3,646 research outputs found
The Effects of Music Genre on Cycling Performance and Perceived Exertion
Many people claim that music enhances their exercise experience. To our knowledge, no studies have analyzed the effect of music genre on exercise performance and perceived effort.
Purpose: The purpose of this study was to analyze the effect of music genre on effort as well as perceived exertion while exercising.
Methods: Eighteen untrained individuals, age 18-22, participated in this study. Participants performed two 25-minute exercise trials on a Monark bicycle ergometer. Participants were randomized to a music genre (either hip-hop, country or classical) and to condition (music or no music). Rating of perceived exertion (RPE), heart rate (HR), and resistance were recorded for the first ten minutes, while the same three measures and total calories burned were recorded for the final fifteen.
Results: No significant difference was found in RPE between music and no music (p=0.477). The results of the Tukey post-hoc showed a significant increase in caloric expenditure between country music and hip-hop music (p=.008). There were no differences in RPE (F2,17=1.45, p=0.265) and music preference (F2,17=3.21, p=0.069) across genre.
Conclusion: Based on these results, exercise performance and perceived effort were similar with or without music. When examining the effects of music genre, listening to country music increased caloric expenditure when compared to hip-hop music
Collectivism And Religious Affiliation As Predictors Of The Multidimensional Measure Of Leader-Member Exchange (LMX-MDM)
Drawing upon the existing literature, this study investigated the relationship between collectivism and religious affiliation with the four Leader-Member Exchange (LMX) dimensions of Contribution, Loyalty, Affect, and Professional Respect. Â In this study of 300 adults, a significant positive relationship was found between the Multidimensional Measure of Leader-Member Exchange with collectivism and religious affiliation. Â With regard to the dimension of Contribution, collectivism and religious affiliation were both found to be strong predictors. Â With respect to Loyalty; collectivism and age helped to increase ratings of the supervisor and perceptions of leadership. Â Affect only had one significant predictor, collectivism. Â The LMX dimension of Professional Respect was found to have four significant predictors, including collectivism, religious affiliation, age, and years as a manager. Â Further regression analysis indicated that the diversity dimension, collectivism, was the driving factor of the relationship. This outcome indicated that collectivism was a strong predictor of how positively participants rated their attitudes toward their immediate supervisor and perceptions of leadership. Â The results of this study indicate that a relationship does exist between collectivism and religious affiliation with the Multidimensional Measure of Leader-Member Exchange, particularly with regard to the LMX dimensions of Contribution and Professional Respect. Furthermore, it strengthens the argument that organizations must be prepared to re-evaluate their policies with regard to diversity in the organization, particularly with respect to collectivism
Methodological proposal to identify the nationality of Twitter users through random forests
We disclose a methodology to determine the participants in discussions and their contribu tions in social networks with a local relationship (e.g., nationality), providing certain levels of trust and efficiency in the process. The dynamic is a challenge that has demanded studies and some approximations to recent solutions. The study addressed the problem of identify ing the nationality of users in the Twitter social network before an opinion request (of a politi cal nature and social participation). The employed methodology classifies, via machine learning, the Twitter usersâ nationality to carry out opinion studies in three Central American
countries. The Random Forests algorithm is used to generate classification models with small training samples, using exclusively numerical characteristics based on the number of times that different interactions among users occur. When averaging the proportions achieved by inferences of the ratio of nationals of each country, in the initial data, an average of 77.40% was calculated, compared to 91.60% averaged after applying the automatic clas sification model, an average increase of 14.20%. In conclusion, it can be seen that the sug gested set of method provides a reasonable approach and efficiency in the face of opinion problems
Stellar Populations and Star Cluster Formation in Interacting Galaxies with the Advanced Camera for Surveys
Pixel-by-pixel colour-magnitude and colour-colour diagrams - based on a
subset of the Hubble Space Telescope Advanced Camera for Surveys Early Release
Observations - provide a powerful technique to explore and deduce the star and
star cluster formation histories of the Mice and the Tadpole interacting
galaxies. In each interacting system we find some 40 bright young star clusters
(20 <= F606W (mag) <= 25, with a characteristic mass of ~3 x 10^6 Msun), which
are spatially coincident with blue regions of active star formation in their
tidal tails and spiral arms. We estimate that the main events triggering the
formation of these clusters occurred ~(1.5-2.0) x 10^8 yr ago. We show that
star cluster formation is a major mode of star formation in galaxy
interactions, with >= 35% of the active star formation in encounters occurring
in star clusters. This is the first time that young star clusters have been
