Active Audition for Robots using Parameter-Less Self-Organising Maps

How can a robot become aware of its surroundings? How does it create its own subjective, inner representation of the real world, so that relationships in the one are reflected in the other? It is well known that structures analogous to Self-Organising Maps (SOM) are involved with this task in animals, and this thesis undertakes to explore if and how a similar approach can be success- fully applied in robotics. In order to study the environment-to-abstraction mapping with a minimum of guidance from directed learning and built-in design assumptions, this thesis examines the active audition task in which a system must determine the direction of a sound source and orient towards it, both in horizontal and vertical direction. Previous explanations of directional hearing in animals, and the implementation of directional hearing algorithms in robots have tended to focus on the two best known directional clues; the intensity and time differences. This thesis hypothesises that it is advantageous to use a synergy of a wider range of metrics, namely the phase and relative intensity difference. A solution to the active audition problem is proposed based on the Parameter- Less Self-Organising Map (PLSOM), a new algorithm also introduced in this thesis. The PLSOM is used to extract patterns from a high-dimensional input space to a low-dimensional output space. In this application the output space is mapped to the correct motor command for turning towards the source and focusing attention on the selected source by filtering unwanted noise. The dimension-reducing capability of the PLSOM enables the use of more than just two directional clues for computation of the direction. This thesis presents the new PLSOM algorithm for SOM training and quantifies its performance relative to the ordinary SOM algorithm. The mathematical correctness of the PLSOM is demonstrated and the properties and some applications of this new algorithm are examined, notably in automatically modelling a robot's surroundings in a functional form: Inverse Kinematics (IK). The IK problem is related in principle to the active audition problem - functional rather than abstract representation of reality - but raises some new questions of how to use this internal representation in planning and execution of movements. The PLSOM is also applied to classification of high-dimensional data and model-free chaotic time series prediction. A variant of Reinforcement Learning based on Q-Learning is devised and tested. This variant solves some problems related to stochastic reward functions. A mathematical proof of correct state-action pairing is devised

Pedal dermatophyte infection in psoriasis.

Background Dermatophyte infections have been considered rare in psoriasis. However, there are data indicating that tinea unguium is as common or even more common in psoriasis compared with healthy controls. Tinea unguium is generally a secondary event to tinea pedis infection. Objectives To study the prevalence of tinea pedis and tinea unguium in psoriasis compared with a control group. Methods Consecutive psoriasis outpatients aged 18-64 years attending a department of dermatology were examined. Samples for direct microscopy and culture were taken from the interdigital spaces, soles and toenails. Consecutive patients without signs of psoriasis or atopic dermatitis seeking examination of moles constituted the control group. Results In total, 239 patients with psoriasis and 245 control patients were studied. The prevalence of tinea pedis was 8·8%[95% confidence interval (CI) ± 3·6%] in the psoriasis group and 7·8% (95% CI ± 3·4%) in the control group. The corresponding figures for prevalence of tinea unguium were 4·6% (95% CI ± 2·7%) and 2·4% (95% CI ± 1·9%), respectively. The differences found in the psoriasis vs. the control groups were not statistically significant. Conclusions This study does not support the hypothesis that the prevalence of tinea pedis and tinea unguium in patients with psoriasis differs from that in a normal population

Improving lean design of production systems by visualization support

The design process of production systems is complex with many different aspects to consider for efficiently developing and installing an effective system. Important success factors during the design process are typically the abilities to identify and manage risks, develop mitigation plans, and conduct timely proactive problem solving. The work reported in this paper is part of research addressing methods for how the design process can be supported by using virtual representations of the factory environments captured with 3D laser scanning. This support is evaluated in an industrial study of one industrialization project in the manufacturing industry. The industrialization project follows the process to design layout, work places, and plan for installation of new equipment to create a production system within a refurbished shop floor area. The area will include CNC machining centers, welding stations, product inspection, product cleaning, and material handling. 3D laser scanning is used to provide an accurate and realistic virtual representation of the current shop floor area. This virtual representation is combined with 3D CAD models of the new machining centers and other equipment to provide a realistic visualization of the planned production system. The research approach and its questions investigate the benefits of combining the lean principles to design and development of production systems using a realistic visualization, which include systematic risk analysis and problem solving as important activities. The result shows that visualization support gave a great advantage to identify the possible risks and problems, which resulted in higher confidence and substantial timesaving in planning and execution of the industrialization project

