Category Archives: Academia

Machine Learning and Acoustics

As computer systems continue to improve, there is an increased ability to complete tasks using artificial intelligence. A computer system can be trained to perceive its environment, make decisions, and take actions. One of the methods for achieving this is machine learning (ML), where machines ‘learn’ tasks from without the need for explicit programming. Given sufficient training, ML can process large, complex datasets to reveal patterns.

abstract blackboard bulb chalk

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Acoustics is one of the fields generating large amounts of data. For example, every time I deploy a hydrophone in the English Channel, it can record for 3 weeks and return approximately 250 GB of data! It doesn’t take long for the data to quickly add up to an overwhelming amount. Never mind the added challenge of searching through it for sounds of interest, such as fish and vessels. ML could provide the answer, if I could train the computer system to recognise these sounds and search the data for the presence. Similarly, ML could also greatly contribute to other types of acoustic research, like speech processing, sound localisation, noise mitigation, health monitoring, and so on.

But how do young acousticians (yes, I am still counting myself in this category!) learn how to develop and use ML tools? That is where the UK Acoustic Network (UKAN) comes in! The network contains several special interest groups, including one specially devoted to Early Career Researchers that holds an annual Summer School. This year, their aim was to provide training for early career acousticians to get to grips with ML tools. So I joined over 30 scientists at Gregynog Hall in Wales this week for the UKAN Summer School 2019 (#UKANSS19).

The week started with an introduction to Python. This was led by Dr Prasun Ray, a Strategic Teaching Fellow in Applied Mathematics at Imperial College London. Prasun took us through the fundamentals of programming and data analysis in Python, alternating between a mixture of seminars and interactive examples to put us through the paces. Although I haven’t used Python much since 2016, it was good to re-familiarise and get updated on what the software can do!

The ML classes were delivered by Dr Ramon Fuentes (Research Scientist at Callsign Ltd and Visiting Researcher at the University of Sheffield), who has previously applied ML for signal processing and the development of autonomous inspection systems. Although the mathematics of this went whooshing over my biological head, it was still interesting to learn some of the fundamental ideas that ML is built upon. Although anywhere Ramon speaks in the future might want to invest in some additional whiteboards…

Finally, we had a series of lectures on audio and speech applications of ML delivered by Professor Nilesh Madhu from Ghent University. In my opinion, these were the highlight of the week! Nilesh was an excellent speaker, expertly leading us from one topic to another with a strong storyline, a balanced level of detail, plenty of examples, and good humour. His own research focus is on signal detection, analysis and enhancement with application to mobile devices. Despite this seeming fairly different from my own work on the surface, it had a lot of deeper similarities. For example, the problem of recognising and classifying signals in challenging contexts will be particularly relevant to my “Decoding the Deep” project.

As well as generating ideas, the other great thing about this event was meeting people. All too often it is easy to get ‘stuck’ in your own research bubble, only speaking with or working alongside people in the same field. Whilst this can be a good thing, it is still good to step back every so often and look around – because that’s how ideas are born! UKAN exists to support and facilitate networking – and that was a strong highlight of this week. Living with 30+ acousticians for five days means that you never know when an interesting conversation will arise: over the breakfast table; during a lunch break; whilst trying out some casual archery; building a cardboard tower in a competitive team-building exercise; on a hike through the grounds; in a subterranean prison surrounded by the ghosts of past inmates… (not even joking). There were lots of opportunities for networking, bonding, and discussions throughout the week. I think everyone went home with some new contacts and friends, several of which I will be following up with over coming months.

Overall, a successful week for the UKAN Summer School 2019! The ECR Special Interest Group are planning to run another next year, along with some smaller events. Be sure to get in touch to register your interest, propose other events, or join the network!

 

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New paper: Behavioural and acoustical responses of dolphins to vessel traffic and noise

Last night, my sixth (and final) PhD paper was published in the journal Scientific Reports!

In earlier papers, I established that the Swan River is a pretty noisy place.  One of the noisiest sites from an anthropogenic perspective is the Fremantle Inner Harbour, which experiences high levels of vessel traffic.  However, during my initial visual observations I discovered that dolphins continued using the harbour, even though it was a busy noisy environment.  So in this latest paper, I searched for evidence of dolphins responding to boats and noise at a subtler scale.

To do this, I used a combination of visual and acoustic monitoring techniques.  I found that dolphins significantly increased their movement speeds when vessel traffic occurred at high levels.  Similarly, dolphins also changed their behavioural budgets at high vessel densities, spending more time travelling and less time resting or socialising.

I monitored dolphin movement speeds and behaviours, to see how these changed as vessel traffic increased

I also looked for acoustic responses, by measuring nine characteristics to describe the shape and frequencies of dolphin whistles in different noise scenarios.  I found that all nine of these characteristics varied with increasing levels of broadband noise, and that the response was particularly strong for low-frequency noise.

I used nine characteristics to describe dolphin whistles

I’ve spoken before about the importance of scientific publishing, in terms of career brownie points for researchers.  So I’m pretty chuffed to have completed publishing my PhD!  To view the full list of papers from this and other projects, check out my Publications page.  Now to deal with all the ‘leftover’ PhD data that I collected, but didn’t get around to including!

Associate Editor of Austral Ecology

Today I received my first email addressed to “Dear Dr Marley…

And as if that wasn’t enough of a buzz, the email itself was to welcome me onboard as a new Associate Editor for the scientific journal Austral Ecology!

The daunting world of academic publishing…

Most scientific work is published in an academic journal.  The idea is that a piece of work is reviewed by your peers, who can either reject it as unacceptable or recommend it for publication (often after implementing some improvements).  So everything that appears in academic journals has generally been vetted by at least two experts in the field through this ‘peer review’ system. This is to ensure the quality of work being published, as researchers are judged by their publications when applying for jobs and grants.  In some cases, the survival of whole university departments depends on their publication records.

But it’s not just about churning out article after article.  There are thousands of journals out there for different scientific fields, each of which with its own level of prestige.  And your success as a scientist depends on getting your work published in good-quality journals.

Austral Ecology is the official journal of the Ecological Society of Australia (ESA), and is the premier journal of basic and applied ecology in the Southern Hemisphere. This includes experimental, observational or theoretical studies on terrestrial, marine or freshwater systems.  ESA is the main professional association for ecologists in Australia, with over 1,500 members across the country.

The most striking ecological system I’ve ever worked in – the Kimberley of NW Australia

As an Associate Editor, I will be responsible for managing several manuscripts per year.  This involves finding suitable peer reviewers for each article, and making recommendations of the suitability of that article for publication based on the reviews received.

From my own experience, I know that a good editor makes all the difference.  When publishing my first paper, I received excellent support from the journal editor, who guided me through this overwhelmingly daunting process.  I have also received support from an editor in the past when a peer reviewed behaved less-than-professionally when assessing my work.  I believe having a good editor can make all the difference for authors – and I look forward to contributing to this process.