An Analytical Model for Estimating the Delay in Bluetooth Communications with Serial Port Profile

Bluetooth is currently a major technology for the deployment of wireless short range communications. This paper presents an ana-lytical model to compute the delay of Bluetooth transmissions with Serial Port Profile (SPP), which is nowadays widely utilized by commercial Bluetooth-enabled devices. In particular, the pro-posed equations permit to estimate the packet delay in ideal transmission conditions (when no retransmission occurs) and also when environmental noise induces losses and consequently there exist a certain probability that a packet has to be retransmitted. The model takes into consideration the overhead and segmenta-tion introduced by the protocols involved in the transmission as well as the extra delay introduced by the retransmissions. The model has been empirically validated through the measurements of Bluetooth connections in an actual test-bed.Ministerio de Educación y Ciencia TEC2006-12211-C02-0

Characterization of Bluetooth Packet Delay in Noisy Environments

This letter presents an analytical model to compute the delay of Bluetooth transmissions with Serial Port Profile (SPP) when interferences cause packet retransmissions. In particular, the model takes into consideration the overhead and segmentation introduced by the protocol stack as well as the extra delay provoked by the retransmissions. The model is empirically validated through the measurements of actual Bluetooth connections.Ministerio de Educación y Ciencia TEC2006-12211-C02-0

Analysis of Bluetooth Transmission Delay in Personal Area Networks

Bluetooth is by far the most employed technology to develop practical applications of Wireless Personal Area Networks (WPAN). This paper studies the performance of Bluetooth transmissions that make use of the Bluetooth PAN (Personal Area Network) profile. In particular, the study offers an analytical model that defines the optimal bound for the end-to-end data delay. The proposed ‘delay budget’ takes into account the overhead and segmentation provoked by the protocols involved in the transmission of user data. The model is empirically validated by comparing its results with those obtained through the measurements of actual Bluetooh connections.Ministerio de Educación y Ciencia TEC2006-12211-C02-0

Overhead and Segmentation Mismatch Effect on Bluetooth WPAN Performance

Currently, Bluetooth is the most widely used technology for Wireless Personal Area Networks (WPAN). Quality-of-Service (QoS) support is critical to ensure bandwidth maximization for mobile applications based on this WPAN technology. The overhead introduced by the different layers of Bluetooth protocol may have a serious impact on WPAN performance. However, most studies of Bluetooth performance neglect this overhead and assume that data are directly transmitted over L2CAP (Logical Link Control and Adaptation Protocol) or even HCI (Host Controller Interface) layers. In fact, this option is not feasible in most Bluetooth applications, as they integrate actual devices that implement a particular Bluetooth profile, usually SPP (Serial Port Profile). The use of profiles cannot be disregarded as they guarantee the interoperability between devices from different vendors. The aim of this paper is to characterise the performance of a Bluetooth WPAN (specifically the end-to-end delay and the throughput) when profiles are utilised. This study takes into account the overhead added by the protocols taking part in the transmission of user data. This paper also explores the effect of segmentation mismatch that may appear when the maximum size for data in each layer of the architecture is different. The analysis has been focused on SPP and PAN (Personal Area Networks) profiles. In the case of the PAN profile, the study concludes that the network performance decreases for user data sizes greater than 1,472 bytes, since the excessive overhead added by the network layer is increased by the IP (Internet Proto-col) fragmentation. In the case of SPP, an inappropriate choice of the maximum data unit at RFCOMM (Radio Frequency Communication for Serial Cable Emulation Protocol based on ETSI TS 07.10) and L2CAP layers can also heavily affect the transmission delay

An Analytical Study of the Delay in Bluetooth Networks Using the Personal Area Network Profile

Bluetooth is the most employed technology to develop Wireless Personal Area Networks. This letter studies the performance of Bluetooth transmissions that make use of the PAN (Personal Area Network) profile. In particular, the study offers an analytical model that defines the optimal bound for the end-to-end data delay. The proposed ’delay budget’ takes into account the overhead and segmentation provoked by the protocols involved in the transmission of user data. The model is empirically validated by comparing its results with those obtained through the measurements of actual Bluetooh connections.Ministerio de Educación y Ciencia TEC2006-12211-C02-0

Prototyping of a Remote Monitoring System for a medical Personal Area Network using Python

This paper presents a prototype developed in Python of a pervasive mobile health system aimed at monitoring a patient in indoor and outdoor environments continuously. The system is based on a Bluetooth PAN (Personal Area Network), worn by the patient, whose master node, a smartphone, collects information about patient's location and health status and detects emergency situations. These data are sent to a central server through Wi-Fi or GPRSIUMTS, which allows physicians to get access to patient data and configure the PAN sensors remotely using a conventional web browser.Ministerio de Educación y Ciencia TEC2006-12211- C02-01/TC

