nils-herrmann/clean_scirepeval huggingface dataset:
A new approach for web usage mining using case based reasoning
Year: 2020

In this study, we present a new approach for Web Usage Mining using Case Based Reasoning. Case Based Reasoning techniques are a knowledge based problem solving approach which is based on the reuse of previous work experience. Thus, the past experience can be deemed as an efficient guide for solving new problems. Web personalization systems which have the capability to adapt the next set of visited pages to individual users according to their interests and navigational behaviors have been proposed. The proposed architecture consists of a number of components, namely, basic log preprocessing, pattern discovery methods (By Case Based Reasoning and peer to peer similarity Clustering association rules mining methods) and recommendations. One of the issues considered in this study is that there are no recommendations to those who are different from the existing users in the log file. Also, it is one of the challenges facing the recommendations systems. To deal with this problem, Apriori algorithm was designed individually in order to be utilized in presenting recommendations; in other words, in cases where recommendations may be inadequate, using association rules can enhance the overall system performance recommendations. A new method used in this study is clustering algorithms for Nominal web data. Our evaluations show that the proposed method along with Standard case classified Log provides more effective recommendations for the users than the Logs with no case classification.
A Dual Band Polarization Reconfigurable Antenna for WLAN Systems
Venue: IEEE Transactions on Antennas and Propagation
Year: 2013

A new microstrip dual band polarization reconfigurable antenna is presented for wireless local area network (WLAN) systems operating at 2.4 and 5.8 GHz. The antenna consists of a square microstrip patch that is aperture coupled to a microstrip line located along the diagonal line of the patch. The dual band operation is realized by employing the TM10 and TM30 modes of the patch antenna. Four shorting posts are inserted into the patch to adjust the frequency ratio of the two modes. The center of each edge of the patch is connected to ground via a PIN diode for polarization switching. By switching between the different states of PIN diodes, the proposed antenna can radiate either horizontal, vertical, or 45deg linear polarization in the two frequency bands. Measured results on reflection coefficients and radiation patterns agree well with numerical simulations.
Insights into Galvanic Corrosion Behavior of Ti Cu Dissimilar Joint: Effect of Microstructure and Volta Potential
Venue: Materials
Year: 2018

The effect of microstructure on corrosion behavior of a solid state explosion welded Ti Cu bimetal is investigated by means of alternating current direct current (AC DC) electrochemical measurements, optical microscopy, scanning electron microscopy, and scanning Kelvin probe force microscopy (SKPFM) The results indicate that the titanium regions in the welding interface, local melted zone (LMZ) and LMZ Cu interface are potential sites for initiation of corrosion attacks. SKPFM mapping clearly shows that before exposure of the sample to a 3.5% NaCl corrosive solution and at the beginning of the exposure, the Cu side of the bimetal has a higher Volta potential in comparison to that of the Ti region, and thus acts as a cathode. Electrochemical measurements also confirm that titanium acts as an anode and copper as a cathode, in the first moments of immersion, in accordance with macroscopic observations and SKPFM results. However, by growing a passive layer of titanium oxide and titanium hydroxide on the Ti side after about 1 h exposure to the corrosive medium, the titanium side becomes nobler and the polarity arrangement in the galvanic couple reverses.
GloVeNoR: GloVe for Node Representations with Second Order Random Walks
Venue: 2020 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining (ASONAM)
Year: 2020

We study the community detection problem by embedding the nodes of a graph into a $n$ dimensional space such that similar nodes remain close in their representations. There are many state of the art methods, like node2vec and DeepWalk to compute node embeddings with the use of second order random walks. These techniques borrow methods like the Skip Gram model, used in the domain of Natural Language Processing (NLP) to compute word embeddings. This paper explores the idea of porting the GloVe (Global Vectors for Word Representation) model, a popular technique for word embeddings, to a new method called GloVeNoR, to compute node embeddings in a graph, and creating a corpus with the use of second order random walks. We evaluate the model's quality by comparing it against node2vec and DeepWalk on the problem of community detection on five different data sets. We observe that GloVeNoR discovers similar or better communities than the other existing models on all the datasets based on the modularity score.
Initial leakage current paths in the vertical type GaN on GaN Schottky barrier diodes
Year: 2017

