A Fast Algorithm for Adaptive Prefix Coding

In this paper we present a new algorithm for adaptive prefix coding. Our algorithm encodes a text S of m symbols in O(m) time, i.e., in O(1) amortized time per symbol. The length of the encoded string is bounded above by (H+1)m+O(nlog ² m) bits where n is the alphabet size and H is the entropy. This is the first algorithm that adaptively encodes a text in O(m) time and achieves an almost optimal bound on the encoding length in the worst case. Besides that, our algorithm does not depend on an explicit code tree traversal. A preliminary version of this paper appeared in the Proceedings of the 2006 IEEE International Symposium on Information Theory (ISIT 2006). M. Karpinski’s work partially supported by a DFG grant, Max-Planck Research Prize, and IST grant 14036 (RAND-APX). Y. Nekrich’s work partially supported by IST grant 14036 (RAND-APX).     

An oscillatory neural model of multiple object tracking

An oscillatory neural network model of multiple object tracking is described. The model works with a set of identical visual objects moving around the screen. At the initial stage, the model selects into the focus of attention a subset of objects initially marked as targets. Other objects are used as distractors. The model aims to preserve the initial separation between targets and distractors while objects are moving. This is achieved by a proper interplay of synchronizing and desynchronizing interactions in a multilayer network, where each layer is responsible for tracking a single target. The results of the model simulation are presented and compared with experimental data. In agreement with experimental evidence, simulations with a larger number of targets have shown higher error rates. Also, the functioning of the model in the case of temporarily overlapping objects is presented.     

Note: Rotational compliance and instantaneous center of rotation in segmented and V-shaped notch hinges

This note shows a technique for the calculation of rotational compliance (stiffness) and develops a generalized mathematical model for the virtual center of rotation position in concave, segmented, and V-shaped notch hinges using Chebyshev's polynomials. The calculational results are in a good agreement with experimental data and finite element model verified output with estimated differences of less than 10%. This agreement shows that our tractable model is a general one for rotational compliance and the evaluation of a virtual center of rotation position in any type of concave flexure notch hinges.     

Temporal Reasoning for a Collaborative Planning Agent in a Dynamic Environment

We present a temporal reasoning mechanism for an individual agent situated in a dynamic environment such as the web and collaborating with other agents while interleaving planning and acting. Building a collaborative agent that can flexibly achieve its goals in changing environments requires a blending of real-time computing and AI technologies. Therefore, our mechanism consists of an Artificial Intelligence (AI) planning subsystem and a Real-Time (RT) scheduling subsystem. The AI planning subsystem is based on a model for collaborative planning. The AI planning subsystem generates a partial order plan dynamically. During the planning it sends the RT scheduling subsystem basic actions and time constraints. The RT scheduling subsystem receives the dynamic basic actions set with associated temporal constraints and inserts these actions into the agent's schedule of activities in such a way that the resulting schedule is feasible and satisfies the temporal constraints. Our mechanism allows the agent to construct its individual schedule independently. The mechanism handles various types of temporal constraints arising from individual activities and its collaborators. In contrast to other works on scheduling in planning systems which are either not appropriate for uncertain and dynamic environments or cannot be expanded for use in multi-agent systems, our mechanism enables the individual agent to determine the time of its activities in uncertain situations and to easily integrate its activities with the activities of other agents. We have proved that under certain conditions temporal reasoning mechanism of the AI planning subsystem is sound and complete. We show the results of several experiments on the system. The results demonstrate that interleave planning and acting in our environment is crucial.     

Cooper-like Pairing and Energy Gap Induced by Ion Electronic Polarizability

We explore the possibility that the ionic electron polarizabilities of the oxygen ions in the cuprates and bismutates and the polarizabilities of As and Se ions in the iron pnictides contribute to charge carrier pairing leading to high Tc superconductivity. Using the fact that the ionic polarization responds to an abrupt change in the electric field is practically instantaneous, we find that charge carriers attract each other in limited regions in the two carrier position space. The attractive potential is used to calculate quantum mechanically the Cooper-like pairing energy and wave function and the gap energy showing they are consistent with pairing and gap energies of high Tc superconductors. Qualitative considerations show that this model may explain the large pairing energy observed in high Tc superconductors, the very short inter-carrier distance, the fact that Tc vanishes at very low and very high doping levels, and the dramatic increase in Tc of a one-unit cell thick FeSe film grown on SrTiO₃ substrate.     

增加采样保持器的记忆电压的取值范围

采样保持器应用于模数转换器之前。基本的采样保持电路由两个放大运算器（A1和A2）.     

Scheduling UET-UCT tasks: branch-and-bound search in the priority space

The paper is concerned with the problem of scheduling partially ordered unit execution time tasks on parallel processors with unit communication delays and release times. Two criteria are considered, the maximum lateness and its particular case, the makespan. This problem plays an important role in scheduling theory and was originally inspired by the applications to multi-processor computer systems. It is well known that for both criteria the problem is NP-hard in the strong sense. The paper presents an implementation of the branch-and-bound method which does not partition the feasible region explicitly. The theoretical results are complemented by computational experiments.     

开创下一代互联网应用标准——用Adobe Flex创建功能丰富的Internet应用程序

用于开发功能丰富的Internet应用程序的工具 有一种新型的生产质量的应用程序，它们提供的Ul至少与客户机-服务器应用程序一样出色，也不需要在用户的计算机上进行任何部署。这些应用程序称为富因特网应用程序（Rich Intemet Application，RIA）。