A key motivation for transparency regulations and disclosure rules is the view that corporations are more opaque than they could be. Traditional arguments attribute this tendency to agency problems between managers on one side and stakeholders and/or outsiders on the other. We propose a completely di erent argument for why corporations limit the ow of information. When secondary markets are sha...

Several types of variable stars are found along the HR diagram whose pulsations are driven by the κ-mechanism. Given their nature, the precise (Teff − L) domain where these pulsators are located is highly dependent on the value of opacity and on its variation inside the star. We analyze the sensitivity of opacity driven pulsators of spectral-type A and B (δ Scuti, β Cephei and SPB stars) to the...

In this paper we introduce two families of safety properties: ♦-opacity and ♦linearizability. The new properties relax to various degree the real-time order requirement on transaction execution in opacity and, analogically, the real-time order requirement on operation execution in linearizability. This way we can formalize the guarantees provided by a wide class of strongly consistent replicate...

It is important to quantify the atmospheric opacity at the VLA in order to aid in interpretation of data taken at high frequencies. In addition, in the near future it is envisioned that dynamic scheduling will be used in order to select observing programs. Atmospheric opacity will be an important input parameter into dynamic scheduling. In the absence of a dedicated instrument to measure the at...

We study the enforcement of K-step opacity at runtime. In K-step opacity, the knowledge of the secret is of interest to the attacker within K steps after the secret occurs and becomes obsolete afterwards. We introduce the mechanism of runtime enforcer that is placed between the output of the system and the attacker and enforces opacity using delays. If an output event from the system violates K...

We present a new method for computing shadows from semitransparent objects like hair. Extending the concept of opacity shadow maps, the deep opacity map method uses a depth map to obtain a per pixel distribution of opacity layers. This approach totally eliminates the layering artifacts of opacity shadow maps and requires much fewer layers to achieve high quality shadow computation. We provide q...

Serotypings have been used as markers for epidemiological surveys of Streptococcus pyogenes infections. Seventy-seven strains of S. pyogenes isolated from the throats of elementary school children in Kangwon Province in Korea in March and April 1992 were serotyped with M and/or opacity factor (OF) antisera. Sixty-eight strains of S. pyogenes from healthy school children in Chungnam Province in ...

In this paper we extend the notion of opacity, defined for discrete-event systems, to dense-time systems. We define the timed opacity problem for timed automata and study its algorithmic status. We show that for the very restrictive class of Event Recording Timed Automata, the opacity problem is already undecidable leaving no hope for an algorithmic solution to the opacity problem in dense-time.

Despite recent major advances, the opacity remains a source of substantial uncertainty in the calculation of solar models, and hence of solar oscillation frequencies. Hence it is of substantial interest to investigate the sensitivity of solar structure to changes in the opacity. Furthermore, we may hope from the precise helioseismic inferences of solar structure to obtain information about poss...

Despite recent major advances, the opacity remains an important source of uncertainty in the calculation of solar models, and hence of solar oscillation frequencies. Hence it is of substantial interest to investigate the sensitivity of solar structure to changes in the opacity. Furthermore, we may hope from the precise helioseismic inferences of solar structure to obtain information about possi...