90 research outputs found
Performance enhancement of active power filter in the presence of low order harmonics and distorted voltage
No full textDynamic characteristics of active power filter (APF) are dependent on APF control strategy performance. Synchronous reference frame (d-q) and instantaneous power theory (p-q) methods are the useful control strategies of APF. According to p-q and d-q methods, transient and steady state performance of the APF in these control methods is depends on the DC component separation speed and accuracy. The quick and accurate separation of DC component causes lower transient and THD in APF performance. So, in this paper, a discrete wavelet based low-pass filter (DWLPF) is proposed to improve the DC component separation speed and accuracy. To this end, three different methods are studied for discrete wavelet transform implementation and are compared with each other in transient response time, accuracy and computational cost. Afterward, the traditional low-pass filter (TLPF) in the p-q method is replaced by the new DWLPF to improve the DC component separation speed and accuracy and as a result enhancement of the transient and steady state performance of the three-phase APF. On other hand with fundamental extraction of point of common coupling (PCC) voltage using second order general integrator (SOGI), harmonics could be compensated by APF in a distorted voltage condition. The effectiveness of proposed method is examined by simulation and experimental results, which validates superiority of the proposed method
Algorithmic Approach for Learning a Comprehensive View of Online Users
No full textAbstractOnline users may use many different channels, devices and venues for any online user experience. To make all services such as web design, ads, web content, shopping, personalized for every user; we need to be able to recognize them regardless of device, channels and venues they are using. This, in turn, requires building up a comprehensive view of the user which includes all of their behavioral characteristics - that are spread all over these different venues. This would not be possible without having all behavioral related data of the user which requires the capacity of connecting the user all over the devices, and channels, so to have all of their behavior under a single view. This work is a major attempt in doing this using only behavioral data of users while protecting the user's privacy
Recommendation System Based on Complete Personalization
No full textAbstractCurrent recommender systems are very inefficient. There are many metrics that are used to measure the effectiveness of recommender systems. These metrics often include “conversion rate” and “click through rate”. Recently, these rates are in low single digit (less than 10%). In other words, for more than 90% of times, the model that the targeting system is based on, produces noise. The belief in this work is that the main problem leading to getting such unsatisfactory outcomes is the modeling problem. Much of the modeling problem could be represented and exemplified in treating users and items as member of clusters(segments). In this work, we consider full personalization of recommendation systems. We aim at personalization of users and contents simultaneously. Recommendations using baseline approach are inaccurate and targeting based on similarity-based recommendation (collaborative filtering) suffer from many disadvantages such as the neglect of interactive correlation. In this work, similarity based targeting has been combined with baseline approach and latent factor models and has been treated with adaptive regularization allowing complete personalization with respect to both users and items
Composiet multiferroïsche materialen gesynthetiseerd door ionenimplantatie in dunne films
No full textGrowth and characterization of BFO Ferro-electric thin films to be usedin spin transfer torque devices.status: Publishe
Morphology-induced spin frustration in granular BiFeO3 thin films: Origin of the magnetic vertical shift
No full text© 2018 Author(s). Pronounced room temperature vertical shifts in the magnetic hysteresis loops of granular, highly polycrystalline and ferromagnetic-like BiFeO3 thin films are observed upon field-cooling from a temperature above the Néel temperature of bulk BiFeO3. This is ascribed to the interplay between the preferential alignment, established by the field-cooling process, of the net magnetic moment, which arises from uncompensated antiferromagnetic spins, and the pinning of a fraction of these spins at the particle boundaries. Conversely, field-cooling of an epitaxially grown BiFeO3 film results in no vertical shift, confirming the effective role played by the particle boundaries (i.e., morphology) of the granular-like BiFeO3 films in the process of spin frustration.sponsorship: This work was financed by the Research Foundation-Flanders (FWO) and the KU Leuven Concerted Action (GOA/09/006 and GOA/14/007) programs. E.M. acknowledges the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No. 665919. M.L. and M.G. thank the Deutsche Forschungsgemeinschaft within SFB 762 "Functionality of Oxide Interfaces" for financial support. The authors thank the ESRF, Grenoble, France (Proposal No. HC-1586, BM20 beamline) for the allocation of SR beam time and C. Bahtz for the assistance during the experiments. The authors also extend their gratitude to Kerstin Brachwitz and Peter Schwinkendorf for the atomic force microscopy measurements. (Research Foundation-Flanders (FWO), KU Leuven Concerted Action|GOA/09/006, KU Leuven Concerted Action|GOA/14/007, European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant|665919, Deutsche Forschungsgemeinschaft within "Functionality of Oxide Interfaces"|SFB 762)status: Publishe
Carbon dioxide reforming of methane by pulsed glow discharge at atmospheric pressure: The effect of pulse compression
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The Flow Field Upstream Of A Horizontal Axis Wind Turbine
No full textA mathematical model is developed for a steady-state axi-symmetric upstream flow of a porous disc, in a uniform flow field . The special case of the upstream flow of a windmill, with and without a nacelle, is treated. First, the windmill is considered as a uniform distribution of sources and then as a linear distribution of sources. Solutions for the blade disc o f the wind field upstream are obtained in the form of stream1 ines and velocity vector components. Sample flow patterns upstream o f the blade disc o f the UMass 25 kW wind turbine are presented for several power levels. Documented computer programs applicable to any wind turbine are appended.9
Experimental and Numerical Study of Pile-to-Pile Interaction Factor in Sandy Soil
