A resource-search and routing algorithm within PCDN autonomy area

This paper studied a new type of network model; it is formed by the dynamic autonomy area, the structured source servers and the proxy servers. The new network model satisfies the dynamics within the autonomy area, where each node undertakes different tasks according to their different abilities, to ensure that each node has the load ability fit its own; it does not need to exchange information via the central servers, so it can carry out the efficient data transmission and routing search. According to the highly dynamics of the autonomy area, we established dynamic tree structure-proliferation system routing and resource-search algorithms and simulated these algorithms. Test results show the performance of the proposed network model and the algorithms are very stable.

A profiling based task scheduling approach for multicore network processors

 Multicore network processors have been playing an increasingly important role in computational processes, which emphasize on scalability and parallelism of the systems, in distributed environments especially in Internet-based delay-sensitive applications. It is an important but unsolved issue, however, to efficiently schedule tasks in network processors with multicore and multithread for improving the system throughput as much as possible. Profiling can gather runtime environment information and guide the compiler to optimize programs through scheduling tasks based on the runtime context. This paper proposes a profiling-based task scheduling approach, targeting on improving the throughput of multicore network processor (Intel IXP) systems in the balanced pipeline way. In this work, we investigate a profiling-based task scheduling framework, a task scheduling algorithm, and a set of performance models. Our task allocation scheme maps tasks onto the pipeline architecture and multiple threads of network processors in parallel, which incorporates the profiling context and global thread refinement. We evaluate our task scheduling algorithm by implementing representative network applications on the Intel IXP network processor. Experimental results demonstrate that our algorithm is able to schedule tasks in a balanced pipeline fashion and achieve the high throughput and data transmission rate. Copyright © 2012 John Wiley & Sons, Ltd.

In support of hydrocarbon exploration and discovery using clouds

Seismic data gathered from the Hydrocarbon Exploration and Discovery Operation is essential to identify possible hydrocarbon existence in a geologically surveyed area. However, the discovery operation takes a long time to be completed and computational processing of the acquired data is often delayed. Hydrocarbon exploration may end up needlessly covering an area without any hydrocarbon traces due to lack of immediate feedback from geophysical experts. This feedback can only be given when the acquired seismic data is computationally processed, analysed and interpreted. In response, we propose a comprehensive model to facilitate Hydrocarbon Exploration and Discovery Operation using encryption, decryption, satellite transmission and clouds. The model details the logical design of Seismic Data Processing (SDP) that exploits clouds and the ability for geophysical experts to provide on-line decisions on how to progress the hydrocarbon exploration operation at a remote location. Initial feasibility assessment was carried out to support our model. The SDP, data encryption and encryption for the assessment were carried out on a private cloud. The assessment shows that the overall process of hydrocarbon exploration from data acquisition, satellite data transmission through to SDP could be executed in a short time and at low costs.

Novel Z-Domain precoding method for blind separation of spatially correlated signals

In this paper, we address the problem of blind separation of spatially correlated signals, which is encountered in some emerging applications, e.g., distributed wireless sensor networks and wireless surveillance systems. We preprocess the source signals in transmitters prior to transmission. Specifically, the source signals are first filtered by a set of properly designed precoders and then the coded signals are transmitted. On the receiving side, the Z-domain features of the precoders are exploited to separate the coded signals, from which the source signals are recovered. Based on the proposed precoders, a closed-form algorithm is derived to estimate the coded signals and the source signals. Unlike traditional blind source separation approaches, the proposed method does not require the source signals to be uncorrelated, sparse, or nonnegative. Compared with the existing precoder-based approach, the new method uses precoders with much lower order, which reduces the delay in data transmission and is easier to implement in practice.

Bloom filter based secure and anonymous DSR protocol in wireless ad hoc networks

Wireless ad hoc networks, especially in the hostile environment, are vulnerable to traffic analysis which allows the adversary to trace the routing messages and the sensitive data packets. Anonymity mechanism in ad hoc networks is a critical securing measure method employed to mitigate these problems. In this paper, we propose a novel secure and anonymous source routing protocol, called SADSR, based on Dynamic Source Routing (DSR) for wireless ad hoc networks. In the proposed scheme, we use the pseudonym, pseudonym based cryptography and the bloom filter to establish secure and anonymous routing in wireless ad hoc networks. Compared to other anonymous routing protocol, SADSR is not only anonymous but also the secure in the routing discover process and data transmission process.

