• Imaging Science in Dentistry
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• v.51 no.3
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• pp.291-297
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• 2021

Purpose: This study was performed to evaluate the prevalence, distribution, and radiological features (as per the Shear classification) of dentigerous cysts in a Lebanese sample. Materials and Methods: It was an epidemiological, cross-sectional, 5-year retrospective study of 137 dentigerous cysts treated at Lebanese Army Dental Departments. The collected data comprised demographic and radiological information corresponding to patients from July 2015 to July 2020. Syndromic cases were excluded. Demographic data and the radiological features of cases were studied and analyzed. Results: Dentigerous cysts were treated in 109 patients (58.7% males and 41.3% females; mean age: 28.3±16.3 years) out of 6,013 patients(52% males and 48% females), with a prevalence of 1.8%. Dentigerous cysts were more commonly found in patients in their second and third decades of life than in older age groups. Of the 109 patients, 22.9% had multiple dentigerous cysts. Of the 137 cysts, 71.5% were mandibular. The most prevalent anatomical location was the posterior mandible, followed by the posterior maxilla. The most commonly involved tooth was the mandibular third molar. Regarding radiological types, the central type was the most common (60.6%), followed by the lateral type (29.2%), and the circumferential type (10.2%). Conclusion: The results of this study were similar to studies of other populations in terms of distribution and features. Multiple non-syndromic dentigerous cysts were more common than reported in other studies, which warrants further clinical studies to reveal previously undetected factors.

• Structural Engineering and Mechanics
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• v.81 no.1
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• pp.103-115
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• 2022

The prediction error variances for frequencies are usually considered as unknown in the Bayesian system identification process. However, the error variances for mode shapes are taken as known to reduce the dimension of an identification problem. The present study attempts to explore the effectiveness of Bayesian approach of model parameters updating using Markov Chain Monte Carlo (MCMC) technique considering the prediction error variances for both the frequencies and mode shapes. To remove the ergodicity of Markov Chain, the posterior distribution is obtained by Gaussian Random walk over the proposal distribution. The prior distributions of prediction error variances of modal evidences are implemented through inverse gamma distribution to assess the effectiveness of estimation of posterior values of model parameters. The issue of incomplete data that makes the problem ill-conditioned and the associated singularity problem is prudently dealt in by adopting a regularization technique. The proposed approach is demonstrated numerically by considering an eight-storey frame model with both complete and incomplete modal data sets. Further, to study the effectiveness of the proposed approach, a comparative study with regard to accuracy and computational efficacy of the proposed approach is made with the Sequential Monte Carlo approach of model parameter updating.

• Physical Therapy Korea
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• v.23 no.4
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• pp.27-37
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• 2016

Background: In previous studies regarding flexible pes planus, Foot orthosis, special shoes have been used as interventions for correcting malalignment and intrinsic muscles strengthening exercise have been regarded as interventions for foot function and supporting medial longitudinal arch during walking. However, some recent studies reported that strengthening extrinsic muscles as well as intrinsic muscles is more effective and active intervention for flexible pes planus. In particular, the tibialis posterior muscle of foot extrinsic muscles plays essential roles in maintaining the medial longitudinal arch during dynamic weight bearing and balance. In addition this muscle acts longer than other supination muscles during the stance phase in the gait cycle. Objects: This study aimed to investigate the effect of foot intrinsic muscle and tibialis posterior muscle strengthening exercise for plantar pressure and dynamic balance in adults with flexible pes planus. Methods: 16 young flexible pes planus adults (7 males, 9 females) were recruited and were randomized into two groups. The experimental group performed foot intrinsic muscle and tibialis posterior muscle strengthening training, the control group performed only foot intrinsic muscle strengthening training. All groups received strengthening training for 30 minutes five times a week for six weeks. Results: The experimental group had significantly lower plantar pressure of medial heel area than the control group in stand (p<.05). The experimental group had significantly higher dynamic balance ability than control group (p<.05). Conclusion: The results of this study provide evidence to suggest that foot intrinsic muscle and tibialis posterior muscle of extrinsic muscle strengthening exercises may improve plantar pressure distribution and dynamic balance ability in adults with flexible pes planus.

• Progress in Medical Physics
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• v.20 no.3
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• pp.152-158
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• 2009

Total Skin Electron Beam Therapy (TSEBT) of linear accelerator has become use so as to be useful, 2~9 MeV of energy territories came to be used with mycosis fungoides and cutaneous lymphomas in the superficial lesion treatment which covers the major portion of the body. I treat a patient to Stanford technique in this study, and it is $60^{\circ}$ around the patients whom Stanford technique irradiated electronic beam to a linear accelerator in horizontal directions and there is a way a standard of TSEBT treat it to six located field (anterior, posterior, and four obliques) becoming. An each field does horizontally it and consist to beam of the two component which fitted the center to a suitable angle. a patient treats it to three dual field a day in order to make short treatment time. when a first day, we treat one dual field at anterior position and two dual field at posterior position. when the second day, treat one dual field at posterior position and two dual field at anterior position. Therefore, six dual field is finished in perfect periodic two days. we made cylindrical acrylic phantom, and I inserted a dosimeter film between phantom. in order to measure a dose distribution calculation before treat a patient, and a patient checked it in six field directions that got from a treatment. It is after that thermoluminescent dosimetry (TLD) as it uses Rando phantom and then measurement dose distribution in six field directions after attaching at chest, the right and left flank, a back after irradiation.

