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OALib Journal期刊

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Solving the MDBCS Problem Using the Metaheuric–Genetic Algorithm
Milena Bogdanovic
International Journal of Advanced Computer Sciences and Applications , 2011,
Abstract: The problems degree-limited graph of nodes considering the weight of the vertex or weight of the edges, with the aim to find the optimal weighted graph in terms of certain restrictions on the degree of the vertices in the subgraph. This class of combinatorial problems was extensively studied because of the implementation and application in network design, connection of networks and routing algorithms. It is likely that solution of MDBCS problem will find its place and application in these areas. The paper is given an ILP model to solve the problem MDBCS, as well as the genetic algorithm, which calculates a good enough solution for the input graph with a greater number of nodes. An important feature of the heuristic algorithms is that can approximate, but still good enough to solve the problems of exponential complexity. However, it should solve the problem heuristic algorithms may not lead to a satisfactory solution, and that for some of the problems, heuristic algorithms give relatively poor results. This is particularly true of problems for which no exact polynomial algorithm complexity. Also, heuristic algorithms are not the same, because some parts of heuristic algorithms differ depending on the situation and problems in which they are used. These parts are usually the objective function (transformation), and their definition significantly affects the efficiency of the algorithm. By mode of action, genetic algorithms are among the methods directed random search space solutions are looking for a global optimum.
Supermassive Black Hole Binaries: The Search Continues
Tamara Bogdanovic
Physics , 2014, DOI: 10.1007/978-3-319-10488-1_9
Abstract: Gravitationally bound supermassive black hole binaries (SBHBs) are thought to be a natural product of galactic mergers and growth of the large scale structure in the universe. They however remain observationally elusive, thus raising a question about characteristic observational signatures associated with these systems. In this conference proceeding I discuss current theoretical understanding and latest advances and prospects in observational searches for SBHBs.
ESB-Based Sensor Web Integration for the Prediction of Electric Power Supply System Vulnerability
Leonid Stoimenov,Milos Bogdanovic,Sanja Bogdanovic-Dinic
Sensors , 2013, DOI: 10.3390/s130810623
Abstract: Electric power supply companies increasingly rely on enterprise IT systems to provide them with a comprehensive view of the state of the distribution network. Within a utility-wide network, enterprise IT systems collect data from various metering devices. Such data can be effectively used for the prediction of power supply network vulnerability. The purpose of this paper is to present the Enterprise Service Bus (ESB)-based Sensor Web integration solution that we have developed with the purpose of enabling prediction of power supply network vulnerability, in terms of a prediction of defect probability for a particular network element. We will give an example of its usage and demonstrate our vulnerability prediction model on data collected from two different power supply companies. The proposed solution is an extension of the GinisSense Sensor Web-based architecture for collecting, processing, analyzing, decision making and alerting based on the data received from heterogeneous data sources. In this case, GinisSense has been upgraded to be capable of operating in an ESB environment and combine Sensor Web and GIS technologies to enable prediction of electric power supply system vulnerability. Aside from electrical values, the proposed solution gathers ambient values from additional sensors installed in the existing power supply network infrastructure. GinisSense aggregates gathered data according to an adapted Omnibus data fusion model and applies decision-making logic on the aggregated data. Detected vulnerabilities are visualized to end-users through means of a specialized Web GIS application.
