• 한국기계가공학회지
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• 제20권9호
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• pp.70-75
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• 2021

We developed a platform that was capable of autonomous steering in a furrow environment. It was developed to autonomously control steering by recognizing the furrow using a laser distance, three-axis tilt, and temperature sensor. The performance evaluation indicated that the autonomous steering success rate was 99.17%, and it was possible to climb up to 5° on the slope. The usage time was approximately 40 h, and the maximum speed was 6.7 km/h.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.725-727
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• 2006

The development of GIS and Location-Based Services requires a high-level database that will be able to allow real-time access to moving objects for spatial and temporal operations. MODB.MM is able to meet these requirements quite adequately, providing operations with the abilities of acquiring, storing, and querying large-scale moving objects. It enables a dynamic and diverse query mechanism, including searches by region, trajectory, and temporal location of a large number of moving objects that may change their locations with time variation. Furthermore, MODB.MM is designed to allow for performance upon main memory and the system supports the migration on out-of-date data from main memory to disk. We define the particular query for truncation of moving objects data and design two migration methods so as to operate the main memory moving objects database system and file-based location storage system with.

• Journal of Communications and Networks
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• 제3권4호
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• pp.342-350
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• 2001

The Internet routing instability, or the rapid fluctuation of network reachability information, is an important problem currently facing the Internet engineering community. High levels of network instability can lead to packet loss, increased network latency, and delayed routing convergence. At the extreme, high levels of routing instability can lead to the loss of internal connectivity in wide-area networks. In this paper, we investigate the variation of domain degree and domain count of the inter-domain network over time by using linear regression model in order to analyze the topology variation of inter-domain network. We Also propose an efficient policy management model to reduce the instability in the inter-domain routing system. The proposed model can be used to identify whether a routing policy is adequate to reduce convergence time that is required to return to a normal state when BGP routing instability happens. Experimental analysis shows that the proposed model can be used to set up routing policy in domains for the purpose of minimizing the effects and the propagation of BGP routing instability.

• 한국융합학회논문지
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• 제9권7호
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• pp.293-300
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• 2018

청소년기 운동선수들에게 다양한 진로 선택의 기회를 실현시켜주기 위해서는 가장 먼저 학생 자신의 적성에 맞는 직업을 선택할 수 있도록 도움을 주는 것이다. 청소년기 운동선수들은 일반적인 청소년들과 달리 다양한 진로를 선택하고 이를 실현하는데 사용될 수 있는 절대적인 시간이 부족한 것이 현실이다. 따라서 청소년기 운동선수들에게는 자신의 적성에 맞는 직업군 별로 차별화되고 특성화된 융합적 학습자료가 필요한 것이다. 이들 직업군 별로 특성화된 학습자료는 가장 적은 시간의 투입으로 가장 큰 교육효과를 나타낼 수 있는 방법이기에 청소년기 운동선수들의 다양한 진로 선택의 기회를 실현시켜주기 위해서라도 꼭 필요한 정보로써의 활용 가치가 높다고 할 수 있다.

• 한국수소및신에너지학회논문집
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• 제27권3호
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• pp.306-310
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• 2016

In Na-base Battery for ESS, ${\alpha}-Al_2O_3$ and metal bonding was used to prevent direct reaction between electrolyte and electrode. The hard metal was metalized at $1600^{\circ}C$ in a flowing hydrogen gas for high bonding strength. In this study, instead of hard metal metalizing, Ni was plated on ${\alpha}-Al_2O_3$ by electroless Ni plating technique and then bonded with metal. To enhance the bonding strength, surface of ${\alpha}-Al_2O_3$ was treated with $H_3PO_4$. The effects of strength and leakage of joining as a function of acid treatment time on ${\alpha}-Al_2O_3$ are described.

• International journal of advanced smart convergence
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• 제8권1호
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• pp.65-74
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• 2019

3D file formats typically include OBJ (Wavefront file format), STL (STereoLithography), and FBX (Filmbox). Each format has limitations depending on its configuration and usage, and supported formats are different depending on the software application. glTF helps uniform integration of 3D file formats and allows for more efficient transmission of large 3D geometry files by organizing them in a binary format. This paper presents explanation on OBJ, FBX, and STL which are major examples of existing 3D file formats. It also explains the concept and characteristics of glTF and compares its performance with other 3D file formats on the web. The loading time and packets of each 3D file format are measured according to the web browser environment by means of Google Chrome, Firefox and Microsoft Edge. Experimental results show that glTF is the most efficient and that it exhibits the best performance. As to STL, relatively excessive traffic was observed. This study is expected to contribute to reducing rendering time on the web as 3D file formats are used.

