Journal Articles

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Browsing Journal Articles by Author "Aduol, Francis O."

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    An evaluation of some robust estimation techniques in the estimation of geodetic parameters.
    (1999) Aduol, Francis O.
    In Part 1 of this study, we reported on an evaluation of the performances of four robust estimation techniques, namely: the modified residuals technique, the modified weights technique, the modified residuals-weights technique, and the iterative weighting technique. The methods were then tested on a simulated geodetic network. In this second part of the study, we carry out a further evaluation of the methods with a real geodetic network as the test network. In order that a set of gross-error contaminated observational may be available for the study, gross errors have been simulated into observational set. The results of the study largely corroborate the findings in Part 1 of the study
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    Financing public universities in Kenya: a model based on rationalised student unit costs and staffing
    (2001) Aduol, Francis O.
    Whitehead (1967:4) defines the term “Education is t he acquisition of the art of the utilization of knowledge.” The universities are those institutions that teach learners the art of the utilization of knowle dge. For this to be achieved, goals and objectives are set in such a way that at a certain time 3 or 4 years, an individual is said to acquire the basic art at u ndergraduate level. If still interested, the individual can continue to higher l evels. This basic level and other levels above it are referred as higher educa tion. In this paper, the term university will be used to refer higher education. The art of the teaching and learning process requir es the appropriate media to communicate the curriculum content in this paper, the term communication simply refers to the art of sending o r receiving messages. Development of any nations depends on the participa tion of its human resources. This need well qualified personnel to handle all matters pertaining to her specific needs. Education in deve loping countries has expanded tremendously from few secondary schools at independence to the vast numbers that we have today. Most of the Africa n countries had either one or two universities at independence or none at all. However, this trend has changed and the countries can be congratulated for making sure that their people/citizens have access to higher education
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    A model for estimating student unit cost and staffing requirements for university programmes with reference to Kenyan public universities.
    (2001) Aduol, Francis O.
    A model for the estimation of student unit costs and the staffing requirements for university academic programmes is presented. The development of the model starts off with the specification of a staff distribution matrix, which sets out the proportions of the various staff levels in a given staff category that are needed to service at a particular degree level. The categories of staff considered are teaching (academic), senior administrative, technical, clerical, and semi-skilled. Within a given category of staff are considered various staff levels, e.g. Professor, Senior Lecturer and Lecturer in the case of the teaching staff category. The academic programmes are considered to be taken at the Bachelor's, Master's and the Doctorate degree levels. Ratios between numbers of staff in a given level within a category, as well as ratios of staff within the category needed to service at the various degree levels are specified a priori. Academic (teaching) student-staff ratios for the various programmes are also set out a priori. Student-staff ratios for the other categories of staff are then computationally derived from the academic student-staff ratios. For each staff category a staff distribution matrix is then worked out. With the staff distribution matrix thus specified, the student unit cost and staffing requirement for a given academic programme are computed through various manipulations on the matrix. As a test example, the model is used to estimate student unit cost and staffing requirements for the six public universities in Kenya
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    A model for the establishment of an integrated regional geodetic datum
    (1993) Aduol, Francis O.
    A model for the establishment of an integrated geodetic datum covering a region is treated. The integrated geodetic datum is understood here to comprise the geoid, the reference ellipsoid, and the positional coordinates. A comprehensive unified solution model including the three parameters comprising the datum is considered. The estimation model adopted rigorously incorporates determined prior information in the estimation of the datum parameters. Mathematical models together with the pertinent observation equations are presented, followed by a description of the procedure for the actual setting up of the datum. The observational scheme is based on a system of modular traverses anchored on a trilateration of GPS baselines.
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    Robust geodetic parameter estimation through iterative weighting
    (1994) Aduol, Francis O.
