• Journal of Educational Research in Mathematics
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• 제24권4호
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• pp.607-622
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• 2014

The purpose of this paper is that it analyzes the historical development of the concept of trigonometric functions and discuss some didactical implications. The results of the study are as follows. First, the concept of trigonometric functions is developed from line segments measuring ratios to numbers representing the ratios. Geometry, arithmetic, algebra and analysis has been integrated in this process. Secondly, as a result of developing from practical calculation to theoretical function, periodicity is formalized, but 'trigonometry' is overlooked. Third, it must be taught trigonometry relationally and structurally by the principle of similarity. Fourth, the conceptual generalization of trigonometric functions must be recognized as epistemological obstacle, and it should be improved to emphasize the integration revealed in history. The results of these studies provide some useful suggestions to teaching and learning of trigonometry.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제23권8호
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• pp.57-66
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• 2009

The conventional fixed gain PI controller is very sensitive to step change of command speed, parameter variation and load disturbances. The precise speed control of interior permanent magnet synchronous motor(IPMSM) drive becomes a complex issue due to nonlinear coupling among its winding currents and the rotor speed as well as the nonlinear electromagnetic developed torque. Therefore, there exists a need to tune the PI controller parameters on-line to ensure optimum drive performance over a wide range of operating conditions. This paper proposes hybrid intelligent-PI(HIPI) controller of IPMSM drive using adaptive learning mechanism(ALM) and fuzzy neural network(FNN). The proposed controller is developed to ensure accurate speed control of IPMSM drive under system disturbances and estimation of speed using artificial neural network(ANN) controller. The PI controller parameters are optimized by ALM-FNN at all possible operating condition in a closed loop vector control scheme, The validity of the proposed controller is verified by results at different dynamic operating conditions.

• Journal of Family Resource Management and Policy Review
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• 제21권1호
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• pp.89-111
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• 2017

The purpose of this study was to examine the phenomenon of social participation among female baby boomers. The key research questions were asked in what kind of activities do female baby boomers engage as social participation? The in-depth interview was used with 11 female baby boomers who were born between 1955 to 1963. The interview text were analyzed by the qualitative study method. The findings are as follows. First, the most common type of social participation was having hobbies and leisure activities, and the other were participating in religious activities, learning activities, volunteer activities and on-line club activities. Second, social participation gave them meanings such as joy, satisfaction, and experiences of seeing the new world as well as opportunities to make up low sense of self-esteem formed in their young age. Third, they were considering it was time to change their social participation. The cases who were actively engaging in social participation considered old age as 'the process of reducing social participation'. Some other cases considered to 'share hobbies with spouse', and to 'achieve new goals and dreams'. The results showed that female baby boomers started their social participation in their middle ages when they became free from their children's education. The level of the involvement in social participation was reduced in their old age. Surprisingly, some interviewees planned to accomplish their dreams and goals that they haven't achieved yet. These differences among the cases could be attributed to the individual characteristics such as personality, birth order, economic and educational background, and to the social relationship.

• Journal of Korean Library and Information Science Society
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• 제43권2호
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• pp.293-315
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• 2012

Recently there have been an increase in number of new library buildings and its users due to the demand of lifelong learning and cultural experiences of the local community and also the extension to their opening hours. At the same time there have been a growing number of problem users in local libraries. This seems closely associated with an increase in number of unemployment rates and their mental health issue. This causes a great challenge to the local libraries. in particular, to the front-line librarians. If these challenges are not dealt appropriately at all levels within the library organization the overall quality of services is likely to degrade leaving the general users dissatisfied and the staff adversely affected. Therefore in this study we propose a charter of library service and a library code of conduct to meet the aforementioned challenges and enhance the overall quality of library services.

• School Mathematics
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• 제9권1호
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• pp.45-64
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• 2007

The primary purposes of this study were to investigate how sixth graders would react to the types of tasks with regard to the comprehension of graphs and what differences might be among the kinds of graphs, and to raise issues about instructional methods of graphs. A descriptive study through pencil-and-paper tests was conducted. The tests consisted of 48 questions with 4 types of tasks (reading the data, reading between the data, reading beyond the data, and understanding the situations) and 6 kinds of graphs. The conclusions drawn from the results obtained in this study were as follows: First, it is necessary to foster the ability of interpreting the data and understanding the situation in graphs as well as that of reading the data and finding out the relationships in the data. Second, it is informative for teachers to know students' difficulties and thinking processes. Third, in order to develop understanding of graphs, it is important that students solve different types of tasks beyond simple question-answer tasks. Fourth, teachers need to pay attention to teach fundamental factors such as reading the data with regard to line graphs and stem-and-leaf plots Finally, graph type and task type interact to determine graph-comprehension performance. Therefore, both learning all kinds of graphs and being familiar with multiple types of tasks are important.

