• Journal of the Society of Naval Architects of Korea
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• v.32 no.1
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• pp.141-146
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• 1995

In this study the plastic buckling analysis of a simply supported plate under biaxial compression/tension loading is carried out considering the plastic compressibility. Plastic buckling of a biaxially loaded rectangular plate is governed by two kinds of mechanism, the tension strengthening and plastic weakening under which the optimal combination of tension and compression is obtained for the buckling strength. To consider the plastic compressibility, the Drucker-Prayer plastic potential is employed. General eigenvalue equations are derived for a rectangular plate within the framework of small strain plasticity and isotropic hardening.

• ETRI Journal
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• v.42 no.3
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• pp.366-375
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• 2020

The network traffic prediction of a smart substation is key in strengthening its system security protection. To improve the performance of its traffic prediction, in this paper, we propose an improved gravitational search algorithm (IGSA), then introduce the IGSA into a wavelet neural network (WNN), iteratively optimize the initial connection weighting, scalability factor, and shift factor, and establish a smart substation network traffic prediction model based on the IGSA-WNN. A comparative analysis of the experimental results shows that the performance of the IGSA-WNN-based prediction model further improves the convergence velocity and prediction accuracy, and that the proposed model solves the deficiency issues of the original WNN, such as slow convergence velocity and ease of falling into a locally optimal solution; thus, it is a better smart substation network traffic prediction model.

• Steel and Composite Structures
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• v.22 no.1
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• pp.183-201
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• 2016

Perforated steel beams can be optimised by increased beam depth and the moment of inertia combined with a reduced web thickness, favouring the use of original I-section beams. The designers are often confronted with situations where optimisation cannot be carried out effectively, taking account of the buckling risk at web posts, moment-shear transfers and local plastic deformations on the transverse holes of the openings. The purpose of this study is to suggest solutions for reducing these failure risks of tested optimal designed beams under applying loads in a self-reacting frame. The design method for the beams is the hunting search optimisation technique, and the design constraints are implemented from BS 5950 provisions. Therefore, I have aimed to explore the strengthening effects of reinforced openings with ring stiffeners, welded vertical simple plates on the web posts and horizontal plates around the openings on the ultimate load carrying capacities of optimally designed perforated steel beams. Test results have shown that compared to lateral stiffeners, ring and vertical stiffeners significantly increase the loadcarrying capacity of perforated steel beams.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.96-101
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• 2008

Due to improve form accuracy and surface roughness of a aspheric lens core that is made of Ni, the study is carried out on localization about a Subminiature Optics of Proximity and Wide Field of View. The required form accuracy P-V $0.2{\mu}m$ and surface roughness is Ra 10 nm. The design of experiment(DOE) is adopted to find a optimal cutting conditions which are spindle speed, depth of cut, feedrate. Finally, the effects of this study are replacing importation and strengthening competitiveness through the localization of the Subminiature Optics of Proximity and Wide Field of View.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.323-335
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• 1999

Spinal injuries are common these days and are increasing due to the increasing sports activities, auto-related accidents, and occupational incidences. Most of spinal injuries of strain and sprain are associated with trauma and resulted in loss of optimal musculoskeletal system in spinal column area. Some of these injuries requires surgical treatments. Fortunately, some people with spinal disorder are achieving outstanding results with the chiropractic care which utilizes muscle stimulation and strengthening, traction therapy, and spinal adjustments. These treatments using chiropractic table can ease pain by restoring alignment, improving mobility, and relieving pain and stiffness in neck and spinal areas. The purpose of this study was thus to gather the comprehensive information about spinal injuries, to define the specific dimensions, and to recommend functions of chiropractic table specially suited for Korean. This study was an integrated approach in applying the concepts of biomechanical correction of the musculoskeletal system. Also, this study was to utilize a knowledge of physics, ergonomics, and rehabilitation to the development of spine cure medicine.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.165-168
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• 2006

Carbon fiber reinforced polymer(CFRP) have superior mechanical and chemical properties in comparison with conventional materials. And post-tensioning method has been used for structural reinforcement of RC structures due to easy installation and good effect of resisting capacity of structures. But the higher cost of CFRP and the loss of prestressing force with time are considered the major problems to use it. In this study, CFRP Strips and external post tensioning for rehabilitation of old concrete structures were adapted and optimal combination of these methods is considered. A total of 17 concrete members were made and tested. The types and numbers of CFRP strips and post-tensioning types were selected as major test variables. From test results, it is shown that the concrete members that post tensioned and bonded CFRP strips has a pronounced effect on the strength and deformational behavior. This present study indicates that external temporally post tensioning can reduce the amount of CFRP strips required and the combination of temporally post tensioning and CFRP strips may meet the strength and ductility requirements of old structures.

