• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.05a
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• pp.189-192
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• 2006

The development of digital technology makes our life more convenient in our lives and its calmness promotes the qualify of our life. Digital-home-automation system lets indoor-living more free, safe and clear so that it really has come true our life style that considers our mind and healthy to be important. Moreover, LED light source that combines the semiconductor with the digital technology has been tried as a current indoor illumination. Also the introduction of the light which has a high technology, like LED light, has been required in living space. It shows that it is very important to have an illuminated- plan which is accepted as well-developed technology. This study deals with the investigation into the user satisfaction of the existing residential area illumination and the investigation into the user satisfaction of the LED illumination being supplied for commercial area now. In the result, the fact is investigated that the user wants the introduction of the digital technology In the illumination because of a backward the residental area illumination in the circumstances being digital gradually. The inconvenience of the illumination used now should be minimized and the development of the LED illumination is a way satisfying the desire. The intended illumination project of the residential area should be accomplished according to the lifestyle of a changing residence.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.83-86
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• 2007

In the blind Maximum-likelihood (ML) detection for Orthogonal Space-Time Block Codes (OSTBC), the problem of ambiguity in determining the symbols has been a great concern. A solution to this problem is to apply semi-blind ML detection, i.e., the blind ML decoding with pilot symbols or training sequence. In order to increase the performance, the number of pilot symbols or length of training sequence should be increased. Unfortunately, this leads to a significant decrease in system spectral efficiency. This work presents an approach to resolve the aforementioned issue by introducing a new method for constructing transmitted information symbol. Thus, by transmitting information symbols drawn from different modulation constellation, the ambiguity can be easily eliminated in blind detection. Also, computer simulations are implemented to verify the performance of the proposed approach.

• Journal of Power Electronics
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• v.16 no.3
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• pp.936-945
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• 2016

Large magnitude common-mode voltage (CMV) and its variation dv/dt have an adverse effect on motor drives that leads to early winding failure and bearing deterioration. For matrix converters, the switch states that connect each output line to a different input phase result in the lowest CMV among all of the valid switch states. To reduce the output CMV for matrix converters, this paper presents a new space vector modulation (SVM) strategy by utilizing these switch states. By this mean, the peak value and the root mean square of the CMV are dramatically decreased. In comparison with the conventional SVM methods this strategy has a similar computation overhead. Experiment results are shown to validate the effectiveness of the proposed modulation method.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1146-1155
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• 2017

Normally, the artificial intelligence algorithms are widely applied to the optimal controller design. Then, it is expected that the best output performance is achieved. Unfortunately, when resulting controller parameters are implemented by using the practical devices, the output performance cannot be the best as expected. Therefore, the paper presents the optimal controller design using the combination between the state-space averaging model and the adaptive Tabu search algorithm with the new criteria as two penalty conditions to handle the mentioned problem. The buck-boost converter regulated by the cascade PI controllers is used as the example power system. The results show that the output performance is better than those from the conventional design method for both input and load variations. Moreover, it is confirmed that the reported controllers can be implemented using the realistic devices without the limitation and the stable operation is also guaranteed. The results are also validated by the simulation using the topology model of MATLAB and also experimentally verified by the testing rig.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.2
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• pp.144-150
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• 2022

The on-board processor of satellite synthetic aperture radar(SAR) generates transmission signal by digital signal processing, converts it into an analog signal. At this time, the transmission signal generated from the baseband requires the frequency modulation to convert it to the high-frequency band in order to improve the stability. General frequency modulation method using local oscillator(LO) causes IQ imbalance due to phase error/magnitude error and these error reduce performance of SAR. To generate transmission signal without phase/magnitude error, this paper suggests design method of the frequency modulation method using digital to analog converter(DAC) at on-board SAR. For design, this paper analyzes the characteristic of DAC mode and uses pre-compensation filter. To analyze the proposed method performance, performance index are compared with IQ imbalance signals. This method is suitable for on-board SAR using fast sampling DAC and has the advantage of being able to solve IQ imbalances.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.752-759
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• 2022

The instantiation of spaces as a discrete entity allows users to utilize BIM models in a wide range of analyses. However, in practice, their utility has been limited as spaces are erroneously entered due to human error and often omitted entirely. Recent studies attempted to automate space allocation using artificial intelligence approaches. However, there has been limited success as most studies focused solely on the use of geometric features to distinguish spaces. In this study, in addition to geometric features, semantic relations between spaces and elements were modeled and used to improve space classification in BIM models. Graph Convolutional Networks (GCN), a deep learning algorithm specifically tailored for learning in graphs, was deployed to classify spaces via a similarity graph that represents the relationships between spaces and their surrounding elements. Results confirmed that accuracy (ACC) was +0.08 higher than the baseline model in which only geometric information was used. Most notably, GCN was able to correctly distinguish spaces with no apparent difference in geometry by discriminating the specific elements that were provided by the similarity graph.

