• The KIPS Transactions:PartD
• /
• v.12D no.4 s.100
• /
• pp.507-520
• /
• 2005

The R-trees are usually used for an index of trajectories in moving-objects databases. However, they need to access a number of nodes to trace same trajectories because of considering only a spatial proximity. Overlaps and dead spaces should be minimized to enhance the performance of range queries in moving-objects indexes. Trajectories of moving-objects should be preserved to enhance the performance of the trajectory queries. In this paper, we propose the TP3DR-tree(Trajectory Preserved 3DR-tree) using clusters of trajectories for range and trajectory queries. The TP3DR-tree uses two split policies: one is a spatial splitting that splits the same trajectory by clustering and the other is a time splitting that increases space utilization. In addition, we use connecting information in non-leaf nodes to enhance the performance of combined-queries. Our experiments show that the new index outperforms the others in processing queries on various datasets.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.9
• /
• pp.2057-2064
• /
• 2010

With the development of wireless network technology, the location information of a spatiotemporal object which changes their location is used in various application. Each spatiotemporal object has many location information, hence it is inefficient to search all trajectory information of spatiotemporal objects for a range query. In this paper, we propose an efficient method which divides a trajectory and stores its division data on restricted storage space. Using suboptimal split algorithm, an extended split algorithm that minimizes the volume of EMBRs(Extended Minimum Bounding Box) is designed and simulated. Our experimental evaluation confirms the effectiveness and efficiency of our proposed splitting policy

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.10
• /
• pp.2188-2194
• /
• 2011

With the development of wireless network technology, Storing the location information of a spatiotemporal object was very necessary. Each spatiotemporal object has many unnecessariness location information, hence it is inefficient to search all trajectory information of spatiotemporal objects. In this paper, we propose an efficient method which increase searching efficiency. Using EMBR(Extend Minimun Bounding Rectangle), an LinearMarge split algorithm that minimizes the volume of MBRs is designed and simulated. Our experimental evaluation confirms the effectiveness and efficiency of our proposed splitting policy.

• Journal of computational fluids engineering
• /
• v.19 no.2
• /
• pp.86-92
• /
• 2014

In this paper, prediction of separation trajectory for Two-stage-To-Orbit space launch vehicle has been numerically simulated by using an aerodynamic database based on steady state analysis. Aerodynamic database were obtained for matrix of longitudinal and vertical positions. The steady flow simulations around the launch vehicle have been made by using a 3-D RANS flow solver based on unstructured meshes. For this purpose, a vertex-centered finite-volume method was adopted to discretize inviscid and viscous fluxes. Roe's finite difference splitting was utilized to discretize the inviscid fluxes, and the viscous fluxes were computed based on central differencing. To validate this flow solver, calculations were made for the wind-tunnel experiment model of the LGBB TSTO vehicle configuration on steady state conditions. Aerodynamic database was constructed by using flow simulations based on test matrix from the wind-tunnel experiment. ANN(Artificial Neural Network) was applied to construct interpolation function among aerodynamic variables. Separation trajectory for TSTO launch vehicle was predicted from 6-DOF equation of motion based on the interpolated function. The result of present separation trajectory calculation was compared with the trajectory using experimental database. The predicted results for the separation trajectory shows fair agreement with reference[4] solution.

• Journal of the Korea Computer Graphics Society
• /
• v.23 no.5
• /
• pp.57-66
• /
• 2017

In this paper, we suggest a novel physics-based real-time animation technique for vehicles, and introduce an easy and intuitive animation authoring tool which uses our proposed technique. After a user specifies a trajectory of a virtual car as input, our system produces a more accurate simulation faster than a previous research result. This is achieved by a trajectory splitting method based on directional features and a trajectory library. As a result, the user can create not only a car animation including lane changing and passing, but also a crash animation which is a rarely researched topic. Also, we propose a virtual car structure that approximates a real car's structure for real-time simulation, the resulting animation shows high plausibility such as a small vibration which occurs when the virtual car breaks and a deformation of when a car accident happens.

