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While there are many different frameworks seeking to identify what benefits young people might derive from participation in informal STEM (Science, Technology, Engineering and Mathematics) learning (ISL), this paper argues that the sector would benefit from an approach that foregrounds equity and social justice outcomes. We propose a new model for reflecting on equitable youth outcomes from ISL that identifies five key areas: (1) Grounded fun; (2) STEM capital; (3) STEM trajectories; (4) STEM identity work; and (5) Agency+. The model is applied to empirical data (interviews, observations and youth portfolios) collected over one year in four UK-based ISL settings with 33 young people (aged 11–14), largely from communities that are traditionally under-represented in STEM. Analysis considers the extent to which participating youth experienced equitable outcomes, or not, in relation to the five areas. The paper concludes with a discussion of implications for ISL and how the model might support ongoing efforts to reimagine ISL as vehicle for social justice. [ABSTRACT FROM AUTHOR]

The Ka-band dual one-way measurements from Inter-Satellite Link (ISL) devices equipped on the third-generation Beidou Navigation Satellite System (BDS3) follow a time division multiple access (TDMA) structure and can calculate inter-satellite and satellite-ground clock offsets. L-band two-way satellite time and frequency transfer (TWSTFT) is also applied for time synchronization between satellites and ground master. We focus on a full-ISL clock offset estimation and prediction algorithm that estimates all satellite clock parameters simultaneously utilizing ISL clock observations and also synchronizes the constellation to the system time in Beidou Time (BDT) using Ka-band satellite-ground clock observations. We discuss the applications of this algorithm by assessing the clock performance of all BDS3 satellites equipped with a passive hydrogen maser (PHM) or rubidium atomic clock. After investigating the proper prediction model for each satellite, we use the full-ISL algorithm for 24-h clock predictions. The constant hardware delays in the ISL measurements are calibrated by comparing the derived clock parameters with TWSTFT measurements; the full-ISL clock products show high accuracy and continuity. The BDS3 PHMs and rubidium clocks both have a small clock rate drift of 10–20 s/s2. The frequency stability of the BDS3 PHMs and some rubidium clocks is approximately 6–9 × 10–15 at 1-day intervals. A linear model is suitable for these small-drift clocks, while a quadratic model is essential for the other rubidium clocks. Applying the full-ISL clock prediction method improves the RMS of the 24 h prediction error from 0.88 to 0.75 ns for PHMs and from 2.62 to 1.64 ns for rubidium clocks. The estimated ISL hardware delay STDs are less than 0.2 ns, and the prediction errors evaluated with TWSTFT clock observations are similar to those evaluated with Ka-band clock observations. [ABSTRACT FROM AUTHOR]

This paper demonstrates the capability of NAO humanoid robot to interact with hearing impaired persons using Indian Sign Language (ISL). Principal contributions of the paper are: wavelet descriptor has been applied to extracting moment invariant shape future of hand gestures and possibility theory (PT) has been used for classification of gestures. Preprocessing and extraction of overlapping frames (start and end point of each gesture) are the other major events which have been solved using background modeling and novel gradient method. We have shown that the overlapping frames are helpful for fragmenting a continuous ISL gesture into isolated gestures. These isolated gestures are further processed and classified. During the segmentation process some of the geometrical features like shape and orientation of hand are deformed, which has been overcome by extracting a new moment invariant feature through wavelet descriptor. These features are then combined with the other two features (orientation and speed) and are classified using PT. Here we use PT in place of probability theory because possibility deals with the problem of uncertainty and impression whereas probability handles only uncertainty issues. Experiments have been performed on 20 sentences of continuous ISL gestures having 4000 samples where each sentence having 20 instances. In this dataset 50% samples have been used for training and 50% have been used for testing. From analysis of results we found that the proposed approach gives 92% classification accuracy with 20 subjects on continuous ISL gestures. This result has been compared with the results obtained with other classifiers like Hidden Markov Model and KNN and found 10% increment in the classification rate with proposed approach. These classified gestures are then combined for generating a sentence in the text format which is being matched with the knowledge database of NAO robot which has also increased the classification accuracy. These sentences are further converted in the form of speech or gesture using NAO robot. [ABSTRACT FROM AUTHOR]

The BeiDou Navigation Satellite System is expected to provide a global positioning and navigation service by 2020. To achieve this goal, the new-generation navigation satellites that have been launched since March 2015 are equipped with inter-satellite links (ISLs), with the objective of testing new navigation signals and the ISLs themselves. Using these new-generation navigation satellites and several ground facilities in China, a combined orbit determination experiment was carried out during August 2016. The orbit mechanical model, orbit determination method, and accuracy evaluation method used in this experiment are presented here. The accuracy of the combined orbit determination method is evaluated, and the performance-related improvements resulting from the ISLs are analyzed. The performance of orbit determination has been increased about 37-76% for different satellites in orbit-only signal-in-space range error (orbit-only SISRE). [ABSTRACT FROM AUTHOR]

The main goal of this paper is to demonstrate the multifractal behavior of the ionospheric plasma signals recorded by the ISL instrument installed onboard of the DEMETER satellite before the L'Aquila earthquake of 2009. Multifractal analysis is performed using the so-called the wavelet transform modulus maxima lines (WTMM) method. Signals to be analyzed are: density of electrons and ions, temperature of electrons, and the potential of the plasma. WTMM analysis of the data recorded during April 4, 2009 which recognizes many ionospheric disturbances before the L'Aquila earthquake clearly shows the multifractal behavior of the ionosphere plasma physical response. WTMM analysis of data recorded by the DEMETER satellite two months after the L'Aquila earthquake main shock shows the monofractal behavior of the plasma response. [ABSTRACT FROM AUTHOR]

