frequency term
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2020 ◽  
Vol 40 (05) ◽  
pp. 277-285
Author(s):  
Parthasarathi Mukhopadhyay ◽  
Anirban Dutta

It reports the development of an enhanced library OPAC prototype through integration of language analysis tool and book reader in the retrieval interface. Language analysis or text analytics is considered as one of the components of language documentation and when integrated with library OPAC can extend supports to analyse corpus of the retrieved document in terms of word/phrase frequency, term circus, term links, term context etc through visual representation in a single-window along with the other datasets generally expected in a typical library OPAC. The open source software based integration mechanism is tested with English and Bengali as mainstream languages and a Unicode-compliant Indian official tribal language Santali (Ol Chiki script) as minority language.


Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4669 ◽  
Author(s):  
Amit Kumer Podder ◽  
Md. Habibullah ◽  
Md. Tariquzzaman ◽  
Eklas Hossain ◽  
Sanjeevikumar Padmanaban

This paper presents a finite control-set model predictive control (FCS-MPC) based technique to reduce the switching loss and frequency of the on-grid PV inverter by incorporating a switching frequency term in the cost function of the model predictive control (MPC). In the proposed MPC, the control objectives (current and switching frequency) select an optimal switching state for the inverter by minimizing a predefined cost function. The two control objectives are combined with a weighting factor. A trade-off between the switching frequency (average) and total harmonic distortion (THD) of the current was utilized to determine the value of the weighting factor. The switching, conduction, and harmonic losses were determined at the selected value of the weighting factor for both the proposed and conventional FCS-MPC and compared. The system was simulated in MATLAB/Simulink, and a small-scale hardware prototype was built to realize the system and verify the proposal. Considering only 0.25% more current THD, the switching frequency and loss per phase were reduced by 20.62% and 19.78%, respectively. The instantaneous overall power loss was also reduced by 2% due to the addition of a switching frequency term in the cost function which ensures a satisfactory empirical result for an on-grid PV inverter.


Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4733
Author(s):  
Marcel Topler ◽  
Jožef Ritonja ◽  
Boštjan Polajžer

This paper discusses the imbalance netting process (INP) between control areas (CAs) that was developed due to the high costs of balancing energy. The main objective of INP is to net the demand for balancing energy between the participating CAs with opposite signs of interchange power variation. However, INP incorporates a frequency term; hence, it affects the frequency response of participating CAs inherently, which is not discussed in the literature. Therefore, the impacts of INP on the frequency quality and provision of load-frequency control (LFC) are shown thoroughly with dynamic simulations of a three-CA testing systems, in addition to an eigenvalue analysis of a two CA system. It is shown clearly herein that INP changes the eigenvalues of the system matrix, which results in decreased damping of the entire power system. Furthermore, the simulation results confirmed that INP reduces balancing energy, releases regulating reserve and reduces the unintended exchange of energy; thus, LFC performance indicators were improved. However, the impact of INP on frequency quality is not so explicit, since cases exist of frequency quality improvement and deterioration.


2019 ◽  
Vol 24 (3) ◽  
pp. 478-491 ◽  
Author(s):  
Barbara C Malt

Aims and objectives: This study contributes to understanding L2 word learning and why “semantic accent” persists. It examines the impact of L1–L2 semantic relations, input conditions, and L1–L2 dissimilarity on learning outcomes. Methodology: Mandarin-speaking learners of English labeled actions in 26 brief videos, typically called carrying or holding by native speakers. The labeling pattern is simpler in English than in Mandarin but requires a shift to different semantic dimensions. Further, hold is a higher frequency term than carry. The learners were resident in either China (N = 34) or the United States (N = 25), with somewhat higher proficiency in the US sample. Twenty native English speakers in the United States also responded. Data and analysis: Learner groups’ name choices were compared to each other and those of native speakers. Findings/conclusions: The dissimilarity between Mandarin and English did not block importing L1 meanings to L2, but progress was seen across sub-groups. Input variables did impact progress: immersion (mediated by proficiency) was better than classroom learning, and use of the higher frequency term was greater than of the lower. Notably, however, many learners narrowed to domain-relevant vocabulary without using the words in native-like ways despite the simplicity of the target L2 system. They appeared to update knowledge at the level of word form-to-domain mappings without updating word form-to-meaning associations. Originality: Semantic accent has been documented previously, but the L2 word learning trajectory and factors that contribute to semantic accent have not been well understood. This study advances that understanding. Significance/implications: Imported meanings are difficult to reshape even for dissimilar languages and even with immersion. Enhanced learning may require sensitizing learners to L2 semantic content via either explicit instruction or intensive exposure to discrepancies between L1 and L2 meanings.


