| 1. |
|
|
| 2. |
- Hansson, Linnea J., et al.
(author)
-
Autoplant—Autonomous Site Preparation and Tree Planting for a Sustainable Bioeconomy
- 2024
-
In: Forests. - : MDPI. - 1999-4907. ; 15:2
-
Journal article (peer-reviewed)abstract
- Sustainable forestry requires efficient regeneration methods to ensure that new forests are established quickly. In Sweden, 99% of the planting is manual, but finding labor for this arduous work is difficult. An autonomous scarifying and planting machine with high precision, low environmental impact, and a good work environment would meet the needs of the forest industry. For two years, a collaborative group of researchers, manufacturers, and users (forest companies) has worked together on developing and testing a new concept for autonomous forest regeneration (Autoplant). The concept comprises several subsystems, i.e., regeneration and route planning, autonomous driving (path planning), new technology for forest regeneration with minimal environmental impact, automatic plant management, crane motion planning, detection of planting spots, and follow-up. The subsystems were tested separately and integrated together during a field test at a clearcut. The concept shows great potential, especially from an environmental perspective, with significantly reduced soil disturbances, from approximately 50% (the area proportion of the area disturbed by disc trenching) to less than 3%. The Autoplant project highlights the challenges and opportunities related to future development, e.g., the relation between machine cost and operating speed, sensor robustness in response to vibrations and weather, and precision in detecting the size and type of obstacles during autonomous driving and planting.
|
|
| 3. |
- Johnsson, Helena, et al.
(author)
-
En pedagogisk idé för ingenjörsutbildningarna vid Luleå tekniska universitet
- 2009
-
Conference paper (peer-reviewed)abstract
- Utmärkande för Luleå tekniska universitet (LTU) har länge varit närheten mellan studenterna och lärarna vilket har manifesterats genom klassrumsundervisning, lärartillgänglighet, mindre studiegrupper, koncentrerade campus etc. Undervisningsformerna har dock ändrats till att idag omfatta dels klassiska föreläsningar i stora studentgrupper, men också projektarbete i team där totalt sett 1/3 av all undervisning vid Luleå tekniska universitet sker i projektform. En fråga har ställts: Har Luleå tekniska universitet idag en gemensam pedagogisk idé för ingenjörsutbildningarna? I så fall är ytterligare en fråga hur denna pedagogiska idé tar sig uttryck i organisationen?Intervjuer med 40 aktiva lärare vid Luleå tekniska universitet har genomförts av projektgruppen (tillika författarna) varpå svaren har grupperats och analyserats i fjorton olika teman. Från dessa teman har sedan fyra hörnstenar i en definition av en pedagogisk idé aggregerats. Formuleringen av den pedagogiska idén lyder: Ett aktivt lärande för yrkeslivet – i branschnära projekt och med god vetenskaplig grund tränas förmågan att arbeta som ingenjör genom coachning från lärare i ett nära och öppet klimat. Idén har antagits av den tekniska fakultetsnämnden vid Luleå tekniska universitet och verifierats på institutionerna. Exempel på implementering och hur den pedagogiska idén aktivt verkar presenteras i artikeln.
|
|
| 4. |
- Karlberg, Andreas, et al.