Separating spatially correlated signals using first-order precoders

This paper deals with blind separation of spatially correlated signals mixed by an instantaneous system. Taking advantage of the fact that the source signals are accessible in some man-made systems such as wireless communication systems, we preprocess the source signals in transmitters by a set of properly designed first-order precoders and then the coded signals are transmitted. At the receiving side, information about the precoders are utilized to perform signal separation. Compared with the existing precoder-based methods, the new method only employs the simplest first-order precoders, which reduces the delay in data transmission and is easier to implement in practical applications.

An analytical model for optimal spectrum leasing under constraints of quality of service in CRNs

Cognitive radio improves spectrum efficiency and mitigates spectrum scarcity by allowing cognitive users to opportunistically access idle chunks of the spectrum owned by licensed users. In long-term spectrum leasing markets, secondary network operators make a decision about how much spectrum is optimal to fulfill their users' data transmission requirements. We study this optimization problem in multiple channel scenarios. Under the constrains of expected user admission rate and quality of service, we model the secondary network into a dynamic data transportation system. In this system, the spectrum accesses of both primary users and secondary users are in accordance with stochastic processes, respectively. The main metrics of quality of service we are concerned with include user admission rate, average transmission delay and stability of the delay. To quantify the relationship between spectrum provisioning and quality of service, we propose an approximate analytical model. We use the model to estimate the lower and upper bounds of the optimal amount of the spectrum. The distance between the bounds is relatively narrow. In addition, we design a simple algorithm to compute the optimum by using the bounds. We conduct numerical simulations on a slotted multiple channel dynamic spectrum access network model. Simulation results demonstrate the preciseness of the proposed model. Our work sheds light on the design of game and auction based dynamic spectrum sharing mechanisms in cognitive radio networks.

On the security of compressed sensing-based signal cryptosystem

With the development of the cyber-physical systems (CPS), the security analysis of the data therein becomes more and more important. Recently, due to the advantage of joint encryption and compression for data transmission in CPS, the emerging compressed sensing (CS)-based cryptosystem has attracted much attention, where security is of extreme importance. The existing methods only analyze the security of the plaintext under the assumption that the key is absolutely safe. However, for sparse plaintext, the prior sparsity knowledge of the plaintext could be exploited to partly retrieve the key, and then the plaintext, from the ciphertext. So, the existing methods do not provide a satisfactory security analysis. In this paper, it is conducted in the information theory frame, where the plaintext sparsity feature and the mutual information of the ciphertext, key, and plaintext are involved. In addition, the perfect secrecy criteria (Shannon-sense and Wyner-sense) are extended to measure the security. While the security level is given, the illegal access risk is also discussed. It is shown that the CS-based cryptosystem achieves the extended Wyner-sense perfect secrecy, but when the key is used repeatedly, both the plaintext and the key could be conditionally accessed.

Adoção de tecnologias móveis em empresas do Rio Grande do Norte, Pernambuco e Ceará

One of the best examples of the Information and Communication Technology (ICT) evolutions is on the high capability of storing and processing data into smaller devices, creating a new business condition, the mobility . This mobility in a deeper analysis proposes a business remodeling in many different areas (business segmentations), through the Internet anywhere at any time, allowing managers and researchers to think again their actual models that work nowadays in companies and public institutions, modifying the way internal and external clients can be attended. This thesis analyzes issues on mobile business adoption, technological evolutions and the impacts caused by this new reality the access to information anywhere at any time . This research is exploratory and shows a compilation of similar papers and thesis describing how was conducted the survey within 50 companies in the states of Rio Grande do Norte, Pernambuco and Ceará. The statistics analysis showed the different level of mobile technology usage from simple voice communications to wide band data transmission. The analysis pointed that canonic correlation was the most effective type of analysis to describe the relations among all groups of variables showing which of them are relevant, or not, for mobile technology adoption

Desenvolvimento de um software de comunicação sem fio aplicado à instrumentação de unidade de elevação de petróleo tipo Plunger Lift

