On a class of optimization-based robust estimators

We consider in this paper the problem of estimating a parameter matrix from observations which are affected by two types of noise components: (i) a sparse noise sequence which, whenever nonzero can have arbitrarily large amplitude (ii) and a dense and bounded noise sequence of "moderate" amount. This is termed a robust regression problem. To tackle it, a quite general optimization-based framework is proposed and analyzed. When only the sparse noise is present, a sufficient bound is derived on the number of nonzero elements in the sparse noise sequence that can be accommodated by the estimator while still returning the true parameter matrix. While almost all the restricted isometry-based bounds from the literature are not verifiable, our bound can be easily computed through solving a convex optimization problem. Moreover, empirical evidence tends to suggest that it is generally tight. If in addition to the sparse noise sequence, the training data are affected by a bounded dense noise, we derive an upper bound on the estimation error.Comment: To appear in IEEE Transactions on Automatic Contro

The role of women in fish processing: handling and marketing in Kainji Lake basin

The study assessed the contribution of women in fish handling, processing and marketing in Kainji Lake basin. Structured questionnaires were administered to three fishing villages selected at random. The fishing villages were Monai, Yuna, Fakun, and New Bussa market. The study revealed that women play vital roles in fisheries activities as producers, assistants to men preservers, traders and financiers. The notable fishing activity performed by women is processing right from the moment the boats or canoes land at sites. Women assist in emptying nets, sorting gutting and cleaning the catch. In most cases their activities involved salting smoking and drying using traditional processing techniques. Women are also involved in storage and marketing of both fresh and smoked fish. In spite of these important contribution, most women in the various fishing communities are illiterates, have little or no say in decision making in areas that affects their livelihood and are regarded as inferior fedex. Culture and religion also has significant impact on their contribution in fishing activitie

Robustness analysis of a Maximum Correntropy framework for linear regression

In this paper we formulate a solution of the robust linear regression problem in a general framework of correntropy maximization. Our formulation yields a unified class of estimators which includes the Gaussian and Laplacian kernel-based correntropy estimators as special cases. An analysis of the robustness properties is then provided. The analysis includes a quantitative characterization of the informativity degree of the regression which is appropriate for studying the stability of the estimator. Using this tool, a sufficient condition is expressed under which the parametric estimation error is shown to be bounded. Explicit expression of the bound is given and discussion on its numerical computation is supplied. For illustration purpose, two special cases are numerically studied.Comment: 10 pages, 5 figures, To appear in Automatic

An atheological argument from evil : a thesis presented in partial fulfillment of the requirements for the degree of Master of Arts in Philosophy at Massey University

Ever since ancient times it has occurred to many people, great and small, that the existence of evil constitutes evidence against that of God. The central claim of this thesis is that, contrary to theistic belief, this evidence is decisive. In the introduction it is argued that all previous attempts to show this fact have been unsuccessful. These attempts have been vitiated by the fallacy of supposing that God, as an all-powerful, all-knowing and all-good agent, is always required to do the best. He is capable of doing. Though other possibilities remain, this supposition usually manifested itself in arguments which claimed that a God of the above mentioned sort cannot exist, because if such a being existed, He would have created a much better world than the actual one. Besides an appeal to God's above mentioned qualities, the sole justification offered for this claim usually has been only to point out the fact that it was in God's power to actualise a better world than the actual one. But this argument is invalid. Given God's qualities, the mere fact that the creation of a better world was an option to God cannot constitute a sufficient reason for Him to take advantage of that option. For, given the fact that there is virtually no limit to what a being like God can do, it is true of any possible world which was in God's power to actualise that He could have created a better one than it. Consequently, if God decided to create, say value, He would have to be quite irrational to decide not to create some particular world just because it was in His power to create a better one than it. For, if He did that, He ultimately would altogether have to forego creating anything at all - which is absurd because it cannot be the case that a being like God is unable to perform His own will. And this is a problem for atheist endeavours because it shows that the claim that if God existed, He would have created a better world than the actual one inevitably remains unsupported if we proceed from this traditional approach. The chief novelty of this thesis lies in showing the way out of this particular difficulty. It is argued here that if God existed, He would have created a better world than the actual one not only because it was in His power to do so, but because the actual world fails to meet a certain adequacy threshold of being good enough for a product of the creative activity of a perfect being like God. The justification offered for this claim relies on a distinction between ends and means. It goes in two steps: Firstly, it is argued that in God's hands the actual world could only be a means to an end. And secondly, it is argued that whatever God's purpose with the actual world might have been, on account of His benevolence it would have to be a morally good one. Consequently, He could have achieved that purpose by creating a world without superfluous, unnecessary evils in it. Failure to do this conflicts with His benevolence. Further, in defence of this last claim it is argued that although God cannot be reasonably required to attempt realizing the best possible moral goal (for nothing qualifies as such), it conflicts with His benevolence if. He fails to employ the best possible moral means available to Him for realizing His goals. The rest of the thesis contains the details and defence of an argument from evil which is advanced within the framework of this new approach

