• Title/Summary/Keyword: Trajectory-based

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A Study on Effect Analysis of Trajectory-Based Arrival Management using Continuous Descent Operations (연속강하운용을 이용한 궤적 기반의 항공기 도착 관리 효과 분석 연구)

  • Eun-Mi Oh;Daekeun Jeon
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.30 no.4
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    • pp.1-8
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    • 2022
  • In this study, we propose trajectory-based arrival management using CDO (Continuos Descent Operations). The operational procedures with TBO (Trajectory-Based Operations) concept were established to allow aircraft and ground system to share the trajectories with each other in real time. The proposed operational concept was validated in the air traffic control simulation environment, which consists of controller working position, pseudo pilot system, air traffic generation system, and controllers' decision support system for arrival management using CDO. Simulation results compared with actual flight data indicate that proposed concept could improve the efficiency of traffic flow management in terms of total descending time and fuel consumption. And it was confirmed that if there is a system that can share and utilize the synchronized trajectory, it can be helpful to control arrival aircraft and apply CDO concept.

A Longitudinal Study of Science Core School Students' STEM Career Motivation (과학중점고등학교 학생들의 이공계 진로동기에 대한 종단분석)

  • Shin, Sein;Rachmatullah, Arif;Ha, Minsu;Lee, Jun-Ki
    • Journal of The Korean Association For Science Education
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    • v.36 no.6
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    • pp.835-849
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    • 2016
  • The purpose of the present study is to analyze the trajectory of science core school students' STEM career motivation and to examine the relationship between the trajectory patterns and students' tracks. Longitudinal STEM career motivation data with seven constructs were collected from 256 students for five semesters and the data were analyzed by using group-based trajectory modelling analysis. In order to examine the relationship between trajectory pattern groups and the tracks, chi-square tests were conducted. Based on our findings, we found that students are likely to have similar trajectory patterns in STEM career education experience and in their perception towards STEM career value. In terms of parents' support, academic self-efficacy and STEM career motivation aspects are divided into two distinctive trajectory groups ('high' and 'low' group), while two other variables, STEM career self-efficacy and STEM career interest, are divided into three trajectory groups ('moderate declining', 'high declining', 'increasing' group). Most of the trajectory groups are shown the pattern that the level of each constructs increase until their second academic year, then after that, the patterns started going down. Moreover, there are significant relationship between track and each trajectory groups. Science track and science-core track students have similar trajectory patterns. In contrast, humanities track students have different trajectory groups in some constructs. Based on these findings, we suggest that STEM career education environment should consider various patterns of students' STEM career development.

A Hybrid Algorithm for Online Location Update using Feature Point Detection for Portable Devices

  • Kim, Jibum;Kim, Inbin;Kwon, Namgu;Park, Heemin;Chae, Jinseok
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.2
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    • pp.600-619
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    • 2015
  • We propose a cost-efficient hybrid algorithm for online location updates that efficiently combines feature point detection with the online trajectory-based sampling algorithm. Our algorithm is designed to minimize the average trajectory error with the minimal number of sample points. The algorithm is composed of 3 steps. First, we choose corner points from the map as sample points because they will most likely cause fewer trajectory errors. By employing the online trajectory sampling algorithm as the second step, our algorithm detects several missing and important sample points to prevent unwanted trajectory errors. The final step improves cost efficiency by eliminating redundant sample points on straight paths. We evaluate the proposed algorithm with real GPS trajectory data for various bus routes and compare our algorithm with the existing one. Simulation results show that our algorithm decreases the average trajectory error 28% compared to the existing one. In terms of cost efficiency, simulation results show that our algorithm is 29% more cost efficient than the existing one with real GPS trajectory data.

