• Journal of KIISE:Software and Applications
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• v.35 no.1
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• pp.12-21
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• 2008

As the usage of computer systems is increasing in our lives, the reliability and safely of these systems need to be thoroughly checked through the verification techniques. As a basic formalism for several modeling methods, the finite state machine (FSM) is widely used in specification and verification of system models. And there is a technique for ing internal events of FSM in order to effectively analyze the system. However, this technique does not handle the state explosion problem since it can be applied after completely generating all the state space of the system. In this research, we provide a new approach for efficiently representing concurrent properties of FSM, the slice model and provide an efficient transition reduction method based on the slice model. Our approach is effective in time and space perspective since it is peformed by partially generating the needed system states while the existing abstraction technique can be applied to all the system states.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.6
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• pp.475-484
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• 2012

Numerical investigation is performed to understand the effects of thickness uncertainty of a supporting airfoil due to manufacturing processes on the aerodynamic characteristics of an airfoil used for measuring data in a wind tunnel testing. This is done by comparing the coefficients of lift, drag and moment of the airfoils. In this work, the airfoil model consists of three parts, one located in the center for measuring and two outer parts used for supporting. The study is carried out with a NACA64-418 airfoil and the turbulence model of Transition SST. It is found that the effect of thickness uncertainty of the airfoils used for supporting is not significant to the performance of the test airfoil at various angles of attack and Reynolds numbers.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.50.2-51
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• 2021

Stars form exclusively in cold and dense molecular clouds. To fully understand star formation processes, it is hence a key to investigate how molecular clouds form out of the surrounding diffuse atomic gas. With an aim of shedding light in the process of the atomic-to-molecular transition in the interstellar medium, we analyze Arecibo HI emission and absorption spectral pairs along with TRAO/PMO 12CO(1-0) emission spectra toward 58 lines of sight probing in and around molecular clouds in the solar neighborhood, i.e., Perseus, Taurus, and California. 12CO(1-0) is detected from 19 out of 58 lines of sight, and we report the physical properties of HI (e.g., central velocity, spin temperature, and column density) in the vicinity of CO. Our preliminary results show that the velocity difference between the cold HI (Cold Neutral Medium or CNM) and CO (median ~ 0.7 km/s) is on average more than a factor of two smaller than the velocity difference between the warm HI (Warm Neutral Medium or WNM) and CO (median ~ 1.7 km/s). In addition, we find that the CNM tends to become colder (median spin temperature ~ 43 K) and abundant (median CNM fraction ~ 0.55) as it gets closer to CO. These results hints at the evolution of the CNM in the vicinity of CO, implying a close association between the CNM and molecular gas. Finally, in order to examine the role of HI in the formation of molecular gas, we compare the observed CNM properties to the theoretical model by Bialy & Sternberg (2016), where the HI column density for the HI-to-H2 transition point is predicted as a function of density, metallicity, and UV radiation field. Our comparison shows that while the model reproduces the observations reasonably well on average, the observed CNM components with high column densities are much denser than the model prediction. Several sources of this discrepancy, e.g., missing physical and chemical ingredients in the model such as the multi-phase ISM, non-equilibrium chemistry, and turbulence, will be discussed.

• Journal of the Korea Furniture Society
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• v.22 no.3
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• pp.190-198
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• 2011

This study intended to present a new direction of differentiated and innovative furniture design for small living space overcoming the uniformity of conventional small living. In order to achieve these goals, a new piece of furniture with multi functions useful for such small space has been designed and explained in this study. This new type multi-functional furniture can be utilized as kitchen, dining table, home bar or office stand depending on the user's necessity. In particular, it provides more adaptability to changing life and spatial availabilities for small living space in terms of space division, separation and fusion features. Based on the needs of small living space brought by social changes, the conventional concept of small living space, which divides space by partitions or walls, should be changed into flexible perception of space. Also, this research proposed the features of furniture design for functional shifts in terms of its functional, structural, and systematical aspects. In this respect, space can be regarded as a variable place and the image of space can be differently appreciated by means of shift, functional transition and mobility. That is, small living space can be perceived as kitchen, living space or working space at the same time. In conclusion, the versatile use of limited space can be a solution to the issues related to small living space; the convertible and movable furniture called F4 Island presented in this study can transform such spatially limited space into a space with multiple functions to meet the requirements of its residents.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.11
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• pp.145-156
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• 2018

Urban campus, one of the main urban facilities, is the representative place that is struggling with 'gridlock'. Due to privatization of space among different departments and space shortages, gridlock has been occurring as a result. The urban campus trying to solve this problem by changing the quality of space, especially the structure of the shared space, which is expected to be the solution to the grid lock problem. The main purpose of this study is to investigate the structural change in the university's shared space based on paradigm transition. The theoretical consideration is to analyze the spatial characteristics of university shared space that appear at different stages through a new perspective that compares the gridlock phenomenon and the shared paradigm. The framework of the analysis of the shared space, which has recently been restructured, is classified into the spatial characteristics of collaborative space, the creative space, and the common/complex space. In addition, these spatial characteristics are again analyzed through the division of legislative facility classification, management governance subject, area, building location and layout, exposure to the outside as well as the analysis of student and staff entry and exit, sharing structure of site and space, and the classification of program characteristics. The results are as follows: The restructured space is systemized so that the management governance of each space would be connected to each other to share information and space. Furthermore, the spatial boundary between colleges or between campus spaces are not only physically, but categorically clear. The restructured space has semi (or in-between)-spatial characteristics such as the intersection in inside and outside of the pedestrian's circulation and the mixture of programs. This study could serve as principal references in presenting the systematic analysis of directions of the shared spatial structure for the urban campus where new educational space is required due to the changes in the university system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.4
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• pp.311-321
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• 2020

