Dual Confocal Laser-Induced Fluorescence/Moveable Contactless Conductivity Detector For Capillary Electrophoresis Microchip

A new dual simultaneous detector was developed for capillary electrophoresis microchip. Confocal laser-induced fluorescence (LIF) and moveable contactless conductivity detection (MCCD) were combined together for the first time. The two detection systems shared a common detection cell and could respond simultaneously. They were mutually independent and advantageous in analyses of mixtures containing organic and inorganic ions. The confocal LIF had high sensitivity and the MCCD could move along the separation channel and detect in different positions of the channel. The detection conditions of the dual detector were optimized. Rhodamine B was used to evaluate the performance of the dual detector. The limit of detection of the confocal LIF was < 5 nM, and that of the MCCD was 0.1 mu M. The dual detector had highly sensitivity and could offer response easily, rapidly and simultaneously. 

Dual confocal laser-induced fluorescence/moveable contactless

A new dual simultaneous detector was developed for capillary electrophoresis microchip. Confocal laser-induced fluorescence (LIF) and moveable contactless conductivity detection (MCCD) were combined together for the first time. The two detection systems shared a common detection cell and could respond simultaneously. They were mutually independent and advantageous in analyses of mixtures containing organic and inorganic ions. The confocal LIF had high sensitivity and the MCCD could move along the separation channel and detect in different positions of the channel. The detection conditions of the dual detector were optimized. Rhodamine B was used to evaluate the performance of the dual detector. The limit of detection of the confocal LIF was <5 nM, and that of the MCCD was 0.1 μM. The dual detector had highly sensitivity and could offer response easily, rapidly and simultaneously.

Antikörper: Diseño e implementación de un sistema de detección de intrusos inalámbrico basado en Network IDS

[ES]Este proyecto, fruto de mi Trabajo Fin de Grado, pretende describir los aspectos más relevantes de los Wireless Intrusion Detection System (WIDS), tales como su historia, funcionamiento, arquitecturas, implementación o futuro. Tras esto, se expondrá el objetivo principal del proyecto. Proponer una arquitectura genérica para los WIDS y crear Antikörper, un WIDS basado en Network IDS completamente funcional, que cubra totalmente las necesidades de seguridad actuales en las redes Wireless LAN y sea adaptable a futuras revisiones.

Uso de detectores de dimensões variáveis aplicados na detecção de anomalias através de sistemas imunológicos artificiais.

O presente trabalho investiga um método de detecção de anomalias baseado em sistemas imunológicos artificiais, especificamente em uma técnica de reconhecimento próprio/não-próprio chamada algoritmo de seleção negativa (NSA). Foi utilizado um esquema de representação baseado em hiperesferas com centros e raios variáveis e um modelo capaz de gerar detectores, com esta representação, de forma eficiente. Tal modelo utiliza algoritmos genéticos onde cada gene do cromossomo contém um índice para um ponto de uma distribuição quasi-aleatória que servirá como centro do detector e uma função decodificadora responsável por determinar os raios apropriados. A aptidão do cromossomo é dada por uma estimativa do volume coberto através uma integral de Monte Carlo. Este algoritmo teve seu desempenho verificado em diferentes dimensões e suas limitações levantadas. Com isso, pode-se focar as melhorias no algoritmo, feitas através da implementação de operadores genéticos mais adequados para a representação utilizada, de técnicas de redução do número de pontos do conjunto próprio e de um método de pré-processamento baseado em bitmaps de séries temporais. Avaliações com dados sintéticos e experimentos com dados reais demonstram o bom desempenho do algoritmo proposto e a diminuição do tempo de execução.

Lógica nebulosa aplicada a um sistema de detecção de intrusos em computação em nuvem.

