• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.429-432
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• 2015

Radio Frequency (RF) coils in Magnetic Resonance Imaging (MRI) systems interact with a patient's tissues, resulting in the absorption of RF energy by the tissues. The presence of an electrically conducting medical implant may concentrate the RF energy and causes tissue heating near the implant devices. Here we present a novel design for a medical lead to reduce this undesired heating. Specific Absorption Rate (SAR), an indicator of heating, was calculated. Remcom XFdtd software was used to calculate the peak SAR distribution (1g and 10 g) in a realistic model of the human body. The model contained a medical lead that was exposed to RF magnetic fields at 64 MHz (1.5 T MRI), 128 MHz (3 T MRI) and 300 MHz (7 T MRI) using a model of an MR birdcage body coil. Our results demonstrate that, our proposed design of adding nails to the medical lead can significantly reduce the SAR for different MRI systems.

• Imaging Science in Dentistry
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• v.32 no.1
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• pp.27-33
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• 2002

Purpose: To evaluate the influence of threshold value of computed tomography on the accuracy of rapid prototyping (RP) medical model Material and Methods : CT datas of a human dry skull were transferred from CT scanner via compact disk to a personal computer (PC). 3-dimensional image reconstruction on PC by V-works/sup TM/ 3.0 (CyberMed. Inc.) software and RP models fabrication were followed. 2-RP models were produced by threshold value of 500 and 800 selected in surface rendering process. Linear measurements between arbitrary 12 anatomical landmarks on dry skull, 3-D image model, and 2-RP models were done and compared. Thus, the accuracy of 500 RP and 800RP models was respectively evaluated. Results: There was mean difference (% difference) in absolute value of 2.27 mm (2.73%) between linear measurements of dry skull and 500 RP model. There was mean difference (% difference) in absolute value of 1.94 mm (2.52%) between linear measurements of dry skull and 800 RP model. Conclusion: Slight difference of threshold value in rendering process of 3-D modelling made a influence on the accuracy of RP medical model.

• Korea Journal of Hospital Management
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• v.16 no.3
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• pp.41-56
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• 2011

The research was to investigate the effect of quality cognition of the web site of the facility and relationship commitment on customer loyalty. The respondents were 190 patients and caregivers. Data were collected from March 1st to 31st, 2010 at C university hospital in G city. The effect of facility web site of quality cognition and relationship commitment on customer loyalty showed 43.9%(F=35.806) in model 1, 58.4%(F=51.113) in model 2, and 58.7%(F=28.185) in model 3. Also, medical information & usage, aesthetics was significance in model 1, medical information & usage, relationship commitment in model 2. In relationship between web site quality cognition and customer loyalty, moderate effect of relationship commitment were not considerable in model 3. As a result, customer loyalty is the leading fact for quality cognition of the web site more than relationship commitment. Therefore, customer loyalty leaves its possibility of increment when facility web site is designated depending on medical information and aesthetics.

• Communications for Statistical Applications and Methods
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• v.30 no.3
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• pp.291-309
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• 2023

Longitudinal count data has been widely collected in biomedical research, public health, and clinical trials. These repeated measurements over time on the same subjects need to account for an appropriate dependency. The Poisson regression model is the first choice to model the expected count of interest, however, this may not be an appropriate when data exhibit over-dispersion or under-dispersion. Recently, Conway-Maxwell-Poisson (CMP) distribution is popularly used as the distribution offers a flexibility to capture a wide range of dispersion in the data. In this article, we propose a Bayesian CMP regression model to accommodate over and under-dispersion in modeling longitudinal count data. Specifically, we develop a regression model with random intercept and slope to capture subject heterogeneity and estimate covariate effects to be different across subjects. We implement a Bayesian computation via Hamiltonian MCMC (HMCMC) algorithm for posterior sampling. We then compute Bayesian model assessment measures for model comparison. Simulation studies are conducted to assess the accuracy and effectiveness of our methodology. The usefulness of the proposed methodology is demonstrated by a well-known example of epilepsy data.

• Korean Medical Education Review
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• v.9 no.2
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• pp.29-40
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• 2007

Purpose: This study analysed the intention of medical students career choice, educational programmes, and mentoring and counseling system for career planning at Yonsei medical school in Korea. Methods: The data were collected based on four separate graduation questionnaires at Yonsei medical school in the years of 2005, 2006, 2007, and 2008. The number of the survey was 130 in 2005, 130 in 2006, 153 in 2007, and that of the latest was 120 in 2008. We analysed the career intention on medical specialties and activities, and perceptions of important factors in choosing medical specialty. Results : The results which can be drawn from this study are these: firstly. students had more intention for choosing clinical medicine as university faculty than any other activities. While male students preferred to major in surgery, neurosurgery, orthopedic surgery, urology, otorhinolaryngology, female students in internal medicine, neurology, anesthesiology and pain medicine, diagnostic radiology, laboratory medicine. Secondly, students perceived that the most important factor which can influence on choosing a medical specialty was individual factor such as one's interests and concerns, values, and aptitudes. In stead, they relatively less perceived mentor and role model's effects on choosing a medical specialty compared to those of the United States of America. Third, the career planning at Yonsei medical school was evaluated well, especially educational programmes for career planning such as self assessment programme, elective(specialized) courses, and conversation with a senior programme. Conclusions: Unexpectedly, there are high demands for career planning by medical students. Therefore, we will reorganize systematic devices for career planning such as mentoring and counseling system at medical school.

