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

What affects the freezing behaviors of cement-based porous materials: The role of the unfrozen liquid-like layer

A key factor that affects freeze-thaw damages of cement-based porous materials (CBPMs) is the amount of the freezable water confined in the pores that generate large internal pressures during freezing. Taking account of an unfrozen liquid-like layer (ULLL) between ice crystals and pore wall, this paper investigates deformations of a saturated CBPM specimen under freezing with different thickness values of the ULLL. To bridge the macro strains and the local pressure exerted on the pore wall of the material, the thermodynamic equilibrium between the water and ice, and a poroelastic approach were adopted. The hydraulic pressure by volume change as phase transition takes place in the pores, the fusion pressure by energy change as ice forms and penetrates through the thin pores and the hydrothermal pressure by TEC discrepancies between the pore fluids and solid substrate dominate the internal freezing stress. The obtained results reveal that the ULLL plays an important role on the estimation of the amount of ice crystals confined in the pores, and thus influences the pore pressures and deformations of the CBPM specimen used. Appropriate model of the ULLL helps to decrease the deviations between the predicted strains and the experimental data

Formation of Long Single Quantum Dots in High Quality InSb Nanowires Grown by Molecular Beam Epitaxy

We report on realization and transport spectroscopy study of single quantum dots (QDs) made from InSb nanowires grown by molecular beam epitaxy (MBE). The nanowires employed are 50-80 nm in diameter and the QDs are defined in the nanowires between the source and drain contacts on a Si/SiO$_2$ substrate. We show that highly tunable QD devices can be realized with the MBE-grown InSb nanowires and the gate-to-dot capacitance extracted in the many-electron regimes is scaled linearly with the longitudinal dot size, demonstrating that the devices are of single InSb nanowire QDs even with a longitudinal size of ~700 nm. In the few-electron regime, the quantum levels in the QDs are resolved and the Land\'e g-factors extracted for the quantum levels from the magnetotransport measurements are found to be strongly level-dependent and fluctuated in a range of 18-48. A spin-orbit coupling strength is extracted from the magnetic field evolutions of a ground state and its neighboring excited state in an InSb nanowire QD and is on the order of ~300 $\mu$eV. Our results establish that the MBE-grown InSb nanowires are of high crystal quality and are promising for the use in constructing novel quantum devices, such as entangled spin qubits, one-dimensional Wigner crystals and topological quantum computing devices.Comment: 19 pages, 5 figure