• Nuclear Engineering and Technology
• /
• v.54 no.12
• /
• pp.4625-4635
• /
• 2022

A low-energy dielectric loaded accelerator with a non-uniform, multi-segment structure is studied and optimized. So far, no analytical solution is provided for such structures. Also, due to the existing nonlinear behavior and a large number of geometric parameters, the problem of numerical optimizations is complex. For this reason, a method is presented to design and optimize such structures using the Genetic Algorithm (GA). Moreover, the GA output results are compared with Trust Region (TR) and Nelder-Mead Simplex (NMS) methods. Comparative results show that the GA is more efficient in achieving optimization goals and also has a higher speed than the two other methods. Finally, an optimized accelerating tube is integrated into a proper coupler. Then, the accelerator is simulated for full electromagnetic investigations using the CST suite of codes. This design leads to a structure with a power of about 80 kW in the X-band, which delivers electrons to the output energy in the range of 300-459 kV. The length and outer diameter of the accelerating tube obtained are 10 cm and 1 cm, respectively.

• Development and Reproduction
• /
• v.19 no.1
• /
• pp.43-51
• /
• 2015

Connexin (Cx) is a complex which allows direct communication between neighboring cells via exchange of signaling molecules and eventually leads to functional harmony of cells in a tissue. The initial segment (IS) is an excurrent duct of male reproductive tract and expression of numerous genes in the IS are controlled by androgens and estrogens. The effects of these steroid hormones on gene expression in the IS during postnatal development have not extensively examined. The present research investigated expressional modulation of Cx isoforms in the IS by exogenous exposure to estrogen agonist, estradiol benzoate (EB), or androgen antagonist, flutamide (Flu), at weaning age. Two different doses of EB or Flu were subcutaneously administrated in 21-day old of male rats, and expressional changes of Cx isoforms in the adult IS were analyzed by quantitative real-time PCR. Treatment of a low-dose EB ($0.015{\mu}g/kg$ body weight) resulted in an increased expression of Cx31 gene and a decreased expression of Cx37 gene. A high-dose EB ($1.5{\mu}g/kg$ body weight) treatment caused an increase of Cx31 gene expression. Increased levels of Cx30.3 and Cx40 transcripts were observed with a low-dose Flu ($500{\mu}g/kg$ body weight) treatment. Treatment of high-dose Flu (50 mg/kg body weight) led to expressional increases of Cx30.3, 40, and 43 genes. Our previous and present findings suggest differential responsiveness on gene expression of Cx isoforms in the IS by androgens and estrogens at different postnatal ages.

• Korean Journal of Applied Biomechanics
• /
• v.15 no.1
• /
• pp.45-61
• /
• 2005

Stance is defined as any state in which the total mass of the body is supported by the feet. In order to maintain stance, the sum of gravito-inertial forces acting on the body must be registered by equal and opposite forces at the region of contact between the organism and the support surface. Balance is controlled by applying forces to the surface of support so as to maintain the body's center of mass vertically above the feet. for a muIti-segment organism, there can be a variety of ways in which balance can be controlled, since movements of different body segments can have similar effects on the control of balance. In general, the organism tends to have a body configuration that is aligned with gravito-inertial force when there are no external forces acting on it. If any segments of the body are not aligned with gravito-inertial force vector, a torque on that segment would tend to move the body's center of mass. The maintenance of postural stability is accomplished in humans by a complex neural control system. This requires organizing integrating and acting upon visual, vestibular, and somatosensory input, providing orientation information to the postural control system. The information necessary to control and coordinate movement is provided by the visual sense of eye position with respect to the surrounding surface layout, the vestibular sense of head orientation in the gravito-inertial space, and the somatic sense of body segment position relative to one another and to the support surface. In this study, perception and action capability was examined from various points of view. The underlying assumption of the study was that the change of postural configuration could be effected by organism, environment and task goal.