• Journal of Environmental Science International
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• v.31 no.10
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• pp.891-899
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• 2022

This study investigated whether an educational program could alter students' perceptions of the causes of and solutions to climate change. On October 23, 2020, a 3-hour climate change educational program was provided to 400 high school students in Suncheon City, (Jeonnam Province, South Korea). According to the program, climate change represents a social dilemma, or tragedy of the commons; it also asserts that collective action aimed at strengthening government policy is the optimal solution to climate change, and concludes that motivated citizens should convey their opinions directly to the government through political action. After the program, the students made and shared placards calling for policy-based responses to climate change. Questionnaires completed by the students before and after the program revealed that their perceptions of the causes of and solutions to climate change changed significantly. This case study indicates that education programs have the potential to alter students' perspectives and promote actions aimed at mitigating and adapting to climate change.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.179-180
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• 2023

The adhesion performance of PCCs for crack repair of RC structures was greater in the case of using ultra high-early strength cement than in the case of using ordinary Portland cement, and the effect of mixing silica fume was higher in the case of ordinary Portland cement than that of ultra high-early strength cement. On the other hand, 130% of W/C was more fluid than 80% of W/C in the same P/C 80%, which increased the fillability and improved the strength, but the strength improvement effect was the greatest in adhesion in flexure. Through this study, the basic characteristics of the adhesion performance of PCCs were identified, and based on this, it is necessary to induce an optimal mixing design that can increase adhesion performance through various mixing designs.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3541-3547
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• 2013

Background: This cross-sectional observational study was undertaken to establish clinico-pathological characteristics of patients with gynecological malignancies, focusing mainly on symptoms, histological type and stage of the disease at presentation, in a tertiary care setting in Eastern India. Materials and Methods: In the gynecology out-patient clinic of a tertiary care hospital in Kolkata, India, the patients with suggestive symptoms of gynecological malignancies were screened. Their diagnoses were confirmed by histopathology. One hundred thirteen patients with histopathologically confirmed gynecological malignancies were interviewed. Results: The most frequently reported symptoms by the patients with histopathologically confirmed gynecological malignancies were excessive, offensive with or without blood stained vaginal discharge (69.0%), irregular, heavy or prolonged vaginal bleeding (36.3%) and postmenopausal bleeding (31.9%). The majority of the patients (61.0%) had squamous cell carcinoma on histopathological examination, followed by adenocarcinoma (30.1%). Nearly half of the patients (48.7%) were suffering from the Federation Internationale des Gynaecologistes et Obstetristes (FIGO) stage III, followed by stage II (40.7%) malignancy. Conclusions: This study highlights that most of the patients with gynecological malignancies present late at an appropriate health care facility. Ovarian cancer may often have non-specific or misleading symptomatic presentation, whereas cervical cancer often presents with some specific symptoms. These observations point to the need for increasing awareness about gynecological malignancies in the community and providing easily accessible adequate facilities for early detection and treatment of the disease by optimal use of available resources, i.e. strengthening the primary health care system.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.1
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• pp.23-29
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• 1984

Nowdays, the high strength aluminum alloys are broadly used for structural purpose, but the practical strengthening method by aging treatment are not much available. So that, in this study, in order to investigate the effect of aging treatment for strengthening on the fracture characteristics of the domestic high strength Al alloy (A2024BE), the variations of the aging temperature and time were taken after solution treatment. By microstructural examination, and by SEM fractographs of the fractures, the effects of aging temperature and time were investigated, considering on the fracture behaviour. The results obtained are as follows: 1) It was confirmed by microstructural investigation that the aging temperature of $190^{\circ}C$ and the aging time of 12hours were optimal to get more sound microstructure with distribution of uniform precipitation. 2) By step aging treatment, the proper aging time for obtaining the similar microstructure without any microstructural defects could be shortened in half the normal aging time. 3)By examining the SEM fractographs of the fracture surface, it was found that, regardless of the aging treatment time and temperature, all were intergranular ductile fractures, but the aging treatment at $190^{\circ}C$ for 12 hours resulted in dimple-type-transgranular and intergranular-ductile-frature.