• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.293-300
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• 2008

Efficient designing of SRM Grains in the field of Rocketry is still the main test for most of the nations of world for scientific studies, commercial and military applications. There is a strong need to enhance thrust, improve the effectiveness of SRM and reduce mass of motor and burning time so as to allow the general design to increase the weight of payload/on board electronics. Moreover burning time can be increased while keeping the weight of the propellant and thrust in desired range, so as to give the time to control / general design group in active phase for incorporating delayed cut off if required. A mathematical design, optimization & analysis technique for Slotted Tube Grain has been discussed in this paper. In order to avoid the uncertainties that whether the Slotted Tube grain configuration being designed is best suited for achieving the set design goals and optimal of all the available designs or not, an efficient technique for designing SRM Grain and then getting optimal solution is must. The research work proposed herein addresses and emphasizes a design methodology to design and optimize Slotted Tube Grain considering particular test cases for which the design objectives and constraints have been given. In depth study of the optimized solution have been conducted thereby affects of all the independent parametric design variables on optimal solution & design objectives have been examined and analyzed in detail. In doing so, the design objectives and constraints have been set, geometric parameters of slotted tube grain have been identified, performance prediction parameters have been calculated, thereafter preliminary designs completed and finally optimal design reached. A Software has been developed in MATLAB for designing and optimization of Slotted Tube grains.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.536-537
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• 2014

In this paper, it suggested Android smart phone application for users who want to find valley at summer. To provide correct information, we used Korea Tourism Organization's tourism information database and to provide tourism information and map service at once we linked Naver map. Search valley application can search valley by using country's region name and keyword by using map and GPS. we can find restaurants accomodations around your location. we can get restaurants and accommodations by control distance so we can get phone number, pictures and detail information about searched data. Also, you can bookmark valley where you want to go and you can search of delete bookmarked valley whenever you want. you can share opinion by writing postscribe about the valley where application user went. for developer and users amicable communication we made Q&A board.

• Korean Journal of Community Nutrition
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• v.24 no.3
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• pp.183-196
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• 2019

Objectives: College is an important time for students to establish their identity as an independent subjects and develop a foundation to maintain a healthy adulthood. However, after female students become college students, their eating habits are likely to become more irregular and they may experience various health problems because of excessive weight control. Therefore, this study was conducted to investigate the dietary behaviors and blood clinical indices of female college students by residence types. Methods: A total of 374 subjects were classified as home group, self-boarding group or boarding group according to residence type. Dietary habits, frequency of food intake, and eating attitudes were examined through questionnaires and anthropometric measurements and blood clinical indices were analyzed. Results: The meal most frequently skipped by female college students was breakfast, and the frequency of skipping breakfast was significantly lower in the home group than other groups. Most college students recognized that their eating habits had worsened since becoming college students, with the self-boarding group in particular feeling that their eating habits changed negatively. The consumption frequencies of protein foods, fruits, dairy products, seaweed, and fatty meats were significantly lower in the self-boarding group than other groups. The home group ate food cut into smaller pieces, while the self-boarding group tried new and rich foods. Residence types did not affect blood clinical indices. Conclusions: The self-boarding group had inadequate dietary habits compared to the home group. Although residence type did not affect the blood clinical indices, the students still had poor dietary habits. Therefore, proper nutrition education is needed to improve the nutritional status of college students, especially those that self-board.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.321-326
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• 2021

Wireless communication is a core technology constituting the Internet of Things (IoT), but there is no suitable educational equipment to learn various wireless communication technologies used in the Internet of Things through practice. This paper deals with the development of advanced education and training equipment that can perform various IoT wireless communication practices. It uses an Arduino mega board as a device to control various sensors. As wireless network technologies to send and receive the sensing date wirelessly, it makes use of RFID/NFC and Bluetooth among WPAN technologies, WiFi among WLAN technologies and LoRa and 2.4GHz wireless transceiver among WWAN technologies. In addition, GPS, infrared communication, I2C communication, and SPI communication are organized so that various IoT wireless communication technologies can be learned through practice. In addition, since the educational equipment developed in this paper is equipped with two devices, it is designed to perform transmission and reception experiments for wireless network technology within the equipment.

• Journal of the Korea Society of Computer and Information
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• v.26 no.1
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• pp.209-216
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• 2021

In this paper, I developed a scenario-based admission management virtual reality (SAM VR) content for practical training for nursing students and verified the effectiveness. The SAM VR contents used in the study was developed by the researcher using Gear VR and smartphone according to the standard practical procedure suggested by the Korea Acreditation Board of Nursing Education and Evaluation. In the 30 experimental groups who received practical training using SAM VR contents, learning flow, learning confidence, and learning satisfaction increased statistically significantly after the practical training (p<.001). In the control group, who received practical training in the traditional way, learning confidence increased after the practical training (p<.005), but there was no change in learning flow and learning satisfaction (p>.005). It was verified that the SAM VR contents are effective practical education contents for nursing students' learning flow, learning confidence and learning satisfaction.

