MDPRP: A Q-learning approach for the joint control of beaconing rate and transmission power in VANETs

Vehicular ad-hoc communications rely on periodic broadcast beacons as the basis for most of their safety applications, allowing vehicles to be aware of their surroundings. However, an excessive beaconing load might compromise the proper operation of these crucial applications, especially regarding the exchange of emergency messages. Therefore, congestion control can play an important role. In this article, we propose joint beaconing rate and transmission power control based on policy evaluation. To this end, a Markov Decision Process (MDP) is modeled by making a set of reasonable simplifying assumptions which are resolved using Q-learning techniques. This MDP characterization, denoted as MDPRP (indicating Rate and Power), leverages the trade-off between beaconing rate and transmission power allocation. Moreover, MDPRP operates in a non-cooperative and distributed fashion, without requiring additional information from neighbors, which makes it suitable for use in infrastructureless (ad-hoc) networks. The results obtained reveal that MDPRP not only balances the channel load successfully but also provides positive outcomes in terms of packet delivery ratio. Finally, the robustness of the solution is shown since the algorithm works well even in those cases where none of the assumptions made to derive the MDP model apply.This work was supported in part by the AIM Project [Agencia Estatal de Investigación (AEI)/Fondo Europeo de Desarrollo Regional (FEDER), Unión Europea (UE)] under Grant TEC2016-76465-C2-1-R, in part by the Fundación Séneca, Región de Murcia, through the ATENTO Project, under Grant 20889/PI/18, and in part by the LIFE (Fondo SUPERA Covid-19 funded by the Agencia Estatal Consejo Superior de Investigaciones Científicas CSIC, Universidades Españolas, and Banco Santander). The work of Juan Aznar-Poveda was supported by the Spanish Ministerio de Educación, Cultura y Deporte (MECD) for the FPI Grant BES-2017-081061

Simultaneous data rate and transmission power adaptation in V2V communications: A deep reinforcement learning approach

In Vehicle-to-Vehicle (V2V) communications, channel load is key to ensuring the appropriate operation of safety applications as well as driver-assistance systems. As the number of vehicles increases, so do their communication messages. Therefore, channel congestion may arise, negatively impacting channel performance. Through suitable adjustment of the data rate, this problem would be mitigated. However, this usually involves using different modulation schemes, which can jeopardize the robustness of the solution due to unfavorable channel conditions. To date, little effort has been made to adjust the data rate, alone or together with other parameters, and its effects on the aforementioned sensitive safety applications remain to be investigated. In this paper, we employ an analytical model which balances the data rate and transmission power in a non-cooperative scheme. In particular, we train a Deep Neural Network (DNN) to precisely optimize both parameters for each vehicle without using additional information from neighbors, and without requiring any additional infrastructure to be deployed on the road. The results obtained reveal that our approach, called NNDP, not only alleviates congestion, leaving a certain fraction of the channel available for emergency-related messages, but also provides enough transmission power to fulfill the application layer requirements at a given coverage distance. Finally, NNDP is thoroughly tested and evaluated in three realistic scenarios and under different channel conditions, demonstrating its robustness and excellent performance in comparison with other solutions found in the scientific literature.This work was supported in part by the AEI/FEDER/UE [Agencia Estatal de Investigación (AEI), Fondo Europeo de Desarrollo Regional (FEDER), and Unión Europea (UE)] under Grant PID2020-116329GB-C22 [ARISE2: Future IoT Networks and Nano-networks (FINe)] and Grant PID2020-112675RB-C41 (ONOFRE-3), in part by the Fundación Séneca, Región de Murcia, under Grant 20889/PI/18 (ATENTO), and in part by the LIFE project (Fondo SUPERA COVID-19 through the Agencia Estatal Consejo Superior de Investigaciones Científicas CSIC, Universidades Españolas, and Banco Santander). The work of Juan Aznar-Poveda was supported by the Spanish Ministerio de Educación, Cultura y Deporte (MECD) through the Formación de Personal Investigador (FPI) Predoctoral Scholarship under Grant BES-2017-08106

Approximate reinforcement learning to control beaconing congestion in distributed networks

