Performance of Particle Flow Calorimetry at CLIC

The particle flow approach to calorimetry can provide unprecedented jet energy resolution at a future high energy collider, such as the International Linear Collider (ILC). However, the use of particle flow calorimetry at the proposed multi-TeV Compact Linear Collider (CLIC) poses a number of significant new challenges. At higher jet energies, detector occupancies increase, and it becomes increasingly difficult to resolve energy deposits from individual particles. The experimental conditions at CLIC are also significantly more challenging than those at previous electron-positron colliders, with increased levels of beam-induced backgrounds combined with a bunch spacing of only 0.5 ns. This paper describes the modifications made to the PandoraPFA particle flow algorithm to improve the jet energy reconstruction for jet energies above 250 GeV. It then introduces a combination of timing and p_T cuts that can be applied to reconstructed particles in order to significantly reduce the background. A systematic study is performed to understand the dependence of the jet energy resolution on the jet energy and angle, and the physics performance is assessed via a study of the energy and mass resolution of W and Z particles in the presence of background at CLIC. Finally, the missing transverse momentum resolution is presented, and the fake missing momentum is quantified. The results presented in this paper demonstrate that high granularity particle flow calorimetry leads to a robust and high resolution reconstruction of jet energies and di-jet masses at CLIC.Comment: 14 pages, 11 figure

Remote sensing impact on corridor selection and placement

Computer-aided corridor selection techniques, utilizing digitized data bases of socio-economic, census, and cadastral data, and developed for highway corridor routing are considered. Land resource data generated from various remote sensing data sources were successfully merged with the ancillary data files of a corridor selection model and prototype highway corridors were designed using the combined data set. Remote sensing derived information considered useful for highway corridor location, special considerations in geometric correction of remote sensing data to facilitate merging it with ancillary data files, and special interface requirements are briefly discussed

Knowledge of Objective 'Oughts': Monotonicity and the New Miners Puzzle

In the classic Miners case, an agent subjectively ought to do what they know is objectively wrong. This case shows that the subjective and objective ‘oughts’ are somewhat independent. But there remains a powerful intuition that the guidance of objective ‘oughts’ is more authoritative—so long as we know what they tell us. We argue that this intuition must be given up in light of a monotonicity principle, which undercuts the rationale for saying that objective ‘oughts’ are an authoritative guide for agents and advisors

Laser Doppler velocimeter system simulation for sensing aircraft wake vortices. Part 2: Processing and analysis of LDV data (for runs 1023 and 2023)

A data analysis program constructed to assess LDV system performance, to validate the simulation model, and to test various vortex location algorithms is presented. Real or simulated Doppler spectra versus range and elevation is used and the spatial distributions of various spectral moments or other spectral characteristics are calculated and displayed. Each of the real or simulated scans can be processed by one of three different procedures: simple frequency or wavenumber filtering, matched filtering, and deconvolution filtering. The final output is displayed as contour plots in an x-y coordinate system, as well as in the form of vortex tracks deduced from the maxima of the processed data. A detailed analysis of run number 1023 and run number 2023 is presented to demonstrate the data analysis procedure. Vortex tracks and system range resolutions are compared with theoretical predictions

A feasibility study for the detection of upper atmospheric winds using a ground based laser Doppler velocimeter

A possible measurement program designed to obtain the information requisite to determining the feasibility of airborne and/or satellite-borne LDV (Laser Doppler Velocimeter) systems is discussed. Measurements made from the ground are favored over an airborne measurement as far as for the purpose of determining feasibility is concerned. The expected signal strengths for scattering at various altitude and elevation angles are examined; it appears that both molecular absorption and ambient turbulence degrade the signal at low elevation angles and effectively constrain the ground based measurement of elevation angles exceeding a critical value. The nature of the wind shear and turbulence to be expected are treated from a linear hydrodynamic model - a mountain lee wave model. The spatial and temporal correlation distances establish requirements on the range resolution, the maximum detectable range and the allowable integration time

