Miracle-dz/UniFAR-FTUs huggingface dataset:
Data-Driven Insights into Non-Purchasing Behaviours through Latent Dirichlet Allocation: Analysing Study Material Acquisition Among University Students

The advent of technology has shifted higher education students’ educational resource acquisition from traditional printed textbooks to digital formats. This shift is underscored by recent scholarship. The current study extended the discourse on student educational resource acquisition, beyond digital preference. It offers a nuanced view of strategies encompassing digital resources and traditional methods such as library and peer borrowing. The aim of this study was to investigate non-purchasing behaviours of university students in acquiring study material. An online survey link was sent through email to all registered students in the university, out of which a total of 1500 participated – this sample included all students from the four schools. The survey sought to answer the following questions: How do you access books? Besides buying, what other strategies have you employed to access books? Data were analysed using Dirichlet allocation for topic modelling to extract the topics from participants' qualitative responses. The study’s findings reveal a complex interplay of socio-economic factors that influence student behaviour. Digital downloads emerged as a prominent strategy, indicating a reliance on online resources. However, borrowing from libraries and peers was significant, which highlights the role of social learning communities. This study contributes to the understanding of how the cost of textbooks impacts academic choices and success, emphasising the social justice implications of textbook affordability. The rise of alternative media suggests a need to reimagine educational resources. It potentially reflects a generational shift in media consumption. This study’s insights advocate for educational institutions and policymakers to reassess resource provisioning to align with the evolving landscape of higher education students’ academic resource acquisition. This will ensure equitable access to educational material.
A Tutorial on the Expectation-Maximization Algorithm Including Maximum-Likelihood Estimation and EM Training of Probabilistic Context-Free Grammars

The paper gives a brief review of the expectation-maximization algorithm (Dempster 1977) in the comprehensible framework of discrete mathematics. In Section 2, two prominent estimation methods, the relative-frequency estimation and the maximum-likelihood estimation are presented. Section 3 is dedicated to the expectation-maximization algorithm and a simpler variant, the generalized expectation-maximization algorithm. In Section 4, two loaded dice are rolled. A more interesting example is presented in Section 5: The estimation of probabilistic context-free grammars.
Entropic Analysis of the Role of Words in Literary Texts

Beyond the local constraints imposed by grammar, words concatenated in long sequences carrying a complex message show statistical regularities that may reflect their linguistic role in the message. In this paper, we perform a systematic statistical analysis of the use of words in literary English corpora. We show that there is a quantitative relation between the role of content words in literary English and the Shannon information entropy defined over an appropriate probability distribution. Without assuming any previous knowledge about the syntactic structure of language, we are able to cluster certain groups of words according to their specific role in the text.
Household socio-economic status, social support and infant and child growth in urban South Africa: a cohort study from 1990

The rapid political, economic and social changes experienced by South Africans from 1991, combined with socio-economic inequalities ingrained in South African society at this time, made the early 1990s a unique and well-suited period to investigate child growth inequalities. Furthermore, recent estimates of low birth weight and stunting (≤ 3 years), showing prevalence of 15% (Chen et aI., 2006) and 25.5% (Labadarios, 1999) respectively, indicate that poor intrauterine and postnatal growth patterns continue to represent considerable public health issues in this setting. This study aimed to investigate associations of birth measures of household SES and social support with infant/child growth in urban South Africa. Anthropometric, demographic, socioeconomic and social support data for quantitative analyses were obtained from the 1990 Bt20 cohort (n=3275). [Continues. ]
Finding low-weight polynomial multiples using discrete logarithm

Finding low-weight multiples of a binary polynomial is a difficult problem arising in the context of stream ciphers cryptanalysis. The best algorithms to solve this problem are based on a time memory tradeoff. Staying in this category, we will present a new approach using discrete logarithm rather than a direct representation of the involved polynomials. This provides an alternative to the previously known algorithms which improves in some case the computational complexity.
Bottom Suspended Particulate Matter Dynamics in a Ría Environment Under Fair-Weather Conditions: Ría de Vigo (NW Spain)

