243 research outputs found
Development of Metacognitive and Discursive Activities in Indonesian Maths Teaching
We report on a German-Indonesian design research project, which aims to significantly increase the mathematical skills of secondary school students. Since results of International comparative studies have shown that there exists a relationship between metacognition and learning success, a learning environment for the beginning with secondary school mathematics in class seven has been developed, in order to significantly enhance metacognitive and discursive activities of students and teachers. The effectiveness of the approach has been tested in a secondary school several times. In this paper the theoretical background for the design of the learning environment is described, some sample exercises are presented and student productions from the project lessons analysed
Developing Metacognitive and Discursive Activities in the Indonesian Mathematics Education
This article reports on the findings of a German-Indonesian feasibility study, which has been conducted to examine whether a more extensive pilot study could be successful. The objective of the pilot study is to enhance the mathematical skills of Indonesian students in the 7th class by increasing the number of students who can really understand the mathematical concepts and methods introduced in class. In order to achieve this, a learning environment for the introduction of integers was designed and implemented in class. During its implementation a teaching style has been practised which encourages metacognitive and discursive activities in the students. In this paper the theoretical background for the construction of a comparing test is set out, several exercises are presented as examples and on the basis of student solutions, taken from the test, the effects of the innovative teaching is demonstrated
Developing Metacognitive and Discursive Activities in the Indonesian Mathematics Education
This article reports on the findings of a German-Indonesian feasibility study, which has been conducted to examine whether a more extensive pilot study could be successful. The objective of the pilot study is to enhance the mathematical skills of Indonesian students in the 7th class by increasing the number of students who can really understand the mathematical concepts and methods introduced in class. In order to achieve this, a learning environment for the introduction of integers was designed and implemented in class. During its implementation a teaching style has been practised which encourages metacognitive and discursive activities in the students. In this paper the theoretical background for the construction of a comparing test is set out, several exercises are presented as examples and on the basis of student solutions, taken from the test, the effects of the innovative teaching is demonstrated
Can global precipitation datasets benefit the estimation of the area to be cropped in irrigated agriculture?
The area to be cropped in irrigation districts needs to be
planned according to the available water resources to avoid agricultural
production loss. However, the period of record of local hydro-meteorological
data may be short, leading to an incomplete understanding of climate
variability and consequent uncertainty in estimating surface water
availability for irrigation area planning. In this study we assess the
benefit of using global precipitation datasets to improve surface water
availability estimates. A reference area that can be irrigated is established
using a complete record of 30 years of observed river discharge data. Areas
are then determined using simulated river discharges from six local
hydrological models forced with in situ and global precipitation datasets
(CHIRPS and MSWEP), each calibrated independently with a sample of 5 years
extracted from the full 30-year record. The utility of establishing the
irrigated area based on simulated river discharge simulations is compared
against the reference area through a pooled relative utility value (PRUV).
Results show that for all river discharge simulations the benefit of choosing
the irrigated area based on the 30 years of simulated data is higher compared
to using only 5 years of observed discharge data, as the statistical spread
of PRUV using 30 years is smaller. Hence, it is more beneficial to calibrate
a hydrological model using 5 years of observed river discharge and then to
extend it with global precipitation data of 30 years as this weighs up
against the model uncertainty of the model calibration.</p
A strategy to characterize the LISA-Pathfinder cold gas thruster system
The cold gas micro-propulsion system that will be used during the LISA-Pathfinder mission will be one of the most important component used to ensure the "free-fall" of the enclosed test masses. In this paper we present a possible strategy to characterize the effective direction and amplitude gain of each of the 6 thrusters of this system
Free-flight experiments in LISA Pathfinder
The LISA Pathfinder mission will demonstrate the technology of drag-free test
masses for use as inertial references in future space-based gravitational wave
detectors. To accomplish this, the Pathfinder spacecraft will perform drag-free
flight about a test mass while measuring the acceleration of this primary test
mass relative to a second reference test mass. Because the reference test mass
is contained within the same spacecraft, it is necessary to apply forces on it
to maintain its position and attitude relative to the spacecraft. These forces
are a potential source of acceleration noise in the LISA Pathfinder system that
are not present in the full LISA configuration. While LISA Pathfinder has been
designed to meet it's primary mission requirements in the presence of this
noise, recent estimates suggest that the on-orbit performance may be limited by
this `suspension noise'. The drift-mode or free-flight experiments provide an
opportunity to mitigate this noise source and further characterize the
underlying disturbances that are of interest to the designers of LISA-like
instruments. This article provides a high-level overview of these experiments
and the methods under development to analyze the resulting data.Comment: 13 pages, 5 figures. Accepted to Journal Of Physics, Conference
Series. Presented at 10th International LISA Symposium, May 2014,
Gainesville, FL, US
The LISA pathfinder mission
ISA Pathfinder (LPF), the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology validation mission for future spaceborne gravitational wave detectors, such as the proposed eLISA mission. LISA Pathfinder, and its scientific payload - the LISA Technology Package - will test, in flight, the critical technologies required for low frequency gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. This is achieved through technology comprising inertial sensors, high precision laser metrology, drag-free control and an ultra-precise micro-Newton propulsion system. LISA Pathfinder is due to be launched in mid-2015, with first results on the performance of the system being available 6 months thereafter.
The paper introduces the LISA Pathfinder mission, followed by an explanation of the physical principles of measurement concept and associated hardware. We then provide a detailed discussion of the LISA Technology Package, including both the inertial sensor and interferometric readout. As we approach the launch of the LISA Pathfinder, the focus of the development is shifting towards the science operations and data analysis - this is described in the final section of the paper
In-flight thermal experiments for LISA pathfinder: simulating temperature noise at the inertial sensors
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 1 mHz 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
A noise simulator for eLISA: migrating LISA pathfinder knowledge to the eLISA mission
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
Disentangling the magnetic force noise contribution in LISA pathfinder
Magnetically-induced forces on the inertial masses on-board LISA Pathfinder are expected to be one of the dominant contributions to the mission noise budget, accounting for up to 40%. The origin of this disturbance is the coupling of the residual magnetization and susceptibility of the test masses with the environmental magnetic field. In order to fully understand this important part of the noise model, a set of coils and magnetometers are integrated as a part of the diagnostics subsystem. During operations a sequence of magnetic excitations will be applied to precisely determine the coupling of the magnetic environment to the test mass displacement using the on-board magnetometers. Since no direct measurement of the magnetic field in the test mass position will be available, an extrapolation of the magnetic measurements to the test mass position will be carried out as a part of the data analysis activities. In this paper we show the first results on the magnetic experiments during an end- to-end LISA Pathfinder simulation, and we describe the methods under development to map the magnetic field on-board
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