Characterisation of Functional Pressing Die Surfaces

The manufacture of dies and moulds is a critical aspect of many production systems since the manufacturing and try-out of new dies and moulds often is essential in determining the lead-time and quality of a new production system. In the automotive industry, many new car models are introduced each year and for each of these models, a new set of pressing dies has to be designed and manufactured. The manufacturing of pressing dies consists of several different process steps of which machining and manual polishing contribute largely to the time and cost. To be able to improve the manufacturing processes rationally, for example by optimising the machining to reduce or eliminate the subsequent manual work, an appropriate specification of the required surface quality, using a relevant parametric description of the surface, is needed. In pressing dies, the effects of manufacturing processes on functional performance are not fully understood. One of the reasons for this is the lack of effective methods for characterisation. In the work described in this thesis, research is conducted to evaluate and establish such methods.It was found that surface roughness measurement of dies, with the purpose of manufacturing process development, requires 3D data. Replication often needs to be used in these cases since dies usually are too large to bring into a lab measurement equipment. The replication techniques tested in this thesis work adequately. For quality control in production 2D measurements from a handheld instrument are good enough if an appropriate measuring strategy is used and limits for the evaluated parameters are defined.Using a multi-scale approach when analysing roughness data it may be possible to find so called functional bandwidths. With the analysis focused on the functional bandwidth the characterisation is more effective and it is easier to identify roughness parameters which correlate to the functional property or the process parameter of interest. Such a method for functional filtering of roughness data is developed and presented in the thesis.Surface texture anisotropy has been found to be important for the function of a die surface. It has also been observed that texture anisotropy can vary depending on the scale of observation. The method developed in this work to analyse and visualise texture anisotropy as a function of scale can be a helpful tool when evaluating die surfaces, especially when analysing surfaces produced with different manufacturing methods to make sure that the manufactured surface has the required texture properties in the relevant scales

Multiscale characterizations of surface anisotropies

Anisotropy can influence surface function and can be an indication of processing. These influences and indications include friction, wetting, and microwear. This article studies two methods for multiscale quantification and visualization of anisotropy. One uses multiscale curvature tensor analysis and shows anisotropy in horizontal coordinates i.e., topocentric. The other uses multiple bandpass filters (also known as sliding bandpass filters) applied prior to calculating anisotropy parameters, texture aspect ratios (Str) and texture directions (Std), showing anisotropy in horizontal directions only. Topographies were studied on two milled steel surfaces, one convex with an evident large scale, cylindrical form anisotropy, the other nominally flat with smaller scale anisotropies; a EDMed surface, an example of an isotropic surface; and an additively manufactured surface with pillar-like features. Curvature tensors contain the two principal curvatures, i.e., maximum and minimum curvatures, which are orthogonal, and their directions, at each location. Principal directions are plotted for each calculated location on each surface, at each scale considered. Histograms in horizontal coordinates show altitude and azimuth angles of principal curvatures, elucidating dominant texture directions at each scale. Str and Std do not show vertical components, i.e., altitudes, of anisotropy. Changes of anisotropy with scale categorically failed to be detected by traditional characterization methods used conventionally. These multiscale methods show clearly in several representations that anisotropy changes with scale on actual surface measurements with markedly different anisotropies

Temporary Employment and the Future Labor Market Status

The aim of this article is to describe and explain the development of temporary employment in Sweden between 1992 and 2010, and to investigate the effect of temporary employment for individuals’ future career on the labor market. The article analyzes temporary employees’ status transitions on the labor market using Swedish Labour Force Survey (LFS) data for the period 1992–2010. Each cohort consists of 2-year panels and focuses on changes between the first and last measuring points. The findings indicate that the specific type of temporary employment is crucial as regards whether or not it constitutes a stepping-stone toward permanent employment. The chances are greater in the case of, for example, substitutes, but are considerably less in the case of on-call employment. Certain types of temporary employment thus seem to be used by the employer to screen the employability of the employee, while others are used for achieving flexibilit

En jämförande kostnadsanalys av maskinsystem för upparbetning och transport av GROT

