• The Korean Journal of Applied Statistics
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• v.34 no.6
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• pp.863-874
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• 2021

In this paper, we propose a post-selection inference procedure for the fused lasso signal approximator (FLSA). The FLSA finds underlying sparse piecewise constant mean structure by applying total variation (TV) semi-norm as a penalty term. However, it is widely known that this convex relaxation can cause asymptotic inconsistency in change points detection. As a result, there can remain false change points even though we try to find the best subset of change points via a tuning procedure. To remove these false change points, we propose a post-selection inference for the FLSA. The proposed procedure applies a permutation test based on CUSUM statistic. Our post-selection inference procedure is an extension of the permutation test of Antoch and Hušková (2001) which deals with single change point problems, to multiple change points detection problems in combination with the FLSA. Numerical study results show that the proposed procedure is better than naïve z-tests and tests based on the limiting distribution of CUSUM statistics.

• Korean Journal of Applied Biomechanics
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• v.31 no.2
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• pp.104-112
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• 2021

Objective: This study aimed to analyze the effects of consecutive whole body vibration through heel raise posture on the center of pressure and electromyography of anterior tibial muscle, lateral gastrocnemius and soleus muscles during single-leg stance. Method: The subjects of this study included 30 healthy males in their 20's, with the following inclusion criteria: no history of orthopaedic medical history, no participation in regular exercises, no history of whole body vibration exercise, and right leg being the dominant leg. The experimental procedure involved pretreatment measurement of eye open single-leg stance, application of whole body vibration for 30 seconds, post-treatment measurement (3 measurements in total). Static and dynamic movements have been measured over 2 separate experiments, with 72 hours gap between the experiments. Static movement involved maintaining single-leg heel raise posture for 30 seconds while applying whole body vibration, and dynamic movement involved heel raise (15 repetitions over 30 seconds) while applying whole body vibration. The strength of applied whole body vibration was 35 Hz frequency and 2~4 mm amplitude. Results: As the single-leg posture after static heel raise posture, mediolateral velocity of the center of pressure at post 2 and post 3 were significantly reduced compared to the pre-treatment measurement. In addition, the percentage for reference voluntary contraction in anterior tibial muscle and soleus and median frequency at anterior tibial muscle and lateral gastrocnemius muscle at post 3 were significantly decreased compared to the pre-treatment value. As the single-leg posture after dynamic heel raise posture, the mediolateral 95% edge frequency of the center of pressure and median frequency at anterior tibial muscle, lateral gastrocnemius muscle, and soleus muscle at post 3 were significantly reduced compared to the pre-treatment value. Conclusion: Acute whole body vibration via static and dynamic heel raise posture have positive effect on mediolateral posture control during single-leg stance.

• Advances in nano research
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• v.16 no.6
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• pp.623-638
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• 2024

This study investigates the thermal post-buckling behavior of concrete eccentric annular sector plates reinforced with graphene oxide powders (GOPs). Employing the minimum total potential energy principle, the plates' stability and response under thermal loads are analyzed. The Haber-Schaim foundation model is utilized to account for the support conditions, while the transform differential quadrature method (TDQM) is applied to solve the governing differential equations efficiently. The integration of GOPs significantly enhances the mechanical properties and stability of the plates, making them suitable for advanced engineering applications. Numerical results demonstrate the critical thermal loads and post-buckling paths, providing valuable insights into the design and optimization of such reinforced structures. This study presents a machine learning algorithm designed to predict complex engineering phenomena using datasets derived from presented mathematical modeling. By leveraging advanced data analytics and machine learning techniques, the algorithm effectively captures and learns intricate patterns from the mathematical models, providing accurate and efficient predictions. The methodology involves generating comprehensive datasets from mathematical simulations, which are then used to train the machine learning model. The trained model is capable of predicting various engineering outcomes, such as stress, strain, and thermal responses, with high precision. This approach significantly reduces the computational time and resources required for traditional simulations, enabling rapid and reliable analysis. This comprehensive approach offers a robust framework for predicting the thermal post-buckling behavior of reinforced concrete plates, contributing to the development of resilient and efficient structural components in civil engineering.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4593-4595
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• 2012

Introduction: Mobile learning enables users to interact with educational resources while in variable locations. Medical students in residency positions need to assimilate considerable knowledge besides their practical training and we therefore aimed to evaluate the impact of using short message service via cell phone as a learning tool in residents of Obstetrics and Gynecology in our hospital. Methods: We sent short messages including data about breast cancer to the cell phones of 25 residents of gynecology and obstetrics and asked them to study a well-designed booklet containing another set of information about the disease in the same period. The rate of learning derived from the two methods was compared by pre- and post-tests and self-satisfaction assessed by a relevant questionnaire at the end of the program. Results: The mobile learning method had a significantly better effect on learning and created more interest in the subject. Conclusion: Learning via receiving SMS can be an effective and appealing method of knowledge acquisition in higher levels of education.