In vehicular communications, the increase of the channel load caused by excessive periodical messages (beacons) is an important aspect which must be controlled to ensure the appropriate operation of safety applications and driver-assistance systems. To date, the majority of congestion control solutions involve including additional information in the payload of the messages transmitted, which may jeopardize the appropriate operation of these control solutions when channel conditions are unfavorable, provoking packet losses. This study exploits the advantages of non-cooperative, distributed beaconing allocation, in which vehicles operate independently without requiring any costly road infrastructure. In particular, we formulate the beaconing rate control problem as a Markov Decision Process and solve it using approximate reinforcement learning to carry out optimal actions. Results obtained were compared with other traditional solutions, revealing that our approach, called SSFA, is able to keep a certain fraction of the channel capacity available, which guarantees the delivery of emergency-related notifications with faster convergence than other proposals. Moreover, good performance was obtained in terms of packet delivery and collision ratios.This research has been supported by the projects AIM, ref. TEC2016-76465-C2-1-R, ARISE2 “Future IoT Networks and Nano-networks (FINe)” ref. PID2020-116329GB-C22, ONOFRE-3, ref. PID2020-112675RB-C41 [Agencia Estatal de Investigación (AEI), European Regional Development Fund (FEDER), European Union (EU)], ATENTO, ref. 20889/PI/18 (Fundación Séneca, Región de Murcia), and LIFE [Fondo SUPERA Covid-19, funded by Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC), Universidades Españolas and Banco Santander]. J.A.P. thanks the Spanish MECD for an FPI grant ref. BES-2017-081061. Finally, the authors acknowledge Laura Wettersten for her contribution in reviewing the grammar and spell of the manuscript

Levels in the evolution of continuous improvement: A multiple case study

[ES] Objeto: El modelo de evolución de la mejora continua en las empresas está en un estado intermedio de desarrollo. En investigaciones previas se han planteado y validado las etapas o niveles y los comportamientos o conductas asociadas a cada una de ellas en los procesos de mejora continua. Sin embargo no está clara la relación entre etapas, rutinas entendidas como conjuntos de comportamientos y facilitadores. En este trabajo se propone una definición conceptual diferenciada para los facilitadores y para las conductas de la mejora continua. También se ha recopilado y resumido un listado de los facilitadores que dan soporte al desarrollo de la mejora continua en la empresa y propone un modelo de cuándo y cómo se activan los facilitadores y el impacto que tienen esos facilitadores para ir avanzando en las diferentes etapas de evolución del programa de mejora continua. Diseño/metodología/enfoque: Estudio cualitativo multicaso con 4 empresas medianas, líderes en sus sectores, y con recursos económicos. Aportaciones y resultados: Presenta una propuesta de relación entre facilitadores, etapas de evolución y sus conductas asociadas y pone de manifiesto que la evolución de la implantación de la mejora continua no se trata de un continuo incremental, sino que existe un punto de discontinuidad entre las etapas 3 y 4, que exige un cambio radical en el proceso de implantación. Originalidad / Valor añadido: Extiende el modelo de Bessant, Caffyn y Gallagher (2001) explicitando cómo avanzar en el desarrollo de la implementación de unos niveles a otros superiores a través de la activación de los facilitadores adecuados. También presenta ejemplos de aplicación que pueden resultar muy ilustrativos para los directivos de producción. Además, plantea una secuencia de activación de los facilitadores que permite orientar a los mandos en la toma de decisiones relacionadas con la implantación y despliegue de la mejora continua en sus empresas.[EN] Purpose: The evolution model of continuous improvement is at an intermediate stage of development. Previous research had been raised and validated levels and behaviors of continuous improvement. However, there is no clear relationship between levels, routines in terms of group of behaviours, and enablers. We propose a differentiated conceptual definition for facilitators and for the behaviors. We have also collected and summarized a list of enablers that support the development of continuous improvement. In addition, we propose a model of when and how to activate the enablers and the impact of these enablers to go forward at different stages of evolution of the continuous improvement. Design/methodology: Qualitative Multicase study with 4 midsize businesses with financial resources and leaders in their industries. Findings: Presents a relationship between facilitators, phases of evolution and its associated behaviors and demonstrates that the evolution of the implementation of continuous improvement is not a continuous incremental, but there is a point of discontinuity between stages 3 and 4, which requires a radical change in the implementation process. Originality/value: Extend the model of Bessant et al. (2001) explaining how to advance the implementation to higher levels of continuous improvement through the activation of appropriate facilitators. It also presents examples of applications that can be very illustrative for production managers. Also raises an activation sequence of facilitators for guiding the manager in making decisions related to the implementation and deployment of continuous improvement in their companies.El presente trabajo se ha desarrollado gracias a la ayuda DPI2010-18243 del Ministerio de Ciencia e Innovación del Gobierno de España dentro del programa de Proyectos de Investigación Fundamental no orientada, con el título "COORDINACION DE OPERACIONES EN REDES DE SUMINISTRO/DEMANDA AJUSTADAS, RESILIENTES A LA INCERTIDUMBRE: MODELOS Y ALGORITMOS PARA LA GESTION DE LA INCERTIDUMBRE Y LA COMPLEJIDAD" y del proyecto PAID-06-12-SP20120717 (UPV) PATH DEPENDENCE Y TOMA DE DECISIONES PARA SELECCIÓN DE HERRAMIENTAS Y PRÁCTICAS DE LEAN MANUFACTURING.Marín García, JA.; Bautista Poveda, Y.; García Sabater, JJ. (2014). Etapas en la evolución de la mejora continua: Estudio multicaso. Intangible Capital. 10(3):584-618. https://doi.org/10.3926/ic.425S58461810

