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排序方式: 共有123条查询结果,搜索用时 31 毫秒
21.
In this work, the normalized Internal Model Control (IMC) filter time constant is designed to achieve a specified value of the maximum sensitivity for stable first and second order plus time delay process models, respectively. Since a particular value of the maximum sensitivity results in an almost constant percentage overshoot to controller setpoint change, an empirical relationship between the normalized IMC filter time constant and percentage overshoot is presented. The main advantage of the proposed method is that only a user-defined overshoot is required to design a PI/PID controller. Simulation examples are given to demonstrate the value of the proposed method. 相似文献
22.
Electrical reliability aspects of HfO2 high-k gate dielectrics with TaN metal gate electrodes under constant voltage stress 总被引:1,自引:1,他引:0
The dielectric breakdown property of ultrathin 2.5 and 5.0 nm hafnium oxide (HfO2) gate dielectric layers with metal nitride (TaN) gate electrodes for metal oxide semiconductor (MOS) structure has been investigated. Reliability studies were performed with constant voltage stressing to verify the processing condition effects (film thicknesses and post metal annealing temperatures) on times to breakdown. The leakage current characteristics are improved with post metal annealing temperatures (PMA) for both 2.5 and 5.0 nm HfO2 physical thicknesses. However, it is more prominent (2 orders of magnitudes) for 2.5 nm HfO2 film thickness. The values of oxide-trapped charge density and interface-state density are also improved for 2.5 nm HfO2 film. The different stages of charge-trapping behaviors, i.e., stress-induced leakage current, soft and hard breakdown mechanisms have been detected. During constant voltage stress of the MOS capacitors, an increase in the time-dependent gate current is observed, followed by the occurrence of several fluctuations. The amplitude of the fluctuations is much larger in the 5.0 nm HfO2 gate dielectric layer compared to the 2.5 nm HfO2 layer. After the occurrence of such fluctuations, the current–voltage characteristics exhibited an increased in gate current compared to the fresh (unstressed) devices. 相似文献
23.
Narendra Bandaru Darshan Ajmera Krishna Manwani Sasmita Majhi Emila Panda 《Transactions of the Indian Institute of Metals》2017,70(5):1269-1275
High-resolution transmission electron microscopy analyses are carried out to understand the microstructure of the ultra-thin oxide-film grown on a (native) amorphous Al2O3-coated Al-0.8 at.% Mg alloy substrate at T = 600 K for t = 2 h and at pO2 of 1 × 10?2 Pa. This oxide-film is found to be non-uniformly thick with thicknesses varying from 1.50 to 4.60 nm. Occasionally, this oxide is found to diffuse into the Al–Mg alloy substrate, forming oxide thicknesses up to 10.5 nm. Overall, this oxide-film is found to consist of a mixed amorphous, (poly) crystalline and an intermediate amorphous-to-crystalline transition regions, with crystalline regions consisting mostly of MgO and the diffused oxide regions into the Al–Mg alloy substrate coated with γ-Al2O3. These observations are then compared with the experimental results obtained using angle-resolved X-ray Photoelectron Spectroscopy analysis and thermodynamic predictions for the growth of an ultra-thin oxide-film due to dry, thermal oxidation of Al–Mg alloy substrates. 相似文献
24.
This paper presents an improved automatic tuning method for stable processes using a modified relay in the presence of static load disturbances and measurement noise. The modified relay consists of a standard relay in series with a PI controller of unity proportional gain. The integral time constant of the PI controller of the modified relay is chosen so as to ensure a minimum loop phase margin of 30. A limit cycle is then obtained using the modified relay. Hereafter, the PID controller is designed using the limit cycle output data. The derivative time constant is obtained by maintaining the above mentioned loop phase margin. Minimizing the distance of Nyquist curve of the loop transfer function from the imaginary axis of the complex plane gives the proportional gain. The integral time constant of the PID controller is set equal to the integral time constant of the PI controller of the modified relay. The effectiveness of the proposed technique is verified by simulation results. 相似文献
25.
The paper studies the capacities of time hopping ultra wideband (TH-UWB) systems by adopting orthogonal pulse-based modulation
schemes in a multipath environment with the consideration of multiple access interference (MAI) and inter symbol interference
(ISI). Recently, orthogonal pulse-based modulation schemes such as pulse shape modulation (PSM), biorthogonal PSM (BPSM) and
the combination of orthogonal pulse position modulation (OPPM) and BPSM have been proposed for UWB system to reduce ISI and
MAI. In this paper, we first investigate the influences of ISI and MAI on the capacities of TH-UWB systems in terms of signal-to-interference
and noise ratio (SINR) for high-order modulation schemes based on various sets of orthogonal pulses. How mutual information
varies with the number of multipath components (MPCs) is then analyzed. The complete mathematical analysis and simulation
results are provided in detail. When maximizing the mutual information, the Gaussian distribution approximate is assumed to
describe the characteristics of MAI and ISI. Simulation results are provided to verify the theoretical analysis. Some conclusions
are drawn thereafter, such as that capacity depends on the pulse patterns adopted and mutual information varies with inversely
proportional to the number of MPCs. We also observed that the capacities of UWB systems for OPPM-BPSM schemes are larger than
those of PSM and BPSM schemes. 相似文献
26.
