bluuebunny/crossref_metadata_2025 huggingface dataset:
Stagnation of treatment times over a decade: results of a pooled analysis from the MERCI registry, MERCI, TREVO, and TREVO 2 trials
Authors: Gupta Rishi , Xiang Bin , Ge Sijian , Sun Chung-Huan J , Yoo Albert J , Mehta Brijesh P
Published: March 2015

Background

There has been a growing interest in improving systems of care for the endovascular treatment of acute ischemic stroke. We analyzed data from previous registries and studies to determine if there has been an improvement in times to reperfusion with increasing experience.

Methods

We analyzed the pooled data from the Multi Mechanical Embolus Removal in Cerebral Ischemia (MERCI), MERCI Registry and Thrombectomy Revascularization of Large Vessel Occlusions (TREVO), and TREVO 2 trials and assessed times from last known normal to puncture, from hospital arrival to puncture, and procedure duration by year to determine if there has been a reduction in times. Demographic, radiographic, and clinical information were also assessed in a multivariate regression analysis to determine the predictors of good outcomes defined as a modified Rankin Scale score of 0–2 at 3 months.

Results

1248 patients of mean age 68±14 years and median NIH Stroke Scale score 18 were analyzed from 2001 to 2011. Procedure times showed a significant improvement while last known normal to puncture times remained static. In multivariate logistic regression analysis, longer last known normal to puncture time and longer procedure duration were associated with a decreased chance of a good outcome (OR 0.84, 95% CI 0.76 to 0.92, p=0.0004 and OR 0.75, 95% CI 0.61 to 0.91, p=0.0040, respectively).

Conclusions

Despite a reduction in procedure times, there has not been a corresponding improvement in overall last known normal to puncture times over a 10-year period. The current study shows that there are many opportunities to create more efficient endovascular stroke systems of care in trials.
Women who take n-3 long-chain polyunsaturated fatty acid supplements during pregnancy and lactation meet the recommended intake
Authors: Jia Xiaoming , Pakseresht Mohammadreza , Wattar Nour , Wildgrube Jamie , Sontag Stephanie , Andrews Murphy , Subhan Fatheema Begum , McCargar Linda , Field Catherine J. ,   the APrON study team
Published: March 2015

The aim of the current study was to estimate total intake and dietary sources of eicosapentaenoic acid (EPA), docosapentanoic (DPA), and docosahexaenoic acid (DHA) and compare DHA intakes with the recommended intakes in a cohort of pregnant and lactating women. Twenty-four–hour dietary recalls and supplement intake questionnaires were collected from 600 women in the Alberta Pregnancy Outcomes and Nutrition (APrON) cohort at each trimester of pregnancy and 3 months postpartum. Dietary intake was estimated in 2 ways: by using a commercial software program and by using a database created for APrON. Only 27% of women during pregnancy and 25% at 3 months postpartum met the current European Union (EU) consensus recommendation for DHA. Seafood, fish, and seaweed products contributed to 79% of overall n-3 long-chain polyunsaturated fatty acids intake from foods, with the majority from salmon. The estimated intake of DHA and EPA was similar between databases, but the estimated DPA intake was 20%–30% higher using the comprehensive database built for this study. Women who took a supplement containing DHA were 10.6 and 11.1 times more likely to meet the current EU consensus recommendation for pregnancy (95% confidence interval (CI): 6.952–16.07; P < 0.001) and postpartum (95% CI: 6.803–18.14; P < 0.001), respectively. Our results suggest that the majority of women in the cohort were not meeting the EU recommendation for DHA during pregnancy and lactation, but taking a supplement significantly improved the likelihood that they would meet recommendations.
Effect of environmental conditions on juvenile recruitment of alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis) in fresh water: a coastwide perspective
Authors: Tommasi Désirée , Nye Janet , Stock Charles , Hare Jonathan A. , Alexander Michael , Drew Katie
Published: March 2015

The abundance of alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis) has declined throughout their range, and there are increasing concerns about their conservation status. Because of their diadromous life history, variability in rates of survival in fresh water can affect overall recruitment. The objective of our study was to assess how river temperature and flow influence young of the year (YOY) river herring recruitment in the Northeast US. Observations of adult and juvenile fish in five rivers were used to construct spawner–YOY recruits models; these rivers were chosen because of the length of the time series (>15 years) and the paired observations of spawners and juveniles. An environmentally explicit stock–recruitment model explained a substantial fraction (41% to 80%) of the variance in YOY abundance, depending on river system. Our approach allowed for a preliminary discussion of potential mechanisms, which need to be further substantiated by focused field and laboratory studies. Early summer river flow and river temperature had the greatest influence, indicating the importance of conditions in nursery habitats. In certain systems, spring or fall conditions were also important determinants of survival, suggesting additional effects of the environment on spawning of adults and juvenile egress from freshwater nursery habitats.
Theoretical study of the structures, stabilities, and electronic properties of Na 2+ Xen (n = 1–6) clusters
Authors: Ghanmi Chedli , Bouhalleb Mefteh , Saidi Sameh , Berriche Hamid
Published: March 2015

