bluuebunny/crossref_metadata_2025 huggingface dataset:
The case for colocation of high performance computing workloads
Authors: Breslow Alex D. , Porter Leo , Tiwari Ananta , Laurenzano Michael , Carrington Laura , Tullsen Dean M. , Snavely Allan E.
Published: December 2013

The current state of practice in supercomputer resource allocation places jobs from different users on disjoint nodes both in terms of time and space. While this approach largely guarantees that jobs from different users do not degrade one another's performance, it does so at high cost to system throughput and energy efficiency. This focused study presents job striping, a technique that significantly increases performance over the current allocation mechanism by colocating pairs of jobs from different users on a shared set of nodes. To evaluate the potential of job striping in large‐scale environments, the experiments are run at the scale of 128 nodes on the state‐of‐the‐art Gordon supercomputer. Across all pairings of 1024 process network‐attached storage parallel benchmarks, job striping increases mean throughput by 26% and mean energy efficiency by 22%. On pairings of the real applications Gyrokinetic Toroidal Code (GTC), Large‐scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), and MIMD Lattice Computation (MILC) at equal scale, job striping improves average throughput by 12% and mean energy efficiency by 11%. In addition, the study provides a simple set of heuristics for avoiding low performing application pairs. Copyright © 2013 John Wiley & Sons, Ltd.
The density and spatial arrangement of the invasive oyster Crassostrea gigas determines its impact on settlement of native oyster larvae
Authors: Wilkie Emma M. , Bishop Melanie J. , O'Connor Wayne A.
Published: December 2013

Understanding how the density and spatial arrangement of invaders is critical to developing management strategies of pest species. The Pacific oyster, Crassostrea gigas, has been translocated around the world for aquaculture and in many instances has established wild populations. Relative to other species of bivalve, it displays rapid suspension feeding, which may cause mortality of pelagic invertebrate larvae. We compared the effect on settlement of Sydney rock oyster, Saccostrea glomerata, larvae of manipulating the spatial arrangement and density of native S. glomerata, and non‐native C. gigas. We hypothesized that while manipulations of dead oysters would reveal the same positive relationship between attachment surface area and S. glomerata settlement between the two species, manipulations of live oysters would reveal differing density‐dependent effects between the native and non‐native oyster. In the field, whether oysters were live or dead, more larvae settled on C. gigas than S. glomerata when substrate was arranged in monospecific clumps. When, however, the two species were interspersed, there were no differences in larval settlement between them. By contrast, in aquaria simulating a higher effective oyster density, more larvae settled on live S. glomerata than C. gigas. When C. gigas was prevented from suspension feeding, settlement of larvae on C. gigas was enhanced. By contrast, settlement was similar between the two species when dead. While the presently low densities of the invasive oyster C. gigas may enhance S. glomerata larval settlement in east Australian estuaries, future increases in densities could produce negative impacts on native oyster settlement. Synthesis and applications: Our study has shown that both the spatial arrangement and density of invaders can influence their impact. Hence, management strategies aimed at preventing invasive populations reaching damaging sizes should not only consider the threshold density at which impacts exceed some acceptable limit, but also how patch formation modifies this.
An experimental heat wave changes immune defense and life history traits in a freshwater snail
Authors: Leicht Katja , Jokela Jukka , Seppälä Otto
Published: December 2013

The predicted increase in frequency and severity of heat waves due to climate change is expected to alter disease dynamics by reducing hosts' ability to resist infections. This could take place via two different mechanisms: (1) through general reduction in hosts' performance under harsh environmental conditions and/or (2) through altered resource allocation that reduces expression of defense traits in order to maintain other traits. We tested these alternative hypotheses by measuring the effect of an experimental heat wave (25 vs. 15°C) on the constitutive level of immune defense (hemocyte concentration, phenoloxidase [PO]‐like activity, antibacterial activity of hemolymph), and life history traits (growth and number of oviposited eggs) of the great pond snail Lymnaea stagnalis. We also manipulated the exposure time to high temperature (1, 3, 5, 7, 9, or 11 days). We found that if the exposure to high temperature lasted <1 week, immune function was not affected. However, when the exposure lasted longer than that, the level of snails' immune function (hemocyte concentration and PO‐like activity) was reduced. Snails' growth and reproduction increased within the first week of exposure to high temperature. However, longer exposures did not lead to a further increase in cumulative reproductive output. Our results show that short experimental heat waves do not alter immune function but lead to plastic responses that increase snails' growth and reproduction. Thus, although the relative expression of traits changes, short experimental heat waves do not impair snails' defenses. Negative effects on performance get pronounced when the heat waves are prolonged suggesting that high performance cannot be maintained over long time periods. This ultimately reduces the levels of defense traits.
Synthesis and Optical Properties of Salicylaldimine‐Based Diboron Complexes
Authors: Dhanunjayarao Kunchala , Mukundam Vanga , Ramesh Mamidala , Venkatasubbaiah Krishnan
Published: December 2013

