To predict the future wind speed and wind direction is of relevance to the wind industry to maximize the power generation. In this regards, this article describes a methodology for the construction of predictive models based on linear Markov chains under linear algebra point of view. The model analyzes the direction and speed of the wind obtained from a meteorological station. This Model allows making a precise study of wind direction and speeding data; figure out the stability, the most common direction or speed, its behaviour depending on the hours or seasons.
Pessolani, P.; Jara, O.; Gonnet, S.; Cortes, A.; Tinetti, F. IEEE Latin America transactions Vol. 15, num. 11, p. 2152-2163 DOI: 10.1109/TLA.2017.8070421 Data de publicació: 2017-11-01 Article en revista
Resource allocation is a usual problem that must be faced during a distributed system design. Despite the large number of algorithms proposed in literature to solve this problem, most papers lack of detailed descriptions about how to turn these algorithms into real-world reliable protocols. This article presents a fault-tolerant algorithm for distributed resource allocation named SLOTS which is implemented as an executable protocol. It allocates resources among members in a fairly manner using simple heuristics and employing a donation approach. SLOTS supports the dynamic behavior of clusters and provides high availability services. It bases its fault-tolerance properties and membership changes in atomic sets of operations (like transactions) using services provided by an underlying Group Communication System.
Baños, V.; Afaqui, M.; Lopez-Aguilera, E.; Garcia-Villegas, E. IEEE Latin America transactions Vol. 15, num. 9, p. 1621-1628 DOI: 10.1109/TLA.2017.8015044 Data de publicació: 2017-08-23 Article en revista
The most essential part of Internet of Things (IoT) infrastructure is the wireless communication system that acts as a bridge for the delivery of data and control messages. However, the existing wireless technologies lack the ability to support a huge amount of data exchange from many battery driven devices spread over a wide area. In order to support the IoT paradigm, the IEEE 802.11 standard committee is in process of introducing a new standard, called IEEE 802.11ah. This is one of the most promising and appealing standards, which aims to bridge the gap between traditional mobile networks and the demands of the IoT. In this paper, we first discuss the main PHY and MAC layer amendments proposed for IEEE 802.11ah. Furthermore, we investigate the operability of IEEE 802.11ah as a backhaul link to connect devices over a long range. Additionally, we compare the aforementioned standard with previous notable IEEE 802.11 amendments (i.e. IEEE 802.11n and IEEE 802.11ac) in terms of throughput (with and without frame aggregation) by utilizing the most robust modulation schemes. The results show an improved performance of IEEE 802.11ah (in terms of power received at long range while experiencing different packet error rates) as compared to previous IEEE 802.11 standards.
the development of different topologies of power converters with impedance networks have opened up new lines of research, its application in different areas such as transmission systems, high voltage, photovoltaic systems, these have yielded systems with high performance and efficiency, but in recent years its application in research and development of traction systems for electric vehicles have in creased, these topologies can be bidirectional and replace the DC-DC booster used in conventional systems. However, its implementation is necessary to
know the different modulation techniques and control that can be used to reach more efficient traction system and to consolidate these topologies. This article describes the different modulation and control techniques that can be applied to converter topologies with bidirectional impedance networks for applications in traction systems for electric vehicle.
This paper present the design of a cogeneration plant with a Stirling engine, generating electricity using the residual energy as heat of the hot gases from a domestic or industrial furnace outlet. First, the ideal method for calculating the energy needs of hot water of an industrial establishment, taking into account the domestic hot water used in the different devices of the building and the hot water used for heating. Second describes the furnace, to determine the residual heat that will use the Stirling engine to run. In third place is calculated the Stirling engine in accordance with the settings selected and the elements that compose it. Once known operation, the engine is analyzed kinetically and thermodynamically to make their modeling. Finally, technology is analyzed to transform the mechanical energy from Stirling engine into energy that can be used in the building where the installation is implemented. Once created whole process, the calculation of the installation for practical application in a real industrial local becomes, showing the magnitude of the energy obtained and the dimensions of the installation.
