A model checking-based approach for security policy verification of mobile systems

This article describes an approach for the automated verification of mobile systems. Mobile systems are characterized by the explicit notion of location (e.g., sites where they run) and the ability to execute at different locations, yielding a number of security issues. To this aim, we formalize mobile systems as Labeled Kripke Structures, encapsulating the notion of location net that describes the hierarchical nesting of the threads constituting the system. Then, we formalize a generic security-policy specification language that includes rules for expressing and manipulating the code location. In contrast to many other approaches, our technique supports both access control and information flow specification. We developed a prototype framework for model checking of mobile systems. It works directly on the program code (in contrast to most traditional process-algebraic approaches that can model only limited details of mobile systems) and uses abstraction-refinement techniques, based also on location abstractions, to manage the program state space. We experimented with a number of mobile code benchmarks by verifying various security policies. The experimental results demonstrate the validity of the proposed mobile system modeling and policy specification formalisms and highlight the advantages of the model checking-based approach, which combines the validation of security properties with other checks, such as the validation of buffer overflows.     

The Dynamics of Syntactic Knowledge

The syntactic approach to epistemic logic avoids the logicalomniscience problem by taking knowledge as primary rather thanas defined in terms of possible worlds. In this study, we combinethe syntactic approach with modal logic, using transition systemsto model reasoning. We use two syntactic epistemic modalities:‘knowing at least’ a set of formulae and ‘knowingat most’ a set of formulae. We are particularly interestedin models restricting the set of formulae known by an agentat a point in time to be finite. The resulting systems are investigatedfrom the point of view of axiomatization and complexity. Weshow how these logics can be used to formalise non-omniscientagents who know some inference rules, and study their relationshipto other systems of syntactic epistemic logics, such as Ågotnesand Walicki (2004, Proc. 2nd EUMAS, pp. 1–10), Alechinaet al. (2004, Proc. 3rd AAMAS, pp. 601–613), Duc (1997,J. Logic Comput., 7, 633–648).     

Die Rolle der Kultur in der Selbstoffenbarung und Privatsph?re in sozialen Onlinenetzwerken

Social Network Sites (SNSs) rely exclusively on user-generated content to offer engaging and rewarding experience to its members. As a result, stimulating user communication and self-disclosure is vital for the sustainability of SNSs. However, considering that the SNS users are increasingly culturally diverse, motivating this audience to self-disclose requires understanding of their cultural intricacies. Yet existing research offers only limited insights into the role of culture behind the motivation of SNS users to self-disclose. Building on the privacy calculus framework, this study explores the role of two cultural dimensions ?C individualism and uncertainty avoidance ?C in self-disclosure decisions of SNS users. Survey responses of US and German Facebook members are used as the basis for our analysis. Structural equation modeling and multi-group analysis results reveal the distinct role of culture in the cognitive patterns of SNS users. The authors find that trusting beliefs play a key role in the self-disclosure decisions of users from individualistic cultures. At the same time, uncertainty avoidance determines the impact of privacy concerns. This paper contributes to the theory by rejecting the universal nature of privacy calculus processes. The findings provide for an array of managerial implications for SNS providers as they strive to encourage content creation and sharing by their heterogeneous members.     

The Promise of Novel Molecular Markers in Bladder Cancer

Bladder cancer is the fourth most common malignancy in the US and is associated with the highest cost per patient. A high likelihood of recurrence, mandating stringent surveillance protocols, has made the development of urinary markers a focus of intense pursuit with the hope of decreasing the burden this disease places on patients and the healthcare system. To date, routine use of markers is not recommended for screening or diagnosis. Interests include the development of a single urinary marker that can be used in place of or as an adjunct to current screening and surveillance techniques, as well identifying a molecular signature for an individual’s disease that can help predict progression, prognosis, and potential therapeutic response. Markers have shown potential value in improving diagnostic accuracy when used as an adjunct to current modalities, risk-stratification of patients that could aid the clinician in determining aggressiveness of surveillance, and allowing for a decrease in invasive surveillance procedures. This review discusses the current understanding of emerging biomarkers, including miRNAs, gene signatures and detection of circulating tumor cells in the blood, and their potential clinical value in bladder cancer diagnosis, as prognostic indicators, and surveillance tools, as well as limitations to their incorporation into medical practice.     

