• The Journal of Sustainable Design and Educational Environment Research
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• v.9 no.2
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• pp.1-8
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• 2010

This study is to present an engineering solution for the repair frequency and repair rates of a building. The existing data for the repair frequency and repair rates are used to draw the probability distribution for the generalized repair frequency and repair rate in a building. The suggested methodology can be widely used for most buildings to estimate the legal repair frequency and repair rates. Also, the methodology can be applied to resolve the risks on the maintenance costs in LC (Life Cycle) plans or LCC (Life Cycle Cost) analysis. As the future studies, there are the multiple regression analysis including the parameters on incurred costs and the decision methods on efficient repair and replacement.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.249-256
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• 1999

This study is intended to propose a systematic procedure for the development of the reliability-based seismic safety and cost-effective Performance criteria for design and upgrading of long span PC bridges. In the paper, a set of cost function models for life cycle cost analysis of bridges is proposed. The total life cycle cost functions consist of initial cost and direct/indirect damage costs considering repair/replacement costs, human losses and property damage costs, road user costs, and indirect regional economic losses. The damage costs are successfully expressed in terms of Park-Ang median global damage indices and damage probabilities. The proposed approach is successfully applied to model bridges in both regions of a moderate seismicity area like Seoul, Korea and a high one like Tokyo, Japan. It may be expected that the proposed approach can be effectively utilized for the development of cost-effective performance criteria for design and upgrading of various types of bridges as well as long span PC bridges.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.386-397
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• 2007

One major development in bridge life cycle cost analysis (LCCA) in recent years is to develop deterioration model for bridge components so that the times of repair/replacement throughout a component's life span can be properly determined. Taiwan also developed her own bridge LCCA model in 2003, integrating with the bridge inspection database in the local bridge management system (T-BMS). Under the framework of the local LCCA model, this study employs the reliability method in developing a deterioration model of bridge components. A component deteriorates through time in its reliability, which represents the probability of a component's condition index exceeds a user specified threshold. Model assumptions and rationale are described in the paper. The steps for applying the developed model are explained in detail. Results and findings are reported.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.931-937
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• 2012

In this study, we assessed environmental impacts of compound humidifiers using environmental life cycle assessment and presented the ways to improvements in energy consumption of them. We found eco-design parameters and $CO_2$-eq emissions in each stage of raw material acquisition, manufacturing, transportation, use and disuse in life cycle of the compound humidifiers. The highest $CO_2$ emission is found to be in the stage of use among all stages of life cycle, which is mainly due to power consumption in thermal heating of heating coil for sterilization during humidification. The power consumption and $CO_2$ emission in the stage of use can be reduced to 1/4 and 1/3 at the highest estimate through improvement of sterilization method, respectively. We suggested the replacement of conventional thermal heating coil by ultra violet light-emitting diodes (UV-LED) for sterilization and then presented the experimental results on the sterilization effects of UV-LEDs.

• Journal of Korean Physical Therapy Science
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• v.1 no.1
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• pp.145-163
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• 1994

This study was done to determine differences in effect of postoperative pain control in patients receiving auricular electroacustimulation vs transcutaneous electrical nerve stimualtion following total knee replacement surgery. Thirty-one cases referred to physical therapy department after treated by total knee replacement surgery by orthopedic surgery department at the Pohang St. Mary's Hospital from January 1993 through June 1994. Of 31 total knee replacement cases, 13 cases were auricular electroacustimulation group, 11 cases were transcutaneous electrical nerve stimulation group, and 7 cases were control group. The results of the study summerized are as follows: Thirty-one total knee replacement cases(male in 12 cases, female in 19 cases), ranging in age from 34 to 61 years(mean${\pm}$SD=49.90 7.56) with diagnoses of degenerative arthritis(20 cases), rheumatoid arthritis(9 cases), and other(2 cases). In auricular electroacustimulation group, there was a significant change of pain intensity, unpleasantness, and active range of motion after treatment(p<0.01). In transcutaneous electrical nerve stimulation group, there was a significant change of pain intensity, unpleasantness, and active range of motion after treatment(p<0.01). In control group, did not show significant pre-posttreatment differences in pain intensity, unpleasantness, active range of motion(p>0.05). The mean change in pain intensity and unpleasantness, active range of motion from pretreatment baseline for the 3 groups. Auricular electroacustimulation group showed the large magnitude of increase in pain intensity and unpleasantness, active range of motion when compared to its own pretreatment cycle. Transcutaneous electrical nerve stimulation group showed small magnitude of increase in pain intensity and unpleasantness, active range of motion when compared to its own pretreatment cycle. No significant changes were observed in control group. Highly significant differences in pain intensity, unpleasantness, and active rage of motion were found using an ANOVA measures between treatment groups and control group(p<0.01). The squares correlation coefficients of pain and function measures pretreatment-posttreatment differences for each group. In treatment group, there was significant correlation between pain scale and function(p<0.001). In control group, there was no correlation between the pain scale and function (p>0.05). The continuous study is needd for many interesting issues of auricular electroacustimulation in new future.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.1
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• pp.57-78
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• 2022