ECoMOT : An Efficient Content-based Multimedia Information Retrieval System Using Moving Objects' Trajectories in Video Data (ECoMOT : 비디오 데이터내의 이동체의 제적을 이용한 효율적인 내용 기반 멀티미디어 정보검색 시스템)

  • Shim Choon-Bo;Chang Jae-Woo;Shin Yong-Won;Park Byung-Rae
    • The KIPS Transactions:PartB
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    • v.12B no.1 s.97
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    • pp.47-56
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    • 2005
  • A moving object has a various features that its spatial location, shape, and size are changed as time goes. In addition, the moving object has both temporal feature and spatial feature. It is one of the highly interested feature information in video data. In this paper, we propose an efficient content-based multimedia information retrieval system, so tailed ECoMOT which enables user to retrieve video data by using a trajectory information of moving objects in video data. The ECoMOT includes several novel techniques to achieve content-based retrieval using moving objects' trajectories : (1) Muitiple trajectory modeling technique to model the multiple trajectories composed of several moving objects; (2) Multiple similar trajectory retrieval technique to retrieve more similar trajectories by measuring similarity between a given two trajectories composed of several moving objects; (3) Superimposed signature-based trajectory indexing technique to effectively search corresponding trajectories from a large trajectory databases; (4) convenient trajectory extraction, query generation, and retrieval interface based on graphic user interface

Storing and Querying Trajectory Information on PostgreSQL/PostGIS (PostgreSQL/PostGIS 기반의 궤적 정보 저장 및 질의)

  • Yang, Pyoung-Woo;Lee, Yong-Mi;Lee, Yon-Sik;Nam, Kwang-Woo
    • Spatial Information Research
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    • v.19 no.2
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    • pp.57-64
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    • 2011
  • This paper describes how to storing and querying trajectory information on PostgreSQL/PostGIS. Recently as technology of mobile devices is advancing, many researches for location-based services and moving object's trajectory have been studied. Trajectory is the set of information of the location by the time, and is one of the most im portant information for location-based services. Traditional spatial database systems do not support trajectory data types and functions. In this paper, we propose a trajectory data type and query functions for moving objects on PostgreSQL/PostGIS.

Study on Trajectory Prediction Accuracy Analysis Method for Performance Improvement of a Trajectory Prediction Module of Arrival Manager (도착관리시스템 궤적 예측 모듈의 성능 개선을 위한 궤적 예측 정확도 분석 방법 연구)

  • Oh, Eun-Mi;Kim, Hyounkyoung;Eun, Yeonju;Jeon, Daekeun
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.23 no.3
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    • pp.28-34
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    • 2015
  • An analysis method of trajectory prediction has been suggested and the developed trajectory prediction module, which is an important functional component of the Arrival Manager (AMAN) of Jeju airport, has been tested by applying the suggested method. The objective of this method is to improve prediction performance of the trajectory prediction module. The trajectory prediction module predicts the trajectories based on the real-time track data and flight plans. Therefore, the suggested analysis method includes the simulation framework which is based on real-time playback, recording, and graphic display systems for testing. Besides, the definition of time error, which is a important index for the time based scheduling system, such as AMAN, is included in the suggested analysis method. An example of arrival time prediction accuracy improvement through the suggested analysis method has also been presented.

A Combination Method of Trajectory Data using Correlated Direction of Collected GPS Data (수집한 GPS데이터의 상호방향성을 이용한 경로데이터 조합방법)

  • Koo, Kwang Min;Park, Heemin
    • Journal of Korea Multimedia Society
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    • v.19 no.8
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    • pp.1636-1645
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    • 2016
  • In navigation systems that use collected trajectory for routing, the number and diversity of trajectory data are crucial despite the infeasible limitation which is that all routes should be collected in person. This paper suggests an algorithm combining trajectories only by collected GPS data and generating new routes for solving this problem. Using distance between two trajectories, the algorithm estimates road intersection, in which it also predicts the correlated direction of them with geographical coordinates and makes a decision to combine them by the correlated direction. With combined and generated trajectory data, this combination way allows trajectory-based navigation to guide more and better routes. In our study, this solution has been introduced. However, the ways in which correlated direction is decided and post-process works have been revised to use the sequential pattern of triangles' area GPS information between two trajectories makes in road intersection and intersection among sets comprised of GPS points. This, as a result, reduces unnecessary combinations resulting redundant outputs and enhances the accuracy of estimating correlated direction than before.

