基于聚类匹配的移动机器人地图实时创建算法

提出了一种基于模式识别聚类思想的数据点集匹配算法.该匹配算法具有传统迭代匹配算法和非迭代匹配算法的优点,匹配速度快,精度高.结合上述匹配算法,给出了一种基于激光测距仪的移动机器人环境地图实时创建方法.该方法使用从环境数据中提取出的特征点来完成两组激光数据点集的匹配,进而完成环境地图的创建.利用本实验室自主研发的救援机器人平台对该算法进行了验证,实验结果表明,该算法能够完成室内环境下移动机器人实时准确有效的环境地图创建.     

Gossip-based cooperative caching for mobile applications in mobile wireless networks

Cooperative caching is an efficient way to improve the performance of data access in mobile wireless networks, by cache nodes selecting different data items in their limited storage in order to reduce total access delay. With more demands on sharing a video or other data, especially for mobile applications in an Internet-based Mobile Ad Hoc Network, considering the relations among data items in cooperative caching becomes more important than before. However, most of the existing works do not consider these inherent relations among data items, such as the logical, temporal, or spatial relations. In this paper, we present a novel solution, Gossip-based Cooperative Caching (GosCC) to address the cache placement problem, and consider the sequential relation among data items. Each mobile node stores the IDs of data items cached locally and the ID of the data item in use into its progress report. Each mobile node also makes use of these progress reports to determine whether a data item should be cached locally. These progress reports are propagated within the network in a gossip-based way. To improve the user experience, GosCC aims to provide users with an uninterrupted data access service. Simulation results show that GosCC achieves better performance than Benefit-based Data Caching and HybridCache, in terms of average interruption intervals and average interruption times, while sacrificing message cost to a certain degree.     

Real-time building of a thinning-based topological map

An accurate and compact map is essential to an autonomous mobile robot system. A topological map, one of the most popular map types, can be used to represent the environment in terms of discrete nodes with edges connecting them. It is usually constructed by Voronoi-like graphs, but in this paper the topological map is incrementally built based on the local grid map by using a thinning algorithm. This algorithm, when combined with the application of the C-obstacle, can easily extract only the meaningful topological information in real-time and is robust to environment change, because this map is extracted from a local grid map generated based on the Bayesian update formula. In this paper, position probability is defined to evaluate the quantitative reliability of the end node extracted by the thinning process. Since the thinning process builds only local topological maps, a global topological map should be constructed by merging local topological maps according to nodes with high position probability. For real and complex environments, experiments showed that the proposed map building method based on the thinning process can accurately build a local topological map in real-time, with which an accurate global topological map can be incrementally constructed.     

Sentient map – a new paradigm for visual computing

 A sentient map enables the user to view a collection of information items as a map so that gestures, or more specifically c-gestures, can be used for the interaction between the user and the information system. Different c-gestures are dynamically transformed into spatial/temporal queries, or σ-queries, for accessing the information items in multimedia databases and data sources. An application in e-learning called the Growing Book is described. The visual computing paradigm offered by the sentient map can be summarized as follows: “I come, I see, I gesture”.     

实时通告服务设计与实现

OMG通告服务为对策之间提供强有力的解耦通信支持,是CORBA提供的重要服务之一,目前很多应用需要之间的通信具有实时性,而现有的通告服务规范已不能满足这种需求,为此,设计并实现了具有实时功能的通告服务,提出了一种实时通告服务的体系结构,讨论了实时通告服务系统的实现技术。     

Object-spatial layout-route based hybrid map and global localization for mobile robots

