Preliminary Optical Performance Analysis of the Space Interferometer Mission Using an Integrated Modeling Methodology

2000 ◽  
Author(s):  
Ipek Basdogan ◽  
Robert Grogan ◽  
Andy Kissil ◽  
Norbert Sigrist ◽  
Lisa Sievers
Keyword(s):  
System Design ◽  
System Modeling ◽  
Experimental Studies ◽  
Integrated Modeling ◽  
Optical Performance ◽  
Reaction Wheel ◽  
Space Interferometer ◽  
Modeling Methodology ◽  
Reference Design ◽  
The Impact

Abstract The Space Interferometer Mission (SIM) scheduled for launch in 2008, is one of the premiere missions in the Origins Program, NASA’s endeavor to understand the origins of the galaxies, of planetary systems around distant stars, and perhaps the origins of life itself. The precise tolerance required by the SIM instrument facilitates the investigation of many design options, trades, and methods for minimizing interaction between the actively controlled optics and the structure. One of the activities that addresses these technological challenges is the integrated modeling methodology development and validation at Jet Propulsion Laboratory (JPL). The methodology integrates structural, optical, and control system modeling into a common computational environment and enables end-to-end performance evaluation of complex optomechanical systems. This paper provides an overview of the integrated modeling methodology and introduces the most recent SIM Reference Design model. The SIM integrated model is used in system requirement trade studies and performance analyses to support the overall system design and ongoing error budget efforts. Optical performance in interferometry is typically measured in terms of optical pathlength difference (OPD) and differential wavefront tilt (DWT). This paper focuses on the OPD performance metric and investigates the OPD jitter resulting from reaction wheel assembly (RWA) disturbances. The RWA is the largest anticipated disturbance source on the spacecraft. Therefore, assessing the impact of the wheel disturbance frequency content and magnitude levels on the optical performance is essential for the success of the mission. Broadband and discrete frequency models of a reaction wheel are used to perform the disturbance analysis. The overall system design can benefit from such analysis results by identifying the critical regions in the frequency domain and decoupling the dynamics of the optical and structural components from the disturbance spectrum and the control bandwidth. The preliminary performance results show that the current SIM Reference Design meets the mission requirements with respect to RWA induced disturbances. However, some of the modeling assumptions and component models must be validated by experimental studies before the subsystem requirements are finalized.

Воздействиеультразвуковогополянадинамическуювязкостьводы

2019 ◽  
pp. 27-29
Author(s):  
P. Vikulin ◽  
K. Khlopov ◽  
M. Cherkashin
Keyword(s):  
Dynamic Viscosity ◽  
Experimental Studies ◽  
Ultrasonic Field ◽  
Maximum Effect ◽  
Ultrasonic Frequency ◽  
Ultrasonic Vibrations ◽  
Wastewater Disposal ◽  
Laboratory Setup ◽  
Sonic Treatment ◽  
The Impact

Enhancing water purification processes is provided by various methods including physical ones, in particular, exposure to ultrasonic vibrations. The change in the dynamic viscosity of water affects the rate of deposition of particles in the aquatic environment which can be used in natural and wastewater treatment. At the Department Water Supply and Wastewater Disposal of the National Research Moscow State University of Civil Engineering experimental studies were conducted under laboratory conditions to study the effect of ultrasound on the change in the dynamic viscosity of water. A laboratory setup has been designed consisting of an ultrasonic frequency generator of the relative intensity, a transducer (concentrator) that transmits ultrasonic vibrations to the source water, and sonic treatment tanks. Experimental studies on the impact of the ultrasonic field in the cavitation mode on the dynamic viscosity of the aqueous medium were carried out the exposure time was obtained to achieve the maximum effect.Интенсификация процессов очистки воды осуществляется с помощью различных методов, в том числе и физических, в частности воздействием ультразвуковых колебаний. Изменение динамической вязкости воды влияет на скорость осаждения частиц в водной среде, что может быть использовано в процессах очистки природных и сточных вод. На кафедре Водоснабжение и водоотведение Национального исследовательского Московского государственного строительного университета в лабораторных условиях проведены экспериментальные исследования по изучению влияния ультразвука на изменение динамической вязкости воды. Разработана схема лабораторной установки, состоящая из генератора ультразвуковых частот с соответствующей интенсивностью, преобразователя (концентратора), передающего ультразвуковые колебания в исходную воду, и емкости для озвучивания. Выполнены экспериментальные исследования по влиянию ультразвукового поля в режиме кавитации на динамическую вязкость водной среды, получено время экспозиции для достижения максимального эффекта.