The use of impedance networks in different types of DC/DC, DC/AC and AC/AC converters, has increased significantly, and many converters topologies and articles VSI and CSI with impedance networks have been presented for the purpose of overcoming the limitations and problems of voltage and current that frequently occurs in these topologies. The selection and implementation of a topology of network impedance would improve the reliability and performance of the power system. This article presents a study and analysis of different network impedance topologies, the modulation techniques and control for the adapting to power converters for applications in electric traction.
the traction systems for electric vehicles have advanced considerably over recent years, with the application of different topologies of power converters for the control of various types of electric induction motors and permanent magnet. Furthermore, the evolution of power semiconductor elements of Si to SiC wideband have opened up lines of research and development in this area. The trend of manufacturer's traction systems is to reach compact systems where the power dissipation is high and the reduction of losses is minimal, for it the implementation of topologies of converters with SiC devices seems to be a good alternative of use to improve the performance of these systems; This paper describes a study and review of the different types of converter topologies proposed for the development and application in traction systems for electric vehicles. This review will identify the different works presented and analyze their problems, with the aim of seek to optimize these topologies or propose new types of topologies for implementation in traction systems.
Deformable object (e.g., clothes) manipulation by a robot in interaction with a human being presents several interesting challenges. Due to texture and deformability, the object can get hooked in the human limbs. Moreover, the human can change their limbs position and curvature, which require changes in the paths to be followed by the robot. To help solve these problems, in this paper we propose a technique of learning by demonstration able to adapt to changes in position and curvature of the object (human limb) and recover from execution faults (hooks). The technique is tested using simulations, but with data obtained from a real robot
This paper presents the design of a hybrid on-chip VLSI DC/DC converter for low to medium integrated circuit power consumption that combines a switching and a linear regulator in parallel. The main goal is to take the best of both approaches, obtaining good power efficiency as in switching DC/DC converters, with small voltage output ripple as in linear converters. While the switching regulator is used to drive most of the load current, the linear regulator supplies the required current to filter out the steady state ripple due to inductor switching without the need of a filtering output capacitor. In addition, the second regulator supplies the required current when the load changes abruptly and the inductor current is momentarily insufficient. The design has been tested with simulations using a standard 180-nm CMOS technology showing good performance.
Wind turbines are increasingly installed to
generate electricity around the whole, as an alternative energy
source to conventional fossil fuels in order to reduce fossil fuel
energy dependence and environment impact. It is well known
that wind towers must be designed to sustain continuous
vibration forces throughout their operational life, which are
more critical at offshore locations.
The paper aims to analyze the structural stability of a wind
turbine tower made of steel. The wind turbine tower is modeled
as the addition of various (infinitesimal) simplified beamcolumns,
which mathematically can be represented by a switched
system. Each beam-column section is equivalently modeled as a
Hamiltonian system, which allows simplifying the system and
providing the stability general response. An eigenvalue analysis
has been done in order to analyze the stability of the system;
finally, also, some transient simulations of the system are
presented to verify the results obtained.
This paper describes the development of a
computer program using the programing software LabViewTM. This computer program is capable of performing real-time electronic management of a Common Rail Diesel cycle engine. This management is done openly, ie can be varied in real time execution input parameters and thus experience the engine response depending on the variation of these parameters. The computer program is focused on a real-time controller NI CRIO9004 model available from National Instruments Co, which conditions and processes the input signals from several engine sensors and generates output signals to control the various engine actuators. The management of many engine concepts in close loop is performed with the aim of obtaining very precise control of these elements and adaptability to rapid transients.
