A Hierarchical Human-Robot Interaction-Planning Framework for Task Allocation in Collaborative Industrial Assembly Processes

In this paper we propose a framework for task allocation in human-robot collaborative assembly planning. Our framework distinguishes between two main layers of abstraction and allocation. In the higher layer we use an abstract world model, incorporating a multi-agent human-robot team approach in order to describe the collaborative assembly planning problem. From this, nominal coordinated skill sequences for every agent are produced. In order to be able to treat humans and robots as agents of the same form, we move relevant differences/peculiarities into distinct cost functions. The layer beneath handles the concrete skill execution. On atomic level, skills are composed of complex hierarchical and concurrent hybrid state machines, which in turn coordinate the real-time behavior of the robot. Their careful design allows to cope with unpredictable events also on decisional level without having to explicitly plan for them, instead one may rely also on manually designed skills. Such events are likely to happen in dynamic and potentially partially known environments, which is especially true in case of human presence. © 2017 IEEEEU/H2020/688857/E

Transfer Learning for Speech Recognition on a Budget

End-to-end training of automated speech recognition (ASR) systems requires massive data and compute resources. We explore transfer learning based on model adaptation as an approach for training ASR models under constrained GPU memory, throughput and training data. We conduct several systematic experiments adapting a Wav2Letter convolutional neural network originally trained for English ASR to the German language. We show that this technique allows faster training on consumer-grade resources while requiring less training data in order to achieve the same accuracy, thereby lowering the cost of training ASR models in other languages. Model introspection revealed that small adaptations to the network's weights were sufficient for good performance, especially for inner layers.Comment: Accepted for 2nd ACL Workshop on Representation Learning for NL

The social and economic effects of the disability grant for people with disabilities and their households : a qualitative study in KwaZulu-Natal Province.

Thesis (M.A.)-University of KwaZulu-Natal, Durban, 2007.People with disabilities (PWD) face physical and attitudinal barriers to participation in education, the labour market and development processes in general. The social model of disability views this exclusion as disabling and as caused by the way in which society is organised. Combined with the extra costs related to disability, this makes PWD more Vulnerable to poverty, which is exacerbated by the fact that economic and social policies are often seen as being unrelated to each other. In South Africa with its high unemployment and poverty, there is a need for appropriate social assistance for PWD. Currently this is done through a means-tested cash transfer known as the Disability Grant (DG). Yet very little is known about the social and economic effects of the DG. The effects of the state Old Age Pension (OAP) have been well documented regarding, for example, expenditure patterns, utilisation of financial institutions, income-smoothing and household effects. This study aimed to explore whether these effects are similar for DG recipients, including the interaction with disability-related costs and intra-household decision-making processes. It furthermore aimed to explore the relationship between the DG and the labour market. Using qualitative and participatory methods, this study involved people with physical, visual and hearing disabilities who are DG recipients, in eight urban and rural areas of KwaZulu Natal Province. Findings highlighted the complex interactions between the DG recipients, their households, and the physical and attitudinal barriers they face. The grant is primarily used for basic needs (especially food), school expenses, and sometimes water and electricity. It is often consumed in households that have no other or very little income. This means often households remain poor and are vulnerable to financial shocks and debt to cover basic needs. The DG has sometimes contributed to shock mitigation (e.g. through stokvel or funeral policy contributions), but termination of DG for review was in itself a financial shock, necessitating going into debt. The combination of poverty and high unemployment increases reliance on DG by PWD and their household. This interacts with physical and attitudinal barriers and lack of education that hinder PWD from getting employed. Even though some PWD have expressed the desire to work, attempts have been frustrated by barriers faced and because of high general unemployment. This showed that employment of PWD, and possible disincentives to entering employment, must be understood within the current South African context, and that social and economic policies and their effects are inter-related. The research process itself highlighted possible barriers to inclusion of PWD and gives recommendations for more inclusive research processes. The study concludes that while the DG may be one means to inclusion, disability cannot be relegated solely to a social assistance domain. Rather, an intersectoral and 'twin-track' approach IS needed. Intersectoral refers to the collaboration between multiple government departments, private sector and disability organisations. 'Twin-track' refers to the need for programmes and services that are both 'disability targeted' (specific initiatives to empower PWD) and 'disability mainstreamed' (addressing inequalities between disabled and non-disabled people in all general development initiatives). This means that social and economic policies can become more interlinked, and that disability can be integrated into development programmes aimed at addressing poverty and exclusion

A morphological study of the probosces and observations on the feeding habits of fruit-piercing moths

