Miracle-dz/UniFAR-FTUs huggingface dataset:
Parallel operation of one-cycle controlled three-phase PFC rectifiers

Parallel operation of three-phase power factor corrected (PFC) rectifiers extends the power range to a much higher level and allows modular design. However, circulating current among the modules could be a potential problem. This paper studies the circulating current phenomenon within two paralleled rectifiers and proposes a new current sharing method based on one-cycle control with vector operation and bipolar operation. With some minor addition to the original one-cycle control circuit and a simple add-on communication path among the individual modules, the circulating current is eliminated, while the OCC advantages, such as constant switching frequency, no multipliers, and simple circuitry, are preserved. Two one-cycle controlled rectifiers of 2.5 kW each were built and tied together using the proposed parallel operation method. Experiments have shown the simplicity and the effectiveness of this method.
Installation, startup and performance of a static var compensator for an electric arc furnace upgrade

This steel maker upgraded the Electric Arc Furnace (EAF) Melt Shop to increase production and improve metallurgical quality of their product. The increased electrical load and harmonic generation for the new furnace operation necessitated the installation of a 80 MVAR static var compensator (SVC) to meet utility interconnect requirements. This paper is a follow-up and companion to [1] that documented comprehensive analysis to specify the SVC. This paper describes the sequence of events during the installation, commissioning and operation of the SVC. It will assess the performance of the SVC compared to the electrical requirements of the utility for voltage regulation, flicker, harmonics and power factor. Power quality measurements during EAF operation without the SVC established a baseline to from which to show improvements provided by the SVC as well as compliance with the utility limits. Additionally, events encountered during the commissioning are shared as lessons learned.
Indigenous entrepreneurship and indigenous employment in Australia

This article investigates the theoretical underpinnings of Indigenous entrepreneurship and the disproportionate capacity for Indigenous enterprises to generate jobs for Indigenous peoples in Australia. It builds on the existing scholarship on Indigenous entrepreneurship - which has mostly focused on individual Indigenous entrepreneurs and the extent to which they generate employment and other benefits for the local community - to also examine the opportunities and constraints for Indigenous enterprises and employment within Indigenous economies, with reference to New South Wales. In this, we define Indigenous economies as referring less to individual Indigenous entrepreneurs or businesses and more to Indigenous people as a polity, for example as First Nations peoples who engage in the economy through their land estate. We are here exploring a distinction between Indigenous entrepreneurialism and the entrepreneurialism possible as First Nations people and thus an Indigenous economy.
High spatial resolution Hall nano-sensors by tuned direct-write Co/C-FEBID

Gas assisted focused electron beam induced deposition is a direct write technique that allows for the deposition of nanoscale structures inside standard scanning electron microscopes. Here we show that the composition of the nano-deposits can depend on their size, which can be used as an additional parameter, besides the control of the beam dwell time, in order to tune the metal/matrix ratio and to obtain new nanoscale materials with tailored properties. By optimizing the Cobalt/Carbon ratio and the size of the active area, it was possible to obtain superparamagnetic Hall sensors with outstanding magnetic spatial resolution. These sensors have been successfully used for detecting single paramagnetic micro-beads commonly used as labels in biological and medical research.
Design of a forward looking synthetic aperture radar for an autonomous cryobot for subsurface exploration of europa

In this paper a forward looking (end fire) synthetic aperture radar (SAR) system is described for the Very deep Autonomous Laser-powered Kilowatt-class Yo-yoing Robotic Ice explorer (VALKYRIE) project. Design and analysis of novel conformal log periodic antennas for the radar and the forward looking SAR ambuguity function is presented. Fabrication and laboratory characterization of the antennas system design and in situ testing of the SAR system are discussed in detail.
An investigation into the technical impacts of microgeneration on UK-type LV distribution networks

