Telfor Journal Vol.10 No.1 (2018)

Content

Path Quality Estimator for 802.15.4e TSCH Fast Deployment Tool

J. Vera-Pérez, D. Todolí-Ferrandis, S. Santonja-Climent, J. Silvestre-Blanes, and V. Sempere-Paya
Topic:
Telecommunications Networks
Abstract
This paper introduces a novel quality estimator that uses different metrics to decide the best path towards the root in Wireless Sensor Networks. The different metrics are assessed at medium access control layer (MAC), under the IEEE 802.15.4 standard, and are used at network layer, enhancing the best path selection process done by the routing protocol, and at the application layer, enabling visual quality indicators in the nodes. This quality function is used during deployment stage; ensuring nodes are located optimally and nimbly. This mechanism will help WSN’s adoption in Industrial Internet of Things applications.
Keywords
Deployment, link quality, objective function, WSN.
Full Text
HyperLink Path Quality Estimator for 802.15.4e TSCH Fast Deployment Tool
Page(s)
2-7
Doi
10.5937/telfor1801002V

Two-Phase Load Balancing for Data Center Networks using OpenFlow

N. Maksić
Topic:
Telecommunications Networks
Abstract
This invited paper describes an OpenFlow solution for two-phase load balancing optimized for data center networks. The solution uses aggregate flows and Proxy ARP procedure in order to achieve reduced size of OpenFlow tables, fast flow configuration and compatibility with standard Ethernet networks. The paper presents modification of the proposed solution, based on configuration of interconnected groups of aggregate flows. The paper also discusses the scalability of the solution.
Keywords
OpenFlow, data center, load balancing.
Full Text
HyperLink Two-Phase Load Balancing for Data Center Networks using OpenFlow
Page(s)
8-13
Doi
10.5937/telfor1801008M

Traffic Engineering Approach to Virtual-link Provisioning in Software-defined ISP Networks

S. Tomovic and I. Radusinovic
Topic:
Telecommunications Networks
Abstract
In this paper, we propose a new approach to virtual-link provisioning in ISP (Internet Service Provider) networks. The approach relies on Software Defined Networking (SDN) architecture based on OpenFlow that allows highly granular traffic splitting across multiple paths. The traffic control logic of SDN controller is divided into offline and online component. The online component handles dynamic arrivals of virtual-link requests in accordance with Service Level Agreements (SLAs) requirements. The offline component is responsible for periodic optimization of traffic distribution in the network. In this way, we tend to increase acceptance ratio for virtual-link requests and minimize degradation of best-effort traffic in a scalable manner. Our simulation results show that the proposed method for virtual-link provisioning outperforms solutions that rely on Constrained Shortest Path First (CSPF) and Equal Cost Multi-Path (ECMP) routing.
Keywords
OpenFlow, SDN, traffic engineering, QoS.
Full Text
HyperLink Traffic Engineering Approach to Virtual-link Provisioning in Software-defined ISP Networks
Page(s)
14-19
Doi
10.5937/telfor1801014T

Implementation of ETX Metric within the AODV Protocol in the NS-3 Simulator

N. J. Jevtic and M. Z. Malnar
Topic:
Radio Communications
Abstract
Modern life cannot be imagined without wireless ad hoc networks (WANETs). People use, in a daily manner, smart phones, laptops or tablet computers. With an increasing number of users of WANETs, the need for a fast throughput and small delay is increasing as well. One efficient way to provide users with such demands is to find an optimal route between source and destination node. Therefore, many routing protocols and metrics for WANETs are proposed in last decades. It is very important to test performances of the proposed protocols in various network scenarios. The computer simulation is a very efficient way to test routing protocols and to evaluate their significance and practical value. One of the most recent but very frequently used discrete-event network simulators is Network Simulator 3 (NS-3). In order to contribute to the NS-3 simulator development, an implementation of one of the most commonly used metric in WANET protocols the expected transmission count (ETX) is proposed in this paper. ETX metric is implemented within an ad-hoc on demand distance vector (AODV) protocol. The source code of this implementation is publicly available.
Keywords
wireless ad hoc networks, NS-3, ETX metric, AODV protocol.
Full Text
HyperLink Implementation of ETX Metric within the AODV Protocol in the NS-3 Simulator
Page(s)
20-25
Doi
10.5937/telfor1801020J

