• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.60-67
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• 2011

A photovoltaic/thermal(PVT)solar system is the solar technology that allows for simultaneous conversion of solar energy into both electricity and heat. This paper compared the performance of PVT system with a conventional PV module and solar collector and analyzed electrical and thermal efficiency of PVT system in terms of solar irradiance and inlet temperature of the working fluid. Based on the experimental data, thermal and electrical efficiencies of the glazed PVT system were 57.9% and 14.27% under zero reduced temperature condition which were lower by 13.6% than the solar thermal absorber plate and by 0.08% than the PV module respectively. For the unglazed PVT system, it had lower thermal efficiency than the solar thermal absorber plate but higher electrical performance than the PV module due to the cooling effect by the working fluid. However, total efficiency of the glazed PVT system was 72.2% which was higher than combined efficiencies of the solar collector and PV module. Besides, total efficiency of the PVT system would be much higher if calculated based on unit area.

• Transactions of Materials Processing
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• v.7 no.3
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• pp.246-259
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• 1998

This paper describes a research work of developing a computer-aided design and manufacturing of irregular shaped sheet metal product for blanking or piercing and bending operations. An approach to the system is based on the knowledge-based rules. Knowledge for the system is formulated from plasticity theories experimental results and the empirical knowledge of field experts, This system has been written in AutoLISp on the AutoCAD and in customer tool kit on the SmartCAM with a personal computer and is composed of nine modules which are input and shape treatment, flat pattern-layout, pro-processor module. Based on the knowledge-based rules, the system is designed by considering several factors, such as material and thickness of product complexities of blank geometry and punch profile sheet metal to give flat pattern and automatically account for the adjustment of bending allowances to match tooling requirements by checking dimensions and generating NC data automatically according to drawings of die-layout module. Results carried out in each module will provide efficiencies to the designer and the manufacturer of blanking or piercing and bending die in this field.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.133-136
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• 2019

Recently, many industrial devices are facing protocol compatibility problems with external monitoring and control systems. This paper designed an industrial communication gateway that can support the transformation of industrial communication protocol using multi-layered communication module. Industrial communication gateways have a structure that connects individual communication modules using rs485 serial communication to multiple layers. Each communication module consisted of analog data card, a digital data card LAN, and a CAN-enabled card. The main board processor used Atmega micro-processor, and the rs485 serial slot was placed to have a multi-layer communication module structure. These additive layer type communication modules support analog and digital I/O functions and LAN and CAN for wide use in industrial communication control and monitoring.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1313-1315
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• 1996

This paper presents a new method to obtain more stable and precise A/D conversion for remote sensing use. Hardware is designed to compensate offset voltage and drift & temperature characteristics, as well as to perform dual slop A/D converter by using single chip microprocessor. Serial communication program which is based on ASCII code commands is also developed to add initial setup & calibration functions as well as to perform A/D data communication. Proposed method will give a good applications to the industrial field where a high precision remote sensing is required.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.274-277
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• 1996

This paper describes the realization of the full-color to the degree of nearest white light by compounding high brightness Red, Green and Blue LEDs with appropriate proportional index. Once these three colors; red, green and blue are mixed, they are genearlly additive mixing and produce white light color contrasted to negative mixing. The luminous efficiency is defined as the product of the efficiency(lm/w), which indicates the degree of perceptual response by the human eye to unit energy(W) of light emitted by an active display devises and as the conversion efficiency of the device from electric power consumed to optical energy produced. We will deduce the each number of LEDs theoretically and design several shapes of LED displays for the full-color. Finally theoretical predictions will be compared with the measured data with different type of display designs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.139-140
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• 2010

This paper presents an indoor prototype for wireless digital signal transmission using Visible Light Communications (VLC) in which high power Light Emitting Diode (LED) is used. Using low cost and off-the-shelf components, the transmitter module is constructed using an AVR Atmega128 microcontroller and commercial white beam LEDs. Modulating the light intensity of the LED enables digital signals to be transmitted across the optical link. The receiver module employs a high speed PIN photodetector for optical signal detection and a recovery circuit for optical-electro signal conversion. By sending digitalized data via VLC technology, many applications can be realized in the areas of consumer advertising, traffic safety information and disaster control.

• The KIPS Transactions:PartD
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• v.11D no.2
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• pp.485-494
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• 2004

Recently, the wireless internet terminals like mobile phones or PDAs prevail in the management of customers. With such terminals, businessmen can get business data and information of customers in real time, in connection with mobile group wares. By the wireless terminals, customers can conveniently get information of goods, search purchase sites, and give orders and do settlement. This paper aims to present the safe data integrity modules of the wireless internet terminal, for service providing correct real-time promotion information, by using users' disposition, situation, Purchase information. This study aims to suggest an implementation methodology of security module for data integrity of mobile internet terminal. This is based on the WTLS of WAP Protocol. This security module is expected to achieve central role in conversion of wireless internet environment and emphasis of encryption technology and safe and calculable wireless communication environment construction

• Journal of Korea Multimedia Society
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• v.25 no.11
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• pp.1557-1563
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• 2022

Currently Spatial Data is collected and processed in various methods, and its usability is very high. However, the existing Spatial Data analysis Software usually requires professional knowledge in the collection, refinement, and application of spatial Date, making it difficult to access and apply it. Therefore, this study established a new WebGIS platform with improved accessibility and usability to solve these problems. This platform supports various services such as master map sharing, spatial data generation, automatic coordinate system conversion, WMS issuance, grid generation, and grid analysis. These services increase operational convenience, such as simplifying repetitive tasks and automatically expressing text files. While it is believed that non-experts can easily and conveniently because of them to simplify and express the results. In addition, it is judged to have high accuracy and reliability compared to the analysis results using the existing Open Source-based GIS software.

• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.123-131
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• 2009

In this paper, we design ZigBee RF based framework for mobile web service on collected data by sensor node and transmitting data to data base by sensor network and remote sensing server through wireless connection. The proposed system is an integrated platform of sensor network for the sensor management and providing SOA based sensor web access. This paper combines SOA technology with sensor network. composes sensor node as web view, and provides high capability. extensiveness, reliability, and usability to the user who accesses to sensor web. The mobile message conversion module, SOAP message processing module. WSDL message generator, and mobile web service module is embodied for improving the capacity of the framework. The capacity evaluation of local wireless communication system which is proposed in this paper is analyzed through NS-2 simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.371-375
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• 2013

A new model about output power prediction of PV module with various tilted angles and cell to cell distances has been proposed in this paper. Light intensity arrived on a solar cell could be changed by characteristics of PV module materials. Refractive indices, thickness and absorption coefficients of glass, EVA, solar cell and Backsheet are used to predict output. Also, the incident angle of light is changed 0 to 90[$^{\circ}$] and cell to cell distances are 5, 10 15[mm]. Two types of light incident on a solar cell are considered which are direct to a solar cell and reflected from Backsheet. The intensity of the incident light directly into the solar cell is reduced through glass and EVA about 17.5[%] in theoretical way. It has an error of 2.26[%] compared with experimental result. The results for compare theoretical with experimental data is validated within the error of 6.3[%]. This paper would be a research material to predict output power when the PV module is installed outdoor or a building.