• Journal of Internet Computing and Services
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• 제10권5호
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• pp.183-194
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• 2009

In this paper, we propose a new method for detecting objectionable images with an active shape model. Our method first learns the shape of breast lines through principle component analysis and alignment as well as the distribution of intensity values of corresponding landmarks, and then extracts breast lines with the learned shape and intensity distribution. To accurately select the initial position of active shape model, we obtain parameters on scale, rotation, and translation. After positioning the initial location of active shape model using scale and rotation information, iterative searches are performed. We can identify adult images by calculating the average of the distance between each landmark and a candidate breast line. The experiment results show that the proposed method can detect adult images effectively by comparing various results.

• The Journal of Fisheries Business Administration
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• 제47권3호
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• pp.53-69
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• 2016

The purpose of this study is to explore the ecosystem service and benefit indicators of natural seaweed beds. Ecosystems of natural seaweed beds provide a wide range of services and benefits to human society including provisioning services, regulating services, supporting services, and cultural services. Indicators for each of the ecosystem services are chosen by marine plants ecologists and as follows. Ecosystem indicators of natural seaweed beds for provisioning services are well-being food(amount of seaweed harvested/amount of fish landed, fish biomass, area of natural seaweed beds, the number of species, contribution to the second production), raw materials(amount of biomass by breed, amount of aquaculture feed), genetic resources(amount of genetic material extracted, amount of genetic material contained by age and habitat), and medicinal resources(amount of medicinal material extracted). Ecosystem indicators of natural seaweed beds for regulating services are air purification(amount of fine dust/NOx or $SO_2$ captured), climate regulation(amount of $CO_2$ sequestered), waste treatment(amount of N, P stored, biochemical degradation capacity COD), and costal erosion prevention(length and change of natural coast line, amount of sediment prevented). Ecosystem indicators of natural seaweed beds for supporting services are lifecycle and maintenance(primary production, contribution to the second production) and gene pool protection(amount of compositional factors in ecosystem, introduced species). Ecosystem indicators of natural seaweed beds for cultural services are recreation and tourism(the number of visits of an area) and information for cognitive development(amount of time spent in education, research and individual learning about ecosystem of natural seaweed beds).

• Korean Journal of Biological Psychiatry
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• 제21권4호
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• pp.118-127
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• 2014

Along with language, socialization is a unique feature of the human being. There is a continuous debate regarding whether the development of socialization is innate, and conducted by the environment in the growing process, or the result of the interaction of both aspects. If socialization is the result of the interaction with the environment or is an acquired developmental process, the following question rises. "Is there a 'critical period' for the development of socialization?" Although there are a huge number of studies seeking for treatment and solutions for developmental delay or deficits of socialization, it is very complicated question to answer. Historical figures such as 'Hugh Blair' of Borgue in England, and 'the wild boy of Aveyron' in France, seem to have innate socialization deficits. Nowadays patients with non-verbal learning disorder, social communication disorder, or autism spectrum disorder seem to have genetic defects. On the other hand, Harry Harlow's monkey experiments, hikikomori of Japan, Romanian orphans and patients with reactive attachment disorder seem to display social deficits due to environmental factors. However, it is not easy to clearly draw a line between innate or acquired factors. Therefore, rather than subdividing the diseases for etiological and pathophysiological approach to heterogenous groups with the common denominator of social deficit, and for the research of pathophysiology and treatment development, the authors suggest a comprehensive concept of "social dysfunction spectrum."

• Journal of the Korea Society of Computer and Information
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• 제16권5호
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• pp.135-145
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• 2011

These days, the research of a sensor data management system for USN based real-time monitoring application is active thanks to the development and diffusion of sensor technology. The sensor data is rapidly changeable, continuous and massive row level data. However, end user is only interested in high level data. So, it is essential to effectively process the row level data which is changeable, continuous and massive. In this paper, we propose a sensor data management system with multi-analytical query function using OLAP and anomaly detection function using learning based classifier. In the experimental section, we show that our system is valid through the some experimental scenarios. For the this, we use a sensor data generator implemented by ourselves.

• The Journal of Bigdata
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• 제5권1호
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• pp.181-188
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• 2020

As the size of the airport terminal grows in line with the rapid growth of aviation passengers, the advanced baggage handling system that combines various data technologies has become an essential element in order to handle the baggage carried by passengers swiftly and accurately. Therefore, this study introduces the method of analyzing the baggage handling capacity of domestic airports through the latest data analysis methodology from the process point of view to advance the operation of the airport BHS and the main points based on event log data. By presenting an accurate load prediction method, it can lead to advanced BHS operation strategies in the future, such as the preemptive arrangement of resources and optimization of flight-carrousel scheduling. The data used in the analysis utilized the APIs that can be obtained by searching for "Korea Airports Corporation" in the public data portal. As a result of applying the method to the domestic airport BHS simulation model, it was possible to confirm a high level of predictive performance.