• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.38 no.6
• /
• pp.663-670
• /
• 2020

In the present study, we assessed the accuracy of aerial triangulation using a UAV (Unmanned Aerial Vehicle) capable of network RTK (Real-Time Kinematic) survey in a disaster situation that may occur in a semi-urban area mixed with buildings. For a reliable survey of check points, they were installed on the roofs of buildings, and static GNSS (Global Navigation Satellite System) survey was conducted for more than four hours. For objective accuracy assessment, coded aerial targets were installed on the check points to be automatically recognized by software. At the instance of image acquisition, the 3D coordinates of the UAV camera were measured using VRS (Virtual Reference Station) method, as a kind of network RTK survey, and the 3-axial angles were achieved using IMU (Inertial Measurement Unit) and gimbal rotation measurement. As a result of estimation and update of the interior and exterior orientation parameters using Agisoft Metashape, the 3D RMSE (Root Mean Square Error) of aerial triangulation ranged from 0.153 m to 0.102 m according to the combination of the image overlap and the angle of the image acquisition. To get higher aerial triangulation accuracy, it was proved to be effective to incorporate oblique images, though it is common to increase the overlap of vertical images. Therefore, to conduct a UAV mapping in an urgent disaster site, it is necessary to acquire oblique images together rather than improving image overlap.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.11
• /
• pp.5458-5464
• /
• 2012

In LTE-Advanced that different networks coexist, it is considered that it is actually difficult to provide service continuity with a procedural and static control method applied to the existing voice service. This research suggests a resource management framework to support the service continuity effectively based on QoS support. In other words, as context information of mobile terminal and base station changes, set-up of related functions such as ISHO, cell selection, source allocation, load control, and QoS mapping is adapted; each function fits into the change, exchanges the process of reorganization, and interacts; these actions go toward to satisfy service continuity. For this aim, the sequence diagram between the function modules for supporting four kind of ISHO is described and then a scenario for ISHO is considered.

• Journal of Korea Multimedia Society
• /
• v.11 no.2
• /
• pp.143-152
• /
• 2008

Nowadays, many investigators are studying various methodologies concerning event expression for semantic retrieval of video data. However, most of the parts are still using annotation based retrieval that is defined into annotation of each data and content based retrieval using low-level features. So, we propose a method of creation of the motion unit and extracting event through the unit for the more semantic retrieval than existing methods. First, we classify motions by event unit. Second, we define semantic unit about classified motion of object. For using these to event extraction, we create rules that are able to match the low-level features, from which we are able to retrieve semantic event as a unit of video shot. For the evaluation of availability, we execute an experiment of extraction of semantic event in video image and get approximately 80% precision rate.

• The KIPS Transactions:PartC
• /
• v.15C no.6
• /
• pp.455-468
• /
• 2008

In this paper, we propose FAS model for establishing trust based on digital certificates in Grid security framework. The existing RBAC(Role Based Access Control) model is extended to provide permissions depending on the users‘ roles. The FAS model is designed for a system independent integrated Grid security by detailing and extending the fundamental architecture of user, role, and permission. FAS decides each user’s role, allocates access right, and publishes attribute certificate. FAS is composed of three modules: RDM, PCM, and CCM. The RDM decides roles of the user during trust negotiation process and improves the existing low level Grid security in which every single user maps a single shared local name. Both PCM and CCM confirm the capability of the user based on various policies that can restrict priority of the different user groups and roles. We have analyzed the FAS strategy with the complexity of the policy graph-based strategy. In particular, we focused on the algorithm for constructing the policy graph. As a result, the total running time was significantly reduced.

• Journal of KIISE:Databases
• /
• v.33 no.3
• /
• pp.342-352
• /
• 2006

Current studies on storing XML data are focused on either mapping XML data to existing RDBMS efficiently or developing a native XML storage. Some native XML storages store each XML node with parsed object form. Clustering, the physical arrangement of each object, can be an important factor to increase the performance with this storing method. In this paper, we propose re-clustering techniques that can store an XML document efficiently. Proposed clustering technique uses path similarities among data nodes, which can reduce page I/Os when returning query results. And proposed technique can process a path query only using small number of clusters as possible instead of using all clusters. This enables efficient processing of path query because we can reduce search space by skipping unnecessary data. Finally, we apply existing clustering techniques to store XML data and compare the performance with proposed technique. Our results show that the performance of XML storage can be improved by using a proper clustering technique.

