• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.11a
• /
• pp.1185-1192
• /
• 2001

This paper reviews available techniques for monitoring corrosion of steel in concrete. The need for early detection and diagnosis of corrosion related deterioration in reinforced structures is widely acknowledged. This is particularly important in reinforced concrete structures on account of the economic and social significance of the problem. The current generally used on-site procedure for corrosion monitoring of reinforced structures employs a method of half-cell surface potential measurements. While the technique has provided a useful means of delineating areas of high or low corrosion risk, there are difficulties in its use and interpretation when assessing rates of deterioration. Electrochemical techniques are by far the most suitable for corrosion monitoring purpose and meet most of the requirements. The aim of this paper is to describe the electric resistance sensor(ER sensor) and electrochemical techniques employed to monitor and estimate corrosion rates of reinforcement. Early detection and diagnosis of corrosion hazards allows preventive measures to be taken, hence the typically expensive repair of severely deteriorated structures can be avoided.

• Geomechanics and Engineering
• /
• v.15 no.1
• /
• pp.631-643
• /
• 2018

The estimation of the strength and other mechanical parameters characterizing the tensile behavior of granites can play an important role in civil engineering tasks such as design, construction, rehabilitation and repair of existing structures. The purpose of this paper is to apply data mining techniques, such as multiple regression (MR), artificial neural networks (ANN) and support vector machines (SVM) to estimate the mechanical properties of granites. In a first phase, the mechanical parameters defining the complete tensile behavior are estimated based on the tensile strength. In a second phase, the estimation of the mechanical properties is carried out from different combination of the physical properties (ultrasonic pulse velocity, porosity and density). It was observed that the estimation of the mechanical properties can be optimized by combining different physical properties. Besides, it was seen that artificial neural networks and support vector machines performed better than multiple regression model.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2003.11a
• /
• pp.81-86
• /
• 2003

Recently the introduction of VE & LCC techniques for large size electric power facilities be achieved in various kinds form, of and tends to evaluate to the beginning investment cost when think about cost of electric power facilities usually, but must consider all life cycle cost (maintenance cost, repair cost, improvement cost, operation cost, electric power cost etc.). This treatise applies design techniques that consider copper loss related by voltage drop at power supply of long distance in trunk design and all life cycle cost techniques

• Environmental Mutagens and Carcinogens
• /
• v.23 no.1
• /
• pp.16-22
• /
• 2003

Single nucleotide polymorphisms (SNPs) are alterations in DNA base that occur most frequently throughout the human genome. The SNPs of DNA repair genes, hMLH1, hMSH2 and ATM, among 100 Korean people were analyzed using Dynamic Allele specific Hybridization (DASH) techniques. Mutation at the position of exon 38 (GA) and exon 10 (CG) of ATM gene, mutation at the position of exon 8 (AG), and exon 1 (AG) of hMLH1 gene and exon 14 (AG) of hMSH2 gene were investigated. No mutation at the selected position of ATM gene and hMSH1 gene was found. However, while there was no mutation at the position of exon of hMSH2 gene, mutation was found at the promotion region (CT) with the frequency of 24% CC, 36% CT and 62% TT genotyes. This results might be used as baseline data for research on SNP of Korean population.

• International Journal of Precision Engineering and Manufacturing
• /
• v.1 no.2
• /
• pp.55-60
• /
• 2000

A comparison of Riveted and bonded repairs, bearing and net tension failures, and Al 6061-T6 plates is presented. The results are then compared with previous papers about bonded repairs on different patch materials and shapes. Aluminum alloys, including Al 6061-T6, have a face-centered-cubic crystal structure. Under normal circumstances, these types of crystal structures do not exhibit cleavage fractures even at very low temperatures. In aluminum-base structures, the cracked plate structures are frequently repaired using mechanical fasteners-either rivets of bolts- even though patch-bonding techniques are applied to repair and reinforce the structure. Static test results indicate that the riveted repairs are affected by the position of the rivers. When using the same size of patch, the bonded repair technique is stronger; the rate of elongation is also increased. Form FEM analysis, it is revealed the origin of patch debonding in patch-bonded structures is the edge of the patch along to the tensile strength.

• Clinics in Shoulder and Elbow
• /
• v.17 no.2
• /
• pp.91-100
• /
• 2014

Partial-thickness rotator cuff tear (PTRCT) is not single disease entity but one phase of disease spectrum. Symptoms of PTRCT vary from being asymptomatic to severe pain leading to deterioration in quality of life. Pathogenesis of degenerative PTRCT is multifactorial. Whereas articular sided PTRCT is usually caused by internal causes, both internal and external causes have important role in bursal sided PTRCT. A detailed history, clinical examination and magnetic resonance angiography are used in the diagnosis of PTRCT. Treatment of PTRCT is chosen based on age, demands of patients, causes and depth of tear. In most patients, non-operative treatment should be initiated. Whereas debridement can be done for less than 6 mm of articular sided PTRCT and in less than 3 mm of bursal sided PTRCT, repair techniques should be considered for higher grade PTRCT than that. Although the effect of acromioplasty is not clear, acromioplasty may be performed when the extrinsic causes appear to be the cause of tear. Either transtendon repair technique or repair after tear completion provided satisfactory clinical outcomes in treatment of articular sided PTRCT.