New salicylaldimine‐based diboron complexes 1–3 have been synthesized and characterized by multinuclear NMR spectroscopy, mass spectrometry, and single‐crystal X‐ray analysis (1 and 3). The photophysical and electrochemical properties of these compounds have been investigated experimentally and with theoretical calculations; their properties suggest that these compounds could have potential applications for the manufacture of optoelectronic devices.
Next‐generation technologies and data analytical approaches for epigenomics
Authors: Mensaert Klaas , Denil Simon , Trooskens Geert , Van Criekinge Wim , Thas Olivier , De Meyer Tim
Published: December 2013

Epigenetics refers to the collection of heritable features that modulate the genome–environment interaction without being encoded in the actual DNA sequence. While being mitotically and sometimes even meiotically transmitted, epigenetic traits often demonstrate extensive flexibility. This allows cells to acquire diverse gene expression patterns during differentiation, but also to adapt to a changing environment. However, epigenetic alterations are not always beneficial to the organism, as they are, for example, frequently identified in human diseases such as cancer. Accurate and cost‐efficient genome‐scale profiling of epigenetic features is thus of major importance to pinpoint these “epimutations,” for example, to monitor the epigenetic impact of environmental exposure. Over the last decade, the field of epigenetics has been revolutionized by several innovative “epigenomics” technologies exactly addressing this need. In this review, we discuss and compare widely used next‐generation methods to assess DNA methylation and hydroxymethylation, noncoding RNA expression, histone modifications, and nucleosome positioning. Although recent methods are typically based on “second‐generation” sequencing, we also pay attention to still commonly used array‐ and PCR‐based methods, and look forward to the additional advantages of single‐molecule sequencing. As the current bottleneck in epigenomics research is the analysis rather than generation of data, the basic difficulties and problem‐solving strategies regarding data preprocessing and statistical analysis are introduced for the different technologies. Finally, we also consider the complications associated with epigenomic studies of species with yet unsequenced genomes and possible solutions. Environ. Mol. Mutagen. 55:155–170, 2014. © 2013 Wiley Periodicals, Inc.
Data Dashboard as Evaluation and Research Communication Tool
Authors: Smith Veronica S.
Published: December 2013

Data dashboards are visual displays that feature the most important information needed to achieve specific goals captured on a single screen. Effective dashboards should be designed as monitoring tools that are understood at a glance. Dashboards are useful tools because they can leverage visual perception to communicate dense amounts of data clearly and concisely. They are typically used in the communication phase of evaluation; however, in the case of analytical dashboards, they may also be used in the analysis phase. Strategic, analytical, and operational dashboards are different dashboard types used to meet different communication needs. This chapter highlights keys to realizing the potential of data dashboards by describing appropriate use, effective practices for designing and creating these tools, how to evaluate dashboards, and software that can be used to create dashboards. © Wiley Periodicals, Inc., and the American Evaluation Association.
The Contrasting Effects of Coaching Style on Task Performance: The Mediating Roles of Subjective Task Complexity and Self‐Set Goal
Authors: Hui Ray Tak‐yin , Sue‐Chan Christina , Wood Robert E.
Published: December 2013

The effects of two coaching styles, one guidance and one facilitation, on the performance of coached and transfer tasks were examined in an experimental study. With the aim of improving and enhancing individual performance, guidance coaching entails the coach as a role model, delivering clear expectations and feedback about how to improve in a directive manner, while facilitation coaching involves the coach's helping the individual to explore and evaluate the task and self‐developing the correct responses for improving performance. Tests of the mediating effects of self‐set goals, which are defined as desired levels of performance to be attained on a task, and subjective task complexity, which is defined as an individual's perception of the complexity of a task, on the coaching style–performance relationship were also conducted. Participants (n= 127) were coached in the use of two software programs, PowerPoint and Excel 2007. The results showed that guidance coaching is more effective for improving coached task performance than facilitation coaching, while facilitation coaching is more effective for improving transfer task performance than guidance coaching. Subjective task complexity and self‐set performance goals mediated the effects of coaching style on the performance of both coached and transfer tasks. Implications for theory and managerial practice are discussed.
Invited Reaction: The Contrasting Effects of Coaching Style on Task Performance: The Mediating Roles of Subjective Task Complexity and Self‐Set Goal
Authors: Kim Sewon , Egan Toby
Published: December 2013

Although part of managerial development and practice for some time, managerial coaching is an emerging area of research. Given the relative lack of empirical research, the study by Hui, Sue‐Chan, and Wood in this issue of HRDQ contributes to our understanding of the influence of coaching style on in‐role performance, and presents a mediating mechanism. Using the sample of 127 participants, this study used an experimental design to examine the impact of two different coaching styles (guidance and facilitation) on two different types of task performance (coached task and transfer task). Mediating roles of two cognitive variables (subjective task complexity and self‐set goal) also have been explored. The approach taken by Hui et al. led to interesting findings and insights toward fruitful prospective studies in this underresearched topic area. Concurrently, the sampling frame utilized and other limitations offered by the authors present opportunities for future exploration in other organizational contexts.
Practice and Research in Career Counseling and Development—2012
Authors: Bikos Lynette H. , Dykhouse Elizabeth C. , Boutin Stephen K. , Gowen Melissa J. , Rodney Heather E.
Published: December 2013

