• 동력기계공학회지
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• 제20권3호
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• pp.22-28
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• 2016

Energy consumption rapidly increases with industrial development. therefore an interest in the efficiency of various power converters is increasing. Especially, the field of high-efficiency small motors widely distributed for industrial and family use is considered a very important field in terms of efficient energy usage, and accordingly, in the field of small electric equipment, the use of BLDC that allows high-efficiency drive in an inductor gradually increases. However, for the BLDC drive, information on the position of the rotor is essential. Both methods using a magnetic encoder and an optical encoder to detect the information on the position of the rotor obtain the information by three position sensitive devices, and if any one of these position sensitive devices fails to function, no positional information can be obtained, so there is a limitation in implementing a position sensor with high reliability. In the paper, proposes a new type of encoder that can obtain the positional information on the position of the rotor using a single position sensor in order to overcome the issues that it has to use numerous signal flows and that the reliability is reduced for the acquisition of positional information generated by using multiple position detectors. The encoder in the proposed method replaced the function of generating positional information from multiple sensors with the shape of the encoder plate and the capture function of MICOM. In order to verify the validity of the position detection technique by the proposed encoder, a prototype was produced, and an experiment using the capture function of DSP was conducted through this.

• 전자공학회논문지SC
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• 제49권2호
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• pp.38-45
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• 2012

선천성 난청으로 태어난 아이를 조기에 진단하여 가능한 빨리 적절한 치료를 해줌으로써 치료 효과를 극대화하고, 이후에 발생되는 사회적 비용을 최소화할 수 있기 때문에 신생아로부터 난청 이상 유무를 객관적으로 판별하는 검사 장비가 필요하다. 대표적인 것으로 청성뇌간반응(auditory brainstem response, ABR) 검사가 있으나 클릭음(click sound)에 대한 반응으로 주파수 특이성이 없고 고주파수 대역에 대한 청력을 주로 반영하는 단점이 있다. 청성지속반응(auditory steady-state response, ASSR) 검사는 주파수 특이도는 좋으나 오진의 가능성이 조금 높다. 이러한 단점을 보완하여 청성뇌간반응 검사와 청성지속반응 검사를 하나의 시스템에서 측정하고, Fsp와 F-test 분석을 통하여 객관적 지표를 보여주는 시스템을 제안하였다. 하드웨어 구성요소를 최소화하고 소프트웨어 역할을 강화하여 추후 하드웨어 수정 없이 소프트웨어의 수정만으로 다양한 검사가 가능하도록 설계하였다. 제안한 시스템의 객관적 평가 기능은 정상인 10명을 대상으로 한 실험을 통하여 검증하였다.

• 동력기계공학회지
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• 제9권4호
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• pp.96-101
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• 2005

Magnesium alloys have been widely used for many structural components of automobiles and aircraft because of high specific strength and good cast ability in spite of hexagonal closed-packed crystal structure of pure magnesium. In this study, uniaxial tension tests at high temperature and creep tests are done in order to investigate the characteristics of high temperature and mechanisms for creep deformation of AZ31 Mg alloy. Yield stress and ultimate tensile stress decreased with increasing temperature, but elongation increased from results of uniaxial tension test at high temperature. The apparent activation energy Qc, the applied stress exponent n and rupture life have been determined during creep of AZ31 Mg alloy over the temperature range of 473K to 573K and stress range of 23.42 MPa to 93.59 MPa, respectively, in order to investigate the creep behavior. Constant load creep tests were carried out in the equipment including automatic temperature controller, whose data are sent to computer. At around the temperature of $473K{\sim}493K$ and under the stress level of $62.43{\sim}93.59%MPa$, and again at around the temperature of $553K{\sim}573K$ and under the stress level of $23.42{\sim}39.00MPa$, the creep behavior obeyed a simple power-law relating steady state creep rate to applied stress and the activation energy for the creep deformation was nearly equal, respectively, and a little low to that of the self diffusion of Mg alloy including aluminum. Also rupture surfaces at high temperature have had bigger dimples than those at lower temperature by SEM.

