On the optimal,fair and channel-aware cognitive radio network reconfiguration

In this work, we focus on the Joint Channel Assignment and Routing (JCAR) problem in Cognitive Radio Networks (CRNs) and especially on the optimal reconfiguration of secondary networks under the presence of primary users. Secondary CRN users need to adapt their transmission channels promptly, while effectively limit additional or escalating system modifications triggered by the intertweaved primary user activity. Our approach takes into consideration the underlying spectrum switching dynamics and concurrently aims at a fair resource allocation among the active network flows. We take an optimization perspective and formulate the JCAR and network reconfiguration problems as mixed integer linear programs, addressing fairness concerns as well. We propose a heuristic approach which is based on a sequential reduced search space methodology, in order to obtain efficiently solutions of otherwise tough and demanding reconfiguration problems. The operation, effectiveness and performance of the proposed mechanisms are evaluated through analysis and simulations under various working conditions. The obtained numerical results indicate the benefits of the proposed schemes in terms of overhead performance and their scaling properties with respect to more realistic and thus demanding topologies.     

A case study on bypass testing of web applications

Society’s increasing reliance on services provided by web applications places a high demand on their reliability. The flow of control through web applications heavily depends on user inputs and interactions, so user inputs should be thoroughly validated before being passed to the back-end software. Although several techniques are used to validate inputs on the client, users can easily bypass this validation and submit arbitrary data to the server. This can cause unexpected behavior, and even allow unauthorized access. A test technique called bypass testing intentionally sends invalid data to the server by bypassing client-side validation. This paper reports results from a comprehensive case study on 16 deployed, widely used, commercial web applications. As part of this project, the theory behind bypass testing was extended and an automated tool, AutoBypass, was built. The case study found failures in 14 of the 16 web applications tested, some significant. This study gives evidence that bypass testing is effective, has positive return on investment, and scales to real applications.     

Embracing RaptorQ FEC in 3GPP multicast services

Multimedia Broadcast/Multicast Services (MBMS) have been introduced by Third Generation Partnership Project (3GPP) aiming to efficiently deliver data to mobile users in a one-to-many way. In order to provide reliable multicast transmission, 3GPP recommends exclusively for MBMS the use of a Forward Error Correction (FEC) mechanism on the application layer. Raptor codes are standardized as the Application Layer FEC (AL-FEC) scheme over 3GPP MBMS. However, the 3GPP standardized systematic fountain Raptor code is nowadays considered obsolete, since a new variation of the Raptor codes has emerged. This enhanced AL-FEC scheme, named RaptorQ, promises higher protection efficiency and superior flexibility on the provision of demanding mobile multicast services. In this work, we provide an extensive performance evaluation presenting at first a theoretical performance comparison of the newly introduced RaptorQ FEC scheme with its predecessor Raptor code, examining the enhancements that RaptorQ introduces on the AL-FEC protection robustness. Thereafter, to verify the enhanced performance of RaptorQ, we present several simulation results considering the modeling of the AL-FEC protection over multicast services for next generation mobile networks, utilizing the ns-3 simulation environment. Investigating several mobile system parameters in conjunction with FEC encoding parameters, we provide valuable results regarding the impacts of the examined AL-FEC schemes application on the multicast services performance.     

Binding of the Phage Display Derived Peptide CaIX-P1 on Human Colorectal Carcinoma Cells Correlates with the Expression of Carbonic Anhydrase IX

