• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.7
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• pp.586-593
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• 2014

The CNUSAIL-1 project aims to develop and operate a 3U-sized cube satellite with solar sail mechanism. The primary mission is to successfully deploy the solar sail in a low earth orbit, and the secondary mission is to collect the scientific data for the effect of the solar sail deployment and operation on orbit maneuver and attitude change of the cube satellite. For this, the bus system will collect and transmit the dynamic data of the satellite and the visual images of the solar sail operation. This paper describes solar sail mission and conceptual design of CNUSAIL-1. The actuation/operation of the solar sail and the bus system are preliminarily designed in terms of attitude control system, communication system, electrical power system, command and data handling system, structure and thermal control system is designed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.1
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• pp.13-20
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• 2022

Aircraft weight is an important factor affecting performance and fuel efficiency. In the conceptual design stage of the aircraft, the process of balancing cost and weight is performed using empirical formulas such as fuel consumption cost per weight in estimating element weight. In addition, when an airline operates an aircraft, it promotes fuel efficiency improvement, fuel saving and carbon reduction through weight management activities. The relationship between changes in aircraft weight and changes in fuel consumption is called the cost of weight, and the cost of weight is used to evaluate the effect of adding or reducing weight to an aircraft on fuel consumption. In this study, the problems of the existing cost of weight calculation method are identified, and a new cost of weight calculation method is introduced to solve the problem. Using Breguet's Range Formula and actual flight data of the A350-900 aircraft, two weight costs are calculated based on take-off weight and landing weight. In conclusion, it was suggested that it is reasonable to use the cost of weight based on the take-off weight and the landing weight for other purposes. In particular, the cost of weight based on the landing weight can be used as an empirical formula for estimating element weight and optimizing cost and weight in the conceptual design stage of similar aircraft.

• Journal of Korean Library and Information Science Society
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• v.50 no.4
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• pp.33-55
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• 2019

A marketing platform based on the legal deposit system was designed. It is an e-book distribution platform that systematically binds library networks nationwide by linking with the National Library's deposit system to complete the existing paper that the library should become a publishing platform. The purpose is to bundle e-books into a distribution space and naturally assemble readers to serve as virtual platforms for domestic publishers, authors, bookstores, and platforms running various publishing / subscribing services. The premise is not a sale of e-books, but a rental concept, but the platform is valid regardless. In addition, the platform takes the form of social cooperatives to represent the interests of all members involved in publishing services. The lead-based distribution platform is the most ideal business model to compromise with reality. Conceptually, the service of the publishing content-related industry is a model in which all content is supplied from the lead-bone system, which is a collaborative space, and technically, the central e-book database controls the flow of all content, but the publishing content-related industry takes the form of controlling its flow through virtual.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.11
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• pp.883-890
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• 2013

Aircraft combat survivability analysis is essential process for the development of combat aircraft. M&S methodology is the typical procedure for the aircraft combat survivability analysis, and the last step is the expensive Live Fire Test if it is necessary. This study introduced cost and time effective survivability analysis methodology based on the random variable weighted score algorithm in conceptual design phase. For this study, essential element and event analysis (E3A) is used to define the random variables and Monte-Carlo simulation is implemented to estimate weighted score and the final value of survivability.

• Korean Institute of Interior Design Journal
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• v.15 no.5 s.58
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• pp.85-94
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• 2006

Due to multidisciplinary characteristic of the Interior Design field, it has developed into complex interdisciplinary field. Therefore Interior Design field has grown and established its major trends dependent upon other related field of study. With this perspective in mind, esthetics on Interior Design has to be treated in similar manner. In modem architects or artists have defined the terminology 'object' theoretical principle where by unable to distinguish between 'object's type' and 'objects', Presently, the term 'object' became a trend word. In order to confront misconception of the idea of 'Objectification', some people definition as reflection of this complex society. In this paper, it will establish a solid groundwork for a discussion on Objectification. The initial approach will deal with Le Corbusier and esthetics, which is the center of argument. By reviewing theoretical background of the related modern art, the paper discusses about the relationship between Le Corbusier and esthetics. Subsequently, the discussion about the criterions necessary to define object is provided. This paper only suggests a methodology of analyzing a trend in Interior Design. The condition to define Objectification in Interior Design, which is a result of the reviewing process on esthetics, can be concluded as 'modeling form(transformation of morphological meaning with change wrought by causing a visual reaction)', 'mixtures and modification of materials(transformation and spontaneity through mixing materials)' and 'elements greatly influence space' of the Interior Design.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.7
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• pp.583-591
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• 2018

