Papers by Igor Mishkovski
Today, many organizations and institutions have vast collections of datasets and databases filled... more Today, many organizations and institutions have vast collections of datasets and databases filled with information that, in general, can turn out to be very useful for individuals and for the society [1]. The Police is one such institution which is obliged by law to keep an archive of all the information it deals with on a daily basis. All that information about the criminal events that have occurred in the past can be used in many ways. In this work, we present a research project focused on crime analysis using the concept of crime map, which can be very useful for the law enforcement agencies as well as for the citizens. This research project resulted in an effective crime map of the Republic of Macedonia, which consists of about 1800 events in total. With this project we hope to encourage and motivate the Ministry of Internal Affairs, as well as other institutions, to continue liberating valuable data and bring the benefits of the Open Data idea to its citizens.
The recent emergence of the new representation of interconnected layers of networks, called multi... more The recent emergence of the new representation of interconnected layers of networks, called multiplex networks, refocused the research in complex networks. The analysis of these networks requires redefinition of the dynamical processes and topological properties present in one-layered graphs. The main focus in this work is the relation between consensus and synchronization defined on multiplex graphs and edge correlation of the graph layers. We show numerically that the information of edge correlation between layers offers substantial insights in the complex multiplex structure, thus, contributing to simplified and faster analysis and design of multiplex graphs with desired consensus or synchronization properties.
Communications and Network, 2013
ABSTRACT In this work, we conduct a research on the effects of the details of the terrain on the ... more ABSTRACT In this work, we conduct a research on the effects of the details of the terrain on the path establishment in wireless networks. We discuss how the terrain induced variations, that are unavoidably caused by the obstructions and irregularities in the surroundings of the transmitting and the receiving antennas, have two distinct effects on the network. Firstly, they reduce the amount of links in the network connectivity graph causing it to behave more randomly, while decreasing the coverage and capacity of the network. Secondly, they increase the length of the established paths between the nodes. The presented results show how the terrain oblique influences the layout of the network connectivity graph, in terms of different network metrics, and gives insight to the appropriate level of details needed to describe the terrain in order to obtain results that will be satisfyingly accurate.
PloS one, 2015
The advent of publishing anonymized call detail records opens the door for temporal and spatial h... more The advent of publishing anonymized call detail records opens the door for temporal and spatial human dynamics studies. Such studies, besides being useful for creating universal models for mobility patterns, could be also used for creating new socio-economic proxy indicators that will not rely only on the local or state institutions. In this paper, from the frequency of calls at different times of the day, in different small regional units (sub-prefectures) in Côte d'Ivoire, we infer users' home and work sub-prefectures. This division of users enables us to analyze different mobility and calling patterns for the different regions. We then compare how those patterns correlate to the data from other sources, such as: news for particular events in the given period, census data, economic activity, poverty index, power plants and energy grid data. Our results show high correlation in many of the cases revealing the diversity of socio-economic insights that can be inferred using o...
In this paper we assess the vulnerability of different synthetic complex networks by measuring th... more In this paper we assess the vulnerability of different synthetic complex networks by measuring the traffic performance in presence of intentional nodes and edge attacks. We choose which nodes or edges would be attacked by using several centrality measures, such as: degree, eigenvector and betweenness centrality. In order to obtain some information about the vulnerability of the four different complex networks (random, small world, scale-free and random geometric) we analyze the throughput of these networks when the nodes or the edges are attacked using some of the above mentioned strategies. When attack happens, the bandwidth is reallocated among the flows, which affects the traffic utility. One of the obtained results shows that the scale-free network gives the best flow performance and then comes random networks, small world, and the poorest performance is given by the random geometric networks. This changes dramatically after removing some of the nodes (or edges), giving the biggest performance drop to random and scale-free networks and smallest to random geometric and small world networks.
