Measurement units have historically been defined as quantities (i.e. specific properties) of objects, such as the mass of a particular piece of metal or the length of a particular rod. While the current International System of Units (SI) Brochure endorses this position, the draft 9th SI Brochure proposes to change it, and instead define measurement units as values of quantities. The reason for this proposed change is not provided, but it does not seem plausible that it is related to the redefinition of the SI units in terms of fundamental constants of nature: the very concept of what a unit is does not depend on the concrete way any given unit is defined. This paper is intended to open a discussion of whether measurement units should be defined as quantities or as quantity values, and provides our rationale for maintaining the definition of units as quantities.

The Guide to the Expression of Uncertainty in Measurement (GUM) provided for the first time an international consensus on how to approach the widespread difficulties associated with conveying information about how reliable the value resulting from a measurement is thought to be.This paper examines the evolution in thinking and its impact on the terminology that accompanied the development of the GUM. Particular emphasis is put on the very clear distinction in the GUM between measurement uncertainty and measurement error, and on the reasons that even though 'true value' and 'error' are considered in the GUM to be 'unknowable' and, sometimes by implication, of little (or even no) use in measurement analysis, they remain as key concepts, especially when considering the objective of measurement.While probability theory in measurement analysis from a frequentist perspective was in widespread use prior to the publication of the GUM, a key underpinning principle of the GUM was to instead consider probability as a 'degree of belief.' The terminological changes necessary to make this transition are also covered.Even twenty years after the publication of the GUM, the scientific and metrology literatures sometimes contain uncertainty analyses, or discussions of measurement uncertainty, that are not terminologically consistent with the GUM, leading to the inability of readers to fully understand what has been done and what is intended in the associated measurements. This paper concludes with a discussion of the importance of using proper methodology and terminology for reporting measurement results.

‘Measurement error’2 has historically been defined in the metrology community as a difference of ‘values,’ usually as a difference between a ‘measured value’ and a ‘reference value.’ The reference ...

Different approaches to the philosophy and description of measurement have evolved over time, and they are still evolving. There is not always a clear demarcation between approaches, but rather a blending of concepts and terminologies from one approach to another. This sometimes causes confusion when trying to ascertain the objective of measurement in the different approaches, since the same term may be used to describe different concepts in the different approaches. Important examples include the terms “value,” “true value,” “error,” “probability” and “uncertainty.” Constructing a single vocabulary of metrology that is able to unambiguously encompass and harmonize all of the approaches is therefore difficult, if not impossible. This paper examines the evolution of common philosophies and ways of describing measurement. Some of the differences between these approaches are highlighted, which provides a rationale for the entries and structure of the August 2006 draft of the 3rd Edition of the International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (VIM3) [1].

The unreliability of photosensor-based lighting controls continues to be a significant market barrier that prevents widespread acceptance of daylight dimming controls in commercial buildings. Energy savings from the use of daylighting in commercial buildings is best realized through the installation of reliable photoelectric lighting controls that dim electric lights when sufficient daylight is available to provide adequate background and/or task illumination. In prior work, the authors discussed the limitations of current simulation approaches and presented a robust method to simulate the performance of photosensor-based controls using an enhanced version of the radiance lighting simulation package. The method is based on the concept of multiplying two fisheye images: one generated from the angular sensitivity of the photosensor and the other from a 180 or 360° fisheye image of the space as “seen” by the photosensor. This paper includes a description of the method, its validation and possible applications for designing, placing, calibrating and commissioning photosensor-based lighting controls.

Magnetic scanning high current implanters pose a unique challenge to achieving the wafer doping uniformity that is typical of serial implant, lower current machines. Precise control of the beam centroid location over the spinning disk is essential to the achievement of good wafer uniformity, as evidenced by machine performance and computer simulation. A technique has been developed on the Varian/Extrion 120-10 to obtain this control as well as compensate for any machine aberrations to improve the dose uniformity over a wide range of implant conditions. This technique uses the machine computer system and the actual implanted wafer resistivity data to determine an improved functional dependence of the scan rate with beam location. Subsequent implants are then run with this compensated scan rate information. Successful use of this technique at the 1% level will be demonstrated for 100, 125 and 150 mm wafers.

The Extrion 160-10 ion implanter has been developed to meet the needs of users requiring high dose implants at high throughput over a wide dynamic range of species and energies. A unique three stage acceleration system provides the capability of high transmission transport over the full energy range of 40 to 160 keV. As+ output of 10 mA and B+ output of 5 mA are available over the full range of operation. Post acceleration analysis is utilized to remove molecular breakup contaminants commonly produced in acceleration systems.