Miracle-dz/UniFAR-FTUs huggingface dataset:
An Analysis of Attacks on Blockchain Consensus

We present and validate a novel mathematical model of the blockchain mining process and use it to conduct an economic evaluation of the double-spend attack, which is fundamental to all blockchain systems. Our analysis focuses on the value of transactions that can be secured under a conventional double-spend attack, both with and without a concurrent eclipse attack. Our model quantifies the importance of several factors that determine the attack's success, including confirmation depth, attacker mining power, and any confirmation deadline set by the merchant. In general, the security of a transaction against a double-spend attack increases roughly logarithmically with the depth of the block, made easier by the increasing sum of coin turned-over (between individuals) in the blocks, but more difficult by the increasing proof of work required. In recent blockchain data, we observed a median block turnover value of 6 BTC. Based on this value, a merchant requiring a single confirmation is protected against only attackers that can increase the current mining power by 1% or less. However, similar analysis shows that a merchant that requires a much longer 72 confirmations (~12 hours) will eliminate all potential profit for any double-spend attacker adding mining power less than 40% of the current mining power.
Simple and tight device-independent security proofs

Device-independent security is the gold standard for quantum cryptography: not only is security based entirely on the laws of quantum mechanics, but it holds irrespective of any a priori assumptions on the quantum devices used in a protocol, making it particularly applicable in a quantum-wary environment. While the existence of device-independent protocols for tasks such as randomness expansion and quantum key distribution has recently been established, the underlying proofs of security remain very challenging, yield rather poor key rates, and demand very high quality quantum devices, thus making them all but impossible to implement in practice. We introduce a technique for the analysis of device-independent cryptographic protocols. We provide a flexible protocol and give a security proof that provides quantitative bounds that are asymptotically tight, even in the presence of general quantum adversaries. At a high level our approach amounts to establishing a reduction to the scenario in which the untrusted device operates in an identical and independent way in each round of the protocol. This is achieved by leveraging the sequential nature of the protocol and makes use of a newly developed tool, the “entropy accumulation theorem” of Dupuis, Fawzi, and Renner [Entropy Accumulation, preprint, 2016]. As concrete applications we give simple and modular security proofs for device-independent quantum key distribution and randomness expansion protocols based on the CHSH inequality. For both tasks, we establish essentially optimal asymptotic key rates and noise tolerance. In view of recent experimental progress, which has culminated in loophole-free Bell tests, it is likely that these protocols can be practically implemented in the near future.
Ethnolinguistic diversity within Australian schools: call for a participant perspective in teacher learning

Abstract Enactment of policy on diversity and learning in Australian schools is evident in “diversity talk” in daily discourses of school teachers. From policy documents to daily staffroom conversations, there is extensive use in contemporary Western educational discourse of ethnolinguistic categories. The categorization of students to groups on the basis of cultural and linguistic attributes can potentially be counter-productive to school learning and broader practices of intercultural understanding. In this paper we critique policy-derived categorizations in Australia that encourage teachers’ perceptions of themselves as outside, rather than as participants in, the dynamic interplay of variables that characterize contemporary society. We call for increased opportunities in teacher education and teacher professional development in the areas of cultural identity and shifting cultural ethnoscapes as a basis for contextually responsive and pedagogically viable enactment of procedures and practices mandated by current policy settings with the aim of students from ethnolinguistically diverse backgrounds achieving their potential as participants in the broader community.
A Model Driven Service Identification Approach for Process Centric Systems

The raison dpsilaetre for Web-services is that they could be used to compose new services. As in process centric systems, wherein blocks of software implement a functional domain through a set of linked activities, a SOA based system modeled through Web-services, requires business services (of low granularity) which implement various business functions. Such business services could not only ensure a high degree of re-use but could also help in realizing service oriented architecture in its true sense. Although today quite a few approaches for the problem exist, but most of them are bottom up solutions, or mainly focus on domain decomposition and composite service formation. Not many of them have yet utilized the full potential of business processes, which form the backbone of any enterprise. In this work we define what a business service would be like, vis-a-vis its corresponding business function, and how it could be realized through data, utility, information and other services. We present our service identification approach which utilizes process maps and service hierarchies and towards the end we discuss some of our current work in building an automation tool (named SQUID) for service identification.
Learning how to approach industrial robot tasks from natural demonstrations

