• Journal of Korean Society of Steel Construction
• /
• v.22 no.1
• /
• pp.21-31
• /
• 2010

In this study, a technique that uses wireless impedance sensor nodes is proposed to monitor tensile force of structural cable. To achieve this goal, the following approaches were implemented. First, a wireless impedance sensor node was designed for automated and cost-efficient prestress-loss monitoring. Second, an impedance-based algorithm was embedded in the wireless impedance sensor node for autonomous structural health monitoring of structural cables. Third, a tensile force monitoring technique that uses an interface plate for structural cables was proposed to overcome the limitations of the wireless impedance sensor node such as its narrow-band measurable frequency ranges. Finally, the applicability of the wireless impedance sensor node and the technique that uses the interface washer were evaluated in a lab-scaled prestressed concrete (PSC) girder model with internal and external tendons for which several prestress-loss scenarios were experimentally monitored with the wireless impedance sensor nodes.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.21 no.1
• /
• pp.83-90
• /
• 2008

A vibration-based monitoring system is newly proposed to predict the loss of prestress forces in prestressed concrete (PSC) girder bridges. Firstly, a global damage alarming algorithm is newly proposed to monitor the occurrence of prestress-loss by using the change in frequency responses. Secondly, a prestress-loss prediction algorithm is selected to estimate the extent of prestress-loss by using the change in natural frequencies. Finally, the feasibility of the proposed system is experimentally evaluated on a scaled PSC girder model for which acceleration responses were measured for several damage scenarios of prestress-loss.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.36D no.10
• /
• pp.1-8
• /
• 1999

In this paper, we have studies the transport mechanism and origin of SILC for the various thickness of wet oxide. Also, SILC characteristics of $N_2O$ annealed oxide was included in this study. We made the flash memory cell with $N_2O$ annealed oxide of 60Athick under $0.25{\mu}m$ design rule, and measured the characteristics of the cell. As a result, we have found that the origin of SILC is due to the trap formed inside of the oxide layer by electrical stress. And we reached the conclusion that the transport mechanism of SILC is ruled by the modified F-N tunneling if the electric field is lower than 8MV/cm or typical F-N tunneling if the electric field is higher than 8MV/cm. We could also confirm the fact that $N_2O$ annealed oxide of 60Athick have an improved resistance effect against SILC. In case that we apply $N_2O$ annealed oxide of 60Athick to the flash memory, we could confirm $10^6$ times endurance and more than 10 years drain disturb, and could get 8V programmable flash memory characteristics.

• Journal of the Korean Institute of Telematics and Electronics T
• /
• v.35T no.1
• /
• pp.29-32
• /
• 1998

The low level leakage currents in silicon oxides were investigated. The low level leakage currents were composed of a transient component and a do component. The transient component was caused by the tunnel charging and discharging of the stress generated traps nearby two interfaces. The do component was caused by trap assisted tunneling completely through the oxide. The low level leakage current was proportional to the number of traps generated in the oxides. The low level leakage current may be a trap charging and discharging current. The low level leakage current will affect data retention in EEPROM.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.1A
• /
• pp.135-146
• /
• 2008

In this paper, a hybrid damage monitoring scheme for prestressed concrete (PSC) girder bridges by using sequential acceleration and impedance signatures is newly proposed. Damage types of interest include prestress-loss in tendon and flexural stiffness-loss in a concrete girder. The hybrid scheme mainly consists of three sequential phases: damage alarming, damage classification, and damage estimation. In the first phase, the global occurrence of damage is alarmed by monitoring changes in acceleration features. In the second phase, the type of damage is classified into either prestress-loss or flexural stiffness-loss by recognizing patterns of impedance features. In the third phase, the location and the extent of damage are estimated by using two different ways: a mode shape-based damage detection to detect flexural stiffness-loss and a natural frequency-based prestress prediction to identify prestress-loss. The feasibility of the proposed scheme is evaluated on a laboratory-scaled PSC girder model for which hybrid vibration-impedance signatures were measured for several damage scenarios of prestress-loss and flexural stiffness-loss.

