• Smart Structures and Systems
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• v.22 no.6
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• pp.675-687
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• 2018

In the previous studies on the porous rock strength the effect of pore number and its diameter is not explicitly defined. In this paper crack initiation, propagation and coalescence in Brazilian model disc containing a single cylindrical hole and or multiple holes have been studied numerically using PFC3D. In model with internal hole, the ratio of hole diameter to model diameter was varied between 0.03, 0.17, 0.25, 0.33, and 0.42. In model with multiple hole number of holes was different in various model, i.e., one hole, two holes, three holes, four holes, five holes, six holes, seven holes, eight holes and nine holes. Diameter of these holes was 5 mm, 10 mm and 12 mm. The pre-holed Brazilian discs are numerically tested under Brazilian test. The breakage load in the ring type disc specimens containing an internal hole with varying diameters is measured. The mechanism of cracks propagation in the wall of the ring type specimens is also studied. In the case of multi-hole Brazilian disc, the cracks propagation and b cracks coalescence are also investigated. The results shows that breaking of the pre-holed disc specimens is due to the propagation of radially induced tensile cracks initiated from the surface of the central hole and propagating toward the direction of diametrical loading. In the case of disc specimens with multiple holes, the cracks propagation and cracks coalescence may occur simultaneously in the breaking process of model under diametrical compressive loading. Finally the results shows that the failure stress and crack initiation stress decreases by increasing the hole diameter. Also, the failure stress decreases by increasing the number of hole which mobilized in failure. The results of these simulations were comprised with other experimental and numerical test results. It has been shown that the numerical and experimental results are in good agreement with each other.

• Pediatric Infection and Vaccine
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• v.26 no.1
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• pp.71-79
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• 2019

Mycoplasma pneumoniae (MP) is the most common causative agent of community-acquired pneumonia in school-aged children. An 8-year-old boy who had been diagnosed with autism looked severely ill when he presented to our hospital due to dyspnea and lethargy. He had fever and cough 7 days prior to hospitalization. He had signs and symptoms of severe respiratory distress. The percutaneous oxygen saturation was 88% at high oxygen supply. Chest radiography showed diffusely increased opacity with moderate pleural effusion. He was intubated immediately and admitted to the intensive care unit. Under the clinical impression of mycoplasmal pneumonia, intravenous clarithromycin was started. Laboratory findings showed leukocytosis, hepatitis, decreased renal function, and presence of serum MP immunoglobulin (Ig) M (+) IgG (+) and sputum MP polymerase chain reaction (+). On hospital day 2, the patient developed multiple organ failure with acute respiratory distress syndrome (ARDS). Veno-venous extracorporeal membrane oxygenation (ECMO) was performed with continuous renal replacement therapy (CRRT) and was weaned successfully. This is the first reported case of an ARDS due to MP infection complicated by multiple organ failure that was successfully treated with ECMO and CRRT in South Korea.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.2967-2972
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• 1994

The multiple character of the contact interaction and the collective behavior of elementary microcontacts play a significant role in all the processes occurring in the surface layers, including the failure due to friction and wear. The array of metal spheres compressed between flat plates has been used for simulation of the contact behavior of multiple contact of solids under normal loading. An experimental design has been made providing regular array of the spheres at the same size with different spatial order. Measurement of electrial contact resistance has been made using the equipment providing the adequate accuracy in the range of micro Ohms. The data on electrical contact resistance have been compared with theoretical predictions using the multiple contact model of constriction resistance. The effect of single spots number and array on conductivity of contact has been evaluated.

• Health Policy and Management
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• v.10 no.3
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• pp.108-128
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• 2000