Etapas en la evolución de la mejora continua:. ¿cómo viven las empresas el proceso? Estudio de un caso

Marín García, JA.; Bautista Poveda, Y.; García Sabater, JJ. (2012). Etapas en la evolución de la mejora continua:. ¿cómo viven las empresas el proceso? Estudio de un caso. Economía Industrial. (384):153-163. http://hdl.handle.net/10251/57542S15316338

Contribución al conocimiento de la pteridoflora de Andalucía: sobre el género Ophioglossum L. en Almería

Contribution to the knowledge about Andalusian pteridophyte flora: on the genus Ophiglossum L. inAlmeríaPalabras clave. Biodiversidad, Corología, Montañas Béticas, Sureste ibérico.Key words. Biodiversity, Chorology, Baetic Ranges, South-eastern Iberian Peninsula

Initial clinical and treatment patterns of advanced differentiated thyroid cancer: ERUDIT study

Advanced differentiated thyroid cancer; Epidemiological study; Survival prognostic factorsCáncer de tiroides diferenciado avanzado; Estudio epidemiológico; Factores pronósticos de supervivenciaCàncer de tiroide diferenciat avançat; Estudi epidemiològic; Factors pronòstics de supervivènciaBackground Up to 30% of differentiated thyroid cancer (DTC) will develop advanced-stage disease (aDTC) with reduced overall survival (OS). Objective The aim of this study is to characterize initial diagnosis of aDTC, its therapeutic management, and prognosis in Spain and Portugal. Methods A multicentre, longitudinal, retrospective study of adult patients diagnosed with aDTC in the Iberian Peninsula was conducted between January 2007 and December 2012. Analyses of baseline characteristics and results of initial treatments, relapse- or progression-free survival ((RP)FS) from first DTC diagnosis, OS, and prognostic factors impacting the evolution of advanced disease were evaluated. Results Two hundred and thirteen patients (median age: 63 years; 57% female) were eligible from 23 hospitals. Advanced disease presented at first diagnosis (de novo aDTC) included 54% of patients, while 46% had relapsed from early disease (recurrent/progressive eDTC). At initial stage, most patients received surgery (98%) and/or radioiodine (RAI) (89%), with no differences seen between median OS (95% CI) (10.4 (7.3–15.3) years) and median disease-specific-survival (95% CI) (11.1 (8.7–16.2) years; log-rank test P = 0.4737). Age at diagnosis being <55 years was associated with a lower risk of death (Wald chi-square (Wc-s) P < 0.0001), while a poor response to RAI to a higher risk of death ((Wc-s) P < 0.05). In the eDTC cohort, median (RP)FS (95% CI) was of 1.7 (1.0–2.0) years after RAI, with R0/R1 surgeries being the only common significant favourable factor for longer (RP)FS and time to aDTC ((Wc-s) P < 0.05). Conclusion Identification of early treatment-dependent prognostic factors for an unfavourable course of advanced disease is possible. An intensified therapeutic attitude may reverse this trend and should be considered in poor-performing patients. Prospective studies are required to confirm these findings.ERUDIT study was sponsored and funded by Eisai Farmacéutica S.A. (Madrid, Spain)