Phage display represents an attractive screening strategy for the identification of novel, specific binding ligands that could be used for tumor targeting. Recently, a new peptide (CaIX-P1) with affinity for human carbonic anhydrase IX (CAIX) was identified and evaluated. The aim of the present study is to characterize the properties of CaIX-P1 for targeting human colorectal carcinoma and investigate the correlation of peptide binding with the expression of carbonic anhydrase IX. Human colorectal carcinoma HCT116 and HT29 cells were investigated for CAIX expression using Western Blot analysis. Binding and competition studies of ¹²⁵I-radiolabeled CaIX-P1 were performed on HCT116 cells in vitro. FACS analysis and fluorescence microscopy studies were carried out after cell incubation with fluorescein-labeled CaIX-P1 and rhodamine-labeled anti-human CAIX-mAb. Our studies revealed an enhanced in vitro expression of carbonic anhydrase IX in HCT116 and HT29 cells with increasing cell density. Binding of ¹²⁵I-labeled-CaIX-P1 on HCT116 cells increased with increasing cell density and correlated to the CAIX expression. FACS analysis demonstrated a correlation of cell labeling between FITC-CaIX-P1 and rhodamine-labeled anti-CAIX-mAb in both HCT116 and HT29 cells. The results of our study indicate that the phage display identified peptide CaIX-P1 might be an attractive candidate for the development of a ligand targeting CAIX in colorectal cancer.     

Antioxidant and free radical-scavenging activities of phenolic extracts of olive fruits

The antioxidant ability of phenolic extracts of olive fruits during maturity in Chondrolia and Amfissis cultivars grown at 10 m and 300 m altitude showed that altitude affected phenol content, antioxidant and Fe²⁺/Fe³⁺ reduction/binding ability. The hydroxyl radical, peroxyl radical and peroxynitrite-induced DNA nicking assays have been used to evaluate the anti-radical activity of the extracts. Results showed that the ability of olive extracts to prevent radical-mediated DNA damage arises from the triple synergistic action of the genotype, the altitude and the maturation stage.     

Old and endangered tomato cultivars under organic greenhouse production: effect of harvest time on flavour profile and consumer acceptance

The influence of two different harvest times (optimal and 4 days earlier) on thirty flavour compounds, titratable acid and sugars as well as consumer acceptance of four old and endangered tomato cultivars (‘Ananas’, ‘Auriga’, ‘Green Zebra’ and ‘Lukullus’) was analysed. In most cases, cultivar type had a greater effect on the volatiles profile than harvest times. Sugar contents were mostly higher at optimal harvest compared with early harvest, whereas acid content was in most cases not affected by harvest time. Consumers perceived differences in several visual and sensory aspects between cultivars as well as harvest times. The optimal harvest was regularly preferred to or at least regarded as equal to the early‐harvest time. Sensory evaluation was poorly related to the aroma volatile profile and only partly to the acid and reducing sugar contents of tomatoes. This was probably owing to the special external characteristics of the tomatoes: differing in size, shape and colour from the ‘normal’ red types.     

Validation of a Loop-Mediated Amplification/ISO 6579-Based Method for Analysing Soya Meal for the Presence of <Emphasis Type="Italic">Salmonella enterica</Emphasis>

An alternative method for detection of Salmonella spp. in animal feed, based on the use of loop-mediated amplification (LAMP) in conjunction with a standard culturing procedure, was compared with the standard ISO 6579 as reference method, using soya meal as the test matrix. In the method comparison study, the sensitivities for both the alternative and reference methods were 100 %. The relative level of detection was 1.000. Tested against 100 Salmonella and 30 non-Salmonella strains, the LAMP-based method was 99 % inclusive and 100 % exclusive. The interlaboratory trial involved ten laboratories from eight European countries, testing eight samples at three contamination levels: 0 cfu/100 g, 1–5 cfu/100 g and 14–68 cfu/100 g. The trial specificity, or percentage correct identification of uncontaminated samples, was 96.3 % for both the reference methods and the LAMP/ISO 6579 alternative method, thus demonstrating its suitability for adoption as a procedure for rapid identification of Salmonella uncontaminated soya meal.     

On data mining,compression, and Kolmogorov complexity

Will we ever have a theory of data mining analogous to the relational algebra in databases? Why do we have so many clearly different clustering algorithms? Could data mining be automated? We show that the answer to all these questions is negative, because data mining is closely related to compression and Kolmogorov complexity; and the latter is undecidable. Therefore, data mining will always be an art, where our goal will be to find better models (patterns) that fit our datasets as best as possible.