Showing papers on "Trojan published in 2003"
TL;DR: In this article, the authors present radiometrically derived V-band geometric albedos and effective radii for 32 Jovian Trojan asteroids, using near-simultaneous mid-infrared and visible observations.
Abstract: We present radiometrically derived V-band geometric albedos and effective radii for 32 Jovian Trojan asteroids, using near-simultaneous mid-infrared and visible observations. We sampled the large end of the group’s size distribution, down to a radius of 25 km, using 14 objects in the L4 swarm and 18 in the L5 swarm. We find that the albedo distribution is much narrower than previously derived from IRAS measurements. The Trojans, for the most part, have very similar albedos. The actual mean and standard deviation of the distribution depend on the average Trojan beaming parameter � . The ‘‘ standard ’’ value of 0.756, which was used for the IRAS analysis, yields a mean albedo of 0.056 � 0.003 and a standard deviation of 0.009. However, a value of � = 0.94, which we found represented our data better, yields 0.041 � 0.002 and a standard deviation of just 0.007. The thermal behavior of the Trojans seems to follow the ‘‘ slow rotator ’’ model, and the thermal inertia itself can be no greater than about half the Moon’s value. The Kolmogorov-Smirnov test was used to compare the Trojans’ albedo distribution with that of cometary nuclei, dead-comet candidates, and outer solar system objects. We find that the Trojan distribution is similar only to the cometary ones, and only if the Trojans’ � � 1. Observations of the binary (617) Patroclus reveal that its albedo is rather typical among the distribution. We have also discovered that (4709) Ennomos has an extremely elevated albedo, about 0.15. This object may have a very unusual thermal behavior or have recently suffered a large impact that excavated the surface down to a layer of highly reflective, pristine ice.
138 citations
TL;DR: In this article, the authors report on the occupation of the 1 : 1 (Trojan), 4 : 3, 3 : 2, 7 : 4, 2 : 1, and 5 : 2 Neptunian mean motion resonances (MMRs).
Abstract: As part of our ongoing Deep Ecliptic Survey (DES) of the Kuiper belt, we report on the occupation of the 1 : 1 (Trojan), 4 : 3, 3 : 2, 7 : 4, 2 : 1, and 5 : 2 Neptunian mean motion resonances (MMRs). The previously unrecognized occupation of the 1 : 1 and 5 : 2 MMRs is not easily understood within the standard model of resonance sweeping by a migratory Neptune over an initially dynamically cold belt. Among all resonant Kuiper belt objects (KBOs), the three observed members of the 5 : 2 MMR discovered by DES possess the largest semimajor axes (a ≈ 55.4 AU), the highest eccentricities (e ≈ 0.4), and substantial orbital inclinations (i ≈ 10°). Objects (38084) 1999HB12 and possibly 2001KC77 can librate with modest amplitudes of ~90° within the 5 : 2 MMR for at least 1 Gyr. Their trajectories cannot be explained by close encounters with Neptune alone, given the latter's current orbit. The dynamically hot orbits of such 5 : 2 resonant KBOs, unlike hot orbits of previously known resonant KBOs, may imply that these objects were preheated to large inclination and large eccentricity prior to resonance capture by a migratory Neptune. Our first discovered Neptunian Trojan, 2001QR322, may not owe its existence to Neptune's migration at all. The trajectory of 2001QR322 is remarkably stable; the object can undergo tadpole-type libration about Neptune's leading Lagrange (L4) point for at least 1 Gyr with a libration amplitude of 24°. Trojan capture probably occurred while Neptune accreted the bulk of its mass. For an assumed albedo of 12%–4%, our Trojan is ~130–230 km in diameter. Model-dependent estimates place the total number of Neptune Trojans resembling 2001QR322 at ~20–60. Their existence helps to rule out violent orbital histories for Neptune.
136 citations
TL;DR: The form of lamentation in Greek tragedy has been identified as a gendered genre in the Trojan Women as discussed by the authors, and the authors of this paper apply these criteria to the Trojan women and conclude that virtually every scene in the play shows the characteristics of lament.