• Journal of Korean society of Dental Hygiene
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• v.21 no.3
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• pp.311-318
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• 2021

Objectives: The purpose of this study was to understand the level and patterns of college adjustment, major satisfaction, academic engagement, and attention deficit hyperactivity disorder (ADHD). This study examined the factors influencing adaptation to college life. Methods: This study was approved by the institutional review board of 00 university. We analyzed 166 survey data responses collected by distributing questionnaires from June 1 to July 2, 2020. Statistical product and service solutions version 23.0 was used for statistical analyses. The data were presented as frequencies and percentages or means and standard deviations, and pearson correlation analysis and multiple regression analysis were performed. Results: There was a significant difference in the average score of major satisfaction according to the type of college (university) and grades. For college adjustment, there was a significant difference in the average score according to major grades. Academic engagement showed a significant difference in the average score according to the college type and grade. Major satisfaction, college adjustment, and academic motivation showed significant positive correlations among the variables, whereas ADHD, major satisfaction, and college adjustment showed a significant negative correlation. Multiple regression analysis revealed that major satisfaction (p<0.001) and academic motivation (p<0.001) were factors affecting college adjustment (p<0.05). Conclusions: It is necessary to develop and apply specific and systematic adaptation programs to improve the understanding, control, and guidance methods for college students and to promote human relations, such as school life and social life.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1673-1678
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• 2019

There are various networks and communication methods are used in industrial communication. Enterprises need to convert communications between industrial devices and networks for production line expansion, factory upgrades, network segmentation, and SI. This requires designers manufactured by many manufacturers to provide communication equipment for data or protocol conversion in order to connect and transmit various other mechanical devices to the network. This paper designed industrial communication gateway that can support the transformation of industrial communication protocol using multi-layered communication module. Industrial communication gateways have a structure that connects individual communication modules using RS485 communication to multiple layers. Each communication module consisted of analog and digital data card, LAN, and CAN-enabled card. The main board processor used Atmega micro-processor, and the RS485 slot was placed to have a multi-layer communication module structure. These additive layer type communication modules support analog and digital I/O functions and LAN and CAN for wide use in industrial communication control and monitoring.

• Journal of the FoodService Safety
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• v.2 no.2
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• pp.97-102
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• 2021

The purpose of this study was to investigate the effect of developing and continuously providing on-line hygiene education programs on the improvement of hygiene conditions in children's cafeterias. As a result of the 2020 sanitation and safety checklist analysis, 6 items (personal hygiene, separate use, clean ventilation, temperature control of refrigerators, country of origin, food distribution) were derived and on-line hygiene education programs for each of 6 items were produced. ① Customized educational materials and self-inspection checklists were provided to 208 children's cafeterias. After that, educational videos were provided through Kakao Talk twice a week for 6 months, and they were made available for viewing at any time through YouTube upload, ③ Kakao Talk Through this, a quiz related to the educational video was conducted to give feedback for interaction with the cook. As a result of analyzing the total hygiene and safety checklist score of all registered facility catering centers by visit order, in 2020 it was 82.8 points/100 points, but in 2021, it was 84.2 points (1st round), 89.3 points (2nd round), 91.4 points (3 points) The score improved significantly (p<0.001) as the on-line hygiene education program continued. As a result, significant (p<0.001) changes were observed in the items of 'Knife, chopping board' and 'Sanitation clothes, sanitary hat, sanitary shoes, apron, and sanitary gloves', confirming a clear improvement effect. Therefore, it is considered that the on-line hygiene education program will play a positive role in showing a lasting effect on improving hygiene management in children's cafeterias.

• Journal of the Korea Convergence Society
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• v.13 no.3
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• pp.191-196
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• 2022

Unlike an international combustion engine car, a battery-powered electric vehicle requires an additional heat source for its heating system. A high-voltage coolant heater has the advantages of high efficiency and a wide operating temperature range. In its development, the geometry design of the coolant flow path is essential. This paper presents the thermal flow simulations of a 7kW high-voltage heater with symmetric serpentine flow channels arranged parallelly. The heater performance was evaluated from the simulation results in terms of the pressure and temperature differences and the flow uniformity. The proposed design showed a greater flow resistance and similar heat exchanging capability than the existing parallel serpentine design. It has the advantage of a relatively wide low-temperature surface area, where the control circuit board susceptible to high temperatures can be located.

• The Journal of Korean Physical Therapy
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• v.33 no.6
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• pp.272-277
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• 2021

Purpose: The purpose of this study is to confirm the effect of static stretching of the plantar flexor for 5 minutes on balance and ankle muscle activity when walking in young adults. Methods: This study experimented on 20 healthy college students without vestibular and musculoskeletal diseases. Subjects performed static stretching intervention of plantar flexor for 5 minutes on a stretch board set at 15° to 25° Balance was measured four times before intervention (pre), after intervention (post), 5 minutes after intervention (post 5 min), 10 minutes after intervention (post 10 min), and ankle muscle activity was measured during walking. For the analysis and post hoc analysis, one-way Repeated Measure ANOVA and Fisher's LSD (Last Significant Difference) was performed to find out the change in balance and the activity of ankle muscles before static stretching, pre, post, post 5 minutes rest, post 10 minutes rest. Results: There was no significant difference in weight distribution index (WDI) in balance, but stability index (ST) showed a significant difference, and there was also a significant difference in correlation pre, post, post 5min rest, post 10 minutes rest (p<0.05). There was no significant difference in ankle muscle activity during walking in Tibialis anterior (TA), Medial gastrocnemius (GM), and Lateral gastrocnemius (GL) (p>0.05). Conclusion: The stability index (ST) increased significantly immediately after static stretching and decreased after 5 minutes. After static stretching, at least 5 minutes of rest are required to restore balance.