• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.277-290
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• 2019

The demand for indoor positioning is increasing day by day. However, the widely used positioning methods today cannot satisfy the requirements of the indoor environment in terms of the positioning accuracy and deployment cost. In the existing research domain, the localization algorithm based on three-dimensional space is less accurate, and its robustness is not high. Visible light communication technology (VLC) combines lighting and positioning to reduce the cost of equipment deployment and improve the positioning accuracy. Further, it has become a popular research topic for telecommunication and positioning in the indoor environment. This paper proposes a surface centroid TOA localization algorithm based on the VLC system. The algorithm uses the multiple solutions estimated by the trilateration method to form the intersecting planes of the spheres. Then, it centers the centroid of the surface area as the position of the unknown node. Simulation results show that compared with the traditional TOA positioning algorithm, the average positioning error of the surface centroid TOA algorithm is reduced by 0.3243 cm and the positioning accuracy is improved by 45%. Therefore, the proposed algorithm has better positioning accuracy than the traditional TOA positioning algorithm, and has certain application value.

• Journal of Space Technology and Applications
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• v.4 no.2
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• pp.87-104
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• 2024

CubeSats are being utilized in various fields such as Earth observation, space exploration, and verification of space science and technology due to their low cost, short development period, enhanced mission-oriented performance, and ability to perform various missions through constellation and formation flights. Recently, as the availability of CubeSats has increased and their application areas have expanded, the demand for high-speed transmission of large amounts of data obtained by CubeSats has increased unprecedentedly. Laser-based free space optical communication technology is capable of transmitting large amounts of data at high speeds compared to the existing radio communication methods, and provides various advantages such as use of unlicensed spectrum, low cost, low power, high security characteristics, and of use a small communication platform. For this reason, it is suitable as a high-performance communication technology to support CubeSat missions. In this paper, we will present the core components and characteristics of CubeSat-based space laser communication system, and recent research trends, as well as representative technology development results.

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.7-11
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• 2012

SiNx films have been wildly used as anti-reflection coatings and passivation for crystalline silicon solar cells. In this study, the SiNx films were deposited by using high frequency (13.56MHz) PECVD and optical & passivation properties were investigated. The RF power was changed in a certain range for the film deposition. Then, the refractive index, etch rate, minority carrier lifetime and cell efficiency were measured to study the properties of the film respectively. The optimal deposition conditions for application to crystalline silicon solar cells were proposed as results of the study. Finally, the best cell efficiency of 16.98% was obtained from the solar cell with the SiNx films deposited by RF power of 550W.

• Annual Conference on Human and Language Technology
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• 2013.10a
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• pp.82-85
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• 2013

개체명 인식기에 대한 연구에서 개체명 사전은 필수적으로 필요하다. 그러나 공개된 개체명 사전은 거의 없기 때문에, 본 논문에서는 디비피디아의 데이터로부터 개체명을 효과적으로 추출하여 자동으로 구축할 수 있는 방법을 제안한다. 제안 방법은 엔트리의 '이름'과 '분류' 정보를 사용한다. 엔트리의 '이름'은 개체명으로 사용하고, 엔트리의 '분류'는 각 개체명 클래스와의 상호정보량을 계산하여 엔트리와 개체명 클래스 사이의 점수를 계산한다. 이렇게 계산된 점수를 이용하여 개체명과 개체명 클래스를 매핑한다. 그 결과 76.7%의 평균 정확률을 보였다.

• Journal of the Semiconductor & Display Technology
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• v.14 no.3
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• pp.23-26
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• 2015

A seam carving based micro-crack detection method is proposed which aims at detecting the micro-crack regions in heterogeneously textured surface of polycrystalline solar cells. By calculating the seam which is a connected path of low energy pixels in the image, the micro-crack regions can be detected. Experimental results show that the proposed seam carving based micro-crack detection method has superior efficiency in detecting the micro-crack without background noise pixels and the algorithm's computation time is less than the conventional algorithm.

• International Journal of Knowledge Content Development & Technology
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• v.12 no.3
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• pp.19-29
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• 2022

The new age is characterised by information communication technology, where computers, laptops, mobile gadgets such as palmtops, tablets, mobile phones and the internet have made their way to every sphere of life from our domestic environments such a homes, small retail shops, banks to large industries and the world at large. Over time, so many questions about the ethical use of Information and Communication Technology (ICT) have emerged on who has access to what technology and the use of it and like every other technological invention. This paper will look at the morality involved in making use of ICT to promote ethical use of data or information in a virtual environment. ICT also possesses both positive and negative impacts; the questions that these impacts raise are what this piece attempts to answer, providing global scrutiny to these ethical issues, situations and questions; and providing recommendations in line with global best practices.

• International Journal of Knowledge Content Development & Technology
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• v.14 no.2
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• pp.7-27
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• 2024

This study examines the use of electronic databases (e-databases) by faculty members of the Ghana Communication Technology University (GCTU). The study used a descriptive research method. Copies of the questionnaire were used for the data collection. Due to the manageable population, no sampling method was used in this study. The Statistical Package for the Social Sciences (IBM-SPSS 21.0) was used for data analysis. The results showed that most faculty members were aware of the availability of databases in the library. Additionally, the findings established that Emerald, as well as Taylor and Francis, were ranked highly in terms of availability and accessibility. The study identified problems such as difficulty in downloading information as well as poor internet connectivity. Based on the results, the study recommended that library management should address all the challenges that users encounter as soon as possible.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.456-467
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• 2016

Wireless Access in Vehicular Environments (WAVE) communication technology, which provides vehicleto-vehicle and vehicle-to-infrastructure communication and offers safe and convenient service, has been developed for application to an Intelligent Transport System (ITS). This paper provides field test results on a study of the feasibility of WAVE technology application to railway communication systems. A test railway communication system based on WAVE technology has been built along the Daebul line and a newly developed EMU. Field tests have been carried out according to the communication function requirements for LTE - R. The test results show that the railway communication system based on WAVE technology meets the functional requirements: maximum transmission length is 730m, maximum transfer delay is 5.69ms, and maximum interruption time is 1.36s; other tests including throughput test, video data transmission test, VoIP data test, and channel switching test also produced results that meets the functional requirements. These results suggest that WAVE technology can be applied to the railway communication system, enabling Vehicle-to-Wayside communication.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.1-8
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• 2013

Wireless Visible Light Communication is the technology that enables communication using LED illumination Infrastructure instead of existing illumination such as incandescent lamp or fluorescent light. Because VLC uses light for communication, it has no problem of frequency permission and is harmless to human body. It is also possible to check the communication through eye. So VLC can be used as a supplement to the Radio Frequency communication, Infrared in indoor environment. So far, researchers on the LED Visible light communication have focused on the increasing transmission speed, transmission distance, modulation method. However, there is few research of main factors that influence on system performance. System performance has been mainly predicted through simulation. In this paper, I recognized that these factors such as outside light noise, obstacle, LED panel position or emitted angle have a great impact on wireless communication system. So I experimented VLC system by changing distance and position to discover location suitable for BER regulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.187-194
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• 2012

Vehicular communication networking is one of the most important building blocks of Intelligent Transportation System(ITS). The vehicular communication network is a wireless communication system enabling vehicles to communicate with each other as well as with roadside base stations. Especially, Wi-Fi based vehicle-to-infrastructure(V2I) communication is an emerging solution to improve the safety, traffic efficiency, and comfort of passengers. In this paper, we proposed a new communication hub platform for vehicles, and explained vehicle communication technology in short. Through car simulation results, we show thar our proposed system reduces signaling interference.