122,911 research outputs found
Investigating topics and style in Vuta N`Kuvute by Shafi Adam Shafi
No full textIn the last decades many literary critics have appraised the works of Zanzibarian writers; referring to the prose of Mohamed Suleiman Mohamed, Said Ahmed Mohamed and Shafi Adam Shafi, M M. Mulokozi wrote in 1985: \"The most significant, and certainly most spectacular, development in the Swahili fiction of the Seventies and Eighties has been the emergence of Zanzibar as the producer of the best Swahili fiction to date, and the apparent torch bearer for the Kiswahili novel of the near future\" (Arnold 1985: 174). The same enthusiasm was shared by R. Ohly who, confronting the novels written by Zanzibarian writers and those by Tanzanian and Kenyan writers in a time span going from 1975 to 1981, has defined the Zanzibarian prose a challenge to the artistic competence of other Swahili writers (cf. Ohly 1990).
Although I found the comparative pattern used by Ohly debatable, having concentrated for the up-country literary production only on popular short novels - to be better evaluated not following negative, contrastive cliches but within the context of that particular trend -, obscuring moreover other talented writers like Euphrase Kezilahabi or Claude Mung`ong`o, his criticism has nevertheless the merit of having highlighted the main qualities of Zanzibarian novels, namely a deep interest for historical and social matters, along with an extremely rich and colourful language and a serious concern for stylistic features. These attributes of Zanzibarian literary style fit very well to the last novel by Shafi Adam Shafi, Vuta n`kuvute, published in 1999; in the following pages my aim is to explore the way the author of this work artistically manipulates themes, literary suggestions and stylistic devices, re-elaborating thus the experience of Kiswahili and Zanzibarian prose in a creative way
The relationship between ilm and khabar in the work of al-Shafii
No full textThis study examines in detail the basis of al-Shafi`i's arguments for the
supremacy of oral tradition over communal legal practice. It concentrates on one
broad issue, the definition of `ilm (knowledge) and one technical issue, the problem
of authenticating a particular khabar (oral tradition or report, plural akhbar, ) and its
binding nature, especially a report of the category known as the specialists' report
(khabar al-khassa). On the first issue, this study examines the concept of knowledge
based on reports (`ilm al-khabar) because it had an important influence on al-Shafi`i.
This is followed by a detailed account of al-Shafi`i's own discussion of `ilm. It brings
out clearly that al-Shafi`i means religious law when discussing `ilm. It also shows
how knowledge of religious law can be obtained. Al-Shafi`i's approach is to restrict
the argument to knowledge of specialised and debatable points, rather than what is
generally accepted. He seeks to prove the indispensability in this area of specialists'
knowledge of reliable documentation external to the law itself. The following chapter
deals with the question of authenticating a khabar from the Prophet (a hadith), not as
purely technical question but within a polemical context in which the practical
difficulty of authenticating a khabar was used by those opposed to the intellectual
dominance of oral tradition as a reason not to use the khabar. In the final chapter al-
Shaf i's arguments with two identifiable schools of opposing thought, ahl al-kaläm
and ahl al-figh, are examined in detail. The thesis as a whole gives a significant
insight into the efficacy and durability of al-Shafi`i's arguments, not so much by
defeating his opponents' arguments but by buttressing those of the defenders and
advocates of oral tradition
Il recupero del tessuto storico: il caso studio di Mirza Shafi street a Tbilisi, Georgia
No full textLa grande ricchezza culturale che caratterizza l’Europa è un prezioso risultato derivato dalla convivenza e dal confronto tra differenti popo- lazioni, tradizioni, identità nazionali e regionali. Ciò che noi oggi osserviamo è, infatti, il risultato di un’identità collettiva complessa, derivata da influenze culturali comunitarie e non-comunitarie che, nello sviluppo tecnologico degli ultimi decenni in termi- ni di scambio di flussi di informazioni tra persone, hanno visto un incremento esponenziale. In tale contesto di fluidità e permeabilità dei confini, è necessario leggere l’esperienza didattico-formativa condotta durante il workshop “Re-development of Urban Fabric: the case Study Mirza Shafi street”, svolto a Settembre 2016 presso la Tbilisi State Academy of Arts, in collaborazione con il Dipartimento di Architettura dell’Università degli Studi di Ferrara. Grazie a tale collaborazione internazionale è stata infatti individuata la possibilità di condurre uno studio approfondito su uno dei temi urbani che più caratterizzano, allo stato attuale, la città di Tbilisi (თბილისი), capitale e maggiore città della Georgia
