On Detection of Erratic Arguments

Abstract. Due to the erratic nature, the value of a function argument in one normal program execution could become illegal in another normal execution context. Attacks utilizing such erratic arguments are able to evade detections as fine-grained context information is unavailable in many existing detection schemes. In order to obtain such fine-grained context information, a precise model on the internal program states has to be built, which is impractical especially monitoring a closed source program alone. In this paper, we propose an intrusion detection scheme which builds on two diverse programs providing semantically-close functionality. Our model learns underlying semantic correlation of the argument values in these programs, and consequently gains more accurate context information compared to existing schemes. Through experiments, we show that such context information is effective in detecting attacks which manipulate erratic arguments with comparable false positive rates. Key words: Intrusion detection, system call argument, diversity

Supernovae 2016bdu and 2005gl, and their link with SN 2009ip-like transients: another piece of the puzzle

Supernova (SN) 2016bdu is an unusual transient resembling SN 2009ip. SN 2009ip-like events are characterized by a long-lasting phase of erratic variability which ends with two luminous outbursts a few weeks apart. The second outburst is significantly more luminous (about 3 mag) than the first. In the case of SN 2016bdu, the first outburst (Event A) reached an absolute magnitude M(r) ~ -15.3 mag, while the second one (Event B) occurred over one month later and reached M(r) ~ -18 mag. By inspecting archival data, a faint source at the position of SN 2016bdu is detectable several times in the past few years. We interpret these detections as signatures of a phase of erratic variability, similar to that experienced by SN 2009ip between 2008 and mid-2012, and resembling the currently observed variability of the luminous blue variable SN 2000ch in NGC 3432. Spectroscopic monitoring of SN 2016bdu during the second peak initially shows features typical of a SN IIn. One month after the Event B maximum, the spectra develop broad Balmer lines with P Cygni profiles and broad metal features. At these late phases, the spectra resemble those of a typical Type II SN. All members of this SN 2009ip-like group are remarkably similar to the Type IIn SN 2005gl. For this object, the claim of a terminal SN explosion is supported by the disappearance of the progenitor star. The similarity with SN 2005gl suggests that all members of this family may finally explode as genuine SNe, although the unequivocal detection of nucleosynthesised elements in their nebular spectra is still missing.Comment: Submitted to MNRAS on April 10, 2017; re-submitted on June 23 including suggestions from the referee. 24 pages, 12 figures, 5 table

Experimental Simulations and Tort Reform: Avoidance, Error and Overreaching in Sunstein Et Al.’s ‘Punitive Damages’

This article addresses tort reform claims made in Cass R. Sunstein, et al.\u27s Punitive Damages: How Juries Decide (2002)and related articles, research that was largely underwritten by the Exxon Corporation. Based upon a series of simulation experiments, those authors have made a general claim that juries are incapable of making coherent judgments about punitive damages. In this article I raise serious methodological problems bearing on the validity of the research, and, therefore, its ability to provide judges and legislators with useful information about juries and punitive damages

A Persistent Disk Wind in GRS 1915+105 with NICER

The bright, erratic black hole X-ray binary GRS 1915+105 has long been a target for studies of disk instabilities, radio/infrared jets, and accretion disk winds, with implications that often apply to sources that do not exhibit its exotic X-ray variability. With the launch of NICER, we have a new opportunity to study the disk wind in GRS 1915+105 and its variability on short and long timescales. Here we present our analysis of 39 NICER observations of GRS 1915+105 collected during five months of the mission data validation and verification phase, focusing on Fe XXV and Fe XXVI absorption. We report the detection of strong Fe XXVI in 32 (>80%) of these observations, with another four marginal detections; Fe XXV is less common, but both likely arise in the well-known disk wind. We explore how the properties of this wind depends on broad characteristics of the X-ray lightcurve: mean count rate, hardness ratio, and fractional RMS variability. The trends with count rate and RMS are consistent with an average wind column density that is fairly steady between observations but varies rapidly with the source on timescales of seconds. The line dependence on spectral hardness echoes known behavior of disk winds in outbursts of Galactic black holes; these results clearly indicate that NICER is a powerful tool for studying black hole winds.Comment: Accepted for publication in ApJL. Comments welcom

