• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.1
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• pp.94-106
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• 2020

Recently, the radio navigation method utilizing the GPS(Global Positioning System) satellite information is widely used as the method to measure the position of objects. As GPS applications become wider and fields based on various positioning information emerge, new methods for achieving higher accuracy are required. In the case of autonomous vehicles, the INS(Inertial Navigation System) using the IMU(Inertial Measurement Unit), and the DR(Dead Reckoning) algorithm using the in-vehicle sensor, are used for the purpose of preventing degradation of accuracy of the GPS and to measure the position in the shadow area. However, these positioning methods have many elements of problems due not only to the existence of various shaded areas such as building areas that are continually enlarged, tunnels, underground parking lots and but also to the limitations of accumulation-based location estimation methods that increase in error over time. In this paper, an efficient positioning method in a large underground parking space using Fingerprint method is proposed by placing the AP(Access Points) and directional antennas in the form of four anchors using WLAN, a popular means of wireless communication, for positioning the vehicle in the GPS shadow area. The proposed method is proved to be able to produce unchanged positioning results even in an environment where parked vehicles are moved as time passes.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.25 no.2
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• pp.98-108
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• 2016

In recent days, perhaps the biggest driver in new material development is the desire to improve restorations esthetics compared to the traditional metal substructure based ceramics or all-ceramic restorations. Each material type performs differently regarding strength, toughness, effectiveness of machining and the final preparation of the material prior to placement. For example, glass ceramics are typically weaker materials which limits its use to single-unit restorations. On the other hand, zirconia has a high fracture toughness which enables multi-unit restorations. This material requires a long time sintering procedure which excludes its use for fast chair side production. Hybrid ceramic material developed for CAD/CAM system is contained improved nano ceramic elements. This new material, called a Resin Nano Hybrid Ceramic is unique in durability of function and aesthetic base compositions. The new nano-hybrid ceramic material is not a composite resin. It is also not a pure ceramic. The material is a mixture of both and consists of nano-ceramic fillers. Like a composite, the material is not brittle and is fracture resistant. Like a glass ceramic, the material has excellent polish retention for lasting esthetics. The material is easily machined by chair side or in a dental lab side, could be an useful restorative option.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.10
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• pp.1009-1016
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• 2016

In this study, an educational program was developed. The program can perform the claim for examination of medical expense, which is one of NCS Competence Unit Elements for hospital administration. Considering various coding to complex compute and process, VB.Net was employed for this development. For database, ACCESS Database was used because it is easy to learn and use. The learning effects by the developed program are expected to be as follows. First, the composition of medical expense can be understood by analyzing Medical history and then selecting insurance code according to the Standard of Medical Care Code. Second, unit cost per score can be learned according to hospital class. Third, selection of Column (medical materials) and Column II(medical practice) can classify items of additional ratio. Fourth, because patient's payment rate on hospitalization and meal expense and use of special equipment are differently applied, user can know patient's payment rate by type and can calculate it. Fifth, additional amount is the amount calculated by additional ratio of Column II(medical practice), and user can learn additional ratio according by insurance type and hospital class. Sixth, user can learn self-pay rate by hospital class and understand the process that self-pay amount and claim amount are calculated according by self-pay rate.

• Journal of the Korean earth science society
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• v.26 no.6
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• pp.501-510
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• 2005

An analysis was done on the “inquiry sections” of Earth Science chapters of 10th grade science textbooks. The Inquiry sections were classified into different types and the frequencies of basic process skills, integrated process skills, and inquiry activities were measured in section to find out whether they sufficiently satisfy the requirements based on the 7th National Curriculum. The number of selected science textbooks that have been used in high school for this study were eleven. The number of inquiry tasks were on an average of 24.0. The types of inquiry sections and the elements of basic and integrated process skills were different in every textbooks. The number of inquiry activities were also different and analyzed more than those presented. They were not integrated activities but presented as scientific process skills. The basic process skills and integrated process skills presented in textbooks were $16\%\;and\;77.2\%$, respectively. However, the distribution of two kinds of process skills were analyzed to be $45.6\%\;and\;55.4\%$, respectively. In the process skills, the frequencies of inferring $(49.5\%)$ and data interpretation (68.7%) were the highest; however, the other process skills including recognizing problem, formulating hypothesis and generalization were not even presented in any of the text books. Due to the lack of the definitions of Science process skills and inquiry activities in the 7th National Curriculum, each text book defined these terms differently. It suggests that the meaning of inquiry, science process skills, and inquiry activities should be operationally defined in the national curriculum and the criteria for construction of inquiry activities are required.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.635-641
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• 2016

In order to drive a hybrid propulsion device which combines an engine and an electric propulsion unit, battery packs that contain dozens of unit cells consisting of a lithium-based battery are used to maintain the power source. Therefore, it is necessary to more strictly manage a number of battery cells at any given time. In order to manage battery cells, generally voltage, current, and temperature data under load condition are monitored from a personal computer. Other important elements required to analyze the condition of the battery are the internal resistances that are used to judge its state-of-health (SOH) and the open-circuit voltage (OCV) that is used to check the battery charging state. However, in principle, the internal resistances cannot be measured during operation because the parallel equivalent circuit is composed of internal loss resistances and capacitance. In most energy storage systems, battery management system (BMS) operations are carried out by using data such as voltage, current, and temperature. However, during operation, in the case of unexpected battery cell failure, the output voltage of the power supply can be changed and propulsion of the hybrid vehicle and vessel can be difficult. This paper covers the implementation of a high safety battery management system (HSBMS) that can estimate the OCV while the device is being driven. If a battery cell fails unexpectedly, a DC power supply with lithium iron phosphate can keep providing the load with a constant output voltage using the remainder of the batteries, and it is also possible to estimate the internal resistance.