Abstract: This article summarizes the findings of an unpublished PhD dissertation, "The Form of Lament in Greek Tragedy" by E Wright, which provide for the first time objective criteria for identification of lamentation in tragedy It applies these criteria to the Trojan Women , and argues, on the basis of metrical and stylistic devices, that virtually every scene in the Trojan Women shows the characteristics of lament The play is, from both the minute technical, and the overall structural, point of view, a lament This provides explanations for some of the long-standing critical issues of the play, eg, no unity, no plot, an ill-conceived prologue The article then considers also how the Trojan Women fits into current discussions of lament as a gendered genre It replies especially to work on the development of 5th-century Athenian attitudes towards female lament, in which a pattern of increased criticism and restriction, it is argued, is reflected in the changing treatment of lament in Athenian tragedy The treatment of lament in the Trojan Women does not conform to this perceived development This suggests that there were still a variety of attitudes current and influential in late 5th-century Athens towards female lamentation
49 citations
TL;DR: In this article, the stability properties of Trojan-type orbits in the proximity of the L 4 and L 5 Lagrangian points of Jupiter were investigated using the frequency map analysis (FMA) method.
Abstract: Using the frequency map analysis (FMA) method we investigate the stability properties of Trojan-type orbits in the proximity of the L 4 and L 5 Lagrangian points of Jupiter. This study is part of the MATROS project. The orbits of about 2 x 10 4 virtual Trojans with random initial conditions have been computed numerically and for each body the diffusion rate in frequency space has been determined by spectral analysis. The diffusion portraits show where stable orbits are located in the space of proper elements for different values of inclination. For low inclined orbits we reproduce the stability region outlined by Levison, Shoemaker & Shoemaker and, due to our fast sampling capability, we find additional resonant features in the libration amplitude versus proper eccentricity space. At higher inclinations, the stability region gradually shrinks and it disappears for inclinations of about 40°. The maximal Lyapunov characteristic exponent is computed for a limited number of Trojan orbits in our sample and the predictions concerning the chaotic behaviour of each orbit are compared with those given by the FMA method. A good agreement is obtained and the value of the Lyapunov exponent may be used to tune the results of the FMA analysis. A synthetic secular theory for the proper frequencies of Jupiter Trojans is obtained by numerically fitting the outcome of the frequency map analysis.
48 citations
TL;DR: In this article, an analysis of the long term stability of Trojan type orbits of both Uranus and Neptune has been presented by employing the Frequency Map Analysis (hereinafter FMA) method.
Abstract: We present in this paper an analysis of the long term stability of Trojan type orbits of both Uranus and Neptune. Employing the Frequency Map Analysis (hereinafter FMA) we measure the diffusion speed in the phase space for a large sample of Trojan orbits with short numerical integrations. High resolution diffusion maps are derived for different values of initial inclination. These maps outline where the most stable orbits can be found in the Trojan clouds of the two planets. The orbit of the newly discovered Neptune Trojan 2001 QR322 has been analysed in detail with the FMA method. In the phase space the body is located close to the border of a stable region for low inclination Neptune Trojans. Numerical integrations over 4.5 Gyr of clone orbits generated from the covariance matrix show that only 10% of the clones escape from the Trojan cloud. The proper frequencies of the Trojan motion computed with the FMA algorithm allow us to to derive a numerical secular theory. From this theory it is possible to locate in the phase space the main secular resonances that can perturb Trojan orbits of the two planets and lead to instability.
47 citations
01 Jan 2003
TL;DR: A theory based on granulation that has captured the essence of BN’s intuitive idea, Chinese wall security policy model, and the results are more than the Chinese wall models: Malicious Trojan horses in certain DAC Model (discretionary access control) can be controlled or confined.
Abstract: In 1989, Brewer and Nash (BN) presented a fascinating idea, called Chinese wall security policy model, for commercial security. Their idea was based on the analysis of the notion, Conflict of Interest binary Relation (CIR). Unfortunately, their formalization did not fully catch the appropriate properties of CIR. In this paper, we present a theory based on granulation that has captured the essence of BN’s intuitive idea. The results are more than the Chinese wall models: Malicious Trojan horses in certain DAC Model (discretionary access control) can be controlled or confined.