This annual review of the 2012 career development/vocational psychology literature includes 191 empirical (69%) and conceptual (31%) articles from career, counseling, development, and international journals. The review is divided into 4 major areas: professional issues, work and well‐being, life‐span perspectives, and career theory and concepts. Subsumed within these clusters are foci on the status of career/vocational guidance around the globe, the career development experiences of immigrants, and the effects of economic stress. The authors offer three summarizing impressions. First, the 2012 collection is definitively global; this is a credit to the individual and institutional dimensions of the counseling profession. Second, the research articles represent a wide array of methodological approaches, and researchers have made wise research design choices for their areas of inquiry. Third, there is a true professional responsiveness to the needs of the world. It is suggested that the 2012 literature reflects Parsons's early vision of social justice and multiculturalism.
BORN FREE to Integrated Life Planning: Advancing Equity in Career Development
Authors: Hansen Sunny , Tovar Lynn Z.
Published: December 2013

BORN FREE and Integrated Life Planning (ILP) are two efforts that have advanced equity within career development. This article reviews the concepts of BORN FREE and ILP, connecting both efforts to current visions of social justice.
Victim Gender, Number of Perpetrators, and Interpersonal Interaction in Stranger Rape: An Analysis of Direct and Moderator Effects
Authors: Lundrigan Samantha
Published: December 2013

This study examined the direct and moderator effects of number of perpetrators and gender of victim on interpersonal behaviour in stranger rape. Crime scene behaviours representative of hostility, involvement, control, and offender penetration in rape were examined for 496 UK, police‐recorded cases of stranger rape. Cases were grouped according to victim gender (male or female) and number of perpetrators (lone or multiple). This resulted in four groups (lone female, lone male, multiple female, and multiple male) with 124 cases in each. Binary logistic regression and one‐way analysis of variance were used to investigate the relationships between the two predictor variables and 11 criterion variables.

Significant direct effects of number of perpetrators were found whereby multiple perpetrator offences were more likely to involve violence and less likely to involve involvement interactions than lone perpetrator offences. Significant direct effects of victim gender were also found whereby male victims were more likely than female victims to experience hostile interactions and be threatened with a weapon and were less likely to experience offender penetration and involvement interactions. Significant crossover interactions were also found for four hostility variables. The utility of the findings are discussed in relation to crime prevention, victim support, and offender intervention. Copyright © 2013 John Wiley & Sons, Ltd.
Dorsal hump morphology in pink salmon (Oncorhynchus gorbuscha)
Authors: Susuki Kenta , Ichimura Masaki , Koshino Yosuke , Kaeriyama Masahide , Takagi Yasuaki , Adachi Shinji , Kudo Hideaki
Published: December 2013

Mature male Pacific salmon (Genus Oncorhynchus) develop a dorsal hump, as a secondary male sexual characteristic, during the spawning period. Previous gross anatomical studies have indicated that the dorsal humps of salmon are mainly composed of cartilaginous tissue (Davidson [1935] J Morphol 57:169–183.) However, the histological and biochemical characteristics of such humps are poorly understood. In this study, the detailed microstructures and components of the dorsal humps of pink salmon were analyzed using histochemical techniques and electrophoresis. In mature males, free interneural spines and neural spines were located in a line near to the median septum of the dorsal hump. No cartilaginous tissue was detected within the dorsal hump. Fibrous and mucous connective tissues were mainly found in three regions of the dorsal hump: i) the median septum, ii) the distal region, and iii) the crescent‐shaped region. Both the median septum and distal region consisted of connective tissue with a high water content, which contained elastic fibers and hyaluronic acid. It was also demonstrated that the lipid content of the dorsal hump connective tissue was markedly decreased in the mature males compared with the immature and maturing males. Although, the crescent‐shaped region of the hump consisted of connective tissue, it did not contain elastic fibers, hyaluronic acid, or lipids. In an ultrastructural examination, it was found that all of the connective tissues in the dorsal hump were composed of collagen fibers. Gel electrophoresis of collagen extracts from these tissues found that the collagen in the dorsal hump is composed of Type I collagen, as is the case in salmon skin. These results indicate that in male pink salmon the dorsal hump is formed as a result of an increase in the amount of connective tissue, rather than cartilage, and the growth of free interneural spines and neural spines. J. Morphol. 275:514–527, 2014. © 2013 Wiley Periodicals, Inc.
Charcoal in Amazonian paddy soil—Nutrient availability, rice growth and methane emissions
Authors: Barbosa de Sousa Áurea Maria , Soares Santos Raimundo Reginaldo , Gehring Christoph
Published: December 2013