Author(s):  
MANSUR ALP TOÇOĞLU ◽  
ADİL ALPKOÇAK

In this paper, we proposed a lexicon for emotion analysis in Turkish for six emotional categories happiness, fear, anger, sadness, disgust, and surprise. Besides, we also investigated the effects of a lemmatizer and a stemmer, two term-weighting schemes, four lexicon enrichment methods, and a term selection approach for lexicon construction. To do this, we generated Turkish emotion lexicon based on a dataset, TREMO, containing 25,989 documents. We then preprocessed the documents to obtain dictionary and stem forms of each term using a lemmatizer and a stemmer. Afterwards, we proposed two different weighting schemes where term frequency, term-class frequency and mutual information (MI) values for six emotion categories are taken into consideration. We then enriched the lexicon by using bigram and concept hierarchy methods, and performed term selection for efficiency issues. Then, we compared the performance of lexicon-based approach with machine learning based approach by using our proposed lexicon. The experiments showed that the use of the proposed lexicon efficiently produces comparable results in emotion analysis in Turkish text.


2018 ◽  
Vol 16 (02) ◽  
pp. 1850005 ◽  
Author(s):  
Óscar Álvarez ◽  
Juan Luis Fernández-Martínez ◽  
Celia Fernández-Brillet ◽  
Ana Cernea ◽  
Zulima Fernández-Muñiz ◽  
...  

We discuss applicability of principal component analysis (PCA) for protein tertiary structure prediction from amino acid sequence. The algorithm presented in this paper belongs to the category of protein refinement models and involves establishing a low-dimensional space where the sampling (and optimization) is carried out via particle swarm optimizer (PSO). The reduced space is found via PCA performed for a set of low-energy protein models previously found using different optimization techniques. A high frequency term is added into this expansion by projecting the best decoy into the PCA basis set and calculating the residual model. This term is aimed at providing high frequency details in the energy optimization. The goal of this research is to analyze how the dimensionality reduction affects the prediction capability of the PSO procedure. For that purpose, different proteins from the Critical Assessment of Techniques for Protein Structure Prediction experiments were modeled. In all the cases, both the energy of the best decoy and the distance to the native structure have decreased. Our analysis also shows how the predicted backbone structure of native conformation and of alternative low energy states varies with respect to the PCA dimensionality. Generally speaking, the reconstruction can be successfully achieved with 10 principal components and the high frequency term. We also provide a computational analysis of protein energy landscape for the inverse problem of reconstructing structure from the reduced number of principal components, showing that the dimensionality reduction alleviates the ill-posed character of this high-dimensional energy optimization problem. The procedure explained in this paper is very fast and allows testing different PCA expansions. Our results show that PSO improves the energy of the best decoy used in the PCA when the adequate number of PCA terms is considered.


2012 ◽  
Vol 7 (5) ◽  
pp. 266-271
Author(s):  
Yuhanis Yusof ◽  
Taha Alhersh ◽  
Massudi Mahmuddin ◽  
Aniza Mohamed Din

2010 ◽  
Vol 25 (11) ◽  
pp. 2293-2301 ◽  
Author(s):  
G. L. KLIMCHITSKAYA ◽  
B. GEYER ◽  
V. M. MOSTEPANENKO

We investigate the Casimir pressure between two parallel plates made of magnetic materials at nonzero temperature. It is shown that for real magnetodielectric materials only the magnetic properties of ferromagnets can influence the Casimir pressure. This influence is accomplished through the contribution of the zero-frequency term of the Lifshitz formula. The possibility of the Casimir repulsion through the vacuum gap is analyzed depending on the model used for the description of the dielectric properties of the metal plates.


2002 ◽  
Vol 17 (06n07) ◽  
pp. 751-760 ◽  
Author(s):  
G. L. KLIMCHITSKAYA

The situation with the temperature corrections to the Casimir force between real metals of finite conducitivity is reported. It is shown that the plasma dielectric function is well adapted to the Lifshitz formula and leads to reasonable results for real conductors. The Drude dielectric function which describes media with dissipation is found not to belong to the application range of the Lifshitz formula at nonzero temperature. For Drude metals the special modification of the zero-frequency term of this formula is suggested. The contradictory results on the subject in recent literature are analysed and explained.


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