Family Influences on Youth Offending

2018 ◽  
pp. 377-403
Author(s):  
Abigail A. Fagan ◽  
Kristen M. Benedini
Keyword(s):  
Life Course ◽  
Family Environment ◽  
Parenting Practices ◽  
Experimental Studies ◽  
The United States ◽  
Parental Violence ◽  
Youth Delinquency ◽  
The Impact ◽  
Children’S Exposure

This chapter reviews the degree to which empirical evidence demonstrates that families influence youth delinquency. Because they are most likely to be emphasized in life-course theories, this chapter focuses on parenting practices such as parental warmth and involvement, supervision and discipline of children, and child maltreatment. It also summarizes literature examining the role of children's exposure to parental violence, family criminality, and young (teenage) parents in affecting delinquency. Because life-course theories are ideally tested using longitudinal data, which allow examination of, in this case, the impact of parenting practices on children's subsequent behaviors, this chapter focuses on evidence generated from prospective studies conducted in the United States and other countries. It also discusses findings from experimental studies designed to reduce youth substance use and delinquency by improving the family environment.

scholarly journals Anthropomorphic Strategies Promote Wildlife Conservation through Empathy: The Moderation Role of the Public Epidemic Situation

2021 ◽  
Vol 18 (7) ◽  
pp. 3565
Author(s):  
Dan Yue ◽  
Zepeng Tong ◽  
Jianchi Tian ◽  
Yang Li ◽  
Linxiu Zhang ◽  
...  
Keyword(s):  
College Students ◽  
Behavioral Intention ◽  
Wildlife Conservation ◽  
Negative Emotion ◽  
Public Awareness ◽  
Negative Emotions ◽  
Experimental Studies ◽  
Wildlife Trade ◽  
Illegal Wildlife Trade ◽  
The Impact

The global illegal wildlife trade directly threatens biodiversity and leads to disease outbreaks and epidemics. In order to avoid the loss of endangered species and ensure public health security, it is necessary to intervene in illegal wildlife trade and promote public awareness of the need for wildlife conservation. Anthropomorphism is a basic and common psychological process in humans that plays a crucial role in determining how a person interacts with other non-human agents. Previous research indicates that anthropomorphizing nature entities through metaphors could increase individual behavioral intention of wildlife conservation. However, relatively little is known about the mechanism by which anthropomorphism influences behavioral intention and whether social context affects the effect of anthropomorphism. This research investigated the impact of negative emotions associated with a pandemic situation on the effectiveness of anthropomorphic strategies for wildlife conservation across two experimental studies. Experiment 1 recruited 245 college students online and asked them to read a combination of texts and pictures as anthropomorphic materials. The results indicated that anthropomorphic materials could increase participants’ empathy and decrease their wildlife product consumption intention. Experiment 2 recruited 140 college students online and they were required to read the same materials as experiment 1 after watching a video related to epidemics. The results showed that the effect of wildlife anthropomorphization vanished if participants’ negative emotion was aroused by the video. The present research provides experimental evidence that anthropomorphic strategies would be useful for boosting public support for wildlife conservation. However, policymakers and conservation organizations must be careful about the negative effects of the pandemic context, as the negative emotions produced by it seems to weaken the effectiveness of anthropomorphic strategies.

scholarly journals Formation of an Export-Oriented Agricultural Economy and Regional Open Innovations

2021 ◽  
Vol 7 (1) ◽  
pp. 32
Author(s):  
Victor L. Shabanov ◽  
Marianna Ya Vasilchenko ◽  
Elena A. Derunova ◽  
Andrey P. Potapov
Keyword(s):  
Agricultural Economy ◽  
Institutional Management ◽  
Agricultural Exports ◽  
Modeling Methodology ◽  
Fixed Assets ◽  
Analysis Application ◽  
The Impact ◽  
The Relationship

The aim of the work is to find relevant indicators for assessing the relationship between investments in fixed assets in agriculture, gross output of the industry, and agricultural exports using tools for modeling the impact of innovation and investment development on increasing production and export potential in the context of the formation of an export-oriented agricultural economy. The modeling methodology and the proposed estimating and forecasting tools for diagnosing and monitoring the state of sectoral and regional innovative agricultural systems are used to analyze the relationship between investments in fixed assets in agriculture, gross output of the industry, and agricultural exports based on the construction of the classification of Russian regions by factors that aggregate these features to diagnose incongruence problems and to improve institutional management in regional innovative export-oriented agrosystems. Based on the results of the factor analysis application, an underestimated role of indicators of investment in agriculture, the intensity and efficiency of agricultural production, were established. Based on the results of the cluster analysis, the established five groups of regions were identified, with significant differences in the level of investment in agriculture, the volume of production of the main types of agricultural products, and the export and exported food. The research results are of practical value for use in improving institutional management when planning reforms and transformations of regional innovative agrosystems.

scholarly journals Image Statistics Preserving Encrypt-then-Compress Scheme Dedicated for JPEG Compression Standard

Entropy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 421
Author(s):  
Dariusz Puchala ◽  
Kamil Stokfiszewski ◽  
Mykhaylo Yatsymirskyy
Keyword(s):  
Statistical Analysis ◽  
Image Encryption ◽  
Experimental Studies ◽  
Quality Measures ◽  
Input Image ◽  
Jpeg Compression ◽  
Image Statistics ◽  
Compression Stage ◽  
Wide Range ◽  
The Impact