• The KIPS Transactions:PartD
• /
• v.16D no.2
• /
• pp.161-168
• /
• 2009

Recently, use of various position base servicesthat collect position information for moving object and utilize in real life is increasing by the development of wireless network technology. Accordingly, new index structures are required to efficiently retrieve the consecutive positions of moving objects. This paper addresses an improved trajectory split algorithm for the purpose of efficiently supporting spatio-temporal range queries using index structures that use Minimum Bounding Rectangles(MBR) as trajectory approximations. We consider volume of Extended Minimum Bounding Rectangles (EMBR) to be determined by average size of range queries. Also, Use a priority queue to speed up our process. This algorithm gives in general sub-optimal solutions with respect to search space. Our improved trajectory split algorithm is going to derive minimizing volume of EMBRs better than previously proposed split algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.1
• /
• pp.110-116
• /
• 2013

With the recent development of wireless network technologies, there have been increasing usage of variouse position base servies. Position based services basically collect position information of moving object for the utilization of them in real life. Accordingly, new index structures are required to efficiently retrieve the consecutive positions of moving objects. In the paper, we consider volume of Extended Minimum Bounding Rectangles(EMBR) to be determined by average size of range queries. We proposed the methode that split efficiently moving object with long distance between location, and split moving object for decrease searching space an Estimated-Split algorithm that minimizes the volume of MBRs is designed and simulated. Our experimental evaluation confirms the effectiveness and efficiency of our proposed splitting policy.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.5
• /
• pp.2310-2325
• /
• 2016

In this paper, we provide a trajectory-generation algorithm that can identify pedestrians in real time. Typically, the contours for the extraction of pedestrians from the foreground of images are not clear due to factors including brightness and shade; furthermore, pedestrians move in different directions and interact with each other. These issues mean that the identification of pedestrians and the generation of trajectories are somewhat difficult. We propose a new method for trajectory generation regarding multiple pedestrians. The first stage of the method distinguishes between those pedestrian-blob situations that need to be merged and those that require splitting, followed by the use of trained decision trees to separate the pedestrians. The second stage generates the trajectories of each pedestrian by using the point-correspondence method; however, we introduce a new point-correspondence algorithm for which the A* search method has been modified. By using fuzzy membership functions, a heuristic evaluation of the correspondence between the blobs was also conducted. The proposed method was implemented and tested with the PETS 2009 dataset to show an effective multiple-pedestrian-tracking capability in a pedestrian-interaction environment.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.38 no.11
• /
• pp.771-780
• /
• 2001

It is indispensable to use the process and device simulation tool in order to analyze accurately the electrical characteristics of ULSI CMOS devices, in addition to developing and manufacturing those devices. The 3D Monte Carlo (MC) simulation result is not efficient for large-area application because of the lack of simulation particles. In this paper is reported a new efficient simulation strategy for 3D MC ion implantation into large-area application using the 3D MC code of TRICSI(TRansport Ions into Crystal Silicon). The strategy is related to our newly proposed split-trajectory method and ion-splitting method(ion-shadowing approach) for 3D large-area application in order to increase the simulation ions, not to sacrifice the simulation accuracy for defects and implanted ions. In addition to our proposed methods, we have developed the cell based 3D interpolation algorithm to feed the 3D MC simulation result into the device simulator and not to diverge the solution of continuous diffusion equations for diffusion and RTA(rapid thermal annealing) after ion implantation. We found that our proposed simulation strategy is very computationally efficient. The increased number of simulation ions is about more than 10 times and the increase of simulation time is not twice compared to the split-trajectory method only.

• Journal of Korea Spatial Information System Society
• /
• v.7 no.1 s.13
• /
• pp.13-24
• /
• 2005

Objects, which change their positions over time such as cars, are called moving objects. Trajectories of a moving object have large volumes because trajectories are accumulated. Efficient indexing techniques for searching these large volumes of trajectories are needed in the moving object databases. Especially the TB-tree which supports bundling trajectories is suitable for processing combined queries which have 2 steps: first step is selecting trajectories (range search), next is selecting the parts of each trajectory (trajectory search). But the TB-tree has unnecessary disk accesses cause of lack of spatial discrimination in range queries. In this paper, we propose and implement the splitting polity which can reduce dead spaces of non-leaf node in order to process range queries efficiently. The policy has better performance about range queries than the TB-tree as well as the advantages of the TB-tree, such as highly space utilization and efficient trajectory extraction. This paper shows that the newly proposed split policy has better performance in processing the range queries than that of the TB-tree by experimental evaluation.