The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Po-zhao Huang - One of the best experts on this subject based on the ideXlab platform.
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Learning of Hybrid Fuzzy Controller for the Optical Data Storage Device
IEEE ASME Transactions on Mechatronics, 2008Co-Authors: Po-zhao HuangAbstract:A hybrid track-seeking fuzzy controller for an optical disk drive (ODD) is proposed in this paper. The proposed hybrid fuzzy controller (HFC) smoothes the voltage applied to the sled motor and improves the track-seeking efficiency. The HFC consists of two subsystems including an intelligent time switch and a driving force controller. Both subsystems are designed based on fuzzy logic inferences. The main functions of the proposed HFC are to drive the optical head unit (OHU) to the target track neighborhood as fast as possible and smoothly park the OHU in the least time in the target track neighborhood. An automatic learning approach based on genetic algorithms (GAs) is proposed for learning the fuzzy rules for both the intelligent time switch and driving force controller. Modulated orthogonal membership functions are utilized in both fuzzy controllers to improve the GA learning efficiency. The number of parameters needed to parameterize the fuzzy rule base is greatly reduced with the modulated orthogonal membership functions. Compared to the conventional track-seeking controller currently utilized in most ODDs that employ a speed profile as the reference signal for the track-seeking feedback control system, the proposed HFC outperforms the conventional track-seeking control schemes. Experiments are performed to justify the performance comparison.
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SMC - Automatic Learning of Hybrid Fuzzy Controller for the Optical Data Storage Device
2006 IEEE International Conference on Systems Man and Cybernetics, 2006Co-Authors: Po-zhao HuangAbstract:A hybrid track seeking fuzzy controller for the optical Data Storage Device is proposed in this paper. It will be shown that the proposed hybrid fuzzy controller smoothes the applied voltage to the sled motor and improves the track seeking efficiency. The proposed hybrid fuzzy controller consists of two subsystems including parking time controller and driving force controller. Both subsystems are designed based on fuzzy inference. The hybrid fuzzy controller will on one hand drive the pickup as fast as possible to the neighborhood of target track, and on the other hand smoothly park the pickup so that the fine seek controller can take over the control of pickup. An automatic learning approach based on GA is proposed learning both fuzzy rules of parking time controller and driving force controller. To improve GA's learning efficiency, modulated orthogonal membership functions are utilized in both fuzzy controllers. Various experiments are made to justify the performance comparison.
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Automatic Learning of Hybrid Fuzzy Controller for the Optical Data Storage Device
2006 IEEE International Conference on Systems Man and Cybernetics, 2006Co-Authors: Po-zhao HuangAbstract:A hybrid track seeking fuzzy controller for the optical Data Storage Device is proposed in this paper. It was shown that the proposed hybrid fuzzy controller smoothes the applied voltage to the sled motor and improves the track seeking efficiency. The proposed hybrid fuzzy controller consists of two subsystems including parking time controller and driving force controller. Both subsystems are designed based on fuzzy inference. The hybrid fuzzy controller will on one hand drive the pickup as fast as possible to the neighborhood of target track, and on the other hand smoothly park the pickup so that the fine seek controller can take over the control of pickup. An automatic learning approach based on GA is proposed learning both fuzzy rules of parking time controller and driving force controller. To improve GA's learning efficiency, modulated orthogonal membership functions are utilized in both fuzzy controllers. Various experiments are made to justify the performance comparison.
Hua Li - One of the best experts on this subject based on the ideXlab platform.
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Thiadizoloquinoxaline-Based N-Heteroacenes as Active Elements for High-Density Data-Storage Device
ACS Applied Materials & Interfaces, 2018Co-Authors: Yang Li, Hua Li, Jianmei Lu, Zilong Wang, Cheng Zhang, Peiyang Gu, Wangqiao Chen, Qichun ZhangAbstract:A novel thiadiazoloquinoxaline (TQ)-based donor–acceptor (D–A)-type N-heteroacene (Py-1-TQ) has been demonstrated for promising applications in organic multilevel resistive memory Devices. Compared with its counterparts (Py-0-TQ and Py-2-TQ), which show flash-type binary memory behaviors, Py-1-TQ exhibits excellent nonvolatile write-once-read-many-times-type ternary memory effects with high ON2/ON1/OFF current ratios (105.8:103.4:1), which can be attributed to the different electron-withdrawing abilities between the pyrazine unit and TQ species that can induce stepwise D–A charge-transfer processes. These results suggest that TQ-based N-heteroacenes can be potentially useful in ultrahigh-density Data-Storage Devices through the rational D–A tuning.
