• Journal of The Korean Astronomical Society
• /
• 제37권4호
• /
• pp.151-157
• /
• 2004

It is investigated quantitative relations between the magnetic storm magnitude and the solar wind parameters such as the Interplanetary Magnetic Field (hereinafter, IMF) magnitude (B), the southward component of IMF (Bz), and the dynamic pressure during the main phase of the magnetic storm with focus on the role of the interplanetary shock (hereinafter, IPS) in order to build the space weather fore-casting model in the future capable to predict the occurrence of the magnetic storm and its magnitude quantitatively. Total 113 moderate and intense magnetic storms and 189 forward IPSs are selected for four years from 1998 to 2001. The results agree with the general consensus that solar wind parameter, especially, Bz component in the shocked gas region plays the most important role in generating storms (Tsurutani and Gonzales, 1997). However, we found that the correlations between the solar wind parameters and the magnetic storm magnitude are higher in case the storm happens after the IPS passing than in case the storm occurs without any IPS influence. The correlation coefficients of B and $BZ_(min)$ are specially over 0.8 while the magnetic storms are driven by IPSs. Even though recently a Dst prediction model based on the real time solar wind data (Temerin and Li, 2002) is made, our correlation test results would be supplementary in estimating the prediction error of such kind of model and in improving the model by using the different fitting parameters in cases associated with IPS or not associated with IPS rather than single fitting parameter in the current model.

• Korean Journal of Applied Biomechanics
• /
• 제31권2호
• /
• pp.140-147
• /
• 2021

Objective: The purpose of this study is to identify the mechanism of changes in maximum voluntary torque with the magnitude and duration of pre-activation torque during voluntary isometric knee extension. Method: 11 male subjects (age: 25.91±2.43 yrs., height: 173.12±3.51 cm, weight: 76.45±7.74 kg) participated in this study. The subjects were required to produce maximal voluntary isometric torque with a particular pre-activation torque condition. The properties of pre-activation torque consisted of the combinations of 1) three levels of magnitude, e.g., 32 Nm, 64 Nm, 96 Nm, and 2) two levels of duration, e.g., 1 sec, and 3 sec; thus, a total of six conditions were given to the subjects. The force and EMG data were measured using the force transducers and wireless EMG sensor, respectively. Results: The results showed that the maximum voluntary torque increased the most with relatively large and fast (96 Nm, 1 sec) pre-activation condition. Similarly, with relatively large and fast (96 Nm, 1 sec) preactivation, it was found that the integrated EMG (iEMG) of the agonist muscles increased, while no significant changes in the co-contraction of the antagonist muscles for the knee extension. Also, the effect of pre-activation conditions on the rate of torque development was not statistically significant. Conclusion: The current findings suggest that relatively larger in magnitude and shorter in duration as the properties of pre-activation lead to a larger magnitude of maximal voluntary torque, possibly due to the increased activity of the agonist muscles during knee extension.

• Tunnel and Underground Space
• /
• 제32권3호
• /
• pp.203-218
• /
• 2022

A hydro-mechanical study was performed to analyze the relationship between the magnitude of injection-induced seismicity and shut-in. In hydraulic analysis, the suspension of fluid injection makes the pore pressure gradient smaller while the pore pressure at the pressure front can reach the critical value for several hours after shut-in, which leads to the additional slip with wider area than during injection. The hydro-mechanical numerical analysis was performed to model the simplified fault system, and simulated the largest magnitude earthquake during shut-in stage. The effect of the abrupt suspension of fluid injection on the large magnitude earthquake was investigated in comparison with the continuous injection. In addition to the pore pressure distribution, it was found that the geometry of multiple faults and the stress redistribution are also important in evaluating the magnitude of the induced seismicity.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
• /
• pp.33-40
• /
• 2000

The assessment of earthquake hazards involved consideration of earthquake magnitude, frequency, last movement and probability of occurrence. The appraisal of earthquake potential is feasible because historical data show a good correlation between earthquake size and the fault rupture parameters of length, displacement, and area. Additionally, the characteristics of fault behavior should be considered to evaluate the earthquake potential magnitude. In this study, in order to evaluate the earth quake potential by the fault behavioral patterns, based on the experimental background which the geometric characteristics of the individual domains, such as strike, width, fault tip patterns, and orientation of secondary shears reflect sliding behavioral patterns in each section, the straight sections of A, D and E domains were examined to the creeping section of stably sliding. In contrast, the curved section of B domain was examined to the locked section of stick-slip movement. These results of studies can be applied to evaluate the earthquake potential magnitude from the fault structural parameters.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• 제19권10호
• /
• pp.1894-1899
• /
• 1994

