On machine learning and knowledge organisation in Multimedia Information Retrieval

Recent technological developments have increased the use of machine learning to solve many problems, including many in information retrieval (IR). Deployment of machine-learning techniques is widespread in text search, notability web search engines (Dai et al., 2011). Multimedia information retrieval as a problem however still represents a significant challenge to machine learning as a technological solution, but some problems in IR can still be addressed by using appropriate AI techniques. In this paper we review the technological developments, and provide a perspective on the use of machine-learning techniques in conjunction with knowledge organisation techniques to address multimedia IR needs. We take the perspective from the MacFarlane (2016) position paper, that there are some problems in multimedia IR that AI and machine learning cannot currently solve. The semantic gap in multimedia IR (Enser, 2008) remains a significant problem in the field, and solutions to them are many years off. However, there are occasions where the new technological developments allow the use of knowledge organisation and machine learning in multimedia search systems and services. Specifically we argue that the improvement of detection of some classes of low level features in images (Karpathy and Li, 2015), music (Byrd and Crawford, 2002) and video (Hu et al., 2011) can be used in conjunction with knowledge organisation to tag or label multimedia content for better retrieval performance. We advocate the use of supervised learning techniques. We provide an overview of the use of knowledge organisation schemes in machine learning, and make recommendations to information professionals on the use of this technology with knowledge organisation techniques to solve multimedia IR problems

Combined homotopy and neighboring extremal optimal control

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137623/1/oca2253_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137623/2/oca2253.pd

Selecting and tailoring of images for visual impact in online journalism

Introduction. Images have a strong presence in online journalism and are used to attract readers’ attention to news content. Images are predominantly sourced from online collections offering access to ready imagery. Yet, the literature shows that image retrieval systems fall short of meeting users’ needs. This study investigated image selection and use in online journalism, in order to propose improvements to the effectiveness of image retrieval. Method. Twelve image professionals working in online journalism participated in semi-structured interviews. Eight professionals were observed while performing real illustration tasks in situ. Thematic analysis was used on data to identify common themes. Illustrations created in this study were included in the data, and a social visual semiotics approach was used for the interpretation of visual meaning. Results. A trend in how images were selected and tailored for online news content emerged, and a set of recurring image features was identified in illustrations used for online news content. Conclusions. The primary contribution of this study is the identification of recurring image features and linking them to visual impact. It is expected that when applied as search functionality, these features will improve the effectiveness of retrieval of visually engaging images as required in online journalism

Homogenization and enhancement for the G-equation

We consider the so-called G-equation, a level set Hamilton-Jacobi equation, used as a sharp interface model for flame propagation, perturbed by an oscillatory advection in a spatio-temporal periodic environment. Assuming that the advection has suitably small spatial divergence, we prove that, as the size of the oscillations diminishes, the solutions homogenize (average out) and converge to the solution of an effective anisotropic first-order (spatio-temporal homogeneous) level set equation. Moreover we obtain a rate of convergence and show that, under certain conditions, the averaging enhances the velocity of the underlying front. We also prove that, at scale one, the level sets of the solutions of the oscillatory problem converge, at long times, to the Wulff shape associated with the effective Hamiltonian. Finally we also consider advection depending on position at the integral scale

Relaxation Methods for Mixed-Integer Optimal Control of Partial Differential Equations

We consider integer-restricted optimal control of systems governed by abstract semilinear evolution equations. This includes the problem of optimal control design for certain distributed parameter systems endowed with multiple actuators, where the task is to minimize costs associated with the dynamics of the system by choosing, for each instant in time, one of the actuators together with ordinary controls. We consider relaxation techniques that are already used successfully for mixed-integer optimal control of ordinary differential equations. Our analysis yields sufficient conditions such that the optimal value and the optimal state of the relaxed problem can be approximated with arbitrary precision by a control satisfying the integer restrictions. The results are obtained by semigroup theory methods. The approach is constructive and gives rise to a numerical method. We supplement the analysis with numerical experiments

