• Transactions on Electrical and Electronic Materials
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• v.12 no.6
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• pp.262-266
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• 2011

A simulation study of a current-mode direct current (DC)-DC boost converter is presented in this paper. This converter, with a fully-integrated power module, is implemented by using bipolar complementary metal-oxide semiconductor (BiCMOS) technology. The current-sensing circuit has an op-amp to achieve high accuracy. With the sense metal-oxide semiconductor field-effect transistor (MOSFET) in the current sensor, the sensed inductor current with the internal ramp signal can be used for feedback control. In addition, BiCMOS technology is applied to the converter, for accurate current sensing and low power consumption. The DC-DC converter is designed with a standard 0.35 ${\mu}m$ BiCMOS process. The off-chip inductor-capacitor (LC) filter is operated with an inductance of 1 mH and a capacitance of 12.5 nF. Simulation results show the high performance of the current-sensing circuit and the validity of the BiCMOS converter. The output voltage is found to be 4.1 V with a ripple ratio of 1.5% at the duty ratio of 0.3. The sensing current is measured to be within 1 mA and follows to fit the order of the aspect ratio, between sensing and power FET.

• Nuclear Engineering and Technology
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• v.43 no.6
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• pp.567-572
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• 2011

A sensitivity analysis of the methods used to evaluate the transport properties of a CdZnTe detector was performed using two different radiations (${\alpha}$ particle and gamma-ray) emitted from an $^{241}Am$ source. The mobility-lifetime products of the electron-hole pair in a planar CZT detector ($5{\times}5{\times}2\;mm^3$) were determined by fitting the peak position as a function of biased voltage data to the Hecht equation. To verify the accuracy of these products derived from ${\alpha}$ particles and low-energy gamma-rays, an energy spectrum considering the transport property of the CZT detector was simulated through a combination of the deposited energy and the charge collection efficiency at a specific position. It was found that the shaping time of the amplifier module significantly affects the determination of the (${\mu}{\tau}$) products; the ${\alpha}$ particle method was stabilized with an increase in the shaping time and was less sensitive to this change compared to when the gamma-ray method was used. In the case of the simulated energy spectrum with transport properties evaluated by the ${\alpha}$ particle method, the peak position and tail were slightly different from the measured result, whereas the energy spectrum derived from the low-energy gamma-ray was in good agreement with the experimental results. From these results, it was confirmed that low-energy gamma-rays are more useful when seeking to obtain the transport properties of carriers than ${\alpha}$ particles because the methods that use gamma-rays are less influenced by the surface condition of the CZT detector. Furthermore, the analysis system employed in this study, which was configured by a combination of Monte Carlo simulation and the Hecht model, is expected to be highly applicable to the study of the characteristics of CZT detectors.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.499-502
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• 2009

Supply of electric power and electricity safety for whole system and network are essential element. Electricity safety technology need rating for product and research about certification as product development that is done cotton flannel mixed with development of u-IT technology consists. Study on serve to develop electricity safety integration supervision system to apply product to u-City electric power appliance and cotton flannel mixed of u-IT appliance, Connection badness sensing instrument made device built-in electric power IT cotton flannel mixed in outlet that is used most in electric power appliance terminal. Using sensor on ZigBee, RFID performance estimation of communication and module for remote safety check of electricity safety integration supervision system. A performance experiment and estimation in PD, Arc detection diagnosis system and certification KS, electricity safety about product that get fitness finding.

• Journal of the Korea Convergence Society
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• v.12 no.7
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• pp.263-271
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• 2021

Optoelectronic shooting training systems are used in shooting training sites to improve the accuracy of shooting by tracking the trajectories of gun movements. However, optoelectronic-based systems have limitations in terms of cost, complexity of installation, and the risk that electronic targets may be broken. In this study, we developed and verified a shooting training system that measures postural tremors using a low-cost accelerometer. The acceleration sensor module was designed to be attached to the air cylinder of a gun. Postural tremors were evaluated based on amplitude, frequency, and spatial pattern index, which were computed using acceleration data. The postural tremor indices between the accelerometer and optoelectronic-based system were highly correlated (left-right and up-down directions: r = 0.76 and r = 0.70, respectively). We validated the developed shooting training system using an independent two-sample t-test, which identified a significant difference (p < 0.05) in the calculated postural tremor index according to the athlete's shooting score (i.e., best and worst shots).

