Analysis of template-based detection algorithms for inshore Bryde’s whale short pulse calls

CITATION: Ogundile, O. O. & Versfeld, D. J. J. 2020. Analysis of template-based detection algorithms for inshore Bryde’s whale short pulse calls. IEEE Access, 8:14377-14385, doi:10.1109/ACCESS.2020.2966254.The original publication is available at https://ieeexplore.ieee.orgMarine mammals use sound for communication and echolocation within their ecosystems. The detection of these sounds is an important aspect of signal processing, such that we can estimate the spatial position and direction of arrival of these mammals, and have an understanding of their ecology. Passive acoustic monitoring (PAM) is widely used to understand marine mammal movement and vocal repertoire. In PAM, datasets are accumulated over days, months or years. Thus, it is impracticable to manually analyse the datasets because it is very large. This motivated the development of automated sound detection techniques for marine mammals, which most often varies depending on the vocal duration, frequency range and call type. In this paper, continuous recordings of Bryde’s whale ( Balaenoptera edeni edeni ) short pulse calls (< 3.1s long) were collected on a weekly basis from December 2018 to April 2019 on sighting of the individual in a single site in the endmost South-West of South Africa. The sound, previously not documented off South Africa, was observed on visual confirmation of the presence of inshore Brydes’s whale. In addition, the paper develops and analyses two automated template-based detection algorithms for this short pulse call, employing dynamic time warping (DTW) and linear predictive coding (LPC) techniques. These proposed template-based detectors are novel, as they have not being previously used in Bryde’s whale sound detection in the literature. When applied to the continuous recordings of the short pulse calls, the DTW-based and LPC-based detection algorithms obtained a sensitivity of 96.04% and 97.14% respectively for high signal-to-noise ratio (about 10dB above the ambient sound). Otherwise, for low SNR, the DTW-based and LPC-based detection algorithms obtained a sensitivity of 94.98% and 96.00% respectively. These detection algorithms exhibit low computational time complexity and can be modified to analyse the movement of obscure but vocal marine species instead of manual identification.https://ieeexplore.ieee.org/document/8957435Publisher's versio

A survey on an energy-efficient and energy-balanced routing protocol for wireless sensor networks

Wireless sensor networks (WSNs) form an important part of industrial application. There has been growing interest in the potential use of WSNs in applications such as environment monitoring, disaster management, health care monitoring, intelligence surveillance and defence reconnaissance. In these applications, the sensor nodes (SNs) are envisaged to be deployed in sizeable numbers in an outlying area, and it is quite difficult to replace these SNs after complete deployment in many scenarios. Therefore, as SNs are predominantly battery powered devices, the energy consumption of the nodes must be properly managed in order to prolong the network lifetime and functionality to a rational time. Different energy-efficient and energy-balanced routing protocols have been proposed in literature over the years. The energy-efficient routing protocols strive to increase the network lifetime by minimizing the energy consumption in each SN. On the other hand, the energy-balanced routing protocols protract the network lifetime by uniformly balancing the energy consumption among the nodes in the network. There have been various survey papers put forward by researchers to review the performance and classify the different energy-efficient routing protocols for WSNs. However, there seems to be no clear survey emphasizing the importance, concepts, and principles of load-balanced energy routing protocols for WSNs. In this paper, we provide a clear picture of both the energy-efficient and energy-balanced routing protocols for WSNs. More importantly, this paper presents an extensive survey of the different state-of-the-art energy-efficient and energy-balanced routing protocols. A taxonomy is introduced in this paper to classify the surveyed energy-efficient and energy-balanced routing protocols based on their proposed mode of communication towards the base station (BS). In addition, we classified these routing protocols based on the solution types or algorithms, and the input decision variables defined in the routing algorithm. The strengths and weaknesses of the choice of the decision variables used in the design of these energy-efficient and energy-balanced routing protocols are emphasised. Finally, we suggest possible research directions in order to optimize the energy consumption in sensor networks.The Advanced Sensor Networks SARChI Chair program, co-hosted by University of Pretoria (UP) and Council for Scientific and Industrial Research (CSIR), through the National Research Foundation (NRF) of South Africa.http://www.mdpi.com/journal/sensorsam2017Electrical, Electronic and Computer Engineerin

Review of automatic detection and classification techniques for cetacean vocalization

