MAGNETIC FIELD SENSOR UTILIZING MAGNETO IMPEDANCE IN THIN FILM MULTI-LAYERS

Since the discovery of the Magneto Impedance (MI) effect in 1994 there has been a global increase in the research devoted to understanding the effect. In certain magnetic materials, the impedance change, often referred to as the MI ratio, is in the range of 50 to 100% for an excitation current in the MHz frequency range for external magnetic fields of a few Oe. The use of thin film multilayer structures allows the increase of sensitivity and the reduction of size for MI effect to be integrated with micro magnetic sensor technologies. In the present work, we explain the origins of the MI effect and its versatile nature for the development of sub nano Tesla magnetic field sensors. The matrix like nature of the MI effect allows a variety of MI characteristics to be implemented in a thin film, which allows the structure to be tailored for maximum sensitivity in the chosen field sensing application. In the case of a simple transverse magnetic anisotropy, the diagonal components of the MI matrix are symmetric and the off diagonal components are anti-symmetric with respect to the dc longitudinal field. The asymmetry in the MI behaviour can be related to either a certain asymmetric arrangement of the dc magnetization (crossed an isotropy), or a contribution to the measured voltage due to the ac cross-magnetization process, which is represented as an off-diagonal component. These asymmetrical characteristics are useful in producing linear bi-directional field sensors without DC biasing. In attempt to find optimal film systems with respect to relative impedance change, sensitivity, linearity, operational frequency range, and dimensions, thin film multi-layers, consisting of a magnetic / conductor / magnetic material configuration were fabricated. Variations in magnetic compositions, geometries, structures and magnetic configurations (transverse, longitudinal or cross anisotropy) and additional insulations layers were produced. Planar coil thin film multi-layers were constructed to utilize the more magnetic complex asymmetric characteristics of the MI effect. An experimental configuration was developed in order to measure all components of the MI matrix within the thin films and standardise their sensitivity using the MI ratio. Two sub nano Tesla magnetic field sensors were developed during the course of this work based on the fabricated thin films. The first sensor concentrates on utilizing two asymmetrical Magneto Impedance (AMI) elements combined differentially. The sensor is driven by a sinusoidal current of 90 MHz biased with a dc bias current. For AMI film element of 5mm long, 40µm wide and having anisotropy angle of 45° the field detection resolution is in the magnitude of 1µ Oe for both ac and dc for fields of ~ 20e magnitude. The maximum response speed is in the order of 1MHz. The use of MI to the measurement low frequency fields such as bio-medical signals drove the design of the second sensor. Extensive research was undertaken to improve the phase noise of the oscillator and sensitivity of the detection mechanism using novel RF techniques to improve the sensitivity at high frequencies, and secondly a method to improve the low frequency sensitivity by AC biasing the MI element with a magnetic field. A thin film multilayer MI sensor was produced based on the measurement of the modulation of the incident reflected power due to an external AC magnetic field. Direct field measurement performance at 1kHz produced a resolution of 3.73 x 10-7 Oe. AC biased performance at 5kHz of a 20Hz field was a resolution of 5.27 x 10-6 Oe, and at 10Hz of 9.33 x 10-6 Oe. With continued improvement of the electronic components utilized in this novel method of Magneto Impedance sensor presented in this work, the possibility of measuring bio magnetic signals of the human body at room temperature becomes a distinct reality

ITS Ada: an intelligent tutoring system for the Ada programming language.

Most tutoring systems are machine dependent. In this thesis we present an intelligent tutoring system, ITS Ada, that exploits the designed portability of Ada. ITS Ada possesses full knowledge of Ada as defined in the official language reference manual and consists of four major components. The instructional module is a series of screens presented in an order determined by a topic network that covers the complete set of concepts in the Reference Manual for the Ada Programming Language. Superordinate concepts will be presented only after the prerequisite concepts have been mastered. There are exercise problems associated with each topic. The problems are presented by the diagnostic module in either an expository or interrogatory format, based on the student's mastery level for that concept, as determined by the student module. Solutions to the given problems are checked by parsing the student's response into a meaning list and comparing the results with solutions in the expert module. ITS Ada has been tested on three platforms: PC/InterAda, Sun SparcStation/Verdix Ada, and Apple Macintosh/Meridian Ada. We believe it can be run on any system with a validated Ada compiler.http://archive.org/details/itsadaintelligen00deloLieutenant , United States NavyApproved for public release; distribution is unlimited

