bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimizing hadoop parameter settings with gene expression programming guided PSO
Authors: Khan Mukhtaj , Huang Zhengwen , Li Maozhen , Taylor Gareth A. , Khan Mushtaq 
Published: February 2016

SummaryHadoop MapReduce has become a major computing technology in support of big data analytics. The Hadoop framework has over 190 configuration parameters, and some of them can have a significant effect on the performance of a Hadoop job. Manually tuning the optimum or near optimum values of these parameters is a challenging task and also a time consuming process. This paper optimizes the performance of Hadoop by automatically tuning its configuration parameter settings. The proposed work first employs gene expression programming technique to build an objective function based on historical job running records, which represents a correlation among the Hadoop configuration parameters. It then employs particle swarm optimization technique, which makes use of the objective function to search for optimal or near optimal parameter settings. Experimental results show that the proposed work enhances the performance of Hadoop significantly compared with the default settings. Moreover, it outperforms both rule‐of‐thumb settings and the Starfish model in Hadoop performance optimization. © 2016 The Authors. Concurrency and Computation: Practice and Experience Published by John Wiley & Sons Ltd.
Knowledge diffusion in complex networks
Authors: Zhang Yichao , Li Xing , Aziz‐alaoui M. A. , Bertelle Cyrille , Guan Jihong , Zhou Shuigeng 
Published: February 2016

SummaryModern communication networks and social networks are the main tunnels of knowledge diffusion. Knowledge diffusion in complex networks is different from the epidemic‐like information spreading, because individuals are willing to learn and spread knowledge to their friends and the learning process can hardly be achieved in a few conversations. In this paper, we investigate the important issue as what topological structure is suitable for knowledge diffusion. We propose a new knowledge diffusion model, where both learning and forgetting mechanisms are considered. In this model, individuals can play imparter and learner simultaneously. Comparing knowledge diffusion on a series of complex topologies, we observe that the individuals with a large degree can quickly learn more knowledge, who are beneficial to knowledge diffusion. Our results surprisingly reveal that the networks with high degree‐heterogeneity are likely to be suitable for knowledge diffusion. Our finding suggests that enhancing the degree heterogeneity of existing social networks may help to improve the performance of knowledge diffusion. This result is well confirmed by our extensive simulation results. Our model therefore provides a theoretical framework for understanding knowledge diffusion in complex topologies. Copyright © 2016 John Wiley & Sons, Ltd.
Multiple multicast group key management for the Internet of People
Authors: Zhong Hong , Luo Weiya , Cui Jie 
Published: February 2016

SummaryGroup key management (GKM) is an important research topic in mobile multicast communication nowadays. With the development of multiple services based on groups, it may be a very common phenomenon that multiple multicast groups coexist under a single network, and mobile subscribers can subscribe a variety of these services. Nevertheless, the current GKM schemes are focused on the communication in only a single group, which do not fit for multiple multicast group scenarios because of inefficient use of keys. In this paper, we propose a novel GKM scheme for multiple multicast groups in the Internet of People, called the area based multiple GKM (AMGKM) scheme. AMGKM can be implemented in wireless mobile network environments such as VANETs, and supports users to move across the wireless networks in the Internet of People while users subscribing to multiple multicast services with minimized communication overheads. AMGKM can also effectively mitigate the investment pressure of signaling load, and satisfy both the forward and the backward security and support membership changes. Our proposed method exploits the master key encryption (MKE) algorithm for efficiently reducing the rekeying overheads while providing intense security. Copyright © 2016 John Wiley & Sons, Ltd.
Efficient Blue‐Colored Solid‐State Dye‐Sensitized Solar Cells: Enhanced Charge Collection by Using an in Situ Photoelectrochemically Generated Conducting Polymer Hole Conductor
Authors: Zhang Jinbao , Vlachopoulos Nick , Hao Yan , Holcombe Thomas W. , Boschloo Gerrit , Johansson Erik M. J. , Grätzel Michael , Hagfeldt Anders 
Published: February 2016