Cooking as part of a global sustainable food system - a 6 country pilot survey

The cooking of food is a nexus point for multiple issues. Cooking is intertwined with dietary choices, affects the nutrient content and environmental impacts of food, and is linked to time use and gender roles in the home. Due to its intersectionality, changing cooking practices can potentially impact upon multiple Sustainable Development Goals. However, cookery is seldom considered in the wider perspective of a sustainable food system - with only ethnographic studies examining how cooking is performed being the norm. Overall there is a limited evidence base at the population level of how different nations/populations currently cook, and how changing this would result in changes to the environment, consumer health, and economy. The current research aims to create a wider evidence base to demonstrate and quantify why cooking and food practices are important, and how they differ by geography. In this research we piloted a ~40 minute survey using the Qualtrics online survey panel in 6 countries (Nigeria, Ghana, India, Kenya, Brazil, and the UK). Participants were asked a series of questions about their: dietary preferences (e.g. vegetarian, omnivore, etc.), cooking habits (e.g frequency of cooking at home), food preparation (e.g. time taken), cooking methods used (e.g. boil, fry, roast), and perceptions of food waste, food safety, calorie and carbon footprints, as well as food security and demographic questions. 10-15 culturally appropriate/popular foods were accessed through a food frequency questionnaire, containing images of food portion size estimates, from food manuals developed by a research group from the Federal University of Paraná (http://gupea.ufpr.br/?page_id=19; Additional images of bread were sourced from the Food4Me project (DOI: 10.2196/jmir.3105). Figure 1 presents this list of foods. Recruitment used Qualtrics global recruitment services as well the Prolific panel (for the UK). Participants were potentially given financial compensation for taking part by Qualtrics, but this was outside the control of the research team. The surveys were deployed from the 25th of March, 2020. There were slight recruitment issues for some countries due to parts of the survey being carried out in Ramadan and during the COVID-19 lockdown, and so the recruitment window had to be extended until the 1st of June 2020. Participant rates, gender splits (Figure 2) and dietary patterns (figure 3) varied by country. Figure 4 to 10 compare Chicken food habits and perceptions across the 6 countries

Are we ready for sustainable cookery? Comparing current (and future) cooking and time use practices in UK, US and Australia

Cooking practices play a pivotal role in a healthy diet and lifestyle. Cooking is intertwined with dietary choices. To achieve a sustainable food system, we need to change how we cook and prepare food, along with the time we use to prepare and cook food. Cooking practices involve a variety of parameters such as cooking times, method of cooking (e.g. boiling, baking, steaming) and type of appliances (e.g. electric hobs, gas ovens, microwaves), which all influence the nutrition content and energy density of food and result in varying amounts of emitted greenhouse gases. Behavioural cooking choices are driven by factors such as convenience, taste, health and lifestyle and shape certain eating habits, but are also influenced by tradition and transfer of knowledge. This article presents the findings of three pilot surveys deployed in the United Kingdom, United States and Australia in 2019 (n = 385+ for each survey). These surveys asked about cooking and preparation time, methods and equipment for 30 common foods. Though based around similar food cultures, we find differences in cooking practices among the different countries’ populations. We then examine how food choices and cooking practices need to change differently in each country to be in line with current guidance on healthy, sustainable eating such as the guidelines provided by the EAT-Lancet report

How home cooking methods and appliances affect the GHG emissions of food

Food is widely acknowledged as a significant contributor to climate change. Yet, estimates of food-related greenhouse gas emissions frequently consider supply chain stages only up to farm gate or regional distribution centres. Here, we estimate greenhouse gas emissions associated with different cooking methods and appliances in the UK. Data on current cooking practices were collected through a survey with more than 700 respondents. Results reveal that home cooking accounts for as much as 61% of total emissions associated with specific foods, and that this can be substantially reduced through alternative, readily available cooking practices