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| 2. |
- Chen, Jian, et al.
(författare)
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Experimental Validation of Device Sizing on CMOS LC-VCO Phase Noise
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This work investigates the impact of device sizingon phase noise in CMOS LC-tank oscillators, based on specificdesigns and careful measurements. It experimentally verified thepreviously published equations and clarified some conflictingdesign guidelines. The conclusions are grounded on the faircomparison of seven VCOs with the core device width varyingfrom 40 um to 280 um. These VCOs are originated from the samedie by using Focused Ion Beam (FIB), guaranteeing the sameorder of process variation. With the aid of a switched capacitorbank, they are able to operate at practically same oscillationfrequency under the same bias. These conditions assure the faircomparison. It validated that phase noise from tail devices isstrongly dependent to core device size (14 dB from measurements)while phase noise from core devices themselves shows smallerdependence (4 dB). Design guidelines, applying to different tailnoise cases, are concluded and generally advise the minimumcore device width especially when tail noise is dominant.
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| 3. |
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| 4. |
- Chen, Jian, et al.
(författare)
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Sizing of MOS device in LC-tank oscillators
- 2007
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Ingår i: 2007 Norchip. - 9781424415168 ; , s. 90-95
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Konferensbidrag (refereegranskat)abstract
- Since previous publications show conflicting results about sizing device, relationship between device size and 1/f(2) phase noise is studied and closed-form equations are derived in order to help designers to size devices in LC-tank oscillators for good phase noise performance. The analysis is divided into two steps. Firstly, periodic noise transfer functions of each VCO noise source to the output of switch FETs are derived, and the impact of sizing on these functions is discussed. Secondly, phase noise equations are derived with these functions. Experiments show that phase noise predicted by the equations agrees with that from simulations.
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| 5. |
- Dematties, Dario, et al.
(författare)
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Deep Learning of Nanopore Sensing Signals Using a Bi-Path Network
- 2021
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 15:9, s. 14419-14429
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Tidskriftsartikel (refereegranskat)abstract
- Temporal changes in electrical resistance of a nanopore sensor caused by translocating target analytes are recorded as a sequence of pulses on current traces. Prevalent algorithms for feature extraction in pulse-like signals lack objectivity because empirical amplitude thresholds are user-defined to single out the pulses from the noisy background. Here, we use deep learning for feature extraction based on a bipath network (B-Net). After training, the B-Net acquires the prototypical pulses and the ability of both pulse recognition and feature extraction without a priori assigned parameters. The B-Net is evaluated on simulated data sets and further applied to experimental data of DNA and protein translocation. The B-Net results are characterized by small relative errors and stable trends. The B-Net is further shown capable of processing data with a signal-to-noise ratio equal to 1, an impossibility for threshold-based algorithms. The B-Net presents a generic architecture applicable to pulse-like signals beyond nanopore currents.
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| 6. |
- Hu, Chang-Kang, et al.
(författare)
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Native Conditional iSWAP Operation with Superconducting Artificial Atoms
- 2023
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Ingår i: Physical Review Applied. - 2331-7019. ; 20:3
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Tidskriftsartikel (refereegranskat)abstract
- Controlling the flow of quantum information is a fundamental task for quantum computers, which is unfeasible to realize on classical devices. Coherent devices, which can process quantum states are thus required to route the quantum states that encode information. In this paper we demonstrate experimentally the smallest quantum transistor with a superconducting quantum processor, which is composed of a collector qubit, an emitter qubit, and a coupler (transistor gate). The interaction strength between the collector and emitter qubits is controlled by the frequency and state of the coupler, effectively implementing a quantum switch. Through the coupler-state-dependent Heisenberg (inherent) interaction between the qubits, a single-step (native) conditional iSWAP operation can be applied. To this end, we find that it is useful to take into consideration the higher-energy level for achieving a native and high-fidelity transistor operation. By reconstructing the quantum process tomography, we obtain an operation fidelity of 92.36% when the transistor gate is open (iSWAP implementation) and 95.23% in the case of closed gate (identity gate implementation). The architecture has strong potential in quantum information processing applications with superconducting qubits.
