Observation of Free-Space Single-Atom Matterwave Interference

We observe matterwave interference of a single cesium atom in free fall. The interferometer is an absolute sensor of acceleration and we show that this technique is sensitive to forces at the level of $3.2\times10^{-27}$ N with a spatial resolution at the micron scale. We observe the build up of the interference pattern one atom at a time in an interferometer where the mean path separation extends far beyond the coherence length of the atom. Using the coherence length of the atom wavepacket as a metric, we directly probe the velocity distribution and measure the temperature of a single atom in free fall.Comment: 5 pages, 4 figure

Digital evidence, 'absence' of data and ambiguous patterns of reasoning

In this paper we discuss the use of digital data by the Swiss Federal Criminal Court in a recent case of attempted homicide. We use this case to examine drawbacks for the defense when the presentation of scientific evidence is partial, especially when the only perspective mentioned is that of the prosecution. We tackle this discussion at two distinct levels. First, we pursue an essentially non-technical presentation of the topic by drawing parallels between the court's summing up of the case and flawed patterns of reasoning commonly seen in other forensic disciplines, such as DNA and particle traces (e.g., gunshot residues). Then, we propose a formal analysis of the case, using elements of probability and graphical probability models, to justify our main claim that the partial presentation of digital evidence poses a risk to the administration of justice in that it keeps vital information from the defense. We will argue that such practice constitutes a violation of general principles of forensic interpretation as established by forensic science literature and current recommendations by forensic science interest groups (e.g., the European Network of Forensic Science Institutes). Finally, we posit that argument construction and analysis using formal methods can help replace digital evidence appropriately into context and thus support a sound evaluation of the evidence

Drawbacks in the scientification of forensic science

This letter to the Editor comments on the article On the limitations of probability in conceptualizing pattern matches in forensic science by P. T. Jayaprakash (Forensic Science Internationa

A Methodology for Invasive Programming on Virtualizable Embedded MPSoC Architectures

AbstractExploiting the huge logic resources in current embedded devices has led to a plethora of on-chip multi-processor architec- tures. However, besides instantiating more and more soft-core processors on a chip, developing applications suited for such architectures still remains a hard task. A further step in the evolution of embedded multi-processing might be the so called Invasive Programming. In this paradigm, an application may be switched from sequential to parallel execution at runtime. A task may then dynamically invade currently unused processor resources in a multi-processor system to resume in parallel execution mode. This hardens existing problems, however, because not only the development of suited software, but also the creation of multi-processor architectures supporting this paradigm is needed. Therefore, this work presents a concise methodology to enable Invasive Programming properties on an embedded Multi-Processor System-on-Chip (MPSoC). This is achieved by combining a designer-guided code parallelization approach with a virtualizable, generic, and scalable embedded MPSoC architecture. To resolve data dependencies during task invasion, a processor-independent task-based communication scheme for the MPSoC is proposed. Moreover, a tool framework dedicated to the generic creation of virtualizable MPSoC is provided. The approach is demonstrated by the generation of an MPSoC featuring eight processors executing an application which dynamically switches at runtime between sequential and parallel execution

Evaluation of forensic genetics findings given activity level propositions: A review.

The evaluation of results of forensic genetic analyses given activity level propositions is an emerging discipline in forensic genetics. Although it is a topic with a long history, it has never been considered to be such a critically important topic for the field, as today. With the increasing sensitivity of analysis techniques, and advances in data interpretation using probabilistic models ('probabilistic genotyping'), there is an increasing demand on forensic biologists to share specialised knowledge to help recipients of expert information address mode and timing of transfer and persistence of traces in court. Scientists thereby have a critical role in the assessment of their findings in the context of the case. This helps the judiciary with activity level inferences in a balanced, robust and transparent way, when based on (1) proper case assessment and interpretation respecting the hierarchy of propositions (supported by, for example, the use of Bayesian networks as graphical models), (2) use of appropriate data to inform probabilities, and (3) reporting guidelines by international bodies. This critical review of current literature shows that with certain prerequisites for training and quality assurance, there is a solid foundation for evidence interpretation when propositions of interest are at the 'activity level'

La naturaleza decisoria de las conclusiones de los expertos en ciencia forense (The decisionalization of individualization)

En la ciencia forense y ramas de la ciencia adyacentes, tanto investigadores del ámbito académico como quienes las practican continúan divergiendo en la percepción y comprensión del término “individualización”, es decir, la defensa de la tesis de que es posible reducir un conjunto de potenciales donantes de un vestigio forense a una única fuente. En concreto, se ha puesto de manifiesto que recientes cambios que entienden la práctica de la individualización como una decisión no son más que un mero cambio de etiqueta [1], dejando los cambios fundamentales en el orden del pensar y del entender aún pendientes. Es más, asociaciones profesionales y expertos huyen de adherirse a la noción de decisión tal y como la define la teoría formal de la decisión en la que la individualización puede contextualizarse, principalmente por las dificultades para tratar sobre las medidas de deseabilidad o no de las consecuencias de las decisiones (por ejemplo, utilizando las funciones de utilidad). Apoyándose en investigaciones existentes en esta área, este artículo presenta y discute sobre conceptos fundamentales de utilidades y costes, con particular referencia a su aplicación a la individualización forense. El artículo subraya que una adecuada comprensión de las herramientas de la decisión no solo reduce el número de asignaciones individuales que la aplicación de la teoría de la decisión requiere, sino que también muestra cómo esas asignaciones pueden relacionarse significativamente con las propiedades constituyentes del problema de la decisión en el mundo real al que se aplica la teoría. Se argumenta que la “decisionalización” de la individualización requiere esa percepción fundamental para iniciar cambios en las comprensiones subyacentes de esos campos, no meramente en el ámbito de sus etiquetas

Towards a Bayesian evaluation of features in questioned handwritten signatures

In this work, we propose the construction of a evaluative framework for supporting experts in questioned signature examinations. Through the use of Bayesian networks, we envision to quantify the probative value of well defined measurements performed on questioned signatures, in a way that is both formalised and part of a coherent approach to evaluation. At the current stage, our project is explorative, focusing on the broad range of aspects that relate to comparative signature examinations. The goal is to identify writing features which are both highly discriminant, and easy for forensic examiners to detect. We also seek for a balance between case-specific features and characteristics which can be measured in the vast majority of signatures. Care is also taken at preserving the interpretability at every step of the reasoning process. This paves the way for future work, which will aim at merging the different contributions to a single probabilistic measure of strength of evidence using Bayesian networks