| 29621. |
- Keyvani, Ali, 1978-, et al.
(författare)
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Schema for Motion Capture Data Management
- 2011
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Ingår i: Lecture Notes in Computer Science. 3rd International Conference on Digital Human Modeling, ICDHM 2011. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 9783642217982 ; , s. 99-108
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Konferensbidrag (refereegranskat)abstract
- A unified database platform capable of storing both motion captured data and information about these motions (metadata) is described. The platform stores large motion captured data in order to be used by different applications for searching, comparing, analyzing and updating existing motions. The platform is intended to be used to choose a realistic motion in simulation of production lines. It is capable of supporting and handling different motion formats, various skeleton types and distinctive body regions in a uniform data model. Extended annotating system is also introduced to mark the captured data not only in the time domain (temporal) but also on different body regions (spatial). To utilize the platform, sample tests are performed to prove the functionality. Several motion captured data is uploaded to the database while MATLAB is used to access the data, ergonomically analyze the motions based on OWAS standard, and add the results to the database by automatic tagging of the postures.
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| 29622. |
- Keyvani, Ali, 1978-, et al.
(författare)
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Using methods-time measurement to connect digital humans and motion databases
- 2013
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Ingår i: Lecture Notes in Computer Science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0302-9743 .- 1611-3349. - 9783642391811 ; 8026:Part 2, s. 343-352
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Tidskriftsartikel (refereegranskat)abstract
- To simulate human motions in DHM tools, using techniques which are based on real human data is one promising solution. We have presented a solution in this study to connect motion databases with DHM tools. We have showed that using a motion database with MTM-based annotations is a promising way in order to synthesize natural looking motions. A platform consists of a Motion Database, a Motion Generator, and a DHM tool was introduced and tested. The results showed successful application of the presented platform in the designed test case. © 2013 Springer-Verlag.
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| 29623. |
- Khademi, Maha, et al.
(författare)
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Large Non-Volatile Frequency Tuning of Spin Hall Nano-Oscillators using Circular Memristive Nano-Gates
- 2024
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 45:2, s. 268-271
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Tidskriftsartikel (refereegranskat)abstract
- Spin Hall nano oscillators (SHNOs) are promising candidates for neuromorphic computing due to their miniaturized dimensions, non-linearity, fast dynamics, and ability to synchronize in long chains and arrays. However, tuning the individual SHNOs in large chains/arrays, which is key to implementing synaptic control, has remained a challenge. Here, we demonstrate circular memristive nano-gates, both precisely aligned and shifted with respect to nano-constriction SHNOs of W/CoFeB/HfOx, with increased quality of the device tunability. Gating at the exact center of the nano-constriction region is found to cause irreversible degradation to the oxide layer, resulting in a permanent frequency shift of the auto-oscillating modes. As a remedy, gates shifted outside of the immediate nano-constriction region can tune the frequency dramatically (>200 MHz) without causing any permanent change to the constriction region. Circular memristive nano-gates can, therefore, be used in SHNO chains/arrays to manipulate the synchronization states precisely over large networks of oscillators.
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| 29624. |
- Khademi, Seyran, 1981, et al.
(författare)
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Peak-to-Average-Power-Ratio (PAPR) reduction in WiMAX and OFDM/A systems
- 2011
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Ingår i: EURASIP Journal on Advances in Signal Processing. - : Springer Science and Business Media LLC. - 1687-6180. ; , s. Article Number: 38-
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Tidskriftsartikel (refereegranskat)abstract
- A peak to average power ratio (PAPR) reduction method is proposed that exploits the precoding or beamforming mode in WiMAX. The method is applicable to any OFDM/A systems that implements beamforming using dedicated pilots which use the same beamforming antenna weights for both pilots and data. Beamforming performance depends on the relative phase shift between antennas, but is unaffected by a phase shift common to all antennas. PAPR, on the other hand, changes with a common phase shift and this paper exploits that property. An effective optimization technique based on sequential quadratic programming is proposed to compute the common phase shift. The proposed technique has several advantages compared with traditional PAPR reduction techniques in that it does not require any side-information and has no effect on power and bit-error-rate while providing better PAPR reduction performance than most other methods.
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| 29625. |
- Khadir, Samira, et al.
(författare)
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Full optical characterization of single nanoparticles using quantitative phase imaging
- 2020
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Ingår i: Optica. - 2334-2536. ; 7:3, s. 243-248
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Tidskriftsartikel (refereegranskat)abstract
- This paper introduces a procedure aimed to quantitatively measure the optical properties of nanoparticles, namely the complex polarizability and the extinction, scattering, and absorption cross sections, simultaneously. The method is based on the processing of intensity and wavefront images of a light beam illuminating the nanoparticle of interest. Intensity and wavefront measurements are carried out using quadriwave lateral shearing interferometry, a quantitative phase imaging technique with high spatial resolution and sensitivity. The method does not require any preknowledge on the particle and involves a single interferogram image acquisition. The full determination of the actual optical properties of nanoparticles is of particular interest in plasmonics and nanophotonics for the active search and characterization of new materials, e.g., aimed to replace noble metals in future applications of nanoplasmonics with less-lossy or refractory materials.
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| 29626. |
- Khadir, Samira, et al.
