Safe2Ditch Steer-To-Clear Development and Flight Testing

This paper describes a series of small unmanned aerial system (sUAS) flights performed at NASA Langley Research Center in April and May of 2019 to test a newly added Steer-to-Clear feature for the Safe2Ditch (S2D) prototype system. S2D is an autonomous crash management system for sUAS. Its function is to detect the onset of an emergency for an autonomous vehicle, and to enable that vehicle in distress to execute safe landings to avoid injuring people on the ground or damaging property. Flight tests were conducted at the City Environment Range for Testing Autonomous Integrated Navigation (CERTAIN) range at NASA Langley. Prior testing of S2D focused on rerouting to an alternate ditch site when an occupant was detected in the primary ditch site. For Steer-to-Clear testing, S2D was limited to a single ditch site option to force engagement of the Steer-to-Clear mode. The implementation of Steer-to-Clear for the flight prototype used a simple method to divide the target ditch site into four quadrants. An RC car was driven in circles in one quadrant to simulate an occupant in that ditch site. A simple implementation of Steer-to- Clear was programmed to land in the opposite quadrant to maximize distance to the occupants quadrant. A successful mission was tallied when this occurred. Out of nineteen flights, thirteen resulted in successful missions. Data logs from the flight vehicle and the RC car indicated that unsuccessful missions were due to geolocation error between the actual location of the RC car and the derived location of it by the Vision Assisted Landing component of S2D on the flight vehicle. Video data indicated that while the Vision Assisted Landing component reliably identified the location of the ditch site occupant in the image frame, the conversion of the occupants location to earth coordinates was sometimes adversely impacted by errors in sensor data needed to perform the transformation. Logged sensor data was analyzed to attempt to identify the primary error sources and their impact on the geolocation accuracy. Three trends were observed in the data evaluation phase. In one trend, errors in geolocation were relatively large at the flight vehicles cruise altitude, but reduced as the vehicle descended. This was the expected behavior and was attributed to sensor errors of the inertial measurement unit (IMU). The second trend showed distinct sinusoidal error for the entire descent that did not always reduce with altitude. The third trend showed high scatter in the data, which did not correlate well with altitude. Possible sources of observed error and compensation techniques are discussed

Integrative analysis of large-scale biological data sets

We present two novel web-applications for microarray and gene/protein set analysis, ArrayMining.net and TopoGSA. These bioinformatics tools use integrative analysis methods, including ensemble and consensus machine learning techniques, as well as modular combinations of different analysis types, to extract new biological insights from experimental transcriptomics and proteomics data. They enable researchers to combine related algorithms and datasets to increase the robustness and accuracy of statistical analyses and exploit synergies of different computational methods, ranging from statistical learning to optimization and topological network analysis

PathExpand: Extending biological pathways using molecular interaction networks

We present a methodology for extending pre-defined protein sets representing cellular pathways and processes by mapping them onto a protein-protein interaction network, and extending them to include densely interconnected interaction partners. The added proteins display distinctive network topological features and molecular function annotations, and can be proposed as putative new components, and/or as regulators of the communication between the different cellular processes. Finally, these extended pathways and processes are used to analyze their enrichment in cancer mutated genes. Significant associations between mutated genes and certain processes are identified, enabling an analysis of the influence of previously non-annotated cancer mutated genes

vrmlgen: An R Package for 3D Data Visualization on the Web

The 3-dimensional representation and inspection of complex data is a frequently used strategy in many data analysis domains. Existing data mining software often lacks functionality that would enable users to explore 3D data interactively, especially if one wishes to make dynamic graphical representations directly viewable on the web. In this paper we present vrmlgen, a software package for the statistical programming language R to create 3D data visualizations in web formats like the Virtual Reality Markup Language (VRML) and LiveGraphics3D. vrmlgen can be used to generate 3D charts and bar plots, scatter plots with density estimation contour surfaces, and visualizations of height maps, 3D object models and parametric functions. For greater flexibility, the user can also access low-level plotting methods through a unified interface and freely group different function calls together to create new higher-level plotting methods. Additionally, we present a web tool allowing users to visualize 3D data online and test some of vrmlgen's features without the need to install any software on their computer.

