• Journal of the Korean Society for Nondestructive Testing
• /
• v.18 no.3
• /
• pp.172-180
• /
• 1998

It is attempted to verify the Quantitative relationship between fracture mechanical parameters (${\Delta}K$, $K_{max}$) and X-ray parameters (residual stress, half-value breadth) of A12009-15v/o $SiC_w$ composite, and normalized SS41 steel. In this study, fatigue crack propagation test were carried out and X-ray diffraction was applied to fatigue fractured surface in order to investigate the change of residual stress and half-value breadth on fatigue fractured surface. And it is loaded prestrain to each tensile specimen, A12009-15v/o $SiC_w$ composite(0.3, 0.5, 1, 1.5, 2%) and normalized SS41 steel(0.63, 2.25, 7.50, 13.7, 20%), for investigating plastic strain rate using nondestructive measurement method. X-ray diffraction was applied to the prestrained tensile specimens in order to measure the change of residual stress and half-value breadth.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.13 no.1
• /
• pp.25-37
• /
• 1993

This paper describes the use of the J-integral, a one parameter of the non-linear fracture mechanics(NLFM), as a means to measure toughness of steel fiber reinforced concrete. This parameter can be conveniently evaluated from experimentally determined load-deflection curves from flexural tests when a maximum-load failure criterion is employed. And, for high strength concrete which was reinforced steel fiber, with two different fiber length in the form of notched beams, were tested under 3-point bending, and $J_{IC}$, as well as the linear elastic fracture mechanics(LEFM) parameters $K_{IC}$ and $G_{IC}$ were evaluated. The results suggest that $J_{IC}$ is a promising fracture criterion for all of these. while $K_{IC}$(or $G_{IC}$) almost certainly are not. Also it was found that a fiber addition of less than 0.5% did not improve the fracture toughness of the high strength concrete. However, at more than 1.0% in fiber contents, $J_{IC}$ showed significant increases. reflecting the changed character of the concrete; $K_{IC}$ and $G_{IC}$ did not.

• Korean Journal of Psychosomatic Medicine
• /
• v.7 no.1
• /
• pp.79-86
• /
• 1999

A comprison was made regarding perceived family support among patients with somatoform disorders, psychosomatic disorders and depressive disorders. The subjects included 49 patients with somatoform disorders, 43 patients with psychosomatic disorders, and 50 patients with depressive disorders. Perceived social support-family scale was used to measure the extent of family support. The patients with somatoform disorders were significantly lower in family support than the patients with psychosomatic disorders. However, no significant differences were found between patients with somatoform disorders and those with depressive disorders, as well as between patients with psychosomatic disorders and those with depressive disorders. Patients with older age had significantly higher scores on family support than those with younger age. Married patients were significantly higher in family support than unmarried ones. These results suggest that low family support may be associated with either the etiology or the sequelae of somatization. Thus, it is emphasized that the role of family support is essential in evaluation and treatment of somatization. In addition, longitudinal studies will be required to investigate the causative role of low family support in somatization.

• The Journal of Engineering Geology
• /
• v.27 no.4
• /
• pp.377-382
• /
• 2017

Field experiments were conducted to estimate streambed hydraulic conductivity at 15 sites in the Anseongcheon watershed, Korea. Seepage meters and piezometers were installed in the streambed at each site to measure the amount of stream water-groundwater exchange and the hydraulic gradient. The vertical hydraulic conductivity was then calculated using Darcy's formula. The measured stream water-groundwater exchange rates were $4.08{\times}10^{-6}$ to $1.49{\times}10^{-5}m/s$, and the vertical hydraulic gradients were 0.005 to 0.145. The data suggest the streambed hydraulic conductivity to be $7.80{\times}10^{-5}$ to $1.58{\times}10^{-3}m/s$. The results show significant differences in connectivity between stream and aquifer. Quantification of the hydraulic interconnection between stream and aquifer, and evaluation of the effects of groundwater development and utilization on the streamflow require hydrogeological investigations of the connection between stream and aquifer, including the hydraulic conductivity of the streambed. Various field testing and analysis methods for hydrogeological assessment also require further improvement.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.3
• /
• pp.461-467
• /
• 2003

This paper proposes the method of mobility implementation for location searching in the intelligence wireless ATM networks that expand and apply standard broadband signaling capabilities, and analyze the performance based on the numerical algorithm. The existing B-ISDN UNI protocol stack demands the location search mechanism to determine the location of mobile terminal in the wireless ATM networks because it use single protocol through the fixed PTP interface or PTM interface that don't support terminal mobility. The proposed method make possible the dynamic mobility at a part of wireless access by minimizing the signaling load without a falling-off in system performance by using the intelligence network technology according to the expansion of ATM and B-ISDN signaling integration based on the fixed networks. We implemented the performance analysis by MFC modeling based on numerical algorithm, and realized the efficiency of expenses by carrying out the comparative signaling performance evaluation to measure the relative gains of location search service in the intelligence wireless ATM system. The obtained results have the flexibility to operate in the public B-ISDN network environment without a change of existing B-ISDN/ATM NNI signaling reference to support the wireless ATM access system, and can easily expand to correspond to terminal mobility and various multimedia services in the next broadband PCS.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.12
• /
• pp.147-151
• /
• 2016