• Strategy21
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• s.46
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• pp.123-157
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• 2020

This research focuses on one important type of non-traditional threat, maritime piracy, and tries to supplement previous research from the perspective of military power, especially naval power. When considering the elements of military power, naval power is a core independent variable to explain piracy incidents. Indeed, naval power can play a key role in solving piracy problems, since naval power is the only legitimate force to respond to piracy in the sea. It is natural that well equipped and trained naval power in the sea increases the probability of capturing pirates, which leads to increasing the costs of piracy and decreasing its occurrences. In addition, since naval combatant ships have more impressive weapons than those of pirate boats, just the presence of naval combatant ships could serve to deter piracy incidents in the sea. The main purpose of this research is finding the effectiveness of large multinational naval efforts to deter piracy incidents in Africa. With this research purpose, I analyze 771 piracy incidents that occurred in African states from 2009 to 2014. Furthermore, I include all 33 coastal states in Africa regardless of the experiences of piracy incidents in order to avoid selection bias, which is very common in quantitative-based piracy incidents research. The dependent variable of this research is frequency of maritime piracy incidents for a country-year and the independent variable is the number of multi-national naval warships that operate near Somalia. With this analysis, I find the large number of multi-state naval combatant ships are negatively related to piracy incidents. In other words, as a main means to counteract piracy incidents, multi-state naval combatant ships are conducive to reduce piracy incidents near Somalia, since it increases costs (being captured) of conducting piracy.

• 대한공업교육학회지
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• v.41 no.2
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• pp.134-150
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• 2016

This study has analyzed the subjects of transportation technology problem solving activities at Energy and Transportation Technology unit in the 12 kinds of middle school Technology Home Economics textbooks of the 2009 national revised curriculum. An analysis frame was developed with systems and environmental mediums which are common elements of transportation and the subjects were analyzed. As a result of this study, first, 8 kinds of subjects among 20 subjects in analysis frame were suggested in the textbooks. Second, according to the environmental, there are 13 terrestrial activities, 2 atmospheric activities, and 1 marine activity in the textbooks. However, there is no space related activity. Third, according to the system, there are 13 activities for the structure, 12 activities for the propulsion and suspension system, 5 activities related to the control system, and 1 activity regarding guidance system. Fourth, there are 4 kinds of problem solving activities depending on categorizing result of the analysis of the activities.

• Journal of Korean Home Economics Education Association
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• v.32 no.1
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• pp.167-184
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• 2020

The purpose of this study was to examine the effects of storytelling lessons using picture books on the resilience of adolescents and the parent-child relationships in the family unit of home economics subject in middle school. For this purpose, I selected picture books of five themes on family type, family relationship, family conflict, sexual violence, domestic violence, and family loss, and developed a teaching-learning process plan for 'Family class with picture book' using storytelling elements and techniques. The teaching-learning plan was applied to 194 middle school students in technology·home economics classes, and the learning effet was evaluated by comparing pre- and post-tests. As a result, the resilience level perceived by adolescents increased significantly after class, but no significant effect was found on self-expansion, which is a sub-factor of sociality. In the parent-child relationship of adolescents, the effect of instruction was shown in all areas, and the affectional bonds felt in the relationship with mother than with father showed higher increase. In the family unit of home economics, storytelling lesson through picture book seems to have a positive influence on the adolescents in their relationship with the family by bringing up the potential power in them to stand against the adversities they may face.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.575-580
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• 2013

The IMU(Inertial Measurement Unit) which is the expensive equipment has been used as a special limited area, usually in measurement of posture of applying to the areas of ship, submarine, aircraft and military equipment application. However, in the current situation, MEMS AHRS technology can replace the high-priced IMU in MEMS AHRS selected application field. In this paper, wireless hull motion measurement system was suggested for measuring key elements of ship's movement such as rolling, pitching and yawing using gyro, acceleration and magnetic sensors of AHRS. In order to reduce the error such as instantaneous acceleration, effects and vibration of geomagnetic, we have adopted the sensors equipped with Kalman filtering. The Wireless hull motion measurement system using AHRS sensors was tested in actual ship and it could easily be applied in limited installation circumstances of the ship. In the future, this system can be useful in the navigation safety and marine accident analysis by using with ship equipment such as INS or VDR in the maritime.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.3
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• pp.202-208
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• 2019

In this study, an active element pattern (AEP) of a printed dipole was analyzed in 1D and 2D arrays. First, an AEP of the printed dipole was obtained using the simulation in the 2D infinite array. The scan blindness in the 2D array occurred in the E-plane direction at around ${\pm}36^{\circ}$; however, it was barely observed in the 1D array. To analyze the cause of the scan blindness in the 2D array, the dispersion properties of a unit cell was obtained and compared with the scan blindness by frequency change. The difference between the scan blindness of the 1D and 2D arrays was clarified using the comparison of the Q value in the unit cell in the 1D and 2D arrays. Then, the coupling of the electric field in the E-plane direction was observed when nine elements were separated between the two ports in a linearly arranged dipole structure. Finally, the printed dipole array was fabricated, and an AEP was measured for the $11{\times}1$ and $11{\times}3$ sub arrays. The proposed theory was verified using these observations and by comparison with the simulation results.