Advances in Intelligent and Soft Computing, 2012
Advances in Intelligent and Soft Computing, 2012
One of the biggest problems in heterogeneous computing is how tasks should be mapped in these kin... more One of the biggest problems in heterogeneous computing is how tasks should be mapped in these kinds of environments. Because this problem of mapping tasks has been shown to be NP-complete, it requires heuristic techniques. Therefore, we present new schedulers based on the apportionment methods used in elections. In order to obtain the performances of these schedulers we compare them with other known and used heuristics in many different parameters. The presented heuristics can be used when the tasks are big and when they can be divided in smaller sub-tasks. The idea behind the new schedulers is to use apportionment methods (used for elections), such as: the Hamilton's method, Jefferson's Method, Webster's method, Huntington-Hill method, Balance method and pure proportional method. Intuitively the Hamilton's method favors the bigger tasks (i.e. gives them more CPU power). The comparison in this paper shows that these apportionment methods can cope well with the other methods when the number of tasks in the system is no bigger than a certain level. The new apportionment scheduler, based on Hamilton's method, copes well with the existing ones and it outperforms the other schedulers when some conditions are met.
The growth in multicore CPUs and the emergence of powerful manycore GPUs has led to proliferation... more The growth in multicore CPUs and the emergence of powerful manycore GPUs has led to proliferation of parallel applications. Many applications are not straight forward to be parallelized. This paper examines the performance of a parallelized implementation for calculating measurements of Complex Networks. We present an algorithm for calculating complex networks topological feature clustering coefficient, and conducted an execution of the serial, parallel and parallel GPU implementations. A hash-table based structure was used for encoding the complex network’s data, which is different than the standard representation, and also speedups the parallel GPU implementations. Our results demonstrate that the parallelization of the sequential implementations on a multicore CPU, using OpenMP produces a significant speedup. Using OpenCL on a GPU produces even larger speedup depending of the volume of data being processed.
2013 21st Telecommunications Forum Telfor (TELFOR), 2013
Network simulators are important tools when used by researchers. However, complex simulations for... more Network simulators are important tools when used by researchers. However, complex simulations for largescale networks (especially if the scenarios are realistic, i.e. introducing terrain details) results in unreasonably long response from the simulator. High performance parallel resources like GPU devices are solution for obtaining results in reasonable time. Additionally, the latest GPU generations have architecture that enables the developer to configure different input parameters, in order to achieve better performance. In this paper we evaluate the performance impact of these configurations for various resolutions of terrains. The obtained results show that there is an impact on the performance, however it is not significant.
Communications in Computer and Information Science, 2011
In this paper, we propose network measures and analytical procedures for modeling the structure a... more In this paper, we propose network measures and analytical procedures for modeling the structure and the behavior of the basic types of organizations, such as: line, functional, line-and-staff, project and matrix organization. In order to obtain some tangible information about the connectivity between employees and structural properties of organizations, we develop network generators for all five types of organizations. We review various roles and groups of employees within the organizational network, and we assess social position and impact of a particular employee. Except, assessed locations of actors within an organizational network, we analyze the structure of network to find specific employees who have similar roles in the organization and have a tendency to be equivalent in terms of their potential to act in the organization. We estimate what is the confidentiality of the organizational network depending on the removal of a certain communication between employees and what is the percentage of communications that disconnect the organization in unconnected parts. Fig. 5. Strength of hierarchy for growing line, functional, line-and-staff, project and matrix organizations.
Matrix multiplication algorithms are very common and widely used for computation in almost any fi... more Matrix multiplication algorithms are very common and widely used for computation in almost any field. There are many implementations for matrix multiplication on different platforms and programming models. GPU devices in the recent years have become powerful computational units that have entered the segment of high performance computing. In this paper we are analysing two approaches for the matrix multiplication algorithm with and without border conditions for parallel GPU execution.
ABSTRACT The proliferation of smartphones and the demand for all-day connectivity has brought exp... more ABSTRACT The proliferation of smartphones and the demand for all-day connectivity has brought exponential growth of global mobile data traffic. To survive the explosive progression and best serve their customers, mobile network operators need to have a better understanding of the nature of traffic carried by cellular networks. Understanding the characteristics of this traffic is important for network design, traffic modelling, resource planning, and network control. In this work we investigate the basic characteristics of smartphone traffic, identifying and understanding the impact of context (location, time, physical interface) on smartphone usage for calls, messages and data traffic. In order to identify and characterize patterns in the user traffic generated by smartphone devices in the mobile networks, we employ naturalistic logging methodology based on non-obtrusive background data collection while aiming for a highly diverse study participants backdrop. Our statistical results present a comprehensive analysis on user habits while using their smartphones on a daily or weekly basis. By taking advantage of the gathered user logs and the statistical analysis of the traffic characteristics, we attempt to design a mobile traffic generator that will create synthetic voice, message and data traffic according to the observed real life traffic characteristics. The generated mobile traffic scenarios can be used not only for modelling the mobile operators’ network (such as 3G and 4G), but also WiFi, mobile ad hoc and sensor networks.
