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  • 1
    Electronic Resource
    Electronic Resource
    Sensitivity analysis in Gauss-Markov models (1996)
    Springer
    Journal of geodesy 70 (1996), S. 480-488 
    Details
    ISSN: 1432-1394
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract The estimated parameters from a Gauss-Markov model have varying sensitivity to the individual observations included in the model. Similarly, the redundancy contribution (number) of any observation is associated differently to all the other observations in the model. Evaluation of the sensitivity of parameters to observations, and the sensitivity of the redundancy contribution of one observation to the others are useful to gain more insight into Gauss-Markov models. Such analysis has found practical applications in survey network design and in multiple outlier detections. This paper presents some quantitative sensitivity measures for general Gauss-Markov models. The application of the concept in surveying network design is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00863620
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  • 2
    Electronic Resource
    Electronic Resource
    Multiple outlier detection by evaluating redundancy contributions of observations (1996)
    Springer
    Journal of geodesy 70 (1996), S. 489-498 
    Details
    ISSN: 1432-1394
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract When applying single outlier detection techniques, such as the Tau (τ) test, to examine the residuals of observations for outliers, the number of detected observations in any iteration of adjustment is most often more numerous than the actual number of true outliers. A new technique is proposed which estimates the number of outliers in a network by evaluating the redundancy contributions of the detected observations. In this way, a number of potential outliers can be identified and eliminated in each iteration of an adjustment. This leads to higher efficiency in data snooping of geodetic networks. The technique is illustrated with some numerical examples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00863621
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  • 3
    Electronic Resource
    Electronic Resource
    Multiple outlier detection by evaluating redundancy contributions of observations (1996)
    Springer
    Journal of geodesy 70 (1996), S. 489-498 
    Details
    ISSN: 1432-1394
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract. When applying single outlier detection techniques, such as the Tau (τ) test, to examine the residuals of observations for outliers, the number of detected observations in any iteration of adjustment is most often more numerous than the actual number of true outliers. A new technique is proposed which estimates the number of outliers in a network by evaluating the redundancy contributions of the detected observations. In this way, a number of potential outliers can be identified and eliminated in each iteration of an adjustment. This leads to higher efficiency in data snooping of geodetic networks. The technique is illustrated with some numerical examples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00863621
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  • 4
    Electronic Resource
    Electronic Resource
    Sensitivity analysis in Gauss-Markov models (1996)
    Springer
    Journal of geodesy 70 (1996), S. 480-488 
    Details
    ISSN: 1432-1394
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract. The estimated parameters from a Gauss-Markov model have varying sensitivity to the individual observations included in the model. Similarly, the redundancy contribution (number) of any observation is associated differently to all the other observations in the model. Evaluation of the sensitivity of parameters to observations, and the sensitivity of the redundancy contribution of one observation to the others are useful to gain more insight into Gauss-Markov models. Such analysis has found practical applications in survey network design and in multiple outlier detections. This paper presents some quantitative sensitivity measures for general Gauss-Markov models. The application of the concept in surveying network design is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00863620
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  • 5
    Electronic Resource
    Electronic Resource
    Petrology and retrograde P-T path for eclogites of the Maksyutov Complex, Southern Ural Mountains, Russia (1995)
    Oxford, UK : Blackwell Publishing Ltd
    The @island arc 4 (1995), S. 0 
    Details
    ISSN: 1440-1738
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Abstract The Maksyutov Complex, situated in the southern Ural Mountains of Russia, is the first location where quartz aggregates within garnets exhibiting radial fractures were identified as coesite pseudomorphs (Chesnokov & Popov 1965). The complex consists of two tectonic units: a structurally lower eclogite-bearing schist unit and an overlying meta-ophiolite unit. Both units show evidence for multiple stages of metamorphism and deformation. The high-pressure metamorphism of the eclogite-bearing schist unit, discussed in this report, is suspected to be related to a collision between the Russian platform and a fragment of the Siberian continent during the early Cambrian. At least three stages of metamorphism (M1-3) and two stages of deformation (S1 and S2) were observed in thin sections: M1) garnet (Alm55-60, Prp22-28, Grs16-20) + omphacite (Jd46-56) + phengite (Si ≅ 3.5) + rutile; M2) garnet + glaucophane ± lawsonite + white mica; and M3) epidote + chlorite ± albite ± actinolite + white mica. Observed mineral parageneses define a retrograde P-T path for the eclogite. Mineral assemblages within the most representative eclogite from the lower unit of the Maksyutov Complex indicate minimum peak pressures of 15 kbar at temperatures of approximately 600°C. If the presence of coesite pseudomorph is confirmed, the peak ultrahigh-pressure metamorphism may be as high as 27 kbar at 615°C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1440-1738.1995.tb00148.x
