Precise Enforcement of Progress-Sensitive Security

Program progress (or termination) is a covert channel that may leak sensitive information. To control information leakage on this channel, semantic definitions of security should be progress sensitive and enforcement mechanisms should restrict the channel's capacity. However, most state-of-the-art language-based information-flow mechanisms are progress insensitive---allowing arbitrary information leakage through this channel---and current progress-sensitive enforcement techniques are overly restrictive. We propose a type system and instrumented semantics that together enforce progress-sensitive security more precisely than existing approaches. Our system is permissive in that it is able to accept programs in which the termination behavior depends only on low-security (e.g., public or trusted) information. Our system is parameterized on a termination oracle, and controls the progress channel precisely, modulo the ability of the oracle to determine the termination behavior of a program based on low-security information. We have instantiated the oracle for a simple imperative language with a logical abstract interpretation that uses an SMT solver to synthesize linear rank functions. In addition, we extend the system to permit controlled leakage through the progress channel, with the leakage bound by an explicit budget. We empirically analyze progress channels in existing Jif code. Our evaluation suggests that security-critical programs appear to satisfy progress-sensitive security.Engineering and Applied Science

Declarative Policies for Capability Control

In capability-safe languages, components can access a resource only if they possess a capability for that resource. As a result, a programmer can prevent an untrusted component from accessing a sensitive resource by ensuring that the component never acquires the corresponding capability. In order to reason about which components may use a sensitive resource it is necessary to reason about how capabilities propagate through a system. This may be difficult, or, in the case of dynamically composed code, impossible to do before running the system. To counter this situation, we propose extensions to capability-safe languages that restrict the use of capabilities according to declarative policies. We introduce two independently useful semantic security policies to regulate capabilities and describe language-based mechanisms that enforce them. Access control policies restrict which components may use a capability and are enforced using higher-order contracts. Integrity policies restrict which components may influence (directly or indirectly) the use of a capability and are enforced using an information-flow type system. Finally, we describe how programmers can dynamically and soundly combine components that enforce access control or integrity policies with components that enforce different policies or even no policy at all.Engineering and Applied Science

Exact pressure evolution equation for incompressible fluids

An important aspect of computational fluid dynamics is related to the determination of the fluid pressure in isothermal incompressible fluids. In particular this concerns the construction of an exact evolution equation for the fluid pressure which replaces the Poisson equation and yields an algorithm which is a Poisson solver, i.e., it permits to time-advance exactly the same fluid pressure \textit{without solving the Poisson equation}% . In fact, the incompressible Navier-Stokes equations represent a mixture of hyperbolic and elliptic pde's, which are extremely hard to study both analytically and numerically. In this paper we intend to show that an exact solution to this problem can be achieved adopting the approach based on inverse kinetic theory (IKT) recently developed for incompressible fluids by Ellero and Tessarotto (2004-2007). In particular we intend to prove that the evolution of the fluid fields can be achieved by means of a suitable dynamical system, to be identified with the so-called Navier-Stokes (N-S) dynamical system. As a consequence it is found that the fluid pressure obeys a well-defined evolution equation. The result appears relevant for the construction of Lagrangian approaches to fluid dynamics.Comment: Contributed paper at RGD26 (Kyoto, Japan, July 2008

Observations of GRB 060526 Optical Afterglow with Russian-Turkish 1.5-m Telescope

We present the results of the photometric multicolor observations of GRB 060526 optical afterglow obtained with Russian-Turkish 1.5-m Telescope (RTT150, Mt. Bakirlitepe, Turkey). The detailed measurements of afterglow light curve, starting from about 5 hours after the GRB and during 5 consecutive nights were done. In addition, upper limits on the fast variability of the afterglow during the first night of observations were obtained and the history of afterglow color variations was measured in detail. In the time interval from 6 to 16 hours after the burst, there is a gradual flux decay, which can be described approximately as a power law with an index of -1.14+-0.02. After that the variability on the time scale \delta t < t is observed and the afterglow started to decay faster. The color of the afterglow, V-R=~0.5, is approximately the same during all our observations. The variability is detected on time scales up to \delta t/t =~ 0.0055 at \Delta F_\nu/F_\nu =~ 0.3, which violates some constraints on the variability of the observed emission from ultrarelativistic jet obtained by Ioka et al. (2005). We suggest to explain this variability by the fact that the motion of the emitting shell is no longer ultrarelativistic at this time.Comment: 6 pages, 7 figures, Astronomy Letters, 2007, 33, 797, The on-line data tables and the original text in Russian can be found at http://hea.iki.rssi.ru/grb/060526/indexeng.htm

Investigations on pests, diseases and present early warning system of apple orchards in Isparta, Turkey

As a result of three year surveys performed in the apple orchards in Isparta region, 19 pest species belonging to 4 orders were determined and it was found that the main pest was codling moth. Most of the predators and parasitoids were effective against aphids and they were mostly found in the orchards where selective pesticides were used. Apple scab and powdery mildew were the most common and important diseases. Biology of codling moth and apple scab in the region were investigated. By using the obtained data, proper application times were given and some recommendations regarding integrated pest management program in apple orchards, were summarized

