Variance-based uncertainty relations for incompatible observables

Quantum Information Processing - We formulate uncertainty relations for arbitrary finite number of incompatible observables. Based on the sum of variances of the observables, both Heisenberg-type...     

Basic observables for a calculus for global computing

We develop the semantic theory of a foundational language for modelling applications over global computers whose interconnection structure can be explicitly manipulated. Together with process distribution, process mobility and remote asynchronous communication through distributed data repositories, the language has primitives for explicitly modelling inter-node connections and for dynamically activating and deactivating them. For the proposed language, we define natural notions of extensional observations and study their closure under operational reductions and/or language contexts to obtain barbed congruence and may testing equivalence. We then focus on barbed congruence and provide an alternative characterisation in terms of a labelled bisimulation. To test practical usability of the semantic theory, we model a system of communicating mobile devices and use the introduced proof techniques to verify one of its key properties.     

基于蒙特卡洛方法的碰撞预警系统仿真

本文提出了一种基于蒙特卡洛方法的汽车碰撞预警系统.本系统可以自动连续测量行驶车辆前方障碍物的速度和方位等数据,经过估计产生车体和目标的姿态,利用蒙特卡洛方法计算碰撞概率,发出适当的警报给驾驶员.仿真结果表明此算法能够比较精确地估计车辆的安全级别,产生相对准确的警报,为开展快速的碰撞预警系统的研究提供了一种可行方案.     

micrOMEGAs_3: A program for calculating dark matter observables

micrOMEGAs  is a code to compute dark matter observables in generic extensions of the standard model. This new version of micrOMEGAs  is a major update which includes a generalization of the Boltzmann equations to accommodate models with asymmetric dark matter or with semi-annihilation and a first approach to a generalization of the thermodynamics of the Universe in the relic density computation. Furthermore a switch to include virtual vector bosons in the final states in the annihilation cross sections or relic density computations is added. Effective operators to describe loop-induced couplings of Higgses to two-photons or two-gluons are introduced and reduced couplings of the Higgs are provided allowing for a direct comparison with recent LHC results. A module that computes the signature of DM captured in celestial bodies in neutrino telescopes is also provided. Moreover the direct detection module has been improved as concerns the implementation of the strange “content” of the nucleon. New extensions of the standard model are included in the distribution.     

Compatibility of observables on effect algebras

We compare different notions of simultaneous measurability (compatibility) of observables on lattice \(\sigma \)-effect algebras and more generally, on \(\sigma \)-effect algebras that can be covered by \(\sigma \)-MV-algebras. We prove that every \(\sigma \)-MV-algebra is the range of a \(\sigma \)-additive observable, and we compare the following notions of compatibility of observables: joint measurability, coexistence, joint measurability of binarizations, coexistence of binarizations, smearings of the same observable. We prove that if there is a faithful state on the effect algebra, then any two standard observables that are smearings of the same (sharp) observable admit a generalized joint observable.     

A note on observables on MV-algebras

 A criterion when a subset of an MV-algebra is contained in the range of a (finitely additive) observable is given. It is used to prove that every at most countable subset of any MV-algebra is contained in the range of an observable. A much stronger result holds for any bold fuzzy algebra [0,1] ^S , which is whole contained in the range of a (σ-additive) observable.     

Period distribution for error-correcting codes

The period distribution of an error-correcting code tells how many codewords in the code have a specific minimum period, where the minimum period of a codeword is the minimum number of cyclic shifts necessary to obtain the same codeword. The period distributions of R-S codes, extended R-S codes, and cyclic codes, in general, will be calculated in this paper. The period di stribution problem for the other noncyclic codes still remains unknown.     

用于CPM的LT码设计

研究了在加性高斯白噪声(AWGN)信道中采用连续相位调制(CPM)的LT码串行级联系统.给出了一种联合解调译码算法,并运用高斯近似方法优化设计了在CPM下LT码的度分布函数.计算机仿真结果表明,优化设计的LT-CPM系统具有更低的误码率.     

Algebraic codes for network coding

The subspace metric is an object of active research in network coding. Nevertheless, little is known on codes over this metric. In the present paper, several classes of codes over subspace metric are defined and investigated, including codes with distance 2, codes with the maximal distance, and constant-distance constant-dimension codes. Also, Gilbert-type bounds are presented.     

Indices for testing neural codes

One of the most critical challenges in systems neuroscience is determining the neural code. A principled framework for addressing this can be found in information theory. With this approach, one can determine whether a proposed code can account for the stimulus-response relationship. Specifically, one can compare the transmitted information between the stimulus and the hypothesized neural code with the transmitted information between the stimulus and the behavioral response. If the former is smaller than the latter (i.e., if the code cannot account for the behavior), the code can be ruled out. The information-theoretic index most widely used in this context is Shannon's mutual information. The Shannon test, however, is not ideal for this purpose: while the codes it will rule out are truly nonviable, there will be some nonviable codes that it will fail to rule out. Here we describe a wide range of alternative indices that can be used for ruling codes out. The range includes a continuum from Shannon information to measures of the performance of a Bayesian decoder. We analyze the relationship of these indices to each other and their complementary strengths and weaknesses for addressing this problem.     