In-situ examination of diffusion and precipitation processes during the evolution of chemical garden systems

“Chemical” or “silicate gardens” are a well known example for the spontaneous formation of a complex and structured system from ordinary educts. Simply by addition of soluble metal salt crystals to alkaline silica sols, dissolution of the metal salt and subsequent solidification initiate a self-organization process, which not only produces two separated compartments with drastically different chemical conditions by precipitation of a closed and tubular membrane but also produces a variety of stunning structures reminiscent of living forms such as trees or aquatic plants. Although a considerable number of scientific studies was dedicated to chemical gardens and related phenomena during the last more than 300 years, current literature is still lacking in central aspects of chemical garden growth. Especially due to the fact that most of the studies concentrated on ex-situ characterizations of these stunning architectures, only rare information is available to date on the evolution of dynamic processes occurring during their growth. The present thesis therefore mainly focuses on the time-resolved evaluation of crucial parameters in the course of chemical garden growth to contribute to the amplification of the knowledge on these long since discovered phenomena. Several strategies are developed in this work, aiming on the establishment of suitable in-situ examination techniques allowing for the direct observation of critical parameters in both generated compartments during chemical garden evolution. Implementation of a novel preparation procedure – involving the slow addition of sodium silicate solution to tablets of pressed metal salts (instead of small seed crystals) – yields in the formation of uniform and macroscopic tubular membranes with one end open to the atmosphere. This modification of the classical preparation procedure paves the way for directly accessing the heretofore caged interior compartment and therefore allows a continuous analysis by different techniques. X-ray absorption spectroscopy (XAS) and atomic emission spectroscopy (AES) techniques are applied to analyze the temporal evolution of ion species concentrations and their distribution in the outer and interior compartments of the generated silicate garden tubes. Together with continuous measurements of the pH in the interior and exterior compartments, these techniques are used for the detection of occurring diffusion processes across the precipitated tubular membrane and their temporal evolution. Presented results from these measurements show that chemical gardens are a complex system operating far from equilibrium due to a spontaneous separation of two solutions with drastic concentration differences by a porous membrane during the early stages of formation. It is demonstrated that the evolution of the system and its return to thermodynamic equilibrium are not at all completed once macroscopic growth of the well-known tubular structures is terminated. Instead, a series of diffusion and (coupled) precipitation processes occur over timeframes of up to days after preparation, gradually relieving the initially generated concentration gradients. The results of this work further illustrate that the walls of silica gardens allow bidirectional and non-specific ion transport, and thus fundamentally challenge the currently accepted model of a semi-permeable membrane. Observed concentration and pH gradients across the tube wall implicate the existence of appreciable potential differences between the two compartments, which were directly measured in this work. From results of long-term electrochemical potential measurements, it is deduced that the overall detected cell potential can be explained by a superposition of diffusion, membrane and pH induced potentials prevailing across the silicate garden walls. Different in-situ and ex-situ XRD techniques are used to identify the existence of crystalline material in the precipitated tube walls. Recorded data from independently obtained XRD analyses, together with results from AES and XAS measurements, are used to establish a model that describes the kinetics of precipitation and crystallization processes during chemical garden growth as those of an irreversible consecutive reaction. The kinetic model of silicate garden growth is found to be universally applicable and might therefore probably be transferable to other systems, in which a combination of dissolution, precipitation and crystallization processes play an important role, e.g. in the progress of Portland cement hydration. Ex-situ analyses of isolated membrane tubes on their structural and chemical composition, using scanning electron microscopy (SEM) in combination with energy dispersive X-ray spectroscopy (EDX), reveal a partial layering of the precipitated membrane tubes, exhibiting a silica-rich exterior and an interior surface mainly consisting of pure metal hydroxide. Furthermore, different kinds of stunning sub-structurings of the exterior and interior surfaces of the tubular precipitates are observed, ranging from periodical waviness on the exterior silica skin via interwoven fiber-networks up to clusters of metal oxide hydroxide rosettes or isolated crystallites. Therefore, this structural diversity directly mirrors the influence of the preparation technique as well as of precipitation and crystallization processes, occuring during the growth of chemical gardens, on their resulting structure

