The use of hypertext in the writing of group papers

Abstract The Virtual Constructing Tool (VCT) was developed at the Nijmegen School of Management in 1998. The VCT is intended to facilitate the process of writing group papers through the use of construction and communication tools and is based completely on the Internet. The VCT allows a paper to be structured by means of hyperlinking and cooperation between students. Students are allowed to divide tasks, but they are held responsible for the quality of the arguments in the paper as a whole. They are invited to spend time in dealing with validity claims and in building a valid train of thought. Producing a group paper includes four interrelated working processes: exploring the subject, exchanging information, arguing and discussing and editing. Hyperlinking offers a contribution in each of these processes which varies from associative linking of pieces of information to strengthening linear structuring. Therefore, a different perspective has been taken to that of those authors who consider hyperlinking as a tool par excellence for the nonlinear production of information.     

State Observation and Diagnosis of Discrete-Event Systems Described by Stochastic Automata

The problems ofstate observation and diagnosis are solved for discrete–eventsystems, which are described by stochastic automata. As manysystems are not observable in the sense that it is possible toreconstruct the state unambiguously, the observation problemis set up as the problem of determining the smallest possibleset of states that are compatible with the measured input andoutput sequences. The diagnostic problem is shown to be, in principle,an observation problem. Conditions for the observability anddiagnosability of stochastic automata are presented. The resultsare illustrated by examples.     

Evolving combinatorial problem instances that are difficult to solve

This paper demonstrates how evolutionary computation can be used to acquire difficult to solve combinatorial problem instances. As a result of this technique, the corresponding algorithms used to solve these instances are stress-tested. The technique is applied in three important domains of combinatorial optimisation, binary constraint satisfaction, Boolean satisfiability, and the travelling salesman problem. The problem instances acquired through this technique are more difficult than the ones found in popular benchmarks. In this paper, these evolved instances are analysed with the aim to explain their difficulty in terms of structural properties, thereby exposing the weaknesses of corresponding algorithms.     

Primary reconstruction of the mandible after resection for oral cancer

Forty-seven patients with cancer of the lower half of the oral cavity underwent primary restoration of mandibular continuity with a threaded wire after "en bloc" resection. The overall 3 years tolerance rate of the wire calculated according to the actuarial method is 0.29. Preoperative radiotherapy and inclusion of the wire into silastic reduced tolerance of the prosthesis. The occurrence of an oral fistula required removal of the wire.     

Inhibition effect of swine wastewater heavy metals and antibiotics on anammox activity

The feasibility of anaerobic ammonium oxidation (anammox) process to treat wastewaters containing antibiotics and heavy metals (such as the liquid fraction of the anaerobically digested swine manure) was studied in this work. The specific anammox activity (SAA) was evaluated by means of manometric batch tests. The effects of oxytetracycline, sulfathiazole, copper and zinc were studied. The experimental data of the short-term assays were fitted with an inhibition model to identify the half maximal inhibitory concentration (IC(50)). After 24 h exposures, IC(50)-values equal to 1.9, 3.9, 650 and 1,100 mg L(-1) were identified for copper, zinc, sulfathiazole and tetracycline respectively. The effect of prolonged exposure (14 days) to oxytetracycline and sulfathiazole was studied by means of repeated batch-assays. Anabolism and catabolism reactions were active during the inhibition tests indicating that anammox bacteria could grow even in the extreme conditions tested. Considering the average concentrations expected in swine wastewaters, the inhibitors studied do not seem to represent a problem for the application of the anammox process. However, in order to verify the effect of these compounds on the growth of anammox bacteria, continuous culture experiments could be conducted.     

Democratic Legitimacy of New Forms of Water Management in the Netherlands

Due to changes in the Dutch flood management paradigm, governance practices have been shifting from technocratic and state-oriented towards more collaborative governance approaches in which many governmental actors, together with private and societal actors, search out integral solutions. This shift has had an impact on how water management is legitimized. This paper evaluates two water governance processes that reflect the new management paradigm in different ways, and analyzes how these changing paradigms influence the democratic legitimacy of water governance. It is concluded that the extent to which the new paradigm is implemented influences the way in which democratic legitimacy is organized. It is also shown that new forms of democratic legitimacy do not replace existing ones but rather contribute to hybrid and contextualized forms of legitimacy.     

The use of NDVI and its Derivatives for Monitoring Lake Victoria’s Water Level and Drought Conditions

Normalized Difference Vegetation Index (NDVI), which is a measure of vegetation vigour, and lake water levels respond variably to precipitation and its deficiency. For a given lake catchment, NDVI may have the ability to depict localized natural variability in water levels in response to weather patterns. This information may be used to decipher natural from unnatural variations of a given lake’s surface. This study evaluates the potential of using NDVI and its associated derivatives (VCI (vegetation condition index), SVI (standardised vegetation index), AINDVI (annually integrated NDVI), green vegetation function (F _g ), and NDVIA (NDVI anomaly)) to depict Lake Victoria’s water levels. Thirty years of monthly mean water levels and a portion of the Global Inventory Modelling and Mapping Studies (GIMMS) AVHRR (Advanced Very High Resolution Radiometer) NDVI datasets were used. Their aggregate data structures and temporal co-variabilities were analysed using GIS/spatial analysis tools. Locally, NDVI was found to be more sensitive to drought (i.e., responded more strongly to reduced precipitation) than to water levels. It showed a good ability to depict water levels one-month in advance, especially in moderate to low precipitation years. SVI and SWL (standardized water levels) used in association with AINDVI and AMWLA (annual mean water levels anomaly) readily identified high precipitation years, which are also when NDVI has a low ability to depict water levels. NDVI also appears to be able to highlight unnatural variations in water levels. We propose an iterative approach for the better use of NDVI, which may be useful in developing an early warning mechanisms for the management of lake Victoria and other Lakes with similar characteristics.     

An ENO-Based Method for Second-Order Equations and Application to the Control of Dike Levels

This work aims to model the optimal control of dike heights. The control problem leads to so-called Hamilton-Jacobi-Bellman (HJB) variational inequalities, where the dike-increase and reinforcement times act as input quantities to the control problem. The HJB equations are solved numerically with an Essentially Non-Oscillatory (ENO) method. The ENO methodology is originally intended for hyperbolic conservation laws and is extended to deal with diffusion-type problems in this work. The method is applied to the dike optimisation of an island, for both deterministic and stochastic models for the economic growth.