Assessing joint function following trauma and its inter-relation with degenerative changes requires an understanding of the normal state of structural loading in the joint. Very few studies have attempted to reproduce joint specific in vivo motions in vitro to quantify the actual loads carried by different tissues within the knee joint. The most significant challenge in this area is the very high sensitivity of the loads in joint structures to motion reproduction accuracy. A novel testing platform for assessing knee joint mechanics is described, comprised of a highly accurate (0.3 ± 0.1 mm, 0.3 ± 0.1°) six-degree-of-freedom (6-DOF) instrumented spatial linkage (ISL) for in vivo joint kinematic assessments and a unique 6-DOF parallel robotic manipulator. A position feedback system (ISL and position controller) is used for accurate reproduction of in vivo joint motions and estimation of ' in situ' joint/tissue loads. The parallel robotic manipulator provides excellent stiffness and repeatability in reproducing physiological motions in 6-DOF, compared to the commonly used serial robots. The position feedback system provides real-time feedback data to the robot to reproduce in vivo motions and significantly enhances motion reproduction accuracy by adjusting for robot end-effector movements. Using this combined robot-ISL system, in vivo motions can be reproduced in vitro with very high accuracy (0.1 mm, 0.1°). Our results indicate that this level of accuracy is essential for meaningful estimation of tissue loads during gait. Using this novel testing platform, we have determined the normal load-carrying characteristics of different tissues within the ovine knee joint. The application of this testing system will continue to increase our understanding of normal and pathological joint states. [ABSTRACT FROM AUTHOR]

This paper studies the key techniques of the measurement and communication system for inter-satellite links (ISLs) of global navigation satellite system. A fixed link topology is designed based on the analysis of inter-satellite geometric properties and spatial parameters of the standard Walker24/3/2 constellation. This design can achieve full network coverage with small number of hops, significantly reduce the number of ISLs, and enhance the feasibility and reliability of the system. A new time-division duplex mode, as well as an integrated measurement and communication scheme, is proposed based on the designed topology. Furthermore, mathematical formulas, error models, and modification methods regarding two-way ranging and time synchronization algorithms using spread spectrum non-coherent data frame for this new system are comprehensively discussed. Theoretical analysis and simulation studies demonstrate that our design, compared with current GPS systems, has higher ranging and time synchronization precision, improved measurement efficiency, and higher channel utilization ratio and data transmission rate. It has no restrictions of constellation configuration, making it suitable for both MEO and the future MEO/GEO hybrid constellations. The results in this paper can serve as strong technical support for the next generation of GNSS ISL. [ABSTRACT FROM AUTHOR]

In the design of new constellation configurations or research of existing constellation performance, the connectivity and robustness of inter-satellite links (ISL) are needed for analysis. In this paper, graph theory is used to analyze the connectivity and robustness of the ISL in constellations, which are measured under the requirements of a short average distance and a small range of ISL azimuth angles, elevation angles and distances. The method to determine ISL connectivity by using the adjacency matrix of graph theory is put forward for the first time, and the standards of the ISL performance are given using: the number of ways between any two satellites, cutting point, cutting edge, k-connectivity degree and k-edge connectivity degree of graph theory. Finally, in the simulation, the ISLs in the Walker 24/6/1 constellation and the ISLs in the Walker 24/3/1 constellation are established from the optimal perspective of the azimuth angle, elevation angle and distance, and the characteristics of ISL in the Walker 24/6/1 and Walker 24/3/1 constellations are compared. The conclusions of this paper can be used as a reference for the design of new constellation configurations and analysis of existing ISLs. [ABSTRACT FROM AUTHOR]

Considering that gravitational force might deviate from Newton's inverse-square law (ISL) and become much stronger in small scale, we propose a kind of optical spectroscopy experiment to detect this possible deviation and take electronic, muonic and tauonic hydrogen atoms as examples. This experiment might be used to indirectly detect the deviation of ISL down to nanometer scale and to explore the possibility of three extra dimensions in ADD's model, while current direct gravity tests cannot break through micron scale and go beyond two extra dimensions scenario. [ABSTRACT FROM AUTHOR]

In this paper, the performance analysis of the inter-satellite optical wireless communication system (IsOWC) is carried out in presence of optical space channel. Here the proposed model is a 16 × 100 Gbps dense multiplexed IsOWC. The dual polarized quadrature phase shift keying (DP-QPSK) modulation is used for improving the optical signal to noise ratio tolerance of the system. Further, the spectral efficiency and the receiver sensitivity is improved by incorporating the coherent orthogonal frequency division multiplexing (CO-OFDM) technique in the proposed IsOWC system. The performance of the system is evaluated by bit error rate (BER), error vector magnitude percentage, received signal power, constellation diagram. A comparative study has been carried out between different modulation techniques such as quadrature phase shift keying and DP-QPSK used in IsOWC system. It is observed that, an inter-satellite distance of 15,600 km is obtained with the proposed model at 100 Gbps for a targeted forward error correction log of BER value of − 2.42 or BER of 3.8 × 10 - 3 . The maximum possible data rate for different inter and intra orbit satellite has been calculated. Also, the maximum possible transceiver distance has been calculated for different data rates. The integration of two advanced technologies such as DP-QPSK modulation with CO-OFDM technique in the proposed model may impel the market demands for high bandwidth intensive and high data rate applications. [ABSTRACT FROM AUTHOR]