Automatic exposure control (AEC) is frequently used in many hospitals for Standing Whole Spine examination which is able to control radiation dose with respect to the body type such as body mass index (BMI) and we can measure dose area product (DAP) based on respective patient information. However, few studies have been conducted organ absorbed dose evaluation based on location of patient organ. The purpose of this study was to evaluate the relationships between BMI and organ absorbed dose along with location of patient organ. For that purpose, we calculated absorbed dose with selected 5 patient organ (thyroid, breast, heart, kidney, and pancreas) using a PCXMC simulation tool with measured DAP. According to the results, measured DAP increases with BMI and organ absorbed dose decreases with BMI in anterior organs such as thyroid, breast, and heart. On the other hand, there is no correlation between organ absorbed dose and BMI in posterior organs such as kidney and pancreas. In conclusion, our results demonstrated that the radiation effects are different with respect to BMI and location of patient organ in Standing Whole Spine examination.

• Journal of Radiation Protection and Research
• /
• v.24 no.2
• /
• pp.109-120
• /
• 1999

Residual radiation and radioactivity level in TRIGA Mark-II, III research reactors and facilities at the KAERI Seoul site, which are to be decommissioned, have been measured, analyzed and evaluated to know the current status of radiation and radioactivity level and to establish and to provide the technical requirements for the safe decommissioning of the facilities which shall be applied in minimizing the radiation exposure for workers and in preventing the release of the radioactive materials to the environment. Radiation dose rate and surface radioactivity contamination level on the experimental equipments, floors, walls of the facilities, and the surface of the activated materials within the reactor pool structure were measured and evaluated. Radioactivity and radionuclides in the pool and cooling water were also analyzed. In case of the activated reactor pool structures which are very difficult to measure the radiation and radioactivity level, a computer code Fispin was additionally used for estimation of the residual radioactivity and radionuclides. The radiation and radioactivity data obtained in this study were effectively used as basic data for decontamination and dismantling plan for safe decommissioning of TRIGA Mark-II, III facilities.

• Journal of Technology Innovation
• /
• v.22 no.3
• /
• pp.225-260
• /
• 2014

In this paper, we present a literature review of the mechanisms and methodology for technology spillover, in order to provide a theoretical and practical foundation for estimating the technology spillover effect of public funded R&D programs. Our research consists of four parts. First, we investigate what technology spillover is and how it works. Second, we review the methodology used to empirically measure technology spillover, with a view to understanding the advantages and disadvantages of each method. Third, we identify the gap between the spillover phenomenon and its estimated results, caused by the limitations of the methodology, and discuss the challenges in measuring technology spillover. Finally, we present several considerations to improve the measurement of technology spillover in the context of public funded R&D programs. Our paper provides policy makers and researchers with basic knowledge about technology spillover and helps them suitably evaluate the results obtained from the literature review. In addition, it contributes towards improving the existing methodology by recognizing the gap between the spillover phenomenon and the methodology.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.5
• /
• pp.2206-2211
• /
• 2012

To identify the effect of the aroma foot spa on the stress, 12 university students with stress were divided into control group (6 subjects) and aroma foot spa group (6 subjects). Control group was not subjected to any kind of intervention while aroma foot spa group was subjected to 10 minutes of foot bath using 5% Juniper, lavender and lemon essential oil and 10 minutes of foot massage using massage cream during four weeks, two times per week. As for the evaluation method, brain wave was studied to measure the amount of change in stress. After measuring the change in the brain wave before and after the experiment, it was proven that the aroma foot spa group s Alpha wave (Z=-2.364, p<.05) and SMR wave (Z=-1.981, p<.05) were higher than those of the control group. Moreover, when the pre and post experiment results of the aroma foot spa group were measured, it was proven that the Theta wave (Z=-2.366, p<.05) decreased while Alpha wave (Z=-2.371, p<.05) increased. In other words, aroma foot spa that included foot bath using essential oil and foot massage increased Alpha wave which in turn influenced the brain wave due to increased blood circulation resulting from muscle relaxation. Moreover, SMR wave increase was closely related to the change in Alpha wave, which demonstrates that SMR wave increased due to stress alleviation. Accordingly, it may be possible to assume that aroma foot spa is effective in relieving stress.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.10
• /
• pp.1-6
• /
• 2019

As mobile technologies such as Internet of Things (IoT)-based smart homes and financial technologies (FinTech) are developed, authentication by smart devices is used everywhere. As a result, presence-based biometric authentication using smart devices has become a new mainstream in knowledge-based authentication methods like the existing passwords. The electrocardiogram (ECG) is less prone to forgery, and high-level personal identification is its unique feature from among various biometric authentication methods, such as the pulse, fingerprints, the face, and the iris. Biometric authentication using an ECG is receiving a great deal of attention due to its uses in healthcare and FinTech. In this study, we implemented an ECG authentication system that allows users to easily measure and authenticate their ECG waveforms using a miniaturized wearable device, rather than a large and expensive measurement device. The implemented ECG authentication system identifies ECG features through P-Q-R-S-T feature point identification, and was user-certified under the proposed authentication protocols. Finally, assessment of measurements in a majority of adult males showed a relatively low false acceptance rate of 1.73%, and a low false rejection rate of 4.14%, in a stable normal state. In a high-activity state, the false acceptance rate was 13.72%, and the false rejection rate was 21.68%. In a high-heart rate state, the false acceptance rate was 10.48%, and the false rejection rate was 11.21%.