| 1. |
- Zotti, Laura, et al.
(författare)
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The Micro-Vertex-Detector for the bar PANDA experiment
- 2013
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 426
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Tidskriftsartikel (refereegranskat)abstract
- PANDA is a fixed target experiment that will be carried out at the future FAIR facility. PANDA will provide an excellent tool to address fundamental question in the field of hadronic physics, with a physic program that extends from the investigation of QCD (providing insight in the mechanisms of mass generation and confinement) to the test of fundamental symmetries. The Micro-Vertex-Detector located in the innermost part of the central tracking system will be composed by hybrid pixel and double-sided micro-strip silicon detectors. The Micro-Vertex-Detector will play an important role for the PANDA physics goals. The possibility to reconstruct the secondary vertices and the applicability of a precise D meson tagging is essential for the spectroscopy in the open charm sector and the charmonium mass region. To this aim the Micro-Vertex-Detector features a spatial resolution better than 100μm, a time resolution better than 20ns, a limited material budget, and a high data rate capability in a triggerless environment. An overview of the Micro-Vertex-Detector related to the physics goals will be presented.
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| 2. |
- Katselis, Dimitrios
(författare)
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Some Preamble Design Aspects in CP-OFDM Systems
- 2012
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Ingår i: IEEE Communications Letters. - 1089-7798 .- 1558-2558. ; 16:3, s. 356-359
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Tidskriftsartikel (refereegranskat)abstract
- A fundamental problem in training-based channel estimation for various communication systems is the preamble design. Two crucial aspects in such a design are the achievable mean square error (MSE) and the corresponding peak-to-average power ratio (PAPR). In this letter, preamble-based least squares (LS) channel estimation in CP-OFDM systems is considered. Ignoring the PAPR aspect, several MSE-optimal preambles and a necessary condition for their existence are presented. To this end, a training energy constraint, containing also the energy spent to the cyclic prefix (CP), is imposed. This constraint differs from the usual training energy constraints in the existing literature, which ignore the CP energy during training. These preambles contribute in the completion of existing results concerning MSE-optimal preambles in CP-OFDM systems. However, since high PAPR is an issue concerning these optimal designs, we show how these MSE-optimal preambles can be combined with the usual Zadoff-Chu (ZC) sequences to enlarge the class of PAPR-optimal preambles that achieve good MSE performance at the same time.
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| 3. |
- Aramrattana, Maytheewat, et al.
(författare)
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A Simulation Study on Effects of Platooning Gaps on Drivers of Conventional Vehicles in Highway Merging Situations
- 2021
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Ingår i: IEEE transactions on intelligent transportation systems (Print). - Piscataway, NJ : Institute of Electrical and Electronics Engineers Inc.. - 1524-9050 .- 1558-0016.
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Tidskriftsartikel (refereegranskat)abstract
- Platooning refers to a group of vehicles that--enabled by wireless vehicle-to-vehicle (V2V) communication and vehicle automation--drives with short inter-vehicular distances. Before its deployment on public roads, several challenging traffic situations need to be handled. Among the challenges are cut-in situations, where a conventional vehicle--a vehicle that has no automation or V2V communication--changes lane and ends up between vehicles in a platoon. This paper presents results from a simulation study of a scenario, where a conventional vehicle, approaching from an on-ramp, merges into a platoon of five cars on a highway. We created the scenario with four platooning gaps: 15, 22.5, 30, and 42.5 meters. During the study, the conventional vehicle was driven by 37 test persons, who experienced all the platooning gaps using a driving simulator. The participants' opinions towards safety, comfort, and ease of driving between the platoon in each gap setting were also collected through a questionnaire. The results suggest that a 15-meter gap prevents most participants from cutting in, while causing potentially dangerous maneuvers and collisions when cut-in occurs. A platooning gap of at least 30 meters yield positive opinions from the participants, and facilitating more smooth cut-in maneuvers while less collisions were observed.
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| 4. |
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| 5. |
- Fisher, AI, et al.
(författare)
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The first example of cobalt(III) mu-oxoacetate with water molecules in apical positions
- 2008
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Ingår i: Russian journal of general chemistry. - New York : Maik Nauka/Interperiodica. - 1070-3632 .- 1608-3350. ; 78:11, s. 2006-2012
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Tidskriftsartikel (refereegranskat)abstract
- Oxidation of Co(MeCOO)(2)center dot 4H(2)O with ozone in acetic acid followed by the treatment with nitric acid results in the formation of the trinuclear oxo-centered acetate complex [Co(III) (3)(mu(3)-O)(mu-O(2)CMe)(6)(OH(2))(3)] NO(3)center dot MeCOOH ([I]NO(3)center dot MeCOOH). Reasons of a decrease in the idealized symmetry of molecular structure (D (3h) -> D (3)) of the complex cation [I](+) were analyzed by means of quantum-chemical calculations. The complex does not retain its structure in solutions (in water, methanol, and ethanol).