detected along the tidal tails in interacting galaxies. The tidal tail of the
Tadpole system is dominated by blue star forming regions, which occupy some 60%
of the total area covered by the tail and contribute ~70% of the total flux in
the F475W filter (decreasing to ~40% in F814W). The remaining pixels in the
tail have colours consistent with those of the main disk. The tidally triggered
burst of star formation in the Mice is of similar strength in both interacting
galaxies, but it has affected only relatively small, spatially coherent areas.Comment: 23 pages in preprint form, 6 (encapsulated) postscript figures;
accepted for publication in New Astronomy; ALL figures (even the grey-scale
ones) need to be printed on a colour printer style files included; for
full-resolution paper, see http://www.ast.cam.ac.uk/STELLARPOPS/ACSpaper
Diversity As A Predictor Of Leadership Effectiveness
Drawing upon theexisting literature, this study investigated the significance of Diversity as apredictor of leadership effectiveness, as it relates to the MultidimensionalMeasure of Leader-Member Exchange (LMX-MDM).  A study of 300 working adults found that therewas a significant positive relationship between Diversity and the four LMXdimensions of Contribution, Loyalty, Affect, and Professional Respect.  Collectivism and religious affiliation wereboth strong predictors with regard to Contribution.  With regard to the dimension of Loyalty;collectivism, gender egalitarianism, and age helped to increase ratings of thesupervisor and perceptions of leadership.  Affect only had one significant predictor, collectivism. The LMX dimension of ProfessionalRespect was found to have four significant predictors, including collectivism, religiousaffiliation, age, and years as a manager.  Further regression analysis indicated that theDiversity dimension, Collectivism, was the driving factor of the relationship.  This outcome indicated that Collectivism was astrong predictor of how positively participants rated their attitudes towardtheir immediate supervisor and perceptions of leadership.  The results of this study indicate that diversity,particularly with regard to collectivism, is a positive predictor of leadershipeffectiveness using the LMX model.  Furthermore,it strengthens the argument that organizations must be prepared to re-evaluatetheir policies with regard to diversity in the organization, particularly withrespect to Collectivism
Liquid jet and droplet deformation induced by non-uniform acoustics radiation pressure distribution
International audienceThe present work focuses on non linear acoustic effects on an elliptic cylinder or an ellipsoid. These effects are encountered in acoustic levitation, ultrasonic standing wave atomization or two-phase flow combustion instabili-ties. Theoretical approaches mainly paid attention on the total radiation force, but a modeling of the distribution of acoustic radiation pressure around the object is needed to predict liquid object deformation. In the present study, a semi-analytical model is presented in order to compute the local radiation pressure as the only reason for liquid jet or droplet deformation. The method used here imposes an incident field to, a posteriori, compute the scattered field as a function of the object geometrical properties. A partial wave decomposition(PWD) model is developed to express incident and scattered fields by and immovable object with rigid boundary conditions. Radiation pressure is computed for progressive and standing wave fields. Validation of our method is done by comparing with the radiation force results from the literature. Results show that the larger the deformation, the higher the acoustic effects in a direction perpendicular to the acoustic wave axis. Introduction Non linear effects of acoustics are encountered in applications such as acoustic levitation, ultrasonic standing wave atomization or two-phase flow combustion instabilities occurring in rocket engines [1-4]. Most of the studies dealing with interaction of acoustics and spherical [5-9] or cylindrical [10-14] objects focused on the stationary radiation force. The main objective was there to determine the displacement of these objects. However, their deformation is also of a great interest in applications dealing with liquid objects. In studies on acoustically levitating droplets, some authors considered the radiation pressure distribution as the source of the stationnary deformation of the free surfaces [2, 15, 16]. They showed that spherical droplets became oblate when exposed to the radiation pressure. For cylindrical objects, it was experimentally proven that cylindrical liquid jets subjected to a low frequency standing wave were susceptible to be deformed into elliptic cylinders [17]. Thus, by relying on those results it appeared that knowing radiation pressure distribution around elliptic objects was necessary to correctly analyze the interaction between acoustics and deformed objects. Hasheminejad et al. [18, 19] developed an approach based on elliptic functions, namely Mathieu functions, to describe the acoustic scattered field. This is a powerful method, but limited in its applications due to the occurrence of Mathieu polynomials instability. Other authors considered a theoretical approach based on the expression of the incident and scattered waves by means of the formal cylindrical or spherical functions [17, 20-22]. All the studies cited above focused only on the modeling of the radiation force computed with the far field assumption avoiding the computation of radiation pressure distribution. To tackle the problem of object deformation induced by acoustics, it is needed to model the radiation pressure distribution. This is done here for elliptic cylinders and ellipsoids. The two-way coupling between incident acoustic harmonic plane waves and these objects is explored by computing the radiation pressure field and resulting radiation force. In the first section is presented the method used to compute the acoustic velocity potential field scattered by elliptic objects and the consequent computation of the radiation pressure and radiation force. Results showing the convergence of the method, its validation and the radiation pressure distribution are presented in the second section. Finally, the last section is dedicated to some conclusions