This paper presents new object-spatial layout-route based hybrid map representation and global localization approaches using a stereo camera. By representing objects as high-level features in a map, a robot can deal more effectively with different contexts such as dynamic environments, human-robot interaction, and semantic information. However, the use of objects alone for map representation has inherent problems. For example, it is difficult to represent empty spaces for robot navigation, and objects are limited to readily recognizable things. One way to overcome these problems is to develop a hybrid map that includes objects and the spatial layout of a local space. The map developed in this research has a hybrid structure that combines a global topological map and a local hybrid map. The topological map represents the spatial relationships between local spaces. The local hybrid map combines the spatial layout of the local space with the objects found in that space. Based on the proposed map, we suggest a novel coarse-to-fine global localization method that uses object recognition, point cloud fitting and probabilistic scan matching. This approach can accurately estimate robot pose with respect to the correct local space. Recommended by Editor Jae-Bok Song. This research was performed for the Intelligent Robotics Development Program, one of the 21st Century Frontier R&D Programs funded by the Ministry of Knowledge Economy of Korea. Soonyong Park received the B.S. and M.S. degrees from the Department of Mechanical Engineering, Kyunghee University, Seoul, Korea, in 2001 and 2003, respectively. He is currently working toward the Ph.D. degree in the Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea. Since 2001, he has been a student researcher in the Center for Cognitive Robotics Research, Korea Institute of Science and Technology (KIST), Seoul, Korea. His research interests include mobile robot navigation and computer vision. Mignon Park received the B.S. and M.S. degrees in Electronics from Yonsei University, Seoul, Korea, in 1973 and 1977, respectively. He received the Ph.D. degree in University of Tokyo, Japan, 1982. He was a researcher with the Institute of Biomedical Engineering, University of Tokyo, Japan, from 1972 to 1982, as well as at the Massachusetts Institute of Technology, Cambridge, and the University of California Berkeley, in 1982. He was a visiting researcher in Robotics Division, Mechanical Engineering Laboratory, Ministry of International Trade and Industry, Tsukuba, Japan, from 1986 to 1987. He has been a Professor in the Department of Electrical and Electronic Engineering in Yonsei University, since 1982. His research interests include fuzzy control and application, robotics, and fuzzy biomedical system. Sung-Kee Park is a principal research scientist for Korea Institute of Science and Technology (KIST). He received the B.S. and M.S. degrees in Mechanical Design and Production Engineering from Seoul National University, Seoul, Korea, in 1987 and 1989, respectively. He received the Ph.D. degree (2000) from Korea Advanced Institue of Science and Technology (KAIST), Korea, in the area of computer vision. Since then, he has been working for the center for cognitive robotics research at KIST. During his period at KIST, he held a visiting position at the Robotics Institute of Carnegie Mellon University in 2005, where he did research on object recognition. His recent work has been on cognitive visual processing, object recognition, visual navigation, and human-robot interaction.     

Lagrangean relaxation with clusters for point-feature cartographic label placement problems

This paper presents two new mathematical formulations for the point-feature cartographic label placement problem (PFCLP) and a new Lagrangean relaxation with clusters (LagClus) to provide bounds to these formulations. The PFCLP can be represented by a conflict graph and the relaxation divides the graph in small subproblems (clusters) that are easily solved. The edges connecting clusters are relaxed in a Lagrangean way and a subgradient algorithm improves the bounds. The LagClus was successfully applied to a set of instances up to 1000 points providing the best results of those reported in the literature.     

Bisection approach for pixel labelling problem

This paper formulates pixel labelling as a series of two-category classification. Unlike existing techniques, which assign a determinate label to each pixel, we assign a label set to each pixel and shrink the label set step by step. Determinate labelling is achieved within log₂n (n is size of label set) steps. In each step, we bisect the label set into two subsets and discard the one with higher cost of assigning it to the pixel. Simultaneous labelling of an image is carried out by minimizing an energy function that can be minimized via graph cut algorithm. Based on the bisection approach, we propose a bitwise algorithm for pixel labelling, which set one bit of each pixel's label in each step. We apply the proposed algorithm to stereo matching and image restoration. Experimental results demonstrate that both good performance and high efficiency are achieved.     

Personalized recommendation of popular blog articles for mobile applications

Weblogs have emerged as a new communication and publication medium on the Internet for diffusing the latest useful information. Providing value-added mobile services, such as blog articles, is increasingly important to attract mobile users to mobile commerce, in order to benefit from the proliferation and convenience of using mobile devices to receive information any time and anywhere. However, there are a tremendous number of blog articles, and mobile users generally have difficulty in browsing weblogs owing to the limitations of mobile devices. Accordingly, providing mobile users with blog articles that suit their particular interests is an important issue. Very little research, however, has focused on this issue.In this work, we propose a novel Customized Content Service on a mobile device (m-CCS) to filter and push blog articles to mobile users. The m-CCS includes a novel forecasting approach to predict the latest popular blog topics based on the trend of time-sensitive popularity of weblogs. Mobile users may, however, have different interests regarding the latest popular blog topics. Thus, the m-CCS further analyzes the mobile users’ browsing logs to determine their interests, which are then combined with the latest popular blog topics to derive their preferred blog topics and articles. A novel hybrid approach is proposed to recommend blog articles by integrating personalized popularity of topic clusters, item-based collaborative filtering (CF) and attention degree (click times) of blog articles. The experiment result demonstrates that the m-CCS system can effectively recommend mobile users’ desired blog articles with respect to both popularity and personal interests.     

