An Adaptive Identification and Prediction Algorithm for the Real-Time Forecasting of Hydrologic Time Series

In order to achieve the effective control of water resources systems, one must know the future behavior of the inputs to that particular system. Because of the uncertainties inherent in water resources processes, the prediction algorithm, to be constructed, should include stochastic elements, too. Moreover, the algorithm should be recursive to avoid cumbersome computations and to be able for real-time forecasting. In this paper we present a method which is applicable for both linear and nonlinear hydrologic systems having not completely time-invariant properties. The algorithms are based on the state space description of the processes involved and utilize the Kalman stochastic filtering technique. Due to the unknown nature of noise processes, the basic algorithms were changed to be adaptive. Using the algorithms the joint handling of water quantity and quality data becomes feasible

On the Optimal Adaptive Parameter Estimation Of Water Resources Control Systems

As water resource systems have grown larger and more complex, the importance of optimum operation of these systems has increased. Several IIASA papers have been published attacking these problems which are in essence, the problems of estimating/controlling the state of WR systems. J. Casti gave algorithms for the stochastic inflow-nonlinear objective reservoir control problem; A. Szollosi-Nagy outlined the closed-loop control of linear stochastic water quality systems with quadratic performance measure; and quite recently, K. Takeuchi dealt with the problem of typhoon forecasting using stochastic filtering techniques. There is at least one aspect which is common to these approaches, and that is the way they look at the dynamics of the water resource systems

Mutant cycles at CFTR's non-canonical ATP-binding site support little interface separation during gating

Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel belonging to the adenosine triphosphate (ATP)-binding cassette (ABC) superfamily. ABC proteins share a common molecular mechanism that couples ATP binding and hydrolysis at two nucleotide-binding domains (NBDs) to diverse functions. This involves formation of NBD dimers, with ATP bound at two composite interfacial sites. In CFTR, intramolecular NBD dimerization is coupled to channel opening. Channel closing is triggered by hydrolysis of the ATP molecule bound at composite site 2. Site 1, which is non-canonical, binds nucleotide tightly but is not hydrolytic. Recently, based on kinetic arguments, it was suggested that this site remains closed for several gating cycles. To investigate movements at site 1 by an independent technique, we studied changes in thermodynamic coupling between pairs of residues on opposite sides of this site. The chosen targets are likely to interact based on both phylogenetic analysis and closeness on structural models. First, we mutated T460 in NBD1 and L1353 in NBD2 (the corresponding site-2 residues become energetically coupled as channels open). Mutation T460S accelerated closure in hydrolytic conditions and in the nonhydrolytic K1250R background; mutation L1353M did not affect these rates. Analysis of the double mutant showed additive effects of mutations, suggesting that energetic coupling between the two residues remains unchanged during the gating cycle. We next investigated pairs 460-1348 and 460-1375. Although both mutations H1348A and H1375A produced dramatic changes in hydrolytic and nonhydrolytic channel closing rates, in the corresponding double mutants these changes proved mostly additive with those caused by mutation T460S, suggesting little change in energetic coupling between either positions 460-1348 or positions 460-1375 during gating. These results provide independent support for a gating model in which ATP-bound composite site 1 remains closed throughout the gating cycle

Introductory Remarks on the State Space Modeling of Water Resource Systems

In section 1 the notion of state and state equations for water resource systems are discussed both for continuous and discrete dynamics. Section 2 presents the solution of state equation for linear systems including the derivation of state transition and impulse response matrices. In section 3 the structural properties such as observability, controllability, indentifiability and minimal realizations are discussed. Finally, in section 4 the state concept for stochastic systems is reexamined. The state and measurement disturbances are considered as being white Gaussian noise processes and it is showed how the case of sequentially correlated uncertainties can be reduced to an augmented system model having white Gaussian state disturbance only. The paper concludes with the generalization of structural properties for stochastic systems. To illustrate the underlying concepts examples taken from a broad range of water resources problems, such as rainfall analysis, rainfall/runoff relation, reservoir and lake/aquifer problems, water quality control etc., are presented

Workshop on the Vistula and Tisza River Basins, 11-13 February 1975

This is the written version of presentations that were delivered in February 1975 at the IIASA Workshop on the Vistula and Tisza River Basins. The contributions reproduced here were prepared by IIASA scholars and by our guests, scientists from Hungarian and Polish research institutions. In accordance with the results of the IIASA Planning Conference in June 1973, the Water Project has focused its attention on specific universal methodological problems of water resources development and optimal operation. Large-scale demonstrations or problems and methods of river basin management represent an important part of this research program. The Tisza and Vistula case studies provide an excellent framework for discussing the practical significance of methodological developments

Is it time for studying real-life debiasing? Evaluation of the effectiveness of an analogical intervention technique.