In recent years because of substantial use of wireless sensor network the distributed estimation has attracted the attention of many researchers. Two popular learning algorithms: incremental least mean square (ILMS) and diffusion least mean square (DLMS) have been reported for distributed estimation using the data collected from sensor nodes. But these algorithms, being derivative based, have a tendency of providing local minima solution particularly for minimization of multimodal cost function. Hence for problems like distributed parameters estimation of IIR systems, alternative distributed algorithms are required to be developed. Keeping this in view the present paper proposes two population based incremental particle swarm optimization (IPSO) algorithms for estimation of parameters of noisy IIR systems. But the proposed IPSO algorithms provide poor performance when the measured data is contaminated with outliers in the training samples. To alleviate this problem the paper has proposed a robust distributed algorithm (RDIPSO) for IIR system identification task. The simulation results of benchmark IIR systems demonstrate that the proposed algorithms provide excellent identification performance in all cases even when the training samples are contaminated with outliers. 相似文献
27.
JS Murthy KA Abraham S Rajagopal K Sudarsana HS Somanath 《Canadian Metallurgical Quarterly》1995,43(1):25-27
Clinical and haemodynamic profile of 107 adult patients above the age of 15 years with TOF was analysed. Cardiac catherization and selective cine-angiography were performed in all cases. Infundibular pulmonary stenosis, mal-alignment type of ventricular septal defect, mitral-aortic fibrous continuity and equal systolic pressures in both the ventricles and aorta were considered mandatory for the diagnosis of Tetralogy of Fallot. Aortic regurgitation was seen in 26 cases (24%), tricuspid regurgitation in 22 cases (21%), absent pulmonary valve in 3 cases (3%), branch pulmonary artery stenosis in 9 case (8.4%), major aortopulmonary collaterals in 15 cases (14%), right atrial pressure was more than 10 mmHg in 10 cases (11%) and right ventricular end diastolic pressure more than 9 mmHg in 73 cases (68%). The left ventricular end diastolic pressure was above 13 mmHg in 58 cases (54%). 相似文献
28.
Dash Bodhisattva Rup Suvendu Mohapatra Anjali Majhi Banshidhar Swamy M. N. S. 《Multimedia Tools and Applications》2018,77(12):15221-15250
Multimedia Tools and Applications - This paper proposes an ensemble of multi-layer perceptron (MLP) networks for side information (SI) generation in distributed video coding (DVC). In the proposed... 相似文献
29.
Wireless Networks - In the cooperative cognitive radio networks (CRN), often secondary user (SU) relays the information of primary user (PU) as a rewarding relay to improve diversity gain of PU... 相似文献
30.
Siddharth Panda Prasanta Kumar Majhi Annamalai Anandan Anumalla Mahender Sumanth Veludandi Debendranath Bastia Suresh Babu Guttala Shravan Kumar Singh Sanjoy Saha Jauhar Ali 《International journal of molecular sciences》2021,22(11)
The underground reserve (root) has been an uncharted research territory with its untapped genetic variation yet to be exploited. Identifying ideal traits and breeding new rice varieties with efficient root system architecture (RSA) has great potential to increase resource-use efficiency and grain yield, especially under direct-seeded rice, by adapting to aerobic soil conditions. In this review, we tried to mine the available research information on the direct-seeded rice (DSR) root system to highlight the requirements of different root traits such as root architecture, length, number, density, thickness, diameter, and angle that play a pivotal role in determining the uptake of nutrients and moisture at different stages of plant growth. RSA also faces several stresses, due to excess or deficiency of moisture and nutrients, low or high temperature, or saline conditions. To counteract these hindrances, adaptation in response to stress becomes essential. Candidate genes such as early root growth enhancer PSTOL1, surface rooting QTL qSOR1, deep rooting gene DRO1, and numerous transporters for their respective nutrients and stress-responsive factors have been identified and validated under different circumstances. Identifying the desired QTLs and transporters underlying these traits and then designing an ideal root architecture can help in developing a suitable DSR cultivar and aid in further advancement in this direction. 相似文献