Gas-to-Dust mass ratios in local galaxies over a 2 dex metallicity range

This paper analyses the behaviour of the gas-to-dust mass ratio (G/D) of local Universe galaxies over a large metallicity range. We combine three samples: the Dwarf Galaxy Survey, the KINGFISH survey and a subsample from Galametz et al. (2011) totalling 126 galaxies, covering a 2 dex metallicity range, with 30% of the sample with 12+log(O/H) < 8.0. The dust masses are homogeneously determined with a semi-empirical dust model, including submm constraints. The atomic and molecular gas masses are compiled from the literature. Two XCO are used to estimate molecular gas masses: the Galactic XCO, and a XCO depending on the metallicity (as Z^{-2}). Correlations with morphological types, stellar masses, star formation rates and specific star formation rates are discussed. The trend between G/D and metallicity is empirically modelled using power-laws (slope of -1 and free) and a broken power-law. We compare the evolution of the G/D with predictions from chemical evolution models. We find that out of the five tested galactic parameters, metallicity is the galactic property driving the observed G/D. The G/D versus metallicity relation cannot be represented by a power-law with a slope of -1 over the whole metallicity range. The observed trend is steeper for metallicities lower than ~ 8.0. A large scatter is observed in the G/D for a given metallicity, with a dispersion of 0.37 dex in metallicity bins of ~0.1 dex. The broken power-law reproduces best the observed G/D and provides estimates of the G/D that are accurate to a factor of 1.6. The good agreement of the G/D and its scatter with the three tested chemical evolution models shows that the scatter is intrinsic to galactic properties, reflecting the different star formation histories, dust destruction efficiencies, dust grain size distributions and chemical compositions across the sample. (abriged)Comment: 23 pages, 12 figures, accepted in Astronomy & Astrophysic

Encode a letter and get its location for free? Assessing incidental binding of verbal and spatial features

Previous studies have demonstrated that when presented with a display of spatially arranged letters, participants seem to remember the letters’ locations when letters are the focus of a recognition test, but do not remember letters’ identity when locations are tested. This strong binding asymmetry suggests that encoding location may be obligatory when remembering letters, which requires explanation within theories of working memory. We report two studies in which participants focused either on remembering letters or locations for a short interval. At test, positive probes were either intact letter–location combinations or recombinations of an observed letter and another previously occupied location. Incidental binding is observed when intact probes are recognized more accurately or faster than recombined probes. Here, however, we observed no evidence of incidental binding of location to letter in either experiment, neither under conditions where participants focused on one feature exclusively for a block, nor where the to-be-remembered feature was revealed prior to encoding with a changing pre-cue, nor where the to-be-remembered feature was retro-cued and therefore unknown during encoding. Our results call into question the robustness of a strong, consistent binding asymmetry. They suggest that while incidental location-to-letter binding may sometimes occur, it is not obligatory

Developing an acoustic-phonetic characterization of dysarthric speech in French

- ISBN: 2-9517408-6-7 - Domaines: Phonetic Databases, Phonology, Person IdentificationInternational audienceThis paper presents the rationale, objectives and advances of an on-going project (the DesPho-APaDy project funded by the French National Agency of Research) which aims to provide a systematic and quantified description of French dysarthric speech, over a large population of patients and three dysarthria types (related to the parkinson's disease, the Amyotrophic Lateral Sclerosis disease, and a pure cerebellar alteration). The two French corpora of dysarthric patients, from which the speech data have been selected for analysis purposes, are firstly described. Secondly, this paper discusses and outlines the requirement of a structured and organized computerized platform in order to store, organize and make accessible (for selected and protected usage) dysarthric speech corpora and associated patients' clinical information (mostly disseminated in different locations: labs, hospitals, ...). The design of both a computer database and a multi-field query interface is proposed for the clinical context. Finally, advances of the project related to the selection of the population used for the dysarthria analysis, the preprocessing of the speech files, their orthographic transcription and their automatic alignment are also presented