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| 6. |
- Bagula, Antoine B
(författare)
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Traffic engineering next generation IP networks using gene expression programming
- 2006
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Ingår i: Proceedings of the 2006 IEEE. ; , s. 230-239
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Konferensbidrag (refereegranskat)abstract
- This paper addresses the problem of Traffic Engineering (TE) to evaluate the performance of evolutionary algorithms when used as IP routing optimizers and assess the relevance of using "Gene Expression Programming (GEP)" as a new fine-tuning algorithm In destination- and How-based TE. We consider a TE scheme where link weights are computed using GEP and used as either fine-tuning parameters in Open Shortest Path First (OSPF) routing or static routing cost In Constraint Based Routing (CBR). The resulting OSPF and CBR, algorithms are referred to as OSPFgep and CBRgep. The GEP algorithm is based on a hybrid optimisation model where local search complements the global search implemented by classical evolutionary algorithms to improve the genetic individuals fitness through hill-climbing. We apply the newly proposed TE scheme to compute the routing paths for the traffic offered to a 23-, 28- and 30-node test networks under different traffic conditions and differentiated services situations. We evaluate the performance achieved by the OSPFgep, CBRgep algorithms and OSPFma,destination-based routing algorithm where OSPF path selection Is driven by the link weights computed by a Memetic Algorithm (MA). We compare the performance achieved by the OSPFgep algorithm to the performance of the OSPFma and OSPF algorithms in a simulated routing environment using NS. We also compare the quality of the paths found by the CBRgep algorithm to the quality of the paths computed by the Constraint Shortest Path First (CSPF) algorithm when routing bandwidth-guaranteed tunnels using connection-level simulation. Preliminary results reveal the relative efficiency of (1) the OSPFgep algorithm compared to both the OSPFma and OSPF algorithms and (2) the CBRgep algorithm compared to CSPF routing.
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| 7. |
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| 8. |
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| 9. |
- Grizioti, Marianthi, et al.
(författare)
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Children as players, modders, and creators of simulation games : A design for making sense of complex real-world problems: Children as players, modders and creators of simulation games
- 2021
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Ingår i: Proceedings of Interaction Design and Children, IDC 2021. - New York, NY, USA : ACM Publications. - 9781450384520 ; , s. 363-374
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Konferensbidrag (refereegranskat)abstract
- Could computational thinking be a strong tool for children to understand complex 21st-century issues? Our knowledge is limited since most designs focus on sequential programming and on the cognitive aspects of computational thinking. This paper discusses a design that integrates ill-structured socio-scientific issues with programming and other computational concepts, in a playful and meaningful context. The design, called ChoiCo (Choices with Consequences), builds on the idea of "integrated affordances"that enables layered computational access, allowing children to be players and designers of choice-driven simulation games. We elaborate on a design-based research that studied children’s activity, who progressively played, modified and co-created games that simulated real-world issues. We describe four strategies developed by the children to make sense of the simulated problems through a systems thinking approach. We also discuss how they formulated these strategies by utilizing the affordances of map design, data manipulation and coding. © 2021 ACM.
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| 10. |
- Kiamehr, Ramin, 1968-
(författare)
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Precise Gravimetric Geoid Model for Iran Based on GRACE and SRTM Data and the Least-Squares Modification of Stokes’ Formula : with Some Geodynamic Interpretations
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Iran is one of the most complicated areas in the world from the view of rough topography, tectonic activity, large lateral density and geoidal height variations. The computation of a regional gravimetric geoid model with high accuracy in mountainous regions, especially with sparse data, is a difficult task that needs a special attention to obtain reliable results which can meet the needs of the today geodetic community.In this research different heterogeneous data has been used, which includes gravity anomalies, the high-resolution SRTM Digital Elevation Model (DEM), recently published GRACE Global Geopotential Models (GGMs), geological maps and GPS/levelling data. The above data has been optimally combined through the least-squares modification of Stokes formula with additive corrections. Regarding the data evaluation and refinement, the cross-validation technique has been used for detection of outliers. Also, several GGMs and DEMs are evaluated with GPS/levelling data. The impact of utilizing a high resolution SRTM DEM to improve the accuracy of the geoid model has been studied. Also, a density variation model has been established, and its effect on the accuracy of the geoid was investigated. Thereafter a new height datum for Iran was established based on the corrective surface idea. Finally, it was found that there is a significant correlation between the lateral geoid slope and the tectonic activities in Iran.We show that our hybrid gravimetric geoid model IRG04 agrees considerably better with GPS/levelling than any of the other recent local geoid models in the area. Its RMS fit with GPS/levelling is 27 cm and 3.8 ppm in the absolute and relative senses, respectively. Moreover, the relative accuracy of the IRG04 geoid model is at least 4 times better than any of the previously published global and regional geoid models in the area. Also, the RMS fit of the combined surface model (IRG04C) versus independent precise GPS/levelling is almost 4 times better compared to the original gravimetric geoid model (IRG04). These achievements clearly show the effect of the new gravity database and the SRTM data for the regional geoid determination in Iran based on the least-squares modification of Stokes’ formula.
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