Measuring vulnerabilities and their exploitation cycle

In a world ruled by chaotic causality, Heisenberg's uncertainty principle is only a natural limitation. Analysts only have their personal logic, experience and intuition to depend on in order to make judgments regarding the safety of a system. However, today's analysts are getting bombarded with large amounts of data coming from all kinds of security-related products, such as vulnerability scanners, anti-viruses, firewalls etc, causing information overload and data congestion. Thus, the question remains: How can analysts make a correct judgment regarding the vulnerabilities from which a system is suffering, especially when all the ammunition he/she possesses can not deal with such a complex, ever-changing environment? To this end, we believe that structuring knowledge/information regarding a specific domain in an object-oriented hierarchy tree, and providing a formal model to reason and construct possible scenarios of attacks, will provide an analyst with the necessary ammunition.     

In situ hydrogen utilization in an internal reforming methanol fuel cell

In this work, we report on the catalytic properties of a novel ultrathin methanol reformer incorporated into the anode compartment of a High Temperature PEM Fuel Cell (HT-PEMFC). A highly active Cu-based methanol reforming catalyst (HiFuel R120, Johnson Matthey) was deposited on the gas diffusion layer of a carbon paper and the influence of anode flow distribution through the catalytic bed was studied in the temperature range of 160–220 °C. Inhibition by produced H₂ is higher in the case of through plane flow, especially in more concentrated methanol feeds. Higher methanol conversions were achieved with the in-plane flow distribution along the catalytic bed (>98% at 210 °C and without any deactivation for at least 100 h test), with a 50 cm² reformer (total thickness = 600 μm). The corresponding Internal Reforming Methanol Fuel Cell (IRMFC) operated efficiently for more than 72 h at 210 °C with a cell voltage of 642 mV at 0.2 A cm⁻², when 30% CH₃OH/45% H₂O/He (anode feed) and pure O₂ (cathode feed) were supplied.     

Joint order and parameter estimation of multivariate autoregressive models using multi-model partitioning theory

In this paper the multi-model partitioning theory is used for simultaneous order and parameter estimation of multivariate autoregressive models. Simulation experiments show that the proposed method successfully selects the correct model order and estimates the parameters accurately, in very few steps, even with a small sample size. They also show that the proposed method performs equally well when the complexity of the model is increased. The results are compared to those obtained using well-established order selection criteria. Finally, it is shown that the method is also successful in tracking model order changes, in real time.     

Inter-autonomous system provisioning for end-to-end bandwidth guarantees

This paper addresses the issue of provisioning end-to-end bandwidth guarantees across multiple Autonomous Systems (ASes). We first review a cascaded model for negotiating and establishing service level agreements for end-to-end bandwidth guarantees between ASes. We then present a network dimensioning system that uses traffic engineering mechanisms for the provisioning of end-to-end bandwidth guarantees. The network dimensioning system solves two problems: (1) the economic problem of how to determine the optimum amount of bandwidth that needs to be purchased from adjacent downstream ASes at a minimum total cost; (2) given the available bandwidth resources within and beyond the AS as a result of (1), the engineering problem of how to assign bandwidth guaranteed routes to the predicted traffic while optimizing the network resource utilization. We formulate both as integer-programming problems and prove them to be NP-hard. An efficient genetic algorithm and an efficient greedy-penalty heuristic are, respectively, used to solve the two problems and we show that these perform significantly better than simple heuristic and random approaches.     

Detection of chromosomal and plasmid--encoded virulence determinants in Yersinia enterocolitica and other Yersinia spp. isolated from food animals in Greece

The distribution of Yersinia strains in animal reservoirs was examined in 835 food animals (pigs, chickens, sheep, cows) from different Greek departments (Attica, Fthiotida, Viotia and Evia) over a one year period. The isolated strains were characterized with respect to the presence of chromosomal (yst) and plasmid-encoded virulence determinants (virF, yadA) and their antimicrobial susceptibility was tested.In total, Yersiniaspp. were obtained from 9.94% of the 835 food animals at slaughter that were sampled in this study. There was no statistically significant seasonal distribution, nor was any significant departmental distribution observed. From the 83 isolated Yersinia strains, 76 (91,57%) belonged to Y. enterocolitica (58 were of serotype O:3/biotype 4 and 18 strains were non O:3, non O:9), 3 belonged to Y. pseudotuberculosis, 2 to Y. kristensenii and 2 to Y. intermedia. Y. enterocolitica O:3/4 was mainly isolated from the pigs, while Y. enterocolitica non O:3, non O:9 was from the chickens. The strains were grouped into 5 genotypes, with respect to the presence or absence of the virulence genes. A significant predominance of genotype V, the one carrying all the three virulence genes, was observed in the strains isolated from the pigs. Complete susceptibility to most of the 3rd and to the 4th generation cephalosporins and to ciprofloxacin, was observed among the isolates. Remarkable was the association between the presence of each virulence gene separately and resistance to some antimicrobials, a matter of further investigation.     

