Transmission loss allocation using artificial neural networks

The introduction of deregulation and subsequent open access policy in electricity sector has brought competition in energy market. Allocation of transmission loss has become a contentious issue among the electricity producers and consumers. A closed form solution for transmission loss allocation does not exist due to the fact that transmission loss is a highly non-linear function of system states and it is a non-separable quantity. In absence of a closed form solution different utilities use different methods for transmission loss allocation. Most of these techniques involve complex mathematical operations and time consuming computations. A new transmission loss allocation tool based on artificial neural network has been developed and presented in this thesis. The proposed artificial neural network computes loss allocation much faster than other methods. A relatively short execution time of the proposed method makes it a suitable candidate for being a part of a real time decision making process. Most independent system variables can be used as inputs to this neural network which in turn makes the loss allocation procedure responsive to practical situations. Moreover, transmission line status (available or failed) was included in neural network inputs to make the proposed network capable of allocating loss even during the failure of a transmission line. The proposed neural networks were utilized to allocate losses in two types of energy transactions: bilateral contracts and power pool operation. Two loss allocation methods were utilized to develop training and testing patterns; the Incremental Load Flow Approach was utilized for loss allocation in the context of bilateral transaction and the Z-bus allocation was utilized in the context of pool operation. The IEEE 24-bus reliability network was utilized to conduct studies and illustrate numerical examples for bilateral transactions and the IEEE 14-bus network was utilized for pool operation. Techniques were developed to expedite the training of the neural networks and to improve the accuracy of results

Adaptive neural network control of discrete-time nonlinear systems

Ph.DDOCTOR OF PHILOSOPH

On the training of feedforward neural networks.

by Hau-san Wong.Thesis (M.Phil.)--Chinese University of Hong Kong, 1993.Includes bibliographical references (leaves [178-183]).Chapter 1 --- INTRODUCTIONChapter 1.1 --- Learning versus Explicit Programming --- p.1-1Chapter 1.2 --- Artificial Neural Networks --- p.1-2Chapter 1.3 --- Learning in ANN --- p.1-3Chapter 1.4 --- Problems of Learning in BP Networks --- p.1-5Chapter 1.5 --- Dynamic Node Architecture for BP Networks --- p.1-7Chapter 1.6 --- Incremental Learning --- p.1-10Chapter 1.7 --- Research Objective and Thesis Organization --- p.1-11Chapter 2 --- THE FEEDFORWARD MULTILAYER NEURAL NETWORKChapter 2.1 --- The Perceptron --- p.2-1Chapter 2.2 --- The Generalization of the Perceptron --- p.2-4Chapter 2.3 --- The Multilayer Feedforward Network --- p.2-5Chapter 3 --- SOLUTIONS TO THE BP LEARNING PROBLEMChapter 3.1 --- Introduction --- p.3-1Chapter 3.2 --- Attempts in the Establishment of a Viable Hidden Representation Model --- p.3-5Chapter 3.3 --- Dynamic Node Creation Algorithms --- p.3-9Chapter 3.4 --- Concluding Remarks --- p.3-15Chapter 4 --- THE GROWTH ALGORITHM FOR NEURAL NETWORKSChapter 4.1 --- Introduction --- p.4-2Chapter 4.2 --- The Radial Basis Function --- p.4-6Chapter 4.3 --- The Additional Input Node and the Modified Nonlinearity --- p.4-9Chapter 4.4 --- The Initialization of the New Hidden Node --- p.4-11Chapter 4.5 --- Initialization of the First Node --- p.4-15Chapter 4.6 --- Practical Considerations for the Growth Algorithm --- p.4-18Chapter 4.7 --- The Convergence Proof for the Growth Algorithm --- p.4-20Chapter 4.8 --- The Flow of the Growth Algorithm --- p.4-21Chapter 4.9 --- Experimental Results and Performance Analysis --- p.4-21Chapter 4.10 --- Concluding Remarks --- p.4-33Chapter 5 --- KNOWLEDGE REPRESENTATION IN NEURAL NETWORKSChapter 5.1 --- An Alternative Perspective to Knowledge Representation in Neural Network: The Temporal Vector (T-Vector) Approach --- p.5-1Chapter 5.2 --- Prior Research Works in the T-Vector Approach --- p.5-2Chapter 5.3 --- Formulation of the T-Vector Approach --- p.5-3Chapter 5.4 --- Relation of the Hidden T-Vectors to the Output T-Vectors --- p.5-6Chapter 5.5 --- Relation of the Hidden T-Vectors to the Input T-Vectors --- p.5-10Chapter 5.6 --- An Inspiration for a New Training Algorithm from the Current Model --- p.5-12Chapter 6 --- THE DETERMINISTIC TRAINING ALGORITHM FOR NEURAL NETWORKSChapter 6.1 --- Introduction --- p.6-1Chapter 6.2 --- The Linear Independency Requirement for the Hidden T-Vectors --- p.6-3Chapter 6.3 --- Inspiration of the Current Work from the Barmann T-Vector Model --- p.6-5Chapter 6.4 --- General Framework of Dynamic Node Creation Algorithm --- p.6-10Chapter 6.5 --- The Deterministic Initialization Scheme for the New Hidden NodesChapter 6.5.1 --- Introduction --- p.6-12Chapter 6.5.2 --- Determination of the Target T-VectorChapter 6.5.2.1 --- Introduction --- p.6-15Chapter 6.5.2.2 --- Modelling of the Target Vector βQhQ --- p.6-16Chapter 6.5.2.3 --- Near-Linearity Condition for the Sigmoid Function --- p.6-18Chapter 6.5.3 --- Preparation for the BP Fine-Tuning Process --- p.6-24Chapter 6.5.4 --- Determination of the Target Hidden T-Vector --- p.6-28Chapter 6.5.5 --- Determination of the Hidden Weights --- p.6-29Chapter 6.5.6 --- Determination of the Output Weights --- p.6-30Chapter 6.6 --- Linear Independency Assurance for the New Hidden T-Vector --- p.6-30Chapter 6.7 --- Extension to the Multi-Output Case --- p.6-32Chapter 6.8 --- Convergence Proof for the Deterministic Algorithm --- p.6-35Chapter 6.9 --- The Flow of the Deterministic Dynamic Node Creation Algorithm --- p.6-36Chapter 6.10 --- Experimental Results and Performance Analysis --- p.6-36Chapter 6.11 --- Concluding Remarks --- p.6-50Chapter 7 --- THE GENERALIZATION MEASURE MONITORING SCHEMEChapter 7.1 --- The Problem of Generalization for Neural Networks --- p.7-1Chapter 7.2 --- Prior Attempts in Solving the Generalization Problem --- p.7-2Chapter 7.3 --- The Generalization Measure --- p.7-4Chapter 7.4 --- The Adoption of the Generalization Measure to the Deterministic Algorithm --- p.7-5Chapter 7.5 --- Monitoring of the Generalization Measure --- p.7-6Chapter 7.6 --- Correspondence between the Generalization Measure and the Generalization Capability of the Network --- p.7-8Chapter 7.7 --- Experimental Results and Performance Analysis --- p.7-12Chapter 7.8 --- Concluding Remarks --- p.7-16Chapter 8 --- THE ESTIMATION OF THE INITIAL HIDDEN LAYER SIZEChapter 8.1 --- The Need for an Initial Hidden Layer Size Estimation --- p.8-1Chapter 8.2 --- The Initial Hidden Layer Estimation Scheme --- p.8-2Chapter 8.3 --- The Extension of the Estimation Procedure to the Multi-Output Network --- p.8-6Chapter 8.4 --- Experimental Results and Performance Analysis --- p.8-6Chapter 8.5 --- Concluding Remarks --- p.8-16Chapter 9 --- CONCLUSIONChapter 9.1 --- Contributions --- p.9-1Chapter 9.2 --- Suggestions for Further Research --- p.9-3REFERENCES --- p.R-1APPENDIX --- p.A-

