Showing papers by "Vaughn College of Aeronautics and Technology published in 2012"
Ohio State University1, Tel Aviv University2, Weizmann Institute of Science3, Massey University4, University of Warsaw5, Chungbuk National University6, Osaka University7, Nagoya University8, University of Notre Dame9, University of Auckland10, Victoria University of Wellington11, University of Manchester12, Vaughn College of Aeronautics and Technology13, University of Concepción14, University of Cambridge15, National Institute for Space Research16, Texas A&M University17, Princeton University18, University of Valencia19, Auckland University of Technology20, Korea Astronomy and Space Science Institute21
TL;DR: In the Mathematical and Physical Sciences: 1st Place (The Ohio State University Edward F. Hayes Graduate Research Forum) as mentioned in this paper, the authors of the paper as mentioned in this paper presented a mathematical and physical sciences model.
Abstract: Mathematical and Physical Sciences: 1st Place (The Ohio State University Edward F. Hayes Graduate Research Forum)
196 citations
TL;DR: In this article, the authors presented the analysis of four candidate short-duration binary microlensing events from the 2006-2007 MOA Project short-event analysis, which were discovered as a byproduct of an analysis designed to find short-timescale single-lens events that may be due to free-floating planets.
Abstract: We present the analysis of four candidate short-duration binary microlensing events from the 2006-2007 MOA Project short-event analysis. These events were discovered as a by-product of an analysis designed to find short-timescale single-lens events that may be due to free-floating planets. Three of these events are determined to be microlensing events, while the fourth is most likely caused by stellar variability. For each of the three microlensing events, the signal is almost entirely due to a brief caustic feature with little or no lensing attributable mainly to the lens primary. One of these events, MOA-bin-1, is due to a planet, and it is the first example of a planetary event in which the stellar host is only detected through binary microlensing effects. The mass ratio and separation are q (4.9 {+-} 1.4) Multiplication-Sign 10{sup -3} and s = 2.10 {+-} 0.05, respectively. A Bayesian analysis based on a standard Galactic model indicates that the planet, MOA-bin-1Lb, has a mass of m{sub p} = 3.7 {+-} 2.1 M{sub Jup} and orbits a star of M{sub *} = 0.75{sub -0.41}{sup +}0{sup .33} M{sub Sun} at a semimajor axis of a = 8.3{sub -2.7}{sup +4.5} AU. This is one of the most massivemore » and widest separation planets found by microlensing. The scarcity of such wide-separation planets also has implications for interpretation of the isolated planetary mass objects found by this analysis. If we assume that we have been able to detect wide-separation planets with an efficiency at least as high as that for isolated planets, then we can set limits on the distribution of planets in wide orbits. In particular, if the entire isolated planet sample found by Sumi et al. consists of planets bound in wide orbits around stars, we find that it is likely that the median orbital semimajor axis is >30 AU.« less
87 citations
TL;DR: In this article, the authors reported the discovery of a giant planet detected from the analysis of the light curve of a high-magnification microlensing event MOA 2010-BLG-477.
Abstract: Microlensing detections of cool planets are important for the construction of an unbiased sample to estimate the frequency of planets beyond the snow line, which is where giant planets are thought to form according to the core accretion theory of planet formation. In this paper, we report the discovery of a giant planet detected from the analysis of the light curve of a high-magnification microlensing event MOA 2010-BLG-477. The measured planet-star mass ratio is q = (2.181 {+-} 0.004) Multiplication-Sign 10{sup -3} and the projected separation is s = 1.1228 {+-} 0.0006 in units of the Einstein radius. The angular Einstein radius is unusually large {theta}{sub E} = 1.38 {+-} 0.11 mas. Combining this measurement with constraints on the 'microlens parallax' and the lens flux, we can only limit the host mass to the range 0.13 < M/M{sub Sun} < 1.0. In this particular case, the strong degeneracy between microlensing parallax and planet orbital motion prevents us from measuring more accurate host and planet masses. However, we find that adding Bayesian priors from two effects (Galactic model and Keplerian orbit) each independently favors the upper end of this mass range, yielding star and planet masses of M{sub *} = 0.67{supmore » +0.33}{sub -0.13} M{sub Sun} and m{sub p} = 1.5{sup +0.8}{sub -0.3} M{sub JUP} at a distance of D = 2.3 {+-} 0.6 kpc, and with a semi-major axis of a = 2{sup +3}{sub -1} AU. Finally, we show that the lens mass can be determined from future high-resolution near-IR adaptive optics observations independently from two effects, photometric and astrometric.« less
54 citations
Journal Article•
TL;DR: In this article, the advantages and disadvantages of grey relational analysis and TOPSIS for multiattribute decision-making are pointed out, and an effectiveness evaluation model of weapon systems by combining grey relational analyses and TOPsIS is proposed.
