• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.5A
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• pp.317-324
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• 2012

Physical layer network coding (PNC) was first introduce by Zhang et al. for two-way relay channels (TWRCs). By utilizing the PNC, we can complete two-way communications within two time slots, instead of three time slots required in non-PNC systems. Recently, the upper and lower bounds for a bit error rate (BER) of PNC have been analyzed for fading channels. In this paper, we derive an exact BER of the PNC for the TWRC over fading channels. We determine decision regions based on the nearest neighbor rule and partition them into several wedge areas to apply the Craig's polar coordinate form for computing the BER. We confirm that our derived analysis accurately matches with the simulation results.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.2
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• pp.80-87
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• 2017

Purpose: The aim of this study was to assess the physical properties of a novel resin-based endodontic sealer, Any-Seal, in comparison with AH Plus Jet. Materials and Methods: Flow, radiopacity and compressive strength were examined according to ISO 6876/2001. For flow test, 0.05 mL of sealer was placed between glass plate and 100 g weight were applied. Ten minutes after mixing the sealers, the load was removed and the diameters of the compressed sealer discs were measured. For radiopacity, 10 mm diameter and 1 mm thickness sample were fabricated and took radiograph with an aluminum step-wedge and analyzed using imaging program. For compressive strength test, $4mm{\times}6mm$ cylindrical specimen was fabricated and tested after 24 hours and 1 week using Universal testing machine. Results: Both tested sealers were consistent with ISO 6876/2001 in the flow and radiopacity test. The flow values of both sealers were not significantly different (P > 0.05). AH Plus Jet had significantly higher radiopacity (P < 0.05). AH Plus Jet showed higher compressive strength at both time intervals (P < 0.05). Conclusion: Any-Seal showed low compressive strength until after 1 week, so its physical and biological aspect should be evaluated more before clinical use.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.78-85
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• 2018

As a numerical analysis technique to predict the radar cross section of an aircraft, a full wave method or an asymptotic method is mainly used. The full-wave method is expected to be relatively accurate compared with the asymptotic method. The asymptotic method is numerically efficient, and it is more widely used in the RCS analysis. However, the error that occurs when estimating the RCS using the asymptotic method is difficult to predict easily. In this paper, we analyze the allowable limits of physical optics by constructing a wedge-cylinder model and comparing the RCS prediction results between the method of moment and physical optics while changing the edge shape. Finally, this study proposes a criterion for allowable limit of physical optics in the RCS estimation.

• 보존과학연구
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• s.34
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• pp.6-17
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• 2013

Bukjiri Seated Rock-carved Buddha of Bonghwa is a rock carved Buddhist Statues on the Two-Mica Granite with mid-size grains. The non-destructive diagnosis on the statues showed that their surfaces had been damaged by exfoliation or granular decomposition and their physical properties are also found to be weak. In addition, the evaluation of slope stability showed that there are the possibility of toppling failure, or planar and wedge failure. So, we have recovered the physical strength and structural stability of rock using the scientific conservation treatment. We also founded that the existing shelter was damaged by the poor ventilation and water leakage. So we constructed it in a way that there is no water leakage while the ventilation is good.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.5
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• pp.463-470
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• 2016

In this paper, we introduce a method of scattering centers extraction using the polarimetric data. VIRAF software based on the PO (Physical Optics) and PTD(Physical Theory of Diffraction) were used to calculate the surface scattering and the edge or wedge scattering, respectively. In addition, by using the unitary transformation, 4-channel data based on the linear polarization basis were converted to 2-channel data based on the left/vertical-circular polarization basis, leading to data compression coherently. The scattering mechanism was analyzed in terms of the polarization states and different look angles by using the scattering center of a target extracted by the 2D RELAX algorithm.

• Current Applied Physics
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• v.18 no.11
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• pp.1185-1189
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• 2018

Thickness-dependent magnetic domain structure of ultrathin Co wedge films (0.3 nm-1.0 nm) sandwiched by Pt layers was investigated by scanning transmission x-ray microscopy (STXM) employing X-ray magnetic circular dichroism (XMCD), utilizing elliptically polarized soft x-rays and electromagnetic fields, with a spatial resolution of 50 nm. The magnetic domain images measured at the Co $L_3$ edge showed the evolution of the magnetic domain structures from maze-like form to the bubble-like form as the perpendicular magnetic field was applied. The asymmetric domain expansion of a 500 nm-scale bubble domain was also measured when the in-plane and perpendicular external magnetic field were applied simultaneously.

