• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.23-31
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• 2019

The design requirements of modern satellites vary depending on the purpose of operation. Like conventional medium and large-scale satellites, small satellites which operate on low orbit may also serve military purposes. As a result, there is increased demand for high-resolution photos and videos and multi-target observation becomes important. The most important design parameter for multi-target observation is the satellites' maneuverability. For increased maneuverability, the miniaturization is required to increase the stiffness of the satellite as this decreases the mass moment of inertia of the satellite. In the case of a solar panel having relatively low stiffness compared to the satellites' body, vibrations are generated when the attitude maneuver is performed, which greatly influences the image acquisition. For verification of such vibrational characteristics, the satellites is modeled as a reduced model, and experimental zig for simulating attitude maneuver is introduced. A rigidity simulator for simulating the stiffness of the satellite is also proposed. Additionally, the objective of the experimental method is to simulate the maneuvering angle of the satellite based on the winding length of the wire using a step motor, and to experimentally verify the vibration characteristics of the satellite body and the solar panel generated during the maneuvering test.

• Journal of The Korean Association For Science Education
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• v.38 no.6
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• pp.781-792
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• 2018

In modern society, as technology develops and industry diversifies, students can choose from a variety of career paths. Since science, technology, engineering, and mathematics require a longer education and experience than other fields, it is important to design science education policies based on the competencies required for science, technology, engineering, and mathematics (STEM) occupations. This study explores the definition of science and technology manpower and STEM occupations and identifies core competencies of STEM occupations using standard job information operated and maintained by the US Department of Labor ($O^*NET$). We specially analyzed ratings of the importance of skills (35 ratings), knowledge (33 ratings), and work activities (41 ratings) conducting descriptive analysis and principal component analysis (PCA). As a result, core competencies of STEM occupations consist of STEM problem-solving competency, Management competency, Technical competency, Social service competency, Teaching competency, Design competency, Bio-chemistry competency, and Public service competency, which accounts for 70% of the total variance. This study can be a reference for setting the curriculum and educational goals in secondary and college education by showing the diversity of science and technology occupations and the competencies required for STEM occupations.

• Animal Bioscience
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• v.35 no.12
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• pp.1911-1920
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• 2022

Objective: This study was performed to determine the apparent metabolizable energy (AME_n) content of tannin-free red/bronze, white/tan and U.S. No. 2 varieties of grain sorghum for feeding Japanese quail and validate their nutrient profile by evaluating effects on performance and carcass traits with full-substitution of corn. Methods: Experiment 1 determined the AME_n content of red/bronze, white/tan, and U.S. No. 2 grain sorghum varieties fed to mixed-sex Japanese quail (Coturnix japonica) (n = 314) at 3 and 6-weeks of age. Analyses were based on a 2×4 factorial treatment design with age and grain types defining the treatments, and a randomized complete block experiment design with cage and trials defining the block. AME_n values were validated by evaluating the performance and carcass traits of Japanese quail (n = 644) from 1 to 40 days of age in Experiment 2 with birds were fed 1 of 4 complete diets. Statistical analyses were conducted on performance data and select individual carcass trait measurements. Results: Determined AME_n values at 3-weeks of age were 3,524±122.03 (red/bronze), 3,252±122.03 (white/tan), and 3,039±123.44 (U.S. No. 2) kcal/kg. At 6-weeks of age, determined AME_n were 3,373±297.35 (red/bronze), 3,279±297.35 (white/tan), and 2,966±298.64 (U.S. No. 2) kcal/kg. Carcass traits showed live body weight (p = 0.0409) and hot carcass weight (p = 0.0234) were greatest in U.S. No. 2; however, carcass yield (p<0.0001) was lowest. No significant differences were observed among treatments for feed intake, feed conversion ratio, breast weight and breast yield (p>0.05). Conclusion: These studies demonstrated that tannin-free grain sorghum varieties may be a potential alternative to corn in quail diets while maintaining growth performance and carcass parameters.

• Advances in aircraft and spacecraft science
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• v.9 no.5
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• pp.415-431
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• 2022

Secondary flows have a huge impact on losses generation in modern low pressure gas turbines (LPTs). At design point, the interaction of the blade profile with the end-wall boundary layer is responsible for up to 40% of total losses. Therefore, predicting accurately the end-wall flow field in a LPT is extremely important in the industrial design phase. Since the inlet boundary layer profile is one of the factors which most affects the evolution of secondary flows, the first main objective of the present work is to investigate the impact of two different inlet conditions on the end-wall flow field of the T106A, a well known LPT cascade. The first condition, labeled in the paper as C1, is represented by uniform conditions at the inlet plane and the second, C2, by a flow characterized by a defined inlet boundary layer profile. The code used for the simulations is based on the Discontinuous Galerkin (DG) formulation and solves the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the Spalart Allmaras turbulence model. Secondly, this work aims at estimating the influence of viscosity and turbulence on the T106A end-wall flow field. In order to do so, RANS results are compared with those obtained from an inviscid simulation with a prescribed inlet total pressure profile, which mimics a boundary layer. A comparison between C1 and C2 results highlights an influence of secondary flows on the flow field up to a significant distance from the end-wall. In particular, the C2 end-wall flow field appears to be characterized by greater over turning and under turning angles and higher total pressure losses. Furthermore, the C2 simulated flow field shows good agreement with experimental and numerical data available in literature. The C2 and inviscid Euler computed flow fields, although globally comparable, present evident differences. The cascade passage simulated with inviscid flow is mainly dominated by a single large and homogeneous vortex structure, less stretched in the spanwise direction and closer to the end-wall than vortical structures computed by compressible flow simulation. It is reasonable, then, asserting that for the chosen test case a great part of the secondary flows details is strongly dependent on viscous phenomena and turbulence.

