• Bulletin of the Korean Space Science Society
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• 2002.05b
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• pp.47.1-47
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• 2002

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.11-19
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• 2010

Technological development of information and communication have brought sharp changes to every sector such as society, culture, economy and education because of knowledge and information-oriented society. The number of classes has decreased, and some schools are closed or incorporated due to decrease of the population. Such phenomenon has brought changes to learning using digital technology and space. A change called digital innovation is characterized by interactive communication centering on the internet network. Therefore, it is very important to predict educational environment to be changed according to digital environment and to note how real learning space is changed. The development of digital technology in society in general presents two concepts of digital and contents, digitalized information. Such technology is recognized as a new paradigm in education sector and a new space is created through participation of instructors and learners in learning space. This study analysed cases of learning space of elementary schools based on bibliographical examination and related bibliography including data from academic presentations and news release to present developed leaning space. To present healthy and creative learning environment which can lead knowledge and information-based society in the future, the preface described the background, purpose, methods and range of the study, and analysed transitional processes of society and culture, digital learning contents, and learning space in education of elementary schools. Finally the study identified trends and cases of research on learning space and suggested digital learning contents space.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.39.3-40
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• 2020

For the space weather research, KASI (Korea Astronomy and Space Science Institute) is developing the SNIPE (Small-scale magNetospheric and Ionospheric Plasma Experiment) mission, which consists of four 6U CubeSats of ~10 kg. Besides of space weather research, the SNIPE mission has another astrophysical objective, detecting Gamma-Ray Bursts(GRB). By cross-correlating the light curves of the detected GRBs, the fleet shall be able to determine the time difference of the arriving signal between the satellites and thus determine the position of bright short bursts with an accuracy ~100'. To demonstrate the technology of the GRB observation, CSI gamma-ray detectors combined with GPS and IRIDIUM communication modules are placed on each SNIPE CubeSat. The time of each spacecraft is synchronized and when the GRB is detected, the light curve will be transferred to the Mission Operation Center (MOC) by IRIDIUM communication module. By measuring time difference of each GRB signals, the technology for localization of GRB will be proved. If the results show some possibilities, we can challenge the new astrophysical mission for investigating the origin of GRB.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.175-181
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• 2009

In this paper, we introduce the implementation of the security system using iris recognition. This system acquires images with infrared camera and extracts the 2D code from a infrared image which uses scale-space filtering and concavity. We examine the system by (i) extract 2D code and (ii) compare the code that stored on the server (iii) mearsure FAR and FRR using pattern matching. Experiment results show that the proposed method is very suitable.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1403-1411
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• 2012

In this paper, we have evaluated theoretically the PEA method which is the most popular methods for the non-destructive measurement of space charge distribution in polymer dielectric materials and is recently one of big issues in DC high voltage cables. On the basis of theoretical evaluation, we have developed the space charge measurement system in polymer dielectrics under DC appled voltage and improved the accuracy of space charge distribution by applying the deconvolution process for distorted signals.

• Proceedings of the Korea Society of Design Studies Conference
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• 2004.05a
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• pp.116-117
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• 2004

• Journal of information and communication convergence engineering
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• v.3 no.2
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• pp.76-79
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• 2005

In this paper, a low-complexity maximum-likelihood (ML) decoder based on QR decomposition, called real-valued LCMLDec decoder or RVLCMLDec for short, is proposed for the Vertical Bell Labs Layered Space-Time (V-BLAST) architecture, a promising candidate for providing high data rates in future fixed wireless communication systems [1]. Computer simulations, in comparison with other detection techniques, show that the proposed decoder is capable of providing the V­BLAST schemes with ML performance at low detection complexity

• Current Optics and Photonics
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• v.6 no.1
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• pp.23-31
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• 2022

Heterodyne efficiency is an indicator to evaluate the performance of space coherent laser communication systems. It is affected by signal light and local oscillator (LO) light amplitude, phase and polarization state. In this paper, based on the common heterodyne efficiency, a heterodyne efficiency model that can reflect polarization aberration of optical system is proposed. The heterodyne efficiency is analyzed when the signal light and the LO light are linearly polarized or circularly polarized. For a coherent communication optical system, when the incident signal light is right-circularly polarized light and the incident LO light is 45° linear polarized light. Based on the three-dimensional ray tracing theory and the heterodyne efficiency proposed in this paper, the change of polarization states and the distribution of heterodyne efficiency of the signal light and LO light influenced by the optical system's polarization aberration are analyzed. Analysis shows that the heterodyne efficiency model proposed in this paper can be used to evaluate coherent communication systems and reflect the influence of optical system polarization aberration.

• Journal of Space Technology and Applications
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• v.3 no.2
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• pp.144-153
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• 2023

The existing military satellite communication system was based on geostationary satellites equipped with special communication payloads against enemy's jamming and signal reception. With the advent of new weapon systems such as unmanned systems, the need for low-orbit satellite-based communication system is increasing. This paper introduces various waveform technologies suitable for cube satellite-based communication system and the operational concept of a future military nanosatellite communication system.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.65-71
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• 2009

In this paper a new space-time diversity relaying strategy using cooperative communication technique is proposed. More than one relaying terminals are included in one cooperative group to share their state information, such as frame error rate and channel state information. The best terminals are selected to send bit information using space-time diversity relay system. An implementation for the proposed scheme is also presented using the TDMA cooperative protocol. The resulting receive signal to transmit signal ratio and computer simulation demonstrate that the proposed strategy outperforms the conventional cooperative system.