Showing papers on "Trojan published in 2004"

Long-term evolution of the Neptune Trojan 2001 QR322

Abstract: Wesimulated more than a hundred possible orbits of the Neptune Trojan 2001 QR322 forthe age of the Solar system. The orbits were generated randomly according to the probabilitydensity derived from the covariance matrix of the orbital elements. The test trajectories libratearound NeptuneOs L 4 point, with amplitudes varying from 40 to 75 and libration periodsvarying from 8900 to 9300 yr. The 18 secular resonance plays an important role. There is aseparatrix of the resonance so that the resonant angle switches irregularly between librationand circulation. The orbits are chaotic, with observed Lyapunov times from 1.7 to 20 Myr,approximately. The probability of escape to a non-Trojan orbit in our simulations was low, andonlyoccurredfororbitsstartingnearthelow-probabilityedgeoftheorbitalelementdistribution(largest values of initial semimajor axis and small eccentricity). This suggests that the Trojanmay well be a primordial object. Key words: celestial mechanics — minor planets, asteroids — Solar system: general.

Transitional and temporary objects in the Jupiter Trojan area

Abstract: I have integrated 1233 objects with semimajor axes between 4.6 and 5.8 AU 1000 years back and forward in time. A search for Jupiter horseshoe Trojans in transition from tadpole orbits to non-Trojan orbits and objects in temporary horseshoe orbits was made. A total of 13 objects (5 comets, 3 asteroids and 5 Trojans) were found. In a second group, among 337 new Trojans discovered after the primary investigation, 7 transitional candidates were found. Two objects, 2000 HR 24 and 2002 GP 31 , are falsely identified as Trojans. No likely transitional objects were found in the first object set, but all of them have at least temporary captures in orbit types associated with Jupiter's 1:1 mean motion resonance. Trojans in the first set have short observational arcs which can explain the low probability for a Trojan past. Trojans in the second set have longer arcs and 5 of them are good candidates for being in transition from the Trojan area.

On the accuracy of restricted three-body models for the trojan motion

Abstract: In this note we compare the frequencies of the motion of the Trojan asteroids in the Restricted Three-Body Problem (RTBP), the Elliptic Restricted Three-Body Problem (ERTBP) and the Outer Solar System (OSS) model. The RTBP and ERTBP are well-known academic models for the motion of these asteroids, and the OSS is the standard model used for realistic simulations. Our results are based on a systematic frequency analysis of the motion of these asteroids. The main conclusion is that both the RTBP and ERTBP are not very accurate models for the long-term dynamics, although the level of accuracy strongly depends on the selected asteroid.

Jupiter's outer satellites and Trojans

Abstract: Jupiter’s irregular satellites possess large, eccentric and highly inclined orbits. They are conventionally considered separately from the temporarily captured satellites and the Trojans (the latter co-orbiting the Sun leading and trailing Jupiter by 60◦). However, there is reason to believe that objects in these three groups share many similarities, both in terms of their physical properties and their origins. Accordingly, in this review we jointly discuss the irregular and temporary satellites and the Trojans. In the modern view of the solar system, different populations of small bodies can be traced back to their origin in the protoplanetary disk of the Sun. Most planetesimals that formed near the orbits of the giant planets were promptly ejected from the planetary region. A small fraction of those ejected (perhaps 10%) remain bound to the Sun in the ∼ 10 AU scale Oort Cloud which provides a continuing source of the long-period comets. Planetesimals growing beyond Neptune were relatively undisturbed and their descendants survive today in the Kuiper Belt . The Kuiper Belt in turn feeds the giant-planet crossing Centaurs , which are then converted by planetary (largely Jovian) perturbations into Jupiter Family Comets (JFCs; short-period comets which are strongly interacting with Jupiter, formally those with Tisserand invariants 2 ≤ T ≤ 3). During their interaction with Jupiter, the comets sometimes become temporarily trapped. Main-belt asteroids near resonances with Jupiter can also be excited into Jupiter-crossing orbits, and may contribute to the populations of temporarily trapped objects. Since there is currently no effective source of energy dissipation, neither the temporary satellites nor the Trojan librators can be captured as permanent members of these populations. Temporary members will be either flung out of the jovian system or impact the planet or one of the Galilean satellites. However, at very early epochs, at the end of Jupiter’s ≤ 10 to ≤ 10 yr growth phase, several mechanisms might have operated to permanently trap objects from these and other reservoirs. Therefore, populations which are not now interacting may once have been so. Given the dynamical interrelations (Figure 12.1), it is to be expected that Figure 12.1. Interrelations among the populations considered in this chapter. Solid arrows denote established dynamical pathways. At the present epoch, in which sources of energy dissipation are essentially absent, no known pathways (dashed lines) exist between the temporary and permanent satellite and Trojan populations. Numbers in parentheses indicate the approximate dynamical lifetimes of the different populations.

