• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.81-87
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• 2006

The rubblization technique is breaking the aged concrete pavement slab into rubblized concrete aggregate, and use it as an base material at its original position, then builds overlay above the rubblized base. This method has been successively used in USA due to the advantage of good constructibility, cost-effectiveness as well as the capability of preventing of reflection cracks. However, constructibility and economic performance of rubblization on typical Korean concrete pavements needed to be investigate since to typical Korean concrete pavements have thick slab, as well include lean concrete subbase course. Multi-head type breaker suitable for Korean condition was designed and developed. This multi-head type breaker was designed to rubblize old concrete to the suggested optimum rubblized-depth and rubblized-concrete-aggregate size to prevent reflection crack and maintain high bearing capacity. This machine was used for the test of rubblization of old concrete pavement on a non-use old concrete and a in-serviced road. In these two tests, engineering properties of rubblized base and constructability and cost were investigated. In both tests, the old concrete rubblized to targeted size and depth, and high-level bearing capacity was achieved. Also, superior constructability and lower cost compared with traditional reconstruction was examined.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.13-19
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• 2016

The PSK (Pre-shared Secret Key) based method is appropriate for the IoT environment consisting of lightweight devices since this method requires less computing time and energy than the method to configure the session key based on the public key algorithm. A fundamental prerequisite for the PSK based method is that PSK should have been configured between the communication entities safely in advance. However, in case of a small sensor or actuator, no input and output interface such as keyboard and monitor required for configuration exists, so it is more difficult to configure PSK for such lightweight devices safely in the IoT environment than the previous Internet devices. Especially, normal users lack expertise in security so they face difficulty in configuration. Therefore, the default value configured at the time of manufacturing at factories is used or the device installer configures PSK in most cases. In such case, it is a matter for consideration whether all installers and manufacturers can be trusted or not. In order to solve such problem, this paper proposes a secure bootstrapping scheme, which utilizes the NFC (Near Field Communication) as an OOB (Out-Of-Band) channel, for lightweight devices with limited resources.

• The Korean Journal of Air & Space Law and Policy
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• v.18
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• pp.135-183
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• 2003

Aerospace force is a determining factor in a modem war. The combat field is expanding to space. Thus, the legitimacy of establishing aerospace force is no longer an debating issue, but "how should we establish aerospace force" has become an issue to the military. The standard limiting on the military use of space should be non-aggressive use as asserted by the U.S., rather than non-military use as asserted by the former Soviet Union. The former Soviet Union's argument is not even strongly supported by the current Russia government, and realistically is hard to be applied. Thus, the multi-purpose satellite used for military surveillance or a commercial satellite employed for military communication are allowed under the U.S. principle of peaceful use of space. In this regard, Air Force may be free to develop a military surveillance satellite and a communication satellite with civilian research institute. Although MTCR, entered into with the U.S., restricts the development of space-launching vehicle for the export purpose, the development of space-launching vehicle by the Korea Air Force or Korea Aerospace Research Institute is beyond the scope of application of MTCR, and Air Force may just operate a satellite in the orbit for the military purpose. The primary task for multi-purpose satellite is a remote sensing; SAR sensor with high resolution is mainly employed for military use. Therefore, a system that enables Air Force, the Korea Aerospace Research Institute, and Agency for Defense Development to conduct joint-research and development should be instituted. U.S. Air Force has dismantled its own space-launching vehicle step by step, and, instead, has increased using private space launching vehicle. In addition, Military communication has been operated separately from civil communication services or broadcasting services due to the special circumstances unique to the military setting. However, joint-operation of communication facility by the military and civil users is preferred because this reduces financial burden resulting from separate operation of military satellite. During the Gulf War, U.S. armed forces employed commercial satellites for its military communication. Korea's participation in space technology research is a little bit behind in time, considering its economic scale. In terms of budget, Korea is to spend 5 trillion won for 15 years for the space activities. However, Japan has 2 trillion won annul budget for the same activities. Because the development of space industry during initial fostering period does not apply to profit-making business, government supports are inevitable. All space development programs of other foreign countries are entirely supported by each government, and, only recently, private industry started participating in limited area such as a communication satellite and broadcasting satellite, Particularly, Korea's space industry is in an infant stage, which largely demands government supports. Government support should be in the form of investment or financial contribution, rather than in the form of loan or borrowing. Compared to other advanced countries in space industry, Korea needs more budget and professional research staff. Naturally, for the efficient and systemic space development and for the prevention of overlapping and distraction of power, it is necessary to enact space-related statutes, which would provide dear vision for the Korea space development. Furthermore, the fact that a variety of departments are running their own space development program requires a centralized and single space-industry development system. Prior to discussing how to coordinate or integrate space programs between Agency for Defense Development and the Korea Aerospace Research Institute, it is a prerequisite to establish, namely, "Space Operations Center"in the Air Force, which would determine policy and strategy in operating space forces. For the establishment of "Space Operations Center," policy determinations by the Ministry of National Defense and the Joint Chief of Staff are required. Especially, space surveillance system through using a military surveillance satellite and communication satellite, which would lay foundation for independent defense, shall be established with reference to Japan's space force plan. In order to resolve issues related to MTCR, Air Force would use space-launching vehicle of the Korea Aerospace Research Institute. Moreover, defense budge should be appropriated for using multi-purpose satellite and communication satellite. The Ministry of National Defense needs to appropriate 2.5 trillion won budget for space operations, which amounts to Japan's surveillance satellite operating budges.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.195-204
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• 2020

