scholarly journals Probabilistic fibre-to-target assignment algorithm for multi-object spectroscopic surveys

2020 ◽  
Vol 635 ◽  
pp. A101 ◽  
Author(s):  
E. Tempel ◽  
P. Norberg ◽  
T. Tuvikene ◽  
T. Bensby ◽  
C. Chiappini ◽  
...  
Keyword(s):  
Exposure Time ◽  
Target Selection ◽  
Probabilistic Approach ◽  
Density Variation ◽  
Selection Function ◽  
Assignment Algorithm ◽  
Target Assignment ◽  
Single Field ◽  
Under Construction ◽  
Input Catalogue

Context. Several new multi-object spectrographs are currently planned or under construction that are capable of observing thousands of Galactic and extragalactic objects simultaneously. Aims. In this paper we present a probabilistic fibre-to-target assignment algorithm that takes spectrograph targeting constraints into account and is capable of dealing with multiple concurrent surveys. We present this algorithm using the 4-m Multi-Object Spectroscopic Telescope (4MOST) as an example. Methods. The key idea of the proposed algorithm is to assign probabilities to fibre-target pairs. The assignment of probabilities takes the fibre positioner’s capabilities and constraints into account. Additionally, these probabilities include requirements from surveys and take the required exposure time, number density variation, and angular clustering of targets across each survey into account. The main advantage of a probabilistic approach is that it allows for accurate and easy computation of the target selection function for the different surveys, which involves determining the probability of observing a target, given an input catalogue. Results. The probabilistic fibre-to-target assignment allows us to achieve maximally uniform completeness within a single field of view. The proposed algorithm maximises the fraction of successfully observed targets whilst minimising the selection bias as a function of exposure time. In the case of several concurrent surveys, the algorithm maximally satisfies the scientific requirements of each survey and no specific survey is penalised or prioritised. Conclusions. The algorithm presented is a proposed solution for the 4MOST project that allows for an unbiased targeting of many simultaneous surveys. With some modifications, the algorithm may also be applied to other multi-object spectroscopic surveys.

scholarly journals Effects of the selection function on metallicity trends in spectroscopic surveys of the Milky Way

2017 ◽  
Vol 606 ◽  
pp. A97 ◽  
Author(s):  
G. Nandakumar ◽  
M. Schultheis ◽  
M. Hayden ◽  
A. Rojas-Arriagada ◽  
G. Kordopatis ◽  
...  
Keyword(s):  
Stellar Population ◽  
Milky Way ◽  
Target Selection ◽  
Selection Function ◽  
Population Synthesis ◽  
Sample Distribution ◽  
Stellar Population Synthesis ◽  
Source Sample ◽  
Correction Terms ◽  
Metallicity Distribution

Context. Large spectroscopic Galactic surveys imply a selection function in the way they performed their target selection. Aims. We investigate here the effect of the selection function on the metallicity distribution function (MDF) and on the vertical metallicity gradient by studying similar lines of sight using four different spectroscopic surveys (APOGEE, LAMOST, RAVE, and Gaia-ESO), which have different targeting strategies and therefore different selection functions. Methods. We use common fields between the spectroscopic surveys of APOGEE, LAMOST, RAVE (ALR) and APOGEE, RAVE, Gaia-ESO (AGR) and use two stellar population synthesis models, GALAXIA and TRILEGAL, to create mock fields for each survey. We apply the selection function in the form of colour and magnitude cuts of the respective survey to the mock fields to replicate the observed source sample. We make a basic comparison between the models to check which best reproduces the observed sample distribution. We carry out a quantitative comparison between the synthetic MDF from the mock catalogues using both models to understand the effect of the selection function on the MDF and on the vertical metallicity gradient. Results. Using both models, we find a negligible effect of the selection function on the MDF for APOGEE, LAMOST, and RAVE. We find a negligible selection function effect on the vertical metallicity gradients as well, though GALAXIA and TRILEGAL have steeper and shallower slopes, respectively, than the observed gradient. After applying correction terms on the metallicities of RAVE and LAMOST with respect to our reference APOGEE sample, our observed vertical metallicity gradients between the four surveys are consistent within 1σ. We also find consistent gradient for the combined sample of all surveys in ALR and AGR. We estimated a mean vertical metallicity gradient of − 0.241 ± 0.028 dex kpc-1. There is a significant scatter in the estimated gradients in the literature, but our estimates are within their ranges. Conclusions. We have shown that there is a negligible selection function effect on the MDF and the vertical metallicity gradients for APOGEE, RAVE, and LAMOST using two stellar population synthesis models. Therefore, it is indeed possible to combine common fields of different surveys in studies using MDF and metallicity gradients provided their metallicities are brought to the same scale.