The structures and stabilities of [Formula: see text]Xen (n =1–6) clusters are investigated using an accurate ab initio approach and an analytic potential form for the Na+–Xe and Xe–Xe interactions. The potential energy surfaces of the [Formula: see text](X2[Formula: see text])–Xen (n = 1–6) clusters are performed for a fixed distance of [Formula: see text](X2[Formula: see text]) in its equilibrium distance. For n = 1, the potential energy surfaces have been computed for an extensive range of the remaining two Jacobi coordinates, R and γ. In addition, we have determined the potential energy surfaces of 15 isomers of [Formula: see text](X2[Formula: see text])–Xen (n = 1–6). The potential energy surfaces are used to extract spectroscopic information on the stability of the [Formula: see text](X2[Formula: see text])Xen (n = 1–6) clusters. For each n, the stability of the different isomers is examined by comparing their potential energy surfaces. We find that the most stable isomers are C∞v(11), D∞h(21), C2v(31), D2h(41), C3v(51), and D3h(61). To our knowledge, there are no experimental and theoretical studies on the collision between the [Formula: see text](X2[Formula: see text]) alkali dimer and the xenon atom.
Size-dependent shell growth and survival in natural populations of the rock-dwelling land snail Chondrina clienta
Authors: Schmera Dénes , Baur Anette , Baur Bruno
Published: March 2015

Rock-dwelling land snails, feeding on algae and lichens that grow on stone surfaces, may influence the structure and function of these ecosystems. Yet, little is known about the life history of rock-dwelling snails. We performed a 30-month mark–release–resight study in four populations of Chondrina clienta (Westerlund, 1883) inhabiting vertical walls of abandoned limestone quarries on the Baltic island of Öland, Sweden, to assess growth rate and survival of juvenile snails and determine age at maturity. We marked 800 individuals ranging in shell height from 1.4 to 4.9 mm, released them in their original habitat, and remeasured their shell height at intervals of 6 months. Shell growth of juvenile C. clienta was affected by the site (quarry wall) and the size of the individual, being highest in medium-sized snails. Shell growth occurred during both summer and winter. Annual apparent survival rates of C. clienta were size-dependent and ranged from 58.6% to 96.3%. Sexual maturity was reached at an age of 5 years, which is later than in most large snail species. Our study extends current knowledge on life history of land snails to a rarely studied group dwelling on rock surfaces.
Estimates of antipodal sets in oriented real Grassmann manifolds
Authors: Tasaki Hiroyuki
Published: March 2015

We estimate the cardinalities of antipodal sets in oriented real Grassmann manifolds of low ranks. The author reduced the classification of antipodal sets in oriented real Grassmann manifolds to a certain combinatorial problem in a previous paper. So we can reduce estimates of the antipodal sets to those of certain combinatorial objects. The sequences of antipodal sets we obtained in previous papers show that the estimates we obtained in this paper are the best.
Harmonic maps from Riemann surfaces into complex Finsler manifolds
Authors: Nishikawa Seiki
Published: March 2015

Given a smooth map from a compact Riemann surface to a complex manifold equipped with a strongly pseudoconvex complex Finsler metric, we define the [Formula: see text]-energy of the map, whose absolute minimum is attained by a holomorphic map. A harmonic map is then defined to be a stationary map of the [Formula: see text]-energy functional. We prove that with each harmonic map is associated a holomorphic quadratic differential on the domain, which vanishes if the map is weakly conformal. Also, under the condition that the metric be weakly Kähler, we determine the second variation of the functional, and prove that any [Formula: see text]-energy minimizing harmonic map from the Riemann sphere to a weakly Kähler Finsler manifold of positive curvature is either holomorphic or anti-holomorphic.
On contact embeddings of contact manifolds in the odd dimensional Euclidean spaces
Authors: Kasuya Naohiko
Published: March 2015

We prove that a closed co-oriented contact (2m + 1)-manifold (M2m + 1, ξ) can be a contact submanifold of the standard contact structure on ℝ4m + 1, if it satisfies one of the following conditions: (1) m is odd (m ≥ 3) and H1(M2m + 1; ℤ) = 0, (2) m is even (m ≥ 4) and M2m + 1 is 2-connected, (3) m = 2 and M5 is simply-connected.
Numerical prediction on deposition of micro-particulate matter in turbulent channel flows
Authors: Wang Bing , Lin Jing
Published: March 2015

A direct numerical simulation of Navier–Stokes equation coupled to the Lagrangian tracking of individual particles was used to predict the dispersion of deposited micro-particulate matter in turbulent channel flows on the walls. The different interaction conditions between particles and walls were considered for particles with Stokes numbers ranging from 0.1 to 104. The particle deposition rates were predicted accurately because of the accurate calculation of turbulence and particle dispersion. It was found the interaction between the turbulent particles and the walls determined the re-entrainment mechanism of inertial particles away from the wall. The dispersion of deposition of particles were independent of the wall conditions in the partial diffusional and whole diffusion-impaction regime, consistent with a log–log law with particle Stokes number, which was found to be [Formula: see text]. The deposition rate decreased with decreasing adhesion of the wall in the inertia-moderated regime. The present results may be helpful for establishing and evaluating accurate prediction models of micro-particle deposition rates in various engineering applications.
Review of some important beam physics issues in electron–positron collider designs
Authors: Gao Jie
Published: March 2015

