Miracle-dz/UniFAR-FTUs huggingface dataset:
Virtual inertia control of DFIG-based wind turbines for dynamic grid frequency support

This paper investigates virtual inertia control of doubly fed induction generator (DFIG)-based wind turbines to provide dynamic frequency support in the event of abrupt power change. The model and control scheme of the DFIG is analysed. The relationships among the virtual inertia, the rotor speed and the network frequency variation are then investigated. The "hidden" kinetic energy that can be released to contribute to the grid inertia by means of shifting the operating point from the maximum power tracking curve to a virtual inertia control curve is investigated. The virtual inertia control strategy based on shifting power tracking curves of the DFIG is proposed and the calculation method for determining these virtual inertia control curves is presented. A three-machine system with 20 percent of wind penetration is used to validate the proposed control strategy. Simulation results show that by the proposed control strategy, DFIG based wind farms have the capability of providing dynamic frequency support to frequency deviation, and thus improving the dynamic frequency performance of the grid with high wind power penetration. (6 pages)
Application of Central Composite Design and Artificial Neural Network for the Optimization of Fermentation Conditions for Lipase Production by Rhizopus arrhizus MTCC 2233

The response surface optimization strategy was used to enhance the lipase production by Rhizopus arrhizus MTCC 2233 in submerged fermentation. Various vegetable oils were experimented as an inducer using the optimized medium to study the influence on lipase production, and corn oil was found to be the best inducer for lipase production by Rhizopus arrhizus. The optimization of fermentation conditions, temperature, initial pH and agitation speed was carried out using corn oil as the inducer. Statistical analysis of the experimental data showed that the temperature, agitation speed, quadratic effects of temperature, initial pH and agitation speed and interactive effects of temperature and agitation speed are significant parameters that affect lipase production. The optimum fermentation conditions were achieved at 32°C; pH 6.0 and agitation speed of 107 rpm with the maximum lipase activity of 4.32 U/mL. Artificial neural network model was used to predict the lipase activity and cell mass production under various fermentation conditions. Unstructured kinetic models, Logistic model, Luedeking-Piret model and modified Luedeking-Piret model were used to describe the cell biomass, lipase production and glucose utilization kinetics respectively.
Upscaling Strategies of Porosity-Permeability Correlations in Reacting Environments from Pore-Scale Simulations

In geochemically reacting environments, the mineral dissolution and precipitation alters the structural and transport properties of the media of interest. The chemical and structural heterogeneities of the porous media affect the temporal evolution of the permeability with respect to porosity. Such correlations follow a nonlinear trend, which is difficult to estimate a priori and without knowledge of the microstructure itself, especially under the presence of strong chemical gradients. Macroscopic field-scale codes require such an input, and in the absence of exact descriptions, simplified correlations are used. After highlighting the diversity of microstructural evolution paths, due to dissolution, we discuss possible upscaling strategies.
Shade-ring corrections for pyranometer measurements of diffuse solar radiation from cloudless skies

SUMMARY When a shade ring is used to shield a pyranometer from direct solar radiation, a correction to the measured diffuse radiation is necessary to account for diffuse radiation intercepted by the ring. A general analysis is developed to relate shade-ring corrections to the radiance distribution of diffuse radiation. The corrections are split into two components: a geometric component based on an isotropic sky and varying with shade-ring dimensions; and an anisotropy component, relatively independent of ring dimensions. Shade-ring corrections are calculated using mean distributions of the radiance of cloudless skies. Tables and figures are given for calculating these corrections as functions of latitude, ring dimensions and time of year. Comparisons with published measurements at a variety of sites reveal generally good agreement with calculations. Some of the discrepancies may be due to differences in aerosol scattering.
Evaluating Hydrological Model Performance using Information Theory-based Metrics