Optimum trajectory for low-thrust multiple Trojan asteroid flybys

Abstract: It is known that there is an asteroid family around L4 or L5 Lagrange point of the Sun-Jupiter system, and it is called the Trojan asteroid family. As one of outer planet exploration mission, a plan to explore the Trojan asteroids using Jupiter swing-by is considered. Based on this mission, this paper discusses multiple flybys trajectory for Trojan asteroids exploration. A trajectory optimization of Trojan asteroids exploration using multiple flybys depends largely on objects of exploration. For this reason, the stage of choosing the candidates of exploration is important, and it is indispensable to choose most qualified candidate for the mission. As the first step, this paper proposes the flyby sequence search strategy which uses a ballistic orbit, and using these results, the multiple flybys trajectory to Trojan asteroids by impulsive velocity change is designed. Next, this paper considers an optimization of multiple slow-flybys trajectory of the spacecraft which uses low thrust propulsion. Furthermore feasibility of the sequence of main-belt asteroid flyby on the way to Trojan asteroid was studied.

Research on the concealing technology of Trojan horses

Abstract: Based on the study of the concealing technology of Trojan horses on Linux system, this paper presents an idea of cooperative concealment between Trojan horses and also gives its formal model. Today抯 Trojan horses lack the abilities to cope with real-time detection and have poor performance in hiding network communication. The kernel Trojan horse prototype uses anti-real-time detection techniques and network covert channels to enhance its abilities of concealment. It is the embodiment of the idea of cooperative concealment. The experiment results show it has verified the validity of the techniques of avoiding real-time detection and network covert channels.

A self-checking signature scheme for checking backdoor security attacks in internet

Abstract: It is very common for people across the globe to collaborate on the Internet and intellectual Property amongst each other. A serious threat to this form of collaboration can come from "backdoor" attacks from hackers, who can distort the information content. For example. a backdoor attack may replace common operating system functions with malicious ones. A possible precaution against such an attack is to generate a signature database and compare the signature of a system functionality with its golden signature before using the functionality. We present an alternate and novel method to detect Trojan activity. Called time fingerprinting, the method relies on observing a finite number of fingerprints during signature generation and tracing the Trojan fingerprints in systems files. We have verified the desired properties using common semi trusted operating system files.

Methods for cluster-based incident detection

Abstract: Here, we introduce a statistics-based anomaly detection technique for identifying systems that could have been compromised and had trojan executables installed. Attackers frequently install rootkits and other trojan files onto hosts they compromise so they can easily gain access in the future. Many detection systems use signatures to identify unauthorized files, but signatures for all platforms and patch levels do not exist in large-scale environments, such as government and university networks. Our anomaly detection system organizes hosts into clusters based on their files and uses statistics to identify those that should be examined in more detail.

Global Institutions in Local Decision-Making: The Trojan Horses of the New Millennium?

Abstract: Alexander, N. (2001) ‘Short Comment on Conditionality’, in IMF (ed.) External Comments and Contributions on IMF Conditionality, September, Washington DC, http://www.imf.org/external/np/pdr/cond/2001/eng/collab/comment.pdf Bateson, G., Jackson, D.D., Haley, J. and Weakland, J.H. (1956) ‘Towards a Theory of Schizophrenia’, Behavioural Science 1: 251–64. Booth, D. (2003) ‘Introduction and Overview’, Development Policy Review 21(2): 131–59. Gore, C. (2003) ‘Development Partnership for Escaping the Global Poverty Trap’, Development Policy Journal 3: 107–26. OECD (1996) Shaping the 21st Century: The Contribution of Development Cooperation. Paris: OECD. OECD (2000) Development Cooperation 1999 Report. Paris: OECD. UNCTAD (2000) The Least Developed Countries Report 2000. New York and Geneva: United Nations. UNCTAD (2002) The Least Developed Countries Report 2002: Escaping the Poverty Trap. New York and Geneva: United Nations. UNCTAD (2004) The Least Developed Countries Report 2004: Linking International Trade with Poverty Reduction. New York and Geneva: United Nations.

Studying binary asteroids with NGS and LGS AO systems

Abstract: Since the discovery of Dactyl orbiting around Ida by the Galileo spacecraft in 1993, over twenty-five binary asteroid systems have been discovered using radar, direct imaging and Adaptive Optics observations. Asteroidal moon discoveries dramatically increased with the advent of this last technique on ground based telescopes. Our group focuses on the search and study of double asteroids in the main-belt, in the Trojan population and beyond Neptune's orbit. We have been using several of the AO systems available (Lick-3m, Palomar-5m, VLT-8m, Keck-10m) and related techniques such as Appulse and Laser Guide Star observations to broaden the sample of asteroids observed from the main-belt out to the Kuiper Belt. We will present a quality comparison between various techniques and different AO systems with NGS and will detail our first successful observations with the Lick LGS system. Precise orbital elements of the secondary can be determined by multiple observations spanning large periods of time (several months). Our group developed a method to predict the ephemeris of a secondary companion. Without any assumptions, this method, tested successfully on 22 Kalliope and 121 Hermione binary systems, leads to the direct determination of important physical parameters of the targets, such as their mass and the interior structure, as well as gives direct insights on their formation processes that may be otherwise only be speculated on from spacecraft mission flybys.

