• Geomechanics and Engineering
• /
• v.22 no.5
• /
• pp.461-473
• /
• 2020

Natural rock mass contains defects of different shapes, usually filled with inclusions such as clay or gravel. The presence of inclusions affects the failure characteristics and mechanical properties of rock mass. In this study, the strength and failure characteristics of rock with inclusions were studied using the particle flow code under uniaxial compression. The results show that the presence of inclusions not only improves the mechanical properties of rock with defects but also increases the bearing capacity of rock. Circular inclusion has the most obvious effect on improving model strength. The inclusions affect the stress distribution, development of initial crack, change in crack propagation characteristics, and failure mode of rock. In defect models, concentration area of the maximum tensile stress is generated at the top and bottom of defect, and the maximum compressive stress is distributed on the left and right sides of defect. In filled models, the tensile stress and compressive stress are uniformly distributed. Failing mode of defect models is mainly tensile failure, while that of filled models is mainly shear failure.

• Journal of Chest Surgery
• /
• v.23 no.1
• /
• pp.41-48
• /
• 1990

Thirteen patients underwent repair of atrioventricular septal defect [AVSD] from January 1980 to July 1989 at Kyungpook National University Hospital. Two patients had complete AVSD [Rastelli type A] and eleven patients had partial AVSD [ostium primum atrial septal defect and cleft of anterior mitral leaflet]. In all the patients of partial AVSD, atrial septal defect was closed with Dacron patch and the mitral cleft was approximated with interrupted simple sutures. In one patient of complete AVSD, one patch technique was used to close the atrial and ventricular septal defect, and in the other patient of complete AVSD, two patch technique was used. In six patients, there were associated anomalies; four had isolated ostium secundum ASD, two had patent foramen ovale. Postoperative complete A-V block was noted in a patient of partial AVSD, but it was returned to 1st degree A-V block 30 months later and in another case of partial AVSD, severe congestive heart failure [NYHA functional class IV] due to residual mitral insufficiency was developed postoperatively, but this patient was recovered to the state of functional class I after receiving mitral valve replacement. There was one hospital death [8 %] resulting from low cardiac output.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.1
• /
• pp.192-199
• /
• 2016

With changes in insulated defects, the environment, and so on, new partial discharge (PD) data are highly different from the original samples. It leads to a decrease in on-line recognition rate. The UHF signal and pulse current signal of four kinds of typical artificial defect models in gas insulated switchgear (GIS) are obtained simultaneously by experiment. The relationship map of ultra-high frequency (UHF) cumulative energy and its corresponding apparent discharge of four kinds of typical artificial defect models are plotted. UHF cumulative energy and its corresponding apparent discharge are used as inputs. The support vector machine (SVM) incremental method is constructed. Examples show that the PD SVM incremental method based on simulated annealing (SA) effectively speeds up the data update rate and improves the adaptability of the classifier compared with the original method, in that the total sample is constituted by the old and new data. The PD SVM incremental method is a better pattern recognition technology for PD on-line monitoring.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.11
• /
• pp.1315-1321
• /
• 2013

This study presents a prognostic technique for the damage state of a ball bearing. A stochastic bearing fatigue defect-propagation model is applied to estimate the damage progression rate. The damage state and the time to failure are computed by using RMS data from noisy acceleration signals. The parameters of the stochastic defect-propagation model are identified by conducting a series of run-to-failure tests for ball bearings. A regularized particle filter is applied to predict the damage progression rate and update the degradation state based on the acceleration RMS data. The future damage state is predicted based on the most recently measured data and the previously predicted damage state. The developed method was validated by comparing the prognostic results and the test data.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2001.02a
• /
• pp.31-31
• /
• 2001

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.29 no.2
• /
• pp.82-88
• /
• 2017

There are main issues of defect type that condensation, concrete crack and noise in apartment buildings. Especially, according to the Apartment Defect Dispute Mediation Committee in Korea (ADDMC) at Ministry of Land Infrastructure and Transport in Korea (MLIT), condensation defects are great importance (14 percent) on whole number of reported cases of faults from 2015 in Korea. Most condensation defects have many different causes that take a toll on the resident's life and space. So it is very important to early detection and repair. For preventing the condensation in apartment buildings, there are building codes in Korea such as 'Standard of Method and Judgment for Apartment defect of investigation, Repair cost Estimate'. This research aims to study on the improvement of preventing the condensation aforementioned korea standard. Types and characteristics (opaque wall, windows, doors) of cause of occurrence and existing state condensation defect is analyzed from evaluation of real application 100 case in 2015 ADDMC data.

• 한국전기화학회:학술대회논문집
• /
• 2003.10a
• /
• pp.8-8
• /
• 2003

• Korean Journal of Materials Research
• /
• v.32 no.9
• /
• pp.396-402
• /
• 2022

In this study, surface roughness and interfacial defect characteristics were analyzed after forming a high-k oxide film on the surface of a prime wafer and a test wafer, to study the possibility of improving the quality of the test wafer. As a result of checking the roughness, the deviation in the test after raising the oxide film was 0.1 nm, which was twice as large as that of the Prime. As a result of current-voltage analysis, Prime after PMA was 1.07 × 10 A/cm² and Test was 5.61 × 10 A/cm², which was about 5 times lower than Prime. As a result of analyzing the defects inside the oxide film using the capacitance-voltage characteristic, before PMA Prime showed a higher electrical defect of 0.85 × 10¹² cm^-2 in slow state density and 0.41 × 10¹³ cm^-2 in fixed oxide charge. However, after PMA, it was confirmed that Prime had a lower defect of 4.79 × 10¹¹ cm^-2 in slow state density and 1.33 × 10¹² cm^-2 in fixed oxide charge. The above results confirm the difference in surface roughness and defects between the Test and Prime wafer.

• The KIPS Transactions:PartD
• /
• v.15D no.4
• /
• pp.523-530
• /
• 2008

There are many defects that cause the process improvement of lifecycle problems during software development. This paper propose the management method of risk items that removes and manages the lifecycle problems as well. For the similar projects, we can estimate defects and prepare to solve them by using domain expert knowledge and the state analysis of defect items, which can greatly improve the software process. This research provides solution of management of risk items problem and detection of defect transition and its prevention and causes that happen on software development. Also, In this paper propose to making quantity of degree and transition phase.

• Journal of the Korean Society of Safety
• /
• v.38 no.6
• /
• pp.1-8
• /
• 2023

The health state of the oil transformer is evaluated by the age of use and the state of internal defects. Mineral Oil, used as an insulator for oil transformers, creates specific gases and compounds through chemical reactions caused by heat, moisture, and partial discharge inside the transformer. It is possible to determine the aging and defect of the transformer through these gases and compounds. So, it is an important indicator to evaluate the health of a transformer. In this study, factors for assessing the health of transformers were hierarchically categorized, and key factors for each hierarchy were selected for design weighting. These weights were determined through surveys conducted with experts in the fields of transformer design, operation, and quality. For the health of a transformer, defect-related factors are approximately three times more important than factors related to aging. Additionally, defect-related factors showed a higher weighting for gases generated at high temperatures. Furthermore, Furan was determined to have a high weight, directly associated with insulating paper aging. Based on these findings, a health index was proposed, and a comparative analysis was conducted by categorizing 40 operational transformers into normal and comparison groups to evaluate and validate it.