Using Kinect sensor in observational methods for assessing postures at work

This paper examines the potential use of Kinect range sensor in observational methods for assessing postural loads. Range sensors can detect the position of the joints at high sampling rates without attaching sensors or markers directly to the subject under study. First, a computerized OWAS ergonomic assessment system was implemented to permit the data acquisition from Kinect and data processing in order to identify the risk level of each recorded postures. Output data were compared with the results provided by human observers, and were used to determine the influence of the sensor view angle relative to the worker. The tests show high inter-method agreement in the classification of risk categories (Proportion agreement index = 0.89 k = 0.83) when the tracked subject is facing the sensor. The camera’s point of view relative to the position of the tracked subject significantly affects the correct classification of the postures. Although the results are promising, some aspects involved in the use of low-cost range sensors should be further studied for their use in real environmentsDiego-Mas, JA.; Alcaide Marzal, J. (2014). Using Kinect sensor in observational methods for assessing postures at work. Applied Ergonomics. 1-10. doi:10.1016/j.apergo.2013.12.001S11

Change in Blood Pressure Variability Among Treated Elderly Hypertensive Patients and Its Association With Mortality

Background: Information is scarce regarding effects of antihypertensive medication on blood pressure variability (BPV) and associated clinical outcomes. We examined whether antihypertensive treatment changes BPV over time and whether such change (decline or increase) has any association with long-term mortality in an elderly hypertensive population. Methods and Results: We used data from a subset of participants in the Second Australian National Blood Pressure study (n=496) aged ≥65 years who had 24-hour ambulatory blood pressure recordings at study entry (baseline) and then after a median of 2 years while on treatment (follow-up). Weighted day-night systolic BPV was calculated for both baseline and follow-up as a weighted mean of daytime and nighttime blood pressure standard deviations. The annual rate of change in BPV over time was calculated from these BPV estimates. Furthermore, we classified both BPV estimates as high and low based on the baseline median BPV value and then classified BPV changes into stable: low BPV, stable: high BPV, decline: high to low, and increase: low to high. We observed an annual decline (mean±SD: −0.37±1.95; 95% CI, −0.54 to −0.19; P<0.001) in weighted day-night systolic BPV between baseline and follow-up. Having constant stable: high BPV was associated with an increase in all-cause mortality (hazard ratio: 3.03; 95% CI, 1.67–5.52) and cardiovascular mortality (hazard ratio: 3.70; 95% CI, 1.62–8.47) in relation to the stable: low BPV group over a median 8.6 years after the follow-up ambulatory blood pressure monitoring. Similarly, higher risk was observed in the decline: high to low group. Conclusions: Our results demonstrate that in elderly hypertensive patients, average BPV declined over 2 years of follow-up after initiation of antihypertensive therapy, and having higher BPV (regardless of any change) was associated with increased long-term mortality

Medea Through the Eyes of Her Audience: Judgments on the Child-Killer From Antiquity Through Modernity

The goal of this paper is to examine the traditions of mythic character of Medea, infamous for killing her children in the attempt to punish her unfaithful husband. I will examine the works of Euripides, Seneca, Geoffrey Chaucer and Christa Wolf in order to analyze the changing attitudes towards the themes of infanticide, barbarism, magical qualities and heroism as they relate to Medea. This study will include a look at the internal audience--the characters--and external audience--the public--to see how they responded to the different elements of the work at the time it was created. Chapter One examines Euripides\u27 play Medea, written in 431 BC in Athens, and the creation of Medea as deliberate murderer of her children. Chapter Two deals with Seneca\u27s Medea and his reaction to the writing of Euripides in 1st century A.D. Rome. In Chapter Three, Chaucer\u27s The Legend of Good Women, written during the 14th century in England, takes away much of the individuality and perseverance that we see in Euripides\u27 and Seneca\u27s plays. In my final chapter, I explore Wolf\u27s Medea, which was written in 20th century Germany, and which combines elements of many of the previous versions of Medea. Even though the material presented by these authors spans well over 2,000 years, they are all tied together by the character Medea and in the way that the texts interact with one another. The authors of each of these versions of Medea are aware of what previous authors did with the story before them. In their own versions, authors incorporate pieces of previous versions as a reaction or a conscious way of changing the story. As a result, the Medea story has the same character, similar events, but her story continues to shock audiences in new and unexpected ways