On linear convergence of a distributed dual gradient algorithm for linearly constrained separable convex problems

In this paper we propose a distributed dual gradient algorithm for minimizing linearly constrained separable convex problems and analyze its rate of convergence. In particular, we prove that under the assumption of strong convexity and Lipshitz continuity of the gradient of the primal objective function we have a global error bound type property for the dual problem. Using this error bound property we devise a fully distributed dual gradient scheme, i.e. a gradient scheme based on a weighted step size, for which we derive global linear rate of convergence for both dual and primal suboptimality and for primal feasibility violation. Many real applications, e.g. distributed model predictive control, network utility maximization or optimal power flow, can be posed as linearly constrained separable convex problems for which dual gradient type methods from literature have sublinear convergence rate. In the present paper we prove for the first time that in fact we can achieve linear convergence rate for such algorithms when they are used for solving these applications. Numerical simulations are also provided to confirm our theory.Comment: 14 pages, 4 figures, submitted to Automatica Journal, February 2014. arXiv admin note: substantial text overlap with arXiv:1401.4398. We revised the paper, adding more simulations and checking for typo

Rate analysis of inexact dual first order methods: Application to distributed MPC for network systems

In this paper we propose and analyze two dual methods based on inexact gradient information and averaging that generate approximate primal solutions for smooth convex optimization problems. The complicating constraints are moved into the cost using the Lagrange multipliers. The dual problem is solved by inexact first order methods based on approximate gradients and we prove sublinear rate of convergence for these methods. In particular, we provide, for the first time, estimates on the primal feasibility violation and primal and dual suboptimality of the generated approximate primal and dual solutions. Moreover, we solve approximately the inner problems with a parallel coordinate descent algorithm and we show that it has linear convergence rate. In our analysis we rely on the Lipschitz property of the dual function and inexact dual gradients. Further, we apply these methods to distributed model predictive control for network systems. By tightening the complicating constraints we are also able to ensure the primal feasibility of the approximate solutions generated by the proposed algorithms. We obtain a distributed control strategy that has the following features: state and input constraints are satisfied, stability of the plant is guaranteed, whilst the number of iterations for the suboptimal solution can be precisely determined.Comment: 26 pages, 2 figure

CLINICAL STUDY ON THE INDICATIONS OF PROCEDURES FOR AUGMENTING A LARGE BONE DEFECT, AS A PREPARATION FOR THE INSERTION OF DENTAL IMPLANTS

Most of the time, patients who contact the dentist for the insertion of dental implants have old edentulous areas characterized by marked atrophies. This implies that in these cases, implants of very small size, whose prognosis is not favorable, can be inserted wherever possible. The alternative is the use of bone support surgery. There are several such types of interventions, each addressing a particular clinical situation. Thus, in bone defects of dehiscence or fenestration, interventions such as GBR augmentation may be used. In the case of horizontal defects, GBR, autogenous bone grafting or bone splitting can be used, and in the case of vertical defects, GBR performed at the same time or before implant insertion, or autogenous bone grafting can be used

STUDY ON INTEGRATION OF IMPLANTS INSERTED INTO MAXILLARY GROWTHS AUGMENTED BY SINUS LIFTING INTERVENTIONS

Oral implantology offers the possibility of restoring, through fixed prosthetics, the maxillary arches with loss of lateral teeth. In order to insert implants in these regions, it is often necessary to use interventions that can increase the bone supply, since both the quality and the bone quantity are lower in the respective anatomical areas. It is therefore necessary to use sinus lift, either through the crestal approach or by lateral approach, by making a window in the lateral wall of the maxillary sinus. Each of these approaches has advantages and disadvantages and addresses specific clinical cases, and all of that the clinician needs to know correctly, in order to achieve the expected final results

Energy passivation of a building. The ICSTM building case study

The renewable energy sources are becoming more and more current in the energy supply of buildings, from residential buildings to institutional buildings. The renewable energy sources have proved to be a solution and an important element of the Romanian Energy System. We are starting from the idea of using the renewable sources to passivize a building, and we are relying on existing facilities in the Multidisciplinary Scientific and Technological Research Institute (ICSTM) from Valahia University of Targoviste (UVT) to produce the energy from its own sources. We are also considering the consumption data from previous year as well as the electric link to external power grid. This paper aims to propose new renewable energy units so that ICSTM become energetical independent. Currently, the ICSTM building consumes an amount of energy produced from renewable sources about three times less than that consumed from the external network. In order to determine the number of equipment, specifically CPV (concentrating photovoltaic) panels placed on trackers, it is desirable to create a 40% reserve above the installed power, taking in account the possible future development of the research laboratories

Pervasive Radio Mapping of Industrial Environments Using a Virtual Reality Approach

Wireless communications in industrial environments are seriously affected by reliability and performance issues, due to the multipath nature of obstacles within such environments. Special attention needs to be given to planning a wireless industrial network, so as to find the optimum spatial position for each of the nodes within the network, and especially for key nodes such as gateways or cluster heads. The aim of this paper is to present a pervasive radio mapping system which captures (senses) data regarding the radio spectrum, using low-cost wireless sensor nodes. This data is the input of radio mapping algorithms that generate electromagnetic propagation profiles. Such profiles are used for identifying obstacles within the environment and optimum propagation pathways. With the purpose of further optimizing the radio planning process, the authors propose a novel human-network interaction (HNI) paradigm that uses 3D virtual environments in order to display the radio maps in a natural, easy-to-perceive manner. The results of this approach illustrate its added value to the field of radio resource planning of industrial communication systems

ACCOUNTING ETHICS - RESPONSIBILITY VERSUS CREATIVITY

Professional accountants are ordered in some point in their life to take certain decisions that are ethical or not. Accounting ethics is an important aspect of an accountant's work. In the last decades has increased so much interest in accounting ethics so that the financial statements should be prepared to come to include a descriptive report of accounting professionals who have created and filled these situations. This report should include any information considered relevant about factors that influence ethical behaviour. The present research aims to show what is accounting ethics, what is the purpose of the National Code of Ethics for Professional Accountants of Romania, what is creative accounting and ethical behaviour that depends on an accountant, what are the reasons for the use of creative accounting and also what are its main practices