In this paper, we will give a brief review of some important beam physics in circular and linear electron–positron collider designs, covering beam–beam tune limits, longitudinal and transverse single bunch collective effects, electron cloud and space charge effects, dynamic aperture estimations, etc. The main feature of this review is that the corresponding beam physics treatments are coming from author's previous research works which are scattered in different scientific publications both for circular and linear colliders. With the progresses of future linear colliders, such as ILC, and future circular electron–positron colliders, such as CEPC, it is high time to review the key beam physics issues in the optimization designs of these two kinds of machines.
Quasi-normal modes and the area spectrum of a near extremal de Sitter black hole with conformally coupled scalar field
Authors: Fernando Sharmanthie
Published: March 2015

In this paper, we have studied a black hole in de Sitter space which has a conformally coupled scalar field in the background. This black hole is also known as the MTZ black hole. We have obtained exact values for the quasi-normal mode (QNM) frequencies under massless scalar field perturbations. We have demonstrated that when the black hole is near-extremal, that the wave equation for the massless scalar field simplifies to a Schrödinger type equation with the well-known Pöschl–Teller potential. We have also used sixth-order WKB approximation to compute QNM frequencies to compare with exact values obtained via the Pöschl–Teller method for comparison. As an application, we have obtained the area spectrum using modified Hods approach and show that it is equally spaced.
Effect of characterization of porous metal fiber media on sound absorption coefficient
Authors: Wang J. Z. , Ao Q. B. , Tang H. P. , Bao T. F.
Published: March 2015

Porous metal fiber media (PMFM) is a kind of advanced structural and functional material, and it has attracted a wide spread attention owing to excellent sound absorption performance. The sound absorption property of PMFM is mainly influenced by the fiber diameter, the average pore size and thickness of PMFM. In the paper, three stainless steel fibers with the diameters (∅) of 8, 12 and 20 μm were used to make PMFM with the average pore sizes of 10, 20, 30 and 40 μm and the thicknesses of 1, 2 and 3 mm by air-laid and sintering processes. The sound absorption coefficients of PMFM were tested in impedance tube using two-microphone transfer-function method according to ISO 10534-2 and ASTM E1050-98 international standards at room temperature. The results show that when the frequency ranges from 50 Hz to 6,400 Hz in material with the average pore size of 20 μm and the thickness of 3 mm and the fiber diameter of ∅8 μm, the average sound absorption coefficient is the highest.
Toward a mathematical theory of Keller–Segel models of pattern formation in biological tissues
Authors: Bellomo N. , Bellouquid A. , Tao Y. , Winkler M.
Published: March 2015

This paper proposes a survey and critical analysis focused on a variety of chemotaxis models in biology, namely the classical Keller–Segel model and its subsequent modifications, which, in several cases, have been developed to obtain models that prevent the non-physical blow up of solutions. The presentation is organized in three parts. The first part focuses on a survey of some sample models, namely the original model and some of its developments, such as flux limited models, or models derived according to similar concepts. The second part is devoted to the qualitative analysis of analytic problems, such as the existence of solutions, blow-up and asymptotic behavior. The third part deals with the derivation of macroscopic models from the underlying description, delivered by means of kinetic theory methods. This approach leads to the derivation of classical models as well as that of new models, which might deserve attention as far as the related analytic problems are concerned. Finally, an overview of the entire contents leads to suggestions for future research activities.
On dilatation factors of braids on three strands
Authors: Aguilera Marta
Published: March 2015

In this work we present a direct connection between Garside normal forms in the braid group B3 and their associated matrices in SL 2(ℕ) coming from the Nielsen–Thurston theory. As a consequence, we can give an upper and a lower bound for the dilatation factor of a rigid pseudo-Anosov three-strands braid with canonical length ℓ.
Connected sum of representations of knot groups
Authors: Cho Jinseok
Published: March 2015

When two boundary-parabolic representations of knot groups are given, we introduce the connected sum of these representations and show several natural properties including the unique factorization property. Furthermore, the complex volume of the connected sum is the sum of each complex volumes modulo iπ2 and the twisted Alexander polynomial of the connected sum is the product of each polynomials with normalization.
Some Useful Approximations for the Availability Function
Authors: Arunachalam Viswanathan , Calvache Alvaro , Tansu Ayşe
Published: March 2015

Availability function which forms an important part of reliability analysis is expressed in terms of an integral equation. The analytical solution of such an equation is possible only in very simple cases and hence approximations are the only tools available; very few such approximations are available in the literature. This paper proposes three useful approximations, two of which are based only on the first few moments of the underlying distributions and do not require their functional forms. The third approximation uses the Riemannian sum to approximate the integral equation. Numerical illustrations based on test cases are provided to show the efficacy of the approximations. As an application, the problem of an opportunistic channel access scheme in a communication network is used to test the approximations.
Free Vibration Analysis of Rotating Axially Functionally Graded Tapered Timoshenko Beams
Authors: Fang Jian-Shi , Zhou Ding
Published: March 2015