Proposal and validation of an industry 4.0 maturity model for SMEs
Purpose: This paper seeks to establish an Industry 4.0 maturity model for manufacturing SMEs. Thisresearch presents the characteristics of the proposed model, which takes the elements and the scope of thefourth industrial revolution, as well as the dimensions and assessment scales of some maturity modelsalready applied. Likewise, this document shows the modelling process and the modelâs validation in SMEsin the city of BogotĂĄ-Colombia.Design/methodology/approach: To determine the criteria of the maturity model, 6 major stages havebeen established: Literature Review, Development of the model; Validation of the model; Application ofthe model; Data analysis; and Conclusion and Recommendations. Findings: Considering the validation of some maturity models shown in the literature review, and alignedwith the purpose of this article, 8 dimensions have been established to measure the maturity level ofSMEs: Service; Operations; Quality; Products; Documented information- Big Data; Leadership andstrategy; Communication; and Culture and people. A model has been generated that allows evaluating thedegree of compliance in each dimension for manufacturing SMEs. The model can be applicable tocompanies in any industry. Also, it can determine the degree of implementation compliance of companiesin the same sector.Research limitations/implications: According to the literature reviewed, SMEs, especially those in LatinAmerica, still do not have a culture of applying the elements of Industry 4.0. Therefore, in the research, itwas not easy to understand the intrinsic variables of Industry 4.0 that SMEs have applied in different areas,which does not allow us to have the current context of SMEs and from that perspective to have a bettersimulation of the business model maturity.Practical implications: The model presented in this document serves as a basis for SMEs in LatinAmerica to establish a baseline measurement in relation to the application of Industry 4.0 elements incompanies.Social implications: What is intended with this work is to frame a baseline so that companies canunderstand their current maturity level in the terms that industry 4.0 could cover. Likewise, they cangenerate actions for the appropriation of new technologies that allow them to be more competitive. Thisdocument can be taken and applied by those entrepreneurs companies who wish to measure theiroperations.Originality/value: The essential point for the generation of the maturity level measurement model isfocused on determining the necessary dimensions on which the evaluation is based. In the literature found,most models focus their dimensions on measuring the digital in their processes and tangentially evaluate the organizational structure and the relationship between them. Additionally, the authors who address theorganization as a whole do not reveal the details for SMEs to self-evaluate. The models found have onlybeen implemented to evaluate one company along or individually. This model presents the coredimensions holistically and explicitly, taking important criteria such as quality, service, communication, andthe culture of all employees. Additionally, it shows in detail the model that allows to SMEs of themanufacturing sector to self-assess themselves in each dimension and in turn the degree of the businesssector in which they are or belongPeer Reviewe
Mantenimiento de lĂneas aĂ©reas desenergizadas con operaciĂłn normal a 13,2 kv
En el presente trabajo se desarrolla un estudio de las normas y procedimientos a seguir para llevar a cabo los respectivos tipos de mantenimiento de los sistemas elĂ©ctricos de distribuciĂłn, comprendiendo todas las etapas de los mismos. El objetivo del presente documento es aportar una visiĂłn de conjunto sobre el mantenimiento de redes de distribuciĂłn de energĂa elĂ©ctrica en el momento actual, en el que aparecen nuevos retos para las empresas distribuidoras de energĂa en un entorno cambiante, competitivo y cada vez mĂĄs complejo. Se describe un procedimiento sencillo y fĂĄcil de entender para la realizaciĂłn tanto de mantenimiento preventivo como de mantenimiento correctivo a las de redes elĂ©ctricas de 13,2 kV, asĂ como la herramienta necesaria y los requisitos y roles del personal involucrado en esta labor; teniendo siempre como prioridad la atenciĂłn al cliente, la seguridad, la calidad y la protecciĂłn del medio ambiente
Reliable, Context-Aware and Energy-Efficient Architecture for Wireless Body Area Networks in Sports Applications
RĂSUMĂ
Un RĂ©seau Corporel Sans Fil (RCSF, Wireless Body Area Network en anglais ou WBAN) permet de collecter de l'information Ă partir de capteurs corporels. Cette information est envoyĂ©e Ă un hub qui la transforme et qui peut aussi effectuer d'autres fonctions comme gĂ©rer des Ă©vĂ©nements corporels, fusionner les donnĂ©es Ă partir des capteurs, percevoir dâautres paramĂštres, exĂ©cuter les fonctions dâune interface dâutilisateur, et faire un lien vers des infrastructures de plus haut niveau et dâautres parties prenantes.