The Korean government has implemented the policy for merging 141 health insurers into Korean Unified Health Insurer (KUHI) in July of 2000. The unification of multiple insurers will definitely effect the stability of financial management, equity of premium burdens and efficiency of administrative management. However, it is difficult to predict what forms the far-reaching effects of the unification would take. Thus, pursuing the unification may be express as a huge policy experiment. In order to lead the unification, which lies on a crossroad between success and failure, to the road of success, we need to infer the problems and obstacles predicted in the step-wise processes of merging organizations, finances and the systems of computing premium, and come up with the effective means to maintain the stability of financial management, to improve the equity of premium burdens and to increase the efficiency of administrative management. Thus, I first described the changes of the Korean medical insurance system, and analyzed the performances of self-employed medical insurance 1 year after the integration of societies in October of 1998. At the base of examining the stability of financial management, equity of premium burdens and efficiency of administrative management, I predicted the problems and obstacles that could occur after the unification of the multiple medical insurers, and proposed a few ways of leading the unification of the multiple medical insurers in Korea to success. The most worried factor is that insurance finance would become unstable since the expansion of premium revenues is not easy because raising the premium for all Koreans is to be difficult. In addition, the unification of insurance finance could weaken the insurer's efforts for declaring real incomes of the self-employed and increasing the collection rate of premiums from them. This weakening would be the decisive factor of lowering the equity of premium contributions between the self-employed and employees. And bureaucratization and rigidity that are unavoidable in a gigantic unified organization could lower the efficiency of administrative management. Furthermore, by having 3 labor unions in the unified organization, it is possible to experience frequent difficulties and discords among the unions and between the unions and organization. Thus, when smooth pursuing of the unification of multiple insurers gets difficult, the social expenses derived from the failure would eventually end up on all Koreans. The unification is to be performed after coming up with the ways to eradicate these worries, so that the unification of multiple insurers would step onto the road of success.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2389-2413
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• 2015

High data rates in long-term evolution (LTE) networks can affect the mobility of networks and their performance. The speed and motion of user equipment (UE) can compromise seamless connectivity. However, a proper handover (HO) decision can maintain quality of service (QoS) and increase system throughput. While this may lead to an increase in complexity and operational costs, self-optimization can enhance network performance by improving resource utilization and user experience and by reducing operational and capital expenditure. In this study, we propose the self-optimization of HO parameters based on fuzzy logic control (FLC) and multiple preparation (MP), which we name FuzAMP. Fuzzy logic control can be used to control self-optimized HO parameters, such as the HO margin and time-to-trigger (TTT) based on multiple criteria, viz HO ping pong (HOPP), HO failure (HOF) and UE speeds. A MP approach is adopted to overcome the hard HO (HHO) drawbacks, such as the large delay and unreliable procedures caused by the break-before-make process. The results of this study show that the proposed method significantly reduces HOF, HOPP, and packet loss ratio (PLR) at various UE speeds compared to the HHO and the enhanced weighted performance HO parameter optimization (EWPHPO) algorithms.

• Journal of Genetic Medicine
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• v.11 no.2
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• pp.74-78
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• 2014

Sotos syndrome (SS, OMIM 117550) is characterized by prenatal and postnatal overgrowth with multiple congenital anomalies. However, there have been few cases of growth retardation caused by renal failure from infancy. We report a case of dysplasia of the bilateral kidneys with renal failure and poor postnatal growth. A 2-month-old boy visited the emergency room owing to poor oral intake and abdominal distension. He was born at the gestational age of 38 weeks with a birth weight of 4,180 g. After birth, he had feeding difficulty and abdominal distension. Upon physical examination, his height and weight were in less than the 3rd percentile, while his head circumference was in the 50th percentile on the growth curve. He also showed a broad and protruding forehead and high hairline. Blood laboratory tests showed severe azotemia; emergent hemodialysis was needed. Abdominal ultrasonography revealed bilateral renal dysplasia with multiple cysts and diffuse bladder wall thickening. A posterior urethral valve was suggested based on vesicoureterography and abdominal magnetic resonance findings. Results of a colon study to rule out congenital megacolon did not reveal any specific findings. The conventional karyotype of the patient was 46, XY. Array comparative genomic hybridization study revealed a chromosome 5q35 microdeletion including the NSD1 gene, based on which SS was diagnosed. We describe a case of SS presenting with end stage renal disease due to posterior urethral valve. The typical somatic overgrowth of SS in the postnatal period was not observed due to chronic renal failure that started in the neonatal period.