The free vibration of rotating tapered Timoshenko beams (TBs) made of the axially functionally graded materials (FGMs) is studied. The Chebyshev polynomials multiplied by the boundary functions are selected as the admissible functions in the Ritz minimization procedure, which is called the Chebyshev–Ritz method. As such, the geometric boundary conditions are satisfied, while the numerical robustness is guaranteed through use of the Chebyshev polynomials. The Ritz approach provides an upper bound of the exact frequencies. The effectiveness of the method is confirmed in the convergence and comparison studies. The effects of hub radius ratio, rotational speed ratio, taper ratios, rotary inertia and material gradient on the natural frequencies of the TBs for six different sets of boundary conditions are studied in detail.
Planarity of the intersection graph of subgroups of a finite group
Authors: Ahmadi Hadi , Taeri Bijan
Published: March 2015

For a nontrivial finite group [Formula: see text] different from a cyclic group of prime order, the intersection graph [Formula: see text] of [Formula: see text] is the simple undirected graph whose vertices are the nontrivial proper subgroups of [Formula: see text] and two vertices are joined by an edge if and only if they have a nontrivial intersection. In this paper we characterize all finite groups with planar intersection graphs. It turns out that few solvable groups have planar intersection graphs. Also we classify finite groups whose intersection graphs are bipartite, triangle free and forests.
Localization at countably infinitely many prime ideals and applications
Authors: Bahmanpour Kamal , Quy Pham Hung
Published: March 2015

In this paper we present a technical lemma about localization at countably infinitely many prime ideals. We apply this lemma to get many results about the finiteness of associated prime ideals of local cohomology modules.
PBW deformations of quantum symmetric algebras and their group extensions
Authors: Shroff Piyush , Witherspoon Sarah
Published: March 2015

We examine PBW deformations of finite group extensions of quantum symmetric algebras, in particular the quantum Drinfeld orbifold algebras defined by the first author. We give a homological interpretation, in terms of Gerstenhaber brackets, of the necessary and sufficient conditions on parameter functions to define a quantum Drinfeld orbifold algebra, thus clarifying the conditions. In case the acting group is trivial, we determine conditions under which such a PBW deformation is a generalized enveloping algebra of a color Lie algebra; our PBW deformations include these algebras as a special case.
Eventually linear partially complete resolutions over a local ring with 𝔪4 = 0
Authors: Beck Kristen A.
Published: March 2015

We classify the Hilbert polynomial of a local ring [Formula: see text] satisfying [Formula: see text] which admits a doubly-infinite eventually linear resolution [Formula: see text] which is “partially” complete — that is, for which [Formula: see text] vanishes for all [Formula: see text]. As a corollary to our main result, we show that an [Formula: see text] local ring can admit certain classes of asymmetric partially complete resolutions only if its Hilbert polynomial is symmetric. Moreover, we show that the Betti sequence associated to an eventually linear partially complete resolution over an [Formula: see text] local ring cannot be periodic of period two or three.
REFLECTIONS ON IMPACT ASSESSMENT RESEARCH SCHOLARSHIP FROM EDITOR AND ACADEMIC PERSPECTIVES
Authors: MORRISON-SAUNDERS ANGUS , RETIEF FRANCOIS
Published: March 2015

Reflections on impact assessment research scholarship are presented drawn from our experiences as journal editors and academics with respect to the nature of impact assessment research and the quality of impact assessment research writing. We support the call for more empirical impact assessment research studies, especially large and longer-term studies. While the international field of impact assessment research is healthy overall, we would like to see better international and multi-disciplinary collaboration. We also urge careful attention be given by impact assessment research writers to having clear aims, robust methods accounts and to write rigorously and insightfully for the international impact assessment journal readership.
GETTING EA RESEARCH OUT OF THE COMFORT ZONE: CRITICAL REFLECTIONS FROM THE NETHERLANDS
Authors: RUNHAAR HENS , ARTS JOS
Published: March 2015

This paper is a "statement" for the March special issue of JEAPM on "Impact Assessment Research: Achievements, Gaps and Future Directions".
Synthesis and Characterization of Novel AlF3 Cubes
Authors: Xue Maoquan , Li Changsheng
Published: March 2015

In this paper, regularly shaped AlF 3 particles with cubic structure were successfully synthesized via a solvothermal route. The as-prepared products were characterized by X-ray powder diffraction (XRD), energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results indicated that reaction temperature and time have significant effects on the morphology of the as-prepared products. A possible formation process has also been investigated on the basis of a series of XRD and SEM studies of the product obtained at different conditions. This well-controlled synthesis approach may be extended to fabricate other metal fluoride materials.
Pyrochlore and columbite-tantalite as indicator minerals for specialty metal deposits
Authors: Mackay D.A.R. , Simandl G.J.
Published: March 2015