Abstract. The accuracy-based model performance metrics not necessarily reflect the qualitative correspondence between simulated and measured streamflow time series. The objective of this work was to use the information theory-based metrics to see whether they can be used as complementary tool for hydrologic model evaluation and selection. We simulated 10-year streamflow time series in five watersheds located in Texas, North Carolina, Mississippi, and West Virginia. Eight model of different complexity were applied. The information theory based metrics were obtained after representing the time series as strings of symbols where different symbols corresponded to different quantiles of the probability distribution of streamflow. The symbol alphabet was used. Three metrics were computed for those strings – mean information gain that measures the randomness of the signal, effective measure complexity that characterizes predictability and fluctuation complexity that characterizes the presence of a pattern in the signal. The observed streamflow time series has smaller information content and larger complexity metrics than the precipitation time series. Watersheds served as information filters and and streamflow time series were less random and more complex than the ones of precipitation. This is reflected by the fact that the watershed acts as the information filter in the hydrologic conversion process from precipitation to streamflow. The Nash Sutcliffe efficiency metric increased as the complexity of models increased, but in many cases several model had this efficiency values not statistically significant from each other. In such cases, ranking models by the closeness of the information theory based parameters in simulated and measured streamflow time series can provide an additional criterion for the evaluation of hydrologic model performance.
Stochastic Interest Rate Approach of Pricing Participating Life Insurance Policies with Embedded Surrender Option

Life insurance contracts are priced and analysed using techniques from actuarial and modern financial mathematics, which requires that, the conditions for the risk-neutral valuation are fulfilled and that, a specified underlying security and an equivalent martingale measure must exist. This paper analysed life insurance endowment policy, paid by sequence of periodical premiums in Ghana with a guaranteed minimum return to the policyholder. Again, this paper presents two premium determination schemes for the insurance policy, the constant premium case and the periodical adjustment case in which both the benefit and the periodical premiums are annually adjusted in relation to the performance of a reference portfolio. It was realized that, with rising guaranteed interest rate, the rate of return on the reference portfolio, the premiums of the whole contract decreased both in the constant and the periodical adjustment cases whiles an increase in the participating coefficient and age of the insured led to an increase in the whole premium both in the constant and periodical adjustment cases. Also, it was revealed that, the premium of the non-surrendered bonus option is smaller in the constant premium case than in the periodical adjustment case and the premium of the bonus option in the surrendered participating policy looks cheap in the constant premium case than in the periodical adjustment case. Thus, it’s about 1.03% and 6.95% respectively of the total premium for the constant and for the periodical adjustment cases.
A comparative analysis of artificial neural network technologies in intrusion detection systems

Intrusion Detection is a major focus of research in the security of computer systems and networks. This paper presents an analysis of Artificial Neural Networks (ANN) being used in the development of effective Intrusion Detection Systems for computer systems and computer networks. The ANNs technologies, which are discussed, are designed to detect instances of the access of computer systems by unauthorized individuals and the misuse of system resources. A review of the foundations of Intrusion Detection Systems and other ANNs, which are the focus of current development efforts, is presented. The results of comparative analysis of different ANNs in Intrusion Detection are discussed. Finally, a discussion of the future ANN technologies, which guarantee to enhance the ability of computer systems to detect intrusions is provided.
Cooperation between Local Authorities and Economic Entities in Polish Economic Zones – Evidence from Lower Silesia in Poland

DOI: 10.14254/2071789X.2018/11-2/6 ABSTRACT. The article presents the phenomenon of special economic zones (SEZs) in Poland through characteristics of its legal, organizational and economic aspects. The detailed study of benefits and expectations from local authorities and managing authority of SEZs in Lower Silesia has been presented. The aim of this paper is to explain the phenomenon and the importance of cooperation between the enterprises located in special economic zones (SEZs) and also, between enterprises and local authorities. The authors hypothesize that participation in SEZs activities results in establishing cooperation among other entities within and beyond SEZs. For this paper, we designed and conducted a survey among economic entities seated in SEZs of Lower Silesia region. A simple random sampling approach was used with a representative number of economic entities’ subpopulations proportionally reflecting the size of enterprises (small, medium, large) in the studied population. The interview questionnaire comprises a set of 24 questions referring to various aspects in the functioning of enterprises in SEZs. The conducted research have found that although research entities indicated legal obstacles, confusing regulations, shortage of personnel, or limited space for enterprise development in SEZs in Lower Silesia they qualified relationships with local authorities as very favourable and rather favourable. Despite the identified unfavourable conditions for conducting business the researched entities invested in new technologies, services and further expansion during their activity in SEZs. The researched entities also recognized the crucial role of the authority formally managing SEZs and their satisfaction resulting from relationships with local authorities.
Is experience in the public sector associated with Big Five personality aspects