• Journal of the Korea Society for Simulation
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• v.19 no.1
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• pp.63-71
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• 2010

In modern war, Intercept Performance of SAM(Surface to Air Missile) is gaining importance as range and precision of Missile and Guided Weapon on information warfare have been improved. An aerial defence system using Surface-to-air Radar and Guided Missile is needed to be built for prediction and defense from threatening aerial attack. When developing SAM, M&S is used to free from a time limit and a space restriction. M&S is widely applied to education, training, and design of newest Weapon System. This study was conducted to develop simulator for evaluation of Intercept Performance of SAM. In this study, architecture of Intercept Performance of SAM analysis simulator for estimation of Intercept Performance of various SAM was suggested and developed. The developed Intercept Performance of SAM analysis simulator was developed by C++ and Direct3D, and through 3D visualization using the Direct3D, it shows procedures of the simulation on a user animation window. Information about design and operation of Fighting model is entered through input window of the simulator, and simulation engine consisted of Object Manager, Operation Manager, and Integrated Manager conducts modeling and simulation automatically using the information, so the simulator gives user feedback in a short time.

• International Journal of Advanced Culture Technology
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• v.10 no.1
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• pp.248-252
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• 2022

The environment refers to what is surrounded by something during human life. This environment is related to the way humans live, and presents various problems on how to perceive the surrounding environment and how the behaviors that constitute the environment support the elements necessary for human life. Humans have an interest in the supportability of the environment as the interrelationship increases as humans perceive and understand the environment and accept the factors supported by the environment. In space, human movement starts from one space to the next and exchanges stimuli and reactions with the environment until reaching a target point. These human movements start with subjective judgment and during gait movement, the spatial environment surrounding humans becomes a collection of information necessary for humans and gives stimulation. will do. In this process, in particular, humans move along the movement path through movement in space and go through displacement perception and psychological changes, and recognize a series of spatial continuity. An image of thinking is formed[1]. In this process, spatial experience is perceived through the process of filtering by the senses in the real space, and the result of cognition is added through the process of subjective change accompanied by memory and knowledge, resulting in human movement. As such, the spatial search behavior begins with a series of perceptual and cognitive behaviors that arise in the process of human beings trying to read meaning from objects in the environment. Here, cognition includes the psychological process of sorting out and judging what the information is in the process of reading the meaning of the external environment, conditions, and material composition, and perception is the process of accepting information as the first step. It can be said to be the cognitive ability to read the meaning of the environment given to humans. Therefore, if we can grasp the perception of space while moving and human behavior as a response to perception, it will be possible to predict how to grasp it from a human point of view in a space that does not exist. Modern people have the theme of reminiscing dog-friendly hotels for the healing of petloss syndrome, and this thesis attempts to approach the life of companions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.139-145
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• 2024

This paper presents the design of a voltage controlled oscillator (VCO) which is one of the key building blocks in modern wireless communication systems with small VCO gain (K_vco) variation. To compensate conventional large K_vco variation, a series varactor bank has been added to the conventional LC-tank with parallel capacitor bank array. And also, in order to achieve excellent phase noise performance while maintaining wide tuning range, a mixed coarse/fine tuning scheme(series varactor array and parallel capacitor array) is chosen. The switched varactor array bank is controlled by the same digital code for switched capacitor array without additional digital circuits. For use at a low voltage of 1.2V, the proposed current reference circuit in this paper used a current reference circuit for safety with the common gate removed more safely. Implemented in a TSMC 0.13㎛ CMOS RF technology, the proposed VCO can be tuned from 4.4GH to 5.3GHz with the K_vco (VCO gain ) variation of less than 9.6%. While consuming 3.1mA from a 1.2V supply, the VCO has -120dBc/Hz phase noise at 1MHz offset from the carrier of the 5.3 GHz.

