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EKF-based Simultaneous Localization and Mapping of Mobile Robot using Laser Corner Pattern Matching (레이저 코너 패턴의 매칭을 이용한 이동 로봇의 EKF 기반 SLAM)

  • Kim, Tae-Hyeong;Park, Tae-Hyoung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.12
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    • pp.2094-2102
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    • 2016
  • In this paper, we propose an extended Kalman filter(EKF)-based simultaneous localization and mapping(SLAM) method using laser corner pattern matching for mobile robots. SLAM is one of the most important problems of mobile robot. However, existing method has the disadvantage of increasing the computation time, depending on the number of landmarks. To improve computation time, we produce the corner pattern using classified and detected corner points. After producing the corner patterns, it is estimated that mobile robot's global position by matching them. The estimated position is used as measurement model in the EKF. To evaluated proposed method, we preformed the experiments in the indoor environments. Experimental results of proposed method are shown to maintain an accuracy and decrease the computation time.

A Study on PWM Pattern for Driving Induction Motor using μ-Processor and One Chip (범용 μ-Processor와 One Chip으로 구현되는 유도전동기 구동 PWM Pattern에 관한 연구)

  • Hwang, Y.M.;Hoe, T.W.;Park, J.H.;Shin, D.R.;Cho, Y.G.;Woo, J.I.
    • Proceedings of the KIEE Conference
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    • 1998.11a
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    • pp.179-181
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    • 1998
  • In this paper, one chip PWM pattern generator which eliminates time delay of computations and improves utilization factor of voltage is proposed. Both amplitude of sinusoidal signal and triangular signal are directly controlled. Thus, time delay of computations can be eliminated, and it is possible to track accurately instantaneous current for a sudden change of load with microprocessor 80C196KC. In addition, setting dead-time is also possible for wide range. From experimental work with inverter system for driving induction motor, the validity of proposed one chip PWM pattern generator is verified.

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An Adaption of Pattern Sequence-based Electricity Load Forecasting with Match Filtering

  • Chu, Fazheng;Jung, Sung-Hwan
    • Journal of Korea Multimedia Society
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    • v.20 no.5
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    • pp.800-807
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    • 2017
  • The Pattern Sequence-based Forecasting (PSF) is an approach to forecast the behavior of time series based on similar pattern sequences. The innovation of PSF method is to convert the load time series into a label sequence by clustering technique in order to lighten computational burden. However, it brings about a new problem in determining the number of clusters and it is subject to insufficient similar days occasionally. In this paper we proposed an adaption of the PSF method, which introduces a new clustering index to determine the number of clusters and imposes a threshold to solve the problem caused by insufficient similar days. Our experiments showed that the proposed method reduced the mean absolute percentage error (MAPE) about 15%, compared to the PSF method.

An Exploratory Analysis on the User Response Pattern and Quality Characteristics of Marketing Contents in the SNS of Regional Government (지역마케팅 콘텐츠의 사용자 반응패턴과 품질특성에 관한 탐색적 분석: 지방자치단체가 운영하는 SNS를 중심으로)

  • Jeong, Yeon-Su;Jeong, Dae-Yul
    • The Journal of Information Systems
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    • v.26 no.4
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    • pp.419-442
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    • 2017
  • Purpose The purpose of this study is to explore the pattern of user response and it's duration time through social media content response analysis. We also analyze the characteristics of content quality factors which are associate with the user response pattern. The analysis results will provide some implications to develop strategies and schematic plans for the operator of regional marketing on the SNS. Design/methodology/approach This study used mixed methods to verify the effects and responses of social media contents on the users who have concerns about regional events such as local festival, cultural events, and city tours etc. Big data analysis was conducted with the quantitative data from regional government SNSs. The data was collected through web crawling in order to analyze the social media contents. We especially analyzed the contents duration time and peak level time. This study also analyzed the characteristics of contents quality factors using expert evaluation data on the social media contents. Finally, we verify the relationship between the contents quality factors and user response types by cross correlation analysis. Findings According to the big data analysis, we could find some content life cycle which can be explained through empirical distribution with peak time pattern and left skewed long tail. The user response patterns are dependent on time and contents quality. In addition, this study confirms that the level of quality of social media content is closely relate to user interaction and response pattern. As a result of the contents response pattern analysis, it is necessary to develop high quality contents design strategy and content posting and propagation tactics. The SNS operators need to develop high quality contents using rich-media technology and active response contents that induce opinion leader on the SNS.

Implement pattern lock security enhancement using thread to measure input time (입력시간을 측정하는 쓰레드를 활용한 패턴 잠금 보안 강화 구현)

  • An, Kyuhwang;Kwon, Hyeokdong;Kim, Kyungho;Seo, Hwajeong
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.23 no.4
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    • pp.470-476
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    • 2019
  • The pattern locking technique applied to smart phones is a locking technique that many people use conveniently. However, the safety of pattern locking techniques is very low compared with other techniques. The pattern locking technique is vulnerable to a shoulder surfing attack, which is based on the user's input and can be interpreted by looking at the movement of the shoulder, and the smudge attack is also vulnerable due to fingerprint drag marks remaining on the mobile phone pad. Therefore, in this paper, we want to add a new security method to check the pressed time by using a thread in the pattern locking scheme to secure the vulnerability. It is divided into short, middle, and long click according to the pressing time at each point. When dragging using the technique, security performance enhances 3n tiems. Therefore, even if dragging in the same 'ㄱ' manner, it becomes a completely different pattern depending on the pressing time at each point.