La rĂ©duction de la consommation d'Ă©nergie dâun RCSF est un des aspects les plus importants qui doit ĂȘtre amĂ©liorĂ© lors de sa conception. Cet aspect peut impliquer le dĂ©veloppement de protocoles de ContrĂŽles d'AccĂšs au Support (CAS, Media Access Control en anglais ou MAC), protocoles de transport et de routage plus efficients. Le contrĂŽle de la congestion est un autre des facteurs les plus importants dans la conception dâun RCSF, parce que la congestion influe directement sur la QualitĂ© De Service (QDS, Quality of Service en anglais ou QoS) et lâefficience en Ă©nergie du rĂ©seau. La congestion dans un RCSF peut produire une grande perte de paquets et une haute consommation dâĂ©nergie. La QDS est directement impactĂ©e par la perte de paquets. LâimplĂ©mentation de mesures additionnelles est nĂ©cessaire pour attĂ©nuer lâimpact sur la communication des RCSF.
Les protocoles de CAS pour RCSF devraient permettre aux capteurs corporels dâaccĂ©der rapidement au canal de communication et dâenvoyer les donnĂ©es au hub, surtout pour les Ă©vĂ©nements urgents tout en rĂ©duisant la consommation dâĂ©nergie. Les protocoles de transport pour RCSF doivent fournir de la fiabilitĂ© bout-Ă -bout et de la QDS pour tout le rĂ©seau. Cette tĂąche peut ĂȘtre accomplie par la rĂ©duction du ratio de perte de paquets (Packet Loss Ratio en anglais ou PLR) et de la latence tout en gardant l'Ă©quitĂ© et la faible consommation d'Ă©nergie entre les noeuds.
Le standard IEEE 802.15.6 suggĂšre un protocole de CAS qui est destinĂ© Ă ĂȘtre applicable Ă tous les types de RCSF; toutefois, ce protocole peut ĂȘtre amĂ©liorĂ© pour les RCSF utilisĂ©s dans le domaine du sport, oĂč la gestion du trafic pourrait ĂȘtre diffĂ©rente dâautres rĂ©seaux. Le standard IEEE 802.15.6 comprend la QDS, mais cela ne suggĂšre aucun protocole de transport ou systĂšme de contrĂŽle du dĂ©bit.
Le but principal de ce projet de recherche est de concevoir une architecture pour RCSF en trois phases : (i) Conception dâun mĂ©canisme sensible au contexte et efficient en Ă©nergie pour fournir une QDS aux RCSF; (ii) Conception dâun mĂ©canisme fiable et efficient en Ă©nergie pour fournir une rĂ©cupĂ©ration des paquets perdus et de lâĂ©quitĂ© dans les RCSF; et (iii) Conception dâun systĂšme de contrĂŽle du dĂ©bit sensible au contexte pour fournir un contrĂŽle de congestion aux RCSF. Finalement, ce projet de recherche propose une architecture fiable, sensible au contexte et efficiente en Ă©nergie pour RCSF utilisĂ©s dans le domaine du sport. Cette architecture fait face Ă quatre dĂ©fis : l'efficacitĂ© de l'Ă©nergie, la sensibilitĂ© au contexte, la qualitĂ© de service et la fiabilitĂ©.
La mise en place de cette solution aidera Ă lâamĂ©lioration des compĂ©tences, de la performance, de lâendurance et des protocoles dâentraĂźnement des athlĂštes, ainsi quâĂ la dĂ©tection des points faibles. Cette solution pourrait ĂȘtre prolongĂ©e Ă lâamĂ©lioration de la qualitĂ© de vie des enfants, des personnes malades ou ĂągĂ©es, ou encore aux domaines militaires, de la sĂ©curitĂ© et du divertissement.
LâĂ©valuation des protocoles et schĂ©mas proposĂ©s a Ă©tĂ© faite par simulations programmĂ©es avec le simulateur OMNeT++ et le systĂšme Castalia. PremiĂšrement, le protocole de CAS proposĂ© a Ă©tĂ© comparĂ© avec les protocoles de CAS suivants : IEEE 802.15.6, IEEE 802.15.4 et T-MAC (Timeout MAC). DeuxiĂšmement, le protocole de CAS proposĂ© a Ă©tĂ© comparĂ© avec le standard IEEE 802.15.6 avec et sans lâutilisation du protocole de transport proposĂ©. Finalement, le protocole de CAS proposĂ© et le standard IEEE 802.15.6 ont Ă©tĂ© comparĂ©s avec et sans lâutilisation du systĂšme de contrĂŽle du dĂ©bit proposĂ©.
