11,524 research outputs found
A Holistic Education Approach for Assessing Business Programs
Providing business students with a holistic education is essential for developing professionals who are equally proficient in their use of hard and soft skills and capable of applying various concepts from different disciplines to create innovative solutions. To understand if students are learning the content that a holistic business education is intended to deliver, a case study of business program assessment was conducted. Specifically, this research is focused on an assessment of business students from a comprehensive regional institution of higher education to determine if the business program has incorporated appropriate assessment strategies in order to meet the expectations of a holistic education including meeting student learning outcomes defined by the AACSB International accredited program
Ab initio study of the formation of transparent carbon under pressure
A body-centered tetragonal carbon (bct-Carbon) allotrope has been predicted
to be a transparent carbon polymorph obtained under pressure. The structural
transition pathways from graphite to diamond, M-Carbon, and bct-Carbon are
simulated and the lowest activation barrier is found for the graphite-bct
transition. Furthermore, bct-Carbon has higher shear strength than diamond due
to its perpendicular graphene-like structure. Our results provide a possible
explanation for the formation of a transparent carbon allotrope via the cold
compression of graphite. We also verify that this allotrope is hard enough to
crack diamond.Comment: [email protected] or [email protected]
Model Predictive Control for Dual Active Bridge in Naval DC Microgrids Supplying Pulsed Power Loads Featuring Fast Transition and Online Transformer Current Minimization
Pulsed power loads (PPLs) are commonly incorporated in medium voltage dc microgrids on naval vessels. To mitigate their detrimental effects, dedicated energy storage systems can be installed and their converters need to have excellent disturbance rejection capability. To facilitate this objective, a moving-discretized-control-set model-predictive-control (MDCS-MPC) is proposed in this letter and applied on a dual-active-bridge converter. Fixed switching frequency is maintained, enabling easy passive components design. The proposed MDCS-MPC has a small number of calculating points in each switching period, which enables the implementation in standard commercial control platforms. The operating principle of the MDCS-MPC is introduced in development of a cost function that, on one hand, provides stiff voltage regulation; on the other hand, minimizes transformer current stress online. Theoretical claims are verified on a 20 kHz 1 kW dual active bridge
Berry phase correction to electron density of states in solids
Liouville's theorem on the conservation of phase space volume is violated by
Berry phase in the semiclassical dynamics of Bloch electrons. This leads to a
modification of the phase space density of states, whose significance is
discussed in a number of examples: field modification of the Fermi-sea volume,
connection to the anomalous Hall effect, and a general formula for orbital
magnetization. The effective quantum mechanics of Bloch electrons is also
sketched, where the modified density of states plays an essential role.Comment: Minor revision. Journal info updat
Model-Predictive-Control for Dual-Active-Bridge Converters Supplying Pulsed Power Loads in Naval DC Micro-grids
Pulsed-Power-Loads (PPLs) are becoming prevalent in medium-voltage naval DC micro-grids. To alleviate their effects on the system, energy storages are commonly installed. For optimal performance, their interface converters need to have fast dynamics and excellent disturbance rejection capability. Moreover, these converters often need to have voltage transformation and galvanic isolation capability since common energy storage technologies like batteries and super-caps are typically assembled with low voltage strings. In order to address these issues, a Moving-Discretized-Control-Set Model-Predictive-Control (MDCS-MPC) is proposed in this paper and applied on a Dual-Active-Bridge converter. Fixed switching frequency is maintained, enabling easy passive components design. The proposed MDCS-MPC has a reduced prediction horizon, which allows low computational burden. The operating principle of the MDCS-MPC is introduced in development of a cost function that provides stiff voltage regulation. Resonance damping and sampling noise resistance can also be achieved with the proposed cost function. An adaptive step is introduced to enable fast transition. Assessments on the performance of the proposed MDCS-MPC are conducted. Comparisons with other control methods are also provided. Experimental validations on a 300V/300V 20kHz 1kW Dual-Active-Bridge converter are carried out to verify the theoretical claims. Index Terms-Isolated DC/DC converter, Dual-Active-Bridge (DAB), Model Predictive Control (MPC)
COVID-19 and Computer Audition: An Overview on What Speech & Sound Analysis Could Contribute in the SARS-CoV-2 Corona Crisis
At the time of writing, the world population is suffering from more than
10,000 registered COVID-19 disease epidemic induced deaths since the outbreak
of the Corona virus more than three months ago now officially known as
SARS-CoV-2. Since, tremendous efforts have been made worldwide to counter-steer
and control the epidemic by now labelled as pandemic. In this contribution, we
provide an overview on the potential for computer audition (CA), i.e., the
usage of speech and sound analysis by artificial intelligence to help in this
scenario. We first survey which types of related or contextually significant
phenomena can be automatically assessed from speech or sound. These include the
automatic recognition and monitoring of breathing, dry and wet coughing or
sneezing sounds, speech under cold, eating behaviour, sleepiness, or pain to
name but a few. Then, we consider potential use-cases for exploitation. These
include risk assessment and diagnosis based on symptom histograms and their
development over time, as well as monitoring of spread, social distancing and
its effects, treatment and recovery, and patient wellbeing. We quickly guide
further through challenges that need to be faced for real-life usage. We come
to the conclusion that CA appears ready for implementation of (pre-)diagnosis
and monitoring tools, and more generally provides rich and significant, yet so
far untapped potential in the fight against COVID-19 spread
Photoproduction and Radiative Decay of Spin 1/2 and 3/2 Pentaquarks
We study photoproduction and radiative decays of pentauqarks paying
particular attention to the differences between spin-1/2 and spin-3/2, positive
and negative parities of pentaquarks. Detailed study of these processes can not
only give crucial information about the spin, but also the parity of
pentaquarks.Comment: 14 pages, 7 figure
Heavy quarkonium 2S states in light-front quark model
We study the charmonium 2S states and , and the bottomonium
2S states and , using the light-front quark model and the
2S state wave function of harmonic oscillator as the approximation of the 2S
quarkonium wave function. The decay constants, transition form factors and
masses of these mesons are calculated and compared with experimental data.
Predictions of quantities such as Br are made. The
2S wave function may help us learn more about the structure of these heavy
quarkonia.Comment: 5 latex pages, final version for journal publicatio
Spin-Fluctuation-Induced Non-Fermi-Liquid Behavior with suppressed superconductivity in LiFeCoAs
A series of LiFeCoAs compounds with different Co concentrations
have been studied by transport, optical spectroscopy, angle-resolved
photoemission spectroscopy and nuclear magnetic resonance. We observed a Fermi
liquid to non-Fermi liquid to Fermi liquid (FL-NFL-FL) crossover alongside a
monotonic suppression of the superconductivity with increasing Co content. In
parallel to the FL-NFL-FL crossover, we found that both the low-energy spin
fluctuations and Fermi surface nesting are enhanced and then diminished,
strongly suggesting that the NFL behavior in LiFeCoAs is induced
by low-energy spin fluctuations which are very likely tuned by Fermi surface
nesting. Our study reveals a unique phase diagram of LiFeCoAs
where the region of NFL is moved to the boundary of the superconducting phase,
implying that they are probably governed by different mechanisms.Comment: 10 pages, 11 figure
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