Recursive Noise Reduction for Digital Radiography Images

V. S. Ostojić, Đ. S. Starčević, and V. S.Petrović
Topic:
Signal Processing
Abstract
Modern digital radiography images are large, suggesting that a denoising algorithm should be computationally efficient. In this paper, we propose a homomorphic recursive noise reduction approach. The proposed method was compared to anisotropic diffusion on a database consisting of 47 clinical radiography images, and was subjectively deemed better at noise reduction. The proposed approach was shown to require 50 % fewer iterations to produce subjectively the same results. Objective comparison of the algorithms through a structural similarity index and peak signal-to-noise ratio showed that the proposed method outperforms anisotropic diffusion for various signal-to-noise ratios.
Keywords
digital radiography, homomorphic filtering, image noise reduction, recursive filtering.
Full Text
HyperLink Recursive Noise Reduction for Digital Radiography Images
Page(s)
26-31
Doi
10.5937/telfor1801026O

Analysis of the Band-Pass and Notch Filter with Dynamic Damping of Fractional Order Including Discrete Models

M. Bošković, T. B. Šekara, M. R. Rapaić, B. Lutovac, M. Daković, and V. Govedarica
Topic:
Signal Processing
Abstract
The paper presents analysis of the second order band-pass and notch filter with a dynamic damping factor βd of fractional order. Factor βd is given in the form of fractional differentiator of order , i.e. βd=β/s, where β and  are adjustable parameters. The aim of the paper is to exploit an extra degree of freedom of presented filters to achieve the desired filter specifications and obtain a desired response in the frequency and time domain. Shaping of the frequency response enables achieving a better phase response compared to the integer-order counterparts which is of great concern in many applications. For the implementation purpose, the paper presents a comparison of four discretization techniques: the Osutaloup’s Recursive Algorithm (ORA+Tustin), Continued Fractional Expansion (CFE+Tustin), Interpolation of Frequency Characteristic (IFC+Tustin) and recently proposed AutoRegressive with eXogenous input (ARX)-based direct discretization method.
Keywords
Butterworth filter, Discretization, Fractional-order filter, Fractional calculus, Frequency response.
Full Text
HyperLink Analysis of the Band-Pass and Notch Filter with Dynamic Damping of Fractional Order Including Discrete Models
Page(s)
32-37
Doi
10.5937/telfor1801032B

Improving Energy Usage in Energy Harvesting Wireless Sensor Nodes Using Weather Forecast

S. Janković, D. El Mezeni, and L. Saranovac
Topic:
Applied Electronics
Abstract
Battery powered wireless sensor nodes are used in many applications. They can be placed in remote locations and can operate for a long period of time without the need for maintenance. However, finite battery lifetime is one of the main limitations of such devices. Energy harvesting can be used to recharge batteries from environmental energy sources. This enables continuous work when energy neutrality is satisfied. For optimal use of available energy, when energy harvesting is used, the optimization goal switches from energy management to workload maximization while maintaining energy neutrality. In order to achieve energy neutrality, prediction of energy that can be harvested in the future is needed. This prediction can be based on previous measured data. However, this approach can be unreliable when weather conditions change during the day or between days. To improve prediction precision, weather forecast can be used. This information has been used to predict energy that can be harvested in the future but only for the next few hours. We present a two-level predictor that uses cloud cover information from hourly weather forecast for next 24 hour period to predict energy that can be harvested in the same time interval. Proposed predictor achieves a 26% less prediction mean absolute percentage error, a 15% less mean absolute deviation percent error and allows an 8% better performance of simulated wireless sensor node compared to Exponentially Weighted Moving Average (EWMA) predictor.
Keywords
Energy Harvesting, Energy Neutrality, Power Management, Weather Forecast, Wireless Sensor Node.
Full Text
HyperLink Improving Energy Usage in Energy Harvesting Wireless Sensor Nodes Using Weather Forecast
Page(s)
38-43
Doi
10.5937/telfor1801038J

