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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 73 (1983), S. 203-209 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Population sex ratio, size at maturity and maximum size of both sexes were determined for 22 species of mesopelagic fishes in order to document the occurence and consider the ecological significance of deviations from even sex ratio and equal-sized sexes. Specimens were collected in oblique trawls near Hawaii between August 1977 and October 1978. Eight species (mostly small myctophids) appeared to have even sex ratios and no sexual differences in size. In some other myctophids and most stomiatoids, females were either more abundant or larger than males, and consequently the biomass of mature females in the population was greater than that of mature males. Such differences mean that there must be sexual differences in ages at maturity, growth rates, or mortality rates, but adequate data on these are not available. The adaptive value of such sexual differences may be to maximize eggproducing biomass and minimize intraspecific competition in a situation where food resources are low; however, equally plausible alternate hypotheses need to be tested. Sex ratio favored males in two melamphaid species, and the relative biomass of males in the populations was greater than in comparable myctophids or stomiatoids. Although this pattern means decreased egg production per population biomass, it also means increased probability of females encountering males. This increase may be particularly important to the melamphaid species because they have no luminous organs or other sexual dimorphisms to facilitate communication.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford UK and Boston, USA : Blackwell Publishers Ltd.
    The @photogrammetric record 16 (1998), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Correction for image distortion in cameras has been an important topic for as long as users have wanted to faithfully reproduce or use observed information. Initially the main application was mapping. While this task continues today, other applications also require precise calibration of cameras, such as close range three dimensional measurement and many two dimensional measurement tasks. In the past, the cameras used were few in number and highly expensive whereas today a typical large industrial company will have many inexpensive cameras being used for highly important measurement tasks. Cameras are used more today than they ever were but the golden age of camera calibration for aerial mapping is now well in the past. This paper considers some of the key developments and attempts to put them into perspective. In particular the driving forces behind each improvement have been highlighted.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 13 (1990), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Optical triangulation is used in the human visual system and surveying tacheometers to estimate distance. This method is now used in systems with solid state sensors which enable fast measurement of distance with sufficiently high accuracy for many applications. City University has built on past experience to develop the optical triangulation technique to gather data appertaining to cross sections or profiles of structures in the range 0.2 m to 20 m radius from the measurement axis. Results obtained using three prototypes are given.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @photogrammetric record 14 (1993), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: The use of CCD cameras for digital photogrammetry has only slowly been taken up by the photogrammetric community. However, the pace of change is quickening with better understanding and cheaper equipment. Recently a decision was made to start some research into close range three dimensional digital measurement. The overall objective was to develop a low cost system for the automated measurement of small industrial objects. This shorter contribution describes the initial stages of this work.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford UK and Boston, USA : Blackwell Publishers Ltd.
    The @photogrammetric record 16 (1998), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: The principal point has long been regarded as one of the fundamental parameters in camera calibration. In the age of film based aerial and large format terrestrial cameras, the principal point could be located by a variety of techniques with a certainty of ±10 mm (Carman and Brown, 1961) and this was considered sufficient. However, aerial cameras were precision, purpose built, expensive pieces of equipment where the assembly was painstaking and the location of the principal point measured to a known tolerance. In the digital era, photogrammetrists, and many others, are using cameras which have not been specifically designed or built for photogrammetry. For these cameras there is no requirement for the manufacturers to position the lens in a pre-defined location relative to the image sensing plane or for the lens manufacturer to align the lens elements precisely. In fact, deviations from the centre of the sensor can be a considerable percentage of the extent of the sensor (up to 10 per cent for some zoom lenses (Burner, 1995)). This paper discusses the development of methods of obtaining the location of the principal point, considers the relationship between the principal point and other parameters in the functional model, and shows how the location of this point can be estimated with and without recourse to autocollimation methods.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford UK and Boston, USA : Blackwell Publishers Ltd.
    The @photogrammetric record 15 (1995), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford UK and Boston, USA : Blackwell Publishers Ltd.
    The @photogrammetric record 15 (1996), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford UK and Boston, USA : Blackwell Publishers Ltd.
    The @photogrammetric record 15 (1995), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: The accuracy of subpixel target image location is an important factor that contributes to the overall precision of three dimensional measurement when using CCD cameras. This shorter contribution reports the effect of an electrical adjustment of a frame grabber that results in a significant and systematic error in the accuracy of target image location using some target location methods.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford UK and Boston, USA : Blackwell Publishers Ltd.
    The @photogrammetric record 15 (1995), S. 0 
    ISSN: 1477-9730
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying
    Notes: The goal of automated three dimensional measurement of arbitrary objects using photogrammetric methods is a long way from being achieved, but significant progress is being made. However, automated measurement of small objects using inexpensive CCD cameras and frame grabbers is becoming increasingly common. A number of such systems have been developed both for commercial use and for academic research. It is within this latter context that a system to measure objects within a controlled environment has been developed at City University. The objective of the research is not only to produce a flexible measuring system for use in online inspection, but also to address many of the fundamental problems that hinder three dimensional measurement outside a controlled environment.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 219 (1968), S. 1149-1151 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1. TGA curve for the dehydration of manganous formate dihydrate (20.66 mg). Heating rate 1 min?1. Kinetic parameters are often derived1?3,6,11 from TGA data, for reactions of type (1), by assuming that the rate may be expressed in the form % -*〈?-?〉? (2) where a is the fractional ...
    Type of Medium: Electronic Resource
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