Mac错误代码的含义

Ｍａｃ错误代码的含义程红兵你可能遇到过这样的情况，开机后出现黑屏，当中有一个“悲伤的Ｍａｃ”图标，其下是一些代码。那么，这些代码是什么含义？机器出了什么问题？具体问题要具体分析。如果Ｍａｃ可由另一系统盘启动，则问题可能出在原启动盘的系统软件上。如果先...

一阵清风徐来——统一格式的民用摄录机DVC

录像机和摄像机除去电视制式外,其本身的记录方式和盒带类型也是庞杂繁多,模拟和数字的各有七八种,光罗列名称就会令人目眩,软件的交流也就大成问题。

Numerical investigation on permeability evolution behavior of rock by an improved flow-coupling algorithm in particle flow code

Permeability is a vital property of rock mass, which is highly affected by tectonic stress and human engineering activities. A comprehensive monitoring of pore pressure and flow rate distributions inside the rock mass is very important to elucidate the permeability evolution mechanisms, which is difficult to realize in laboratory, but easy to be achieved in numerical simulations. Therefore, the particle flow code （PFC）, a discrete element method, is used to simulate permeability behaviors of rock materials in this study. Owe to the limitation of the existed solid-fluid coupling algorithm in PFC, an improved flow-coupling algorithm is presented to better reflect the preferential flow in rock fractures. The comparative analysis is conducted between original and improved algorithm when simulating rock permeability evolution during triaxial compression, showing that the improved algorithm can better describe the experimental phenomenon. Furthermore, the evolution of pore pressure and flow rate distribution during the flow process are analyzed by using the improved algorithm. It is concluded that during the steady flow process in the fractured specimen, the pore pressure and flow rate both prefer transmitting through the fractures rather than rock matrix. Based on the results, fractures are divided into the following three types： I） fractures link to both the inlet and outlet, II） fractures only link to the inlet, and III） fractures only link to the outlet. The type I fracture is always the preferential propagating path for both the pore pressure and flow rate. For type II fractures, the pore pressure increases and then becomes steady. However, the flow rate increases first and begins to decrease after the flow reaches the stop end of the fracture and finally vanishes. There is no obvious pore pressure or flow rate concentration within type III fractures.

NEW ITERATIVE SUPER-TRELLIS DECODING WITH SOURCE A PRIORI INFORMATION FOR VLCS WITH TURBO CODES

A novel Joint Source and Channel Decoding (JSCD) scheme for Variable Length Codes (VLCs) concatenated with turbo codes utilizing a new super-trellis decoding algorithm is presented in this letter. The basic idea of our decoding algorithm is that source a priori information with the form of bit transition probabilities corresponding to the VLC tree can be derived directly from sub-state transitions in new composite-state represented super-trellis. A Maximum Likelihood (ML) decoding algorithm for VLC sequence estimations based on the proposed super-trellis is also described. Simu-lation results show that the new iterative decoding scheme can obtain obvious encoding gain especially for Reversible Variable Length Codes (RVLCs),when compared with the classical separated turbo decoding and the previous joint decoding not considering source statistical characteristics.

A new design criterion and construction method for space-time trellis codes based on classification of error events

The known design criterions of Space-Time Trellis Codes （STFC） on slow Rayleigh fading channel are rank, determinant and trace criterion. These criterions are not advantageous not onlv in operation but also in performance. With classifying the error events of STTC, a new criterion was presented on slow Rayleigh fading channels. Basod on the criterion, an effective and straighttbrward multi-step method is proposed to ennstruet codes with better performance. This method can reduce the computation of search to small enough. Simulation results show that the codes searched by computer have the same or even better performance than the repored codes.

VARIABLE NON-UNIFORM QUANTIZED BELIEF PROPAGATION ALGORITHM FOR LDPC DECODING

Non-uniform quantization for messages in Low-Density Parity-Check(LDPC)decoding canreduce implementation complexity and mitigate performance loss.But the distribution of messagesvaries in the iterative decoding.This letter proposes a variable non-uniform quantized Belief Propaga-tion(BP)algorithm.The BP decoding is analyzed by density evolution with Gaussian approximation.Since the probability density of messages can be well approximated by Gaussian distribution,by theunbiased estimation of variance,the distribution of messages can be tracked during the iteration.Thusthe non-uniform quantization scheme can be optimized to minimize the distortion.Simulation resultsshow that the variable non-uniform quantization scheme can achieve better error rate performance andfaster decoding convergence than the conventional non-uniform quantization and uniform quantizationschemes.

Constructing Non-binary Asymmetric Quantum Codes via Graphs

The theory of quantum error correcting codes is a primary tool for fighting decoherence and other quantum noise in quantum communication and quantum computation. Recently, the theory of quantum error correcting codes has developed rapidly and been extended to protect quantum information over asymmetric quantum channels, in which phase-shift and qubit-flip errors occur with different probabilities. In this paper, we generalize the construction of symmetric quantum codes via graphs (or matrices) to the asymmetric case, converting the construction of asymmetric quantum codes to finding matrices with some special properties. We also propose some asymmetric quantum Maximal Distance Separable (MDS) codes as examples constructed in this way.