34 citations
TL;DR: The spectral differences among the Mars Trojans suggests that either they did not all form at their current solar distances or that they have not always been at their present sizes as mentioned in this paper.
33 citations
TL;DR: In this paper, the authors review ongoing efforts to identify occupants of mean-motion resonances and collisional families in the Edgeworth-Kuiper belt and find that resonant KBOs typically have large orbital eccentricities and inclinations, consistent with resonant capture and adiabatic excitation by a migratory Neptune.
Abstract: We review ongoing efforts to identify occupants of mean-motion resonances (MMRs) and collisional families in the Edgeworth—Kuiper belt. Direct integrations of trajectories of Kuiper belt objects (KBOs) reveal the 1:1 (Trojan), 5:4, 4:3, 3:2 (Plutino), 5:3, 7:4, 9:5, 2:1 (Twotino), and 5:2 MMRs to be inhabited. Apart from the Trojan, resonant KBOs typically have large orbital eccentricities and inclinations. The observed pattern of resonance occupation is consistent with resonant capture and adiabatic excitation by a migratory Neptune; however, the dynamically cold initial conditions prior to resonance sweeping that are typically assumed by migration simulations are probably inadequate. Given the dynamically hot residents of the 5:2 MMR and the substantial inclinations observed in all exterior MMRs, a fraction of the primordial belt was likely dynamically pre-heated prior to resonance sweeping. A pre-heated population may have arisen as Neptune gravitationally scattered objects into trans-Neptunian space. The spatial distribution of Twotinos offers a unique diagnostic of Neptune’s migration history. The Neptunian Trojan population may rival the Jovian Trojan population, and the former’s existence is argued to rule out violent orbital histories for Neptune. Finally, lowest-order secular theory is applied to several hundred non-resonant KBOs with well-measured orbits to update proposals of collisional families. No convincing family is detected.
31 citations
Patent•
28 Apr 2003
TL;DR: In this article, a network security system and method for reacting to unauthorized data access in an inner data system by combining a redirect system is described, which includes modified firewalls, IP sharing devices and gateways with examining mechanism.
Abstract: A network security system and method for reacting to unauthorized data access in an inner data system by combining a redirect system is described. The examples of the redirect system include modified firewalls, IP sharing devices and gateways with examining mechanism. A user request is transmitted to the inner data system via the redirect system if the user request satisfies a certain safety condition. Otherwise, the user request is transmitted to a reaction system which provides virtual data similar to real data so that unauthorized users have the illusion of successfully hacking the inner data system. Meanwhile, the illegal activities are recorded and certain programs like Trojan programs can be used for executing reactions.
23 citations
18 Jun 2003
TL;DR: The terms used today to categorise different types of software weapons are not really suitable, because there exist several different definitions of each term, many of them contradicting each other, so some methods for solving the problem are presented.
Abstract: The terms used today to categorise different types of software weapons are not really suitable, because there exist several different definitions of each term, many of them contradicting each other. Therefore we present some methods for solving the problem. All the methods are based on a technical description's model of IT weapons (TEBIT), which is a proposed taxonomy of software weapons. Two methods, a weapon-based and a definition-based, are evaluated empirically and the results and experiences are discussed, leading to the recommendation of the weapon-based method.
17 citations
Posted Content•
TL;DR: In this article, the authors review ongoing efforts to identify occupants of mean motion resonances (MMRs) and collisional families in the Edgeworth-Kuiper belt.
Abstract: We review ongoing efforts to identify occupants of mean-motion resonances (MMRs) and collisional families in the Edgeworth-Kuiper belt. Direct integrations of trajectories of Kuiper belt objects (KBOs) reveal the 1:1 (Trojan), 5:4, 4:3, 3:2 (Plutino), 5:3, 7:4, 9:5, 2:1 (Twotino), and 5:2 MMRs to be inhabited. Apart from the Trojan, resonant KBOs typically have large orbital eccentricities and inclinations. The observed pattern of resonance occupation is consistent with resonant capture and adiabatic excitation by a migratory Neptune; however, the dynamically cold initial conditions prior to resonance sweeping that are typically assumed by migration simulations are probably inadequate. Given the dynamically hot residents of the 5:2 MMR and the substantial inclinations observed in all exterior MMRs, a fraction of the primordial belt was likely dynamically pre-heated prior to resonance sweeping. A pre-heated population may have arisen as Neptune gravitationally scattered objects into trans-Neptunian space. The spatial distribution of Twotinos offers a unique diagnostic of Neptune's migration history. The Neptunian Trojan population may rival the Jovian Trojan population, and the former's existence is argued to rule out violent orbital histories for Neptune. Finally, lowest-order secular theory is applied to several hundred non-resonant KBOs with well-measured orbits to update proposals of collisional families. No convincing family is detected.
