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No description available.

No / A two-tiered architecture with resource-rich master nodes at the upper tier and resource-poor sensor nodes at the lower tier is expected to be adopted in large scale sensor networks. In a hostile environment, adversaries are more motivated to compromise the master nodes to break the authenticity and completeness of query results, whereas it is lack of light and secure query processing protocol in tiered sensor networks at present. In this paper, we study the problem of verifiable fine-grained top- queries in two-tiered sensor networks, and propose a novel verification scheme, which is named Verification Scheme for Fine-grained Top- Queries (VSFTQ). To make top- query results verifiable, VSFTQ establishes relationships among data items of each sensor node using their orders, which are encrypted together with the scores of the data items and the interested time epoch number using distinct symmetric keys kept by each sensor node and the network owner. Both theoretical analysis and simulation results show that VSFTQ can not only ensure high probability of detecting forged and/or incomplete query results, but also significantly decrease the amount of verification information when compared with existing schemes.

Proceeding from a specification, one develops an abstract mathematical model of a system, or portion of a system. This model of a system is validated to insure that the specification is interpreted accurately and to explore different algorithms for implementing the system behavior. We use the words "portion of a system," because only rarely are systems designed wholly using a purely top-down approach. Commonly, the design approach is a mixture of top-down and bottom-up. But even in this mixed approach, top-down techniques are critical to the development of new, advanced system features and improving the performance of existing system components. An example of this style of design tools and environments is Ptolemy II. Ptolemy II is a high-level modeling tool created at UC-Berkeley. It supports heterogeneous and homogeneous modeling, simulation, and design of concurrent systems. High-level modeling of such embedded systems as digital electronics, hardware, and software can be effectively represented. The bottom-up design approach exploits design reuse to achieve the productivity necessary to build complex systems. Historically, chip design companies have always reused designs in going from one product generation to another, but the efficiency of bottom-up design is enhanced by the use of IP (Intellectual Property) cores that a company can buy from an outside source. Design libraries are useful for system design and are an example of IP cores. A sound methodology to translate Ptolemy models to SystemC models would have a very beneficial effect on the CAD/EDA industry. Ptolemy II is written in Java and its high-level designs, or abstract graph models, are represented as XML documents. Ptolemy's major emphasis is on the methodology for defining and producing embedded software together with the system in which it is embedded. SystemC is written in C++, and its industrial use is gaining momentum due to its ability to represent functionality, communication, software, and hardware at various levels of abstraction. SystemC produces synthesizable code. A methodology to convert Ptolemy models to synthesizable SystemC code would be the technical epitome of a hybrid between top-down and bottom-up design styles and methodologies. Such a methodology would enable system designers to obtain fast design exploration, efficient IP-reuse, and validation. Ptolemy has various components and models of computation. A model of computation dictates how components interact between other components. SystemC has its own models of computation and design libraries. XML and Perl are both powerful tools by themselves, and we use these tools in this research to create a sound methodology for translating Ptolemy models (high-level of abstraction) to synthesizable SystemC code (low-level of abstraction), i.e.: code which can serve as input to hardware tools. / Ph. D.

We propose a framework for managing changes in Long term Composed Services (LCSs). The key components of the proposed framework include a Web Service Change Management Language (SCML), change enactment, and change optimization. The SCML is a formal language to specify top-down changes. It is built upon a formal model which consists of a Web service ontology and a LCS schema. The Web service ontology gives a semantic description on the important features of a service, including functionality, quality, and context. The LCS schema gives a high-level overview of a LCS's key features. A top-down change is specified as the modification of a LCS schema in the first place. Change enactment is the process of reacting to a top-down change. It consists of two subcomponents, including change reaction and change verification. The change reaction component implements the proposed change operators by modifying a LCS schema and the membership of Web services. The change verification component ensures that the correctness of a LCS is maintained during the process of change reaction. We propose a set of algorithms for the processes of change reaction and verification. The change optimization component selects the Web services that participate in a LCS to ensure that the change has been reacted to in the best way. We propose a two-phase optimization process to select services using both service reputation and service quality. We present a change management system that implements the proposed approaches. We also conduct a set of simulations to assess the performance. / Ph. D.

