On-Line Paging against Adversarially Biased Random Inputs

In evaluating an algorithm, worst-case analysis can be overly pessimistic. Average-case analysis can be overly optimistic. An intermediate approach is to show that an algorithm does well on a broad class of input distributions. Koutsoupias and Papadimitriou recently analyzed the least-recently-used (LRU) paging strategy in this manner, analyzing its performance on an input sequence generated by a so-called diffuse adversary -- one that must choose each request probabilitistically so that no page is chosen with probability more than some fixed epsilon>0. They showed that LRU achieves the optimal competitive ratio (for deterministic on-line algorithms), but they didn't determine the actual ratio. In this paper we estimate the optimal ratios within roughly a factor of two for both deterministic strategies (e.g. least-recently-used and first-in-first-out) and randomized strategies. Around the threshold epsilon ~ 1/k (where k is the cache size), the optimal ratios are both Theta(ln k). Below the threshold the ratios tend rapidly to O(1). Above the threshold the ratio is unchanged for randomized strategies but tends rapidly to Theta(k) for deterministic ones. We also give an alternate proof of the optimality of LRU.Comment: Conference version appeared in SODA '98 as "Bounding the Diffuse Adversary

Asymptotic expansions for the escape rate of stochastically perturbed unimodal maps

The escape rate of a stochastic dynamical system can be found as an expansion in powers of the noise strength. In previous work the coefficients of such an expansion for a one-dimensional map were fitted to a general form containing a few parameters. These parameters were found to be related to the fractal structure of the repeller of the system. The parameter alpha, the "noise dimension", remains to be interpreted. This report presents new data for alpha showing that the relation to the dimensions is more complicated than predicted in earlier work and oscillates as a function of the map parameter, in contrast to other dimension-like quantities.Comment: 7 pages, 5 figure

Górnicy węgla kamiennego : uprzywilejowana grupa społeczna w Polsce w okresie komunizmu

Węgiel był podstawowym polskim surowcem energetycznym i eksportowym, dostarczał więc krajowi niezbędnych dewiz. Przez cały okres rządów komunistycznych w Polsce górników pracujących w kopalniach węgla kamiennego nadmiernie eksploatowano, ale jednocześnie przyznawano im liczne przywileje socjalne. Zawód górnika uznano za najważniejszy i najcenniejszy dla kraju, a samych górników traktowano jak bohaterów narodowych. W miarę upływu czasu ich przywileje socjalne były coraz szersze. W listopadzie 1949 r. rząd przyjął dokument zwany "Kartą Górnika" nadający szczególne przywileje górnikom w górnictwie węglowym. W tym samym roku wprowadzono odznaczenie "Zasłużony Górnik Polski Ludowej". Ze względu jednak na ciężkie warunki wciąż brakowało rąk do pracy w kopalniach. Dla zapewnienia jak największego wydobycia węgla w 1978 r. wprowadzono czterobrygadowy system pracy pod ziemią. Dzięki temu o każdej porze dnia i nocy wszystkie stanowiska pracy były obsadzone. Jedną z form zachęty do pracy w kopalniach była obietnica szybkiego otrzymania własnego mieszkania. Przy wielu kopalniach funkcjonowały stołówki, osobne sklepy oraz punkty usługowe. Kopalnie organizowały dostawy produktów spożywczych po niższych cenach. Od początku lat 80. XX w. rozpoczął się w Polsce głęboki kryzys społeczny i gospodarczy. Chcąc zachęcić górników do jeszcze większego wysiłku, wprowadzono "dobrowolną" pracę w wolne soboty, która była podwójnie wynagradzana, a tak zarobiona kwota była zwolniona z podatku. Górnicy byli najbardziej hołubioną grupą zawodową w Polsce Ludowej, ale też najbardziej wykorzystywaną ekonomicznie. Ich życie było niezwykle trudne, chociaż ich pensje były znacznie wyższe niż pracowników w innych gałęziach przemysłu.Coal was the basic Polish energy resource, and at the same time its export provided the country with the necessary injections of foreign currency. During the entire period of Communist rule in Poland, miners working in hard coal mines were, on the one hand, over-exploited, while, on the other, they were granted numerous social benefits. The profession of miner was considered the most important and valuable for the country, and the miners themselves were treated as national heroes. Over time, miners' social privileges were increasingly extended. In November 1949, the government adopted a document called the "Miner's Charter", concerning special privileges for miners in the coal mining industry. In the same year the "Distinguished Miner of Socialist Poland" decoration was introduced. However, due to the harsh conditions, there was still a shortage of manpower in the mines. To ensure maximum coal extraction, a four-brigade working system was introduced underground in 1978. As a result, the workplace was manned at all times of the day and night. One form of incentive to work in the mines was the promise of a accelerated access to housing. Many mines had canteens, separate shops, and service outlets. The mines organized the delivery of food products at lower prices. From the beginning of the 1980s, Poland entered a decade-long deep social and economic crisis. To encourage miners to make even greater efforts, "voluntary" work on free Saturdays was introduced, which was doubled in pay and the amount thus earned was tax-free. The miners were the most highly valued occupational group in Socialist Poland, but it is the most economically exploited group. Their life was extremely difficult, although miners' salaries were much higher than in other branches of industry

