Abstract
We present a nonlinear mathematical model for a low-size and micro-power vibrational energy harvester targeted to power smart prostheses and in particular hip prostheses. Constraints such as available volume, allowable total weight and energy transducer mechanism difficult the development of an optimal generator system, especially considering the low frequencies involved in the human gait. Since non-linear behavior often conducts to better experimental results than those obtained using linear models, a nonlinear model is being pursued to reduce the volume of the generator and maximize performance. By including the non-linear effects of magnetic levitation used to suspend the inertial mass, influence of friction and effects of inductor non-idealities, preliminary results indicate better generator's performance prediction which allows a more effective customization of the energy harvester. (C) 2012 Elsevier Ltd....Selection and/or peer-review under responsibility of the Symposium Cracoviense Sp. z.o.o.

Abstract
Mining data streams poses many challenges to existing Machine Learning algorithms. Algorithms designed to learn in this scenario need to constantly update their decision models in accordance with current data behavior. Therefore, the ability to detect when the behavior of the stream is changing is an important feature of any learning technique approaching data streams. This work is concerned with unsupervised behavior change detection. It suggests the use of density-based clustering and an entropy measurement for change detection that is independent of the number and format of clusters. The proposed approach uses a modified version of the Den Stream algorithm that is designed to better cope with the entropy calculation. Experimental results using synthetic data provide insight on how clustering and novelty detection algorithms can be used for change detection in data streams. © 2012 IEEE.

Abstract
Studies on the impact of foreign direct investment (FDI) on the Chinese economy have essentially focused on the relationship between FDI, productivity and economic growth, revealing a tendency toward sectoral, regional and macroeconomic empirical studies. This work aims to complement these approaches and contribute to the rather limited literature on the relationship between FDI, Human Capital and Innovation at a corporate level. Based on a set of large and innovative firms (national and foreign capital) located in China, we have concluded that (1) the direct impact of foreign capital on the level of human capital in firms is negative, that is no evidence was found suggesting that FDI has a positive influence on their human capital and (ii) in indirect terms, by means of investment in R&D (research and development) activities, FDI has a positive impact on general human capital (i.e. formal education). These results suggest that for China to benefit from FDI, it is necessary to implement a selective policy to attract FDI, taking into account more technologically advanced, R&D-based projects.

Abstract
Renewable energy integration is gradually increasing in several European countries, such as Portugal and Spain, aiming to reduce emissions in power system operations. Particularly, significant investments in hydro energy systems are envisaged in Portugal, representing a secure and reliable energy source towards sustainable development. Additionally, a pool market structure implies that producers should aim at maximizing profits on a day-ahead basis. Usually, hydro power producers have been considered as price-takers, accepting the price signal as input data. Instead, a MILP approach is provided in this paper to determine the operations planning of a hydro producer acting as a price-maker in a day-ahead electricity market. A realistic case study is presented, based on a hydro energy system in cascaded configuration characterized by spatial-temporal interdependency between reservoirs, in order to thoroughly evaluate the expertise of the proposed approach.

Abstract
An incidence matrix approach for mitigating congestion in transmission network is presented in this paper. Based on this methodology, all congested power transmission lines is identified and main economical signals for investment planning is introduced. In this method, we can determine strong and weak transmission corridors in the network. The Flexible AC Transmission System (FACTS) device has been applied to enhance the controllability of power systems. New generations of FACTS device called Distributed FACTS such as distributed series impedance or distributed static series compensator have recently received increasing interests for power system control and are expected to be broadly deployed. This paper presents a detailed formulation and algorithm to find the best location and size of DFACTS to achieve the optimal utilization of transmission capacity to mitigate congestion. This approach can be applied in market simulation and planning owing to its robustness and speed. Unlike, previous admittance based matrix methodologies, which solidly depended on the network topology, independency of network in the presented approach; it would be an effective tool for long-term expansion planning criteria or implementing D-FACTS devices in modern power systems. The simulation results show that the presented method is both satisfactory and consistent with expectation. Simulation results are presented with the PJM 5-bus system to illustrate the capabilities of presented approach in compression with previous works. © Indian Society for Education and Environment (iSee).

Abstract
This paper describes a multi-purpose energy management system that can harvest energy from a multitude of power sources. In order to suffice power needs of a smart hip prosthesis, a prototype was built considering the use of two types of power sources: energy harvesting micro-power generators for intermittent implant electronics powering; wireless energy, by means of an activation system, responsible for, when needed, continuously powering the implant electronics and also configuring its mode of operation. Intermittently or continuously, it is now possible to energize more power demanding systems as the ones that uses a RF transceiver. The smart hip prosthesis can now become a wireless body sensor network node using LR-WPAN protocols such as Bluetooth low energy as is intended in this work. Preliminary results proved that is possible to energize a Bluetooth low energy module, for over 100 s, solely using the stored energy produced by one of the micro-power generators. (C) 2012 Elsevier Ltd....Selection and/or peer-review under responsibility of the Symposium Cracoviense Sp. z.o.o.