In this paper, a new identification method is proposed for unknown digitally modulated input signals. The proposed identification method is implemented using a self-organized neural network which is based on the characteristic features of the symbol magnitude; the number of symbol magnitude levels, amplitude probability density and adjacent symbol magnitude ratio. The proposed method was performed for 5 QAM signals. The simulation results show that the self-organized neural network can accurately recognize all kinds of patterns even at SNR 8dB. The proposed method can be applied to the intelligent communication system on ISDN and multi-point polling networks.

• Journal of the Ergonomics Society of Korea
• /
• 제12권2호
• /
• pp.3-13
• /
• 1993

A psychophysical measurement technique called "magnitude estimation" was used to evaluate several interior design alternatives for a high speed train. Pas- senger activity, seat direction, and passenger age were manipulated by using a three factor within-subjects experimental design. During the experiment, two dependent measures, a line length and a numerical estimate for each alternative design were collected to validate the experimental procedures. The results showed that pasnger seats arranged in the same direction as the running direction of the train was favored nine times more than the opposite. Also, the subjects preferred listening to music in a coach train to the other activities such as reading newspaper, watching a movie, and resting. This paper demonstrates that a psychophysical technique can be sued in the design of a development process, especially when it is difficult to quantify design variables such as subjective opinion or preference, etc.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 한국지진공학회 2002년도 춘계 학술발표회 논문집
• /
• pp.169-176
• /
• 2002

It was performed that the seismic response analysis using seismic magnitude and concrete dam type(Model-1, Model-2) on dynamic behavior properties of concrete dam. As a results of each seismic magnitude acted on concrete dam, the maximum response acceleration at dam crest was amplified about 3, 5-4 times and maximum displacement and stress at dam crest of Model-2 was larger than Model-1. So, it can be recommended that codified-seismic coefficient method is proper in case of seismic design of concrete dam and Model-1 is better than Model 2 in consideration of stability in displacement and stress of design of concrete dam.

• Proceedings of the KSME Conference
• /
• 대한기계학회 2001년도 춘계학술대회논문집E
• /
• pp.317-322
• /
• 2001

This study depicts an experimental work of the impulsive wave discharged from the open end of several kinds of right-angle bend pipes, which are attached to the open end of a simple shock tube. The weak normal shock wave with its magnitude of Mach number from 1.03 to 1.20 is employed to obtain the impulsive wave propagating outside the open end of the bend pipes. The experimental data of the magnitude of the impulsive wave and its propagation directivity are analyzed to characterize the impulsive waves discharged from the right-angle bend pipes and compared with those from a straight pipe. The results obtained show that a right-angle miter bend considerably reduces the magnitude of the impulsive wave and its directivity toward to the pipe axis, compared with the straight pipe. It is believed that the right angle miter bend pipe can playa role of passive control against the impulsive wave.

• Proceedings of the IEEK Conference
• /
• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
• /
• pp.371-374
• /
• 2000

We propose an efficient method for content-based ultrasound image retrieval using magnitude frequency spectra and implement a retrieval system based on the proposed method. The target images are ultrasound images of adult organs. Trained users often acquire such images so that images of the same kind of organs are very similar, although their locations may not exactly coincide. Therefore, the magnitude frequency spectrum, which has a translation-invariant property, is used as a feature. All the object images in the image DB is pre-classified in the same kind organs. Experimental results show that the proposed method is superior to some well-known conventional methods.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제11권4호
• /
• pp.293-298
• /
• 2011

In this paper, we propose a new image descriptor, that is, a rotation invariant histogram of oriented gradients (RIHOG). RIHOG overcomes a disadvantage of the histogram of oriented gradients (HOG), which is very sensitive to image rotation. The HOG only uses magnitude values of a pixel without considering neighboring pixels. The RIHOG uses the accumulated relative magnitude values of corresponding relative orientation calculated with neighboring pixels, which has an effect on reducing the sensitivity to image rotation. The performance of RIHOG is verified via the index of classification and classification of Brodatz texture data.