A new fibre optic pulse oximeter probe for monitoring splanchnic organ arterial blood oxygen saturation

A new, continuous method of monitoring splanchnic organ oxygen saturation (SpO(2)) would make the early detection of inadequate tissue oxygenation feasible, reducing the risk of hypoperfusion, severe ischaemia, and, ultimately, death. In an attempt to provide such a device, a new fibre optic based reflectance pulse oximeter probe and processing system were developed followed by an in vivo evaluation of the technology on seventeen patients undergoing elective laparotomy. Photoplethysmographic (PPG) signals of good quality and high signal-to-noise ratio were obtained from the small bowel, large bowel, liver and stomach. Simultaneous peripheral PPG signals from the finger were also obtained for comparison purposes. Analysis of the amplitudes of all acquired PPG signals indicated much larger amplitudes for those signals obtained from splanchnic organs than those obtained from the finger. Estimated SpO(2) values for splanchnic organs showed good agreement with those obtained from the finger fibre optic probe and those obtained from a commercial device. These preliminary results suggest that a miniaturized 'indwelling' fibre optic sensor may be a suitable method for pre-operative and post-operative evaluation of splanchnic organ SpO(2) and their health.     

Differential lidar fluorosensor system used for phytoplankton bloom and seawater quality monitoring in Antarctica

A mobile fluorosensor system has been built to participate in oceanographic campaigns. During the first mission, carried out within the XIII Italian Antarctic Expedition (Research Vessel Italica, November 1997 to January 1998), seawater quality parameters (phytoplankton concentration, yellow matter, turbidity and biomass productivity) were remotely and locally monitored both in the Ross Sea and along the route back to New Zealand. Data were georeferenced by means of a GPS recorder to be subsequently plotted on thematic maps. The core of the system is a compact lidar fluorosensor capable of single or dual laser excitation of the target. In the single excitation mode, the detection of chromophores peculiar to various water impurities is possible, while dual laser excitation is necessary to monitor the phytoplankton photosynthetic activity on the chlorophyll emission channel. A lamp spectrofluorometer, a pulsed amplitude fluorometer (PAM) and a solar radiance detector completed the set of instruments onboard.     

A real-time flood-routed voice protocol for fibre optic local area networks

A simple real-time flood routing voice (RTFRV) protocol which is suitable for point-to-point arbitrarily connected fibre optic local area networks is described. Simulation on a 3 Mbit/s nine-node mesh network which employs the protocol has shown that it is capable of supporting about 50 simultaneous two-way voice conversations (or 100 users) with packet delay of less than 10 ms and without any loss of information. The overall results suggest that voice transmission on such a network is feasible and that it performs better than voice transmission over Ethernet. Furthermore, the network is also very robust and allows easy network reconfiguration.     

Laser-induced marine bioluminescence measurements and the potential for airborne remote sensing

Bioluminescence in cultures of the dinoflagellate Pyrocystis lunula at various temperatures were stimulated using a pulsed dye laser and Rhodamine 6G dye having an optimum lasing wavelength of $\text{586 ± 30}\text{nm}$. Following an intense “first flash” response, the flash intensity decayed in logarithmic fashion with successive laser shots. Samples pulsed to exhaustion were found to completely recover during the 12 h photophase. The total stimulable light (TSL) was calculated to be between $\text{4.5 × 10}{}^{\mathrm{?10}}$ J cell^?1 and $\text{38.5 × 10}{}^{\mathrm{?10}}$ J cell^?1. The time from stimulation to maximum light emission ($\text{t}{}_{\mathrm{m}}$) was found to vary with temperature logarithmically from approximately 11°C to 28°C. The corresponding regression equation was found to predict temperatures to within ±0.4°C. These results provide the basis for predicting the feasibility of an airborne laser transceiver for mapping the distribution of ocean bioluminescence. The potential exists for determining ocean surface/near surface temperature from measurements of the response pulse time parameters.     

