China
Africa
Explore chapters and articles related to this topic
War of Control Hijacking
Published in Uzzal Sharma, Parmanand Astya, Anupam Baliyan, Salah-ddine Krit, Vishal Jain, Mohammad Zubair Khan, Advancing Computational Intelligence Techniques for Security Systems Design, 2023
Ragini Karwayun, Monika Sainger
The idea is to categorize the memory range into either writable or executable (but not both); this prevents the execution of code injected as data into the system. It prevents code execution by marking stack and heap as non-executable. To be precise, memory regions identified as “data-only” are never treated as instructions, thus making code injection ineffective. This security policy is enforced in hardware using NX-bit on AMD Athlon 64 or XD-bit on Intel P4 Prescott. AMD names this protection feature as Enhanced Virus Protection. The NX-bit, which is used to represent Never eXecute, is a tool used to separately differentiate between areas of memory reserved for storage of data or for storage of processor instructions (or code). An operating system may identify specific areas of memory as non-executable. Any code belonging to this marked memory area will not be executed by the processor. NX-bit is used in every page table entry and is set to “1” if we wish to make the data residing on this page un-executable.
Optimization of Ventilation Ports of Packaging for Fresh Produce Using CFD
Published in Da-Wen Sun, Computational Fluid Dynamics in Food Processing, 2018
The Reynolds number at the inlet port determined using Equation 7.1 is maximum, i.e., approximately 2150, when U is 1.5 m−1 and d is 21 mm. The airflow through the inlet port is expected to form a turbulent field in a very limited region. However, a laminar flow, which is simpler for analysis, was assumed because the main objective was to investigate the overall ventilation state in the box. In the simulation, a steady state calculation was performed, and when the residual of the numerical calculation concerning the air velocity was less than 10−3, the calculation was assumed to be converged. For calculation, a personal computer (OPTIPLEX 740, Dell Japan, Kawasaki, Japan, CPU: AMD Athlon 64 X2 4000+ Dual core processor, RAM: 1.93 GB) was connected to the Calculation System for Science and Technology of Agriculture, Forestry and Fisheries Research Information Technology Center of MAFF, Japan.
Speeding Up Monte Carlo Computations by Parallel Processing Using a GPU for Uncertainty Evaluation in accordance with GUM Supplement 2
Published in NCSLI Measure, 2018
C. M. Tsui, Aaron Y. K. Yan, H. W. Lai
There are several public-domain tools for testing the quality of pseudo-random number generators (PRNG). Some examples are the DIEHARD, the NIST test suite and TestU01 [5]. TestU01 is a library of C programs containing many statistical tests, such as global uniformity test, clustering test, and run and gap tests, to name a few, for gauging the performances of PRNGs. TestU01 also provides predefined tests suites (called batteries) that may be invoked by a single function call. The SmallCrush, Crush and BigCrush batteries are commonly used suites. The SmallCrush battery contains the smallest number of tests and may be completed in less than one minute. The Crush battery contains more tests and takes around one hour to complete. The BigCrush battery is the most stringent test suite and takes several hours to run on a 2.4 GHz AMD Athlon 64 CPU. A PRNG that passes the BigCrush battery is generally considered good enough for MCM applications.
Rolling horizon production scheduling of multi-model PCBs for several assembly lines
Published in International Journal of Production Research, 2020
Jani Koskinen, Csaba Raduly-Baka, Mika Johnsson, Olli S. Nevalainen
All runs were performed on a PC with an Athlon 64-processor (X2 4200+ GHz) using windows XP. The algorithms were coded in Java. The running time for Data 1 was then ca. 3 sec (10 jobs, 3 lines) and for Data 2 somewhat more than 2 min (100 jobs, 5 lines).