• Archives of design research
• /
• v.20 no.1 s.69
• /
• pp.177-188
• /
• 2007

This study is about the design of teaching assistant robots that helps elementary school teachers while giving lectures. It focuses on finding images which fits the role of teaching assistant robots, not merely suggesting several designs of robots that are just preferred by children. For this study, the qualities that satisfy the role of teaching assistant were studied by literature reviewing. These qualities were grouped and prioritized to arrange them as role images of teaching assistant robot, through questionnaire to teachers and student teachers. Using the role images and basic adjectives as standards, children performed the image mapping with the pictures of existing robots. This allowed us to find out how children accept the external features of each robot, and which external feature has to be used in order to reveal the role images. And taking form of workshop, children expressed their own images of a teaching assistant robot, a robot's height and location in classroom was surveyed. Based on these studies', three design guidelines of teaching assistant robot have been suggested.

• Journal of Korea Multimedia Society
• /
• v.16 no.11
• /
• pp.1288-1296
• /
• 2013

The prominent line at the singe image is the important fact for understanding spatial structure or estimating aesthetic scoring. According to this thesis, the abstraction of the background line helps analyzing vanishing point, reconstitution of 3 dimensions, and determining of image sloppiness. It also makes easy to calculate the rule of thirds. This thesis is composed of section hough transform mapping, prioritizing of the prominent line, and selection of the prominent line. These technologies are departmentalized to be applied abstraction of traffic lane, analyzing of building structure, abstraction of vanishing point, and abstraction of straight line documentation. This gives the choice that users are able to compose technology by considering characteristic of objects and luminous environment. This thesis also can be applied to abstract circle. The interval hough transform is able to select the number of prominent line which users want to abstract. It can analyze important prominent line numbers at the image and then abstract the lines, too. Results of prominent lines by experiments would be show at this thesis.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.4
• /
• pp.492-496
• /
• 2010

Wikipedia as an open encyclopedia contains immense human knowledge written by thousands of volunteer editors and its reliability is also high. In this paper, we propose to automatically construct a Korean named entity dictionary using the several features of the Wikipedia. Firstly, we generate class hierarchies using the class information from each article of Wikipedia. Secondly, the titles of each article are mapped to our class hierarchies, and then we calculate the entropy value of the root node in each class hierarchy. Finally, we construct named entity dictionary with high performance by removing the class hierarchies which have a higher entropy value than threshold. Our experiment results achieved overall F1-measure of 81.12% (precision : 83.94%, recall : 78.48%).

• KIPS Transactions on Software and Data Engineering
• /
• v.4 no.4
• /
• pp.201-208
• /
• 2015

This paper proposes a method for detecting the direction indicator shown in the road surface efficiently from the black box system installed on the vehicle. In the proposed method, the direction indicators are detected by inverse perspective mapping(IPM) and bag of visual features(BOF)-based NN classifier. In order to apply the proposed method to real-time environments, the candidated regions of direction indicator in an image only performs IPM, and BOF-based NN is used for the classification of feature information from direction indicators. The results of applying the proposed method to the road surface direction indicators detection and recognition, the detection accuracy was presented at least about 89%, and the method presents a relatively high detection rate in the various road conditions. Thus it can be seen that the proposed method is applied to safe driving support systems available.

• Journal of Convergence for Information Technology
• /
• v.10 no.10
• /
• pp.123-127
• /
• 2020

In order to obtain the overall fire line information of medium and large forest fires at night, the ground control system was developed to determine whether forest fires occurred through real-time video clips and to calculate the location of the forest fires determined using the location of drones, angle information of video cameras, and altitude information on the map to reduce the time required for regular video matches obtained after the completion of the mission. To verify the reliability of the developed function, the error distance of the aiming position information of the flight altitude star and the image camera was measured, and the location information within the reliable range was displayed on the map. As the function developed in this paper allows real-time identification of multiple locations of forest fires, it is expected that overall fire line information for the establishment of forest fire extinguishing measures will be obtained more quickly.