• International Journal of Naval Architecture and Ocean Engineering
• /
• v.8 no.6
• /
• pp.577-588
• /
• 2016

Due to the uncertainties related to the flaw assessment parameters, such as flaw size, fracture toughness, loading spectrum and so on, the probability concept is preferred over deterministic one in flaw assessment. In this study, efforts have been made to develop the reliability based flaw assessment procedure which combines the flaw assessment procedure of BS7910 and first-and second-order reliability methods (FORM/SORM). Both crack length and depth of semi-elliptical surface crack at weld toe were handled as random variable whose probability distribution was defined as Gaussian with certain means and standard deviations. Then the limit state functions from static rupture and fatigue perspective were estimated using FORM and SORM in joint probability space of crack depth and length. The validity of predicted limit state functions were checked by comparing it with those obtained by Monte Carlo simulation. It was confirmed that the developed methodology worked perfectly in predicting the limit state functions without time-consuming Monte Carlo simulation.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.49 no.2
• /
• pp.214-223
• /
• 2016

Joint time-frequency images of the broadband acoustic echoes of six fish species were obtained using the smoothed pseudo-Wigner-Ville distribution (SPWVD). The acoustic features were extracted by changing the sliced window widths and dividing the time window by a 0.02-ms interval and the frequency window by a 20-kHz bandwidth. The 22 spectrum amplitudes obtained in the time and frequency domains of the SPWVD images were fed as input parameters into an artificial neural network (ANN) to verify the effectiveness for species-dependent features related to fish species identification. The results showed that the time-frequency approach improves the extraction of species-specific features for species identification from broadband echoes, compare with time-only or frequency-only features. The ANN classifier based on these acoustic feature components was correct in approximately 74.5% of the test cases. In the future, the identification rate will be improved using time-frequency images with reduced dimensions of the broadband acoustic echoes as input for the ANN classifier.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.6
• /
• pp.22-27
• /
• 1997

In general, the load which acts on the structure is almost independent of time in many locations. In this case. It is difficult to estimate the life with the service load history, because the structure is on the multi- axial and multi-point loading states. In this study, the service load of the excavator which is widely used in industry field was calculated using measured cylinder pressures and displacements. The fatigue life was estimated using the multi-axial and multi-point load counting method. Service load history of 4 pin joint which act independently each other is yielded by mult-axial and multi-point load counting method. The stress spectrum is yielded by superposition of the results of FEM stress analysis applied unit load. Palm- gren-Miner's cumulative Damage is 0.000804 for Von Mises equivalent stress sequence by one side fillet weld S-N curve. This result agress with Bench test results. As a result of this study, the fatigue life esti- mation using the multi-axial and multi-axial and multi-point load counting method is useful.

• Archives of Plastic Surgery
• /
• v.44 no.5
• /
• pp.444-448
• /
• 2017

As many people keep small dogs as pets, dog bites are common injuries, accounting for approximately 80%-90% of all animal bite injuries. These injuries usually occur on the upper extremities, most commonly on the fingers. Most of these injuries appear as simple lacerations or abrasions of the skin. Common symptoms include inflammatory reactions of the soft tissue, such as pain, swelling, erythema, and cellulitis. However, the complications of small dog bites may include joint or cartilage injuries, including acute osteomyelitis. Once osteomyelitis develops, it is difficult to diagnose since it has a latency period of approximately 2 weeks. Plain radiography, magnetic resonance imaging, and 3-phase bone scans should be performed when acute osteomyelitis is suspected, and broad-spectrum empiric antibiotic treatment should be administered for approximately 8-12 weeks. We report 3 very rare cases of acute osteomyelitis that occurred after a dog bite injury.

• 대한방사선방어학회:학술대회논문집
• /
• 2010.04a
• /
• pp.94-95
• /
• 2010

The accuracy of typical dosimeters used around high energy accelerator were proved by dose rate measurements. The experimental neutron spectrum were useful for improving high energy Monte Carlo codes by validating the implemented models. In series of this joint research the experimental data will be upgrade successively. This research program is opened to experts and students in Korea, too.