• 한국측량학회지
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• 제38권3호
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• pp.269-279
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• 2020

교통량 산정은 주로 교통량조사시스템, 차량검지시스템, 통행료징수시스템 등과 같은 조사 장비와 CCTV를 통한 인력 조사를 병행하고 있으나 이는 많은 인력과 비용이 발생한다. 본 연구에서는 단일 CCTV의 경우 전체 차량을 탐지하지 못하는 한계를 극복하기 위해서, 딥러닝과 스테레오 CCTV를 이용하여 교통량을 산정하는 방법을 제안하였다. 차량을 탐지하기 위한 딥러닝 모델을 학습하기 위해 COCO 데이터셋을 사용하고, 실시간으로 좌우 CCTV 영상에서 각각 차량을 탐지하였다. 그리고 나서, 각 영상에서 추출하지 못한 차량을 부등각사상변환을 이용하여 추가적으로 차량을 탐지하여 교통량 산정의 정확도를 개선하였다. 실험은 평상시 도로 환경과 안개가 발생한 기상 상황의 경우에 대해서 각각 수행하였다. 평상시 도로 환경의 경우 단일 CCTV 영상을 사용할 때보다 좌우 영상에서 각각 6.75%, 5.92%의 차량 탐지의 개선효과가 있었다. 또한, 안개가 발생한 도로 환경의 경우 좌우 영상에서 각각 10.79%, 12.88%의 차량 탐지의 개선효과가 있었다.

• 한국비블리아학회지
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• 제6권1호
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• pp.179-213
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• 1984

The history of recording and conserving for maintenance the human's memory from ancient times to modern's has brought about a lot of changing process of the recorded information media with developing in culture, and each society has made important recorded materials in his library as essentially the social apparatus. But most of them that were damaged by factors of the natural disaster, humidity, temperature, light, fungi and insects in the library, and were resulted in deterioration and losing the numerous materials. For removing the inevitable phases repeated, there are studying for counterplan of the fundamental environment factors about preservation, restoration and chemical research of materials in advanced countries, but I get a few researches about protecting the cultural properties. Therefore I research the survey of the actual conditions on 72 university libraries centering around them, and then I have researched the collection rate 81 percent, 58 university libraries. (local : 35, in seoul : 23) As the result of this research, I propose the model of the environment factors of conserving the library materials. 1) To apply the equipment of processing the radiant energy to the new construction and buildings. 2) To remove factors that occur fungi and insects by facilities being controlled relative humility, temperature, and to equip the ventilation arrangement in the library. 3) To shelve all acquired and bound materials after proceeding the vacuum fumigator. 4) Those who want to enter into the library stack were surely taken in sterilzing their hands and shoes, and must put on the gown. 5) To use the vacuum dusting thing (machine) for removing the dust without spreading out the floor of the library at any time. 6) To set up the gas automatic fire extinguisher worked by smoke sensor. 7) To assist the research into the preservation, natures and environment of recorded materials, and to supply financial funds for librarian. 8) To hold regularly the workshop be able to educate the methods of preservation materials by the constant system. (Library Association) 9) To add to responsibilities on certification of preservation materials for librarian. 10) To hold the constant committee system in each library. 11) To keep up with the ideal environment (humidity, temperature, light, ventilation, etc.) of preservation materials in the arrangement room, and to put on the gown.

• 전기학회논문지
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• 제66권7호
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• pp.1039-1046
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• 2017

Campus microgrid is designed and built by considering not only power generation but also power consumption management as connected microgrid type because the main goal of the campus microgrid is to save power consumption costs. There are many functions to achieve the goal and they are mainly to use generation-based functions such as islanding operation for peak management and for emergency events. In power distribution operation, Conservation Voltage Reduction (CVR) is applied in order to reduce power consumption. The CVR is defined as a function for load consumption reduction by voltage reduction in order to reduce peak demands and energy consumption. However, application of CVR to microgrid is difficult because the microgrid cannot control a tap of transformer in a substation and the microgrid normally is not designed with phase modifying equipment like a step-voltage-regulator which can control voltage in power distribution system operation. In addition, an impact of the CVR is depended on load characteristics such as a normal load, a rated power, and synchronous motors. Therefore, this paper proposes an application of CVR using linear voltage control based AVR in campus microgrid with power consumption reduction considering characteristics of load and component in the microgrid. The proposed system can be applied to each buildings by a configuration of power distribution cables; and the application results and CVR factor are presented in this paper.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.773-776
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• 2009