AbstractA high power conversion efficiency (PCE) of 5.5 % was achieved by efficiently incorporating a diketopyrrolopyrrole‐based dye with a conducting polymer poly(3,4‐ethylenediothiophene) (PEDOT) hole‐transporting material (HTM) that was formed in situ, compared with a PCE of 2.9 % for small molecular spiro‐OMeTAD‐based solid‐state dye solar cells (sDSCs). The high PCE for PEDOT‐based sDSCs is mainly attributed to the significantly enhanced charge‐collection efficiency, as a result of the three‐order‐of‐magnitude higher hole conductivity (0.53 S cm−1) compared with that of the widely used low molecular weight HTM spiro‐OMeTAD (3.5×10−4 S cm−1).
Hydrogenolysis of Glycerol to 1,3‐propanediol under Low Hydrogen Pressure over WOx‐Supported Single/Pseudo‐Single Atom Pt Catalyst
Authors: Wang Jia , Zhao Xiaochen , Lei Nian , Li Lin , Zhang Leilei , Xu Shutao , Miao Shu , Pan Xiaoli , Wang Aiqin , Zhang Tao 
Published: February 2016

AbstractSingle/pseudo‐single atom Pt catalyst was prepared on mesoporous WOx. The large surface area and abundant oxygen vacancies of WOx improve the Pt dispersion and stabilize the Pt isolation. This newly prepared catalyst exhibited outstanding hydrogenolysis activity under 1 MPa H2 pressure with a very high space–time yield towards 1,3‐propanediol (3.78 g gPt−1 h−1) in Pt–W catalysts. The highly isolated Pt structure is thought to contribute to the excellent H2 dissociation capacity over Pt/WOx. The high selectivity towards 1,3‐propanediol is attributed to the heterolytic dissociation of H2 at the interface of Pt and WOx (providing specific Brønsted acid sites and the concerted dehydration–hydrogenation reaction) and the bond formation between glycerol and WOx, which favors/stabilizes the formation of a secondary carbocation intermediate as well as triggers the redox cycle of the W species (W6+⇄W5+).
The Thermophysical Properties of Iron Plasma
Authors: Apfelbaum E. M. 
Published: February 2016

AbstractThe pressure, internal energy, conductivity, thermal conductivity and thermal power of Iron plasma have been calculated at temperatures 10–100 kK and densities less than 2 g/cm3. The plasma composition has been obtained by means of corresponding system of coupled mass action laws. We have considered the atom ionization up to +6. The transport coefficients have been obtained within the relaxation time approximation. The comparison of our results with available measurement and calculation data has shown very good agreement for the pressure and less good agreement for the conductivity. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Dynamics of Dust Structures under Magnetic Field in Stratified Glow Discharge
Authors: Karasev V. Yu. , Dzlieva E. S. , Pavlov S. I. , Ermolenko M. A. , Novikov L. A. , Maiorov S. A. 
Published: February 2016

AbstractA detailed research of mechanisms causing the rotation of dust structures formed in striations of the glow discharge in longitudinal magnetic field is presented. Literary data speak about sign‐variable dependence of angular velocity of dust structure on the magnetic field. The first done experiment proves that ion drag force is the reason of rotation with the negative projection of angular velocity on magnetic induction in small magnetic fields. The method of a variation of an ion flux in mixes of gases was used for the research. In the second experiment the gas rotation arising because of eddy electron current in the magnetic field was revealed by the method of probing of the discharge by dust particles. Estimates show that a prevalence of the mechanism of rotation of dust structures and correspondingly the direction of rotation depends both on discharge conditions and on the size of dust particles. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Dusty Plasma in a Non‐Self‐Sustained Gas Discharge at Atmospheric Pressure
Authors: Fiippov A. V. , Babichev V. N. , Pal' A. F. , Starostin A. N. , Cherkovets V. E. 
Published: February 2016

AbstractA non‐self‐sustained (NSS) discharge at atmospheric gas pressure containing dust particles is studied. The NSS discharge was controlled by a stationary electron beam with energy up to 120 keV. A numerical model of the NSS discharge is based on the drift‐diffusion approach for electrons and ions and self‐consistently takes into account effects of the dust particles on the electron and ion densities. The dusty component is described by the number balance equation and the equation of motion for dust particles with allowance for the Stokes force, gravity force and electric force in the cathode sheath. Interaction between dust particles is described in the self‐consistent field approximation. It is established that, at a given gas ionization rate and given applied voltage, there is a critical dust particle size above which the levitation condition in the cathode sheath cannot be satisfied. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
CD4 results with a bias larger than hundred cells per microliter can have a significant impact on the clinical decision during treatment initiation of HIV patients
Authors: Daneau Géraldine , Buyze Jozefien , Wade Djibril , Diaw Papa Alassane , Dieye Tandakha Ndeye , Sopheak Thai , Florence Eric , Lynen Lutgarde , Kestens Luc 
Published: February 2016

