286 research outputs found
Modular frames for Hilbert C*-modules and symmetric approximation of frames
We give a comprehensive introduction to a general modular frame construction
in Hilbert C*-modules and to related modular operators on them. The Hilbert
space situation appears as a special case. The reported investigations rely on
the idea of geometric dilation to standard Hilbert C*-modulesover unital
C*-algebras that admit an orthonormal Riesz basis. Interrelations and
applications to classical linear frame theory are indicated. As an application
we describe the nature of families of operators {S_i} such that SUM_i
S*_iS_i=id_H, where H is a Hilbert space. Resorting to frames in Hilbert spaces
we discuss some measures for pairs of frames to be close to one another. Most
of the measures are expressed in terms of norm-distances of different kinds of
frame operators. In particular, the existence and uniqueness of the closest
(normalized) tight frame to a given frame is investigated. For Riesz bases with
certain restrictions the set of closetst tight frames often contains a multiple
of its symmetric orthogonalization (i.e. L\"owdin orthogonalization).Comment: SPIE's Annual Meeting, Session 4119: Wavelets in Signal and Image
Processing; San Diego, CA, U.S.A., July 30 - August 4, 2000. to appear in:
Proceedings of SPIE v. 4119(2000), 12 p
Purification of quantum trajectories
We prove that the quantum trajectory of repeated perfect measurement on a
finite quantum system either asymptotically purifies, or hits upon a family of
`dark' subspaces, where the time evolution is unitary.Comment: 10 page
Demonstration of Feeding Vehicle-Integrated Photovoltaic-Converted Energy into the High-Voltage On-Board Network of Practical Light Commercial Vehicles for Range Extension
The setting up of a practical electrically driven light commercial demonstration vehicle with integrated photovoltaics (PV) is reported. The demonstrator vehicle is equipped with 15 modules based on the crystalline Si/amorphous Si heterojunction technology. The nominal total peak power under standard testing conditions is 2180 Wp. Specifically, the PV-converted energy is fed into the high-voltage (HV; 400 V) board-net for a utilization of the large capacity of the HV battery and thus for direct range extension. The demonstrator vehicle is equipped with irradiation, wind, temperature, magnetic, and global positioning system sensors. Irradiation and temperature as well as the energy flows from modules, maximum power point trackers (MPPTs), low-voltage buffer battery to HV battery via DC/DC, and from the HV battery to the loads during an exemplarily test drive day (May 31, 2021) are monitored. The range extension obtained at this day on our test route (51° 59âČ N, 9° 31âČ E) was 36 km, the corresponding CO2 savings account for â2.3 kg. The chain efficiency of the electronic components from the input side of the MPPTs to the HV output side of the DC/DC was 68.6%, whereas the DC/DC itself has an average efficiency of 90%. © 2021 The Authors. Solar RRL published by Wiley-VCH Gmb
Investigation of Effective Factors on Vehicles Integrated Photovoltaic (VIPV) Performance: A Review
Integrating photovoltaic technology has undergone significant development in recent years, owing to its manifold advantages. One of the most recent domains where this technology has found application is within the transportation sector. The utilization of this technology possesses the potential to initiate a new revolution in transportation by enhancing the range and reducing fuel consumption in vehicles. The performance of these systems is influenced by numerous factors, which have been thoroughly examined in this study. These factors have been categorized into three broad groups: installation site, solar cell characteristics, and environmental conditions. It is important to note that these conditions are inherently interdependent, so this study reveals that the radiation incident on the roof of a van can be 1.09â3.85 times greater than the radiation incident on its sides, according to varying meteorological conditions and different seasons. The current research serves as a valuable foundation for future investigations in this field, offering a targeted and practical overview of the work conducted thus far and summarizing the current state of research
Here comes the sun: the promise of solar energy
George Harrison, the youngest Beatle, wrote the classic âHere Comes the Sunâ in 1969 after spending a glorious day walking around his friend Eric Claptonâs garden. Today, Harrisonâs refrain, âAnd I say, âItâs All rightâ,â accords well with a solar power industry that has grown more than 30 percent in the past six years and received tax-favorable legislative approval in 2006
PV Charging and Storage for Electric Vehicles
Electric vehicles are only âgreenâ as long as the source of electricity is âgreenâ as well. At the same time, renewable power production suffers from diurnal and seasonal variations, creating the need for energy storage technology. Moreover, overloading and voltage problems are expected in the distributed network due to the high penetration of distributed generation and increased power demand from the charging of electric vehicles. The energy and mobility transition hence calls for novel technological innovations in the field of sustainable electric mobility powered from renewable energy. This Special Issue focuses on recent advances in technology for PV charging and storage for electric vehicles
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