• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.844-847
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• 2007

전 세계적으로 환경에 대한 관심이 고조되는 가운데 각 산업에서의 환경보호를 위한 노력이 꾸준히 진행되고 있다. 건설분야에서도 환경보존 을 노력이 지속되고 있는 실정이다. 이에 본 논문에서는 친환경성, 고내구성, 가변성, 갱신성능 그리고 쾌적성 등의 종합적인 성능을 갖춤으로써 미래형 건축물의 기본요소가 될 수 있는 친환경 지능형 건축 Component system 제안을 위한 요소기술 분석에 초점을 맞추었다. 친환경 지능형 건축 Component system 개발을 위해 요구되는 성능을 파악한 후 그 성능을 구현시키기 위한 요소기술을 분석한 결과, SI주택과 Home Automation 기술이 주요 요소기술로 도출되었다. 그리고 이론 및 문헌 고찰을 통해 도출된 요소기술의 개념 및 개발동향에 대하여 대해 살펴본 후 최종적으로 이러한 기술요소의 융합을 통한 친환경 지능형 건축 Component system 을 제안하였다.

• Journal of Power Electronics
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• 제19권5호
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• pp.1303-1314
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• 2019

This paper studies the harmonic characteristics of ship electric propulsion systems and their treatment methods. It also adopts effective measures to suppress and prevent ship power systems from affecting ship operation due to the serious damage caused by harmonics. Firstly, the harmonic characteristics of a ship electric propulsion system are reviewed and discussed. Secondly, aiming at problems such as resonant frequency and filter characteristics variations, resonance point migration, and unstable filtering performances in conventional passive filters, a method for fully tuning of a passive dynamic tunable filter (PDTF) is proposed to realize harmonic suppression. Thirdly, to address the problems of the uncontrollable inductance L of traditional air gap iron core reactors and the harmonics of power electronic impedance converters (PEICs), this paper proposes an electromagnetic coupling reactor with impedance transformation and harmonic suppression characteristics (ECRITHS), with the internal filter (IF) designed to suppress the harmonics generated by PEICs. The ECRITHS is characterized by both harmonic suppression and impedance change. Fourthly, the ECRITHS is investigated. This investigation includes the harmonic suppression characteristics and impedance transformation characteristics of the ECRITHS at the fundamental frequency, which shows the good performance of the ECRITHS. Simulation and experimental evaluations of the PDTF are carried out. Multiple PDTFs can be configured to realize multi-order simultaneous dynamic filtering, and can effectively eliminate the current harmonics of ship electric propulsion systems. This is done to reduce the total harmonic distortion (THD) of the supply currents to well below the 5% limit imposed by the IEEE-519 standard. The PDTF also can eliminate harmonic currents in different geographic places by using a low voltage distribution system. Finally, a detailed discussion is presented, with challenges and future implications discussed. The research results are intended to effectively eliminate the harmonics of ship electric power propulsion systems and to improve the power quality of ship power systems. This is of theoretical and practical significance for improving the power quality and power savings of ship power systems.

• 한국지반환경공학회 논문집
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• 제20권3호
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• pp.15-20
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• 2019

확한 토공량 설계를 위해서는 충분한 량의 지반조사 자료가 필요하나 비용적인 문제로 인하여 제한적인 지반조사가 수행되고 있다. 정확한 토공량 예측을 위해서 지반의 층상정보를 추정하는 것은 중요한 사항이며, 이러한 제한적인 지반조사 데이터로부터 정확한 토공량 예측을 위해서는 지구통계학적(geo-statistical) 분석방법으로 지반 층상정보를 예측할 수 있다. 또한, 기시추된 지반 층상정보를 활용하여 기계학습을 통하여 모델을 학습하여 미시추된 지반 층상정보를 예측할 수도 있는데, 본 논문에서는 인공신경망을 통하여 미시추된 지반 층상정보를 예측하고 기존의 정규 크리깅 기법과 성능을 비교한다. 이를 위하여, 84공의 지반 층상정보를 활용한다. 84공의 지반 층상정보의 데이터셋 중에서 75공을 학습 데이터셋으로 활용하였고, 나머지 9공을 검증 데이터셋으로 활용하였다. 검증 데이터셋의 실측된 지반 층상정보와 정규 크리깅 기법과 인공신경망으로 예측된 지반 층상정보를 비교 분석한다.

• 한국정보통신학회논문지
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• 제25권11호
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• pp.1670-1675
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• 2021

건설산업 영역의 스마트 건설 기술 도입이 빠르게 진행되고 있다. BIM(Building Information Modeling), 드론, 인공지능, 빅데이터, 사물인터넷 기술 등 스마트 건설 기술을 활용하여 시공 현장의 재해율을 낮추고 시공 기간을 단축시키는 효과를 가져온다. 건설 시공 현장 관리를 위한 디지털 트윈 플랫폼을 도입하기 위해서는 실제 시공 현장을 가상의 공간과 동일하게 구축하여 실시간으로 현장 관리를 가능하게 한다. 디지털 트윈 가상공간 구축방법은 시공 전주기 데이터를 수집 및 가공을 하고 3D 모델 파일을 이용하여 시각화 한다. 본 논문에서는 디지털 트윈 공간을 구성하는 3D 모델링을 3차원 공간 데이터를 기반으로 자동생성하여 효율적인 디지털 트윈 공간을 구축하는 모델링 자동화 기법을 소개한다.