RC4 stream cipher and possible attacks on WEP
Lazar Sto?ic,Milena Bogdanovic
International Journal of Advanced Computer Sciences and Applications , 2012,
Abstract: In this paper we analyze and present some weaknesses and possible attacks on the RC4 stream cipher which were published in many journals. We review some advantages and disadvantages which come from several authors, as well as similarities and differences which can be observed in the published results. Also, we analyze the Key Scheduling Algorithm (KSA) which derives the initial state from a variable size key, and strengths and weaknesses of the RCS stream cipher. Using examples from other papers, we show that RC4 is completely insecure in a common mode of operation which is used in the widely deployed Wired Equivalent Privacy protocol (WEP, which is part of the 802.11 standard)
Tidal disruption of a star in the Schwarzschild spacetime: relativistic effects in the return rate of debris
Roseanne M. Cheng,Tamara Bogdanovic
Physics , 2014, DOI: 10.1103/PhysRevD.90.064020
Abstract: Motivated by an improved multi-wavelength observational coverage of the transient sky, we investigate the importance of relativistic effects in disruptions of stars by non-spinning black holes (BHs). This paper focuses on calculating the ballistic rate of return of debris to the black hole as this rate is commonly assumed to be proportional to the light curve of the event. We simulate the disruption of a low mass main sequence star by BHs of varying masses ($10^5,10^6,10^7 M_\odot$) and of a white dwarf by a $10^5 M_\odot$ BH. Based on the orbital energy as well as angular momentum of the debris, we infer the orbital distribution and estimate the return rate of the debris following the disruption. We find two signatures of relativistic disruptions: a gradual rise as well as a delayed peak in the return rate curves relative to their Newtonian analogs. Assuming that the return rates are proportional to the light curves, we find that relativistic effects are in principle measurable given the cadence and sensitivity of the current transient sky surveys. Accordingly, using a simple model of a relativistic encounter with a Newtonian parametric fit of the peak leads to an overestimate in the BH mass by a factor of $\sim {\rm few}\times0.1$ and $\sim {\rm few}$ in the case of the main sequence star and white dwarf tidal disruptions, respectively.
Paradoxical prosopagnosia in semantic dementia  [PDF]
Sven-Erik Fernaeus, Per Ostberg, Lars-Olof Wahlund, Nenad Bogdanovic
Advances in Alzheimer's Disease (AAD) , 2012, DOI: 10.4236/aad.2012.13008
Abstract: Objective: To study episodic and semantic memory for faces and other non-verbal information in semantic dementia (SD). Background: Semantic memory impaired in the rare diagnosis of SD by definition, including knowledge about well- known persons and their appearance. Episodic memory is held to be better preserved. Methods: Two computerized face recognition tests were administered, one measuring episodic memory (Male Faces) and one semantic memory (Political Faces) in addition to a comprehensive test battery. A computerised test of non-verbal semantic memory for national symbols (Euro Flags) was also administered druring the retention interval of the Male Faces test. Results: The SD participants were severely impaired in the episodic face recognition test. In contrast, their performance was in the normal range in Euro Flags and Political Faces, based on knowledge of national political figures. Conclusion: The results are discussed in terms of preserved dynamic memory and severely impaired memory for static facial information in semantic dementia. Research proposals regarding further studies of this paradoxical prosopagnosia in semantic dementia are presented in order to clarify issues regarding static versus dynamic aspects of face memory.
Mining method selection by integrated AHP and PROMETHEE method
Bogdanovic, Dejan;Nikolic, Djordje;Ilic, Ivana;
Anais da Academia Brasileira de Ciências , 2012, DOI: 10.1590/S0001-37652012000100023
Abstract: selecting the best mining method among many alternatives is a multicriteria decision making problem. the aim of this paper is to demonstrate the implementation of an integrated approach that employs ahp and promethee together for selecting the most suitable mining method for the "coka marin" underground mine in serbia. the related problem includes five possible mining methods and eleven criteria to evaluate them. criteria are accurately chosen in order to cover the most important parameters that impact on the mining method selection, such as geological and geotechnical properties, economic parameters and geographical factors. the ahp is used to analyze the structure of the mining method selection problem and to determine weights of the criteria, and promethee method is used to obtain the final ranking and to make a sensitivity analysis by changing the weights. the results have shown that the proposed integrated method can be successfully used in solving mining engineering problems.