In this paper, we propose a new deployment test equipment that is characterized for the deployment test of single large solar panel with tape spring hinge. To perform the deployment test on ground, a device that takes gravity compensation into account should be used to create a zero gravity environment similar to that in orbit. We analyzed the advantages and disadvantages of the most commonly used deployment test equipment in the past through simple conceptual design, analysis, and tests to judge whether it is applicable to the deployment of the solar panel to be tested. A dummy frame was proposed to reduce the air drag effect during on-ground test and a self-aligning ball bearing and adjusting screws were applied to the deployment test equipment to solve the alignment problem with the gravity axis. And a horizontal bearing for radial movement applied to compensate for the change of the axis of the tape spring hinge. From these, we solved the problems of the conventional deployment test equipment by developing and verifying the new deployment test equipment characterized for the solar panel to be deployed in this paper.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.148-155
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• 2002

A study on the installation angle of solar panels is conducted as a conceptual study on solar-RFC(regenerative fuel cell) system for stratospheric airships. The airship heads for the west in winter days and the east in summer days according to wind directions. Considering this, it is found that when the solar panel is installed with the center angle of 30 degree the energy output of solar panels is maximized on winter solstice and satisfies the required energy of summer days as well. Although with the optimized solar panel installation angle, efficiency of the regenerative power system needs be improved to 47% to provide required energy of a 170m-long airship. And the required amount of efficiency improvement decreases as the airship size increases.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.41-47
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• 2005

Even more than 240 commercial geostationary communication satellites currently on orbit at the higher location than the GPS orbit altitude perform their own missions only by the support of the ground segment because of weak visibility from GPS. In addition, the orbit determination accuracy is very low without using two or more dedicated ground tracking antennas in intercontinental ground segment, since the satellite hardly moves with respect to the ground station. In this paper, we propose the GSPS(Geostationary Satellite Positioning System) in circular orbits of two sidereal days period higher than the geosynchronous orbit for orbit determination and autonomous satellite operation. The GSPS is conceived as a ranging system in that unknown positions of a geostationary satellite can be acquired from the known positions of the GSPS satellites. Each GSPS satellite transmits navigation data, clock data, correction data, and geostationary satellite command to control a geostationary satellite.

• Journal of Educational Research in Mathematics
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• v.15 no.1
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• pp.21-38
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• 2005

The purpose of this research is to develop a probability program based on the actual condition of understanding of probability by the elementary school students from 3rd to 6th grade and search for ways to apply it to the 3rd grade of elementary school students. Based on the results from the research, the author reached a conclusion as following. After applying the learning program to five students of 3rd grade, all of the five students made progress understanding the concept of experimental and theoretical probability. However, for understanding the concept of example space, only two leading students were improved, which shows that students are having much difficulty in understanding the concept. As for under-standing the concept of experimental probability, many students gained the conceptual difference between the experimental and theoretical probability after using the program and enhanced their understanding of experimental probability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.1
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• pp.69-75
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• 2009

This paper studies the aerodynamic performance that the vent mixer-new conceptual supersonic mixer-showed with its geometric characteristics. The hole is 2 mm with 2 mm's distance from the wall in case 1 and with no distance in case 2. In case 3 die hole is 1 mm. Case 1 and case 2 showed the same total pressure recovery ratio, of which the case 3 was lower than that. While cases 1-3 had the same reattachment length, the shear layer was thicker in cases 1 and 2 than in case 3. Within the recirculation zone, cases 1 and 2 had lower pressure loss and higher velocity gradient difference than case 3-they enhance mixing between air and fuel. Separation bubble which is developed by the inflow into the recirculation zone has a significant effect on the total pressure recovery ratio in the combustor. Also separation bubble influences pressure distributions and recirculation flows in the recirculation zone. Therefore, inflow rate of air into the recirculation zone mainly affects the performance of vent mixer.