• Journal of Navigation and Port Research
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• v.32 no.6
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• pp.499-503
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• 2008

As the conference result of MEPC in IMO, development of ballast water management system corresponding to newly established ballast water management standard (D2 regulation) of shipping is being made an active progress over the whole world. The ballast water management system should treat particular material of more than $10{\mu}m$ in high capacity of more than 500t per hour in the event of filtration process. Also, it is very difficult to develop a practical management system since a limited element which a narrow space of the ship should be designed in the minimal volume is assumed. Therefore, the study promoted a study on the next generation auto back wash media filter to overcome such a limited element. Also, the study performed pressure and flux measurement test followed by thickness of each filter medium for filtration by each size to grasp a relation between absorption and pressure at the time of vacuum filtration and mechanical analysis and turbidity change observation of filtered water after vacuum filtration.

• Korean Journal of Remote Sensing
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• v.37 no.5_2
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• pp.1235-1243
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• 2021

Geostationary Ocean Color Imager 2 (GOCI-II) on Geo-KOMPSAT-2 (GK2B)satellite was developed as a mission successor of GOCI on COMS which had been operated for around 10 years since launch in 2010 to observe and monitor ocean color around Korean peninsula. GOCI-II on GK2B was successfully launched in February of 2020 to continue for detection, monitoring, quantification, and prediction of short/long term changes of coastal ocean environment for marine science research and application purpose. GOCI-II had already finished IAC and IOT including early in-orbit calibration and had been handed over to NOSC (National Ocean Satellite Center) in KHOA (Korea Hydrographic and Oceanographic Agency). Radiometric calibration was periodically conducted using on-board solar calibration system in GOCI-II. The final calibrated gain and offset were applied and validated during IOT. And three video parameter sets for one day and 12 video parameter sets for a year was selected and transferred to NOSC for normal operation. Star measurement-based INR (Image Navigation and Registration) navigation filtering and landmark measurement-based image geometric correction were applied to meet the all INR requirements. The GOCI2 INR software was validated through INR IOT. In this paper, status and results of IOT, radiometric calibration and INR of GOCI-II are analysed and described.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.371-377
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• 2018

Navigational equipment standardization mode is a function which is used to standardize key functions, screen display and operation method of major navigation equipment. This is aimed towards to quickly and accurately checking information relevant for safe navigation. Currently, the International Maritime Organization is working on the development of guidelines for the application of navigational equipment in the standardized mode to the task of NCSR Sub-Committee. This study was conducted to investigate users' opinions and preferences in the application of standardization modes and to reflect them in the development of guidelines. In addition, the test program was designed to investigate user preferences for ECDIS among the navigational equipment, such as the types of information and functions that are necessary or preferentially required to perform navigational duties, and the screen configuration. In the study, 333 preference surveys were conducted in 35 countries using a web - based test program. ECDIS users confirmed the content and screen layout of their preferred ECDIS information when conducting navigation duty. The results of the study are significant as they contribute to the development of effective guidelines by presenting user requirements to be considered in the standardization mode.

• Korean Journal of Child Education & Care
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• v.18 no.4
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• pp.123-143
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• 2018

Objective: The purpose of this study was to investigate daycare center director's awareness of male teacher recruitment and need for effective male teacher recruitment. Methods: To this end, eight directors of child care centers with male teachers were selected as subjects of study. The data collection method was applied to the Focus Group Interview method, and a four interviews were conducted for two to two and a half hours. Results: After the interview data was analyzed, the contents were categorized into two major themes and six sub themes in awareness of male teacher recruitment by director of daycare center. The two major themes were (1) A vague fear of upcoming difficulties (2) The light and darkness of male teachers in the organization culture of childcare. Looking at the results, in a vague fear of upcoming difficulties theme includes administrative disadvantages, gender-related social atmosphere, and uncertainty about their role performance. Second, in the light and darkness theme includes women-centered organizational culture and adaptation, the vision of child care sites, and the role of male teachers at childcare sites. Next the contents were categorized into one major theme and four sub themes in need for effective male teacher recruitment by director of daycare center. The major theme was a male teacher's way into the daycare site, and sub five themes were expanding opportunities for child care experience and practices, a shift in the perception that it's not a man, it's an individual problem, maximizing the strengths of men, and improving the system. Conclusion/Implications: Based on these results, several specific implications of need for effective male teacher recruitment were suggested.

