19 research outputs found

    Operational Squadron Scheduling

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    The 28th Operational Weather Squadron (28th OWS) is responsible for producing and disseminating mission planning and execution weather analyses and forecasts. The squadron must prepare schedules that meet the needs of their mission while dealing with real-world constraints such as time windows, task priorities, and intermittent recurring missions. The 28th OWS\u27s manning consists of active duty, deployed in-place, reserve, civilian and contract personnel. In this research, a scheduling model and algorithm are provided as an approach to crew scheduling for the 28th Operational Weather Squadron. Scheduling in the 28th OWS is complex and can be time consuming. This model will reduce the time and burden of scheduling the squadron

    Impacts of the Local arm on the local circular velocity inferred from the Gaia DR3 young stars in the Milky Way

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    A simple one-dimensional axisymmetric disc model is applied to the kinematics of OB stars near the Sun obtained from Gaia DR3 catalogue. The model determines the 'local centrifugal speed' Vc(R0)V_\mathrm{c}(R_{0}) - defined as the circular velocity in the Galactocentric rest frame, where the star would move in a near-circular orbit if the potential is axisymmetric with the local potential of the Galaxy. We find that the Vc(R0)V_\mathrm{c}(R_{0}) values and their gradient vary across the selected region of stars within the solar neighbourhood. By comparing with an N-body/hydrodynamic simulation of a Milky Way-like galaxy, we find that the kinematics of the young stars in the solar neighbourhood is affected by the Local arm, which makes it difficult to measure Vc(R0)V_\mathrm{c}(R_{0}). However, from the resemblance between the observational data and the simulation, we suggest that the known rotational velocity gap between the Coma Bernices and Hyades-Pleiades moving groups could be driven by the co-rotation resonance of the Local arm, which can be used to infer the azimuthally averaged circular velocity. We find that Vc(R)V_\mathrm{c}(R) obtained from the D<2\mathrm{D}<2 kpc sample is well matched with this gap at the position of the Local arm. Hence, we argue that our results from the D<2\mathrm{D}<2 kpc sample, Vc(R0)=233.95±2.24V_\mathrm{c}(R_{0})= 233.95\pm2.24 km s−1\mathrm{s}^{-1}, is close to the azimuthally averaged circular velocity rather than the local centrifugal speed, which is influenced by the presence of the Local arm.Comment: 13 pages, 11 figure

    Full orbital solution for the binary system in the northern Galactic disc microlensing event Gaia16aye

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    Gaia16aye was a binary microlensing event discovered in the direction towards the northern Galactic disc and was one of the first microlensing events detected and alerted to by the Gaia space mission. Its light curve exhibited five distinct brightening episodes, reaching up to I? =? 12 mag, and it was covered in great detail with almost 25 000 data points gathered by a network of telescopes. We present the photometric and spectroscopic follow-up covering 500 days of the event evolution. We employed a full Keplerian binary orbit microlensing model combined with the motion of Earth and Gaia around the Sun to reproduce the complex light curve. The photometric data allowed us to solve the microlensing event entirely and to derive the complete and unique set of orbital parameters of the binary lensing system. We also report on the detection of the first-ever microlensing space-parallax between the Earth and Gaia located at L2. The properties of the binary system were derived from microlensing parameters, and we found that the system is composed of two main-sequence stars with masses 0.57 ± 0.05 M? and 0.36 ± 0.03 M? at 780 pc, with an orbital period of 2.88 years and an eccentricity of 0.30. We also predict the astrometric microlensing signal for this binary lens as it will be seen by Gaia as well as the radial velocity curve for the binary system. Events such as Gaia16aye indicate the potential for the microlensing method of probing the mass function of dark objects, including black holes, in directions other than that of the Galactic bulge. This case also emphasises the importance of long-term time-domain coordinated observations that can be made with a network of heterogeneous telescopes

    Bright Mini-outburst Ends the 12 yr Long Activity of the Black Hole Candidate Swift J1753.5-0127

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    We present optical, UV, and X-ray monitoring of the short orbital period black hole X-ray binary candidate Swift J1753.5-0127, focusing on the final stages of its 12 yr long outburst that started in 2005. From 2016 September onward, the source started to fade, and within 3 months, the optical flux almost reached the quiescent level. Soon after that, using a new proposed rebrightening classification method, we recorded a mini-outburst and a reflare in the optical light curves, peaking in 2017 February (V similar to 17.0) and May (V similar to 17.9), respectively. Remarkably, the mini-outburst has a peak flux consistent with the extrapolation of the slow decay before the fading phase preceding it. The following reflare was fainter and shorter. We found from optical colors that the temperature of the outer disk was similar to 11,000 K when the source started to fade rapidly. According to the disk instability model, this is close to the critical temperature when a cooling wave is expected to form in the disk, shutting down the outburst. The optical color could be a useful tool to predict decay rates in some X-ray transients. We notice that all X-ray binaries that show mini-outbursts following a main outburst are short orbital period systems (<7 hr). In analogy with another class of short-period binaries showing similar mini-outbursts, the cataclysmic variables of the RZ LMi type, we suggest that mini-outbursts could occur if there is a hot inner disk at the end of the outburst decay

    DETERMINING THE LEVEL OF THREAT IRAN POSES TO OIL OUTPUT IN THE GULF REGION

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    With its abundant oil resources and as largest producer of oil in the world, the Arabian Gulf region is of crucial importance to the world. And, oil output from the region has been under threat from Iran since that country’s revolution in 1979. Using academic research as well as available reports from expert panels, government agencies, and media, this thesis examines the level of threat Iran poses to the Gulf oil industry in view of Iran's key military capabilities, including its naval and air capabilities, which could be used to disrupt Arabian Gulf oil production and shipping. This thesis focuses on case studies of specific incidents in which Iran has used these capabilities for similar ends in past attacks, including the 2019 sabotage attacks on civilian ships near Al Fujairah and the Gulf of Oman, and the combined cruise missile and drone attack on Saudi Arabia’s Shaybah and Aramco Abqaiq facilities. These case studies help establish how Iran can use its military capabilities against its neighbors and other adversaries in potential future attacks related to regional oil production and transport. Moreover, the analysis assesses the extent of the damage from such attacks, the constraints Iran faces in orchestrating its attacks, and the likelihood that it will attempt to take such action in the future.Commander, Royal Bahrain Naval ForceApproved for public release. distribution is unlimite

    Dynamics of three qubit systems in a noisy environment

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    Some properties of three-qubit systems interacting with a noisy environment are discussed. The amount of the survival entanglement is quantified for the GHZ and W states. It is shown that the entanglement decay depends on the noise type ( correlated or non-correlated), the number of interacting qubits with the environment and the initial state which passes through this noisy environment. In general, the GHZ state is more fragile than the W state. The phenomena of entanglement sudden death appears in GHZ state only for non-correlated noise.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
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