A comparative study of field-oriented control and direct-torque control of induction motors using an adaptive flux observer

This paper presents a comparative study of field-oriented control (IFOC) and direct-torque control (DTC) of induction motors using an adaptive flux observer. The main characteristics of field-oriented control and direct torque control schemes are studied by simulation, emphasizing their advantages and disadvantages. The performances of the two control schemes are evaluated in terms of torque, current ripples and transient responses to load toque variations. We can nevertheless observe a slight advance of DTC scheme compared to FOC scheme regarding the dynamic flux control performance and the implementation complexity. Consequently, the choice of one or the other scheme will depend mainly on specific requirements of the application

Cyclical Mackey Glass Model for Oil Bull Seasonal

In this article, we propose an innovative way for modelling oil bull seasonals taking into account seasonal speculations in oil markets. Since oil prices behave very seasonally during two periods of the year (summer and winter), we propose a modification of Mackey Glass equation by taking into account the rhythm of seasonal frequencies. Using monthly data for WTI oil prices, Seasonal Cyclical Mackey Glass estimates indicate that seasonal interactions between heterogeneous speculators with different expectations may be responsible for pronounced swings in prices in both periods. Moreover, the seasonal frequency  / 3(referring to a period of 6 months) appears to be persistent over time.Oil bull seasonal, Seasonal speculations, Heterogeneous agents model, Seasonal Cyclical Mackey Glass models.

Defeating ISIS: the Need for a Cooperative Effort

The purpose of this paper is to highlight the importance of a collective approach in the fight against the Islamic State of Iraq and Syria also known as ISIS. The approach of the international community had been doomed to failure because it excluded key players in the region. In order to annihilate this terrorist group and the threat it poses to international security, this article proposes a revision of the approach to the resolution of this problem through the inclusion of all the parties susceptible to secure an efficient contribution to that endeavor before the situation becomes irremediable. In order to do so, the inclusion of Syria and the regional powers is indispensable to for a workable resolution of the conflict. As a result of a theoretical analysis building on realism, rational choice and international terrorism, a proposal to a more inclusive approach to negotiations is recommended. It argues for the imperative to put aside the disagreements concerning the fate of President Assad for the purpose of preventing further chaos regionally and internationally

Beyond multiregional and simple out-of-Africa models of human evolution

info:eu-repo/semantics/publishedVersio

Reducing the Hot Spot Effect in Wireless Sensor Networks with the Use of Mobile Data Sink

The Hot Spot effect is an issue that reduces the network lifetime considerably. The network on the field forms a tree structure in which the sink represents the root and the furthest nodes in the perimeter represent the leaves. Each node collects information from the environment and transmits data packets to a reachable node towards the sink in a multi-hop fashion. The closest nodes to the sink not only transmit their own packets but also the packets that they receive from lower nodes and therefore exhaust their energy reserves and die faster than the rest of the network sensors. We propose a technique to allow the data sink to identify nodes severely suffering from the Hot Spot effect and to move beyond these nodes. We will explore the best trajectory that the data sink should follow. Performance results are presented to support our claim of superiority for our scheme