We investigated the effects of charcoal under flooded (anoxic) rice cultivation at low and high fertilizer levels during 2 y in the Maranhão lowlands, eastern periphery of Amazonia. Two applications (at onset of first and second year) of 15 Mg ha–1 of fine (< 2 mm) charcoal derived from the endocarp of the babassu (Attalea speciosa Mart.) palm nut had little influence on soil fertility, rice growth, yield, and nutritional status. Exception to this were negative impacts of charcoal on first‐year N availability, with lower sub‐superficial soil NH$ _4^+ $ availability paired with lower rice tissue N and a responsiveness of grain yields to (mainly N‐) fertilization following charcoal application. This N‐limitation effect was, however, limited to the first year and—though statistically significant—without agronomic relevance. The most consistent charcoal effect on flooded‐soil fertility was the strong increase in K availability in the second year, at low and to a lesser extent at intermediate, but not at high fertilizer level. Low K concentrations of our charcoal exclude the possibility of direct K inputs via charcoal, suggesting other indirect mechanisms for K availability increases. Methane fluxes in the second year were significantly reduced (–43.8%) by charcoal application, charcoal‐induced reductions were stronger under high‐ (–47.3%) than under low‐fertilizer regime (–26.0%). Thus, charcoal could be a valuable tool for reducing methane emissions associated with intensely fertilized flooded rice, without significantly affecting grain yields.
Integrating Muslim Customer Perceived Value, Satisfaction, Loyalty and Retention in the Tourism Industry: An empirical study
Authors: Eid Riyad
Published: December 2013

In recent years, customer value has been the favorable theme for numerous tourism studies and reports. However, although Muslims make up one of the largest tourist markets in the world, perceived value of tourism offering oriented toward this market has not been clearly defined. Furthermore, there is a lack of systematic empirical evidence regarding the effects of Muslim Customer Perceived Value (MCPV) on consumer satisfaction, customer loyalty and customer retention. Therefore, the purpose of this paper is to identify the MCPV dimensions, to examine the interrelationships between MCPV, customer satisfaction, customer loyalty and Muslim customer retention, and to develop and test a conceptual model of the consequences of MCPV in the tourism industry. Moreover, 13 hypotheses were developed and tested using a sample of 221 Muslim tourists. Exploratory and confirmatory factor analysis were used to test the validity of the measures, while the structural equation modeling has been used in hypotheses testing. The strength of the relationship between the constructs indicates that features of the suggested MCPV model are crucial to achieving Muslim customer retention in the tourism industry. Findings also suggest that the availability of the suggested Islamic attributes value, along with conventional value dimensions, could satisfy Muslim tourists when they buy a tourism package. Copyright © 2013 John Wiley & Sons, Ltd.
Optimization of sol–gel coating on the surface of aluminum alloy powder for corrosion protection in the condition of ultrasonic radiation
Authors: Liang B. , Wang G. D. , Zhang B. Y. , Zhang X. M.
Published: December 2013

In order to improve the corrosion resistance of an aluminum alloy powder (aluminum–copper–iron), a traditional sol–gel process (tetraethoxysilane [TEOS] was used as the precursor) was carried out in accordance with orthogonal experiments (L9(34)) in the first step. Solvent, reaction temperature, molar concentration of TEOS, and molar concentration of water were selected as the controllable factors. The optimum condition was obtained by means of the orthogonal analysis. In the second step, the encapsulation process was carried out under ultrasonic radiation based on the optimal reaction condition obtained from the traditional sol–gel process. We also studied the effects of ultrasonic power and radiation time on the encapsulation process. Finally, the corrosion inhibition factor of the encapsulated powder was reaching up to 99.5% in the hydrochloric acid (1 mol/L) solution. And the mean particle size of encapsulated powder was only 5.9% larger than that of the unencapsulated powder. Combined with the FTIR, XRD, DLS, SEM, and EDS analyses, it was concluded that an extremely thin layer had encapsulated on the aluminum alloy powder.
Effect of DyF3 on the corrosion behavior of hot‐pressed Nd–Fe–B permanent magnets
Authors: Sueptitz R. , Sawatzki S. , Moore M. , Uhlemann M. , Gutfleisch O. , Gebert A.
Published: December 2013

The grain boundary diffusion process (GBDP) with DyF3 is a promising method to obtain excellent magnetic properties in Nd–Fe–B permanent magnets. Compared to conventionally prepared (Dy,Nd)–Fe–B magnets the overall content of the precious heavy rare earth Dy is reduced. Thus, the GBDP with DyF3 is highly attractive to cut down costs and save resources. However, it is not well known how the addition of DyF3 affects the corrosion resistance of Nd–Fe–B permanent magnets. In this work, the anodic polarization behavior of hot‐pressed Nd–Fe–B magnets with and without DyF3 additions was investigated in electrolytes of different pH values. The results were compared with measurements on a commercially sintered Nd–Fe–B permanent magnet. In the polarization studies the only observed significant impact of DyF3 additions is an increased passive current density in alkaline media. The pitting susceptibility in NaOH solutions containing chloride ions is not affected by DyF3. Also in contrast to expectations, first free corrosion studies indicated no significant impact of the DyF3 additions on the dissolution rate.
Effect of SO2 on oxidation of metallic materials in CO2/H2O‐rich gases relevant to oxyfuel environments
Authors: Huczkowski P. , Olszewski T. , Schiek M. , Lutz B. , Holcomb G.R. , Shemet V. , Nowak W. , Meier G.H. , Singheiser L. , Quadakkers W.J.
Published: December 2013

