| 1. |
- Dian, Eszter, et al.
(författare)
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Validation of Detailed Geant4 Model for Thermal Neutron Scattering using the Results of Multi-Grid Detector Prototype Test at CNCS at SNS
- 2017
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Ingår i: 2017 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (NSS/MIC). - : IEEE. - 9781538622827
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Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) aspires to be the worlds leading neutron source of the upcoming decades, and sets the scope on replacing He-3 tube detectors where it is reasonably achievable. The Multi-Grid detector, an Ar/CO2-filled proportional chamber based on solid (B4C)-B-10 converter, is the most potent replacement technology for chopper spectroscopy. This study reproduces in a detailed Geant4 geometry of a neutron scattering instrument the data from the Multi-Grid demonstrator detector, that has been tested for a 1 year period, installed side-by-side to the He-3 tubes at the CNCS instrument at SNS. For the further understanding of the background of the detector, Monte-Carlo simulations were performed, with the ESS Coding Framework, using a Geant4 version extended with NXSG4 and NCrystal. A detailed and realistic model of the prototype was built and was validated via comparison against measured data. With this model, different sources of neutron scattering were determined and studied separately, providing a better understanding of the scattered neutron background. Due to these capabilities the model will be used in the further optimization of the detector, especially for the background reduction via shielding, which will lead to instruments with better signal-to-background ratio by design.
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| 2. |
- Huang, Yiqian, et al.
(författare)
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A Novel Maximum Distance Separable Code Based RIS-OFDM : Design and Optimization
- 2022
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Ingår i: 2022 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM 2022). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 1521-1526
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a novel maximum distance separable (MDS) code based and reconfigurable intelligent surface (RIS) assisted wireless communication system with orthogonal frequency division multiplexing (OFDM). Specifically, input bits are firstly divided into groups and their MDS codes are utilized to decide the amplitudes and phases of subcarriers. The introduction of the MDS code helps to increase the minimum Hamming distance between symbols and improve on the capability of error detection. Besides, the RIS is adopted to create additional paths between the radio frequency (RF) and the receiver as well as alter the signal phases with derived optimal solution. Benefiting from the strength of the RIS, the proposed system can better overcome multipath fading compared with conventional systems. Simulation results are presented to demonstrate the efficacy of the proposed system in terms of reducing bit error rate (BER) through multipath channels.
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| 3. |
- Kristan, Matej, et al.
(författare)
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The Ninth Visual Object Tracking VOT2021 Challenge Results
- 2021
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Ingår i: 2021 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW 2021). - : IEEE COMPUTER SOC. - 9781665401913 ; , s. 2711-2738
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2021 is the ninth annual tracker benchmarking activity organized by the VOT initiative. Results of 71 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in recent years. The VOT2021 challenge was composed of four sub-challenges focusing on different tracking domains: (i) VOT-ST2021 challenge focused on short-term tracking in RGB, (ii) VOT-RT2021 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2021 focused on long-term tracking, namely coping with target disappearance and reappearance and (iv) VOT-RGBD2021 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2021 dataset was refreshed, while VOT-RGBD2021 introduces a training dataset and sequestered dataset for winner identification. The source code for most of the trackers, the datasets, the evaluation kit and the results along with the source code for most trackers are publicly available at the challenge website(1).
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| 4. |
- Niu, Hong, et al.
(författare)
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On the Efficient Design of RIS-Assisted MIMO Transmission
- 2022
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Ingår i: 2022 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM 2022). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 2346-2351
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Konferensbidrag (refereegranskat)abstract
- Recently, reconfigurable intelligent surface (RIS) has arisen as an excellent technology for assisting wireless communications. In order to handle the intractable non-convex problem for jointly optimizing beamforming and PSs in multiple-input multipleoutput (MIMO) transmission, we propose a novel alternating direction (AD) method by maximizing the achievable rate (AR) at the receiver. Specifically, the initial problem is divided into the following two processes: i) optimizing the beamforming vector with fixed PSs, ii) determining a specific PS based on a closedform solution when the other PSs and beamforming are fixed. Simulation results corroborate that the proposed AD method provides robust attainable performance with reduced computational complexity compared to its traditional counterparts.
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| 5. |
- Niu, Hong, et al.
(författare)
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When the CSI from Alice to Bob is Unavailable : What Can Eve Do to Eliminate the Artificial Noise?
- 2022
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Ingår i: 2022 IEEE 96TH VEHICULAR TECHNOLOGY CONFERENCE (VTC2022-FALL). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Artificial noise elimination (ANE) has arisen as a possible countermeasure for mitigating the influence of artificial noise (AN) at the eavesdropper (Eve). However, conventional ANE schemes require the attainable channel state information (CSI) between the transmitter (Alice) and legitimate receiver (Bob), which reduces the feasibility of this proposal. In this paper, we investigate the issue of ANE without the CSI of Alice-Bob link by minimizing the artificial-noise-to-signal ratio (ANSR). Moreover, the detailed minor component analysis (MCA) algorithm is presented, and the computational complexity is quantified. Simulation results demonstrate that MCA can effectively degrade the influence of AN without the knowledge of CSI.
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| 6. |
- Xiao, Hanshen, et al.
