| 1. |
- Chen, Ling, et al.
(författare)
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Reliable and efficient RAR-based distributed model training in computing power network
- 2024
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Ingår i: Journal of Optical Communications and Networking. - 1943-0620 .- 1943-0639. ; 16:5, s. 527-540
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Tidskriftsartikel (refereegranskat)abstract
- The computing power network (CPN) is a novel network technology that integrates computing power from the cloud, edge, and terminals using IP/optical cross-layer networks for distributed computing. CPNs can provide an effective solution for distributed model training (DMT). As a bandwidth optimization architecture based on data parallelism, ring all-reduce (RAR) is widely used in DMT. However, any node or link failure on the ring can interrupt or block the requests deployed on the ring. Meanwhile, due to the resource competition of batch RAR-based DMT requests, inappropriate scheduling strategies will also lead to low training efficiency or congestion. As far as we know, there is currently no research that considers the survivability of rings in scheduling strategies for RAR-based DMT. To fill this gap, we propose a scheduling scheme for RAR-based DMT requests in CPNs to optimize the allocation of computing and wavelength resources considering the time dimension while ensuring reliability. In practical scenarios, service providers may focus on different performance metrics. We formulate an integer linear programming (ILP) model and a RAR-based DMT deployment algorithm (RDDA) to solve this problem considering four optimization objectives under the premise of the minimum blocking rate: minimum computing resource consumption, minimum wavelength resource consumption, minimum training time, and maximum reliability. Simulation results demonstrate that our model satisfies the reliability requirements while achieving corresponding optimal performance for DMT requests under four optimization objectives.
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| 2. |
- Li, Bo, et al.
(författare)
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Joint IT and Spectrum Resource Load Balancing for VNF Selection in Inter-Datacenter Elastic Optical Networks
- 2017
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Ingår i: 2017 16TH INTERNATIONAL CONFERENCE ON OPTICAL COMMUNICATIONS & NETWORKS (ICOCN 2017). - : IEEE. - 9781538632734
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Konferensbidrag (refereegranskat)abstract
- The selection of virtualized network functions (VNFs) in service provisioning is a critical issue in inter-datacenter elastic optical networks. In this paper, considering load balancing of IT and spectrum resources, we propose two joint balancing factors, i.e., Global Balancing factor (GB factor) and Local Balancing factor (LB-factor) for VNFs selection. Then a Joint-Optimization Selection (JOS) algorithm is designed based on the joint balancing factors. Simulation results show that GB-factor based JOS can achieve better performance compared with LB-factor based JOS and benchmark algorithm.
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| 3. |
- Li, Yajie, et al.
(författare)
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Distributed Model Training based on Data Parallelism in Edge Computing-enabled Elastic Optical Networks
- 2021
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Ingår i: IEEE Communications Letters. - 1558-2558 .- 1089-7798. ; 25:4, s. 1241-1244
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Tidskriftsartikel (refereegranskat)abstract
- IEEE The emergence of edge computing provides an effective solution to execute distributed model training (DMT). The deployment of training data among edge nodes affects the training efficiency and network resource usage. This letter aims for the efficient provisioning of DMT services by optimizing the partition and distribution of training data in edge computing-enabled optical networks. An integer linear programming (ILP) model and a data parallelism deployment algorithm (DPDA) are proposed to solve this problem. The performance of the proposed approaches is evaluated through simulation. Simulation results show that the proposed algorithm can deploy more DMT services compared with benchmark.
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| 4. |
- Li, Yajie, et al.