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| 7. |
- Hu, Chang-Kang, et al.
(författare)
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Optimal charging of a superconducting quantum battery
- 2022
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Ingår i: Quantum Science and Technology. - : IOP Publishing. - 2058-9565. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- Quantum batteries are miniature energy storage devices and play a very important role in quantum thermodynamics. In recent years, quantum batteries have been extensively studied, but limited in theoretical level. Here we report the experimental realization of a quantum battery based on superconducting qutrit. Our model explores dark and bright states to achieve stable and powerful charging processes, respectively. Our scheme makes use of the quantum adiabatic brachistochrone, which allows us to speed up the battery ergotropy injection. Due to the inherent interaction of the system with its surrounding, the battery exhibits a self-discharge, which is shown to be described by a supercapacitor-like self-discharging mechanism. Our results paves the way for proposals of new superconducting circuits able to store extractable work for further usage.
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| 8. |
- She, Huimin, et al.
(författare)
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A Network-based System Architecture for Remote Medical Applications
- 2007
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Ingår i: Proceedings of the Asia-Pacific Advanced Network Meeting.
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Konferensbidrag (refereegranskat)abstract
- Nowadays, the evolution of wireless communication and networktechnologies enables remote medical services to be availableeverywhere in the world. In this paper, a network-based systemarchitecture adopting wireless personal area network (WPAN)protocol IEEE 802.15.4/Zigbee standard and 3G communicationnetworks for remote medical applications is proposed. In theproposed system, the number and type of medical sensors arescalable depending on individual needs. This feature allows thesystem to be flexibly applied in several medical applications.Furthermore, a differentiated service using priority scheduling anddata compression is introduced. This scheme can not only reducetransmission delay for critical physiological signals and enhancebandwidth utilization at the same time, but also decrease powerconsumption of the hand-held personal server which uses batteryas the energy source.
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| 9. |
- She, Huimin, et al.
(författare)
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Analysis of Traffic Splitting Mechanisms for 2D Mesh Sensor Networks
- 2008
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Ingår i: International Journal of Software Engineering and Its Applications. - 1738-9984. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- For many applications of sensor networks, it is essential to ensure that messages aretransmitted to their destinations within delay bounds and the buffer size of each sensor nodeis as small as possible. In this paper, we firstly introduce the system model of a mesh sensornetwork. Based on this system model, the expressions for deriving the delay bound and bufferrequirement bound are presented using network calculus theory. In order to balance trafficload and improve resource utilization, three traffic splitting mechanisms are proposed. Andthe two bounds are derived in these traffic splitting mechanisms. To show how our methodapplies to real applications, we conduct a case study on a fresh food tracking application,which monitors the food freshness status in real-time during transportation. The numericalresults show that the delay bound and buffer requirement bound are reduced while applyingtraffic splitting mechanisms. Thus the performance of the whole sensor network is improvedwith less cost.
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| 10. |
- She, Huimin, et al.
(författare)
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Analytical Evaluation of Retransmission Schemes in Wireless Sensor Networks
- 2009
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Ingår i: 2009 IEEE VEHICULAR TECHNOLOGY CONFERENCE. - 9781424425167 ; , s. 38-42
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Konferensbidrag (refereegranskat)abstract
- Retransmission has been adopted as one of the most popular schemes for improving transmission reliability in wireless sensor networks. Many previous works have been done on reliable transmission issues in experimental ways, however, there still lack of analytical techniques to evaluate these solutions. Based on the traffic model, service model and energy model, we propose an analytical method to analyze the delay and energy metrics of two categories of retransmission schemes: hop-by-hop retransmission (HBH) and end-to-end retransmission (ETE). With the experiment results, the maximum packet transfer delay and energy efficiency of these two scheme are compared in several scenarios. Moreover, the analytical results of transfer delay are validated through simulations. Our experiments demonstrate that HBH has less energy consumption at the cost of lager transfer delay compared with ETE. With the same target success probability, ETE is superior on the delay metric for low bit-error-rate (BER) cases, while HBH is superior for high BER cases.
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