In a bid to meet the UK renewable energy targets, and to reduce GHG emissions in accordance with the Kyoto Protocol, the UK government is encouraging small scale developers through different incentive schemes. So far, the UK renewable energy generation has seen a steady growth but there are concerns about the impacts of these on the power system network. Sequel to this, the UK research councils have invested in microgeneration specific researches, one of which is the impact of significant microgeneration penetration on the LV/MV/HV network to 2050 [1]. This paper investigates the technical impacts of microgeneration on the UK low voltage distribution networks, using the Solar PV as a case study. Technical impacts considered include voltage rise, voltage unbalance, reversed power flow, transformer and cable loading, system losses and harmonics. The networks were modeled using OpenDSS and simulations performed using MATLAB via the OpenDSS COM interface. The analysis of the results obtained show that the aforementioned impacts increased with high solar PV penetration, but within acceptable limits. However, the variations of solar PV penetration beyond the acceptable limits of the network were illustrated.
General Correlations of Iso-octane Turbulent Burning Velocities Relevant to Spark Ignition Engines

A better understanding of turbulent premixed flame propagation is the key for improving the efficiency of fuel consumption and reducing the emissions of spark ignition gasoline engines. In this study, we measure turbulent burning velocities (ST) of pre-vaporized iso-octane/air mixtures over wide ranges of the equivalence ratio (φ = 0.9–1.25, Le ≈ 2.94–0.93), the root-mean-square (r.m.s.) turbulent fluctuating velocity (u′ = 0–4.2 m/s), pressure p = 1–5 atm at T = 358 K and p = 0.5–3 atm at T = 373 K, where Le is the effective Lewis number. Results show that at any fixed p, T and u′, Le < 1 flames propagate faster than Le > 1 flames, of which the normalized iso-octane ST/SL data versus u′/SL are very scattering, where SL is the laminar burning velocity. But when the effect of Le is properly considered in some scaling parameters used in previous correlations, these large scattering iso-octane ST/SL data can be collapsed onto single curves by several modified general correlations, regardless of different φ, Le, T, p, and u′, showing self-similar propagation of turbulent spherical flames. The uncertainty analysis of these modified general correlations is also discussed.
A POMDP‐based long‐term transmission rate maximization for cognitive radio networks with wireless‐powered ambient backscatter

Wireless energy harvesting enables wireless‐powered communications to accommodate data services in a self‐sustainable manner over a long operational time. Along with energy harvesting, an ambient backscatter technique helps a secondary transmitter reflect existing radio frequency (RF) signal sources to communicate with a secondary receiver when the primary channel (PC) is utilized. However, secondary system performance is significantly affected by factors such as the availability of the primary channel, imperfect spectrum sensing, and energy‐constrained problems. Therefore, we propose a novel approach for wireless‐powered cognitive radio networks (CRNs) to improve the transmission performance of secondary systems. To reduce the dependence of the secondary system on RF sources, in the paper, we provide a new paradigm by integrating ambient backscattering with both RF and non‐RF wireless‐powered communications to facilitate secondary communications. On the basis of the sensing result in a time slot, the secondary transmitter can dynamically select the operational action: (a) backscattering, (b) harvesting, or (c) transmitting to maximize the long‐term achievable data transmission rate at the secondary receiver. In addition, the optimal action set for CRNs with wireless‐powered ambient backscatter is selected by the partially observable Markov decision process (POMDP), which maximizes an expected transmission rate calculated over a number of subsequent time slots. The proposed scheme aims to improve long‐term transmission rate of CRNs with wireless‐powered ambient backscatter in comparison with conventional schemes where an action is taken only to maximize the immediate reward in every single time slot.
EFFECT OF STRATEGIC CHANGE MANAGEMENT PRACTICES ON PERFORMANCE OF PUBLIC SECONDARY SCHOOLS: A SURVEY OF PUBLIC SECONDARY SCHOOLS IN KISII COUNTY

