A novel intrusion detection system based on hierarchical clustering and support vector machines

This study proposed an SVM-based intrusion detection system, which combines a hierarchical clustering algorithm, a simple feature selection procedure, and the SVM technique. The hierarchical clustering algorithm provided the SVM with fewer, abstracted, and higher-qualified training instances that are derived from the KDD Cup 1999 training set. It was able to greatly shorten the training time, but also improve the performance of resultant SVM. The simple feature selection procedure was applied to eliminate unimportant features from the training set so the obtained SVM model could classify the network traffic data more accurately. The famous KDD Cup 1999 dataset was used to evaluate the proposed system. Compared with other intrusion detection systems that are based on the same dataset, this system showed better performance in the detection of DoS and Probe attacks, and the beset performance in overall accuracy.     

Improving supercritical water gasification of sludge by oil palm empty fruit bunch addition: Promotion of syngas production and heavy metal stabilization

The co-gasification of sewage sludge and palm oil empty fruit bunch (EFB) in supercritical water (SCW) was conducted at 400℃ with a pressure of over 25 MPa. This study aimed to investigate the influence of EFB addition on the syngas production and its composition. The heavy metal distribution and the leaching potential of the solid residue were also assessed. The results showed that syngas yield significantly increased with the addition of EFB into the feedstock. The cold gas efficiency (CGE) and carbon efficiency (CE) of co-gasification were higher than those of individual gasification. The actual syngas production from co-gasification of sludge and EFB was 45% higher than the theoretical total volume. The results indicated that the addition of EFB to sludge had the synergetic promotion effect on syngas production from sludge and EFB in supercritical water. This enhancement might be due to the dissolution of alkali metals from EFB and the adjustment of organic ratio. In addition, higher percentage of heavy metals were deposited and stabilized in the solid residue after SCWG. The leaching concentration of heavy metals from the solid residues was decreased to a level below the standard limit which enables it to be safely disposed of in landfill. In conclusion, the EFB addition has been proved to promote syngas production, as well as, stabilize the heavy metal in solid residues during co-SCWG.     

Screening for lipid depositor of Indonesian microalgae isolated from seashore and peat-land

The screening for finding the lipid producer of indigenous Indonesian tropical microalgae that obtained from peat-land at Riau, Sumatra and seashore at Lombok has carried out. Preliminary screening was done by selection on faster growing algae from 44 (forty-four) isolates. 10 (ten) isolates were chosen for further analysis. Out of 10 selected isolates shows that five isolates have indication rapid growth and high content of lipid, furthermore those chose isolates were observed comprehensively, namely LIPI11-2-Al005, LIPI11-2-Al010, LIPI11-2-Al015, LIPI11-2-Al018, and LIPI11-2-Al019. The microalgae are belong to the eukaryotic microalgae and its seem to be closed to Chlorophytes that has cell nuclear with an envelope, light green chloroplast, thick cell wall, round and elongated cell features. Cultivation of the microalgae in laboratory condition (1 L) has shown that lipid content was about 20–35% base in cell dry weight. The highest lipid content was found in the isolate LIPI11-2-Al018 of 30.74% per dry weight cell. LIPI11-2-A1018 therefore was test for scale up cultivation reach the culture volume of 5 L in the cylindrical photobioreactor, and expected to be source of triglycerides and lipids for biodiesel ingredient.     

Influences of post weld heat treatment on fatigue crack growth behavior of TIG welding of 6013 T4 aluminum alloy joint (Part 1. Fatigue crack growth across the weld metal)

The present study evaluates the influences of PWHT on FCG behavior and tensile properties of TIG butt welded Al 6013-T4 sheets. Crack propagation tests were carried out on compact tension (CT) specimens. The T82 heat treatment was varied in three artificial aging times (soaking) of 6, 18 and 24 hours. The results of T82 heat treatment with artificial aging variations were tested for their fatigue crack growth rates at the main metal zone, the heat-affected zone (HAZ), and the welded metal zone. It has been observed that the various agings in heat treatment T82 are sensitive to the mechanical properties (fatigue crack growth rate test, tensile test). The results show that PWHT-T82 for 18 hours aging is the highest fatigue resistance, while the aging 18 hours provided the highest tensile test result.     