espanolEl concepto de ajuste persona-organizacion sugiere que empleados con experiencia en el sector publico difieren en aspectos de la personalidad de aquellos con escasa o ninguna experiencia. Cuando se puso a prueba esta hipotesis entre 711 participantes en cursos de extension para ejecutivos de una universidad peruana, se observo diferencias significativas en las Escalas de Aspectos de los Cinco Grandes entre hombres y mujeres y segun la edad, pero la experiencia en el sector publico solo predijo mayor Apertura. Las mujeres presentaron mayor Apertura que los hombres y una interaccion significativa de genero x tiempo en el sector publico revelo que la prediccion de Apertura desde la experiencia en el sector publico era mas pronunciada entre los hombres. Los hallazgos sugieren que, en la poblacion estudiada, pocas diferencias de personalidad son atribuibles a la experiencia en el sector publico. Se necesita estudios que evaluen la validez externa de los hallazgos. EnglishThe hypothesis that employees with experience in the public sector differ in personality aspects from those with less or no experience, suggested by the concept of person-organization fit, was tested among 711 participants in executive extension courses of a Peruvian university who filled-in the Big Five Aspect Scales. Whereas significant differences in various personality aspects were observed along age and between males and females, public sector experience only predicted greater Openness. Women outperformed men in Openness and a significant gender x time in public sector interaction revealed that prediction of Openness from the public-sector experience was more pronounced among men. The findings suggest that, in the population studied, little personality differences are attributable to experience in the public sector. Studies are needed to evaluate the external validity of the findings.
Optimal disassembly of complex products

This paper presents a method for determining the optimum disassembly sequence for selective disassembly of discarded complex products. This methodology has been developed within the framework of the increasing need for formulation of a theory on selective disassembly and the various purposes of it. The objective of the optimization is maximizing the economic performance of the disassembly process within given technical and environmental constraints. It is demonstrated that the method, that is based on graphs, can be used to generate optimum sequences according to various objectives in a straightforward way. Also a ranking of the most favourable alternative sequence is possible. This is important to the inclusion of other criteria in the model and in adaptation of the disassembly system to fluctuating parameters like material yields and constraints. Contrary to earlier work on generation of disassembly sequences, in selective disassembly all possible incomplete disassembly sequences are included. This cons.
PROTOTYPE COUPLING OF THE CFD SOFTWARE ANSYS CFX WITH THE 3D NEUTRON KINETIC CORE MODEL DYN3D

The CFD code ANSYS CFX has been coupled with the neutron-kinetic core model DYN3D. ANSYS CFX calculates the fluid dynamics and related transport phenomena in the reactor’s coolant and provides the corresponding data to DYN3D. In the fluid flow simulation of the coolant, the core itself is modeled by the porous body approach. DYN3D calculates the neutron kinetics and the fuel behavior including the heat transfer to the coolant. The physical data interface between the codes is the volumetric heat release rate into the coolant. In the prototype that is currently available, the coupling is restricted to single-phase flow problems. In the time domain an explicit coupling of the codes has been implemented so far. Steady-state and transient verification calculations for a small-size test problem confirm the correctness of the implementation of the prototype coupling. This test problem was a mini-core consisting of nine real-size fuel assemblies. Comparison was performed with the DYN3D standalone code. In the steady state, the effective multiplication factor obtained by the ANSYS CFX/DYN3D codes shows a deviation of 9.8 pcm from the DYN3D stand-alone solution. This difference can be attributed to the use of different water property packages in the two codes. The transient test case simulated the withdrawal of the control rod from the central fuel assembly at hot zero power. Power increase during the introduction of positive reactivity and power reduction due to fuel temperature increase are calculated in the same manner by the coupled and the stand-alone codes. The maximum values reached during the power rise differ by about 1 MW at a power level of 50 MW. Beside the different water property packages, these differences are caused by the use of different flow solvers.
Nanomechanics of nonideal single- and double-walled carbon nanotubes

