• International Journal of Computer Science & Network Security
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• v.23 no.4
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• pp.69-78
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• 2023

With the global rise of digital data, the uncontrolled quantity of data is susceptible to cyber warfare or cyber attacks. Therefore, it is necessary to improve cyber security systems. This research studies the behavior of malicious acts and uses Higuchi Fractal Dimension (HFD), which is a non-linear mathematical method to examine the intricacy of the behavior of these malicious acts and anomalies within the cyber physical system. The HFD algorithm was tested successfully using synthetic time series network data and validated on real-time network data, producing accurate results. It was found that the highest fractal dimension value was computed from the DoS attack time series data. Furthermore, the difference in the HFD values between the DoS attack data and the normal traffic data was the highest. The malicious network data and the non-malicious network data were successfully classified using the Receiver Operating Characteristics (ROC) method in conjunction with a scaling stationary index that helps to boost the ROC technique in classifying normal and malicious traffic. Hence, the suggested methodology may be utilized to rapidly detect the existence of abnormalities in traffic with the aim of further using other methods of cyber-attack detection.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4B
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• pp.329-334
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• 2006

The spatial variability of the L- and C- band large scale remotely sensed soil moisture data, obtained during the Southern Great Plain 1999 Experiment (SGP'99), was characterized. The results demonstrate that soil moisture data using L-band show the break in statistical symmetry (multiscaling behavior) with the variation of scale of observation, which is similar to that of the soil property such as sand content. Also, soil moisture data using C-band show single scaling behavior with the variation of scale of observation, which is similar to that of the vegetation condition. The results should be considered during downscaling the Global soil moisture data using AMSR instrument.

• Nuclear Engineering and Technology
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• v.41 no.10
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• pp.1263-1274
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• 2009

Several experimental tests to simulate a reflood phase of a cold-leg LBLOCA of the APR1400 have been performed using the ATLAS facility. This paper describes the related experimental results with respect to the thermal-hydraulic behavior in the core and the system-core interactions during the reflood phase of the cold-leg LBLOCA conditions. The present descriptions will be focused on the LB-CL-09, LB-CL-11, LB-CL-14, and LB-CL-15 tests performed using the ATLAS. The LB-CL-09 is an integral effect test with conservative boundary condition; the LB-CL-11 and -14 are integral effect tests with realistic boundary conditions, and the LB-CL-15 is a separated effect test. The objectives of these tests are to investigate the thermal-hydraulic behavior during an entire reflood phase and to provide reliable experimental data for validating the LBLOCA analysis methodology for the APR1400. The initial and boundary conditions were obtained by applying scaling ratios to the MARS simulation results for the LBLOCA scenario of the APR1400. The ECC water flow rate from the safety injection tanks and the decay heat were simulated from the start of the reflood phase. The simulated core power was controlled to be 1.2 times that of the ANS-73 decay heat curve for LB-CL-09 and 1.02 times that of the ANS-79 decay curve for LB-CL-11, -14, and -15. The simulated ECC water flow rate from the high pressure safety injection pump was 0.32 kg/s. The present experimental data showed that the cladding temperature behavior is closely related to the collapsed water level in the core and the downcomer.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.5
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• pp.397-402
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• 2020

Collagen type I is the most abundant protein in the human body. It shows viscoelastic behavior, which is what confers tendons with their viscoelastic properties. There are two different temperature setting methods in molecular dynamics simulations, namely rescaling and reassignment. The rescaling method maintains the temperature by scaling the given temperature, while the reassignment method sets the temperature according to a Maxwell distribution at the target temperature. We observed time-dependent behavior when the reassignment method was applied in tensile simulation, but not when the rescaling method was applied. Time-dependent behavior was observed only when the reassignment method was applied or when one side of the collagen molecule was stretched to a greater extent than the other side. As result, the collagen is elongated to 80nm, 100nm, 130nm, and 180nm, respectively, when the collagen is pulled by different velocities, 0.5, 1, 2, and 5 Å/ps, up to 40 Å. The results do not provide a detailed physical explanation, but the phenomena illustrated in this result are important for caution when further simulations are performed.

• The Journal of Korean Society for School & Community Health Education
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• v.9 no.1
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• pp.99-113
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• 2008

Background: School is a primary health education setting for students and the related continuous support should be provided to renovate school health education curriculum consistent to socio-cultural changes in Korean society. Objectives: This study was conducted to identify the principals' and teachers' needs and perceptions of health education topics for high school students and to analyze their conceptual map for health education curriculum in Korean high school. Methods: The sample size of the preliminary survey was 77 and that of the main survey was 276 who successfully participated in the survey among the high school teachers selected from the stratified sampling over Korea. The self-administered mailing survey was conducted to identify the factor structure of the health education topics and to analyze the conceptual properties with exploratory factor analysis and multidimensional scaling analysis in SPSS 12.0. Results: A total of 31 health education topics were generated from the preliminary survey. The five factors were determined: 'health promotion behavior and management', 'injury and sexual harassment prevention', 'bulling and aggression prevention', 'public regularity and safety perception' and 'smoking and drinking prevention'. The mean score of health education needs was between medium to high and 'public regularity and safety perception' had the highest score of education need. The two-dimensional cooperates were generated for the 31 health education topics and the two dimensional properties which divided the conceptual space were 'disease-injury' for one and 'public/environmental/individual/personal' for the other. Conclusions: Health education curriculum and its textbook should be developed considering teachers' needs and field environments for health education in every school. Therefore developing field-based health education curriculum and the textbooks should be the essential key to realize problem-solving health education for youth in real school fields.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.975-979
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• 2012

