4,195 research outputs found

    Hypervisor Integrity Measurement Assistant

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    An attacker who has gained access to a computer may want to upload or modify configuration files, etc., and run arbitrary programs of his choice. We can severely restrict the power of the attacker by having a white-list of approved file checksums and preventing the kernel from loading loading any file with a bad checksum. The check may be placed in the kernel, but that requires a kernel that is prepared for it. The check may also be placed in a hypervisor which intercepts and prevents the kernel from loading a bad file. We describe the implementation of and give performance results for two systems. In one the checksumming, or integrity measurement, and decision is performed by the hypervisor instead of the OS. In the other only the final integrity decision is done in the hypervisor. By moving the integrity check out from the VM kernel it becomes harder for the intruder to bypass the check. We conclude that it is technically possible to put file integrity control into the hypervisor, both for kernels without and with pre-compiled support for integrity measurement

    Elemental Analysis of the JSC Mars-1 Soil Simulant using Laser Ablation and Magnetic Separation

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    Future long-duration missions to Mars require capabilities in terms of manufacture of structures and chemical compounds essential for human habitat and exploratory activities. Currently, it is not feasible to import all the required raw and finished materials from Earth. In fact, essential items such as structural members as well as various gases for human consumption and material processing need to be largely extracted from the available planetary resources. The resources on Mars include its soil and rocks, its atmosphere and the polar caps. Mars atmosphere consists of 95% carbon dioxide and the balance contains small percentages of oxygen, nitrogen, and argon. The Mars regolith contains many metal oxides in various mineralogical forms. Presently, Martian soil samples are not available. However, a closely matched Martian soil simulant developed by the Johnson Space Center has been available for scientific research and engineering studies. The chemical makeup of this simulant is compared with the data from Viking Lander and Path Finder missions are shown.

    Chemical and sensory properties of fish sauce using dried rainbow sardine (Dussumieria acuta)

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    Fish sauce is a dark liquid which produced from fish fermentation in a very high salt condition. This product has a long history and is produced in different procedures and names throughout the world. In Iran, production of fish sauce consists of two steps. At first, fermented extract or Suru is produced from fresh or dried sardine, and Suru is cured with the addition of spices. This study was conducted for the first time in Iran for industrial production of fish sauce from dried Sardine. For this study, fresh sardine was provided from Bandar Abbas Fishery Center. The fish were sun-dried and used for fish sauce production. The effects of mechanical dicing, adding of salt in two levels (100 and 80 percent) and addition of citric acid at 2% were investigated. Sampling was achieved with separation of aqueous phase by vacuum and filter paper. Then, acidity, electrical conductivity, total nitrogen, trimethylamine and salt concentration were measured in the extracted liquid. Results showed that acidity, electrical conductivity and total nitrogen increased, however, the salt content remained constant and the trimethylamine content was decreased during fermentation period. Increase in total nitrogen indicated an increase in protein hydrolysis and nutritional value of the product. Whereas, reduction in trimethylamine content showed a decrease in the number of spoilage bacteria during fermentation. The highest score in sensory evaluation of the products belonged to the low salt (80%) treatment
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