ABSTRACT Lersundi-Kampistegui, A.V. ; Bernabeu, A.M.; Rey, D. , and Plaza-Morlote, M. , 2019. Bottom suspended particulate matter dynamics in a ría environment under fair-weather conditions: Ría de Vigo (NW Spain). Journal of Coastal Research, 35(2), 420–433. Coconut Creek (Florida), ISSN 0749-0208. The Ría de Vigo (NW Spain) is an economically important coastal system in which increasing demographic pressure over the last four decades has led to the development of conflicting economic activities, such as industry, fisheries, and tourism. The bottom sediment dynamics in the ría were investigated here for the first time as a key element to address effective coastal management in this context. The turbidity, salinity, temperature, and current were measured by two current meters placed at ∼1 m above the bottom (mab) during 14 days from 28 June 2005 to 11 July 2005. Both stations were placed in the marine sector of the ría, one in the central channel and the other in the outer southern margin. Superficial sediment samples in the surroundings of each site were also analyzed. The survey occurred under low-wave (significant wave height [Hs] < 2 m) conditions with little precipitation, typical of the summer season. The oceanographic observations registered the complete development of an East North Atlantic Central Water (ENACW) upwelling event in the ría. The results indicated that the main suspended particulate matter (SPM) fluctuation was produced in the subtidal timescale and correlated well with the upwelling-produced inward current, rather than with the dominant hydrodynamic processes (tide and waves) at the sampling sites. Punctual, but significant input from runoff was also detected in the channel. Under summer conditions, the advection of the shelf SPM by the upwelling bottom current stands out as the main transport process observed in the marine sector of the ría.
Decentralized Maximum-Likelihood Estimation for Sensor Networks Composed of Nonlinearly Coupled Dynamical Systems

In this paper, we propose a decentralized sensor network scheme capable to reach a globally optimum maximum-likelihood (ML) estimate through self-synchronization of nonlinearly coupled dynamical systems. Each node of the network is composed of a sensor and a first-order dynamical system initialized with the local measurements. Nearby nodes interact with each other exchanging their state value, and the final estimate is associated to the state derivative of each dynamical system. We derive the conditions on the coupling mechanism guaranteeing that, if the network observes one common phenomenon, each node converges to the globally optimal ML estimate. We prove that the synchronized state is globally asymptotically stable if the coupling strength exceeds a given threshold. Acting on a single parameter, the coupling strength, we show how, in the case of nonlinear coupling, the network behavior can switch from a global consensus system to a spatial clustering system. Finally, we show the effect of the network topology on the scalability properties of the network, and we validate our theoretical findings with simulation results.
A Reflective Approach to Providing Flexibility in Application Distribution

Current middleware systems suffer from drawbacks. Often one is forced to make decisions early in the design process about which classes may participate in inter-machine communication. Further, application level and middleware specific semantics cannot be separated, forcing an unnatural design. The RAFDA project proposes to address these deficiencies by creating an adaptive, reflective framework that enables the transformation of non-distributed applications into semantically equivalent applications whose distribution architecture is flexible. This paper describes the code transformation techniques that have been developed as part of the project. The system enables the distribution of a program according to a flexible configuration without user intervention. Remote and non-remote versions of an object become interchangeable. The distributed program can adapt to its environment by dynamically altering its distribution boundaries.
How to Evaluate Your Question Answering System Every Day ... and Still Get Real Work Done

In this paper, we report on Qaviar, an experimental automated evaluation system for question answering applications. The goal of our research was to find an automatically calculated measure that correlates well with human judges' assessment of answer correctness in the context of question answering tasks. Qaviar judges the response by computing recall against the stemmed content words in the humangenerated answer key. It counts the answer correct if it exceeds a given recall threshold. We determined that the answer correctness predicted by Qaviar agreed with the human 93% to 95% of the time. 41 question-answering systems were ranked by both Qaviar and human assessors, and these rankings correlated with a Kendall’s Tau measure of 0.920, compared to a correlation of 0.956 between human assessors on the same data.
The Association between Red Blood Cell Distribution Width and Mortality Risk after Hip Fracture: A Meta-Analysis

Background and Objectives: Hip fractures in the elderly pose a considerable health risk and cause concern. Red blood cell distribution width (RDW) is a valuable marker for identifying patients at high risk of age-related mortality and various disorders and diseases. However, its association with poor patient outcomes following hip fractures has yet to be fully established. Hence, the purpose of this meta-analysis was to investigate and gain a better understanding of the relationship between RDW levels and the risk of mortality after hip fractures. Materials and Methods: PubMed, Embase, Web of Science, and other databases were comprehensively searched until April 2023 to identify relevant studies. The meta-analysis included observational studies finding the association between RDW at admission or preoperation and short-term and long-term mortality rates following hip fractures. The results were presented in terms of odds ratios (ORs) or hazard ratios (HRs) with corresponding 95% confidence intervals (CIs). Results: This meta-analysis included 10 studies involving 5834 patients with hip fractures. Patients with preoperative RDW of over 14.5% had higher risks of 1-year (OR: 5.40, 95% CI: 1.89–15.48, p = 0.002) and 3-month (OR: 2.91, 95% CI: 1.42–5.95, p = 0.004) mortality. Higher admission or preoperative RDW was significantly associated with an 11% higher mortality risk after 1 year (HR: 1.11, 95% CI: 1.06–1.17, p < 0.00001). Patients with higher preoperative RDW had a significantly higher risk of 6-month mortality, which was three times that of those with lower preoperative RDW (OR: 3.00, 95% CI: 1.60–5.61, p = 0.0006). Higher preoperative RDW was correlated to a higher 30-day mortality risk (OR: 6.44, 95% CI: 3.32–12.47, p < 0.00001). Conclusions: Greater RDW values at admission or before surgery were associated with a higher risk of short-term and long-term mortality following hip fractures. Because RDW can be easily measured using a routine blood test at a low cost, this parameter is promising as an indicator of mortality in elderly patients with hip fractures.
Using sentence connectors for evaluating MT output

