• Journal of Positioning, Navigation, and Timing
• /
• v.12 no.3
• /
• pp.215-228
• /
• 2023

The State Space Representation (SSR) method provides individual corrections for each Global Navigation Satellite System (GNSS) error components. This method can lead to less bandwidth for transmission and allows selective use of each correction. Precise Point Positioning (PPP) - Real-Time Kinematic (RTK) is one of the carrier-based precise positioning techniques using SSR correction. This technique enables high-precision positioning with a fast convergence time by providing atmospheric correction as well as satellite orbit and clock correction. Currently, the positioning service that supports PPP-RTK technology is the Quazi-Zenith Satellite System Centimeter Level Augmentation System (QZSS CLAS) in Japan. A system that provides correction for each GNSS error component, such as QZSS CLAS, requires monitoring of each error component to provide reliable correction and integrity information to the user. In this study, we conducted an analysis of the performance of residual error bounding for each error component. To assess this performance, we utilized the correction and quality indicators provided by QZSS CLAS. Performance analyses included the range domain, dispersive part, non-dispersive part, and satellite orbit/clock part. The residual root mean square (RMS) of CLAS correction for the range domain approximated 0.0369 m, and the residual RMS for both dispersive and non-dispersive components is around 0.0363 m. It has also been confirmed that the residual errors are properly bounded by the integrity parameters. However, the satellite orbit and clock part have a larger residual of about 0.6508 m, and it was confirmed that this residual was not bounded by the integrity parameters. Users who rely solely on satellite orbit and clock correction, particularly maritime users, thus should exercise caution when utilizing QZSS CLAS.

• Journal of Digital Convergence
• /
• v.13 no.11
• /
• pp.63-70
• /
• 2015

The fierce competition of mobile messenger services (MMS) allows MMS providers to perform a variety of marketing campaigns and business activities to enhance user loyalty. The applied model in this study is based on Oliver's four-stage loyalty model for the formation processes of user loyalty about MMS. While social network formation and service quality are the key elements of cognitive loyalty, positive mood and negative mood are the key components of affective loyalty in the study. Conative loyalty is captured by commitment. The data of 249 KakaoTalk users at least five times for three months is empirically tested based on the research model using partial least squares. The analysis of test identifies that positive feeling and commitment significantly influences behavioral loyalty, whereas negative feeling plays a significant role in inhibiting behavioral loyalty. The findings of this study show that social network formation and service quality significantly affect only positive feeling. The analysis results reveal several insights that can help MMS managers understand the roles of cognitive, affective, conative, and behavioral loyalty in the MMS environment.

• Trans-
• /
• v.7
• /
• pp.49-80
• /
• 2019

As ageing society rapidly unfolds, it is becoming an even more important issue to secure wellbeing and happiness of senior citizens and the society as a whole. Growing talks on how culture and art positively affect the elderly led to more demands from the public on culture and art institutions to increase their social participations. Art museums too, as an art and cultural institution and a social education entity, are requested to play a bigger role in the effort to tackle the concerns derived from the ageing society. Korean art museums came up with senior programs since 2000, which makes it a relatively recent phenomenon. The consensus on the importance and needs of such programs has been around for a while in our society. However, effect measurement of these programs needs further research and discussion. This thesis examined the effect of senior programs using the Museum Wellbeing Measures Toolkit published in 2013. With the service quality research model, correlations were analyzed among program components, wellbeing effect, participant satisfaction and their willingness to re-enroll in order to produce a practical guidance on how to plan and operate the programs. To measure effect of senior programs and to analyze influencing factors would provide us with important data to prove the social responsibility and benefit art museums offer in our society. At the same time, such researches would contribute to enhancing the quality of current programs run by museums and give methodological suggestions on how to assess and improve senior programs.

• Structural Engineering and Mechanics
• /
• v.68 no.4
• /
• pp.459-473
• /
• 2018

Temperature fields and temperature deformations induced by time-varying solar radiation, shadow, and heat exchange are of great importance for the ride safety and quality of the maglev system. Accurate evaluations of their effects on the dynamic performances are necessary to avoid unexpected loss of service performance. This paper presents a numerical approach to determine temperature effects on the maglev train/guideway interaction system. Heat flux density and heat transfer coefficient of different components of a 25 m simply supported concrete guideway on Shanghai High-speed Maglev Commercial Operation Line is calculated, and an appropriate section mesh is used to consider the time-varying shadow on guideway surfaces. Based on the heat-stress coupled technology, temperature distributions and deformation fields of the guideway are then computed via Finite Element method. Combining guideway irregularities and thermal deformations as the external excitations, a numerical maglev train/guideway interaction model is proposed to analyze the temperature effect. The responses comparison including and excluding temperature effect indicates that the temperature deformation plays an important role in amplifying the response of a running maglev, and the parameter analysis results suggest that climatic and environmental factors significantly affect the temperature effects on the coupled maglev system.

