• Journal of the Korea institute for structural maintenance and inspection
• /
• v.2 no.4
• /
• pp.148-158
• /
• 1998

Determining the thickness if concrete lining and detecting of the cavity where is located behind tunnel lining plays an important role in the safety diagnosis of tunnel structure and the quality control. In this study, we made use of GPR and seismic method in order to find the cavity or flaw. Although GPR is very useful method in the concrete lining without rebar, it is difficult to detect the cavity in the reinforced concrete lining. We applied mini-seismic method to the reinforced concrete lining. The obtained seismic data was processed by means of seismic section in time domain and image section of power spectrum in frequency domain using Impact-Echo method as well. The proposed method can accurately show the location and depth of the cavity in the reinforced concrete lining.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.723-724
• /
• 2007

Live line work is well known for mending and maintenance of electrical power equipment. Nowadays needs of electric power supply quality require live line work In Korea, live line work is needed since 765kV transmission operation and restructure of electric power industry has changed. In other words, in case of suspension of power supply on the transmission is getting hard to keep up with efficiency of transmission operation, customer's confidence and generation-limited cost. Therefore live line work is very meaningful. As the condition of 765kV Transmission both bare hand and Helicopter live line technique must be used in moderation because of economic, geographical, environmental circumstances around steel tower.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.548-552
• /
• 2002

The necessity of a short period of software development with lower cost came out. The reason of making the component based development is that it can improve the software development , productivity maintenance , and software quality innovatively. Following these advantages of component based application development methods, we found the COM based components effective to Window platform in the satellite surveying. In this paper, we can obtain many precious engineering experiences. Software system development and maintenance will take much shorter time with higher reusability if satellite surveying system is constructed with component extraction proposed by us.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.3 no.2
• /
• pp.155-160
• /
• 1999

Recently, the study on mix design of lightweight concrete using the polystyrene foam balls is put into practice from the viewpoint to grade up the quality of concrete and recyclable usage of industrial by products. Polystyrene aggregate concrete, PAC, can be used as structural concrete in low strength application. For instance, PAC could be used in the middle part of sandwich panel where stresses are generally low and in the case of grid-type reinforcement where it does not need high bond strength but little compressive strength to resist the pressure of transverse reinforcement. From this point of view, the authors discussed the influence of fluidity and compressive strength of concrete by the difference of the volume percentage of polystyrene foam balls and water cement ratio.

• International Journal of High-Rise Buildings
• /
• v.12 no.4
• /
• pp.321-333
• /
• 2023

Structural health monitoring is a technology or research field that extends the service life of structures and contributes to the prevention of disaster accidents by continuously evaluating the safety, stability, and serviceability of structures as well as allowing timely and proper maintenance. However, the contact-type sensors used for it require considerable time, cost, and labor for installation and maintenance. As an alternative, computer vision has attracted attention recently. Computer vision has the potential to make quality, deformation, and damage monitoring for structures contactless and automated. In this study, research cases in which computer vision was utilized for structural health monitoring are introduced, and its effects and limitations are summarized. Therefore, the applicability and future research directions of computer vision-based structural health monitoring are discussed.

• Journal of Korean Society of Water and Wastewater
• /
• v.34 no.4
• /
• pp.239-250
• /
• 2020

In this study, effects of five raw water quality parameters (turbidity, odor compounds caused by algae, filter clogging caused by algae, pH increase caused by algae, and organic matter) on improvements and operations costs of typical water treatment plant (WTP) were estimated. The raw water quality parameters were assumed the worst possible conditions based on the past data and costs were subsequently estimated. Results showed that new water treatment facilities were needed, such as a selective intake system, an advanced water treatment processes, a dual media filter, a carbonation facility, and a re-chlorination facility depending on water quality. Furthermore, changes needed to be made in WTP operations, such as adding powered activated carbon, increasing the injection of chlorine, adding coagulation aid, increasing the discharge of backwashed water, and increasing the operation time of dewatering facilities. Such findings showed that to reliably produce high-quality tap water and reduce water treatment costs, continuous improvements to the quality of water sources are needed.