The buckling characteristics of nonideal single- and double-walled carbon nanotubes were studied in this work via molecular dynamics simulation method. An imperfectly straight nonideal single-walled carbon nanotube (SWCNT) with a bent along the tube axis was used to form an array which is subjected to compression. The change in orientation of bends will result in a variation of nonbonded interactions in an SWCNT array system. We find that these variations in the nonbonded interactions strongly affect the buckling resistance of the SWCNT array. Similarly, a nonideal double-walled carbon nanotube (DWCNT) is constructed by varying the interlayer distance by introducing a center offset on the inner core SWCNT. The inclusion of offset along the tube axis in such nonideal DWCNT can enhance or deteriorate the mechanical qualities of the DWCNT under compression. Our numerical studies on nonideal CNT systems suggest a possibility of designing high-performing CNTs for applications involving fiber reinforcements.
A pilot genetic study reveals the absence of spatial genetic structure in Norway lobster (Nephrops norvegicus) on fishing grounds in Icelandic waters

Pampoulie, C. , Skirnisdottir, S. , Hauksdottir, S. , Olafsson, K. , Eiriksson, H. , Chosson, V. , Hreggvidsson, G. O. , Gunnarsson, G. H. , and Hjorleifsdottir, S. 2011. A pilot genetic study reveals the absence of spatial genetic structure in Norway lobster (Nephrops norvegicus) on fishing grounds in Icelandic waters. – ICES Journal of Marine Science, 68: 20–25.Stock structure of Norway lobster off southern Iceland was investigated using 12 microsatellite loci. No genetic method detected significant genetic differentiation among the locations sampled, even among Icelandic samples and an out-group from Scotland. Testing the power of resolution of microsatellite loci, the loci and sample sizes used were sufficient to detect significant genetic differentiation with confidence. The lack of genetic structure is discussed in terms of the level of gene flow, recent isolation of populations, and the statistical power of the experimental design.
CDK prevents Mcm 2 – 7 helicase loading by inhibiting Cdt 1 interaction with Orc 6

In Saccharomyces cerevisiae cells, B-type cyclin-dependent kinases (CDKs) target two origin recognition complex (ORC) subunits, Orc2 and Orc6, to inhibit helicase loading. We show that helicase loading by ORC is inhibited by two distinct CDK-dependent mechanisms. Independent of phosphorylation, binding of CDK to an ‘‘RXL’’ cyclinbinding motif in Orc6 sterically reduces the initial recruitment of the Cdt1/Mcm2–7 complex to ORC. CDK phosphorylation of Orc2 and Orc6 inhibits the same step in helicase loading. This phosphorylation of Orc6 is stimulated by the RXL motif and mediates the bulk of the phosphorylation-dependent inhibition of helicase loading. Direct binding experiments show that CDK phosphorylation specifically blocks one of the two Cdt1binding sites on Orc6. Consistent with the inactivation of one Cdt1-binding site preventing helicase loading, CDK phosphorylation of ORC causes a twofold reduction of initial Cdt1/Mcm2–7 recruitment but results in nearly complete inhibition of Mcm2–7 loading. Intriguingly, in addition to being a target of both CDK inhibitory mechanisms, the Orc6 RXL/cyclin-binding motif plays a positive role in the initial recruitment of Cdt1/Mcm2–7 to the origin, suggesting that this motif is critical for the switch between active and inhibited ORC function at the G1-to-S-phase transition.
Λ = 0 Cosmology of a Brane-like Universe