Electrical characteristics of leakage current paths in vertical type n GaN Schottky barrier diodes (SBDs) on free standing GaN substrates are investigated by using photon emission microscopy (PEM) The PEM mapping shows that the initial failure of the SBD devices at low voltages is due to the leakage current paths from polygonal pits in the GaN epilayers. It is observed that these polygonal pits originate from carbon impurity accumulation to the dislocations with a screw type component by microstructure analysis. For the SBD without polygonal pits, no initial failure is observed and the first leakage appeals at the edge of electrodes as a result of electric field concentration. The mechanism of leakage at pits is explained in terms of trap assisted tunneling through fitting current voltage characteristics.
A comparison of the effectiveness of commercial and natural carbohydrate electrolyte drinks
Year: 2017

The aim of this study was to compare a natural carbohydrate electrolyte drink (ND) containing salt, banana, water, pineapple juice, lemon juice, and honey, with a commercially available sports drink (CD) in terms of their effectiveness at hydrating and their effects on the maintenance of blood glucose levels and changes in the level of biochemical parameters of the blood.  The study involved 11 rowers with an average age of 18.0 2.0 and an average of 3.8 1.4 years training. Their basic anthropometric and fitness parameters were measured. Then, in two sessions two weeks apart, the subjects performed 80 min of exercise on a rowing ergometer, during which they were administered one of the two tested drinks. Their body weight and blood biochemical parameters (glucose, lactate, HTC, urea, CK, WBC, LYM, MON, GRA, and FRAP) were measured both before and after the exercise.  During the exercise with CD, a significant decrease in body weight was reported, while body weight increased during the test with ND. Increases were seen in lactate, CK, WBC, LYM, MON, and GRA after consumption of both drinks. Hydration levels and the level of parameters associated with the maintenance of high physical fitness were comparable for both CD and ND. Despite this, it is necessary to further improve the ND formula.
Structured Compressed Sensing Matrices for Causality Detection
Venue: 2018 3rd IEEE International Conference on Recent Trends in Electronics, Information Communication Technology (RTEICT)
Year: 2018

Compressed sensing enables sparse signals to be stored and transmitted in a linearly compressed fashion and finds applications in magnetic resonance imaging, photography, transmission electron microscopy etc. Linear compression is achieved by matrix multiplication of the input sparse signals with a random sensing matrix (for e.g. independent Gaussian entries) and recovery is enabled by nonlinear optimization techniques. However, causal relationships between input signals are no longer preserved by such a compression. In this work, we design structured sensing matrices having Toeplitz and Circulant structure that preserve causality (as measured by Granger causality index) between sparse autoregressive coupled input signals in the compressed domain. A potential application of causality detection in the compressed domain is in neural signal processing.
Polycomb mediated methylation on Lys27 of histone H3 pre marks genes for de novo methylation in cancer
Venue: Nature Genetics
Year: 2007

Many genes associated with CpG islands undergo de novo methylation in cancer. Studies have suggested that the pattern of this modification may be partially determined by an instructive mechanism that recognizes specifically marked regions of the genome. Using chromatin immunoprecipitation analysis, here we show that genes methylated in cancer cells are specifically packaged with nucleosomes containing histone H3 trimethylated on Lys27. This chromatin mark is established on these unmethylated CpG island genes early in development and then maintained in differentiated cell types by the presence of an EZH2 containing Polycomb complex. In cancer cells, as opposed to normal cells, the presence of this complex brings about the recruitment of DNA methyl transferases, leading to de novo methylation. These results suggest that tumor specific targeting of de novo methylation is pre programmed by an established epigenetic system that normally has a role in marking embryonic genes for repression.
Improved UV B screening capacity does not prevent negative effects of ambient UV irradiance on PSII performance in High Arctic plants. Results from a six year UV exclusion study.
Venue: Journal of plant physiology
Year: 2010

Long term responses of ambient solar ultraviolet (UV) radiation were investigated on Salix arctica and Vaccinium uliginosum in a High Arctic heath ecosystem in Zackenberg, northeast Greenland. Over a period of six years, UV exclusion was conducted in the growing season by means of filters: 60% UV B reduction, 90% UV B+UV A reduction, UV transparent filter control, and an open control without filter. Plant responses were evaluated using specific leaf area, leaf content of UV B absorbing compounds and PSII performance parameters derived from chlorophyll a fluorescence induction curves. Based on the JIP test, we calculated the total performance index PI(total) which includes the integrating antennae, the PSII reaction center, intersystem electron transport and reduction of PSI end acceptors dependent parameters. In both species, UV exclusion significantly decreased the content of UV B absorbing compounds. Salix increased its specific leaf area, while Vaccinium decreased it. UV exclusion increased the PI(total) in both species during all six years of experimentation. This response was governed by a significantly decreased RC/ABS, a marginally non significant increased ET(o)/TR(o) and a significantly increased TR(o)/ABS=F(V)/F(M) and RE(o)/ET(o) These results demonstrate the current level of ambient UV B to decrease PSII performance significantly in these High Arctic plants. It appears that the two plant species both have improved their UV screening capacity, but through different strategies, although this did not sufficiently prevent negative effects of the ambient UV radiation. We argue the decreased PSII performance to be part of a response decreasing plant carbon uptake. We speculate the negative effects on PSII performance mediated by ambient UV irradiance to be present in years where warming induces early snowmelt, exposing the vegetation to high spring UV B, and to be present in the future to the degree the ozone layer is not fully recovered.
Identification of Best Practices to Ensure Market Access for the Smallholder Farmers in Kenya
Year: 2012

