1,721,156 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Radiation-Induced Short Channel (RISCE) and Narrow Channel (RINCE) Effects in 65 and 130 nm MOSFETs
No full textThe behavior of transistors in commercial-grade complementary metal-oxide semiconductor technologies in the 65 and 130 nm nodes has been explored up to a total ionizing dose of 1 Grad. The large dose tolerance of the thin gate oxide is confirmed, but defects in the spacer and STI oxides have a strong effect on the performance of the transistors. A radiation-induced short channel effect is traced to charge trapping in the spacers used for drain engineering, while a radiation-induced narrow channel effect is due to defect generation in the lateral isolation oxide (STI). These strongly degrade the electrical characteristics of short and narrow channel transistors at high doses, and their magnitude depends on the applied bias and temperature during irradiation in a complex way
Channel Hot Carrier Stress on Irradiated 130-nm NMOSFETs
No full textWe investigate how X-ray exposure impact the long term reliability of 130-nm NMOSFETs as a function of device geometry and irradiation bias conditions. This work focuses on electrical stresses on n-channel MOSFETs performed after irradiation with X-ray up to 136 Mrad(SiO2) in different bias conditions. Irradiation is shown to negatively affect the degradation during subsequent hot carrier injection. Increasing the bias during irradiation slightly reduces the impact on following electrical stress in core MOSFETs. Through device simulations, we attribute these effects to an enhanced impact ionization at the bulk-STI interfaces due to radiation-induced trapped charge and defects
Regulated Resonant Switched-Capacitor Point-of-Load Converter Architecture and Modeling
No full textThis article presents a novel control system for a regulated resonant switched-capacitor point-of-load converter, together with its steady-state and small-signal analyses. The output voltage is regulated through a combined frequency/phase shift on-chip controller that operates, thanks to a zero-crossing detector for the tank current. By using such a control technique, voltage regulation can be achieved for a wide range of conversion ratios. Different operation modes are adopted to maximize the efficiency at every load condition. A prototype based on an ASIC developed in a 130-nm CMOS technology has been designed, which achieves the 2.5 to 0.8-1.35 V conversion and supplies up to 3 A. The external resonant tank is composed of a 12 nH air-core inductor and a 4.7 mu F capacitor in a 0805 package, achieving high power density. The converter efficiency is demonstrated to be similar to that of an integrated buck converter designed for the same application, whereas the inductor size is reduced by a factor of eight
Channel Hot Carrier Stress on Irradiated 130-nm NMOSFETs
No full textWe investigate how X-ray exposure impact the long term reliability of 130-nm NMOSFETs as a function of device geometry and irradiation bias conditions. This work focuses on electrical stresses on n-channel MOSFETs performed after irradiation with X-ray up to 136 Mrad(SiO2) in different bias conditions. Irradiation is shown to negatively affect the degradation during subsequent hot carrier injection. Increasing the bias during irradiation slightly reduces the impact on following electrical stress in core MOSFETs. Through device simulations, we attribute these effects to an enhanced impact ionization at the bulk-STI interfaces due to radiation-induced trapped charge and defects
Degradation induced by X-ray Irradiation and Channel Hot Carrier Stresses in 130-nm NMOSFETs With Enclosed Layout
No full textWe present new experimental results about channel hot carrier degradation of enclosed layout transistors as a function of previous accumulated total ionizing dose, stress temperature, and transistor geometry. We show that the parametric degradation follows a power law, whose exponent is higher than in conventional open layout transistors, possibly due to a different diffusion geometry of hydrogen. Through physical simulation we attribute this effect to the electric field at the device corners, which leads to a non-uniform impact ionization. Previous irradiation reduces the channel hot carrier degradation in MOSFETs with 5.2-nm gate oxide, while having a minor influence with 2.2-nm gate dielectric
Radiation Effects on the 1/f Noise of Field-Oxide Field Effect Transistors
No full textLow-frequency (1/f) noise measurements were performed at room temperature as a function of gate bias on Field-Oxide Field Effect Transistors (FOXFETs) that were irradiated with 10-keV X-rays and then annealed at room temperature. The resulting oxide-trap and interface-trap charge densities were estimated by the midgap charge separation technique. Some devices also were exposed to 85% relative humidity at 130 degrees C for three days after irradiation and annealing. Effective border trap densities were estimated from noise measurements in each case. The noise magnitude increases after irradiation and decreases first during annealing and then even more significantly after moisture exposure. The post-humidity-exposure noise for the irradiated devices is well below the pre-irradiation noise for these devices and experimental conditions. The increased noise due to irradiation is attributed to 0 vacancies and hydrogen bridge (Si-H-Si) defects in the near-interfacial field oxide. The reduction in noise with room-temperature annealing and humidity exposure is due to a combination of thermal and tunnel annealing processes and defect passivation reactions involving water
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Simulating Floating Head Pressure Control with Artificial Intelligence
Full text linkIn this work, we model with artificial intelligence techniques one of the most used solutions for energy saving in the field of refrigeration. This solution, called floating head pressure control, allows for the optimum pressure condensation depending on the working environment, thus increasing the overall efficiency of the plant. Usually, these mechanisms are controlled by algorithms that are stored in the control memory of the chillers. Under certain environmental conditions, the optimal temperature and condensation pressure fluctuate with the environmental temperature. Thus, the absorbed electricity depends on the working parameters fixed by the control system of the chiller. Results in energy savings in these terms could grow as the external temperature decreases. The problem addressed in this work regards standard floating head pressure control (FHPC) systems that do not combine working environmental factors with the conditions of the machine and historical data because they are implemented adopting static models. We provide evidence about the potential of machine learning models in predicting the velocity of fans in order to adjust their load based on environmental factors and the conditions of the machine. A good setting of fan velocity will result in lower energy consumption. To do that we analyzed and implemented machine learning algorithms to provide instruments that support the operation of the chiller, enabling the floating head pressure control mode in the control system of the machine, during its process. We performed an empirical evaluation on both synthetic and real data to assess the quality of our proposal. Synthetic data are produced by an industrial software that simulates the behavior of chillers, while real-world data is collected from a commercial chiller. The results show that machine learning approaches are able to approximate real data getting errors that are 5 times smaller than the errors committed by the system that is now adopted. All the source code as well as the datasets will be made available online after the review process
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