Institute for Computer Science and Control

Budapest, Hungary

Institute for Computer Science and Control

Budapest, Hungary
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Galai B.,Institute for Computer Science and Control | Benedek C.,Institute for Computer Science and Control | Benedek C.,Pázmány Péter Catholic University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2017

In this paper, we introduce a new technique for change detection in urban environment based on the comparison of 3D point clouds with significantly different density characteristics. Our proposed approach extracts moving objects and environmental changes from sparse and inhomogeneous instant 3D (i3D) measurements, using as reference background model dense and regular point clouds captured by mobile laser scanning (MLS) systems. The introduced workflow consist of consecutive steps of point cloud classification, crossmodal measurement registration, Markov Random Field based change extraction in the range image domain and label back projection to 3D. Experimental evaluation is conducted in four different urban scenes, and the advantage of the proposed change detection step is demonstrated against a reference voxel based approach. © Springer International Publishing AG 2017.

De Maio V.,University of Innsbruck | Prodan R.,University of Innsbruck | Kecskemeti G.,Institute for Computer Science and Control
Future Generation Computer Systems | Year: 2016

Reducing energy consumption has become a key issue for data centres, not only because of economical benefits but also for environmental and marketing reasons. Therefore, assessing their energy consumption requires precise models. In the past years, many models targeting different hardware components, such as CPU, storage and network interface cards (NIC) have been proposed. However, most of them neglect energy consumption related to VM migration. Since VM migration is a network-intensive process, to accurately model its energy consumption we also need energy models for network transfers, comprising their complete software stacks with different energy characteristics. In this work, we present a comparative analysis of the energy consumption of the software stack of two of today's most used NICs in data centres, Ethernet and Infiniband. We carefully design for this purpose a set of benchmark experiments to assess the impact of different traffic patterns and interface settings on energy consumption. Using our benchmark results, we derive an energy consumption model for network transfers. Based on this model, we propose an energy consumption model for VM migration providing accurate predictions for paravirtualised VMs running on homogeneous hosts. We present a comprehensive analysis of our model on different machine sets and compare it with other models for energy consumption of VM migration, showing an improvement of up to 24% in accuracy, according to the NRMSE error metric. © 2015 Elsevier B.V.

Kovacs L.,Institute for Computer Science and Control | Kovacs L.,University of Szeged
Proceedings of the IEEE International Conference on Computer Vision | Year: 2013

In this paper we present a method for local processing of photos and associated sensor information on mobile devices. Our goal is to lay the foundations of a collaborative multi-user framework where ad-hoc device groups can share their data around a geographical location to produce more complex composited views of the area, without the need of a centralized server-client - cloud-based - architecture. We focus on processing as much data locally on the devices as possible, and reducing the amount of data that needs to be shared. The main results are the proposal of a lightweight processing and feature extraction framework, based on the analysis of vision graphs, and presenting preliminary composite view generation based on these results. © 2013 IEEE.

Kertesz A.,University of Szeged | Kertesz A.,Institute for Computer Science and Control
Proceedings - 4th IEEE International Conference on Big Data and Cloud Computing, BDCloud 2014 with the 7th IEEE International Conference on Social Computing and Networking, SocialCom 2014 and the 4th International Conference on Sustainable Computing and Communications, SustainCom 2014 | Year: 2015

Cloud Computing has reached a maturity state and high level of popularity that various Cloud services have become a part of our lives. The Internet of Things provides a way to improve social networking by interdisciplinary efforts that can be effectively supported by Cloud Computing solutions. In this article we propose novel approaches for composing and interoperating Cloud solutions to support IoT functionality. We exemplify how to manage, share and process user data produced by mobile devices in different IaaS clouds. © 2014 IEEE.

Manno-Kovacs A.,Institute for Computer Science and Control
2014 IEEE International Conference on Image Processing, ICIP 2014 | Year: 2014

Active contour methods are widely used for efficient contour detection. This paper proposes a novel contribution for the Harris based Vector Field Convolution (HVFC) method, using the orientation information of feature points in the image by analyzing the gradient information in the small neighborhood. Based on the orientation information, relevant edges are emphasized and an improved edge map is used in the iterative process. The main advantage of the introduced Directional HVFC (DHVFC) method is the ability of exploiting orientation information for increased contour detection accuracy even in case of high curvature boundaries and strong background clutter. The quantitative and qualitative evaluation and comparison with other state-of-the-art methods show that the additional directional information increases the detection performance. © 2014 IEEE.

Galai B.,Institute for Computer Science and Control | Benedek C.,Institute for Computer Science and Control
2015 International Workshop on Computational Intelligence for Multimedia Understanding, IWCIM 2015 | Year: 2015

In this paper, we present a performance analysis of various descriptors suited to human gait analysis in Rotating Multi-Beam (RMB) Lidar measurement sequences. The gait descriptors for training and recognition are observed and extracted in realistic outdoor surveillance scenarios, where multiple pedestrians walk concurrently in the field of interest, their trajectories often intersect, while occlusions or background noise may affects the observation. For the Lidar scenes, we compared the modifications of five approaches proposed originally for optical cameras or Kinect measurements. Our results confirmed that efficient person re-identification can be achieved using a single Lidar sensor, even if it produces sparse point clouds. © 2015 IEEE.

Balas E.,Carnegie Mellon University | Kis T.,Institute for Computer Science and Control
Discrete Optimization | Year: 2015

This note is meant to elucidate the difference between intersection cuts as originally defined, and intersection cuts as defined in the more recent literature. It also states a basic property of intersection cuts under their original definition. © 2015 Elsevier B.V.

Balas E.,Carnegie Mellon University | Kis T.,Institute for Computer Science and Control
Mathematical Programming | Year: 2016

We examine the connections between the classes of cuts in the title. We show that lift-and-project (L&P) cuts from a given disjunction are equivalent to generalized intersection cuts from the family of polyhedra obtained by taking positive combinations of the complements of the inequalities of each term of the disjunction. While L&P cuts from split disjunctions are known to be equivalent to standard intersection cuts (SICs) from the strip obtained by complementing the terms of the split, we show that L&P cuts from more general disjunctions may not be equivalent to any SIC. In particular, we give easily verifiable necessary and sufficient conditions for a L&P cut from a given disjunction D to be equivalent to a SIC from the polyhedral counterpart of D. Irregular L&P cuts, i.e. those that violate these conditions, have interesting properties. For instance, unlike the regular ones, they may cut off part of the corner polyhedron associated with the LP solution from which they are derived. Furthermore, they are not exceptional: their frequency exceeds that of regular cuts. A numerical example illustrates some of the above properties. © 2016 Springer-Verlag Berlin Heidelberg and Mathematical Optimization Society

Benedek C.,Institute for Computer Science and Control
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings | Year: 2014

In this paper we introduce a probabilistic approach for extracting complex hierarchical object structures from digital images. The proposed framework extends conventional Marked Point Process models by (i) admitting object-subobject ensembles in parent-child relationships and (ii) allowing corresponding objects to form coherent object groups. The proposed method is demonstrated in three application areas: optical circuit inspection, built in area analysis in aerial images, and traffic monitoring on airborne Lidar data. © 2014 IEEE.

Kis T.,Institute for Computer Science and Control
Operations Research Letters | Year: 2015

In this paper we study an extension of the single machine scheduling problem with the total weighted completion time objective, where there is a single non-renewable resource consumed by the jobs, having an initial stock and some additional replenishments over time. We prove that this problem is NP-hard in the strong sense, and provide an FPTAS for a special case with two supply dates. © 2015 Elsevier B.V. All rights reserved.

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