• 한국멀티미디어학회논문지
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• 제25권2호
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• pp.257-268
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• 2022

When there is a missing value in the raw data, if ignore the missing values and proceed with the analysis, the accuracy decrease due to the decrease in the number of sample. The method of imputation and analyzing patterns and significant values can compensate for the problem of lower analysis quality and analysis accuracy as a result of bias rather than simply removing missing values. In this study, we proposed to study irregular data patterns and missing processing methods of data using machine learning techniques for the study of correction of missing values. we would like to propose a plan to replace the missing with data from a similar past point in time by finding the situation at the time when the missing data occurred. Unlike previous studies, data correction techniques present new algorithms using DNN and KNN-MLE techniques. As a result of the performance evaluation, the ANAE measurement value compared to the existing missing section correction algorithm confirmed a performance improvement of about 0.041 to 0.321.

• 로봇학회논문지
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• 제18권2호
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• pp.189-196
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• 2023

An abdominal brace is a recommended treatment for patients with lumbar spinal disorders. However, due to the nature of the static brace, it uniformly compresses the lumbar region, which can weaken the lumbar muscles or create a psychological dependence that worsens the condition of the spine when worn for an extended period of time. Due to these issues, doctors limit the wearing time when prescribing it to patients. In this paper, we propose a device that can dynamically provide abdominal pressure and support according to the lumbar motion. The proposed device is a wearable robot in the form of a brace, with actuators and a driving unit mounted on the brace. To enhance wearability and reduce the weight of the device, worm gears actuator and a multi-pulley mechanism were adopted. Based on the spinal motion of the wearer measured by the Inertia measurement unit sensors, the drives wire by driving pulley, which provide tension to the multi-pulley mechanism on both sides, dynamically tightening or loosening the device. Finally, the device can dynamically provide abdominal pressure and support. We describe the hardware and system configuration of the device and demonstrate its potential through basic control experiments.

• 한국ITS학회 논문지
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• 제22권6호
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• pp.246-263
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• 2023

제어권 전환 안정화 시간(Stabilization time of take-over)은 제어권 전환 이후 운전이 안정화 될 때까지의 시간을 의미한다. 자율주행시스템(autonomated driving system)의 제어권 전환 요청(take-over request) 직후, 운전자는 도로의 주행환경을 인지하고 수동운전을 수행해야하기 때문에 주행환경과 제어권 전환 안정화 시간의 관계를 명확히 규명하는 것은 매우 중요하다. 반면, 제어권 전환 안정화 시간에 대해 특정하여 수행된 기존 연구는 드물었으며, 주행환경을 고려한 연구도 부족한 실정이다. 이 점에 기인하여 본 연구는 드라이빙 시뮬레이터를 활용한 제어권 전환 실험을 수행하고, 실험 결과를 선형혼합모형(linear mixed model)을 통해 분석하여 제어권 전환 안정화 시간에 영향을 미치는 주행환경 요소를 정량적으로 도출하였으며, 각 영향요인에 따른 제어권 전환 안정화 계수를 도출하였다.

• 한국융합학회논문지
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• 제9권4호
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• pp.23-29
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• 2018

건설현장에서 흔히 발생하는 안전관리 문제점 중 시정조치 지연으로 인해 발생하는 재해율을 낮추기 위해, 기존의 시스템 중 점검 후 시정조치를 할 때까지 발생하는 시간을 단축하기 위하여 사전에 사고유형 데이터베이스를 구축하고 점검시 유사도 검사를 이용하여 점검자에게 문제점을 실시간으로 알려주어 현장에서 바로 시정조치를 수행할 수 있는 시스템을 모델링하여, 안전사고에 보다 적극적으로 대처할 수 있는 시스템을 연구하였다. 연구 결과 90 %이상의 개방 효과와 60 %이상의 안전사고 감소율이 있음을 알 수 있었다. 이 시스템을 기반으로 음성 인식과 딥러닝을 결합하여 보다 효과적인 시스템을 지속적으로 연구 할 것이다.