O objetivo deste trabalho é avaliar os riscos de ocorrências de intrusos em um sistema de computação em nuvem para sistemas distribuídos utilizando lógica nebulosa. A computação em nuvem é um tema que vem sendo bastante abordado e vem alavancando discussões calorosas, tanto na comunidade acadêmica quanto em palestras profissionais. Embora essa tecnologia esteja ganhando mercado, alguns estudiosos encontram-se céticos afirmando que ainda é cedo para se tirar conclusões. Isto se deve principalmente por causa de um fator crítico, que é a segurança dos dados armazenados na nuvem. Para esta dissertação, foi elaborado um sistema distribuído escrito em Java com a finalidade de controlar um processo de desenvolvimento colaborativo de software na nuvem, o qual serviu de estudo de caso para avaliar a abordagem de detecção de intrusos proposta. Este ambiente foi construído com cinco máquinas (sendo quatro máquinas virtuais e uma máquina real). Foram criados dois sistemas de inferência nebulosos, para análise de problemas na rede de segurança implementados em Java, no ambiente distribuído. Foram realizados diversos testes com o intuito de verificar o funcionamento da aplicação, apresentando um resultado satisfatório dentro dessa metodologia.

Adaptive modulation induced WDM impairment reduction in optical OFDM PONs

The transmission performance of multi-channel adaptively modulated optical OFDM (AMOOFDM) signals is numerically investigated, for the first time, in optical amplification- and chromatic dispersion compensation-free, intensity-modulation and direct-detection systems incorporating directly modulated DFB lasers (DMLs). It is shown that adaptive modulation not only reduces significantly the nonlinear WDM impairments induced by the effects of cross-phase modulation and four-wave mixing, but also compensates effectively for the DML-induced frequency chirp effect. In comparison with identical modulation, adaptive modulation improves the maximum achievable signal transmission capacity of a central channel by a factor of 1.3 and 3.6 for 40km and 80km SMFs, respectively, with corresponding dynamic input optical power ranges being extended by approximately 5dB. In addition, adaptive modulation also enables cross-channel complementary modulation format mapping, leading to an improved transmission capacity of the entire WDM system. Copyright © 2010 The authors.

Experimental demonstration of real-time optical OFDM Transmission at 7.5 Gb/s over 25-km SSMF using a 1-GHz RSOA

The 7.5-Gb/s real-time end-to-end optical orthogonal frequency-division- multiplexing (OOFDM) transceivers incorporating variable power loading on each individual subcarrier are demonstrated experimentally using a live-optimized reflective semiconductor optical amplifier intensity modulator having a modulation bandwidth as narrow as 1 GHz. Real-time OOFDM signal transmission at 7.5 Gb/s over 25-km standard single-mode fiber is achieved across the $C$-band in simple intensity modulation and direct detection systems without in-line optical amplification and dispersion compensation. © 2006 IEEE.

Film bulk acoustic resonator nanosensors for multi-task sensing

This paper shows that film bulk acoustic resonator (FBAR) arrays can be very useful sensors either to detect physical parameters such as temperature and pressure directly or to detect bio-chemicals with extremely high sensitivities by incorporating a chemisorption layer or bio-probe molecules. Furthermore, it also shows that surface acoustic wave devices can be integrated with a FBAR sensor array on the same piezoelectric substrate as the microfluidics systems to perform transportation and mixing of biosamples etc. demonstrating the possibility to fabricate integrated lab-on-a-chip detection systems, in which all the actuators and sensors are operated by acoustic wave devices. This makes the detection system simple, low cost and easy to operate and hence has great commercial potential. © 2011 Inderscience Enterprises Ltd.

High performance bilayer-graphene Terahertz detectors

© 2014 AIP Publishing LLC. We report bilayer-graphene field effect transistors operating as Terahertz (THz) broadband photodetectors based on plasma-waves excitation. By employing wide-gate geometries or buried gate configurations, we achieve a responsivity ∼1.2 V/W (1.3 mA/W) and a noise equivalent power ∼2 × 10-9 W/√Hz in the 0.29-0.38 THz range, in photovoltage and photocurrent mode. The potential of this technology for scalability to higher frequencies and the development of flexible devices makes our approach competitive for a future generation of THz detection systems.

