A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground-and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline, and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams.

This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands.

Abstract. The Burst Observer and Optical TransientExploring System (BOOTES) is considered as a part of the preparations for the ESA's satellite INTEGRAL, and is currently being developed in Spain, in collaboration with two Czech institutions. It makes use of two sets of wide-field cameras 240 kms apart, and two robotic 0.3-m telescopes. The first observing station (BOOTES-1) is located in Huelva (Spain) and the first light was obtained in July 1998. During the test phase, it has provided rapid follow-up observations for 5 GRBs detected by the BATSE aboard the CGRO. The system will fully operate in late 1999.

Abstract. We present multiwavelength (optical/near infrared/millimetre) observations of a short duration gamma-ray burst detected by Swift (GRB 050509b) collected between 0 seconds and ∼18.8 days after the event. No optical, near infrared or millimetre emission has been detected in spite of the well localised X-ray afterglow, confirming the elusiveness of the short duration events. We also discuss the possibility of the burst being located in a cluster of galaxies at z = 0.225 or beyond. In the former case, the spectral energy distribution of the neighbouring, potential host galaxy, favours a system harbouring an evolved dominant stellar population (age ∼360 Myr), unlike most long duration GRB host galaxies observed so far, i.e. thus giving support to a compact binary merger origin. Any underlying supernova that could be associated with this particular event should have been at least 3 magnitudes fainter than the type Ib/c SN 1998bw and 2.3 mag fainter than a typical type Ia SN.

No abstract

Smart cities are ecosystems where novel ideas and emerging technologies meet to improve economy, environment, governance, living, and mobility. One of the pillars of smart cities is transport, with the improvement of mobility and the reduction of traffic accidents being some of the current key challenges. With this purpose, this manuscript reviews the state-of-the-art of communications and applications in which different actors of the road are involved. Thus, the objectives of this survey are intended to determine who, when, and about what is being researched around smart cities. Particularly, the goal is to situate the focus of scientific and industrial progress on V2X, I2X, and P2X communication to establish a taxonomy that reduces ambiguous acronyms around the communication between vehicles, infrastructure, and pedestrians, as well as to determine what the trends and future technologies are that will lead to more powerful applications. To this end, this literature review article presents a comprehensive study including a representative collection of the 100 most cited papers and patents published in the literature together with a statistical bibliometric analysis of 14,364 keywords over 3422 contributions between 1997 and 2018. As a result, this work provides a technological profile considering different dimensions along the paper, such as the type of communication, use case, country, organization, terminology, and year.

ABSTRACT:This work develops a new educational simulation tool whose objective is to make attractive and practical teaching and learning in kinematics of serial robotic arms. At engineering laboratories in which practices with robotic arms are necessary for understanding fundamental concepts of theory, students need to accomplish a complete study attending to different aspects related with kinematics. Its graphic user interface (GUI) is a straightforward and easy-to-follow Denavit-Hartenberg (DH)-based method which helps at engineering practices without requiring a programming knowledge. We develop, in a theoretical way, both forward (FK) and inverse kinematics (IK), which are necessary to demonstrate the study of an educational robotic arm as a practical case. The interactive simulation tool allows defining DH parameters and geometry in serial arms with up to 5 degrees of freedom (DOF). Thus, the interest of this work lies in an innovative graphic environment which teaching professionals can use to study DH convention, observe the movement of serial robotic manipulators and map both forward and joint workspaces in a visual manner. This process is much simpler that interpreting the results in an analytic way. Furthermore, the generic capabilities of this simulation tool allow comparing different robot arm configurations (considering its physical parameters and mechanical characteristics previously known), both if robotic arms are physically available or not in lab.

A new educational simulation tool designed for the generic study of wireless networks, the Wireless Fidelity Simulator (WiFiSim), is presented in this paper. The goal of this work was to create and implement a didactic tool to improve the teaching and learning of computer networks by means of two complementary strategies: simulating the behavior and performance of communication protocols based on the IEEE 802.11 standard widely studied in networking courses, and providing with improved scope and realism for students engaged in wireless network design and modeling. The educational interest of this tool lies in the realism of the simulation, which provides a high level of interactivity and visual information through a highly configurable graphic user interface, as well as highly intuitive and easy-to-interpret graphic results. This educational tool was tested by computer networking teachers, students, and professionals. The experience demonstrated the effectiveness of the software and resulted in a significant improvement in the students' practical work, leading to enhanced learning and consolidation of theoretical concepts.