BackgroundCD4 counts are currently used to assess HIV patients for treatment eligibility and to monitor antiretroviral response to treatment. The emerging point‐of‐care devices could fill an important gap in resource‐limited settings. However, the accuracy of CD4‐counting instruments is diverse and data on how CD4 measurement errors have an impact on clinical decisions are lacking.MethodsClinicians were queried on the use of CD4 results in their clinical setting. Subsequently, the effect of CD4 measurement errors on treatment initiation was put in a statistical model. Based on clinical CD4 databases from Belgium, Cambodia, and Senegal, the percentage of unchanged clinical decisions was calculated (treatment initiation should start within a 3‐month delay [one visit]) for escalating CD4 measurement errors, taking into account the strict or preventive application of CD4 thresholds at 350 or 500 cells/µl used by clinicians.ResultsTo ensure that the treatment was initiated appropriately for at least 95% of patients, an error of 5 − 10 cells/µl was allowed. This is significantly smaller than the bias of ±50 cells/µl most clinicians considered acceptable. For limits of agreement (LOA, 1.96 x error) of 100 cells/µl, corresponding to most CD4 instrument evaluations, the misclassification rate of patients was found to be 3 − 28% at the threshold of 350 cells/µl (strict or flexible), and 13 − 20% at 500 cells/µl.ConclusionsThe maximum allowed CD4 bias on results from new CD4 technologies should not exceed 50 cells/µl (LOA 100 cells/µl) when applied for treatment initiation, to ensure at least 72% of correct clinical decisions. © 2016 International Clinical Cytometry Society
Dynamic switch migration towards a scalable SDN control plane
Authors: Cheng Guozhen , Chen Hongchang , Hu Hongchao , Lan Julong 
Published: February 2016

SummaryDistributed control plane is a promising approach to scalable software‐defined networking (SDN). Live migration of switches from controllers that are overloaded to those that are underutilized may be a solution to handle peak switch traffic using available control resource. However, such migration has to be performed with a well‐designed mechanism to fully utilize available resources in all three resource dimensions: CPU, bandwidth, and memory. In this article, we first provide a resource model for SDN and reduce the switch migration decision to a centralized resource utilization maximization problem under constraints of CPU, bandwidth, and memory. Second, we show that the problem of maximizing resource utilization in an SDN is equivalent to that of maximizing game players' profits in the context of non‐cooperative game theory. Taking controllers and switches as game players and commodities respectively, the player policy is how to migrate switches among the control plane. Finally, we implement a proof of concept, called GAME‐Switch Migration (GAME‐SM). The numerical experiments using Mininet emulator validate nice properties of our game model in enhancing the performance of control plane in SDN. Copyright © 2016 John Wiley & Sons, Ltd.
Multilevel space–time trellis coded cooperation with channel state information at transmitter
Authors: Aneja Sakshi , Sharma Sanjay 
Published: February 2016

SummaryIn this paper, the authors propose a system where a number of cooperating mobile nodes transmit information to a common destination node. Each cooperating node has a set of decoders to detect the information of other nodes and a set of encoders to further encode the decoded information as well as its own information using multilevel space–time trellis coding (MLSTTC) scheme. The coded information is mapped using multi‐resolution modulation partitioning to M‐ary quadrature amplitude modulation constellation. The mapped symbols are weighted based on the available channel state information at transmitting nodes. The weighting of transmitting symbols provides beamforming resulting in receive signal‐to‐noise ratio gain. The weighted symbols are sent to destination node through two transmit antennas. If the information of other nodes has been correctly decoded at the cooperating node, then the destination node receives the information of each node as many times as there are number of transmitting nodes, thus achieving full diversity order. A multistage Viterbi decoder is used at the destination node to extract information of each mobile node. The results indicate that the performance of proposed cooperative MLSTTC system is superior to non‐cooperative MLSTTC system. Copyright © 2016 John Wiley & Sons, Ltd.
The extent of shifts in vegetation phenology between rural and urban areas within a human‐dominated region
Authors: Dallimer Martin , Tang Zhiyao , Gaston Kevin J. , Davies Zoe G. 
Published: February 2016

