• Journal of Power Electronics
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• v.15 no.4
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• pp.929-938
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• 2015

Maximum power point tracking (MPPT) and battery charging control are two important functions for a solar battery charger. The former improves utilization of the available solar energy, while the latter ensures a prolonged battery life. Nevertheless, complete implementation of both functions can be complex and costly, especially for low voltage application such as standalone street lamps. In this paper, the operation of a solar battery charger for standalone street light systems is investigated. Using only one voltage sensor, the solar charger is able to operate in both MPPT and constant voltage (CV) charging mode, hence providing high performance at a low cost. Using a lab prototype and a solar simulator, the operation of the charger system is demonstrated and its performance under varying irradiance is validated.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_1
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• pp.545-551
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• 2023

In this paper, a robot automation methodology for chemical drum assembly in semiconductor industries are presented. Robot automation is essential to resolve safety issues in which operators are directly or indirectly exposed to chemicals or fumes in assembling dispense heads on chemical drums. However, the chemical drum assembling process involves complex and difficult tasks, such as mating male/female keycodes and fastening screws with large-diameter, which may be very difficult to be performed by a single-arm robot with a commercial rigid F/T sensor. In order to solve the problems, a method for assembling a chemical drum using dual-arm collaborative robot system, compliance F/T sensor, robot vision and gripper is presented.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1257-1260
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• 1996

This paper describes a fully digitalized driver for BLDC motors and the driver is realized by a single chip microprocessor. The speed change can be done by using the signal obtained from the position detecting sensor and adjusting the pulse width at the input channel of power module. In order to verify the effectiveness, an repetitive control method is adopted in the speed control tracking a periodic reference change in the BLDC motor system. The experimental results are shown for the reference tracking accurately according to the design parameter variation in the repetitive controller design.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.928-934
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• 1998

This paper describes a fully digitalized driver for BLDC motors which is realized by a single chip microprocessor. The speed change can be done by using the signal obtained from the position detecting sensor and adjusting the pulse width at the input channel of power module. In order to establish a speed control system a repetitive control method is adopted to track a periodic refer-ence change in the BLDC motor system. The experimental results show accurate reference track-ing performance under the given periodic reference in the repetitive controller design.

• Journal of the Korean Society of Radiology
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• v.13 no.1
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• pp.39-44
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• 2019

Radiation safety management is being considered very important since radioactive isotopes such as Co-60 and Ir-192 are widely used in fields such as non-destructive test(NDT). In this study, the applicability of Mercury(II) Iodide($HgI_2$) source for tracing system was evaluated. To make sure the unit cell sensor's reliability, we evaluated the electrical properties of the sensor made with $HgI_2$, and then position dependence of the sensor was analyzed and compared with the dose distribution from the planning system. As a result of the evaluation, high reliability of the sensor was shown through the linearity of R-sq > 0.990 and reproducibility of CV < 0.015. In the position dependence evaluation, the maximum value was measured at the isocenter of the sensor and gradually decreased according to the distance. However, the dose distribution data from the planning system was turned out that has difference with that of the sensor up to 30%. This seems to come from the difference between single-point measuring based planning system and area measuring based sensor.

• Journal of Platform Technology
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• v.11 no.6
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• pp.106-115
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• 2023

In this paper, we propose a sensor data sharing system for the safe and smooth operation of autonomous vehicles on two-way single lanes in traffic-isolated areas and implement the core module, the situational awareness technology. Two-way single lanes pose challenges for autonomous vehicles, particularly when encountering parked vehicles or oncoming traffic, leading to reversing issues. We introduce a system using infrastructure cameras to detect vehicles' approach, enter, and leave on twoway single lanes in real-time, transmitting this information to autonomous vehicles via V2N communication, thereby expanding the sensing range of the autonomous vehicles. The core part of the proposed system is the situational awareness of the two-way single lane using infrastructure cameras. In this paper, we implement this using object detection and tracking technology. Finally, we validate the implemented situational awareness technology using data collected from actual two-way single lanes.

• The KIPS Transactions:PartA
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• v.14A no.7
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• pp.399-408
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• 2007

Currently various techniques for efficiently developing sensor network applications are developed. However, these techniques provide the method for developing only single sensor network application easily and rapidly. Since sensor network applications control various sensor nodes based on core components of operating system, the technique to develop applications by defining common functionalities of various applications and selecting variable functionalities according to the work flow of specific application is efficient. Accordingly, this paper presents an experimental study that identifies commonality of sensor network application domain and supports optional development according to the variability of application by applying product line approach to developing sensor network application. Through the experimental study, we describe the characteristics of sensor network application domain compared with general business domain for product line development. Also, we show the effectiveness of the proposed approach by presenting that core assets designed using the proposed variability feature model and VEADL are reused according to the functionalities of each sensor node.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1100-1109
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• 2006

In this study, two different technologies which can measure temperature simultaneously at many points are introduced. One is to use a thermal sensor cable that is comprised of addressable thermal sensors connected in parallel within a single cable. The other is to use an optic fiber with Distributed Temperature Sensing (DTS) system. The difference between two technologies can be summarized as follows. A thermal sensor cable has a concept of 'point sensing' that can measure temperature at accurate position of a thermal sensor. So the accuracy and resolution of temperature measurement are up to the ability of the thermal sensor. Whereas optic fiber sensor has a concept of 'distributed sensing' because temperature is measured by ratio of Stokes and anti-Stokes component intensities of Raman backscatter that is generated when laser pulse travels along an optic fiber. It's resolution is determined by measuring distance, measuring time and spatial resolution. The purpose of this study is that application targets of two temperature measurement techniques are checked in technical and economical phases by examining the strength and weakness of them. Considering the functions and characteristics of two techniques, the thermal sensor cable will be suitable to apply to the assessment of groundwater flow, geothermal distribution and grouting efficiency within 300m distance. It is expected that the optic fiber sensor can be widely utilized at various fields (for example: pipe line inspection, tunnel fire detection, power line monitoring etc.) which need an information of temperature distribution over relatively long distance.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.4
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• pp.357-362
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• 2012

Despite the Wave observations data is very important information to human life at sea, the technology development and research for wave equipments are lacking. In this study, the wave observation system using GPS was evaluated the quality of wave observation data by comparing of long-term observations. The result of the comparison of the acceleration sensor (Hippy-40) and GPS sensor (Mose-1000), the correlation coefficient of the significant wave height and significant wave periods is 0.997 and 0.990 respectively. Also in case of BIAS, the significant wave height is 0.014 m, the significant wave period is -0.212 sec. It makes no significant differences whether the acceleration sensor (Hippy-40) and GPS sensor (Mose-1000). These results of the wave observation data using GPS quality will be evaluated as very good.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.93-96
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• 2015

In this paper, we introduce a fire detection system using context-aware sensor. In existing weather and based on vision sensor of fire detection system case, acquired image through sensor of camera is extracting features about fire range as processing to convert HSI(Hue, Saturation, Intensity) model HSI which is color space can have durability in illumination changes. However, in this case, until a fire occurs wide range of sensing a fire in a single camera sensor, it is difficult to detect the occurrence of a fire. Additionally, the fire detection in complex situations as well as difficult to separate continuous boundary is set for the required area is difficult. In this paper, we propose an algorithm for real-time by using a temperature sensor, humidity, Co2, the flame presence information acquired and comparing the data based on multiple conditions, analyze and determine the weighting according to fire it. In addition, it is possible to differential management to intensive fire detection is required zone dividing the state of fire.