• International Journal of Precision Engineering and Manufacturing
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• v.5 no.3
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• pp.69-76
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• 2004

Polishing a die that has free-form surfaces is a time-consuming and tedious job, and requires a considerable amount of high-precision skill. In order to reduce the polishing time and cope with the shortage of skilled workers, an automatic polishing robot system was developed. The polishing robot system is composed of two subsystems, a three-axis machining center and a two-axis polishing head. The machining center is controlled by a FANUC controller, and the polishing head by DSP controller. The system has five degrees of freedom and is able to keep the polishing tool normal to the die surface during operation. To easily operate the developed polishing robot system, this study developed an integrated operating program in the Windows environment. The program consists of five modules: a polishing data generation module, a code separation module, a polishing module, a graphic simulator module, and a teaching module. Also, the automatic teaching system was developed to easily obtain teaching data and it consists of a three dimensional joystick and a proximity sensor. Also, to evaluate the performance of the integrated operating program and the polishing robot system, polishing experiments of a die of shadow mask were carried out.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.123-123
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• 2000

Polishing a die that has free-form surfaces is a time-consuming and tedious job, and requires a considerable amount of high-precision skill. In order to reduce the polishing time and cope with the shortage of skilled workers, a user-friendly automatic polishing system was developed in this research. The polishing system with five degrees of freedom is able to keep the polishing tool normal to the die surface. The polishing system is controlled by a PC-NC controller. And, to easily onerate the developed polishing system, this stud)r developed a integrated program in the Windows environment. This program consists of 4 modules: polishing module, a graphic simulator, a polishing data generation module, and a teaching. Also, the automatic teaching system was developed to easily obtain a teaching data. The developed teaching system consists of a three dimensional joystick and a proximity sensor. In order to evaluate stability of the driving program and the leaching system, polishing experiments of the die of saddle shape were carried out.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.92-102
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• 2003

To detect electrical faults of a TFT (Thin Film Transistor) panel for the LCD (Liquid Crystal Display), techniques of converting electric field to an image are used One of them is the PDLC (polymer-dispersed liquid crystal) modulator which changes light transmittance under electric field. The advantage of PDLC modulator in the electric field detection is that it can be used without physically contacting the TFT panel surface. Specific pattern signals are applied to the data and gate electrodes of the panel to charge the pixel electrodes and the image sensor detects the change of transmittance of PDLC positioned in proximity distance above the pixel electrodes. The image represents the status of electric field reflected on the PDLC so that the characteristic of the PDLC itself plays an important role to accurately quantify the defects of TFT panel. In this paper, the image of the PDLC modulator caused by the change of electric field of the pixel electrodes on the TFT panel is acquired and how the characteristics of PDLC reflect the change of electric field to the image is analyzed. When the holding time of PDLC is short, better contrast of electric field image can be obtained by changing the instance of applying the driving voltage to the PDLC.

• Progress in Superconductivity
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• v.9 no.2
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• pp.162-166
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• 2008

We are developing a sensitive gamma ray spectrometer based on superconducting transition edge sensors. The detector consists of a small piece of high purity Sn as an absorber and a Ti/Au bilayer as a temperature sensor. It is designed to measure the thermal signal caused by absorption of gamma rays. The mechanical support and the thermal contact between the absorber and the thermometer were made with Stycast epoxy. The bilayer was formed by e-beam evaporation and patterned by wet etching on top of a $SiN_X$ membrane. A sharp superconducting transition of the film was measured near 100 mK. When the film was biased to the edge of the transition, signals were observed due to single photon absorption emitted from an $^{241}Am$ source. The measured spectrum showed several characteristic peaks of the source including 59.5 keV gamma line. The full with at half maximum was about 900 eV for the 59.5 keV gamma line. The background was low enough to resolve low energy lines. Considerations to improve the energy resolution of the gamma ray spectrometer are also discussed.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.315-318
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• 2015

2015년 3월 설문조사에 따르면 한국 직장인의 80%가 운동의 필요성을 인지하고 있을 만큼 건강과 탄탄한 몸매를 위한 사람들의 운동에 대한 관심이 빠르게 증가하고 있다. 지속적인 운동에 대한 관심이 증대되면서 스마트 디바이스를 활용한 운동 관련 애플리케이션 역시 증가하고 있다. 운동 기록을 측정하기 어렵고 별도의 장비가 필요하던 과거와는 달리, 이제는 누구나 가지고 있는 스마트폰만으로도 자신의 운동을 효율적으로 관리 할 수 있도록 하는 애플리케이션이 인기를 끌고 있다. 이러한 수요에 맞추어 스마트폰 상의 근접센서를 이용한 근력운동 측정 및 관리 시스템 '몸매가 예뻐 Gym'은 별다른 장비의 필요 없이 스마트폰에 기본적으로 내장되어 있는 근접센서를 이용하여 사용자에게 운동 기록 측정, 칼로리 소모량, 운동 일정 및 알림 기능을 제공한다. 특히, 기존의 다른 애플리케이션과 달리 상체, 복부, 하체의 신체 전체 운동을 한 시스템에서 제공하고, 챌린지 형식의 추천운동을 제공하여 애플리케이션에 게이밍 요소를 가미한 것이 특징적이다.