The greatest challenge to small holder farmers in Africa is lack of markets although new developments point to linking them to specific markets. Since linking farmers to markets in Kenyan agriculture is a relatively new phenomenon both at the level of government and the NGO/donor, it has not been established what works and what does not. Secondly, there is inadequate information and documentation on the nature of linkages of farmers to markets both in the public and private sector. The objective of the study was therefore to identify the different practices through which successful small holder farmers have gained access to remunerative markets. Based on a FAO nomenclature on the various approaches that small holder farmers' access markets globally, a market research was done in 2010 where a total sample of twenty farmers was selected from eight districts in Kenya. After further screening, only seven farmers meeting the FAO criteria were interviewed. The commodities that were considered were eggs, milk, avocado fruit, meat, horticultural produce, summer flowers, essential oils and bananas. Results showed that there were five best practices identified contributing to market access for small holder farmers: Production (adequate volume) Group's development dynamics (organized groups) Marketing (consistent supply) Marketing institutions (collaboration with marketing institutions) and Business development services (providing services to producers) It was concluded that implementing what is perceived as the best practices built self confidence, reduced perception of risk and through the market exposure, farmers acquired a set of new life skills: business, management, human relations and organization.
V TiO2 nanospindles with regulating tumor microenvironment performance for enhanced sonodynamic cancer therapy
Year: 2020

Sonodynamic therapy, with advantages in large tissue penetration depth and great controllability, is a promising type of non invasive cancer treatment method. Developing sonosensitizers with high reactive oxygen species (ROS) quantum yield and the ability to regulate tumor microenvironment to achieve enhanced performances in sonodynamic therapy would thus be rather attractive. Herein, vanadium (V) doped TiO2 (V TiO2) nanospindles with glutathione depleting properties are fabricated for enhanced sonodynamic cancer therapy. Due to doping of the V element, the bandgap of V TiO2 nanospindles is reduced, increasing the efficiency of ultrasound triggered ROS production compared to that of pure TiO2 nanoparticles. More interestingly, the doping of V also makes V TiO2 nanospindles an effective Fenton like agent, which can catalyze the generation of highly toxic hydroxyl radicals *OH) from endogenous H2O2 in the tumor, thus enabling cancer killing through chemodynamic therapy. In addition, the V doping also endows V TiO2 nanospindles with the function of glutathione depletion, further amplifying the oxidative stress generated by chemodynamic sonodynamic therapy. In vitro cell experiments and in vivo animal experiments demonstrate that V TiO2 nanospindles can effectively kill cancer by the combined chemodynamic sonodynamic therapy, significantly improving the tumor treatment outcomes. Importantly, V TiO2 with the ultrasmall spindle morphology can be quickly excreted from the body, without causing any long term toxicity. This work illustrates that doping TiO2 with other special elements is a meaningful strategy to fabricate nanostructures with interesting functions useful in biomedicine.
Tax compliance: an administrative burden for small business enterprises (SME'S)
Year: 2016

As is the case in many economies, tax laws are sometimes very complicated and difficult for SME's to understand and to implement. Tax laws change every year, impacting on the business, its operations and its profitability. It is also a fact that the more a government overspends, misappropriate funds and overall lack fiscal control, the more they will try and recover these "losses" from the taxpayers including SME's. The main purpose of the study is to investigate whether small business enterprises are burdened by the administrative processes required in South Africa to comply to with the tax regulations of the country. The South African government has strict policies and procedures in place that all businesses should adhere to. However, the key challenge that many SME's still face is that of red tape and burdensome regulatory processes and procedures. In an attempt to establish the main objective of the study, a quantitative approach research approach was employed and a significant amount of small businesses were surveyed. From the findings it is clear that the respondents of the survey agree that the tax services registration documentation and process should be made easier. The submission of the registration documents, once understood and completed, is not a big problem for the respondents. The cost of registration does not seem to be a major burden to the SME's.
Aram Saroyan and the One Word Poem
Year: 2019

