2,717 research outputs found

    IP traceback with deterministic packet marking DPM

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    In this dissertation, a novel approach to Internet Protocol (IP) Traceback - Deterministic Packet Marking (DPM) is presented. The proposed approach is scalable, simple to implement, and introduces no bandwidth and practically no processing overhead on the network equipment. It is capable of tracing thousands of simultaneous attackers during a Distributed Denial of Service (DDoS) attack. Given sufficient deployment on the Internet, DPM is capable of tracing back to the slaves for DDoS attacks which involve reflectors. Most of the processing is done at the victim. The traceback process can be performed post-mortem, which allows for tracing the attacks that may not have been noticed initially or the attacks which would deny service to the victim, so that traceback is impossible in real time. Deterministic Packet Marking does not introduce the errors for the reassembly errors usually associated with other packet marking schemes. More than 99.99% of fragmented traffic will not be affected by DPM. The involvement of the Internet service providers (ISP) is very limited, and changes to the infrastructure and operation required to deploy DPM are minimal. Deterministic Packet Marking performs the traceback without revealing the internal topology of the provider\u27s network, which is a desirable quality of a traceback scheme

    Finding an optimal strategy of incorporating renewable sources of energy and electricity storing systems in a regional electrical grid

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    A game with a finite (more than three) number of players on a polyhedron of connected player strategies is studied. This game describes the interaction among (a) the base load power plant (the generator), (b) all the large customers of a regional electrical grid that receive electric energy from the generator, as well as from the available renewable sources of energy, both directly and via electricity storing facilities, and (c) the transmission company. An auxiliary three-person game on polyhedra of disjoint player strategies that is associated with the initial game is also considered. It is shown that an equilibrium point in the auxiliary game is an equilibrium point in the above game with connected player strategies. Verifiable necessary and sufficient conditions of an equilibrium in the auxiliary three-person game are proposed, and these conditions allow one to find equilibria in (the auxiliary) solvable game by solving three linear programming problems two of which form a dual pair

    Three Quantitative Management Problems in Public Procurement and Decision Procedures for their Analysis and Solving

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    Three management problems that a state (or a public administration acting on its behalf) faces in procuring goods and/or services are considered: a) choosing the type of a contract to be awarded and the type of a competitive bidding to determine the winning bid, b) setting the initial price for a contract being the subject of the bidding, and c) designing (or choosing) a set of rules for determining the winning bid by means of the chosen competitive bidding. Mathematical models and decision procedures for analyzing and solving these problems are discussed

    A game-theoretic approach to optimizing the scale of incorporating renewable sources of energy and electricity storing systems in a regional electrical grid

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    The problem of developing a decision support system for estimating a) the scale of incorporating available renewable sources of energy (such as solar and wind energy) in a part of a country’s electrical grid (called a regional electrical grid further in this paper), and b) the scale of storing electricity in this (regional) electrical grid to make these renewable sources of electric power competitive with traditional power generators (such as fossil-fuel and nuclear ones) and to reduce the cost of acquiring electricity from all the electric power generating facilities in the grid is considered. In the framework of this system, renewable sources of energy are viewed as electricity generating facilities under both existing and expected electricity prices, and the uncertainty of energy supply from them and the uncertainty of the grid customer demand for electricity during every 24 h are taken into account. A mathematical model underlying the system allows one to study the interaction of all the grid elements as a game with a finite (more than three) number of players on a polyhedron of connected player strategies (i.e., strategies that cannot be chosen by the players independently of each other) in a finite-dimensional space. It is shown that solving both parts of the problem under consideration is reducible to finding Nash equilibrium points in this game

    The Good, the Bad, and the Ugly: Three Proposals to Introduce the Nationwide Popular Vote in U.S. Presidential Elections

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    The idea of reforming the Electoral College recurs each time a presidential election nears. Polls show that an overwhelming majority of respondents support abolishing the Electoral College in favor of direct popular election of the President. Yet, it is doubtful whether these polls really imply that such a move would be best for the country. Despite the seeming simplicity of direct popular presidential election, its introduction in the United States—a country in which the clear separation of powers between the states and the federal government has existed for more than two centuries—would have hidden drawbacks that the media and pollsters usually fail to communicate. Further, the existing Electoral College-based system of electing a President is complicated, and the simplistic media coverage of American social and political phenomena fails to educate voters about the nuances of that system. Thus, pollsters are asking people whether they favor replacing the Electoral College, a system that many respondents don’t sufficiently understand, with direct popular election, a system that many respondents also don’t necessarily understand