• Structural Monitoring and Maintenance
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• v.6 no.1
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• pp.33-46
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• 2019

In present study, Operational Modal Analysis (OMA) was employed to carry out the dynamic and vibration analysis of the threshing unit of the combine harvester thresher as a mechanical component. The main study is to find the causes of vibration and to decrease it to enhance the lifetime and efficiency of the threshing unit. By utilizing OMA, structural modal parameters such as mode shapes, natural frequencies, and damping ratio was calculated. The combine harvester was excited by engine to vibrate different parts and accelerometer sensor collected acceleration signals at different speeds, and OMA was utilized by nonparametric and frequency analysis methods to obtain modal parameters while vibrating in real working conditions. Afterwards, finite element model was designed from the thresher and updated using the data obtained from the modal analysis. Using the conducted analyses, it was specified that proximity of the thresher pass frequency to one of the natural frequencies (16.64 Hz) was the most important effect of vibration in the thresher. Modification process of the structure was carried out by increasing mass required for changing the natural frequency location of the first mode to 12.4 Hz in order to reduce resonance and vibration of the thresher.

• Journal of Sensor Science and Technology
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• v.31 no.4
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• pp.238-243
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• 2022

In this study, a pyrene-core single molecule with amino (-NH₂) functional group material was hybridized using ZnO quantum dots (QDs). The suppressed performance of the 1-aminopyrene (1-PyNH₂) single molecule as an emissive layer (EML) in light-emitting diodes (LEDs) was exploited by adopting the ZnO@1-PyNH₂ core-shell structure. Unlike pristine 1-PyNH₂ molecules, the ZnO@1-PyNH₂ hybrid QDs formed energy proximity levels that enabled charge transfer. This result can be interpreted as an improvement in surface roughness. The uniform and homogeneous EML alleviates dark-spot degradation. Moreover, LEDs with the ITO/PEDOT:PSS/TFB/EML/TPBi/LiF/Al configuration were fabricated to evaluate the performance of two emissive materials, where pristine-1-PyNH₂ molecules and ZnO@1-PyNH₂ QDs were used as the EML materials to verify the improvement in electrical characteristics. The ZnO@1-PyNH₂ LEDs exhibited blue luminescence at 443 nm (FWHM = 49 nm), with a turn-on voltage of 4 V, maximum luminance of 1500 cd/m², maximum luminous efficiency of 0.66 cd/A, and power efficiency of 0.41 lm/W.

• International journal of advanced smart convergence
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• v.11 no.2
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• pp.7-12
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• 2022

Safety and security are the topmost priority in every environment. With the aid of Artificial Intelligence (AI), many objects are becoming more intelligent, conscious, and curious of their surroundings. The recent scientific breakthroughs in autonomous vehicular designs and development; powered by AI, network of sensors and the rapid increase of Internet of Things (IoTs) could be utilized in maintaining safety and security in our environments. AI based on deep learning architectures and models, such as Deep Neural Networks (DNNs), is being applied worldwide in the automotive design fields like computer vision, natural language processing, sensor fusion, object recognition and autonomous driving projects. These features are well known for their identification, detective and tracking abilities. With the embedment of sensors, cameras, GPS, RADAR, LIDAR, and on-board computers in many of these autonomous vehicles being developed, these vehicles can properly map their positions and proximity to everything around them. In this paper, we explored in detail several ways in which these enormous features embedded in these autonomous vehicles, such as the network of sensors fusion, computer vision and natural image processing, natural language processing, and activity aware capabilities of these automobiles, could be tapped and utilized in safeguarding our lives and environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.10
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• pp.902-909
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• 2015

In this paper, monovision based relative navigation for a satellite proximity operation is studied. The chaser satellite only uses one camera sensor to observe the target satellite and conducts image tracking to obtain the target pose information. However, by using only mono-vision, it is hard to get the depth information which is related to the relative distance to the target. In order to resolve the well-known difficulty in computing the depth information with the use of a single camera, the active contour method is adopted for the image tracking process. The active contour method provides the size of target image, which can be utilized to indirectly calculate the relative distance between the chaser and the target. 3D virtual reality is used in order to model the space environment where two satellites make relative motion and produce the virtual camera images. The unscented Kalman filter is used for the chaser satellite to estimate the relative position of the target in the process of glideslope approaching. Closed-loop simulations are conducted to analyze the performance of the relative navigation with the active contour method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.627-633
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• 2020

Assembly process data can be gathered in real time in a manufacturing execution system (MES) server using proximity sensors, barcodes, RFID, ZigBee, Bluetooth, wireless sensor networks, etc. Although this is suitable for identifying process flow and checking production progress, it is difficult to trace the location of individual workers in real time for missing work or trajectories within the work area. To overcome this, the location and trajectory of the working tool can be analyzed in real time through a position tracking system of an operator's working tool. It can instruct the operator to perform a consistent working process. Productivity and quality improvement can be achieved by an alarming or blocking operator with possible assembly defects during the assembly process in real time. To this end, we developed a real-time tool position-tracking sensor system based on Ultra Wide Band (UWB) trilateration using a Kalman filter to eliminate mechanical vibration and radio communication noise.