Party Booby Trap

Thomson & Craighead present their first fragrance Apocalypse (2016) in Party Booby Trap, the duo’s second solo show at Carroll / Fletcher. The scent will be showcased alongside a series of major new works inspired by sources ranging from nuclear waste to self-help literature and genetics. The late 20th century saw one of the most significant scientific advances to date, with the first mapping of a human genome (an individual’s complete DNA set) by the international Human Genome Project. It took thirteen years and twenty universities to reference over three billion base pairs of nucleotides (DNA molecules) that compose one single genome. This process has inspired Thomson & Craighead’s Stutterer (2014), a video installation the artists describe as a “poetry machine.” There are four types of DNA: adenine, cytosine, guanine, and thymine, commonly referred to as A, C, G, and T. The artists seized the creative opportunity afforded by the combination of a sequence of letters and a crucial tranche of recent history. The time it took to complete the Human Genome Project spanned the liberation of Nelson Mandela in 1990 and the fall of Baghdad to the allied military coalition in 2003. Supported by the Wellcome Trust, Stutterer (2014) pairs each letter of the first human genome with a word beginning with the same letter, spoken in television footage from the period. The result is a televisual portrait of an era which encompassed not only the First and the Second Gulf Wars, but also the collapse of the Soviet Union, the deaths of Yitzhak Rabin and Princess Diana, the first cloned sheep Dolly, the launch of Viagra and the shootings at Columbine High School. In October 2002, then-President George W. Bush declared that Iraq was in possession of chemical and biological weapons which “threatened America and the world” – an allegation which is now widely acknowledged as one of the main triggers for the Second Gulf War (2003-11). “Confronting the threat posed by Iraq,” he said, “is crucial to winning the War on Terror.” Thomson & Craighead’s print the war on terror (2016) plays with the phrase in a series of Oulipo-esque anagrams: “the rot narrower”, “tarot hewn error”, “rare tower thorn.” Made with a type-writer on a white sheet of paper like a piece of experimental poetry, these hint at the absurdity of the chain of events that led to the death of hundreds of thousands of civilians in less than a decade. Multi-coloured balloons bearing the names of military operations from “Desert Storm” to “Urgent Fury” crowd the floor. These innocuous presences – absent-mindedly kicked about by visitors as they progress through the exhibition – function as gentle reminders of the pervasive nature of warfare. On a TV screen, some women dutifully pop the balloons after a corporate party, as if trying to contain a reality that could overwhelm them. Created in collaboration with perfumer Euan McCall, the fragrance Apocalypse combines the scents of olfactory elements described in The Book of Revelation, including burnt flesh, incense and blood. Presented in a velvet-lined box, it turns a central tenet of the Western imaginary, and a canonical representation of End Times, into a luxury, limited edition item. At once highly desirable and sickening, the piece is the product of a time in which both consumerism and politics feed on fear, mysticism and fallacies of all stripes. With the series of posters Common Era (2016), Thomson & Craighead gather a collection of predictions for the end of the world: from Nostradamus – who famously declared that all would be over in 1999 – to Canadian philosopher John A. Leslie, who more optimistically estimated it would be by the year 11120. The soft palette and hand-made feel of these text pieces stands in stark contrast with their sensationalist content. They almost recall the mindfulness colouring books that topped the best-selling charts in 2015. While broadcasting collective anxiety about the destruction of humanity and “the world as we know it,” they bring the viewers towards something much more intimate, to do with personal angst and the quest for happiness. Help Yourself and A Temporary Index (both 2016), articulate this push-and-pull between concern for the common good and individual fulfilment. The first piece combines found digital video material, originally designed to prevent the on-screen accumulation of dead pixels, and a series of self-improvement tapes. Viewers can navigate them – going from, say, “how to attract money” to “weight loss” or, “sales motivation” by plugging headphones into different sockets. Meanwhile, on a large free-standing screen, A Temporary Index gives, in seconds, the estimated time it will take for sites storing entombed radioactive waste to be safe again for humans. These range from a few decades to a million years. The numbers are presented vertically and doubled up, standing like totems. Thus abstracted, they are almost as incomprehensible as the durations they represent. Party Booby Trap (the title is a palindrome, like most of Thomson & Craighead’s exhibition titles) splices these temporalities: the deep time of nuclear decay and apocalyptic visions is put side by side with the dizzying brevity of the human lifespan (or a political career). The exhibition harks back to a seminal religious text, and links it to belief systems of all kinds, arguably including democracy, science and art itself

Laser Doppler velocimeter system simulation for sensing aircraft wake vortices

A hydrodynamic model of aircraft vortex wakes in an irregular wind shear field near the ground is developed and used as a basis for modeling the characteristics of a laser Doppler detection and vortex location system. The trailing vortex sheet and the wind shear are represented by discrete free vortices distributed over a two-dimensional grid. The time dependent hydrodynamic equations are solved by direct numerical integration in the Boussinesq approximation. The ground boundary is simulated by images, and fast Fourier Transform techniques are used to evaluate the vorticity stream function. The atmospheric turbulence was simulated by constructing specific realizations at time equal to zero, assuming that Kolmogoroff's law applies, and that the dissipation rate is constant throughout the flow field. The response of a simulated laser Doppler velocimeter is analyzed by simulating the signal return from the flow field as sensed by a simulation of the optical/electronic system

Solvation forces in Ising films with long-range boundary fields: density-matrix renormalization-group study

Using the quasi-exact density-matrix renormalization-group method we calculate the solvation forces in two-dimensional Ising films of thickness L subject to identical algebraically decaying boundary fields with various decay exponents p. At the bulk critical point the solvation force acquires a universal contribution which is long-ranged in L due to the critical fluctuations, a phenomenon known as the critical Casimir effect. For p = 2, 3 and 50, we study the scaling behaviour of the solvation force along the pseudo-phase coexistence and along the critical and sub-critical isotherms.Comment: 9 pages, 6 figures, accepted to Molecular Physic

Calculation of Elastic Green's Functions for Lattices with Cavities

In this Brief Report, we present an algorithm for calculating the elastic Lattice Greens Function of a regular lattice, in which defects are created by removing lattice points. The method is computationally efficient, since the required matrix operations are on matrices that scale with the size of the defect subspace, and not with the size of the full lattice. This method allows the treatment of force fields with multi-atom interactions.Comment: 3 pages. RevTeX, using epsfig.sty. One figur