Calibration of a TDR probe for low soil water content measurements

Time domain reflectometry (TDR) probes are increasingly used for field and laboratory estimation of soil water content. Usual calibration of TDR probes for the determination of soil water content uses two media: air for low and water for high values of dielectric permittivity, although the measured range of dielectric permittivity in soil is much smaller as compared to the range implied by the calibration media. The use of air for calibration of short TDR probes gives calibration errors due to overlapping incident and reflected pulses in the reflectogram, which result in their relative shift in time. This phenomenon, named the convolution effect, can be avoided by the application of selected calibration media. The presented approach minimizes of dielectric permittivity measurement errors by choosing the calibration media with dielectric permittivity values close to the limits of the measurement range and the possibility to use TDR probes of various lengths. The comparison of errors of TDR apparent dielectric permittivity measurement in three sandy soils, based on the probe calibrations in various media, is also presented.     

Airborne laser fluorosensor survey of the Columbia and Snake rivers: simultaneous measurements of chlorophyll,dissolved organics and optical attenuation

An airborne laser fluorosensor has been used to make concurrent, near-continuous (microscale) profiles of chlorophyll-a, dissolved organic carbon (DOC) and the beam attenuation coefficient along the Columbia and Snake rivers. Cross-reference between profiles is used to expose anomalies and explain ambiguities encountered in their interpretation. The unique potential for remote sensing of DOC concentrations is based on a strong correlation with the fluorescence of dissolved organic matter (DOM). Similarly, the reciprocal of the remotely sensed water Raman emission is shown to be a reliable predictor of the beam attenuation coefficient.

Profiles of a 734 km segment of the lower Snake and Columbia rivers obtained during peak discharge revealed a number of interesting features. In particular, the chlorophyll-a fluorescence data suggested the existence of subsurface chlorophyll-a maxima in the reservoirs formed by the eight dams of the Columbia-Snake Inland Waterway, and the absence of variability in the remotely measured DOM fluorescence data for the lower Columbia River was in close agreement with an independent DOC survey. In addition, large-amplitude long-timescale fluctuations in the chlorophyll-a fluorescence profile observed during one flight appear to be due to solar-induced photoinhibition of the in vivo chlorophyll-a fluorescence.     

抛物型内轮廓光纤检测的数值模拟

利用光路追踪程序,设计了一种可以检测抛物型内轮廓的微观轮廓曲线的反射式光强调制型光纤传感器.从模拟结果可以看出,这种传感器能很好的实现抛物型内轮廓的检测问题,具有结构简单、非接触测量、抗电磁干扰、测量速度快等优点.本文为反射式光强调制型光纤传感器用于复杂内轮廓的非接触测量提供了必要的理论分析和设计依据.     

Measurement and analysis procedures for remote identification of oil spills using a laser fluorosensor

A laser fluorosensing procedure has been developed for remotely detecting and identifying crude oils and oil based products from an airborne platform. Selected spectral and temporal characteristics of laser induced fluorescence in an unknown oil are subjected to principal component analysis followed by linear discriminant analysis, thereby facilitating an effective compression of required identification parameters and an enhanced separation of possible groups to which the unknown oil belongs. Identification relies on the availability of a trained data set, comprising principal components with large associated variance and discriminant components with large spread, of all oils likely to be involved in oil spillage at sea. Identification of the unknown oil then involves the application of a classification procedure, (such as K-nearest neighbour or SIMCA), which uses the principal components and discriminant components of the unknown oil and the trained data set.     

FINs: lattice theoretic tools for improving prediction of sugar production from populations of measurements

This paper presents novel mathematical tools developed during a study of an industrial-yield prediction problem. The set F of fuzzy interval numbers, or FINs for short, is studied in the framework of lattice theory. A FIN is defined as a mapping to a metric lattice of generalized intervals, moreover it is shown analytically that the set F of FINs is a metric lattice. A FIN can be interpreted as a convex fuzzy set, moreover a statistical interpretation is proposed here. Algorithm CALFIN is presented for constructing a FIN from a population of samples. An underlying positive valuation function implies both a metric distance and an inclusion measure function in the set F of FINs. Substantial advantages, both theoretical and practical, are shown. Several examples illustrate geometrically on the plane both the utility and the effectiveness of novel tools. It is outlined comparatively how some of the proposed tools have been employed for improving prediction of sugar production from populations of measurements for Hellenic Sugar Industry, Greece.     