• International Journal of High-Rise Buildings
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• v.10 no.4
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• pp.265-283
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• 2021

To ensure that fire induced collapse of a building is prevented it is important to understand the sequence of events that can lead to this event. In this paper, the initiation of collapse mechanisms of generic a multi-storey steel frame subjected to vertical and horizontal travelling fires are analysed computationally by tracking the formation of plastic hinges in the frame and generation of fire induced loads. Both uniform and travelling fires are considered. In total 58 different cases are analysed using finite element software LS-DYNA. For the frame examined with a simple and generic structural arrangement and higher applied fire protection to the columns, the results indicate that collapse mechanisms for singe floor and multiple floor fires can be each split into two main groups. For single floor fires (taking place in the upper floors of the frame (Group S1)), collapse is initiated by the pull-in of external columns when heated beams in end bays go into catenary action. For single floor fires occurring on the lower floors(Group S2), failure is initiated (i.e. ultimate strain of the material is exceeded) after the local beam collapse. Failure in both groups for single floor fires is governed by the generation of high loads due to restrained thermal expansion and the loss of material strength. For multiple floor fires with a low number of fire floors (1 to 3) - Group M1, failure is dominated by the loss of material strength and collapse is mainly initiated by the pull-in of external columns. For the cases with a larger number of fire floors (5 to 10) - Group M2, failure is dominated by thermal expansion and collapse is mainly initiated by swaying of the frame to the side of fire origin. The results show that for the investigated frame initiation of collapse mechanisms are affected by the fire type, the number of fire floors, and the location of the fire floor. The findings of this study could be of use to designers of buildings when developing fire protection strategies for steel framed buildings where the potential for a multifloor fire exists.

• Bulletin of the Korean Mathematical Society
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• v.56 no.6
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• pp.1435-1445
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• 2019

We consider a checkpointing model for silent errors, where a checkpoint is taken every fixed number of verifications. Assuming generally distributed i.i.d. inter-occurrence times of errors, we derive the reliability of the model as a function of the number of verifications between two checkpoints and the duration of work interval between two verifications.

• Journal of Korean Critical Care Nursing
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• v.6 no.2
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• pp.51-64
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• 2013

Purpose: This study was to analyze adherence to self-care behaviors and identify factors affecting the adherence behaviors among inpatients with heart failure. Methods: A total 94 hospitalized inpatients from three hospitals participated in a survey. Data were collected using structured self-reported questionnaire from November 28, 2011 to March 31, 2013 and analyzed using frequency, t-test, ANOVA, Pearson's correlation coefficients and stepwise multiple regression. Results: The score of adherence to self-care behaviors among inpatients with heart failure was $26.02({\pm}8.84)$. Factors related to the adherence to self-care behaviors were living with spouse (t=-2.47, p=.019), functional state (t=2.18, p=.034), heart failure knowledge (r=-.49, p<.001), social support (r=-.35, p<.001), self-control (r=-.25, p=.016), and self-care confidence (r=-.24, p=.019). The factors affecting adherence to self-care behaviors were heart failure knowledge, self-care confidence, and social support. These factors explained 32% of the variance in adherence to self-care behaviors. Conclusion: The adherence to self-care behaviors with heart failure can be improved if heart failure knowledge, self-care confidence, and social support are improved. Therefore, developing a nursing intervention program for patient with heart failure that is considered these factors leads to improve quality of life and prevent readmission.

• Structural Engineering and Mechanics
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• v.25 no.3
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• pp.347-363
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• 2007

A novel methodology, referred to as Auxiliary Domain Method (ADM), allowing for a very efficient solution of nonlinear reliability problems is presented. The target nonlinear failure domain is first populated by samples generated with the help of a Markov Chain. Based on these samples an auxiliary failure domain (AFD), corresponding to an auxiliary reliability problem, is introduced. The criteria for selecting the AFD are discussed. The emphasis in this paper is on the selection of the auxiliary linear failure domain in the case where the original nonlinear reliability problem involves multiple objectives rather than a single objective. Each reliability objective is assumed to correspond to a particular response quantity not exceeding a corresponding threshold. Once the AFD has been specified the method proceeds with a modified subset simulation procedure where the first step involves the direct simulation of samples in the AFD, rather than standard Monte Carlo simulation as required in standard subset simulation. While the method is applicable to general nonlinear reliability problems herein the focus is on the calculation of the probability of failure of nonlinear dynamical systems subjected to Gaussian random excitations. The method is demonstrated through such a numerical example involving two reliability objectives and a very large number of random variables. It is found that ADM is very efficient and offers drastic improvements over standard subset simulation, especially when one deals with low probability failure events.