• Research in Mathematical Education
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• v.16 no.4
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• pp.217-232
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• 2012

While many studies on early algebra have been conducted, there have been only a few studies on the operation sense as the fundamental element of algebraic thinking, especially the fraction operation sense. This study explored the dimensions of fraction operation sense and then investigated students' fraction operation sense. A total of 183 of sixth graders were surveyed and 5 students who showed high operation sense were clinically interviewed in order to analyze their algebraic thinking in detail. The results showed that students had a tendency to use direct calculation or employ inappropriate operation sense rather than to use the structure of operation or the relation between operations on the basis of algebraic thinking. This study implies that explicit instruction on early algebra is necessary from the elementary school years.

• Nuclear Engineering and Technology
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• v.41 no.3
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• pp.237-246
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• 2009

Digitalization of not only non-safety but also safety-grade I &C systems with full computerized Main Control Room (MCR) is the recent trend of I&C systems of nuclear power plants (NPP) around the world, while plant maintenance has been shifting from traditional time based maintenance to condition based maintenance. In order to cope with the new trend of operation and maintenance in NPP, a concept of online distributed diagnostic system for both plant operation and maintenance has been proposed in order to further improve both the plant efficiency and the work environment of plant operation staff members by organizational learning. In this respect, the research subjects of human machine interface (HMI) for the online distributed diagnostic system are also discussed for supporting the plant personnel at both MCR and local working places in the plant by the application of advanced ICT (Information and Communication Technologies).

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.5
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• pp.67-76
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• 2003

The principal operation rule of irrigation reservoir is to accelerate the water use and supply water actively when water is sufficient, and to restrict water use and supply water deficiently in order not to stop the irrigation activity when water is scarce. In drought seasons. water should be saved in order to keep the reservoir not to be dried up during the irrigation season. It is important to know how much water should be saved, depending on the rice-growing season and water storage volume. For the drought control of irrigation reservoirs. the rotational irrigation scheduling in paddy with the operation rule curve developed in this study could be utilized as a software program to install TM/TC system for irrigation water supply by automation facilities.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.4
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• pp.240-250
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• 1988

This pc-vision system digitizes/displays 512*512*8 bit pixel image in real time and is capable of the various image processing. This system provides a versatile solution to those users pursuing high performance image processing system compatible with the VME bus, and is general purpose imaging system giving the optimal efficiency for machine vision, medical use and various task. In this paper, Image processing technique has classified image enhancement and image analysis in order to design and implement the pc-vision system. In order to improve processing speed, This system unilizing ROI processing performs point operation, local operation and global operation as well as common arithmetic/logic operation in real time.

• Journal of Navigation and Port Research
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• v.31 no.7
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• pp.605-611
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• 2007

In order to become a mega hub port, major ports all over the world are making every effort to enhance their productivity through efficiency of internal operation. Accordingly, in order to enhance the competitiveness of a container terminal, an automated container terminal is considered as the best alternative. An automated container terminal is using such automated handling equipment as AGV(Automated Guided Vehicles) and ATC(Automated Transfer Crane). The efficient equipment operation plays a critical role in enhancing the productivity of an automated container terminal. In an automated container terminal, the most important equipments are AGV and ATC. Each block of containers with a vertical layout is generally operating two ATCs. The two ATCs can be crossed or not at each block. In the case of operating crossover ATC, it has an advantage of high flexibility that ATC work is possible at both TP(Transfer Point) of each block. But it has also a disadvantage that the yard has to be operated at a low storage level of containers in the terminal yard. Recently, for automated container terminals, which are being prepared for opening in Korea, they plan to use uncrossed twin ATC in order to make the storage level of their yards high at a low cost. Therefore, studies have to be made in order to increase the efficiency of twin ATC system based on the flexibility that the crossover ATC system has. This research aims to suggest an operation strategy to improve efficiency of twin ATC at each storage block in a yard.