Wireless and Physical Security via Embedded Sensor Networks

Wireless Intrusion Detection Systems (WIDS) monitor 802.11 wireless frames (Layer-2) in an attempt to detect misuse. What distinguishes a WIDS from a traditional Network IDS is the ability to utilize the broadcast nature of the medium to reconstruct the physical location of the offending party, as opposed to its possibly spoofed (MAC addresses) identity in cyber space. Traditional Wireless Network Security Systems are still heavily anchored in the digital plane of "cyber space" and hence cannot be used reliably or effectively to derive the physical identity of an intruder in order to prevent further malicious wireless broadcasts, for example by escorting an intruder off the premises based on physical evidence. In this paper, we argue that Embedded Sensor Networks could be used effectively to bridge the gap between digital and physical security planes, and thus could be leveraged to provide reciprocal benefit to surveillance and security tasks on both planes. Toward that end, we present our recent experience integrating wireless networking security services into the SNBENCH (Sensor Network workBench). The SNBENCH provides an extensible framework that enables the rapid development and automated deployment of Sensor Network applications on a shared, embedded sensing and actuation infrastructure. The SNBENCH's extensible architecture allows an engineer to quickly integrate new sensing and response capabilities into the SNBENCH framework, while high-level languages and compilers allow novice SN programmers to compose SN service logic, unaware of the lower-level implementation details of tools on which their services rely. In this paper we convey the simplicity of the service composition through concrete examples that illustrate the power and potential of Wireless Security Services that span both the physical and digital plane.

Use of a novel micro-fluidic device to create arrays for multiplex analysis of large and small molecular weight compounds by surface plasmon resonance

There is an increasing demand to develop biosensor monitoring devices capable of biomarker profiling for predicting animal adulteration and detecting multiple chemical contaminants or toxins in food produce. Surface plasmon resonance (SPR) biosensors are label free detection systems that monitor the binding of specific biomolecular recognition elements with binding partners. Essential to this technology are the production of biochips where a selected binding partner, antibody, biomarker protein or low molecular weight contaminant, is immobilised. A micro-fluidic immobilisation device allowing the covalent attachment of up to 16 binding partners in a linear array on a single surface has been developed for compatibility with a prototype multiplex SPR analyser.

The immobilisation unit and multiplex SPR analyser were respectively evaluated in their ability to be fit-for-purpose for binding partner attachment and detection of high and low molecular weight molecules. The multiplexing capability of the dual technology was assessed using phycotoxin concentration analysis as a model system. The parent compounds of four toxin groups were immobilised within a single chip format and calibration curves were achieved. The chip design and SPR technology allowed the compartmentalisation of the binding interactions for each toxin group offering the added benefit of being able to distinguish between toxin families and perform concentration analysis. This model is particularly contemporary with the current drive to replace biological methods for phycotoxin screening.

Obfuscation: The Hidden Malware

A cyberwar exists between malware writers and antimalware researchers. At this war's heart rages a weapons race that originated in the 80s with the first computer virus. Obfuscation is one of the latest strategies to camouflage the telltale signs of malware, undermine antimalware software, and thwart malware analysis. Malware writers use packers, polymorphic techniques, and metamorphic techniques to evade intrusion detection systems. The need exists for new antimalware approaches that focus on what malware is doing rather than how it's doing it.

