Dejan Rančić

Software prototype for solving multi-objective machining optimization problems: Application in non-conventional machining processes

Abstract For an effective and efficient application of machining processes it is often necessary to consider more than one machining performance characteristics for the selection of optimal machining parameters. This implies the need to formulate and solve multi-objective optimization problems. In recent years, there has been an increasing trend of using meta-heuristic algorithms for solving multi-objective machining optimization problems. Although having the ability to efficiently handle highly non-linear, multi-dimensional and multi-modal optimization problems, meta-heuristic algorithms are plagued by numerous limitations as a consequence of their stochastic nature. To overcome some of these limitations in the machining optimization domain, a software prototype for solving multi-objective machining optimization problems was developed. The core of the developed software prototype is an algorithm based on exhaustive iterative search which guarantees the optimality of a determined solution in a given discrete search space. This approach is justified by a continual increase in computing power and memory size in recent years. To analyze the developed software prototype applicability and performance, four case studies dealing with multi-objective optimization problems of non-conventional machining processes were considered. Case studies are selected to cover different formulations of multi-objective optimization problems: optimization of one objective function while all the other are converted into constraints, optimization of a utility function which combines all objective functions and determination of a set of Pareto optimal solutions. In each case study optimization solutions that had been determined by past researchers using meta-heuristic algorithms were improved by using the developed software prototype.

GIS-augmented video surveillance

Registration in augmented reality is a process that merges virtual objects generated by a computer with real-world images captured by a camera. In this article, we present a method for registration of geospatial data applicable to outdoor video surveillance systems consisting of several PTZ cameras. PTZ is an abbreviation for pan-tilt-zoom, and in the terminology of video surveillance it indicates cameras that can rotate in the horizontal (pan) and vertical planes (tilt) and change their level of magnification (zoom). Registration is based on transforming these relative camera view parameters into the absolute position, orientation and field of view required by the three-dimensional geographic information systems (3D GISs). Once the 3D GIS and camera views are aligned, it is possible to identify geospatial objects from the camera image, as well as to overlap the virtual scene with the real one. In addition, inverse transformation of the view parameters allows for selecting and pointing the appropriate camera to some geo-referenced feature or event. Based on the proposal, we developed GeoScopeAVS, a GIS-based system for augmented video surveillance and suggested application of such a system in emergency situation management and urban planning.

Prediction of bus motion and continuous query processing for traveler information services

The paper presents the methods for prediction of bus arrival times and continuous query processing as foundations of traveler information services. The time series of data from automatic vehicle location (AVL) system, consisting of time, location and speed data, is used with historical statistics and bus schedule information to predict future arrivals and motion. Based on predicted and AVL data, continuous query processing technique is proposed to extend traveler information service with notification/alarm features. Extensive experiments have shown that the proposed algorithm for bus motion prediction is efficient enough to function in real conditions and that augmented with continuous query processing techniques can produce services that useful to the travelers.

Integration of GIS and video surveillance

ABSTRACT This paper discusses the integration of three-dimensional (3D) geographic information systems (GIS) and video surveillance systems using augmented reality (AR) techniques. The motivation for this integration is to overcome problems faced by conventional video surveillance systems. Explicit information concerning which camera currently monitors what area in such systems is missing; therefore, insight into the situation depends heavily on the operator’s training and experience. To ensure the complete coordination and monitoring of a situation in a system with multiple cameras, it is necessary to introduce a single reference system. GIS arises as a natural solution because it not only provides a solid ground truth but also provides semantic information that can be highly important in certain video surveillance applications. To integrate information into a GIS application, that information must be georeferenced. Based on our previous research regarding the addition of georeferencing information to surveillance video, this paper introduces models that can be applied to help integrate video and GIS. With an analogy to Milgram’s continuum between the real world and virtual reality, and analogous to the augmented reality and augmented virtuality in Milgram’s continuum, two models of integration are defined here: GIS-augmented video and video-augmented GIS. Then, we define the architecture of GIS-based video surveillance based on these proposed integration models, and finally, a prototype is implemented. The implemented prototype serves as a basis for analysing possible applications of real-world systems based on the integration of GIS and video.

Performance analysis of wireless communication system in general fading environment subjected to shadowing and interference

In this paper, performance analysis of wireless communication over α−η−μ fading channels has been investigated. First, analysis has been carried out for the case when communication is subjected to the influence of co-channel interference. Closed-form expressions have been derived for the probability density function and cumulative distribution function of the received signal-to-interference ratio. Outage probability has been obtained for this case, in the function of various values of system parameters, and also for the case when selection diversity has been presented at the reception. Further, simultaneous multipath fading and shadowing occurrence has been analyzed, through deriving novel composite Gamma long-time faded α−η−μ fading distribution. First-order statistical parameters have been obtained in closed form, for this novel composite distribution, and capitalizing on them, standard performance measures have been efficiently evaluated, graphically presented and discussed in the function of system parameters.

