• 한국항행학회논문지
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• 제15권6호
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• pp.1111-1117
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• 2011

본 연구에서는 의료용 신조명 부품으로 주목받고 있는 고출력 LED를 사용해 구강구조 확인을 위한 치과영역, 진료 및 수술실에서 환부에 대한 작은 범위(국소부위)의 무영 촬영이 가능한 휴대용 LED Light를 설계 개발하였다. 개발에 적용한 LED는 피사체 고유의 Tone에 대한 섬세한 표현력과 입체감을 부각시키기 위해 다양한 색상 구현 및 광량조절이 가능하도록 3색 LED를 사용했다. 사용된 LED의 전기적 특성 및 광학적 특성을 고려해 고효율의 Light Module를 개발했으며 휴대 사용을 위해 낮은 전압에서도 구동이 가능한 SMPS를 제작했다. 또한 PWM 제어방식을 이용해 단색광부터 백색광까지 32,768개의 다양한 색상 구현이 가능했다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권10호
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• pp.3729-3749
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• 2021

At present, deep convolution network-based salient object detection (SOD) has achieved impressive performance. However, it is still a challenging problem to make full use of the multi-scale information of the extracted features and which appropriate feature fusion method is adopted to process feature mapping. In this paper, we propose a new adjacency auxiliary network (AANet) based on multi-scale feature fusion for SOD. Firstly, we design the parallel connection feature enhancement module (PFEM) for each layer of feature extraction, which improves the feature density by connecting different dilated convolution branches in parallel, and add channel attention flow to fully extract the context information of features. Then the adjacent layer features with close degree of abstraction but different characteristic properties are fused through the adjacent auxiliary module (AAM) to eliminate the ambiguity and noise of the features. Besides, in order to refine the features effectively to get more accurate object boundaries, we design adjacency decoder (AAM_D) based on adjacency auxiliary module (AAM), which concatenates the features of adjacent layers, extracts their spatial attention, and then combines them with the output of AAM. The outputs of AAM_D features with semantic information and spatial detail obtained from each feature are used as salient prediction maps for multi-level feature joint supervising. Experiment results on six benchmark SOD datasets demonstrate that the proposed method outperforms similar previous methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권7호
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• pp.2131-2153
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• 2022

To achieve accurate detection of tuberculosis (TB) areas in chest radiographs, we design a chest X-ray TB area detection algorithm. The algorithm consists of two stages: the chest X-ray TB classification network (CXTCNet) and the chest X-ray TB area detection network (CXTDNet). CXTCNet is used to judge the presence or absence of TB areas in chest X-ray images, thereby excluding the influence of other lung diseases on the detection of TB areas. It can reduce false positives in the detection network and improve the accuracy of detection results. In CXTCNet, we propose a channel attention mechanism (CAM) module and combine it with DenseNet. This module enables the network to learn more spatial and channel features information about chest X-ray images, thereby improving network performance. CXTDNet is a design based on a sparse object detection algorithm (Sparse R-CNN). A group of fixed learnable proposal boxes and learnable proposal features are using for classification and location. The predictions of the algorithm are output directly without non-maximal suppression post-processing. Furthermore, we use CLAHE to reduce image noise and improve image quality for data preprocessing. Experiments on dataset TBX11K show that the accuracy of the proposed CXTCNet is up to 99.10%, which is better than most current TB classification algorithms. Finally, our proposed chest X-ray TB detection algorithm could achieve AP of 45.35% and AP50 of 74.20%. We also establish a chest X-ray TB dataset with 304 sheets. And experiments on this dataset showed that the accuracy of the diagnosis was comparable to that of radiologists. We hope that our proposed algorithm and established dataset will advance the field of TB detection.

• 한국태양에너지학회 논문집
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• 제35권5호
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• pp.57-65
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• 2015

The Potential Induced Degradation(PID) in PV module mainly affected by various performance conditions such as a potential difference between solar cell and frame, ambient temperature and relative humidity. The positive charges as sodium ions in front glass reach solar cell in module by a potential difference and are accumulated in the solar cell. The ions accelerate the recombination of generation electrons within solar cell under illumination, which reduces the entire output of module. Recently, it was generally known that PID generation is suppressed by controlling the thickness of SiNx AR coating layer on solar cell or using Sodium-free glass and high resistivity encapsulant. However, recovery effects for module with PID are required, because those methods permanently prevent generating PID of module. PID recovery method that voltage reversely applies between solar cell and frame contract to PID generation begins to receive attention. In this paper, PID recovery tests by using voltage under various outdoor conditions as humidity, temperature, voltage are conducted to effectively mitigate PID in module. We confirm that this recovery method perfectly eliminates PID of solar cell according to repeative PID generation and recovery as well as the applied voltage of three factors mainly affect PID recovery.

• 한국기계가공학회지
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• 제15권4호
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• pp.125-133
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• 2016

From the first application of a thermoelectric module to nowtoday, it has been more than half a century. The application of a thermoelectric module is becoming more and more widely accepted since, people's requirement rely more and more on the efficiency of thermoelectric modules and their reliability become higher and higher. So people pay more and more attention to the thermoelectric module. In Around the world, the more research for into improving the efficiency of thermoelectric modules is focused on the current materials. at present. However, the research of into available materials had has some limitations, and the research of materials had reached a bottleneckthere are limits to current applications. On the other hand, from the production process, if we assembled by materials withoutmodules without any damages and achieve the ideal state of a joint, we can make the a product to maximize performance and have a longer service life. SoTherefore, in this study we will prove the relationship between the any defects inside and the efficiency of a thermoelectric module to improve the quality management and performance of modern thermoelectric modules at present.

