• Journal of information and communication convergence engineering
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• v.13 no.1
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• pp.50-55
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• 2015

We report design and simulation of a two-dimensional (2D) silicon-based nanophotonic crystal as an optical insulator to enhance the light emission efficiency of light-emitting diodes (LEDs). The device was designed in a manner that a triangular array silicon photonic crystal light insulator has a square trench in the middle where LED can be placed. By varying the normalized radius in the range of 0.3-0.5 using plane wave expansion method (PWEM), we found that the normalized radius of 0.45 creates a large band gap for transverse electric (TE) polarization. Subsequently a series of light propagation simulation were carried out using 2D and three-dimensional (3D) finite-difference time-domain (FDTD). The designed silicon-based light insulator device shows optical characteristics of a region in which light propagation was forbidden in the horizontal plane for TE light with most of the visible light spectrum in the wavelength range of 450 nm to 600 nm.

• Korean Linguistics
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• v.78
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• pp.31-54
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• 2018

'맞다(right)', which is inversely related to 'teullida', has a synonymic relationship with '같다(same)' depending on the sense. Naturally, the '같다' is usually inversely related to '다르다(be different)' as symmetry verb. The meaning of '다르다' is 'teullida' and there is a close meaning relationship network in the network of words. In other words, the process acting as a driver of the expansion of meanings based on the antonym-relation of (1)'틀리다${\leftrightarrow}$맞다', and the s?ynonym-relation of (2)'맞다 = 같다' forms a network, and the relation between them and the opposite semantics is (3)'같다=맞다${\leftrightarrow}$다르다'. And many of today's speakers speak (4)'teullida' of [difference]. Therefore, after the application of the synonymic analogy, eventually, the antonymic analogy is formed, and the word formed is 'teullida' of [difference]. This, of course, forms another type of enlargement of the meaning.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.3
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• pp.3-10
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• 2018

It's not practical to collect all information at the entire degrees of freedom of finite element model. The incomplete measurements should be expanded for subsequent analysis and damage detection. This work presents the analytical methods to expand the incomplete static or dynamic response data. Using the expanded data, introducing the concept of residual force, and minimizing the performance index expressed as the stiffness matrix and its difference before and after damage, the variation in stiffness matrix is derived. Based on the difference in the stiffness matrix, the damage detection method of structures is also provided. The validity of the proposed methods is illustrated in a numerical application, the numerical results are analyzed for applications, and the applicability of both methods is investigated.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.4_2
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• pp.815-824
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• 2024

The purpose of this study was to examine the scope of work of femergency medical technician who can directly affect the resuscitation of emergency patients at the pre-hospital stage. As a result of the main study, the overall level of the subjects' work scope expansion averaged 3.34points(out of 5points), and among the items, 'The scope of work of emergency medical personnel should be expanded by revising the Act on emergency medical cars' was the highest. As for the difference in the expansion of the scope of work of paramedics by position, 'The current telemedicine guidance system is inconvenient to use' was the highest for emergency medical technicians, and there was a statistically significant difference(p<.01). Based on this study, it is believed that repeated studies are needed to establish and generalize the scope of work of paramedics.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.4
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• pp.1-9
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• 2016

PURPOSE: The aim of this study was to examine the effects of abdominal breathing and thoracic expansion exercises on craniovertebral and cranial rotation angles in patients with rotator cuff injury. METHODS: This study enrolled 19 patients with rotator cuff injury, and ten and nine of the patients were randomly placed in abdominal breathing and thoracic expansion exercise groups, respectively. After pain treatment in each group, breathing exercise was conducted thrice a week for four weeks. The patients were recorded by using a digital camera and Image J (version 1.46, National Institutes of Health, USA), an angle measurement program, was used to analyze changes in the craniovertebral angle, cranial rotation angle, and sagittal shoulder posture. RESULTS: Statistically significant differences in the craniovertebral angle were found in both the abdominal breathing and thoracic expansion exercise groups (p<.05). A significant difference in cranial rotation angle was found in the thoracic expansion exercise group only (p<.05). No statistically significant differences in sagittal shoulder posture were found in both groups (p>.05). CONCLUSION: Although abdominal breathing and thoracic expansion exercises did not effectively change sagittal shoulder posture, the exercises were effective in improving craniovertebral and cranial rotation angles. Therefore, abdominal breathing and thoracic expansion exercises are suggested as effective exercise programs for forward head posture.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.317-320
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• 2006

