• Geophysics and Geophysical Exploration
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• v.26 no.4
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• pp.268-274
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• 2023

Finite source inversion is performed with a Green's function matrix and geodetic coseismic displacement. Conventionally, the Green's function matrix is constructed using the Okada model (Okada, 1985). However, for more realistic earthquake simulations, recent research has widely adopted the physics-based model, which can consider various material properties such as elasticity, viscoelasticity, and elastoplasticity. We used the physics-based software PyLith, which is suitable for earthquake modeling. However, the PyLith does not provide a mesh generator, which makes it difficult to perform finite source inversions that require numerous subfaults and observation points within the model. Therefore, in this study, we developed CPInterface (COMSOL-PyLith Interface) to improve the convenience of finite source inversion by combining the processes of creating a numerical model including sub-faults and observation points, simulating earthquake modeling, and constructing a Green's function matrix. CPInterface combines the grid generator of COMSOL with PyLith to generate the Green's function matrix automatically. CPInterface controls model and fault information with simple parameters. In addition, elastic subsurface anomalies and GPS observations can be placed flexibly in the model. CPInterface is expected to enhance the accessibility of physics-based finite source inversions by automatically generating the Green's function matrix.

• Korean Journal of Construction Engineering and Management
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• v.23 no.2
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• pp.33-44
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• 2022

The simulation function by the 4D system is a representative BIM function in the construction stage. For the 4D simulation, schedule information for each activity must be created and then linked with the 3D model. Since the 3D model created in the design stage does not consider schedule information, there are practical difficulties in the process of creating schedule information for application to the construction stage and linking the 3D model. In this study, after extracting the schedule information of the construction stage using the HDBSCAN algorithm from the 3D model in the design stage, authors propose a methodology for automatically generating schedule information by identifying precedence and sequencing relationships by applying the topological alignment algorithm. Since the generated schedule information is created based on the 3D model, it can be used as information that is automatically linked by the common parameters between the schedule and the 3D model in the 4D system, and the practical utility of the 4D system can be increased. The proposed methodology was applied to the four bridge projects to confirm the schedule information generation, and applied to the 4D system to confirm the simplification of the link process between schedule and 3D model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3708-3714
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• 2009

Recently, most of information services are provided by the computer network, since the technology of computer communication is developing rapidly, and the worth of information over the network is also increasing with expensive cost. But various attacks to quietly intercept the informations is invoked with the technology of communication developed, and then most of the financial agency currently have used OTP, which is generated by a token at a number whenever a user authenticates to a server, rather than general static password for some services. A 2-factor OTP generating method using the OTP token is mostly used by the financial agency. However, the method is vulnerable to real attacks and therefore the OTP token could be robbed and disappeared. In this paper, we propose a 3-factor OTP way using HMAC to conquer the problems and analyze the security of the proposed scheme.

• Journal of Convergence for Information Technology
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• v.9 no.10
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• pp.154-162
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• 2019

Despite the development of information and communication technology, which has a great impact on society and culture, there is no platform that provides a systematic classification and state-of-the-art information retrieval system on the traditional culture. Therefore, this paper developed a traditional culture retrieval system capable of convergence services with systematic classification and retrieval based on automatically generate and visualize the 3D timeline. This system provides the function of collecting traditional culture contents, classifying and storing collected traditional culture contents, and automatically generating 3D digital timeline based on stored traditional culture contents. In addition, a system satisfaction questionnaire was developed to evaluate the usability of the system, and 19 students participated in verifying the system. As a result of the experiment, the satisfaction of the system showed that all items were 'satisfied' on average.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.92-98
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• 2017

Generally, image contains geometrical and radiometric errors. Census transform can solve the stereo mismatching problem caused by the radiometric distortion. Since the general census transform compares center of window pixel value with neighbor pixel value, it is hard to obtain an accurate matching result when the difference of pixel value is not large. To solve that problem, we propose a census transform method that applies different 4-step weight for each pixel value difference by applying an assistance window inside the window kernel. If the current pixel value is larger than the average of assistance window pixel value, a high weight value is given. Otherwise, a low weight value is assigned to perform a differential census transform. After generating an initial disparity map using a weighted census transform and input images, the gradient information is additionally used to model a cost function for generating a final disparity map. In order to find an optimal cost value, we use guided filtering. Since the filtering is performed using the input image and the disparity image, the object boundary region can be preserved. From the experimental results, we confirm that the performance of the proposed stereo matching method is improved compare to the conventional method.