• Journal of the Korean Geotechnical Society
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• v.37 no.2
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• pp.33-48
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• 2021

The rock anchorage of a suspension bridge is an outstanding anchorage type from environmental and economical perspective, although it should be applied when the bearing foundation is fresh enough to resist large cable loads. In practice, geotechnical engineers have encountered difficulties in designing the anchorage structure due to the fact that the physical behaviors of rocks against cable loads have not yet been fully proved and its design method was not established yet. In this study, model tests and numerical studies were performed to evaluate the behavior of the rock anchorage system planned under hard rock layers in domestic islands, and results suggest that the shape of asymmetric rock wedges can resist the tension loads with self weight and shear resistance. Additionally, real scale trial tests were carried out to verify the accuracy of an inclined drilling penetrating hard rock layers to install tendon to the bearing plate.

• Journal of Chest Surgery
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• v.42 no.3
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• pp.344-349
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• 2009

Background: The clinical history and physical findings of the patients with spontaneous pneumothorax depend largely on the extent of the collapse of the lung and the presence of pre-existing pulmonary disease. Large primary spontaneous pneumothorax is a possible serious condition and. so more active treatment will be necessary for these patients. The therapeutic guideline for large pneumothorax remains controversial. Therefore, by assessing the clinical results of surgical treatment for large primary pneumothorax, we aim to determine the indicators of treatment. Material and Method: Among 348 patients with primary spontaneous pneumothorax and who underwent surgical treatment from August 2004 through December 2007, 58 patients who responded to treatment for a large primary pneumothorax were included in the current study. We then retrospectively evaluated the operative findings and the surgical results. The patients with a pneumothorax of 80% or more, including those patients with tension pneumothorax, were considered to have a "large pneumothorax". Most of these patients Should be treated with a 12F chest tube. Thoracoscopic wedge resection was considered for treating recurrent pneumothorax, continuous air leakage, controlateral pneumothorax and first episode pneumothorax with visible blebs (> 1cm) seen on the computed tomography. Result: There were 50 men and 8 women with a mean age of 28.2 years (range: $14\sim54$ years). The mean length of hospitalization was 5.3 days (range: $2\sim10$ days). Nine patients underwent chest tube drainage only. Forty-nine patients underwent thoracoscopic wedge resection. The mean follow up time was 27.8 months (range: $10\sim58$ months). The actual site of air leakage could be located in 35 patients (71.4%) and this was correlated with pleural adhesion (p=0.005). The initial air leakage tended to be more correlated with intra-operative air leakage, although this was not statistically significant (p=0.066). The recurrence rate was 11.1 % for the patients with chest tube drainage and 2.0% for the patients with thoracoscopic wedge resection. Conclusion: Large primary pneumothorax requires an early diagnosis and early treatment. Thoracoscopic wedge resection may help to prevent recurrence of large primary pneumothorax.

• Journal of Gastric Cancer
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• v.16 no.1
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• pp.58-62
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• 2016

Gastrointestinal stromal tumors (GISTs) are the most common primary mesenchymal neoplasms of the gastrointestinal tract and usually appear as a well-circumscribed mass. However, it may be difficult to confirm the extent of the disease for some GISTs. A 70-year-old asymptomatic female presented for a regular physical exam. An esophagogastroduodenoscopy showed a 2.0 cm protruding mass on the gastric fundus. Endoscopic ultrasound revealed an ill-defined heterogenous hypoechoic lesion ($3.0{\times}1.5cm$). A computed tomography (CT) scan demonstrated a 4.5 cm multifocal calcified mass at the gastric body as well as at the gastric fundus. Laparoscopic gastric wedge resection was performed according to the extent of multifocal calcifications that are shown on the CT. Intraoperative specimen mammography and intraoperative biopsy might be helpful to obtain a tumor-free margin. Final pathologic diagnosis was an intermediate risk GIST in multilobular form. In patients with diffuse multifocal calcifications in the stomach, the possibility of GIST should be considered.

• The Journal of Korean Society for Radiation Therapy
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• v.10 no.1
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• pp.97-101
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• 1998

In recent days, although many kinds of beam modifiers are developing and using for clinical purposes in accordance with progressing medical engineering, physical wedges are preferred to use as a beam modifier by a lot of institutions until now because of cost, complexities of dosimetry and mechanical uncertainties. According to progressing technology, available field size of wedge is more enlarger than that of old model LINAC. Because field size dependence of wedged fields increases in new model LINAC, we was trying to know that how much different PSFs are in enlarged wedged fields compared with open fields. In small or middle size of fields($4{\times}4{\sim}15{\times}15cm$), there are only a few percents of PSF variation between open and wedged fields. But there are $2{\sim}8\%\;variations\;in\;relatively\;large\;fields(20{\times}20{\sim}30{\times}40cm)$.