In the last years, Robot Learning from Demonstration (RLfD) [1] [2] has become a major topic in robotics research. The main reason for this is that programming a robot can be a very difficult and time spending task. The RLfD paradigm has been applied to a great variety of robots, but it is still difficult to make the robot learn a task properly. Often the teacher is not an expert in the field, and viceversa an expert could not know well enough the robot to be a teacher. With this paper, we aimed at closing this gap by proposing a novel motion re-targeting technique to make a manipulator learn from natural demonstrations. A RLfD framework based on Gaussian Mixture Models (GMM) and Gaussian Mixture Regressions (GMR) was set to test the accuracy of the system in terms of precision and repeatability. The robot used during the experiments is a Comau Smart5 SiX and a novel virtual model of this manipulator has also been developed to simulate an industrial scenario which allows valid experimentation while avoiding damages to the real robot.
Effect of Environmental Disturbance on the Population of Sandflies and Leishmania Transmission in an Endemic Area of Venezuela

The exploitation of new wilderness areas with crops is increasing and traditional crop substitution has been modified by new more productive crops. The results show the anthropogenic disturbance effect on the sandflies population and Leishmania transmission in endemic areas of Venezuela. Three agroecosystems with variable degrees of ecological disturbance, forest (conserved), cacao (fragmented), and orangery (disturbed), were selected. Four methods to sandfly capture were used; the specimens were identified and infected with Leishmania. Diversity, population structure, ANOVA, Tukey test, and simple correlation analysis were carried out. Shannon traps were able to capture 94.7% of the total sandflies, while CDC light traps, Sticky traps, and direct suction just captured 2.2%, 1.2%, and 0.9%, respectively. The results showed the effect of ecological disturbance degree on the composition of sandflies and population structure, revealing a dominance level increased but decreased on the diversity and richness of sandflies species in the greatest ecological disturbance area in relation to areas with less organic disturbance. Environments more disturbed cause adaptability of certain species such as Lutzomyia gomezi and Lutzomyia walkeri. These changes on the composition of sandflies population and structure emerging species could cause increasing of leishmaniasis transmission.
Capture‐C reveals preformed chromatin interactions between HIF‐binding sites and distant promoters

Hypoxia‐inducible factor (HIF) directs an extensive transcriptional cascade that transduces numerous adaptive responses to hypoxia. Pan‐genomic analyses, using chromatin immunoprecipitation and transcript profiling, have revealed large numbers of HIF‐binding sites that are generally associated with hypoxia‐inducible transcripts, even over long chromosomal distances. However, these studies do not define the specific targets of HIF‐binding sites and do not reveal how induction of HIF affects chromatin conformation over distantly connected functional elements. To address these questions, we deployed a recently developed chromosome conformation assay that enables simultaneous high‐resolution analyses from multiple viewpoints. These assays defined specific long‐range interactions between intergenic HIF‐binding regions and one or more promoters of hypoxia‐inducible genes, revealing the existence of multiple enhancer–promoter, promoter–enhancer, and enhancer–enhancer interactions. However, neither short‐term activation of HIF by hypoxia, nor long‐term stabilization of HIF in von Hippel–Lindau (VHL)‐defective cells greatly alters these interactions, indicating that at least under these conditions, HIF can operate on preexisting patterns of chromatin–chromatin interactions that define potential transcriptional targets and permit rapid gene activation by hypoxic stress.
Automatic image vectorization using superpixels and random walkers

Image vectorization involves two major problems: how to extract proper geometric descriptors from the raster image and how to rasterize the vector representation for display. In this paper, we propose a novel image vectorization approach using diffusion curves as the geometric primitives. Our approach automatically extracts accurate diffusion curves from the input image without user interaction. We first segment the input image into a set of superpixels by a multi-layer algorithm. Then, boundary positions of these superpixels are explored to locate control points for diffusion curves, and color information is properly sampled to generate our double-boundary representation. To render the vector graphics, we formulate color diffusion as a random walk process. Experiments on different categories of photographs show that our approach successfully reveals detail contents in the reconstructed image, and that the rendering process can be performed nearly in realtime on a modern CPU.
A Generalization of the Pfähler-Lambert Decomposition

The aim of this paper is to provide a generalization of the Pfahler (1990) and Lambert (1989, 2001) decomposition, which allows us to overcome some limitations of the original methodology. In particular, our proposal avoids the problem of sequentiality when the tax has several types of deductions or allowances, schedules or tax credits. In addition, our alternative decomposition is adapted to the dual income class of tax structures. Moreover, in order to adapt this methodology to real-world taxes, our approach includes the re-ranking effects of real taxes, caused by the existence of differentiated treatments based on non-income attributes. This theoretical proposal is illustrated with an empirical analysis for the Spanish Personal Income Tax reform enforced in 2007.
Small Sample Properties of Matching with Calliper