Design and Implementation of a Trajectory-based Index Structure for Moving Objects on a Spatial Network (공간 네트워크상의 이동객체를 위한 궤적기반 색인구조의 설계 및 구현)

  • Um, Jung-Ho;Chang, Jae-Woo
    • Journal of KIISE:Databases
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    • v.35 no.2
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    • pp.169-181
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    • 2008
  • Because moving objects usually move on spatial networks, efficient trajectory index structures are required to achieve good retrieval performance on their trajectories. However, there has been little research on trajectory index structures for spatial networks such as FNR-tree and MON-tree. But, because FNR-tree and MON-tree are stored by the unit of the moving object's segment, they can't support the whole moving objects' trajectory. In this paper, we propose an efficient trajectory index structure, named Trajectory of Moving objects on Network Tree(TMN Tree), for moving objects. For this, we divide moving object data into spatial and temporal attribute, and preserve moving objects' trajectory. Then, we design index structure which supports not only range query but trajectory query. In addition, we divide user queries into spatio-temporal area based trajectory query, similar-trajectory query, and k-nearest neighbor query. We propose query processing algorithms to support them. Finally, we show that our trajectory index structure outperforms existing tree structures like FNR-Tree and MON-Tree.

Query Slipping Prevention for Trajectory-based Contents Publishing and Subscribing in Wireless Sensor Networks (무선 센서 네트워크에서의 궤도 기반 콘텐츠 발간 및 구독을 위한 질의 이탈 방지)

  • Tscha, Yeong-Hwan
    • Journal of KIISE:Information Networking
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    • v.32 no.4
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    • pp.525-534
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    • 2005
  • This paper is concerned with the query slipping and its prevention for trajectory-based matchmaking service in wireless sensor networks. The problem happens when a query propagating along a subscribe trajectory moves through a publish trajectory without obtaining desired information, even though two trajectories intersect geometrically. There follows resubmission of the query or initiation of another subscribe trajectory Thus, query slipping results in considerable time delay and in the worst, looping in the trajectory or query flooding the network. We address the problem formally and suggest a solution. First, the area where nodes are distributed is logically partitioned into smaller grids, and a grid-based multicast next-hop selection algorithm is proposed. Our algorithm not only attempts to make the trajectory straight but also considers the nodal density of recipient nodes and the seamless grid-by-grid multicast. We prove that the publishing and subscribing using the algorithm eventually eliminate the possibility of the slipping. It toms out that our algorithm dissipates significantly less power of neighbor nodes, compared to the non grid-based method, as greedy forwarding, and the fixed- sized grid approach, as GAF (Geographical Adaptive Fidelity)

Simulation Model Construction for Real-Time Monitoring of Traffic Signal Controller (교통신호제어기 실시간 감시를 위한 시뮬레이션 모델 구축)

  • Kim, Eun-Young;Chang, Dae-Soon;Jang, Jung-Sun;Park, Sang-Cheol
    • Journal of the Korean Institute of Plant Engineering
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    • v.23 no.4
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    • pp.21-27
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    • 2018
  • This paper proposed the real-time monitoring methodology of a traffic signal controller. The proposed methodology is based on the simulation technology, and it is necessary to construct a simulation model imitating the behavior of a traffic signal controller. By executing the simulation model, we can obtain the 'nominal system trajectory' of the traffic signal controller. On the other hand, an IoT(Internet of Things)-based monitoring device is implemented in a traffic signal controller. Through the monitoring device, it is possible to obtain the 'actual system trajectory'. By comparing the nominal system trajectory and the actual system trajectory, we can estimate the degree of deterioration of a traffic signal controller.