| 1. |
- Blomdell, Anders, et al.
(författare)
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Extending an Industrial Robot Controller-Implementation and Applications of a Fast Open Sensor Interface
- 2005
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Ingår i: IEEE Robotics & Automation Magazine. - 1070-9932. ; 12:3, s. 85-94
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Tidskriftsartikel (refereegranskat)abstract
- Many promising robotics research results were obtained during the late 1970s and early 1980s. Some examples include Cartesian force control and advanced motion planning. Now, 20 years and many research projects later, many technologies still have not reached industrial usage. An important question to consider is how this situation can be improved for future deployment of necessary technologies. Today, modern robot control systems used in industry provide highly optimized motion control that works well in a variety of standard applications. To this end, computationally intensive, model-based robot motion control techniques have become standard during the last decade. While the principles employed have been known for many years, deployment in products required affordable computing power, efficientengineering tools, customer needs for productivity/performance, and improved end-user competence in the utilization of performance features. However, applications that are considered nonstandard today motivate a variety of research efforts and system development to package results in a usable form. Actually, robots are not useful for many manufacturing tasks today, in particular those found in small and medium enterprises (SMEs). Reasonsinclude complex configuration, nonintuitive (for the shop floor) programming, and difficulties instructing robots to deal with variations in their environment. The latter challenge includes both task definitions and definition of motion control utilizing external sensors. The key word here is flexibility, and flexible motion control is particularly difficult since the user or system integrator needs to influence the core real-time software functions that are critical for the performance and safe operation of the system. We must find techniques that permit real-time motion controllers to be extended for new, demanding application areas.
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| 2. |
- Ericsson, Rolf
(författare)
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A Comparative Study of Head Development in Mexican Axolotl and Australian Lungfish: Cell Migration, Cell Fate and Morphogenesis
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The development of the vertebrate head is a complex process involving interactions between a multitude of cell types and tissues. This thesis describes the development of the cranial neural crest and of the visceral arch muscles in the head of two species. One, the Mexican axolotl (Ambystoma mexicanum), is a basal tetrapod, whereas the other, the Australian lungfish (Neoceratodus forsteri), belongs to the Dipnoi, the extant sister group of the Tetrapoda. The migration of neural crest cells, which form most of the bones and connective tissues in the head, and the morphogenesis of the jaw, was determined in the Mexican axolotl. It was shown that both the upper and lower jaws form from ventral condensations of neural crest cells in the mandibular arch. The dorsal condensation, earlier considered to give rise to the upper jaw, was shown to form the trabecula cranii.The normal spatio-temporal development of visceral arch muscles was investigated in both the Mexican axolotl and the Australian lungfish. In axolotl, the muscles tended to start forming almost simultaneously in all visceral arches at their future origins and extend towards their future insertions at the onset of muscle fibre formation. In lungfish, fibres formed simultaneously throughout most of each muscle anlage in the first and second visceral arch, but were delayed in the branchial arches. The anlagen were first observed at their future insertion, from which they developed towards future origins. To test the ability of neural crest cells to pattern the visceral arch muscles, migrating crest cells were extirpated from axolotl embryos, which resulted in a wide range of muscle malformations. In most cases, the muscles appeared in the right position but were small and extended in abnormal directions. This shows that neural crest cells are responsible not for the position of the muscles but for their correct anatomical pattern. Fate mapping showed that connective tissue surrounding myofibers is, at least partly, neural crest derived.In conclusion, the work presented in this thesis shows that although early development may map out the patterns of later development, the differences between axolotl and lungfish head development are not seen until during morphogenesis. Further investigation of morphogenesis is needed to explain the great variation of head morphology seen in vertebrates today.
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| 3. |
- Johansson, Rolf, et al.
(författare)
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Sensor Integration in Task-level Programming and Industrial Robotic Task Execution Control
- 2004
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Ingår i: Industrial Robot. - : Emerald. - 0143-991X. ; 31:3, s. 284-296
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Tidskriftsartikel (refereegranskat)abstract
- Presents an approach to improved performance and flexibility in industrial robotics by means of sensor integration and feedback control in task-level programming and task execution. Also presents feasibility studies in support of the ideas. Discusses some solutions to the problem using six degrees of freedom force control together with the ABB S4CPlus system as an illustrative example. Consider various problems in the design of an open sensor interface for industrial robotics and discusses possible solutions. Finally, presents experimental results from industrial force controlled grinding.
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| 4. |
- Eriksson, Anders, et al.