This dissertation aims to develop a software applied to a communication system for a wireless sensor network (WSN) for tracking analog and digital variables and control valve of the gas flow in artificial oil s elevation units, Plunger Lift type. The reason for this implementation is due to the fact that, in the studied plant configuration, the sensors communicate with the PLC (Programmable and Logic Controller) by the cables and pipelines, making any changes in that system, such as changing the layout of it, as well as inconveniences that arise from the nature of the site, such as the vicinity s animals presence that tend to destroy the cables for interconnection of sensors to the PLC. For software development, was used communication polling method via SMAC protocol (Simple Medium Access ControlIEEE 802.15.4 standard) in the CodeWarrior environment to which generated a firmware, loaded into the WSN s transceivers, present in the kit MC13193-EVK, (all items described above are owners of Freescale Semiconductors Inc.). The network monitoring and parameterization used in its application, was developed in LabVIEW software from National Instruments. The results were obtained through the observation of the network s behavior of sensors proposal, focusing on aspects such as: indoor and outdoor quantity of packages received and lost, general aspects of reliability in data transmission, coexistence with other types of wireless networks and power consumption under different operating conditions. The results were considered satisfactory, which showed the software efficiency in this communication system

Caracterização numérica de antenas para aplicações RFID utilizando o método das ondas - WCIP

In recent years, the radio frequency identification technology (RFID) has gained great interest both industrial communities as scientific communities. Its ability to locate and monitor objects, animals and persons with active or passive tags allows easy development, with good cost-benefice and still presents undeniable benefits in applications ranging from logistics to healthcare, robotics, security, among others. Within this aspect what else comes excelling are RFID tags and the antennas used in RFID readers. Most tags have antennas omnidirectional and are usually manufactured as dipoles modified printed. The primary purpose of a project of antenna for tag is to achieve the required input impedance to perform a good marriage impedance with the load impedance of the chip. Already the objective principal in project of antennas for readers is to achieve reduced sizes and structures with good data transmission capacity. This work brings the numerical characterization of antennas for RFID applications, being these divided into tags RFID and antennas for RFID readers. Three tags RFID and two antennas for RFID readers, found in literature, are analyzed. The analysis of these structures is made using the Method of Waves - WCIP. Initial results found in the literature are compared with those obtained through simulations in WCIP with objective to show that the Method of Waves is able to analyze such structures. To illustrate the results obtained in simulations is presented the behavior of electric and magnetic fields. It also performed a literature review on the characteristics and principles of RFID technology. Suggestions for continuity to this work are presented

Equalização neural aplicada a sistemas com modulação bidimensional em fibra óptica

Nowadays, optic fiber is one of the most used communication methods, mainly due to the fact that the data transmission rates of those systems exceed all of the other means of digital communication. Despite the great advantage, there are problems that prevent full utilization of the optical channel: by increasing the transmission speed and the distances involved, the data is subjected to non-linear inter symbolic interference caused by the dispersion phenomena in the fiber. Adaptive equalizers can be used to solve this problem, they compensate non-ideal responses of the channel in order to restore the signal that was transmitted. This work proposes an equalizer based on artificial neural networks and evaluates its performance in optical communication systems. The proposal is validated through a simulated optic channel and the comparison with other adaptive equalization techniques

Efeitos da interação dipolar na nucleação de vórtices em nano-cilindros magnéticos

