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M. Armano et al., The Laser Interferometer Space Antenna Pathfinder (LPF) main observable, labeled Δg, is the differential force per unit mass acting on the two test masses under free fall conditions after the contribution of all non-gravitational forces has been compensated. At low frequencies, the differential force is compensated by an applied electrostatic actuation force, which then must be subtracted from the measured acceleration to obtain Δg. Any inaccuracy in the actuation force contaminates the residual acceleration. This study investigates the accuracy of the electrostatic actuation system and its impact on the LPF main observable. It is shown that the inaccuracy is mainly caused by the rounding errors in the waveform processing and also by the random error caused by the analog to digital converter random noise in the control loop. Both errors are one order of magnitude smaller than the resolution of the commanded voltages. We developed a simulator based on the LPF design to compute the close-to-reality actuation voltages and, consequently, the resulting actuation forces. The simulator is applied during post-processing the LPF data., This work was supported by ETH Research Grant No. ETH-05 16-2, and it has been made possible by the LISA Pathfinder mission, which is part of the space-science program of the European Space Agency. The French contribution has been supported by the CNES (Accord Specific de Projet Grant No. CNES 1316634/CNRS 103747), the CNRS, the Observatoire de Paris, and University Paris-Diderot. E. Plagnol and H. Inchauspé would also like to acknowledge the financial support of the UnivEarthS Labex program at Sorbonne Paris Cité (Grant Nos. ANR-10-LABX-0023 and ANR-11-IDEX-0005-02). The Albert-Einstein-Institut acknowledges the support of the German Space Agency, DLR. The work is supported by the Federal Ministry for Economic Affairs and Energy based on a resolution of the German Bundestag (Grant Nos. FKZ 50OQ0501 and FKZ 50OQ1601). The Italian contribution has been supported by the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare. The Spanish contribution has been supported by Contract Nos. AYA2010-15709 (MICINN), ESP2013-47637-P, ESP2015-67234-P, and ESP2017-90084-P (MINECO). Support from AGAUR (Generalitat de Catalunya) contract 2017-SGR-1469 is also acknowledged. M. Nofrarias acknowledges support from Fundacion General CSIC (Programa ComFuturo). F. Rivas acknowledges an FPI contract from MINECO. The Swiss contribution acknowledges the support of the Swiss Space Office (SSO) via the PRODEX Programme of the ESA. L. Ferraioli is supported by the Swiss National Science Foundation. The UK groups wish to acknowledge support from the United Kingdom Space Agency (UKSA), the University of Glasgow, the University of Birmingham, Imperial College, and the Scottish Universities Physics Alliance (SUPA). J. I. Thorpe and J. Slutsky acknowledge the support of the U.S. National Aeronautics and Space Administration (NASA). N. Korsakova would like to thank the support from the CNES Fellowship. The LISA Pathfinder collaboration would like to acknowledge Professor Pierre Binetruy (deceased 30 March 2017) and Professor José Alberto Lobo (deceased 30 September 2012) for their contribution to the LISA Pathfinder science.

LISA Pathfinder (LPF) has been a space-based mission designed to test new technologies that will be required for a gravitational wave observatory in space. Magnetically driven forces play a key role in the instrument sensitivity in the low-frequency regime (mHz and below), the measurement band of interest for a space-based observatory. The magnetic field can couple to the magnetic susceptibility and remanent magnetic moment from the test masses and disturb them from their geodesic movement. LISA Pathfinder carried on-board a dedicated magnetic measurement subsystem with noise levels of 10 $ \rm nT \ Hz^{-1/2}$ from 1 Hz down to 1 mHz. In this paper we report on the magnetic measurements throughout LISA Pathfinder operations. We characterise the magnetic environment within the spacecraft, study the time evolution of the magnetic field and its stability down to 20 $\mu$Hz, where we measure values around 200 $ \rm nT \ Hz^{-1/2}$ and identify two different frequency regimes, one related to the interplanetary magnetic field and the other to the magnetic field originating inside the spacecraft. Finally, we characterise the non-stationary component of the fluctuations of the magnetic field below the mHz and relate them to the dynamics of the solar wind., Comment: 16 pages, 17 figures. MNRAS LaTeX style file version 3.0

Cultural-historical activity theory (CHAT) approaches to intervention aim for transformative agency, that is, collective actions that expand and bring about new possibilities for activity. In this article, we draw on CHAT as a resource for organizing design research that promotes teachers’ agency in designing new science curriculum materials. We describe how CHAT informed our efforts to structure a collaborative design space in which teachers and other participants sought to develop new curriculum materials intended to help realize a new vision for science education. Specifically, we describe the tools and routines we deployed to support the design process, and we analyze the ways in which teachers took up elements of our design process as well as how they adapted, resisted, and suggested alternative tools and strategies to help develop new curriculum materials. In so doing, we illustrate ways in which CHAT can serve as a guide both for organizing collaborative design processes and for analyzing their eff...

