Detecting DDoS Attacks in Cloud Computing Using Extreme Learning Machine and Adaptive Differential Evolution

Wireless Personal Communications - Distributed denial of service (DDoS) attacks disrupt the availability of cloud services. The detection of these attacks is a major challenge in the cloud...     

Changes in liver lipids after administration of 2-decanoylamino-3-morpholinopropiophenone and chlorpromazine

The enzyme which forms glucocerebroside, ceramide: UDP-glucose glucosyltransferase, is inactivated in vitro by a cationic analog of cerebroside, 2-decanoylamino-3-morpholinopropiophenone. A study of the inhibitor using intraperitoneal injection into young mice showed that the level of the enzyme activity in liver was appreciably lowered between 3 and 6 hr after injection. The activity increased subsequently, overshooting the normal level within 24 hr by about 20%, then returning to normal within the next 24 hr. Additional effects observed in liver were an increase in lipid content (primarily in the triglyceride fraction and ceramides) and a decrease in the glucocerebroside level. Body temperature dropped rapidly. Markedly similar effects were produced by injecting chlorpromazine, which was tried in order to reduce the hyperirritability and inhibitory effects on monoamine oxidase previously demonstrated by the glucosyltransferase inhibitor. Chlorpromazine did indeed block the hyperirritability and resulted in enhancement of the keto amine's effects on the enzyme and lipids. It is possible that the two drugs in combination would be helpful in ameliorating the symptoms due to the cerebroside accumulation that occurs in Gaucher disease. Diazepam also produced a reduced level of glucosyltransferase. A color reaction for chlorpromazine, possibly suitable for quantitative determination in tissues, was accidentally discovered.     

Low-pressure synthesis of polycrystalline diamond abrasive

Polycrystalline diamond abrasives are used extensively for grinding of cemented tungsten carbide. Although these diamond crystals are somewhat weaker than the well formed cubo-octahedral crystals, they are ideal for grinding cemented carbide without causing surface integrity problems (metallurgical damage and microcraking due to thermal and mechanical stresses). Polycrystalline diamond of this type is currently produced by the high-pressure—high-temperature (HP-HT) technique. In this paper, we report an alternative technique for the production of polycrystalline diamond abrasive, namely combustion synthesis, using a simple oxy-acetylene torch. Although the growth rates by this technique are currently two orders of magnitude lower than the HP-HT technique, in view of the simplicity of this technique, the low cost of equipment as well as the lower running and maintenance costs (compared to the HP-HT presses, dies, power, etc.) activated chemical vapor deposition (CVD) diamond synthesis has potential for becoming an alternative approach to the growth of diamond crystals for abrasive applications. The situation will be more favorable with further advances in the low-pressure, activated CVD processes, which are still in their initial stages of development (similar to the HP-HT situation in the late 1950s), while the HP-HT process is more or less a matured technology.     

Thermal analysis of laser surface transformation hardening—optimization of process parameters

This paper deals with the optimization of process parameters for maximum productivity (given by the product of scanning velocity and cross feed) in laser transformation hardening. The process parameters considered are laser beam power, P; laser beam diameter, D_b; and the heat intensity distribution, namely, normal, bimodal, or uniform. A thermal analysis of the laser surface transformation hardening of gears was conducted (based on Jaeger’s classical moving heat source method) by considering the laser beam as a moving plane (disc) heat source to establish the temperature rise distribution in the workpiece (gear) of finite width. In a recent investigation [Int. J. Heat Mass Transfer 44 (2001) 2845], the authors considered the case of a heat source with a pseudo-Gaussian (or normal) distribution of heat intensity. The analytical results were compared with the experimental results published in the literature. In laser heat treatment of steel, it is generally considered preferable to use a wider heat intensity distribution, such as uniform or bimodal, for it enables more uniform case hardening depth. In this paper, this model is extended to cover bimodal and uniform distributions and compared with the normal distribution. Scanning velocities for no surface melting and for a case hardening depth of 0.1 mm were determined for surface transformation hardening of AISI 1036 (EN 8) steel for a range of laser beam powers, P, laser beam diameters, D_b, and various heat intensity distributions. Since diffusion during the heat treatment (surface transformation hardening) process is a time dependent phenomenon, based on the literature review, an interaction time of 15 ms was taken as a basis. It is hoped that laser industry with adequate facilities available can validate the thermal analysis and subsequent optimization presented in this paper.     