• Review of KIISC
• /
• v.17 no.1
• /
• pp.22-32
• /
• 2007

유비쿼터스 건강관리를 가능하게 하는 U-health의 중요성이 부각됨에 따라 다양한 U-health 서비스들이 개발, 제공 되고 있다. 하지만 대부분의 서비스들이 제한적이고 독립적으로 구성되어 있어서 다른 서비스와의 연동을 통한 폭넓은 서비스의 제공이 어렵다. 이러한 서비스 연동을 위해서는 U-health 데이터 및 단위 서비스를 체계적으로 관리하고, 맞춤형 U-health 서비스 개발에 필요한 단위 서비스 검색 방법이 필요하다. 이 논문에서는 온톨로지를 이용하여 U-health 데이터 및 서비스들을 체계적으로 명세하고 관리하기 위한 방법과, 온톨로지 정보를 이용하여 의미적으로 서비스를 검색할 수 있도록 하는 서비스 브로커링 방법을 제안한다. 그리고 이를 활용해 스트레스 관리 U-health 서비스를 구축한 사례를 설명한다.

• The Journal of the Korea Contents Association
• /
• v.19 no.6
• /
• pp.655-662
• /
• 2019

Based on phenomenological view a research utilizing qualitative methodology to understand about parenting difficulty and stress through an in-depth interview with grandmother in low-income grandparent-headed family was administrated. The results indicated that experience with parenting stress of grandmother in low-income grandparent-headed family lead to economic hardship, grandchildren who are a barrier of old-age, and desolate parenting. This article implicates that a basis to guide a direction and role of social welfare intervention to alleviate parenting stress of grandmother in grandparent-headed family and to improve a life quality emergent on the results could be provided. Several considerations on this finding shows as follows. First, with currently active support project re-monitored and re-checked, support program could be needed to enlarge. Second, support program development and social support to decrease parenting stress and depression of grandmother in grandparent-headed family could be necessary. With educational and cultural as well as mentoring program helpful for grandmother parenting designed, a support system to complement non-sufficient support network will be established together.

• Journal of the Health Care and Life Science
• /
• v.8 no.2
• /
• pp.165-172
• /
• 2020

This study was conducted to identify the subjective happiness and self-esteem of nursing students and how these variables affect clinical practice stress. Participants consisted of 199 nursing students who were in the third and fourth years who had experienced clinical practice at two nursing universities located in Gyeongnam, and agreed to the survey. Data were collected using questionnaires from June 15 to August 29, 2020. Collected data were analyzed using the SPSS 22.0 statistics program with descriptive statistics, an independent t-test, ANOVA, Scheffe's test, and multiple regression. The mean score for subjective happiness was 4.87 (out of 7), the mean for self-esteem was 3.84 (out of 5), and clinical practice stress was 2.77 (out of 5). The significant predictors of the clinical practice stress were gender, major satisfaction and self-esteem, and the explanatory power of variance was 14.1%. Therefore, we need differentiated clinical practice stress reduction programs according to gender and various strategies that can enhance major satisfaction in order to reduce the clinical practice stress of nursing students.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.1
• /
• pp.107-117
• /
• 2011

In this study, the effect of temperature-induced uncertainty to damage monitoring using acceleration-impedance response features is analyzed for presterssed concrete(PSC) girder bridges. Firstly, a damage monitoring algorithm using global and local vibration features is designed. As global and local features, acceleration and electro-mechanical impedance features are selected respectively. Secondly, the temperature effect on the acceleration and impedance features for a lab-scaled PSC girder is experimentally analyzed. From the experimental results, compensation models for temperature-acceleration features and temperature-impedance features are estimated. Finally, the feasibility of the acceleration-impedance-based damage monitoring technique using the compensation model is evaluated in the PSC girder for which a set of prestress-loss and flexural stiffness loss cases were dynamically tested.

• Journal of Korean Academy of Nursing
• /
• v.43 no.5
• /
• pp.605-612
• /
• 2013

Purpose: The purpose of this study was to investigate the casual relationship between nurses' mentoring and turnover intention and to verify the goodness of fit between a hypothetical model and actual data in order to suggest an adequate model. Methods: The survey was conducted with 434 nurses working in general hospitals in Seoul. Data were collected during February 2013, and analyzed with SPSS Windows 18.0 and AMOS 7.0. Results: Mentoring was found to have a direct effect on decrease in role stress. Role stress had a direct effect on increase in burnout and mentoring, with role stress as a mediator, there was an indirect effect on burnout. Burnout had a direct effect on increase in turnover intention, and role stress, with burnout as a mediator, and mentoring, through role stress and burnout, an indirect effect was found on increase in turnover intention. Conclusion: The results of this study indicate that nursing managers should put effort into reducing role stress and burnout, while seeking to establish a more efficient mentoring system so that for nurses, there will be a lowering of turnover intention.