PORHYROMONAS GINGIVALIS AND ACUTE MYOCARDIAL INFARCTION
Ivana Burazor,Aristo Vojdani,Dragan Bogdanovic
Acta Facultatis Medicae Naissensis , 2006,
Abstract: The classic dental disease, caries and periodontal disease might have an effect on systemic health. These diseases result from infections by microbes with highly specific adhesion mechanisms in the mouth. Over the last decade, accumulating evidences have linked dental infections to an increased risk of atherosclerosis and thrombosis. The aim of our study was to investigate whether Porhyromonas gingivalis might play a role in the development of acute myocardial infarction (AIM) as well as its possible relation with traditional risk factors.The study enrolled 124 participants, 74 of whom were patients with AIM (63 years old, 44 males) and 50 were controls (60.3 years old, 31 males). Blood was sampled and sent on dry ice to Immunosciences Lab Inc (USA).We determined circulating levels of IgG antibodies against Porhyromonas gingivalis by using the ELISA method. A high proportion of patients had circulating levels of IgG antibodies against Porhyromonas gingivalis above the reference range (98% vs 22%, P <0.001). The titers were significantly higher in patients compared to controls (P<0.001). Circulating concentrations of antibodies were higher in men and smokers. The higher the titers, the higher the monocytes and white blood cells count. In view of our results, patients with AIM have evidence of chronic infection caused by Porhyromonas gingivalis. Chronic dental infection could be considered as an independent risk for atherosclerotic disease.
HEALTH NEEDS
Cedomir Sagric,Olivera Radulovic,Marjana Bogdanovic
Acta Medica Medianae , 2007,
Abstract: Human needs are of great interest to different scientific fields: sociology, anthropology, psychology, medicine, economy… Malinowski, Maslow, Adler and From have largely contributed to studying the needs. While trying to define the need concept, not only one definition is acceptable. In psychology, need is defined as a lack or disorder, i.e. the necessity to dislodge this lack. It was Maslow who gave the fullest classification and explanation of human needs. If we start from the fact that need represents the lack or deficit of something, in this context health needs would indicate the lack of health, and the measurement of health needs would be the same as the measurement of health. Therefore, almost all human needs can be enumerated as health needs, i.e. those which, after being satisfied, can lead to physical, psychical and social welfare. According to WHO, health needs can be defined as scientifically settled evasions from health which require preventive, curative and probably regulative and eradicative measurements. According to the medical method used by the health service while regarding the needs, the emphasis is on morbidity, mortality, incidence, prevalence, inability, etc. Usually, when we have very low level of health culture, and the responsibility for personal health is in most of the cases unacceptable, for the health service user the curative services will have priority over preventive ones. The measurement of health needs is a complex task. The needs can be regarded through medical documentation and by perception of the needs by people in the community.
Using Faraday Rotation to Probe MHD Instabilities in Intracluster Media
Tamara Bogdanovic,Christopher Reynolds,Richard Massey
Physics , 2010, DOI: 10.1088/0004-637X/731/1/7
Abstract: It has recently been suggested that conduction-driven magnetohydrodynamic (MHD) instabilities may operate at all radii within an intracluster medium (ICM), and profoundly affect the structure of a cluster's magnetic field. Where MHD instabilities dominate the dynamics of an ICM, they will re-orient magnetic field lines perpendicular to the temperature gradient inside a cooling core, or parallel to the temperature gradient outside it. This characteristic structure of magnetic field could be probed by measurements of polarized radio emission from background sources. Motivated by this possibility we have constructed 3-d models of a magnetized cooling core cluster and calculated Faraday rotation measure (RM) maps in the plane of the sky under realistic observing conditions. We compare a scenario in which magnetic field geometry is characterized by conduction driven MHD instabilities to that where it is determined by isotropic turbulent motions. We find that future high-sensitivity spectro-polarimetric measurements of RM, such as will be enabled by the Expanded Very Large Array and Square Kilometer Array can distinguish between these two cases with plausible exposure times. Such observations will test the existence of conduction-driven MHD instabilities in dynamically relaxed cooling core clusters. More generally, our findings imply that observations of Faraday RM should be able to discern physical mechanisms that result in qualitatively different magnetic field topologies, without a priori knowledge about the nature of the processes.
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