Ellipsoidal Clipmaps - A planet-sized terrain rendering algorithm

Terrain visualization is an important aspect of many applications, especially of 3D geographic information systems, which try to preserve the accuracy of the applied terrain model. A discrepancy of data representation, efficient streaming and the application to a chosen mathematical model of the whole planet, still imposes a challenge to a number of large terrain rendering engines. In this paper, we present ellipsoidal clipmaps - a new way to apply geometry clipmaps to an ellipsoid. The ellipsoid is divided into three partitions, seamlessly stitched together. Unlike previous geometry clipmap approaches, based on preloaded grid upon which the terrain is elevated, the underlying ellipsoidal grid is generated on the fly in the vertex shader. The proposed method guarantees sub-pixel precision of the planet Earth reference ellipsoid surface calculation, exploiting GPU single precision floating-point arithmetic. A tight coupling with the implementation of clipmaps enables consistent caching and fast data streaming, while the usage of equidistant cylindrical projection for the source data minimizes preprocessing and preserves low-to-moderate texture distortion. Graphical abstractDisplay Omitted HighlightsA real-time visualization of the planet Earth.The surface is divided into three partitions seamlessly stitched in the globe.A sub-pixel precise WGS84 reference ellipsoid generation on the fly.Consistent caching and fast data streaming through geometry clipmap application.Minimizing texture distortion through the usage of geographic projection.

A Method for Estimating Surveillance Video Georeferences

The integration of a surveillance camera video with a three-dimensional (3D) geographic information system (GIS) requires the georeferencing of that video. Since a video consists of separate frames, each frame must be georeferenced. To georeference a video frame, we rely on the information about the camera view at the moment that the frame was captured. A camera view in 3D space is completely determined by the camera position, orientation, and field-of-view. Since the accurate measuring of these parameters can be extremely difficult, in this paper we propose a method for their estimation based on matching video frame coordinates of certain point features with their 3D geographic locations. To obtain these coordinates, we rely on high-resolution orthophotos and digital elevation models (DEM) of the area of interest. Once an adequate number of points are matched, Levenberg–Marquardt iterative optimization is applied to find the most suitable video frame georeference, i.e., position and orientation of the camera.

Outage probability of macrodiversity system in the presence of Gamma long term fading Rayleigh short term fading and Nakagami-m CCI

Macro-diversity (MaD) system with MaD selection combining (SC) receiver and two micro-diversity (MiD) SC structures in the shadowed multipath fading channel in the presence of co-channel interference (CCI) is investigated. The received signal propagates through Gamma shadowed Rayleigh fading channel while CCI propagates through Gamma shadowed Nakagami-m multipath fading channel. Novel, infinite series expression for cumulative distribution functions (CDF) is efficiently calculated and used for derivation of outage probability (OP) at the output of MaD system. The effect of the system parameters on the MaD system are presented and analyzed.

Intelligent Agents and Game-Based Learning Modules in a Learning Management System

Many researchers have taken a great deal of effort to promote high quality game-based learning applications, such as educational games, animations, simulations, animated or interactive simulation mechanisms in learning management system (LMS), and so on. The Bloom’s taxonomy strategy was successfully implemented as effective gaming model in two different game-based learning applications (puzzle and platformer games) that motivate and actively engage college students in order to make learning process more enjoyable. During using the game-based modules in LMS Moodle, special attention was paid both to the integration of game-play aspects and the relationship between learning styles and game genres. In this paper we shall describe the proposed approach and introduce an adaptation and personalization of player as student model based on game genres. We have analyzed learning styles and teaching strategies that match the game features which resulted in embedding the analysis personalization and teaching strategies into the game. This article presents the effectiveness of agent-based approach in teaching strategies of Moodle gaming education resources.

Influence of the different input data volume, on the emergency vehicles relocation optimization process based on the AVL data

If we intent to realize the serious optimization task and if the main goal is the location and relocation of the ambulance vehicles based on the data archived in the history of the movement of these vehicles, at the very beginning we have to make several important decisions. One of the dilemmas is how far to go in the past, or how many destinations to which the vehicle traveled in the past we had to take in account and use as starting point of the analysis. In this paper we try to estimate influence of the different number of destinations to the quality of the optimization solution. For this purpose a specifically defined optimization coefficient is defined and introduced. We use the data extracted from the actual use of the emergency ambulance vehicles in real life and the optimization calculations are carried out using software module made during a live project implementation. The results obtained during this analysis of different scale of input data are illustrated and discussed in several aspects. Addition attention is directed to the most important analysis and that is the behavior and the comparison of the different optimization coefficient values.