326 research outputs found

    Determination of Saxitoxin by Receptor Binding Assay: A New Radiolabeled Kit in Thailand

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    Objective: A receptor binding assay for detection of saxitoxin, a paralytic shellfish poisoning toxin, was formatted for use in a high throughputdetection system using microplate scintillation counting. The RBA technology was transferred from the NOAA National Ocean Service, SC USA, tothe Thailand Institute of Nuclear Technology, which uses a Perkin Elmer Microbeta TriLux 1450 microplate scintillation counter. Methods: Validationof method was performed by participating in the regional inter-laboratory program. The result yielded all parameters within the critical control point(i.e. RSD less than 30%). Results: The slope of the calibration graph = 1.2 + 0.26 (RSD = 21.7%) (criteria = 0.8 - 1.2), half maximal inhibition (IC50)= 3.1 + 0.47 nM (RSD = 15.2%) (criteria = 3.0 nM), dynamic range = 1.2 - 10 nM and the limit of detection (IC80) from graph = 1.2 nM, equivalentto the limit of quantification of 2.57 mg/100 g shellfish. The result of analysis of unknown samples yielded the RSD between assays ranging from 6 -23% and the recovery compared to the expected value ranging from 79 -133%. The application of RBA for determination of PSP in shellfish samplesyielded RSD in assays less than 30% and between assays ranging from 1.4-15.2%. Conclusion: RBA for STX has showed a valuable for rapid,reliable, cost-effective alternative to live animal testing and high throughput screen prior to testing by the conventional mouse bioassay (MBA) and itssuitability for providing an early warning of increasing PSP toxicity when toxin levels are below the MBA limit of detection.Keywords: saxitoxin, receptor binding assay, paralytic shellfish poisoning, tritiumThai Pharm Health Sci J 2010;5(4):287-295

    Synchronization Techniques for Burst-Mode Continuous Phase Modulation

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    Synchronization is a critical operation in digital communication systems, which establishes and maintains an operational link between transmitter and the receiver. As the advancement of digital modulation and coding schemes continues, the synchronization task becomes more and more challenging since the new standards require high-throughput functionality at low signal-to-noise ratios (SNRs). In this work, we address feedforward synchronization of continuous phase modulations (CPMs) using data-aided (DA) methods, which are best suited for burst-mode communications. In our transmission model, a known training sequence is appended to the beginning of each burst, which is then affected by additive white Gaussian noise (AWGN), and unknown frequency, phase, and timing offsets. Based on our transmission model, we derive the Cramer-Rao bound (CRB) for DA joint estimation of synchronization parameters. Using the CRB expressions, the optimum training sequence for CPM signals is proposed. It is shown that the proposed sequence minimizes the CRB for all three synchronization parameters asymptotically, and can be applied to the entire CPM family. We take advantage of the simple structure of the optimized training sequence in order to design a practical synchronization algorithm based on the maximum likelihood (ML) principles. The proposed DA algorithm jointly estimates frequency offset, carrier phase and symbol timing in a feedforward manner. The frequency offset estimate is first found by means of maximizing a one dimensional function. It is then followed by symbol timing and carrier phase estimation, which are carried out using simple closed-form expressions. We show that the proposed algorithm attains the theoretical CRBs for all synchronization parameters for moderate training sequence lengths and all SNR regions. Moreover, a frame synchronization algorithm is developed, which detects the training sequence boundaries in burst-mode CPM signals. The proposed training sequence and synchronization algorithm are extended to shaped-offset quadrature phase-shift keying (SOQPSK) modulation, which is considered for next generation aeronautical telemetry systems. Here, it is shown that the optimized training sequence outperforms the one that is defined in the draft telemetry standard as long as estimation error variances are considered. The overall bit error rate (BER) plots suggest that the optimized preamble with a shorter length can be utilized such that the performance loss is less than 0.5 dB of an ideal synchronization scenario

    Operating an Advertising Programmatic Buying Platform: A Case Study

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    This paper analyses how new technological developments and the possibilities generated by the internet are shaping the online advertising market. More specifically it focuses on a programmatic advertising case study. The origin of the problem is how publishers resort to automated buying and selling when trying to shift unsold inventory. To carry out our case study, we will use a programmatic online advertising sales platform, which identifies the optimal way of promoting a given product. The platform executes, evaluates, manages and optimizes display advertising campaigns, all in real-time. The empirical analysis carried out in the case study reveals that the platform and its exclusion algorithms are suitable mechanisms for analysing the performance and efficiency of the various segments that might be used to promote products. Thanks to Big Data tools and artificial intelligence the platform performs automatically, providing information in a user-friendly and simple manner