In an oxyfuel plant, heat exchanging metallic components will be exposed to a flue gas that contains substantially higher contents of CO2, water vapor, and SO2 than conventional flue gases. In the present study, the oxidation behavior of the martensitic steel P92 was studied in CO2‐ and/or H2O‐rich gas mixtures with and without addition of SO2. For this purpose, the corrosion of P92 at 550 °C up to 1000 h in Ar–H2O–SO2, Ar–CO2–SO2, Ar–CO2–O2–SO2 and simulated oxyfuel gas (Ar–CO2–H2O–O2–SO2) was compared with the behavior in selected SO2‐free gases. The oxidation kinetics were estimated by a number of methods such as optical microscopy, scanning electron microscopy with energy and wave length dispersive X‐ray analysis, glow discharge optical emission spectroscopy, X‐ray diffraction as well as transmission electron microscopy.

The experimental results revealed that the effect of SO2 addition on the materials behavior substantially differed, depending on the prevailing base gas atmosphere. The various types of corrosion attack affected by SO2 could not be explained by solely comparing equilibrium activities of the gas atmospheres with thermodynamic stabilities of possible corrosion products. The results were found to be strongly affected by relative rates of reactions of the various gas species occurring within the frequently porous corrosion scales as well as at the scale/gas‐ and scale/alloy interfaces. Whereas SO2 addition to Ar–CO2 resulted in formation of an external mixed oxide/sulfide layer, the presence of SO2 in oxyfuel gas and in Ar–H2O–SO2 resulted in Fe‐sulfide formation near the interface between inner and outer oxide layer as well as Cr‐sulfide formation in the alloy. In the latter gases, the presence of SO2 seemed to have no dramatic effect on oxide scale growth rates.
What did we learn on the reactive element effect in chromia scale since Pfeil's patent?
Authors: Chevalier S.
Published: December 2013

Materials able to form protective chromia, Cr2O3, are most of time good candidates to be used at high temperatures in oxidizing atmospheres. Minor element additions are necessary to increase their mechanical or chemical properties. Among them, the reactive elements (RE) are highly efficient to improve the high temperature oxidation behavior of alloys. Their addition in small quantity is enough to greatly decrease the oxidation rates, but above all to drastically increase the oxide scale adherence to the base materials. That was the key point of what observed Pfeil 75 years ago. Since that date, many results have been published, many theories have been proposed, and many discussions have been engaged. Until now, the reasons why RE are so efficient are not fully understood, several hypotheses have been proposed in order to explain their beneficial effect on the oxide scale formation. According to the large amounts of published papers on this topic, there is probably no single theory envisageable to explain their role, whatever their nature, the tested materials and then the native oxide scale, as well as the nature of the oxidizing atmosphere. The decrease of the oxidation rate and the improvement of the oxide layer adherence are the final results due to RE additions. Generally, RE additions favor the nucleation and the growth of scales. They decrease the oxide grain size, and consequently could change scale plasticity and creep, which can modify the growth and/or thermal stresses generated within the scale during its growth or its cooling to room temperature. They prevent the detrimental sulfur effect and suppress dislocation climb in the metal and, then, limit cation transport (poisoned interface model). 75th Pfeil's patent anniversary seems good to make a pause in order to analyze what we really understood on the reactive element effect in chromia‐forming materials.
Performance of marine and offshore paint systems: Correlation of accelerated corrosion tests and field exposure on operating ships
Authors: LeBozec N. , Thierry D. , Le Calvé P. , Favennec C. , Pautasso J.‐P. , Hubert C.
Published: December 2013

Corrosion resistance is an important property requirement for marine paint systems used in naval industry such as for ship's topsides and superstructures, which obliges testing the coating performance in order to make a durable selection of the paint systems. This can be achieved by performing laboratory accelerated corrosion tests recommended for C5M corrosivity class (in particular the standard neutral salt spray test ISO 9227 or the cyclic corrosion test ISO 20340‐Annex A) which give results in a rather short delay (up to 6 months) compared to field exposures in marine atmospheres (several years). It is however well known that these tests may not be fully representative of real ship environmental conditions.