Pyrochlore supergroup and columbite-tantalite series minerals can be used as indicators for specialty metal deposits. Their mineral chemistry can be used to target specific specialty metal deposit-types and provide a vector towards mineralisation. A ternary Nb-Ti-Ta discrimination diagram for the pyrochlore supergroup shows that minerals from carbonatites and related deposits occupy the pyrochlore field and extend slightly into the betafite and microlite fields (>35% Nb, <65% Ti, and <45% Ta). Those from peralkaline complexes define a narrow zone paralleling the Nb-Ti join (>40% Nb, <60% Ti, and <10% Ta). Pyrochlore supergroup minerals from Li-Cs-Ta enriched (LCT) pegmatites occupy the microlite field (<90% Nb, ≤40% Ti, and > 15% Ta) whereas those from peraluminous granites plot in the microlite field along the Nb-Ta join, extending slightly into the pyrochlore field (<65% Nb, <10% Ti, and >35% Ta) on the Nb-Ti-Ta ternary diagram. The discrimination diagram for pyrochlore supergroup minerals is based on 349 new electron microprobe analyses from British Columbia and Québec, Canada, combined with 879 published analyses from 50 deposits worldwide.

A columbite-tantalite series discrimination quadrilateral indicates that minerals from carbonatites and related deposits are Nb-rich, with Mn/(Mn+Fe) and Ta/(Ta+Nb) atomic ratios ≤ 0.25 and ≤ 0.20, respectively. Columbite from peralkaline complexes plot along the FeNb
2
O
6
–MnNb
2
O
6
join of the quadrilateral and have Mn/(Mn+Fe) ratios of ≤ 0.65 and Ta/(Ta+Nb) ratios of ≤ 0.15. Fe-Nb-rich varieties within this zone slightly overlap with those from carbonatites. Columbite-tantalite series minerals from Li-Cs-Ta (LCT) pegmatites and peraluminous granites are not well constrained but do slightly overlap with columbite-(Fe) from carbonatites. A minor overlap exists between the fields from carbonatites, peralkaline complexes, LCT pegmatites, and peraluminous granites near the columbite-(Fe) corner of the quadrilateral. The discrimination diagram for columbite-tantalite series minerals is based on 153 new electron microprobe analyses from British Columbia combined with over 2500 analyses complied from the literature. Combining the two discrimination diagrams presented here enhances their effectiveness to explore for specialty metal deposits.
Minimizing Deterministic Lattice Automata
Authors: Halamish Shulamit , Kupferman Orna
Published: March 2015

Traditional automata accept or reject their input and are therefore Boolean. In contrast, weighted automata map each word to a value from a semiring over a large domain. The special case of
lattice automata
, in which the semiring is a finite lattice, has interesting theoretical properties as well as applications in formal methods. A
minimal deterministic automaton
captures the combinatorial nature and complexity of a formal language. Deterministic automata are used in runtime monitoring, pattern recognition, and modeling systems. Thus, the minimization problem for deterministic automata is of great interest, both theoretically and in practice.

For deterministic traditional automata on finite words, a minimization algorithm, based on the Myhill-Nerode right congruence on the set of words, generates in polynomial time a canonical minimal deterministic automaton. A polynomial algorithm is known also for deterministic weighted automata over the tropical semiring. For general deterministic weighted automata, the problem of minimization is open. In this article, we study minimization of deterministic lattice automata. We show that it is impossible to define a right congruence in the context of lattices, and that no canonical minimal automaton exists. Consequently, the minimization problem is much more complicated, and we prove that it is NP-complete. As good news, we show that while right congruence fails already for finite lattices that are fully ordered, for this setting we are able to combine a finite number of right congruences and generate a minimal deterministic automaton in polynomial time.
Size Bounds for Factorised Representations of Query Results
Authors: Olteanu Dan , Závodný Jakub
Published: March 2015

We study two succinct representation systems for relational data based on relational algebra expressions with unions, Cartesian products, and singleton relations: f-representations, which employ algebraic factorisation using distributivity of product over union, and d-representations, which are f-representations where further succinctness is brought by explicit sharing of repeated subexpressions.

In particular we study such representations for results of conjunctive queries. We derive tight asymptotic bounds for representation sizes and present algorithms to compute representations within these bounds. We compare the succinctness of f-representations and d-representations for results of equi-join queries, and relate them to fractional edge covers and fractional hypertree decompositions of the query hypergraph.

Recent work showed that f-representations can significantly boost the performance of query evaluation in centralised and distributed settings and of machine learning tasks.
Self-Tuning Batching with DVFS for Performance Improvement and Energy Efficiency in Internet Servers
Authors: Cheng Dazhao , Guo Yanfei , Jiang Changjun , Zhou Xiaobo
Published: March 2015

