A Framework for Secure and Survivable Wireless Sensor Networks

Wireless sensor networks increasingly become viable solutions to many challenging problems and will successively be deployed in many areas in the future. A wireless sensor network (WSN) is vulnerable to security attacks due to the insecure communication channels, limited computational and communication capabilities and unattended nature of sensor node devices, limited energy resources and memory. Security and survivability of these systems are receiving increasing attention, particularly critical infrastructure protection. So we need to design a framework that provide both security and survivability for WSNs. To meet this goals, we propose a framework for secure and survivable WSNs and we present a key management scheme as a case study to prevent the sensor networks being compromised by an adversary. This paper also considers survivability strategies for the sensor network against a variety of threats that can lead to the failure of the base station, which represents a central point of failure.key management scheme, security, survivability, WSN

A general existence result for isothermal two-phase flows with phase transition

Liquid-vapor flows with phase transitions have a wide range of applications. Isothermal two-phase flows described by a single set of isothermal Euler equations, where the mass transfer is modeled by a kinetic relation, have been investigated analytically in (Quarterly of applied Mathematics, vol.\ LXXI 3 (2013), pp.\ 509-540.). This work was restricted to liquid water and its vapor modeled by linear equations of state. The focus of the present work lies on the generalization of the primary results to arbitrary substances, arbitrary equations of state and thus a more general kinetic relation. We prove existence and uniqueness results for Riemann problems. In particular, nucleation and evaporation are discussed

Snap Forensics: A Tradeoff between Ephemeral Intelligence and Persistent Evidence Collection

Digital evidence needs to be made persistent so that it can be used later. For citizen forensics, sometimes intelligence cannot or should not be made persistent forever. In this position paper, we propose a form of snap forensics by defining an elastic duration of evidence/intelligence validity. Explicitly declaring such a duration could unify the treatment of both ephemeral intelligence and persistent evidence towards more flexible storage to satisfy privacy requirements

Agree to Disagree: Security Requirements Are Different, But Mechanisms For Security Adaptation Are Not

We describe a dialogue between a proponent and an opponent of the proposition "security is not just another quality attribute in self-adaptive systems". The dialogue is structured in two steps. First, we examine whether security requirements are different from other system-level requirements. Our consensus is that security requirements require specific methods for elicitation, reasoning, and analysis. However, other requirements (such as safety, usability and performance) also require specific techniques. Then, we examine the adaptation mechanisms for security and compare them with other properties. Our consensus is that most adaptation techniques can be applied to maintain security and other requirements alike

Market Penetration of Biomass Fuels for Electricity Generation

The electric power sector is a main source of carbon dioxide (CO2) emissions that contribute to global warming. In the U.S., fossil fuel fired power plants are responsible for about 38% of the total CO2 emissions from all sources. Switching a significant portion of the U.S. electricity generating capacity from fossil fuels to biomass fuels would help reduce CO2 emissions from the electric power industries. At present, biomass accounts for only about 1% of the fuel used for electricity generation in the U.S. In contrast, coal alone accounts for about 50%, and nuclear, natural gas and petroleum explain for about 20%, 16% and 3% respectively of the fuels used for electricity generation. There are a number of factors that may influence the extent to which biomass fuels are to penetrate the electricity market: facility needs, growth in electricity demand, prices of fossil fuels and advances in technology. Electricity is generally produced in large, expensive and long-lived facilities. However new facilities or capitals are often built to meet demand growth. Capitals can be generally said to have a given productive lifetime. As new capital investment occurs and older capital is retired, electricity producers will have opportunities to substitute away from fossil fuels. Thus, an increase in the market penetration of biomass power will likely occur when existing fossil power plants are retired and replaced by new and less carbon intensive power plants. The market penetration of biomass electricity will also depend on a strong growth in electricity demand due to economic and population growth, availability and prices of fuels, environmental considerations and technological advances. Specifically, this paper will look at the potential for biomass penetration into the electricity market considering: a) prices of fossil fuels such as coal, natural gas and petroleum for power production, b) the capital turnover rate for existing stock of fossil power plants, c) changes in technologies which could facilitate the use of biomass as fuels for electricity generation.Resource /Energy Economics and Policy,

Numerical modeling of shape and topology optimisation of a piezoelectric cantilever beam in an energy-harvesting sensor

Piezoelectric materials are excellent transducers for converting mechanical energy from the environment for use as electrical energy. The conversion of mechanical energy to electrical energy is a key component in the development of self-powered devices, especially enabling technology for wireless sensor networks. This paper proposes an alternative method for predicting the power output of a bimorph cantilever beam using a finite-element method for both static and dynamic frequency analyses. A novel approach is presented for optimising the cantilever beam, by which the power density is maximised and the structural volume is minimised simultaneously. A two-stage optimisation is performed, i.e., a shape optimisation and then a “topology” hole opening optimisation

Quasi-continuous higher-order sliding-mode controllers for spacecraft-attitude-tracking manoeuvres

This paper studies higher order sliding-modecontrol laws to deal with some spacecraft-attitude-tracking problems. Quasi-continuous second- and third-order sliding controllers and differentiators are applied to quaternion-based spacecraftattitude- tracking maneuvers. A class of linear sliding manifolds is selected as a function of angular velocities and quaternion errors. The second method of Lyapunov is used to show that tracking is achieved globally. An example of multiaxial attitude-tracking maneuvers is presented, and simulation results are included to verify and compare the practical usefulness of the various controllers