Iterative Phase Optimization of Elementary Quantum Error Correcting Codes

Performing experiments on small-scale quantum computers is certainly a challenging endeavor. Many parameters need to be optimized to achieve high-fidelity operations. This can be done efficiently for operations acting on single qubits, as errors can be fully characterized. For multiqubit operations, though, this is no longer the case, as in the most general case, analyzing the effect of the operation on the system requires a full state tomography for which resources scale exponentially with the system size. Furthermore, in recent experiments, additional electronic levels beyond the two-level system encoding the qubit have been used to enhance the capabilities of quantum-information processors, which additionally increases the number of parameters that need to be controlled. For the optimization of the experimental system for a given task (e.g., a quantum algorithm), one has to find a satisfactory error model and also efficient observables to estimate the parameters of the model. In this manuscript, we demonstrate a method to optimize the encoding procedure for a small quantum error correction code in the presence of unknown but constant phase shifts. The method, which we implement here on a small-scale linear ion-trap quantum computer, is readily applicable to other AMO platforms for quantum-information processing.

Refletindo sobre a criação e a utilização do dicionário como estratégia de enriquecimento lexical no 1.º CEB

O presente relatório foi realizado no âmbito do Mestrado em Educação Pré-Escolar e Ensino do 1.º Ciclo do Ensino Básico. Encontra-se organizado em duas partes, a primeira parte referente à Dimensão Reflexiva e a segunda parte à Dimensão Investigativa. A primeira parte consiste na apresentação do percurso vivenciado nos contextos de Educação de Infância e de 1.º Ciclo do Ensino Básico, fazendo uma análise crítica, reflexiva e fundamentada das situações vividas que proporcionaram diversas aprendizagens a nível profissional, pessoal e social. A segunda parte consiste na apresentação de um estudo investigativo de caráter qualitativo desenvolvido numa turma de 2.º ano de escolaridade. Este estudo pretende perceber o impacto da criação e utilização do dicionário no desenvolvimento lexical dos alunos, tendo como objetivos: (i) Compreender o impacto da estratégia didática (dicionário) para o enriquecimento lexical; (ii) Perceber de que forma os alunos utilizam o dicionário quando o fazem com ou sem orientação do professor; (iii) Refletir sobre a utilização do dicionário como estratégia de enriquecimento lexical. Os dados recolhidos revelam que a estratégia utilizada teve um impacto positivo, na medida em que, o capital lexical da maioria dos alunos foi significativamente aumentado, contudo, é também evidente que os alunos utilizavam o dicionário com maior frequência quando o faziam com orientação do professor. Em relação à utilização do dicionário como estratégia de enriquecimento lexical revelou-se que turmas nos primeiros anos de escolaridade apresentam dificuldades na seleção dos significados adequados para cada contexto, sendo necessário treiná-las nesse sentido.

The framework of the virtual laser tracker - A systematic approach to the assessment of error sources and uncertainty in laser tracker measurement

Laser trackers have been widely used in many industries to meet increasingly high accuracy requirements. In laser tracker measurement, it is complex and difficult to perform an accurate error analysis and uncertainty evaluation. This paper firstly reviews the working principle of single beam laser trackers and state-of- The- Art of key technologies from both industrial and academic efforts, followed by a comprehensive analysis of uncertainty sources. A generic laser tracker modelling method is formulated and the framework of the virtual tracker is proposed. The VLS can be used for measurement planning, measurement accuracy optimization and uncertainty evaluation. The completed virtual laser tracking system should take all the uncertainty sources affecting coordinate measurement into consideration and establish an uncertainty model which will behave in an identical way to the real system. © Springer-Verlag Berlin Heidelberg 2010.

Using parent report to assess early lexical production in children exposed to more than one language

Limited expressive vocabulary skills in young children are considered to be the first warning signs of a potential Specific Language Impairment (SLI) (Ellis & Thal, 2008). In bilingual language learning environments, the expressive vocabulary size in each of the child’s developing languages is usually smaller compared to the number of words produced by monolingual peers (e.g. De Houwer, 2009). Nonetheless, evidence shows children’s total productive lexicon size across both languages to be comparable to monolingual peers’ vocabularies (e.g. Pearson et al., 1993; Pearson & Fernandez, 1994). Since there is limited knowledge as to which level of bilingual vocabulary size should be considered as a risk factor for SLI, the effects of bilingualism and language-learning difficulties on early lexical production are often confounded. The compilation of profiles for early vocabulary production in children exposed to more than one language, and their comparison across language pairs, should enable more accurate identification of vocabulary delays that signal a risk for SLI in bilingual populations. These considerations prompted the design of a methodology for assessing early expressive vocabulary in children exposed to more than one language, which is described in the present chapter. The implementation of this methodological framework is then outlined by presenting the design of a study that measured the productive lexicons of children aged 24-36 months who were exposed to different language pairs, namely Maltese and English, Irish and English, Polish and English, French and Portuguese, Turkish and German as well as English and Hebrew. These studies were designed and coordinated in COST Action IS0804 Working Group 3 (WG3) and will be described in detail in a series of subsequent publications. Expressive vocabulary size was measured through parental report, by employing the vocabulary checklist of the MacArthur-Bates Communicative Development Inventory: Words and Sentences (CDI: WS) (Fenson et al., 1993, 2007) and its adaptations to the participants’ languages. Here we describe the novelty of the study’s methodological design, which lies in its attempt to harmonize the use of vocabulary checklist adaptations, together with parental questionnaires addressing language exposure and developmental history, across participant groups characterized by different language exposure variables. This chapter outlines the various methodological considerations that paved the way for meaningful cross-linguistic comparison of the participants’ expressive lexicon sizes. In so doing, it hopes to provide a template for and encourage further research directed at establishing a threshold for SLI risk in children exposed to more than one language.