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  • 6
    Electronic Resource
    Electronic Resource
    Geotectonic evolution of diamondiferous paragneisses, Kokchetav Complex, northern Kazakhstan: The geologic enigma of ultrahigh-pressure crustal rocks within a Paleozoic foldbelt (1995)
    Oxford, UK : Blackwell Publishing Ltd
    The @island arc 4 (1995), S. 0 
    Details
    ISSN: 1440-1738
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Abstract The Kokchetav Complex is a tectonic mega-melange consisting of seven pre-Ordovician units (units I-VII) of contrasting lithologies and P–T conditions of metamorphism, overlain and/or intruded by four post-recrystallization entities. Most of the constituent rock types display affinities with continental crust; paraschists and paragneisses, which carry biogenically produced carbon, clearly were laid down near the surface of the Earth. Microdiamond (and rare coesite) inclusions are contained in strong, refractory garnet, zircon, clinopyroxene, and kyanite, some of the constituent neoblastic phases of this metasedimentary unit. Systematic mineral parageneses and textural relationships support the hypothesis that the metamorphic assemblages represent a close approach to chemical equilibrium at the time of formation. Metamorphism of diamond-bearing paragneisses and schists transpired at 535 ± 5 Ma; physical conditions included minimum pressures of 40 kbar and temperatures exceeding 900 °C. Other associated units contain mineralogic evidence of somewhat lower to considerably lower pressures and temperatures: observed magnesite + diopside pairs, coesite, grossular-pyropic garnet, potassic clinopyroxene, Si-rich phengite, barroisite-crossite(?), aluminous titanite and/or Al-rutile, and the assemblage talc + kyanite + garnet all testify to relatively elevated pressures of formation. The metamorphosed lithotectonic units represent individual, discrete stages in what initially may have been a continuous P-T series, but intense post-metamorphic dislocation has resulted in the preservation of a chaotically mixed sequence rather than an unbroken gradation in preserved conditions of metamorphism. Only units I-III, and probably VIb may represent portions of a dismembered subduction zone lithologie assemblage. The uplift to mid-crustal levels and cooling of the mega-melange took place by about 515–517 Ma, at which time the complex was stabilized as a part of the Kazakhstan microcontinental collage. An hypothesized Late Vendian-Early Cambrian subduction of the Kazakhstan-North Tianshan(?) microcontinental salient to depths exceeding 125 km, followed by decoupling from the descending oceanic crust-capped lithospheric plate is held responsible for the ultrahigh-pressure metamorphism of the Kokchetav Complex. Inasmuch as vestiges of a calc-alkaline volcanic/plutonic arc of approximately Early Cambrian age are preserved as only scattered relics in the general region, the plate-tectonic setting may have involved an intra-oceanic, Marianas-type, incipient arc which was subsequently removed through transform faulting or erosion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1440-1738.1995.tb00149.x
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  • 7
    Electronic Resource
    Electronic Resource
    Metamorphic evolution of diamond-bearing and associated rocks from the Kokchetav Massif, northern Kazakhstan (1997)
    Oxford, UK : Blackwell Science Ltd.
    Journal of metamorphic geology 15 (1997), S. 0 
    Details
    ISSN: 1525-1314
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Representative diamond-bearing gneisses and dolomitic marble, eclogite and Ti-clinohumite-bearing garnet peridotite from Unit I at Kumdy Kol and whiteschist from Unit II at Kulet, eastern Kokchetav Massif, northern Kazakhstan, were studied. Diamond-bearing gneisses contain variable assemblages, including Grt+Bt+Qtz±Pl±Kfs±Zo±Chl±Tur±Cal and minor Ap, Rt and Zrn; abundant inclusions of diamond, graphite+chlorite (or calcite), phengite, clinopyroxene, K-feldspar, biotite, rutile, titanite, calcite and zircon occur in garnet. Diamond-bearing dolomitic marbles consist of Dol+Di±Grt+Phl; inclusions of diamond, dolomite±graphite, biotite, and clinopyroxene were identified in garnet. Whiteschists carry the assemblage Ky+Tlc+Grt+Rt; garnet shows compositional zoning, and contains abundant inclusions of talc, kyanite and rutile with minor phlogopite, chlorite, margarite and zoisite. Inclusions and zoning patterns of garnet delineate the prograde P–T  path. Inclusions of quartz pseudomorphs after coesite were identified in garnet from both eclogite and gneiss. Other ultrahigh-pressure (UHP) indicators include Na-bearing garnet (up to 0.14 wt% Na2O) with omphacitic Cpx in eclogite, occurrence of high-K diopside (up to 1.56 wt% K2O) and phlogopite in diamond-bearing dolomitic marble, and Cr-bearing kyanite in whiteschist. These UHP rocks exhibit at least three stages of metamorphic recrystallization. The Fe-Mg partitioning between clinopyroxene and garnet yields a peak temperature of 800–1000 °C at P 〉40 kbar for diamond-bearing rocks, and about 740–780 °C at 〉28–35 kbar for eclogite, whiteschist and Ti-bearing garnet peridotite. The formation of symplectitic plagioclase+amphibole after clinopyroxene, and replacement of garnet by biotite, amphibole, or plagioclase mark retrograde amphibolite facies recrystallization at 650–680 °C and pressure less than about 10 kbar. The exsolution of calcite from dolomite, and development of matrix chlorite and actinolite imply an even lower grade greenschist facies overprint at c. 420 °C and 2–3 kbar. A clockwise P–T  path suggests that supracrustal sediments together with basaltic and ultramafic lenses apparently were subjected to UHP subduction-zone metamorphism within the diamond stability field. Tectonic mixing may have occurred prior to UHP metamorphism at mantle depths. During subsequent exhumation and juxtaposition of many other tectonic units, intense deformation chaotically mixed and mylonitized these lithotectonic assemblages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1525-1314.1997.00035.x
