Full video format focal plane array (FPA) modules with up to 640 x 512 pixels have been developed for high resolution imaging applications in either mercury cadmium telluride (MCT) mid wave (MWIR) infrared (IR) or pla...
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ISBN:
(纸本)0819436542
Full video format focal plane array (FPA) modules with up to 640 x 512 pixels have been developed for high resolution imaging applications in either mercury cadmium telluride (MCT) mid wave (MWIR) infrared (IR) or platinum silicide (PtSi) and quantum well infrared photodetector (QWIP) technology as low cost alternatives to MCT for high performance IR imaging in the MWIR or long wave spectral band (LWIR). For the QWIP's, a new photovoltaic technology was introduced for improved NETD performance and higher dynamic range. MCT units provide fast frame rates >100Hz together with state of the art thermal resolution NETD < 20mK for short snapshot integration times of typically 2ms. PtSi and QWIP modules are usually operated in a rolling frame integration mode with frame rates of 30-60Hz and provide thermal resolutions of NETD < 80mK for PtSi and NETD < 20mK for QWIP, respectively. Due to the lower quantum efficiency compared to MCT, however, the integration time is typically chosen to be as long 10-20ms. The heat load of the integrated detector cooler assemblies (IDCAs) could be reduced to an amount as low, that a 1W split linear cooler provides sufficient cooling power to operate the modules - including the QWIP with 60K operation temperature - at ambient temperatures up to 65C. Miniaturized command/control electronics (CCE) available for all modules provide a standardized digital interface, with 14 bit analogue to digital conversion for state of the art correctability, access to highly dynamic scenes without any loss of information and simplified exchangeability of the units. New modular image processing hardware platforms and software for image visualization and nonuniformity correction including scene based self learning algorithms had to bee developed to accomplish for the high data rates of up to 18M pixels/s with 14 bit deep data, allowing to take into account non linear effects to access the full NETD by accurate reduction of residual fixed pattern noise.
We consider a quantum computational algorithm that can be used to determine (probabilistically) how close a given signal is to one of a set of previously observed signals stored in the state of a quantum neurocomputio...
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We consider a quantum computational algorithm that can be used to determine (probabilistically) how close a given signal is to one of a set of previously observed signals stored in the state of a quantum neurocomputional machine. The realization of a new quantum algorithm for factorization of integers by Shor and its implication to cryptography has created a rapidly growing field of investigation. Although no physical realization of a quantum computer is available, a number of software systems simulating a quantum computation process exist. In light of the rapidly increasing power of desktop computers and their ability to carry out these simulations, it is worthwhile to investigate possible advantages as well as realizations of quantumalgorithms in signal processing applications. The algorithm presented offers a glimpse of the potential of this approach. Neural networks (NN) provide a natural paradigm for parallel and distributed processing of a wide class of signals. Neural networks within the context of classical computation have been used for approximation and classification tasks with some success. We propose a model for quantum neurocomputation (QN) and explore some of its properties and potential applications to signal processing in an information theoretic context.
We discuss some seemingly paradoxical yet valid effects of quantum physics in informationprocessing. Firstly, we argue that the act of "doing nothing" on part of an entangled quantum system is a highly non-...
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ISBN:
(纸本)354065514X
We discuss some seemingly paradoxical yet valid effects of quantum physics in informationprocessing. Firstly, we argue that the act of "doing nothing" on part of an entangled quantum system is a highly non-trivial operation and that it is the essential ingredient underlying the computational speedup in the known quantumalgorithms. Secondly, we show that the watched pot effect of quantum measurement theory gives the following novel computational possibility: suppose that we have a quantum computer with an on/off switch, programmed ready to solve a decision problem. Then (in certain circumstances) the mere fact that the computer would have given the answer if it were run, is enough for us to learn the answer, even though the computer is in fact not run.
Introduced by Fuji Photo Film Japan in the early 1980s, computed radiography (CR) technology has developed considerably since then to become the mature widely installed technology it is today (about 7500 systems world...
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Introduced by Fuji Photo Film Japan in the early 1980s, computed radiography (CR) technology has developed considerably since then to become the mature widely installed technology it is today (about 7500 systems worldwide). Various mammographic examinations require high performance results to which CR complies on demand or following some procedures such as geometrical magnification carried out during the examination. The basic CR principles and digital image processing as well as technical improvements are detailed in this study, which also includes a synthesis of the articles on CR mammographic applications referenced in the bibliography, focusing on strong points, limits and current methods of surpassing these limits. New CR technology development perspectives in mammography and computed assisted diagnosis (CAD) algorithms will allow wider use of this method in the near future. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.
