• Proceedings of the KHMA Conference
• /
• 2001.11a
• /
• pp.49-70
• /
• 2001

• The Journal of the Korean dental association
• /
• v.45 no.12 s.463
• /
• pp.733-741
• /
• 2007

• 건설안전세미나
• /
• s.7
• /
• pp.147-185
• /
• 1996

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.2
• /
• pp.68-75
• /
• 2015

This study established key factors causing deck slab deterioration based on GPR database of 747 highway bridges, and predicted deck slab damage rates with respect to bridge service life. To minimize the influence of bridge service life on deck slab deterioration, the deck slab damage rate database was corrected based on a linear regression model of bridge service life vs. deck slab damage rate. The corrected deck slab damage rates were analyzed to determine correlation considering the number of snowy days, the amount of snowfalls, the number of freeze-thaw days, average winter temperature, altitude, the amount of deicing chemicals and equivalent traffic volume, and then both the number of freeze-thaw days and the amount of deicing chemicals were determined to be key factors causing deck slab deterioration. The complex deterioration considering both key factors was represented deck slab damage rate charts, and the average deck slab life was derived. The results of this study will be used as a guideline for highway bridge maintenance to identify the progress of deck slab deterioration for a given bridge and predict the time required deck slab rehabilitation.

• Journal of the Korean Data and Information Science Society
• /
• v.20 no.5
• /
• pp.797-807
• /
• 2009

In a case of an automobile rear-end collision, scale of the collision which are the extent of vehicle damage and the injury of the passenger is affected by the speed change. Based on the photographic interpretation of the actual accident cases in the Seoul and the Incheon area, this study measured the depth of crush and calculated the speed change from the statement data of the accident and speed, and also injury data such as diagnosis, hospitalization days are collected. The period of hospitalization and diagnostics claimed proves to have no statistical correlation with the depth of vehicle crush and speed change. Based on the statistical analysis from this study and previous foreign studies, we found that there have been 78.1% of personal accidents didn't reach the injury threshold. There should be objective information on the scale of accident accepting the claims-to-be-injured in the future, and application of injury threshold level suggested are considered to be very useful.

• Explosives and Blasting
• /
• v.38 no.1
• /
• pp.14-22
• /
• 2020

Bit damage is one of the primary causes of decreasing drilling efficacy. Nevertheless the management of bit ware and failure are often left for field engineers' experience. Thus it is imperative to establish a proper system to predict and manage the bit damage during the rock drilling process. In this study, the drilling sound signal has been recorded and analyzed using wavelet transform analysis to identify the exact moment of bit failure. Through the analysis wavelet time-frequency spectrums have been constructed and an abnormal point has been identified with 0.9 of wavelet transform value at the 652.8s on a frequency band around 500Hz. Furthermore it is also observed that the penetration rate of the damaged bit has been decreased to 23mm/s which is 9mm/sec lower than the average of undamaged bit. The study verifies that wavelet transform analysis can be used to build a system to diagnose the bit damage while drilling.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.2
• /
• pp.83-93
• /
• 2013

Generally the capacities of electric power transmission tower's members are improved by increasing their stiffness nature through injection of grout or attachment of other structural stiffeners. Those are for upgrading their axial strength by fulfillment of proper materials into pipe members, increment of member dimension by addition of section, or a combination of the two. However the use of innovative and unusual procedures would be positively recommended for getting more stable state. It is that buckled members are replaced with lengthened and strengthened members. In providing the structural restoration procedures for the existing electric power transform tower whose main members have been damaged due to unequal foundation settlement, structural damage inspection works and numerical analyses for the damaged one and the restored one were done in detail at first. secondarily member-exchanging works using a newly-generated jacking system and strengthened members were achieved. This figures are to point clearly to inherent advantages attending the management of the towers.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.7 no.4
• /
• pp.121-128
• /
• 2003

In recent years, various artificial neural network algorithms are used in the damage assessment of civil infrastructures. So far, many researchers have used the artificial neural network as a pattern classifier for the structural damage assessment but, in this paper, the neural network is used as a structural reanalysis tool not as a pattern classifier. For the model updating using the optimization algorithm, the summation of the absolute differences in the structural vibration modes between undamaged structures and damaged ones is considered as an objective function. The stiffness of structural components are treated as unknown parameters to be determined. The structural damage detection is achieved using model updating based on the optimization techniques which determine the estimated stiffness of components minimizing the objective function. For the verification of the proposed damage identification algorithm, it is numerically applied to a simply supported bridge model.

• Tuberculosis and Respiratory Diseases
• /
• v.46 no.4
• /
• pp.586-590
• /
• 1999

Tracheobronchial rupture is one of the less-common injuries associated with blunt chest trauma. The diagnosis of tracheobronchial rupture is not easy, but failure to diagnosis may lead to death or long-term disability. Early diagnosis and appropriate management can reduce the mortality and morbidity. Bronchoscopy is the diagnostic method of choice for patients with tracheobronchial rupture. We report a case of tracheal rupture after blunt chest trauma. A 40-year-old man was transferred to our hospital for dyspnea after blunt chest trauma. He was promptly diagnosed as tracheal rupture by fiberoptic bronchoscopy and chest computed tomogram. He was successfully managed by thoracotomy and primary repair.

• Journal of the Korean Orthopaedic Association
• /
• v.55 no.6
• /
• pp.540-544
• /
• 2020

Unstable pelvis ring trauma can accompany urologic injuries such as bladder, ureter, or urethral injuries. In very rare cases, testicular dislocation can accompany a pelvic ring injury. Testicular dislocation causes pain, but can be regarded as the pain caused by pelvic ring injury. If not detected early, testicular dislocation may result in gangrenous testes. The authors report a case of pelvic ring injury with testicular dislocation.