• Journal of Science of Art and Design
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• v.11
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• pp.5-35
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• 2007

When it comes to art, the two conflicting themes of 'scientific progress' and the 'nature' have often motivated the advent of the new mode of arts. By the late 20th century, uniform and simplified mode of arts, inspired by scientific and technological progress of that time, was gradually disillusioned by the contemporaries due to the adverse effect of science on human life. In this context, naturalism pursuing for harmony of human and the nature came up as an alternative to those living in the 21st century. The pendulum has swung from minimalism to naturalism. Though the quantitative improvement of human life cannot be denied, the uprise of such problems as environmental pollution and exhaustion of natural resources degraded the quality of human life, which, eventually, shifted the attention to the theme - 'revival of naturality.' Therefore, this thesis intends to represent the modem interpretation of the 'revival of naturality' by applying the major expressions of Art Nouveau that also emphasized naturalism. Art Nouveau found its motifs from organic figures of natural beings and put them to designs of decorative arts. This carries a historical significance in that Art Nouveau boldly revolutionized historicism, which only repeated adoption and modification of the existing modes of arts, and opened it to the modem design with new attempts to practical applications of the arts. Art Nouveau, which means 'new art', prospered from the late 19th century to the early 20th century, and even after one century, it is highly appreciated, reviving as novel and vivid forms in this contemporary art. Art Nouveau based on naturalism has revisited our contemporary period when naturalism and feminized romanticism came into fashion and its common motifs revive in different jenre of arts such as fashion, furniture, glass works, and jewelry works. This study illustrates and analyzes the works of four major artists who gave a specific attention to botanical motifs of Art Nouveau and applies decorative beauty of highly sophisticated and organic curved lines and the expressional forms of botanical figures to design. Art Nouveau proved this; the nature herself is as beautiful as she can be. Within Art Nouveau, the true humanism can be revitalized with the 'revival of naturality'. This study rediscovered the boundless potential of modern interpretation and application of Art Nouveau in decorative art and design.

• Journal of the HCI Society of Korea
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• v.11 no.1
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• pp.47-55
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• 2016

Three Dimensional Printing (herein, 3D printing) not only gives novelty and interests to modern people but is also a spotlighted technology that could herald a new industrial revolution. The introduction of various 3D printing service platforms has enabled individuals to easily possess products designed through 3D printing. However, there are still many issues to consider until the era of new manufacturing, when 3D printing becomes available to the general public so that anyone can make and design products with 3D printing. For instance, there needs to be sufficient consideration and research on whether the current 3D printing services can prove their higher capability to produce products conventionally done by machines and hands through 3D printing, and on the meaning of selling a wide range of product families like those of most 3D printing service platforms to the consumers. This study, which was initiated in this context, aimed to gain insight on the directions that 3D printing services need to advance going forward by letting consumers have first-hand experience on 3D printing online service platforms with a wide range of product families and those with relatively limited services, and then asking them to answer multiple-choice and short-answer survey questions on the websites they wish to purchase from, diversity of designs, design satisfaction, perceived technical skills, perceived purchase satisfaction, perceived after-sales service(A/S). As a result, we were able to witness that consumers generally had a strong preference for services with a wide range of product families (e.g. Shapeways) compared to services with a narrow range (e.g. Digital Forming). We also verified that design diversity and the possibility of realizing the designs were the crucial aspects that need to be considered with 3D printing services. Moreover, we also carried out discussions on carrying out design consulting by securing a pool of designers from diverse fields, on providing web-based designing software that can be utilized even by beginners, and on operating shops both online and offline in order to provide more competitive 3D printing services.

• Korea Science and Art Forum
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• v.37 no.1
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• pp.249-260
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• 2019

Recently, the proportion of single-person households is on the increase in Korea, expected to reach 34.6% in 2035. Among the single-person households, Young single family households are facing greater difficulties due to high house prices in Korea. The government is expanding its support to Young single family, executing various policies such as public lease housings, private lease housings for youth, youth dormitory, etc. The purpose of this study is to understand the exact housing requirement of Young single family households who have different lifestyles with other age groups and provide base line data for youth house planning which will be in use later on. Study methods are shown below. First, this research studied the status and characteristics of Young single family households by looking into literature. Second, by studying previous studies concerned with life style and housing preferences of youth, the tool for investigating preferences and needs of housing environment by Young single family households was composed. Third, survey on characterstics of space usage, preferences and needs on flat composition, and preferences of interior design were conducted based on lifestyle of Young single family-households. The survey was conducted as an online survey using SNS for 150 Young single family holds from the age of 20 and 39, including students and office workers from December 2018 to January 2019. The results are as following. (1) Looking into the space usage characteristics, considering that various activities other than basic functions take place in bedroom and living room of small-sized Young single family households, we need to consider this additionally when planning the housing. (2) Looking into the preferences and composite needs of flat composition, the subjects demand separate bed room and more living room space, and also demand expansion of living room space where various activities take place and additional storage such as dress room in bed room (3) The preferences toward interior design show preferences toward modern style and achromatic color, a representative color. The subjects also prefer floor finishing materials normally used for living spaces, and indirect, soft lighting that uses wall. Also, there are differences between interior design preferences between students (20's) and office workers(30's) due to their different lifestyles. Research is needed to propose practical residential environment requirements and plans through a case study of actual public rental housing and a wider range of users.