• Journal of Chest Surgery
• /
• v.22 no.5
• /
• pp.739-747
• /
• 1989

Between September 1986, and August 1989, eight infants underwent operation for repair of coarctation of the aorta in the first year of life. The patients included 7 males and 1 female ranging in age 19 days and 9 months. Weights ranged from 3.5 Kg to 7 Kg [mean 5 Kg]. All patients had preductal coarctation of the aorta. Each infant had associated cardiac anomalies, including ventricular septal defect [7 infants] and patent ductus arteriosus [5 infants]. All had intractable congestive heart failure, despite aggressive medical therapy. Pressure gradient across the coarctation ranged from 10 mmHg to 60 mmHg. Operative techniques were subclavian flap aortoplasty in five cases, Gore-Tex patch aortoplasty in three cases. In addition to coarctation repair, six infants had concomitant banding of the pulmonary artery. Four infants required ventilator support for several days. There was no operative death. Complications developed in two. One infant had tracheal stenosis after a tracheostomy. Another infant had restenosis of the aorta revealed by cardiac catheterization 30 months after surgery. The pressure gradient was 30 mmHg, necessitating balloon dilatation aortoplasty. Results were satisfactory. During follow up, we performed total correction procedures [patch closure of the ventricular septal defect, infundibulectomy, pulmonary valvotomy and pulmonary artery angioplasty] in one case. Continuing follow-up finds all patients in good condition.

• Archives of Plastic Surgery
• /
• v.46 no.2
• /
• pp.114-121
• /
• 2019

Background Bilateral cleft lip deformity is much more difficult to correct than unilateral cleft lip deformity. The complexity of the deformity and the sensitive relationships between the arrangement of the muscles and the characteristics of the external lip necessitate a comprehensive preoperative plan for management. The purpose of this study was to evaluate the repair of bilateral cleft lip using the Byrd modification of the traditional Millard and Manchester methods. A key component of this repair technique is focused on reconstruction of the central tubercle. Methods Fourteen patients with mean age of 5.7 months presented with bilateral cleft lip deformity and were operated on using a modification of the Millard and Manchester techniques. Patients with a very wide cleft lip and protruded or rotated premaxilla were excluded from this study. We analyzed 30 normal children for a comparison with our patients in terms of anthropometric measurements. Results By the end of the follow-up period (between 9 and 19 months), all our patients had obtained a full central segment with adequate white roll in the central segment and a deep gingivolabial sulcus, and we obtained nearly normal anthropometric measurements in comparison with age-matched normal children. Conclusions We recommend this modified technique for the treatment of bilateral cleft lip deformity.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.45 no.3
• /
• pp.18-30
• /
• 2022

Predicting remaining useful life (RUL) becomes significant to implement prognostics and health management of industrial systems. The relevant studies have contributed to creating RUL prediction models and validating their acceptable performance; however, they are confined to drive reasonable preventive maintenance strategies derived from and connected with such predictive models. This paper proposes a data-driven preventive maintenance method that predicts RUL of industrial systems and determines the optimal replacement time intervals to lead to cost minimization in preventive maintenance. The proposed method comprises: (1) generating RUL prediction models through learning historical process data by using machine learning techniques including random forest and extreme gradient boosting, and (2) applying the system failure time derived from the RUL prediction models to the Weibull distribution-based minimum-repair block replacement model for finding the cost-optimal block replacement time. The paper includes a case study to demonstrate the feasibility of the proposed method using an open dataset, wherein sensor data are generated and recorded from turbofan engine systems.

• Journal of architectural history
• /
• v.18 no.4
• /
• pp.63-79
• /
• 2009

Since the 1970's, UNESCO and ICOMOS have adopted or emphasized on the principles of historic preservation. One of them is what to require a repair have not to be repaired beyond the limits of the features and techniques to have been born in those days of establishment. On the premise, this paper is to examine the materials and technique of lime plaster work in order for roof ridge, and for bond paste of stones and bricks in government constructions in the late of Joseon dynasty(17~19c). The result of this examination will come up with a basic conformity in the case of repairing the building established in the late of Joseon dynasty. This paper is carried out for the proper repair and restoration of architectural cultural properties. Construction reports and other documents in those days are examined for the study. Following conclusions have been reached through the study. The components of old plaster mixtures which agglutinate stones each other were quicklime, perilla oil, and paper fiber. The components of old plaster mixtures which point joint of black bricks consisted of slaked lime, perilla oil, paper fiber, and cereal starch. These components were the same as coat surface of roof ridges. In the case of times, one of the following sand, white clay, sap of boiled elm bark was added to these components for the purpose of high efficiency. These materials and techniques which applied to plaster work of those buildings had developed in the process of making royal tombs. But these materials and techniques were quite different from the present.