Uptake, translocation and transformation of arsenate and arsenite in sunflower (Helianthus annuus):formation of arsenic-phytochelatin complexes during exposure to high arsenic concentrations

The aim of the study was to determine the time-dependent formation of arsenic-phytochelatin (As-PC) complexes in the roots, stems and leaves of an arsenic-nontolerant plant (Helianthus annuus) during exposure to 66 mol l(-1) arsenite (As(III)) or arsenate (As(V)). We used our previously developed method of simultaneous element-specific (inductively coupled plasma mass spectrometry, ICP-MS) and molecular-specific (electrospray-ionization mass spectrometry, ES-MS) detection systems interfaced with a suitable chromatographic column and eluent conditions, which enabled us to identify and quantify As-PC complexes directly. Roots of As-exposed H. annuus contained up to 14 different arsenic species, including the complex of arsenite with two (gamma-Glu-Cys)(2)-Gly molecules [As((III))-(PC(2))(2)], the newly identified monomethylarsonic phytochelatin-2 or (gamma-Glu-Cys)(2)-Gly CH(3)As (MA((III))-PC(2)) and at least eight not yet identified species. The complex of arsenite with (gamma-Glu-Cys)(3)-Gly (As((III))-PC(3)) and the complex of arsenite with glutathione (GSH) and (gamma-Glu-Cys)(2)-Gly (GS-As((III))-PC(2)) were present in all samples (roots, stems and leaves) taken from plants exposed to As. The GS-As((III))-PC(2) complex was the dominant complex after 1 h of exposure. As((III))-PC(3) became the predominant As-PC complex after 3 h, binding up to 40% of the As present in the exposed plants. No As-PC complexes were found in sap (mainly xylem sap from the root system), in contrast to roots, stems and leaves, which is unequivocal evidence that As-PC complexes are not involved in the translocation of As from root to leaves of H. annuus.

The nature of arsenic-phytochelatin complexes in Holcus lanatus and Pteris cretica

We have developed a method to extract and separate phytochelatins (PCs)-metal(loid) complexes using parallel metal(loid)-specific (inductively coupled plasma-mass spectrometry) and organic-specific (electrospray ionization-mass spectrometry) detection systems-and use it here to ascertain the nature of arsenic (As)-PC complexes in plant extracts. This study is the first unequivocal report, to our knowledge, of PC complex coordination chemistry in plant extracts for any metal or metalloid ion. The As-tolerant grass Holcus lanatus and the As hyperaccumulator Pteris cretica were used as model plants. In an in vitro experiment using a mixture of reduced glutathione (GS), PC(2), and PC(3), As preferred the formation of the arsenite [As((III))]-PC(3) complex over GS-As((III))-PC(2), As((III))-(GS)(3), As((III))-PC(2), or As((III))-(PC(2))(2) (GS: glutathione bound to arsenic via sulphur of cysteine). In H. lanatus, the As((III))-PC(3) complex was the dominant complex, although reduced glutathione, PC(2), and PC(3) were found in the extract. P. cretica only synthesizes PC(2) and forms dominantly the GS-As((III))-PC(2) complex. This is the first evidence, to our knowledge, for the existence of mixed glutathione-PC-metal(loid) complexes in plant tissues or in vitro. In both plant species, As is dominantly in non-bound inorganic forms, with 13% being present in PC complexes for H. lanatus and 1% in P. cretica.

Fault Diagnostics for Internal Combustion Engines – Current and Future Techniques

The adoption of each new level of automotive emissions legislation often requires the introduction of additional emissions reduction techniques or the development of existing emissions control systems. This, in turn, usually requires the implementation of new sensors and hardware which must subsequently be monitored by the on-board fault detection systems. The reliable detection and diagnosis of faults in these systems or sensors, which result in the tailpipe emissions rising above the progressively lower failure thresholds, provides enormous challenges for OBD engineers. This paper gives a review of the field of fault detection and diagnostics as used in the automotive industry. Previous work is discussed and particular emphasis is placed on the various strategies and techniques employed. Methodologies such as state estimation, parity equations and parameter estimation are explained with their application within a physical model diagnostic structure. The utilization of symptoms and residuals in the diagnostic process is also discussed. These traditional physical model based diagnostics are investigated in terms of their limitations. The requirements from the OBD legislation are also addressed. Additionally, novel diagnostic techniques, such as principal component analysis (PCA) are also presented as a potential method of achieving the monitoring requirements of current and future OBD legislation.