Effect of pasture versus indoor feeding systems on quality characteristics,nutritional composition,and sensory and volatile properties of full-fat Cheddar cheese

The purpose of this study was to investigate the effects of pasture-based versus indoor total mixed ration (TMR) feeding systems on the chemical composition, quality characteristics, and sensory properties of full-fat Cheddar cheeses. Fifty-four multiparous and primiparous Friesian cows were divided into 3 groups (n = 18) for an entire lactation. Group 1 was housed indoors and fed a TMR diet of grass silage, maize silage, and concentrates; group 2 was maintained outdoors on perennial ryegrass only pasture (GRS); and group 3 was maintained outdoors on perennial ryegrass/white clover pasture (CLV). Full-fat Cheddar cheeses were manufactured in triplicate at pilot scale from each feeding system in September 2015 and were examined over a 270-d ripening period at 8°C. Pasture-derived feeding systems were shown to produce Cheddar cheeses yellower in color than that of TMR, which was positively correlated with increased cheese β-carotene content. Feeding system had a significant effect on the fatty acid composition of the cheeses. The nutritional composition of Cheddar cheese was improved through pasture-based feeding systems, with significantly lower thrombogenicity index scores and a greater than 2-fold increase in the concentration of vaccenic acid and the bioactive conjugated linoleic acid C18:2 cis-9,trans-11, whereas TMR-derived cheeses had significantly higher palmitic acid content. Fatty acid profiling of cheeses coupled with multivariate analysis showed clear separation of Cheddar cheeses derived from pasture-based diets (GRS or CLV) from that of a TMR system. Such alterations in the fatty acid profile resulted in pasture-derived cheeses having reduced hardness scores at room temperature. Feeding system and ripening time had a significant effect on the volatile profile of the Cheddar cheeses. Pasture-derived Cheddar cheeses had significantly higher concentrations of the hydrocarbon toluene, whereas TMR-derived cheese had significantly higher concentration of 2,3-butanediol. Ripening period resulted in significant alterations to cheese volatile profiles, with increases in acid-, alcohol-, aldehyde-, ester-, and terpene-based volatile compounds. This study has demonstrated the benefits of pasture-derived feeding systems for production of Cheddar cheeses with enhanced nutritional and rheological quality compared with a TMR feeding system.     

Rational Optimization of Dihydropyrimidinone-Quinoline Hybrids as Plasmodium falciparum Glutathione Reductase Inhibitors

A series of dihydropyrimidinone-based antimalarial compounds were designed and synthesised based on the previously identified amide-based quinoline hybrids which showed good resistance reversal ability against the resistant strain of Plasmodium falciparum. The aromatic ring on the dihydropyrimidinone of the original hits was exchanged for a methyl group to bring the molecular weights below 500 Da and also determine the effect of the aromatic ring count on the resistance reversal ability of the hybrids. Apart from the previously used amide bond, the hybrid linker was also extended to the triazole linker. Although the triazole linker is synthetically easier to access, the use of an amide linker seems to have an activity advantage. The synthesised compounds in addition to the previously identified hits were subjected to molecular docking particularly targeting the orthosteric site of Plasmodium falciparum glutathione reductase (PfGR) protein. The ligand with the best binding interaction was rationally optimised to increase its suitability as a competitive inhibitor against the cofactor of the PfGR. Two of the optimised ligands showed better binding affinities than the cofactor while one of the two ligands displayed hydrophobically packed correlated hydrogen-bond which is very important in maintaining the ligand stability within the protein. In silico ADME predictions of the synthesised compounds indicate that these compounds possess good pharmacokinetic properties.     

Agricultural proteins as multifunctional additives in ZnO-free synthetic isoprene rubber vulcanizates

Corn zein and wheat gliadin protein are compounded into synthetic cis-1,4-polyisoprene rubber (IR) and sulfur-cured in a zinc oxide (ZnO)-free system. The curing kinetics and mechanical and morphological properties are compared to a ZnO-activated or carbon black (CB)-reinforced cure system. The proteins provide reversion resistance and reinforcement to IR at filler loadings as low as 1 part per hundred rubber (phr). The zein-IR composites exhibit higher moduli, better filler–matrix adhesion, and less filler agglomeration/migration than gliadin-IR because zein is more chemically compatible with IR. The gliadin-IR composites have a lower percent set and hysteresis, indicating the formation of an elastic restoring gliadin network. Optimal properties are achieved at 2-phr gliadin and 4-phr zein. At gliadin loading >2 phr and zein loading >4 phr, the protein domain size increases and mechanical properties deteriorate. At equal filler loading, property improvements over CB-IR are observed for one or both proteins. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48141.     

