The genetic algorithm is an efficient optimization tool for its independence of problems, intrinsic parallelism and inherent learning capacity;however, it has some disadvantages such as slow convergence and prematurit...
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The genetic algorithm is an efficient optimization tool for its independence of problems, intrinsic parallelism and inherent learning capacity;however, it has some disadvantages such as slow convergence and prematurity. A quantum genetic algorithm (QGA), is proposed based on the combination of the quantum theory with the evolutionary theory. By adopting the qubit chromosome as a representation, QGA can represent a linear superposition of solutions due to its probabilistic representation. The random observation simulating the quantum collapse can bring diverse individuals, and the evolution of quantum chromosome can pilot the evolution. So it has better diversity than the classical genetic algorithm. Rapid convergence and good global search capacity characterize the performance of QGA. The paper proves the global convergence of the QGA, and some simulation experiments show its superiority over other algorithms.
Hafnium oxide films were grown on SOI (silicon-on-insulator) materials by electron beam evaporation of HfO2 target and followed by rapid annealing in nitrogen (600°C, 300s). In order to study the change of comp.s...
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Hafnium oxide films were grown on SOI (silicon-on-insulator) materials by electron beam evaporation of HfO2 target and followed by rapid annealing in nitrogen (600°C, 300s). In order to study the change of comp.sition and structure of the samples before and after annealing, glancing-angle X-ray diffraction (GAXRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscope (HRTEM) were used to investigate the samples. Analysis results showed that hafnium oxide films became polycrystalline phase in monoclinic structure from amorphous phase and the O/Hf ratio approached to stoichiometric proportion, i.e., 2 after annealing. In the end, spreading resistance profiles (SRP) showed excellent dielectric properties for hafnium oxide films whenever amorphous or polycrystalline.
Gather-and-Sift based on DIXON resultant is an effective algorithm for solving nonlinear algebraic equation system. This algorithm is not applied widely because it requires interacting of the expert. The author studie...
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Gather-and-Sift based on DIXON resultant is an effective algorithm for solving nonlinear algebraic equation system. This algorithm is not applied widely because it requires interacting of the expert. The author studied this algorithm and made two improvements on programming skills in order to solve the problem of lower efficiency when the middle results of DPS are not satisfied. The author developed an automatic software, GAS, by applying the skills. GAS has higher efficiency in solving nonlinear algebraic equation system without any interacting in the whole processing and can be used in real engineering comp.ting.
Based on the optical orthogonal codes, a method for constructing irregular LDPC (low-density parity check) codes was presented. These LDPC codes are quasi-cyclic codes and can be encoded with low comp.exity with a lin...
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Based on the optical orthogonal codes, a method for constructing irregular LDPC (low-density parity check) codes was presented. These LDPC codes are quasi-cyclic codes and can be encoded with low comp.exity with a linear relationship to code length. These codes have Tanner graphs free of 4-cycles. They perform well with the sum-product iterative decoding. comp.red with random codes and regular LDPC codes based on the optical orthogonal codes with similar parameters, they have decoding performance gains respectively about 0.3 and 0.15 dB when bit error rate is 10-5.
The recent results of research in the field of statistical theory were applied to potential analysis of enhanced oil recovery (EOR). The applications of group method of data handling (GMDH), improved error back propag...
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The recent results of research in the field of statistical theory were applied to potential analysis of enhanced oil recovery (EOR). The applications of group method of data handling (GMDH), improved error back propagation (BP) artificial neutral network and support vector machine (SVM) to enhanced oil recovery were discussed. The comp.rison of the three methods indicates that SVM has both the universality and the extendibility of a model when the samples are very limited. A small error from an effective training set can guarantee a small error for the corresponding independent testing set. SVM shows a good prospect of its application.
Wireless networks are inherently limited by the bandwidth constraint. MAC protocols for Wireless Local Area Networks (WLANs) play the important role of arbitrating and statistically multiplexing the transmission reque...
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Wireless networks are inherently limited by the bandwidth constraint. MAC protocols for Wireless Local Area Networks (WLANs) play the important role of arbitrating and statistically multiplexing the transmission requests of various stations contending to access the channel. The performance of IEEE 802.11 degrades in Ad hoc networks because of the presence of hidden and exposed terminals. To counter these problems, we propose a new MAC protocol called Interleaved Carrier Sense Multiple Access (ICSMA) Protocol for Ad hoc wireless networks. The performance of ICSMA was comp.red with single channel 802.11 MAC protocol and with 802.11 MAC protocol over two channels with half the bandwidth through extensive simulation studies. Results show that ICSMA performs better with respect to throughput, access delay, throughput fairness, and delay fairness when comp.red with IEEE 802.11.