The disc cutter and cutterbit, which are the most important factors to increase the excavation efficiency of TBM, are key factors in the design and construction of the cutter head. The arrangement, spacing, number, size, and material of disc cutters suitable for the ground conditions determine the success or failure of TBM construction. The disc cutter, which is a representative consumable part in TBM construction, can cause enormous disruption to the construction cost as well as the construction cost unless accurate prediction of wear and replacement cycle is accompanied. Therefore, in this study, the method of calculating the replacement cycle of the disc cutter calculated at the time of design for the slurry shield TBM field, and the depth of wear and replacement location of the disc cutter that occurred during actual construction were compared by analyzing the field data. For a quantitative comparison, weathered soil/weathered rock, soft rock, and hard rock were classified according to the ground in the section showing constant excavation data, and the trajectory of circle was different depending on the location of the disc cutter, so it was compared and analyzed.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.145-150
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• 2007

This study is a LCC case analysis on the school one of the BTL projects which is constructed by private organizations and rented to government. According to the RFP to make out documents, it is performed the case analysis based on the results of LCC calculation about maintenance & conservation costs; repairing costs and replacement costs. It is analyzed LCC on maintenance & conservation costs for 20 years(rent period) and 65 years(life cycle). As a result of LCC analysis, about more than 50% of total LCC are architectural works and the rest of them are machinery works, electric works, and civil works in the order. And it is also suggested some problems and their solutions to perform LCC analysis on the current BTL projects of school.

• Journal of Sensor Science and Technology
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• v.30 no.2
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• pp.109-113
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• 2021

In this study, an automated culture media replacement system was developed to analyze changes in the contraction characteristics of cardiomyocytes according to the state of the culture media. For the long-term storage of culture media, a Peltier refrigerator with a temperature of 5 to 8℃ was provided and a pH of 7.4 was maintained. The cell culture media of the cardiomyocytes was continuously replaced using interlocking pumps at a flow rate of 0.83 μl/h. The cardiomyocytes in which the culture media was replaced automatically demonstrated lower heartbeats per minute compared to samples in which there was no replacement. However, these cardiomyocytes moved more uniformly and produced greater displacement in one heartbeat cycle. It was observed that the sarcomere length of the cardiomyocytes increased due to the automated culture media replacement system. These cardiomyocytes were found to demonstrate better maturation compared to the control group. The maturation of cardiomyocytes was verified through staining images. The proposed automated culture media replacement system generates a uniform heart rate and improvements in contraction force. Based on the study, patient-specific drug toxicity assessments can be conducted using differentiated cardiomyocytes in induced pluripotent stem cells.

• Journal of the Korean Data and Information Science Society
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• v.22 no.4
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• pp.775-784
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• 2011

In this paper, we consider the periodic preventive maintenance model for repairable system following the expiration of non-renewing free replacement-repair warranty (NFRRW). Under this preventive maintenance model, we derive the expressions for the expected cycle length, the expected total cost and the expected cost rate per unit time. Also, we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the optimal periodic preventive maintenance policy is given for Weibull distribution case.

• The Journal of Korean Physical Therapy
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• v.36 no.1
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• pp.27-32
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• 2024

Purpose: This study was conducted to verify the effect of applying a pressure biofeedback unit on walking ability and knee joint function while performing knee joint extensor strengthening exercises using resistance exercise equipment in total knee replacement (TKR) patients. Methods: This study was conducted on twelve patients receiving rehabilitation treatment after being admitted to a rehabilitation hospital post-TKR. Of these, six were allocated to a feedback group with a pressure biofeedback unit, and the other 6 were allocated to a control group without a pressure biofeedback unit. The subjects performed an exercise program for 45 minutes per session, five times a week, for two weeks. Walking ability and knee joint function were evaluated and analyzed before and after exercise. Results: The feedback group showed significantly better improvements in walking speed, gait cycle, step length on the non-operation side, time on the foot on the operation side, K-WOMAC stiffness, and K-WOMAC function than the control group (p<0.05). Conclusion: When strengthening the knee joint extensor muscles using resistance exercise equipment in TKR patients, the provision of a pressure biofeedback unit was found to improve walking ability and knee joint function by inducing concentric-eccentric contraction of the knee joint extensor muscles. Therefore, the study shows that exercise based on the provision of a pressure biofeedback unit should be considered when strengthening knee joint extensor muscles to improve the walking ability and knee joint function of TKR patients in clinical practice.