In this paper, the authors analyze in more details an image encryption scheme, proposed by the authors in their earlier work, which preserves input image statistics and can be used in connection with the JPEG compression standard. The image encryption process takes advantage of fast linear transforms parametrized with private keys and is carried out prior to the compression stage in a way that does not alter those statistical characteristics of the input image that are crucial from the point of view of the subsequent compression. This feature makes the encryption process transparent to the compression stage and enables the JPEG algorithm to maintain its full compression capabilities even though it operates on the encrypted image data. The main advantage of the considered approach is the fact that the JPEG algorithm can be used without any modifications as a part of the encrypt-then-compress image processing framework. The paper includes a detailed mathematical model of the examined scheme allowing for theoretical analysis of the impact of the image encryption step on the effectiveness of the compression process. The combinatorial and statistical analysis of the encryption process is also included and it allows to evaluate its cryptographic strength. In addition, the paper considers several practical use-case scenarios with different characteristics of the compression and encryption stages. The final part of the paper contains the additional results of the experimental studies regarding general effectiveness of the presented scheme. The results show that for a wide range of compression ratios the considered scheme performs comparably to the JPEG algorithm alone, that is, without the encryption stage, in terms of the quality measures of reconstructed images. Moreover, the results of statistical analysis as well as those obtained with generally approved quality measures of image cryptographic systems, prove high strength and efficiency of the scheme’s encryption stage.

Lighting energy performance determination in office environments through implementation of EN 15193-1 for Turkey

2021 ◽  
pp. 147715352098742
Author(s):  
FŞ Yilmaz
Keyword(s):  
System Design ◽  
Architectural Design ◽  
Office Buildings ◽  
Energy Requirements ◽  
System Control ◽  
Lighting System ◽  
Artificial Lighting ◽  
Design Alternatives ◽  
Lighting Energy ◽  
The Impact

Office buildings are building typologies where efficient and optimal use of lighting energy is crucial while providing comfortable visual environments. The purpose of this study is to explore the impact of diverse architectural design alternatives on lighting energy requirements and lighting energy saving possibilities through a case study. In this study, a total of 3888 design alternatives are investigated in a comparative way in terms of daylighting system design alternatives, artificial lighting system design scenarios, artificial lighting system control types and shading system control options. Introducing the adaptation process of the EN 15193-1:2017 standard for Turkey’s specific climatic and geographical conditions and considering diverse lighting design scenarios, results of this parametric study aim to underline the significance of architectural design strategies in office buildings for the reduction of lighting energy requirements.

scholarly journals Ethanol/Gasoline Blends as Alternative Fuel in Last Generation Spark-Ignition Engines: A Review on CO and HC Engine Out Emissions

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4034
Author(s):  
Paolo Iodice ◽  
Massimo Cardone
Keyword(s):  
Physicochemical Properties ◽  
Alternative Fuels ◽  
Experimental Studies ◽  
Alternative Fuel ◽  
Exhaust Emissions ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Spark Ignition Engines ◽  
The Impact

Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to investigate the effect on engine out emissions and combustion efficiency. In the next section, this article focuses on the impact of ethanol/gasoline fuels on CO and HC formation. Many studies related to combustion characteristics and exhaust emissions in spark-ignition engines fueled with ethanol/gasoline fuels are thus discussed in detail. Most of these experimental investigations conclude that the addition of ethanol with gasoline fuel mixtures can really decrease the CO and HC exhaust emissions of last generation spark-ignition engines in several operating conditions.

scholarly journals Between Level Up and Game Over: A Systematic Literature Review of Gamification in Education

2021 ◽  
Vol 13 (4) ◽  
pp. 2247 ◽  
Author(s):  
Ana Manzano-León ◽  
Pablo Camacho-Lazarraga ◽  
Miguel A. Guerrero ◽  
Laura Guerrero-Puerta ◽  
José M. Aguilar-Parra ◽  
...  
Keyword(s):  
Systematic Review ◽  
Academic Performance ◽  
Game Design ◽  
Learning Strategy ◽  
Experimental Studies ◽  
Quasi Experimental ◽  
Current Lines ◽  
Meta Analyses ◽  
Game Elements ◽  
The Impact

Educational gamification consists of the use of game elements and game design techniques in the educational context. The objective of this study is to examine the existing evidence on the impact of educational gamification on student motivation and academic performance in the last five years in order to analyze its distribution over time, educational level, variables, and most used game elements, and know the advantages of its implementation in the classroom. For this, a systematic review is proposed through the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) methodology in three multidisciplinary databases, through an exhaustive search with inclusion and exclusion criteria on quantitative experimental studies that explore gamification in educational centers, which provide information about the most current lines of research. Fourteen studies were included in this review. These used experimental or quasi-experimental designs. Most of them report gamification as a valid learning strategy. The results support the conclusion that educational gamification has a potential impact on the academic performance, commitment, and motivation of students. Therefore, this study implies the need to expand research on the needs and challenges of students when learning with gamified techniques.

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