49 citations
Chungbuk National University1, University of Warsaw2, Osaka University3, Ohio State University4, University of Salerno5, University of St Andrews6, University of Toulouse7, University of Concepción8, University of Cambridge9, Nagoya University10, University of Notre Dame11, Massey University12, University of Auckland13, Victoria University of Wellington14, Vaughn College of Aeronautics and Technology15, European Southern Observatory16, Max Planck Society17, Liverpool John Moores University18, Las Cumbres Observatory Global Telescope Network19, Qatar Foundation20, Ames Research Center21, University of Göttingen22, Chinese Academy of Sciences23, Aarhus University24, University of Copenhagen25, Institut d'Astrophysique de Paris26, Korea Astronomy and Space Science Institute27, Technical University of Denmark28, University of Manchester29, Sharif University of Technology30, Keele University31, Heidelberg University32, National Institute for Space Research33, Texas A&M University34, Princeton University35, Auckland University of Technology36, University of Canterbury37, University of Tasmania38, University of Rijeka39, University of Vienna40, Space Telescope Science Institute41
TL;DR: In this article, the authors reported the detections and measurements of two binary stars from observations of microlensing events MOA-2011-BLG-090 and OGLE-2011 BLG-0417 and determined the binary masses by simultaneously measuring the Einstein radius and the lens parallax.
Abstract: Despite the astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view of stellar multiplicity across a broad range of physical parameters. In this paper, we report the detections and measurements of two binaries discovered from observations of microlensing events MOA-2011-BLG-090 and OGLE-2011-BLG-0417. Determinations of the binary masses are possible by simultaneously measuring the Einstein radius and the lens parallax. The measured masses of the binary components are 0.43M(circle dot) and 0.39M(circle dot) for MOA-2011-BLG-090 and 0.57M(circle dot) and 0.17M(circle dot) for OGLE-2011-BLG-0417 and thus both lens components of MOA-2011-BLG-090 and one component of OGLE-2011-BLG-0417 are M dwarfs, demonstrating the usefulness of microlensing in detecting binaries composed of low-mass components. From modeling of the light curves considering full Keplerian motion of the lens, we also measure the orbital parameters of the binaries. The blended light of OGLE-2011-BLG-0417 comes very likely from the lens itself, making it possible to check the microlensing orbital solution by follow-up radial-velocity observation. For both events, the caustic-crossing parts of the light curves, which are critical for determining the physical lens parameters, were resolved by high-cadence survey observations and thus it is expected that the number of microlensing binaries with measured physical parameters will increase in the future.
42 citations
Chungbuk National University1, University of Warsaw2, Osaka University3, Ohio State University4, University of Salerno5, University of St Andrews6, University of Toulouse7, University of Concepción8, University of Cambridge9, Nagoya University10, University of Notre Dame11, Massey University12, University of Auckland13, Victoria University of Wellington14, Vaughn College of Aeronautics and Technology15, European Southern Observatory16, Max Planck Society17, Liverpool John Moores University18, Las Cumbres Observatory Global Telescope Network19, Qatar Foundation20, Ames Research Center21, University of Göttingen22, Chinese Academy of Sciences23, Aarhus University24, University of Copenhagen25, Korea Astronomy and Space Science Institute26, Technical University of Denmark27, University of Manchester28, Sharif University of Technology29, Keele University30, Heidelberg University31, National Institute for Space Research32, Texas A&M University33, Princeton University34, Auckland University of Technology35, University of Canterbury36, Institut d'Astrophysique de Paris37, University of Tasmania38, University of Rijeka39, Vienna University of Technology40, Space Telescope Science Institute41
TL;DR: In this article, a case of central perturbations for which it is difficult to distinguish the planetary and binary interpretations is presented, where the peak of a lensing light curve affected by this perturbation appears to be blunt and flat.
Abstract: High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet or a binary companion. It is known that central perturbations induced by both types of companions can be generally distinguished due to the essentially different magnification pattern around caustics. In this paper, we present a case of central perturbations for which it is difficult to distinguish the planetary and binary interpretations. The peak of a lensing light curve affected by this perturbation appears to be blunt and flat. For a planetary case, this perturbation occurs when the source trajectory passes the negative perturbation region behind the back end of an arrowhead-shaped central caustic. For a binary case, a similar perturbation occurs for a source trajectory passing through the negative perturbation region between two cusps of an astroid-shaped caustic. We demonstrate the degeneracy for two high-magnification events of OGLE-2011-BLG-0526 and OGLE-2011-BLG-0950/MOA-2011-BLG-336. For OGLE-2011-BLG-0526, the χ2 difference between the planetary and binary model is ~3, implying that the degeneracy is very severe. For OGLE-2011-BLG-0950/MOA-2011-BLG-336, the stellar binary model is formally excluded with Δχ2 ~ 105 and the planetary model is preferred. However, it is difficult to claim a planet discovery because systematic residuals of data from the planetary model are larger than the difference between the planetary and binary models. Considering that two events observed during a single season suffer from such a degeneracy, it is expected that central perturbations experiencing this type of degeneracy is common.
