• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.3
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• pp.44-51
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• 2001

In general, the realization of spaceborne system is constrained by its space environment. In this paper, we suggest chirp stitching technique which generates and processes wideband radar signal with minimum hardware, design and implement transmit/receive equipments and operating programs to satisfy the requirement of this spaceborne high resolution SAR(Synthetic Aperture Radar). We apply the top down design approach to this system, and divide hardware into equipment, module and circuit levels, and software into SR(Software Requirement), AD(Architecture Design), DD(Detailed Design) and coding levels, and then extract each requirement to satisfy the wideband requirement of this spaceborne high resolution SAR. We, at first, test the hardware functions, confirm the wideband handling capability of this system with 85MHz wideband signals generated from two 42.5MHz narrow band signals, and show that this system can be used in spaceborne high resolution SARs.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.30.2-30.2
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• 2011

In this report, we present in-orbit radiometric performance prediction for the Amon-Ra (Albedo Monitor and Radiometer) energy channel instrument. The Integrated Ray Tracing (IRT) computational technique uses the ray sets arriving at the Amon-Ra instrument aperture orbiting around the L1 halo orbit. Using this, the variation of flux arriving at the energy channel detector was obtained when the Amon-Ra instrument including the energy channel design observes the Sun and Earth alternately. The flux detectability was verified at the energy channel detector (LME-500-A, InfraTecTM). The detector time response and RMS signal voltage were then derived from the simulated flux variation results. The computation results demonstrate that the designed energy channel optical system satisfies the in-orbit detectability requirement. The technical details of energy channel instrument design, IRT model construction, radiative transfer simulation and output signal computation results are presented together with future development plan.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.25.4-26
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• 2010

We present a three-mirror anastigmat(TMA) optical system for New Generation GOCI. In order to reduce the ghost optimized filter and baffle. By using carefully chosen antireflective coating and tilted filter angle, we fulfilled the design SNR requirement of 1500. We then designed a new entrance baffle and an internal baffle capable of producing the ghost ratio better than 0.01% of the nominal signal. The entrance baffle limits FOV to $0.75^{\circ}$ (E/W) $\times$ $0.60^{\circ}$ (S/N), and prevents the system from strong sun illumination, and the internal baffle prevents stray and scattered ray from entering into the telescope cavity. From these filter and baffle design, we confirmed that the instrument signal to noise ratio can be met with the current conceptual opto-mechanical design.

• Korean Institute of Interior Design Journal
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• v.15 no.1 s.54
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• pp.166-174
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• 2006

The purpose of this study was to analyze the residents' cognition and behaviors about residents' community space in apartment housing. Since the last year when well-being trend was highly interesting, consumers have showed their concern about not only just interior of houses but also exterior environment of their houses. This movement has evoked consumers' interests in level and sort of residents' community space. Moreover, as the concern about the quality of human life has gone up, how much the quality of human life could get higher has been brought into relief as an absolutely important issue. According to this trend, this study researched residents' satisfaction, the reason of dissatisfaction, requirement, and preference about residents' community space to analyze residents' cognition and behaviors about residents' community space in apartment. Therefore, this study did following; First, it selected research samples which have the value to be researched and outstanding productivity. Second, sample survey was performed to residents with questionnaire and results of the survey were analyzed. The contents of questionnaire included the actual condition, residents' cognition, and behaviors of residents' community space.

• Journal of KIBIM
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• v.14 no.3
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• pp.1-12
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• 2024

Many efforts are being made to enhance user productivity and promote collaboration while ensuring the economic efficiency of office buildings. Analyzing space utilization, indicating how users utilize spaces, has been a crucial factor in these efforts. Appropriate space utilization enhances building maintenance and space layout design, reducing unnecessary energy waste and under-occupied spaces. Recognizing the importance of space utilization, there have been several studies to predict space utilization using information about users, activities, and spaces. These studies suggested an ontology of the information and implemented automated activity-space mapping as part of space utilization prediction. Despite the existing studies, there remains a gap in integrating space utilization prediction with automated space layout design. As a foundational study to bridge this gap, our study proposes a novel methodology that automatically generates office rooms based on space utilization optimization. This methodology consists of three modules: Activity-space mapping, Space utilization calculation, and Room generation. The first two modules use data on space types and user activity types as input to calculate and optimize space utilization through requirement-based activity-space mapping. After optimizing the space utilization value within an appropriate range, the number and area of each space type are determined. The Room generation module then automatically generates rooms with optimized areas and numbers. The practical application of the developed methodology is demonstrated, highlighting its effectiveness in fabricated case scenario. By automatically generating rooms with optimal space utilization, our methodology shows potential for expanding to automated generation of optimized space layout design based on space utilization.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.535-550
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• 2016