Gray codes for reflectable languages

We classify a type of language called a reflectable language. We then develop a generic algorithm that can be used to list all strings of length n for any reflectable language in Gray code order. The algorithm generalizes Gray code algorithms developed independently for k-ary strings, restricted growth strings, and k-ary trees, as each of these objects can be represented by a reflectable language. Finally, we apply the algorithm to open meandric systems which can also be represented by a reflectable language.     

An algorithm for Gray codes

The algorithm generates a list of distinct binaryn-tuples such that eachn-tuple differs from the one preceding it in just one coordinate [1]. The binary Gray code is often used to generate all subsets of a given set [2]. The whole theory can easily be generalized to generatingr-ary codes,r>2, [3].     

MACS系统在水煤浆导热油锅炉控制系统的应用

本文在分析水煤浆导热油锅炉工艺特点和控制需求的基础上,阐述丁基于MACS控制系统实现了锅炉本体、导热油、燃料三大系统的过程生产控制,实现水煤浆导热油锅炉整体平稳生产运行;并在此基础上实现了锅炉备控制参数的联锁保护,从而保证了锅炉的安全生产。     

Hierarchical codes: A flexible trade-off for erasure codes in peer-to-peer storage systems

Redundancy is the basic technique to provide reliability in storage systems consisting of multiple components. A redundancy scheme defines how the redundant data are produced and maintained. The simplest redundancy scheme is replication, which however suffers from storage inefficiency. Another approach is erasure coding, which provides the same level of reliability as replication using a significantly smaller amount of storage. When redundant data are lost, they need to be replaced. While replacing replicated data consists in a simple copy, it becomes a complex operation with erasure codes: new data are produced performing a coding over some other available data. The amount of data to be read and coded is d times larger than the amount of data produced, where d, called repair degree, is larger than 1 and depends on the structure of the code. This implies that coding has a larger computational and I/O cost, which, for distributed storage systems, translates into increased network traffic. Participants of Peer-to-Peer systems often have ample storage and CPU power, but their network bandwidth may be limited. For these reasons existing coding techniques are not suitable for P2P storage. This work explores the design space between replication and the existing erasure codes. We propose and evaluate a new class of erasure codes, called Hierarchical Codes, which allows to reduce the network traffic due to maintenance without losing the benefits given by traditional erasure codes.     

DNA codes for nonadditive stem similarity

DNA sequences are sequences with elements from the quaternary DNA alphabet {A, C, G, T}. An important property of them is their directedness and ability to form duplexes as a result of hybridization process, i.e., coalescing two oppositely directed sequences. In biological experiments exploiting this property it is necessary to generate an ensemble of such sequences (DNA codes) consisting of pairs of DNA sequences referred to as Watson-Crick duplexes. Furthermore, for any two words of the DNA code that do not form a Watson-Crick duplex, hybridization energy—stability measure of a potential DNA duplex—is upper bounded by a constant specified by conditions of an experiment. This problem can naturally be interpreted in terms of coding theory. Continuing our previous works, we consider a nonadditive similarity function for two DNA sequences, which most adequately models their hybridization energy. For the maximum cardinality of DNA codes based on this similarity, we establish a Singleton upper bound and present an example of an optimal construction. Using ensembles of DNA codes with special constraints on codewords, which we call Fibonacci ensembles, we obtain a random-coding lower bound on the maximum cardinality of DNA codes under this similarity function.     

Layered interval codes for TCAM-based classification

Ternary content-addressable memories (TCAMs) are increasingly used for high-speed packet classification. TCAMs compare packet headers against all rules in a classification database in parallel and thus provide high throughput.TCAMs are not well-suited, however, for representing rules that contain range fields and previously published algorithms typically represent each such rule by multiple TCAM entries. The resulting range expansion can dramatically reduce TCAM utilization because it introduces a large number of redundant TCAM entries. This redundancy can be mitigated by making use of extra bits, available in each TCAM entry.We present a scheme for constructing efficient representations of range rules, based on the simple observation that sets of disjoint ranges may be encoded much more efficiently than sets of overlapping ranges. Since the ranges in real-world classification databases are, in general, non-disjoint, the algorithms we present split ranges between multiple layers, each of which consists of mutually disjoint ranges. Each layer is then coded and assigned its own set of extra bits.Our layering algorithms are based on approximations for specific variants of interval-graph coloring. We evaluate these algorithms by performing extensive comparative analysis on real-life classification databases. Our analysis establishes that our algorithms reduce the number of redundant TCAM entries caused by range rules by more than 60% as compared with best range-encoding prior work.     

Error exponents for product convolutional codes

An upper bound on the error probability (first error event) of product convolutional codes over a memoryless binary symmetric channel, and the resulting error exponent are derived. The error exponent is estimated for two decoding procedures. It is shown that, for both decoding methods, the error probability exponentially decreasing with the constraint length of product convolutional codes can be attained with nonexponentially increasing decoding complexity. Both estimated error exponents are similar to those for woven convolutional codes with outer and inner warp.