Q-learning based air combat target assignment algorithm

2016 ◽  
Author(s):  
Peng-cheng Luo ◽  
Jun-jie Xie ◽  
Wan-fang Che
Keyword(s):  
Q Learning ◽  
Assignment Algorithm ◽  
Target Assignment ◽  
Air Combat

scholarly journals Multi-Field versus Single-Field in the Supergravity Models of Inflation and Primordial Black Holes

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 115
Author(s):  
Sergei V. Ketov
Keyword(s):  
Power Spectra ◽  
Primordial Black Hole ◽  
Primordial Black Holes ◽  
Second Stage ◽  
Slow Roll ◽  
Field Versus ◽  
Cosmological Observations ◽  
Minimal Supergravity ◽  
Single Field ◽  
Under Construction

We review the models unifying inflation and Primordial Black Hole (PBH) formation, which are based on the modified (Starobinsky-type) supergravity. We begin with the basic (Starobinsky) inflationary model of modified gravity and its alpha-attractor-type generalizations for PBH production, and recall how all those single-field models can be embedded into the minimal supergravity. Then, we focus on the effective two-field models arising from the modified (Starobinsky-type) supergravity and compare them to the single-field models under review. Those two-field models describe double inflation whose first stage is driven by Starobinsky’s scalaron and whose second stage is driven by another scalar belonging to the supergravity multiplet. The power spectra are numerically computed, and it is found that the ultra-slow-roll regime gives rise to the enhancement (peak) in the scalar power spectrum leading to an efficient PBH formation. The resulting PBH masses and their density fraction (as part of dark matter) are found to be in agreement with cosmological observations. The PBH-induced gravitational waves, if any, are shown to be detectable by the ground-based and space-based gravitational interferometers under construction.

scholarly journals The Stars Kepler Missed: Investigating the Kepler Target Selection Function Using Gaia DR2

2021 ◽  
Vol 161 (5) ◽  
pp. 231
Author(s):  
Linnea M. Wolniewicz ◽  
Travis A. Berger ◽  
Daniel Huber
Keyword(s):  
Target Selection ◽  
Selection Function ◽  
Gaia Dr2

Robot Visual Design with the Panorama Synthesis Function with Manufacturing Technology

2013 ◽  
Vol 312 ◽  
pp. 705-709
Author(s):  
Wen Ming Wang ◽  
Ya Peng Yu
Keyword(s):  
Target Tracking ◽  
Real Time ◽  
Target Selection ◽  
Video Stream ◽  
Selection Function ◽  
Present System ◽  
Video File ◽  
Detection And Tracking ◽  
Time Image ◽  
Visual Range

Panorama synthesis is basis of the target tracking. Through the synthesis of panorama, can enlarge the visual range to capture for the cameras, in the big background, the suspicious target which needs to be tracked are more easily detected, then selects the target, and Tracks it. In the existing target tracking of robot integrated machine, adds panorama synthesis function and the suspicious target selection function, the target tracking runs only on selected target, make the tracking more targeted. In the Panorama synthesis module of the present system, there are two ways to obtain video stream that is real-time image stream from Cameras and the local AVI video file. Through the algorithm to judge the position relationship between two adjacent frames, finishes the image stitching, and displays panorama of the in the user interface in real time. By a particular target selection from users, complete moving object detection and tracking in motion camera environment. After the test, the system can meet the general needs of application oriented robot visual.

Cooperative dynamic weapon-target assignment algorithm of multiple missiles based on networks

2009 ◽  
Author(s):  
Chen Peng ◽  
Xing Liu ◽  
Xiaomin Mu ◽  
Yang Du ◽  
Sentang Wu
Keyword(s):  
Assignment Algorithm ◽  
Multiple Missiles ◽  
Target Assignment

Weapon–Target Assignment Algorithm for Simultaneous and Sequenced Arrival

2018 ◽  
Vol 41 (11) ◽  
pp. 2361-2373 ◽  
Author(s):  
Kyle Volle ◽  
Jonathan Rogers
Keyword(s):  
Assignment Algorithm ◽  
Target Assignment

Sensor-target assignment algorithm based on complementary principle

2018 ◽  
Author(s):  
WANG Jundi ◽  
XU Yunshan ◽  
XIAO Bingsong ◽  
XIA Haibao
Keyword(s):  
Assignment Algorithm ◽  
Target Assignment

Optimal Weapon-Target Assignment Algorithm for Closed-In Weapon Systems Considering Variable Burst Time

2021 ◽  
Vol 49 (5) ◽  
pp. 365-372
Author(s):  
Bosoek Kim ◽  
Chang-Hun Lee ◽  
Min-Jea Tahk ◽  
Da-Sol Kim ◽  
Sang-Hyun Kim ◽  
...  
Keyword(s):  
Weapon Systems ◽  
Assignment Algorithm ◽  
Target Assignment ◽  
Burst Time
Sign in / Sign up

Export Citation Format

Share Document