Improved Throughput with Cooperating Futuristic Airspace Management Components

An experiment was conducted to integrate airspace management tools that would typically be confined to either the en route or the terminal airspace to explore the potential benefits of their communication to improve arrival capacity. A NAS-wide simulation was configured with a new concept component that used the information to reconfigure the terminal airspace to the capacity benefit of the airport. Reconfiguration included a dynamically expanding and contracting TRACON area and a varying number of active arrival runways, both automatically selected to accommodate predicted volume of traffic. ATL and DFW were selected for the study. Results showed significant throughput increase for scenarios that are considered to be over-capacity for current day airport configurations. During periods of sustained demand for ATL 2018, throughput increased by 26 operations per hour (30%) and average delay was reduced from 18 minutes to 8 minutes per flight when using the dynamic TRACON. Similar results were obtained for DFW with 2018 traffic levels and for ATL with 2006 traffic levels, but with lower benefits due to lower demand

Confront and Cluster—How Different Groups of Primary School Children Respond to Instruction towards Conceptual Change at an Out-of-School Learning Setting

We sampled the alternative conceptions of 257 third grade students (8-11 years old) using an open questionnaire. The answers were categorized into three topics and used to construct a multiple choice instrument. Following the pretest our instruction phase contained the confrontation with the students’ own alternative conceptions about humans’ and cats’ vision at a wildlife-park. Immediately after instruction, the multiple choice instrument was presented as a post test and several weeks later as a retention test. Due to the heterogeneity within our student sample we defined and found five different groups. Our data shows that the instruction of primary school children using confrontation according to the conceptual change theory does not lead to a change of conceptions or to synthetic models, furthermore we found no detectable conceptual growth. Finally, students with the accepted scientific conception as well as students with other concepts seemed to be confused by this instruction

Improvement to Airport Throughput Using Intelligent Arrival Scheduling and an Expanded Planning Horizon

The first phase of this study investigated the amount of time a flight can be delayed or expedited within the Terminal Airspace using only speed changes. The Arrival Capacity Calculator analysis tool was used to predict the time adjustment envelope for standard descent arrivals and then for CDA arrivals. Results ranged from 0.77 to 5.38 minutes. STAR routes were configured for the ACES simulation, and a validation of the ACC results was conducted comparing the maximum predicted time adjustments to those seen in ACES. The final phase investigated full runway-to-runway trajectories using ACES. The radial distance used by the arrival scheduler was incrementally increased from 50 to 150 nautical miles (nmi). The increased Planning Horizon radii allowed the arrival scheduler to arrange, path stretch, and speed-adjust flights to more fully load the arrival stream. The average throughput for the high volume portion of the day increased from 30 aircraft per runway for the 50 nmi radius to 40 aircraft per runway for the 150 nmi radius for a traffic set representative of high volume 2018. The recommended radius for the arrival scheduler s Planning Horizon was found to be 130 nmi, which allowed more than 95% loading of the arrival stream

Material power and normative conflict in global and local agrifood governance: the lessons of 'golden rice' in India

"Sustainability aspects of the agrifood system play a pivotal role in today’s global governance at all levels of decision-making. Questions of food security and food safety, biodiversity or the fate of local practices and values reflect some of the sources of potential conflict between states, as well as between business, state, and civil society actors. This special section aims to investigate the interaction of global and local forces in shaping the sustainability of the agrifood system. The section chooses India as the setting in which to investigate the interaction between global and local forces due to the crucial role the food demand and supply of this rising power plays in today’s agrifood system. This article provides the special sections’ analytical framework, which uses the interplay of material and ideational dimensions of power as a focal lens. In addition, the article applies this framework to an empirical study of the political conflict around GMO foods in India, specifically the case of ‘Golden Rice’." [author's abstract