The real and expected privileges of the Security Service collaborators recruited from academic milieu in the 1980s

Despite the elaborated techniques of electronic surveillance, personal sources of information still remain the best possible method of infiltrating a criminal milieu. Such methods gain special importance in totalitarian states. Collaborating with the Security Service almost always had some notable benefits. For some of the TWs, collaborating was an additional, sometimes quite substantial, source of income. One of repeating motives for collaboration was a will to improve one’s professional position or to easily obtain a permission to go abroad. There were also persons, who were impressed with having contacts with the Security Service functionaries. Almost all collaborators were using different forms of help from the part of the Security Service. Most of them would obtain real financial and material profits. The spectrum of favours offered to those helping the repressive state apparatus was very extensive

Translation-Mediated Stress Responses: Mining of Ribosome Profiling Data

Advances in next-generation sequencing platforms during the past decade have resulted in exponential increases in biological data generation. Besides applications in determining the sequences of genomes and other DNA elements, these platforms have allowed the characterization of cell-wide mRNA pools under different conditions and in different tissues. In 2009, Ingolia and colleagues developed an extension of high-throughput sequencing that provides a snapshot of all cellular mRNA fragments protected by translating ribosomes, dubbed ribosome profiling. This approach allows detection of differential translation activity, annotation of novel protein coding sequences and variants, identification of ribosome pause sites and estimates of de novo protein synthesis. As with other sequencing based methodologies, a major challenge of ribosome profiling has been sorting, filtering and interpreting the gigabytes of data produced during the course of a typical experiment. In this thesis, I developed and applied computational pipelines to interrogate ribosome profiling data in relation to gene expression in several viruses and eukaryotic species, as well as to identify sites of ribosomal pausing and sites of non-canonical translation activity. Specifically, I applied various control analyses for characterizing the quality of profiling data and developed scripts for visualizing genome-based (exon-by-exon) rather than transcript-based ribosome footprint alignments. I also examined the challenge of mapping footprints to repetitive sequences in the genome and propose ways to mitigate the associated problems. I performed differential expression analyses on data from coronavirus-infected murine cells, retrovirus-infected human cells and temperature-stressed Arabidopsis thaliana plants. Dissection of translational responses in Arabidopsis thaliana during heat shock or cold shock revealed several groups of genes that were highly upregulated within 10 minutes of temperature challenge. Analysis of the branches of the unfolded protein and integrated stress responses during coronavirus infection allowed for deconvolution of transcriptional and translational contributions. During the course of these analyses, I identified errors in a recently publicized algorithm for detection of differential translation, and wrote corrections that have now been pulled into the repository for this package. Comparison of the translational kinetics of the dengue virus infection in mosquito and human cell lines revealed host-specific sites of ribosome pausing and RNA accumulation. Analysis of HIV profiling data revealed footprint peaks which were in agreement with previously proposed models of peptide or RNA mediated ribosome stalling. I also developed a simulation to identify transcripts that are prone to generating RPFs with multiple alignments during the read mapping process. Together, the scripts and pipelines developed during the course of this work will serve to expedite future analyses of ribosome profiling data, and the results will inform future studies of several important pathogens and temperature stress in plants.Gates-Cambridge Scholarshi

“Protection” of Silesian hard coal mines by the state Security Service in the 1980s (on the example of hard coal mine “Katowice”)

During the entire period of the Polish People’s Republic the Polish state security forces conducted surveillance operations of factories and other workplaces. All spheres of activity – political, social and economic – were controlled. These actions intensified in the 1980s, a unique period in the recent history of Poland, after the workers’ strikes in August 1980 and the creation of the Independent Self-Governing Trade Union (NSZZ) “Solidarność”. In response to the upheaval, the martial law was introduced, casting a grim shadow on the social and economic reality of the entire decade. Because of the importance of coal mining for the country’s economic system, the activities of state security forces were meticulously carried out in the mines, including the hard coal mine “Katowice”. All actions were controlled and recorded, not only those of workers who sympathized with powers hostile to the regime, but any event disturbing the rhythm of work – entirely coincidental events were tracked alongside possible cases of sabotage. Regardless of the real intentions behind these activities, this scrutiny of the state apparatus created a kind of chronicle of events that took place in the hard coal mine “Katowice” in the period under discussion