A caliper mechanism is a common tool used to prevent from inexact matches. The existing literature discusses asymptotic properties of matching with caliper. In this simulation study we investigate properties in small and medium sized samples. We show that caliper causes a significant bias of the ATT estimator and raises its variance in comparison to one-to-one matching.
Evaluation of Ag-sinter pastes for the die attachment in power electronic modules using design of experiments

Silver sintering is a potential die attach technology to replace the solder technology for power electronic systems. A design of experiments (DoE) is performed in order to investigate the influences of sinter parameters as sinter pressure, temperature, duration, drying temperature and the interactions of these parameters on the shear strength of the Ag-sinter connection. Four sinter pastes have been evaluated. All significant parameters and parameter interactions are identified in order to derive a quadratic model function used to fit the measured shear values. This fitted function predicts the shear strength as a function of the significant parameters and, moreover, the function is used to determine the optimal sinter parameter space. The shear tests reveal that for three tested sinter pastes an excellent average shear result exceeding 90 MPa is achieved. One sinter paste outperforms these results by an average shear strength of 121 MPa. The DoE shows that all sinter pastes are significantly dependent on the sinter pressure and sinter temperature. However one sinter paste is influenced by the drying temperature and a second sinter paste is independent of the drying temperature as well as the sinter duration.
Elevated Blood Pressure among Rural South African Children in Thohoyandou, South Africa

Background Whilst there seem to be available data on blood pressure profiles of South African children, especially in urban areas, few data exist on rural children. The aims of this study were to determine the blood pressure profiles of rural South African children residing in Thohoyandou; and to examine the relationship between body mass index and blood pressure among the children. Methods: The study involved 296 (134 boys and 135 girls) children aged 7–13 years. Body weight and height were measured using standard procedures. Overweight was defined by body mass index (BMI) for gender and age. Blood pressure was monitored in each child thrice using validated electronic devices (Omron 7051T). Hypertension was determined as the average of three separate blood pressure readings where the systolic or diastolic blood pressure was ≥ 90th percentile for age and sex. Results: Overweight among the girls (4.7%) was higher compared with the boys (3.9%). Both systolic and diastolic pressures (SBP and DBP) increase with age in both sexes. The proportion of children with > 90th percentile occur at only ages 12 and 13 years. The incidence of hypertension (SBP > 90th percentile) was 0.4% and 0.2% in boys and girls, respectively. The SBP and DBP pressures significantly (P<0.05) correlate with age; body mass, height and BMI. Conclusion: Elevated blood pressure is prevalent among rural South African children residing in this region. Also, blood pressure increased with age in both boys and girls, and this positively correlated with age, body weight, height and BMI.
Data Mining in the Context of Entity Resolution

We have encountered several practical issues in performing data mining on a database that has been normalized using entity resolution. We describe here four specific lessons learned in such mining and the meta-level lesson learned through dealing with these issues. The four specific lessons we describe deal with handling correlated values, getting canonical records, getting authoritative records and ensuring that relations are properly stored. The perhaps most important lesson learned is that one ought to know the kind of data mining is to be done on the data before designing the schema of the normalized database such that data specific to the mining is derivable from the database.
Automatic Grading of Programming Exercises using Property-Based Testing

We present a framework for automatic grading of programming exercises using property-based testing, a form of model-based black-box testing. Models are developed to assess both the functional behaviour of programs and their algorithmic complexity. From the functional correctness model a large number of test cases are derived automatically. Executing them on the body of exercises gives rise to a (partial) ranking of programs, so that a program A is ranked higher than program B if it fails a strict subset of the test cases failed by B. The model for algorithmic complexity is used to compute worst-case complexity bounds. The framework moreover considers code structural metrics, such as McCabe's cyclomatic complexity, giving rise to a composite program grade that includes both functional, non-functional, and code structural aspects. The framework is evaluated in a course teaching algorithms and data structures using Java.
Long-Term and Transgenerational Effects of Stress Experienced during Different Life Phases in Chickens (Gallus gallus)

