Development of dynamic protection against timing channels

Information systems face many threats, such as covert channels, which declassify hidden information by, e.g., analyzing the program execution time. Such threats exist at various stages of the execution of instructions. Even if software developers are able to neutralize these threats in source code, new attack vectors can arise in compiler-generated machine code from these representations. Existing approaches for preventing vulnerabilities have numerous restrictions related to both their functionality and the range of threats that can be found and removed. This study presents a technique for removing threats and generating safer code using dynamic compilation in an execution environment by combining information from program analysis of the malicious code and re-compiling such code to run securely. The proposed approach stores summary information in the form of rules that can be shared among analyses. The annotations enable us to conduct the analyses to mitigate threats. Developers can update the analyses and control the volume of resources that are allocated to perform these analyses by changing the precision. The authors’ experiments show that the binary code created by applying the suggested method is of high quality.     

Biogeography-based optimisation with chaos

The biogeography-based optimisation (BBO) algorithm is a novel evolutionary algorithm inspired by biogeography. Similarly, to other evolutionary algorithms, entrapment in local optima and slow convergence speed are two probable problems it encounters in solving challenging real problems. Due to the novelty of this algorithm, however, there is little in the literature regarding alleviating these two problems. Chaotic maps are one of the best methods to improve the performance of evolutionary algorithms in terms of both local optima avoidance and convergence speed. In this study, we utilise ten chaotic maps to enhance the performance of the BBO algorithm. The chaotic maps are employed to define selection, emigration, and mutation probabilities. The proposed chaotic BBO algorithms are benchmarked on ten test functions. The results demonstrate that the chaotic maps (especially Gauss/mouse map) are able to significantly boost the performance of BBO. In addition, the results show that the combination of chaotic selection and emigration operators results in the highest performance.     

The color of dragline silk produced in captivity by the spider Nephila clavipes

Fifty-six N. clavipes spiders from the same region of Florida were kept in captivity under the same conditions and fed a similar diet of crickets. Their major ampulate glands were forcibly silked. Dates, silking times, and the colors of the dragline silk produced were recorded. The colors ranged from all white through various combinations of white and yellow upon different silkings to all yellow. If a spider had been producing white silk for at least 4 h, the color being produced could suddenly change to yellow 38% of the time. These observations indicate that factors beyond diet and environment influence the color of silk produced in captivity by forcible silking. They also indicate that the spiders store both pigmented and unpigmented silks and that some aspect of forcible silking precludes the spiders' choosing the color. The yellow and white silks exhibit similar exterior surface morphologies as well as similar tensile properties.     

Policing as a Service in the Cloud

ABSTRACT

Security and privacy are fundamental concerns in cloud computing both in terms of legal complications and user trust. Cloud computing is a new computing paradigm, aiming to provide reliable, customized, and guaranteed computing dynamic environment for end users. However, the existing security and privacy issues in the cloud still present a strong barrier for users to adopt cloud computing solutions. This paper investigates the security and privacy challenges in cloud computing in order to explore methods that improve the users’ trust in the adaptation of the cloud. Policing as a Service can be offered by the cloud providers with the intention of empowering users to monitor and guard their assets in the cloud. This service is beneficial both to the cloud providers and the users. However, at first, the cloud providers may only be able to offer basic auditing services due to undeveloped tools and applications. Similar to other services delivered in the cloud, users can purchase this service to gain some control over their data. The subservices of the proposed service can be Privacy as a Service and Forensics as a Service. These services give users a sense of transparency and control over their data in the cloud while better security and privacy safeguards are sought.     

Statistical analysis of nanofibers alignment in magnetic‐field‐assisted electrospinning including an alignment percentage formula

Magnetic‐field‐assisted electrospinning (MFAES) is a simple and effective method to align polymer nanofibers. In this method, further research is needed to identify alignment mechanism. Hence, this article includes statistical analysis of affecting factors to investigate alignment mechanism in MFAES. Tip to target distance, magnets distance, voltage, and collection time, which are recognized as the most effective factors on nanofibers alignment, were applied in design of experiments. Central composite method was applied to get required experiments with designed expert 8 software. A response surface was proposed with regression coefficient of 97%. Then, the common physics concepts and statistical results were used to discuss the affecting mechanism of the electric and magnetic fields on the electrospinnig jet and the nanofibers alignment. Field emission scanning electron microscopy images were used to characterize the nanofibers alignment and calculate overall alignment percentage using a proposed statistical combinatorial weighted percentage formula. MFAES method, used in this research, achieved 95.3% polyacrylonitrile‐aligned nanofibers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41179.     

On the least restrictive control for collision avoidance of two unicycles

We give an explicit analytical characterization of the least restrictive control for collision avoidance of two unicycles. The controller is proved to be least restrictive using viability theory. Copyright © 2006 John Wiley & Sons, Ltd.     

The frequency and predictors of helmet use among Iranian motorcyclists: A quantitative and qualitative study

Objective

This study examines the rate of helmet use and identifies barriers and facilitators of wearing helmets among Iranian motorcyclists. A mixed-method approach was used, including a structured seasonal survey with specific observations of a random sample of 6010 riders and qualitative methods that included 29 in-depth interviews and seven focus groups (n = 31).

Results

Only 10% of motorcyclists wear a standard helmet while riding. However, another 23% of motorcyclists used non-standard or partial helmets that covered only part of the head and do not prevent head trauma injuries effectively. We observed only 2 of 264 child passengers and 22 of 1951 adult passengers wearing helmets. Almost no one used protective pants or clothing made to be more visible in traffic. Themes emerged from qualitative interviews and were grouped into three main categories: (1) helmet characteristics; (2) social and cultural factors; and (3) personal and psychological factors.

Conclusion

Overall, the motorcyclists in our study believed that wearing a safety helmet protects them against serious injuries or death during a crash; however, only a small percentage of the motorcyclists used safety helmets. National intervention programs addressing motorcycle safety should aim to overcome barriers to and promote facilitators of helmet use, including providing inexpensive standard helmets, banning manufacturing/using unsafe partial or dummy helmets, as well as enforcing helmet use on a consistent basis.