• Journal of Chest Surgery
• /
• v.9 no.2
• /
• pp.175-186
• /
• 1976

The cellular change of the pulmonary tuberculous lesions may be divided into two groups,exudative and proliferative form by their course and fate. In the most cases, the patients usually have very much complex type of cellular changes. Therefore, the shadows of the chest films in pulmonary tuberculosis are also much variable in nature. And Daniel said that knowledge of the pathology of tuberculosis and an appreciation of the method of progression and healing are essential to proper interpretation of the films. Author, having reviewed 33 cases of resected tuberculous lung obtained in N.M.T.H. for one year from Oct. '75 to Sep. '76 by surgical managements, classified the Pathological findings such as: 1) caseation only, 2) tuberculoma, 3) atelectatic lung 4) cavitary lesion and 5) atelectasis with cavity, and examined the relationship between the roentgenological characteristics of the chest films and the pathological process of tuberculous lesions of the resected lungs, The result were obtained as follows. (1) Tuberculoma was commonly appeared in $S_2$ segment in right and $S_6$ segment in left. (2) Atelectasis and destroyed lung were more commonly appeared in left lung than right, and their containing rate of cavity was 82%. (3) Cavities were mostly appeared in $S_1$ and $S_2$ segments of both lung and the appearance-rate of cavity on $S_6$ segment was higher in left than right. And among the cavitary lesions of the resected lung, cavity was not seen in the preoperative chest films in 22%. (4) The configuration, thickness and sharpness of the walls of cavities, which revealed the cavitary shadows in the preoperative chest films, were mostly depended on the degree of increased collagenous fiber of the wall, existence of perifocalitis, and more or less of the caseous masses on the inner surface of the cavity wall.

• The Journal of Natural Sciences
• /
• v.4
• /
• pp.191-220
• /
• 1991

A new texture segmentation-based image coding technique which performs segmentation based on roughness of textural regions and properties of the human visual system (HVS) is presented. This method solves the problems of a segmentation-based image coding technique with constant segments by proposing a methodology for segmenting an image texturally homogeneous regions with respect to the degree of roughness as perceived by the HVS. The fractal dimension is used to measure the roughness of the textural regions. The segmentation is accomplished by thresholding the fractal dimension so that textural regions are classified into three texture classes; perceived constant intensity, smooth texture, and rough texture. An image coding system with high compression and good image quality is achieved by developing an efficient coding technique for each segment boundary and each texture class. For the boundaries, a binary image representing all the boundaries is created. For regions belonging to perceived constant intensity, only the mean intensity values need to be transmitted. The smooth and rough texture regions are modeled first using polynomial functions, so only the coefficients characterizing the polynomial functions need to be transmitted. The bounda-ries, the means and the polynomial functions are then each encoded using an errorless coding scheme. Good quality reconstructed images are obtained with about 0.08 to 0.3 bit per pixel for three different types of imagery ; a head and shoulder image with little texture variation, a complex image with many edges, and a natural outdoor image with highly textured areas.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.37 no.4
• /
• pp.251-258
• /
• 2021

Dental trauma is very common in children and relatively young people, with the line of treatment depending on the time elapsed, age of the child, and tooth maturity. If the fractured segment is available and there is close approximation of the segment to the remaining tooth, reattachment of the fractured segment is a feasible option. This treatment offers several advantages, including the reestablishment of function, aesthetics, shape, shine and surface texture, in addition to the original contour and alignment of the teeth. The following cases present two different complex crown fracture cases that were treated using tooth fragment reattachment with fiber-reinforced composite post.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.50 no.11
• /
• pp.763-770
• /
• 2022

In an environment where multiple drones are operated, collisions can occur when path points overlap, and collision avoidance in preparation for this is essential. When multiple drones perform multiple tasks, it is not appropriate to use a method to generate a collision-avoiding path in the path planning phase because the path of the drone is complex and there are too many collision prediction points. In this paper, we generate a path through a commonly used path generation algorithm and propose a collision avoidance method using speed profile optimization from that path segment. The safe distance between drones was considered at the expected point of collision between paths of drones, and it was designed to assign a speed profile to the path segment. The optimization problem was defined by setting the distance between drones as variables in the flight time equation. We constructed the constraints through linearize and convexification, and compared the computation time of SQP and convex optimization method in multiple drone operating environments. Finally, we confirmed whether the results of performing convex optimization in the 20 drone operating environments were suitable for the multiple drone operating system proposed in this study.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.4
• /
• pp.28-39
• /
• 2016