This paper elaborates on the design of a machine translation evaluation method that aims to determine to what degree the meaning of an original text is preserved in translation, without looking into the grammatical correctness of its constituent sentences. The basic idea is to have a human evaluator take the sentences of the translated text and, for each of these sentences, determine the semantic relationship that exists between it and the sentence immediately preceding it. In order to minimise evaluator dependence, relations between sentences are expressed in terms of the conjuncts that can connect them, rather than through explicit categories. For an n-sentence text this results in a list of n-1 sentence-to-sentence relationships, which we call the text's connectivity profile. This can then be compared to the connectivity profile of the original text, and the degree of correspondence between the two would be a measure for the quality of the translation.A set of "essential" conjuncts was extracted for English and Japanese, and a computer interface was designed to support the task of inserting the most fitting conjuncts between sentence pairs. With these in place, several sets of experiments were performed.
Approximate Sorting

We show that any comparison based, randomized algorithm to approximate any given ranking of n items within expected Spearman's footrule distance n2/ν(n) needs at least n (min{log ν(n), log n} – 6) comparisons in the worst case. This bound is tight up to a constant factor since there exists a deterministic algorithm that shows that 6n(log ν(n)+1) comparisons are always sufficient.
Dynamic Random Geometric Graphs

In this work we introduce Dynamic Random Geometric Graphs as a basic rough model for mobile wireless sensor networks, where communication distances are set to the known threshold for connectivity of static random geometric graphs. We provide precise asymptotic results for the expected length of the connectivity and disconnectivity periods of the network. We believe the formal tools developed in this work could be of use in future studies in more concrete settings. In addition, for static random geometric graphs at the threshold for connectivity, we provide asymptotic expressions on the probability of existence of components according to their sizes.
Optimal Multi-Paragraph Text Segmentation by Dynamic Programming

There exist several methods of calculating a similarity curve, or a sequence of similarity values, representing the lexical cohesion of successive text constituents, e.g., paragraphs. Methods for deciding the locations of fragment boundaries are, however, scarce. We propose a fragmentation method based on dynamic programming. The method is theoretically sound and guaranteed to provide an optimal splitting on the basis of a similarity curve, a preferred fragment length, and a cost function defined. The method is especially useful when control on fragment size is of importance.
Finding large and small dense subgraphs

We consider two optimization problems related to finding dense subgraphs. The densest at-least-k-subgraph problem (DalkS) is to find an induced subgraph of highest average degree among all subgraphs with at least k vertices, and the densest at-most-k-subgraph problem (DamkS) is defined similarly. These problems are related to the well-known densest k-subgraph problem (DkS), which is to find the densest subgraph on exactly k vertices. We show that DalkS can be approximated efficiently, while DamkS is nearly as hard to approximate as the densest k-subgraph problem.
Transport optimization on complex networks

We present a comparative study of the application of a recently introduced heuristic algorithm to the optimization of transport on three major types of complex networks. The algorithm balances network traffic iteratively by minimizing the maximum node betweenness with as little path lengthening as possible. We show that by using this optimal routing, a network can sustain significantly higher traffic without jamming than in the case of shortest path routing. A formula is proved and tested with numerical simulation that allows quick computation of the average number of hops along the path and of the average travel times once the betweennesses of the nodes are computed. Using this formula, we show that routing optimization preserves the small-world character exhibited by networks under shortest path routing, and that it significantly reduces the average travel time on congested networks with only a negligible increase in the average travel time at low loads. Finally, we study the correlation between the weights of the links in the case of optimal routing and the betweennesses of the nodes connected by them.
Reconstructing Websites for the Lazy Webmaster