Bipartite Perfect Matching in Pseudo-Deterministic NC
No full textWe present a pseudo-deterministic NC algorithm for finding perfect matchings in bipartite graphs. Specifically, our algorithm is a randomized parallel algorithm which uses poly(n) processors, poly(log n) depth, poly(log n) random bits, and outputs for each bipartite input graph a unique perfect matching with high probability. That is, on the same graph it returns the same matching for almost all choices of randomness. As an immediate consequence we also find a pseudo-deterministic NC algorithm for constructing a depth first search (DFS) tree. We introduce a method for computing the union of all min-weight perfect matchings of a weighted graph in RNC and a novel set of weight assignments which in combination enable isolating a unique matching in a graph.
We then show a way to use pseudo-deterministic algorithms to reduce the number of random bits used by general randomized algorithms. The main idea is that random bits can be reused by successive invocations of pseudo-deterministic randomized algorithms. We use the technique to show an RNC algorithm for constructing a depth first search (DFS) tree using only O(log^2 n) bits whereas the previous best randomized algorithm used O(log^7 n), and a new sequential randomized algorithm for the set-maxima problem which uses fewer random bits than the previous state of the art.
Furthermore, we prove that resolving the decision question NC = RNC, would imply an NC algorithm for finding a bipartite perfect matching and finding a DFS tree in NC. This is not implied by previous randomized NC search algorithms for finding bipartite perfect matching, but is implied by the existence of a pseudo-deterministic NC search algorithm
The Complexity of Problems in P Given Correlated Instances
No full textInstances of computational problems do not exist in isolation. Rather, multiple and correlated instances of the same problem arise naturally in the real world. The challenge is how to gain computationally from correlations when they can be found.
[DGH, ITCS 2015] showed that significant computational gains can be made by having access to auxiliary instances which are correlated to the primary problem instance via the solution space. They demonstrate this for constraint satisfaction problems, which are NP-hard in the general worst case form.
Here, we set out to study the impact of having access to correlated instances on the complexity of polynomial time problems. Namely, for a problem P that is conjectured to require time n^c for c>0,
we ask whether access to a few instances of P that are correlated in some natural way can be used to solve P on one of them (the designated "primary instance") faster than the conjectured lower bound of n^c.
We focus our attention on a number of problems: the Longest Common Subsequence (LCS), the minimum Edit Distance between sequences, and Dynamic Time Warping Distance (DTWD) of curves, for all of which the best known algorithms achieve O(n^2/polylog(n)) runtime via dynamic programming. These problems form an interesting case in point to study, as it has been shown that a O(n^(2 - epsilon)) time algorithm for a worst-case instance would imply improved algorithms
for a host of other problems as well as disprove complexity hypotheses such as the Strong Exponential Time Hypothesis.
We show how to use access to a logarithmic number of auxiliary correlated instances, to design novel o(n^2) time algorithms for LCS, EDIT, DTWD, and more generally improved algorithms for computing any tuple-based similarity measure - a generalization which we define within on strings. For the multiple sequence alignment problem on k strings, this yields an O(nk\log n) algorithm
contrasting with classical O(n^k) dynamic programming.
Our results hold for several correlation models between the primary and the auxiliary instances. In the most general correlation model we address, we assume that the primary instance is a worst-case instance and the auxiliary instances are chosen with uniform distribution subject to the constraint that their alignments are
epsilon-correlated with the optimal alignment of the primary instance. We emphasize that optimal solutions for the auxiliary instances will not generally coincide with optimal solutions for the worst case primary instance.