AbstractUrbanization is one of the major environmental challenges facing the world today. One of its particularly pressing effects is alterations to local and regional climate through, for example, the Urban Heat Island. Such changes in conditions are likely to have an impact on the phenology of urban vegetation, which will have knock‐on implications for the role that urban green infrastructure can play in delivering multiple ecosystem services. Here, in a human‐dominated region, we undertake an explicit comparison of vegetation phenology between urban and rural zones. Using satellite‐derived MODIS‐EVI data from the first decade of the 20th century, we extract metrics of vegetation phenology (date of start of growing season, date of end of growing season, and length of season) for Britain's 15 largest cities and their rural surrounds. On average, urban areas experienced a growing season 8.8 days longer than surrounding rural zones. As would be expected, there was a significant decline in growing season length with latitude (by 3.4 and 2.4 days/degree latitude in rural and urban areas respectively). Although there is considerable variability in how phenology in urban and rural areas differs across our study cities, we found no evidence that built urban form influences the start, end, or length of the growing season. However, the difference in the length of the growing season between rural and urban areas was significantly negatively associated with the mean disposable household income for a city. Vegetation in urban areas deliver many ecosystem services such as temperature mitigation, pollution removal, carbon uptake and storage, the provision of amenity value for humans and habitat for biodiversity. Given the rapid pace of urbanization and ongoing climate change, understanding how vegetation phenology will alter in the future is important if we wish to be able to manage urban greenspaces effectively.
Responses of ground‐dwelling arthropods to surface flow drying in channels and adjacent habitats along Mediterranean streams
Authors: Sánchez‐Montoya María del Mar , von Schiller Daniel , Ruhí Albert , Pechar Giuliano Sting , Proia Lorenzo , Miñano Jesús , Vidal‐Abarca María Rosario , Suárez María Luisa , Tockner Klement 
Published: February 2016

AbstractIntermittent streams are dynamic ecosystems that alternate between dry and wet states. Despite their global dominance, we have scant information about the effects of surface flow drying on terrestrial arthropods in channel and adjacent terrestrial habitats. In the present study, we used pitfall traps to characterise the terrestrial arthropod assemblages along lateral gradients (channel, riparian, and upland habitats) in perennial and intermittent reaches of two contrasting Mediterranean intermittent streams (Rogativa and Fuirosos streams). Simultaneously, we assessed changes in assemblage composition and structure on five sampling occasions over the entire drying period (i.e. 29 days). The composition of arthropod assemblages differed among streams, flow regimes, habitat types, and sampling dates. In contrast, depending on the stream, taxonomic richness and total abundance were similar between perennial and intermittent reaches, but differed among habitat types. Formicidae, Araneae, Collembola, and Coleoptera explained most of the differences between flow regimes and habitat types in both streams. In Rogativa stream, arthropod abundances peaked in the dry channel and increased with drying time, while abundances decreased in riparian and upland habitats. It implies that the dry channel may be colonized by riparian and upland arthropods to a greater or lesser extent depending on the stream and the specific landscape context. Our results emphasize the importance of dry channels as temporary habitats for terrestrial arthropod assemblages. Thus, the dry period should be considered explicitly when assessing biodiversity of and establishing management strategies for intermittent streams and their fringing riparian and upland areas. Copyright © 2016 John Wiley & Sons, Ltd.
Synthesis, Characterization, Reactivity, Catalytic Activity, and Antiamoebic Activity of Vanadium(V) Complexes of ICL670 (Deferasirox) and a Related Ligand
Authors: Maurya Mannar R. , Sarkar Bithika , Avecilla Fernando , Tariq Saba , Azam Amir , Correia Isabel 
Published: February 2016