Justificación y error en Descartes: un argumento pragmatista en la validación cartesiana del criterio de claridad y distinción

La percepción clara y distinta es el elemento sobre el que se asienta la certeza metafísica de Descartes. Con todo, el planteamiento de los argumentos escépticos referidos a la duda metódica cartesiana ha evidenciado la necesidad de hallar una justificación al propio criterio de la percepción clara y distinta. Frente a los intentos basados en la indubitabilidad de la percepción o en la garantía surgida de la bondad divina, se defenderá una justificación alternativa pragmatista.

From "ecological tourism" to "ecotourism": lexical analysis of an emerging tourism

From ecological tourism to ecotourism: lexical analysis of an emerging tourism. This article deals with the lexicon created in connection with a recent form of tourism: the ecological tourism or ecotourism. The rise of this type of tourism encourages the creation of new concepts and products that are named with new words and expressions with different procedures of formation. From the name itself ecotourism, then expressed as the acronym ecotourism, we analyze the formation of other related words, as well as their formal variation and use. For this, we have worked with a specific corpus of electronic tourist texts and different digital sources and databases.

A low overhead error confinement method based on application statistical characteristics

Reliability has emerged as a critical design constraint especially in memories. Designers are going to great lengths to guarantee fault free operation of the underlying silicon by adopting redundancy-based techniques, which essentially try to detect and correct every single error. However, such techniques come at a cost of large area, power and performance overheads which making many researchers to doubt their efficiency especially for error resilient systems where 100% accuracy is not always required. In this paper, we present an alternative method focusing on the confinement of the resulting output error induced by any reliability issues. By focusing on memory faults, rather than correcting every single error the proposed method exploits the statistical characteristics of any target application and replaces any erroneous data with the best available estimate of that data. To realize the proposed method a RISC processor is augmented with custom instructions and special-purpose functional units. We apply the method on the proposed enhanced processor by studying the statistical characteristics of the various algorithms involved in a popular multimedia application. Our experimental results show that in contrast to state-of-the-art fault tolerance approaches, we are able to reduce runtime and area overhead by 71.3% and 83.3% respectively.

Energy efficiency in the Chinese provinces: a fixed effects stochastic frontier spatial Durbin error panel analysis

Energy efficiency improvement has been a key objective of China’s long-term energy policy. In this paper, we derive single-factor technical energy efficiency (abbreviated as energy efficiency) in China from multi-factor efficiency estimated by means of a translog production function and a stochastic frontier model on the basis of panel data on 29 Chinese provinces over the period 2003–2011. We find that average energy efficiency has been increasing over the research period and that the provinces with the highest energy efficiency are at the east coast and the ones with the lowest in the west, with an intermediate corridor in between. In the analysis of the determinants of energy efficiency by means of a spatial Durbin error model both factors in the own province and in first-order neighboring provinces are considered. Per capita income in the own province has a positive effect. Furthermore, foreign direct investment and population density in the own province and in neighboring provinces have positive effects, whereas the share of state-owned enterprises in Gross Provincial Product in the own province and in neighboring provinces has negative effects. From the analysis it follows that inflow of foreign direct investment and reform of state-owned enterprises are important policy handles.

Du Bois's Prolific "Error" and the Break with Color-Blind Orthodoxy

Contribution to a roundtable on the 70th anniversary of the publication of W. E. B. DuBois's classic study of US slave emancipation, Black Reconstruction, 1860-1880, including original research on the context in which the book was launched and reflections on its impact on the recent historiography of the American Civil War and its aftermath. 

Improving Readability of Swedish Electronic Health Records through Lexical Simplification : First Results

This paper describes part of an ongoing effort to improve the readability of Swedish electronic health records (EHRs). An EHR contains systematic documentation of a single patient’s medical history across time, entered by healthcare professionals with the purpose of enabling safe and informed care. Linguistically, medical records exemplify a highly specialised domain, which can be superficially characterised as having telegraphic sentences involving displaced or missing words, abundant abbreviations, spelling variations including misspellings, and terminology. We report results on lexical simplification of Swedish EHRs, by which we mean detecting the unknown, out-ofdictionary words and trying to resolve them either as compounded known words, abbreviations or misspellings.

Bilingual Lexical Access in Reading : Analyzing the Effect of Semantic Context on Non-Selective Access in Bilingual Memory

Recent empirical studies about the neurological executive nature of reading in bilinguals differ in their evaluations of the degree of selective manifestation in lexical access as implicated by data from early and late reading measures in the eye-tracking paradigm. Currently two scenarios are plausible: (1) Lexical access in reading is fundamentally language non-selective and top-down effects from semantic context can influence the degree of selectivity in lexical access; (2) Cross-lingual lexical activation is actuated via bottom-up processes without being affected by top-down effects from sentence context. In an attempt to test these hypotheses empirically, this study analyzed reader-text events arising when cognate facilitation and semantic constraint interact in a 22 factorially designed experiment tracking the eye movements of 26 Swedish-English bilinguals reading in their L2. Stimulus conditions consisted of high- and low-constraint sentences embedded with either a cognate or a non-cognate control word. The results showed clear signs of cognate facilitation in both early and late reading measures and in either sentence conditions. This evidence in favour of the non-selective hypothesis indicates that the manifestation of non-selective lexical access in reading is not constrained by top-down effects from semantic context.