34 citations
University of Salerno1, University of St Andrews2, University of Auckland3, University of Copenhagen4, Geological Museum5, Las Cumbres Observatory Global Telescope Network6, Queen Mary University of London7, University of Warsaw8, Massey University9, Heidelberg University10, Institut d'Astrophysique de Paris11, University of Toulouse12, University of Göttingen13, Chungbuk National University14, Ohio State University15, University of Exeter16, University of Manchester17, University of Cambridge18, Nagoya University19, Armagh Observatory20, Korea Astronomy and Space Science Institute21, Max Planck Society22, Pontifical Catholic University of Chile23, Ames Research Center24, University of Stuttgart25, Technical University of Denmark26, Sharif University of Technology27, Perimeter Institute for Theoretical Physics28, European Southern Observatory29, Keele University30, Liverpool John Moores University31, Spanish National Research Council32, Niels Bohr Institute33, University of Canterbury34, University of Notre Dame35, University of Tasmania36, Lawrence Livermore National Laboratory37, University of Rijeka38, Vienna University of Technology39, NASA Exoplanet Science Institute40, Space Telescope Science Institute41, University of Concepción42, Texas A&M University43, Princeton University44, Victoria University of Wellington45, Konan University46, Vaughn College of Aeronautics and Technology47, Osaka University48, National Taiwan Normal University49
TL;DR: In this article, a microlensing event OGLE-2008-BLG-510 is characterized by an evident asymmetric shape of the peak, promptly detected by the Automated Robotic Terrestrial Exoplanet Microlensing Search (ARTEMiS) system in real time.
Abstract: The microlensing event OGLE-2008-BLG-510 is characterized by an evident asymmetric shape of the peak, promptly detected by the Automated Robotic Terrestrial Exoplanet Microlensing Search (ARTEMiS) system in real time. The skewness of the light curve appears to be compatible both with binary-lens and binary-source models, including the possibility that the lens system consists of an M dwarf orbited by a brown dwarf. The detection of this
microlensing anomaly and our analysis demonstrate that: (1) automated real-time detection of weak microlensing anomalies with immediate feedback is feasible, efficient and sensitive, (2)
rather common weak features intrinsically come with ambiguities that are not easily resolved from photometric light curves, (3) a modelling approach that finds all features of parameter
space rather than just the ‘favourite model’ is required and (4) the data quality is most crucial, where systematics can be confused with real features, in particular small higher order
effects such as orbital motion signatures. It moreover becomes apparent that events with weak signatures are a silver mine for statistical studies, although not easy to exploit. Clues about
the apparent paucity of both brown-dwarf companions and binary-source microlensing events might hide here.
29 citations
TL;DR: In this article, a novel adaptive weighted differential game guidance law based on the game theory of mixed strategy is proposed, combining two guidance laws which are derived from the perfect and imperfect information pattern, respectively.
8 citations
Journal Article•
TL;DR: In this article, a model combining numerical simulation with trajectory simulation was established for the process of store separated from the plane by the second explore technologies of the CFD software(FLUENT) and the RNG k-e turbulence model.
Abstract: The model combining numerical simulation with trajectory simulation was established for the process of store separated from the plane by the second explore technologies of the CFD software(FLUENT)and the RNG k-e turbulence model.The changed flow field caused by the relative motion between the store and the plane was renewed by the method of dynamic mesh.The process of a missile separated from aircraft was simulated under supersonic conditioncoupling the solution of whole field with the solution of 6-DOF equations.The result showed that:1) The aerodynamic interference has great effect on the store's longitudinal motion;and 2) As Mach number increasesthe displacement of dropping decreases and the amplitude of angle of pitching increases.
4 citations
TL;DR: Zhang et al. as discussed by the authors designed a highly reliable, low-cost housekeeping system using industrial devices, which includes dual modular redundancy, CPU warm backup, static triple modular redundancy scheme, and two-level watchdogs.
