• Journal of Intelligence and Information Systems
• /
• v.11 no.1
• /
• pp.153-167
• /
• 2005

In this paper, we consider the problem of exploring unknown environments with a mobile robot or an autonomous character agent. Traditionally, research efforts to address the space exploration problem havefocused on the graph-based space representations and the graph search algorithms. Recently EXPLORE, one of the most efficient search algorithms, has been discovered. It traverses at most min$min(mn, d^2+m)$ edges where d is the deficiency of a edges and n is the number of edges and n is the number of vertices. In this paper, we propose DFS-RTA* and DFS-PHA*, two real-time graph search algorithms for directing an autonomous agent to explore in an unknown space. These algorithms are all built upon the simple depth-first search (DFS) like EXPLORE. However, they adopt different real-time shortest path-finding methods for fast backtracking to the latest node, RTA* and PHA*, respectively. Through some experiments using Unreal Tournament, a 3D online game environment, and KGBot, an intelligent character agent, we analyze completeness and efficiency of two algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.5
• /
• pp.1199-1206
• /
• 2015

This paper introduces an algorithm for computing similarity between two poses in the motion capture data with different scale of skeleton, different number of joints and different joint names. The proposed algorithm first performs the topological analysis on the skeleton hierarchy for classifying the joints into more meaningful groups. The global joints positions of each joint group then are aggregated into a point cloud. The number of joints and their positions are automatically adjusted in this process. Once we have two point clouds, the algorithm finds an optimal 2D transform matrix that transforms one point cloud to the other as closely as possible. Then, the similarity can be obtained by summing up all distance values between two points clouds after applying the 2D transform matrix. After some experiment, we found that the proposed algorithm is able to compute the similarity between two poses regardless of their scale, joint name and the number of joints.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.12
• /
• pp.2297-2304
• /
• 2016

In this study, we designed and developed the virtual reality Exergame using the smart mat and the camera sensor for exercises in indoor environments. For detecting the gestures of a upper body of users, the KINECT camera based the gesture recognition algorithm used angles between user's joint information system was adopted, and the smart mat system including a LED equipment and Bluetooth communication module was developed for user's stepping data during the exercises that requires the gestures and stepping of users. Finally, the integrated virtual reality Exergame system was implement along with the Unity 3D engine and different kinds of user' virtual avatar characters with entertainment game contents such as displaying gesture guideline and a scoring function. Therefore, the designed system will useful for elders who need to improve cognitive ability and sense of balance or general users want to improve exercise ability and the indoor circumstances such home or wellness centers.

• Journal of Information Technology Applications and Management
• /
• v.18 no.2
• /
• pp.1-21
• /
• 2011

In this era of convergence, which is characterized by the integration and combination of technology and industries, broadcasting and communications, offline and online, and devices and services, the content industry is also experiencing rapid changes including inter-genre exchange, the creation of new industries, and customized demand. Specifically, IT-based digital content industries such as the online game, e-book, mobile contents and web portal industries are no longer restricted to the boundaries of video, music and games but are being expanded into the realms of education, medicine, fashion and sports thanks to CT innovation of 3D, CG, AR/VR, VFX, etc. As such, various countries have come to recognize the convergent content industry as a new growth engine that will pick up where the IT industry left off, and are forming policies for its development accordingly. This research aims to optimize the system of content taxonomy which is currently genre-focused and unable to support technological development and convergence, and to discover and select star contents to be rigorously developed with governmental support. In this paper, 20 star contents in 8 areas were selected, and these are expected to create tremendous cultural and economic value through ongoing technological and industrial development.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.2
• /
• pp.153-163
• /
• 2011

Smartphone is a mobile device which can perform better than feature phone. Recently, growth in demand for advanced mobile devices boasting powerful performance, market share of smartphone is increasing rapidly in mobile device market, for example, iphone and android phone. Smartphone can provide many functionalities, e-mail, scheduler, word-processing, 3D-game, and etc, based on its powerful performance. Thus, various secret information is integrated in smartphone. To provide service, sometimes, smartphone transmits informations to outside via wireless network. Because smartphone is a mobile device, user can lose his/her smartphone, easily, and losing smartphone can cause serious security threats, because of integrated information in smartphone. Also data which is transmitted in wireless network can be protected for privacy. Thus, in present, it is very important to keep secure smartphone. In this paper, we analyze threats and vulnerabilities of smartphone based on its environments and describe countermeasures against threats and vulnerabilities.