A Monte Carlo Simulation of Radiation Damage of SiC and Nb Using JA-IPU Code

MC （Monte Carlo） simulation code, JA-IPU is used to study radiation damage of SiC irradiated to spallation neutron and AmBe neutron spectra. The code is based on the major physical processes of radiation damage on incorporation of atomic collision cascade and limited to 10 MeV neutron energy. A phenomenological relation for radiation swelling is also derived. Based on the calculation of swelling, DPA （displacement per atom）, defect production efficiency and effective threshold energy, Efff from the data of MC simulation, SiC is inferred to be a highly radiation resistant material when compared with Nb and Ni metals which are used in composition of several reactor steels. Experimental results of hill-hock density measured using AFM （atomic force microscopy）, also confirm radiation resistant behavior of SiC.

Efficient video downscaling transcoder from MPEG-2 to H.264

The new H.264 video coding standard achieves significantly higher compression performance than MPEG-2. As the MPEG-2 is popular in digital TV, DVD, etc., bandwidth or memory space can be saved by transcoding those streams into H.264 in these applications. Unfortunately, the huge complexity keeps transcoding from being widely used in practical applications. This paper proposes an efficient transcoding architecture with a smart downscaling decoder and a fast mode decision algorithm. Using the proposed architecture, huge buffering memory space is saved and the transcoding complexity is reduced. Performance of the proposed fast mode decision algorithm is validated by experiments.

SDCMA BLIND DETECTION IN FREQUENCY DOMAIN FOR MC DS-CDMA SYSTEMS

This paper proposes Steepest Decreasing Constant Modulus Algorithm （SDCMA） detection in frequency dornain for MultiCarrier Direct Sequence-Code Division Multiple Access （MC DS-CDMA） systems. The proposed algorithm is used to equalize independent ladings of all subcarriers. At the same time we compare the SDCMA blind detection with subspace-based Minimum Mean-Squared Error （MMSE） detection. The simulation results show that the pertbrmance of SDCMA blind detection is superior to that of subspace-based MMSE detection and the complexity of the former is much lower than that of the latter.

Real-Code Genetic Algorithm for Ground State Energies of Hydrogenic Donors in GaAs-（Ga,Al）As Quantum Dots

We present a global optimization method, called the real-code genetic algorithm (RGA), to the ground state energies. The proposed method does not require partial derivatives with respect to each variational parameter or solving an eigenequation, so the present method overcomes the major difficulties of the variational method. RGAs also do not require coding and encoding procedures, so the computation time and complexity are reduced. The ground state energies of hydrogenic donors in GaAs-(Ga,Al)As quantum dots have been calculated for a range of the radius of the quantum dot radii of practical interest. They are compared with those obtained by the variational method. The results obtained demonstrate the proposed method is simple, accurate, and easy implement.

Nuclear Properties of Carbon Nanotubes for Fast Neutron Detection

Fast neutron detection is a subject of great relevance in modem nuclear science and engineering, in particular, with the recent advances in nuclear fusion research, detection of fast neutron became a key issue. Nuclear properties of carbon are of special interest due to its relatively high capture cross section for fast neutrons. Devices made of silicon carbide and diamond are based on these properties, and so are being developed to be used with the proper wiring. In addition, in recent years carbon nano-tubes unveiled their electrical and mechamical properties, which can be exploited for neutron detection. In this work, we use MCNP5 Monte Carlo code to analyze the carbon nuclear properties and discuss the way nano-tubes can be used for fast neutron detection.

Measurement of the Energy Spectrum of the Neutrons inside the Neutron Flux Trap Assembled in the Center of the Reactor Core IPEN/MB-01

This paper presents the neutron energy spectrum in the central position of a neutron flux trap assembled in the core center of the research nuclear reactor IPEN/MB-01, obtained by an unfolding method. To this end, we have used several different types of activation foils （Au, Sc, Ti, Ni, and plates） which have been irradiated in the central position of the reactor core （setting number 203） at a reactor power level （64.57±2.91 watts）. The activation foils were counted by solid-state detector HPGe （high pure germanium detector） （gamma spectrometry）. The experimental data of nuclear reaction rates （saturated activity per target nucleus） and a neutron spectrum estimated by a reactor physics computer code are the main input data to get the most suitable neutron spectrum in the irradiation position obtained through SANDBP （spectrum analysis neutron detection code-version Budapest University） code： a neutron spectra unfolding code that uses an iterative adjustment method. the integral neutron flux, （2.41 ± 0.01） × 10^9 n·cm^-2·s^-1 for the thermal The adjustment resulted in （3.85 ± 0.14） × 10^9 n·cm^-2·s^-1 for neutron flux, （1.09 ±0.02） × 10^9n·cm^-2·s^-1 for intermediate neutron flux and （3.41 ± 0.02） × 10^8 n·cm^-2·s^-1 for the fast neutrons flux. These results can be used to verify and validate the nuclear reactor codes and its associated nuclear data libraries, besides, show how much effective it can be that the use of a neutron flux trap in the nuclear reactor core to increase the thermal neutron flux without increase the operation reactor power level. The thermal neutral flux increased 4.04 ± 0.21 times compared with the standard configuration of the reactor core.