(author)
-
Inventering av glosjöar i Västernorrlands län 2006
- 2008
-
Reports (other academic/artistic)abstract
- Länsstyrelsen i Västernorrlands län har under 2006 identifierat och besökt 26 vattendrag som har kontakt med havet och uppströmsliggande sjöar. Under inventeringen har bl.a. beskrivits vattendragens djup, vattenföring, temperatur, bottensubstrat,påverkan,vandringshinder m.m.Totalt finns 25 sjöar med biflöde sammanställda. Tre är kända sedan tidigare och har inte beskrivits utförligare i fält. 16 av de inventerade har bedömts som glosjöar enligt defintion ovan. Två har bedömts som glon och har alltså fortfarande brackvatteninflöde vid enstaka tillfällen.Det visade sig vara goda vandringsmöjligheter i flertalet av de inventerade bäckarna. Vägtrummor är den vanligaste orsaken till att fisk inte kan nå sina lekområden. Fem trummor utgör totalt hinder eller försvårar uppströmsvandring. Flera av dessa är också underdimensionerade, vilket skapar en onaturlig och hög vattenhastighet genom trummorna. 13 av glosjöarna har god förbindelse med havet, där de flesta arter, både stora och små individer kan vandra upp för lek. Ytterligare 9 glosjöar går att nå vid höga vattenstånd i havet eller av småväxta arter som t.ex. spigg.Det största hotet mot dessa små livsnerver i landskapet är vandringshinder, ofta vägpassager som underdimensioneras eller läggs fel. Många bäckar är också så små att under vissa delar av året kan de helt vara uttorkade och då tas sällan tillräcklig hänsyn. Det som utmärker glosjöar är att de ligger lågt i terrängen och det är utmärkande även för jordbruksmarker. Det är därför vanligt med jordbruksmark i direkt anknytning till glosjön eller anslutande bäck ner till havet. För den fiskvandring som sker om våren är kanske inte detta något större hot, utan den näringsrika grunda miljön, blir en trygg och god uppväxtmiljö för yngel. Men man påskyndar igenväxningen ganska drastiskt och det gör att dessa miljöer snabbare kommer att upphöra som lämpligt lekområde. Ökad näringstillförsel ger också snabbt väldigt tät vegetation som i vissa fall är så täta att i kombination med förmultnande växtdelar gör att fisk inte tar sig förbi.Det som utmärker glosjöar ytterligare är att eftersom de nyligen är avsnörda från havet så mynnar samtliga vattendrag i en vik i havet. Några objekt ligger uppströms en sjö och detta gäller inte dem förstås. Ur skydd- och bevarande perspektiv, så kan man säga att där vi har en glosjö har vi även en motsvarande värdefull livsmiljö ute i havet, då vikar med bäck är de produktionsmässigt viktigaste biotoperna
|
|
| 5. |
- Karlberg, Eva
(author)
-
Organizing the Voice of Women : A study of the Polish and Swedish women's movements' adaptation to international structures
- 2019
-
Doctoral thesis (other academic/artistic)abstract
- The European Union has become an important arena for international politics. Various actors try to influence the European-level executive and legislative authorities. Lobbyists in Brussels are not the only type of actors promoting the interests of others. Today, national-level social movement actors too are present at the European level, pushing the interests of various citizen groups and social issues. To do so, however, they need to adapt to the European Union’s multilevel governance system by speaking with one voice. As this thesis demonstrates, at the national level this adaptation may entail a number of organizational challenges for movements.Organizing the Voice of Women regards national-level social movements adapting to international structures. Taking the cases of the Swedish and the Polish women’s movements and their relation to the European Union as examples, the analysis follows two separate, yet similar, processes of forming and maintaining nationwide meta-organizations – that is, organizations of organizations – that can speak for the two respective movements. Through the cases of the two women’s movements’ adaptation to international structures, the study explores the challenges involved when a new layer of organization is added to a social movement.The results show that organizing the voice of the Swedish and the Polish women’s movements has been particularly challenging when conditions such as a tradition of umbrella organizing and stable financial resources are absent at national level. The results also show that competition and conflicts are apparent in both cases and inherent in meta-organizations, and that they have been possible to deal with differently depending on the two movements’ national settings. With an organizational perspective on social movement coalitions, this study contributes to the classic question of institutionalization, formalization and bureaucratization of social movements. It ultimately asks what it means to organize a field of social movement actors and what happens at the junction of organization and social movement, at the intersection of national and international interests. A wider implication of the study is that the issues it highlights are to be expected whenever the internationalization of national movement activities takes the form of meta-organization.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Latif, Saira, et al.