Outcome Prediction in Critically-Ill Patients with Venous Thromboembolism and/or Cancer Using Machine Learning Algorithms: External Validation and Comparison with Scoring Systems

Intensive care unit (ICU) patients with venous thromboembolism (VTE) and/or cancer suffer from high mortality rates. Mortality prediction in the ICU has been a major medical challenge for which several scoring systems exist but lack in specificity. This study focuses on two target groups, namely patients with thrombosis or cancer. The main goal is to develop and validate interpretable machine learning (ML) models to predict early and late mortality, while exploiting all available data stored in the medical record. To this end, retrospective data from two freely accessible databases, MIMIC-III and eICU, were used. Well-established ML algorithms were implemented utilizing automated and purposely built ML frameworks for addressing class imbalance. Prediction of early mortality showed excellent performance in both disease categories, in terms of the area under the receiver operating characteristic curve (AUC–ROC): VTE-MIMIC-III 0.93, eICU 0.87, cancer-MIMIC-III 0.94. On the other hand, late mortality prediction showed lower performance, i.e., AUC–ROC: VTE 0.82, cancer 0.74–0.88. The predictive model of early mortality developed from 1651 VTE patients (MIMIC-III) ended up with a signature of 35 features and was externally validated in 2659 patients from the eICU dataset. Our model outperformed traditional scoring systems in predicting early as well as late mortality. Novel biomarkers, such as red cell distribution width, were identified.     

Diagnostic Performance of Pancreatic Cytology with the Papanicolaou Society of Cytopathology System: A Systematic Review,before Shifting into the Upcoming WHO International System

The Papanicolaou Society of Cytopathology (PSC) reporting system classifies pancreatobiliary samples into six categories (I–VI), providing guidance for personalized management. As the World Health Organization (WHO) has been preparing an updated reporting system for pancreatobiliary cytopathology, this systematic review aimed to evaluate the risk of malignancy (ROM) of each PSC category, also the sensitivity and specificity of pancreatic FNA cytology using the current PSC system. Five databases were investigated with a predefined search algorithm. Inclusion and exclusion criteria were applied to select the eligible studies for subsequent data extraction. A study quality assessment was also performed. Eight studies were included in the qualitative analysis. The ROM of the PSC categories I, II, III, IV, V, VI were in the ranges of 8–50%, 0–40%, 28–100%, 0–31%, 82–100%, and 97–100%, respectively. Notably, the ROM IVB (“neoplastic—benign”) subcategory showed a 0% ROM. Four of the included studies reported separately the ROMs for the IVO subcategory (“neoplastic—other”; its overall ROM ranged from 0 to 34%) with low (LGA) and high-grade atypia (HGA). ROM for LGA ranged from 4.3 to 19%, whereas ROM for HGA from 64 to 95.2%. When the subcategory IVO with HGA was considered as cytologically positive, together with the categories V and VI, there was a higher sensitivity of pancreatic cytology, at minimal expense of the specificity. Evidence suggests the proposed WHO international system changes—shifting the IVB entities into the “benign/negative for malignancy” category and establishing two new categories, the “pancreatic neoplasm, low-risk/grade” and “pancreatic neoplasm, high-risk/grade”—could stratify pancreatic neoplasms more effectively than the current PSC system.     

Hybrid channel coding scheme for blind space-time coded MIMO systems

This letter proposes a hybrid use of channel codes in wireless systems employing multiple transmit/multiple receive antennas. We concatenate space-time codes (STCs) serially with low-density parity check (LDPC) codes and turbo codes. We show that by using these powerful coding schemes effectively, substantial performance improvements can be achieved. This is motivated by the need for a scheme that gives promising performance even when no training is available. The proposed scheme results in a desirable trade-off between performance and complexity.     

Hardware Architectures for the Efficient Implementation of Multi-Service Broadband Access and Multimedia Home Networks

In multimedia applications, the stringent requirements for balancing transmission capacity, flexible service provisioning and cost reduction lead the manufactures to provide highly integrated System-on Chip (SoC) solutions. This paper analyzes the application of high-bandwidth-networking SoCs to improve on the cost efficiency of multimedia service distribution in home networks. We present a case study, where we utilize the inherent protocol processing capabilities and high bandwidth interfaces of a modern network processor, scaled down to match the performance targets and low cost requirements of the home networking environment. An efficient, low cost Residential Gateway architecture results by mapping the home services onto the processing and memory blocks of this SoC. This revised version was published online in September 2006 with corrections to the Cover Date.