• 전기학회논문지P
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• 제56권3호
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• pp.129-135
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• 2007

This paper deals with speed-sensorless control of DC servo motor using Neuro-Fuzzy Observer. DC servo motor has very low rotor inertia and excellent response characteristic and it is very useful to control torque and speed. It is easy to detect the voltage and current and resolver or encoder is used to measure a rotor speed. But it has a limit as a driving speed to detect speed precisely. So it is problem to improve the performance of the driving system. To solve this problem, it is studied to detect a speed of DC servo motor without sensor. In particular, study on the method to estimate the speed using the observer is performed a lot. In this paper, the gain of the observer is properly set up using the Neuro-Fuzzy control and Neuro-Fuzzy Observer that have a superior transient characteristic and is easy to implement compared the existing method is designed. It calculates the differentiation of the rotor current directly using the rotor current measured in the DC servo motor and estimates the speed of the rotor using the differentiation. Proposed speed sensorless control method is performed using the estimated speed. Also, it is proved feasibility of the proposed observer from the comparison tested a case with a speed sensor and a case without a speed sensor which used a highly efficient drive and 200[w] DC servo motor starting system.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.475-478
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• 2006

Total primary production resulting from the photosynthetic process can be defined as the amount of organic matter produced in a given period of time. It is proportional to the chlorophyll-a (chl-a) values in the surface layer of the ocean. The MODIS board on Aqua satellite measures visible and infrared radiation in 36 wavebands, providing simultaneous images of chl-a concentration and sea surface temperature (SST) in the upper layer of the sea. The seasonal distribution of chl-a concentration during one year from April 2005 to March 2006 was examined. Light has a role of starting the seasonal cycle. The Kuroshio Current in this area induces many oceanographical features affecting to the change of seasonal control. The chl-a concentration is also seasonal, which is low in summer and high in winter. In summer, the meandering of Kuroshio Current induces strong eddies and increases the chl-a concentration. In autumn, the delayed small autumn bloom occurred until last December due to the Kuroshio Current. When the Kuroshio axis moves far from the coast, the coastal water dominates and increases the concentration even in the winter. The spring bloom starts early at the beginning of March and decreases during the spring.

• Journal of Power Electronics
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• 제2권2호
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• pp.146-153
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• 2002

this paper presents an implementation of digital control system of speed sensorless for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The problem of DTC for high-dynamic performance RSM drive is generating a nonlinear torque due to a saturated nonlinear inductance curve with various load currents. The control system consists of stator flux observer, compensating inductance look-up table, rotor position/speed/torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source unverter, and TMS320C31 DSP controller. The stator flux observer is based on the combined voltage and current model with stator flux feedback adapitve control that inputs are the compensated inductances, current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated rotor speed is determined by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operation area. It does not requrie the knowledge of any montor paramenters, nor particular care for moter starting, In order to prove the suggested control algorithm, we have simulation and testing at actual experimental system. The developed sensorless control system is showing a good speed control response characterisitic result and high performance features in 20/1500 rpm with 1.0Kw RSM having 2.57 ratio of d/q reluctance.

• Asian-Australasian Journal of Animal Sciences
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• 제32권8_spc호
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• pp.1256-1265
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• 2019

The aim of this review is to show the evolution of the dairy goat sector in Europe from all perspectives. Starting from the current situation, the challenges and future potential of this livestock system are presented, as well as strategies to overcome the difficulties faced. Europe holds 1.9% of the world goat population and produces 15.1% of goat milk recorded worldwide. The goat species plays a fundamental economic, social and environmental role in many regions of Europe. The wide diversity of production systems and autochthonous breeds makes the sector very heterogeneous. In order to improve viability, a number of strategies need to be adopted to solve the current problems such as a low profitability, absence of generational change and a little or no recognition of the social and environmental role of the sector. Some strategies to improve the situation of the European goat sector include: i) generating market value that will recognise the diversity of the dairy goat sector (breeds, feeding models, derived products${\ldots}$); ii) promoting and raising awareness of the functional attributes of goat milk and derived products so as to increase consumption; iii) assigning an economic value to environmental and social functions; iv) improving working conditions through technological innovation to make goat farming more attractive to young people; and v) processing more milk into cheese or other dairy products in production areas.

• Journal of Digestive Cancer Research
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• 제11권2호
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• pp.85-92
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• 2023

Colorectal cancer (CRC) is one of the most prevalent cancers and is the leading cause of cancer-related mortality worldwide. Based on the current screening guidelines by the American Cancer Society and Korean multi-society expert committee, CRC screening is recommended in asymptomatic adults starting at the age of 45 years. Fecal immunochemical test-based screening programs reduce the development of CRC and related mortality in the general population. However, this most popular CRC screening strategy demonstrates a crucial limitation due to modest diagnostic accuracy. Colonoscopy may be considered as an alternative primary method for CRC screening; however, its implementation can still be challenging due to concerns regarding invasiveness, low adherence, cost-effectiveness, and quality assurance. To overcome the limitations of current screening tests, innovative noninvasive tests for CRC screening have been developed with advances in molecular biology, genetics, epigenetics, and microbiomics for detecting CRC, which may enhance the approach to CRC screening and diagnosis in clinical practice in the near future. This review explores the emerging screening methods and discusses their potential for integration into current practice.