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Towards Highly-Efficient Phototriggered Data Storage by Utilizing a Diketopyrrolopyrrole-Based Photoelectronic Small Molecule
Chemistry-an Asian Journal, 2016Co-Authors: Yang Li, Hua Li, Qingfeng Xu, Najun Li, Jinghui He, Dongyun Chen, Jianmei LuAbstract:A cooperative photoelectrical strategy is proposed for effectively modulating the performance of a multilevel Data-Storage Device. By taking advantage of organic photoelectronic molecules as Storage media, the fabricated Device exhibited enhanced working parameters under the action of both optical and electrical inputs. In cooperation with UV light, the operating voltages of the memory Device were decreased, which was beneficial for low energy consumption. Moreover, the ON/OFF current ratio was more tunable and facilitated high-resolution multilevel Storage. Compared with previous methods that focused on tuning the Storage media, this study provides an easy approach for optimizing organic Devices through multiple physical channels. More importantly, this method holds promise for integrating multiple functionalities into high-density Data-Storage Devices.
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Effect of a π-spacer between a donor and an acceptor on small molecule-based Data-Storage Device performance
Chemical Communications, 2013Co-Authors: Gang Wang, Hua Li, Qingfeng Xu, Najun Li, Jianmei Lu, Shifeng Miao, Qijian Zhang, Lihua WangAbstract:We demonstrate that replacing the hydrazone linkage by a linear π-spacer bridging a carbazole donor and a naphthalimide acceptor induces a critical change in molecular organization and electron density distribution in the conjugation backbone that correlates with a remarkable variation of memory performance from DRAM to WORM types.
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Thermally Stable Ternary Data-Storage Device Based on Twisted Anthraquinone Molecular Design
Journal of Physical Chemistry C, 2012Co-Authors: Yuhui Zhang, Hua Li, Qingfeng Xu, Najun Li, Jianmei Lu, Hao Zhuang, Yong Yang, Xufeng Xu, Lihua WangAbstract:Three donor–acceptor and twisted anthraquinone azo molecules were synthesized, and the effects of conjugated backbones length, alkyl chains length, and the thermal annealing temperature on the memory characteristics were explored. The Device based on Azo-02, which has longer conjugated backbone and alkyl chains, exhibited stable nonvolatile ternary memory behavior as the thermal annealing temperature increased, with basically the same switching threshold voltages and current ratios being ∼1:103.43:105.50. For the “counterpart” molecules (Azo-01 and Azo-03) film, defects appeared or disordered, crystal packing formed as the thermal annealing temperature increased, and the corresponding Devices exhibited no obvious conductance switching behaviors. The mechanism related to electrical switching properties and WORM (write-once-read-many-times) behaviors were elucidated through molecular simulation. The results demonstrated that the long-term thermally stable high-density Data-Storage Devices can be fabricated ...
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a small molecule based ternary Data Storage Device
Journal of the American Chemical Society, 2010Co-Authors: Hua Li, Qingfeng Xu, Najun Li, Jianfeng Ge, Jianmei Lu, Hongwei GuAbstract:High-density Data Storage (HDDS) is urgently required to address ongoing rapid increases in amounts of information. Here we present a prototype sandwich Device that has ternary Data-Storage performance. Three characteristic currents can be read out using a certain constant voltage after removal of the applied voltage. Two electron pull groups and one electron push group are identified as the species responsible for electron flow. We believe that our observation will offer an interesting and useful theoretical approach for a huge increase in the memory density of potential future Devices.
Hongwei Gu - One of the best experts on this subject based on the ideXlab platform.
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a small molecule based ternary Data Storage Device
Journal of the American Chemical Society, 2010Co-Authors: Hua Li, Qingfeng Xu, Najun Li, Jianfeng Ge, Jianmei Lu, Hongwei GuAbstract:High-density Data Storage (HDDS) is urgently required to address ongoing rapid increases in amounts of information. Here we present a prototype sandwich Device that has ternary Data-Storage performance. Three characteristic currents can be read out using a certain constant voltage after removal of the applied voltage. Two electron pull groups and one electron push group are identified as the species responsible for electron flow. We believe that our observation will offer an interesting and useful theoretical approach for a huge increase in the memory density of potential future Devices.
Angeliki Pantazi - One of the best experts on this subject based on the ideXlab platform.
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Nanopositioning with multiple sensors: MISO control and inherent sensor fusion
IFAC Proceedings Volumes, 2020Co-Authors: Abu Sebastian, Angeliki PantaziAbstract:Abstract There is a strong motivation for using multiple sensors for feedback control in ultrahigh accuracy Data Storage Devices such as a probe-based Data Storage Device. One elegant way to design such controllers using multiple sensors is to design a direct multi-input-single-output (MISO) controller using either the H 2 or H ∞ control design paradigm. In this paper we discuss the control of a micro-scanner used in a probe-based Data Storage Device. Two sensors, a global position sensor and medium derived positional information, are employed simultaneously. MISO controllers are designed to obtain the desired frequency separation in closed loop performance. These controllers are investigated in detail to understand their underlying structure and the inherent sensor fusion that takes place during the control. Comparisons are made with conventional Kalman filtering and H ∞ filtering problems.