The aims of the present study were thus to compare and estimate the correlation of various accelerated corrosion tests including standardized tests (ISO 9227, ISO 20340, ISO 16701) and newly developed test conditions to field exposures on worldwide operating ships (container carrier vessel and oceanographic ship) and on conventional static marine atmospheric sites (C5M). Fifteen different marine paint systems commonly used for offshore and naval application were selected for the study. From the results, the exposure conditions on the container vessel were the most aggressive ones compared to static exposures after 2 years. The best correlation to such field exposure was observed using the cyclic test ISO 16701 with a deviation inferior to 25%, an acceleration factor of 4 and comparable corrosion aspect. If all testing conditions involving NaCl 5 wt% (including ISO 20340) showed a superior acceleration factor (e.g., about 12), a larger deviation (50%) was however found indicating that these tests did not accelerate the corrosion degradation of the paint systems similarly to field exposures. In addition, conditions for an optimization of ISO 20340 annex A test were found.
Surface‐Initiated RAFT/MADIX Polymerization on Xanthate‐Coated Iron Oxide Nanoparticles
Authors: Wilczewska Agnieszka Z. , Markiewicz Karolina H.
Published: December 2013

A new strategy for the preparation of magnetite/silica/(co)polymer core/shell nanoparticles is described. The reversible addition‐fragmentation chain transfer/macromolecular design via interchange of xanthates (RAFT/MADIX) polymerization agent — xanthate/dithiocarbonate — is covalently anchored to the aminosilica‐coated iron oxide nanoparticles surface by its R‐group. Subsequently, polymerization and copolymerization of vinyl monomers on such synthesized structures are carried out. Fourier transform infrared (FTIR) spectroscopy, UV–vis spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), energy‐dispersive X‐ray (EDX) analysis, and transmission electron micro­scopy (TEM) are employed to confirm the grafting and study the chemical composition of the obtained structures.

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The Influence of RAFT on the Microstructure and the Mechanical Properties of Photopolymerized Poly(butyl acrylate) Networks
Authors: Henkel Rouven , Vana Philipp
Published: December 2013

Statistical networks of butyl acrylate and 1,4‐butanediol diacrylate are photopolymerized in bulk, both in the presence and absence of the RAFT agent EPHT. The amounts of crosslinker and RAFT agent are varied. The Young's moduli of the RAFT networks are always lower than those of conventionally obtained networks. With increasing amounts of RAFT agent, the Young's modulus decreases and the strain at break values increase, respectively. The network density, the apparent molar mass of the network chains and the swelling show significant differences between RAFT‐ and conventionally obtained networks. The degree of swelling and the amount of extractable polymer increase largely with the amount of RAFT agent. Kinetic DSC measurements show that the gel point is delayed with increasing amounts of RAFT agent. In addition, a rate retardation effect with increasing RAFT agent concentration is observed.

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PCLR: Phase‐constrained low‐rank model for compressive diffusion‐weighted MRI
Authors: Gao Hao , Li Longchuan , Zhang Kai , Zhou Weifeng , Hu Xiaoping
Published: December 2013

Purpose

This work develops a compressive sensing approach for diffusion‐weighted (DW) MRI.

Theory and Methods

A phase‐constrained low‐rank (PCLR) approach was developed using the image coherence across the DW directions for efficient compressive DW MRI, while accounting for drastic phase changes across the DW directions, possibly as a result of eddy current, and rigid and nonrigid motions. In PCLR, a low‐resolution phase estimation was used for removing phase inconsistency between DW directions. In our implementation, GRAPPA (generalized autocalibrating partial parallel acquisition) was incorporated for better phase estimation while allowing higher undersampling factor. An efficient and easy‐to‐implement image reconstruction algorithm, consisting mainly of partial Fourier update and singular value decomposition, was developed for solving PCLR.

Results

The error measures based on diffusion‐tensor‐derived metrics and tractography indicated that PCLR, with its joint reconstruction of all DW images using the image coherence, outperformed the frame‐independent reconstruction through zero‐padding FFT. Furthermore, using GRAPPA for phase estimation, PCLR readily achieved a four‐fold undersampling.

Conclusion

The PCLR is developed and demonstrated for compressive DW MRI. A four‐fold reduction in k‐space sampling could be readily achieved without substantial degradation of reconstructed images and diffusion tensor measures, making it possible to significantly reduce the data acquisition in DW MRI and/or improve spatial and angular resolutions. Magn Reson Med 72:1330–1341, 2014. © 2013 Wiley Periodicals, Inc.
An interactive branch‐and‐bound algorithm for bicriterion nonconvex/mixed integer programming
Authors: Aksoy Yasemin
Published: December 2013

Although there has been extensive research on interactive multiple objective decision making in the last two decades, there is still a need for specialized interactive algorithms that exploit the relatively simple structure of bicriterion programming problems. This article develops an interactive branch‐and‐bound algorithm for bicriterion nonconvex programming problems. The algorithm searches among only the set of nondominated solutions since one of them is a most preferred solution that maximizes the overall value function of the decision maker over the set of achievable solutions. The interactive branch‐and‐bound algorithm requires only pairwise preference comparisons from the decision maker. Based on the decision maker's responses, the algorithm reduces the set of nondominated solutions and terminates with his most preferred nondominated solution. Branching corresponds to dividing the subset of nondominated solutions considered at a node into two subsets. The incumbent solution is updated based on the preference of the decision maker between two nondominated solutions. Fathoming decisions are based on the decision maker's preference between the incumbent solution and the ideal solution of the node in consideration.
A two‐phase procedure for allotting geostationary orbital locations to communications satellites
Authors: Reilly Charles H. , Mount‐Campbell Clark A. , Mata Fernando , Walton Eric K. , Aebker Eric A. , Levis Curt A.
Published: December 2013