The aim of this study was to initiate the exploration of debiasing methods applicable in real-life settings for achieving lasting improvement in decision making competence regarding multiple decision biases. Here, we tested the potentials of the analogical encoding method for decision debiasing. The advantage of this method is that it can foster the transfer from learning abstract principles to improving behavioral performance. For the purpose of the study, we devised an analogical debiasing technique for 10 biases (covariation detection, insensitivity to sample size, base rate neglect, regression to the mean, outcome bias, sunk cost fallacy, framing effect, anchoring bias, overconfidence bias, planning fallacy) and assessed the susceptibility of the participants (N = 154) to these biases before and 4 weeks after the training. We also compared the effect of the analogical training to the effect of 'awareness training' and a 'no-training' control group. Results suggested improved performance of the analogical training group only on tasks where the violations of statistical principles are measured. The interpretation of these findings require further investigation, yet it is possible that analogical training may be the most effective in the case of learning abstract concepts, such as statistical principles, which are otherwise difficult to master. The study encourages a systematic research of debiasing trainings and the development of intervention assessment methods to measure the endurance of behavior change in decision debiasing

On the Optimal Stochastic Control of Water Resources Systems

To get an effective control of large river basin systems, the decision maker wishes to develop optimal operating policies. To establish these policies, the future behavior of inputs, such as available resources, demand to be satisfied, etc., must be known or rather predicted. Because of the uncertainties inherent in water resources (WR) processes, both in quantity and quality, the prediction scheme to be constructed should be able to handle stochastic effects. Moreover, the algorithms should be recursive to avoid cumbersome computations and to be able to be used for real-time forecasting. This is especially important in case of emergency, e.g. flash floods. A general state space based formulation of water resources systems is given. It is shown that the general model of runoff control systems is able to handle different kinds of uncertainties. Optimal sequential prediction algorithms for linear discrete time stochastic WR system are presented. In the framework of runoff control the case of optimal stochastic dynamic water quality control is discussed and feedback control policies are established. The algorithms proposed might help the decision maker in working out the optimal operating policies for a large river basin system in the presence of different kinds of uncertainties

Real-Time Forecasting/Control of Water Resource Systems; Selected Papers from an IIASA Workshop, October 18-21,1976

When water resource systems are not under control, the consequences can be devastating. In the United States alone, flood damage cost approximately $1.5 billion annually. These losses can be avoided by building more reservoirs to hold the flood waters, but such construction is very expensive, especially because reservoirs have already been built on the best sites. A better and less expensive alternative is the development of more effective management methods for existing water resource systems, which commonly waste approximately 20 percent of their capacities through mismanagement. Statistical models first appeared in hydrology at the beginning of the 1970s. Hydrologists began to use the techniques of time series analysis and system identification in their models, which seemed to give better results than the earlier, deterministic simulation models. In addition, real-time control of water resources was being developed at the practical level and on-line measurements of rainfall and runoff from a catchment were becoming available. The conceptual models then in use could not take advantage of measurements from the catchment, but on-line measurements now allow an operator to anticipate flood waters upstream or a water shortage downstream. This book contains selected papers from a workshop devoted to the consolidation of international research on statistically estimated models for real-time forecasting and control of water resource systems. The book is divided into three parts. The first part presents several methods of forecasting for water resource systems: distributed lag models, maximum likelihood identification, nonlinear catchment models, Kalman filtering, and self-tuning predictors. The papers in the second part present methods for controlling stream quality and stream flow, and the third part describes forecasting in the United States, the United Kingdom, and Poland

Bacterial microevolution and the Pangenome

The comparison of multiple genome sequences sampled from a bacterial population reveals considerable diversity in both the core and the accessory parts of the pangenome. This diversity can be analysed in terms of microevolutionary events that took place since the genomes shared a common ancestor, especially deletion, duplication, and recombination. We review the basic modelling ingredients used implicitly or explicitly when performing such a pangenome analysis. In particular, we describe a basic neutral phylogenetic framework of bacterial pangenome microevolution, which is not incompatible with evaluating the role of natural selection. We survey the different ways in which pangenome data is summarised in order to be included in microevolutionary models, as well as the main methodological approaches that have been proposed to reconstruct pangenome microevolutionary history

Dissecting the Molecular Mechanism of Nucleotide-Dependent Activation of the KtrAB K+ Transporter

KtrAB belongs to the Trk/Ktr/HKT superfamily of monovalent cation (K+ and Na+) transport proteins that closely resemble K+ channels. These proteins underlie a plethora of cellular functions that are crucial for environmental adaptation in plants, fungi, archaea, and bacteria. The activation mechanism of the Trk/Ktr/HKT proteins remains unknown. It has been shown that ATP stimulates the activity of KtrAB while ADP does not. Here, we present X-ray structural information on the KtrAB complex with bound ADP. A comparison with the KtrAB-ATP structure reveals conformational changes in the ring and in the membrane protein. In combination with a biochemical and functional analysis, we uncover how ligand- dependent changes in the KtrA ring are propagated to the KtrB membrane protein and conclude that, despite their structural similarity, the activation mechanism of KtrAB is markedly different from the activation mechanism of K+ channels