Backup or preservation of websites is often not considered until after a catastrophic event has occurred. In the face of complete website loss, “lazy” webmasters or concerned third parties may be able to recover some of their website from the Internet Archive. Other pages may also be salvaged from commercial search engine caches. We introduce the concept of “lazy preservation”- digital preservation performed as a result of the normal operations of the Web infrastructure (search engines and caches). We present Warrick, a tool to automate the process of website reconstruction from the Internet Archive, Google, MSN and Yahoo. Using Warrick, we have reconstructed 24 websites of varying sizes and composition to demonstrate the feasibility and limitations of website reconstruction from the public Web infrastructure. To measure Warrick’s window of opportunity, we have profiled the time required for new Web resources to enter and leave search engine caches.
List decoding of noisy Reed-Muller-like codes

First- and second-order Reed-Muller (RM(1) and RM(2), respectively) codes are two fundamental error-correcting codes which arise in communication as well as in probabilistically-checkable proofs and learning. In this paper, we take the first steps toward extending the quick randomized decoding tools of RM(1) into the realm of quadratic binary and, equivalently, Z_4 codes. Our main algorithmic result is an extension of the RM(1) techniques from Goldreich-Levin and Kushilevitz-Mansour algorithms to the Hankel code, a code between RM(1) and RM(2). That is, given signal s of length N, we find a list that is a superset of all Hankel codewords phi with dot product to s at least (1/sqrt(k)) times the norm of s, in time polynomial in k and log(N). We also give a new and simple formulation of a known Kerdock code as a subcode of the Hankel code. As a corollary, we can list-decode Kerdock, too. Also, we get a quick algorithm for finding a sparse Kerdock approximation. That is, for k small compared with 1/sqrt{N} and for epsilon > 0, we find, in time polynomial in (k log(N)/epsilon), a k-Kerdock-term approximation s~ to s with Euclidean error at most the factor (1+epsilon+O(k^2/sqrt{N})) times that of the best such approximation.
Efficient Batch Update of Unique Identifiers in a Distributed Hash Table for Resources in a Mobile Host

Resources in a cloud can be identified using identifiers based on random numbers. When using a distributed hash table to resolve such identifiers to network locations, the straightforward approach is to store the network location directly in the hash table entry associated with an identifier. When a mobile host contains a large number of resources, this requires that all of the associated hash table entries must be updated when its network address changes. We propose an alternative approach where we store a host identifier in the entry associated with a resource identifier and the actual network address of the host in a separate host entry. This can drastically reduce the time required for updating the distributed hash table when a mobile host changes its network address. We also investigate under which circumstances our approach should or should not be used. We evaluate and confirm the usefulness of our approach with experiments run on top of OpenDHT.
Efficient Algorithms for Parsing the DOP Model

Excellent results have been reported for Data-Oriented Parsing (DOP) of natural language texts (Bod, 1993). Unfortunately, existing algorithms are both computationally intensive and difficult to implement. Previous algorithms are expensive due to two factors: the exponential number of rules that must be generated and the use of a Monte Carlo parsing algorithm. In this paper we solve the first problem by a novel reduction of the DOP model to a small, equivalent probabilistic context-free grammar. We solve the second problem by a novel deterministic parsing strategy that maximizes the expected number of correct constituents, rather than the probability of a correct parse tree. Using the optimizations, experiments yield a 97% crossing brackets rate and 88% zero crossing brackets rate. This differs significantly from the results reported by Bod, and is comparable to results from a duplication of Pereira and Schabes's (1992) experiment on the same data. We show that Bod's results are at least partially due to an extremely fortuitous choice of test data, and partially due to using cleaner data than other researchers.
Downscaling climate change of water availability, sediment yield and extreme events: Application to a Mediterranean climate basin

A robust hydrological impact assessment is indispensable for mitigation and adaptation planning. This study presents an integrated modelling methodology for evaluating climate change impacts on water availability, sediment yield and extreme events at the catchment scale. We propose the use of the spatial–temporal Neyman–Scott Rectangular Pulses (STNSRP) model—RainSim V3 and the rainfall conditioned daily weather generator—ICAAM‐WG, as well as the physically based spatially distributed hydrological model—SHETRAN. The change factor approach was applied for obtaining unbiased rainfall and temperature statistics. The ICAAM‐WG was developed based on the modified Climate Research Unit daily Weather Generator (CRU‐WG). The methodology is proposed to generate synthetic series of hourly precipitation, daily temperature and potential evapotranspiration, hourly runoff and hourly sediment discharge. We demonstrated a possible application in a 705‐km2 Mediterranean climate basin in southern Portugal. The case study showed the evaluation of future climate change impacts on annual and monthly water balance components and sediment yield, annual and seasonal flow duration curves, empirical extreme value distributions and the theoretical fits. It did not consider the possible uncertainty due to the limit of computational resources.