Forward-Looking Echoic Flow for Guidance of an Unmanned Aerial System

Echoic flow is a formula derived from natural phenomena that has the potential to control vehicles with great efficiency using range information. Initially studied in bats, echoic flow allows animals to use sonar as a navigation tool. Downward-facing echoic flow used in the vertical landing of an Unmanned Aerial System (UAS) has been studied in past research. Forward-looking echoic flow on a UAS could allow for new approaches to braking and following techniques in the horizontal plane of motion towards both fixed and moving targets. The goal of this project was to demonstrate forward-looking echoic flow guidance towards a fixed target using a quadcopter and to gather data showing the accuracy and precision of the process. In initial forward-looking tests, a modified Parrot AR Drone with an added ultrasonic sensor and Raspberry Pi were used as the UAS. Preliminary findings showed erratic and often inaccurate range finding measurements. These measurements were attributed in part to the inability of the UAS to aim directly at the small target. A software filter was designed to minimize the impact of erroneous measurements. Further tests conducted using a flat wall as the approach target still yielded trials that did not follow the ideal echoic flow approach accurately. In an attempt to improve the performance of trials, the equation used to convert velocities to motor thrust values was recalibrated. Though trial results did improve due to this modification, imprecise quadcopter movement control prevented the achievement of a smooth echoic flow approach. Finally, simulations of forward-looking trials were performed to test the impact of measurement and velocity error on the performance of echoic flow approaches. The values of measurement error that resulted in acceptable echoic flow performance were found to be lower than the expected values for the UAS in this study. Further forward-looking echoic flow research is recommended using a more accurate and robust rangefinder. A UAS capable of more precise horizontal plane movement is also recommended.No embargoAcademic Major: Electrical and Computer Engineerin

From eye to machine: shifting authority in color measurement

Given a subject so imbued with contention and conflicting theoretical stances, it is remarkable that automated instruments ever came to replace the human eye as sensitive arbiters of color specification. Yet, dramatic shifts in assumptions and practice did occur in the first half of the twentieth century. How and why was confidence transferred from careful observers to mechanized devices when the property being measured – color – had become so closely identified with human physiology and psychology? A fertile perspective on the problem is via the history of science and technology, paying particular attention to social groups and disciplinary identity to determine how those factors affected their communities’ cognitive territory. There were both common and discordant threads motivating the various technical groups that took on the problems of measuring light and color from the late nineteenth century onwards, and leading them towards the development of appropriate instruments for themselves. The transition from visual to photoelectric methods <i>could</i> be portrayed as a natural evolution, replacing the eye by an alternative roviding more sensitivity and convenience – indeed, this is the conventional positivist view propounded by technical histories. However, the adoption of new measurement technologies seldom is simple, and frequently has a significant cultural component. Beneath this slide towards automation lay a raft of implicit assumptions about objectivity, the nature of the observer, the role of instruments, and the trade-offs between standardization and descriptive power. While espousing rational arguments for a physical detector of color, its proponents weighted their views with tacit considerations. The reassignment of trust from the eye to automated instruments was influenced as much by the historical context as by intellectual factors. I will argue that several distinct aspects were involved, which include the reductive view of color provided by the trichromatic theory; the impetus provided by its association with photometry; the expanding mood for a quantitative and objective approach to scientific observation; and, the pressures for commercial standardization. As suggested by these factors, there was another shift of authority at play: from one technical specialism to another. The regularization of color involved appropriation of the subject by a particular set of social interests: communities of physicists and engineers espousing a ‘physicalist’ interpretation, rather than psychologists and physiologists for whom color was conceived as a more complex phenomenon. Moreover, the sources for automated color measurement, and instrumentation for measuring color, were primarily from the industrial sphere rather than from academic science. To understand these shifts, then, this chapter explores differing views of the importance of observers, machines and automation

The multi-fractal structure of contrast changes in natural images: from sharp edges to textures

We present a formalism that leads very naturally to a hierarchical description of the different contrast structures in images, providing precise definitions of sharp edges and other texture components. Within this formalism, we achieve a decomposition of pixels of the image in sets, the fractal components of the image, such that each set only contains points characterized by a fixed stregth of the singularity of the contrast gradient in its neighborhood. A crucial role in this description of images is played by the behavior of contrast differences under changes in scale. Contrary to naive scaling ideas where the image is thought to have uniform transformation properties \cite{Fie87}, each of these fractal components has its own transformation law and scaling exponents. A conjecture on their biological relevance is also given.Comment: 41 pages, 8 figures, LaTe

Quasars and Galactic Nuclei,a Half-Century Agitated Story

I recall how the discovery of quasars occurred more than forty years ago, and the strong debates marking out their story. It led to the discovery of Massive Black Holes, which are now known to be present in almost all galaxies, and it opened on a coherent physical model and on a new vision of galaxy evolution.Comment: 14 pages, 4 figures, talk given at the Albert Einstein Century International Conference, held in Paris, France, July 18-22, 2005, submitted to publication in AIP, Eds J.-M. Alimi and A. Fuzfa, replaced to add few references and to correct a mistak