• The Journal of Sustainable Design and Educational Environment Research
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• v.11 no.1
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• pp.23-31
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• 2012

The number of school crime has grown continuously for last ten years and its intensity also has reached to serious condition. The concept of CPTED(Crime Prevention through Environmental Design) needs to be focused for improving school environment regarding this context. The exterior space of school environment is variously exposed to school crimes committed by colleague students and also intruders. From the perspective of school CPTED, Natural surveillance as one of the practical strategies requires the micro-scale analysis which clarifies local visibility at each different school exterior space. Thus, the purpose of this research is to develop the analysis method clarifying visibility condition at exterior space of school environment, which supports finding the condition of natural surveillance. The programmed analysis algorithm generated quantitative results clarifying Degree for static visibility and Clustering Coefficient for user tracking visibility. The result of this study produced the analysis method feasible to clarify weak natural surveillance conditions at school exterior spaces. Also, it is expected that the developed analysis method will be used to improve the layout of school exterior space from the perspective of CPTED.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.11
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• pp.23-32
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• 2018

The purpose of this study is to establish a walking energy weighted ERAM model that can predict the pedestrian volume by the connection structure of the vertical and horizontal spaces within a three-dimensional building. The process of building a walking-energy weighted ERAM model is as follows. First, the spatial graph was used to reproduce three-dimensional buildings with vertical and horizontal spatial connection structures. Second, the walking energy was measured on the spatial graph. Third, ERAM model was used to apply weights with spatial connection properties in random walking environment, and the walking energy weights were applied to the ERAM model to calculate the walk energy weighted ERAM values and visualize the distribution of pedestrian flow. To verify the validation of the established model, existing and proposed spatial analysis models were compared to real space. The results of this study are as follows : The model proposed in this study showed as much elaborated estimation of pedestrian traffic flow in real space as in traditional spatial analysis models, and also it showed much higher level of forecasting pedestrian traffic flow in real space than existing models.

• Journal of Broadcast Engineering
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• v.15 no.3
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• pp.414-425
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• 2010

When we implement the single frequency network (SFN) in ATSC terrestrial DTV system, there is an interference problem to DTV receivers due to the use of same frequency channel among transmitters and repeaters. To resolve this problem, it is recommended to adopt the transmitter identification signals in transmitting equipments. In this paper, we analyzed the influence suffered by legacy DTV receivers when the TxID signal is added to the DTV transmitting signals and the results were further verified by computer simulation, laboratory test and field test. The above tests show that if the TxID signal is added to the level of -30dB compared to the original DTV signal, the TOV(Threshold Of Visibility) increment in legacy receivers is about 0.17 dB. It means that we can insert and transmit the TxID signal in ATSC terrestrial DTV system without making the negative effect to the legacy DTV receivers.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.49.2-49.2
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• 2016

The number of discovery of asteroids with peculiar rotational states has recently increased, and hence a novel approach for lightcurve analysis is considered to be critical. In order to investigate objects such as Non-Principal Axis (NPA) rotator, we selected a NPA candidate, (5247) Kryolv as our target considering its Principal Axis Rotation (PAR) code and the visibility in early 2016. The observations of Krylov were made using Korea Microlensing Telescope Network (KMTNet) 1.6 m telescopes installed at the three southern sites with TO (Target of Opportunity) observation mode. We conducted R-band time-series photometry over a total of 51 nights from January to April 2016 with several exposures during each allocated run. The ensemble normalization photometry was employed using the AAVSO Photomtric All-Sky Survey (APASS) catalog for the standardization. We successfully confirmed its NPA spin state based on the deviation from the reduced lightcurve, and thus Krylov is recorded as the first NPA rotator of its kind in the main-belt, with its precession and rotation periods, $P{\varphi}=81.18h$ and $P_{\Psi}=67.17h$, respectively. In this paper, we present the spin direction, the 3D shape model and taxonomy of the newly confirmed NPA asteroid (5247) Krylov.