CITATION: Usman, A. M., Ogundile, O. O. & Versfeld, D. J. J. 2020. Review of automatic detection and classification techniques for cetacean vocalization. IEEE Access, 8:105181-105206, doi:10.1109/ACCESS.2020.3000477.The original publication is available at https://ieeexplore.ieee.orgPublication of this article was funded by the Stellenbosch University Open Access FundENGLISH ABSTRACT: Cetaceans have elicited the attention of researchers in recent decades due to their importance to the ecosystem and their economic values. They use sound for communication, echolocation and other social activities. Their sounds are highly non-stationary, transitory and range from short to long sounds. Passive acoustic monitoring (PAM) is a popular method used for monitoring cetaceans in their ecosystems. The volumes of data accumulated using PAM are usually big, so they are difficult to analyze using manual inspection. Therefore different techniques with mixed outcomes have been developed for the automatic detection and classification of signals of different cetacean species. So far, no single technique developed is perfect to detect and classify the vocalizations of over 82 known species due to variability in time-frequency, difference in the amplitude among species and within species' vocal repertoire, physical environment, among others. The accuracy of any detector or classifier depends on the technique adopted as well as the nature of the signal to be analyzed. In this article, we review the existing techniques for the automatic detection and classification of cetacean vocalizations. We categorize the surveyed techniques, while emphasizing the advantages and disadvantages of these techniques. The article suggests possible research directions that can improve existing detection and classification techniques. In addition, the article recommends other suitable techniques that can be used to analyze non-linear and non-stationary signals such as the cetaceans' signals. Several research have been dedicated to this topic, however, there is no review of these past results that gives a quick overview in the area of cetacean detection and classification. This review will help researchers and practitioners in the field to make insightful decisions based on their requirements.https://ieeexplore.ieee.org/document/9110497/authors#authorsPublisher's versio

Evaluating DoS jamming attack on reactive routing protocol in wireless sensor networks

Wireless sensor networks (WSNs) over the years have emerged as the enabling underlining infrastructure for new wireless technology trends such as Internet-of Things (IoT) and Fog Computing. Its application has spread across diverse fields such as agriculture, military, healthcare and home automation. Despite its promising attributes, it is characterized by its extremely limited resources such as battery energy and memory. Additionally, its deployment in hostile and unattended areas make it vulnerable to security attacks. One of such attacks is the denial of service (DoS) jamming attack that is perpetrated by malicious nodes emitting radio frequency signals to disrupt and interfere with the normal functions of the sensor nodes in the network. This eventually causes a denial of service in the network. Different routing protocols have been proposed over the years to guarantee reliable communication and maintain the network lifetime and functionality for a reasonable duration, notwithstanding DoS jamming attack. Therefore, in this work, we evaluate the effect of a constant jamming DoS attack on two key reactive routing protocols in WSN, ad hoc on-demand distance vector (AODV) and dynamic source routing (DSR). Metrics such as packet sending ratio (PSR), packet loss (PL) and transmitted packets are used to measure the impact of constant jamming DoS attack in the network. Simulation results using network simulation 2 (NS2) and trace graph show that, irrespective of the adopted reactive routing protocol, the impact of the jamming attack is the same

Review of channel estimation for candidate waveforms of next generation networks

Abstract: The advancement in wireless communication applications encourages the use of effective and efficient channel estimation (CE) techniques because of the varying behaviour of the Rayleigh fading channel. In most cases, the emphasis of most proposed CE schemes is to improve the CE performance and complexity for ensuring quality signal reception and improved system throughput. Candidate waveforms whose designs are based on filter bank multi-carrier (FBMC) modulation techniques such as filter bank orthogonal frequency division multiplexing based on offset quadrature amplitude modulation (OFDM-OQAM), universal filtered multicarrier (UFMC) and generalised frequency division multiplexing based on offset quadrature amplitude modulation (GFDM-OQAM) are no exception to the use of these proposed CE techniques in the literature. These schemes are considered as potential waveform candidates for the physical/media access control layer of the emerging fifth generation (5G) networks. Therefore, pinpoint CE techniques represent an important requirement for these waveforms to attain their full potentials. In this regard, this paper reviews the concept of CE as applicable to these waveforms as well as other waveform candidates under consideration in the emerging 5G networks. Since the design of the majority of the waveform candidates is filter based, a review of the general filter design considerations is presented in this paper. Secondly, we review general CE techniques for candidate waveforms of next generation networks and classify some of the studied CE techniques. In particular, we classify the CE schemes used in filter bank OFDM-OQAM and GFDM-OQAM based transceivers and present a performance comparison of some of these CE schemes. Besides, the paper reviews the performances of two linear CE schemes and three adaptive based CE schemes for two FBMC based waveform candidates assuming near perfect reconstruction (NPR) and non-perfect reconstruction (Non-PR) filter designs over slow and fast frequency selective Rayleigh fading channels. The results obtained are documented through computer simulations, where the performances of the studied CE schemes in terms of the normalised mean square error (NMSE) are analysed. Lastly, we summarise the findings of this work and suggest possible research directions in order to improve the potentials of the studied candidate waveforms over Rayleigh fading channels