• 접착 및 계면
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• 제6권1호
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• pp.1-6
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• 2005

The high accurate simulation of very thin glue layers based on the finite element method is still connected to many problems which result from the necessity to construct a complicated mesh of essentially different sizes of elements. This can lead to a loss of accuracy, unstable calculations and even loss of convergence. However, the implementation of special transmission elements along the glue ling and special edge-elements in the near-edge region would lead to a dramatic decrease of number of finite elements in the mesh and thus, prevent unsatisfactory phenomena in numerical analysis and extensive computation time. The theoretical basis for such special elements is the knowledge about appropriate transmission conditions and the edge effects near the free boundary of the adhesive layer. Therefore, recently proposed so-called non-classical transmission conditions and the behavior near the free edge are investigated in the context of the single-lap tensile-shear test of adhesive technology.

• Journal of Power Electronics
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• 제15권5호
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• pp.1207-1216
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• 2015

In order to suppress the low frequency oscillation of the neutral-point voltage for three-level inverters, this paper proposes a new discontinuous pulse width modulation (DPWM) control method. The conventional sinusoidal pulse width modulation (SPWM) control has no effect on balancing the neutral-point voltage. Based on the basic control principle of DPWM, the relationship between the reference space voltage vector and the neutral-point current is analyzed. The proposed method suppresses the low frequency oscillation of the neutral-point voltage by keeping the switches of a certain phase no switching in one carrier cycle. So the operating time of the positive and negative small vectors is equal. Comparing with the conventional SPWM control method, the proposed DPWM control method suppresses the low frequency oscillation of the neutral-point voltage, decreases the output waveform harmonics, and increases both the output waveform quality and the system efficiency. An experiment has been realized by a neutral-point clamped (NPC) three-level inverter prototype based on STM32F407-CPLD. The experimental results verify the correctness of the theoretical analysis and the effectiveness of the proposed DPWM method.

• 센서학회지
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• 제27권2호
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• pp.99-104
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• 2018

A micro electromagnetic actuator with high vibration efficiency is proposed for use in an implantable hearing device. The actuator, which can be implanted in the middle ear, consists of membranes based on the stainless steel 304 (SUS-304), and other components. In conventional actuators, in which a thick membrane and a silicone elastomer are used, the size reduction was difficult. In order to miniaturize the size of the actuator, it is necessary to reduce the size of the actuation potion that generates the driving force, resulting in reduction of the electromagnetic force. In this paper, the electromagnetic actuator is further miniaturized by the metal membrane and the vibration amplitude is also optimized. The actuator designed according to the simulation results was fabricated by using micro-electro-mechanical systems (MEMS) technology. In particular, a $20{\mu}m$ thick metal membrane was fabricated using the erosion process, which reduced the length of the actuator by more than $400{\mu}m$. In the experiments, the vibration displacement characteristics of the optimized actuator were above 400 nm within the range of 0.1 to 1 kHz when a current of $1mA_{rms}$ was applied to the coil.

• 대한기계학회논문집A
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• 제21권3호
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• pp.430-438
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• 1997

Deburring and edge finishing technology as the final process of machining operation is required for manufacturing of advanced precise conponents. But, deburring is considered as a difficult problem on going to the high efficient production and automation in the FMS. Removal of burr couldn't have a standard of its definition because of its various shapes, dimensions and properties and mostly depends on manual treatment. Especially, deburring for cross hole inside is very difficult owing to its shape passing through out perpendicular to a main hole. The electrochemical method is suggested as its solution in practical aspect. Therefore, electrochemical deburring technology needs to be developed for the high efficiency and automation of internal deburring in the cross hole. In this study, the new process in the eliminating burr inside cross hole, electrochemical deburring by the wheel electroplated with Cubic-Boron-Nitrade abrasives, is suggested. Its deburring mechanism is described and machining performances is investigated. Also, CBN electroplated wheel is designed and manufactured and then characteristics of electrochemical deburring are investigated through experiments. Overall electrochemical deburring performance against burr inside cross hole is examined in the various power sources such as peak current and direct current.

• 한국세라믹학회지
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• 제48권4호
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• pp.316-322
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• 2011

Tin oxide thin films were deposited by rf reactive sputtering and annealed at $400^{\circ}C$ for 1 h in vacuum. To minimize the influence such as reduction, oxidation, and doping on tin oxide thin films during annealing, a vacuum ambient annealing was adopted. The structural, optical, and electrical properties of tin oxide thin films were characterized by X-ray diffraction, atomic force microscope, UV-Vis spectrometer, and Hall effect measurements. After vacuum annealing, the grain size of all thin films was slightly increased and the roughness ($R_a$) was improved, however irregular and coalesced shapes were observed from the most of the films. These irregular and coalesced crystal shapes and the possible elimination of intrinsic defects might have caused a decrease in both carrier concentration and mobility, which degrades electrical conductivity.

• 한국산업융합학회 논문집
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• 제19권1호
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• pp.42-49
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• 2016

This study proposes a non-contact inspective technology based robot vision system for Faulty Inspection of welding States and Parts Shape. The maine focus is real time implementation of the machining parts' automatic inspection by the robotic moving. For this purpose, the automatic test instrument inspects the precision components designator the vision system. pattern Recognition Technologies and Precision Components for vision inspection technology and precision machining of precision parts including the status and appearance distinguish between good and bad. To perform a realization of a real-time automation integration system for the precision parts of manufacturing process, it is designed a robot vision system for the integrated system controller and verified the reliability through experiments. The main contents of this paper, the robot vision technology for noncontact inspection of precision components and machinery parts is useful technology for FA.