Seed dispersal by macaws shapes the landscape of an Amazonian ecosystem

Seed dispersal is one of the most studied plant–animal mutualisms. It has been proposed that the dispersal of many large-seeded plants from Neotropical forests was primarily conducted by extinct megafauna, and currently by livestock. Parrots can transport large fruits using their beaks, but have been overlooked as seed dispersers. We demonstrate that three macaws (Ara ararauna, A. glaucogularis and A. severus) are the main dispersers of the large-seeded motacú palm Attalea princeps, which is the biomass-dominant tree in the Bolivian Amazonian savannas. Macaws dispersed fruits at high rates (75– 100% of fruits) to distant (up to 1200 m) perching trees, where they consumed the pulp and discarded entire seeds, contributing to forest regeneration and connectivity between distant forests islands. The spatial distribution of immature palms was positively associated to the proximity to macaws’ perching trees and negatively to the proximity to cattle paths. The disperser role of livestock, presumably a substitute for extinct megafauna, had little effect due to soil compaction, trampling and herbivory. Our results underscore the importance of macaws as legitimate, primary dispersers of large-seeded plants at long distances and, specifically, their key role in shaping the landscape structure and functioning of this Amazonian biomePeer reviewe

A Smart Phone-based Personal Area Network for Remote Monitoring of Biosignals

This paper presents a system whose purpose is to monitor a patient continuously from indoor or outdoor environments. The system is based on a Bluetooth PAN, carried by the patient, whose central node, a smart phone, compiles information about patient’s location and health status. These data are encrypted to be sent to a server through Wifi or GPRS/UMTS. The system provides facilities to access to patient’s data, even from a smart phone by a J2ME application. It also allows to configure remotely the threshold values used to detect emergency situations.Ministerio de Eduación y Ciencia TEC2006-12211-C02-01/TCMMinisterio de Educación y Ciencia TIC2003- 07953-C02-0

Occupancy and abundance of large macaws in the Beni savannahs, Bolivia

Fil: Berkunsky, Igor. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Cepeda, Rosana E.. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Marinelli, Claudia. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Simoy, María Verónica. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Daniele, Gonzalo. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Kacoliris, Federico Pablo. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Díaz Luque, José A.. Blue-throated Macaw Conservation Project. World Parrot Trust. Trinidad; BoliviaFil: Gandoy, Facundo. Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable. Universidad Nacional del Centro de la Provincia de Buenos Aires. Tandil; ArgentinaFil: Aramburú, Rosana Mariel. División Zoología Vertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Gilardi, James D.. Blue-throated Macaw Conservation Project. World Parrot Trust. Trinidad; Bolivi

Évaluation de l'utilisation d'îles forestières par des espèces de perroquets dans une savane néotropicale

Understanding the effect of habitat fragmentation is a fundamental yet complicated aim of many ecological studies. Beni savanna is a naturally fragmented forest habitat, where forest islands exhibit variation in resources and threats. To understand how the availability of resources and threats affect the use of forest islands by parrots, we applied occupancy modeling to quantify use and detection probabilities for 12 parrot species on 60 forest islands. The presence of urucuri (Attalea phalerata) and macaw (Acrocomia aculeata) palms, the number of tree cavities on the islands, and the presence of selective logging,and fire were included as covariates associated with availability of resources and threats. The model-selection analysis indicated that both resources and threats variables explained the use of forest islands by parrots. For most species, the best models confirmed predictions. The number of cavities was positively associated with use of forest islands by 11 species. The area of the island and the presence of macaw palm showed a positive association with the probability of use by seven and five species, respectively, while selective logging and fire showed a negative association with five and six species, respectively. The Blue-throated Macaw (Ara glaucogularis), the critically endangered parrot species endemic to our study area, was the only species that showed a negative association with both threats. Monitoring continues to be essential to evaluate conservation and management actions of parrot populations. Understanding of how species are using this natural fragmented habitat will help determine which fragments should be preserved and which conservation actions are needed.La compréhension de l'effet de la fragmentation de l'habitat est l'objectif fondamental mais compliqué de nombreuses recherches en écologie. La savane de Beni est un milieu forestier naturellement fragmenté dans lequel les îles forestières diffèrent sur le plan des ressources et des menaces. Afin de comprendre à quel point la disponibilité des ressources et les menaces ont une influence sur l'utilisation d'îles forestières par les perroquets, nous avons appliqué des modèles de présence pour quantifier l'utilisation et la probabilité de détection de 12 espèces de perroquets sur 60 îles forestières. La présence de palmiers canne (Acrocomia aculeata) et de palmiers urucuri (Attalea phalerata), le nombre de cavités d'arbres sur les îles et la présence de coupes sélectives et de feu ont été inclus comme covariables associées à la disponibilité des ressources et aux menaces. L'analyse de la sélection de modèles a indiqué que les variables relatives aux ressources et celles relatives aux menaces expliquaient l'utilisation d'îles forestières par les perroquets. Pour la plupart des espèces de perroquets, les meilleurs modèles ont confirmé les prédictions. Le nombre de cavités était positivement associé avec l'utilisation d'îles forestières chez 11 espèces. La superficie de l'île et la présence de palmiers canne étaient positivement associées avec la probabilité d'utilisation chez 7 et 5 espèces, respectivement, tandis que la coupe sélective et le feu étaient négativement associés chez 5 et 6 espèces, respectivement. L'Ara canindé (Ara glaucogularis), espèce de perroquet en voie de disparition critique endémique à notre aire d'étude, a été la seule espèce qui a montré une association négative avec les deux menaces. Le suivi demeure essentiel pour l'évaluation des mesures de conservation et de gestion des populations de perroquets. La compréhension de l'utilisation de ce milieu naturellement fragmenté par les espèces contribuera à déterminer quelles parcelles devraient être protégées et quelles mesures de conservation sont nécessaires.Facultad de Ciencias Naturales y Muse