Review of channel estimation for candidate waveforms of next generation networks

Abstract: The advancement in wireless communication applications encourages the use of effective 2 and efficient channel estimation (CE) techniques because of the varying behaviour of the Rayleigh 3 fading channel. In most cases, the emphasis of most proposed CE schemes is to improve the CE 4 performance and complexity for ensuring quality signal reception and improved system throughput. 5 Candidate waveforms whose designs are based on filter bank multi-carrier (FBMC) modulation 6 techniques such as filter bank orthogonal frequency division multiplexing based on offset quadrature 7 amplitude modulation (OFDM-OQAM), universal filtered multicarrier (UFMC) and generalised 8 frequency division multiplexing based on offset quadrature amplitude modulation (GFDM-OQAM) 9 are no exception to the use of these proposed CE techniques in the literature. These schemes are 10 considered as potential waveform candidates for the physical/media access control layer of the 11 emerging fifth generation (5G) networks. Therefore, pinpoint CE techniques represent an important 12 requirement for these waveforms to attain their full potentials. In this regard, this paper reviews 13 the concept of CE as applicable to these waveforms as well as other waveform candidates under 14 consideration in the emerging 5G networks. Since the design of the majority of the wavefor

Review of channel estimation for candidate waveforms of next generation networks

CITATION: Ijiga, O. E., et al. 2019. Review of channel estimation for candidate waveforms of next generation networks. Electronics, 8(9):956, doi:10.3390/electronics8090956.The original publication is available at https://www.mdpi.comPublication of this article was funded by the Stellenbosch University Open Access FundENGLISH ABSTRACT: The advancement in wireless communication applications encourages the use of effective and efficient channel estimation (CE) techniques because of the varying behaviour of the Rayleigh fading channel. In most cases, the emphasis of most proposed CE schemes is to improve the CE performance and complexity for ensuring quality signal reception and improved system throughput. Candidate waveforms whose designs are based on filter bank multi-carrier (FBMC) modulation techniques such as filter bank orthogonal frequency division multiplexing based on offset quadrature amplitude modulation (OFDM-OQAM), universal filtered multicarrier (UFMC) and generalised frequency division multiplexing based on offset quadrature amplitude modulation (GFDM-OQAM) are no exception to the use of these proposed CE techniques in the literature. These schemes are considered as potential waveform candidates for the physical/media access control layer of the emerging fifth generation (5G) networks. Therefore, pinpoint CE techniques represent an important requirement for these waveforms to attain their full potentials. In this regard, this paper reviews the concept of CE as applicable to these waveforms as well as other waveform candidates under consideration in the emerging 5G networks. Since the design of the majority of the waveform candidates is filter based, a review of the general filter design considerations is presented in this paper. Secondly, we review general CE techniques for candidate waveforms of next generation networks and classify some of the studied CE techniques. In particular, we classify the CE schemes used in filter bank OFDM-OQAM and GFDM-OQAM based transceivers and present a performance comparison of some of these CE schemes. Besides, the paper reviews the performances of two linear CE schemes and three adaptive based CE schemes for two FBMC based waveform candidates assuming near perfect reconstruction (NPR) and non-perfect reconstruction (Non-PR) filter designs over slow and fast frequency selective Rayleigh fading channels. The results obtained are documented through computer simulations, where the performances of the studied CE schemes in terms of the normalised mean square error (NMSE) are analysed. Lastly, we summarise the findings of this work and suggest possible research directions in order to improve the potentials of the studied candidate waveforms over Rayleigh fading channels.https://www.mdpi.com/2079-9292/8/9/956#metricsPublisher's versio