Securing the safety and the reliability of liquid-propellant rocket engines (LREs) for space vehicles is indispensable as engines consist of many complex components and operate under extremely high energy-dense conditions. Thus, health monitoring has become a mandatory requirement, especially for the reusable LREs that are currently being developed. In this context, a dynamic simulation program based on MATLAB/Simulink was developed in the current research on the Space Shuttle Main Engine (SSME), a partly reusable engine. Then, a series of fault simulations using this program was conducted: at a steady state operating condition (104% Rated Propulsion Level), various simulated fault conditions were artificially injected into the simulation models for the five major valves, the pumps, and the turbines of the SSME. The consequent effects due to each fault were analyzed based on the time responses of the major parameters of the engine. It is believed that this research topic is an essential pre-step for the development of fault detection and diagnosis algorithms for reusable engines in the future.

• Journal of Astronomy and Space Sciences
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• v.22 no.1
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• pp.35-46
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• 2005

This paper addresses the design and analysis results of a 2-axes magnetometer for attitude determination of small satellite. A low-cost and efficient 2-axes fluxgate magnetometer was selected as the most suitable attitude sensor for LEO microsatellites which require a low-to-medium level pointing accuracy. An optimization trade-off study has been performed for the development of 2-axes fluxgate magnetometer. All the relevant parameters such as permeability, demagnetization factor, coil diameter, core thickness, and number of coil turns were considered for the sizing of a small satellite magnetometer. The magnetometer which is designed, manufactured, and tested in-house as described in this paper satisfies linearity requirement for determining attitude position of small satellites. On the basis of magnetometer which is designed in Space System Research Lab. (SSRL), commercial magnetometer will be developed.

• Korean Institute of Interior Design Journal
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• v.15 no.2 s.55
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• pp.127-137
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• 2006

In the viewing of public performance arts, it needs to make space construction appropriate for performance purposes, because the section type has an effect on audience's inspection. Therefore, this study researches the intentional characteristics and comprehends the relationship between correlation factors to influence on section type of audience space in performance facilities. In addition to, this study comes under fundamental research to propose the course of standard plan, accord with diverse requirement, in the special performance facilities which will be built up. The results as following; 1) The factors that influence the section type of the audience's space in performing facilities are divided as two elements. The first element is construction of space, viewing environment, and the second element is visual characteristic, and acoustic characteristic. 2) The section type are classified as six types, A-type(Flated type), B-type(Sloped type), C-type(Gabled type), D-type(Arched type), E-type(Reverse arched type), and F-type(Reverse sloped type). 3) Characteristics are deduced by the section type, construction of space and viewing environment are restricted by the characteristics of the section type.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1240-1245
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• 2000

A Spacecraft container must afford the satellite a relatively benign thermal, vibration, and particle environment that is oblivious to the extreme temperatures, sand, dust, vibrations and shocks that can accompany the transportation. This paper discusses the extensive yet simple vibration test and validation of one such spacecraft container used for KOMPSA T-1 spacecraft, which was transported from KARl Taejon, Korea to Vandenberg Air Force Base(VAFB) on September 30 and launched successfully December 21, 1999. The test results are presented and compared with the design requirement. The dynamic characteristics of shipping container, such as natural frequencies, satisfied the design requirement and showed that shipping container was well. designed and manufactured. This kind of know-how will help to develop the next generation of Korean space program, such as KOMPSAT-2 and Korean tele-communication satellite.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.479-483
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• 2003

In general, urban railroad in Korea is constructed as a tunnel type under ground due to the various restricted conditions. Passengers in train running through underground tunnel compare to open space are exposed to severe noise environment. In this study, various performance characteristics of many candidate materials are surveyed and analyzed. And some important characteristics are tested. From this study, various performance requirement for noise reduction in railway tunnel were suggested.