9,825 research outputs found

    Swaziland die Geologie en Geografie van Swaziland

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    In 1943 het die eerste werklike grootskaalse kartering van die gebied 'n aanvang geneem. En van 1949 af, met die koms van die eerste stel lugfoto’s, is hierdie tempo versnel. Die basiese opname van die gebied is dan ook in 1957 voltooi. In die eerste stadiums van kartering is die klassifikasie van die verskillende rotstopes gevolg soos wat dit deur Hall en later Van Eeden gedoen is. Soos die werk gevorder het, is veranderings ingevoer om die klassifikasie aan te pas by plaaslike omstandighede, maar nie almal hiervan het die toets van die tyd deurstaan nie

    Decision systems : the relation between problem specification and mathematical analysis

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    In this paper it is demonstrated that automated support for decision making of a tactical or strategic nature requires a solver-independent medium for describing decision situations. Such a medium may be specific for one environment, but it is also possible to develop media for certain types of environments. By using such a medium one obtains a decoupling of problem formulation and method of analysis. This makes it possible to use (parts of) the problem formulation as input for different types of models. Such problem formulations may provide mathematical models themselves, although they might also contain some less formal features. The decoupling makes it possible to choose problem formulations which are much closer to the original decision situation than would otherwise be possible with formulations in terms of a preselected solver. The argumentation is illustrated by treating a language for specifying goods flow problems in some detail. This language is based on timed coloured Petri-nets

    Decision support for natural resource management; models and evaluation methods

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    When managing natural resources or agrobusinesses, one always has to deal with autonomous processes. These autonomous processes play a core role in designing model-based decision support systems. This chapter tries to give insight into the question of which types of models might be used in which cases. It does so by formulating a rough categorization of decision problems and providing many examples. Particular attention is given to the role of statistical learning theory, which may be used to replace mathematical modeling by training with example

    Kansen

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    Markov programming by successive approximations with respect to weighted supremum norms

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    Markovian decision processes are considered in the situation of discrete time. countable state space. and general decision space. By introducing a Banach space with a weighted supremum norm, conditions are derived, which guarantee convergence of successive approximations to the value function. These conditions are weaker then those required by the usual supnorm approach. Several properties of the successive approximations are derived

    A Lindley-type equation arising from a carousel problem

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    In this paper we consider a system with two carousels operated by one picker. The items to be picked are randomly located on the carousels and the pick times follow a phase-type distribution. The picker alternates between the two carousels, picking one item at a time. Important performance characteristics are the waiting time of the picker and the throughput of the two carousels. The waiting time of the picker satisfies an equation very similar to Lindley's equation for the waiting time in the PH/U/1 queue. Although the latter equation has no simple solution, we show that the one for the waiting time of the picker can be solved explicitly. Furthermore, it is well known that the mean waiting time in the PH/U/1 queue depends on to the complete interarrival time distribution, but numerical results show that, for the carousel system, the mean waiting time and throughput are rather insensitive to the pick-time distribution.Comment: 10 pages, 1 figure, 19 reference

    The ALICE Transition Radiation Detector

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    In this talk an overview of the ALICE TRD is presented. The ALICE TRD consists of 540 individual detector modules with a total of 1.2 million readout channels. It allows electron identification above a momentum of 1 GeV/c and is capable of providing a very fast and efficient trigger on electrons with large transverse momentum pt. It will operate in a very high multiplicity environment. The rapidity density of charged particles in collisions of Pb nuclei at ps = 5:5 ATeV is expected to be as high as dN/dy = 8000

    Engaging Old Testament prophetic literature in traumatic times of loss and grief

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    This article addresses not only the matter of loss and grief but also hope and recovery. The coronavirus disease 2019 (COVID-19) has hugely affected not only South Africans but also people globally. One of the key features of this pandemic is loss and the associated grief. To explore these topics, the author has engaged prophetic literature, more specifically the books of Isaiah and Jeremiah, which present compelling cases of loss and grief. An attempt was made to identify similarities between the experiences of the people of Judah and our current experiences of loss and grief because of the pandemic. Whilst the reality of loss and grief is validated, the positive role of prophetic words of comfort and hope is also valued. Contribution: This article offers original research in the field of biblical studies, more specifically, in the field of the Old Testament. This is in line with the scope of the article aims at relating texts from the prophetic literature to a current challenging situation of grief and loss because of the COVID-19 pandemic
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