• Journal of the Korea Society of Computer and Information
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• v.5 no.3
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• pp.215-219
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• 2000

The purpose of this paper is to propose a method to maximize the efficiency of a content-based image retrieval for various kinds of images. This paper discuss the self-adaptivity for the change of image domain and the self-selection of optimal features for query image, and present the efficient method to maximize content-based retrieval for various kinds of images. In this method, a content-based retrieval system is adopted to select automatically distinctive feature patterns which have a maximum efficiency of image retrieval in various kinds of images. Experimental results show that the Proposed method is improved 3% than the method using individual features.

• Journal of IKEEE
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• v.28 no.3
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• pp.253-260
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• 2024

In this paper, we propose an ⲉ-PID controller for the altitude control of the quadrotor from the ground by considering the mass of the AR Drone and external disturbance. The first part consists of modeling the quadrotor and carrying out the system analysis with the proposed controller and the second part consists of carrying out the experiment in the lab to show that our control method along with the analysis coincides with the experiment.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.277-280
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• 2005

With the proliferation of mobile terminals, use of the Internet in mobile environments is becoming more common. To support mobility in these terminals, Mobile IPv4 is proposed and represents the standard in IPv4 environments. Authentication should be mandatory, because mobile terminals can utilize Internet services in any foreign domain. Mobile IPv4 provides symmetric key based authentication using the default HMAC-MD5. However, symmetric key based authentication creates a key distribution problem. To solve this problem, public key based authentication mechanisms have been proposed. In this paper, the performance of each of these mechanisms is evaluated. The results present that, among these mechanisms, partial certificate based authentication has superior performance, and certificate based authentication has the worst performance. Although current public key based authentication mechanisms have lower performance than symmetric key based authentication, this paper presents the possibility that public key based authentication mechanisms may be used for future mobile terminal authentication.

• Electronics and Telecommunications Trends
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• v.37 no.1
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• pp.21-31
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• 2022

Human behavior and emotions are influenced by experiences accumulated through the past and present. To realize artificial intelligence technology that understands and sympathizes with humans, cognitive computing technology that automatically analyzes human behaviors, habits, and emotions associated with specific situations and uses past data and domain knowledge is required. In this study, we examine the latest research trends on human-understanding cognitive computing technology that recognizes human behavior and emotions, stores them as experience data, and provides services by analyzing the stored data. Further, we introduce high-quality data collection research in real-life and services for improving physical and mental health. We also review key issues essential for developing these technologies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.3
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• pp.231-238
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• 2020

This paper investigates the soundness of porcelain insulators associated with the acoustic emission (AE) technique. The AE technique is a popular non-destructive method that measures and analyzes the burst energy that occurs mainly when a crack occurs in a high-frequency region. Typical AE methods require continuous monitoring with frequent sensor calibration. However, in this study, the AE technique excites a porcelain insulator using only an impact hammer, and it applies a high-pass filter to the signal frequency range measured only in the AE sensor by comparing the AE and the acceleration sensors. Next, the extracted time-domain signal is analyzed for the damage assessment. In normal signals, the duration is about 2ms, the area of the envelope is about 1,000, and the number of counts is about 20. In the damage signal, the duration exceeds 5ms, the area of the envelope is about 2,000, and the number of counts exceeds 40. In addition, various characteristics in the time and frequency domain for normal and damage cases are analyzed using the short-time Fourier transform (STFT). Based on the results of the STFT analysis, the maximum energy of a normal specimen is less than 0.02, while in the case of the damage specimen, it exceeds 0.02. The extracted high-frequency components can present dynamic behavior of crack regions and eigenmodes of the isolated insulator parts, but the presence, size, and distribution of cracks can be predicted indirectly. In this regard, the characteristics of the surface crack region were derived in this study.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.1
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• pp.25-35
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• 2023