This paper examines the impacts of technology (e.g., Chromebooks, Google Drive) on teacher learning and student activity in the development and implementation of a deeply digital high school biology unit. Using design-based implementation research, teachers co-designed with researchers and curriculum specialists a student-centered unit aligned to the Next Generation Science Standards (NGSS) that utilizes classroom technology. Qualitative and quantitative data were collected to understand the barriers that inhibit the implementation of a digital curriculum as well as the extent that teachers engage in the design process and begin to make shifts in their practice. We found that through the co-design process teachers began to shift their knowledge of NGSS, technology implementation, and adapted to tensions and barriers inherent in the process.

Several strands of Learning Sciences research have conceptualized teaching as a design activity and examined resulting instructional entailments. For example, research has shown that participating in teaching as a design process can help teachers learn new content and skills, enhance their students’ learning, while also serve to support and sustain curricular innovations. With the emergence of networked technologies to support learning, new questions about how to frame teaching as a design activity are again at the forefront. Within this realm, one important innovation is open educational resources (Oer) –freely available and customizable online teaching and learning resources. With their rapidly growing availability, teachers are increasingly turning to Oer to design instructional experiences for their students. This chapter explores the role technology can play in supporting teachers as they use, adapt, customize, and share Oer to design instructional experiences for their students. It first describes conceptual frameworks informing the teaching as design research agenda: pedagogical design capacity, peer production, and use diffusion. Then, two technology models are presented that support these processes and we describe their implementation in two software tools, the Instructional Architect and the Curriculum Customization Service. While the two tools occupy different parts of the design space, they aim to support teachers through leveraging peer production processes around teachers’ varying levels of pedagogical design capacity. The chapter summarizes findings from studies of teacher use of these two tools and concludes by discussing implications of this perspective for research and practice.

This paper describes a methodology to analyze, in the frequency domain, the steady-state control performances of the LISA Pathfinder mission. In particular, it provides a technical framework to give a comprehensive understanding of the spectra of all the degrees of freedom by breaking them down into their various physical origins, hence bringing out the major contributions of the control residuals. A reconstruction of the measured in-loop output, extracted from a model of the closed-loop system, is shown as an instance to illustrate the potential of such a model breakdown of the data.

LISA Pathfinder, the European Space Agency's technology demonstrator mission for future spaceborne gravitational wave observatories, was launched on 3 December 2015, from the European space port of Kourou, French Guiana. After a short duration transfer to the final science orbit, the mission has been gathering science data since. This data has allowed the science community to validate the critical technologies and measurement principle for low frequency gravitational wave detection and thereby confirming the readiness to start the next generation gravitational wave observatories, such as LISA. This paper will briefly describe the mission, followed by a description of the science operations highlighting the performance achieved. Details of the various experiments performed during the nominal science operations phase can be found in accompanying papers in this volume.

We report on the development of the LISA Technology Package (LTP) experiment that will fly onboard the LISA Pathfinder mission of the European Space Agency in 2008. We first summarize the science rationale of the experiment aimed at showing the operational feasibility of the so-called transverse–traceless coordinate frame within the accuracy needed for LISA. We then show briefly the basic features of the instrument and we finally discuss its projected sensitivity and the extrapolation of its results to LISA.