AbstractThe reactions of [VIVO(acac)2] (acac = acetylacetonato) with two ONO tridentate ligands, 4‐[3,5‐bis(2‐hydroxyphenyl)‐1,2,4‐triazol‐1‐yl]benzoic acid (H2L1, I) and 3,5‐bis(2‐hydroxyphenyl)‐1‐phenyl‐1,2,4‐triazole (H2L2, II) in methanol lead to the formation of the oxidovanadium(V) complexes [VVO(µ‐L1)(OMe)]2 (1) and [VVO(µ‐L2)(OMe)]2 (2). In the presence of KOH/CsOH, they give the corresponding dioxidovanadium(V) complexes. The isolated complexes K(H2O)[VVO2(L1)] (3), K(H2O)[VVO2(L2)] (4), Cs(H2O)[VVO2(L1)] (5), and Cs(H2O)[VVO2(L2)] (6) along with 1 and 2 have been characterized by various spectroscopic techniques (FTIR; UV/Vis; 1H, 13C, and 51V NMR), elemental analysis, thermal studies, MALDI‐TOF MS analysis, and single‐crystal analysis of 1a (complex 1 grown together with 4,4′‐bipyridyl). The oxidative bromination of thymol, catalyzed by these complexes, in the presence of KBr and HClO4 with H2O2 as an oxidant, gives 2‐bromothymol, 4‐bromothymol, and 2,4‐dibromothymol. The amounts of the catalyst, oxidant, KBr, HClO4, and the solvent were optimized for the maximum conversion of thymol. Both ligands and all complexes were tested in vitro for antiamoebic activity against the HM1:IMSS strain of Entamoeba histolytica by a microdilution method. The complexes are more potent amoebicidal agents than the standard drug metronidazole. Toxicity studies against a human cervical cancer cell line (HeLa) also confirm that these compounds are less cytotoxic than metronidazole.
Synthesis and Properties of Organic Hexahalocerate(III) Salts
Authors: Pohako‐Esko Kaija , Wehner Tobias , Schulz Peter S. , Heinemann Frank W. , Müller‐Buschbaum Klaus , Wasserscheid Peter 
Published: February 2016

AbstractA series of hexahalocerate(III) salts with the general formula [cation]3[CeHal6] have been prepared by dissolving anhydrous cerium trihalides in imidazolium halide ionic liquids. Complexes with different anions, [CeCl6]3–, [CeBr6]3– and [CeBr3Cl3]3–, were synthesized and their cationic alkyl chains were varied. To confirm the structures of the prepared salts, X‐ray crystallography was used to characterize [BMIM]3[CeCl6]. Two different crystal structures were found: [BMIM]3[CeCl6] and the linear coordination polymer [BMIM]x[Ce(µ‐Cl)2Cl2(EtOH)2]x containing coordinated solvent. All the synthesized compounds were characterized by DSC and TGA. The influence of the cationic and anionic structures on the melting points and decomposition temperatures is discussed. Furthermore, the Ce‐containing salts [BMIM]3[CeHal6] show interesting photoluminescence properties: intense Ce3+‐based 5d–4f‐centred emission from the soft UV‐B region to the border of visible light is observed that is driven both by direct excitation of Ce3+ as well as by a sensitizer effect of the [BMIM]+ cation.
Methoxyphenyl Substituted Bis(picolyl)phosphines and Phosphine Oxides
Authors: Hettstedt Christina , Unglert Martin , Mayer Robert J. , Frank Anna , Karaghiosoff Konstantin 
Published: February 2016

AbstractThree new derivatives of methoxyphenyl‐substituted bis(picolyl)phosphines 3–5, the CH2TMS substituted bis(picolyl)phosphine (6) and related phosphine oxides 2b–5b have been synthesized. Syntheses were accomplished by reacting the corresponding dichlorophosphines with picolylTMS (7). An improved synthesis of most of the starting materials is also presented and enables increased ligand yields in all cases. The new bis(picolyl)phosphines and phosphine oxides are extensively characterized by 1H, 13C and 31P NMR spectroscopy and, in the case of the literature known tris(picolyl)phosphine (2) and its new phosphine oxide derivative, single‐crystal X‐ray analysis was applied to structure elucidation efforts. The determination of the molecular structure of (o‐methoxyphenyl)dichlorophosphine (3a) was achieved by X‐ray analysis of a co‐crystal consisting of 3a and its rare phosphonic anhydride derivative 8.