Autonomous navigation for small body landing using optical and inter-spacecraft measurements

<p>&#160; &#160;In small body exploration mission, the uncertainty of the target characteristics and the special weak gravitational environment put forward higher requirements for the optical autonomous navigation accuracy of the probe and the detection ability of the navigation sensor. Narrow Angel Sensor(Hereinafter referred to as NAS), as the key instrument of China&#8217;s first small body exploration mission, has both optical autonomous navigation function and scientific observation ability, and it must give consideration to both near and far, and achieve breakthroughs in dynamic range, detection sensitivity, pointing measurement accuracy, angular resolution and spectral observation ability. The specific performance is as follows: To capture and track Near Earth Asteroids 2016HO3 from tens of thousands of kilometers, NAS is required to have the ability of point target detection, and the detection sensitivity is better than MV10, and &#160;the accuracy of pointing measurement is better than 1 &#8243;. As the probe approaches the target, NAS must be able to clearly image the shape and surface texture of 2016HO3, so as to obtain the motion parameters such as the spin axis and rotation period of the target. In remote sensing and descending stage, the mission requires NAS to be able to carry out global centimeter scale and landing area millimeter scale multi-spectral observation of the target, and optical navigation uses high-resolution images to construct landmark feature library, so as to realize terrain relative navigation; meanwhile, the image is used to provide data support for the scientific research of the target topography, spectral characteristics and surface material composition analysis.</p> <p>&#160; &#160;NAS adopts split design, and the detector part is composed of front door, baffle, focusing optical system, filter wheel, image processing circuit, and motor drive circuit, the algorithm is implemented in the image navigation processing unit. The prototype of the instruments has been developed, and the function and performances such as MTF, detection sensitivity, pointing measurement accuracy etc were verified. The instrument achieved expected design objectives, &#160;and can meet the requirements of optical autonomous navigation and scientific observation for China&#8217;s small body exploration mission.</p>

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The Impact of Missing and Error-Prone Auxiliary Information on Sparse-Matrix Sub-Population Parameter Estimates

Methodology ◽

10.1027/1614-2241/a000095 ◽

2015 ◽

Vol 11 (3) ◽

pp. 89-99 ◽

Cited By ~ 1

Author(s):

Leslie Rutkowski ◽

Yan Zhou

Keyword(s):

Sparse Matrix ◽

Small Body ◽

Auxiliary Information ◽

Poor Quality ◽

Quality Data ◽

Estimation Methods ◽

Parameter Estimates ◽

Population Parameter ◽

Conditioning Model ◽

The Impact

Abstract. Given a consistent interest in comparing achievement across sub-populations in international assessments such as TIMSS, PIRLS, and PISA, it is critical that sub-population achievement is estimated reliably and with sufficient precision. As such, we systematically examine the limitations to current estimation methods used by these programs. Using a simulation study along with empirical results from the 2007 cycle of TIMSS, we show that a combination of missing and misclassified data in the conditioning model induces biases in sub-population achievement estimates, the magnitude and degree to which can be readily explained by data quality. Importantly, estimated biases in sub-population achievement are limited to the conditioning variable with poor-quality data while other sub-population achievement estimates are unaffected. Findings are generally in line with theory on missing and error-prone covariates. The current research adds to a small body of literature that has noted some of the limitations to sub-population estimation.

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Risk Factors for Bleeding during Treatment of Acute Venous Thromboembolism

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650643 ◽

1996 ◽

Vol 76 (05) ◽

pp. 682-688 ◽

Cited By ~ 33

Author(s):

Jos P J Wester ◽

Harold W de Valk ◽

Karel H Nieuwenhuis ◽

Catherine B Brouwer ◽

Yolanda van der Graaf ◽

...

Keyword(s):

Risk Factors ◽

Venous Thromboembolism ◽

Surface Area ◽

Body Surface Area ◽

Body Surface ◽

Small Body ◽

Bleeding Risk ◽

Risk Scores ◽

Risk Of Bleeding ◽

Acute Venous Thromboembolism

Summary Objective: Identification of risk factors for bleeding and prospective evaluation of two bleeding risk scores in the treatment of acute venous thromboembolism. Design: Secondary analysis of a prospective, randomized, assessor-blind, multicenter clinical trial. Setting: One university and 2 regional teaching hospitals. Patients: 188 patients treated with heparin or danaparoid for acute venous thromboembolism. Measurements: The presenting clinical features, the doses of the drugs, and the anticoagulant responses were analyzed using univariate and multivariate logistic regression analysis in order to evaluate prognostic factors for bleeding. In addition, the recently developed Utrecht bleeding risk score and Landefeld bleeding risk index were evaluated prospectively. Results: Major bleeding occurred in 4 patients (2.1%) and minor bleeding in 101 patients (53.7%). For all (major and minor combined) bleeding, body surface area ≤2 m2 (odds ratio 2.3, 95% Cl 1.2-4.4; p = 0.01), and malignancy (odds ratio 2.4, 95% Cl 1.1-4.9; p = 0.02) were confirmed to be independent risk factors. An increased treatment-related risk of bleeding was observed in patients treated with high doses of heparin, independent of the concomitant activated partial thromboplastin time ratios. Both bleeding risk scores had low diagnostic value for bleeding in this sample of mainly minor bleeders. Conclusions: A small body surface area and malignancy were associated with a higher frequency of bleeding. The bleeding risk scores merely offer the clinician a general estimation of the risk of bleeding. In patients with a small body surface area or in patients with malignancy, it may be of interest to study whether limited dose reduction of the anticoagulant drug may cause less bleeding without affecting efficacy.