• Architectural research
• /
• v.7 no.1
• /
• pp.49-54
• /
• 2005

Conventional studies have focused on the reduction in the water-cement ratio, the use of various admixtures, etc., to ensure the durability of reinforced concrete structures against such deterioration factors as carbonation and chloride attack. However, improvement in the concrete quality alone is not considered sufficient or realistic for meeting the recent demand for a service life of over 100 years. This study intends to improve the durability of reinforced concrete structures by improvement in the reinforcing steel, which has remained untouched due to cost problems, through subtle adjustment of the steel components to keep the cost low. As a fundamental study on the performance of Cr-bearing rebars in steel reinforced concrete structures exposed to corrosive environments, The test specimens were made by installing 8 types of rebars in concretes with a chloride ion content of 0.3, 0.6, 1.2, 2.4 and $24kg/m^3$. Corrosion accelerated curing were then conducted with them. The corrosion resistance of Cr-bearing rebars was examined by measuring crack widths, half-cell potential, corrosion area and weight loss after 155 cycles of corrosion-accelerating curing. The results of the study showed that the corrosion resistance increased as the Cr content increased regardless of the content of chloride ions, and that the Cr-bearing rebars with a Cr content of 5% and 9% showed high corrosion resistance in concretes with a chloride ion content of 1.2 and $2.4kg/m^3$, respectively.

• Korean journal of food and cookery science
• /
• v.30 no.2
• /
• pp.119-128
• /
• 2014

The purpose of this study is to propose the optimum adding rate of freeze-drying beet leaf powder, which has antioxidant components, that have superior DPPH radical extinction effects, in the Sulgidduk, a representative of steamed rice cake, which improve its functionality. According to the measured results on moisture contents and pH levels of Sulgidduk, with added freeze-drying beet leaf powder, the moisture contents have been significantly declined with increasing rates of added beet leaf powder. The pH levels of sample groups are within the range of 6.26-6.13. From the chromatography of measured results, lightness and yellowness have declined and redness have increased along with increasing rates of added beat leaf powder. According to the texture of measured results, the hardness, and chewiness have declined by the increasing the rate of added beet leaf powder. For the storage period, hardness, and chewiness have been inclined, but cohesiveness declines, with increased the storage period, while there are no changes from elasticity. The DPPH contents of Sulgidduk, with added freeze-drying beet leaf powder, inclined by increasing the rates of added beet leaf powder. The sensory test results of color, aroma and fragrance incline with increasing rates of added beet leaf powder. From acceptance test results, the sample group added with 3% receive the highest appraisals.

• Journal of the Korea Society of Computer and Information
• /
• v.23 no.12
• /
• pp.163-170
• /
• 2018

This study was conducted to investigate the effects of noise from dental clinics on workers and to establish a reduction plan. The noise generated by the treatment instrument(Ultrasonic scaler, Hand piece, 3-way syringe, Suction, Compressor) was measured in order to determine the characteristics(level, frequency) of the noise during medical treatment(Oral prophylaxis, Conservation treatment, Prosthesis treatment, Implant Scaling, Tooth eliminating). We also assessed the noise levels in dental clinic using evaluation indicators such as NR-curves and NRN. The results of the analysis showed that the noise generated during the treatment was 85dB(A) ~ 70dB(A) and that the high frequency component was dominant, which would affect the workers working at the dental clinic. The NR-curve analysis showed NR-67 to NR-83 and the high frequency components of 4kHz to 8kHz were predominant and far exceeded noise levels in the workplace. To minimize the noise damage of workers and to provide high quality medical service, it is necessary to establish countermeasures such as wearing a soundproof and periodic hearing tests.

• The Korean Journal of Food And Nutrition
• /
• v.32 no.3
• /
• pp.202-207
• /
• 2019

The objective of this study was to analyze labeling improvements and evaluate willingness to pay for health functional foods with a focus on the caution for intake. For this study, we conducted a survey on health functional food intake behavior, confirmation and improvements of cautions for intake. We assessed the willingness to pay for improvement of the caution for intake. Consumers anticipate improved immune function, and fatigue improvement after consumption of health functional foods. They mainly checked the function components related to efficacy and effectiveness, ingredients and their contents, ingestion amount and method, expiry date and best mode of storage, product name, and cautions associated with ingestion of health functional foods. They has been difficulties in obtaining sufficient caution information for intake from the current labeling method. Therefore, it is necessary to improve the labeling of caution for intake. The analysis indicated that about 5.14% of the respondents were willing to pay more if new labeling was introduces. However, there is still controversy over their safety, which is damaging to the consumers. Therefore, by providing consumers with accurate and detailed information on cautions for intake, it can contribute to securing safety and improving the quality of health functional foods.

• Journal of the Korean Data and Information Science Society
• /
• v.25 no.1
• /
• pp.37-52
• /
• 2014

The aim of this study was to understand home hospice care status and problem in Korea, and ultimately to develop the home hospice standard. This study was conducted as a part of a study on the institutionalization of the home hospice in Korea. A focus group interview with representatives of seven home hospice agency where have provided home hospice service for years was conducted. All of the participants agreed to the essential components for home hospice service including 24 hour on call service, multidisciplinary team visiting, and periodical team meeting. Visiting frequency was 1-3 times per week mostly by nurses. And they agreed requisitely to fulfill an office for home visiting nurses, storage space, and home visiting bags. The obstacles of providing home hospice were 1) no reimbursement system, 2) difficulties to change medication at home, 3) lack of inpatient beds for symptom control. Standardization of home hospice is critical to improve service quality and to develop reimbursement system. The findings of this study could be used as a basic data to develop home hospice standards and guidelines.

• The Journal of the Korea Contents Association
• /
• v.16 no.2
• /
• pp.277-286
• /
• 2016

This study proposes customized design process and methodology for wordpress web service based on structural analysis of wordpress theme components to enhance design quality of wordpress sites and increase designer's role in wordpress service domain. Firstly, we have identified problems of wordpress theme information through exploring theme search and theme information analysis in main wordpress theme markets. Secondly, we set up case study to experiment full process of wordpress theme based web design, then found unique problems in each design phases. As a result, customized design process and methodology are proposed for wordpress theme based web design.