A modified priority based probe algorithm for distributed deadlockdetection and resolution

A modified, priority-based probe algorithm for deadlock detection and resolution in distributed database system is presented. Various examples are used to show that the original priority-based algorithm, presented by M.K. Sinha and N. Natarajan (1985), either fails to detect deadlocks or reports deadlocks that do not exist in many situations. A modified algorithm that eliminates these problems is proposed. The algorithm has been tested through simulation and appears to be errorfree. The performance of the modified algorithm is briefly discussed     

A fibre model for push-over analysis of underdesigned reinforced concrete frames

Most of the existing reinforced concrete buildings were designed according to early seismic provisions or, sometimes, without applying any seismic provision. Some problems of strength and ductility, like insufficient shear strength, pull-out of rebars, local mechanisms, etc., could characterize their structural behaviour. The above mentioned topics lead to a number of problems in the evaluation of the seismic behaviour of reinforced concrete (RC) frames. Therefore the assessment of existing RC structures requires advanced tools. A refined model and numerical procedure for the non-linear analysis of reinforced concrete frames is presented. The current version of the model proposed is capable of describing the non-linear behaviour of underdesigned reinforced concrete frames including brittle modes of failure. Selected results of an experimental–theoretical comparison are presented to show the capabilities of this model. The results show the capacity of the model of describing both the global behaviour and the local deformation at service and ultimate state.     

A high frequency cMUT probe for ultrasound imaging of fingerprints

Fingerprint imaging using ultrasound has been investigated for several years and has shown to be a valid alternative to optical scanners. Capacitive micro-machined ultrasound transducers (cMUT) is an emerging MEMS technology that can be profitably exploited in biometric applications, like fingerprint or palm print.In this work a FEM model of a cMUT is proposed and used to design a 192-element array with a frequency band centered at 12.5 MHz. A cMUT array was manufactured by means of a proprietary fabrication process and an ultrasound probe was assembled and experimentally characterized. Comparison between simulation and experimental results has shown a quite good agreement. The cMUT probe was operated at a frequency of 12 MHz and used to produce images of fingerprints, the quality of which was quite satisfactory.     

A computerized potentiometric system for structural and functional anthropometric measurements

A prototype computerized potentiometric system was developed for structural and functional anthropometric measurements. The system uses four potentiometric units, a power supply unit, and a computer with analogue/digital (A/D) converter to measure the position of a movable stylus in three (X, Y, Z) dimensions. The system is easy to use, more accurate, and more cost effective than other existing systems. It has been found to be accurate for the intended application, faster than the manual methods available, and much less expensive than the photographic and opto-electronic systems currently available. For use in the industrial setting, a portable version of the system is envisaged in the future.     

A framework for building mobile single and multi-robot applications

The complexity of robot software systems calls for the use of a well-conceived architecture together with programming tools to support it. One common feature of robot architectures is the modular decomposition of systems into simpler and largely independent components. These components implement primitive actions and report events about their state. The robot programming framework proposed here includes a tool (RoboGraph) to program and coordinate the activity (tasks) of these middleware modules. Project developers use the same task programming IDE (RoboGraph) on two different levels. The first is to program tasks that must be executed autonomously by one robot and the second is to program tasks that can include several robots and building elements.Tasks are described using a Signal Interpreted Petri Net (SIPN) editor and stored in an xml file. A dispatcher loads these files and executes the different Petri nets as needed. A monitor that shows the state of all the running nets is very useful for debugging and tracing purposes. The whole system has been used in several applications: A tour-guide robot (GuideBot), a multi-robot surveillance project (WatchBot) and a hospital food and laundry transportation system based on mobile robots.     

Structure and mechanical properties of pincers for freshwater lobster

The mineral phases and structure of pincer for the freshwater lobster were analyzed and observed by using X-ray diffraction and field-emission scanning electronic microscope with energy dispersive spectroscopy, and the mechanical properties of pincer were determined by using nano-indenter and micro-tribometer. The results showed that the pincers contained Ca, Mg, C, O, Na, etc. elements and there were many amorphous mineral phases in the lobster pincers. There were many concave hollows and convex domes with...     

A mid-infrared optical fibre sensor for the detection of carbon monoxide exhaust emissions

An optical fibre presented is capable of monitoring the presence of carbon dioxide and carbon monoxide in the exhaust system of petrol engines. At present there exists no commercial sensor, which is capable of providing online measurements of these exhaust gases as required by European legislation. The design of this sensor using low cost and compact mid-infrared components, which make it suitable for insertion into a vehicle, is presented. Results are presented for 200 ppm step changes in concentration of carbon monoxide supplied from a laboratory controlled supply is presented.     

