5,335 research outputs found
Shifting Skill Demand and the Canada-US Unemployment Gap: Evidence from Prime-Age Men
This paper considers the possible role of shifts in labour demand away from unskilled workers, combined with an institutionally- generated greater labour supply elasticity in Canada, in explaining the apparent secular increase in Canadian male unemployment, and in explaining the emergence of the Canada-U.S. unemployment rate gap in the 1980's. Using comparable data on annual weeks worked and unemployed in both countries, we identify four main facts which are consistent with such this explanation: Both Canada and the US experienced wage polarization over this period, with substantial real wage declines for unskilled men; annual weeks worked fell disproportionately among unskilled workers in both countries; responses of weeks worked to wage declines were more elastic in Canada; and aggregate movements out of employment over this period corresponded closely to movements into unemployment in Canada. Interestingly, however, unskilled U.S. men were more likely than Canadians to leave the labour force as their employment fell, adding further to the Canada-U.S. unemployment gap. As well, some fairly substantial decreases in weeks worked are observed quite high up in the Canadian wage distribution, where wages did not fall appreciably. The latter changes cannot easily be explained by a shifts in labour demand alone.
SAM 2 measurements of the polar stratospheric aerosol. Volume 9: October 1982 - April 1983
The Stratospheric Aerosol Measurement (SAM) II sensor aboard Nimbus 7 is providing 1.0 micron extinction measurements of Antarctic and Arctic stratospheric aerosols with a vertical resolution of 1 km. Representative examples and weekly averages including corresponding temperature profiles provided by NOAA for the time and place of each SAM II measurement are presented. Contours of aerosol extinction as a function of altitude and longitude or time are plotted, and aerosol optical depths are calculated for each week. Typical values of aerosol extinction and stratospheric optical depth in the Arctic are unusually large due to the presence of material from the El Chichon volcano eruption in the Spring of 1982. For example, the optical depth peaked at 0.068, more than 50 times background values. Typical values of aerosol extinction and stratospheric optical depth in the Antarctic varied considerably during this period due to the transport and arrival of the material from the El Chichon eruption. For example, the stratospheric optical depth varied from 0.002 in October 1982, to 0.021 in January 1983. Polar stratospheric clouds were observed during the Arctic winter, as expected. A representative sample is provided of the ninth 6-month period of data to be used in atmospheric and climatic studies
Doing evolution in economic geography
Evolutionary approaches in economic geography face questions about the relationships between their concepts, theories, methods, politics, and policy implications. Amidst the growing but unsettled consensus that evolutionary approaches should employ plural methodologies, the aims here are, first, to identify some of the difficult issues confronting those working with different frameworks. The concerns comprise specifying and connecting research objects, subjects, and levels; handling agency and context; engaging and integrating the quantitative and the qualitative; comparing cases; and, considering politics, policy, and praxis. Second, the purpose is to articulate a distinctive geographical political economy approach, methods, and illustrative examples in addressing these issues. Bringing different views of evolution in economic geography into dialogue and disagreement renders methodological pluralism a means toward improved understanding and explanation rather than an end in itself. Confronting such thorny matters needs to be embedded in our research practices and supported by greater openness; more and better substantiation of our conceptual, theoretical, and empirical claims; enhanced critical reflection; and deeper engagement with politics, policy, and praxis
Censorship and the Supreme Court: Re Nova Scotia Board of Censors et al. v. McNeil
On January 8, 1974, the Nova Scotia Amusements Regulation Board banned the showing of the film Last Tango in Paris. Gerard McNeil, the editor of a Dartmouth newspaper, decided to challenge the powers of the Board to make such prohibitions. He first appealed to the Lieutenant-Governor in Council, as required by section 3(4) of the Theatres and Amusements Act\u27 but he was not recognized by that body as having the right to appeal. He then requested the Attorney-General to refer the constitutionality of the Act to the Appeal Division of the Supreme Court of Nova Scotia, but to no avail. Early in 1974 Mr. McNeil applied to the Trial Division of the Nova Scotia Supreme Court for a declaration that the Board was exercising unconstitutional powers to censor or ban films.2 In the event that preliminary questions were resolved as to the proper parties to the action, Hart J. granted standing to Mr. McNeil and allowed the Court to set a date for hearing upon the constitutional merits. Subsequently, an appeal to the Supreme Court of Canada by the Censor Board contesting the applicant\u27s standing was dismissed on May 20, 1975
Spectral radiometry and tropospheric aerosols: Report of panel
The term aerosols, as used here, refers to the haze, smoke, and dust that appear in the troposphere. The term does not refer to the hydrometeors in cumulus and stratus clouds but does include the sulfuric acid-water droplets which are assumed to predominate in the stratospheric aerosol layer. The aerosol properties that were measured from satellites and those which can be made in the near term (up to 1992) will be reviewed. The capabilities that will exist in the years 1992 to 2000, with implementation of EOS, are then discussed. Finally, a few words will be said concerning the potential for aerosol measurements for the decade after 2000
A low cost cell calibration technique and its PC based control software
In this study, a technique will be presented to measure the absolute position of a robot and any other strategic positions within the workcell, and also its specially built control software.