(author)
-
Outdoor tests of autonomous navigation system based on two different reference points of PurePursuit algorithm for 10-ton articulated vehicle.
- 2024
-
In: IEEE Access. - : IEEE. - 2169-3536. ; 12, s. 8413-8421
-
Journal article (peer-reviewed)abstract
- This work presents outdoor test results of autonomous navigation system based on two different reference points of PurePursuit algorithm for a 10-ton articulated research platform. PurePursit is commonly used simplified tracking algorithm based on geometric calculation of desired steering angle by pursuing certain number of points/distance ahead on given path from a fixed reference point of vehicle. Choice of fixed reference point effects the tracking accuracy particularly for articulated/center-steered vehicles. In this experimental work, PurePursuit algorithm with a virtual reference point(PPV) and commonly used front-axle reference point(PPF) is evaluated for heavy duty articulated vehicles in outdoor experiments. Experimental data shows that choice of reference point in PurePursuit algorithm for articulated vehicle has impact on tracking accuracy in terms of crosstrack errors and heading errors. Navigation tests were performed on a flat asphalt surface for paths of sharp complexities i-e a path with continuous curvature (circular path) and a path with sharp turns (zigzag path) with different initial conditions i-e initial position of vehicle. In general, it can be concluded that PurePursuit algorithm with front reference point (PPF) produced fewer crosstrack errors while PurePursuit algorithm with virtual midpoint reference (PPV) produced fewer heading errors.
|
|
| 9. |
|
|
| 10. |
- Li, Songyu, 1994-
(author)
-
Vision based perception systems for unmanned forestry machines
- 2023
-
Doctoral thesis (other academic/artistic)abstract
- After years of continuous development in the past decades, the field of forest production has achieved a notable degree of mechanization. Nonetheless, the unceasing demand for increased productivity in forestry operations continues to drive the rapid expansion of forestry automation. Critical aspects of forest production, including activities such as harvesting, forwarding, seedling planting, and soil preparation, hold significant potential for improved automation. These advancements promise numerous advantages, such as heightened production efficiency, reduced environmental impact, reduced operational costs, and the creation of a more favourable work environment. Beyond fostering industrial progress, such innovations could also make a positive contribution to the sustainable development of forestry.Forestry operations take place in intricate natural forest environments, rendering the automation of these processes complex and challenging. To realize full automation of forest machines, it is imperative to equip them with environmental awareness and cognitive capabilities. This can be achieved by integrating advanced imaging sensors with sophisticated algorithms, thereby enabling forest machinery to possess a vision system. By utilizing both novel and existing solutions for object detection, positioning, categorization, and status analysis within the machine's surroundings, combined with intelligent decision-making and control mechanisms, forest machinery can attain a higher degree of operational automation.This thesis primarily focuses on the development, deployment, and validation of vision systems on an unmanned forestry machine platform, with a special emphasis on the prototype development of essential features that are still manually executed in contemporary forestry operations. These features include forest terrain obstacle detection, roundwood pose estimation, automated selection of seedling planting locations, and autonomous obstacle avoidance for mounders.In this thesis, vision systems rooted in color and stereo camera sensing are designed and deployed on an unmanned forest machinery platform. These systems encompass the following key functionalities:• A precise positioning system for detecting forest terrain obstacles, such as stones and stumps, using stereo camera data in conjunction with deep learning techniques.• Localization and pose estimation capabilities for ground logs, leveraging stereo cameras and deep learning.• An analysis of the planning area for obstacle detection, along with the extraction of feasible planting zones for establishing seedling planting locations.• The development of an automated obstacle avoidance system for forestry mounders, powered by visual solutions.Through rigorous testing in real-world scenarios spanning logging, loading, planting, and site preparation, this paper demonstrates the feasibility and practicality of enhancing the level of automation in forest machinery operations through the integration of vision systems. It culminates in the creation of tangible and efficient functional prototypes, leading towards a new era of automation in the field of forestry.
|
|