To help solve the problems of how to set the optimal sawing force and the optimal controller parameters for different sawing conditions, a mathematical model of a proposed sawing system was established according to the principle of sawing force control. The conventional PID control method was then used for further research of the closed-loop control of the sawing force. Finally, through simulation and experimental research, the influence rule of the controller parameters and sawing load on the control performance and the relationships between the sawing width and controller parameters (proportion coefficient) and the sawing force setting value were obtained, from which a system scheme for intelligent sawing control of a band sawing machine was proposed. The research shows that the sawing efficiency of the intelligent sawing system was 18.1 (48%) higher than that of the original sawing system when sawing a grooved section sawing material, which verifies the good control effect of the proposed scheme.

• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.152-163
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• 2013

In this research, we analyse the economic feasibility of a tidal power plant project which can efficiently generate mass, permanent, predictable, and homogeneous electric power. For the economic feasibility analysis, we used the RETScreen that is developed at the CANMET Energy Technology Center in Natural Resources Canada and widely utilized for analysing the economic feasibility and sensitivity of clean energy projects. Results from the feasibility and sensitivity analysis showd that the tidal power plant project in Korea has a enough economic feasibility, and its feasibility increases more as certified emission reductions price and electricity unit price increase. Based on the results from the feasibility study, we can solve the energy problems to be come in near future by constructing the tidal power plants in Korea more aggressively.

• Journal of Korean Society of Archives and Records Management
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• v.19 no.2
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• pp.1-24
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• 2019

In this study, we propose a logical transfer method of records using cloud storage to solve the integrity problem of digital component, which is generated when electronic records are transferred from the electronic record production system to the record management system. This method, which produces electronic records using cloud storage from the production stage and transfers them to the archives, has the following advantages. First, as a record management method, it can be effectively applied in public institutions by utilizing cloud computing technology, which has been the trend recently. Second, unlike the existing method of copying and physically transferring electronic records, the proposed method can reduce various risk factors that may occur in the transfer of electronic records by logically transferring the storage. Third, the method can prevent errors of the digital component according to the physical transfer of the electronic record; hence, the integrity of the electronic record can be guaranteed. Fourth, administrative power and cost that are wasted because of the electronic transfer of electronic records can be reduced.