We consider the problem of allotting locations in the geostationary orbit to communication satellites, subject to angle of elevation and electromagnetic interference constraints. An optimization framework is used as a means of finding feasible allotment plans. Specifically, we present a two‐phase solution procedure for the satellite location problem (SLP). The objective in SLP is to allot geostationary orbital locations to satellites so as to minimize the sum of the absolute differences between the locations prescribed for the satellites and corresponding specified desired locations. We describe two heuristics, an ordering procedure and a k‐permutation algorithm, that are used in tandem to find solutions to SLP. Solutions to a worldwide example problem with 183 satellites serving 208 service areas are summarized.
Aircraft weapon budgeting
Authors: Goldberg Matthew S.
Published: December 2013

This article considers the problem of allocating a fixed budget among alternative air‐to‐ground weapons. The weapon‐budgeting problem is high‐dimensional, involving all feasible combinations of aircraft, weapons, and targets. The decision maker's utility function is defined over kills of the various target types, but it is unrealistic to expect him to write down the mathematical formula for this function. The article suggests two procedures for reducing the dimension of the maximization problem and operating without exact knowledge of the utility function. The first procedure uses successive linear approximations to generate the set of “efficient” or undominated weapon allocations. The second procedure applies separability restrictions to the utility function, thereby reducing the overall maximization problem to a sequence of low‐dimensional subproblems.
Joint determination of optimum variable and attribute target means
Authors: Arcelus F.J. , Rahim M.A.
Published: December 2013

This article considers the problem of joint control of attribute and variable quality characteristics of a given product. Items are acceptable if they meet the specifications for both types of quality characteristics at the same time. Otherwise, the items are sold as scrap at reduced prices. The objective is to determine simultaneously the target values for each characteristic so as to maximize the expected profit per item. Several item‐by‐item quality‐inspection plans are formulated on the basis of various inspection strategies. These strategies are defined in terms of whether the inspection is to be carried out simultaneously for both characteristics, or sequentially, or whether inspection for one of the characteristics is to be ignored. All these plans are shown to differ in terms of their profitability. However, they all yield equivalent quality standards. A numerical example is provided to illustrate the application of these models.
Sandwich approximation of univariate convex functions with an application to separable convex programming
Authors: Burkard Rainer E. , Hamacher Horst W. , Rote Günter
Published: December 2013

In this article an algorithm for computing upper and lower ϵ approximations of a (implicitly or explicitly) given convex function h defined on an interval of length T is developed. The approximations can be obtained under weak assumptions on h (in particular, no differentiability), and the error decreases quadratically with the number of iterations. To reach an absolute accuracy of ϵ the number of iterations is bounded by

magnified image

, where D is the total increase in slope of h. As an application we discuss separable convex programs.
Isentropic primitive equations for the moist troposphere
Authors: Lee Shao‐Yi , Koh Tieh‐Yong
Published: December 2013

Despite the knowledge that the potential temperature of an air parcel has a dependence on its water vapour content, potential temperature is often still calculated as if the parcel were dry, assuming that this moisture dependence is negligible. We show that such a dry potential temperature approximation is not suitable for tropical regions. Moisture gradient terms are seen in the isentropic primitive equations when Exner and Montgomery functions are generalised with moist specific heat capacities, forming a contribution to the horizontal momentum tendency comparable to that by the Montgomery function. This reflects how local horizontal gradients in potential temperature created by inhomogeneous water vapour distribution are relatively significant compared to gradients created by inhomogeneous temperature, in a large‐scale background of weak horizontal temperature gradient. In such an environment, water plays an active role in tropical atmospheric dynamics without the uptake or release of latent heat during phase changes. Hence, we suggest that the tropical troposphere is a place where the atmosphere can behave dynamically as a binary‐component fluid at local and regional scales.
House of Reliability Costs: Developing Reliability Program Activities
Authors: Dror Shuki
Published: December 2013

Reliability is an important factor in the management, planning, and design of an engineering product. In order to meet the customer's requirements and achieve desired reliability level, different types of activities should be performed by the system developer/manufacturer. These activities have to be listed in corresponding reliability program and include: inspection, spare parts storage/providing, failure analysis, etc. On one hand, each activity from reliability program list requires some cost for its realization. On the other hand, when any activity was not performed, we should expect some losses because of system's failures. This paper presents an innovative method that enables a company to determine its vital activities in reliability program. The method is based on a House of Reliability Costs for translating the system's failure costs into relative importance of corresponding activities listed in the reliability program. A Mean Square Error (MSE) criterion supports the selection of vital reliability program activities. It divides a set of activities in reliability program into two groups: vital few (activities in reliability program) and trivial many. The partition minimizes the overall MSE and so, delineates two homogeneous groups. A case study is presented to illustrate the application of the developed methodology in a warfare system. The vital reliability program activities – treatment routine and spare parts storage – were found to be the best activities for reducing the costs of the warfare failures. Copyright © 2013 John Wiley & Sons, Ltd.
Behavior‐based botnet detection in parallel
Authors: Wang Kuochen , Huang Chun‐Ying , Tsai Li‐Yang , Lin Ying‐Dar
Published: December 2013

