• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.6
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• pp.548-552
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• 2010

The submandibular gland is the second largest major salivary gland, which secretes 40% of the total daily saliva. Owing to its anatomic characteristics as well as the high viscosity and basicity of the saliva, sialolithiasis is found most commonly in the submandibular gland. Sialolithiasis that cannot be treated by conservative treatment is conventionally removed by an excision of the submandibular gland. Generally, an excision of the submandibular gland is performed via an extra-oral approach but the disadvantages of this treatment include a risk of injuring the facial nerve and scar formation. Case reports have revealed an even less invasive intraoral surgical technique for the removal of sialolith that does not affect the submandibular gland function. The functional recovery of the gland, complications and recurrence rates after surgery with this conservative intraoral procedure were all successful. We report 5 patients from the department of Oral and Maxillofacial Surgery at Dental Hospital, Yonsei University, who had undergone a resection of the sialolith though the intraoral approach with successful results.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.10
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• pp.1145-1152
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• 2014

The RFID (Radio-Frequency Identification) system is a technology to discern things by radio and an epoch-making new method to improve product management such as distribution, transport, mobilization, inventory control. However, RFID, which uses radio, is at risk for information leakage and falsification due to the vulnerability of security of the communication section. We designed the new authentication protocol by applying the tent map, which is the representative complex systems, to the RFID communication system. A more solid and simple authentication system was designed by applying the initial value sensitivity and irregularity, which are the representative characteristics of the complex system, to the reader and tag of RFID. The purpose of this paper is to verify the usability of the RFID authentication protocol design that uses the nonlinear system shown in this thesis by the new system differentiated from the authentication system that depends on the existing hash function or random numbers.

• Journal of the Korean Geotechnical Society
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• v.30 no.10
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• pp.55-65
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• 2014

Recent researches on debris flow is focused on understanding its movement mechanism and building a numerical simulator to predict its behavior. However, previous simulators emulating fluid-like debris flow have limitations in numerical stability, geometric modeling and application of various boundary conditions. In this study, depth integration is applied to continuity equation and force equilibrium for debris flow. Thickness of sediment, and average velocities in x and y flow direction are chosen for main variables in the analysis, which improve numerical stability in the area with zero thickness. Petrov-Galerkin formulation uses a discontinuous test function of the weighted matrix from DG scheme. Presented mechanical constitutive model combines fluid and granular behaviors for debris flow. Effects on slope angle, inducing debris height, and bottom friction resistance are investigated for a simple slope. Numerical results also show the effect of embankment at the bottom of the slope. Developed numerical simulator can assess various risk factors for the expected area of debris flow, and facilitate embankment design in order to minimize damage.

• The Korean Journal of Nuclear Medicine
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• v.25 no.2
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• pp.177-185
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• 1991

Dipyridamole thallium imaging is one of the most widely accepted means of evaluating patients with suspected or known coronay artery disease. The results of thallium imaging help diagnose coronary artery disesse (CAD), determine the hemodynamic significance of coronary stenosis, evaluate viability of myocardium, assess the outcome of therapeutic interventions and stratify patients according to their risk for luther cardiac events. An increased lung thallium uptake and transient LV dilation has been reported as poor prognostic indicator and associated with extensive and severe coronary artery disease. We quantitated lung/heart uptake ratio (l/HUR) and transient left ventricular dilation ratio in 44 patients and 17 controls undertaking dipyridamole thallium-201 scintigraphy. The results are as follows: 1) The lung/heart uptake ratio was high in patients with CAD and which became higher according to increasing number of diseased vessel. The L/HUR of patients with low LVEF (<35%) was lower than those with normal LVEF. 2) Transient left ventricular dilation ratio of CAD patients had no close relation between numbers of diseased vessels and was not higher than normals. But transient left ventricular dilation ratio of patients with myocardial infartion was higher than normals. We concluded that lung/heart uptake ratio seems to be sensitive marker for severity of CAD and myocardial function, but transient left ventricular dilation ratio alone is not sufficient to be a marker for severe and extensive CAD.

• Explosives and Blasting
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• v.36 no.1
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• pp.20-33
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• 2018

A locally damaged structure is a structure that cannot be reused due to having parts that have lost their structural function as a result of abnormal load across the interior or exterior of the structure. The causes of the abnormal load occurrences can be classified into natural disaster and artificial disaster. Locally damaged structures caused by this abnormal load have risk factors that may lead to the possibility of additional secondary collapses, so such structures require immediate and complete dismantling. The case presented in this study involves the application of explosive demolition to a steel truss structured bridge in the Philippines that was damaged due to construction failures and the hurricane. Although shaped charges were needed in explosive demolitions, difficulties in locally obtaining such material. So, we made a charge container to charging of emulsion explosive during the explosive demolition. The explosive demolition resulted in the vertical free fall of the mid-section of the bridge and the free fall rotating of the both end section of the bridge. The neighboring posts and bridge piers did not show signs of damages, while post-demolition fragmentation of removed parts was found to be satisfactory.

