Designed-in security for cyber-physical systems

An expert from academia, one from a cyber-physical system (CPS) provider, and one from an end asset owner and user offer their different perspectives on the meaning and challenges of 'designed-in security.' The academic highlights foundational issues and talks about emerging technology that can help us design and implement secure software in CPSs. The vendor's view includes components of the academic view but emphasizes the secure system development process and the standards that the system must satisfy. The user issues a call to action and offers ideas that will ensure progress

Drosophila piRNA Function in Genome Maintenance, Telomere Protection and Genome Evolution: A Dissertation

Upon fertilization, the early embryo sustains most of the cellular processes using the maternally deposited reserves in the egg itself until the zygotic gene expression takes charge. Among the plethora of essential components provided by the mother are small non-coding RNAs called PIWI-interacting RNAs (piRNAs), which provide immunity to the zygote against transposon challenge. In this thesis, I have presented three different functions of piRNAs in Drosophila melanogaster- in maintenance of genomic integrity, telomere protection and their role as an adaptive immune system against genomic parasites. In Chapter 2, I have described the phenotypic effects of the loss of piRNA function in early embryos. The mutations affecting the piRNA pathway are known to cause embryonic lethality. To describe this lethality in detail, I have shown that all the characterized piRNA mutants show compromised zygotic genomic integrity during early embryogenesis. In addition, two piRNA pathway components, Aubergine (Aub) and Armitage (Armi) are also required for telomere resolution during early embryogenesis. Aub and Armi recruit telomeric protection complex proteins, HOAP and HP1, to the telomeric ends and thus avoid activation of the Non-homologous end joining (NHEJ) DNA repair pathway at the telomeres. There are about 120 transposon families in Drosophila melanogaster and piRNA pathway mutations cause activation of many of the resident transposons in the genome. In Chapter 3, I have described the effects of infection by a single transposon, P-element, in naïve strains by introduction through the zygote. Activation of the P-element leads to desilencing of unrelated transposons, causing accumulation of germline DNA damage which is linked to severely reduced fertility in the hybrid females. However, there is partial restoration of fertility as the hybrid progeny age, which correlates with P-element piRNA production and thus P-element silencing. Additionally, a number of transposons mobilize into piRNA generating heterochromatic clusters in the genome, and these insertions are stably inherited in the progeny. Collectively our data shows that piRNA production can be triggered in the adults in an absence of maternal contribution and that piRNAs serve as an adaptive immune system which helps resolve an internal genetic conflict between the host and the parasite. In an effort to understand the phenotypic effects of piRNA dysfunction in Drosophila, we have uncovered new exciting roles for piRNAs in development and presented evidence how transposons can act as architects in restructuring the host genome

Mandatory Adoption of IFRS and Analysts’ Forecasts Information Properties

This study examines the properties of the information contained in analysts’ earnings forecasts for mandatory IFRS adopters in Europe for the period 2003-07. We find a significant increase in the precision of both public and private information after switching to IFRS, especially for forecasts pertaining to 2006 and later. However, we are unable to detect a change in the consensus among financial analysts after the mandatory adoption of IFRS. These results suggest that the higher percentage increase in the precision of common information is offset by a proportionate increase in the precision of private information such that consensus among analysts does not change. When exploring analyst-specific precision in more detail, we find that the analysts who are following firms in more than one European country experience the largest post-IFRS improvement in private information precision. These results hold after controlling for factors that are shown in prior research to be correlated with analysts’ information precision measures. Taken together, our results suggest that mandatory adoption of IFRS had a significant and positive effect on the information processing of financial analysts but this did not occur homogeneously across analysts.IFRS;mandatory IFRS adoption;analyst forecasts;information environment

Mandatory IFRS Reporting and Stock Price Informativeness

In this paper, we examine whether mandatory adoption of IFRS influences the flow of firm-specific information and contributes to stock price informativeness as measured by stock return synchronicity. Using a constant sample of 1,904 mandatory IFRS adopters in 14 EU countries for the period 2003-2007, we find a V-shaped pattern in synchronicity around IFRS adoption, which is consistent with IFRS disclosures revealing new firm-specific information in the adoption period (i.e., a reduction of synchronicity) and subsequently lowering the surprise of future disclosures (i.e., an increase in synchronicity). We also find mandatory IFRS adoption increases analysts’ ability to incorporate industry-level information into stock price. However, we are unable to detect a reduction in the private information advantage enjoyed by institutional owners post-IFRS adoption. Moreover, we find the synchronicity effects to be more pronounced for firms in countries with larger differences in local GAAP relative to IFRS. Overall, our evidence yields novel insights on the consequences of mandatory IFRS adoption by investigating its effect on stock price informativeness and the distinctive roles played by a firm’s information environment.IFRS;mandatory adoption;stock return synchronicity;information environment

Conductivity of interacting spinless fermion systems via the high dimensional approach

Spinless fermions with repulsion are treated non-perturbatively by classifying the diagrams of the generating functional $\Phi$ in powers of the inverse lattice dimension $1/d$. The equations derived from the first two orders are evaluated on the one- and on the two-particle level. The order parameter of the AB-charge density wave (AB-CDW) occurring at larger interaction is calculated in $d=3$. The Bethe-Salpeter equation is evaluated for the conductivity \sigma(\om) which is found to have two peaks within the energy gap $2\Delta$ in the AB-CDW: a remnant of the Drude peak and an excitonic resonance. Unexpectedly, $\sigma_{\rm\scriptscriptstyle DC}$ does not vanish for $T\to 0$Comment: Latex, 4 page