Performance improvement and energy efficiency are two important goals in provisioning Internet services in datacenter servers. In this article, we propose and develop a self-tuning request batching mechanism to simultaneously achieve the two correlated goals. The batching mechanism increases the cache hit rate at the front-tier Web server, which provides the opportunity to improve an application’s performance and the energy efficiency of the server system. The core of the batching mechanism is a novel and practical two-layer control system that adaptively adjusts the batching interval and frequency states of CPUs according to the service level agreement and the workload characteristics. The batching control adopts a self-tuning fuzzy model predictive control approach for application performance improvement. The power control dynamically adjusts the frequency of Central Processing Units (CPUs) with Dynamic Voltage and Frequency Scaling (DVFS) in response to workload fluctuations for energy efficiency. A coordinator between the two control loops achieves the desired performance and energy efficiency. We further extend the self-tuning batching with DVFS approach from a single-server system to a multiserver system. It relies on a MIMO expert fuzzy control to adjust the CPU frequencies of multiple servers and coordinate the frequency states of CPUs at different tiers. We implement the mechanism in a test bed. Experimental results demonstrate that the new approach significantly improves the application performance in terms of the system throughput and average response time. At the same time, the results also illustrate the mechanism can reduce the energy consumption of a single-server system by 13% and a multiserver system by 11%, respectively.
From Ant Trails to Pedestrian Dynamics
Authors: Schadschneider Andreas , Kirchner Ansgar , Nishinari Katsuhiro
Published: March 2015

This paper presents a model for the simulation of pedestrian dynamics inspired by the behaviour of ants in ant trails. Ants communicate by producing a pheromone that can be smelled by other ants. In this model, pedestrians produce a virtual pheromone that influences the motion of others. In this way all interactions are strictly local, and so even large crowds can be simulated very efficiently. Nevertheless, the model is able to reproduce the collective effects observed empirically, eg the formation of lanes in counterflow. As an application, we reproduce a surprising result found in experiments of evacuation from an aircraft.
Learning Algorithm for a Brachiating Robot
Authors: Kajima Hideki , Hasegawa Yasuhisa , Fukuda Toshio
Published: March 2015

This paper introduces a new concept of multi-locomotion robot inspired by an animal. The robot, ‘Gorilla Robot II’, can select the appropriate locomotion (from biped locomotion, quadruped locomotion and brachiation) according to an environment or task. We consider ‘brachiation’ to be one of the most dynamic of animal motions. To develop a brachiation controller, architecture of the hierarchical behaviour-based controller, which consists of behaviour controllers and behaviour coordinators, was used. To achieve better brachiation, an enhanced learning method for motion control, adjusting the timing of the behaviour coordination, is proposed. Finally, it is shown that the developed robot successfully performs two types of brachiation and continuous locomotion.
The Use of Degradable Nerve Conduits for Human Nerve Repair: A Review of the Literature
Authors: Meek M. F. , Jansen K. , Robinson P. H.
Published: March 2015

The management of peripheral nerve injury continues to be a major clinical challenge. The most widely used technique for bridging defects in peripheral nerves is the use of autologous nerve grafts. This technique, however, has some disadvantages. Many alternative experimental techniques have thus been developed, such as degradable nerve conduits. Degradable nerve guides have been extensively studied in animal experimental studies. However, the repair of human nerves by degradable nerve conduits has been limited to only a few clinical studies. In this paper, an overview of the available international published literature on degradable nerve conduits for bridging human peripheral nerve defects is presented for literature available until 2004. Also, the philosophy on the use of nerve guides and nerve grafts is given.
Optimization-Based Layout Design
Authors: Abdel-Malek K. , Mi Z. , Yang J. , Nebel K.
Published: March 2015

The layout problem is of importance to ergonomists, vehicle/cockpit packaging engineers, designers of manufacturing assembly lines, designers concerned with the placement of levers, knobs, controls, etc. in the reachable workspace of a human, and also to users of digital human modeling code, where digital prototyping has become a valuable tool. This paper proposes a hybrid optimization method (gradient-based optimization and simulated annealing) to obtain the layout design. We implemented the proposed algorithm for a project at Oral-B Laboratories, where a manufacturing cell involves an operator who handles three objects, some with the left hand, others with the right hand.
Compressive Loads on the Lumbar Spine During Lifting: 4D WATBAK versus Inverse Dynamics Calculations
Authors: Cole M. H. , Grimshaw P. N.
Published: March 2015

Numerous two- and three-dimensional biomechanical models exist for the purpose of assessing the stresses placed on the lumbar spine during the performance of a manual material handling task. More recently, researchers have utilised their knowledge to develop specific computer-based models that can be applied in an occupational setting; an example of which is 4D WATBAK. The model used by 4D WATBAK bases its predications on static calculations and it is assumed that these static loads reasonably depict the actual dynamic loads acting on the lumbar spine. Consequently, it was the purpose of this research to assess the agreement between the static predictions made by 4D WATBAK and those from a comparable dynamic model. Six individuals were asked to perform a series of five lifting tasks, which ranged from lifting 2.5 kg to 22.5 kg and were designed to replicate the lifting component of the Work Capacity Assessment Test used within Australia. A single perpendicularly placed video camera was used to film each performance in the sagittal plane. The resultant two-dimensional kinematic data were input into the 4D WATBAK software and a dynamic biomechanical model to quantify the compression forces acting at the L4/L5 intervertebral joint. Results of this study indicated that as the mass of the load increased from 2.5 kg to 22.5 kg, the static compression forces calculated by 4D WATBAK became increasingly less than those calculated using the dynamic model (mean difference ranged from 22.0% for 2.5 kg to 42.9% for 22.5 kg). This study suggested that, for research purposes, a validated three-dimensional dynamic model should be employed when a task becomes complex and when a more accurate indication of spinal compression or shear force is required. Additionally, although it is clear that 4D WATBAK is particularly suited to industrial applications, it is suggested that the limitations of such modelling tools be carefully considered when task-risk and employee safety are concerned.
Self-Tuning Insulin Adjustment Algorithm for Type 1 Diabetic Patients based on Multi-Doses Regime
Authors: Campos-Delgado D. U. , Femat R. , Hernández-Ordoñez M. , Gordillo-Moscoso A.
Published: March 2015