• Journal of Biomedical Engineering Research
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• v.43 no.6
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• pp.382-389
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• 2022

In this study, the accuracy of the orthognathic surgical guides with single-stage split path was upgraded to realize orthognathic surgical guides with two-stage split path and simulated surgery was performed to verify its accuracy. As a result, the average error distance between the simulation model and the scan model was + 0.289 / - 0.468 mm (standard deviation 0.128), which was confirmed to be within ± 0.5 mm, which is a clinically acceptable level. Also, there was no significant difference compared with the average value of + 0.313 / - 0.456 mm (average standard deviation 0.106) of the conventional single-stage split path type device. It is judged that the use of this device can contribute to the reduction of surgical time and increase in accuracy since a separate finishing operation for bone preparation is unnecessary.

• Korean Circulation Journal
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• v.53 no.11
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• pp.758-771
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• 2023

Background and Objectives: Paroxysmal atrial fibrillation (AF) is a major potential cause of embolic stroke of undetermined source (ESUS). However, identifying AF remains challenging because it occurs sporadically. Deep learning could be used to identify hidden AF based on the sinus rhythm (SR) electrocardiogram (ECG). We combined known AF risk factors and developed a deep learning algorithm (DLA) for predicting AF to optimize diagnostic performance in ESUS patients. Methods: A DLA was developed to identify AF using SR 12-lead ECG with the database consisting of AF patients and non-AF patients. The accuracy of the DLA was validated in 221 ESUS patients who underwent insertable cardiac monitor (ICM) insertion to identify AF. Results: A total of 44,085 ECGs from 12,666 patient were used for developing the DLA. The internal validation of the DLA revealed 0.862 (95% confidence interval, 0.850-0.873) area under the curve (AUC) in the receiver operating curve analysis. In external validation data from 221 ESUS patients, the diagnostic accuracy of DLA and AUC were 0.811 and 0.827, respectively, and DLA outperformed conventional predictive models, including CHARGE-AF, C2HEST, and HATCH. The combined model, comprising atrial ectopic burden, left atrial diameter and the DLA, showed excellent performance in AF prediction with AUC of 0.906. Conclusions: The DLA accurately identified paroxysmal AF using 12-lead SR ECG in patients with ESUS and outperformed the conventional models. The DLA model along with the traditional AF risk factors could be a useful tool to identify paroxysmal AF in ESUS patients.

• Parasites, Hosts and Diseases
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• v.60 no.4
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• pp.241-246
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• 2022

Felids are the unique definitive host of Toxoplasma gondii. The intestine of felid is the only site for initiating Toxoplasma gondii sexual reproduction. T. gondii excretes millions of infectious oocysts from the intestine, which are the primary source of infection. There are many difficulties in developing vaccines and drugs to control oocyst excretion due to the lack of an appropriate experimental model. Here, we established an in vitro feline intestinal epithelial cell (IEC) infection system and an efficient animal model of T. gondii Chinese 1 genotype, Wh6 strain (TgCtwh6). The Kunming mice brain tissues containing TgCtwh6 cysts were harvested 42-day post-infection. The bradyzoites were co-cultured with cat IECs in vitro at a ratio of 1:10. Five 3-month-old domestic cats were orally inoculated with 600 cysts each. The oocysts were detected by daily observation of cat feces by microscopy and polymerase chain reaction. We found that the parasite adhered and invaded cat IECs in vitro, transformed into tachyzoites, and then divided to form rose-like structures. These parasites eventually destroyed host cells, escaped, and finished the asexual reproduction process. Schizonts associated with sexual reproduction have not been observed during development in vitro cultured cells. However, schizonts were detected in all infected cat intestinal epithelial cells, and oocysts were presented in all cat feces. Our study provides a feasible cell model and an efficient infection system for the following studies of T. gondii sexual reproduction, and also lays a foundation to develop drugs and vaccines for blocking excretion and transmission of oocysts.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1192-1197
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• 2013

In this paper Ubiquitous Medical Electronic Device Export was defined, and it's job analysis. The authors have been defined the job and classified duties and tasks of Ubiquitous Medical Electronic Device Export. To fine what is the most efficient task for Ubiquitous Medical Electronic Device Export, we have been investigated the levels of importance, difficulty, frequency and entry in each task. A DACUM committee is composed of total 12 members, which are one facilitator, 10 panel members, one coordinator & recorder to analyze the job of Ubiquitous Medical Electronic Device Export. Following is the result of this study. First, The process began with the identification of a job title and definition of Ubiquitous Medical Electronic Device Export. Second, a job model of Ubiquitous Medical Electronic Device Export is constructed based on the results of DACUM job analysis. 5 duties and 33 tasks are analyzed. Third, occupational specification was drawn up in consultation with SME council. Fourth, duty specification was drawn up in consultation. 33 tasks that are essential in entry level of occupation are identified. Fifth, task specification was drawn up in consultation. Detail task component which include skill, materials, knowledge, equipment, achievement level and tool was specified in task specification.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.216-218
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• 2002

Fluence and LET spectrum for 290,400 MeV/u $\^$12/C and 400 MeV/u $\^$20/Ne beams have been measured by a $\Delta$E-E counter telescope. Total charge-changing cross sections are deduced from measured fluence. The measured cross sections agree with previous measurements, however, they are disagreement with a model calculation. To dose-averaged LETs, the model calculation can reproduce the measured LETs except for peak LETs at Bragg peak region.