• The Journal of Engineering Geology
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• v.27 no.2
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• pp.143-152
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• 2017

Recently frequent occurrence of ground subsidence cases has become social issue, and people's concern on this problem has been growing accordingly. Meanwhile, understanding on the mechanism of ground subsidence formation is not enough. Therefore, this study aims for evaluating formation mechanism of ground subsidence under various groundwater conditions through model test when groundwater and soil are leaked together. Major factors found through model tests are direction of groundwater flow, head difference around the leakage point, and strehgth of the ground to support the underground cavity. Firstly, direction of groundwater flow has an influence on the direction of cavity expansion and ground collapse. Secondly, it is observed that the speed of ground subsidence formation increases as the head difference increases. Lastly, the expansion of the cavity can eventually lead to a sudden collapse.

• The KIPS Transactions:PartB
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• v.17B no.4
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• pp.275-286
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• 2010

Reversible watermarking which can preserve the original quality of the digital contents and protect the copyright has been studied actively. Especially, in medical, military, and art fields, the need for reversible watermarking is increasing. This paper proposes a high-capacity reversible watermarking through predicted error expansion and error estimation compensation. Watermark is embedded by expanding the difference histogram between the original value and the predicted value. Differently from previous methods calculating the difference between adjacent pixels, the presented method calculates the difference between the original value and the predicted value, and that increases the number of the histogram value, where the watermark is embedded. As a result, the high capacity is achieved. The inserted watermark is extracted by restoring the histogram between the original value and the predicted value. To prove the performance, the presented algorithm is compared with other previous methods on various test images. The result supports that the presented algorithm has a perfect reversibility, a high image quality, and a high capacity.

• Imaging Science in Dentistry
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• v.39 no.3
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• pp.109-113
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• 2009

Purpose : The purpose of this study was to examine the inferior expansion of the maxillary sinus floor following maxillary molar extraction. Materials and Methods : Cone beam computed tomographic images of 59 subjects were used to evaluate the height difference of the maxillary sinus floor between extraction sites and contralateral dentate sites. The height of the maxillary sinus floor was defined as the vertical distance to the Frankfort plane from the level of the anterior nasal spine to the most inferior point of the sinus floor. We examined the difference in sinus pneumatization according to the number of missing teeth and the vertical relationship of the molar roots to the sinus floor. Results : The inferior expansion of the maxillary sinus floor was $1.20{\pm}1.86\;mm$ on the maxillary first molar and $1.90{\pm}2.42\;mm$ on the maxillary second molar. Increased expansion was observed in cases where two proximate molars were extracted. There was no significant difference in sinus pneumatization following extraction according to the vertical relationship of the molar roots to the sinus floor. Conclusion : The results of this study confirm that sinus pneumatization occurs following maxillary molar extraction. In situations where pneumatization can affect treatment after molar extraction, three-dimensional radiography should be considered.

• Journal of Korean Neurosurgical Society
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• v.64 no.2
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• pp.229-237
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• 2021

Objective : Expansion in the spinal canal area (SCA) after laminoplasty is one of the critical factors to relieve the preoperative symptoms. No previous study has compared the increases in SCA achieved by open-door laminoplasty (ODL) and double door laminoplasty (DDL) according to the preoperative lamina angle (LA). This study was designed to clarify the relationship between the laminoplasty opening angle (OA)/laminoplasty opening size (OS) and increases in the SCA following ODL and DDL according to the preoperative LA using a simulation model. Methods : The simulation model was constructed and validated by comparing the clinical data of 64 patients who had undergone C3-C6 laminoplasty (43 patients with ODL and 21 patients with DDL). SCA expansion was predicted with a verified simulation model at various preoperative LAs (from 28° to 32°) with different OAs (40° to 44°) and OSs (10 mm to 14 mm) recruited from patient data. Results : The constructed simulation model was validated by comparing clinical data and revealed a very high degree of correlation (r=0.935, p<0.001). In this validated model, at the same OA, the increase in SCA was higher following ODL than following DDL in the usual LA (p<0.05). At the same OS, the increase in SCA was slightly larger following DDL than following ODL, but the difference was not significant (p>0.05). The difference was significant when the preoperative LA was narrower or much wider. Conclusion : Based on clinical data, a simulation model was constructed and verified that could predict increases in the SCA following ODL and DDL. When applying this model, prediction in SCA increase using the OS parameter was more practical and compatible with clinical data. Both laminoplasties achieved enough SCA, and there was no significant difference between them in the usual range.