We examine the possibility that Friedman-Robertson-Walker evolution is governed by an effective (rather then by the actual) energy density. A concrete example is provided by Λ = 0 ReggeTeitelboim cosmology, where critical cosmology only requires subcritical matter density (Ωm < 1), and the age of a flat matter dominated Universe gets enhanced by a factor of 9 8 . Dual to the mature dilute Universe is the embryo Universe, the evolution of both is governed by Peff = − 1 9ρeff .
Modeling the effects of quality in a transformative health service

Understanding the effects of service quality on economic (i.e., continuance intentions) and social (i.e., quality of life) outcomes is critical to extend the focus of transformative service research. This study specifies mHealth as a transformative service and models the impact of its overall quality on satisfaction, continuance intentions and quality of life. Based on cognition affective conation chain, the conceptual model explicitly identifies convenience, confidence, cooperation, care and concern as the primary dimensions of mHealth service quality. The study validates the higher-order quality model and its association with subsequent latent variables using PLS path modeling. The findings confirm that quality has a significant impact on satisfaction, continuance and QOL in the context of a transformative mHealth service.
Feed Passage Rate in Broiler Chickens Fed on Rye-Based Diet Supplemented with Essential Oil Components

The present study was conducted to monitor feed passage rate in broiler chickens fed on either corn-or rye-based diet, or the rye-based diet supplemented with essential oil components. A total of 80 oneday old female broiler chickens were randomly allotted into 5 dietary treatments. There were five experimental diets; corn-based diet, rye-based diet, rye+100 ppm thymol, rye+100 ppm cinnamaldehyde and rye+100 ppm CRINA Poultry. At day 7, rye-based diet-fed chickens exhibited stunted growth and increased vent score ® compared with the corn-based diet-fed counterparts. When essential oil components added into the ryebased diet, no clear reduction in stunted growth and vent score was observed in all treated groups. The feed passage rate was monitored at 28-days of age. It was found that time required for 50% of marker excretion was not significantly different between experimental groups including the two control groups i.e., corn versus rye groups. Similarly, excretion curve pattern was almost identical between experimental groups. In summary, broiler chickens fed on rye-versus corn-diet showed identical feed passage rate at 4 weeks of age without affecting body weight and feed intake. In addition, supplementation of essential oil components into the rye-based diet did not affect feed passage rate.
Audit Quality in Practice: A Critical Analysis of the Financial Reporting Council (FRC) Discussion Paper

The efforts by the Financial Reporting Council (FRC) in the United Kingdom (UK) to stimulate audit firms to improve audit quality manifest in its Discussion Paper: Promoting Audit Quality warrant further analysis. The discussion paper identified factors such as audit firm culture, the quality of people, the effectiveness of audit process, and outside factors such as management and audit committee (AC) which can affect level of audit quality in practice. Reporting upon the analysis of responses to the discussion paper, the objective of this study is to analyze views from the respondents about various issues related to audit quality. This study composes of how subject of audit quality is seen in practice, which contributes to our understanding of conditions, events, or processes that can affect audit quality in practice.
Finding a suitable benchmark for commercial bank branches using DEA

This paper proposes a suitable benchmark for inefficient commercial bank branches by using Data Envelopment Analysis (DEA). In order to render an inefficient bank branch efficient, it is necessary to decrease inputs and increase outputs. As there are priorities for decreasing some certain inputs and increasing some certain outputs over other inputs and outputs, respectively, it is necessary to consider and incorporate the managers’ view regarding the priorities in the models which are applied. So, in this paper, using the enhanced Russell model for an inefficient bank branch, we propose the decrease in inputs and the increase in outputs, taking the managers’ priorities into account. Finally, in a numerical example, we apply the proposed procedure to the authentic information from 30 commercial bank branches, to show the application of the procedure.