In this paper, we describe a framework that facilitates automatic generation of optimizers. The framework consists of a specification language to describe optimizations and a tool to generate optimizers from these spe...
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ISBN:
(纸本)0889863490
In this paper, we describe a framework that facilitates automatic generation of optimizers. The framework consists of a specification language to describe optimizations and a tool to generate optimizers from these specifications. The framework provides a test-bed for verifying correctness of various optimizations and studying the interactions between them, and thus deciding the order in which they shall be applied to achieve maximum benefit.
A test coverage analyzer speeds up the software testing process and minimizes the cost. The development steps for most of the test coverage analyzers are similar for any block structured language. This indicates the p...
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ISBN:
(纸本)0889863946
A test coverage analyzer speeds up the software testing process and minimizes the cost. The development steps for most of the test coverage analyzers are similar for any block structured language. This indicates the potential for a generic technique for test coverage analyzer development. Most of the commonly used coverage like path coverage, branch coverage, block coverage, function coverage, loop coverage, deal with the control structure representation of the program. We can generate report for these coverages with the help of block trace and the control structure representation. The processing done on control structure remains same for generating a coverage report for all block structured language. Control structure representation of programs can easily be generated from the grammar of the language inst.umented for block coverage. Using the control structure representation and the block trace generated from the block coverage analysis, our technique can be used to generate report for coverage like path coverage, block coverage, branch coverage, loop coverage, function coverage, etc.. We have implemented our technique to generate the report for path coverage. The results had shown a great reduction in development time for path coverage analyzer for a block structured language. After developing the reporting mechanism for all other coverage also (using our technique), one need not develop all these coverage analyzers for a new block structured language. Thus, only the block coverage analyzer and control structure generator are to be developed for a new block structured language.
Existing multicast routing protocols for Mobile Ad hoc Networks can be broadly classified into two categories, tree based protocols and mesh based protocols. Mesh based protocols have high packet delivery ratio comp.r...
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Existing multicast routing protocols for Mobile Ad hoc Networks can be broadly classified into two categories, tree based protocols and mesh based protocols. Mesh based protocols have high packet delivery ratio comp.red to tree based protocols, but incur more control overhead. The packet delivery ratio of tree based protocols decreases with increasing mobility. This is due to the occurrence of frequent tree breaks and lack of proper tree maintenance mechanisms. These tree breaks result in frequent flooding of JoinQuery packets by the multicast group member nodes which try to get re-connected to the tree. These broadcast packets collide with data packets and reduce the efficiency of the protocol. We propose an efficient protocol which we call as Preferred Link Based Multicast protocol (PLBM). PLBM uses a preferred link approach for forwarding JoinQuery packets. A subset of neighbors of a node are selected using a preferred link based algorithm. These nodes, termed as preferred nodes, are only eligible for further forwarding of JoinQuery packets. We also propose a quick link break detection mechanism that locally repairs broken links. Simulation results show that our protocol performs better than other existing multicast protocols in terms of packet delivery ratio and control overhead.
Consider a synchronous network of n players, each with a local input. The goal of distributed consensus is to globally agree on one of the valid inputs even if some non-trivial sub-set of the players are faulty. By va...
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ISBN:
(纸本)9781581137088
Consider a synchronous network of n players, each with a local input. The goal of distributed consensus is to globally agree on one of the valid inputs even if some non-trivial sub-set of the players are faulty. By valid input, we mean the input of any non-faulty player. Extant results in Byzantine agreement literature capture the behaviour of faulty players in an "all-or-nothing" fashion, For inst.nce, a (Byzantine) faulty player is comp.etely unconstrained and could behave differently with different players. This leads to a gross underestimation of the achievable fault-tolerance. In this work, we propose a fault-model that considerably improves the estimation of fault-tolerance and helps capture real-life scenarios better. For inst.nce, if two (honest) players were part of the same LAN (which is essentially a broadcast network), it is impossible for a external faulty player to behave differently with these two players (though the faulty player may behave with "equal" malice with both these players!). Among our results, we introduce the sectional fault-model that is more general and can capture practical scenarios not captured by any extant model. We provide a comp.ete characterization of the tolerable faults and present efficient protocols to achieve consensus. We remark that the results of this paper strictly generalize the extant characterizations of fault-tolerance. For example, consider a network of four players P1,P1,P3 and P 4, under the corrupting influence of a Byzantine adversary given by the adversary structure A = {(P1,P2),(P2,P 3),(P4)}. Agreement is impossible in such a scenario, since the three sets from A cover the player set. However, it would be evident from our results that consensus in the above scenario was indeed possible if (and only if) the players P1, P3 and P4 belonged to a single LAN in the network!
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