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| 2. |
- Eklund, Anders J., et al.
(författare)
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Triple mode-jumping in a spin torque oscillator
- 2013
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Ingår i: 2013 22nd International Conference on Noise and Fluctuations, ICNF 2013. - New York : IEEE conference proceedings. - 9781479906680 ; , s. 6578965-
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Konferensbidrag (refereegranskat)abstract
- In a nano-contact Co/Cu/NiFe spin torque oscillator, mode-jumping between up to three frequencies within 22.5-24.0 GHz is electrically observed in the time domain. The measurements reveal toggling between two states with differing oscillation amplitude, of which the low-amplitude state is further divided into two rapidly alternating modes. Analysis of the mode dwell time statistics and the total time spent in each mode is carried out, and it is found that in both aspects the balance between the modes is greatly altered with the DC drive current.
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| 3. |
- Ellgardt, Anders, 1978-, et al.
(författare)
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Characteristics of a broad-band wide-scan fragmented aperture phased array antenna
- 2006
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Konferensbidrag (refereegranskat)abstract
- In this paper a phased array antenna is described that is designed with the help of a genetic algorithm for scan angles out to 60° from broadside. The focus is on simplifying the manufacturing of the diagonally adjoining pixels and on numerical results for thin antennas. The effects of the corner to corner contacts are studied and results for two synthesized elements ar Test and measurement requirements on wireless devices
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| 4. |
- Furuskär, Anders, et al.
(författare)
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Performance of WCDMA High Speed Packet Data
- 2002
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Ingår i: IEEE 55TH VEHICULAR TECHNOLOGY CONFERENCE, VTC SPRING 2002, VOLS 1-4, PROCEEDINGS. - New York : IEEE. - 0780374843 ; , s. 1116-1120
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Konferensbidrag (refereegranskat)abstract
- WCDMA release 5 supports peak bitrates for data services in the order of 10 Mbit/s, together with reduced delays and increased system throughput. In this paper, a brief introduction to release 5 is given and radio resource management principles associated with the high speed packet data bearers are discussed. Scheduling performance for WWW services, provision of bearers for streaming services, as well as the simultaneous use of high speed packet data bearers and conversational bearers is elaborated upon. Simulation results indicate that with appropriate radio resource management, all the above challenges may be successfully dealt with.
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| 5. |
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| 6. |
- Persson, Håkan, et al.
(författare)
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Investigation of Boundary Layer Behavior in Hcci Combustion Using Chemiluminescence Imaging
- 2005
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Ingår i: SAE, Session: Homogeneous Charge Compression Ignition (HCCI) (Part 6 of 6). - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. ; 114:4, s. 1358-1369
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Konferensbidrag (refereegranskat)abstract
- A five-cylinder diesel engine, converted to a single cylinder operated optical engine is run in Homogeneous Charge Compression Ignition (HCCI) mode. A blend of iso-octane and n-heptane is used as fuel. An experimental study of the horizontal boundary layer between the main combustion and the non-reacting surface of the combustion chamber is conducted as a function of speed, load, swirl and injection strategy. The combustion behaviour is monitored by chemiluminescence measurements. For all cases an interval from -10 to 16 crank angles after top dead center (CAD ATDC) in steps of one CAD are studied. One image-intensified camera observes the boundary layer up close from the side through a quartz cylinder liner while a second camera has a more global view from below to see more large scale structure of the combustion. The averaged chemiluminescence intensity from the HCCI combustion is seen to scale well with the rate of heat release. A boundary layer is defined and studied in detail between the main combustion volume and the piston crown surface as a function of crank angle. The boundary layer is found to be in the range from 2 to 4 mm for all cases by the definition used; however, the location for the measurements becomes more and more important as combustion becomes more inhomogeneous. To get accurate calculations, the level of noise must also be considered and definitions of boundary layer thickness should not be made at to low chemiluminescence intensity.
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| 7. |
- Persson, Håkan, et al.
(författare)
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Investigation of the Early Flame Development in Spark Assisted HCCI Combustion Using High Speed Chemiluminescence Imaging
- 2007
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Ingår i: SAE, Session: Homogeneous Charge Compression Ignition (HCCI) (Part 5 of 8) Optical Diagnostics. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International.
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Konferensbidrag (refereegranskat)abstract
- Auto-ignition with SI-compression ratio can be achieved by replacing some of the fresh charge by hot residuals. In this work an engine is run with a negative valve overlap (NVO) trapping hot residuals. By increasing the NVO, thus raising the initial charge temperature it is possible to investigate the intermediate zone between SI and HCCI as the amount of residuals is increased. Recent research has shown the potential of using spark assistance to aid gasoline HCCI combustion at some operating conditions, and even extend the operating regime into regions where unsupported HCCI combustion is impossible. In this work the influence of the spark is studied in a single cylinder operated engine with optical access. Combustion is monitored by in-cylinder pressure and simultaneous high speed chemiluminescence imaging. It is seen that even for large NVO and thus high residual fractions it is a growing SI flame that interacts with, and governs the subsequent HCCI combustion. Using the spark timing it is possible to phase the combustion timing even when the major part of the released heat is from HCCI combustion. The flame expansion speed is decreases for higher NVO, but prevails also for high residual fractions. A higher spark advance is found to compensate for the slower flame expansion up to a point. The auto-ignition process is found to be stratified for both spark assisted HCCI as well as for pure HCCI. For pure HCCI the initial front spreading velocity is found to be in the same order of magnitude as for the expansion speed of the SI flame. Calculations to estimate the crank angle of auto-ignition are performed based on cylinder pressure information providing good statistics on how the proportion of SI to HCCI behaves for different operating conditions.
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| 8. |
- Sahlgren, Magnus, et al.
(författare)
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The Gavagai Living Lexicon
- 2016
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Ingår i: 10th edition of the Language Resources and Evaluation Conference, 23-28 May 2016, Portorož (Slovenia). - : ELRA.
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Konferensbidrag (refereegranskat)abstract
- This paper presents the Gavagai Living Lexicon, which is an online distributional semantic model currently available in 14 different languages. We describe the underlying distributional semantic model, and how we have solved some of the challenges in applying such a model to large amounts of streaming data. We also describe the architecture of our implementation, and discuss how we deal with continuous quality assurance of the lexicon.
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| 9. |
- Tan, G., et al.
(författare)
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HLA federate migration
- 2005
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Ingår i: 38th Annual Simulation Symposium, Proceedings. - : IEEE Computer Society. - 0769523226 ; , s. 243-250
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Konferensbidrag (refereegranskat)abstract
- The High Level Architecture (HLA) is a standardized framework for distributed simulation that promotes reuse and interoperability of simulation components (federates). Federates are processes which communicate with each other in the simulation via the Run Time Infrastructure (RTI). When running a large scale simulation over many nodes/workstations, some may get more workload than others. To run the simulation as efficiently as possible, the workload should be uniformly distributed over the nodes. Current RTI implementations are very static, and do not allow any load balancing. Load balancing of a HLA federation can be achieved by scheduling new federates on the node with least load and migrating executing federates from a highly loaded node to a lightly loaded node. Process migration has been a topic of research for many years, but not within the context of HLA. This paper focuses on process migration within the HLA framework.
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