Exploring Hybrid Indoor Positioning Systems

Ubiquitous applications collect contextual information, process it, and then use this derived data to deliver valuable services. Location is one these contexts, and has been significant in providing navigation and guidance services for GPS devices. However, GPS is designed for outdoor use and is not precise enough, in terms of location accuracy for indoor applications. There are many indoor location systems that rely on a single technology, but these systems are either inaccurate in uncontrolled environments or require the installation of a dedicated infrastructure. This has led to the investigation of hybrid systems. This thesis examines the creation of a hybrid indoor positioning system combining different tech­ nologies and techniques; Wi-Fi access points and their associated signal strength, image analysis using machine learning to create location specific scene classifiers, and an altimeter sensor to determine the user\u27s current floor. This system is meant to provide indoor positioning data to location-aware applications

Evolution of the Female Labour Force Participation Rate in Canada, 1976-1994: a Cohort Analysis

The participation rate of women aged 25-64 rose greatly in the 1970s and 1980s, but has stagnated in the 1990s. In principle, this development could reflect either the poor growth performance of the economy this decade or the completion of the integration of women into the labour force. In the fourth article of this symposium, Paul Beaudry and Thomas Lemieux use a cohort analysis to shed light on the explanation of this stagnation in female labour force participation. Using data from the Survey of Consumer Finances for the 1976-94 period, the authors track the participation rates over time of representative groups of women who entered the labour force at different points in time. They decompose a cohort’s participation rate into three effects: a macroeconomic effect common across cohorts linked to factors such as recessions and employment insurance generosity; an age or life-cycle effect; and a cohort-specific effect which shows the differences between cohorts for a given age and macroeconomic effect. The authors find that the cohort effects are likely the dominant factor in explaining the recent stagnation of female participation, just as it explained the large increases in the 1970s and 1980s. The recession of the early 1990s, which according to the authors reduced the female participation rate by 1 percentage point, merely amplified the stagnation phenomenon. As the cohort effects stabilize with the narrowing of the gap between male and female participation rates, the stagnation would have occurred, albeit later in the 1990s, even if more favourable macroeconomic conditions had prevailed. The authors conclude that there is still room for a 2-3 percentage point increase in the participation rate of women 25-64, but the magnitude of the increases of the 1970s and 1980s is not possible as the cohort effects that prevailed then no longer exist. The authors stress that their results are dependent on the amount of flexibility used to capture the cohort effect so that the age profile and its slope can trace both the rise and the flattening of the participation rate by age. They point out that over time participation behaviour of women 25-64 is converging toward that of men, namely, high and flat participation profiles to at least age 55. They also note that the much smaller increase in the female participation rate in the United States in the 1990s relative to the 1970s and 1980s despite the robust U.S. labour market supports their findings as the cohort effects were also levelling out south of the border.Canada, Labour Force Participation, Labor Force Participation, Participation Rate, Labour Force Participation Rate, Labor Force Participation Rate, Age Structure, Age, Sex, Gender, Aging, Ageing, Women

Noncanonical spike-related BOLD responses in focal epilepsy

Till now, most studies of the Blood Oxygen Level-Dependent (BOLD) response to interictal epileptic discharges (IED) have assumed that its time course matches closely to that of brief physiological stimuli, commonly called the canonical event-related haemodynamic response function (canonical HRF). Analyses based on that assumption have produced significant response patterns that are generally concordant with prior electroclinical data. In this work, we used a more flexible model of the event-related response, a Fourier basis set, to investigate the presence of other responses in relation to individual IED in 30 experiments in patients with focal epilepsy. We found significant responses that had a noncanonical time course in 37% of cases, compared with 40% for the conventional, canonical HRF-based approach. In two cases, the Fourier analysis suggested activations where the conventional model did not. The noncanonical activations were almost always remote from the presumed generator of epileptiform activity. In the majority of cases with noncanonical responses, the noncanonical responses in single-voxel clusters were suggestive of artifacts. We did not find evidence for IED-related noncanonical HRFs arising from areas of pathology, suggesting that the BOLD response to IED is primarily canonical. Noncanonical responses may represent a number of phenomena, including artefacts and propagated epileptiform activity

Human urinary mutagenicity after wood smoke exposure during traditional temazcal use.

In Central America, the traditional temazcales or wood-fired steam baths, commonly used by many Native American populations, are often heated by wood fires with little ventilation, and this use results in high wood smoke exposure. Urinary mutagenicity has been previously employed as a non-invasive biomarker of human exposure to combustion emissions. This study examined the urinary mutagenicity in 19 indigenous Mayan families from the highlands of Guatemala who regularly use temazcales (N = 32), as well as control (unexposed) individuals from the same population (N = 9). Urine samples collected before and after temazcal exposure were enzymatically deconjugated and extracted using solid-phase extraction. The creatinine-adjusted mutagenic potency of urine extracts was assessed using the plate-incorporation version of the Salmonella mutagenicity assay with strain YG1041 in the presence of exogenous metabolic activation. The post-exposure mutagenic potency of urine extracts were, on average, 1.7-fold higher than pre-exposure samples (P < 0.005) and also significantly more mutagenic than the control samples (P < 0.05). Exhaled carbon monoxide (CO) was ~10 times higher following temazcal use (P < 0.0001), and both CO level and time spent in temazcal were positively associated with urinary mutagenic potency (i.e. P < 0.0001 and P = 0.01, respectively). Thus, the wood smoke exposure associated with temazcal use contributes to increased excretion of conjugated mutagenic metabolites. Moreover, urinary mutagenic potency is correlated with other metrics of exposure (i.e. exhaled CO, duration of exposure). Since urinary mutagenicity is a biomarker associated with genetic damage, temazcal use may therefore be expected to contribute to an increased risk of DNA damage and mutation, effects associated with the initiation of cancer