The red imported fire ant, Solenopsis invicta, is an abundant and aggressive component of early-successional communities in the southeastern United States. After disturbance, it rapidly invades new habitats, and once there, it has strong competitive and predatory effects on the existing arthropod community. In upland coastal plain pine forests at the Savannah River Site in South Carolina, I conducted two studies of fire ant ecology. In my first study (chapter 1), I investigated the way in which fire ants colonize early-successional road and powerline cuts through forests, and I tested whether some of these linear habitats provided better fire ant habitat than others. I found that fire ant mound density (#/ha) was similar in narrow dirt roads and in wider roads with the same intermediate level of mowing disturbance, and that density was lower in wide powerline cuts where the vegetation is only removed every five years. Furthermore, mound density was greatest near the edges of cleared roads and powerline cuts and was also greater on the northern sides of roads and powerline cuts where there was less shading from the adjacent forest. Results from this study suggest that allowing increased shading from adjacent forest vegetation, especially along northern roadside edges, would limit the suitability of road and powerline cuts as fire ant habitat, thereby slowing invasion. In my second study (chapter 2), I examined the impact of fire ants on arthropod and plant species in early-successional forest gaps. In a tritrophic system, I tested whether the top-down effect of insect herbivore consumption by fire ants was strong enough to cascade through two trophic levels and improve plant growth and fitness. I compared this potential effect to that of other arthropod predators in the community. I found that fire ants controlled the level of tissue damage to plant leaves by herbivores, but that the damage was not severe enough to influence plant growth or fitness. Fire ants had stronger negative interactions with insect herbivores than other predators in the community, and for this reason, fire ants can be considered keystone predators. This project provides further evidence that fire ants successfully invade even small patches of early-successional habitat that exist within larger matrices of uninhabitable, late-successional forest, and that once there, they have a dramatic effect on the arthropod community. Restricting the amount of early-successional habitat within southeastern forests, either as permanent road and powerline cuts or as temporary gaps, would limit the potential for strong and detrimental effects by the invasive fire ant. / Master of Science

<p>Menadžment predstavlja jednu od najaktuelnijih oblasti na&scaron;eg doba, mada je, pored svoje važnosti, jo&scaron; uvek nedovoljno istražen, u teorijskom i praktičnom smislu. Na osnovu dosada&scaron;njih istraživanja može se zaključiti da kvalitetan menadžment predstavlja temelj profitabilnog funkcionisanja svakog savremenog poslovnog sistema. Istraživanje, u doktorskoj disertaciji, je imalo za cilj da utvrdi ključne aktivnosti top menadžmenta u preduzećima u Bosni i Hercegovini.&nbsp; Potreba za ovim istraživanjem proizlazi iz neophodnosti utvrđivanja ključnih aktivnosti top menadžmenta, koje su važne za uspe&scaron;no funkcionisanje preduzeća. Na taj način će se obezbediti da top menadžment svoje aktivnosti i napore uvek fokusira u pravom smeru, kao i to da u svakom trenutku bude moguća provera efikasnosti rada top menadžmenta u nekom preduzeću. Ovakvo istraživanje ima dodatni značaj s obzirom na tranzicione uslove u Bosni i Hercegovini.</p> / <p>Management represents the most current area nowdays, although, aside from its immense importance, it has not been researched sufficiently, neither in theory nor in practice. Based upon all the previous research, it is possible to draw the conclusion that high-quality management is the foundation of every contemporaneous profit-oriented business system. The goal of this doctoral dissertation is to determine the essential activities of the top-management within the companies in Bosnia and Herzegovina. This determination will enable the top management to focus their efforts to head in the right direction, in order to be able to evaluate the efficiency of their work. Regarding the fact that Bosnia and Herzegovina is going through the transition period, this type of research gains additional importance.</p>

This thesis presents a search for resonant production of top-antitop quark pairs in final states containing at least one electron or muon. A number of beyond the standard model (BSM) theories incorporate a specific role for the top quark, resulting in resonances that preferentially decay to t(bar over t) pairs. The data sample analysed corresponds to an integrated luminosity of 2.05 fb^-1 recorded during 2011 using the ATLAS detector at the Large Hadron Collider. The proton-proton centre-of-mass energy was 7 TeV. The search is tailored towards heavy resonances at the TeV-scale which therefore decay to top quarks with high transverse momentum. Large hadronic jets are used to reconstruct the energy carried by the hadrons and the substructure of these jets is studied in order to identify hadronically decaying top quarks. The reconstruction can therefore proceed even if the decay products of the top quark are highly collimated. This study represents the first use of jet substructure techniques in a search for t(bar over t) resonances using hadron-hadron collision data. The invariant mass of the reconstructed t(bar over t) pair is used to test compatibility of the data with the standard model prediction. No evidence for t(bar over t) resonances is found. Upper limits are derived on the production cross-section times branching ratio for narrow and wide resonant states, at the 95 % credibility level. An upper limit of 0.61 (0.65) pb is set for a narrow (wide) resonance with a mass of 1 TeV. Two specific BSM models are excluded within certain mass ranges: the narrow leptophobic Z' boson with mass 600 - 1150 GeV and the wide Kaluza-Klein gluon with a mass below 1.5 TeV. These results represent a significant improvement on those of previous searches performed at the ATLAS experiment, which did not use jet substructure techniques. In addition, the possibility of using jets which decrease in size as their transverse momentum increases is investigated using simulated data. The yield of events due to resonant t(bar over t) production increases by approximately 20 % compared to when using jets of fixed size. Furthermore, the resolution of the invariant mass of the reconstructed t(bar over t) pair is found to improve by almost one fifth. It is recommended that a calibration scheme be developed for these variable-sized jets, so that their potential to improve the sensitivity to t(bar over t) resonances can be investigated further.