Considering the non-linear behavior of structure and soil when evaluating a nuclear power plant's seismic safety under a beyond-design basis earthquake is essential. In order to obtain the nonlinear response of a nuclear power plant structure, a time-domain SSI analysis method that considers the nonlinearity of soil and structure and the nonlinear Soil-Structure Interaction (SSI) effect is necessary. The Boundary Reaction Method (BRM) is a time-domain SSI analysis method. The BRM can be applied effectively with a Perfectly Matched Layer (PML), which is an effective energy absorbing boundary condition. The BRM has a characteristic that the magnitude of the response in far-field soil increases as the boundary interface of the effective seismic load moves outward. In addition, the PML has poor absorption performance of low-frequency waves. For this reason, the accuracy of the low-frequency response may be degraded when analyzing the combination of the BRM and the PML. In this study, the accuracy of the analysis response was improved by adjusting the PML input parameters to improve this problem. The accuracy of the response was evaluated by using the analysis response using KIESSI-3D, a frequency domain SSI analysis program, as a reference solution. As a result of the analysis applying the optimal PML parameter, the average error rate of the acceleration response spectrum for 9 degrees of freedom of the structure was 3.40%, which was highly similar to the reference result. In addition, time-domain nonlinear SSI analysis was performed with the soil's nonlinearity to show this study's applicability. As a result of nonlinear SSI analysis, plastic deformation was concentrated in the soil around the foundation. The analysis results found that the analysis method combining BRM and PML can be effectively applied to the seismic response analysis of nuclear power plant structures.

• Archives of Pharmacal Research
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• v.23 no.6
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• pp.633-636
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• 2000

Translationally controlled tumor protein (TCTP), also known as IgE-dependent histamine-releasing factor, is a growth-related tumor protein. Although the primary sequence of rat TCTP does not reveal any recognizable $Ca^{2+}$ -binding motif, previous studies have demonstrated that rat TCTP consisting of 172 amino acids is a $Ca^{2+}$ -binding protein. However. the region of TCTP required for $Ca^{2+}$ interaction has not been mapped to the molecule. Here, we reported that the $Ca^{2+}$ binding region of TCTP which was mapped by using a combination of deletion constructs of rat TCTP and $^{45}Ca^{2+}$-overlay assay. was confined to amino acid residues 81-112. This binding domain did not show any peculiar loop of calcium- binding motif such as CaLB domain and EF hand motif and it seems to be constituted of random coil regions neighboring the a helix. Thus, our data confirm that TCTP is a novel family of $Ca^{2+}$ -binding protein.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.443-448
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• 2008

Multidomain proteins for the biochemical analysis of the scouring efficiency of cotton fabrics were constructed by the fusion of a reporter moiety in the N-terminal and the cellulose binding domain (CBD) in the C-terminal. Based on the specific binding of the CBD of Cellulomonas fimi exoglucanase (Cex) to crystalline cellulose (Avicel), the reporter protein is guided to the cellulose fibers that are increasingly exposed as the scouring process proceeds. Among the tested reporter proteins, a thermostable ${\beta}$-glycosidase (BglA) from Thermus caldophilus was found to be most appropriate, showing a higher applicability and stability than GFP, DsRed2, or a tetrameric ${\beta}$-glycosidase (GUS) from Escherichia coli, which were precipitated more seriously during the expression and purification steps. When cotton fabrics with different scouring levels were treated with the BglA-CBD and incubated with X-Gal as the chromogenic substrate, an indigo color became visible within 2 h, and the color depth changed according to the conditions and extent of the scouring.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.67.1-67.1
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• 2015

In the past two decades, diverse methods and computer codes for reconstruction of coronal magnetic fields have been developed. Some of them can reproduce a known analytic solution quite well when the magnetic field vector is fully specified by the known solution at the domain boundaries. In practical problems, however, we do not know the boundary conditions in the computational domain except the photospheric boundary, where vector magnetogram data are provided. We have developed a new, simple variational method employing vector potentials. We have tested the computational code based on this method for problems with known solutions and those with actual photospheric data. When solutions are fully given at all boundaries, the accuracy of our method is almost comparable to best performing methods in the market. When magnetic field vectors are only given at the photospheric boundary, our method excels other methods in "figures of merit" devised by Schrijver et al. (2006). Our method is expected to contribute to the real time monitoring of the sun required for future space weather prediction.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.2
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• pp.10-18
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• 2001

The very large floating structure which can be used for as airport may be as large as several kilometer long and wide. The first order wave forces as well as wave drift forces are very important forces on such a very large floating structures. In the present study, the time simulation of motion responses for dolphin-moored VLFS in waves is presented. The hydrodynamic coefficients and wave forces involved in the equations are obtained from a three-dimensional panel method in the frequency domain. The horizontal drift forces and mooring forces for dolphin systems are taken into account. As for numerical example, time domain analyses are carried out for a VLFS(Phase I) in irregular wave condition.