• Magazine of the Korea Concrete Institute
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• v.11 no.2
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• pp.241-249
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• 1999

To estimate the compressive strength of concrete more realistically, relative large number of data are necessary. However, it is very common in practice that only limited data are available. The purpose of the present paper is therefore to propose a realistic method to estimate the compressive strength of concrete with limited data in actual site. The Bayesian method of statistical analysis has been applied to the problem of the estimation of compressive strength of concrete. The mean compressive strength is considered as the random parameter and a prior distribution is selected to enable updating of the Bayesian distribution of compressive strength of concrete reflecting both existing data and sampling observations. The updating of the Bayesian distribution with increasing data is illustrated in numerical application. It is shown that by combining prior estimation with information from site observation, more precise estimation is possible with relatively small sampling. It is also seen that the contribution of the prior in determining the posterior distribution depends on its sharpness or flatness in relation to the sharpness or flatness of the likelihood function. The present paper allows more realistic determination of concrete strength in site with limited data.

• Communications for Statistical Applications and Methods
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• v.24 no.3
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• pp.193-209
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• 2017

The power Lindley distribution with some of its properties is considered in this article. Maximum likelihood, least squares, maximum product spacings, and Bayes estimators are proposed to estimate all the unknown parameters of the power Lindley distribution. Lindley's approximation and Markov chain Monte Carlo techniques are utilized for Bayesian calculations since posterior distribution cannot be reduced to standard distribution. The performances of the proposed estimators are compared based on simulated samples. The waiting times of research articles to be accepted in statistical journals are fitted to the power Lindley distribution with other competing distributions. Chi-square statistic, Kolmogorov-Smirnov statistic, Akaike information criterion and Bayesian information criterion are used to access goodness-of-fit. It was found that the power Lindley distribution gives a better fit for the data than other distributions.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.98-105
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• 2012

This paper describes the Bayesian approach for reliability demonstration test based on the samples from a finite population. The Bayesian approach involves the technical method about how to combine the prior distribution and the likelihood function to produce the posterior distribution. In this paper, the hypergeometric distribution is adopted as a likelihood function for a finite population. The conjugacy of the beta-binomial distribution and the hypergeometric distribution is shown and is used to make a decision about whether to accept or reject the finite population judging from a viewpoint of faulty goods. A numerical example is also given.

• Journal of the Korean Data and Information Science Society
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• v.27 no.4
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• pp.1091-1100
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• 2016

This paper considers the noninformative priors for the linear function of parameters in the lognormal distribution. The lognormal distribution is applied in the various areas, such as occupational health research, environmental science, monetary units, etc. The linear function of parameters in the lognormal distribution includes the expectation, median and mode of the lognormal distribution. Thus we derive the probability matching priors and the reference priors for the linear function of parameters. Then we reveal that the derived reference priors do not satisfy a first order matching criterion. Under the general priors including the derived noninformative priors, we check the proper condition of the posterior distribution. Some numerical study under the developed priors is performed and real examples are illustrated.

• Journal of Integrative Natural Science
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• v.7 no.2
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• pp.138-144
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• 2014

Fisher information matrix plays an important role in statistical inference of unknown parameters. Especially, it is used in objective Bayesian inference where we calculate the posterior distribution using a noninformative prior distribution, and also in an example of metric functions in geometry. To estimate parameters in a distribution, we can use the Fisher information matrix. The more the number of parameters increases, the more its matrix form gets complicated. In this paper, by using Mathematica programs we derive the Fisher information matrix for 4-parameter generalized gamma distribution which is used in reliability theory.

• Physical Therapy Korea
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• v.3 no.2
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• pp.55-76
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• 1996

The objective of this study was to identify the immediate effects of the short leg brace on the weight bearing distribution and gait patterns of hemiplegic patients. The subjects of this study were 18 hemiplegic patients who had been hospitalized or visited out-patient department of Rehabilitation Hospital, Yonsei University College of Medicine, from January 5, 1996 through March 23, 1996. PLS(Posterior Leaf Spring) on and off changes in gait patterns were measured using ink foot print as well as by recording weight bearing distribution using a limb load monitor. The data were analyzed by the correlation and paired t-test. The findings were as follows: 1. Eighteen subjects were more weighted on the affected leg when PLS was put off(42.74%) than on(40.08%). 2. The defference in gait patterns between PLS on and off was statistically significant, with an increase in step length by 1.7cm on the involved side; a decrease in foot angle by 4.41 degree on the involved side; and a narrowing of base of support by 1.46cm when PLS were off. In conclusion, this study showed that PLS did not affect the weight bearing distribution and gait patterns of hemiplegic patients. Since, the evaluation method used in this study has limitations in regard to temporal distance gait values. Further studies are required to numerous experiments for subject and extensive study.