Strategic change management practices have been applied by many institutions while others rarely attempt to apply while some not applying at all. This results to discrepancies in the performances of institutions. This study focused on the effects of strategic change management practices on the performance of Public Secondary schools in Kisii County. The specific objectives were; to establish the effects of stakeholder’s management on Public Secondary schools performance in Kisii County to determine the effect of strategic planning on performance of Public Secondary schools in Kisii County, and to assess the effect of strategic leadership on performance of Public Secondary schools in Kisii County. The target population consisted of 274 Public Secondary schools principals in Kisii County. The data was analysed by use of statistical package of social science version 21. The study concluded that strategic planning had a positive significant effect on performance of secondary public secondary school. However there is a positive correlation between strategic leadership and public secondary schools performance. This implied that change in strategic change management practices results to relatively positive performance public secondary schools in Kisii County. Thus, there is significant relationship between strategic change management and public secondary schools performance. The study recommended that strategic leadership in public secondary school should be improved through strategic change management practices. Thus, the study suggested for another study to be conducted on the effect of strategic plans on performance of other private institutions. Key Words: Stakeholder’s Management, Strategic Planning, Strategic Leadership, Strategic Change CITATION: Mairura, V. S. , & Atambo, W. (2019). Effect of strategic change management practices on performance of public secondary schools: A survey of public secondary schools in Kisii County. The Strategic Journal of Business & Change Management, 6 (2), 1919 –1935.
Broadband Partially Reflecting Superstrate-Based Antenna for 60 GHz Applications

In this communication, a broadband low-profile partially reflecting superstrate (PRS)-based antenna is presented for 60 GHz applications. The PRS with an asymmetric pattern of circular metallic patches printed on one side of a thin dielectric slab improves the feed antenna gain from 6.5 to 18.5 dBi. A prototype antenna exhibits a peak gain of 18.8 dBi with a 3 dB gain bandwidth of 16.7%. Simulated and measured radiation patterns of the proposed antenna are highly directive toward broadside over a large operating bandwidth. The prototype antenna is well matched with a measured voltage standing wave ratio (VSWR) below 2 over a frequency range from 55.6 to 69.6 GHz, corresponding to a matching bandwidth of 22.4%. Fabrication limitations and assembly tolerances are also discussed. Overall, the prototype validates the high gain and wideband performance of the proposed antenna. The total area of the PRS is <inline-formula> <tex-math notation="LaTeX">$5.2\lambda _{0}^{2}$ </tex-math></inline-formula> and the overall height of the antenna is only <inline-formula> <tex-math notation="LaTeX">$0.66\lambda _{0}$ </tex-math></inline-formula> at the lowest operating frequency of 55.6 GHz.
Journal of Graph Algorithms and Applications Level Planar Embedding in Linear Time

A level graph G = (V, E, φ) is a directed acyclic graph with a mapping φ : V → {1, 2,. , k}, k ≥ 1, that partitions the vertex set V as V = V 1 ∪ V 2 ∪· · ·∪V k , V j = φ −1 (j), V i ∩ V j = ∅ for i = j, such that φ(v) ≥ φ(u) + 1 for each edge (u, v) ∈ E. The level planarity testing problem is to decide if G can be drawn in the plane such that for each level V i , all v ∈ V i are drawn on the line li = {(x, k − i) | x ∈ Ê}, the edges are drawn monotonically with respect to the vertical direction, and no edges intersect except at their end vertices. In order to draw a level planar graph without edge crossings, a level planar embedding of the level graph has to be computed. Level planar embeddings are characterized by linear orderings of the vertices in each V i (1 ≤ i ≤ k). We present an O(|V |) time algorithm for embedding level planar graphs. This approach is based on a level planarity test by Jünger, Leipert, and Mutzel (1998).
Big Data Optimization for Modern Communication Networks