• Hip & pelvis
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• v.34 no.4
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• pp.262-268
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• 2022

A fracture of the affected extremity in patients with Klippel-Trenaunay-Weber syndrome can be fatal due to massive bleeding and show poor results. A 42-year-old male presented with an old fracture of the right femoral shaft with metal failure. We planned an operation to remove the previously fixed plate and to perform re-fixation using an intra-medullary nail. Preoperative angiography was performed and the arteriovenous malformations were embolized in order to reduce the risk of bleeding. After angiography, the previously fixed plate was removed. After the operation, a second angiography was performed immediately and the venous malformation was embolized. One week after the first operation, a second operation was performed in order to reduce the fracture and to perform re-fixation using an intramedullary nail. The patient is being followed without major complication over a period of seven years after surgery. We recommend careful planning of preoperative and postoperative angiography and embolization in order to reduce the risk of bleeding in patients with Klippel-Trenaunay-Weber syndrome.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.35-41
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• 2011

The national police agency has executed the project for the advancement of traffic control and operation systems in order to mitigate chronic traffic problems and to meet the global standards regarding the traffic control and operation systems. This study effort was initiated to evaluate the effects of various policies proposed for the advancement of traffic control and operation systems. The evaluation results indicated that the policies proposed for the advancement of traffic control and operation systems showed apparent and positive effects in terms of transportation mobility and safety. However, there have been many difficulties to overcome in order to settle down the policies proposed for the advancement of traffic control and operation systems as smooth as possible. For example, the violation of intersection passing method has been increased after the implementation of the advancement of traffic control and operation systems in majority of evaluation sites. In addition, lacks of awareness as well as improper operations of the advancement of traffic control and operation systems have caused drivers' confusions, which generated more traffic congestion and risks. Currently, the policies for the advancement of traffic control and operation systems focused on the improvements of traffic signal operations, including leading through movements and permissive left-turns. However, synergy effects may be expected if all of the policies including the improvements of traffic signal operations are executed together.

• Journal of Industrial Technology
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• v.29 no.B
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• pp.221-228
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• 2009

For a stable supply of electric power, periodical inspection of the electric facilities and repair of the distribution lines are required. In case of any unexpected accidents, looped operation among distribution lines may be necessary in order to supply electricity through the sound lines, separating the faulted lines. As a result of this study, it was found that normal looped operation became impossible when phase difference of the looped distribution lines is more than 3 degrees compared with the voltage supply of the distribution lines. Therefore, for a stable supply of electric power to Chuncheon, it is judged to be desirable that looped operation of the distribution lines coming from the same substation M. Tr Bank shall be performed in principle and in case of looped operation with the substation of different system, looped operation among the lines shall be performed after voltage regulation of the substation M. Tr Bank, maintaining similar voltages and load supply volume in order to avoid phase difference through checking the operation conditions of each substation M. Tr Banks. And when looped operation among the distribution lines is scheduled, voltage regulation schedule has been established so far by calculating maximum supply volume through the transformer of the substation and the maximum load volume through the distribution lines but in the future, looped operation of the distribution lines shall be carried out by removing voltage difference with regulating tap or load of the surrounding transformers, with giving prior notice to the substation operators.

• Journal of Information Technology Services
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• v.18 no.4
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• pp.67-82
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• 2019

The purpose of this study is to improve the calculation method of the software operation pricing proposed by the software business price calculation guide from 'input manpower method' to 'rate calculation method'. The software operation pricing of the input manpower method is not objectively calculated in the domestic IT outsourcing situation where the statistical data based on the activity based estimating is insufficient and it is decided by agreement between the owner and the client. In addition, there was no standard for adjusting the productivity according to the characteristics of the operation service. In order to improve this, an operational correction factor item that can affect the software operation productivity was selected based on foreign and domestic standards, and it was confirmed through the first questionnaire to IT operation managers. In order to determine the level of difficulty of the fixed operational correction factors, the operational correction factor using AHP technique was confirmed through a second questionnaire for pairwise comparison. The operational difficulty calculation table was developed with reference to COCOMO and ITIL standards. Finally, we propose a new pricing scheme that reflects the operating rate. Regression analysis was carried out by collecting the data of the domestic public institutions on the estimated cost and the actual cost calculated from the new rate method software operation pricing. The results of the regression analysis show that the estimated cost and the actual cost are related to each other. Mean magnitude of relative error(MMRE) and PRED[25] analysis were added for accuracy analysis. MMRE and PRED also showed satisfactory results, confirming the possibility of replacing the rate method software operation pricing.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.185-196
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• 2012

Information system operation principles were recently established in order to provide high quality service and efficient operation audit of IT outsourcing. Operation managements are done based on these principles. Therefore, information operating management process, which refers to itself, is established. Information system operation audit requires a constant audit regularly, which is different from construction/development audit that is done only once. As operating management process changes, operation audit guidelines should be updated and improved. Therefore, this paper proposes IT outsourcing operation audit model with IT outsourcing achievement management as a focus. IT service domain was referred in order to propose information system operation audit model and check lists, which are based on IT outsourcing operation managements such as planning, making strategies, contract, service, and management. The deduced audit model and check lists verified suitability of the proposed model by experts' survey.