Stress in animals causes not only immediate reactions, but may affect their biology for long periods, even across generations. Particular interest has been paid to perinatal stress, but also adolescence has been shown to be a sensitive period in mammals. So far, no systematic study has been performed of the relative importance of stress encountered during different life phases. In this study, groups of chickens were exposed to a six-day period of repeated stress during three different life phases: early (two weeks), early puberty (eight weeks) and late puberty (17 weeks), and the effects were compared to an unstressed control group. The short-term effects were assessed by behaviour, and the long-term and transgenerational effects were determined by effects on behavior and corticosterone secretion, as well as on hypothalamic gene expression. Short-term effects were strongest in the two week group and the eight week group, whereas long-term and transgenerational effects were detected in all three stress groups. However, stress at different ages affected different aspects of the biology of the chickens, and it was not possible to determine a particularly sensitive life phase. The results show that stress during puberty appears to be at least equally critical as the previously studied early life phase. These findings may have important implications for animal welfare in egg production, since laying hens are often exposed to stress during the three periods pinpointed here.
Tamil Merchant in Ancient Mesopotamia

Recent analyses of ancient Mesopotamian mitochondrial genomes have suggested a genetic link between the Indian subcontinent and Mesopotamian civilization. There is no consensus on the origin of the ancient Mesopotamians. They may be descendants of migrants, who founded regional Mesopotamian groups like that of Terqa or they may be merchants who were involved in trans Mesopotamia trade. To identify the Indian source population showing linkage to the ancient Mesopotamians, we screened a total of 15,751 mitochondrial DNAs (11,432 from the literature and 4,319 from this study) representing all major populations of India. Our results although suggest that south India (Tamil Nadu) and northeast India served as the source of the ancient Mesopotamian mtDNA gene pool, mtDNA of these ancient Mesopotamians probably contributed by Tamil merchants who were involved in the Indo-Roman trade.
A distributed anonymization scheme for privacy-preserving recommendation systems

Recommendation systems need to collect user personal data for predicting user preferences. The privacy of user personal data becomes a main concern when users are served by the recommendation system. In this paper, we study the problem of privacy-preserving recommendation in the case that the user data are locally stored in a distributed manner. We present a distributed anonymization scheme based on the proposed anonymization map. The proposed scheme allows users individually anonymize their own data without accessing each other's data. The experiment results show that the proposed scheme can preserve the privacy of collaborative users and outperform the perturbation-based scheme.
Proper PIN1 Distribution Is Needed for Root Negative Phototropism in Arabidopsis

Plants can be adapted to the changing environments through tropic responses, such as light and gravity. One of them is root negative phototropism, which is needed for root growth and nutrient absorption. Here, we show that the auxin efflux carrier PIN-FORMED (PIN) 1 is involved in asymmetric auxin distribution and root negative phototropism. In darkness, PIN1 is internalized and localized to intracellular compartments; upon blue light illumination, PIN1 relocalize to basal plasma membrane in root stele cells. The shift of PIN1 localization induced by blue light is involved in asymmetric auxin distribution and root negative phototropic response. Both blue-light-induced PIN1 redistribution and root negative phototropism is mediated by a BFA-sensitive trafficking pathway and the activity of PID/PP2A. Our results demonstrate that blue-light-induced PIN1 redistribution participate in asymmetric auxin distribution and root negative phototropism.
LP based approach to optimal stable matchings

We study the classical stable marriage and stable roommates problems using a polyhedral approach. We propose a new LP formulation for the stable roommates problem. This formulation is non-empty if and only if the underlying roommates problem has a stable matching. Furthermore, for certain special weight functions on the edges, we construct a 2-approximation algorithm for the optimal stable roommates problem. Our technique uses a crucial geometry of the fractional solutions in this formulation. For the stable marriage problem, we show that a related geometry allows us to express any fractional solution in the stable marriage polytope as convex combination of stable marriage solutions. This leads to a genuinely simple proof of the integrality of the stable marriage polytope. Based on these ideas, we devise a heuristic to solve the optimal stable roommates problem. The heuristic combines the power of rounding and cutting-plane methods. We present some computational results based on preliminary implementations of this heuristic.
Wages and prices: Are workers fully compensated for cost of living differences?

This paper investigates the equilibrium relationship between wages and prices across labor markets. Of central interest is the extent to which workers receive higher wages to compensate for differences in the cost of living. According to the spatial equilibrium hypothesis, the utility of homogenous workers should be equal across labor markets. This implies that controlling for amenity differences across areas, the elasticity between wages and the general price level across areas should equal one, at least under certain conditions. I test this hypothesis and find that the predicted relationship holds when housing prices are measured by rents and the general price level is instrumented to account for measurement error. When housing prices are measured by housing values, however, the wage-price elasticity is significantly less than one, even using instrumental variables. Rents reflect the price paid for housing per unit of time and are arguably the superior measure. Thus, findings in this essay provide support for the full compensation hypothesis. These findings also have important implications for researchers estimating the implicit prices of amenities or ranking the quality of life across areas. JEL Classification: R23, R20, J31