• KIEE International Transactions on Electrophysics and Applications
• /
• v.11C no.2
• /
• pp.6-11
• /
• 2001

Abstract- In this paper, a new Partial Discharge (PD) detection using Pockels cell was proposed and considerable apparent chaotic characteristics were discussed. For this purpose, PD was generated from needle-plane electrode in air and detecte by optical measuring system using Pockels cell, based on Mach-Zehner interferometer, consisting of He-Ne laser, single mode optical fiber, 50/50 beam splitter and photo detector. In addition, the presence of chaos of the PD signals has been investigated by examining their means of qualitative and quantitative information. For the former, return map and 3-dimensional strange attractor have been drawn in order to investigate the presence of chaotic characteristics relevant to PD signals, detected through CT and Peckels sensor respectively, in the normalized time series. The presence of strange attractor indicates the existence of fractal structures in it's phase space. For the latter, several dimension values of strange attractor were verified sequentially. Throughout this paper, it is likely that the chaotic characteristics regarding the PD signals under air are verified.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.8
• /
• pp.1235-1240
• /
• 2005

A combination of electrospray ionization and tandem mass spectrometry was used to characterize the scavenging reactions of acrylamide (AA) in the presence of glutathione (GSH) in vitro. In the presence of GSH, AA was deactivated effectively and scavenged by reactions consuming small amount of GSH. Reaction products and structural information were identified using collision-induced dissociation (CID) in an ion trap mass spectrometer. In the mixture of GSH and AA, significant increase in abundance of fragment ion peak was observed at m/z 233, which was identified as $[Cys-Glu]^+$, formed by the elimination of glycine moiety of GSH. GSH also contributes to the AA scavenging reaction by conjugating with AA through the sulfhydryl group in cysteine moiety. The probable scavenging reaction pathway of AA in the presence of GSH has been proposed based on the CID experimental data.

• Journal of Applied Reliability
• /
• v.16 no.1
• /
• pp.56-63
• /
• 2016

Purpose: The purpose of this study is to point out that the Kaplan-Meier method is not valid to calculate the survival probability or failure probability (risk) in the presence of competing risks and to introduce more valid method of cumulative incidence function. Methods: Survival analysis methods have been widely used in biostatistics division. However the same methods have not been utilized in reliability division. Especially competing risks cases, where several causes of failure occur and the occurrence of one event precludes the occurrence of the other events, are scattered in reliability field. But they are not noticed in the realm of reliability expertism or they are analysed in the wrong way. Specifically Kaplan-Meier method which assumes that the censoring times and failure times are independent is used to calculate the probability of failure in the presence of competing risks, thereby overestimating the real probability of failure. Hence, cumulative incidence function is introduced and sample competing risks data are analysed using cumulative incidence function and some graphs. Finally comparison of cumulative incidence functions and regression type analysis are mentioned briefly. Results: Cumulative incidence function is used to calculate the survival probability or failure probability (risk) in the presence of competing risks and some useful graphs depicting the failure trend over the lifetime are introduced. Conclusion: This paper shows that Kaplan-Meier method is not appropriate for the evaluation of survival or failure over the course of lifetime. In stead, cumulative incidence function is shown to be useful. Some graphs using the cumulative incidence functions are also shown to be informative.

• Smart Structures and Systems
• /
• v.11 no.4
• /
• pp.349-364
• /
• 2013

Recently, researchers in the field of structural health monitoring (SHM) have been rigorously striving to replace the conventional NDE techniques with the smart material based SHM techniques, employing smart materials such as piezoelectric materials. For instance, the electromechanical impedance (EMI) technique employing piezo-impedance (lead zirconate titanate, PZT) transducer is known for its sensitivity in detecting local damage. For practical applications, various external factors such as fluctuations of temperature and loading, affecting the effectiveness of the EMI technique ought to be understood and compensated. This paper aims at investigating the damage monitoring capability of EMI technique in the presence of axial stress with fixed boundary condition. A compensation technique using effective frequency shift (EFS) by cross-correlation analysis was incorporated to compensate the effect of loading and boundary stiffening. Experimental tests were conducted by inducing damages on lab-sized aluminium beams in the presence of tensile and compressive forces. Two types of damages, crack propagation and bolts loosening were simulated. With EFS for compensation, both cross-correlation coefficient (CC) index and reduction in peak frequency were found to be efficient in characterizing damages in the presence of varying axial loading.

• Communications for Statistical Applications and Methods
• /
• v.25 no.1
• /
• pp.43-60
• /
• 2018

This paper considers the use of classical and Bayesian inference methods to analyze data generated by variables whose natural behavior can be modeled using asymmetric distributions in the presence of left censoring. Our approach used a $L{\grave{e}}vy$ distribution in the presence of left censored data and covariates. This distribution could be a good alternative to model data with asymmetric behavior in many applications as lifetime data for instance, especially in engineering applications and health research, when some observations are large in comparison to other ones and standard distributions commonly used to model asymmetry data like the exponential, Weibull or log-logistic are not appropriate to be fitted by the data. Inferences for the parameters of the proposed model under a classical inference approach are obtained using a maximum likelihood estimators (MLEs) approach and usual asymptotical normality for MLEs based on the Fisher information measure. Under a Bayesian approach, the posterior summaries of interest are obtained using standard Markov chain Monte Carlo simulation methods and available software like SAS. A numerical illustration is presented considering data of thyroglobulin levels present in a group of individuals with differentiated cancer of thyroid.