Precision Analysis of the STOMP(FW) Algorithm According to the Spatial Conceptual Hierarchy (공간 개념 계층에 따른 STOMP(FW) 알고리즘의 정확도 분석)

  • Lee, Yon-Sik;Kim, Young-Ja;Park, Sung-Sook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.12
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    • pp.5015-5022
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    • 2010
  • Most of the existing pattern mining techniques are capable of searching patterns according to the continuous change of the spatial information of an object but there is no constraint on the spatial information that must be included in the extracted pattern. Thus, the existing techniques are not applicable to the optimal path search between specific nodes or path prediction considering the nodes that a moving object is required to round during a unit time. In this paper, the precision of the path search according to the spatial hierarchy is analyzed using the Spatial-Temporal Optimal Moving Pattern(with Frequency & Weight) (STOPM(FW)) algorithm which searches for the optimal moving path by considering the most frequent pattern and other weighted factors such as time and cost. The result of analysis shows that the database retrieval time is minimized through the reduction of retrieval range applying with the spatial constraints. Also, the optimal moving pattern is efficiently obtained by considering whether the moving pattern is included in each hierarchical spatial scope of the spatial hierarchy or not.

Conceptual Framework for Pattern-Based Real-Time Trading System using Genetic Algorithm (유전알고리즘 활용한 실시간 패턴 트레이딩 시스템 프레임워크)

  • Lee, Suk-Jun;Jeong, Suk-Jae
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.36 no.4
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    • pp.123-129
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    • 2013
  • The aim of this study is to design an intelligent pattern-based real-time trading system (PRTS) using rough set analysis of technical indicators, dynamic time warping (DTW), and genetic algorithm in stock futures market. Rough set is well known as a data-mining tool for extracting trading rules from huge data sets such as real-time data sets, and a technical indicator is used for the construction of the data sets. To measure similarity of patterns, DTW is used over a given period. Through an empirical study, we identify the ideal performances that were profitable in various market conditions.

Hydraulic Model Experiment on the Circulation in Sagami Bay, Japan (III) -The Time-Varying States of the Flow Pattern and Water Exchange in Barotropic Rotating Model-

  • Choo Hyo-Sang;Sugimoto Takasige
    • Fisheries and Aquatic Sciences
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    • v.1 no.2
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    • pp.260-268
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    • 1998
  • A flow pattern and water exchange in Sagami Bay is examined using a barotropic hydraulic model. In the model experiments, the volume transports of the Kuroshio Through Flow were changed with time. The results of the model experiments show that when the volume transport is increased with time, water mass and vorticity are transferred to the inner part of the bay by wakes from the western part of the bay. In the case of decrease, as the wakes are ceased, the inner cyclonic circulation water is discharged to the outside of the bay by its southward extension through the Oshima eastern channel. It is found that the water exchange by the short-term variation of volume transport in time is about 20% of all the bay water.

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Personalized Battery Lifetime Prediction for Mobile Devices based on Usage Patterns

  • Kang, Joon-Myung;Seo, Sin-Seok;Hong, James Won-Ki
    • Journal of Computing Science and Engineering
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    • v.5 no.4
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    • pp.338-345
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    • 2011
  • Nowadays mobile devices are used for various applications such as making voice/video calls, browsing the Internet, listening to music etc. The average battery consumption of each of these activities and the length of time a user spends on each one determines the battery lifetime of a mobile device. Previous methods have provided predictions of battery lifetime using a static battery consumption rate that does not consider user characteristics. This paper proposes an approach to predict a mobile device's available battery lifetime based on usage patterns. Because every user has a different pattern of voice calls, data communication, and video call usage, we can use such usage patterns for personalized prediction of battery lifetime. Firstly, we define one or more states that affect battery consumption. Then, we record time-series log data related to battery consumption and the use time of each state. We calculate the average battery consumption rate for each state and determine the usage pattern based on the time-series data. Finally, we predict the available battery time based on the average battery consumption rate for each state and the usage pattern. We also present the experimental trials used to validate our approach in the real world.

An Expert System for the Real-Time Computer Control of the Large-Scale System (대규모 시스템의 실시간 컴퓨터 제어를 위한 전문가 시스템)

  • Ko, Yun-Seok
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.6
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    • pp.781-788
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    • 1999
  • In this paper, an expert system is proposed, which can be effectively applied to the large-scale systems with the diversity time constraints, the objectives and the unfixed system structure. The inference scheme of the expert system have the integrated structure composed of the intuitive inference module and logical inference module in order to support effectively the operating constraints of system. The intuitive inference module is designed using the pattern matching or pattern recognition method in order to search a same or similar pattern under the fixed system structure. On the other hand, the logical inference module is designed as the structure with the multiple inference mode based on the heuristic search method in order to determine the optimal or near optimal control strategies satisfing the time constraints for system events under the unfixed system structure, and in order to use as knowledge generator. Here, inference mode consists of the best-first, the local-minimum tree, the breadth-iterative, the limited search width/time method. Finally, the application results for large-scale distribution SCADA system proves that the inference scheme of the expert system is very effective for the large-scale system. The expert system is implemented in C language for the dynamic mamory allocation method, database interface, compatability.

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