• Magazine of korean Tunnelling and Underground Space Association
• /
• v.14 no.2
• /
• pp.31-37
• /
• 2012

In the circumstances being continuous the unusual weather in the world, the city of Seoul has been devastating flood damage in July 2011, because of the heavy rainfalls. Along with expensive repairs to property, thousands of flood victims occurred; it is difficult to estimate the direct and indirect economic damages in city. Recently, as a part of the flood protecting measures, there are being discussed about the deep underground flood drainage tunnel, underground regulating reservoirs, permeable pavement, infiltration facility, river improvements, diversion channel, sewer pipe and ditch improvement and so on. Therefore, it is useful to make the plan of flood protecting measures more and more cost-effective and rational methods by considering the similar flood measures and constructions in the mega cities like Seoul.

• Structural Engineering and Mechanics
• /
• v.14 no.5
• /
• pp.543-563
• /
• 2002

The use of the epoxy pressure injection technique to rehabilitate reinforced concrete beam-column joints damaged by strong earthquakes is investigated experimentally and analytically. Two one-half-scale exterior beam-column joint specimens were exposed to reverse cyclic loading similar to that generated from strong earthquake ground motion, resulting in damage. Both specimens were typical of new structures and incorporated full seismic details in current building codes. Thus the first specimen was designed according to Eurocode 2 and Eurocode 8 and the second specimen was designed according to ACI-318 (1995) and ACI-ASCE Committee 352 (1985). The specimens were then repaired with an epoxy pressure injection technique. The repaired specimens were subjected to the same displacement history as that imposed on the original specimens. The results indicate that the epoxy pressure injection technique was effective in restoring the strength, stiffness and energy dissipation capacity of specimens representing a modem design.

• Structural Engineering and Mechanics
• /
• v.18 no.3
• /
• pp.277-286
• /
• 2004

Defective metallic components and structures are being repaired with bonded composite patches to improve overall mechanical and fatigue properties. In this study, fatigue crack growth tests were conducted on pre-cracked 7075/T6 Aluminum substrates with and without bonded Boron/epoxy patches. A considerable increase in the fatigue life and a decrease in the stress intensity factor (SIF) were observed as the number of patch plies increased. The experimental results demonstrate that the patch configurations and patch thickness can enhance fatigue life by order of magnitude. Quantitative comparisons between analytical and experimental data were made, and the analytical model based on a modified Rose's analytical solution appears to best estimate the fatigue life.

• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.1263-1266
• /
• 1997

In a fault-tolerant modern manufacturing systms characterized by the configuration, in which automated redundant machines prone to unexpected failures are interconnected with other complex subsystems such as AGV's, robots, computer control systems to produce complete parts, faulures together with repairs and reconfigurations should be considered as the three basic events to be modeled for computing the performance of manufacturing systems. In this papre, transient analysis is applied to modular cell manufacturing systems form a performability viewpoint whose modeling adantage is that various performanc e measures can be evaluated compositely in the context of application. The hypothertical modular cells are modeled firstly with hybrid decomposition method and availability measures as special cases of performability are computed and comments on performabililty modeling analysis are mentioned.

• Journal of Industrial Technology
• /
• v.21 no.B
• /
• pp.163-174
• /
• 2001

A dynamic reliability model for analyzing the stability of armor units on rubble-mound breakwater is mathematically developed by using Hudson's formula and definition of single-failure mode. The probability density functions of resistance and loading functions are defined properly, the related parameters to those probability density functions are also estimated straightforwardly by the first-order analysis. It is found that probabilities of failure for the stability of armor units on rubble-mound breakwater are continuously increased as the service periods are elapsed, because of the occurrence of repeated loading of random magnitude by which the resistance may be deteriorated. In particular, the factor of safety is incorporated into the dynamic reliability model in order to evaluate the probability of failure as a function of factor of safety. It may thus be possible to take some informations for optimal design as well as managements and repairs of armor units on rubble-mound breakwater from the dynamic reliability analyses.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.11a
• /
• pp.95-96
• /
• 2015

