• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.3
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• pp.427-432
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• 2017

This study describes the design and implementation of SHF band Downconverter Digital Satellite Communication. The SHF band Downconverter unit consists of PLDRO and Frequency converter. In Frequency converter, microstrip BPF and LPF designed through the pre EM simulation are implemented to minimize the unwanted spurious in Frequency converter. Through the pre-simulation analysis of space environment, the possibility of and minimized about the malfunction of equipment and we designed a reliable SHF band Downconverter through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of SHF band Downconverter after production.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.12
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• pp.1159-1164
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• 2016

This study describes the design and implementation of SHF band Low Noise Amplifier of Digital Satellite Communication. We have applied to HEMT part to minimize Noise Figure of system. and minimized the potential for the occurrence of such erroneous operation of equipment through the simulations of the space environment. We designed a reliable Low Noise Amplifier through simulation for a TID according to the vibration generated during the launch and space radiation environment, and compared pre-simulation of main performance results to test results about main performances of Low Noise Amplifier after production.

• Journal of The Korean Digital Architecture Interior Association
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• v.9 no.3
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• pp.85-93
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• 2009

In this study, the ex-formal expressions observed in space form of Korean modern architecture are distributed for characteristic analysis based on the period and type. The result of the study is certified by the work analysis and the result is as follows. Initially, due to the limited materials and influence of western brutalism, the works developed during 1960~70 tend to be plastic and contain expressionism. Around 1980's, the works tend to show forms of amusement and popularity. In 1990's the works show significance in deconstructive expression. From after 2000, ecological concept of architecture was introduced and organic expression started increasing Secondly, the ex-formal expressions are found to be in four different types. The organic expression is shown regardless of the period. In modern days, not only the physical properties of materials, but also the ecological concept is combined with the organic expression and is in increase. The plural expression started appearing after the 1980's and the sculptural diversity is enhancing with the addition of decorative factors or modification of geometrical form. The ex-construction and deconstructive expression show significance in some characteristics such as folding, inclination, and geometrical explosion. The free form and nonlinear expression tend to increase dramatically based on the development of structure technology as well as execution and introduce of the digital design technique.

• 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.

• Journal of Astronomy and Space Sciences
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• v.34 no.2
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• pp.119-125
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• 2017

We retrieved rotational temperatures from emission lines of the OH airglow (8-3) band in the sky spectra of the Sloan digital sky survey (SDSS) for the period 2000-2014, as part of the astronomical observation project conducted at the Apache Point observatory ($32^{\circ}N$, $105^{\circ}W$). The SDSS temperatures show a typical seasonal variation of mesospheric temperature: low in summer and high in winter. We find that the temperatures respond to solar activity by as much as $1.2K{\pm}0.8K$ per 100 solar flux units, which is consistent with other studies in mid-latitude regions. After the seasonal variation and solar response were subtracted, the SDSS temperature is fairly constant over the 15 year period, unlike cooling trends suggested by some studies. This temperature analysis using SDSS spectra is a unique contribution to the global monitoring of climate change because the SDSS project was established for astronomical purposes and is independent from climate studies. The SDSS temperatures are also compared with mesospheric temperatures measured by the microwave limb sounder (MLS) instrument on board the Aura satellite and the differences are discussed.

• Journal of The Korean Digital Architecture Interior Association
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• v.7 no.2
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• pp.51-58
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• 2007

The saying likely as "In the rapidly-changing outside management environment, the light-weighted body only able to survive" means the 'lightness' in working space, reducing expenditure for immovable property and unnecessary facility, and also means the flexibility of facility which is ready to cope promptly with the approaching situation. For such reason, as many enterprises do not support an individual workstation for each person but by introduction of sharing system, also reducing the area for working space, they have made the immovable property expense per person curtailed. Though the reduction of the immovable property expense that subsequently gained by merely decreasing of working space brings a remarkable effect of retrenchment, there is also a worrying opinion that because of the narrowed working space than before, or by disappearing of private space, a possible non-productive effect which let working enthusiasm falls down might be brought. By practicing such investigating method, at the first stage survey, the Satisfaction of non-territorial and territorial office user and the order of required improvement are figured out, also arranged the appraisal items as 6 factors in total, and all of the factors were being influenced to the entire satisfaction in statistically meaningful level.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.2
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• pp.127-138
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• 2013

The impact of Empty Space layer in the channel region of a Double Gate (i.e. ESDG) MOSFET has been studied, by monitoring the DC, RF as well as the digital performance of the device using ATLAS 3D device simulator. The influence of temperature variation on different devices, i.e. Double Gate incorporating Empty Space (ESDG), Empty Space in Silicon (ESS), Double Gate (DG) and Bulk MOSFET has also been studied. The electrical performance of scaled ESDG MOSFET shows high immunity against Short Channel Effects (SCEs) and temperature variations. The present work also includes the linearity performance study in terms of $VIP_2$ and $VIP_3$. The proper bias point to get the higher linearity along with the higher transconductance and device gain has also been discussed.

• Journal of Information Processing Systems
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• v.13 no.4
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• pp.876-892
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• 2017

A virtual reality is a virtual space constructed by a computer that provides users the opportunity to indirectly experience a situation they have not experienced in real life through the realization of information for virtual environments. Various studies have been conducted to realize virtual reality, in which the user interface is a major factor in maximizing the sense of immersion and usability. However, most existing methods have disadvantages, such as costliness or being limited to the physical activity of the user due to the use of special devices attached to the user's body. This paper proposes a new type of interface that enables the user to apply their intentions and actions to the virtual space directly without special devices, and test content is introduced using the new system. Users can interact with the virtual space by throwing an object in the space; to do this, moving object detectors are produced using infrared sensors. In addition, the users can control the virtual space with their own postures. The method can heighten interest and concentration, increasing the sense of reality and immersion and maximizing user's physical experiences.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.5
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• pp.297-311
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• 2021

Around the world, there is an increasing interest in Digital Twin cities. Although geospatial data is critical for building a digital twin city, currently-established spatial data cannot be used directly for its implementation. Integration of geospatial data is vital in order to construct and simulate the virtual space. Existing studies for data integration have focused on data transformation. The conversion method is fundamental and convenient, but the information loss during this process remains a limitation. With this, standardization of the data model is an approach to solve the integration problem while hurdling conversion limitations. However, the standardization within indoor space data models is still insufficient compared to 3D building and city models. Therefore, in this study, we present a comparative analysis of data models commonly used in indoor space modeling as a basis for establishing a generic indoor space feature model. By comparing five models of IFC (Industry Foundation Classes), CityGML (City Geographic Markup Language), AIIM (ArcGIS Indoors Information Model), IMDF (Indoor Mapping Data Format), and OmniClass, we identify essential elements for modeling indoor space and the feature classes commonly included in the models. The proposed generic model can serve as a basis for developing further indoor feature models through specifying minimum required structure and feature classes.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.233-242
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• 2019

Numerous space perception studies have shown that Euclidean 3-D structure cannot be recovered from binocular stereopsis, motion, combination of stereopsis and motion, or even with combined multiple sources of optical information. Humans, however, have no difficulties to perform the task-specific action despite of poor shape perception. We have applied humans skill and capabilities to artificial intelligence and computer vision but those machines are still far behind from humans abilities. Thus, we need to understand how we perceive depth in space and what information we use to perceive 3-D structure accurately to perform. The purpose of this paper was to review space perception literatures to apply humans abilities to artificial intelligence robots more advanced in future.