Études des systèmes de communications sans-fil dans un environnement rural difficile

Les systèmes de communication sans fil, ayant de nombreux avantages pour les zones rurales, peuvent aider la population à bien s'y établir au lieu de déménager vers les centres urbains, accentuant ainsi les problèmes d’embouteillage, de pollution et d’habitation. Pour une planification et un déploiement efficace de ces systèmes, l'atténuation du signal radio et la réussite des liens d’accès doivent être envisagées. Ce travail s’intéresse à la provision d’accès Internet sans fil dans le contexte rural canadien caractérisé par sa végétation dense et ses variations climatiques extrêmes vu que les solutions existantes sont plus concentrées sur les zones urbaines. Pour cela, nous étudions plusieurs cas d’environnements difficiles affectant les performances des systèmes de communication. Ensuite, nous comparons les systèmes de communication sans fil les plus connus. Le réseau sans fil fixe utilisant le Wi-Fi ayant l’option de longue portée est choisi pour fournir les communications aux zones rurales. De plus, nous évaluons l'atténuation du signal radio, car les modèles existants sont conçus, en majorité, pour les technologies mobiles en zones urbaines. Puis, nous concevons un nouveau modèle empirique pour les pertes de propagation. Des approches utilisant l’apprentissage automatique sont ensuite proposées, afin de prédire le succès des liens sans fil, d’optimiser le choix des points d'accès et d’établir les limites de validité des paramètres des liens sans fil fiables. Les solutions proposées font preuve de précision (jusqu’à 94 % et 8 dB RMSE) et de simplicité, tout en considérant une multitude de paramètres difficiles à prendre en compte tous ensemble avec les solutions classiques existantes. Les approches proposées requièrent des données fiables qui sont généralement difficiles à acquérir. Dans notre cas, les données de DIGICOM, un fournisseur Internet sans fil en zone rurale canadien, sont utilisées. Wireless communication systems have many advantages for rural areas, as they can help people settle comfortably and conveniently in these regions instead of relocating to urban centers causing various overcrowding, habitation, and pollution problems. For effective planning and deployment of these technologies, the attenuation of the radio signal and the success of radio links must be precisely predicted. This work examines the provision of wireless internet access in the Canadian rural context, characterized by its dense vegetation and its extreme climatic variations, since existing solutions are more focused on urban areas. Hence, we study several cases of difficult environments affecting the performances of communication systems. Then, we compare the best-known wireless communication systems. The fixed wireless network using Wi-Fi, having the long-range option, is chosen to provide wireless access to rural areas. Moreover, we evaluate the attenuation of the radio signal, since the existing path loss models are generally designed for mobile technologies in urban areas. Then, we design a new path loss empirical model. Several approaches are then proposed by using machine learning to predict the success of wireless links, optimize the choice of access points and establish the validity limits for the pertinent parameters of reliable wireless connections. The proposed solutions are characterized by their accuracy (up to 94% and 8 dB RMSE) and simplicity while considering a wide range of parameters that are difficult to consider all together with conventional solutions. These approaches require reliable data, which is generally difficult to acquire. In our case, the dataset from DIGICOM, a rural Canadian wireless internet service provider, is used