(författare)
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Algorithms for Comparison in Residue Number Systems
- 2016
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Ingår i: 2016 Asia-Pacific Signal and Information Processing Association Annual Summit and Conference, APSIPA 2016. - 9789881476821
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Konferensbidrag (refereegranskat)abstract
- Residue Number Systems (RNSs) has been widely used in digital signal processing (DSP) systems and cases of fast computing, parallelism and fault tolerant because of its carry-free property. However, the comparison operation in an RNS is quite difficult and the computation cost is high, which are a significant limitation to apply it for division, scaling and overflow detection. Reverse conversions are used to the comparison operation in an RNS over last decades, where comparisons are carried out in a binary (weighted) system rather than an RNS. Chinese Remainder Theorem (CRT) and Mixed-radix Conversion (MRC) are the two main methods to perform residue-to-binary (R2B) conversion. However, the calculation of mix-radix coefficients in MRC scheme is a strictly sequential manner, while modular and multiplication operations related to large numbers are required in CRT scheme although they can be implemented in fully parallel. Especially, in order to satisfy the requirements of wide word binary operations such as public-key cryptography and modern digital signal processing (DSP), neither CRT nor MRC is a suitable solution for comparison in an RNS when the processed numbers are large enough. In the paper, novel comparison algorithms are proposed, which achieve comparison operation in an RNS directly without R2B reverse conversions. Even the average time complexity of the algorithm carried out in a sequential manner is O (1). To the best of our knowledge, the proposed algorithms first achieve all calculations for comparison in an RNS completed within each modulus channel in general cases.
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| 7. |
- Xiao, Sen, et al.
(författare)
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Effect of contact friction between seatbelt and human body model on simulation of rib fracture in frontal impact
- 2016
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Ingår i: Proceedings - 2016 8th International Conference on Measuring Technology and Mechatronics Automation, ICMTMA 2016; Macau; China; 11 March 2016 through 12 March 2016. - 2157-1473. - 9781509023127 ; 9 June 2016, s. 255-257
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Konferensbidrag (refereegranskat)abstract
- Seatbelt contact friction coefficient may have some influence on chest injury prediction because it can affect the position of the seatbelt during the impact. The objective was to study the influence of the seatbelt contact friction coefficient on predicted rib fracture outcome in frontal impact. Four simulations of frontal impact sled tests in the same environment were conducted wherein the contact friction coefficient between the seatbelt and the chest model was varied. A noticeable effect was observed wherein increasing friction coefficient which tended to cause a slight decrease in the number of predicted fractures. Despite this, the magnitude of sensitivity was small, suggesting that in the absence of other information arbitrary values of friction coefficient within a reasonable intermediate range may be justified for this specific test condition.
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| 8. |
- Alviano, Mario, et al.
(författare)
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The fourth answer set programming competition : Preliminary report
- 2013
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Ingår i: Logic Programming and Nonmonotonic Reasoning. - Berlin, Heidelberg : Springer. - 9783642405631 ; , s. 42-53
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Konferensbidrag (refereegranskat)abstract
- Answer Set Programming is a well-established paradigm of declarative programming in close relationship with other declarative formalisms such as SAT Modulo Theories, Constraint Handling Rules, PDDL and many others. Since its first informal editions, ASP systems are compared in the nowadays customary ASP Competition. The fourth ASP Competition, held in 2012/2013, is the sequel to previous editions and it was jointly organized by University of Calabria (Italy) and the Vienna University of Technology (Austria). Participants competed on a selected collection of benchmark problems, taken from a variety of research areas and real world applications. The Competition featured two tracks: the Model& Solve Track, held on an open problem encoding, on an open language basis, and open to any kind of system based on a declarative specification paradigm; and the System Track, held on the basis of fixed, public problem encodings, written in a standard ASP language.
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| 9. |
- Andersson, Nils-Eric, et al.
(författare)
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The influence of hot rolling on the variation of through thickness structure of AA7010 thick plates
- 1997
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Ingår i: Thermo-Mechanical Processing in Theory, Modelling & Practice. - Stockholm : Svenska fören. för materialteknik. - 9163054213 ; , s. 284-289
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The variation of through thickness structure and yield strength of AA7010-T7451 thick plate has been investigated. Grain size at different depths were determined qualitatively by using optical microscopy. Texture measurements were carried out using x-ray technique at the same depths as grain size studies. Tensile property tests have been performed and the EBSP technique has been used to compare the degree of recovered and recrystallized grain structure at different depths. Tensile testing determined through thickness variations in yield. The expected W shape of longitudinal yield strength through thickness was not observed. The yield strength decreases towards the center of the plate. An increasing amount of big recrystallized grains (through the thickness from T/8 towards the center of the plate) appears to be the reason behind the decreasing through thickness yield strength.
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| 10. |
- Andersson, Nils-Eric, et al.
(författare)
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The influence of hot rolling on the variation of through thickness structure of AA7010 thick plates
- 1996
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Ingår i: Thermomechanical processing in theory, modelling and practice [TMP]2. - 9163054213 ; , s. 284-289
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The variation of through thickness structure and yield strength of AA7010-T7451 thick plate has been investigated. Grain sizes at different depths were determined qualitatively by using optical microscopy. Texture measurements were carried out using X-ray technique at the same depths as grain size studies and tensile property tests have been performed. EBSP techdque has been used to compare the degree of recovered and recrystallized grain structure at different depths. Tensile testing determined through thickness variations in yield strength. The well known W shape of longitudinal yield strength variation through the thickness was not observed. The influence of texture on the yield strength measured is discussed.
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