This paper aims to identify patterns in users' requests for facility management (FM) services in higher education facilities. We analyzed data collected from 309 service request forms, made available via a department office and an enterprise resource planning system, at a private university in Seoul between May 2009 and February 2015. We found that the number of user requests were the highest in September and October. Requests for electronic and communication (E/C) services outnumbered those for architectural services and mechanical and plumbing (M/P) services. Repair requests for doors and windows were the most common under architectural services; repairs for air-conditioners and radiators were the most commonly under M/P services; and installation of electrical outlets, telephone wires, and internet services were the most sought-after E/C services. Maintenance requests were received every three months, while repair requests were received every six or seven months.

• Journal of architectural history
• /
• v.29 no.3
• /
• pp.25-36
• /
• 2020

The purpose of this study was to analyze the correlation between conservation activities and the development of tourism in the modern period in the Korean peninsula. The main building of Jangansa Temple, located in Mt. Geumgang, was repaired in the 1930s. During the repairs, the Japanese General-Government actively engaged in the development of Mt. Geumgang and raised funds for the operation of the Korean Peninsula through tourism revenue. The repair work was carried out under the influence of the Mt. Geumgang development project. And its influence is revealed by reviewing official documents recording repair work. This study tried to clarify the relationship between development and repair work through official documents.

• Journal of Korean Society for Quality Management
• /
• v.18 no.2
• /
• pp.33-42
• /
• 1990

This paper proposes the maintenance model of multi-component system when the failure characteristics and types of components are considered. In this model, it is assumed that a system is composed of a critical component, a major component and a minor component. Also, failure types is classified into major failure and minor failure. If major failure occurs to critical component before system age replacement time, the system is renewed. If major failure does not occur until its age replacement time, preventive maintenance is performed at age replacement time T. Minimal repairs are carried out after each minor failure. Major component is minimal-repaired if any failure is discovered during operation. Minor component should be replaced as soon as any failure is found. This paper determines the optimal replacement time of the system which minimizes total maintenance cost. Numerical example illustrates these results.

• Clinics in Shoulder and Elbow
• /
• v.18 no.4
• /
• pp.254-260
• /
• 2015

With the advancement of shoulder arthroscopy, use of biodegradable suture anchors in the surgical repair of rotator cuff tears has increased. Because of the radiolucency of these anchors, radiography is not appropriate for early detection of anchor failure. Ultrasonography is an advantageous modality in visualizing biodegradable, radiolucent anchors on a real-time basis without risk of radiation exposure. We report on two cases of displacement of a biodegradable suture anchor diagnosed on ultrasonography during the postoperative follow- up, which has not been previously reported. Because this displacement could be missed in the postoperative follow up ultrasonography, we describe the ultrasonographic features of the displaced biodegradable anchors. Surgeons and radiologists should pay special attention to the possibility of displacement of the suture anchor in patients who underwent rotator cuff repairs using suture anchors.

• Proceedings of the KACD Conference
• /
• 2002.11a
• /
• pp.719-719
• /
• 2002

Aesthetic and cosmetic dentistry is becoming a major source of the dentists practice and source of income. Patients are demanding dentists to improve and enhance their appearance and function by means of aesthetic contouring and orthodontics and are willing to pay for such services. This creates a challenge for the dental profession to gain more knowledge and skill in this important area of their practice. Ceramic and composite veneers provide a comprehensive solution to the dentition that are severely hypoplastic or deeply stained by the ingestion of tetracycline during tooth development. A large number of dental materials and new techniques are now available that will render extremely satisfactory and beautiful solutions to these previously unsightly dentitions. This presentation will present the most commonly used dental materials and techniques of fabrication of composite and porcelain veneers. Using clinical cases, the step by step cavity preparations.Impression taking, laboratory fabrication, clinical try-in and cementation materials and techniques and repairs of broken veneers as well as long term follow up will be presentedesented