An analysis of the Slapper worm

We can prove that the Slapper is a variation of the Apache Scalper worm by comparing the source code. Modifications introduced in the Slapper worm improved the robustness and efficiency of its predecessor's simplistic P2P networking capabilities. Slapper's author also removed certain features from the original-either because they were redundant or to reduce the perception that it was a tool developed to cause direct harm to networks. Among the features the author removed from the Slapper were capabilities to update itself from a remotely specified Web server (perhaps to prevent someone else from replacing this version with a new one), to attack and infect a host specified with a controlling program, and to send spans. Interestingly, the ability to execute distributed denial-of-service attacks on a controlling user's behalf was kept intact. Slapper's author attempted to make communications with a remote controlling program as stealthy and untraceable as possible by removing several commands to query status and obtain feedback from Slapper nodes.     

Effect of spontaneous polarization on the energy levels in quantum wells formed at the contact between cubic and noncubic silicon carbide polytypes

We have studied the effect of spontaneous polarization, which is inherent in noncubic silicon carbide (SiC) polytypes, on the characteristics of quantum wells (QWs) formed in the cubic region at the heterojunction. The analysis is performed for various QW models, including triangular, parabolic, and exponential. Conditions for the appearance of a two-dimensional electron gas at the interface are briefly discussed.     

Microhardness of silicon layers grown by liquid phase epitaxy

The microhardness of silicon epilayers grown from Sn fluxes is found to be lower than that of the silicon substrates and to significantly depend on the crystallographic orientation of the substrates. The microhardness values follow a Gaussian distribution in all of the epilayers. Unintentional impurities are shown to have a significant effect on the microhardness of the epilayers. The addition of ytterbium to the high-temperature solution reduces the microhardness of the epilayers.     

Direct transformation of nonlinear systems into state affine MISO form for observer design

This paper gives necessary and sufficient conditions to solve in a constructive way the transformation of a general multiple-input-single-output nonlinear system into a state affine system. This result is direct i.e., without solving the state elimination problem when computing the input-output differential equation. A Kalman-like observer can be designed for the obtained state affine system.     

The behavior of a cloud of emissions of high moisture content in the surface layer of the atmosphere

The propagation in the atmosphere of instantaneous emissions which largely consist of water vapor is treated in a three-dimensional formulation. The regularities are studied of the evolution of the hydrodynamic, concentration, and temperature fields depending on the parameters which define the state of the atmosphere (temperature and humidity), as well as on the temperature and moisture content of the cloud of emissions.     

The fractal structure of a carbon deposit formed during graphite spraying in an electric arc

Experimental data obtained by atomic force microscopy showing that a carbon deposit formed during graphite spraying in an electric arc possesses a fractal structure. The deposit is composed of clusters with dimensions on the order of 1–5 nm. The surface and profile of the deposit exhibit a self-affine fractal structure. The fractal dimensions of the deposit surface and profile, as well as the Hurst index characterizing the self-affine fractal, are determined.     

Survey of nitrate and nitrite contents of vegetables grown in Korea.

A scientific basis for the evaluation of the risk to public health arising from excessive dietary intake of nitrate in Korea is provided. The nitrate () and nitrite () contents of various vegetables (Chinese cabbage, radish, lettuce, spinach, soybean sprouts, onion, pumpkin, green onion, cucumber, potato, carrot, garlic, green pepper, cabbage and Allium tuberosum Roth known as Crown daisy) are reported. Six hundred samples of 15 vegetables cultivated during different seasons were analysed for nitrate and nitrite by ion chromatography and ultraviolet spectrophotometry, respectively. No significant variance in nitrate levels was found for most vegetables cultivated during the summer and winter harvests. The mean nitrates level was higher in A. tuberosum Roth (5150 mg kg(-1)) and spinach (4259 mg kg(-1)), intermediate in radish (1878 mg kg(-1)) and Chinese cabbage (1740 mg kg(-1)), and lower in onion (23 mg kg(-1)), soybean sprouts (56 mg kg(-1)) and green pepper (76 mg kg(-1)) compared with those in other vegetables. The average nitrite contents in various vegetables were about 0.6 mg kg(-1), and the values were not significantly different among most vegetables. It was observed that nitrate contents in vegetables varied depending on the type of vegetables and were similar to those in vegetables grown in other countries. From the results of our studies and other information from foreign sources, it can be concluded that it is not necessary to establish limits of nitrates contents of vegetables cultivated in Korea due to the co-presence of beneficial elements such as ascorbic acid and alpha-tocopherol which are known to inhibit the formation of nitrosamine.     

Navigation of a Mobile System with Parametrically Uncertain State Vector

Navigation of a mobile system with parametrically uncertain state vector is studied. The required navigation accuracy is attained through orientation control of the gyrostabilized platform and identification of the parameters of the model of the platform drift. A wide range of functionals that depend on the a posteriori distribution density can be used as the optimization criteria since the solution is general. In the numerical example, the Shannon criterion is used as the optimization criterion.