Rejection of periodic signals has been a subject of great interest in control theory and engineering applications. Periodic disturbances are usually present in mechatronic, hydraulic and electronics systems, between others. This paper proposes a resonant observer-based control for periodic signal rejection. The observer includes, in an embedded way, an internal model of the disturbance that is based on its harmonic decomposition. The resulting disturbance estimation is used by a control law that cancels the periodic disturbance term while controlling a specified tracking task. The proposed scheme lets the control designer to address the disturbance estimation and tracking problems separately. Experimental results, on a mechatronic test bed, show that the proposed resonant observer-based control successfully rejects periodic disturbances.
This article presents a fully-integrated CMOS output-capacitorless low-dropout voltage regulator (LDO). A capacitor multiplier based on a current-mode amplifier is embedded into the error amplifier of the aforementioned LDO to simultaneously enhance the dynamic specifications to load variations, stability by pole splitting, and power saving. The proposed LDO topology is designed and post simulated using a 0.35 mu m CMOS process to deliver a load current between 0-100 mA. The dropout voltage of the LDO is set to 200 mV for 2-3.5 V input voltage. A final benchmark comparison considering all relevant performance metrics is presented.
Continuous monitoring of health state is important in elder and chronically ill (but otherwise not critical) patients. Ideally, the patient should not be aware of being continuously monitored. This study describes an automatic and non-conscious heart rate monitoring system based on the ballistocardiogram (BCG). The bi-axial BCG can be recorded by two piezoelectric force sensors and high-gain amplifiers. Digital signal preprocessing has been implemented to increase the SNR and an algorithm to automatically detect the heart rate has been evaluated. The high gain required makes the system susceptible to forces other than those related to the cardiovascular system, such as those due to body movements. The sensitivity and positive predictive values obtained are 97.8 % and 98.4 % but if the records where the BCG is masked are discarded, the respective values increase to 99.2 % and 99.5 %. These values are comparable to those typically obtained for the ECG.
In case of radiological incidents before to
send a human team to the site would be better have real time
information about the situation that rescue teams can find. In
this paper we simulate an opportunistic network over the nuclear
plant of Ascó, in Tarragona, Spain to provide network
connectivity and resource utilization to the rescue teams
supposing a highly partitioned ad-hoc network. The system
consists of distributed sensors in charge of collecting radiological
data and ground vehicles that are sent to the nuclear plant at the
moment of the accident to sense environmental and radiological
information. Afterwards, data would be analyzed in the control
center. Sensed data would be delivered to a control center using
an Unmanned Aerial Vehicle (UAV) as a carrier. This research
use opportunistically not only communication but also sensing,
storage, etc. We analyze the pair wise contacts involved in our
architecture, as well as visiting times, data collection, capacity of
the links, size of the transmission window of the sensors, etc.
Based on this information, we propose a transmission protocol
with data control. Finally, we implemented an interface through
which the control center can modify the UAV flight plan in order
to get the highest quantity of data from sensors and ground
vehicles and at the same time maximizing the ground sensed
In case of radiological incidents before to
send a human team to the site would be better have real time information about the situation that rescue teams can find. In
this paper we simulate an opportunistic network over the nuclear plant of Ascó, in Tarragona, Spain to provide network connectivity and resource utilization to the rescue teams supposing a highly partitioned ad-hoc network. The system
consists of distributed sensors in charge of collecting radiological data and ground vehicles that are sent to the nuclear plant at the moment of the accident to sense environmental and radiological
information. Afterwards, data would be analyzed in the control center. Sensed data would be delivered to a control center using
an Unmanned Aerial Vehicle (UAV) as a carrier. This research use opportunistically not only communication but also sensing,
storage, etc. We analyze the pair wise contacts involved in our architecture, as well as visiting times, data collection, capacity of the links, size of the transmission window of the sensors, etc. Based on this information, we propose a transmission protocol with data control. Finally, we implemented an interface through which the control center can modify the UAV flight plan in order
to get the highest quantity of data from sensors and ground vehicles and at the same time maximizing the ground sensed
In this paper, we review the workflow of the channel and physical layer modules in VANET simulations and briefly survey some of the most used propagation and packet error models in network simulators for this kind of networks. Through numerical simulations, we compare these propagation models working with a realistic and straightforward packet error model. Our results indicate that there is not a most conservative propagation model and that conservative models vary with the channel capacity. Furthermore, different propagation models specifically designed for VANETs obtain very close results in channels with intermediate capacities.