The Trojan Epic: Posthomerica

Abstract: Composed in the third century A.D., the Trojan Epic is the earliest surviving literary evidence for many of the traditions of the Trojan War passed down from ancient Greece. Also known as the Posthomerica, or "sequel to Homer," the Trojan Epic chronicles the course of the war after the burial of Troy's greatest hero, Hektor. Quintus, believed to have been an educated Greek living in Roman Asia Minor, included some of the war's most legendary events: the death of Achilles, the Trojan Horse, and the destruction of Troy. But because Quintus deliberately imitated Homer's language and style, his work has been dismissed by many scholars as pastiche. A vivid and entertaining story in its own right, the Trojan Epic is also particularly significant for what it reveals about its sources-the much older, now lost Greek epics about the Trojan War known collectively as the Epic Cycle. Written in the Homeric era, these poems recounted events not included in the Iliad or the Odyssey. As Alan James makes clear in this vibrant and faithful new translation, Quintus's work deserves attention for its literary-historical importance and its narrative power. James's line-by-line verse translation in English reveals the original as an exciting and eloquent tale of gods and heroes, bravery and cunning, hubris and brutality. James includes a substantial introduction which places the work in its literary and historical context, a detailed and annotated book-by-book summary of the epic, a commentary dealing mainly with sources, and an explanatory index of proper names. Brilliantly revitalized by James, the Trojan Epic will appeal to a wide range of readers interested in Greek mythology and the legend of Troy.

Jonathan Burgess, The Tradition of the Trojan War in Homer & the Epic Cycle

Abstract: Letoublon Francoise. Jonathan Burgess, The Tradition of the Trojan War in Homer & the Epic Cycle. In: Gaia : revue interdisciplinaire sur la Grece Archaique, numero 8, 2004. pp. 195-199.

Nekhoroshev stability estimates for different models of the Trojan asteroids

Abstract: Estimates of the region of Nekhoroshev stability of Jupiter's Trojan asteroids are obtained by a direct (i.e. without use of the normal form) construction of formal integrals near the Lagrangian elliptic equilibrium points. Formal integrals are constructed in the Hamiltonian model of the planar circular restricted three body problem (PCRTBP), and in a mapping model (Sandor et al. 2002) of the same problem for small orbital eccentricities of the asteroids. The analytical estimates are based on the calculation of the size of the remainder of the formal series by a computer program. An analysis is made of the accumulation of small divisors in the series. The most important divisors introduce competing Fourier terms with sizes growing at similar rates as the order of truncation increases. This makes impossible to improve the estimates by considering nearly resonant forms of the formal integrals for particular near-resonances. Improved estimates were obtained in a mapping model of the PCRTBP. The main source of improvement is the use of better variables (Delaunay). Our best estimate represents a maximum libration amplitude . This is a quite realistic value which demonstrates the usefulness of Nekhoroshev theory.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Asteroid proper elements: recent computational progress

Abstract: In this work, we review the analytical and semi-analytical tools introduced to deal with resonant proper elements and their applications to the Trojan asteroids, the numerical computation of synthetic proper elements for resonant and non resonant asteroids, and the introduction of proper elements for planet crossing asteroids. We discuss the applications and accuracy of these methods and present some comparisons between them.

Personal Firewall Based on APIHOOK Technology

Abstract: The application programming interface HOOK (APIHOOK) te chnology and its realization in personal firewalls are discussed and the behavio r characteristics of Trojans are analyzed. Based on the APIHOOK technology and a iming at the behavior of Trojans the personal firewall is developed. The basic i dea of the personal firewall is displacing certain API functions of the system D LL developed by us. The new API functions can monitor all the operations to reg istration table, file creation, network connection and communication port, and o ther advanced operations. Once a behavior like Trojan′s is detected, the firewa ll informs the users and response timely according to the rules, which can be cu s tomized by the users. As the firewall can record the behavior of all the program s in detail, the advanced users can analyze the behavior of Trojans. The firewal l is capable of guarding against known or any unknown Trojan for its behavior se nsitive. Attacks from a collection of the real Trojans are initiated to test the personal firewall′s performance. Results indicate that the firewall guards the kno wn or any unknown Trojans.

Scob Attack: A Sign of Bad Things to Come?

Abstract: A recent Internet attack that exploited a powerful new assault technique has computer security officials worried that it could be a harbinger of worse things to come. The attack was based on a Trojan horse - a nonreplicating program that hides malicious code inside apparently harmless programming, data, or Web pages - dubbed JS.Scob.Trojan by antivirus experts. These servers hosted millions of infected pages during the attack. Scob affected Web sites for such well-known organizations as the Kelley Blue Book car pricing service and MinervaHealth, which provides online financial services for the healthcare industry. The Trojan loaded software that captured victims' keystrokes - which could have included valuable information such as passwords and credit card numbers - and sent them back to the hackers. The Scob attack was significant for several reasons. Scob's dangerous new aspect was that rather than opening e-mail attachments, victims didn't have to do anything but visit a contaminated Web site to become infected. By using Web servers and Web sites to install the malicious code, hackers were able to install the Trojan.