With the recent breakthrough in technology for micro-satellite, small satellite, and mega constellation missions, and the cost of accessing space from recycled space launch vehicles sharply lowered. Thus, space development is set to make a transition to a new space age that is different from before. Accordingly, the problem of worsening space environment conditions due to the increase in space debris, an inevitable adjunct to active space development, is also emerging as an international concern. In this paper, the contents and trends of international organizations for the protection of the space environment and space debris mitigation guidelines of each country were reviewed and forecast the future movement of the international community. In addition, it is suggested example of guidelines that fit the reality of Korea and how to apply them.

• Korean Institute of Interior Design Journal
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• v.21 no.1
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• pp.103-110
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• 2012

With a theoretical focus on the emotional experiences created via the interface, and the relationship between human beings and space, this study aims to corroborate and clarify the formation and verification of emotional interactions between human beings and space using body movements. It follows the method of Coining "Movement Phrases" through the analysis of body movements in the experimental space, thereby developing them into a complete scenario to produce the story of emotional expression. This study has hereby generated the following outcomes: First, the "pocket-type" exhibition displays a higher frequency of body movements than the "general" exhibition. It has close connections with emotional vocabularies: "Curious," "interesting," "warm," and "fun." The "general" exhibition records a relatively high frequency of emotional vocabularies like "natural," "efficient," and "free." Second, it is possible to analyze the story of space using a scenario, just like drama, based upon attributes and serial relationships. The "exposition" section reveals a high degree of "curiosity" and a large number of body movements, while the "development" section indicates high degree of "surprise" plus slight body movements. The "transition" sections manifest high "interest" and many body movements, and the "climax" section shows a high frequency of "surprise" and many changes in body movements. The "conclusion" section finally invokes images together with body movements.

• Korean Institute of Interior Design Journal
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• v.19 no.5
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• pp.56-66
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• 2010

This study proposes a thesis of architectural concepts and visual dimension systems, and the comparison between steps of spatial formation and dimensional alteration. The second chapter, to form the basis of this study, explains the dimensional alterations and changes of fundamental notion of space. In the third chapter, history of space, architectural formations, and changes of the viewpoint are analyzed as objects of study. The forth chapter presents the interrelation between dimensional alteration and the transition in fundamental notion of space, demonstrating that modern architecture has been born from these cultural movements. Lastly, the fifth chapter suggests possibilities on further studies and the following conclusions: First, architectural spaces have been changed, in accordance with the changes of culture, art and the tools that regulate architectural design. Proportional regulations by two-dimensional tools and depth through three-dimensional drawings are created. Second, architectural spaces gained depth by recognizing movement and time that have induced formations to change, creating various aesthetic backgrounds and attempts. Third, the aesthetic background and cosmologic spatial concept have led the visualization and changes of architectural experience. It created the design tools and shapes originated in dynamism and vitality. Forth, diversification of fundamental spatial concepts has become palimpsest and complex, and been divided into four dimensions; expressional two-dimensional space, perspective three-dimensional space, forth-dimensional space of time and experience, and imagery space formed by body movement. Fifth, architecture has been influenced by the elevated viewpoint that understands the whole world as a space. It has evolved from the two-dimensional proportion principle, change of depth and vanishing point to multidimensional space of movement and time. Sixth, changes of fundamental notion of space have arisen from changes of visual dimensions in times. In other words, space has been developed from two-dimensional space to multidimensional space by accepting visual dimension, grasping distance, direction, depth, height, velocity, movement, gravity, power and structure.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.109-114
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• 2013

The biological active points (BAP) are known as low resistance spots or good electro-permeable points. In this paper, a new method for BAP detection using the bio-impedance measurement system based on the adaptive frequency tracking filter (AFTF) and the transition event detector is presented. Also, the microcontroller process continuous time demodulation of the modulated signal by multi frequency components using the AFTF. The transition event detector based on the phase space method is applied about each frequency using the BAP equivalent model which is proposed.

• Journal of Welding and Joining
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• v.20 no.4
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• pp.510-516
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• 2002

Recently the laser welding technology has been applied increasingly for the automotive bodies. But the lap joint laser welding for 3 dimensional automotive body is new while the butt joint laser welding is well known as the tailored blank technology. In this study, the process window was found for the full penetration welding of the lap joint of the 1mm-thick high strength steel sheets. The limit curves and characteristic curves were suggested to define the boundaries and the contour lines in a space of the welding speed and the gap size. The characteristics of the weld sectional geometry were used to determine the limit curves. They are bead width, penetration depth and sectional area. After the observed data was analysed carefully, it was noticed that there was a transition point at which the sectional shape was changed and the bead area jumped as the welding speed was increased. Also a new concept of 'input energy Per volume' was suggested to distinguish the difference at the transition Point. The difference of sectional areas at the transition point can be related to the dynamic keyhole phenomena.