TL;DR: In this paper, the authors report on the occupation of the 1:1 (Trojan), 4:3, 3:2, 7:4, 2:1, and 5:2 Neptunian mean-motion resonances (MMRs).
Abstract: As part of our ongoing Deep Ecliptic Survey (DES) of the Kuiper belt, we report on the occupation of the 1:1 (Trojan), 4:3, 3:2, 7:4, 2:1, and 5:2 Neptunian mean-motion resonances (MMRs). The occupation of the 1:1 and 5:2 MMRs is not easily understood within the standard model of resonance sweeping by a migratory Neptune over an initially dynamically cold belt. Our dynamically hot, 5:2 resonant objects can librate with modest amplitudes of 90 deg within the resonance for at least 1 Gyr. Their trajectories cannot be explained by close encounters with Neptune alone, given the latter's current orbit. The hot orbits of such 5:2 resonant KBOs, unlike hot orbits of previously known resonant KBOs, may imply that these objects were pre-heated to large inclination and large eccentricity prior to resonance capture by a migratory Neptune. Our first discovered Neptunian Trojan, 2001QR322, may not owe its existence to Neptune's migration at all. The trajectory of 2001QR322 is remarkably stable; the object can undergo tadpole-type libration about Neptune's leading Lagrange (L4) point for at least 1 Gyr with a libration amplitude of 24 deg. Trojan capture probably occurred while Neptune accreted the bulk of its mass. For an assumed albedo of 12--4%, our Trojan is 130--230 km in diameter. Model-dependent estimates place the total number of Neptune Trojans resembling 2001QR322 at 20--60. Their existence might rule out violent orbital histories for Neptune.
Journal Article•
03 Nov 2003
TL;DR: Unlike the synchronous and static marker passing algorithm previously used for parallel semantic network design, the TROJAN operates asynchronously, supporting knowledge sharing, dynamic load balancing and duplicate checking.
Abstract: This paper describes a new parallel semantic network system, the TROJAN. Unlike the synchronous and static marker passing algorithm previously used for parallel semantic network design, the TROJAN operates asynchronously, supporting knowledge sharing, dynamic load balancing and duplicate checking. Current implementation of the TROJAN focuses on path-based knowledge inferences, using ANSI C and the MPICH-G2 with flex lexical analyzer and the yacc parser generator. The performance tests have been carried out on a local Grid, consisting of three heterogeneous systems: a SUN Cluster, an SGI Origin 3800, and a Dell Pentium cluster. The experiments demonstrate promising speedups.
20 Aug 2003
TL;DR: Linear dynamically varying (LDV) control is a technique for getting a natural (nonlinear, possibly chaotic) trajectory and a perturbed trajectory asymptotically synchronized given an initial condition offset.
Abstract: Linear dynamically varying (LDV) control is a technique for getting a natural (nonlinear, possibly chaotic) trajectory and a perturbed trajectory asymptotically synchronized given an initial condition offset. Probably the best illustrative example, which motivates this paper, is tracking the natural (possibly quasi-periodic) motion of a Trojan asteroid near the L4 point of Jupiter with a spacecraft that follows a trajectory perturbed by the non conservative propulsion forces. The tracking error is linearized around the natural dynamics of the Trojan body, leading to an LDV model of the tracking error. This in turn leads to a dynamically varying controller, itself given as the solution to a Partial Differential Riccati Equation, solved via the method of characteristics. It is shown that this technique allows for accurate tracking of the complicated dynamics around the L4 point.