Dispositivo y método para la medición de ácido ascórbico y antocianos en zumos

Número de publicación: 2 728 448 Número de solicitud: 201930555Dispositivo y método para la medición de ácido ascórbico y antocianos en zumos. Un dispositivo y un método para la medición de ácidoascórbico y antocianos en zumos que comprende un sensor (1) amperométrico que comprende un primer electrodo de trabajo (3) y un segundo electrodo de trabajo (4); unos medios electrónicos de captura y procesado de datos (6, 7, 8, 9); una interfaz gráfica de gestión y/o configuración (10); y donde el primer electrodo de trabajo (3) no está tratado con ascorbatooxidasa y un segundo electrodo de trabajo (4) que está tratado con ascorbato oxidasa; y donde los medios electrónicos (6, 7, 8, 9) están configurados para estimular el sensor (1) según un rango de tensiones predefinido en función del tipo de zumo seleccionado por un usuario en la interfaz gráfica de gestión y/o configuración (10), y obtener simultáneamente la lectura de corriente debida a la oxidación del zumo estudiado.Universidad Politécnica de Cartagen

Plants on Rich-Magnesium Dolomite Barrens: A Global Phenomenon

For botanists and ecologists, the close link between some plants and substrates, such as serpentine or gypsum, is well known. However, the relationship between dolomite and its flora has been much less studied, due to various causes. Its diffuse separation from limestone and the use of a vague approach and terminology that, until now, no one has tried to harmonize are among these reasons. After carrying out an extensive review, completed with data on the distribution of plants linked to dolomite, the territories in which this type of flora appears at a global level were mapped using a geographic information system software. In addition, data on soils were collected, as well as on their influence on the ionomic profile of the flora. These data were completed with the authors’ own information from previous research, which also served to assess these communities’ degree of conservation and the genetic diversity of some of their characteristic species. The results showed that the so-called “dolomite phenomenon” is widely represented and is clearly manifested in the appearance of a peculiar flora, very rich in endemisms, on dry soils, poor in nutrients, and with a high Mg level. Although dolomite habitats cause adaptations in plants which are even more recognizable than those of other rock types, they have not been widely studied from an ecological, evolutionary, and conservation point of view because, so far, neither their characteristics nor their universal demarcation have been precisely defined

Spontaneous primary succession and vascular plant recovery in the Iberian gypsum quarries: insights for ecological restoration in an EU priority habitat

Gypsum covers a vast area of the Iberian Peninsula, making Spain a leader in its production. Gypsum is a fundamental raw material for modern societies. However, gypsum quarries have an obvious impact on the landscape and biodiversity. Gypsum outcrops host a high percentage of endemic plants and unique vegetation, considered a priority by the EU. Restoring gypsum areas after mining is a key strategy to prevent biodiversity loss. For the implementation of restoration approaches, understanding vegetation’s successional processes can be of invaluable help. To fully document the spontaneous succession in gypsum quarries and to evaluate its interest for restoration, 10 permanent plots of 20 × 50 m were proposed, with nested subplots, in which vegetation change was recorded for 13 years in Almeria (Spain). Through Species-Area Relationships (SARs), these plots’ floristic changes were monitored and compared to others in which an active restoration was carried out, as well as others with natural vegetation. Furthermore, the successional pattern found was compared to those recorded in 28 quarries distributed throughout the Spanish territory. The results show that an ecological pattern of spontaneous primary auto-succession is widely recurring in Iberian gypsum quarries, which is capable of regenerating the pre-existing natural vegetation