• The KIPS Transactions:PartD
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• v.16D no.2
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• pp.237-248
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• 2009

Recently, based on dynamic location or mobility of moving object, many researches on pattern mining methods actively progress to extract more available patterns from various moving patterns for development of location based services. The performance of moving pattern mining depend on how analyze and process the huge set of spatio-temporal data. Some of traditional spatio-temporal pattern mining methods[1-6,8-11]have proposed to solve these problem, but they did not solve properly to reduce mining execution time and minimize required memory space. Therefore, in this paper, we propose new spatio-temporal pattern mining method which extract the sequential and periodic frequent moving patterns efficiently from the huge set of spatio-temporal moving data. The proposed method reduces mining execution time of $83%{\sim}93%$ rate on frequent moving patterns mining using the moving sequence tree which generated from historical data of moving objects based on hash tree. And also, for minimizing the required memory space, it generalize the detained historical data including spatio-temporal attributes into the real world scope of space and time using spatio-temporal concept hierarchy.

• Journal of the Korean Institute of Intelligent Systems
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• v.6 no.3
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• pp.81-88
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• 1996

Cluster analysis is based on partitioning a collection of data points into a number of clusters, where the data points in side a cluster have a certain degree of similarity and it is a fundamental process of data analysis. So, it has been playing an important role in solving many problems in pattern recognition and image processing. For these many clustering algorithms depending on distance criteria have been developed and fuzzy set theory has been introduced to reflect the description of real data, where boundaries might be fuzzy. If fuzzy cluster analysis is tomake a significant contribution to engineering applications, much more attention must be paid to fundamental questions of cluster validity problem which is how well it has identified the structure that is present in the data. Several validity functionals such as partition coefficient, claasification entropy and proportion exponent, have been used for measuring validity mathematically. But the issue of cluster validity involves complex aspects, it is difficult to measure it with one measuring function as the conventional study. In this paper, we propose four performance indices and the way to measure the quality of clustering formed by given learning strategy.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.7
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• pp.263-270
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• 2021

Reinforcement learning(RL) is the method to find an optimal policy through training. and it is one of popular methods for solving lifesaving and disaster response problems effectively. However, the conventional reinforcement learning method for disaster response utilizes either simple environment such as. grid and graph or a self-developed environment that are hard to verify the practical effectiveness. In this paper, we propose the design of a disaster response RL environment which utilizes the detailed property information of the disaster simulation in order to utilize the reinforcement learning method in the real world. For the RL environment, we design and build the reinforcement learning communication as well as the interface between the RL agent and the disaster simulation. Also, we apply the dimension reduction method for converting non-image feature vectors into image format which is effectively utilized with convolution layer to utilize the high-dimensional and detailed property of the disaster simulation. To verify the effectiveness of our proposed method, we conducted empirical evaluations and it shows that our proposed method outperformed conventional methods in the building fire damage.

• The Journal of the Convergence on Culture Technology
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• v.5 no.2
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• pp.345-353
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• 2019

The Video See-through HMD(VSHMD) captures real-world view through a camera set mounted in front of the HMD. The VSHMD outputs this visual information in real time through the display in the HMD, which technique can be used as mixed reality, augmented reality, and virtual reality device. Recently, there is growing interest in VSHMD due to the rapid development of camera and display technology. However, VSHMD is still not free from many technical huddles and human factor issues. This paper summarizes the VSHMD related researches so far, presents the major issues to be solved in advance, and suggests design considerations that should be beneficial to VSHMD development, focused on the human factors, that presents solutions to effectively overcome the limitations of VSHMD functionalities in current.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.8
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• pp.1103-1110
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• 2022

Due to the rapid development of AI-related industries, countless edge devices are working in the real world. Since data generated within the smart space consisted of these devices is beyond imagination, it is becoming increasingly difficult for edge devices to process. To solve this issue, EdgeCPS has appeared. EdgeCPS is a technology to support harmonious execution of various application services including AI applications through interworking between edge devices and edge servers, and augmenting resources/functions. Therefore, we propose a knowledge-sharing graph-based componentized AI application support system applicable to the EdgeCPS platform. The graph is designed to effectively store information which are essential elements for creating AI applications. In order to easily change resource/function augmentation under the support of the EdgeCPS platform, AI applications are operated as components. The application support system is linked with the knowledge graph so that users can easily create and test applications, and visualizes the execution aspect of the application to users as a pipeline.