• Journal of Korean society of Dental Hygiene
• /
• v.21 no.5
• /
• pp.611-620
• /
• 2021

Objectives: This study investigated health behavior and nutritional status according to the presence or absence of periodontal disease using data from the Sixth National Health Nutrition Survey. Methods: Data from the 2013-2015 National Health Nutrition Survey were analyzed by frequency analysis, chi-square test, and Pearson's correlation analysis using SPSS 21.0. Results: Periodontal disease was more frequent in the group of patients who perceived that their subjective health status was "very bad" or were underweight according to the BMI classification. In men, periodontal disease occurred more frequently in those who were taking calcium (p<0.05), and periodontal disease occurred more frequently in the age group of 20-39, regardless of sex (p<0.05). In women, periodontal disease was less frequent in the group taking vitamin A. In both men and women, the presence of periodontal disease correlated with high fasting blood sugar and glycated hemoglobin levels. Conclusions: A customized program should be developed for each patient to identify factors that affect the relationship among periodontal disease, nutrient intake, and blood parameters. Such information will help improve the oral health of the population.

• International journal of advanced smart convergence
• /
• v.11 no.3
• /
• pp.93-101
• /
• 2022

Immersion is a features of VR technology, and the most important condition for evaluating VR experience. With the improvement of VR technology, including the presentation accuracy of VR content, the degree of interaction is diversified, the user's immersion in VR equipment should not only be improved technically, but researched from the user's perception level. The paper defines two important factors, immersion and presence, in a participant's experience with a VR device. Although the current technology can already simulate the real environment information visually and audibly, the content of the VR environment is not enough for us to achieve a completely real experience. Based on the Flow theory of Csikszentmihalyi and the sensory immersion achieved by current technology, this paper proposes the key factors of how to achieve conscious immersion for users in VR media. We prove that immersion is an indicator of the true degree of sensory simulation of VR equipment and is the basis for the realization of flow experience. What really makes the participant feel a perfect experience is the content provided by the VR environment and gave participants a sense of presence, it is not limited to video or games. On the premise of the Multi-Sensory, Immersion, Interactivity and Imagination experience achieved by using virtual reality technology, combined with the content creation of flow theory, the interactive immersion achieved by users is an important method to realize the awareness immersion of VR equipment.

• The korean journal of orthodontics
• /
• v.54 no.4
• /
• pp.239-246
• /
• 2024

Objective: To examine the areas of the maxillary tuberosity (MT) (coronal, apical, width, and height) with respect to the presence or absence of the third molar to establish possible anatomical limitations for molar distalization. Methods: A total of 277 tuberosities were evaluated through sagittal computed tomography (CT) images, divided for measurement into coronal (free of bone), apical (area of influence of the maxillary sinus), and tuberosity (bony area) zones, and stratified by the presence or absence of the third molar, sex, and two age subgroups. Mann-Whitney U test was used to compare the groups considering the third molar. Results: The medians of the width and height of the tuberosity decreased significantly in the absence of the third molar (P < 0.001). The apical area also showed differences, with negative values in the absence of the third molar and positive values in the presence of the third molar (P < 0.001). However, no differences were observed for the coronal area (P > 0.05). Conclusions: In the absence of the third molar, the size of the MT, represented by its width and height, was smaller and negative values (decrease) were observed for the maxillary sinus. The sagittal CT provides useful information regarding the amount of bone tissue available for distalization and relationship of the second molar with respect to the maxillary sinus, which allows individualizing each case in relation to the amount and type of movement expected.

• International Journal of Computer Science & Network Security
• /
• v.23 no.2
• /
• pp.147-151
• /
• 2023

The article reviews the quality of information on the Internet in general and health information in particular, where the accumulation and steady increase of information available on the Internet, without concern for its quality or importance, and regardless of the target audience, in addition to the lack of evidence of its credibility such as the availability of the name of the editor and references, and the availability of the name of an academic or research body responsible for that information. Add to this the lack of bibliographic data that can help infer the novelty of the information, and verify the element of trust in it . The problem is exacerbated with regard to the health information available on the Internet, due to its danger resulting from the presence of false health information that may cause danger to human health if relied upon. Through this article, the researcher proposes criteria that can help users search for information to measure the degree of quality, trust, and credibility of information in general and health information available on the Internet in particular.

• The Journal of Society for e-Business Studies
• /
• v.18 no.1
• /
• pp.191-211
• /
• 2013

The deployment of social network service(SNS) makes the social network game(SNG) as the new value added service of SNS be popular. But, a few study had identified the reason of this popularity and the elements of SNG. Based on the social presence theory and media richness theory, we had tried to identify three community artifacts (i.e. persistent labeling, self presentation and deep profiling) and two media characteristics(i.e. vividness and interactivity) as the SNG elements in this research. Then we had empirically validated the effect of these elements on the SNGexperience (i.e. social presence, perceived enjoyment) and behavioral intentions (i.e. Continuous usage intention, willingness to pay and loyalty) of the users. We conducted a survey to the actual SNG users. 243 data were collected and analyzed by PLS algorism. The results indicated that the community artifacts mediated by the social presence and media characteristics could significantly affect on the experiences and behavioral intentions. These findings could contribute to identify what element could be the reason of social network game popularity and could also contribute to design more attractive social network game in practice.