A self-tuning algorithm is presented for on-line insulin dosage adjustment in type 1 diabetic patients (chronic stage). The algorithm suggested does not need information of the patient insulin–glucose dynamics (model-free). Three doses are programmed daily, where a combination of two types of insulin: rapid/short and intermediate/long acting is injected into the patient through a subcutaneous route. The doses adaptation is performed by reducing the error in the blood glucose level from euglycemics. In this way, a total of five doses are tuned per day: three rapid/short and two intermediate/long, where there is large penalty to avoid hypoglycemic scenarios. Closed-loop simulation results are illustrated using a detailed nonlinear model of the subcutaneous insulin–glucose dynamics in a type 1 diabetic patient with meal intake.
Shape Restoration by Active Self-Assembly
Authors: Arbuckle D. , Requicha A. A. G.
Published: March 2015

Shape restoration is defined as the problem of constructing a desired, or goal, solid shape Sg by growing an initial solid Si, which is a subset of the goal but is otherwise unknown. This definition attempts to capture abstractly a situation that often arises in the physical world when a solid object loses its desired shape due to wear and tear, corrosion or other phenomena. For example, if the top of the femur becomes distorted, the hip joint no longer functions properly and may have to be replaced surgically. Growing it in place back to its original shape would be an attractive alternative to replacement. This paper presents a solution to the shape restoration problem by using autonomous assembly agents (robots) that self-assemble to fill the volume between Sg and Si. If the robots have very small dimension (micro or nano), the desired shape is approximated with high accuracy. The assembly agents initially execute a random walk. When two robots meet, they may exchange a small number of messages. The robot behavior is controlled by a finite state machine with a small number of states. Communication contact models chemical communication, which is likely to be the medium of choice for robots at the nanoscale, while small state and small messages are limitations that also are expected of nanorobots. Simulations presented here show that swarms of such robots organize themselves to achieve shape restoration by using distributed algorithms. This is one more example of an interesting geometric problem that can be solved by the Active Self-Assembly paradigm introduced in previous papers by the authors.
Bionics Solution to Learn the Arm Reaching with Collision Avoidance
Authors: Gorce P. , Bendahan P.
Published: March 2015

This article presents a learning model that simulates the control of an anthropomorphic arm kinematics motion. The objective is to reach and grasp a static prototypic object placed behind different kinds of obstacle in size and position. The network, composed of two generic neural network modules, learns to combine multi-modal arm-related information (trajectory parameters) as well as obstacle-related information (obstacle size and location). Our simulation was based on the notion of Via Point, which postulates that the motion planning that is divided into specific successive position of the arm. In order to determine these special points, an experimental protocol has been built and pertinent parameters have been integrated to the model. According to these studies, we propose an original method that takes into account the previous learning modules to determine the entire trajectory of the wrist in order to reach the same object placed behind two successive obstacles. The aim of this approach is to understand better the impact of experience in a task realisation and show that learning can be performed from previous initiation. Some results (applied to obstacle avoidance task) show the efficiency of the proposed method.
Issues Impairing the Success of Neural Implant Technology
Authors: Spiers A. , Warwick K. , Gasson M. , Ruiz V.
Published: March 2015

By monitoring signals from the central nervous system, humans can be provided with a novel extra channel of communication that can, for example, be used for the voluntary control of peripheral devices. Meanwhile, stimulation of neural tissue can bring about sensation such as touch, can facilitate feedback from external, potentially remote devices and even opens up the possibility of new sensory input for the individual to experience. The concept of successfully harnessing and stimulating nervous system activity is though something that can only be achieved through an appropriate interface. However, interfacing the nervous system by means of implant technology carries with it many problems and dangers. Further, results achieved may not be as expected or as they at first appear. This paper describes a comparative study investigating different implant types and procedures. It is aimed at highlighting potential problem areas and is intended to provide a useful reference explaining important tolerances and limits.
Electromyographic Pattern Analysis and Classification for a Robotic Prosthetic Arm
Authors: Erazo Macias M. José H. , Vega S. Alejandro
Published: March 2015

This paper deals with the statistical analysis and pattern classification of electromyographic signals from the biceps of a person with amputation below the humerus. Such signals collected from an amputation simulator are synergistically generated to produce discrete elbow movements. The purpose of this study is to utilise these signals to control an electrically driven prosthetic or orthotic elbow with minimum extra mental effort on the part of the subject. The results show very good separability of classes of movements when a learning pattern classification scheme is used, and a superposition of any composite motion to the three basic primitive motions—humeral rotation in and out, flexion and extension, and pronation and supination. Since no synergy was detected for the wrist movement, different inputs have to be provided for a grip. In addition, the method described is not limited by the location of the electrodes. For amputees with shorter stumps, synergistic signals could be obtained from the shoulder muscles. However, the presentation in this paper is limited to biceps signal classification only.
A Game Theoretic Approach to Swarm Robotics
Authors: Givigi S. N. , Schwartz H. M.
Published: March 2015

