• Journal of Institute of Control, Robotics and Systems
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• v.13 no.12
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• pp.1252-1256
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• 2007

U-learning (ubiquitous learning) systems, which deliver learning materials anytime and anywhere, allow learners to watch live lectures on PDAs, tablet PCs and notebook computers via broadband and wireless Internet. These systems have various problems; first, terminal devices are expensive, and it is difficult to maintain their efficiencies. Secondly, Internet does not guarantee quality of service (QoS), and in general it does not provide real-time services. Finally, the security of these systems is weaker in a local network than in an external network. The USB-based terminal system based on the OSGi service platform was designed as a ubiquitous system, in order to solve those problems. The USB terminals, used in this system, are inexpensive, and it is easy to maintain their performances. Also, this system solves the problems of security in a local network and provides guaranteed QoS. To accomplish this, the number of USB terminals connected to the system has to be limited according to the formula proposed in our paper. This system uses the OSGi specification as a middleware. It supports the discovery mechanism of the USB terminals, maintenance and administration of the system. Finally, this paper shows a driver's license testing system as an example u-learning application1.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.99-104
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• 2015

Today the most efficient way to transport the natural gas is carried via the liquid. In order to liquefy the natural gas to be cooled to $-160^{\circ}C$ or less. Cooling method has a number of different ways. In this paper, we studied control method for the representative liquefaction process, C3MR. Natural gas liquefaction control is a tool that can maintain the quality of natural gas is a means to ensure stable operation. Analyzing the C3MR process, and select the control parameters for the control valve. We find control structure for mixed refrigerant cycle through the step response. A control result obtained through the dynamic simulation arbitrarily given a disturbance was found to maintain a steady-state results.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.1
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• pp.261-271
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• 2019

The study aims to investigate corporate social responsibility (CSR) best practices of the world automotive industry - Peugeot, BMW, Ford, Hyundai and Toyota among others - and recommend that they plan their business strategies and managerial responses accordingly. Based on the comparative research and case studies, this research finds that all five automobile manufacturers have taken very similar measures and actions in order to establish and maintain a high level of CSR practices. Sustainability was a core value in all five companies and served as a guiding principle in every aspect and approach of their business. This study finds that all five companies have CSR strategies in place to increase energy efficiency as well as reduce the usage and wastage of water in their production and plants. This research also finds that all companies monitor their suppliers and their own production process to ensure that they maintain their CSR standards. More impressively, this sustainable management practice is transferred along the companies' supply chain through education and training. Their suppliers and business partners are closely monitored to make sure that their high CSR standards are respected and followed. However, we find that there also are some differences in terms of their CSR deliveries and activities.

• Journal of Korean Neurosurgical Society
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• v.64 no.6
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• pp.843-852
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• 2021

The purpose of this review was to synthesize the research on global spinal alignment and reciprocal changes following cervical or thoracolumbar reconstruction surgery. We carried out a search of PubMed, EMBASE, and Cochrane Library for studies through May 2020, and ultimately included 11 articles. The optimal goal of a truly balanced spine is to maintain the head over the femoral heads. When spinal imbalance occurs, the human body reacts through various compensatory mechanisms to maintain the head over the pelvis and to retain a horizontal gaze. Historically, deformity correction has focused on correcting scoliosis and preventing scoliotic curve progression. Following substantial correction of a spinal deformity, reciprocal changes take place in the flexible segments proximal and distal to the area of correction. Restoration of lumbar lordosis following surgery to correct a thoracolumbar deformity induces reciprocal changes in T1 slope, cervical lordosis, pelvic shift, and lower extremity parameters. Patients with cervical kyphosis exhibit different patterns of reciprocal changes depending on whether they have head-balanced or trunk-balanced kyphosis. These reciprocal changes should be considered to in order to prevent secondary spine disorders. We emphasize the importance of evaluating the global spinal alignment to assess postoperative changes.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.4
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• pp.1-7
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• 2018

The floating sculptures in the form of ad-ballon commonly used ropes in order to hold on. Relatively air flow is much less indoor than outdoor. Users of buoyancy sculptures hope to be able to maintain their desired posture without being fixed. This study applied drone technology to buoyancy sculptures. The drones can be moved vertically and horizontally, and the posture can be maintained, so buoyancy sculptures are easy to apply. Therefore, we have studied the control system of buoyancy sculpture using drone technology. Also, a control system that can maintain the desired posture at a constant height was studied. The overall shape was a light fiber material and helium gas for zero buoyancy to support the sculpture. The system configuration was STM32F103CB from ARM. In addition, the gyro and acceleration, geomagnetic sensors and motors are composed of small and medium size BLDC motors. The scheduling of the control system in the configuration of the control device was carefully considered. Because the role of the whole component becomes very important. The communication between the components is divided into the sensor fusion and the interface communication with the whole controller. Each communication technology is designed to expand. This study was implemented to actively respond from the viewpoint of posture control using the drone technology.