A description is given of how fruit-feeding noctuids pierce fruit and feed on it. The functions and importance of the following feeding movements are discussed: probing with the proboscis, oscillation of the head, to and fro sliding of the galeae an4 the vibration of the proboscis! Two proboscis cleaning processes, using saliva and a labial brush, are described Moths feeding on fruit in orchards were recorded as either feeding on "rotten fruit", "damaged fruit or on "sound fruit". Later experiments with caged moths and morphological studies of their proboscis, showed that the moths recorded under the category "sound fruit" are the so-called piercers while those in the other two categories are the non-piercers. Piercers actually preferred to feed on undamaged fruit. Hourly counts of fruit-feeding noctuids throughout four nights during two seasons revealed that greatest moth activity occurred during the first three hours after dark, followed by a small decrease in numbers around midnight. The numbers increased again at about 01h00 and this number was maintained until 04h00. To determine whether fruit-feeding noctuids return to the same source of food on subsequent nights, moths were caught on the only peach tree that still bore fruit in an orchard in February. On two evenings the following numbers of moths were caught, marked and released: 4 Achaea catella, 84 A. finita, 65 A sordida and 13 Sphingomorpha chlorea. The highest percentage return (7,6%) occurred one day after marking. The longest time lapse between marking and subsequent recording was four days (a single specimen). Tests with caged fruit-feeding moths revealed that there was a clear distinction between moths being able to pierce _the skin of fruit (piercers) as opposed to those that were unable to pierce the skin of even soft ripe fruit (no piercers). For, non-piercers the barriers that prevent them: from feeding on fruit are firstly, the intact skin of the fruit and secondly, the hardness of exposed fruit flesh. A general description of the proboscis of fruit-feeding noctuids is given, followed by a description of the proboscis of individual species. The apical regions of the galeae of nine fruit-feeding moths are figured, namely Achaea finita, dianaris, Calpe provocans, Cyligramma latona, Othreis materna, Parallelia algira, Pericyma atrifusca, Serrodes partita and Sphingomorpha chlorea. Three morphological differences between the proboscis of piercing and non-piercing noctuids exist: 1. the presence of galeal barbs in piercers; 2. the non-tapering proboscis with a wedge-shaped tip of piercers as compared to the gradually tapering proboscis of non-piercers; 3. the very heavily sclerotized and sharply pointed galeal apices of piercers as against the non-piercers' slightly pointed to blunt galeal apices with sclerotization absent or limited to the extreme tip.Dissertation (MSc (Agric))--University of Pretoria, 1976.Animal and Wildlife SciencesMSc (Agric)Unrestricte

Seed bank strategies in a Kalahari ecosystem in relation to grazing and habitats

The seed bank dynamics of five habitats as well as a grazing gradient in the southwestern Kalahari, South Africa were studied. Soil samples were collected in the following habitats: dune crests, dune slopes, dune streets, a calcrete outcrop and a riverbed on the farm Alpha. Soil samples were also collected along a grazing gradient from a watering point. Three methods of soil seed bank analysis were used to analyse the soil samples and to gain insight into soil seed bank response to habitat type and to grazing pressure, over four seasons in the year 2004. Results from the three methods of analysis were also compared to each other. They included the direct seedling germination method, the seedling germination re-examination and the seed extraction method. These analyses were used to (a) estimate seed bank size and composition in response to habitat type and grazing pressure; (b) the differences between the standing vegetation- and the seed bank-flora in different habitats and along a grazing gradient and (c) the type of seed banks that tend to form in certain habitats and in response to grazing pressure. Analyses of soil seed bank size along a grazing gradient showed that the seedling emergence re-examinations estimated a larger size for the seed bank than the direct seedling emergence method. The seed extraction method estimated a significantly larger seed bank size than the other two methods. Heavy grazing pressure favoured annual/opportunistic species such as Schmidtia kalahariensis, which formed very large seed banks in heavily trampled areas. When Schmidtia kalahariensis data was removed from the seed bank analyses, it was found that, in contrast to previous results, the direct germination method mostly estimated a larger seed bank size than the re-examination. Also, the estimation of seed bank size by the flotation method, in this case, was much smaller. The flotation method produced data mostly for hard-seeded species, while the seedling emergence method produced data for species with small seeds and which were readily germinable. In all seasons, the dune crest habitat always had the smallest seed bank and the riverbed habitat always had the largest seed bank. All the dune habitats were characterised by perennial grasses. Perennial grasses formed transient seed banks which were relatively small. The riverbed habitat’s vegetation was mostly composed of annuals. Annual plants formed persistent seed banks which were relatively large. Species richness of the readily germinable seed bank in all habitats, fluctuated between the four seasons and was usually largest in summer. The difference in species richness between the above- and belowground floras fluctuated over four seasons. The dune habitats showed a large difference between the species richness of the above- and the below-ground flora, while the riverbed habitat showed a much smaller difference. The dune habitats had many species with transient seed banks while the riverbed was characterised by many species with short-term persistent and ‘permanent’ seed banks.Dissertation (MSc)--University of Pretoria, 2011.Plant Scienceunrestricte

Joint Goal Human Robot collaboration-From Remembering to Inferring

The ability to infer goals, consequences of one’s own and others’ actions is a critical desirable feature for robots to truly become our companions-thereby opening up applications in several domains. This article proposes the viewpoint that the ability to remember our own past experiences based on present context enables us to infer future consequences of both our actions/goals and observed actions/goals of the other (by analogy). In this context, a biomimetic episodic memory architecture to encode diverse learning experiences of iCub humanoid is presented. The critical feature is that partial cues from the present environment like objects perceived or observed actions of a human triggers a recall of context relevant past experiences thereby enabling the robot to infer rewarding future states and engage in cooperative goal-oriented behaviors. An assembly task jointly done by human and the iCub humanoid is used to illustrate the framework. Link between the proposed framework and emerging results from neurosciences related to shared cortical basis for ‘remembering, imagining and perspective taking’ is discussed

Hydrogels for light delivery in in vivo optogenetic applications

Biocompatible hydrogels present interesting opportunities for in vivo waveguiding for optogenetic or photomedical applications. Here, we investigate the applicability of poly(ethylene glycol) diacrylate hydrogels in combination with scattering particles as optical diffusors. Gel characteristics and bioactivity can be tuned to achieve controlled light distribution and tissue interaction

Gold nanoparticle-mediated laser stimulation causes a complex stress signal in neuronal cells

Gold nanoparticle mediated laser stimulation of neuronal cells allows for cell activation on a single-cell level. It could therefore be considered an alternative to classical electric neurostimulation. The physiological impact of this new approach has not been intensively studied so far. Here, we investigate the targeted cell's reaction to a laser stimulus based on its calcium response. A complex cellular reaction involving multiple sources has been revealed. © 2017 SPIE-OSA