In the past 30 years, the Electromagnetic Compatibility has established itself as one of the most important quality disciplines, supported by both national and international standards and regulations. The increasing technological development of emerging economies of Latin America and their greater participation in the global market has created the need for continued regulation of their production of electrical and electronic devices. Latin America has a significant potential for economic growth not only as a producer of raw material but also as an exporter and importer of technology and in consequence the Electromagnetic Compatibility has an important role to play. This study shows the current status of the region in terms of regulations, standards and testing facilities relating to electromagnetic compatibility, through a comparison between the four Latin American countries with the largest gross domestic product: Argentina, Brazil, Mexico and Venezuela. Finally, a projection was made on the potential future development of this technological area.
Wireless vehicular communications are a key technology to provide drivers with novel services such as collision avoidance, safety warnings and real-time traffic information. Other services are high-speed toll collection, infotainment and wireless ubiquitous connectivity. It is clear that vehicular communications will be a cornerstone of the future transport systems which will significantly change our daily lives. Vehicular ad hoc networks (VANETs) have rapidly emerged and raised novel research challenges such as the design of network protocols adapted to the specific features of VANETs, e.g. the high speed of vehicles. Also, the design of realistic simulation frameworks is an important goal to speed up the development of VANETs. This paper presents the design and evaluation of GBSR-B, a routing protocol based on GPSR that seeks to improve the performance of VANETs over urban scenarios. Our proposal includes a novel algorithm to select the optimal next-hop forwarding node. This paper also presents an alternative to the perimeter mode used in GPSR. We compare our proposal GBSR-B to GPSR and AODV using the network simulator NCTUns 6.0, showing better results in terms of packet losses.
The aim of this study was to establish the necessary setups for the measurement of the basic parameters of a commercial DTH receiver based on the standardized measurement techniques in order to provide the Venezuelan state a system of quality management to ensure well-functioning of equipment being procured to provide the end user, the digital satellite television service. The tests were done by measuring the variables of interest from the three major subsystems that make DTH system: internal unit, low noise block and the antenna system.
Huerta, M.; Hesselbach, X.; Fabregat, R.; Padilla, J.; Ravelo, O.; Clotet, R. IEEE Latin America transactions Vol. 5, num. 5, p. 352-359 DOI: 10.1109/TLA.2007.4378528 Data de publicació: 2010-11-12 Article en revista
This issue corresponds to the selection of the best papers presented at the XII Conference on Software Engineering and Data Bases, JISBD'2007, held in Zaragoza from the 11th to the 14th of September, 2007.
Since the advent of the first IEEE 802.11 standard, several papers have proposed means of providing QoS to IEEE 802.11 networks and evaluate various traffic-prioritization mechanisms. Nevertheless, studies on the assignment of AIFS times defined in IEEE 802.11e reveal that the various priority levels work in a synchronized manner. The studies show that, under large loads of high-priority traffic, EDCA starves low-priority frames, which is undesirable. We argue that QoS traffic needs to be prioritized, but users sending best-effort frames should also obtain the expected service. High-priority traffic can also suffer performance degradation when using EDCA because of heavy loads of low-priority frames. Thus, we have proposed a mechanism based on desynchronizing the IEEE 802.11e working procedure. It prevents stations that belong to different priority classes from attempting simultaneous transmission, prioritizes independent collision groups and achieves better short-term and long-term channel access fairness. We have evaluated the proposal based on extensive analytical and simulation results. It prevents the strangulation of low-priority traffic, and, moreover, reduces the degradation of high-priority traffic with the increased presence of low-priority frames.