• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.2
• /
• pp.16-22
• /
• 2021

In this paper, a solid capsule was prepared using a crystal growth type inorganic material capable of hydration reaction. The solid capsules were mixed at 3, 5, and 10% according to the composition ratio of 8:2, 7:3, 6:4 based on the cement mass, and the self-healing mortar was mixed, Durable healing properties were evaluated through the water permeability test. As a result of the water level permeability test, the effect of optimally improving the natural healing performance was shown by mixing the solid capsules prepared in a composition ratio of 7:3 of the solid capsules. In the case of a crack width of 0.3mm or less, it is estimated that more than 90% of the self-healing performance can be secured. As a result, it was judged that the self-healing performance of the solid capsule had an effect on the durable healing properties through the water permeability test, It is judged that there is a tendency to improve self-healing performance according to the mixing of solid capsules.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.3 no.2
• /
• pp.46-49
• /
• 2010

This paper has proposedfor wireless Ad-hoc networks with robust route maintenance schemes. The device feature Bluetooth and/or IEEE 802.11 network interfaces and communicate in a decentralized manner. The nodes have the responsibility of self-organizing so that the network is robust to the variations in network topology due to node mobility as well as the fluctuations of the signal quality in the wireless environment.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.1460-1460
• /
• 2015

Power equipment, since different life according to use environment, there is a need for systematic maintenance management Efforts to reduce the economic losses due to accidents by making self evaluation table will be necessary.

• Structural Monitoring and Maintenance
• /
• v.5 no.2
• /
• pp.189-204
• /
• 2018

This paper examines the seismic responses of a reinforced concrete (RC) frame core-tube building with pre-pressed spring self-centering energy dissipation (PS-SCED) braces. The PS-SCED brace system consists of friction devices for energy dissipation, pre-pressed combination disc springs for self-centering and tube members as guiding elements. A constitutive model of self-centering flag-shaped hysteresis for PS-SCED brace is developed to better simulate the seismic responses of the RC frame core-tube building with PS-SCED braces, which is also verified by the tests of two braces under low cyclic reversed loading. Results indicate that the self-centering and energy dissipation capabilities are well predicted by the proposed constitutive model of the PS-SCED brace. The structure with PS-SCED braces presents similar peak story drift ratio, smaller peak acceleration, smaller base shear force and much smaller residual deformations as compared to the RC frame core-tube building with bucking-restrained braces (BRBs).

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.11a
• /
• pp.111-112
• /
• 2014

This research focuses on the study that micro-crack of concrete is repaired to use self-healing technology. Self-healing concrete is widely studied in domestic and international construction field recently. Micro-crack(less than 0.3mm)of concrete is repaired using a crack repair stick which containing self-healing agents. Therefore, the crack on construction structure will be easily repaired by using a crack repair stick. Also experiment was proceeded because of evaluating the long term durability.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.1
• /
• pp.113-118
• /
• 2012

This thesis suggests how to design and implement an Android smart phone application which can perform self check or safety inspection of lifts effectively. The safety checks of lifts go in the way that inspectors check the lifts' conditions generally and record manually following a form at the moment. This thesis analyses lift maintenance industry and introduces how to design a system to proceed effective self check using a smart phone with Android OS. By using a smart phone to check lifts, we can have advantages to improve the quality of self check and maintain careers establishing information database about safety items.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.25 no.6
• /
• pp.553-560
• /
• 2022

This study investigates improvement of torsional strength of special wrench for K-series self-propelled howitzer power-pack maintenance. In order to maintain the power-pack, special wrench is one of the essential tools for assembling/disassemblimg the engine and transmission. However, failures(plastic deformation, fracture phenomenon and etc.) have been frequently reported even though special wrench was used within recommended standard torque range. Therefore, in this study, finite element analysis using ABAQUS was performed and modification of design parameters have been proposed. Prototypes based on the proposed parameters were manufactured and torsional experiment(torque about 130 % of recommend maximum torque) validated the newly proposed design parameters. Special wrench based on this study is applied to mass production and currently used for the maintenance.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.5
• /
• pp.127-132
• /
• 2018

The amount of generated Circulating Fluidized Bed Combustion ash (CFBC ash) is annually increasing, but most CFBC ash has been landfilled and discarded due to the limited utilization. The major chemical compositions of CFBC ash are $SiO_2$, CaO and $CaSO_4$, which could form hydration products by reacting with water as self-cementing property such as cement. The purpose of the this study is to derive the optimal mix proportions to improve polymer-modified mortar with the use of CFBC ash which has the self-cementing property. In order to develop polymer-modified mortar, three mix proportions were determined, and fundamental properties for the mixtures were obtained. As a result, the optimal mixture containing 10 percent of silica fume, 1.0 percent of polymer and 3.5 percent of expansive additives were proposed in this study.

• 한국노년학
• /
• v.28 no.4
• /
• pp.1213-1225
• /
• 2008

The purpose of this study was to determine psychosocial variables of exercise behaviors for old adults. A major research problem identified through theory of planned behavior and it's empirical data: Do cognitive-social variables(health risk perception, self-efficacy, group conformity, exercise attitude) significantly mediate exercise behaviors(intention, action, maintenance)? A total of 453 older adults above 65 years(171 males and 282 females) who were enrolled in various classes were randomly selected at adults centers in Seoul. Participants completed a battery of questionnaires including the psycho-social variables(health risk perception, self-efficacy, group conformity, exercise attitude) and exercise behaviors(intention, action, maintenance). The results of statistical procedures(e.g., hierarchical multiple regression) indicated self-efficacy and exercise attitude significantly predicted exercise intentions of older adults. Exercise intention was a significant predictor of action, and action was a significant predictor of exercise maintenance. In discussion, various psycho-social mechanisms were provided to interpret the results of this study, and future directions were suggested.

• Journal of Preventive Medicine and Public Health
• /
• v.42 no.2
• /
• pp.109-116
• /
• 2009

Objectives : This study was performed to evaluate the relationships between psychosocial characteristics and changes in the stage of breast cancer screening behavior. Methods : The 474 study subjects were randomly sampled from 21,459 women(age range, 40-70 years) who were eligible for the Korean National Cancer Screening Program in 2006 in Jinju, Gyeongsangnam-do. The information, including behaviors and sociodemographic characteristics, attitudes, subjective norms and self-efficacy, was collected by trained interviewers via home visits. The breast cancer screening stages were grouped as precontemplation, contemplation, action, maintenance and relapse, according to Rakowski. Results : Of the 474 women, 18.8% were in the precontemplation stage, 23.3% were in the contemplation stage, 13.1% were in the action stage, 36.6% were in the maintenance stage, and 8.2% were in the relapse stage. The distribution of stages was associated with attitude, subjective norms and self-efficacy(p for trend<0.01). To investigate the overall relationship between the variables, we conducted a linear structural equation model analysis based on the theory of planned behavior. The subjective norms and self-efficacy influenced the stage of the women's screening behavior. Conclusions : We should target on self-efficacy about the screening behavior of women by performing timely, thoughtful interventions. The support from family members, friends and other people is crucial for women to undergo breast cancer screening and to improve the breast cancer screening rate.