• Journal of the Korea Safety Management & Science
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• v.24 no.1
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• pp.11-19
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• 2022

In order to find out the management and sanitation status of protective gear provided at the construction site, a case study and survey were conducted by visiting the site. As a result of the case study, inspection and management, disinfection, and storage of protective equipment were insufficient in both workplaces with less than 50 employees and workplaces with more than 100 employees. As a result of the survey, workers(66.2%), said they did not know how to identify hard hats(67.6.%), how to identify bad hard hats(60.8%), and how to identify bad safety belts (73.0%), even though workers(66.2%) were educated on protective gear, and those in charge of protective gear Non-specified(56.8%), regular inspection of the provided protective equipment was not performed(82.4%), and disinfection was not performed(90.5%). Therefore, as a management plan to maintain the performance of personal protective equipment, educational aspects, regular training on protective equipment, training on how to identify defective protective equipment, management of recording papers, technical aspects, strengthening of standards for placement of dedicated safety managers in small workplaces, participation of workers' representatives when selecting protective equipment, and selection of protective equipment for workers Providing opportunities, administrative aspects of protective equipment regulation and management, introduction of sanitary and cleanliness system, and selection of personnel in charge of protective equipment management were suggested.

• Journal of the Korean Society of Clothing and Textiles
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• v.47 no.2
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• pp.337-352
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• 2023

This study develops a t-shirt design that align bones and balance muscles in order to maintain proper posture using the basic concepts of symmetry. First, theoretical and 3D design studies, existing literature on proper and improper posture, and the basic concepts of symmetry are studied to create the design. Next, the 3D design process applies bilateral, rotational, and scaling symmetries to design the inner lines from the basic application of symmetry. A two-stage design process is used, whereby the strain map and pressure points are analyzed using the CLO virtual clothing software, and the most effective design is determined through virtual testing. The results show that the Y+)( and X+― design, which combines the position and type of inner lines, is the most effective for posture correction and maintenance. Overall, this study helps create a theoretical and practical basis for exploring and understanding basic lines appropriate for the human body, and subsequently, for developing various products that maintain posture more accurately and precisely.

• Asia Marketing Journal
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• v.15 no.2
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• pp.99-116
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• 2013

This study examines whether product promotions are influenced by the market standing of promoted products, using social comparison theory (upward versus downward comparisons). It is hypothesized that people in possession of a product that is inferior to the one on promotion express less discomfort about the promotion and use the information more than do people in possession of a superior product. People in possession of an inferior product may also exhibit more positive attitudes toward the product on promotion, but may show poorer attitudes toward their own possessed product than do people with a superior product. This is because people in an inferior socioeconomic position show a strong motivation to improve themselves through upward social comparison, whereas people in a superior socioeconomic position maintain a strong sense of superiority in downward social comparison, which suggests strong endowment effects. The findings mainly support the hypotheses, and suggest that sales promotions are more effective for people who currently own an inferior product, but not for people with a superior product, who have a strong motivation to maintain their sense of superiority. The findings also imply that, in order to attract consumers in the superior market, managers for inferior products need to turn to methods other than sales promotions, which may include introducing a new brand or sub-brand, or emphasizing luxury and modern features. In contrast, managers for superior products may emphasize product functions and attributes of superior products in their promotions, as people with inferior products may consider such information as benefits of the superior products.

• Journal of Wind Energy
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• v.14 no.4
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• pp.13-20
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• 2023

A self-climbing crane (SCC) system is under development for the installation and maintenance of wind turbines. It can move vertically along the wind turbine tower by itself. One of the key components of the SCC system is the clamping pad to maintain a safe position on the wind turbine tower. The SCC system can maintain its position on the tower from the frictional force generated between the surfaces of the clamping pads and the tower. If the frictional force provided by the clamping pads are insufficient, the SCC system cannot stay in the vertical position on the tower. Therefore, the development of clamping pads with sufficient frictional force is very important for the SCC system. At the same time, the operation of the SCC system should not damage the paint coating of the wind turbine tower. In order to verify that the frictional force is sufficient and that frictional and compressive forces do not cause damage to the paint, a number of combined compression and shear loading tests were conducted using a test device prepared for this study. The details regarding the test specimens, test procedure, and test results are summarized in this paper.

• Biomedical Science Letters
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• v.30 no.2
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• pp.49-55
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• 2024

This study uses the 9th 1st year (2022) National Health and Nutrition Examination Survey to analyze the relationship between sleep time and the number of existing teeth for the adult population aged 19 or older to provide basic data on related dental development. There is a purpose. This program is designed to improve sleep quality and maintain the number of viable teeth in the future. The subjects were 53,220 people who answered the questions. The collected data were analyzed using SPSS (ver 21.0) program using complex samples, and chi-square analysis and logistic return analysis were performed. As a result, it was found that 2.537 times more existing teeth remained when sleep time was 9 hours or more than when sleep time was 6 hours or less, and there was a statistically significant difference. In conclusion, it is necessary to recognize the importance of the number of remaining teeth and to make efforts to manage personal immunity, such as sleep management for adults, and to promote and prevent oral care and oral health education in order to maintain the number of remaining teeth.