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  • 8
    Electronic Resource
    Electronic Resource
    On the satellite altimeter crossover problem (1997)
    Springer
    Journal of geodesy 71 (1997), S. 83-96 
    Details
    ISSN: 1432-1394
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract. Mean sea surface heights and residual radial orbit errors are estimated simultaneously in a single global crossover adjustment of multiple cycles of satellite altimetry data. The rank defect inherent in the estimation problem is explicitly identified and treated in various ways to give solutions that minimise (in norm) either orbit errors or mean sea surface heights. The rank defect gives rise to geographically correlated orbit error, consisting of those components of the orbit error or those components of the map of sea surface heights which fall within the nullspace of the estimation problem and which cannot be distinguished as orbit error or ocean signal. We show that, in the case of Topex/Poseidon data, the geographically correlated error consists largely of long-wavelength and long-period sea surface fluctuations, which in the past has often been assigned as orbit error.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001900050077
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  • 9
    Electronic Resource
    Electronic Resource
    Local crossover analysis of exactly repeating satellite altimeter data (1997)
    Springer
    Journal of geodesy 72 (1997), S. 31-43 
    Details
    ISSN: 1432-1394
    Keywords: Key words. Crossover ; Satellite altimeter ; Sea surface height
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract. The crossover adjustment plays a central role in the processing of satellite altimeter measurements. The usual procedure is to form sea surface height differences at crossover points, solve for the radial orbit error (with due attention to the singular nature of the estimation problem) and then to construct altimetric sea-level maps using the mean sea surface heights at the crossover points. Our approach is very different, to make direct use of measurements at crossover points without differencing and to estimate simultaneously orbit parameters, mean sea surface height and sea surface height variability in a single, unified adjustment. The technique is suited for repeat data over an area small enough that adjoining passes may be considered to be parallel and to permit the solution of a set of linear equations of dimension equal to the number of crossover points. The size of the numerical problem is almost independent of the number of repeat cycles of the altimeter mission. Explicit recognition is given to the rank defect of the least-squares estimation problem; we show that, for an orbit model with r parameters, the rank defect of the local crossover problem is exactly r 2. The defect may be overcome by choosing an appropriate set of constraints – either giving a best fit of mean sea surface heights to a reference surface, or minimising orbit parameters, or a minimum norm solution in which both mean sea surface heights and orbit parameters are minimised. There is no need to choose a reference pass, all passes are treated equally and data gaps are easily accommodated. Numerical results are presented for the south-western Indian Ocean, based on the first 2 years of altimeter data from the Geosat Exact Repeat Mission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001900050145
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  • 10
    Electronic Resource
    Electronic Resource
    Cabbage (Brassica oleracea var. Capitata) fails to show wound-induced defence against a specialist and a generalist herbivore? (1996)
    Springer
    Oecologia 108 (1996), S. 105-112 
    Details
    ISSN: 1432-1939
    Keywords: Herbivory ; Wound-induced defence ; Cabbage ; Pieris brassicae ; Spodoptera littoralis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper presents tests of a model of wound-induced defence in herbaceous plants. Many studies have reported both chemical changes in leaves and changes in the behaviour and/or physiology of herbivores as a result of wounding leaves. These studies and others have led to the development of various models to explain wound-induced effects both in terms of plant response and herbivore behaviour. The model under test was proposed by Edwards and Wratten (1987) and predicts that wounding a plant will cause herbivores (1) to take more meals of a smaller size and/or consume less foliage overall (2) grow more slowly and (3) be more mobile. These predictions were tested in cabbage Brassica oleracea L. var. Capitata cv. Pixie with Pieris brassicae L. (Lepidoptera: Pieridae) as a herbivore specialising on cabbage, and Spodoptera littoralis Boisd. (Lepidoptera: Noctuidae) as a generalist herbivore. Both insects showed some reduction in consumption of leaves from upper parts of the plant, but no change in meal size. There were no effects on the growth or mobility of either species as a result of wounding foliage. These results are discussed in relation to the predictions of the model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333221
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