    A procedure for robust linear estimation of parameters on the basis of iterative weighting of observations is presented. The approach considers the weights of observations as not just functions of the observational variances, but as functions of both the observational variances and estimates of the observational residuals. However, as the residuals are themselves functions of the estimates of the unknown parameters, the entire estimation procedure is performed iteratively. Three test examples comprising a linear point estimation, a linear regression case, and a geodetic network have been adopted to demonstrate the procedure. The results indicate that the proposed approach is effective in the isolation and management of outliers, and further that the robust estimation is in general a more efficient estimation procedure than the ordinary least squares.
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    Robust Geodetic Parameter Estimation Under Least Squares Through Weighting on the Basis of the Mean Square Error
    (2003) Aduol, Francis O.
    A technique for the robust estimation of geodetic parameters under the least squares method when weights are specified through the use of the mean square error is presented. The mean square error is considered in the specification of observational weights instead of the conventional approach based on the observational variance. The practical application of the proposed approach is demonstrated through computational examples based on a geodetic network. The results indicate that the least squares estimation with observational weights based on the mean square error is relatively robust against outliers in the observational set, provided the network (or the system) under consideration has a good level of reliability, as to make the network (or system) stable under estimation
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    A static dynamic model for densification of geodetic networks.
    (1993) Aduol, Francis O.
    in the tradition of several joint papers by the honoree and myself, including E. Grafarend and B. Schaffrin (1974, 1976, 1988) and E. Grafarend, B. Schaffrin, and E. Knickmeyer (1982), I took up the subject again in B. Schaffrin (1984, 1989), N. Tamim and B. Schaffrin (1995) and B. Schaffrin and J. Cothren (1998), now with the emphasis on network densification methods which are rigorous, but which leave tie points unchanged along with their variances and covariances. Such a requirement led to the notion of “reproducing estimators” as first presented by B. Schaffrin (1997). It has been known for a long time that the so-called “dynamic adjustment” of geodetic networks can be interpreted as least-squares collocation, according to H. J. Buiten (1978), which would not yield estimates with the “reproducing property.” Also the “free net adjustment” followed by a Helmert transformation would not per se guarantee identical tie point coordinate estimates unless we “forget” about the deviations whose norm we had minimized, but usually not to zero. So the only “reprodu c - ing” alternative seemed to be given by the formulas of a classical least-squares adjustment with fixed constraint even though the tie points are “ fiducial” in their nature, having typically a full dispersion matrix. Therefore, in the formula for the corresponding variance-covariance matrix we find an add i - tional term which vanishes as soon as the “ fiducial” points become real “fixed” points; see, for i n - stance, B. Schaffrin (1984, 1989). This apparently has been the method, applied by JPL over the years, when they talked about “ fiducial network strategies” as in S. M. Lichten et al. (1989), for instance, without spelling out exactly what they did. In any case, as could have been expected, the latter one was shown not to be the optimal estimator with the “reproducing property” by B. Schaffrin (1997). Instead, the optimum turned out to be the “forgetful dynamic adjustment” where every densification point is found conventionally through least- squares collocation, but the tie points remain unchanged. Consequently, a free adjustment followed by a “forgetful Helmert transformation” must be considered inferior and may no longer be carried out routinely; see also K. R. Koch (1983) and F. W. O. Aduol (1993). Here we try to employ least-squares methodology to generate that “reproducing estimator” which, as we already know, will be optimal in this class
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    The surveying profession beyond the Year 2000 and the Kenyan surveyor.
    (2000) Aduol, Francis O.
    An overview of geospatial information education and its development in Kenya in general and Jomo Kenyatta University of Agriculture and Technology (JKUAT) in particular is given. The gradual evolution and conception, design and establishment of Geomatic Engineering and Geospatial Information Systems (GIS) training programmes at Jomo Kenyatta University is discussed. The impetus of this growth, envisaged direction, expected impact on the practice of Geomatic Engineering, GIS and associated disciplines in Kenya and the Eastern Africa Region are explored. The anticipated challenges and strategies for meeting the same are discussed