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Nanopositioning With Multiple Sensors: A Case Study in Data Storage
IEEE Transactions on Control Systems Technology, 2012Co-Authors: Abu Sebastian, Angeliki PantaziAbstract:The use of multiple sensors for nanopositioning is well motivated in high-density Data-Storage Devices, such as probe-based Data Storage Devices. In these Devices, ultra-high positioning accuracies are desired over their lifetime in the presence of external disturbances. In addition to meeting the stringent requirements for nanopositioning, the use of multiple sensors lends itself for performing sensor fusion and obtaining reliable estimates of position and velocity. These estimates can be used for the detection of shocks and vibrations and the calibration of sensors. The objective of this work is to provide a comprehensive overview of the problem of nanopositioning using multiple sensors in the context of probe-based Data Storage. We present the control of a micro-scanner used in a probe-based Data-Storage Device with two sensors, a global thermal position sensor and medium-derived positional information. In one approach, Kalman and H∞ filtering are employed to perform sensor fusion, and the resulting state estimates in turn serve to design feedback controllers. An alternate approach is to design a multiple-input single-output controller using either the H2 or H∞ control paradigm. These controllers are investigated in detail to reveal the underlying structure and the inherent sensor fusion that takes place. Comparisons are made between the two approaches.
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Nanopositioning for probe-based Data Storage [Applications of Control]
IEEE Control Systems Magazine, 2008Co-Authors: Abu Sebastian, Angeliki Pantazi, Haris Pozidis, Evangelos EleftheriouAbstract:Probe-based Data-Storage Devices are being considered as an ultra-high-density, small- form-factor alternative to conventional Data Storage. The probe-based Data-Storage concept is derived from scanning-probe microscopy, where nanometer-sharp tips are used to interrogate and manipulate matter down to the atomic scale. One implementation of this concept is based on a thermomechanical principle for storing and retrieving Data encoded as nanometer-scale indentations in thin polymer films. Ultra-high densities of more than 1 Tb/in2 have been achieved with this scheme. A small-scaleprototype system comprising all of the elements of a probe- based Data Storage Device has been developed. One of the key challenges is the positioning of the Storage medium relative to the read/write probes with nanometer-scale accuracy. A microscanner with X/Y motion capability is used to position the Storage medium. Position information along both scan directions is provided by a pair of thermal position sensors. In addition, medium-derived position information provides a measure of the cross-track deviations in the Y-scan direction. Control architectures for both scan directions are presented. The X control architecture relies on thermal position sensors alone, whereas the Y control architecture relies on both the thermal position sensors and the medium-derived PES. Nanometer-scale positioning accuracies are achieved over a bandwidth of a few hundred hertz. Read/write demonstrations with sufficiently low error rates demonstrate the efficacy of the nanopositioning schemes employed.
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A servomechanism for a micro-electro-mechanical-system-based scanning-probe Data Storage Device
Nanotechnology, 2004Co-Authors: Angeliki Pantazi, Mark A. Lantz, Giovanni Cherubini, Haralampos Pozidis, Evangelos S. EleftheriouAbstract:Micro-electro-mechanical-system (MEMS)-based scanning-probe Data Storage Devices are emerging as potential ultra-high-density, low-access-time, and low-power alternatives to conventional Data Storage. One implementation of probe-based Storage uses thermomechanical means to store and retrieve information in thin polymer films. One of the challenges in building such Devices is the extreme accuracy and the short latency required in the navigation of the probes over the polymer medium. This paper focuses on the design and characterization of a servomechanism to achieve such accurate positioning in a probe-based Storage prototype. In our Device, the polymer medium is positioned on a MEMS scanner with x/y-motion capabilities of about 100 µm. The Device also includes thermal position sensors that provide x/y-position information to the servo controller. Based on a discrete state-space model of the scanner dynamics, a controller is designed using the linear quadratic Gaussian approach with state estimation. The random seek performance of this approach is evaluated and compared with that of the conventional proportional, integrator, and derivative (PID) approach. The results demonstrate the superiority of the state-space approach, which achieves seek times of about 4 ms in a ± 50 µm range. Finally, the experimental results show that closed-loop track following using the thermal position-sensor signals is feasible and yields a position-error standard deviation of approximately 2 nm.