Thermal Diagnostics experiments to be carried out on board LISA Pathfinder (LPF) will yield a detailed characterisation of how temperature fluctuations affect the LTP (LISA Technology Package) instrument performance, a crucial information for future space based gravitational wave detectors as the proposed eLISA. Amongst them, the study of temperature gradient fluctuations around the test masses of the Inertial Sensors will provide as well information regarding the contribution of the Brownian noise, which is expected to limit the LTP sensitivity at frequencies close to 1mHz during some LTP experiments. In this paper we report on how these kind of Thermal Diagnostics experiments were simulated in the last LPF Simulation Campaign (November, 2013) involving all the LPF Data Analysis team and using an end-to-end simulator of the whole spacecraft. Such simulation campaign was conducted under the framework of the preparation for LPF operations. Spanish Ministry of Science and Innovation (MICINN)/AYA2010-15709

Reuse of educational materials is integral to many educator tasks, from designing a course to preparing for a lab or class. We are studying the reuse of educational materials in the context of the Digital Library for Earth System Education (DLESE). DLESE is a community-owned and governed facility offering high-quality teaching and learning resources for Earth system education. Our studies build on a cognitive framework that posits that people engage in three cyclical processes—location, comprehension, and modification—when reusing resources from large digital repositories. Our formative evaluations and cataloging experiences in DLESE suggest that the ‘findability’ and reusability of community-created digital educational resources is highly dependent on the presentational and structural design of the resources themselves. Educational resource designers often do not develop components with reuse in mind, making it more difficult or impossible for other educators to find and use their material. We share the ...

We present a new technical simulator for the eLISA mission, based on state space modeling techniques and developed in MATLAB. This simulator computes the coordinate and velocity over time of each body involved in the constellation, i.e. the spacecraft and its test masses, taking into account the different disturbances and actuations. This allows studying the contribution of instrumental noises and system imperfections on the residual acceleration applied on the TMs, the latter reflecting the performance of the achieved free-fall along the sensitive axis. A preliminary version of the results is presented. Sorbonne Paris Cite/UnivEarthS Labex French Space Agency (CNES)

How can new media positively transform scholarly practices? One possible way is for scholarly archives such as e-journals and digital libraries to better support the needs and practices of their us...

The parallel session C5 on Space-Based Detectors gave a broad overview over the planned space missions related to gravitational wave detection. Overviews of the revolutionary science to be expected from LISA was given by Alberto Sesana and Sasha Buchman. The launch of LISA Pathfinder (LPF) is planned for 2015. This mission and its payload “LISA Technology Package” will demonstrate key technologies for LISA. In this context, reference masses in free fall for LISA, and gravitational physics in general, was described by William Weber, laser interferometry at the pico-metre level and the optical bench of LPF was presented by Christian Killow and the performance of the LPF optical metrology system by Paul McNamara. While LPF will not yet be sensitive to gravitational waves, it may nevertheless be used to explore fundamental physics questions, which was discussed by Michele Armano. Some parts of the LISA technology that are not going to be demonstrated by LPF, but under intensive development at the moment, were presented by Oliver Jennrich and Oliver Gerberding. Looking into the future, Japan is studying the design of a mid-frequency detector called DECIGO, which was discussed by Tomotada Akutsu. Using atom interferometry for gravitational wave detection has also been recently proposed, and it was critically reviewed by Peter Bender. In the nearer future, the launch of GRACE Follow-On (for Earth gravity observation) is scheduled for 2017, and it will include a Laser Ranging Interferometer as technology demonstrator. This will be the first inter-spacecraft laser interferometer and has many aspects in common with the LISA long arm, as discussed by Andrew Sutton.

Design problem-solving requires designers to be creative and to express evaluative judgments. Designers propose successive partial solutions and evaluate these solutions with respect to various criteria and constraints. Evaluation plays a major role in design because each successive evaluation step guides the course of design activity. However, evaluation of design solutions is difficult for both experienced and inexperienced designers because: (1) in complex domains, no single person can know all the relevant criteria and constraints, and (2) design solutions must be evaluated from multiple, and sometimes conflicting, perspectives. Domain-oriented design environments have been proposed as computational tools supporting designers to construct and evaluate design solutions. Critiquing systems embedded in these environments support evaluation activities by analysing design solutions for compliance with criteria and constraints encoded in the systems' knowledge-base. To investigate the impact of such systems, we have designed, built, and evaluated a domain-oriented design environment for a specific area: phone-based interface design. Professional designers were observed using the design environment to solve a complex design task. Analyses of these design sessions enabled us to identify reactions common to all designers, as well as reactions depending on the designers' level of domain experience.