• 전자공학회논문지S
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• 제35S권10호
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• pp.52-63
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• 1998

본 논문에서는 기존의 멀티캐스트 패킷 교환기의 문제점에 대한 개선 방안을 제안한다. 오버플로우에 의해 야기 되는 입력포트의 공평성 문제는 임의의 입력 포트로부터 복사 수를 가산 할 수 있는 동적 시작점 결정기에 의해 해결된다. 시작점은 매 타임 슬롯 마다 입력 버퍼의 점유도와 이전 타임 슬롯의 오버플로우를 기반으로 가변 된다. 입력 버퍼의 점유도를 이용함으로서 제안된 복사망은 기존의 방식에 비해 입력 트래픽의 변동에 대하여 우수한 적응성을 제공한다. 동적 시작점 결정기는 입력 트래픽의 양에 따라 복사 요청의 수를 제어하며 이것은 복사망의 전체 스루풋을 제고하는 필수적인 기능 이다. 오버플로우 발생시에 멀티캐스트 스위치의 스루풋을 향상시키는 호-분할(call-splitting) 방식도 동적 시작점 결정기에 의해 제공된다. 동적 시작점 결정기의 하드웨어는 고속 동작에 적합한 단순한 구조로 도출된다. 제안된 방식의 성능 평가를 위해 다양한 트래픽에 대한 모의 실험 결과가 제공된다.

• 조명전기설비학회논문지
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• 제13권2호
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• pp.88-94
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• 1999

이 논문은 염가형 마이크로프로세서를 사용한 고효율 인버터 안정기에 관해서 기술한다. 인버터 안정기내의 고속의 스위칭 주파수로 인한 심각한 스위칭 손실과 EMI문제를 위해서 소프트-스위칭 기술을 제안한다. 또, 주위온도에 따라 형광 램프의 점등특성을 개선시키기 위한 온도검출 회로와 기동접압 제어회로, 역률개선, 램프의 수명연장 및 스위칭손실경감을 위한 소프트 스위칭 회로의 채용은 형광램프용 안정기로서 매혹적인 특성을 제공한다. 본 연구에서는 이상과 같은 특성개선을 위한 인버터 안정기의 동작과 제어방법을 자세히 제시하고, 이를 입증하기 위한 실험을 했다. 실험결과, 입력전류의 낮은 종합 고조파 왜율(4.8%)과 램프전류의 높은 역률(98%) 및 $-40^{\circ}C$에서도 기동이 원활한 우수한 특성을 얻을 수 있다.

• 대한두개안면성형외과학회지
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• 제21권6호
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• pp.376-379
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• 2020

Supraclavicular lymph node (SCLN) flap is a common donor site for vascularized lymph node transfer for the treatment of lymphedema. Chyle leakage is a rare but serious complication after harvesting SCLN flap in the neck. We report a case of chyle leakage at the SCLN donor site and its successful management. A 52-year-old woman underwent SCLN transfer for treatment of lower extremity lymphedema. After starting a regular diet and wheelchair ambulation on the 3rd postoperative day, the amount of drainage at the donor site increased (8-62 mL/day) with the color becoming milky, which suggested a chyle leak. Despite starting a low-fat diet on the 4th postoperative day, the chyle leakage persisted (70 mL/day). The patient was started on fat-free diet on the 5th postoperative day. The amount of drainage started to decrease and the drain color became more clear within 24 hours. The drainage amount remained less than 10 mL/day from the 8th postoperative day, and we removed the drain on the 12th postoperative day. There was no seroma or other wound complications at follow-up 4 weeks after the operation. The current case demonstrates that a fat-free diet can be a first-line treatment for low output chyle leakage after a SCLN flap.

• 대한방사선기술학회지:방사선기술과학
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• 제41권6호
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• pp.617-626
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• 2018

This study aims to provide the basic data helpful for the improvement of rights and interests of radiological technologists, by understanding the current working environment and if they get the proper reward through the analysis on the perception of appropriateness of current wage and job satisfaction of radiological technologists. Survey was conducted to evaluate the perception of satisfaction with job and wage system, work intensity, necessity of the radiological technologist limit system, and turnover in accordance. The appropriate starting salary was low in case of women and non-capital area, and when the age, academic background, career, and hospital size were lower. The appropriate wage was low in case of women and non-capital area, and when the academic background and hospital size were lower. The negative perception of the necessity to change the wage system was shown in university hospitals. Regarding the work intensity, in case of women and low career, and when the age, academic background, and hospital size were higher, the work intensity was perceived as high. When the academic degree and hospital size were lower, the positive perception of the radiological technologist limit was shown. The turnover intention was high in case of women, and when the age, academic background, career, and hospital size were lower. In order to increase the job satisfaction of radiological technologists, it would be necessary to the appropriate reward and the environment where they could concentrate on work.

• 한국정밀공학회지
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• 제25권9호
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• pp.53-58
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• 2008

The traditional engine valve train in a combustion engine is the mechanically driven camshaft system that provides one-fixed valve timing. The variable valve timing (VVT), however, is highly required to achieve the significant improvement in fuel economy. To achieve VVT in combustion engine, the solenoid type of actuator had been developed in past years, but it requires current in all operation period, the starting is difficult and the efficiency is low. In this paper, a new linear actuator using permanent magnet (PM) is proposed and verified its feasibility by finite element (FE) analysis.