• 마이크로전자및패키징학회지
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• 제30권4호
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• pp.1-7
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• 2023

임의의 3D 구조물을 제작할 수 있는 3D/4D 프린팅 기술의 능력은 프린트된 구조물 디자인에 높은 자유도를 제공합니다. 이와 같은 능력은 전자기기 및 바이오 의료 응용분야에 장치 소형화, 맞춤화, 그리고 개인화 추세에 영향을 주고 있습니다. 본 Review 논문에서는, 3D/4D 프린팅 기술을 통해 만들어진, 독특하고 특이한 특성을 가진 3D 프린트된 전자기기 및 바이오 의료 응용 분야의 최신 정보를 살펴봅니다. 구체적으로, 재활용 및 분해 가능한 전자기기, 메타물질 기반 압력 센서, fully 프린트된 휴대용 광검출기, 생체 적합 및 고강도를 가진 치아, 자연모사 마이크로니들, 그리고 3D 세포 배양 및 히스톨로지를 위한 형태 변형 가능한 튜브 어레이와 같은 신흥 영역들을 소개합니다.

• Journal of Information Processing Systems
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• 제18권2호
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• pp.223-234
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• 2022

The evaluation of the print quality of 3D printing has traditionally relied on manual work using dimensional measurements. However, the dimensional measurement method has an error value that depends on the person who measures it. Therefore, we propose the design of a new print quality measurement method that can be automatically measured using the field-of-view (FOV) model and the intersection over union (IoU) technique. First, the height information of the modeling is acquired from a camera; the output is measured by a sensor; and the images of the top and isometric views are acquired from the FOV model. The height information calculates the height ratio by calculating the percentage of modeling and output, and compares the 2D contour of the object on the image using the FOV model. The contour of the object is obtained from the image for 2D contour comparison and the IoU is calculated by comparing the areas of the contour regions. The accuracy of the automated measurement technique for determining, which derives the print quality value was calculated by averaging the IoU value corrected by the measurement error and the height ratio value.

• 센서학회지
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• 제29권3호
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• pp.201-204
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• 2020

In this study, we fabricated and evaluated graphene composite based 3D scaffolds and planar films. The hybrid composite was prepared by mixing a calculated amount of graphene nanopowder and polydimethylsiloxane in tetrahydrofuran solution. The hybrid composite is easy to manufacture into various forms using direct printing technology or a pressing method. A 3D scaffold structure was prepared at ambient temperature with a flow rate of 240 mm/min. The nozzle pressure was maintained at 350 kPa by adjusting the viscosity of the composite material. The planar film was prepared at different thicknesses using a roll-to-roll equipment. The prepared hybrid nanocomposites were evaluated to investigate their electrical properties according to temperature and mechanical deformation. The obtained results were consistent with each other. Therefore, it can be used effectively as sensors through shape definition.

• 센서학회지
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• 제32권5호
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• pp.290-294
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• 2023

Among various types of harmful gases, hydrogen sulfide is a strong toxic gas that is mainly generated during spillage and wastewater treatment at industrial sites. Hydrogen sulfide can irritate the conjunctiva even at low concentrations of less than 10 ppm, cause coughing, paralysis of smell and respiratory failure at a concentration of 100 ppm, and coma and permanent brain loss at concentrations above 1000 ppm. Therefore, rapid detection of hydrogen sulfide among harmful gases is extremely important for our safety, health, and comfortable living environment. Most hydrogen sulfide gas sensors that have been reported are electrical resistive metal oxide-based semiconductor gas sensors that are easy to manufacture and mass-produce and have the advantage of high sensitivity; however, they have low gas selectivity. In contrast, the electrochemical sensor measures the concentration of hydrogen sulfide using an electrochemical reaction between hydrogen sulfide, an electrode, and an electrolyte. Electrochemical sensors have various advantages, including sensitivity, selectivity, fast response time, and the ability to measure room temperature. However, most electrochemical hydrogen sulfide gas sensors depend on imports. Although domestic technologies and products exist, more research is required on their long-term stability and reliability. Therefore, this study includes the processes from electrode material synthesis to sensor fabrication and characteristic evaluation, and introduces the sensor structure design and material selection to improve the sensitivity and selectivity of the sensor. A sensor case was fabricated using a 3D printer, and an Ag reference electrode, and a Pt counter electrode were deposited and applied to a Polytetrafluoroethylene (PTFE) filter using PVD. The working electrode was also deposited on a PTFE filter using vacuum filtration, and an electrochemical hydrogen sulfide gas sensor capable of measuring concentrations as low as 0.6 ppm was developed.