Patent•
13 May 2003
TL;DR: In this paper, the CRC values of the routines of known Trojan Horses are gathered in a database, and a stage in which indicating an executable as Trojan Horse is carried out by the correspondence of the CRC value of the program routines of said executable to the known Trojan horse values, as gathered in said database.
Abstract: A method and system for indicating an executable as Trojan Horse, based on the CRC values of the routines of an executable. The method comprising a preliminary stage in which the CRC values of the routines of known Trojan Horses are gathered in a database, and a stage in which indicating an executable as Trojan Horse is carried out by the correspondence of the CRC values of the routines of said executable to the CRC values of the known Trojan Horses, as gathered in said database. The system comprising means for calculating the CRC values of routines; means for identifying the borders of the routines of an executable; a database system, for storing the CRC values of routines of known Trojan Horses; and means for determining the correspondence between two groups of CRC values, thereby enabling detection of the correspondence of an executable to at least one known Trojan Horse.
01 May 2003
TL;DR: In this article, the authors detected 51 faint Jovian Trojan asteroids in the L4 Lagrangian swarm in survey observations near opposition and the ecliptic using a wide-field mosaicked CCD camera on the 8.2 m Subaru Telescope.
Abstract: We detected 51 faint Jovian Trojan asteroids in the L4 Lagrangian swarm in survey observations near opposition and the ecliptic using a wide-field mosaicked CCD camera on the 8.2 m Subaru Telescope. We report the Trojan size distributions in this paper. The surveyed sky area was about 3 deg2 and located ~30° in longitude ahead of the L4 point. From trailed-image simulations of hypothetical Trojans, we measured the 90% complete detection limiting magnitudes for our Trojan asteroids on a CCD chip-by-chip basis. The limiting magnitudes varied by 0.4–0.5 mag between chips; therefore, we introduce a new measure of detection limit appropriate for multichip CCD cameras. By statistically comparing the observed number of Trojans with the predictions from theoretical size distributions near the limiting magnitude calculated in this way, we determined a limiting diameter of D ~ 2 km, corresponding to the detection limit of this survey. On the other hand, the detected Trojans covered a size range of 0.7 km 1 km. Finally, we discuss, from a cosmogonic viewpoint, a possible relation between Trojans and short-period comets on the basis of their size distribution slopes.
TL;DR: In the wake of the Caffrey trial verdict I felt compelled to write an opinion piece on what this verdict and, in particular the style of defence, means for the information security community.
Abstract: In the wake of the Caffrey trial verdict I felt compelled to write an opinion piece on what this verdict and, in particular the style of defence, means for the information security community Aaron Caffrey was accused of launching an attack on a major US port but blamed a Trojan horse controlled by another hacker for the wrongdoing and subsequent deletion of all trace of the Trojan on the PC
01 Jan 2003
TL;DR: In this article, the authors focus on the dynamics of a small particle near the triangular points of the Sun-Jupiter system and develop spec c models based on the numerical computation of periodic and quasi-periodic (with two frequencies) solutions of the planar three body problem.
Abstract: We focus on the dynamics of a small particle near the triangular points of the
Sun-Jupiter system. To try to account for the efect of Saturn (and to simulate in
a more realistic way the Sun-Jupiter relative motion), we develop spec c models
based on the numerical computation of periodic and quasi-periodic (with two fre-
quencies) solutions of the planar three body problem Sun-Jupiter-Saturn and write
them as perturbations of the Sun-Jupiter RTBP.
TL;DR: In this paper, the results of the numerical integration of equations of motion of a infinitesimal mass pleased in the neighborhood of the triangular point of the Sun-planet system are presented.
Abstract: The present paper demonstrates the results of the numerical integration of equations of motion of a infinitesimal mass pleased in the neighborhood of the triangular point of the Sun-planet system. There are presented the results for the outer solar system, i.e. for Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. The long-periodic solutions were searched for the distance from the Lagrangian point changing from ±0.01 to ±0.10 in canonical units. The Trojans of those planets have the circle, tadpole, horseshoe and irregular shape of their orbits. Same of those test particles showed a close approach to planet. Other of those collided with planet and then was removed from the solar system. The tadpole, circle and same trajectories surveyed integration for 100,000 years.