(författare)
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End-to-end URLLC slicing based on packet duplication in 5G optical transport networks
- 2020
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Ingår i: Journal of Optical Communications and Networking. - 1943-0620 .- 1943-0639. ; 12:7, s. 192-199
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Tidskriftsartikel (refereegranskat)abstract
- With the stringent requirements of high reliability and low latency, ultra-reliable low latency communications (URLLCs) are one of three typical services in the fifth generation of mobile network (5G) paradigm. The packet duplication (PD) technique has been proposed as a promising solution to satisfy the extreme requirements of URLLC services. However, the benefit of PD comes at the cost of doubling resource usage. This paper investigates how to efficiently perform end-to-end URLLC slicing based on PD in 5G optical transport networks. Two heuristic algorithms are proposed, including PD-based slicing with wavelength isolation (PDS-WI) and PD-based slicing with link isolation (PDS-LI). The target of this paper is to maximize the number of accommodated URLLC slices by optimizing the allocation of heterogenous resources. The time complexity of these two algorithms is analyzed in detail. With dynamic slice requests, simulations are performed to evaluate and compare their performance in terms of slice blocking probability and resource usage. Meanwhile, two different network scenarios are considered in simulation. Simulation results indicate that PDS-WI outperforms PDS-LI by accommodating more URLLC slices. © 2009-2012 OSA.
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| 5. |
- Li, Yajie, et al.
(författare)
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Side Channel Attack-Aware Resource Allocation for URLLC and eMBB Slices in 5G RAN
- 2020
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Ingår i: IEEE Access. - 2169-3536 .- 2169-3536. ; 8, s. 2090-2099
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Tidskriftsartikel (refereegranskat)abstract
- Network slicing is a key enabling technology to realize the provisioning of customized services in 5G paradigm. Due to logical isolation instead of physical isolation, network slicing is facing a series of security issues. Side Channel Attack (SCA) is a typical attack for slices that share resources in the same hardware. Considering the risk of SCA among slices, this paper investigates how to effectively allocate heterogeneous resources for the slices under their different security requirements. Then, a SCA-aware Resource Allocation (SCA-RA) algorithm is proposed for Ultra-reliable and Low-latency Communications (URLLC) and Enhanced Mobile Broadband (eMBB) slices in 5G RAN. The objective is to maximize the number of slices accommodated in 5G RAN. With dynamic slice requests, simulation is conducted to evaluate the performance of the proposed algorithm in two different network scenarios. Simulation results indicate that compared with benchmark, SCA-RA algorithm can effectively reduce blocking probability of slice requests. In addition, the usage of IT and transport resources is also optimized.
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| 6. |
- Liu, Daosheng, et al.
(författare)
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Suppression Mechanism of TiO 2 for the Partial Discharge of Oil-paper Insulation in Intensive Electric Field
- 2019
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Ingår i: Proceedings - IEEE International Conference on Dielectric Liquids. - 2153-3733 .- 2153-3725. ; 2019-June
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Konferensbidrag (refereegranskat)abstract
- With the rapid development of modern HVDC transmission technology, higher insulation properties are put forward on the oil-paper insulation system of the transformer, which determine the transformer service life to a certain extent. Traditional transformer oil-paper insulation is becoming increasingly difficult to meet the demands of insulation system with large capacity and miniaturization at ultra-high voltage level. In order to improve the insulation strength of oil-paper system, the insulation cellulose paper modified by TiO2 nanoparticles of different diameters (5 nm, 10 nm, 20 nm, 30 nm) were prepared, in addition, each of modified cellulose paper has different mass fraction of TiO2 nanoparticles (1%, 3%, 5%, 7% wt.). The partial discharge (PD) detection platform was established, and the partial discharge inception voltage (PDIV) values of the oil-paper insulation system with and without nanoparticles were measured. To investigate the PD characteristics, the PD waveforms and PD frequency spectrums of modified cellulose paper and the unmodified were obtained. The suppression mechanism of TiO2 nanoparticles on PD was explored through scanning electron microscope (SEM) observation. All the experiment results indicate that adding nano-TiO2 is beneficial to enhance the insulation properties of oil-paper insulation, and the optimum diameter and mass fraction of TiO2 nanoparticles to suppress oil-paper PD were obtained.
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| 7. |
- Tian, Chen, et al.