In this article, we discuss some techniques for achieving swarm intelligent robots through the use of traits of personality. Traits of personality are characteristics of each robot that, altogether, define the robot's behaviours. We discuss the use of evolutionary psychology to select a set of traits of personality that will evolve due to a learning process based on reinforcement learning. The use of Game Theory is introduced, and some simulations showing its potential are reported.
Towards an Artificial Phonological Loop: An Assistive Device for Working Memory and Attentional Control
Authors: Bogen D.
Published: March 2015

We describe the initial development of anartificial phonological loop(APL), a new technology to assist individuals with impairment of the working memory system. The phonological loop, along with the visuospatial sketchpad, is one of the two slave short-term memory subsystems that comprise working memory, a cognitive function closely associated with the control of attention. In the phonological loop, phonological (speech) information lasting for 1–2 second is maintained active by repetitive, subvocal (silent speech) rehearsal. Deficits in working memory, specifically in the phonological loop, occur in many disorders, including attention-deficit disorder and Alzheimer’s disease. In these disorders, it appears that the ability for phonological rehearsal is intact, but the regulation or triggering of the rehearsal process is inadequate, thus causing the contents of working memory to be lost. The purpose, then, of the APL is to facilitate the phonological loop by artificially extending the duration of phonological rehearsals. The APL mimics the natural phonological loop by providing audible vocal echoes to take the place of subvocal rehearsals. In this system, the user talks to him/herself in short (1–2 second) phrases; the device records these phrases, stores them in electronic memory, and then repeats— i.e.,echoes—the phrases multiple times over an extended period. Two versions of this device have been developed: the Echo-APL and the Rearticulation-APL. In the Echo-APL, only echoing is involved. In the Rearticulation-APL, however, the user re-vocalizes (rearticulates) the phrase in response to an audible cue. The device repeats the cue until it detects (hears) the re-vocalization. Future research and development of the APL will require extensive testing and careful evaluation of possibleecho-schedules: the predefined program controlling inter-echo time intervals and echo-amplitude (echo loudness). The APL essentially exteriorizes the silent phonological loop and makes it audible. It is a system that helps the user to “talk to him/herself” to keep ideas in mind.
Mechanical Responses and Physical Factors of the Fingertip Pulp
Authors: Sakai N. , Shimawaki S.
Published: March 2015

The images of the mechanical responses were analysed when the fingertip was pressed against a plateau plate, and the influence of the contact angle on the loading pressure and the mechanical responses was investigated. As a result, as the contact angle was smaller, the change ratios due to the loading pressure were significantly larger in the contact length, the contact width and the distortion of lateral-view area. These parameters were thought to be useful in clinical medicine as indices for the degrees of mechanical responses of the fingertip. The length of the central axis and the maximum width of the fingertip were inappropriate as the parameters to represent the mechanical responses of the fingertip. The maximum width of the fingertip scarcely changed. This does not reflect the compressibility of the fingertip, and the fingertip as a whole extended along the central axis and in the vertical direction, and the change was not reflected in the maximum width.
The Development of a Hybrid Underwater Micro Biped Robot
Authors: Guo S. , Okuda Y. , Zhang W. , Ye X. , Asaka K.
Published: March 2015

There has been a great demand, in the medical field and in industrial applications, for a novel micro biped robot with multiple degrees of freedom that can swim smoothly in water or in aqueous medium. The fish-like micro-robot studied is a type of miniature device that is installed with sensing and actuating elements. This article describes the new structure and motion mechanism of a hybrid type of underwater micro-robot using an ion-conducting polymer film (ICPF) actuator, and discusses the swimming and floating characteristics of the micro-robot in water, measured by changing the voltage frequency and the amplitude of the input voltage. Results indicate that the swimming speed of the proposed underwater micro-robot can be controlled by changing the frequency of the input voltage, and the direction (upward or downward) can be manipulated by changing the frequency of the electric current applied and the amplitude of the voltage.
Pivoting a Large Object: Whole-Body Manipulation by a Humanoid Robot
Authors: Yoshida E. , Blazevic P. , Hugel V. , Yokoi K. , Harada K.
Published: March 2015

In this article, we present a method of whole-body manipulation of large objects by a humanoid robot using a pivoting motion. Pivoting manipulation can be an alternative to pushing or lifting for more dexterous and stable operation, which is often used by humans to move large and bulky furniture. This article describes a method and control techniques for a humanoid robot to perform the manipulation of a large object through whole-body motion by applying this pivoting motion. For this purpose, first the object is manipulated by two arms of a humanoid robot using impedance control for grasping, together with body balancing control while the robot stays at the same place. Next, the movement of the humanoid robot itself is performed by stepping motion with the help of resolved momentum control to guarantee the robot stability. The proposed manipulation is validated through dynamic simulation and real hardware experiment of the humanoid robot HRP-2 performing the pivoting task.