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.     

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.     

Validation and improvement of gamma heating calculation methods for the G.A. Siwabessy multipurpose reactor

Nuclear Science and Techniques - This study presents the RF design of a linear accelerator (linac) operated in single-bunch mode. The accelerator is powered by a compressed RF pulse produced from a...     

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.     

Manufacture of three-layer wood–porcelain stone composite board reinforced with bamboo fiber

The objective of this study was to improve bending strength properties of three-layer wood–porcelain stone composite board. The focus of this study was on the effects of orientations and weight ratios of bamboo fiber in face layer on physical and mechanical properties of the board. Three types of board with different orientation of bamboo fibers in the face layer were manufactured: one in which the fibers were oriented at random orientation (R board), another in which the fibers were oriented at unidirectional orientation (U board), and a third in which the fibers were oriented at cross orientation (C board). The physical and mechanical properties of the boards were evaluated based on the Japanese Industrial Standard for Particleboards. The main results obtained were as follows: Bending strength properties of the board were strongly affected by both orientation and weight ratio of bamboo fibers. Perpendicular specimen of C board has larger bending strength properties than U board and the value become larger with increased weight ratio of bamboo fibers. Internal bond strength value decreased with increasing weight ratio of bamboo fibers. The effect of orientation and weight ratios of bamboo fiber on thickness swelling of the board was not significant.     

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.     

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.     

SnO-SnO2 modified two-dimensional MXene Ti3C2Tx for acetone gas sensor working at room temperature

Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,the nanocomposite combining SnO-SnO2 (p-n junction) and Ti3C2Tx MXene was successfully synthesized by a one-step hydrothermal method.Because of the existence of a small amount of oxygen during the hydrothermal conditions,part of the p-type SnO was oxidized to n-type SnO2,forming in-situ p-n junctions on the surface of SnO.The hamburger-like SnO-SnO2/Ti3C2Tx sensor exhibited improved acetone gas sensing response of 12.1 (Rg/Ra) at room temperature,which were nearly 11 and 4 times higher than those of pristine Ti3C2Tx and pristine SnO-SnO2,respectively.Moreover,it expressed a short recovery time (9 s) and outstanding reproducibility.Because of the different work functions,the Schottky barrier was formed between the SnO and the Ti3C2Tx nanosheets,acting as a hole accumulation layer (HALs) between Ti3C2Tx and tin oxides.Herein,the sensing mechanism based on the formation of hetero-junctions and high conductivity of the metallic phase of Ti3C2Tx MXene in SnO-SnO2/Ti3C2Tx sensors was discussed in detail.     

A Low Temperature Route toward Hierarchically Structured Titania Films for Thin Hybrid Solar Cells

The requirement of high‐temperature calcination for titanium dioxide in (solid‐state) dye‐sensitized solar cells (DSSCs) implies challenges with respect to reduced energy consumption and the potential for flexible photovoltaic devices. Moreover, the use of dye molecules increases production costs and leads to problems related with dye bleaching. Therefore, fabrication of dye‐free hybrid solar cells at low temperature is a promising alternative for current DSSC technology. In this work the authors fabricate hierarchically structured titania thin films by combining a polystyrene‐block‐polyethylene oxide template assisted sol–gel synthesis with nano‐imprint lithography at low temperatures. The achieved films are filled with poly(3‐hexylthiophene) to form the active layer of hybrid solar cells. The surface morphology is probed via scanning electron microscopy and atomic force microscopy, and the bulk film morphology is examined with grazing incidence X‐ray scattering. Good light absorption by the active layer is proven by UV–vis spectroscopy. An enhancement in light absorption is observed and ascribed to light scattering in mesoporous titania films with imprinted superstructures. Accordingly a better photovoltaic performance is found for nano‐imprinted solar cells at various angles of light incidence.