When the 4-state or the 6-state protocol of quantum cryptography is carried out on a noisy quantum channel, then the raw key has to be processed to reduce the information of a spy down to an arbitrarily low value, pro...
When the 4-state or the 6-state protocol of quantum cryptography is carried out on a noisy quantum channel, then the raw key has to be processed to reduce the information of a spy down to an arbitrarily low value, providing Alice and Bob with a secret key. In principle, quantumalgorithms as well as classical algorithms can be used for this processing. A natural question is: Up to which error rate on the raw key is a secret-key agreement at all possible? Under the assumption of incoherent eavesdropping, we find that the quantum and classical limits are precisely the same: As long as Alice and Bob share some entanglement, both quantum and classical protocols provide secret keys.
We discuss some seemingly paradoxical yet valid effects of quantum physics in informationprocessing. Firstly, we argue that the act of "doing nothing" on part of an entangled quantum system is a highly non-...
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We discuss some seemingly paradoxical yet valid effects of quantum physics in informationprocessing. Firstly, we argue that the act of "doing nothing" on part of an entangled quantum system is a highly non-trivial operation and that it is the essential ingredient underlying the computational speedup in the known quantumalgorithms. Secondly, we show that the watched pot effect of quantum measurement theory gives the following novel computational possibility: suppose that we have a quantum computer with an on/off switch, programmed ready to solve a decision problem. Then (in certain circumstances) the mere fact that the computer would have given the answer if it were run, is enough for us to learn the answer, even though the computer is in fact not run. (C) 1999 Elsevier Science Ltd. All rights reserved.
quantum networks are created to implement fundamental quantum communication protocols and for distributed quantum computation. Beyond quantuminformationprocessing with internal atomic states and photons serving as q...
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quantum networks are created to implement fundamental quantum communication protocols and for distributed quantum computation. Beyond quantuminformationprocessing with internal atomic states and photons serving as qubits, an algorithms for continuous quantum variables are also investigated. A recent example is the realization of quantum teleportation for the quadrature amplitudes of a beam of light. It utilizes squeezed-state entanglement to achieve unconditional quantum teleportation.
Summary form only given. quantum mechanics offers the information scientist a new rich resource, which is only recently being tapped to allow for secure communication in the form of quantum cryptography, and for treme...
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Summary form only given. quantum mechanics offers the information scientist a new rich resource, which is only recently being tapped to allow for secure communication in the form of quantum cryptography, and for tremendous parallelism in quantuminformationprocessing and computing. I will describe developments and prospects for each. quantum cryptography has already advanced beyond the research laboratory to become a realizable technology with proven secret key distribution for encryption. quantum computing, although at an earlier stage of development has been recognized as a major new development in physics, enables us (if a quantum computer is realizable) to attack problems previously thought to be too complex for normal computation in a reasonable time. Examples of quantumalgorithms involving this kind of advantage are Shor's for fast factorization (in itself a threat to secure communication) and Grover's for database searching. I will discuss the ways quantum mechanics allow such a speed-up, stressing how quantum entanglement is the key resource being exploited, and how quantum gates, networks, and the processors may be implemented in a realistically noisy environment. Simple demonstrators have already been built, and I will discuss prospects for future realization of large-scale processors.
The paper presents a general model for estimating access times of serpentine tape drives. The model is used to schedule I/O requests in order to minimize the total access time. We propose a new scheduling algorithm, M...
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The paper presents a general model for estimating access times of serpentine tape drives. The model is used to schedule I/O requests in order to minimize the total access time. We propose a new scheduling algorithm, Multi-Pass Scan Star (MPScan*), which makes good utilization of the streaming capability of the tape drive and avoids the pitfalls of naive multi-pass scan algorithms and greedy algorithms like Shortest Locate Time First. The performance of several scheduling algorithms have been simulated for problem sizes up to 2048 concurrent I/O requests. For scheduling of two to 1000 I/O requests, MPScan* gives equal or better results than any other algorithm, and provides up to 85 percent reduction of the total access time. All results have been validated by extensive experiments on Tandberg MLRI and quantum DLT2000 drives.
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