Optically stimulated luminescence in Cu-doped sodium chloride single crystal for a high-quality X-ray imaging sensor

An intense optically stimulated luminescence (OSL) has been observed, for the first time, in X-irradiated copper-doped sodium chloride (NaCl:Cu) single crystals. The intensity of the OSL peak at 353 nm is proportional to the optical density of the F centres that are created by X-ray irradiation. This suggests that NaCl:Cu is useful as a material for a two-dimensional X-ray imaging sensor in computed radiography utilizing the OSL phenomenon. A possible reaction responsible for the 353 nm OSL peak is also proposed, based on the recombination of Cu²⁺ ions with electrons released from the F centres.     

Subendocardial myocardial ischemia as assessed with myocardial contrast echocardiography in patients with ischemic heart diseases

Myocardial contrast echocardiography was used to characterize changes in the regional and transmural myocardial blood flow distribution that were provoked by rapid atrial pacing stress in patients with coronary artery diseases. In patients with coronary organic stenosis, a decrease in the myocardial contrast-enhancement in the subendocardial half after rapid atrial pacing was associated with stress-induced chest pain and electrocardiographic ST-T changes. The decrease in the myocardial contrast-enhancement in the subendocardial half after rapid atrial pacing was not observed in patients without coronary stenosis or after coronary angioplasty. Thus, the finding was considered to reflect myocardial ischemia. Pacing-induced decreases in myocardial contrast-enhancement were observed in some patients with old myocardial infarction and significant resting coronary collaterals. In these patients, myocardial ischemia was considered to have developed at rapid pacing because collateral function was good enough to perfuse the infarct myocardium at rest, but was not good enough to prevent myocardial ischemia at stress. Thus, myocardial contrast echocardiography seems to be particularly useful in assessing myocardial ischemia at stress due to coronary stenosis in patients with angina pectoris and due to poor dynamic collateral function in patients with old myocardial infarction.     

Intense white photoluminescence in ZnO thin film formed by anodization

Intense white photoluminescence (PL) at room temperature has been observed in ZnO thin films formed by anodization at 26? C. The PL depends on the preparation conditions of the films. The PL is attributed to radiative recombination between localized electrons and holes in gap states which are formed by native defects in the films. We suggest that the anodized ZnO films might be useful for optoelectronic devices, since the low temperature anodization process used is inexpensive and fast.     

The stability of zinc oxide transparent electrodes fabricated by R.F. magnetron sputtering

The stability of the electrical, optical and mechanical properties of sputtered zinc oxide (ZnO) thin films with resistivities from 10^?2 to 10^?4 ωcm were investigated. No significant changes in these properties are observed for ZnO films exposed to air at room temperature for 10 months. A change in the electrical resistance of the ZnO films with temperature up to 400 °C is observed in various ambients such as vacuum, inert gases and air. After heat treatment in these ambients at 400 °C, the resistivity of the films increased by one to ten orders of magnitude. The increased resistivity can be returned to the resistivity of the virgin state, within one order of magnitude, by heat treatment in a hydrogen ambient at temperatures near 400 °C. For practical use of ZnO films at high temperatures, the increase in the resistivity might become a disadvantage for ZnO transparent electrodes fabricated by r.f. magnetron sputtering.     

Influence of rapid thermal annealing at varied temperatures on conductivity activation energy and structural properties of Si-doped β-Ga2O3 film grown by pulsed laser deposition

Si-doped β-Ga₂O₃ was generally activated by high-temperature annealing (over 600?°C) due to its strong bonding energy. Considering the electronic applications using β-Ga₂O₃ such as various power devices with low power consumption, it is strongly required to decrease the device process temperature including the impurity activation process. In this article, in order to decrease the impurity activation process temperature, we proposed the rapid thermal annealing (RTA) treatment to activate the Si atoms in the β-Ga₂O₃ films since RTA treatment can give the high thermal energy to specimen in a short time and investigated the influence of RTA treatment with various temperatures on conductivity activation energy, and structural properties of Si-doped β-Ga₂O₃ film. Si-doped β-Ga₂O₃ films were hetero-epitaxially grown on c-plane sapphire substrate by pulsed laser deposition method. Crystallinity, surface roughness, and electrical properties of specimens were investigated by changing the RTA temperatures. Crystallinity and surface roughness of Si-doped β-Ga₂O₃ films were not significantly influenced by RTA treatment at temperatures range of 100–700?°C. Conductivity activation energy of specimens with RTA treatment was about 50–100?meV and did not depend on RTA temperatures. As a result, even Si-doped β-Ga₂O₃ film with RTA treatment at 100?°C showed a relatively good conductivity. Based on the experimental results in this study, it can be said that RTA treatment is useful method to decrease the temperature of activation process for Si-doped β-Ga₂O₃ thin films without serious structural degradations.