Between X and Y: how process tracing contributes to opening the black box of causality

This article maps the methodological debate on process tracing and discusses the diverse variants of process tracing in order to highlight the commonalities beyond diversity and disagreements. Today most authors agree that process tracing is aimed at unpacking causal and temporal mechanisms. The article distinguishes two main types of use for process tracing. Some are more inductive, aimed at theory building (i.e. at uncovering and specifying causal mechanisms) while others are more deductive, aimed at theory testing (and refining). The paper summarizes the main added value and drawbacks of process tracing. It ends by providing ten guidelines for when and how to apply process tracing

Massively Parallel Ray Tracing Algorithm Using GPU

Ray tracing is a technique for generating an image by tracing the path of light through pixels in an image plane and simulating the effects of high-quality global illumination at a heavy computational cost. Because of the high computation complexity, it can't reach the requirement of real-time rendering. The emergence of many-core architectures, makes it possible to reduce significantly the running time of ray tracing algorithm by employing the powerful ability of floating point computation. In this paper, a new GPU implementation and optimization of the ray tracing to accelerate the rendering process is presented

Linking legal scenarios to empirical data: process- tracing as a methodology in law

Different legal rules can lead to the same observable outcome, making it difficult to identify the most influential rule. This article addresses this gap by focusing on how competing explanatory theories derived from a doctrinal analysis can be assessed using a methodology called process-tracing. One of process-tracing’s main uses is to link explanatory theories to empirical evidence, permitting an assessment of causal mechanisms’ practical impact in comparison to each other. This article demonstrates the potential and practical implementation of process-tracing in the context of empirical legal research. In addition to the core characteristics of process-tracing, the paper clarifies when process-tracing can add to a doctrinal analysis and the requirements which have to be met. Furthermore, the process of linking doctrinal work with empirical evidence relying on process-tracing is shown, using the example of copyright ownership in the broadcasting sector. As a result, this paper demonstrates the added value of a process-tracing analysis carried out in addition to doctrinal work, in particular the insights into industry practice it generates

Decision Support Systems Process Tracing Using Hypermedia

Two main alternative approaches to analyzing decision processes--implicit input/output inference models and explicit tracing of observable decision process manifestations-are reviewed with emphasis on explicit tracing methods. An emerging technology, hypermedia, is then examined as to how it may facilitate the process tracing method of decision making analysis. Examples are presented of mappings between hypermedia computer/user interface functions (such as mouse movements and mouse clicks) and underlying decision process functions. Issues of data quality, breadth of application, and implementation cost are discussed. Hypermedia process tracing is compared with other process tracing methods, including monitoring of eye movements, verbal protocols, and non hypermedia computerized logging. Advantages and disadvantages of the hypermedia approach are identified. Further directions for the application of hypermedia process tracing include areas related to information retrieval, use of models, study of user interfaces, and the potential for using the techniques to identify and compare cognitive processes of decision makers

Reproducibility and speed of landmarking process in cephalometric analysis using two input devices: mouse-driven cursor versus pen

To define if the new portable appliances, like smartphone, iPad, small laptop and tablet can be used in cephalometric tracing without dropping out the validity of any measurement. METHODS:We investigated and compared the reproducibility and the speed of landmarks identification process on lateral X-rays in two input devices: a mouse-driven cursor and a pen used as input means in mobile devices. One expert located 22 landmarks on 15 lateral X-rays in a repeated measure design two times, at time T1 and T2, after at least one month. The Intraclass Correlation coefficient was used to evaluate the reproducibility for each landmark tracing and the agreement between the value derived from both input devices. Also, the mean errors in measurements, the standard deviation and the Friedman Test significans (P < 0.05) between both input were statistically evaluated. RESULTS:All landmarks had a high agreement and the Friedman Test indicated statistically significant differences (P<0.05) for the identification of Na, Po, Pt, PNS, Ba, Pg, Gn, UIE, UIA, APOcc and PPOcc landmarks. CONCLUSIONS:Even if the mouse input give higher agreement for landmark tracing the differences are really minimal and they can be ignored in private practice. We suggest the adequacy of pen input in clinical setting

Spectral properties of reduced fermionic density operators and parity superselection rule

We consider pure fermionic states with a varying number of quasiparticles and analyze two types of reduced density operators: one is obtained via tracing out modes, the other is obtained via tracing out particles. We demonstrate that spectra of mode-reduced states are not identical in general and fully characterize pure states with equispectral mode-reduced states. Such states are related via local unitary operations with states satisfying the parity superselection rule. Thus, valid purifications for fermionic density operators are found. To get particle-reduced operators for a general system, we introduce the operation $\Phi(\varrho) = \sum_i a_i \varrho a_i^{\dag}$. We conjecture that spectra of $\Phi^p(\varrho)$ and conventional $p$-particle reduced density matrix $\varrho_p$ coincide. Nontrivial generalized Pauli constraints are derived for states satisfying the parity superselection rule.Comment: 8 pages, a new section on particle-reduced density operators and generalized Pauli constraints, published version, Quantum Inf. Process. (2017) 16:

The Westerbork HALOGAS Survey: Status and Early Results

We present early results from the ongoing Hydrogen Accretion in LOcal GAlaxieS (HALOGAS) Survey, which is being performed with the Westerbork Synthesis Radio Telescope (WSRT). The HALOGAS Survey aims to detect and characterize the cold gas accretion process in nearby spirals, through sensitive observations of neutral hydrogen (HI) 21-cm line emission. In this contribution, we present an overview of ongoing analyses of several HALOGAS targets.Comment: To appear in proceedings of IAU Symposium 277, "Tracing the Ancestry of Galaxies on the Land of our Ancestors", eds. C. Carignan, K.C. Freeman, and F. Combe