Ultrastructural and immunohistochemical study of the effect of sodium alendronate in the progression of experimental periodontitis in rats

The aim of the present research was to investigate the ultrastructural aspects and the immunoexpression of receptor activator of NFκB ligand (RANKL) and osteoprotegerin (OPG) on experimental periodontal disease of alendronate (ALN)‐treated rats. Male Wistar rats received daily injections of 2.5 mg/kg body weight of ALN during 7 days previously and 7, 14, and 21 days after the insertion of a 4.0 silk suture into the gingival sulcus around the right upper second molar. Specimens were fixed in 0.1% glutaraldehyde + 4% formaldehyde under microwave irradiation, decalcified in 4.13% EDTA and paraffin embedded for TRAP histochemistry and immunohistochemistry for RANKL and OPG, or embedded in Spurr epoxy resin for TEM analysis. ALN reduced the activity of osteoclasts and significantly decreased the resorption of the alveolar crest. In the control group the alveolar crest appeared resorbed by TRAP‐positive osteoclasts, which presented ultrastructural features of activated cells. The immunoexpression of RANKL was not inhibited by the drug; however, the expression of OPG was increased in the treated animals. The alveolar crest of ALN‐treated specimens at 21 days showed signs of osteonecrosis, like empty osteocyte lacunae, the exposed bone regions and bacterial infection. The results showed that ALN treatment in individuals with periodontal disease represents a risk of osteonecrosis because of the reduced activity of osteoclasts resultant of the increased immunoexpression of OPG. Microsc. Res. Tech. 77:902–909, 2014. © 2014 Wiley Periodicals, Inc.     

The combustion behavior of epoxy-based multifunctional electrolytes

Multifunctional or structural electrolytes are characterized by ionic conductivity high enough to be used in the electrochemical devices and mechanical performance suitable for the structural applications. Preliminary insights are provided into the combustion behavior of structural bi-continuous electrolytes based on bisphenol A diglycidyl ether (DGEBA), synthesized using the techniques of reaction induced phase separation and emulsion templating. The effect of the composition of the structural electrolytes and external heat flux on the behavior of the formulations were studied using a cone calorimeter with gases formed during testing analyzed using FTIR. The composition of the formulations investigated was changed by varying the type and amount of the ion conductive part of the bi-continuous electrolyte. Two ionic liquids, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIM-TFSI) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF₄), as well as a deep eutectic solvent (DES) based on ethylene glycol and choline chloride, were used. The results obtained confirm that time to ignition, heat release rate (HRR), total mass loss, as well as the composition of the gases released during tests depend on the composition of the formulations. Addition of liquid electrolyte is found to reduce the time to ignition by up to 10% and the burning time by between 28% and 60% with the added benefit of reducing the HRR by at least 34%. Gaseous products such as CO₂, CO, H₂O, CH₄, C₂H₂, N₂O, NO, and HCN were detected for all formulations with the gases SO₂, NH₃, HCl, C₂H₄, and NH₃ found to be for certain formulations only.     

Concurrent software verification with states, events, and deadlocks

We present a framework for model checking concurrent software systems which incorporates both states and events. Contrary to other state/event approaches, our work also integrates two powerful verification techniques, counterexample-guided abstraction refinement and compositional reasoning. Our specification language is a state/event extension of linear temporal logic, and allows us to express many properties of software in a concise and intuitive manner. We show how standard automata-theoretic LTL model checking algorithms can be ported to our framework at no extra cost, enabling us to directly benefit from the large body of research on efficient LTL verification. We also present an algorithm to detect deadlocks in concurrent message-passing programs. Deadlock- freedom is not only an important and desirable property in its own right, but is also a prerequisite for the soundness of our model checking algorithm. Even though deadlock is inherently non-compositional and is not preserved by classical abstractions, our iterative algorithm employs both (non-standard) abstractions and compositional reasoning to alleviate the state-space explosion problem. The resulting framework differs in key respects from other instances of the counterexample-guided abstraction refinement paradigm found in the literature. We have implemented this work in the magic verification tool for concurrent C programs and performed tests on a broad set of benchmarks. Our experiments show that this new approach not only eases the writing of specifications, but also yields important gains both in space and in time during verification. In certain cases, we even encountered specifications that could not be verified using traditional pure event-based or state-based approaches, but became tractable within our state/event framework. We also recorded substantial reductions in time and memory consumption when performing deadlock-freedom checks with our new abstractions. Finally, we report two bugs (including a deadlock) in the source code of Micro-C/OS versions 2.0 and 2.7, which we discovered during our experiments. This research was sponsored by the National Science Foundation (NSF) under grants no. CCR-9803774 and CCR-0121547, the Office of Naval Research (ONR) and the Naval Research Laboratory (NRL) under contract no. N00014-01-1-0796, the Army Research Office (ARO) under contract no. DAAD19-01-1-0485, and was conducted as part of the Predictable Assembly from Certifiable Components (PACC) project at the Software Engineering Institute (SEI). This article combines and builds upon the papers (CCO⁺04) and (CCOS04). Received December 2004 Revised July 2005 Accepted July 2005 by Eerke A. Boiten, John Derrick, Graeme Smith and Ian Hayes