    The Effect of Achievement Goals on Self-Explanation and Transfer: Investigating the Role of Motivation on Learning

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    The role of student motivation in learning is an important issue for research to address, both for theoretical and practical purposes. The present research study tested a hypothesized behavioral pathway for previously documented benefits of student motivation – in particular, mastery-approach achievement goals – on learning and transfer (Belenky & Nokes-Malach, 2012). Achievement goals are the reasons students have for engaging in academic settings, such as wanting to develop their competence (mastery-approach goal), wanting to do better than their peers (performance-approach goal), or not wanting to do any worse than their peers (performance-avoidance goal). The present study manipulated achievement goals (mastery-approach, performance-approach, or performance-avoidance) that participants adopted while learning, and subsequently being tested on, basic statistical knowledge and procedures. It was predicted that mastery-approach goals would lead to higher levels of knowledge transfer. Additionally, talk aloud protocols were collected and coded to test hypothesis that mastery-approach goals would lead to more constructive learning processes, such as self-explanation. Finally, it was expected that the degree of self-explanations a student engaged in would be predictive of transfer. These hypotheses were not supported. Contrary to expectations, the performance-avoidance condition produced higher levels of transfer than the mastery-approach condition. Additionally, there were no differences between conditions in the amount of self-explanations generated. The amount of self-explanations was itself not predictive of transfer. These results are discussed in terms of possible ways the methodology may have reduced the difficulty of transfer, as well as what the results may mean for achievement goal theory, more broadly

    The Good, the Bad, and the Ugly: Three Proposals to Introduce the Nationwide Popular Vote in U.S. Presidential Elections

    Get PDF
    The idea of reforming the Electoral College recurs each time a presidential election nears. Polls show that an overwhelming majority of respondents support abolishing the Electoral College in favor of direct popular election of the President. Yet, it is doubtful whether these polls really imply that such a move would be best for the country. Despite the seeming simplicity of direct popular presidential election, its introduction in the United States—a country in which the clear separation of powers between the states and the federal government has existed for more than two centuries—would have hidden drawbacks that the media and pollsters usually fail to communicate. Further, the existing Electoral College-based system of electing a President is complicated, and the simplistic media coverage of American social and political phenomena fails to educate voters about the nuances of that system. Thus, pollsters are asking people whether they favor replacing the Electoral College, a system that many respondents don’t sufficiently understand, with direct popular election, a system that many respondents also don’t necessarily understand

    Positive exchange bias in ferromagnetic La0.67Sr0.33MnO3 / SrRuO3 bilayers

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    Epitaxial La0.67Sr0.33MnO3 (LSMO)/ SrRuO3 (SRO) ferromagnetic bilayers have been grown on (001) SrTiO3 (STO) substrates by pulsed laser deposition with atomic layer control. We observe a shift in the magnetic hysteresis loop of the LSMO layer in the same direction as the applied biasing field (positive exchange bias). The effect is not present above the Curie temperature of the SRO layer (), and its magnitude increases rapidly as the temperature is lowered below . The direction of the shift is consistent with an antiferromagnetic exchange coupling between the ferromagnetic LSMO layer and the ferromagnetic SRO layer. We propose that atomic layer charge transfer modifies the electronic state at the interface, resulting in the observed antiferromagnetic interfacial exchange coupling.Comment: accepted to Applied Physics Letter

    Effects of Scheduling on Sleep and Performance in Commercial Motorcoach Operations

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    Maintaining cognitive alertness during commercial motorcoach operations is important for drivers as they are responsible for preventing, detecting, and managing errors. Schedules that do not follow circadian and homeostatic sleep principles may contribute to fatigue related events and accidents. The Federal Motor Carrier Safety Administration (FMCSA) has hoursof-service (HOS) regulations in place that allow motorcoach operators to work backwardly rotating 18-23 hour duty cycles (a duty cycle being the sum of HOS mandated on and off duty periods), requiring progressively earlier start times. Such schedules do not allow for sufficient and appropriately placed rest periods, resulting in fatigue and decreased performance. This study will investigate the effect of scheduling on sleep and performance in motorcoach operators. We are collecting objective and subjective data on sleep and performance of motorcoach drivers working under the current HOS regulations to observe the prevalence of circadian friendly and mismatched schedules, and the impact work schedules have on sleep and performance. This article describes the study design and methodology
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