基于像素光照计算的硬件加速技术

给出了基于像素光照计算的原理和硬件体系结构;提出了一种基于像素光照计算的设计分析方法及相应的光照计算参数的纹理表示模型;通过凹凸纹理的实时绘制,给出了不同硬件加速模式下的实现结果.     

Optimization of a Time-to-Digital Converter and a coincidence map algorithm for TOF-PET applications

This contribution describes the optimization of a multichannel high resolution Time-to-Digital Converter (TDC) in a Field-Programmable Gate Array (FPGA) initially capable of obtaining time resolutions below 100 ps for multiple channels. Due to its fast propagation capability it has taken advantage of the FPGA internal carry logic for accurate time measurements. Furthermore, the implementation of the TDC has been performed in different clock regions and tested with different frequencies as well, achieving improvements of up to 50% for a pair of channels. Moreover, since the TDC is potentially going to be used in a trigger system for Positron Emission Tomography (PET), the algorithm for coincidence identification has been subjected to tests in order to estimate the impact on occupied resources and the execution time. This time has been optimized, resulting in speed improvements of up to 20% while preserving occupied resources.     

A two-stage mobile robot localization method by overlapping segment-based maps

This paper presents a new method for accurately estimating the pose (position and orientation) of a mobile robot by registering a segment-based local map observed from the current robot pose and a global map. The method works in a two-stage procedure. First, the orientation is determined by aligning the local and global map through a voting process based on a generalized Hough transform. Second, it uses a coarse-to-fine approach for selecting candidate positions and a weighted voting scheme to determine the degree of overlap of the two maps at each of these poses. Unlike other methods previously proposed, this approach allows us to uncouple the problem of estimating the robot orientation and the robot position which may be useful for some applications. In addition it can manage environments described by many (possibly short) segments. This paper presents some experimental results based on our mobile robot RAM-2 that show the accuracy and the robustness of the proposed method even for poor quality maps and large dead-reckoning errors.     

流程工业实时性能管理平台架构的研究

随着软件体系结构的不断发展,传统的流程工业实时数据库系统已经不适应工业不断变化的需求.分析和比较了国内外先进的流程工业实时性能管理系统,借助于面向服务体系结构(SOA)的设计思想,设计了基于SOA的流程工业实时性能管理平台.     

A comparative study of mobile map displays in a geographic orientation task

In an ergonomic experiment, different mobile map displays were compared in a simulated geographical orientation task. Subjects had to cross mazes while the corresponding maps were presented on a hand-held display, two helmet-mounted displays (a retinal scanning and a liquid crystal display) or on paper. The simulated mazes were projected on a backlit screen and the subjects could cross them using a joystick. The displays were compared with regard to subjects' speed when crossing the mazes, experienced task difficulty, visual fatigue and simulator sickness. The results show that speed was lowest with the paper map and experienced task difficulty was highest, whereas no significant differences were found between the electronic displays. Visual fatigue and simulator sickness were low and no significant differences were observed between all displays. The conclusion is drawn that all electronic map displays can be used for short time periods (15 - 30 minutes); however, long term effects have to be analysed in future experimental studies.     

基于Flash的电子地图制作及在WebGIS中的应用

研究了利用Flash先进的矢量化技术和灵活的图像绘制功能开发WebGIS客户端的方法,满足网络GIS系统的交互功能,阐述了该方法的优势,并分析了用Flash技术与ArcIMS空间服务器结合及与Web应用服务器开发平台结合的关键技术,在.NET环境下对生成的ArcXML空间数据信息进行解析,利用Flash面向对象编程方法对空间实体、图层等进行组织和管理,提出一种开发周期短、成本低廉、高质量地绘制交互灵活的地图的有效方法.     

基于实时数据库的虚拟仪器数据管理方法

比较了虚拟仪器中数据管理的不同方法,将实时数据库技术引入虚拟仪器数据管理中,提出了基于实时数据库管理的虚拟仪器系统模型,分析了实时数据库的特点,接口和实时事务调度方法。     

工业以太网实时性解决方案

首先阐述了目前广泛应用的以太网技术及其通讯的不确定性，介绍了工业环境中对局域网技术及设备的特殊要求，尤其是对网络通讯的可靠性和实时性的苛刻要求，最后提出了基于现场总线技术的工业以太网和最新EPA工业以太网在实时性和通讯确定性方面的解决方案。