En kostnadsjämförelse av fyra maskinsystem för sönderdelning och transport av GROT vid avlägg har utförts för att identifiera kostnadspåverkande faktorer samt finna de mest lönsamma maskinsystemen inom hanteringskedjan för GROT. Studerade maskinsystem var TOMO hugglink med en flisbil; Skotarburen flishugg och skopbil; Huggbil med lastväxlare och containersystem; Willibald kross och dumper med containersystem. Respektive maskinsystem körs av entreprenörer från Norra Skogsägarna och fakturerade kostnader från 15 utförda trakter per maskinsystem och entreprenör har analyserats med avseende på transportavstånd och avläggstorlek. Fakturerade kostnader har sedan jämförts med kostnader beräknade utifrån ekonomiska modeller med annuitetsmetoden och vetenskapliga rapporter som grund. I modellerna har medtagits fasta maskinkostnader, maskinutnyttjande, personalkostnader, rörliga kostnader samt förväntad prestation där prestationen utgjorts av ett medeltal från minst två vetenskapliga rapporter. Resultaten har redovisats grafiskt. Huggbil med containersystem är det i praktiken billigaste systemet för sönderdelning och transport av GROT vid avlägg. Skillnaden mellan fakturerad och beräknad kostnad varierar i denna studie mellan 45-69 SEK/m3f för studerade maskinsystem. I modellen är Skotarburen flishugg och skopbil det billigaste systemet upp till 40 km transportavstånd då Huggbil med containersystem blir billigast. TOMO Hugglink med en flisbil är ett maskinsystem med stor potential då det med en flistrailer och 29 % teknisk utnyttjandegrad på huggen ändå konkurrerar med de andra maskinsystemen. Kostnadsvariationerna för Willibald kross och dumper med containersystem är stora och på medeltransportavståndet är det dyrast av de fyra systemen.A comparison of the costs of four machines for chipping and transport of logging residues at landings has been performed to identify costs and find the most profitable machine systems within the chipping and transport chain. Machine systems studied were TOMO hugglink med en flisbil; Skotarburen flishugg och skopbil; Huggbil med lastväxlare och containersystem; Willibald kross och dumper med containersystem. Invoiced costs of 15 landings per machine were obtained from Norra Skogsägarna and analyzed regarding transport distance and volume of logging residues at landing. Chipping and transport were executed by one contracted entrepreneur per machine system. Invoiced costs have been compared with costs based on economic models and scientific reports. The models included fixed machine costs, machine utilization, personnel costs, variable costs and expected productivity. Productivity consisted of an average based on at least two scientific reports. All results were presented in graphs for illustrative comparison. Huggbil med containersystem is according to invoiced costs the system with the lowest costs for chipping and transport of logging residues at landings. The difference between model and invoiced costs varied between 45-69 SEK/m3f for the machine systems, respectively. According to the model Skotarburen flishugg och skopbil is the cheapest system up to transport distances of 40 km where Huggbil med containersystem becomes cheaper. TOMO Hugglink med en flisbil is a machine system that competes well with the other systems although it has a technical rate of utilization at 29 % and with only one chip trailer included. There were large variations in costs for Willibald kross och dumper med containersystem and on the average transport distance it is the most expensive system

Effect of past century mining activities on sediment properties and toxicity to freshwater organisms in northern Sweden

The release of toxic metals from local mining activities often represents a severe environmental hazard for nearby lake ecosystems. Previous studies on the impact of mining have primarily focused on single lakes, with less emphasis on spatial and temporal recovery patterns of multiple lakes within the same catchment, but with different hydrological connection and distance to the pollutant source. This knowledge gap prevents us from assessing the real environmental risk of abandoned mines and understanding ecosystem recovery. This study explores the intensity and spatial patterns of sediment contamination and the potential for ecosystem recovery in three lakes in close vicinity of a lead (Pb) and zinc (Zn) mine in Sweden that has been inoperative for >20 years. Dated (210Pb and 137Cs) sediment cores from each lake were used to reconstruct temporal patterns in trace element deposition and relate those with past mining activities. Results show that all lakes were affected by mining, indicated by increasing Pb and Zn concentrations and decreasing organic matter content, at the onset of mining. However, the extent and timing of mining impact differed between lakes, which was partly ascribed to differences in the historical use of tailings and settling ponds. Assessment of toxicity levels in sediments, based on normalized Probable Effect Concentration Quotient (PEC-Q) to organic matter content, provided more consistent results with the historical mining than conventional methods, showing a decreasing impact in lakes once the operations ceased. Still, sediment Pb concentrations were > 10 times higher than pre-mining values, evidencing the urgent need for remediation actions in the study lakes. This study highlights the importance of considering spatial heterogeneity in metal deposition, sediment organic matter content, and hydrological connectivity with tailings when risk assessments are performed in mining-impacted lakes. The use of normalized PEC-Q in toxic assessments is also recommended

Sustainable human-robot co-production for the bicycle industry

Bicycle production has not changed much over the last 100 years, it is still performed mainly by manual labor in mass production. During the global pandemic, the demand for ecologically friendly and customized transport has increased. Hence, customers start to impose the same requirements on bikes as on cars: they want more customized products and short delivery time. This publication describes an approach to transform bicycle manufacturing towards human-robot co-production to enable smaller batch sizes and production on-shoring. We list the challenges of this transformation, our applied methods, and presents preliminary results of the cobot-driven prototypes

The Operator 4.0: Human Cyber-Physical Systems & Adaptive Automation towards Human-Automation Symbiosis Work Systems

A vision for the Operator 4.0 is presented in this paper in the context of human cyber-physical systems and adaptive automation towards human-automation symbiosis work systems for a socially sustainable manufacturing workforce. Discussions include base concepts and enabling technologies for the development of human-automation symbiosis work systems in Industry 4.0