    Reactive scheduling to treat disruptive events in the MRCPSP

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    Esta tesis se centra en diseñar y desarrollar una metodología para abordar el MRCPSP con diversas funciones objetivo y diferentes tipos de interrupciones. En esta tesis se exploran el MRCPSP con dos funciones objetivo, a saber: (1) minimizar la duración del proyecto y (2) maximizar el valor presente neto del proyecto. Luego, se tiene en cuenta dos tipos diferentes de interrupciones, (a) interrupción de duración, e (b) interrupción de recurso renovable. Para resolver el MRCPSP, en esta tesis se proponen tres estrategias metaheurísticas: (1) algoritmo memético para minimizar la duración del proyecto, (2) algoritmo adaptativo de forrajeo bacteriano para maximizar el valor presente neto del proyecto y (3) algoritmo de optimización multiobjetivo de forrajeo bacteriano (MBFO) para resolver el MRCPSP con eventos de interrupción. Para juzgar el rendimiento del algoritmo memético y de forrajeo bacteriano propuestos, se ha llevado a cabo un extenso análisis basado en diseño factorial y diseño Taguchi para controlar y optimizar los parámetros del algoritmo. Además se han puesto a prueba resolviendo las instancias de los conjuntos más importantes en la literatura: PSPLIB (10,12,14,16,18,20 y 30 actividades) y MMLIB (50 y 100 actividades). También se ha demostrado la superioridad de los algoritmos metaheurísticos propuestos sobre otros enfoques heurísticos y metaheurísticos del estado del arte. A partir de los estudios experimentales se ha ajustado la MBFO, utilizando un caso de estudio.DoctoradoDoctor en Ingeniería Industria

    Joint phase-recovery and demodulation-decoding of AIS signals received by satellite

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    International audienceThis paper presents a demodulation algorithm for automatic identification system (AIS) signals received by a satellite. The main contribution of this work is to consider the phase recovery problem for an unknown modulation index, coupled with a time-varying phase shift. The proposed method is based on a demodulator introduced in a previous paper based on a Viterbi-type algorithm applied to an extended trellis. The states of this extended trellis are composed of a trellis-code state and of a cyclic redundancy check state. The bit stuffing mechanism is taken into account by defining special conditional transitions in the extended trellis. This algorithm estimates and tracks the phase shift by modifying the Euclidean distance used in the trellis. Simulation results obtained with and without phase tracking are presented and compared in the context of the AIS system

    Design, Development, and Validation of an Augmented Reality-Enabled Production Strategy Process

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    The Production Strategy Process (PSP) is an integral part of production planning and control as it defines how production processes are structured and designed and outlines how production will be executed. PSP involves massive information transfer and communication among project participants. While BIM can improve the flow of information, the paradox of designing 3D models in 2D space remains. This paradox indicates that new visualization technologies are needed to leverage the use of information in the PSP. As Industry 4.0, the fourth industrial revolution, continues to evolve, it is imperative that construction firms seek, find, and adopt new technologies. This research employed Augmented Reality (AR) as a new user interface in the PSP. The current state of practice of PSP was investigated and current challenges are identified. The opportunities to integrate AR were defined, and an AR-enabled future state was proposed. Next, an AR-enabled PSP prototype using the Microsoft HoloLens was implemented and validated on a real-world healthcare project. Usability testing was then conducted using a one-on-one protocol to validate the prototype with 20 participants. Surveys were the deployed to qualitatively assess the impact of integrating AR into PSP. The difference between the traditional PSP and the AR-enabled PSP was tested through a series of hypotheses comparing both processes. The results demonstrate that the AR-enabled PSP offers significant benefits over the Traditional PSP: improved collaboration, reduced miscommunication, increased quality and detection of errors, enhanced decision-making, better documentation, better information access, improved information flow, increased input accuracy, and increased integration of safety considerations. Additionally, the technology, software, and hardware were also evaluated, and, on average, the findings demonstrated the potential of AR in production planning

    Power-management policies for mobile computing

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    Abbiamo studiato architetture di rete per il power-saving in ambito di wireless LAN infrastrutturate. Abbiamo proposto protocolli power-saving di livello middleware, indipendenti dalla tecnologia wireless impiegata. Tali protocolli sono stati valutati approfonditamente, risultando molto efficienti. Abbiamo poi valutato in maniera estensiva il meccanismo di power-saving dello standard 802.11. Ne abbiamo evidenziato i limiti, ed abbiamo definito un framework cross-layer di power-management. Tale framewok integra i protocolli middleware studiati inizialmente e lo standard 802.11. L'incremento delle prestazioni ottenute rispetto allo standard 802.11 arriva al 90% in termini di power saving
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