• Journal of Communications and Networks
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• v.1 no.2
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• pp.111-117
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• 1999

Using a method recently reported in the literature for analyzing the bit error probability (BEP) performance of noncoherent Mary orthogonal signals with square-law combining in the presence of independent and identically distributed Nakagami-m faded paths, we are able to reformulate this method so as to apply to a generalized fading channel in which the fading in each path need not be identically distributed nor even distributed ac-cording to the same family of distribution. The method leads to exact expressions for the BEP in the form of a finite-range integral whose integrand involves the moment generating function of the combined signal-to-noise ratio and which can therefore be readily evaluated numerically. The mathematical formalism is illustrated by applying the method to some selected numerical examples of interest showing the impact of the multipath intensity profile (MIP) as well as the fading correlation profile (FCP) on the BEP performance of M-ary orthogonal signal over Nakagami-m fading channels. Thses numerical results show that both MIP and FCP induce a non-negligible degradition in the BEP and have therefore to be taken into account for the accurate prediction of the performance of such systems.

• Journal of Internet Computing and Services
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• v.2 no.2
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• pp.105-116
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• 2001

According to increase of the factory-automation's(FA) in the field of production, the autonomous guided vehicle's(AGV) role is also increased, The study about an active and effective controller which can flexibly prepare for the changeable circumstance is in progressed. For this study. the research about ac1ion base system to evolve by itself is also being actively considered In this paper. we composed an ac1ive and effective AGV fuzzy controller to be able to do self-organization, For composing it. we tuned suboptimally membership function using genetic algorithm(GA) and improved the control efficiency by the self-correction and generating the control rules. self-organizing controlled(SOC) fuzzy controller proposed in this paper is capable of Self-organizing by using the characteristics of fuzzy controller and genetic algorithm. It intuitionally controls AGV and easily adapts to the circumstance.

• Wind and Structures
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• v.14 no.4
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• pp.337-357
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• 2011

The collection of wind speed time series by means of digital data loggers occurs in many domains, including civil engineering, environmental sciences and wind turbine technology. Since averaging intervals are often significantly larger than typical system time scales, the information lost has to be recovered in order to reconstruct the true dynamics of the system. In the present work we present a simple algorithm capable of generating a real-time wind speed time series from data logger records containing the average, maximum, and minimum values of the wind speed in a fixed interval, as well as the standard deviation. The signal is generated from a generalized random Fourier series. The spectrum can be matched to any desired theoretical or measured frequency distribution. Extreme values are specified through a postprocessing step based on the concept of constrained simulation. Applications of the algorithm to 10-min wind speed records logged at a test site at 60 m height above the ground show that the recorded 10-min values can be reproduced by the simulated time series to a high degree of accuracy.

• The KIPS Transactions:PartC
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• v.12C no.3 s.99
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• pp.323-330
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• 2005

Buffer overflow is one of the most prevalent and critical internet security vulnerabilities. Recently, various methods to prevent buffer overflow attacks have been investigated, but they are still difficult to apply to real applications due to their run-time overhead. This paper suggests an efficient rewrite method to prevent buffer-overflow attacks only with lower costs by generating a redundant copy of the return address in stack frame and comparing return address to copied return address. Not to be overwritten by the attack data the new copy will have the lower address number than local buffers have. In addition, for a safer execution environment, every vulnerable function call is transformed during the rewriting procedure.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.3-9
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• 2008

This paper is related to hair-blending for 2D virtual color hairstyler based on the semi-automatic field morphing. The proposed 2D virtual color hair-styler is characterized as generating virtual hairstyles using the variable morphing mask instead of the fixed one for the semi-automatic morphing, and then hair-blending the generated virtual hairstyles using sigmoid function around the boundary region of the variable morphing mask. The proposed method is able to generate the virtual hairstyles with an easy-to-use interface based on semi-automatic field morphing. According to the proposed method, a user can shorten the working time and even an unskilled user can obtain natural hairstyles as he or she designates a small number of external user inputs.