日常交通出行时间管理悖论

第一部分介绍扎哈维假设,随后指出城市交通出行时间预算管理假设的悖论;鉴于在低密度城市中,交通出行速度的加快导致机动性提高,第二部分将就城市密度对城市交通的影响(特别是对中等密度城市的交通影响)进行分析.最后,对中国的城市发展提一些想法.     

Mitter conjecture for low dimensional estimation algebras in non-linear filtering†

It is well known that a systematical way to construct finite dimensional filter is to classify all finite dimensional estimation algebras. Mitter conjecture, which states that all functions in any finite dimensional estimation algebra are necessarily degree one polynomial, plays a crucial role in classifying all finite dimensional estimation algebras. The purpose of this paper is to prove the Mitter Conjecture for estimation algebra of dimension at most 5 with arbitrary state space dimension.     

Some Aspects of Synchronization of DFA

A word w is called synchronizing （recurrent, reset, directable） word of deterministic finite automata （DFA） if w brings all states of the automaton to a unique state. According to the famous conjecture of Cerny from 1964, every n-state synchronizing automaton possesses a synchronizing word of length at most （n - 1）2. The problem is still open. It will be proved that the Cerny conjecture holds good for synchronizing DFA with transition monoid having no involutions and for every n-state （n 〉 2） synchronizing DFA with transition monoid having only trivial subgroups the minimal length of synchronizing word is not greater than （n - 1）2/2. The last important class of DFA involved and studied by Schutzenberger is called aperiodic; its automata accept precisely star-free languages. Some properties of an arbitrary synchronizing DFA were established.     

The “log rank” conjecture for modular communication complexity

The “log rank” conjecture involves the question of how precisely the deterministic communication complexity of a problem can be described in terms of algebraic invariants of the communication matrix of this problem. We answer this question in the context of modular communication complexity. We show that the modular communication complexity can be exactly characterised in terms of the logarithm of a certain rigidity function of the communication matrix. Thus, we are able to exactly determine the modular communication complexity of several problems, such as, e.g., set disjointness, comparability, and undirected graph connectivity. From the bounds obtained for the modular communication complexity we deduce exponential lower bounds on the size of depth-two circuits having arbitrary symmetric gates at the bottom level and a MOD _m -gate at the top. Received: April 14, 2000.     

视频帧差图像编码研究

视频压缩效率的提高在很大程度上取决于如何减少用于传输运动补偿预测误差的信息量,即如何有效地编码视频帧差图像。首先对帧差图像的统计特性进行了分析,然后以基于DCT、基于小波和基于HVS等帧差图像编码为线索,对视频帧差图像编码的进展情况进行了分析和讨论,最后对视频帧差图像编码的进一步发展进行了展望。     

Sigmund Freud and Minna Bernays: Primal curiosity, primal scenes, primal fantasies--And prevarication.

Attacks on Freud's theories on sexuality began when Freud launched his studies on hysteria in the last decade of the 19th century and are still ongoing. The latest cavil is embedded in a sensation exploded in the summer of 2006 by Franz Maciejewski of Heidelberg, Germany. It was publicized in front-page reportage by New York Times columnist Ralph Blumenthal (2006): "A Century-Old Swiss Hotel Log Hints at an Illicit Desire That Dr. Freud Didn't Repress," additionally editorialized as adequate "to impugn [Freud's] reputation" (p. A4). In this article, arguments ad hominem, bordering on Freud-bashing, concerning Freud as a person and his relationship with his sister-in-law Minna Bernays, are separated from arguments ad rem, regarding the merits of Freud's theory of the Oedipus complex. The evidence presented by Maciejewski is found to be flawed and to not rise above the level of conjecture. Similarly, his construction that the alleged sexual affair between Freud and his sister-in-law was tantamount to incest, and thus source of theory of the Oedipus complex, has no standing either. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

概率为0或1的事件的一个定理

针对部分学者对作者《概率论中的确定误差限》一文中定理 7的证明较弱的意见 ,补充证明了在有限多次Bernoulli试验中 ,概率为零的事件一定不出现 ,概率为 1的事件一定在每次试验中出现 从而使Goldbach猜想等问题中的误差限获得了完全肯定的结论     

Shortest synchronizing strings for Huffman codes

Most complete binary prefix codes have a synchronizing string, that is a string that resynchronizes the decoder regardless of its previous state. This work presents an upper bound on the length of the shortest synchronizing string for such codes. Two classes of codes with a long shortest synchronizing string are presented. It is known that finding a synchronizing string for a code is equivalent to finding a synchronizing string of some finite automaton. The Černý conjecture for this class of automata is discussed.