• Korean Journal of Construction Engineering and Management
• /
• v.5 no.3 s.19
• /
• pp.137-145
• /
• 2004

Owing to the growth of Information Technology, some of big general contractors have been interested in the development of Quality Management Information Systems to integrate the information of quality in planning, design, procurement, construction, and maintenance phases, and tried to maximize the usefulness of it. But the trend has confined only to some big general contractors. The purpose of this paper is to put together and analyze the character of Quality Management Information Systems of big general construction companies and classfy them into a result-focused system and a process-focused system in order to provide primary information for both of development and adoption of the systems.

• Journal of Korean Society for Quality Management
• /
• v.47 no.3
• /
• pp.453-465
• /
• 2019

Purpose: A main purpose is to increase the operational rate and reduce operating maintenance costs by Improving the durability of Blower of Military Armored Vehicle and Self-propelled Artillery. As a result, it is expected to improve the service quality of customers. Methods: After analyzing the cause of the stop of the blower, the improvement plans were established and the effectiveness of each improvement plans were verified by testing. Results: Mechanical, electrical and environmental factors affecting brush wear were reviewed, but it was difficult to specify the cause, which necessitated a review of the application of the BLDC motor. Conclusion: After applying the BLDC motor to the blower, tests proved that the existing blower can be replaced. It is expected that this study will help improve the durability life of similar equipment that is applied with Brushed DC motors as well as blowers.

• Journal of Korean society of Dental Hygiene
• /
• v.19 no.4
• /
• pp.577-589
• /
• 2019

Objectives: The purpose of this study was to investigate the effects of general and oral health on quality of life in the elderly living alone and with family. Methods: We analyzed data from the $6^{th}$ Korea National Health and Nutrition Examination Survey. Distribution of the elderly living alone and with family based on the general characteristics and general and oral health was analyzed using complex-sample chi-square tests. Multiple logistic regression was used to analyze the factors affecting quality of life by calculating the 95% confidence intervals. Results: In the elderly living alone, the quality of life significantly correlated with restriction of activity, perceived general and oral health status, perceived stress, and speech difficulties. Further, in the elderly living with family, lower quality of life significantly correlated with restriction of activity, perceived health status, walking days per week, life time smoking history, Community Periodontal Index, and chewing and speech difficulties. Conclusions: The elderly are concerned with self-maintenance of general and oral health. Therefore, systematic policies related to health services need to be developed and operated at the national level. It is especially necessary to take social interest in the elderly living alone and a more continuous and professional approach in their health care.

• Journal of Conservation Science
• /
• v.35 no.1
• /
• pp.51-60
• /
• 2019

This paper provides quantitative data that describes the evolution of the air quality in the Whale and Sea Museum, located in the Iwate prefecture, collected after the 2011 Great East Japan Earthquake and tsunami. The museum was damaged significantly by the disaster, and restoration works continued for over six years. The air quality in the temporary storage facility and museum was monitored during the rehabilitation process. Evaluation of air quality is carried out by gas chromatography- mass spectrometry, ion chromatography and high-performance liquid chromatography. The results showed that the characteristics of the chemical components differed depending on the measurement locations inside the building. The museum atmosphere tended to be alkaline as the airtightness increased because of the maintenance works at the entrance. It was also determined that it was necessary to study the intake/exhaust routes and to clean them according to the contamination degree. In Japan, there are recommended museum air quality standards for acetic acid, formic acid, alkali, and aldehydes. The results indicated that these standards should not be used as a reference for damaged museums. Furthermore, at the temporary storage facilities for to store the collections during the rehabilitation of the museum, solvents such as ethyl benzene, toluene, and xylene are initially abundant, although they can be reduced by ventilation, while other components such as 2E1H was confirmed in this case are likely to remain.