• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.724-730
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• 2017

SpaceWire invented for spacecrafts has Time-Code defined for time synchronization over SpaceWire network. A Time-Code suffers transmission delay of 14[bit-period] and jitter up to 10[bit-period] whenever it passes through a SpaceWire link, which is the primary cause of time synchronization error. This work presents a simple method to improve the time synchronization which uses two extended Time-Codes. Nodes on a SpaceWire network can find how much delay and jitter a received Time-Code has suffered while it passes through the network, and they can correct time synchronization error with this information. The proposed method was validated in a simulation environment developed based on OMNeT++. The simulation result showed that time synchronization error less than a few bit-periods can be achieved. The proposed method is cost effective and suitable for small-scale SpaceWire network systems.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1993-1998
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• 2004

This paper proposes a new framework for control system design, called the data-based control approach or data space approach, in which the input and output data of a dynamical system is directly and solely used to analyze or design a control system without the employment of any mathematical models like transfer functions, state space equations, and kernel representations. Since, in this approach, most of the analysis and design processes are carried out in the domain of the data space, we introduce some notions of geometrical objects, e.g., the openloop and closed-loop data spaces, which serve as the system representations in the data space. In addition, we establish a relationship between the open-loop and closed-loop data spaces that the closed-loop data space is contained in the open-loop data space as one of its subspaces. By using this relationship, we can derive the data-based stabilization condition for a linear time-invariant discrete-time system, which leads to a linear matrix inequality with a rank constraint.

• Korean Institute of Interior Design Journal
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• no.33
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• pp.62-67
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• 2002

Architecture and Film have been interested in each other since 1895. This concern manifests various aspects and is continued up to now. If we examine into detail of relationship between film and architecture, those share the integration of time and space as the art of time and space. Film makes inexpressible time into space by showing the change of space in the issue that is the merger of time and space. Then, this is the issue of movement that compiling element was intervened. And the creative space of film which is the timely expression stimulates the person to experience whole form through spatial experience. Consequently, the architecture as an image maker must be developed through a research about film as an image creator. Also a discussion about film and architecture do not apply one to the other but must be focused on the mutual relationship.

• KIEAE Journal
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• v.14 no.4
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• pp.27-33
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• 2014

This study analyzed the electric vehicle recharging station status with recharging time limitation due to long waiting time, and figured out the user status by user interviews. And then this study verified the validity of hypothesis in terms of environmental design perspective and suggested layout of recharging station model. 21 recharging stations in Korea and station operation cases of 7 countries were examined. Except for the USA, the reality of electric vehicle recharging station today is the 1st proving stage focusing on the infrastructure construction of electric vehicle recharging station. It focuses on performance of recharging facility, use efficiency and operation environment of electric vehicle. About the effective waiting time of the user to use it should be studied. The current conditions of recharging station are as follows: Lack of independent recharging space, lack of facility that reduces external effect of recharging space, and lack of lounge for users during the waiting time. These three are essential factors constructing a suggesting model after basic layout, which needs proper measurement on the long recharging time and long waiting time. The essential factors are applied to electric vehicle recharging station layout so that users might use 'digital refresh" i.e. lounge and information contents service during the waiting time which provides convenience of recharging and emotional space with users. Such upgrade recharging station environmental model might resolve the burden of long recharging time which may contribute to the popularization of electric vehicles.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.335-338
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• 2002

For high data rate transmission over wireless fading channels, space-time trellis ceding techniques can be employed to increase the Information capacity of the communication system dramatically. In this paper, we consider the concatenated space time LDPC (Low Density Parity Check) codes. Extra ceding gains In addition to the diversity advantage is shown to be achieved for certain space-time trellis codes transmitted over quasi-static lading channels.

• Communications of the Korean Mathematical Society
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• v.37 no.3
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• pp.813-824
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• 2022

We study solitons of Kählerian Norden space-time manifolds and Bochner curvature tensor in almost pseudo symmetric Kählerian space-time manifolds. It is shown that the steady, expanding or shrinking solitons depend on different relations of energy density/isotropic pressure, the cosmological constant, and gravitational constant.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.136-141
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• 2016

This paper proposes an alternate time-switched multiplexed space-time block coding technique for orthogonal frequency division modulation systems. The traditional multiplexed space-time block coding technique can provide more data rate owing to multiple transmit and receive technique, which causes a lot of hardware burden. Alternate time-switched scheme of transmitting time-domain zeros can reduce this hardware burden by half with time-domain switches only. Simulation results show that alternate time-switched scheme has almost same performance with half of baseband and RF modules in comparison with a multiplexed space-time block coding for orthogonal frequency division modulation systems with twice repetitive transmission.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.680-684
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• 2005

This paper presents a data-based stability analysis of a MIMO linear time-invariant discrete-time system, as an extension of the previous results for a SISO system. In the MIMO case, a similar discussion as in the case of a SISO system is also applied, except that an augmented input and output space is considered whose dimension is determined in relation to both the orders of the input and output vectors and the numbers of inputs and outputs. As certain subspaces of the input and output space, both output data space and closed-loop data space are defined, which contain all the behaviors of a system, respectively, with zero input in open-loop and with a control input in closed-loop. Then, we can derive the data-based stability conditions, in which the open-loop stability can be checked by using a data matrix whose column vectors span the output data space and the closed-loop stability can also be checked by using a data matrix whose column vectors span the closed-loop data space.

• Korean Institute of Interior Design Journal
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• v.23 no.1
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• pp.96-104
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• 2014

The purpose of this study is to investigate Seonyudo Park and Kkummaru in terms of haptic space. This is also an attempt to explore temporality of appearing in architectural spaces with reference to cinematic expression in which time is visible and perceptible. The film of Chris Marker's La Jet$\acute{e}$e depicts temporal relationship by indeterminate continuum, reading the space on the disjunctive relationships of visual and auditory, and aberrance of time and space. Based on the three categories that is derived from those discussions, this study analyzes the experience of non-chronological time induced by architectural devices: the bifurcation of indeterminate circulation, the readability of space on the disjunction of visual and auditory, and the border-dismantling. Therefore, this study have a relationship with the contemporary discourse on time and events as transformation and becoming, and it means to escape from the deterministic thinking to emphasize invariability and space rather than variation and time.

• Journal of Astronomy and Space Sciences
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• v.28 no.3
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• pp.173-181
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• 2011

Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Mt. Bohyun Observatory to measure the Earth's magnetic field variations in South Korea. We, in 2007, installed a fluxgate magnetometer (RFP-523C) to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we provide the preliminary and the first statistical analysis using the BOH magnetometer installed at Mt. Bohyun Observatory. By superposed analysis, we find that daily variations of H, D, and Z shows similar tendency, that is, about 30 minutes before the meridian (11:28) a minimum appears and the time after about 3 hours and 30 minutes (15:28) a maximum appears. Also, a quiet interval start time (19:06) is near the sunset time, and a quiet interval end time (06:40) is near the sunrise time. From the sunset to the sunrise, the value of H has a nearly constant interval, that is, the sun affects the changes in H values. Seasonal variations show similar dependences to the sun. Local time variations show that noon region has the biggest variations and midnight region has the smallest variations. We compare the correlations between geomagnetic variations and activity indices as we expect the geomagnetic variation would contain the effects of geomagnetic activity variations. As a result, the correlation coefficient between H and Dst is the highest (r = 0.947), and other AL, AE, AU index and showed a high correlation. Therefore, the effects of geomagnetic storms and geomagnetic substorms might contribute to the geomagnetic changes significantly.