• Korean Journal of Construction Engineering and Management
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• v.24 no.4
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• pp.60-73
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• 2023

The need for adopting automation technologies to improve inefficiencies in interior finishing modeling work is increasing during the Building Information Modeling (BIM) design stage. As a result, the use of visual programming languages (VPL) for practical applications is growing. However, undefined or incorrect space designations in BIM models can hinder the development of automated finishing modeling processes, resulting in erroneous corrections and rework. To address this challenge, this study first developed a rule-based automated interior finishing detailing module for floors, walls, and ceilings. In addition, an automated space integrity checking module with 86.69% ACC using the Multi-Layer Perceptron (MLP) model was developed. These modules were integrated into a design automation module for interior finishing, which was then verified for practical utility. The results showed that the automation module reduced the time required for modeling and integrity checking by 97.6% compared to manual work, confirming its utility in assisting BIM model development for interior finishing works.

• The Korean Journal of Air & Space Law and Policy
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• v.20 no.2
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• pp.159-234
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• 2005

As so clearly have been demonstrated in the Gulf War and Iraq Freedom Fight, along with the civilian space exploration and development, the 'militarization' of aerospace technology and the 'battlefield-worthiness' of space are becoming more and more at issue. Korean peninsula, the last major theatre where the 4 world powers' national interests stand face to face, no doubt is in dire need for understanding and organizing necessary legislations for establishing national security from any space threats, such as satellite imaging, as well as countering against such threats. Compare to United States, Japan and China that have already declared the national security as the purpose of the space development, and equipped themselves with necessary legislations, Korea's legislations fall short of fully appreciating and effectively responding to the significance of military use of outer space and its control. This article will review legislations of leading countries' of space law and space technologies from two different perspectives. After briefly summarizing the problems of Korea's current legislations, particularly with the National Space Development Act (proposal), drafted by Ministry of Science and Technology, in mind, this article reviews and offers certain legislative directions to which Korea should pursuel for national security of outer space.

• Journal of Astronomy and Space Sciences
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• v.22 no.4
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• pp.473-482
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• 2005

Many technical challenges are being tried for a large space infrared telescope, which is one of the major objectives of the Strategic Technology Road Map (STRM) of KASI (Korea Astronomy and Space Science Institute), As one of these challenges, KASI and KBSI (Korea Basic Science Institute) have started a cooperation project for developing a space infrared cryogenic system with KIMM (Korea Institute of Machinery as Materials) and i3system co. In this paper, we generate optical requirements for the Protomodel of Space Infrared Cryogenic System (PSICS), and design a single lens optical system with a bandpass of $3.8\~4.8{\mu}m$, a field of view of $15^{\circ}\times12^{\circ}$, and an angular resolution of $0.047^{\circ}$, to develop a further complex optical system.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.58.2-58.2
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• 2016

The NISS (Near-infrared Imaging Spectrometer for Star formation history) onboard NEXTSat-1 is the near-infrared instrument optimized to the first small satellite of NEXTSat series. The capability of both imaging and low spectral resolution spectroscopy with the Field of View of $2{\times}2deg.$ in the near-infrared range from 0.9 to $3.8{\mu}m$ is a unique function of the NISS. The major scientific mission is to study the cosmic star formation history in local and distant universe. The Flight Model of the NISS is being developed and tested. After an integration into NEXTSat-1, it will be tested under the space environment. The NISS will be launched in 2017 and it will be operated during 2 years. As an extension of the NISS, SPEHREx (Spectro-Photometer for the History of the Universe Epoch of Reionization, and Ices Explorer) is the NASA SMEX (SMall EXploration) mission proposed together with KASI (PI Institute: Caltech). It will perform an all-sky near-infrared spectral survey to probe the origin of our Universe; explore the origin and evolution of galaxies, and explore whether planets around other stars could harbor life. The SPHEREx is designed to have wider FoV of $3.5{\times}7deg.$ as well as wider spectral range from 0.7 to $4.8{\mu}m$. After passing the first selection process, SPHEREx is under the Phase-A study. The final selection will be made in the end of 2016. Here, we report the current status of the NISS and SPHEREx missions.