to drain the pleural effusion after cessation of the air leak (doxycycline group: 5%, p=0.022). Further, the amount of pleural effusion drained on the day after the last chemical pleurodesis in the V. album extract group was greater than that in the doxycycline group ($162.2{\pm}170.2mL$ vs. $97.0{\pm}77.2mL$, p=0.032). All patients were discharged from the hospital without complications after pleural effusion drainage. Conclusion: Considering that treatment using the V. album extract was less painful, V. album might be a feasible option for chemical pleurodesis. However, pleural effusion should be monitored carefully when using V. album extract for treating patients suffering from air leak.

• JSTS:Journal of Semiconductor Technology and Science
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• 제10권4호
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• pp.316-324
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• 2010

In this paper, we design a 256 kbits EEPROM for a MCU (Microcontroller unit) with the wide voltage range of 1.8 V to 5.5 V. The memory space of the EEPROM is separated into a program and data region. An option memory region is added for storing user IDs, serial numbers and so forth. By making HPWs (High-voltage P-wells) of EEPROM cell arrays with the same bias voltages in accordance with the operation modes shared in a double word unit, we can reduce the HPW-to-HPW space by a half and hence the area of the EEPROM cell arrays by 9.1 percent. Also, we propose a page buffer circuit reducing a test time, and a write-verify-read mode securing a reliability of the EEPROM. Furthermore, we propose a DC-DC converter that can be applied to a MCU with the wide voltage range. Finally, we come up with a method of obtaining the oscillation period of a charge pump. The layout size of the designed 256 kbits EEPROM IP with MagnaChip's 0.18 ${\mu}m$ EEPROM process is $1581.55{\mu}m{\times}792.00{\mu}m$.

• Advances in materials Research
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• 제12권2호
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• pp.119-131
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• 2023

The development of sustainable composites materials, from recycled polymeric materials and waste from the wood industry and stone processing, allows reducing the volume of these by-products, minimizing impacts on health and the environment. Nowadays, Polypropylene (PP) is the most recycled polymer in industry, while the furniture industry has increasingly used timber felled from sustainable forest plantations as a eucalypt. The powder tailing from the ornamental stone extraction and processing industry is commonly disposed of in the environment without previous treatment. Thus, the technological option for the development of composite materials presents itself as a sustainable alternative for processing and manufacturing industries, enabling the development of new materials with special technical features. The results showed that powder granite particles may be incorporated into the polypropylene matrix associated with short eucalyptus fibres forming green hybrid composites with potential application in structural engineering, such as transport and civil construction industries.

• 대한전자공학회논문지SD
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• 제43권9호
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• pp.23-30
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• 2006

본 논문은 전류 감지 feedback 기법을 사용한 고효율 CMOS DC-DC boost 변환기의 설계에 관한 것이다. 펄스-폭 변조 방식의 스위칭 동작을 위해 인덕터를 통해 흐르는 전류의 양을 감지하는 고해상도 전류 감지 회로를 설계하였다. 이를 통하여 외부 소자나 큰 면적을 차지하는 주파수 보상 회로 없이 안정적으로 동작하는 변환기 성능을 얻을 수 있다. 또한 외부 저항 열을 사용하여 다양한 입력/출력 전압 특성을 얻을 수 있다. 설계한 DC-DC 변환기는 thick gate oxide 옵션이 포함된 0.18-um CMOS 표준 공정으로 제작하였다. 부하 전류 200mA 이상에 대하여 3.3V의 출력을 얻는 변환기에서 최대 효율은 90% 이상, load regulation은 100mA의 변화에 대하여 1.15%의 특성을 나타낸다.

• 한국정보통신학회논문지
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• 제24권2호
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• pp.325-328
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• 2020

This paper demonstrated a voltage-controlled oscillator (VCO) using cost-effective (1-poly 6-metal) mixed signal standard CMOS process. To have the high-quality factor inductor in LC resonator with thin metal thickness, patterned-ground shields (PGS) was adopted under the spiral to effectively reduce the ac current of low resistive Si substrate. And, because of thin top-metal compared with that of RF option (2 ㎛), we make electrically connect between the top metal (M6) and the next metal (M5) by great number of via array along the metal traces. The circuit operated from 2.48 GHz to 2.62 GHz tuned by accumulation-mode varactor device. And the measured phase noise of LC VCO has -123.7 dBc/Hz at 1MHz offset at 2.62 GHz and the dc-power consumption shows 2.07 mW with 1.8V supply voltage, respectively.

• 한국전기전자재료학회논문지
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• 제20권6호
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• pp.491-495
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• 2007

This paper has demonstrated the electrical properties of SiGe pMOSFETs fabricated on both bulk-Si and PD SOI substrates. Two principal merits, the mobility increase in strained-SiGe channel and the parasitic capacitance reduction of SOI isolation, resulted in improvements in device performance. It was observed that the SiGe PD SOI could alleviate the floating body effect, and consequently DIBL was as low as 10 mV/V. The cut-off frequency of device fabricated on PD SOI substrate was roughly doubled in comparison with SiGe bulk: from 6.7 GHz to 11.3 GHz. These experimental result suggests that the SiGe PD SOI pMOSFET is a promising option to drive CMOS to enhance performance with its increased operation frequency for high speed and low noise applications.

• 대한조선학회논문집
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• 제45권3호
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• pp.337-343
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• 2008

There are various hull types on the mid-size superyachts around $30\;{\sim}\;45m$. In any case, it is important to design the proper hull shape in viewpoint of the reduction of wave resistance, because small vessels such as superyachts are running at relatively higher Froude Number than other merchant ships. FLUENT with a VOF option was employed to investigate the flow fields around the superyachts having three-typical hull types: U-, V-types and catamaran. Overall performances including free surface flow were compared to figure out hydrodynamic characteristics of superyachy by numerical simulation.