25,083 research outputs found

    Keynote address

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    Approved and projected probe mission strategies for the outer planet exploration programs are briefly outlined

    The generic task toolset: High level languages for the construction of planning and problem solving systems

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    The current generation of languages for the construction of knowledge-based systems as being at too low a level of abstraction is criticized, and the need for higher level languages for building problem solving systems is advanced. A notion of generic information processing tasks in knowledge-based problem solving is introduced. A toolset which can be used to build expert systems in a way that enhances intelligibility and productivity in knowledge acquistion and system construction is described. The power of these ideas is illustrated by paying special attention to a high level language called DSPL. A description is given of how it was used in the construction of a system called MPA, which assists with planning in the domain of offensive counter air missions

    The impact of trade liberalisation on South African agricultural productivity

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    This study attempts to examine the empirical relationship between trade and total factor productivity (TFP) in the agricultural sector using both cross -sectiona, (across nine agricultural commodities), and time -series analysis. The Error Correction Model of ordinary least square (OLS) results from the cross -sectional analysis confirm that export shares and capital formation were found to be positive and significant; whereas, import shares and real exchange rate were found to be related negatively. However, the net effect of export and import shares had a positive effect. This implies that trade liberalisation causes productivity gains. Moreover, the time -series analysis goes in the same direction as the cross -sectional results, showing that there is a robust relationship among TFP, degree of openness, and capital formation. Whereas, debt was found to be inversely related, this implies that agricultural industries / farmers lack debt management skills.TFP, OLS, Trade liberalization or degree of openness, capital formation, International Relations/Trade,

    Optimisation of different land use regimes in the Mhala district

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    Communal, commercial and nature conservation land use alternatives occur together at the perimeter of Manyeleti Game Reserve in Mhala district. The different land use alternatives were compared with one another with the purpose of determining the best possible land use. Communal households and the Seville scheme households perform poorly in support of household welfare. This holds disastrous implications for future generations if nothing is done. The Uthla scheme households perform better and generate larger incomes, but at the expense of communal households. Both schemes are highly subsidised by government. Manyeleti Game Reserve is mismanaged and the worst land use alternative in the area, providing no benefit to people living at its perimeter and needs government support for its continued survival. Using multi criteria analysis a combination of communal and conservation land use alternatives is found to be the best alternative, maximising the communities' welfare and conserving the environment.Land Economics/Use,

    Water markets an alternative for central water allocation?

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    South Africa is entering a whole new era in water management. In the face of efforts to curtail runaway government spending and protect the environment, water institutions must foster the conservation and efficient allocation of existing supplies. They must also take water's growing recreational and environmental value into account. The crucial question is, can the current water institutions meet today's requirements? Despite the resulting inefficiency and waste, traditional resource economists continue to identify taxes, regulations, subsidies, and governmental allocation as solutions to today's water problems. Internationally, there is enough evidence to prove that central allocation with almost any resource gave rise to gross inefficiency. The main reason is the distortions on the value placed on resources within such a centralised planning environment. Resources are either valued to high or to low. What is the value of freshwater and how can water be allocated in such a way as to reflect the scarcity value of water? A non-linear spatial equilibrium model was developed to simulate the impact of a potential water market in the Upper-Berg River: Western Cape. This paper explores water markets as an alternative to central water allocation decisionsResource /Energy Economics and Policy,

    Sensible and latent heating of the atmosphere as inferred from DST-6 data

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    The average distribution of convective latent heating, boundary layer sensible heat flux, and vertical velocity are determined for the winter 1976 DST period from GLAS model diagnostics. Key features are the regions of intense latent heating over Brazil, Central Africa, and Indonesia; and the regions of strong sensible heating due to air mass modification over the North Atlantic and North Pacific Oceans
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