Materials and Coatings Damage Resulting from Environmental Degradation Aboard Naval Ships

Maintenance and preservation of seawater and fuel, ballast tanks and voids resulting from the environmental degradation of coatings present a unique and costly problem for the United States Naval Fleet. Present methods of inspection require human entry into the tanks only after a series of measurements have been taken to ensure safety. With the advent of remotely operated vehicles and cameras having a high level of accuracy and functionality, it has now become economically feasible to employ these instruments for the inspection of tanks and voids of the United States Naval Fleet. This paper presents two unique remotely operated inspections systems, which allow for unmanned inspection of tanks and voids along with quantitative results of the damaged coating areas

Design and construction of a rotary kiln simulator for use in studying the incineration of hazardous waste

Journal ArticleRotary kilns have been used extensively in the cement industry to calcine limestone. In the past few years, the technology has been viewed as a possible option for the incineration of hazardous waste materials, especially for the disposal of solid wastes and the cleanup of contaminated soils and transformers.1 The technology is promising for incineration of hazardous waste for several reasons. First, it is flexible,2 i.e., many different types of solids and liquids can be fed into a single facility. Second, in some cases, incineration greatly reduces the volume of solid waste streams. Finally, there are many existing facilities that could be retrofitted for use in hazardous waste incineration. The kiln is used to drive the hazardous compounds into the gas phase, and an afterburner is used to destroy the gaseous compounds by exposing them to the required time/temperature history. Incineration success is measured by the destruction and removal efficiency (DRE), for each toxic component, which is defined as DRE = (Massin - Massou! )/Massin X 100% . (1) Generally, a DRE of at least 99.99% is required by the EPA. Facilities have been determined to be successful as long as these criteria are been satisfied. Whether a smaller or lower temperature facility could have produced the same results is generally not known, because the tests are often done on already existing facilities. The ambiguous nature of DRE also prevents success from being accurately measured; 99.99% DRE of a component with a high initial concentration in a waste is considerably easier to measure accurately than 99.99% DRE of a compound initially present in small amounts. Because of the rising costs and legal liabilities associated with hazardous waste disposal, there is now considerable interest in optimizing the disposal options. In order to mitigate the costs involved in hazardous waste incineration, it is necessary to define the temporal and thermal requirement for a particular application by testing the specific waste stream to establish its suitability for rotary kiln incineration. Each waste stream has its own particular properties and thus its own particular problems associated with incineration.3 Small-scale testing is desirable to determine the feasibility of incinerating a particular waste stream in a rotary kiln. Such testing can aid in the design and sizing of the kiln, in defining the optimum operating conditions, and determining whether or not rotary kiln incineration is appropriate for that particular waste stream

What Is Happening in the Youth Labour Market in Canada?

This paper analyzes the evolution of the labour market participation rate of men and women age 15 to 24 from 1976 to 1998. The0501n question being asked is why youth participation rates fell precipitously during the 1990s? We look at two dimensions of this decline: changes in the participation rate of youth who are not attending school (non-student participation rate) and changes in the employment rate of students. We find that the decline in the non-student participation rate is a consequence of two factors: (1) the overall bad state of the labour market in Canada during the 1990s, and (2) the large increase in school enrollment rates induced by factors other than the state of the labour market. One important finding is that demographic changes (baby boom vs baby bust) is a key explanation behind the steep increase in enrollment rates during the 1980s and 1990s. The only component of youth participation rates which seems to be a problem specific to the 1990s is the sharp drop in employment rates of students age 15 to 19. Cette étude vise à analyser l'évolution du taux de participation des jeunes Canadiens âgés de 15 à 24 ans au cours de la période allant de 1976 à 1998. Plus précisément, nous cherchons à comprendre pourquoi le taux de participation des jeunes a chuté au cours des années 90. Pour ce faire, nous examinons les changements dans le taux de participation des jeunes qui ne fréquentent pas l'école ainsi que les changements dans le taux d'emploi des étudiants. Les résultats indiquent que la baisse du taux de participation des jeunes découle de deux facteurs : (1) les mauvaises conditions globales du marché du travail au Canada durant les années 90, et (2) l'augmentation substantielle de la fréquentation scolaire causée par des facteurs autres que l'effet induit par les conditions du marché du travail. Un résultat important est que les changements démographiques constituent un facteur-clé pouvant expliquer l'accroissement important des taux de fréquentation scolaire au cours des années 80 et 90. La seule composante pouvant expliquer la chute des taux de participation qui soit spécifique aux années 90 est la forte baisse des taux d'emploi des étudiants âgés de 15 à 19 ans.Education, labour market, Éducation, marché du travail