LE LIONNAIS, two of France's most significant postwar literary experimentalists, wondered to one another "how few words can make a poem?"1 According to LE LIONNAIS, this question would preoccupy the two until QUENEAU's death fifteen years later. Even in 1976, they doubted that a poem could be constructed from fewer than several words. Perhaps because their backgrounds were not primarily in experimental poetry or postwar art LE LIONNAIS was a mathematician and QUENEAU primarily a novelist and editor) the two oddly overlooked concrete poetry. The two also seemed unaware of the work of ARAM SAROYAN, whose mid 1960s poems explored and broke the limits proposed by QUENEAU and LE LIONNAIS. Though the Oulipo's founders may have been underinformed about concrete poetry (which did not have as strong a presence in France as it did in Latin America, North America, or German speaking countries) their skepticism is telling: setting aside concrete poetry in the 1950s, for the most part it was not until the 1960s with the coeval emergence of pop art, minimalism,
Learning Negative Mixture Models by Tensor Decompositions
Venue: ArXiv
Year: 2014

This work considers the problem of estimating the parameters of negative mixture models, i.e. mixture models that possibly involve negative weights. The contributions of this paper are as follows. (i) We show that every rational probability distributions on strings, a representation which occurs naturally in spectral learning, can be computed by a negative mixture of at most two probabilistic automata (or HMMs) (ii) We propose a method to estimate the parameters of negative mixture models having a specific tensor structure in their low order observable moments. Building upon a recent paper on tensor decompositions for learning latent variable models, we extend this work to the broader setting of tensors having a symmetric decomposition with positive and negative weights. We introduce a generalization of the tensor power method for complex valued tensors, and establish theoretical convergence guarantees. (iii) We show how our approach applies to negative Gaussian mixture models, for which we provide some experiments.
Rheology of Cement Pastes with Siliceous Fly Ash and the CSH Nano Admixture
Venue: Materials
Year: 2021

The use of fly ash in cement composites adversely affects its mechanical properties during the first days of mixture curing. Modern technology, in the form of an admixture containing the hydrated calcium silicates, allows to accelerate the hardening and binding process of concrete. In this paper, studies on the influence of the admixture on properties of concretes with the ordinary Portland cements (OPC) containing the addition of siliceous fly ash (FA) have been carried out. As part of the experimental research, the authors conducted a series of studies for cement pastes modified with the addition of FA and the CSH nano admixture (NA) In order to compare the mixtures, the following tests of cement pastes were carried out: the compressive and flexural strength, heat of hydration, SEM and rheological shrinkage. The mechanical parameters were tested after 4, 8, 12 and 24 h. The hydration heat test and microstructure analysis were carried out during the first 24 h of the concrete curing. All tests were carried out on the standard samples. On the basis of the heat of hydration test, much higher hydration heat was found in mixtures modified with the NA. During the shrinkage test, a positive effect of the NA was observed the shrinkage during the first 28 days of mixture curing was lower than in the reference samples. The application of the CSH nano admixture to cement pastes with the addition of FA has brought positive effects. Apart from a significant increase in strength in the first 24 h of mixture curing, a reduction in the rheological shrinkage was observed. The admixture can be successfully used in the ash concretes, in which a higher early strength is required.
Effect of nanobubbles for improvement of water quality in freshwater: Flotation model simulation
Year: 2020

Recently, nanobubbles (NBs) in flotation have been discussed as a highly promising technique for separation or remediation of water contaminants in the environmental field. This study performed model simulations using a flotation model (FM) with NBs and very highly hydrophobic small particles, such as sediments of freshwater containing inorganic particles (clay and silt) and plastic debris. This study examined and confirmed that the effect of NBs for remediation of particles depends on the size and number of bubbles, size and density of aggregates, time of aggregate formation, and so on. This study also confirmed the NBs' features, such as the adjustment of their surface charge in electrolyte solutions as well as their affinity for hydrophobic surfaces leading to their stability. The features affect the attachment efficiency, which is estimated by calculating the surface interaction forces of hydrodynamics and surface chemistry. The aggregates formed by the attached NBs obtained very high formation efficiency (X) due to their very high attachment efficiency but very low separation efficiency (Y) due to their very slow rising velocity. In conclusion, the NBs may deteriorate the water quality instead of improving it because the aggregates formed by the NBs stay in the suspension for a long stagnation time. Therefore, further research is required to discover a more reasonable method for applying NBs with MBs in the field of freshwater treatment that causes a minimal adverse effect on the ecosystem and helps in optimal removal efficiency of the hydrophobic fine particles.