• Journal of Marine Bioscience and Biotechnology
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• v.12 no.1
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• pp.1-10
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• 2020

Asthma is a complex inflammatory disease of the lung characterized by variable airflow obstruction, airway hyperresponsiveness, airway inflammation, and reduction of respiratory function. Its prevalence and incidence are increasing because of the effect of various environmental and lifestyle risk factors. Steroid inhalation, long-acting agonists, and other synthetic drugs are used for the treatment of this disease. However, they have some side effects and show unsatisfied result and response after treatment. Therefore, many researchers have focused on the development of natural product-related treatment for asthma to suppress the side effects and unsatisfied results. Seaweeds contain various bioactive compounds with anti-inflammatory, antibacterial, and anti-oxidant activities. Thus, we investigated the asthma treatment-related literature using marine algae via the Google scholar search engine. Consequently, the literature is rarely investigated, but is increasing steadily. The literature was performed as a comparison study with an ovalbumin-induced group or drug-treated group, and investigated the antiasthma activity of algae ethanol extract. Although many researchers have studied marine algae-derived therapeutic agents for asthma, the amount of literature is rare compared with those of herbal medicine-derived therapeutic agents. Conclusively, we suggest that many researchers should investigate and develop algae-derived therapeutic agents for asthma treatment.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.1
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• pp.115-122
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• 2011

Recently, we have proposed a hypothesis that spinal structures have a stress sensor driving feedback mechanism, In the human spine, spinal structure could react to modify muscular action in such a way so as to equalize stress at the disc, therefore reduce the risk of injury, In this analysis, abdominal muscle and abdominal pressure, which were not included in the previous study, were added to identify those effects in spine stability during upright stance posture for the case where the intervertebral disc plays the role of mechanoreceptor, The musculoskeletal FE model was consisted with detailed whole lumbar spine, pelvis, sacrum, coccyx and simplified trunk model. Muscle architecture with 46 local muscles containing paraspinal muscle and 6 rectus abdominal muscles were assigned according to the acting directions. The magnitude of 4kPa was considered for abdominal pressure. Minimization of the nucleus pressure deviation and annulus fiber average tension stress deviation was chosen for cost function. Developed model provide nice coincidence with in-vivo measurement (nucleus pressure). Analysis was conducted according to existence of co-activation of abdominal muscle and abdominal pressure. Antagonistic activity of abdominal muscle produced stability of spinal column with relatively small amount of total muscle force. In contrast to the abdominal muscle, effect of abdominal pressure was not clear that was partly depending on the assumption of constant abdominal pressure.

• Journal of Preventive Medicine and Public Health
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• v.41 no.5
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• pp.323-330
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• 2008

Objectives : This study was conducted to examine the mediating function of body weight perception (BWP) on the relationship between body mass index (BMI) and unhealthy weight control behaviors (UWCB: e.g., fasting, or taking diet pills or laxatives) and between BMI and depressed mood, and to explore the effect of distorted BWP on UWCB and depressed mood among adult women. Methods : A regionally representative sample of 8,581 women aged 20-64 years residing in Seoul, the capital of Korea, completed the 2001 Seoul Citizens Health Indicator Survey which provides self-reported information about height, weight, BWP, UWCB, depressed mood, demo graphic/socioeconomic characteristics, and health-related behaviors. Data were analyzed using bivariate and multivariate logistic regression. Results : BMI was significantly associated both with UWCB and depressed mood, even controlling for all covariates. However, the magnitude and significance of each association was considerably attenuated when BWP was taken into account, indicating that BWP functioned, in part, as a mediator between BMI and UWCB and between BMI and depressed mood, respectively. Among the combinations of BMI and BWP, women who perceived themselves to be heavier than their actual BMls appeared more likely to use UWCB, whereas women who had a distorted BWP, either underestimation or overestimation as compared with their BMIs, tended to be at greater risk for depressed mood than those who had an undistorted BWP. Conclusions : These findings suggest that how women perceive their body weight may be an important predictor and/or mediator of UWCB and depressed mood among adult Korean women.

• Childhood Kidney Diseases
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• v.13 no.1
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• pp.1-13
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• 2009

Type 1 diabetes mellitus commonly occurs in childhood and adolescence, although the prevalence of type 2 diabetes mellitus in these age groups is now being increased in the western world and Korea. Diabetic nephropathy developing in 15-25% of subjects with type 1 diabetes mellitus and in similar or higher percentage of type 2 diabetes mellitus patients is the leading cause of end-stage renal disease worldwide. Although prepubertal diabetic duration may contribute less to the development of microvascular complications than pubertal and postpubertal duration, diabetic nephropathy in susceptible patients almost certainly begins soon after disease onset and may accelerate during adolescence, leading to microalbuminuria or incipient DN. Type 1 diabetes is commonly associated with a period of hyperfiltration followed by the development of persistent microalbuminuria after as little as 7-10 years of type 1 diabetes. Microalbuminuria is associated with pathologic lesions that are so advanced as to overlap with those seen in patients with overt proteinuria and declining kidney function, therefore, microalbuminuria currently considered the best clinical indicator of overt diabetic nephropathy risk. This review covers the natural history and renal manifestations of diabetic nephropathy in children and adolescents.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.57-62
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• 2011

Modern chemical plants including petroleum refinery and gas industries have evolved into more complex and specialized. In these industrial complexes, it is important to maintain acceptable safety level protecting from various potential disasters caused by fire, explosion and the leakage of toxic materials. Recently possibility and consequence of accidents are increasing in the industrial process. So there is a trade-off between the plant operation efficiency and safety level. In this study SIF(Safety instrument Functions) was incorporated into SIL(Safety Integrity Levels). As a result, the safety level was upgraded by designing resonable allocation of safety instruments.