• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.33-37
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• 2006

Since 1993, the civil aviation community through RTCA (Radio Technical Commission for Aeronautics) and the ICAO (International Civil Air Navigation Organization) have been working on the definition of GNSS augmentation systems that will provide improved levels of accuracy and integrity. These augmentation systems have been classified into three distinct groups: Aircraft Based Augmentation Systems (ABAS), Space Based Augmentation Systems (SBAS) and Ground Based Augmentation Systems (GBAS). The last one is an implemented system to support Air Navigation in CAT-I approaching operation. It consists of three primary subsystems: the GNSS Satellite subsystem that produces the ranging signals and navigation messages; the GBAS ground subsystem, which uses two or more GNSS receivers. It collects pseudo ranges for all GNSS satellites in view and computes and broadcasts differential corrections and integrity-related information; the Aircraft subsystem. Within the area of coverage of the ground station, aircraft subsystems may use the broadcast corrections to compute their own measurements in line with the differential principle. After selection of the desired FAS for the landing runway, the differentially corrected position is used to generate navigation guidance signals. Those are lateral and vertical deviations as well as distance to the threshold crossing point of the selected FAS and integrity flags. The Department of Applied Science in Naples has create for its study a virtual GBAS Ground station. Starting from three GPS double frequency receivers, we collect data of 24h measures session and in post processing we generate the GC (GBAS Correction). For this goal we use the software Pegasus V4.1 developed from EUROCONTROL. Generating the GC we have the possibility to study and monitor GBAS performance and integrity starting from a virtual functional architecture. The latter allows us to collect data without the necessity to found us authorization for the access to restricted area in airport where there is one GBAS installation.

• Journal of Korean society of Dental Hygiene
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• v.18 no.4
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• pp.597-605
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• 2018

Objectives: This study examined the relationship between oral health symptoms and Internet usage of Korean adolescents for the purpose of identifying problems associated with Internet usage of adolescents and of preparing measures that can raise awareness on the importance of their oral health management. Methods: The data used in this study is from the 2015 Youth Health Behavior Online Survey (YHBOS). Data from all survey participants (n=68,043) were used in the final analysis, using SPSS Ver. 22.0. General linear models were constructed to analyze the relationship between oral health symptoms and Internet usage of adolescents. Results: In the relationship between Internet usage and oral disease symptoms, those who brush less than once a day during weekdays and weekend tended to use Internet at the highest levels: 72.5%, 78.3% (p<0.001). The following variables were found to be related with spending longer time at Internet: male students (p<0.001), students in lower grades (p<0.001), students with lower performance (p<0.001), and those from families of lower economic level (p<0.001). Moreover, those who brush their teeth less than once a day and those who experienced oral disease symptoms, such as pain during chewing, throbbing and shooting pain, and bad breath in the past year spent longer time at Internet. Conclusions: The above findings show that Internet usage and demographic characteristics of the adolescents are associated with their oral health management. Therefore, guidance and interventions are needed for adolescents with problematic Internet use, while continued education is also needed to raise awareness about the importance of oral health management during adolescence.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.494-500
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• 2002

