1,813 research outputs found

    Deterministic and Ensemble-Based Spatially-Coupled Product Codes

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    Several authors have proposed spatially-coupled (or convolutional-like) variants of product codes (PCs). In this paper, we focus on a parametrized family of generalized PCs that recovers some of these codes (e.g., staircase and block-wise braided codes) as special cases and study the iterative decoding performance over the binary erasure channel. Even though our code construction is deterministic (and not based on a randomized ensemble), we show that it is still possible to rigorously derive the density evolution (DE) equations that govern the asymptotic performance. The obtained DE equations are then compared to those for a related spatially-coupled PC ensemble. In particular, we show that there exists a family of (deterministic) braided codes that follows the same DE equation as the ensemble, for any spatial length and coupling width.Comment: accepted at ISIT 2016, Barcelona, Spai

    Density Evolution for Deterministic Generalized Product Codes with Higher-Order Modulation

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    Generalized product codes (GPCs) are extensions of product codes (PCs) where coded bits are protected by two component codes but not necessarily arranged in a rectangular array. It has recently been shown that there exists a large class of deterministic GPCs (including, e.g., irregular PCs, half-product codes, staircase codes, and certain braided codes) for which the asymptotic performance under iterative bounded-distance decoding over the binary erasure channel (BEC) can be rigorously characterized in terms of a density evolution analysis. In this paper, the analysis is extended to the case where transmission takes place over parallel BECs with different erasure probabilities. We use this model to predict the code performance in a coded modulation setup with higher-order signal constellations. We also discuss the design of the bit mapper that determines the allocation of the coded bits to the modulation bits of the signal constellation.Comment: invited and accepted paper for the special session "Recent Advances in Coding for Higher Order Modulation" at the International Symposium on Turbo Codes & Iterative Information Processing, Brest, France, 201

    Problem Based Learning, Motivasi Belajar, Kemampuan Awal, Dan Hasil Belajar Siswa Smk

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    : Problem Based Learning, Learning Motivation, Prior Ability, and Learning Outcomes of SMK Students. The present study examines the influence of Problem Based Learning (PBL), learning motivation, and the prior ability of vocational school students. The study employed nonequivalent control group quasi exsperimental design. 75 eleventh graders in the academic year of 2012/2013 were randomly assigned into the experiment and control groups. A test was administered to assess the prior ability (entry behavior) and learning outcomes, and self-inventory was used to elicit the students\u27 learning motivation. The three-way analysis of variance shows that there was a significant difference between the students taught using the problem-based learning and those taught using the conventional method, between those with high learning motivation and those with low motivation, and between those with higher prior ability and those with low ability. Additionally, there was significant interaction among teaching-learning models, learning motivation, and prior ability

    Pengaruh Model Pembelajaran Problem Based Learning (Pbl) Dan Bakat Mekanik Terhadap Hasil Belajar Siswa Kelas X Mata Pelajaran Sistem Bahan Bakar Sepeda Motor Program Keahlian Teknik Sepeda Motor Di Smk PGRI 3 Malang

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    The learning about motorcycle fuel system is emphasizing on the understanding on the procedure of a work process. Students are expected to understand and to implement a process based on raw material. Therefore, students are assigned into two groups, which are: students who follow problem-based learning (PBL) model and those who consider conventional model. Each group is divided again into two sub-groups, which are students which high and low mechanical talent. The objective of research is to examine the significance of the difference of learning result of fuel system between students with PBL model and students with conventional learning by considering the mechanical talent as the characteristic of students. Method of research is quasi-experiment, while research design is non-equivalent control group design. Experiment group and control group are taken from the existing class with assignment random sampling. Data are collected with observation and test. It is analyzed using two-way ANOVA

    The internationalisation of the Spanish SME sector

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    As part of a wider research program, we analysed the theoretical framework and the recent developments of the process of internationalisation (transnationalisation) of the small- and medium-sized enterprises in Spain. The paper highlights the main trends and barriers of this internationalisation process. Methodology included document analyses, interviews, and the analyses of statistical databases

    The Percepción Smart Campus system

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    Ponènica presentada a IberSPEECH 2014, VIII Jornadas en Tecnología del Habla and IV Iberian SLTech Workshop, celebrat a Las Palmas de Gran Canaria els dies 19-21 de novembre de 2014This paper presents the capabilities of the Smart Campus system developed during the Percepcion project. The Smart Campus system is able to locate the user of the application in a limited environment, including indoor location. The system is able to show routes and data (using virtual reality) on the different elements of the environment. Speech queries could be used to locate places and get routes and information on that places