Abstract: The ZDPS-1A pico-satellite designed in Zhejiang University with a mass of 3.5 kg and a power consumption of less than 3.5 W is the smallest satellite in China up to now. The housekeeping system (HKS) is the core part of ZDPS-1A. The reliability of HKS has an important influence on the safety of the satellite. Traditional fault-tolerant methods do not apply to ZDPS-1A due to such pico-satellite characteristics as light weight, compactness in size, energy saving, and high integration. This paper deals with a highly-reliable, low-cost design for HKS using industrial devices. The reliable strategies of HKS include a dual modular redundancy scheme, CPU warm backup, a static triple modular redundancy scheme, and two-level watchdogs. Recursive experiments, special tests, and environmental tests show that this system meets the design target. This design has already been applied to ZDPS-1A, which was launched to execute in-orbit tasks on Sept. 22, 2010. To date, the satellite has been in a proper state for more than 15 months.
3 citations
01 Jan 2012
TL;DR: In this paper, the effect of temperature on the ballistic limit of woven graphite/epoxy composite panels (6 in. × 4 in., 0.25 in.) at five different temperatures: −60 C, −20 C, R.T, 75 C and 125 C was investigated.
Abstract: This paper investigates the effect of temperature on the ballistic limit of woven graphite/epoxy composite panels (6 in. × 4 in. × 0.25 in.) at five different temperatures: −60 C, −20 C, R.T, 75 C and 125 C. The studies were conducted by combining experimental and 3-D dynamic finite element approaches. The specimens tested were made of plain-weave IM7graphite fibers/toughened epoxy. The composite panels were impacted using an in-house gas gun. The time-histories of impact-induced dynamic strains were recorded. The damaged specimens were inspected visually and using the ultrasonic C scan method. A 3-D dynamic finite element (FE) software, with Chang-Chang composite damage model, was then used to simulate the experimental results of the ballistic impact tests. Good agreement between experimental and FE results has been achieved.
TL;DR: In this paper, it has been widely assumed that Russia has been an ally of the Serbs and that it was in particular an anti-Western supporter of Belgrade during the wars of the 1990s.
Abstract: It has long been widely assumed that Russia has been an ally of the Serbs and that it was in particular an anti-Western supporter of Belgrade during the wars of the 1990s. In fact, Russia, in cahoots with the Western powers and NATO, played a game of deception to make it appear that it was ‘anti-Serbian’ when in reality it acted as ‘errand boy’ in order to fulfill the West's objectives in the former Yugoslavia.
Journal Article•
TL;DR: In this paper, a multi-criteria decision-making method which combines the grey relation projection method, weighted summation method, weighted product method and ideal point decision making is presented, and how to use the integrated method is introduced.
Abstract: In this paper,a multi-criteria decision-making method which combines the grey relation projection method,weighted summation method,weighted product method and ideal point decision making reasonable for unmanned combat aerial vehicle top-layer scheme selection is presented,and how to use the integrated method is introduced.The developed method can deal with evaluation index by different normalized method,to obtain the weights of the evaluation indexes which involve multi-criteria and multi-layers,and the evaluation indices are contacted by the various weights.The best scheme can be found by applying the multi-criteria decision-making approach which combines four multi-criteria decision-making approaches by decision preferences.Finally,the effectiveness and feasibility of the method are validated by using an example of unmanned combat aerial vehicle(UCAV) top-layer scheme selection.
TL;DR: In this article, the authors conclude that Russian leaders have acquiesced to and even supported NATO expansion and that compliance with NATO expansion, Moscow's decision-makers apparently believe, can only promote the pecuniary interests of that group.
Abstract: Of all the assumptions pervading the conventional wisdom about Russian foreign policy few have been more universally accepted than Russia's supposed opposition to NATO expansion. Because Russia's principal source of profit has come from rental value of natural resources from the world market, Russia's foreign policy has largely been conducted in the interests of the exporters of those resources. Compliance with NATO expansion, Moscow's decision-makers apparently believe, can only promote the pecuniary interests of that group. Given this dynamic, and confirmed by an examination of the historical record, I conclude that Moscow's leaders have acquiesced to and even supported NATO expansion.
15 Oct 2012
TL;DR: Based on the sliding mode control theory, the follower controller without the angular acceleration is designed to overcome the problem of information absence and a simulation of four agents flight in the three-dimension space is given to prove its effectiveness.
Abstract: In traditional leader-follower approach, there is no formation feedback from the followers to the leader. If the leader moves too fast, due to the control saturation, the followers will not be able to track the desired position to keep formation. In order to overcome the disadvantage of the leader-follower approach, based on the idea of formation feedback, a leader controller with formation feedback from the followers is designed to guarantee both formation maintenance and formation speed. In general flight, the angular acceleration of the leader can't be obtained by the follower. Based on the sliding mode control theory, the follower controller without the angular acceleration is designed to overcome the problem of information absence. Finally, a simulation of four agents flight in the three-dimension space is given to prove its effectiveness.