본 연구의 목적은 DGPS와 자이로 센서를 장착하여 무인으로 콤바인을 직선주행, 선회 및 곡선주행, 직진주행 중 1 m 오프셋(offset) 주행시켰을 때, 무인 자율주행의 성능을 분석하고 개선하는데 있다. 콤바인의 무인자율주행 시스템은 콤바인의 현재위치를 인식하고, 주행하고 있는 콤바인의 주행방향을 감지하여 미리 설정된 경로를 따라 자율적으로 주행하며, 주행 중에 장애물이 검출되면 정지할 수 있도록 개발하였다. 콤바인의 무인 자율주행시스템은 DGPS의 입력 신호로부터 콤바인의 현재위치를 결정하고, 자이로 센서의 입력신호로부터 주행방향을 알 수 있다. 또한 장애물의 감지를 위한 초음파 센서, 콤바인의 주행방향을 조정하는 유압 작동부, 좌.우의 조향레버를 조정하는 서보모터 시스템, 마이크로 컴퓨터로 구성된 제어기와 입출력 인터페이스로 구성되어 있다. 콤바인 자율주행시스템의 프로그램은 DGPS 신호, 자이로 센서 등을 수신하는 수신 프로그램, DGPS 신호등으로부터 관련 변수들을 분석하여 콤바인의 조향수준을 결정하고, 유압실린더 등을 제어하는 제어 프로그램과 콤바인의 이동경로를 저장하는 저장 프로그램으로 구성되어 있다. 콤바인의 무인주행 실험결과 RMS 오차는 50 m 직선주행에서 7.52 cm, 20 m 직선주행 후 1 m 오프셋 된 30 m의 직선주행에서 21.85 cm, 20 m 직선주행 후 90$^{\circ}$선회하여 25 m 직선주행에서 7.55 cm, 반지름 23 m의 원주 사분면 곡선주행에서는 25.98 cm로 각각 나타났다. 소 구획의 포장에서 벼는 가로 방향으로 25~30 cm, 세로 방향으로 15~20 cm의 간격으로 심어져 있다. DGPS 신호에 의한 위치 결정을 할 때 자체 오차 10 cm를 고려하여도 콤바인이 직선구간 및 선회구간을 주행하며 수확작업이 가능함을 알 수 있었다. 그러나 곡선구간에서는 최대오차가 65.5 cm로 매우 크게 나타나, 콤바인을 무인 자율주행으로 수확하기에는 어려움이 있는 것으로 나타났다. 실제 포장은 이론적인 완전한 직선보다는 작은 굴곡이 있는 곡선의 형태가 이루어져 있으므로 주행 오차를 감소하기 위해서는 기계시각을 이용하면 보다 정밀한 조향을 이룰 수 있을 것으로 예상된다. 포장에서 DGPS 신호, 자이로 센서 등을 이용한 콤바인의 무인주행 장치는 무인 수확작업을 위한 가능성을 보여주었고, 일부의 센서의 기능을 개선하면 만족한 성능을 나타낼 수 있을 것으로 판단된다.

• Journal of Navigation and Port Research
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• v.35 no.6
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• pp.489-494
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• 2011

Present study introduces an implementation of product data management (PDM) that can be applied to the design of ship propulsion system. The PDM system is developed based on both object oriented software development environment and Open Scene Graph (OSG) library while the system architecture is modeled by the unified modeling language (UML). Suggested PDM system also integrates the modeling & simulation components required to estimate the performance of ship propulsion system as the product information is represented based on the 3-dimensional digital mock-up (DMU). Finally, functions of the implemented PDM system that is integrated with the M&S softwares are illustrated in order to suggest a practical guidance for the efficient design of ship propulsion system.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.3
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• pp.107-113
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• 2016

Visual discomfort is a common problem in three-dimensional videos. Among the methods to overcome visual discomfort presented in current research, disparity adjustment methods provide little guidance in determining the condition for disparity control. We propose a diaprity adjustment based on the characteristics of disparity distribution on visual comfort, where the visual comfort level is used as the adjustment paramter, in parallax barrier type auto-stereoscopic 3D display. In this paper, we use the horizontal image shift method for disparity adjustment to enhance visual comfort. The speeded-up robust feature is used to estimate the disparity distribution of 3D sequences, and the required amount for disparity control is chosen based on the pre-defined characteristics of disparity distribution on visual comfort. To evaluate the performance of the proposed method, we used a 3D equipment. Subjective tests were conducted at the fixed optimal viewing distance. The results show that comfortable videos were generated based on the proposed disparity adjustment method.

• Journal of Convergence for Information Technology
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• v.9 no.11
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• pp.55-61
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• 2019

This study was conducted to identify the predictors of the choice of regional small and medium hospitals by identifying the job preference, recognition of small and medium hospitals. For this purpose, data were collected from September 2018 to October 2018 for nursing students attending 4 universities in Gwangju and Jeollanam - do, and total of 476 questionnaires were analyzed using the SPSS / WIN 24.0 program. The results showed that 66.0% of nursing students selected region local small and medium hospitals. The factors influencing the choice of region small and medium hospitals were high school region, nursing school performance and recognition of small and medium hospitals. In order to increase the employment rate of nursing students to the region small and medium hospitals, nursing educators should provide personalized career guidance to students who want to work in small and medium hospitals and hospital personnel should establish various public relations activities and marketing strategies to raise recognition of small and medium hospitals.