• 디지털산업정보학회논문지
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• 제11권3호
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• pp.1-9
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• 2015

In this paper, we implemented the computer vision platform design with MEAN Stack through Raspberry PI 2 model which is an open source platform. we experimented the face recognition, temperature and humidity sensor data logging with WiFi communication under Raspberry Pi 2 model. Especially we directly made the shape of platform with 3D printing design. In this paper, we used the face recognition algorithm with OpenCV software through haarcascade feature extraction machine learning algorithm, and extended the functionality of wireless communication function ability with Bluetooth technology for the purpose of making Android Mobile devices interface. And therefore we implemented the functions of the vision platform for identifying the face recognition characteristics of scanning with PI camera with gathering the temperature and humidity sensor data under IoT environment. and made the vision platform with 3D printing technology. Especially we used MongoDB for developing the performance of vision platform because the MongoDB is more akin to working with objects in a programming language than what we know of as a database. Afterwards, we would enhance the performance of vision platform for clouding functionalities.

• 한국운동역학회지
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• 제31권3호
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• pp.183-188
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• 2021

Objective: The purpose of this study was to develop a stretchable joint motion sensor that is based on silver nano-particle. Through this sensor, it can be utilized as an equipment for rehabilitation and analyze joint movement. Method: In this study, precursor solution was created, after that, nozel printer (Musashi, Image master 350PC) was used to print on a circuit board. Sourcemeter (Keithley, Keithley-2450) was used in order to evaluate changes of electric resistance as the sensor stretches. In addition, the sensor was attached on center of a knee joint to 2 male adults, and performed knee flexion-extension in order to evaluate accurate analysis; 3 infrared cameras (100 Hz, Motion Master 100, Visol Inc., Korea) were also used to analyze three dimensional movement. Descriptive statistics were suggested for comparing each accuracy of measurement variables of joint motions with the sensor and 3D motions. Results: The change of electric resistance of the sensor indicated multiple of 30 times from initial value in 50% of elongation and the value of electric resistance were distinctively classified by following 10%, 20%, 30%, 40% of elongation respectively. Through using the sensor and 3D camera to analyze movement variable, it showed a resistance of 99% in a knee joint extension, whereas, it indicated about 80% in flexion phase. Conclusion: In this research, the stretchable joint motion sensor was created based on silver nanoparticle that has high conductivity. If the sensor stretches, the distance between nanoparticles recede which lead gradual disconnection of an electric circuit and to have increment of electric resistance. Through evaluating angle of knee joints with observation of sensor's electric resistance, it showed similar a result and propensity from 3D motion analysis. However, unstable electric resistance of the stretchable sensor was observed when it stretches to maximum length, or went through numerous joint movements. Therefore, the sensor need complement that requires stability when it comes to measuring motions in any condition.

• 사물인터넷융복합논문지
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• 제6권3호
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• pp.75-80
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• 2020