One of the most important factors affecting the absolute or world accuracy of robots is the variation in arm geometry from a perfect kinematics form. Since arm position is essentially controlled by means of joint angles, Cartesian co-ordinates of the tool centre point are derived from the forward kinematics transform equations assuming a perfect kinematics form. Any deviation from this perfect case will result in world positional errors and hence, for effective off-line programming it is important to calibrate the real robot hardware against the virtual model used by the robot simulation computer systems.
This paper will report on work carried out in developing such low cost calibration technique, its PC Based control software and performance monitoring systems
Automation of beam straightness measurement
This work deals with the development of an image processing methodology to be employed in an inspection machine for measurement of straightness of moving steel beams. The method consists of developing specific software to perform three main tasks: reading the position of the beam at several locations; correlating the data monitored by the cameras; and reporting the quality of the beam straightness. Computer vision technology as a non contact measuring system is used by the inspection machine. From the production process the beams roll onto a conveyor therefore several video cameras are needed to log information about the lateral position and also the height of the steel beams. The number of cameras and the distance between them can be defined by the user. The technique is developed in such a way that if one camera fails or is switched off the measuring system is not affected as long as the system has a minimum of three cameras viewing acceptable points. The system outputs is the deviations from a perfectly straight beam; compensating factors for lateral or angular movements in the horizontal measuring plane of the beam and the beam profile. The output is displayed on a computer screen, and is based on both linear and least squares curve fitting routines
Cell calibration and robot tracking
When considering off-line programming of Industrial robots, it is important that the simulated model of the robot and its environment is calibrated against the real hardware.
It is well known that industrial robots have relatively good position repeatability characteristics but suffer from a lack of precision in terms of absolute accuracy. When programmed on-line, this is not apparent since the programmer intuitively moves the robot to location points which are relative to the workpiece and other elements within the cell.
However, when considering off-line programming using simulation software to represent the robot and its environment, the absolute accuracy of the system becomes a critical issue. The effectiveness of off-line programming is only apparent if there is a true correspondence between the “virtual” simulation system and the “real” hardware system.
In order to provide cell calibration, it is important to be able to measure the absolute position of the robot and other strategic locations within the cell. This paper presents details of a measuring system for recording tool point absolute positions and path trajectories. It is intended that this data is then used to improve the correlation between the simulated and the real kinematics of the robot cell
A methodology for design of lightweight robotic arm links in harsh environments
A methodology for the creation of functionally graded material (FGM) parts in harsh environments has been developed. It uses a two-stage optimisation approach that focusses first on the task-dependent material choice and then on the topological optimisation (TO) of the part. Constraints are in place to ensure the part can be manufactured, including the extent/smoothness of material blending and the minimum feature size and layer thickness. Thought is also put into space-specific concerns, such as radiation and cyclic thermal heating. The methodology assumes an initial design solution has already been generated, and covers from the beginning of the CAD phase to the end of the computational testing phase. Design constraints are created with additive manufacture (AM) in mind, and suggestions are made for material mixing processes for FGM, material layout strategies and manufacturability, including scanning strategies and surface finish
The design of a robotic arm link using functionally graded materials : a case study
The development and design of a functionally-graded material (FGM) robotic arm for supporting and manipulating a vision system is discussed in this paper. The aim is to understand if using FGMs effectively reduce mass compared to single material parts. The evolution of ideas using topological optimisation (TO) and FGMs towards the design are shown and reviewed. The final design uses TO, and as such needs to be manufactured using additive manufacture (AM). Constraints have been put in place to ensure physical manufacturability is possible. The final design reduces the mass compared to the original arm by 61.4%
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