Constructions of new families of nonbinary asymmetric quantum BCH codes and subsystem BCH codes

Two code constructions generating new families of good nonbinary asymmetric quantum BCH codes and good nonbinary subsystem BCH codes are presented in this paper.The first one is derived from q-ary Steane's enlargement of CSS codes applied to nonnarrow-sense BCH codes.The second one is derived from the method of defining sets of classical cyclic codes.The asymmetric quantum BCH codes and subsystem BCH codes here have better parameters than the ones available in the literature.

Inhomogeneous Quantum Codes (III):The Asymmetric Case

The stabilizer(additive)method and non-additive method for constructing asymmetric quantum codes have been established.In this paper,these methods are generalized to inhomogeneous quantum codes.

ON THE SECOND GREEDY WEIGHT FOR LINEAR CODES SATISFYING THE FULLRANK CONDITION

The maximum of g2-d2 for linear [n, k, d; q] codes C is studied. Here d2 is the smallest size of the support of 2-dimensional subcodes of C and g2 is the smallest size of the support of 2-dimensional subcodes of C which contains a codeword of weight d. The extra cost to the greedy adversary to get two symbols of information using some algorithm is g2-d2. For codes satisfying the fullrank condition of general dimensions, upper bounds on the maximum of g2-d2 are given. Under some condition we have got code C where g2-d2 reaches the upper bound.

A Family of Degenerate Codes for Depolarizing Channels

Quantum degenerate code may improve the hashing bound of quantum capacity. We propose a family of quantum degenerate codes derived from two-colorable graphs. The coherent information of the codes is analyticaJly obtained as a function of the channd noise for the depolarizing channel. We find a new code which has a higher noise threshold than that of the repetition code.

Algebraic encoding scheme for aperture 3 hexagonal discrete global grid system

Discrete Global Grid Systems(DGGSs) are spatial references that use a hierarchical tessellation of cells to partition and address the entire globe. They provide an organizational structure that permits fast integration between multiple sources of large and variable geospatial data sufficient for visualization and analysis. Despite a significant body of research supporting hexagonal DGGSs as the superior choice, the application thereof has been hindered owing in part to the lack of a rational hierarchy with an efficient addressing system. This paper presents an algebraic model of encoding scheme for the Aperture 3 Hexagonal(A3H) DGGS. Firstly, the definition of a grid cell, which is composed of vertices, edges, and a center, is introduced to describe fundamental elements of grids. Secondly, by identifying the grid cell with its center, this paper proves that cell centers at different levels can be represented exactly using a mixed positional number system in the complex plane through the recursive geometric relationship between two successive levels, which reveals that grid cells are essentially special complex radix numbers. Thirdly, it is shown that through the recursive geometric relationship of successive odd or even levels, the mixed positional number system can also be applied to uniquely represent cell centers at different levels under specific constraint conditions, according to which the encoding scheme is designed. Finally, it is shown that by extending the scheme to 20 triangular faces of the regular icosahedron,multi-resolution grids on closed surfaces of the icosahedron are addressed perfectly. Contrast experiments show that the proposed encoding scheme has the advantages of theoretical rigor and high programming efficiency and that the efficiency of cross-face adjacent cell searching is 242.9 times that of a similar scheme. Moreover, the proposed complex radix number representation is an ideal formalized description tool for grid systems. The research ideas introduced herein can be used to create a universal theoretical framework for DGGSs.

Quantum Secret Sharing with Error Correction

We investigate in this work a quantum error correction on a five-qubits graph state used for secret sharing through five noisy channels. We describe the procedure for the five, seven and nine qubits codes. It is known that the three codes always allow error recovery if only one among the sent qubits is disturbed in the transmitting channel. However, if two qubits and more are disturbed, then the correction will depend on the used code. We compare in this paper the three codes by computing the average fidelity between the sent secret and that measured by the receivers. We will treat the case where, at most, two qubits are affected in each one of five depolarizing channels.

Quantum proxy signature scheme with public verifiability

In recent years, with the development of quantum cryptography, quantum signature has also made great achievement. However,the effectiveness of all the quantum signature schemes reported in the literature can only be verified by a designated person.Therefore, its wide applications are limited. For solving this problem, a new quantum proxy signature scheme using EPR quantumentanglement state and unitary transformation to generate proxy signature is presented. Proxy signer announces his public key whenhe generates the final signature. According to the property of unitary transformation and quantum one-way function, everyone canverify whether the signature is effective or not by the public key. So the quantum proxy signature scheme in our paper can be publicverified. The quantum key distribution and one-time pad encryption algorithm guarantee the unconditional security of this scheme.Analysis results show that this new scheme satisfies strong non-counterfeit and strong non-disavowal.