• Imaging Science in Dentistry
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• v.34 no.3
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• pp.165-169
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• 2004

Craniofacial dysostosis is considered to be one of rarely observed syndromes characterized by premature closing of all cranial sutures. The first patient was a 4-year-old male infant who had been complaining of empyema. Clinical findings showed exophthalmos, hypertelorism and facial asymmetry. Conventional radiographs demonstrated abscence of cranial sutures and underdeveloped maxilla. CT scan demonstrated the digital impressions of the inner surface of the cranial vault, enlarged and depressed sella turcica. The second patient was a 2-year-old female infant who had been complaining of facial deformity. Clinical findings showed hypertelorism and underdeveloped maxilla. Radiographs showed premature synostosis of all cranial sutures, depressed and enlarged sella turcica, and hypoplastic maxilla. 3 years after operation, her look improved. However, resurgery may be considered to decreasing intracranial pressure and for correction of facial deformity. Two interesting cases showing ‘cloverleaf’ skulls were presented.

• Imaging Science in Dentistry
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• v.33 no.2
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• pp.107-112
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• 2003

Purpose : To determine the relationship between clinical symptoms and magnetic resoncance (MR) images in patients presenting with temoporomandibular joint (TMJ) disorders. Materials and Methods: This study was based on 172 joints in 86 patients presenting with TMJ disorders. Joint pain and sound during jaw opening and closing movements were recorded, and the possible relationship between disc positions and bony changes of the condylar head and the articular fossa in MR images in the oblique sagittal planes were examined. Data were analyzed by Chi-square test. Results : There was no statistically significant relationship between clinical symptoms and MR images in the patients with TMJ disorders. Conclusion: In the patient with TMJ disorders, joint pain and sound could not be specific clinical symptoms that are related with MR image findings, and asymptomatic joints did not necessarily imply that the joints are normal according to MR image findings.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.3
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• pp.329-338
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• 2007

Purpose. The aim of this study is to evaluate the effect of TiN coating of abutment screw on the unscrewing torque. Material and methods. Titanium and Gold-Tite abutment screws were classified into two groups, Group A and C respectively, as control groups. Titanium abutment screws with TiN coatings were also classified into two groups, Group B and D, as experimental ones. Group A and B were tightened to 20 Ncm input torque, and Group C and D were tightened to 32 Ncm torque. Detorque values were measured with digital torque gauge during repeated closing and opening experiment. Results. Abutment screws with TiN coating (Group B and D) showed statistically significant higher mean detorque values than those of Group A and C. Discussion. Physical properties of TiN coating, such as low friction coefficient, high hardness and wear resistance, might contribute to higher detorque values. Conclusion. It is suggested that TiN coating of abutment screw help to reduce the risk of screw loosening and improve the stability of screw joint.

• Structural Engineering and Mechanics
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• v.33 no.6
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• pp.725-745
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• 2009

In this paper, probabilistic seismic performance assessment of a typical non-seismic RC frame building representative of a large inventory of existing buildings in developing countries is conducted. Nonlinear time-history analyses of the sample building are performed with 20 large-magnitude medium distance ground motions scaled to different levels of intensity represented by peak ground acceleration and 5% damped elastic spectral acceleration at the first mode period of the building. The hysteretic model used in the analyses accommodates stiffness degradation, ductility-based strength decay, hysteretic energy-based strength decay and pinching due to gap opening and closing. The maximum inter story drift ratios obtained from the time-history analyses are plotted against the ground motion intensities. A method is defined for obtaining the yielding and collapse capacity of the analyzed structure using these curves. The fragility curves for yielding and collapse damage levels are developed by statistically interpreting the results of the time-history analyses. Hazard-survival curves are generated by changing the horizontal axis of the fragility curves from ground motion intensities to their annual probability of exceedance using the log-log linear ground motion hazard model. The results express at a glance the probabilities of yielding and collapse against various levels of ground motion intensities.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.796-799
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• 2006

This paper presents a new method for automatic detection of skew in a document image using mathematical morphology. To speed up processing, we use reduced image but it still requires long time to estimate the skew angle so the proposed method works with region of interest, not with whole image. Character strings are connected by using morphological closing operation and a component labeling is used to select region of interest. The method considers the lowermost pixels of characters in candidate regions in the binary image of original document image. Experimental results shows that the proposed method is extremely fast and robust as well as independent of script forms.

• Journal of Oral Medicine and Pain
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• v.25 no.2
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• pp.215-221
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• 2000

A 69-year-old male pateint was admitted for discomfort on right temporomandibular joint during opening, closing and chewing that started few months ago. The patient had no special medical history except for lung tuberculosis approximately 30 years ago and nothing specific appeared on a physical exam taken 2 months ago. Clinical tests show that mouth opening of 53mm which was normal and no joint sound, deviation, pain during opening. But tenderness to palpation on Rt masseter muscle and pain existed on Rt temporomandibular joint during loading test on the right joint. No pain existed during resistance test and protrusion and range of lateral movement was normal. Rt temporomandibular joint was not swollen and no palpable mass was observed. No previous trauma history to the face existed. On X-ray calcific material existed in the joint cavity and on CT image, approximately 2mm sized calcific material appeared on the Rt temporomandibular joint but no change in bone appeared on the condyle nor the temporal bone. The patient was diagnosed as loose body, and the symptoms were relived after 2 physical therapies and is under regular check ups. The purpose of this case is to review disease that cause loose bodies.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.4
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• pp.857-861
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• 2021