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1411-1416
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• 2018

Currently, most of the industrial areas like chemistry, manufacturing, shipbuilding, and steel, perform the work related to gas, and the staffs who are in charge of this work have a risk of suffocation without cognizing incidents like gas leak. For example, when the nitrogen gas leaked in 2015 at Paju, two people were killed and four people were injured. In 2018 at Pohang, four workers were suffocated to death from nitrogen gas. In order to solve this problem, this study realized the system in which workers could immediately cognize the gas leak and also deliver the situation to the staff in charge of safety at the same time, by installing the IoT device composed of gas sensor and communication module on the safety helmet that should be worn by field workers. This study is expected to be able to reduce the casualties caused by gas leak in industrial sites.

• International journal of advanced smart convergence
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• v.7 no.4
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• pp.50-56
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• 2018

The Internet of Things (IoT) and Visible Light Communication (VLC) is opening up new services in lighting industry by integrating sensory network features in addition to standard illumination functionality. In this progressive developments, the next generation lighting devices for smart homes are capable to sense the environmental conditions and transfer the captured data through lights to gateway controller to access remotely. The smart home environmental sensor information's are few kbps only so VLC systems need to built-in with low rate light connectivity to transfer data to the gateway. To provide error free communication, the quality of a received light signal is important to be considered when designing an VLC receiver. Therefore, this paper proposes the design of robust low rate IoL receiver design using NCP302 voltage detector for micro controller to adapt the IoT/IoL front end module for system integration. To evaluate the proposed system performance, the Arduino UNO based IoT/IoL controller designed with lighting, sensors and lights connectivity interfaces. The experimental result shows that the robust interference rejection is feasible on proposed VOL receiver and possible to have an error-free communication up to 10 kbps at a low SNR using OOK modulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.83-90
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• 2018

LoRa (Long Range) is a long-distance, low-power communication technology. Broader range of communication than NFC technology allows communication without having to install multiple APs and reduces the cost of initial infrastructure deployment. MQTT (Message, Queuing, Telemetry, Transport) protocol is also low power and lightweight protocols. It can increase module persistence and reduce maintenance costs when used with LoRa. In this paper, we developed a system for compiling various environmental information in a factory using LoRa and MQTT. Environmental sensor data from long distances can be monitored by the management system and the facilities in each workshop can be controlled. Performance tests have also shown that the use of LoRa and MQTT is effective in terms of long-distance and power consumption.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.942-943
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• 2016

Stereo gamma ray detection system generates a two-dimensional image of the gamma ray by using the position values and the gamma ray signal. And the device will overlap with the visible light image shows the actual distribution of the gamma-ray space. The gamma ray detection device is a stereo configuration to a motion controller for controlling the signal measurement unit and the position detection portion for detecting the detection portion and the gamma-ray signal comprising a gamma-ray detection sensor. In this paper, we developed a system operation management algorithm for each module individually configured efficiently. We confirmed the imaged and distribution information output for the gamma rays from gamma-ray irradiation test site by using these results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.219-224
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• 2019

The number of solar power installation companies including domestic small scale (50kW or less) is increasing rapidly, but the efficient operation system and management are insufficient. Therefore, a new type of operating system is needed as a maintenance management aspect to maximize the generation amount in the current state rather than the additional function which causes the increase of the generation cost. In this paper, we utilize Big Data and sensor network to maximize the operating efficiency of solar power plant and analyze the expert system to develop power generation prediction technology, module unit fault detection technology, life prediction of inverter components and report technology, maintenance optimization And to develop a smart monitoring system that enables optimal operation of photovoltaic power plants such as development of algorithms and economic analysis.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.2
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• pp.67-73
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• 2018

There are many types of power facilities such as transformers, switches, and energy storage devices in the micro grid environment. However, with the development of IoT technology, opportunities to acquire sensor information such as temperature, pressure, and humidity are provided. In the existing micro grid environment, the communication protocols such as MMS transport protocol in IEC 61850 standard is applied in accordance with the integrated operation between the power facilities and the platform. Therefore, to accommodate IoT data, a gateway technology that can link IoT data to a data collection device (FEP) based on IEC 61850 is required. In this paper, we propose IEC 61850 based IoT gateway platform prototype for microgrid operating system linkage. The gateway platform consists of an IoT protocol interface module (MQTT, CoAP, AMQP) and database, IEC 61850 server. For databases, We used open source based NoSQL databases, Hbase and MongoDB, to store JSON data. We verified the interoperability between the IoT protocol and the IEC 61850 protocol using Sisco's MMS EASY Lite.