| 1. |
- Johansson, Andreas, et al.
(författare)
-
Dynamic analysis of shuttle technique performance applied on hydraulic transformer
- 2002
-
Ingår i: Proc. of the 3rd International Fluid Power Conference (IFK'3). - 9783826599002 ; , s. 249-261
-
Konferensbidrag (refereegranskat)abstract
- As an alternative to traditional valve coutrol, hydraulic transformation has proved to be an attactive approach from an efficiency point of view. According to the Innas1 concept, hydraulic transformation is achicved using a modified displacement machine design. In order to realise the transformation using only one displacement machine, it is necessary to use a valve plate containing three kidney slots for the three supply lines: supply, load and tank. By displacing the valve plate, pressure/flow ratio can be transformed, ideally with preserved efficiency. When using three kidney slots together with a traditional displacement machine with two dead centres, the commutation between two subsequent kidneys will occur while the piston is moving. This will result in pre-compression or decompression of the cylinder fiuid, with severe pressure peaks as a consequence. Besides noise and vibration, these pressure peaks will decrease the total efficiency considerably. Also driving shaft torque variations will appear, which will affect the rotational movement by speed fluctuations. In order to minimise the pressure peaks during valving land passages. small pistons between pairs of cylinders in the barrel are introduced. This is referred to as shuttle technique. Using these shuttles, excess of cylinder fluid during commutation can be transferred to adjacent cylinders, and thus prevent cylinder pressure peaks from appearing.It is very difficult to measure the internal states of the shuttle in an operating transformer. By using computer simulation techniques, detailed analyses of the internal workings of the shuttle can be performed. In this work, a detailed description of the dynamic behaviour of the shuttle is given. Advantages and disadvantages of the technique are discussed.1 Innas BV, Netherlands
|
|
| 2. |
|
|
| 3. |
- Johansson, L. Ronnie M., et al.
(författare)
-
Bridging the gap between information need and information acquisition
- 2004
-
Ingår i: Proceedings of the Seventh International Conference on Information Fusion, FUSION 2004. - Stockholm. - 917056115X ; , s. 1202-1209
-
Konferensbidrag (refereegranskat)abstract
- In this article, we address the rarely discussed problem of connecting high-level information (e.g., aggregated states and enemy intentions) to information acquisition. Our approach is to partition the transition of information need to sensor management into a set of comprehensible entities (information types and functions), which we present in a framework. The framework is stepwise (sequential) and first translates actual information (from the data and information fusion process) to information need. The information need is mapped to the task space by a task management function which performs prioritization with respect to information need. A further step includes projection of tasks to service space by an allocation scheme, and finally services give orders to resources. In the terminology of the framework, we discuss the extension of a previous study (that involved plan recognition) with a sensor management function.
|
|
| 4. |
|
|
| 5. |
- Johansson, Ronnie
(författare)
-
Information Acquisition in Data Fusion Systems
- 2003
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- By purposefully utilising sensors, for instance by a datafusion system, the state of some system-relevant environmentmight be adequately assessed to support decision-making. Theever increasing access to sensors o.ers great opportunities,but alsoincurs grave challenges. As a result of managingmultiple sensors one can, e.g., expect to achieve a morecomprehensive, resolved, certain and more frequently updatedassessment of the environment than would be possible otherwise.Challenges include data association, treatment of con.ictinginformation and strategies for sensor coordination.We use the term information acquisition to denote the skillof a data fusion system to actively acquire information. Theaim of this thesis is to instructively situate that skill in ageneral context, explore and classify related research, andhighlight key issues and possible future work. It is our hopethat this thesis will facilitate communication, understandingand future e.orts for information acquisition.The previously mentioned trend towards utilisation of largesets of sensors makes us especially interested in large-scaleinformation acquisition, i.e., acquisition using many andpossibly spatially distributed and heterogeneous sensors.Information acquisition is a general concept that emerges inmany di.erent .elds of research. In this thesis, we surveyliterature from, e.g., agent theory, robotics and sensormanagement. We, furthermore, suggest a taxonomy of theliterature that highlights relevant aspects of informationacquisition.We describe a function, perception management (akin tosensor management), which realizes information acquisition inthe data fusion process and pertinent properties of itsexternal stimuli, sensing resources, and systemenvironment.An example of perception management is also presented. Thetask is that of managing a set of mobile sensors that jointlytrack some mobile targets. The game theoretic algorithmsuggested for distributing the targets among the sensors proveto be more robust to sensor failure than a measurement accuracyoptimal reference algorithm.Keywords:information acquisition, sensor management,resource management, information fusion, data fusion,perception management, game theory, target tracking
|
|
| 6. |
- Johansson, Ronnie, et al.
(författare)
-
Perception Management : An Emerging Concept for Information Fusion
- 2003
-
Ingår i: Information Fusion. - : Elsevier. - 1566-2535. ; 4:3, s. 231-234
-
Tidskriftsartikel (refereegranskat)abstract
- The state-of-art of sensor management has been advanced to the extent where high-level information plays an increasingly important role. Recognizing the essential need of intelligent agents to perceive the environment to take appropriate actions, the article proposes the concept of perception management. It refers to controlling the process of data acquisition from the external world to enhance percepts obtained. The content of perception management is outlined and its relationship with sensor management is also discussed.
|
|
| 7. |
- Suzic, Robert, et al.
(författare)
-
Realization of a bridge between high-level information need and sensor management using a common DBN
- 2004
-
Ingår i: PROCEEDINGS OF THE 2004 IEEE INTERNATIONAL CONFERENCE ON INFORMATION REUSE AND INTEGRATION (IRI-2004). - NEW YORK : IEEE. ; , s. 606-611
-
Konferensbidrag (refereegranskat)abstract
- In a decision support system for military decision makers a plan recognition process provides estimates Of enemy plans. To respond to a changing and uncertain environment the plan recognition process requires timely and relevant information. We address the rarely discussed, yet crucial, issue of connecting the information needs of plan recognition to management of sensors. We have previously presented a framework for this purpose and here we give details of an implementation and provide some results. In our implementation both plan recognition, sensor management and the functions that connect them utilize the a priori knowledge stored in a Dynamic Bayesian Network.
|
|
| 8. |
|
|