The study aims to find the asymmetric effect in National Stock Exchange in which the Nifty50 is considered as proxy for NSE. A return can be stated as the change in value of a security over a certain time period. Volatility is the rate of change in security value. It is an arithmetical assessment of the dispersion of yields of security prices. Stock prices are extremely unpredictable and make the investment in equities risky. Predicting volatility and modeling are the most profuse areas to explore. The current study describes the association between two variables, namely, stock yields and volatility in equity market in India. The volatility is measured by employing asymmetric GARCH technique, i.e., the EGARCH (1,1) tool, which was used in building the study. The closing prices of Nifty on day-to-day basis were used for analysis from the period 2011 to 2020 with 2,478 observations in the study. The model arrests the lopsided volatility during the mentioned period. The outcome of asymmetric GARCH model revealed the subsistence of leverage effect in the index and confirms the impact of conditional variance as well. Furthermore, the EGARCH technique was evidenced to be apt in seizure of unsymmetrical volatility.

• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.1-11
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• 2021

Piping systems comprising pumps and valves are essential in the power plant, oil, and defense industry. Their purpose includes a stable supply of the working fluid or ensuring the target system's safe operation. However, piping system accidents due to leakage of toxic substances, explosions, and natural disasters are prevalent In addition, with the limited maintenance personnel, it becomes difficult to detect, isolate, and reconfigure the damage of the piping system and recover the unaffected area. An autonomous recovery piping system can play a vital role under such circumstances. The autonomous recovery algorithms for the piping system can be divided into low-pressure control algorithms, hydraulic resistance control algorithms, and flow inventory control algorithms. All three methods include autonomous opening/closing logic to isolate damaged areas and recovery the unaffected area of piping systems. However, because each algorithm has its strength and weakness, appropriate application considering the overall design, vital components, and operating conditions is crucial. In this regard, preliminary research on algorithm's working principle, its design procedures, and expected damage scenarios should be accomplished. This study examines the characteristics of algorithms, the design procedure, and working logic. Advantages and disadvantages are also analyzed through simulation results for a simplified piping system.

• Journal of Oral Medicine and Pain
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• v.46 no.4
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• pp.143-149
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• 2021

Purpose: Oromandibular dystonia is a neurological disorder that affects the jaw and lower face muscles, often resulting in abnormal repetitive movement of the jaw and perioral structures. The purpose of this study was to assess the effectiveness of surface electromyography (EMG) in evaluating the treatment outcome of oromandibular dystonia. Methods: Based on a retrospective review of medical records, we analyzed the data of four patients who received medication or botulinum toxin injection, as well as surface EMG of the jaw muscles before and after treatment. We assessed the patients' clinical characteristics and the results of surface EMG before and after treatment. Results: The case series included one female and three males, and the age range was 65-78 years. Based on the clinical features, two subjects were classified as jaw deviation and the remaining two were as jaw closing. Dystonic patterns revealed by surface EMG varied, including phasic, tonic, and mixed contraction patterns. EMG amplitude after treatment was lower than pre-treatment value in all four subjects, suggesting improved clinical signs and symptoms. One subject who received clonazepam and another who received botulinum toxin injection showed a remarkable reduction in EMG amplitude within a normal range. Conclusions: Surface EMG can be used to effective evaluate treatment outcomes in patients with oromandibular dystonia. It could be considered as an adjunctive diagnostic tool in managing patients with dystonia.

• The korean journal of orthodontics
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• v.31 no.3 s.86
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• pp.325-333
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• 2001

Optimal orthodontic treatment could be possible when a orthodontist can predict and control tooth movement by applying a planned force system to the dentition. The moment to force(M/F) ratio at the bracket, has been shown to be a primary determinate of the pattern of tooth movement. As various n/F ratios are applied to the bracket on the tooth crown, strain distribution in periodontium can be changed, and the center of rotation in tooth movement can be determined. It is, therefore, so important in clinicalorthodontics to know the strain distribution in a force system of a M/F ratio. The purpose of this study was to analyze the strain distribution in orthodontic force system by strain gauge attached to tooth root, and to evaluate the usage of the method. For this study, an experimental upper anterior arch model was constructed, where upper central incisors, on the root surface of which, 8 strain gauges were attached, were implanted In the photoelastic resin, as in the case of 4mm midline diastema. Three types of closing of upper midline diastema closure were compared : 1. with elastomeric chain(100g force) in no arch wire, 2. elastomeric chain in .016“ round steel wire, 3. elastomeric chain in .016”x.022“ rectangular steel wire. The results were as follows. 1. Strain distributions on labial, lingual, mesial and distal root surface of tooth were able to be evaluated with the strain gauge method, and the patterns of tooth rotation were understood by presuming the location of moment arm. 2. Extrusion and tipping movement of tooth was seen in closing in no arch wire, and intrusion and bodily movement was seen with steel arch wire inserted.