We view our work as pointing out a new avenue for looking for significant improvements for sequence alignment problems and
computing similarity measures, by taking advantage of access to sequences which are correlated through natural generating processes.
In this first work we show how to take advantage of mathematically inspired simple clean models of correlation - the intriguing question, looking forward, is to find correlation models which coincide with evolutionary models and other relationships and for which our approach to multiple sequence alignment gives provable guarantees
A Lightweight Controller for Autonomous Following of a Target Platform for Drones
No full textDrones or Unmanned Aerial Vehicles (UAVs) are providing interminable opportunities to capture high-quality video feeds that were previously impossible and have transformed the digital era. Many applications today require computer vision (CV) and machine learning (ML) techniques to extract the useful information captured from the onboard camera, and send it to an embedded controller that can make independent decisions. For instance, maneuvering the drone to follow a target platform by using only the onboard camera feed is critical in target tracking. Therefore, in this paper, we exploit the applicability of a low-computational embedded tracking controller to follow a target platform e.g. a car or pedestrian, and thus, react in real-time, adjusting the drone steering angles and velocity. We developed a system that enables drones to follow a target platform autonomously without requiring continuous human intervention on an embedded state-of-the-art STM32 Nucleo board. The system includes a lightweight controller that controls the drone's movement and enables it to track and follow a target platform accurately. To validate the performance of our embedded controller, we performed a number of experiments in an open-source AirSim simulator. The tracking controller footprint and memory consumption was less than 3%, and was able to reliably track and trail the target platform in different environmental conditions
Securing computation against continuous leakage
No full text30th Annual Cryptology Conference, Santa Barbara, CA, USA, August 15-19, 2010. ProceedingsWe present a general method to compile any cryptographic algorithm into one which resists side channel attacks of the only computation leaks information variety for an unbounded number of executions. Our method uses as a building block a semantically secure subsidiary bit encryption scheme with the following additional operations: key refreshing, oblivious generation of cipher texts, leakage resilience re-generation, and blinded homomorphic evaluation of one single complete gate (e.g. NAND). Furthermore, the security properties of the subsidiary encryption scheme should withstand bounded leakage incurred while performing each of the above operations.
We show how to implement such a subsidiary encryption scheme under the DDH intractability assumption and the existence of a simple secure hardware component. The hardware component is independent of the encryption scheme secret key. The subsidiary encryption scheme resists leakage attacks where the leakage is computable in polynomial time and of length bounded by a constant fraction of the security parameter.Israel Science Foundation (710267)United States-Israel Binational Science Foundation (710613)National Science Foundation (U.S.) (6914349)Weizmann KAMAR Gran
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Interactive Proofs for Verifying Machine Learning
No full textWe consider the following question: using a source of labeled data and interaction with an untrusted prover, what is the complexity of verifying that a given hypothesis is "approximately correct"? We study interactive proof systems for PAC verification, where a verifier that interacts with a prover is required to accept good hypotheses, and reject bad hypotheses. Both the verifier and the prover are efficient and have access to labeled data samples from an unknown distribution. We are interested in cases where the verifier can use significantly less data than is required for (agnostic) PAC learning, or use a substantially cheaper data source (e.g., using only random samples for verification, even though learning requires membership queries). We believe that today, when data and data-driven algorithms are quickly gaining prominence, the question of verifying purported outcomes of data analyses is very well-motivated.
We show three main results. First, we prove that for a specific hypothesis class, verification is significantly cheaper than learning in terms of sample complexity, even if the verifier engages with the prover only in a single-round (NP-like) protocol. Moreover, for this class we prove that single-round verification is also significantly cheaper than testing closeness to the class. Second, for the broad class of Fourier-sparse boolean functions, we show a multi-round (IP-like) verification protocol, where the prover uses membership queries, and the verifier is able to assess the result while only using random samples. Third, we show that verification is not always more efficient. Namely, we show a class of functions where verification requires as many samples as learning does, up to a logarithmic factor
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