The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We present novel exploration algorithms and a control law that enable the construction of Voronoi diagrams over unknown areas using a single autonomous vehicle equipped with range sensors. Our control law and exploration algorithms are provably complete. The control law uses range measurements to enable tracking Voronoi edges between two obstacles. Exploration algorithms make decisions at vertices...
Deployment of sensors and routing inside an irregular region is one of the most fundamental challenges of Wireless Sensor Networks. The performance of an effective and efficient sensor network is highly related to the proper configuration and design of the network and effective communication between the sensors deployed. In real scenario, the area that needs to cover, may suffer from natural geographical...
We pinpoint a new sensor self-deployment problem, constructing focused coverage around a point of interest (POI), and introduce an evaluation metric, coverage radius. We propose two solutions, greedy advance (GA) and greedy-rotation-greedy (GRG), which are to our knowledge the first sensor self-deployment algorithms that operate in a purely localized manner and yet provide coverage guarantee. The...
Sleep scheduling protocols are widely used in wireless sensor networks for saving energy in sensor nodes. However, without considering the special requirements of object tracking, conventional sleep scheduling protocols may lead to intolerable degradation of tracking qualities when they are used in object tracking applications. To handle this problem, sleep scheduling protocols tailed for object tracking...
This paper shows how to use an ideal rubber string, which is clamped down at both ends, as a memory device. The information is stored on the string by giving it an initial shape, where the Fourier coefficients of this shape represent the code bits. Once the string is let go, the wave equation governs the oscillatory movements of the string, but it retains the information in the Fourier coefficients...
Aiming at the positioning problem of Ad-Hoc networks of sensors node location, a beacon selected localization algorithm (BSLA) is proposed in this paper. The proposed method considers sufficiently both the topology relationship among beacons and the topology relationship between beacon nodes and unknown nodes. We introduce the concept of collinearity and apply it into the localization of the multihop...
Accurate modelling of primary system activity is key to reliable performance evaluation of dynamic spectrum access (DSA) technologies. Measurements on spectrum use show that in some cases the lengths of the vacant periods in a given frequency band can be correlated, a feature commonly used semi-Markov ON/OFF-models cannot reproduce. In this paper we study the stochastic properties of a simple primary...
Wireless sensor networks have been widely used in environment and habitat monitoring, as well as in military applications such as battlefield surveillance. In this paper, we focus on detecting intruders in such surveillance systems. Our goal is to optimize the network coverage when the network is deployed to detect an intrusion object with the shape of a disc or a rectangle. We study how the size...
IAUV (Intervention Class AUV) is a challenging field for AUV's new development, suitable for underwater manipulation with certain target in limited environment. Visual sensor makes vivid description of the scene, so could be helpful in solving key issues in IAUV autonomous manipulation. Existing visual sensing approaches for IAUV are mostly applicable for target with prior knowledge and may be lack...
We have developed algorithms for a virtual presence and extended defense (VPED) system that automatically learns the detection map of a deployed sensor field without a-priori knowledge of the local terrain. The VPED system is a network of sensor pods, with each pod containing acoustic and seismic sensors. Each pod has a limited detection range, but a network of pods can form a virtual perimeter. The...
We address the problem of tracking points in dense vector fields. Such vector fields may come from computational fluid dynamics simulations, environmental monitoring sensors, or dense point tracking of video data. To track points in vector fields, we capture the distribution of higher-order properties (e.g., properties derived from the gradient of the velocity vector field) in a novel local descriptor...
Monitoring underwater environments is critical for future near-shore exploration and port security. The effectiveness of underwater acoustic sensor systems is affected by the water environment, as sharp gradients in salinity and temperature cause sound to refract and reflect. Sound transmission can be impaired in estuaries where the salinity of the water is highly variable in space, and tidal action...
An estimation method for the shape and size of a target object by using networked binary sensors whose locations are unknown is proposed. Each of those sensors, which individually are incapable of monitoring the target object's shape and size, sends only binary data describing whether or not it detects at every moment the target object. By using these data and the explicit formulas derived in this...
A solution to the coverage problem in wireless sensor networks provides the total number of sensors that are required to cover a given area of deployment. While prior studies have proposed different formulations and solutions to this problem, these studies have not addressed the problem of minimum cost coverage in which full coverage is achieved by using the minimumnumber of sensor nodes for an arbitrary...
In this paper, we propose a distributed scheme to recognize the shape of a dynamic event region in wireless sensor networks; i.e., a scheme to track the shape of a part of a given field concerned with a dynamic event such as gas leakage and a fire. The basic idea of our proposed scheme is to identify several critical points in a given event region, and to periodically check the criticalness of such...
Until now, a number of cutting tools and cutting methods have been developed for improving the machining processes, however they have some difficulties resulting from tool wear and failure. This study considers on-line monitoring of tool wear and failure in metal cutting processes. The proposed on-line monitoring system consists of two parts: the one is the on-line data acquisition system with sensors...
This paper discusses networked sensors that are randomly distributed to monitor and detect a target object moving on a trajectory. On the basis of analysis results, we propose a method for estimating the shape and size of a target object by using sensors whose locations are unknown. It is surprising that sensors that individually are incapable of monitoring the target object's shape can be used to...
Gesture recognition has great potential for mobile and wearable computing. Most papers in this area focus on classifying different gestures, but do not evaluate the distinctiveness of gestures in continuous recordings of gestures in daily life. This paper presents a new approach for the important and challenging problem of gesture recognition in continuous data streams. We use turning points of arm...
This paper presents a mapping process that can be used for autonomous applications like obstacle avoidance and trajectory planning. The process is real-time capable, and works in full 3-D environments. The mapping starts with building an occupancy grid out of sensor data. Within this grid, single objects are recognized and their polygonal shapes are calculated. The model for object shape representation...
In this paper we propose "SoTong" system for enhancing family relationship with relation oriented communication. In the relation oriented communications, we focus on the relationship by representation and promotion of relations together with awareness of other's situation for the connectedness and the coexistence. The system captures and analyzes communication channels among modern families...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.