This study explored the impact of prior domain knowledge on students’ strategies and use of digital resources during a Web-based learning task. Domain knowledge was measured using pre- and posttests of factual knowledge and knowledge application. Students utilized an age- and topic-relevant collection of 796 Web resources drawn from an existing educational digital library to revise essays that they had written prior to the online learning task. Following essay revision, participants self-reported their strategies for improving their essays. Screen-capture software was used to record all student interactions with Web-based resources and all modifications to their essays. Analyses examined the relationship between different levels of students’ prior knowledge and online learning behaviors, self-reported strategies, and learning outcomes. Findings demonstrated that higher levels of factual prior knowledge were associated with deeper learning and stronger use of digital resources, but that higher levels of deep prior knowledge were associated with less frequent use of online content and fewer deep revisions. These results suggest that factual knowledge can serve as a useful knowledge base during self-directed, online learning tasks, but deeper prior knowledge may lead novice learners to adopt suboptimal processes and behaviors.

Many teachers yearn to break through the confines of traditional textbook-centered teaching to present activities that encourage students to explore and construct their own knowledge. But this requires developing innovative materials and curriculum tailored to local students. Teachers have neither the time nor the information to do much of this from scratch. The Internet provides a medium for sharing innovative educational resources globally. School districts and teacher organizations have already begun to post curriculum ideas on Internet servers. However, just storing unrelated educational materials on the Internet does not by itself solve the problem. It is too hard to find the right resources to meet specific needs. Teachers need productivity software for locating sites of materials across the network, searching the individual curriculum sources, adapting retrieved materials to their classrooms, organizing these resources in coherent lesson plans, and sharing their experiences across the Internet. We have designed and prototyped a Teacher's Curriculum Assistant (TCA) that provides software support for teachers to make effective use of educational resources posted to the Internet. TCA maintains information for finding educational resources distributed on the Internet. It provides query and browsing mechanisms for exploring what is available. Tools are included for tailoring retrieved resources, creating supplementary materials, and designing innovative curriculum. TCA encourages teachers to annotate and upload successfully used curriculum to Internet servers to share their ideas with other teachers. In this paper we motivate the need for such computer support and discuss what we have learned from designing TCA.

Recommender systems have become part of the standard toolkit of web personalization. These same tools and techniques are now making their way into educational and adaptive e-learning systems. In this chapter, we will discuss aspects of a prototype system, the Customized Learning Service for Concept Knowledge (CLICK), an application designed to provide digital library resources recommendations based on user’s concept knowledge demonstrated through automated evaluation and approximation of their knowledge state from essay writing. We present the underlying concepts behind recommender systems, review learner models as they are designed within the CLICK environment, and review the lessons learned. We will discuss aspects of how CLICK supports intentional learning as well as extensions to the existing technology to improve such support. Future challenges and directions for CLICK and related technologies are also discussed.

This chapter discusses an emerging theme in supporting effective multimedia learning: developing scalable, cognitively-grounded tools that customize learning interactions for individual students. We discuss the theoretical foundation for expected benefits of customization and current approaches in educational technology that leverage a learner’s prior knowledge. We then describe the development of a customized tool for science learning, called CliCk, that uses automatic techniques to create knowledge models that can be fed into cognitively-informed pedagogical tools. CliCk leverages existing multimedia resources in educational digital libraries for two purposes: (a) to generate rich representations of domain content relevant for learner modeling that are easily scaled to new domains and disciplines, and (b) to serve as a repository of instructional resources that support customized pedagogical interactions. The potential of the CliCk system is discussed, along with initial comparisons of knowledge models created by CliCk and human experts. Finally, the chapter discusses the remaining challenges and relevant future extensions for effective customization tools in educational technology.

The limited scope of digital libraries can be attributed to the brick and mortar vision of the library metaphor. In order to extend scope of digital libraries, in this chapter we examine the current supports and future possibilities afforded by digital libraries to support conventional consumers (i.e., information- users and information-curators), as well as emerging new types of consumers such as distributed computer applications. A functional analysis of conventional libraries is coupled with metaphor design methodology to explore new promising applications and usage scenarios for digital libraries.

This paper describes the design and evaluation of an extractive summarizer for educational science content called COGENT. COGENT extends MEAD based on strategies elicited from an empirical study with science domain and instructional design experts. COGENT identifies sentences containing pedagogically relevant concepts for a specific science domain. The algorithms pursue a hybrid approach integrating both domain independent bottom-up sentence scoring features and domain-aware top-down features. Evaluation results indicate that COGENT outperforms existing summarizers and generates summaries that closely resemble those generated by human experts. COGENT concept inventories appear to also support the computational identification of student misconceptions about earthquakes and plate tectonics.