The unprecedented big data in modern communication networks presents us opportunities and challenges. An efficient analytic method for the sheer volume of data is of significant importance for smart grid evolution, intelligent communication network management, efficient medical data management, personalized business model design and smart city development. Meanwhile, the huge volume of data makes it impractical to collect, store and processing in a centralized fashion. Moreover, the massive datasets are noisy, incomplete, heterogeneous, structured, prone to outliers, and vulnerable to cyber-attacks. Overall, we are facing a problem in which the classic resources of computation such as time, space, and energy, are intertwined in complex ways with the massive data sources, and new computational mathematical models as well as methodologies must be explored. With the rapid development of the modern communication networks comes the need of novel algorithms for large-scale data processing and optimization. In this thesis, we investigate the application of big data optimization methods for smart grid security and mobile data traffic management. Firstly, we review the parallel and distributed optimization algorithms based on an alternating direction method of multipliers for solving big data optimization problems. The mathematical backgrounds of the algorithms are given, and the implementations on large-scale computing facilities are also illustrated. Next, the applications of big data processing techniques for smart grid security are studied from two perspectives: how to exploit the inherent structure of the data, and how to deal with the huge size of the data sets. Explored problems are the sparse optimization approach for false data injection detection, and the distributed parallel approach for the security-constrained optimal power flow problem, respectively. Finally, we consider big data optimization methods for data traffic management in mobile cloud computing by two specific application cases: the mobile data offloading in a software defined network at the network edge, and the management of mobile cloud service request allocation and response routing. It is shown by numerical results that effective management and processing of big data have the potential to significantly improve smart grid security as well as resource utilization and service quality of the mobile cloud computing.
Network Coding in a Multicast Switch

The problem of serving multicast flows in a crossbar switch is considered. Intraflow linear network coding is shown to achieve a larger rate region than the case without coding. A traffic pattern is presented which is achievable with coding but requires a switch speedup when coding is not allowed. The rate region with coding can be characterized in a simple graph-theoretic manner, in terms of the stable set polytope of the "enhanced conflict graph". No such graph-theoretic characterization is known for the case of fanout-splitting without coding. The minimum speedup needed to achieve 100% throughput with coding is shown to be upper bounded by the imperfection ratio of the enhanced conflict graph, where the imperfection ratio measures a certain graph theoretic property of the given graph. When applied to K × N switches with unicasts and broadcasts only, this gives a bound of min(2K-1/K, 2N/N+1) on the speedup. This shows that speedup, which is usually implemented in hardware, can often be substituted by network coding, which can be done in software. Computing an offline schedule (using prior knowledge of the flow rates) is reduced to fractional weighted graph coloring. A graph-theoretic online scheduling algorithm (using only queue occupancy information) is also proposed, that stabilizes the queues for all rates within the rate region.
Diffuse TBI-induced expression of anxiety-like behavior coincides with altered glutamatergic function, TrkB protein levels and region-dependent pathophysiology in amygdala circuitry

Up to 50% of traumatic brain injury (TBI) survivors demonstrate persisting affective symptoms indicative of limbic system dysregulation, yet the pathophysiology underlying the symptoms is unclear. We hypothesize that TBI-induced pathophysiologic changes within distinct amygdala nuclei contribute to the expression of late-onset anxiety-like behavior. Adult, male Sprague-Dawley rats underwent midline fluid percussion injury or sham surgery. Anxiety-like behavior was assessed at 7 and 28 days post-injury (DPI) followed by assessment of real-time glutamate neurotransmission in the basolateral amygdala (BLA) and central nucleus of the amygdala (CeA) using glutamate-selective microelectrode arrays. In separate animal cohorts, the presence of neuropathology, astrocytosis, and microglial activation were assessed at 1, 7, and 28DPI. Protein levels of glutamatergic transporters (Glt-1, GLAST) and presynaptic modulators of glutamate release (mGluR2, TrkB, BDNF, and glucocorticoid receptors) were quantified using automated capillary western techniques at 28DPI. The expression of anxiety-like behavior at 28DPI coincided with decreased glutamate release and slower glutamate clearance in the CeA, not BLA. Changes in glutamate neurotransmission were independent of protein levels of glutamate transporters and mGluR2 receptors, neuropathology, and astrocytosis. At 1DPI, microglia in the CeA demonstrated a neuroinflammatory response. BDNF and TrkB were decreased at 28DPI in the amygdala. These data indicate that diffuse axonal injury instigates sequences of molecular, structural and functional changes in the amygdala that contribute to circuit dysregulation relevant to the expression of affective disorders. Translationally, diffuse axonal injury can influence severity and incidence of affective symptoms and should be addressed in the history of patients with affective disorders.
Linking organizational career management with Generation Y employees’ organizational identity: The mediating effect of meeting career expectations