The multi-mixed complex medical care facility consisting of mainly hospital and other associated facilities such as retail, office, accommodation, healthcare services, and so on, is currently recognized as a new segment in the real estate market. This study intends to identify the customer choice criteria for the development of multi-mixed complex medical care facility. Based on literature review and expert consultation, the 3 criteria with 12 sub-criteria for customer choice have been defined. And the AHP methodology has been implemented for the development of relative weight of those criteria depending on the type of facility including 'medical facility', 'supporting facility', 'healthcare service facility' and 'other ancillary facility'. Research findings indicated the implication for the optimal combination of facility development based on the customer choice criteria controlled by facility. Accordingly, this research intends to provide the guidance toward the development of multi-mixed complex medical care facility.

• Journal of the Korean Applied Science and Technology
• /
• v.41 no.3
• /
• pp.705-720
• /
• 2024

This study randomly assigned 24 middle-aged women to determine the effect of a 12-week combined exercise program on cardiovascular function and electrocardiogram-based ST segment and QRS in obese middle-aged women. Analysis of the results was conducted to verify differences within groups and between periods and groups. In terms of cardiovascular function, myocardial oxygen consumption showed a significant decrease in the experimental group during the resting phase and the highest intensity phase during exercise, and an interaction between group and period at rest was also observed. The heart rate recovery rate showed a significant decrease in the experimental group at 2 minutes of recovery, while in the control group, on the contrary, a significant increase was observed. The experimental group showed a significant decrease in systolic blood pressure, and an interaction between group and period was also observed. There was no change in diastolic blood pressure in both the experimental and control groups, and there was a statistically significant decrease in pulse pressure only in the experimental group at the 3-minute recovery stage. In the case of the electrocardiogram, the QRS height in the experimental group showed a significant increase in most cases at rest and at 3, 6, and 9 minutes during the recovery period, while there was no significant difference in the QRS period in both the experimental and control groups, and the ST segment height was significantly increased at rest in the experimental group. appeared to have increased. Therefore, summarizing the results of this study, it is believed that the 12-week combined exercise program has a positive effect in improving cardiovascular function, ventricular contractility in electrocardiograms, and myocardial ischemia in obese middle-aged women.

• Korean Journal of Bronchoesophagology
• /
• v.13 no.2
• /
• pp.9-16
• /
• 2007

Cricopharyngeal dysphagia(CPD), a common condition in the dysphagic patient, refers to the dysfunction of the upper esophageal sphincter complex(UESC), which is composed of the cricopharyngeus, inferior pharyngeal constrictor and the upper segment of the cervical esophagus. Primary CPD is the disease entity solely confined to dysfunctional UESC, while secondary CPD encompasses various conditions that accompany UESC dysfunction. For proper diagnosis and treatment of such entity, a thorough understanding of the complex anatomy and physiology of the upper esophageal sphincter. Adequate relaxation of the cricopharyngeal muscle in conjunction with anterosuperior excursion of the larynx by suprahyoid muscles and propulsion of food bolus are prerequisite for normal swallow, mechanisms of which if altered result in cricopharyngeal dysfunction. Of the various methods used for the diagnosis of cricopharyngeal dysphagia, videofluoroscopy remains the method of choice. Mechanical dilatation of the cricopharayngeus, cricopharyngeal myotomy and botulinum toxin injection and head-lift exercise have been used in clinical practice to relieve dysphagia in such patients. Such procedures have therapeutic effect in primary CPD, but so often fail to relieve swallowing dysfunction in patient with secondary CPD. We herein explain ancillary procedures that support these primary treatment options, which lead to successful treatment of dysphagia.