(författare)
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Metasurface Optical Characterization Using Quadriwave Lateral Shearing Interferometry
- 2021
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Ingår i: ACS Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 8:2, s. 603-613
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Tidskriftsartikel (refereegranskat)abstract
- An optical metasurface consists of a dense and usually nonuniform layer of scattering nanostructures behaving as a continuous and extremely thin optical component with predefined phase, transmission and reflection profiles. To date, various sorts of metasurfaces (metallic, dielectric, Huygens-like, Pancharatman-Berry, etc.) have been introduced to design ultrathin lenses, beam deflectors, holograms, or polarizing interfaces. Their actual efficiencies depend on the ability to predict their optical properties and to fabricate nonuniform assemblies of billions of nanoscale structures on macroscopic surfaces. To further help improve the design of metasurfaces, precise and versatile postcharacterization techniques need to be developed. Today, most of the techniques used to characterize metasurfaces rely on light intensity measurements. Here, we demonstrate how quadriwave lateral shearing interferometry (QLSI), a quantitative phase microscopy technique, can achieve full optical characterization of metasurfaces of any kind, as it can probe the local phase imparted by a metasurface with high sensitivity and a spatial resolution that reaches the diffraction limit. As a means to illustrate the versatility of this technique, we present measurements on two types of metasurfaces, namely, Pancharatnam-Berry and effective-refractive-index metasurfaces, and present results on uniform metasurfaces, metalenses, and deflectors.
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| 29627. |
- Khaghanifard, Jalal, et al.
(författare)
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Nonlinear modelling of unimorph and bimorph magneto-electro-elastic energy harvesters
- 2023
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Ingår i: Applied Mathematical Modelling. - : Elsevier BV. - 0307-904X. ; 119, s. 803-830
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Tidskriftsartikel (refereegranskat)abstract
- This paper nonlinearly models cantilever-based functionally graded magneto-electro-elastic energy harvesters (FGMEEEH) for the first time. The coupled magneto-electro-mechanical model is obtained on the basis of the Euler-Bernoulli beam theory. A hybrid procedure including Ritz's method is then utilized to generate reduced order models for both asymmetric unimorph and symmetric bimorph configurations. The resulting sets of initial value problems, whose convergence will be examined, are then analytically solved using the method of multiple time scales for both the free vibrations and primary resonance cases. The analytical time-histories of the system are compared by those obtained numerically and excellent agreements between them are observed. In addition, simplifying the frequency response function of the system in the primary resonance case, the present findings are validated by those available in the literature for linear unimorph systems. The influences of the harvester configurations, base acceleration amplitude, the value of the tip mass, the material gradation index as well as the resistances of the piezoelectric and magnetic circuits on the nonlinear response of the system are also studied in detail. It is observed that FGMEEEEHs enjoy much more efficiency in comparison to piezoelectric-based systems.
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| 29628. |
- Khaibullin, R.I., et al.
(författare)
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An influence of the viscosity of polymer substrate on ion beam synthesis of iron granular films
- 2003
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Ingår i: Nuclear Instruments and Methods in Physics Research B. ; 206, s. 1115-1119
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Tidskriftsartikel (refereegranskat)abstract
- Iron granular films were synthesized in silicone polymers by implantation of 40 keV Fe ions with a fluence of1.25x10**17 ion/cm2 into viscous polymer substrates with various viscosity of 20–1000 Pa s. After the implantation the iron-implanted silicone substrates have been cured in the solid rubber-like state on the expiration of 72 h. The influenceof the substrate viscosity on the magnetic properties of the synthesized iron films was studied by ferromagnetic resonance(FMR) spectroscopy. It was shown that magnetic anisotropy and magnetization of the iron granular films is strongly and non-monotonically depended on the viscosity of silicone polymer under irradiation. Particularly, themaximal value of magnetization, 610 G, is observed for iron granular film synthesized at substrate viscosity on order of 70 Pa s. This value is higher than the magnetization of films obtained in silicone substrate implanted with iron ions in fully cured state.
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| 29629. |
- Khakurel, Krishna P., et al.
(författare)
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Macromolecular nanocrystal structural analysis with electron and X-rays: A comparative review
- 2019
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Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1420-3049. ; 24:19
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Forskningsöversikt (refereegranskat)abstract
- Crystallography has long been the unrivaled method that can provide the atomistic structural models of macromolecules, using either X-rays or electrons as probes. The methodology has gone through several revolutionary periods, driven by the development of new sources, detectors, and other instrumentation. Novel sources of both X-ray and electrons are constantly emerging. The increase in brightness of these sources, complemented by the advanced detection techniques, has relaxed the traditionally strict need for large, high quality, crystals. Recent reports suggest high-quality diffraction datasets from crystals as small as a few hundreds of nanometers can be routinely obtained. This has resulted in the genesis of a new field of macromolecular nanocrystal crystallography. Here we will make a brief comparative review of this growing field focusing on the use of X-rays and electrons sources.
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| 29630. |
- Khalajzadeh, Hourieh, et al.
(författare)
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Fifth International Workshop on Human Factors in Modeling / Modeling of Human Factors (HuFaMo'21)
- 2021
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Ingår i: Companion Proceedings - 24th International Conference on Model-Driven Engineering Languages and Systems, MODELS-C 2021. ; , s. 337-340
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Konferensbidrag (refereegranskat)abstract
- Studying human factors and experiences in modeling helps to gain knowledge on the process and use of modeling in practice to optimize system outcomes and user well-being. Moreover, to better support the human aspects of stakeholders and end-users of the software, incorporating the human aspects into software engineering processes from the early modeling and design stages is essential. Considering human factors in software design involves not only 1) studying in detail the interactions between users (humans), but also 2) studying the human factors of the end-users of the system. The HuFaMo workshop was established in 2015 to promote this form of research by creating a venue to discuss and disseminate these topics. The HuFaMo Workshop originally aimed at studying human factors for software systems (implemented or not) allowing humans to model. Hosted within the MODELS conference, the first four editions of the workshop benefited from a high-quality audience, allowing significant progress on this issue. For this fifth edition, we have widened the scope of the workshop to consider the modeling of human factors during the design of the software as well. This helps to study all types of relationships that modeling and human factors can have and their impact on processes, products, and end-users as well as others that might be affected by the system.
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