No full textAbstractIn structures to support large vertical and horizontal loads, piles are usually used in the form of closely spaced group. The piles in a group are not only affected by their individual loads transmitted from the pile cap, but also by additional loads transferred through the soil from the interference of neighboring piles. This group interaction influences the group stiffness, load-transfer mechanism and group settlement. In order to predict the response characteristics of pile groups, the interaction factors calculated using Mindlin's solution based on the theory of elasticity has been widely applied. The pile-to-pile interaction factor is defined as the ratio of displacements or rotations of an unloaded receiver pile to those of neighboring loaded source pile due to soil deformation. In this paper, a series of centrifuge model tests were carried out to examine the effect of soil relative density and pile spacing and pile tip condition on the interaction factor between two adjacent piles. Based on the results, soil relative density has a significant effect on the interaction between piles and thus it must be considered in the calculation of interaction factor. For this purpose, a correction to the Randolph and Wroth equation based on the test results was proposed in which the effect of soil relative density is contemplated. With an increase in the pile spacing, the value of interaction factor for all cases decreased. Compared to the effect of pile shaft, pile tip condition has a little effect on the interaction factor. The obtained results were also compared with those from a three-dimensional finite element analysis and a good agreement between the measured and the calculated results was observed
Overview of the Factors Music Making in Tamhidat by Ein al-Ghozat Hamedani
No full textAbstract
Figures of speech in addition to their aesthetic functions have different effects on words. Internal music is one of the effects of figures of speech which can play an important role in beautifying the word and its effect on the audience. The internal music comes with the use of verbal figures of speech. Figures that make words related by similarity or uniformity of vowels and consonants and create sensible alliteration. Categories of palilogy, alliteration, parallelism, pun and riming prose are among the figures of speech that play a major role in creating internal music of the poem. In this study, with a descriptive-analytical approach, we discuss the roll of music making factors in Tamhidat as an example of prose poem. The language of Ein ol-Ghozat in Tamhidat is preachy and didactical and in an addressing mode. Despite the intensity and sharpness of his speech, he speaks simple language with his audience. However, his words are in some cases melodious that influences audience and increases its penetration in the listener. The music of his words is natural so the listener can feel it with his spirit and takes its effect. Well syntagmatic arrangement of words is one of his language features that is based on music and phonemes' melody. This music gives words importance and predominance and makes Tamhida's prose a kind of prose poem. Applying some of the subtle and tiny musical elements such as parallelism (paronomasia /pun) makes the music of book more effective and catching. In other words, harmony of sounds and synchronization through which prose becomes rhythmic and melodious is one of the aesthetic aspects of the mystical prose of Ein ol-Ghozat that arises from his word's music and special intonation, so as human nature accepts it and enjoys reading. This word music is found in the form of alliteration, pun, repetition, and meter in important parts of his speech that sometimes becomes close to prosodic meter. In Ein ol-Ghozat's prose without feeling prosodic meter by listener, a wave of intonation and meter dominates resulted from alliteration and rhyme, and proximity of the number of syllables in every symmetry and perhaps likeness and nearness of the number of syllables in all or parts of the symmetries.
Repetition as a key element of the internal music is one of Ein ol-Ghozat's stylistic characteristic. Repetitions are seen in three forms in Ein ol-Ghozat languages. 1- Alliteration, this group consists of various kinds of pun, rhyme, repetition, etc. 2- Parallelism: Repetition of words or phrases. 3- Palilology: Repetition of word: This form is one of the most important and aesthetic repetition in Tamhidat that in addition to making prose integrated, is effective in conveying the concept and content of the message of Ein ol-Ghozat, as repetition of the words "Alas," " O’ Friend," and "O’ Dear" in several phrases has a great influence in stimulation of feeling and inculcation emotion in the reader.
Alliteration: One of the most important aspects of aesthetics in the mystical prose of Ein ol-Ghozat are sound harmony and alliteration that can be mainly found in pun/ paronomasia and riming. Usage of rhyme in all Tamhidat is not in the same level. Wherever discussion is didactic and reasoning, it is not generally riming, but where the subject is stories and anecdotes and analogies or becomes emotional, usually is riming. One manifestation of this figure is short sentences and aphorisms, whether the word is quotation of an old or an important person or whether the author expresses his own word.
Apart from these, Ein ol-Ghozat has worked other ways to enrich his word's music. The most important of these methods are:
Bringing words that at least their initials are co-voiced. Such as: "Ebtela" and "Emtehan"
Phonemes processing: a kind of internal music is repetition and sameness of consonants and vowels. This figure in some cases, with creating a specific internal music, highlights the phrases and helps to conveying the message and gives pleasure to the audience.
Bringing together words that make a pun is another species of alliteration in the language of Ein ol-Ghozat. This figure of speech is one of the best examples of creating and enhancing music in words or sentences.
Bringing together the co-meter terms is one of other species of alliteration in Tamhidat.
Repetition of words or phrases, are of those categories that is used in the mystical prose of Ein ol-Ghozat and is one of the stylistic features and music making elements of his Word. Repetition in Ein ol-Ghozat's language, sometimes have artistic and rhetorical aspects that helps his prose being rhythmic and is effective in conveying the meaning and intention of the speaker. Ein ol-Ghozat while repeats thoughts and beliefs of the mystics, repeats words and combinations in the various types, so that he not only raises the words' musical level and makes it melodious, but also increases the rhythmic role of his own speaking. Sometimes this repetition in the form of word or phrase in the end of sentence comes symmetrically, it functions like radif in hemistiches and if in the terms of syllables number be long, makes an intonation in the words too
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