Jianmei Lu - One of the best experts on this subject based on the ideXlab platform.
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Thiadizoloquinoxaline-Based N-Heteroacenes as Active Elements for High-Density Data-Storage Device
ACS Applied Materials & Interfaces, 2018Co-Authors: Yang Li, Hua Li, Jianmei Lu, Zilong Wang, Cheng Zhang, Peiyang Gu, Wangqiao Chen, Qichun ZhangAbstract:A novel thiadiazoloquinoxaline (TQ)-based donor–acceptor (D–A)-type N-heteroacene (Py-1-TQ) has been demonstrated for promising applications in organic multilevel resistive memory Devices. Compared with its counterparts (Py-0-TQ and Py-2-TQ), which show flash-type binary memory behaviors, Py-1-TQ exhibits excellent nonvolatile write-once-read-many-times-type ternary memory effects with high ON2/ON1/OFF current ratios (105.8:103.4:1), which can be attributed to the different electron-withdrawing abilities between the pyrazine unit and TQ species that can induce stepwise D–A charge-transfer processes. These results suggest that TQ-based N-heteroacenes can be potentially useful in ultrahigh-density Data-Storage Devices through the rational D–A tuning.
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Towards Highly-Efficient Phototriggered Data Storage by Utilizing a Diketopyrrolopyrrole-Based Photoelectronic Small Molecule
Chemistry-an Asian Journal, 2016Co-Authors: Yang Li, Hua Li, Qingfeng Xu, Najun Li, Jinghui He, Dongyun Chen, Jianmei LuAbstract:A cooperative photoelectrical strategy is proposed for effectively modulating the performance of a multilevel Data-Storage Device. By taking advantage of organic photoelectronic molecules as Storage media, the fabricated Device exhibited enhanced working parameters under the action of both optical and electrical inputs. In cooperation with UV light, the operating voltages of the memory Device were decreased, which was beneficial for low energy consumption. Moreover, the ON/OFF current ratio was more tunable and facilitated high-resolution multilevel Storage. Compared with previous methods that focused on tuning the Storage media, this study provides an easy approach for optimizing organic Devices through multiple physical channels. More importantly, this method holds promise for integrating multiple functionalities into high-density Data-Storage Devices.
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Effect of a π-spacer between a donor and an acceptor on small molecule-based Data-Storage Device performance
Chemical Communications, 2013Co-Authors: Gang Wang, Hua Li, Qingfeng Xu, Najun Li, Jianmei Lu, Shifeng Miao, Qijian Zhang, Lihua WangAbstract:We demonstrate that replacing the hydrazone linkage by a linear π-spacer bridging a carbazole donor and a naphthalimide acceptor induces a critical change in molecular organization and electron density distribution in the conjugation backbone that correlates with a remarkable variation of memory performance from DRAM to WORM types.
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Thermally Stable Ternary Data-Storage Device Based on Twisted Anthraquinone Molecular Design
Journal of Physical Chemistry C, 2012Co-Authors: Yuhui Zhang, Hua Li, Qingfeng Xu, Najun Li, Jianmei Lu, Hao Zhuang, Yong Yang, Xufeng Xu, Lihua WangAbstract:Three donor–acceptor and twisted anthraquinone azo molecules were synthesized, and the effects of conjugated backbones length, alkyl chains length, and the thermal annealing temperature on the memory characteristics were explored. The Device based on Azo-02, which has longer conjugated backbone and alkyl chains, exhibited stable nonvolatile ternary memory behavior as the thermal annealing temperature increased, with basically the same switching threshold voltages and current ratios being ∼1:103.43:105.50. For the “counterpart” molecules (Azo-01 and Azo-03) film, defects appeared or disordered, crystal packing formed as the thermal annealing temperature increased, and the corresponding Devices exhibited no obvious conductance switching behaviors. The mechanism related to electrical switching properties and WORM (write-once-read-many-times) behaviors were elucidated through molecular simulation. The results demonstrated that the long-term thermally stable high-density Data-Storage Devices can be fabricated ...
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a small molecule based ternary Data Storage Device
Journal of the American Chemical Society, 2010Co-Authors: Hua Li, Qingfeng Xu, Najun Li, Jianfeng Ge, Jianmei Lu, Hongwei GuAbstract:High-density Data Storage (HDDS) is urgently required to address ongoing rapid increases in amounts of information. Here we present a prototype sandwich Device that has ternary Data-Storage performance. Three characteristic currents can be read out using a certain constant voltage after removal of the applied voltage. Two electron pull groups and one electron push group are identified as the species responsible for electron flow. We believe that our observation will offer an interesting and useful theoretical approach for a huge increase in the memory density of potential future Devices.