Analysis of A Nonsmooth Optimization Approach to Robust Estimation

In this paper, we consider the problem of identifying a linear map from measurements which are subject to intermittent and arbitarily large errors. This is a fundamental problem in many estimation-related applications such as fault detection, state estimation in lossy networks, hybrid system identification, robust estimation, etc. The problem is hard because it exhibits some intrinsic combinatorial features. Therefore, obtaining an effective solution necessitates relaxations that are both solvable at a reasonable cost and effective in the sense that they can return the true parameter vector. The current paper discusses a nonsmooth convex optimization approach and provides a new analysis of its behavior. In particular, it is shown that under appropriate conditions on the data, an exact estimate can be recovered from data corrupted by a large (even infinite) number of gross errors.Comment: 17 pages, 9 figure

The role of fishermen cooperative societies in the development of fisheries resources on Kainji Lake basin, Nigeria

Field survey was conducted to evaluate the role of fishermen cooperative in the development of fisheries resources in Kainji Lake. The study was conducted with aid of questionnaires administered in five fishing villages namely Monnai, Yuna, Kaya, Malale and Tunga Danbaba. Ten questionnaires were administered in each fishing village majority of the fishermen interviewed are between the ages of 20-40 years. The results of the educational background revealed that 60% of the respondents were knowledgeable only on Quranic education. Majority of the respondents (86%) was members of fishermen cooperative societies. Only 32% of the respondents indicated to have benefited for loan and credit facilities. Sixty-nine (69) percent of fishermen realized income of between N1, 000-N2, and 000 daily. The major problem facing fishermen cooperative includes lack of capital, lack of access to loan and credit facilities, shortage of adequately trained and well-motivated fisheries extension workers, inadequate fishing inputs and high charge of fishing license fees by Kainji Lake fisheries Management and Conservation Unit (KLFMCU). Recommendation was made on how to improve fishermen cooperative for the development of the lake fisheries resource

Optimal control of discrete-time switched linear systems via continuous parameterization

The paper presents a novel method for designing an optimal controller for discrete-time switched linear systems. The problem is formulated as one of computing the discrete mode sequence and the continuous input sequence that jointly minimize a quadratic performance index. State-of-art methods for solving such a control problem suffer in general from a high computational requirement due to the fact that an exponential number of switching sequences must be explored. The method of this paper addresses the challenge of the switching law design by introducing auxiliary continuous input variables and then solving a non-smooth block-sparsity inducing optimization problem.Comment: 6 pages, 2 figures, 2 tables; To appear in the Proceedings of IFAC World Congress, 201

Adaptive output feedback control based on neural networks: application to flexible aircraft control

One of the major challenges in aeronautical flexible structures control is the uncertain for the non stationary feature of the systems. Transport aircrafts are of unceasingly growing size but are made from increasingly light materials so that their motion dynamics present some flexible low frequency modes coupled to rigid modes. For reasons that range from fuel transfer to random flying conditions, the parameters of these planes may be subject to significative variations during a flight. A single control law that would be robust to so large levels of uncertainties is likely to be limited in performance. For that reason, we follow in this work an adaptive control approach. Given an existing closed-loop system where a basic controller controls the rigid body modes, the problem of interest consists in designing an adaptive controller that could deal with the flexible modes of the system in such a way that the performance of the first controller is not deteriorated even in the presence of parameter variations. To this purpose, we follow a similar strategy as in Hovakimyan (2002) where a reference model adaptive control method has been proposed. The basic model of the rigid modes is regarded as a reference model and a neural network based learning algorithm is used to compensate online for the effects of unmodelled dynamics and parameter variations. We then successfully apply this control policy to the control of an Airbus aircraft. This is a very high dimensional dynamical model (about 200 states) whose direct control is obviously hard. However, by applying the aforementioned adaptive control technique to it, some promising simulation results can be achieved