In this paper we present the utilization of cloud computing environment for fast network simulati... more In this paper we present the utilization of cloud computing environment for fast network simulation of wireless ad hoc networks in 3D terrains. Considering 3D terrains involves larger amounts of data, thus the network simulation requires more compute intensive calculations. In this paper we evaluate the usage of cloud computing environment for network terrain aware simulation in order to optimally utilize the available hardware resources. Our experimental results show that there in not a significant decrease of performance when migration to a private cloud environment.
2013 21st Telecommunications Forum Telfor (TELFOR), 2013
ABSTRACT We study the process of synchronization that takes place on multiplex networks, i.e., on... more ABSTRACT We study the process of synchronization that takes place on multiplex networks, i.e., on a set of networks linked through interconnected layers. As a measure for synchronization we use the eigenratio between the largest and the smallest eigenvalue of the Laplacian matrix of the multiplex graph. Using this measure we analyze how the synchronization depends on the weight of the interconnection links in a given multiplex network. Furthermore, the main results of this work show that even though a network has a bigger eigenratio than other networks, when it is multiplexed with other networks its synchronization rate can be slowed. The results from this work can be easily applied in modeling and analyzing the process of opinion formation in social networks and synchronization in Smart Grid.
Advances in Computer …, Jan 1, 2008
The development of ubiquitous computing and mobility opens challenges for implementation of grid ... more The development of ubiquitous computing and mobility opens challenges for implementation of grid computing in ad hoc network environments. In this paper, a new grid computing implementation for ad hoc networks is proposed. The proposed addition of the ad hoc network protocols suite offers an easy and effective way to exploit the computing power of the network nodes. The model is implemented in the NS-2 network simulator providing the possibility to investigate its performances and tune the network grid parameters.
Understanding Complex Systems, 2012
ABSTRACT In this chapter, the subject of synchronization is introduced and discussed considering ... more ABSTRACT In this chapter, the subject of synchronization is introduced and discussed considering the effects due to network topology. The chapter is organized as follows: (a) after a brief recap of a method due to Pecora and Carroll for checking the conditions for identical synchronization, several of the most popular topologies are considered, showing their influence on network synchronizability; (b) a technique, useful to find out the onset of synchronization in network of periodic oscillators is described in detail; (c) some simulation examples are given; (d) the case of synchronization in networks of nearly identical oscillators is illustrated by examples.
Proceedings of 2010 IEEE International Symposium on Circuits and Systems, 2010
In this paper we present a simple, fast, novel algorithm for building networks whose topology has... more In this paper we present a simple, fast, novel algorithm for building networks whose topology has high synchronizability, is robust against failures, and supports efficient communication. We show that the algorithm is able to build these networks in a small number of steps that scales with the networks density. In addition, we track the evolution of different topological properties in the process of generating these networks. The results show that the topological properties are homogeneously distributed and the topology is less authoritative. Furthermore, we show that the networks we generate are more robust than random, geometric random, small-world or scalefree networks with similar average connectivity. Finally, all of the results indicate that the topology of these networks is entangled, which in many cases represents an optimal topology. 978-1-4244-5309-2/10/$26.00 ©2010 IEEE
Studies in Computational Intelligence, 2011
In this chapter we give an overview and the state of the art in the field of Chaos-based cryptogr... more In this chapter we give an overview and the state of the art in the field of Chaos-based cryptography. The public key cryptosystems based on Chebyshev polynomials enjoy some nice chaotic properties, which makes them suitable for use in both encryption and digital signature. The cryptosystem can work either on real or integer numbers. The cryptosystem that works on real
2012 20th Telecommunications Forum (TELFOR), 2012
ABSTRACT Small-to-medium businesses have embraced cloud technologies achieving cost reduction and... more ABSTRACT Small-to-medium businesses have embraced cloud technologies achieving cost reduction and less administration. In this paper we present the decision making process that involves thorough planning before deciding on the cloud based business collaboration suite that will meet the expected needs. Additionally, in order to help the last stage of planning and deciding a comparison of the most popular options is given as well as a discussion about the pros and cons of the reviewed options.
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Papers by Igor Mishkovski