• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.774-778
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• 2008

The inaccuracy of inertial sensors used in low cost IMU's limits the usage to ARS, at best. Sensor fusion technologies are widely used to overcome this problem. GPS is the most popular secondary sensor, but GPS alone cannot fully compensate the IMU errors in the initial alignment process and rectilinear flights. This paper presents a new concept of aiding the low cost IMU with the sun line of sight vector. The simulation and experimental results in this paper proves that aiding of INS/GPS with the sun line of sight vector increases the observability and improves accuracy remarkably.

• The Journal of Korean Association of Computer Education
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• v.11 no.5
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• pp.47-55
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• 2008

The Internet is one of the most infrastructure for information technology in school education. Providing the Internet with a proper bandwidth is an important element for efficient school education for information technology, especially because several instructional models based on new Internet technologies are under development. To support these instructional models, it is important for the schools to provide the proper Internet bandwidth wherever necessary. In this paper, the amount and pattern of internet usage in school were analyzed. Based on this analysis, we propose how to figure out a proper bandwidth for a different ladder of schools.

• Progress in Superconductivity and Cryogenics
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• v.6 no.4
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• pp.51-54
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• 2004

A 1 MV A single phase high temperature superconducting (HTS) transformer was manufactured. In order to reduce AC loss generated in the HTS winding, winding was concentrically arranged. Operation temperature is set at 65K to increase the critical current and reduce the amount of HTS tape usage and the volume. The cryogenic system which consists of main cryostat with the windings and secondary cryostat with 2 GM coolers and cryopump on top and heat exchanger inside is also designed and the cooling performance is simulated with Fluent. Temperature distribution of the windings is investigated whether the windings are kept under designed operation temperature.

• East Asian mathematical journal
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• v.26 no.2
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• pp.165-177
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• 2010

The purpose of this study is to review previous studies regarding the relationship between graphing calculators usage and teaching and learning school mathematics and to suggest practical implications for further research in mathematics education. Through reviewing the total of 21 studies five subsections are divided in order to gain the answers to the research questions. The results of this study are as follows: students typically used graphing calculators in drawing graphs of functions, and they used graphing calculators as a tool for calculations, transformations, data collection and analysis, visualization, and checking. The implications for further research are suggested corresponding to these results.

• Journal of the Korean Institute of Educational Facilities
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• v.23 no.5
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• pp.3-10
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• 2016

The purpose of this study is to provide a basis for planning of school foodservice facilities to operate with hygiene and efficiency corresponding a decrease of the number of students. This study analyzes the composition of space for foodservice facilities categorizing by the functions which are preparation area, cooking area, cleaning area, storage, and worker's room on elementary, middle and high school in Seoul Metropolitan city since 2009 that the Seoul School Health Promotion Center published a manual for school foodservice facilities. The calculation can be a basis for school planners and the general schools to use available area in each school and can manage the school usage plan appropriately. The number of students in each school has been regarded as the space planning element, but the number of students would considered with using the specific area and time.

• Ecology and Resilient Infrastructure
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• v.5 no.1
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• pp.1-10
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• 2018

We examined the effect of simultaneous application of phosphorus (P) and iron (Fe) on the phytotoxicity of lettuce in arsenic (As) contaminated soil using response surface methodology (RSM). To stabilize As and supply nutrient into soil, Fe and P were treated, respectively. Water soluble As and P was decreased by Fe application but increased by P application. Through phytotoxicity test, the result showed that only the addition of P affected lettuce root elongation even though both P and Fe were added. The correlation coefficients between root elongation and other indices indicated that the As content in the roots seemed to be the main reason that root growth was impeded. We could verify that the former result was not a passing phenomenon and Fe was necessarily needed to protect secondary pollution by exclusive usage of P fertilizer.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.435-436
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• 2014

소프트웨어의 불법 복제 및 인증을 거치지 않은 부정 사용 등이 큰 문제가 되고 있다. 소프트웨어 부정 사용을 막기 위해 usb 인증, 시리얼 키 인증, 서버접속을 통한 인증 등 다양한 방법들이 존재해 왔다. 그러나 이러한 기술들의 우회 방법들이 상당수 공개된 실정이다. 본 연구에서는 보다 강화된 인터넷 인증 기반의 불법 사용 방지 기술을 제안하고자 한다. 뿐만 아니라 소프트웨어를 사용해 만들어 낸 2차 창작물 또한 보호하는 방법을 제시하고자 한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.3
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• pp.265-274
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• 2022

This paper proposes a machine learning-based screening algorithm to build the retired battery pack of the energy storage system. The proposed algorithm creates the dataset of various performance parameters of the retired battery, and this dataset is preprocessed through a principal component analysis to reduce the overfitting problem. The retried batteries with a large deviation are excluded in the dataset through a density-based spatial clustering of applications with noise, and the K-means clustering method is formulated to select the group of the retired batteries to satisfy the deviation requirement conditions. The performance of the proposed algorithm is verified based on NASA and Oxford datasets.

• ETRI Journal
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• v.44 no.2
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• pp.244-259
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• 2022

Bicycle- or bike-sharing systems (BSSs) have received increasing attention as a secondary transportation mode due to their advantages, for example, accessibility, prevention of air pollution, and health promotion. However, in BSSs, due to bias in bike demands, the bike rebalancing problem should be solved. Various methods have been proposed to solve this problem; however, it is difficult to apply such methods to small cities because bike demand is sparse, and there are many practical issues to solve. Thus, we propose a demand prediction model using multiple classifiers, time grouping, categorization, weather analysis, and station correlation information. In addition, we analyze real-world relocation data by relocation managers and propose a relocation algorithm based on the analytical results to solve the bike rebalancing problem. The proposed system is compared experimentally with the results obtained by the real relocation managers.

• Applied Chemistry
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• v.16 no.1
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• pp.73-76
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• 2012

Due to the developments of communications equipment and electronic devices, lithium ion secondary battery usage is growing. Along with demand increasing, the amount of scrap has been steadily increasing. In this study, method of cobalt recovery using organic eco-friendly is proposed. Sulfuric acid, Malic acid, Citric acid at reflux device had good cobalt leaching efficiency. And Sulfuric acid, Malic acid at the autoclave increased cobalt leaching efficiency.