• The Journal of Korean Association of Computer Education
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• v.21 no.1
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• pp.31-42
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• 2018

Countries around the world are strengthening informatics education to cope with the development of technology that leads to rapid social change. The last step in the capacity to foster through formal education is high school education. The purpose of this study is to examine the competence and level of informatics curriculum for high school students who aim to enter university in terms of testing tools. In order to carry out the research, we analyzed informatics education related test tools for high school students such as Japan, Germany, and USA. The results of the analysis are as follows: First, both the essay type and the short answer type question are included in the test tool as well as the multiple choice question type. Second, we use the real world model as an item and ask whether we can use computing power for practical problem solving ability. Third, the items directly related to the university education are reflected in the items. This study suggests that it has helped to elucidate the features and discussions of the test tool and establish the development direction of the test tool for informatics education.

• The Journal of Korean Association of Computer Education
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• v.9 no.2
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• pp.37-45
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• 2006

Computer education currently executed at middle schools showed problems of system of education curriculum, repetition, and lack of consistent system as a result of analyzing index for information and communication technology curriculum, and related literatures, and most of the education contents have difficulty to nurture logic thinking and problem-solving ability since they are composed mainly of software function learning. Concerning this issue, this study suggests an innovated computer education curriculum with reinforced information ethics field with computer principle, algorithm, and programming, in other words, a corrected and supplemented version of former content system based on computer science guidance cases of ACM computer science curriculum model of USA, computer science curriculum of Florida state, and Unplugged Project(http://www.unplugged.canterbury.ac.nz) judging that introduction of computer science factors are desperate to improve computer education curriculum in middle schools.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.2
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• pp.107-117
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• 2004

If doubtlessly contributes much to agriculture and rural development. The roles can be summarized as; 1. to activate rural areas and to provide more comfortable and safe rural life with equivalent services to those in urban areas, facilitating distance education, tole-medicine, remote public services, remote entertainment etc. 2. To initiate new agricultural and rural business such as e-commerce, real estate business for satellite officies, rural tourism and virtual corporation of small-scale farms. 3. To support policy-making and evaluation on optimal farm production, disaster management, effective agro-environmental resource management etc., providing tools such as GIS. 4. To improve farm management and farming technologies by efficient farm management, risk management, effective information or knowledge transfer etc., realizing competitive and sustainable farming with safe products. 5. To provide systems and tools to secure food traceability and reliability that has been an emerging issue concerning farm products since serious contamination such as BSE and chicken flu was detected. 6. To take an important and key role for industrialization of farming or lam business enterprise, combining the above roles.

• Journal of dental hygiene science
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• v.17 no.4
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• pp.368-374
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• 2017

The purpose of this study was to evaluate community dental hygiene practice education, by verifying its effect after applying project-based learning in improving the practical and social skills of learners. A 15-week project-based community dental hygiene practice course was held for 27 senior students, who took community dental hygiene practice course in the Department of Dental Hygiene, Gangneung-Wonju National University. Twenty-seven students were composed of 4 teams. Each team selected a target group for four workplaces for adult workers to apply the oral health promotion project. The project was then planned and conducted based on a survey on the health problems confronting each group, and an evaluation was carried out after 4 weeks. From the results obtained in comparing confidence in problem solving ability, project value, teamwork competency, and community dental hygienist competence before and after course, the improvement in project value and teamwork competence scores was not statistically significant, but all four areas showed positive results. After analyzing the project actuality, learning outcomes, and project satisfaction after course results, the actuality of the project was 19.30 points, the learning achievement was 45.19 points, and the satisfaction was 19.19 points, demonstrating that the aim of achieving actual performance competence and a learning performance exceeding expectations was accomplished. After conducting an interview survey with 8 students, it was found that they had learned social skills involving problem-solving abilities and confidence, and teamwork competence such as cooperation, role responsibility, creative thinking ability, and communication skills. Community dental hygienists should be able to acquire learner-level practical skills and social skills in the community dental hygiene and practical courses, according to their competencies and job needs. It is necessary to develop a project?based systematic learning module to enable the community dental hygiene practice to operate as a subject closely related to fields in other dental hygiene departments.