    Aquatic pollution may favor the success of the invasive species A. franciscana

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    The genus Artemia consists of several bisexual and parthenogenetic sibling species. One of them, A. franciscana, originally restricted to the New World, becomes invasive when introduced into ecosystems out of its natural range of distribution. Invasiveness is anthropically favored by the use of cryptobiotic eggs in the aquaculture and pet trade. The mechanisms of out-competition of the autochthonous Artemia by the invader are still poorly understood. Ecological fitness may play a pivotal role, but other underlying biotic and abiotic factors may contribute. Since the presence of toxicants in hypersaline aquatic ecosystems has been documented, our aim here is to study the potential role of an organophosphate pesticide, chlorpyrifos, in a congeneric mechanism of competition between the bisexual A. franciscana (AF), and one of the Old World parthenogenetic siblings, A. parthenogenetica (PD). For this purpose we carried out life table experiments with both species, under different concentrations of the toxicant (0.1, 1 and 5 μg/l), and analyzed the cholinesterase inhibition at different developmental stages. The results evidence that both, AF and PD, showed an elevated tolerance to high ranges of chlorpyrifos, but AF survived better and its fecundity was less affected by the exposure to the pesticide than that of PD. The higher fecundity of AF is a selective advantage in colonization processes leading to its establishment as NIS. Besides, under the potential selective pressure of abiotic factors, such as the presence of toxicants, its higher resistance in terms of survival and biological fitness also indicates out-competitive advantages.Spanish Ministry for Science and Innovation project, CGL2005-02306, CGL2008-04737-E

    Microtubules in Bacteria: Ancient Tubulins Build a Five-Protofilament Homolog of the Eukaryotic Cytoskeleton

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    Microtubules play crucial roles in cytokinesis, transport, and motility, and are therefore superb targets for anti-cancer drugs. All tubulins evolved from a common ancestor they share with the distantly related bacterial cell division protein FtsZ, but while eukaryotic tubulins evolved into highly conserved microtubule-forming heterodimers, bacterial FtsZ presumably continued to function as single homopolymeric protofilaments as it does today. Microtubules have not previously been found in bacteria, and we lack insight into their evolution from the tubulin/FtsZ ancestor. Using electron cryomicroscopy, here we show that the tubulin homologs BtubA and BtubB form microtubules in bacteria and suggest these be referred to as “bacterial microtubules” (bMTs). bMTs share important features with their eukaryotic counterparts, such as straight protofilaments and similar protofilament interactions. bMTs are composed of only five protofilaments, however, instead of the 13 typical in eukaryotes. These and other results suggest that rather than being derived from modern eukaryotic tubulin, BtubA and BtubB arose from early tubulin intermediates that formed small microtubules. Since we show that bacterial microtubules can be produced in abundance in vitro without chaperones, they should be useful tools for tubulin research and drug screening

    What could assistance robots learn from assistance dogs?

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    These studies are part of our broader project that aims at revealing relevant aspects of human-dog interactions, which could help to develop and test robot social behaviour. We suggest that the cooperation between assistance dogs and their disabled owners could serve as a model to design successful assistance robot–human interactions. In Study 1, we analysed the behaviour of 32 assistance dog–owner dyads performing a fetch and carry task. In addition to important typical behaviours (attracting attention, eye-contact, comprehending pointing gestures), we found differences depending on how experienced the dyad was and whether the owner used a wheel chair or not. In Study 2 we investigated the reactions of a subsample of dogs to unforeseen difficulties during a retrieving task. We revealed different types of communicative and displacement behaviours, and importantly, dogs showed a strong commitment to execute the insoluble task or at least their behaviours lent a “busy” appearance to them, which can attenuate the owners’ disappointment. We suggest that assistant robots should communicate their inability to solve a problem using simple behaviours (non-verbal vocalisation, orientation alternation), and/or could show displacement behaviours rather than simply not performing the task. In sum, we propose that assistant dogs’ communicative behaviours and problem solving strategies could inspire the development of the relevant functions and social behaviours of assistance robots

    DNA adducts in fish following an oil spill exposure

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    On 12 December 1999, one third of the load of the Erika tanker, amounting to about 10,000 t crude oil flowed into sea waters close to the French Atlantic Coast. This oil contained polycyclic aromatic compounds (PAC) that are known to be genotoxic. Genotoxic effects induce DNA adducts formation, which can thus be used as pollution biomarkers. Here, we assessed the genotoxic impact of the “Erika” oil spill by DNA adducts detection in the liver of immature fishes (Solea solea) from four locations of the French Brittany coasts. Two months after the spill, a high amount of DNA adducts was found in samples from all locations, amounting to 92–290 DNA adduct per 109 nucleotides. Then total DNA adduct levels decreased to reach about 50 adducts per 109 nucleotides nine months after the spill. In vitro experiments using human cell cultures and fish liver microsomes evidence the genotoxicity of the Erika fuel. They also prove the formation of reactive species able to create DNA adducts. Furthermore, in vitro and in vivo DNA adducts fingerprints are similar, thus confirming that DNA adducts are a result of the oil spill
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