• Steel and Composite Structures
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• v.33 no.1
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• pp.37-66
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• 2019

In cold-formed steel structures, such as trusses, wall frames and portal frames, the use of back-to-back built-up cold-formed stainless-steel lipped channels as compression members are becoming increasingly popular. The advantages of using stainless-steel as structural members are corrosion resistance and durability, compared with carbon steel. The AISI/ASCE Standard, SEI/ASCE-8-02 and AS/NZS do not include the design of stainless-steel built-up channels and very few experimental tests or finite element analyses have been reported in the literature for such back-to back cold-formed stainless-steel channels. Current guidance by the American Iron and Steel Institute (AISI) and the Australian and New Zealand (gAS/NZS) standards for built-up carbon steel sections only describe a modified slenderness approach, to consider the spacing of the intermediate fasteners. Thus, this paper presents a numerical investigation on the behavior of back-to-back cold-formed stainless-steel built-up lipped channels. Three different grades of stainless steel i.e., duplex EN1.4462, ferritic EN1.4003 and austenitic EN1.4404 have been considered. Effect of screw spacing on the axial strength of such built-up channels was investigated. As expected, most of the short and intermediate columns failed by either local-global or local-distortional buckling interactions, whereas the long columns, failed by global buckling. All three grades of stainless-steel stub columns failed by local buckling. A comprehensive parametric study was then carried out covering a wide range of slenderness and different cross-sectional geometries to assess the performance of the current design guidelines by AISI and AS/NZS. In total, 647 finite element models were analyzed. From the results of the parametric study, it was found that the AISI & AS/NZS are conservative by around 10 to 20% for cold-formed stainless-steel built-up lipped channels failed through overall buckling, irrespective of the stainless-steel grades. However, the AISI and AS/NZS can be un-conservative by around 6% for all three grades of stainless-steel built-up channels, which failed by local buckling.

• The Journal of Korean Society for School & Community Health Education
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• v.15 no.3
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• pp.81-93
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• 2014

Objectives: This study aims to find status of the oral health care, the oral health education program utilization and the oral health guidance according to the experience status of oral health education of special school teachers. Methods: The study subjects were 133 teachers at special schools in Seoul, Gyeonggi, Chungbuk and Jeonbuk regions. Results: 32.8% of the male and 67.2% of the female teachers have the oral health education experience. Barriers for the dental treatment to teachers with the education experience show in the order as 'disabled children's noncooperation' 49.2%, 'economic reasons' 37.7% and 'medical institution's rejection' 6.6% and, to teachers without the education experience, 'disabled children's noncooperation' 45.8%, 'economic reasons' 19.4% and 'not emergency situation' 13.9%(p<0.01). Regarding the necessity of arranged institution to manage the oral health, 91.8% of teachers with the oral health education answer as 'necessary'(p<0.05). Regarding the barriers on the performance of oral health program 27.9%, the majority of teachers with the education experience answer as 'insufficient administrative & financial support' and 36.1%, the majority of teachers without the education experience answer as 'insufficient understanding and expertise on the oral health education'. 86.9% of the teachers with the education experience and 62.5% of the teachers without the education experience are found to 'guide students on the oral health'(p<0.01). Conclusions: It was considered that various oral health education programs positively influential to the oral health care and education for disabled children should be developed according to the status of oral health education experience of special school teachers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.9
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• pp.1183-1189
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• 2021

There have been recently an increasing number of people working out at home. However, many of them do not have face-to-face guidance from experts, so they cannot effectively correct their wrong pose. This may lead to strain and injury to those doing home training. To tackle this problem, this paper proposes a video data-based pose classification and correction system for home training. The proposed system classifies poses using the multi-layer perceptron and pose estimation model, and corrects poses based on joint angels estimated. A voting algorithm that considers the results of successive frames is applied to improve the performance of the pose classification model. Multi-layer perceptron model for post classification shows the highest accuracy with 0.9. In addition, it is shown that the proposed voting algorithm improves the accuracy to 0.93.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.1
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• pp.815-824
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• 2019

It is not easy to present a generalized operating model because the operating environment of a sport event is composed of a complex matrix structure. In this study, we propose 'standardization' which provides guidance of concept and process of sport event management to solve this sports event management problem. To purpose complete of this study, the frame was developed by the international standard ISO 9001: 2015 is applied. The standards framework for sports event process management system structure proposed in this study consists of scope of application, citing standard, Terms and definitions, organizational situation, leadership, planning, support, operation, performance evaluation, and improvement. This sport event process management system standard can be applied to any organization that wants to host, prepare, and operate sport events regardless of the form or scale of the sport event. In addition, this standard was focused on process management of life-cycle stages of sporting events, therefor it was possible to manage interrelationships and dependencies between processes and processes.