ABSTRACT This study explores the link between organizational career management (OCM) and organizational identity in relation to the mediating effect of career expectation. Data were collected from 476 Generation Y hotel employees and was analyzed using Amos software of structural equation modeling (SEM). Study results suggest organizational career management is a positive predictor of career expectation, and career expectation positively affects organizational identity and career satisfaction. Furthermore, career expectation is a mediator between career management and organizational identity.
Determination of Debye temperatures and Lamb–Mössbauer factors for LnFeO3 orthoferrite perovskites (Ln  =  La, Nd, Sm, Eu, Gd)

Lanthanide orthoferrites have wide-ranging industrial uses including solar, catalytic and electronic applications. Here a series of lanthanide orthoferrite perovskites, LnFeO3 (Ln = La; Nd; Sm; Eu; Gd), prepared through a standard stoichiometric wet ball milling route using oxide precursors, has been studied. Characterisation through x-ray diffraction and x-ray fluorescence confirmed the synthesis of phase-pure or near-pure LnFeO3 compounds. 57Fe Mössbauer spectroscopy was performed over a temperature range of 10 K–293 K to observe hyperfine structure and to enable calculation of the recoil-free fraction and Debye temperature (θD) of each orthoferrite. Debye temperatures (Ln = La 474 K; Nd 459 K; Sm 457 K; Eu 452 K; Gd 473 K) and recoil-free fractions (Ln = La 0.827; Nd 0.817; Sm 0.816; Eu 0.812; Gd 0.826) were approximated through minimising the difference in the temperature dependent experimental centre shift and theoretical isomer shift, by allowing the Debye temperature and isomer shift values to vary. This method of minimising the difference between theoretical and actual values yields Debye temperatures consistent with results from other studies determined through thermal analysis methods. This displays the ability of variable-temperature Mössbauer spectroscopy to approximate Debye temperatures and recoil-free fractions, whilst observing temperature induced transitions over the temperature range observed. X-ray diffraction and Rietveld refinement show an inverse relationship between FeO6 octahedral volume and approximated Debye temperatures. Raman spectroscopy show an increase in the band positions attributed to soft modes of Ag symmetry, Ag(3) and Ag(5) from La to GdFeO3 corresponding to octahedral rotations and tilts in the [0 1 0] and [1 0 1] planes respectively.
A first principle evaluation of the adsorption mechanism and stability of volatile organic compounds into NaY zeolite

Abstract Removal of volatile organic compounds (VOCs) from indoor or outdoor environments is an urgent challenge for the protection of human populations. Inorganic sorbents such as zeolites are a promising solution to tackle this issue. Using dispersion corrected periodic DFT calculations, we have studied the interaction between sodium-exchanged faujasite zeolite and a large set of VOCs including aromatics, oxygenates and chlorinated compounds. The computed interaction energies range from about −25 (methane) to −130 kJ/mol (styrene). Methane is by far the less interacting specie with the NaY zeolite. All other VOCs present interaction energies higher in absolute value than 69 kJ/mol. Most of them show a similar adsorption strength, between −70 and −100 kJ/mol. While the electrostatic interactions are important in the case of oxygenates and acrylonitrile, van der Waals interactions predominate in hydrocarbons and chlorides. By monitoring the variation of molecular bond lengths of the different VOCs before and after adsorption, we have then evaluated the tendency of adsorbate to react and form by-products, since a significant stretching would evidently lead to the activation of the bond. While hydrocarbons, tetrachloroethylene and acrylonitrile seem to be not activated upon adsorption, all oxygenates and 1,1,2-trichloroethane could possibly react once adsorbed.