• Clinical and Experimental Pediatrics
• /
• v.56 no.5
• /
• pp.196-201
• /
• 2013

Fluoroquinolones are an important class of antibiotics that are widely used in adult patients because of their broad spectrum of activity, good tissue penetration, and oral bioavailability. However, fluoroquinolone use in children is limited because juvenile animals developed arthropathy in previous experiments on fluoroquinolone use. Indications for fluoroquinolone use in patients younger than 18 years, as stated by the U.S. Food and Drug Administration, include treatment of complicated urinary tract infections and postexposure treatment for inhalation anthrax. In Korea, the systemic use of fluoroquinolones has not been approved in children younger than 18 years. Although concerns remain regarding the adverse musculoskeletal effects of fluoroquinolones in children, their use in the pediatric population has increased in many circumstances. While pediatricians should be aware of the indications and adverse effects of fluoroquinolones, recent studies have shown that the risk for musculoskeletal complications in children did not significantly increase following fluoroquinolone treatment. In addition, fluoroquinolones may be particularly helpful in treating multidrug-resistant infections that have not responded to standard antibiotic therapy in immunocompromised patients. In the present article, we provide an updated review on the safety and current recommendations for using fluoroquinolones in children.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.11
• /
• pp.5253-5270
• /
• 2016

With device-to-device (D2D) communications, an inactive user terminal can be utilized as a relay node to support multi-hop communication so that connective experience of the cell-edge user as well as the capacity of the whole system can be significantly improved. In this paper, we investigate the spectrum sharing for a cooperative relay assisted D2D communication underlying a cellular network. We formulate a joint relay selection and channel assignment problem to maximize the throughput of the system while guaranteeing the quality of service (QoS) requirements of cellular users (CUs) and D2D users (DUs). By exploiting coalition formation game theory, we propose two algorithms to solve the problem. The first algorithm is designed based on merge and split rules while the second one is developed based on single user's movement. Both of them are proved to be stable and convergent. Simulation results are presented to show the effectiveness of the proposed algorithms.

• YAKHAK HOEJI
• /
• v.52 no.2
• /
• pp.101-110
• /
• 2008

Total Knee Replacement (TKR) surgery is one of the invasive procedures for patients with late-stage knee joint disorders. In the present study, economic efficiency was compared between uses of the 2nd and 3rd generation cephalosporins for the prophylaxis before and after the surgery using frequency analysis in terms of various factors such as medication costs, the number of days of antibiotic use and hospitalization due to TKR surgery. The results showed that the 3rd generation cephalosporins did not reduce the infection rate and total medication costs, but rather raised antibiotic cost in comparison with the 2nd ones. A frequent use of the 3rd ones is closely related to emergence of resistant bacterial strains. Therefore, we suggest that unnecessary prescriptions for the broad spectrum antibiotics should be avoided.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.10A
• /
• pp.1159-1166
• /
• 2004

This paper follows up the previous work on the linearly constrained, modified minimum mean-squared error(MMSE) detection for direct-sequence code-division multiple-access DS-CDMA) systems in fading channels. We find a condition to avoid the breakdown of joint modified MMSE detection and pilot symbol-aided channel estimation (PSACE). The linearly constrained, modified MMSE solution is theoretically shown to be robust against time variations in Rayleigh fading channels. This fact is consistent with the simulation results. We also show that under some conditions the linearly constrained, modified MMSE detection maximizes the output signal-to-interference-plus-noise ratio.(SINR)

• Earthquakes and Structures
• /
• v.14 no.6
• /
• pp.505-523
• /
• 2018

Static pushover analyses of typical existing reinforced concrete frames, designed according to the previous generations of design codes in Greece, have established these structures' inelastic characteristics, namely overstrength, global ductility capacity and available behaviour factor q, under planar response. These were compared with the corresponding demands at the collapse limit state target performance point. The building stock considered accounted for the typical variability, among different generations of constructed buildings in Greece, in the form, the seismic design code in effect and the material characteristics. These static pushover analyses are extended, in the present study, in the time history domain. Consequently, the static analysis predictions are compared with Incremental Dynamic Analysis results herein, using a large number of spectrum compatible recorded base excitations of recent destructive earthquakes in Greece and abroad, following, for comparison, similar conventional limiting failure criteria as before. It is shown that the buildings constructed in the 70s exhibit the least desirable behaviour, followed by the buildings constructed in the 60s. As the seismic codes evolved, there is a notable improvement for buildings of the 80s, when the seismic code introduced end member confinement and the requirement for a joint capacity criterion. Finally, buildings of the 90s, designed to modern codes exhibit an exceptionally good performance, as expected by the compliance of this code to currently enforced seismic provisions worldwide.