• 한국정보통신학회논문지
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• 제22권1호
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• pp.140-146
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• 2018

최근 실내조명으로 사용하는 LED(Light Emitting Diode)와 무선통신 기술을 융합한 가시광통신이 주목받고 있다. 하지만 가시광 통신은 광 신호를 측정할 수 있는 커버리지 내에서만 통신이 가능하고, 비가시선 영역에서 통신이 단절되는 현상이 발생한다. 본 논문에서는 가시광 통신의 커버리지 확장과 비가시선 영역에서 통신 단절 현상 개선을 위해 VLC(Visible Light Communication) 릴레이 모듈을 제안한다. 제안하는 VLC 릴레이 모듈은 송신기로부터 전달받은 패킷을 VLC 릴레이 모듈 및 수신기로 전송한다. 1개의 VLC 송신기와 3개의 VLC 릴레이 모듈을 설치하여 실험을 진행하였으며, VLC 릴레이 모듈의 증가에 따른 통신 커버리지 확장과 비가시선 영역에서 통신 단절 현상 개선을 확인하였다. 또한, 이중 샘플링 기법을 사용하여 광 신호 측정 성능이 2.4배 향상됨을 확인하였다.

• 한국포장학회지
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• 제29권3호
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• pp.223-228
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• 2023

Sustainable energy supplies without the recharging and replacement of the charge storage device have become increasingly important. Among various energy harvesters, the triboelectric nanogenerator (TENG) has attracted considerable attention due to its high instantaneous output power, broad selection of available materials, eco-friendly and inexpensive fabrication process, and various working modes customized for target applications. In this study, the amount of voltage and current generated was measured by applying the PSD profile random vibration test of the electronic vibration tester and ISTA 3A according to the time of Anodized Aluminum Oxide (AAO) pore widening of the manufactured TENG device Teflon and AAO. The discharge and charging tests of the integrated module during the random simulated transport environment and the recognition distance of RFID were measured while agricultural products (onion) were loaded into the returnable folding plastic box. As a result, it was found that AAO alumina etching processing time to maximize TENG performance was optimal at 31 min in terms of voltage and current generation, and the integrated module applied with the TENG module showed a charging effect even during the continuous use of RFID, so the voltage was kept constant without discharge. In addition, the RFID recognition distance of the integrated module was measured as a maximum of 1.4 m. Therefore, it was found that the surface condition of AAO, a TENG element, has a great influence on the power generation of the integrated module, and due to the characteristics of TENG, the power generation increases as the surface dries, so it is judged that the power generation can be increased if the surface drying treatment (ozone treatment, etc.) of AAO is applied in the future.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 추계학술대회
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• pp.44-45
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• 2011

Research on photovoltaic (PV) generation is taking a lot of attention due to its infinity and environment-friendliness with decrease of price per PV cell. While central inverters connect group of PV modules to utility grid in which maximum power point tracking (MPPT) for each module is difficult, micro inverter is attached on each module so that MPPT for individual modules can be easily achieved. Moreover, energy generation and consumption efficiency can be much improved by employing direct current (DC) distribution system. In this paper, a digitally controlled PV micro converter interfacing PV to DC distribution system is proposed. Boundary conduction mode (BCM) is utilized to achieve zero voltage switching (ZVS) of active switch and eliminate reverse recovery problem of passive switch. A 120W prototype boost PV micro converter is implemented to verify the feasibility and experimental results show higher than 98% efficiency at peak power and 97.29% of European efficiency.

• Journal of Power Electronics
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• 제14권6호
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• pp.1281-1292
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• 2014

Photovoltaic (PV) solar systems with series-connected module integrated converters (MICs) are receiving increased attention because of their ability to create high output voltage while performing local maximum power point tracking (MPPT) control for individual solar panels, which is a solution for partial shading effects in PV systems at panel level. To eliminate the partial shading effects in PV system more effectively, sub-MICs are utilized at the cell level or grouped cell level within a PV solar panel. This study presents the results of a series-output-connection MPPT (SOC-MPPT) controller for sub-MIC architecture using a single sensor at the output and a single digital MPPT controller (sub-MIC SOC-MPPT controller and architecture). The sub-MIC SOC-MPPT controller and architecture are investigated based on boost type sub-MICs. Experimental results under steady-state and transient conditions are presented to verify the performance of the controller and the effectiveness of the architecture.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.609-610
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• 2006

As developing the information society, Lighting Emitted diode(LED) which is light source for illumination of next generation is attracted public attention. LED have many problem as narrow light view angle, high price, drift phenomenon of color coordinate, high heating problem for lower power, lower weight and small size. So, many researches have continued in a illumination as LED module type. in this problem, heating problem is very important and difficult and that is caused in decreasing phenomenon of brightness and drift phenomenon of color coordinate. so the problem of heating is urgent question for illumination of LED. In this paper, structural design of PCB changed as two type for solving the heating problem. also the properties of heating is analysed and optical properties is measured with heating image camera and spectrometer according to change in this design.