(författare)
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RPC-LAP : The Rosetta Langmuir probe instrument
- 2007
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Ingår i: Space Science Reviews. - : Springer Science and Business Media LLC. - 0038-6308 .- 1572-9672. ; 128:04-jan, s. 729-744
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Forskningsöversikt (refereegranskat)abstract
- The Rosetta dual Langmuir probe instrument, LAP, utilizes the multiple powers of a pair of spherical Langmuir probes for measurements of basic plasma parameters with the aim of providing detailed knowledge of the outgassing, ionization, and subsequent plasma processes around the Rosetta target comet. The fundamental plasma properties to be studied are the plasma density, the electron temperature, and the plasma flow velocity. However, study of electric fields up to 8 kHz, plasma density fluctuations, spacecraft potential, integrated UV flux, and dust impacts is also possible. LAP is fully integrated in the Rosetta Plasma Consortium (RPC), the instruments of which together provide a comprehensive characterization of the cometary plasma.
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| 5. |
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| 6. |
- Olsson, Tomas, et al.
(författare)
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Force Control and Visual Servoing Using Planar Surface Identification
- 2002
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Ingår i: Proceedings. ICRA '02.. - 0780372727 ; 4, s. 4211-4216
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Konferensbidrag (refereegranskat)abstract
- When designing flexible multi-sensor based robot systems, one important problem is how to combine the measurements fromdisparate sensors such as cameras and force sensors. In this paper,we present a method for combining direct force control and visualservoing in the presence of unknown planar surfaces. The controlalgorithm involves a force feedback control loop and a vision basedreference trajectory as a feed-forward signal. The vision system isbased on a constrained image-based visual servoing algorithm designedfor surface following, wherethe location and orientation of the planar constraint surface is estimated online using position-, force- and visual data.We show how data from a simple and efficient camera calibration method can be used in combination withforce and position data to improve the estimation and referencetrajectories.The method is validated through experiments involving force controlleddrawing on an unknown surface. The robot will grasp a pen and use itto draw lines between a number of markers drawn ona white-board, while the contact force is kept constant. Despite its simplicity, the performance of the method is satisfactory.
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| 7. |
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| 8. |
- Svensson, Kristian, et al.
(författare)
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The paternal allele of the H19 gene is silenced in a stepwise manner duringearly mouse development: the acetylation status of histones mya be involved in the generation of variegated expression patter
- 1998
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Ingår i: Development. - 0950-1991 .- 1477-9129. ; 125:1, s. 61-69
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Tidskriftsartikel (refereegranskat)abstract
- Transcriptional silencing can reflect heritable, epigenetic inactivation of genes, either singly or in groups, during the life-time of an organism. This phenomenon is exemplified by parent-of-origin-specific inactivation events (genomic imprinting) for a subset of mammalian autosomal genes, such as H19. Very little is known, however, about the timing and mechanism(s) of silencing of the paternal H19 allele during mouse development. Using a novel in situ approach, we present evidence that the silencing of the paternal H19 allele is progressive in the trophectodermal lineage during early mouse development and generates variegated expression patterns. The silencing process apparently involves recruitment of histone deacetylases since the mosaic paternal-specific H19 expression reappears in trichostatin A-treated mouse conceptuses, undergoing in vitro organogenesis. Moreover, the paternal H19 alleles of PatDup.d7 placentas, in which a region encompassing the H19 locus of chromosome 7 is bipaternally derived, partially escape the silencing process and are expressed in a variegated manner. We suggest that allele-specific silencing of H19 share some common features with chromatin-mediated silencing in position-effect variegation.
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| 9. |
- Azevedo, Flavio, et al.
(författare)
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Social and moral psychology of COVID-19 across 69 countries
- 2023
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Ingår i: Scientific Data. - : NATURE PORTFOLIO. - 2052-4463. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The COVID-19 pandemic has affected all domains of human life, including the economic and social fabric of societies. One of the central strategies for managing public health throughout the pandemic has been through persuasive messaging and collective behaviour change. To help scholars better understand the social and moral psychology behind public health behaviour, we present a dataset comprising of 51,404 individuals from 69 countries. This dataset was collected for the International Collaboration on Social & Moral Psychology of COVID-19 project (ICSMP COVID-19). This social science survey invited participants around the world to complete a series of moral and psychological measures and public health attitudes about COVID-19 during an early phase of the COVID-19 pandemic (between April and June 2020). The survey included seven broad categories of questions: COVID-19 beliefs and compliance behaviours; identity and social attitudes; ideology; health and well-being; moral beliefs and motivation; personality traits; and demographic variables. We report both raw and cleaned data, along with all survey materials, data visualisations, and psychometric evaluations of key variables.
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| 10. |
- Backofen, Rolf, et al.
(författare)
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Requirements and specification of bioinformatics use cases
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This deliverable specifies use cases based on bioinformatics research carried out by members ofA2. The use cases involve the use of rules to reason over ontologies and pathways (Dresden,Edinburgh, Paris, Linköping) and rules to specify workflows to integrate bioinformatics data (Lisbon, Skövde, Jena, Bucharest). The use cases are designed as a reference point to foster the take up of A2 use cases by I-work packages. Most notably, many of the use cases specify the need for querying and reactivity with languages like Xcerpt (I4), Erus (I5) and Prova (I5). The use cases range from basic research applications to fully deployed software with an international user base.
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