Game Theory Meets Network Security: A Tutorial at ACM CCS

The increasingly pervasive connectivity of today's information systems brings up new challenges to security. Traditional security has accomplished a long way toward protecting well-defined goals such as confidentiality, integrity, availability, and authenticity. However, with the growing sophistication of the attacks and the complexity of the system, the protection using traditional methods could be cost-prohibitive. A new perspective and a new theoretical foundation are needed to understand security from a strategic and decision-making perspective. Game theory provides a natural framework to capture the adversarial and defensive interactions between an attacker and a defender. It provides a quantitative assessment of security, prediction of security outcomes, and a mechanism design tool that can enable security-by-design and reverse the attacker's advantage. This tutorial provides an overview of diverse methodologies from game theory that includes games of incomplete information, dynamic games, mechanism design theory to offer a modern theoretic underpinning of a science of cybersecurity. The tutorial will also discuss open problems and research challenges that the CCS community can address and contribute with an objective to build a multidisciplinary bridge between cybersecurity, economics, game and decision theory

Subaltern imaginaries of localism: constructions of place, space and democracy in community-led housing organisations.

The localism strategies of the UK government provide a suite of ‘rights’ for community organisations that licence place-based political imaginaries with the intent to construct the community as a proxy for a smaller state. Conflating place with participation and promising to devolve power, localism authorises a performative enactment of democracy, citizenship and the ‘public’ through the lived experience of space. In constituting the local as a metaphor for democracy and empowerment, however, community localism foregrounds the pivotal role played by place and scale in cementing social differentiation and in naturalising hierarchical power relations. This paper explores the subaltern strategies of localism that may emerge when the rights of localism are exercised by residents’ organisations in marginalised communities of social housing. Drawing on research with community-led housing organisations it demonstrates how the spatial imaginations and spatial practices of localism can be implemented to assert new claims on democracy and citizenship. In particular it identifies four spatial practices – the extension of domestic space, the invocation of locality, the construction of domestic scale, and the scalar reimagining of democracy – that subvert the reordering of political space that is localism’s regulatory intent

Strange attractors in periodically-kicked degenerate Hopf bifurcations

We prove that spiral sinks (stable foci of vector fields) can be transformed into strange attractors exhibiting sustained, observable chaos if subjected to periodic pulsatile forcing. We show that this phenomenon occurs in the context of periodically-kicked degenerate supercritical Hopf bifurcations. The results and their proofs make use of a new multi-parameter version of the theory of rank one maps developed by Wang and Young.Comment: 16 page

Numerical study of mach number effects in compressible wall-bounded turbulence

The aim of this work is to improve the present understanding of compressibility effects in wall-bounded turbulence and to provide data for improving models. A family of wall-bounded compressible flows has been investigated using direct numerical simulation (DNS). The research is divided into two aspects: a study of the intrinsic compressibility effects in isothermal-wall channel flow and a study of the impinging shock/turbulent boundary-layer interaction. For the channel flow, an energy sink is introduced in the energy equation to effectively eliminate the compressibility effects caused by mean-property variation, isolating the intrinsic compressibility effects induced by fluctuations of the density and temperature (and pressure, dilatation, etc) fields. Centreline Mach numbers, Mcl, up to 6.2 have been considered, for which we find that both explicit compressibility terms in the TKE equation such as the pressure-dilatation and dilatational dissipation, and the implicit compressibility such as Reynolds-stress-anisotropy tensor begin to become important. An oblique shock/turbulent boundary-layer interaction at free stream Mach number M ? = 2 is also investigated. Central to this work is the need to quickly obtain a fully developed turbulent boundary-layer over the shortest possible downstream distance, for which a quasi-deterministic inflow strategy is used. Then an oblique shock is impinged on to the fully developed turbulence boundary-layer and the flow separates. Explicit and implicit compressibility effects become important and the TKE budget is altered completely within the interaction zone. The interactions of shock with the separation bubble and the velocity are also addressed

Determination of anisotropic dipole moments in self-assembled quantum dots using Rabi oscillations

By investigating the polarization-dependent Rabi oscillations using photoluminescence spectroscopy, we determined the respective transition dipole moments of the two excited excitonic states |Ex> and |Ey> of a single self-assembled quantum dot that are nondegenerate due to shape anisotropy. We find that the ratio of the two dipole moments is close to the physical elongation ratio of the quantum dot.Comment: 11 pages, 2 figures, MS Word generated PDF fil

Vector meson photoproduction in the quark model

We present a quark model study of the $\omega$ meson photoproduction near threshold. With a limited number of parameters, all the data in history are reproduced. The roles played by the {\it s}- and {\it u}-channel processes (resonance excitations and nucleon pole terms), as well as the {\it t}-channel {\it natural} (Pomeron) and {\it unnatural} parity (pion) exchanges are clarified. This approach provides a framework for systematic study of vector meson photoproduction near threshold.Comment: 4 pages, 3 figures; Talk given at NSTAR2001, Mainz, Germany, Mar. 7-10, 200