IP Core for Efficient Zero-Run Length Compression of CNN Feature Maps

A. Erdeljan, B. Vukobratović, and R. Struharik
Topic:
Applied Electronics
Abstract
Convolutional Neural Networks (CNNs) are becoming a fundamental tool for machine learning. High performance and energy efficiency are of great importance for deployments of CNNs in many embedded applications. Energy consumption during CNN processing is dominated by memory access and since large networks do not fit in on-chip storage, they require expensive DRAM access. This paper introduces an universal Output Stream Manager (OSM) which can be used to compress and format data coming from a CNN accelerator and reduce external memory access. The OSM exploits the sparsity of data and implements two Zero-Run Length encoding algorithms and can be easily reconfigured to optimize usage for different CNN layers.
Keywords
Convolutional Neural Networks, FPGA, computer vision, zero run-length encoding, Zynq-7000, SystemVerilog.
Full Text
HyperLink IP Core for Efficient Zero-Run Length Compression of CNN Feature Maps
Page(s)
44-49
Doi
10.5937/telfor1801044E

Translation Lookaside Buffer on the 65-nm STG DICE Hardened Elements

V. Ya. Stenin, A. V. Antonyuk, Y. V. Katunin, and P. V. Stepanov
Topic:
Applied Electronics
Abstract
This paper presents the design of hardened translation lookaside buffer based on Spaced Transistor Groups (STG) DICE cells in 65-nm bulk CMOS technology. The resistance to impacts of single nuclear particles is achieved by spacing transistors in two groups together with transistors of the output combinational logic. The elements contain two spaced identical groups of transistors. Charge collection from particle tracks by only transistors of just one of the two groups doesn’t lead to the cell upset. The proposed logical element of matching based on the STG DICE cell for a content-addressable memory was simulated using TCAD tool. The results show the resistance to impacts of single nuclear particles with linear energy transfer (LET) values up to 70 MeV×cm2/mg. Short-term noise pulses in combinational logic of the element can be observed in the range of LET values from 20 to 70 MeV×cm2/mg.
Keywords
content-addressable memory, logical element, memory cell, noise immunity, single nuclear particle, topology.
Full Text
HyperLink Translation Lookaside Buffer on the 65-nm STG DICE Hardened Elements
Page(s)
50-55
Doi
10.5937/telfor1801050S

High Dynamic Range Mapping for Synthetic Aperture Radar Images

A. Gavrovska, I. Reljin, A. Samčović, M. Milivojević, G. Zajić, and V. Starovoitov
Topic:
Multimedia
Abstract
Luminance compression is often performed for high dynamic range images (still images and videos). A nonlinear tone mapping is applied for the compression in order to reproduce high dynamic range images using devices with a more limited (low) dynamic range. The images obtained after mapping may provide significant content differences in comparison to original data. This can be found for both optical and non-optical images. In this paper, we consider non-optical high dynamic range images, such as synthetic aperture radar images. Particularly, luminance compression may produce unwanted effects. Artificial objects found in an image and speckle noise may significantly affect the quality after tone mapping. In this paper, we consider several examples related to synthetic aperture radar images, as well as several global and a local luminance reduction method. The experimental analysis includes a comparison of several quality assessment methods.
Keywords
High dynamic range, synthetic aperture radar, luminance reduction, entropy, image quality.
Full Text
HyperLink High Dynamic Range Mapping for Synthetic Aperture Radar Images
Page(s)
56-61
Doi
10.5937/telfor1801056G

Analysis of Fractional Difference Schemes with Application to Radiographic Images

M. P. Paskaš, B. D. Reljin, and I. S. Reljin
Topic:
Multimedia
Abstract
Visual inspection of radiographic images by radiologists is a regular practice in making a diagnosis. Thus the enhancement of details in radiographs can improve inspection and diagnosis certainty. Through this paper we perform the analysis of the fractional gradient for visual improvement of chest radiographs. Two implementations of the fractional derivative operator, based on central fractional differences, are evaluated. Also we tested two norms for calculation of the magnitude of the fractional gradient, Euclidean and infimum norm, and the conducted tests for both norms are consistent.
Keywords
Fractional calculus, fractional derivative, gradient operators, image enhancement, radiographic images.
Full Text
HyperLink Analysis of Fractional Difference Schemes with Application to Radiographic Images
Page(s)
62-67
Doi
10.5937/telfor1801062P