• Korean Journal of Optics and Photonics
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• v.30 no.4
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• pp.142-145
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• 2019

Normally, a corner cube retroreflector (CCRR) sheet is used as a retroreflective mirror array (RRMA) in a volumetric display. Each CCRR unit reflects light in the retroreflective direction, which is parallel to the incident light, and it makes a blurred image, as it shifts the position of light within its dimensions. Adopting a "curved planar wall" and "parabolic focusing" (x-axis), a hybrid-t(transverse direction)-RRMA is proposed, to improve the image quality and brightness. The improvement of image contrast is achieved by tuning a "linear v-shaped groove" structure to a "parabolic v-shaped groove". Also, the system has been simplified and the brightness enhanced 4 times by removing the half mirror.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.383-392
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• 2020

This study was conducted to understand the current status associated with challenging behaviors of adults with developmental disabilities and review the perception of workers at lifelong education centers for the developmentally disabled. To that end, a survey and a focus group interview were conducted. The findings were as follows. First, 85.4% of people working at lifelong education centers for the developmentally disabled had experienced injury in the past year due to challenging behaviors, and those who experience injuries responded that they suffered burnout, psychological trauma, and considered changing jobs. Second, in terms of preemptive response by the organization to address challenging behaviors, 'securing individual space' and 'preemptive identification of causes of challenging behaviors' ranked the highest, with 87.5% of the respondents giving this answer, respectively. For follow-up measures, 81.3% of organizations answered that they hold meetings on individual cases and provide supervision. Third, in terms of suggestions for ways to address challenging behaviors, establishment of an organization-wide system and cooperation with related organizations were cited as needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.488-493
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• 2020

The demand for hydrogen, which is considered an environmentally friendly energy source, is increasing, and at the same time, the fuel cell market is increasing continuously. This study aimed to establish a strategy for securing intellectual property rights on fuel cell by-product utilization technology for operating expenditure reduction of hydrogen-powered residential buildings. In this patent analysis, this study investigated Korean, American, Japanese, and European patents filed/published/registered by October 2019 and established a technical classification system and classification criteria through expert discussion. To reduce the operating expenditure of hydrogen-powered residential buildings, intellectual property rights will be improved using systems and methodologies involving cathode-side purified air, product water, and oxygen-depleted air captured with the dead-end mode operation of polymer electrolyte fuel cells.

• Journal of the Korea Society for Simulation
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• v.31 no.1
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• pp.11-18
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• 2022

Recently, research to classify human activity using imagery has been actively conducted for the purpose of crime prevention and facility safety in public places and facilities. In order to improve the performance of human activity classification, most studies have applied deep learning based-transfer learning. However, despite the increase in the number of backbone network models that are the basis of deep learning as well as the diversification of architectures, research on finding a backbone network model suitable for the purpose of operation is insufficient due to the atmosphere of using a certain model. Thus, this study applies the transfer learning into recently developed deep learning backborn network models to build an intelligent system that classifies human activity using imagery. For this, 12 types of active and high-contact human activities based on sports, not basic human behaviors, were determined and 7,200 images were collected. After 20 epochs of transfer learning were equally applied to five backbone network models, we quantitatively analyzed them to find the best backbone network model for human activity classification in terms of learning process and resultant performance. As a result, XceptionNet model demonstrated 0.99 and 0.91 in training and validation accuracy, 0.96 and 0.91 in Top 2 accuracy and average precision, 1,566 sec in train process time and 260.4MB in model memory size. It was confirmed that the performance of XceptionNet was higher than that of other models.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.8
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• pp.1172-1179
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• 2022

This paper describes a design of point scalar multiplier for public-key cryptography based on binary Edwards curves (BEdC). For efficient implementation of point addition (PA) and point doubling (PD) on BEdC, projective coordinate was adopted for finite field arithmetic, and computational performance was improved because only one inversion was involved in point scalar multiplication (PSM). By applying optimizations to hardware design, the storage and arithmetic steps for finite field arithmetic in PA and PD were reduced by approximately 40%. We designed two types of point scalar multipliers for BEdC, Type-I uses one 257-b×257-b binary multiplier and Type-II uses eight 32-b×32-b binary multipliers. Type-II design uses 65% less LUTs compared to Type-I, but it was evaluated that it took about 3.5 times the PSM computation time when operating with 240 MHz. Therefore, the BEdC crypto core of Type-I is suitable for applications requiring high-performance, and Type-II structure is suitable for applications with limited resources.

• Journal of Appropriate Technology
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• v.6 no.2
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• pp.126-135
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• 2020

Recently, with the development of the 4th Industrial Revolution era and the popularization of technologies the maker movement is spreading worldwide in various ways for education, entrepreneurship, and solving social problems. This paper introduces a case of establishing and operating a maker space in Tanzania, East Africa, one of the developing countries. iTEC Tech-shop was established in the first half of 2018 at the Nelson Mandela African Institution of Science and Technology (NM-AIST) in Arusha, Tanzania by Innovative Technology and Energy Center (iTEC), and has been operating for nearly two years. With the allocation of empty warehouse space from NM-AIST, physical facilities were established through the purchase and installation of equipment and hand tools. Based on the advice from Idea Factory of Seoul National University and Fab-Lab Seoul, iTEC Tech-shop operational system were established. Through a total of 7 technical workshops, iTEC Tech-shop provided training courses for about 180 local personnel. In addition, the smart Techshop test-bed project was promoted in order to improve the operation level along with securing sustainability of the Techshop. The case of the iTEC Tech-shop could be a useful case for institutions or organizations promoting the maker movement to developing countries.