최근의 차량 산업은 차량 내 전자장비들을 하나로 묶을 수 있는 네트워크들이 발달되고, 이에 따라 각각의 네트워크간의 통신이 중요시 되고 있다. 현재 차량에 사용되고 있는 네트워크로는 CAN, LIN, MOST, FlexRay 등이 사용되고 있다. 여러 가지 네트워크들이 생겨나면서 네트워크를 이용한 여러 가지 응용들도 생겨나게 되었고, 이로 인해 운전자들도 좀 더 편리한 환경에서 차량을 운전하고자 하는 욕구가 많아지고 있다. 차량내의 다른 네트워크 환경을 하나의 통합된 환경으로 만들어주기 위한 게이트웨이 연구가 활발히 이루어진다면, 보다 많은 응용들이 개발될 것으로 예상된다. 본 논문에서는 주로 차량의 Body Train 쪽 제어에 사용되는 CAN bus 네트워크와 인포테인먼트 시스템을 제공해주는 MOST 네트워크간의 게이트웨이를 이용한다. 통신을 통해 CAN Node중의 하나인 차량속도를 MOST Navigation 으로 전송하여 차량이 터널에 진입하여 GPS 정보를 얻어올 수 없을 때도 차량의 현재 속도정보를 Gateway를 통해 Navigation으로 실시간으로 전송하는 기술을 이용하는 차량 자동 안전제어 시뮬레이션 시스템 설계하고 구현하고자 한다.

• 해양환경안전학회지
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• 제25권3호
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• pp.269-277
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• 2019

Since 2020, according to the International Convention for the Prevention of Pollution from Ships (MARPOL) amended in 2016, each Administration shall transfer the annual fuel consumption of its registered ships of 5,000 gross tonnage and above to the International Maritime Organization (IMO) after verifying them. The Administration needs stacks of materials, which must not be manipulated by ship companies, including the Engine log book and also bears an administrative burden to verify them by May every year. This study considers using the Automatic Identification System (AIS), mandatory navigational equipment, as an objective and efficient tool among several verification methods. Calculating fuel consumption using a ship's speed in AIS information based on the theory of a relationship between ship speed and fuel consumption was reported in several examples of relevant literature. After pre-filtering by excluding AIS records which had speed errors from the raw data of five domestic cargo vessels, fuel consumptions calculated using Excel software were compared to actual bunker consumptions presented by ship companies. The former consumptions ranged from 96 to 123 percent of the actual bunker consumptions. The difference between two consumptions could be narrowed to within 20 percent if the fuel consumptions for boilers were deducted from the actual bunker consumption. Although further study should be carried out for more accurate calculation methods depending on the burning efficiency of the engine, the propulsion efficiency of the ship, displacement and sea conditions, this method of calculating annual fuel consumption according to the difference between two consumptions is considered to be one of the most useful tools to verify bunker consumption.

• 산업경영시스템학회지
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• 제43권4호
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• pp.190-197
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• 2020

Recently there was an incident that military radars, coastal CCTVs and other surveillance equipment captured a small rubber boat smuggling a group of illegal immigrants into South Korea, but guards on duty failed to notice it until after they reached the shore and fled. After that, the detection of such vessels before it reach to the Korean shore has emerged as an important issue to be solved. In the fields of marine navigation, Automatic Identification System (AIS) is widely equipped in vessels, and the vessels incessantly transmits its position information. In this paper, we propose a method of automatically identifying abnormally behaving vessels with AIS using convolutional autoencoder (CAE). Vessel anomaly detection can be referred to as the process of detecting its trajectory that significantly deviated from the majority of the trajectories. In this method, the normal vessel trajectory is gridded as an image, and CAE are trained with images from historical normal vessel trajectories to reconstruct the input image. Features of normal trajectories are captured into weights in CAE. As a result, images of the trajectories of abnormal behaving vessels are poorly reconstructed and end up with large reconstruction errors. We show how correctly the model detects simulated abnormal trajectories shifted a few pixel from normal trajectories. Since the proposed model identifies abnormally behaving ships using actual AIS data, it is expected to contribute to the strengthening of security level when it is applied to various maritime surveillance systems.

• 드라이브 ㆍ 컨트롤
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• 제20권2호
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• pp.15-23
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• 2023

In this study, two-dimensional location of crops for auto weeding was detected using deep learning. To construct a dataset for soybean detection, an image-capturing system was developed using a mono camera and single-board computer and the system was mounted on a weeding robot to collect soybean images. A dataset was constructed by extracting RoI (region of interest) from the raw image and each sample was labeled with soybean and the background for classification learning. The deep learning model consisted of four convolutional layers and was trained with a weakly supervised learning method that can provide object localization only using image-level labeling. Localization of the soybean area can be visualized via CAM and the two-dimensional position of the soybean was estimated by clustering the pixels associated with the soybean area and transforming the pixel coordinates to world coordinates. The actual position, which is determined manually as pixel coordinates in the image was evaluated and performances were 6.6(X-axis), 5.1(Y-axis) and 1.2(X-axis), 2.2(Y-axis) for MSE and RMSE about world coordinates, respectively. From the results, we confirmed that the center position of the soybean area derived through deep learning was sufficient for use in automatic weeding systems.