• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.3
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• pp.264-269
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• 2013

This paper is to investigate propagation path characteristics of GPS potential jamming signal. To do this, the spherical ground diffraction model is applied to the potential jamming scenario referred to the GPS jamming events occurred in recent years. The fundamental theory on the propagation path loss is discussed and a specific model is applied to several vehicles types which have own heights of antennas in order to compare their propagation path loss values at same 2-D location. The transmitting powers are appropriately given as the ordinary GPS jamming events. And then the received powers in dBW are obtained with given transmitting powers and the estimated total loss. The result of received jamming power at various locations due to the given scenario was distinct. For example, propagation loss values were estimated as -147 ~ -142dBW and -167 ~ -162dBW in $10^6W$ and $10^4W$, respectively. This computation result of the loss can be seriously considered with the tolerable jammer power against L1- C/A GPS receiver under any real jamming situations.

• Earthquakes and Structures
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• v.12 no.3
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• pp.359-374
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• 2017

The seismic events in Northern Italy, May 2012, have revealed the seismic vulnerability of typical Italian precast industrial buildings. The aim of this paper is to present a seismic fragility model for Italian RC precast buildings, to be used in earthquake loss estimation and seismic risk assessment by comparing two building typologies and three different codes: D.M. 3-03-1975, D.M. 16-01-1996 and current Italian building code that has been released in 2008. Based on geometric characteristics and design procedure applied, ten different building classes were identified. A Monte Carlo simulation was performed for each building class in order to generate the building stock used for the development of fragility curves trough analytical method. The probabilistic distributions of geometry were mainly obtained from data collected from 650 field surveys, while the material properties were deduced from the code in place at the time of construction or from expert opinion. The structures were modelled in 2D frameworks; since the past seismic events have identified the beam-column connection as the weakest element of precast buildings, two different modelling solutions were adopted to develop fragility curves: a simple model with post processing required to detect connection collapse and an innovative modelling solution able to reproduce the real behaviour of the connection during the analysis. Fragility curves were derived using both nonlinear static and dynamic analysis.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.30-37
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• 2010

The purpose of this study is to analyze the architectural publicness of Hague city hall by Richard Meier. The Hague city hall shows the systematic and comprehensive configuration of architectural publicness. Meier applied publicness to the city hall from concept and the configuration of space to object design. Architectural publicness of Hague city hall can be realized by providing large public space including atrium, programs about public events, linear space for street activities and the lower location of public facilities in the city hall without the limitation of weather, lime and size of space. Architectural publicness can obtain its real meaning when physical conditions meet the standard of public activities. Besides this, the Hague city hall case shows the desirable role model of city administrator and NGOs in that public events are organized by the independent body. The publicness of architecture is influenced by various factors including physical and political systems. The case study of the architectural publicness is very important in that it is very hard to generalize. In these basis, the study for architectural publicness can be complemented by concrete and positive case studies as well as existing humane and general studies.

• The Journal of the Korea Contents Association
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• v.7 no.10
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• pp.27-35
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• 2007

Radio Frequency Identification(RFID) technology is set to play an essential role in object tracking or supply chain management systems. New challenges for RFID data management are needed in the RFID applications. RFID data are generated quickly and automatically, and can be used for object tracking, or for real-time monitoring. These applications are mostly associated with the timestamps when the events happen. In this paper, we propose a temporal RFID data model to maintain the history of events and state changes and to monitor the states of RFID objects. Also we propose data filtering method of non active data based on temporal RFID data model. This data model involves essential basic operations for RFID data. We show increased query performance through the data filtering method of non active data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.12
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• pp.2303-2310
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• 2009

Defense systems are needed to prevent catastrophic failures of a power grid due to cascaded events. Cascaded events can be attributed to improper operations of protective relays. Especially, it is the most dangerous problem that trips of backup relays by overload. In this paper, a new algorithm of predicting Zone 3 acting time of distance relay is proposed using the real time synchronized data from PMUs on the transmission system when the power system is danger. In the proposed, some part of the power system are outage when some unexpected fault in the power system, the algorithm will monitor the impedance locus of distance relay. At this time, if there is a big change of Impedance locus, the algorithm will calculate the Zone 3 acting time of the distance relay by the over load. In the case studies, the estimation and simulation network have been testified and analysed in Matlab Simulink.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.107-114
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• 2010

A nonlinear story is generated through the interactivity with users using the interactive storytelling system. In a play or movie, audiences can watch one scene at a time, and in order to watch next scene, they should wait for the end of current scene. In the real world, however, various events can simultaneously happen at different places, and even those events performed by characters may dramatically affect the flow of the story. This paper suggests Constraint Based narrative structure to create such story, known as "Simultaneous Story Arcs", and "Multi Viewpoint" to simultaneously lead the direction of the stories in each place.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.45-53
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• 2020

Past literatures have not studied the impact of real-world events or information on the return and volatility of virtual currencies, particularly on the COVID-19 event, day-of-the-week effect, daily high-low price spreads and information flow rate. The study uses the ARMA-GARCH model to capture Bitcoin's return and conditional volatility, and explores the impact of information flow rate on conditional volatility in the Bitcoin market based on the Mixture Distribution Hypothesis (Clark, 1973). There were 3,064 samples collected during the period from 1^st of January 2012 to 20^th April, 2020. Empirical results show that in the Bitcoin market, a daily high-low price spread has a significant inverse relationship for daily return, and information flow rate has a significant positive relationship for condition volatility. The study supports a significant negative relationship between information asymmetry and daily return, and there is a significant positive relationship between daily trading volume and condition volatility. When Bitcoin trades on Saturday & Sunday, there is a significant reverse relationship for conditional volatility and there exists a day-of-the-week volatility effect. Under the impact of COVID-19 event, Bitcoin's condition volatility has increased significantly, indicating the risk of price changes. Finally, the Bitcoin's return has no impact on COVID-19 events and holidays (Saturday & Sunday).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.803-808
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• 2010

Wireless Sensor Networks are widely applied for organizing real-time monitoring systems. Unlike general kinds of sensor networks, it is important to preferential send emergency data to the control server when urgent events are occurred. But IEEE 802.15.4 MAC protocol which is generally deployed for wireless sensor network does not support algorithm for urgency data handling. Therefore, we proposed a MAC protocol which consider the priority for the urgency data handling.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.78.2-78.2
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• 2012

We have studied how the intergalactic magnetic field (IGMF) affects the propagation of super-GZK iron nuclei that originate from extragalactic sources within the local GZK sphere. Toward this end, we set up hypothetical sources of ultra-high-energy cosmic-rays (UHECRs), virtual observers, and the magnetized cosmic web in a model universe constructed from cosmological structure formation simulations. We then arranged a set of reference objects at high density region to represent astronomical objects formed in the large scale structure (LSS). With our model IGMF, the paths of UHE iron nuclei are deflected on average by about 70 degrees, which might indicate a nearly isotropic distribution of arrival directions. However, the separation angle between the arrival directions and the nearest reference object on the LSS is only ~6 degrees, which is twice the mean distance to the nearest neighbors among the reference objects. This means that the positional correlation of observed UHE iron events with their true sources would be erased by the IGMF, but the correlation with the LSS itself is to be sustained. We discuss implications of our findings for correlations studies of real UHECR events.