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Multisensor Concept for Autonomous Navigation of Unmanned Systems in GNSS-denied Environments

Proceedings of the 30th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2017) ◽

10.33012/2017.15410 ◽

2017 ◽

Author(s):

Mario G�bel ◽

Thomas Kr�ger ◽

Stefan Nowak ◽

Jan Meifarth ◽

Ulf Bestmann

Keyword(s):

Autonomous Navigation ◽

Unmanned Systems

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Creating a ‘Masala’ Self: Bicultural Identity in Desi Young Adult Novels

International Research in Children s Literature ◽

10.3366/ircl.2010.0102 ◽

2010 ◽

Vol 3 (2) ◽

pp. 119-133 ◽

Cited By ~ 1

Author(s):

Michelle Superle

Keyword(s):

Young Adult ◽

Young People ◽

Identity Development ◽

Small Body ◽

The United States ◽

Young Adult Fiction ◽

Bicultural Identity ◽

The United Kingdom ◽

Institutional Forces ◽

Cultural Identity Development

In the past two decades, the previously silent voices of diasporic Indian writers for young people have emerged, and a small body of texts has begun to develop in the United States and the United Kingdom. One of the major preoccupations of these texts is cultural identity development, especially in the novels published for a young adult audience, which often feature protagonists in the throes of an identity crisis. For example, the novels The Roller Birds of Rampur (1991) by Indi Rana, Born Confused (2002) by Tanuja Desai Hidier, and The Not-So-Star-Spangled Life of Sunita Sen (2005) by Mitali Perkins all focus on an adolescent girl coping with her bicultural identity with angst and confusion, and delineate the ways her self-concept and relationships are affected. The texts are empowering in their suggestion that young people have the agency to explore and create their own balanced bicultural identities, but like other young adult fiction, they ultimately situate adolescents within insurmountable institutional forces that are much more powerful than any individual.

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The Transnational Women's Rights Movement and the World Economy

Sociology of Development ◽

10.1525/sod.2020.6.2.145 ◽

2020 ◽

Vol 6 (2) ◽

pp. 145-173 ◽

Cited By ~ 1

Author(s):

Heidi E. Rademacher

Keyword(s):

Women's Rights ◽

Small Body ◽

World System ◽

World Society ◽

Women’S Rights ◽

Social Movement Organizations ◽

Global Movement ◽

Negative Effect ◽

Society Perspective ◽

The Impact

Promoting the ratification of the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW) was a key objective of the transnational women's movement of the 1980s and 1990s. Yet, few studies examine what factors contribute to ratification. The small body of literature on this topic comes from a world-society perspective, which suggests that CEDAW represented a global shift toward women's rights and that ratification increased as international NGOs proliferated. However, this framing fails to consider whether diffusion varies in a stratified world-system. I combine world-society and world-systems approaches, adding to the literature by examining the impact of women's and human rights transnational social movement organizations on CEDAW ratification at varied world-system positions. The findings illustrate the complex strengths and limitations of a global movement, with such organizations having a negative effect on ratification among core nations, a positive effect in the semiperiphery, and no effect among periphery nations. This suggests that the impact of mobilization was neither a universal application of global scripts nor simply representative of the broad domination of core nations, but a complex and diverse result of civil society actors embedded in a politically stratified world.

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Management of Intraoperative Fluid Balance and Blood Conservation Techniques in Adult Cardiac Surgery

The Heart Surgery Forum ◽

10.1532/hsf98.2010111 ◽

2011 ◽

Vol 14 (1) ◽

pp. 28 ◽

Cited By ~ 10

Author(s):

George Vretzakis ◽

Athina Kleitsaki ◽

Diamanto Aretha ◽

Menelaos Karanikolas

Keyword(s):

Cardiac Surgery ◽

Blood Cell ◽

Fluid Balance ◽

Blood Product ◽

Blood Donation ◽

Autologous Blood ◽

Small Body ◽

Risk Indicators ◽

Blood Transfusions ◽

Blood Conservation

Blood transfusions are associated with adverse physiologic effects and increased cost, and therefore reduction of blood product use during surgery is a desirable goal for all patients. Cardiac surgery is a major consumer of donor blood products, especially when cardiopulmonary bypass (CPB) is used, because hematocrit drops precipitously during CPB due to blood loss and blood cell dilution. Advanced age, low preoperative red blood cell volume (preoperative anemia or small body size), preoperative antiplatelet or antithrombotic drugs, complex or re-operative procedures or emergency operations, and patient comorbidities were identified as important transfusion risk indicators in a report recently published by the Society of Cardiovascular Anesthesiologists. This report also identified several pre- and intraoperative interventions that may help reduce blood transfusions, including off-pump procedures, preoperative autologous blood donation, normovolemic hemodilution, and routine cell saver use.A multimodal approach to blood conservation, with highrisk patients receiving all available interventions, may help preserve vital organ perfusion and reduce blood product utilization. In addition, because positive intravenous fluid balance is a significant factor affecting hemodilution during cardiac surgery, especially when CPB is used, strategies aimed at limiting intraoperative fluid balance positiveness may also lead to reduced blood product utilization.This review discusses currently available techniques that can be used intraoperatively in an attempt to avoid or minimize fluid balance positiveness, to preserve the patient's own red blood cells, and to decrease blood product utilization during cardiac surgery.

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