PeerHunter: Detecting Peer-to-Peer Botnets through Community Behavior Analysis

Peer-to-peer (P2P) botnets have become one of the major threats in network security for serving as the infrastructure that responsible for various of cyber-crimes. Though a few existing work claimed to detect traditional botnets effectively, the problem of detecting P2P botnets involves more challenges. In this paper, we present PeerHunter, a community behavior analysis based method, which is capable of detecting botnets that communicate via a P2P structure. PeerHunter starts from a P2P hosts detection component. Then, it uses mutual contacts as the main feature to cluster bots into communities. Finally, it uses community behavior analysis to detect potential botnet communities and further identify bot candidates. Through extensive experiments with real and simulated network traces, PeerHunter can achieve very high detection rate and low false positives.Comment: 8 pages, 2 figures, 11 tables, 2017 IEEE Conference on Dependable and Secure Computin

Berry Phase Effects on Electronic Properties

Ever since its discovery, the Berry phase has permeated through all branches of physics. Over the last three decades, it was gradually realized that the Berry phase of the electronic wave function can have a profound effect on material properties and is responsible for a spectrum of phenomena, such as ferroelectricity, orbital magnetism, various (quantum/anomalous/spin) Hall effects, and quantum charge pumping. This progress is summarized in a pedagogical manner in this review. We start with a brief summary of necessary background, followed by a detailed discussion of the Berry phase effect in a variety of solid state applications. A common thread of the review is the semiclassical formulation of electron dynamics, which is a versatile tool in the study of electron dynamics in the presence of electromagnetic fields and more general perturbations. Finally, we demonstrate a re-quantization method that converts a semiclassical theory to an effective quantum theory. It is clear that the Berry phase should be added as a basic ingredient to our understanding of basic material properties.Comment: 48 pages, 16 figures, submitted to RM

Global Agrifood Value Chains and Local Poverty Reduction: What Happens to Those Who Don’t Plug In?

Structural changes in the global agrifood value chain have transformed food production in developing countries including Indonesia. One element of this is the spread of supermarket retailing. By increasing the demand for and returns to higher quality produce, this development has the potential to improve living standards in a sector where poverty has been persistent. Many studies have shown the magnitude of price premiums available to farmers who sell to supermarkets. However, little attention has been paid to how the introduction of a supermarket retailer affects those farmers who continue to sell to traditional market channels. Our data suggests that in regions where there are both modern and traditional buyers, competition effects result in the immiserization of farmers who continue to sell to traditional markets. This result underlines the fact that while sectorial transformation has desirable poverty reduction potential, actual impacts are lumpy. The distribution of farmer participation in a region may result in a case where the upgrading of agrifood supply chains can increase poverty in the absence of policy interventions

Theory of local heating in nanoscale conductors

We report first-principles calculations of local heating in nanoscale junctions formed by a single molecule and a gold point contact. Due to a larger heat dissipation, the single molecule heats up less than the gold point contact. We also find, at zero temperature, a threshold bias $V_{onset}$ of about 6 mV and 11 mV for the molecule and the point contact, respectively, is required to excite the smallest vibrational mode and generate heat. The latter estimate is in very good agreement with recent experimental results on the same system. At a given external bias $V$ below $V_{onset}$, heating becomes noticeable when the background temperature is on the order of $\sim e(V_{onset}-V)/k_{B}$. Above $V_{onset}$, local heating increases dramatically with increasing bias but is also considerably suppressed by thermal dissipation into the electrodes. The results provide a microscopic picture of current-induced heat generation in atomic-scale structures.Comment: 4 pages, 4figure

Inelastic effects on the transport properties of alkanethiols

Using first-principles approaches we investigate local heating and the inelastic contribution to the current for various alkanethiols sandwiched between metal electrodes. In the absence of good heat dissipation into the bulk electrodes, we find that the local temperature of the alkanethiols is relatively insensitive to their length. This is due to the rates of heating and cooling processes scaling similarly with length. On the other hand, when considering heat dissipation into the bulk electrodes, the local temperature of alkanethiols decreases as their length increases. We also find that the inelastic scattering profile displays an odd-even effect with length which compares well with experimental results. This effect is due to the alternating direction of the CH3 group motion with respect to current flow with increasing C atoms in the chain, and is very sensitive to the structure of the carbon-sulfur-gold bond. Inelastic scattering profiles can therefore help illuminate the bonding configuration of molecules to metallic surfaces.Comment: 5 pages, 4 figure