Noiseless compression using non-Markov models

Adaptive data compression techniques can be viewed as consisting of a model specified by a database common to the encoder and decoder, an encoding rule and a rule for updating the model to ensure that the encoder and decoder always agree on the interpretation of the next transmission. The techniques which fit this framework range from run-length coding, to adaptive Huffman and arithmetic coding, to the string-matching techniques of Lempel and Ziv. The compression obtained by arithmetic coding is dependent on the generality of the source model. For many sources, an independent-letter model is clearly insufficient. Unfortunately, a straightforward implementation of a Markov model requires an amount of space exponential in the number of letters remembered. The Directed Acyclic Word Graph (DAWG) can be constructed in time and space proportional to the text encoded, and can be used to estimate the probabilities required for arithmetic coding based on an amount of memory which varies naturally depending on the encoded text. The tail of that portion of the text which was encoded is the longest suffix that has occurred previously. The frequencies of letters following these previous occurrences can be used to estimate the probability distribution of the next letter. Experimental results indicate that compression is often far better than that obtained using independent-letter models, and sometimes also significantly better than other non-independent techniques

Parrondo games as lattice gas automata

Parrondo games are coin flipping games with the surprising property that alternating plays of two losing games can produce a winning game. We show that this phenomenon can be modelled by probabilistic lattice gas automata. Furthermore, motivated by the recent introduction of quantum coin flipping games, we show that quantum lattice gas automata provide an interesting definition for quantum Parrondo games.Comment: 12 pages, plain TeX, 10 PostScript figures included with epsf.tex (ignore the under/overfull \vbox error messages); for related work see http://math.ucsd.edu/~dmeyer/research.htm

The Rényi Redundancy of Generalized Huffman Codes

Huffman's algorithm gives optimal codes, as measured by average codeword length, and the redundancy can be measured as the difference between the average codeword length and Shannon's entropy. If the objective function is replaced by an exponentially weighted average, then a simple modification of Huffman's algorithm gives optimal codes. The redundancy can now be measured as the difference between this new average and A. Renyi's (1961) generalization of Shannon's entropy. By decreasing some of the codeword lengths in a Shannon code, the upper bound on the redundancy given in the standard proof of the noiseless source coding theorem is improved. The lower bound is improved by randomizing between codeword lengths, allowing linear programming techniques to be used on an integer programming problem. These bounds are shown to be asymptotically equal. The results are generalized to the Renyi case and are related to R.G. Gallager's (1978) bound on the redundancy of Huffman codes

An analysis of short haul air passenger demand, volume 2

Several demand models for short haul air travel are proposed and calibrated on pooled data. The models are designed to predict demand and analyze some of the motivating phenomena behind demand generation. In particular, an attempt is made to include the effects of competing modes and of alternate destinations. The results support three conclusions: (1) the auto mode is the air mode's major competitor; (2) trip time is an overriding factor in intermodal competition, with air fare at its present level appearing unimportant to the typical short haul air traveler; and (3) distance appears to underly several demand generating phenomena, and therefore, must be considered very carefully to any intercity demand model. It may be the cause of the wide range of fare elasticities reported by researchers over the past 15 years. A behavioral demand model is proposed and calibrated. It combines the travel generating effects of income and population, the effects of modal split, the sensitivity of travel to price and time, and the effect of alternative destinations satisfying the trip purpose

Orbiter windward surface entry Heating: Post-orbital flight test program update

Correlations of orbiter windward surface entry heating data from the first five flights are presented with emphasis on boundary layer transition and the effects of catalytic recombination. Results show that a single roughness boundary layer transition correlation developed for spherical element trips works well for the orbiter tile system. Also, an engineering approach for predicting heating in nonequilibrium flow conditions shows good agreement with the flight test data in the time period of significant heating. The results of these correlations, when used to predict orbiter heating for a high cross mission, indicate that the thermal protection system on the windward surface will perform successfully in such a mission

Tort liability for infringements on the right of reputation under Chinese law : a review of selected court cases

This paper was first published in Jusletter of June 27, 2016 (http://jusletter.weblaw.ch/juslissues/2016/852/tort-liability-for-i_8f87f5e1cb.html__ONCE) and was slightly modified for the publication in the Fajus Research Paper Series on Chinese and East Asian Law.Having and giving "face" has always been important in Chinese society. It is not surprising, therefore, that the right of reputation has found its place in the legislation of the PRC when laws were re-introduced in the 1980ies. While the legal provisions seem pretty straightforward, court cases show that the Chinese legal system and Chinese society are very much different from their counterparts in the West."Das Gesicht wahren" ist in der chinesischen Gesellschaft sehr bedeutend. Es ist denn auch nicht weiter verwunderlich, dass dem Ehrenschutz ein Platz in der Gesetzgebung eingeräumt wurde, als diese ab 1980 in der Volksrepublik China wieder eingeführt wurde. Auch wenn die Gesetzesbestimmungen auf den ersten Blick recht klar erscheinen, zeigt eine Analyse der Rechtsprechung, dass das chinesische Rechtssystem und die chinesische Gesellschaft doch ganz anders sind als in der westlichen Hemisphäre

Simulation of spontaneous G protein activation reveals a new intermediate driving GDP unbinding

Activation of heterotrimeric G proteins is a key step in many signaling cascades. However, a complete mechanism for this process, which requires allosteric communication between binding sites that are ~30 Å apart, remains elusive. We construct an atomically detailed model of G protein activation by combining three powerful computational methods: metadynamics, Markov state models (MSMs), and CARDS analysis of correlated motions. We uncover a mechanism that is consistent with a wide variety of structural and biochemical data. Surprisingly, the rate-limiting step for GDP release correlates with tilting rather than translation of the GPCR-binding helix 5. β-Strands 1 - 3 and helix 1 emerge as hubs in the allosteric network that links conformational changes in the GPCR-binding site to disordering of the distal nucleotide-binding site and consequent GDP release. Our approach and insights provide foundations for understanding disease-implicated G protein mutants, illuminating slow events in allosteric networks, and examining unbinding processes with slow off-rates

A Sensual Exploration of Melancholy

What does it mean to be melancholy? It is a distinct and personal emotion—a type of sadness and a feeling all its own. Melancholy is not something people usually seek out, but it can be a comfortable, pensive, and creative space to sit in. The beautiful thing about melancholy is how one is able to be both joyful and sorrowful at the same time. I began the project by conducting a survey about what others think sadness smells, tastes, and sounds like. I have also researched poetry and music. I explore melancholy in different mediums and creative techniques, including a melancholy package design, spatial design, a song, prints, interface design, and tattoos. Why do so many people avoid sadness and melancholy when they are sensual, visceral, and natural aspects of life? I want to express how and why I am able to find peace in this form of deep sadness. My thesis will show others that experiencing and thinking about melancholy instead of avoiding it can yield some beautiful results. My thesis is a deep dive into my own subconscious. It is an attempt to understand my own affinity for the emotion just as much as it is a creative project