The effect of confinement on the magnetic structure of vortices of dipolar coupled ferromagnetic nanoelements is an issue of current interest, not only for academic reasons, but also for the potential impact in a number of promising applications. Most applications, such as nano-oscillators for wireless data transmission, benefit from the possibility of tailoring the vortex core magnetic pattern. We report a theoretical study of vortex nucleation in pairs of coaxial iron and Permalloy cylinders, with diameters ranging from 21nm to 150nm, and 12nm and 21nm thicknesses, separated by a non-magnetic layer. 12nm thick iron and Permalloy isolated (single) cylinders do not hold a vortex, and 21nm isolated cylinders hold a vortex. Our results indicate that one may tailor the magnetic structure of the vortices, and the relative chirality, by selecting the thickness of the non-magnetic spacer and the values of the cylinders diameters and thicknesses. Also, the dipolar interaction may induce vortex formation in pairs of 12nm thick nanocylinders and inhibit the formation of vortices in pairs of 21nm thick nanocylinders. These new phases are formed according to the value of the distance between the cylinderes. Furthermore, we show that the preparation route may control relative chirality and polarity of the vortex pair. For instance: by saturating a pair of Fe 81nm diameter, 21nm thickness cylinders, along the crystalline anisotropy direction, a pair of 36nm core diameter vortices, with same chirality and polarity is prepared. By saturating along the perpendicular direction, one prepares a 30nm diameter core vortex pair, with opposite chirality and opposite polarity. We also present a theoretical discussion of the impact of vortices on the thermal hysteresis of a pair of interface biased elliptical iron nanoelements, separated by an ultrathin nonmagnetic insulating layer. We have found that iron nanoelements exchange coupled to a noncompensated NiO substrate, display thermal hysteresis at room temperature, well below the iron Curie temperature. The thermal hysteresis consists in different sequences of magnetic states in the heating and cooling branches of a thermal loop, and originates in the thermal reduction of the interface field, and on the rearrangements of the magnetic structure at high temperatures, 5 produce by the strong dipolar coupling. The width of the thermal hysteresis varies from 500 K to 100 K for lateral dimensions of 125 nm x 65 nm and 145 nm x 65 nm. We focus on the thermal effects on two particular states: the antiparallel state, which has, at low temperatures, the interface biased nanoelement with the magnetization aligned with the interface field and the second nanoelement aligned opposite to the interface field; and in the parallel state, which has both nanoelements with the magnetization aligned with the interface field at low temperatures. We show that the dipolar interaction leads to enhanced thermal stability of the antiparallel state, and reduces the thermal stability of the parallel state. These states are the key phases in the application of pairs of ferromagnetic nanoelements, separated by a thin insulating layer, for tunneling magnetic memory cells. We have found that for a pair of 125nm x 65nm nanoelements, separated by 1.1nm, and low temperature interface field strength of 5.88kOe, the low temperature state (T = 100K) consists of a pair of nearly parallel buckle-states. This low temperature phase is kept with minor changes up to T= 249 K when the magnetization is reduced to 50% of the low temperature value due to nucleation of a vortex centered around the middle of the free surface nanoelement. By further increasing the temperature, there is another small change in the magnetization due to vortex motion. Apart from minor changes in the vortex position, the high temperature vortex state remains stable, in the cooling branch, down to low temperatures. We note that wide loop thermal hysteresis may pose limits on the design of tunneling magnetic memory cells

Arquitetura com elevada taxa de processamento e reduzida largura de banda de memória para a estimação de movimento em vídeos digitais

Nowadays several electronics devices support digital videos. Some examples of these devices are cellphones, digital cameras, video cameras and digital televisions. However, raw videos present a huge amount of data, millions of bits, for their representation as the way they were captured. To store them in its primary form it would be necessary a huge amount of disk space and a huge bandwidth to allow the transmission of these data. The video compression becomes essential to make possible information storage and transmission. Motion Estimation is a technique used in the video coder that explores the temporal redundancy present in video sequences to reduce the amount of data necessary to represent the information. This work presents a hardware architecture of a motion estimation module for high resolution videos according to H.264/AVC standard. The H.264/AVC is the most advanced video coder standard, with several new features which allow it to achieve high compression rates. The architecture presented in this work was developed to provide a high data reuse. The data reuse schema adopted reduces the bandwidth required to execute motion estimation. The motion estimation is the task responsible for the largest share of the gains obtained with the H.264/AVC standard so this module is essential for final video coder performance. This work is included in Rede H.264 project which aims to develop Brazilian technology for Brazilian System of Digital Television

Aplicativo informatizado com o nursing activities score: instrumento para gerenciamento da assistência em unidade de terapia intensiva

A gravidade do paciente ou o número de intervenções nem sempre serão proporcionais à carga de trabalho de enfermagem. Este estudo descritivo teve como objetivo demonstrar a trajetória da construção de um aplicativo (software) com o conteúdo do Nursing Activities Score e suas características operacionais. Foi realizado um teste piloto com 12 pacientes seguindo-se a coleta de dados por 90 dias consecutivos em 123 pacientes. Houve compatibilidade na transmissão de dados do Personal Digital Assistent para o computador de mesa, via wireless. A construção do aplicativo resultou em um sistema com coleta e administração de dados e permitiu realizar a interface gráfica. A utilização do aplicativo possibilita o uso de um sistema tecnológico para aplicação diária, com alimentação de um banco de dados sobre as características dos cuidados requeridos. Conhecendo a evolução destas variáveis durante a internação, o enfermeiro poderá planejar, intervir e avaliar a qualidade do cuidado.