최근의 IoT 센서의 소형화와 센서의 소형화로 인하여 다른 센서 및 구조물들과의 간섭 및 견고성을 고려하여 더욱 복잡해 지고 있다. 최근 3D 프린팅 기술은 센서 직접 제작이나, 센서 소자를 포함하는 기구를 만드는 분야에 다양하게 적용이 되고 있다. 그 중에서, fused deposition modeling(FDM) 기술은 장비 및 소재의 가격이 상당히 저렴하며, IoT 기기의 제작이 활용이 가능한 가장 유력한 기술중에 하나이다. 그런 FDM 프린팅 기술은 플라스틱 소재 기반의 필라멘트를 녹여서 적층하여 3D 형상을 만들어 내는 기술이며, 최근에 특허 종료와 아울러 오픈 소스 기반의 저가형 프린터가 개발됨으로 일반인들에게도 널리 사용되고 있다. 이런 FDM 기술을 이용하여 출력된 출력물에 있어서 기계적 물성치는 소재의 종류와 다양한 공정 변수들에 의해서 영향을 받는다. 그 중에서도 내부 채움(infill)은 기계적 물성치에도 큰 영향을 주면, 출력 시간에도 영향을 준다. 따라서 본 논문에서 내부 채움과 기계적 물성치 및 출력 시간 사이의 관계를 규명하여, 기계 기구물을 제작할 때 출력 시간과 기계적 물성치를 고려한 최적의 내부 채움 조건 선정 방법을 제시하고자 한다. 제시된 방법을 증명하고자, 다른 공정은 모두 고정하고, 내부 채움 조건만을 변경한 인장 시편을 제작하고, 제작된 시편을 인장 실험을 통하여 내부 채움에 따른 출력물의 기계적 물성치를 비교 분석하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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• pp.1311-1320
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• 2016

The fourth industrial revolution is currently proceeding and is expected to significantly affect the way individuals live and in result change the society in various aspects. The ICT-based convergence industries of the fourth industrial revolution contain various fields such as driverless cars, lighter and tougher materials, robotics, 3D printing and even biotechnology. This paper examines the researches done in fourth industrial revolution field based on the articles submitted to APIC-IST 2015. The topics from articles related to the fourth industrial revolution were categorized based on the keyword frequency of main issues. Results suggested that IoT and Wireless sensor network related researches were among the fields that the most researches were done in it and topics like nanotechnology, biotechnology, driverless cars, sharing economy and 3D printing were not mentioned at all. This paper also suggests necessary contents in the fourth industrial revolution to be focused on for further research in this field.

• 융합정보논문지
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• 제10권10호
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• pp.47-52
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• 2020

일반적인 평판 프린터 시스템은 PC와 전용 S/W로 구성되어 사용에 불편함이 존재한다. 결국, 평판 프린터 시스템 구성의 간소화, 스마트화 등을 통해 다양한 형태의 프린팅을 쉽고 편리하게 사용할 수 있는 기술이 필요하다. 즉, 한 대의 프린터로 여러 종류의 소재에 인쇄가 가능하며, 다양한 형태의 상품을 인쇄할 수 있는 다입체 프린터에 대한 수요가 증가하고 있다. 따라서, 본 논문에서는 Head Encoder/Trigger 제어를 이용하여 다입체 인쇄가 가능한 평판 프린터 시스템을 개발하였다. 이를 위해, 평판 프린터 내부 모듈을 입력 형태 감지 센서를 연계시키고, 별도의 메인 콘트롤러를 통해 프린터의 Head Encoder와 Head Trigger 신호에 의해 모든 동작 상태를 제어하는 평판 프린터를 개발하였다. 이를 통해, IoT 기술의 발전 및 보급의 확산으로 산업 전반에 걸쳐 스마트 환경의 프린터 제어가 발전된 형태로 확대될 것이며, 향후 3D 프린팅 산업 발전에 기여할 것으로 기대된다.

• 한국기계가공학회지
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• 제19권10호
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• pp.111-116
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• 2020

Flexible tactile sensors, which are primarily used as grippers in robots, are mainly used to handle highly elastic or highly flexible objects. That is, flexible grippers are used when an object cannot be sufficiently controlled by applying a specific output force or taking a specific grabbing action. This is because a flexible tactile sensor needs to measure the pressure applied directly to held objects while deforming according to the shape of the object to be handled. CNT-based sensors used to be made from a highly flexible polymer to give flexibility and it is known that the sensors are greatly affected by the contact resistance of the terminal that connects the sensor to an electrical circuit; therefore, this paper clarifies the contact resistance of MWCNTs-based flexible tactile sensors and terminals. The effects of main and plating materials for terminals are investigated and the combinations of main and plating materials that exhibit contact resistance are measured in a typical industrial environment.