Botnet has become one major Internet security issue in recent years. Although signature‐based solutions are accurate, it is not possible to detect bot variants in real‐time. In this paper, we propose behavior‐based botnet detection in parallel (BBDP). BBDP adopts a fuzzy pattern recognition approach to detect bots. It detects a bot based on anomaly behavior in domain name service (DNS) queries and transmission control protocol (TCP) requests. With the design objectives of being efficient and accurate, a bot is detected using the proposed five‐stage process, including: (i) traffic reduction, which shrinks an input trace by deleting unnecessary packets; (ii) feature extraction, which extracts features from a shrunk trace; (iii) data partitioning, which divides features into smaller pieces; (iv) DNS detection phase, which detects bots based on DNS features; and (v) TCP detection phase, which detects bots based on TCP features. The detection phases, which consume approximately 90% of the total detection time, can be dispatched to multiple servers in parallel and make detection in real‐time. The large scale experiments with the Windows Azure cloud service show that BBDP achieves a high true positive rate (95%+) and a low false positive rate ( ∼ 3%). Meanwhile, experiments also show that the performance of BBDP can scale up linearly with the number of servers used to detect bots. Copyright © 2013 John Wiley & Sons, Ltd.
Symmetric key image encryption using chaotic Rossler system
Authors: Mandal Mrinal K. , Kar Madhumita , Singh Sandesh K. , Barnwal Vivek K.
Published: December 2013

In this article, an algorithm for encryption of digital image based on chaos theory is proposed. This encryption algorithm includes two main operations of image element shuffling and pixel replacement. The analysis of cryptographic strength (resistance attack) has been performed to confirm the fact. The results of several experimental tests, such as key space analysis, key sensitivity analysis, and statistical analysis, show that the proposed algorithm for image cryptosystems provides an efficient and secure way for image encryption and the hacker cannot decrypt an encrypted image without original key. A comparison in terms of correlation between the original and encrypted images, number of pixels change rate, unified average changing intensity, and mean absolute error is performed, which proves that the plain image is very different from the encrypted one. We have also performed fixed point analysis to know how many pixels remain fixed after pixel shuffling operation. Copyright © 2013 John Wiley & Sons, Ltd.
Metrics for covariate balance in cohort studies of causal effects
Authors: Franklin Jessica M. , Rassen Jeremy A. , Ackermann Diana , Bartels Dorothee B. , Schneeweiss Sebastian
Published: December 2013

Inferring causation from non‐randomized studies of exposure requires that exposure groups can be balanced with respect to prognostic factors for the outcome. Although there is broad agreement in the literature that balance should be checked, there is confusion regarding the appropriate metric. We present a simulation study that compares several balance metrics with respect to the strength of their association with bias in estimation of the effect of a binary exposure on a binary, count, or continuous outcome. The simulations utilize matching on the propensity score with successively decreasing calipers to produce datasets with varying covariate balance. We propose the post‐matchingC‐statistic as a balance metric and found that it had consistently strong associations with estimation bias, even when the propensity score model was misspecified, as long as the propensity score was estimated with sufficient study size. This metric, along with the average standardized difference and the general weighted difference, outperformed all other metrics considered in association with bias, including the unstandardized absolute difference, Kolmogorov–Smirnov and Lévy distances, overlapping coefficient, Mahalanobis balance, andL1metrics. Of the best‐performing metrics, theC‐statistic and general weighted difference also have the advantage that they automatically evaluate balance on all covariates simultaneously and can easily incorporate balance on interactions among covariates. Therefore, when combined with the usual practice of comparing individual covariate means and standard deviations across exposure groups, these metrics may provide useful summaries of the observed covariate imbalance. Copyright © 2013 John Wiley & Sons, Ltd.
Words, Words Everywhere, But Which Ones Do We Teach?
Authors: Graves Michael F. , Baumann James F. , Blachowicz Camille L. Z. , Manyak Patrick , Bates Ann , Cieply Char , Davis Jeni R. , Von Gunten Heather
Published: December 2013

This article highlights the challenging task teachers face in selecting vocabulary to teach. First, we briefly discuss three features of the English lexicon that are crucial to keep in mind when selecting vocabulary for instruction and three approaches that have been suggested. Then, we present a theoretically based approach called Selecting Words for Instruction from Texts (SWIT) that we developed and implemented in a vocabulary instruction research project. SWIT enables teachers to identify optimal words for instruction within three different categories (Essential, Valuable, Accessible, and Imported) and determine whether to provide Powerful Vocabulary Instruction, provide Brief Word Explanations, or guide students to Infer Meanings using context and morphology. Following that, we present detailed examples illustrating how teachers can use SWIT to identify and teach key vocabulary from a narrative text and from an informational text. The article ends with an appendix describing the research project in which we developed SWIT.