Integrated diagnostic pathway for patients referred with suspected OSA: a model for collaboration across the primary-secondary care interface

BACKGROUND: Obstructive sleep apnoea (OSA) presents a major healthcare challenge with current UK data suggesting that only 22% of individuals have been diagnosed and treated. Promoting awareness and improving access to diagnostics are fundamental in addressing these missing cases and the recognised complications associated with untreated OSA. Diagnosis usually occurs in secondary care with data from our trust revealing long wait times to undertake tests, reach a diagnosis and start treatment. This places a considerable time and emotional burden on the patient and a financial and logistical burden on the hospital. METHODS: We introduced an integrated community-based pathway for the diagnosis of OSA. This comprised a monthly clinic run from within a local general practice (GP) supported by a 'virtual multidisciplinary team' run by the hospital specialist team. Prospective collection of process, outcome and patient satisfaction data was compared with traditional hospital-based pathway data collected retrospectively. SETTING: A central London teaching hospital and GPs within a local commissioning neighbourhood. RESULTS: Between January 2018 and February 2019, 70 were patients referred and managed along the community pathway. Compared with the hospital pathway, data demonstrated a significant reduction in the time taken: from referral to perform a sleep test (29 vs 181 days, p<0.0001), to make a diagnosis (40 vs 230 days, p<0.0001) and commence treatment (127 vs 267, p<0.0001). Patient satisfaction in the community pathway was higher across all domains (p<0.05), fewer hospital outpatient appointments were required and cost estimates suggested an overall saving of up to £290 could be achieved for each patient. CONCLUSION: An integrated community-based pathway results in more timely diagnosis of OSA within a local setting while maintaining specialist input from the hospital team. It is favoured by patients and can reduce unnecessary appointments in secondary care

First hours of the GRB 030329 optical afterglow

We present the first results of the observations of the extremely bright optical afterglow of gamma-ray burst (GRB) 030329 with the 1.5m Russian-Turkish telescope RTT150 (TUBITAK National Observatory, Bakyrlytepe, Turkey). RTT150 was one of the first 1.5m-class telescopes pointed to the afterglow. Observations were started approximately 6 hours after the burst. During the first 5 hours of our observations the afterglow faded exactly as a power law with index -1.19+-0.01 in each of the BVRI Bessel filters. After that, in all BVRI filters simultaneously we observe a steepening of the power law light curve. The power law decay index smoothly approaches the value ~= -1.9, observed by other observatories later. This power law break occurs at t-t_0 =0.57 days and lasts for +-0.1 days. We observe no variability above the gradual fading with the upper limits 10--1% on time scales 0.1--1000s. Spectral flux distribution in four BVRI filters corresponds to the power law spectrum with spectral index \alpha=0.66+-0.01. The change of the power law decay index in the end of our observations can be interpreted as a signature of collimated ultrarelativistic jet. The afterglow flux distribution in radio, optical and x-rays is consistent with synchrotron spectrum. We continue our observations of this unique object with RTT150.Comment: Astronomy Letters, Vol. 29, No. 9, p. 573; 6 pages, 5 figures; pagination corrected; the original Russian version can be found at http://hea.iki.rssi.ru/~br/030329/pfh030329.pd

Nanomechanical characterization by double-pass force-distance mapping

Cataloged from PDF version of article.We demonstrate high speed force–distance mapping using a double-pass scheme. The topography is measured in tapping mode in the first pass and this information is used in the second pass to move the tip over the sample. In the second pass, the cantilever dither signal is turned off and the sample is vibrated. Rapid (few kHz frequency) force–distance curves can be recorded with small peak interaction force, and can be processed into an image. Such a double-pass measurement eliminates the need for feedback during force–distance measurements. The method is demonstrated on self-assembled peptidic nanofibers

Effect of Fat and Casein Particles in Milk on the Scattering of Elliptically Polarized Light

In this article, we present an experimental approach to determine the milk fat content using scattered light intensity profiles. The elements of the scattering (Mueller) matrix have been shown to provide valuable information about variation of the optical properties of scattering particles. The scattering behavior of fat and casein in terms of the scattering matrix elements was experimentally determined for milk with varying fat levels ranging from 0.05 wt% (skim) to 3.20 wt% (whole). Three of the scattering Mueller matrix elements, specifically S11, S12/S11, and S33/S11, were found to be sensitive to the number of fat particles in milk. These results indicate that it should be possible to develop a reliable sensor based on the measurement of these scattering elements, which will allow for the development of a robust, in-line sensor to be used in food processing. In addition, an attempt was made to model the phenomena using a relatively simple approach based on single scattering with a size distribution. The disagreement between the model and experiments suggests that a more comprehensive model is needed which can account for multiple scattering