Remote sensing of phytoplankton pigments: A comparison of empirical and theoretical approaches

Algorithms that have been used on a routine basis for remote sensing of the phytoplankton pigment, chlorophyll- a, from ocean colour data from satellite sensors such as the CZCS (Coastal Zone Color Scanner), SeaWiFS (Sea Viewing Wide Field-of-View Sensor) and OCTS (Ocean Colour and Temperature Scanner) are all of an empirical nature. However, there exist theoretical models that allow ocean colour to be expressed as a function of the inherent optical properties of seawater, such as the absorption coefficient and the backscattering coefficient. These properties can in turn be expressed as functions of chlorophyll- a, at least for the so-called Case 1 waters in which phytoplankton may be considered to be the single, independent variable responsible for most of the variations in the marine optical properties. Here, we use such a theoretical approach to model variations in ocean colour as a function of chlorophyll- a concentration, and compare the results with some empirical models in routine use. The parameters of phytoplankton absorption necessary for the implementation of the ocean colour model are derived from our database of over 700 observations of phytoplankton absorption spectra and concurrent measurements of phytoplankton pigments by HPLC (High Performance Liquid Chromatography) techniques. Since there are reports in the literature that significant differences exist in the performance of the algorithms in polar regions compared with lower latitudes, the model is first implemented using observations made at latitudes less than 50. It is then applied to the Labrador Sea, a high-latitude environment. Our results show that there are indeed differences in the performance of the algorithm at high latitudes, and that these differences may be attributed to changes in the optical characteristics of phytoplankton that accompany changes in the taxonomic composition of their assemblages. The sensitivities of the model to assumptions made regarding absorption by coloured dissolved organic matter (or yellow substances) and backscattering by particles are examined. The importance of Raman scattering on ocean colour and its influence on the algorithms are also investigated.     

A genetic algorithm for shortest path routing problem and the sizing of populations

This paper presents a genetic algorithmic approach to the shortest path (SP) routing problem. Variable-length chromosomes (strings) and their genes (parameters) have been used for encoding the problem. The crossover operation exchanges partial chromosomes (partial routes) at positionally independent crossing sites and the mutation operation maintains the genetic diversity of the population. The proposed algorithm can cure all the infeasible chromosomes with a simple repair function. Crossover and mutation together provide a search capability that results in improved quality of solution and enhanced rate of convergence. This paper also develops a population-sizing equation that facilitates a solution with desired quality. It is based on the gambler ruin model; the equation has been further enhanced and generalized. The equation relates the size of the population, quality of solution, cardinality of the alphabet, and other parameters of the proposed algorithm. Computer simulations show that the proposed algorithm exhibits a much better quality of solution (route optimality) and a much higher rate of convergence than other algorithms. The results are relatively independent of problem types for almost all source-destination pairs. Furthermore, simulation studies emphasize the usefulness of the population-sizing equation. The equation scales to larger networks. It is felt that it can be used for determining an adequate population size in the SP routing problem.     

A self-referencing microelectrode for real time measurements of silver flux

Silver has many diverse applications, including use as a biocide for biomedical devices and potable water systems. Increased use of silver has led to a demand for technologies which can measure dissolved species in situ. In addition to the development of tools such as electrodes for measuring dissolved silver concentration, techniques are needed which can quantify spatially and temporally dynamic transport of silver. For the first time, we demonstrate the use of a self-referencing Ag⁺-selective microelectrode for non-invasively quantifying Ag⁺ flux in biomedical and environmental applications. Characterization of sensor performance included detailed analysis of microelectrode sensitivity, selectivity, response time, limit of detection, and linear range. Liquid membrane microelectrode performance was similar to modern solid state electrodes, and in self-referencing modality differential signal acquisition was sufficient for use in a wide range of applications. Self-referencing microelectrodes were used to profile concentration boundary layer transport, providing a “snapshot” of microgradients in the unstirred boundary layer. In addition, time resolved, non-invasive measurements were used to quantify Ag⁺ release rate (efflux) from two common antimicrobial biomedical devices, and Ag⁺ uptake rate (influx) to a mature Pseudomonas aeruginosa biofilm during disinfection. Use of this technique will increase our understanding of silver transport in engineered antimicrobial devices and systems. In addition, the technique may be used to better our understanding of Ag⁺ release from nanoparticles.