Generating vegetation leaf area index Earth system data record from multiple sensors. Part 2: Implementation,analysis and validation

The evaluation of a new global monthly leaf area index (LAI) data set for the period July 1981 to December 2006 derived from AVHRR Normalized Difference Vegetation Index (NDVI) data is described. The physically based algorithm is detailed in the first of the two part series. Here, the implementation, production and evaluation of the data set are described. The data set is evaluated both by direct comparisons to ground data and indirectly through inter-comparisons with similar data sets. This indirect validation showed satisfactory agreement with existing LAI products, importantly MODIS, at a range of spatial scales, and significant correlations with key climate variables in areas where temperature and precipitation limit plant growth. The data set successfully reproduced well-documented spatio-temporal trends and inter-annual variations in vegetation activity in the northern latitudes and semi-arid tropics. Comparison with plot scale field measurements over homogeneous vegetation patches indicated a 7% underestimation when all major vegetation types are taken into account. The error in mean values obtained from distributions of AVHRR LAI and high-resolution field LAI maps for different biomes is within 0.5 LAI for six out of the ten selected sites. These validation exercises though limited by the amount of field data, and thus less than comprehensive, indicated satisfactory agreement between the LAI product and field measurements. Overall, the inter-comparison with short-term LAI data sets, evaluation of long term trends with known variations in climate variables, and validation with field measurements together build confidence in the utility of this new 26 year LAI record for long term vegetation monitoring and modeling studies.     

Near-optimal gait generations of a two-legged robot on rough terrains using soft computing

A two-legged robot will have to generate its near-optimal gaits after ensuring maximum dynamic balance margin and minimum power consumption, while moving on the rough terrains containing some staircases and sloping surfaces. Moreover, the changes of joint torques should lie below a pre-specified small value to ensure its smooth walking. The balance of the robot and its power consumption are also dependent on hip trajectory and position of the masses on various limbs. Both neural network- and fuzzy logic-based gait planners have been developed for the same, the training of which are provided using a genetic algorithm off-line. Once optimized, the planners are found to generate optimal gaits of the two-legged robot successfully for the test cases.     

Theorem Proving Guided Development of Formal Assertions in a Resource-Constrained Scheduler for High-Level Synthesis

This paper presents a formal specification and a proof of correctness for the widely-used Force-Directed List Scheduling (FDLS) algorithm for resource-constrained scheduling of data flow graphs in high-level synthesis systems. The proof effort is conducted using a higher-order logic theorem prover. During the proof effort many interesting properties of the FDLS algorithm are discovered. These properties are formally stated and proved in a higher-order logic theorem proving environment. These properties constitute a detailed set of formal assertions and invariants that should hold at various steps in the FDLS algorithm. They are then inserted as programming assertions in the implementation of the FDLS algorithm in a production-strength high-level synthesis system. When turned on, the programming assertions (1) certify whether a specific run of the FDLS algorithm produced correct schedules and, (2) in the event of failure, help discover and isolate programming errors in the FDLS implementation.We present a detailed example and several experiments to demonstrate the effectiveness of these assertions in discovering and isolating errors. Based on this experience, we discuss the role of the formal theorem proving exercise in developing a useful set of assertions for embedding in the scheduler code and argue that in the absence of such a formal proof checking effort, discovering such a useful set of assertions would have been an arduous if not impossible task.     

Flow structure and scour around circular compound bridge piers – A review

Large amount of literature is presently available on the topic of scour around uniform piers and its control. However, relatively fewer studies have been carried out so far on the topic of flow field and scour around compound piers. The state of art on the topic of flow structure and scour around circular compound piers is presented herein. The available literature reveals that variations in foundation and pier geometry significantly affect the maximum depth of scour and its temporal variation. In case of compound piers the scour depth is highly sensitive to the change in elevation of the top surface of the foundation well. As compared to uniform piers, a reduction is observed in maximum depth of scour around compound pier when the top surface of the well is kept below the general level of river bed. These observations however are yet to be quantified. Results from an experimental study on flow field around the compound piers are also presented.