• Journal of Chest Surgery
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• v.18 no.2
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• pp.293-298
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• 1985

Cor triatriatum is a rare congenital malformation of the heart in which a septum stretches in a transverse plane through the left atrium, thus creates two left atrial subchambers. The upper one connects with the pulmonary veins, and the lower connects with the left ventricles. Due to the rarity of, and difficulty in diagnosing car triatriatum, data on the surgery of the disease are of necessity and very limited. A case of cor triatriatum combined with atrial septal defect and persistent left superior vena cava was experienced in November, 1984 in Chonnam University Medical School. There was a transverse septum in the left atrium below atrial septal defect, all pulmonary veins were drained into the upper chamber of the left atrium which connected with the right atrium via atrial septal defect and the lower chamber via an oval opening[8mm] in the abnormal septum and the lower chamber was connected with the left atrial appendage, and the left ventricle via mitral valve. There was persistent left superior vena cava drained to left atrium and coronary sinus. The abnormal transverse septum within the left atrium was completely excised and the atrial septal defect was repaired with Woven Dacron patch. The post-operative course was not eventful and the patient was discharged to home with good result on the 15th postoperative day, and has been in good condition upto now.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.147-148
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• 2007

In this study, the technology to grow oriented nanotube thin film from dip-coated $TiO_2$ using hydrothermal method has been successfully developed. The effects of preparation parameters, such as reaction temperature, duration and post treatment conditions on the film morphologies and the adherence to the substrate, have been examined. A general formation mechanism of oriented titanate nanotube thin film is proposed in terms of the detailed observation of the products via two dimensional surface FESEM studies and HRTEM images. The overall formation of $TiO_2-based$ nanotube thin film can be summarized with three successive steps: (1) $TiO_2$ dissolving and amorphous $Na_2TiO_3$ deposition process; (2) layered $Na_2Ti_3O_7$ formation via spontaneous crystallization and rapid growth process; (3) formation of nanotube thin film via $Na_2Ti_3O_7$ splitting and multilayer scrolling process of (100) planes around the c axis of $Na_2Ti_3O_7$.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.28-33
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• 1996

This paper presents a position control of ultra-precision machine tool post using piezoelectric material. A stack-type piezoelectric actuator is employed in a hinge-type tool holder. An assumed linear transfer function of the practical nonlinear plant is established through the comparison of transfer functions and step responses in the experiments and the simulations. Several types of feedforward/feedback controllers are designed via computer simulations using the assumed linear transfer function, The position tracking control experiments are undertaken to show the control efficiency of each controller.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.207-209
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• 2005

Ultra wide band electromagnetic energy can be transmitted to a far field by emitting the nanoseconds high voltage pulse electromagnetic energy via an antenna. This UWB EM energy is expected to be used in post-packing pasteurization of food, detection of buried objects or underground water veins and caves and the treatment of waste water or polluted gas. The nanoseconds pulse forming for UWB generation using high voltage blumlein line and an ultrafast switch is mentioned.

• Journal of Chest Surgery
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• v.27 no.12
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• pp.1047-1051
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• 1994

Airway obstruction may be caused by extreme mediastinal shift and rotation after right pneumonecotmy or after left pneumonecotomy in the presence of right aortic arch.We experienced such a complication after right pneumonectomy, so called right postpneumonectomy syndrome. The patient was 28 years old female, and 4 month ago she had undergone right pneumonecotomy via video assisted thoracoscopic surgery[VATS] for endobronchial tuberculus dissemination and secondary pulmonary infection. She was treated by mediastinal repositioning which were composed of substernal fixation of pericardium and insertion of expandable prosthesis of 1000 cc capacity. She had good postoperative course and now she feels no obstructive symptoms.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.10a
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• pp.42.2-42
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• 1999