(författare)
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An effective modulation of bulk perovskite by V2CTx nanosheets for efficient planar perovskite solar cells
- 2023
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 11:10, s. 5015-5026
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Tidskriftsartikel (refereegranskat)abstract
- Crystallization modulation and defect passivation are key for high performance perovskite solar cells (PSCs) through suppressing defects in the surface and/or near the grain boundaries (GBs) of solution-processed perovskite films. In this work, we report simultaneous modulation of crystallization and passivation of defects for perovskites through a new vanadium carbide (V2CTx) MXene that is employed in an anti-solvent. The final modified perovskite film showed an improved crystallization, better energy level alignment and higher hole injection with a hole-transporting layer, leading to an increased power conversion efficiency from 20.1% up to 23.47% for planar PSCs, with enhanced device stability retaining over 90% of the initial PCE after 1000 hours exposure under 40-60% relative humidity at 25 degrees C. We have further employed the synchrotron radiation in situ grazing-incidence wide-angle X-ray scattering (GIWAXS) equipment to monitor the kinetic process of crystallization during spin-coating; it is notable that a lower dimensional perovskite structure (n < 3) was observed in the modified perovskite film during the process of dropping the antisolvent CB with V2CTx, which helps explain the enhanced device stability.
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| 8. |
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| 9. |
- Bao, Dongxuan, et al.
(författare)
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A Wirelessly Powered UWB RFID Sensor Tag With Time-Domain Analog-to-Information Interface
- 2018
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Ingår i: IEEE Journal of Solid-State Circuits. - : IEEE. - 0018-9200 .- 1558-173X. ; 53:8, s. 2227-2239
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a wirelessly powered radio frequency identification sensor tag with an analog-to-information interface. A time-domain interface, incorporating an ultra-lowpower impulse radio ultra-wideband (IR-UWB) transmitter (TX), is employed. The analog signal from the sensor is compared with a triangular waveform, resulting in a pulse-position modulation signal to trigger UWB pulses. Thanks to the high time-resolution IR-UWB radio, time intervals of the impulses can be used to represent the original input value, which is measured remotely on the reader side by a time-of-arrival estimator. This approach not only eliminates the analog-to-digital converter (ADC) but also significantly reduces the number of bits to be transmitted for power saving. The proposed tag is fabricated in a 0.18-mu m CMOS process with an active area of 2.5 mm(2). The measurement results demonstrate that a 300-kS/s sampling rate with a 6.7-bit effective number of bits (ENOB) is obtained via a UWB receiver with a sensitivity of -93 dBm and an integration window of 10 ns. The ENOB is improved to 7.3 bits when the integration window is reduced to 2 ns. The tag can be powered up by a -18-dBm UHF input signal. The power consumption of the proposed tag is 41.5 mu W yielding a 1.3-pJ/conv.step figure of merit, offering 9x and 67x improvements compared with the state of the art based on an ADC and a backscattering TX, and the tag based on an ADC and a narrowband TX, respectively.
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| 10. |
- Brawek, Bianca, et al.
(författare)
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A new approach for ratiometric in vivo calcium imaging of microglia
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Microglia, resident immune cells of the brain, react to the presence of pathogens/danger signals with a large repertoire of functional responses including morphological changes, proliferation, chemotaxis, production/release of cytokines, and phagocytosis. In vitro studies suggest that many of these effector functions are Ca2+-dependent, but our knowledge about in vivo Ca2+ signalling in microglia is rudimentary. This is mostly due to technical reasons, as microglia largely resisted all attempts of in vivo labelling with Ca2+ indicators. Here, we introduce a novel approach, utilizing a microglia-specific microRNA-9-regulated viral vector, enabling the expression of a genetically-encoded ratiometric Ca2+ sensor Twitch-2B in microglia. The Twitch-2B-assisted in vivo imaging enables recording of spontaneous and evoked microglial Ca2+ signals and allows for the first time to monitor the steady state intracellular Ca2+ levels in microglia. Intact in vivo microglia show very homogenous and low steady state intracellular Ca2+ levels. However, the levels increase significantly after acute slice preparation and cell culturing along with an increase in the expression of activation markers CD68 and IL-1β. These data identify the steady state intracellular Ca2+ level as a versatile microglial activation marker, which is highly sensitive to the cell's environment.
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