• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.3
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• pp.281-293
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• 2008

In the layered medium, the Sommerfeld integral must be evaluated to calculate a space domain Green's function. The real axis integration method provides stable and accurate results over wide ranges of the observation distance and the singnal frequency. But this method has the in efficiency of approximation when the field point z is changed. Also, as the amplitude of z increases, the change of the spectral domain function is more rapidly. Therefore, the approximation is difficult when z becomes larger. In this paper, we propose a method to calculate an accurate closed-form Green's function for microstrip structure by using the closed-loop integration path.

• Journal of Korean Society of Archives and Records Management
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• v.21 no.1
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• pp.75-95
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• 2021

In this study, we focused on creating plans to manage the administrative information dataset of public records in closed universities. In particular, according to various reference materials and internal materials of the institution, we studied the theoretical discussion about the dataset and figured out the management status of the closed university's dataset. Therefore, as a measure for the data management of the Comprehensive Information Management System, recording targets are selected, retention periods are determined, administrative information dataset management standards are prepared, administrative information dataset evaluation and deletion are implemented, and comprehensive management systems of closed universities are established.

• Journal of Trauma and Injury
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• v.37 no.1
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• pp.6-12
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• 2024

Purpose: Open pelvic bone fractures are relatively rare and are considered more severe than closed fractures. This study aimed to compare the clinical outcomes of open and closed severe pelvic bone fractures. Methods: Patients with severe pelvic bone fractures (pelvic Abbreviated Injury Scale score, ≥4) admitted at a single level I trauma center between 2016 and 2020 were retrospectively analyzed. Patients aged <16 years and those with incomplete medical records were excluded from the study. The patients were divided into open and closed fracture groups, and their demographics, treatment, and clinical outcomes were compared before and after 1:2 propensity score matching. Results: Of the 321 patients, 24 were in the open fracture group and 297 were in the closed fracture group. The open fracture group had more infections (37.5% vs. 5.7%, P<0.001) and longer stays in the intensive care unit (median 11 days, interquartile range [IQR] 6-30 days vs. median 5 days, IQR 2-13 days; P=0.005), but mortality did not show a statistically significant difference (20.8% vs. 15.5%, P=0.559) before matching. After 1:2 propensity score matching, the infection rate was significantly higher in the open fracture group (37.5% vs. 6.3%, P=0.002), whereas the length of intensive care unit stay (median 11 days, IQR 6-30 days vs. median 8 days, IQR 4-19 days; P=0.312) and mortality (20.8% vs. 27.1%, P=0.564) were not significantly different. Conclusions: The open pelvic fracture group had more infections than the closed pelvic fracture group, but mortality was not significantly different. Aggressive treatment of pelvic bone fractures is important regardless of the fracture type, and efforts to reduce infection are important in open pelvic bone fractures.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.5
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• pp.437-446
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• 2008

Electroglottography (EGG) is a simple and non-invasive technique for analyzing the vibratory patterns of the vocal folds by detecting impedance changes across the larynx. An abnormal electroglottogram is shown in patients who have a dysphagia associated with neuromuscular disorder. Electroglottography offers reliable informations for diagnosis of swallowing disorder and gives quantitative datas. The purpose of this study is to provide the normal value of electroglottography in normal adults. We took electroglottograms of 80 adults who have no problem in swallowing and utterance. EGG data were analyzed to find out the value of Pitch, Jitter and Closed quotient with a commercially available software. There were significant differences between a usual voice and loud voice in 3 measures on the EGG signalmean pitch, Avg. jitter, mean quotient. To get a proper electroglottography, phonation of a usual voice was better than a loud voice. Four measurements- S.D pitch, Avg. Jitter, Mean closed quotient, S.D closed quotient- were independent of sex for adult. Three measurements- Mean pitch, S.D pitch, Mean closed quotient - were independent of age for adult aged twenties to fifties. The Avg. Jitter of twenties appeared to be lower than those of forties and fifties. The S.D closed quotient of twenties appeared to be lower than those of thirties, forties and fifties.

• Archives of Craniofacial Surgery
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• v.9 no.1
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• pp.8-11
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• 2008

Purpose: The majority of nasal bone fractures have been managed by routine procedure of closed reduction, intranasal packing or intranasal Kirschner wire (K-wire) splinting. But it leaves rooms for many complaints from patients such as pain, rhinorrhea and nasal obstructioon. Another option is, of course, no packing at all. The study was initiated to assess the necessity to pack or splint the nasal bone after routine closed reduction. Methods: We analysed the medical records of 35 patients with nasal bone fracture who were operated by closed reduction in the last 2 years. We evaluated the postoperative CT scan scores and external deviation criterias 1 month after the operation. Results: The postoperative deviation criteria and postoperative CT scan score were favorable and there were no serious complications using this technique. Conclusion: The present study demonstrates that the use of packing or splinting need not be routine in the majority of cases. The risks and discomforts associated with these procedures can often be avoided.

• Journal of Power Electronics
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• v.14 no.5
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• pp.1038-1046
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• 2014

Lithium-ion batteries are widely used in hybrid and pure electric vehicles. State-of-charge (SOC) estimation is a fundamental issue in vehicle power train control and battery management systems. This study proposes a novel model-based SOC estimation method that applies closed-loop state observer theory and a comprehensive battery model. The state-space model of lithium-ion battery is developed based on a three-order resistor-capacitor equivalent circuit model. The least square algorithm is used to identify model parameters. A multi-state closed-loop state observer is designed to predict the open-circuit voltage (OCV) of a battery based on the battery state-space model. Battery SOC can then be estimated based on the corresponding relationship between battery OCV and SOC. Finally, practical driving tests that use two types of typical driving cycle are performed to verify the proposed SOC estimation method. Test results prove that the proposed estimation method is reasonably accurate and exhibits accuracy in estimating SOC within 2% under different driving cycles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.6
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• pp.1743-1758
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• 2023

Automatic modulation classification is a critical algorithm for non-cooperative communication systems. This paper addresses the challenging problem of closed-set and open-set signal modulation classification in complex channels. We propose a novel approach that incorporates a self-learning filter and center-loss in Deep Residual Shrinking Networks (DRSN) for closed-set modulation classification, and the Opendistance method for open-set modulation classification. Our approach achieves better performance than existing methods in both closed-set and open-set recognition. In closed-set recognition, the self-learning filter and center-loss combination improves recognition performance, with a maximum accuracy of over 92.18%. In open-set recognition, the use of a self-learning filter and center-loss provide an effective feature vector for open-set recognition, and the Opendistance method outperforms SoftMax and OpenMax in F1 scores and mean average accuracy under high openness. Overall, our proposed approach demonstrates promising results for automatic modulation classification, providing better performance in non-cooperative communication systems.

• Communications of the Korean Mathematical Society
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• v.29 no.3
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• pp.489-496
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• 2014

We drive a closed-form expression for the price of a European quanto call option in the double square root stochastic volatility model.

• Communications of the Korean Mathematical Society
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• v.31 no.2
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• pp.415-422
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• 2016

We derive a closed-form expression for the price of a European quanto call option when both foreign and domestic interest rates follow the Vasicek's short rate model.

• Kyungpook Mathematical Journal
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• v.45 no.1
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• pp.13-19
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• 2005

In this paper we introduce the notions of g-regularity and g-normality in fuzzy topological spaces. We obtain some characterizations and several preservation theorems of such spaces.