Le protocole de CAS proposĂ© surpasse les protocoles de CAS IEEE 802.15.6, IEEE 802.15.4 et T-MAC dans le pourcentage de pertes de paquets dâurgence et normaux, lâefficacitĂ© en Ă©nergie, et la latence du trafic dâurgence et du trafic normal. Le protocole de CAS proposĂ© utilisĂ© avec le protocole du transport proposĂ© surpasse la performance du standard IEEE 802.15.6 dans le pourcentage de perte de paquets avec ou sans trafic dâurgence, lâefficacitĂ© en Ă©nergie, et la latence du trafic normal. Le systĂšme de contrĂŽle du dĂ©bit proposĂ© a amĂ©liorĂ© la performance du protocole de CAS proposĂ© et du standard IEEE 802.15.6 dans le pourcentage de perte de paquets avec ou sans trafic dâurgence, lâefficacitĂ© en Ă©nergie, et la latence du trafic dâurgence.----------ABSTRACT
Information collected from body sensors in a Wireless Body Area Network (WBAN) is sent to a hub or coordinator which processes the information and can also perform other functions such as managing body events, merging data from sensors, sensing other parameters, performing the functions of a user interface and bridging the WBAN to higher-level infrastructure and other stakeholders.
The reduction of the power consumption of a WBAN is one of the most important aspects to be improved when designing a WBAN. This challenge might imply the development of more efficient Medium Access Control (MAC), transport and routing protocols. Congestion control is another of the most important factors when a WBAN is designed, due to its direct impact in the Quality of Service (QoS) and the energy efficiency of the network. The presence of congestion in a WBAN can produce a big packet loss and high energy consumption. The QoS is also impacted directly by the packet loss. The implementation of additional measures is necessary to mitigate the impact on WBAN communications.
The MAC protocols for WBANs should allow body sensors to get quick access to the channel and send data to the hub, especially in emergency events while reducing the power consumption. The transport protocols for WBANs must provide end-to-end reliability and QoS for the whole network. This task can be accomplished through the reduction of both the Packet Loss Ratio (PLR) and the latency while keeping fairness and low power consumption between nodes.
The IEEE 802.15.6 standard suggests a MAC protocol which is intended to be applicable for all kinds of WBANs. Nonetheless, it could be improved for sports WBANs where the traffic-types handling could be different from other networks. The IEEE 802.15.6 standard supports QoS, but it does not suggest any transport protocol or rate control scheme.
The main objective of this research project is to design an architecture for WBANs in three phases: (i) Designing a context-aware and energy-efficient mechanism for providing QoS in WBANs; (ii) Designing a reliable and energy-efficient mechanism to provide packet loss recovery and fairness in WBANs; and (iii) Designing a context-aware rate control scheme to provide congestion control in WBANs. Finally, this research project proposes a reliable,
context-aware and energy-efficient architecture for WBANs used in sports applications, facing four challenges: energy efficiency, context awareness, quality of service and reliability.
The benefits of this solution will help to improve skills, performance, endurance and training protocols of athletes, and deficiency detection. Also, it could be extended to enhance the quality of life of children, ill and elderly people, and to security, military and entertainment fields.
The evaluation of the proposed protocols and schemes was made through simulations programed in the OMNeT++ simulator and the Castalia framework. First, the proposed MAC protocol was compared against the IEEE 802.15.6 MAC protocol, the IEEE 802.15.4 MAC protocol and the T-MAC (Timeout MAC) protocol. Second, the proposed MAC protocol was compared with the IEEE 802.15.6 standard with and without the use of the proposed transport protocol. Finally, both the proposed MAC protocol and the IEEE 802.15.6 standard were compared with and without the use of the proposed rate control scheme.
The proposed MAC protocol outperforms the IEEE 802.15.6 MAC protocol, the IEEE 802.15.4 MAC protocol and the T-MAC protocol in the percentage of emergency and normal packet loss, the energy effectiveness, and the latency of emergency and normal traffic. The proposed MAC protocol working along with the proposed transport protocol outperforms the IEEE 802.15.6 standard in the percentage of the packet loss with or without emergency traffic, the energy effectiveness, and the latency of normal traffic. The proposed rate control scheme improved the performance of both the proposed MAC protocol and the IEEE 802.15.6 standard in the percentage of the packet loss with or without emergency traffic, the energy effectiveness and the latency of emergency traffic
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