• Journal of Science Education
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• v.46 no.1
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• pp.109-120
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• 2022

Fraction division is the content that is important but difficult to learn because it includes the process of finding a numerical expression in the real-world context, the process of making a context that matches a numerical expression, how to solve division, and the justification of standard algorithm. This study analyzes the word problems and problem solving methods about fraction division which elementary pre-service teachers represented. Pre-service teachers have more difficulty in making word problem where the dividend is less than the divisor and they also show typical errors in making the word problems. There were differences in the methods presented according to the contexts of division in problem solving. Through this study, it is necessary to rethink the teaching methods for fraction division instruction in the curriculum for pre-service teachers and analyze the formation process of 'knowledge for content and teaching' because of the differences in responses between grades.

• Journal of Internet Computing and Services
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• v.24 no.4
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• pp.1-13
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• 2023

As federated learning brings a large paradigm to modern artificial intelligence research, efforts are being made to incorporate federated learning into research in various fields. However, researchers who apply federated learning face the problem of choosing a federated learning framework and benchmark tool suitable for their situation and purpose. This study aims to present guidelines for selection of federated learning frameworks and benchmark tools considering the circumstances of researchers who apply federated learning in practice. In particular, there are three main contributions in this study. First, it generalizes the situation of the researcher applying federated learning by combining it with the goal of federated learning and proposes guidelines for selecting a federated learning framework suitable for each situation. Second, it shows the suitability of selection by comparing the characteristics and performance of each federated learning framework to the researcher. Finally, the limitations of the existing federated learning framework and a plan for real-world federated learning operation are proposed.

• Korean Journal of Construction Engineering and Management
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• v.18 no.2
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• pp.21-29
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• 2017

Recently, with having a great interest of the general public for the AR (Augmented Reality) technology, there have been lots of study to improve efficiency of a construction equipment with applying the AR technology to a construction equipment. The clear extrinsic calibration is essential to applying AR technology at the construction site without any error which came from superimposition between 'Real world' and 'Virtual world'. However, on the construction site, the clear extrinsic calibration is not possible, because of lack of time and budget for the specific survey, also, the huge error of the outdoor tracking system such as gyro, GPS system and so on. In this study, we do research about seamless superposition with unclear extrinsic calibration and the image process method for making AR navigator operating in the excavator. Based on this study, we figure that we can fully develop the AR navigator for the excavator. Furthermore, thereby operating AR navigator at many construction sites, we expect that the efficiency of the excavator will be improved. In addition, we can develop AR navigator for not only a excavator but all about construction equipment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1128-1134
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• 2014

Web based simulation service is actively utilized to computably analyze various kinds of phenomena in real world according to progress of computing technology and spread of Network. However it is hard to share data and information among users on the services, because most of web based simulation services do not share and open simulation processing information and results. In this paper, we design a simulation provenance data sharing service on EDISON_CFD (EDucation-research Integration Simulation On the Net for Computational Fluid Dynamics) to share the calculated simulation performance information. To store and share the simulation processing information, we define the simulation processing step as "Problem ${\rightarrow}$ Plan, Design ${\rightarrow}$ Mesh ${\rightarrow}$ Simulation performance ${\rightarrow}$ Result ${\rightarrow}$ Report." Users can understand a problem solving method through a computer simulation by searching the simulation performance information with Search/Share API of the store. Besides, this opened simulation information can reduce the waste of calculation resource to process same simulation jobs.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.146-160
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• 2020

In the 4th industrial revolution, research on solving urban problems using ICT technology is emerging. Representatively, research is being conducted mainly focusing on smart cities. 3D geo-spatial. Various case studies on smart cities are being conducted to solve urban problems, and in order to effectively implement smart cities, it is implemented on the basis of a digital twin interconnecting physical and virtual environments. To implement a digital twin, the concept of space is essential, and spatial information that composes the real world is also essential. Therefore, in order to implement the digital twin, this study conducted a study on the construction and modeling of 3D geo-spatial information based on the national spatial information establishment regulations and the international standard CityGML for buildings, water facilities, and transportation facilities in Jeonju. In Jeonju, the research area, the LOD was defined, and the possibility of digital twin based on geo-spatial information was determined through data collection, analysis, and construction for each detail. In this study, it is meaningful that a plan to construct geo-spatial information for the implementation of a digital twin is presented, and the result of the construction is modeled as an urban standard model. The results of study are expected to be used as reference for detailed construction plans and standard establishment by governments and local governments promoting smart city and digital twin construction in the future.