Structure and Dynamics of dilute two-dimensional (2D) ring polymer solutions are investigated by using discontinuous molecular dynamics simulations. A ring polymer and solvent molecules are modeled as a tangent-hard disc chain and hard discs, respectively. Some of solvent molecules are confined inside the 2D ring polymer unlike in 2D linear polymer solutions or three-dimensional polymer solutions. The structure and the dynamics of the 2D ring polymers change significantly with the number ($N_{in}$) of such solvent molecules inside the 2D ring polymers. The mean-squared radius of gyration ($R^2$) increases with $N_{in}$ and scales as $R{\sim}N^{\nu}$ with the scaling exponent $\nu$ that depends on $N_{in}$. When $N_{in}$ is large enough, ${\nu}{\approx}1$, which is consistent with experiments. Meanwhile, for a small $N_{in}{\approx}0.66$ and the 2D ring polymers show unexpected structure. The diffusion coefficient (D) and the rotational relaxation time ($\tau_{rot}$) are also sensitive to $N_{in}$: D decreases and $\tau$ increases sharply with $N_{in}$. D of 2D ring polymers shows a strong size-dependency, i.e., D ~ ln(L), where L is the simulation cell dimension. But the rotational diffusion and its relaxation time ($\tau_{rot}$) are not-size dependent. More interestingly, the scaling behavior of $\tau_{rot}$ also changes with $N_{in}$; for a large $N_{in}$ $\tau_{rot}{\sim}N^{2.46}$ but for a small $N_{in}$ $\tau_{rot}{\sim}N^{1.43}$.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.175-182
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• 2018

The purpose of this study was to examine the influence of factors related to whether or not to take oral examinations for 104,811 economically active population aged 25 to 54 years using the 2016 community health survey data. Multiple logistic regression analysis was performed to oral examination rate the effect general characteristics, socioeconomic and geographical characteristics, and oral health management behavior. The higher who age, the higher who education, have experience scaling, and the better who subjective oral health status, unmet dental needs rate of oral examination was higher. The higher the income level, the lower the oral examination rate. Age of economically active population, marital status, education level, area, income quartile, empolyment, scaling experience, unmet dental needs, there was a significant effect whether oral examination. The purpose of this study is to establish an positive basis for an effective oral examination program to improve accessibility to oral examinations.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.165-170
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• 1999

We have investigated the mixed-state Hall effect in HgBa$_2CaCu_2O_6$, HgBa$_2Ca_2Cu_3O_8$, and Tl$_2Ba_2Cau_2O_8$ thin films as functions of the magnetic field up to 18 T. At high fields and low temperatures, the scaling exponent in ${\rho}_{xy}$ = A${\rho}_{xx}\;^{\beta}$ shows a universal behavior, ${\beta}$ = 1 ${\pm}$ 0.1, regardless of the field, the number of CuO$_2$ layers, the types of defects, and even the types of compounds. At low fields and high temperatures, p = 1 ${\pm}$ 0.1 also appears as a universal number although the observed field range is rather limited. These observations show the universal scaling of Hall resistivity in the regions of the clean and the moderately clean limit, consistent with a theory based on the midgap states in the vortex core.

• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1611-1625
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• 2020

We propose a scaled-down experimental model of vertical air-natural convection channels by applying the modified Ishii-Kataoka scaling method with the assistance of numerical analyses to the Reactor Vault Cooling System (RVCS) of the Proto-type Gen-IV Sodium-cooled fast reactor (PGSFR) being developed in Korea. Two major non-dimensional numbers (modified Richardson and Friction number) from the momentum equation and Stanton number from the energy balance equation were identified to design the scaled-down experimental model to assimilate thermal-hydraulic behaviors of the natural convective air-cooling channel of RVCS. The ratios of the design parameters in the PGSFR RVCS between the prototype and the scaled-down model were determined by setting Richardson and Stanton number to be unity. The friction number which cannot be determined by the Ishii-Kataoka method was estimated by numerical analyses using the MARS-KS system code. The numerical analyses showed that the friction number with the form loss coefficient of 2.0 in the scale-down model would result in an acceptable prediction of the thermal-hydraulic behavior in RVCS. We also performed experimental benchmarking using the scaled-down model with the MARS-KS simulations to verify the appropriateness of the scale-down model, which demonstrated that the temperature rises and the average air flow velocity measured in the scale-down model.

• Journal of IKEEE
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• v.14 no.1
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• pp.8-16
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• 2010

This paper presents a design of the successive approximation ADC(SA-ADC) applicable to a midium-low speed analog-front end(AFE) for the maximum 15MS/s CCD image processing. SA-ADC is effective in applications ranging widely between low and mid data rates due to the large power scaling effect on the operating frequency variations in some other way of pipelined ADCs. The proposed design exhibits some distinctive features. The "differential capacitor-coupling scheme" segregates the input sampling behavior from the sub-DAC incorporating the differential input and the sub-DAC output, which prominently reduces the loading throughout the signal path. Determining the MSB(sign bit) from the held input data in advance of the data conversion period, a kind of the signed successive approximation, leads to the reduction of the sub-DAC hardware overhead by 1 bit and the conversion period by 1 cycle. Characterizing the proposed design in a 3.3 V $0.35-{\mu}m$ CMOS process by Spectre simulations verified its validity of the application to CCD analog front-ends.