WorldWideScience

Sample records for robustly positively related

  1. Robust Position Control of Electro-mechanical Systems

    OpenAIRE

    Rong Mei; Mou Chen

    2013-01-01

    In this work, the robust position control scheme is proposed for the electro-mechanical system using the disturbance observer and backstepping control method. To the external unknown load of the electro-mechanical system, the nonlinear disturbance observer is given to estimate the external unknown load. Combining the output of the developed nonlinear disturbance observer with backstepping technology, the robust position control scheme is proposed for the electro-mechanical system. The stabili...

  2. EnTracked: Energy-Efficient Robust Position Tracking for Mobile Devices

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Jensen, Jakob Langdal; Godsk, Torben

    2009-01-01

    conditions and mobility, schedules position updates to both minimize energy consumption and optimize robustness. The realized system tracks pedestrian targets equipped with GPS-enabled devices. The system is configurable to realize different trade-offs between energy consumption and robustness. We provide...... of the mobile device. Furthermore, tracking has to robustly deliver position updates when faced with changing conditions such as delays due to positioning and communication, and changing positioning accuracy. This work proposes EnTracked --- a system that, based on the estimation and prediction of system...... extensive experimental results by profiling how devices consume power, by emulation on collected data and by validation in several real-world deployments. Results from this profiling show how a device consumes power while tracking its position. Results from the emulation indicate that the system can...

  3. Robust hydraulic position controller by a fuzzy state controller

    International Nuclear Information System (INIS)

    Zhao, T.; Van der Wal, A.J.

    1994-01-01

    In nuclear industry, one of the most important design considerations of controllers is their robustness. Robustness in this context is defined as the ability of a system to be controlled in a stable way over a wide range of system parameters. Generally the systems to be controlled are linearized, and stability is subsequently proven for this idealized system. By combining classical control theory and fuzzy set theory, a new kind of state controller is proposed and successfully applied to a hydraulic position servo with excellent robustness against variation of system parameters

  4. Robust control design for the plasma horizontal position control on J-TEXT Tokamak

    International Nuclear Information System (INIS)

    Yu, W.Z.; Chen, Z.P.; Zhuang, G.; Wang, Z.J.

    2013-01-01

    It is extremely important for tokamak to control the plasma position during routine discharge. However, the model of plasma in tokamak usually contains much of the uncertainty, such as structured uncertainties and unmodeled dynamics. Compared with the traditional PID control approach, robust control theory is more suitable to handle this problem. In the paper, we propose a H ∞ robust control scheme to control the horizontal position of plasma during the flat-top phase of discharge on Joint Texas Experimental Tokamak (J-TEXT) tokamak. First, the model of our plant for plasma horizontal position control is obtained from the position equilibrium equations. Then the H ∞ robust control framework is used to synthesize the controller. Based on this, an H ∞ controller is designed to minimize the regulation/tracking error. Finally, a comparison study is conducted between the optimized H ∞ robust controller and the traditional PID controller in simulations. The simulation results of the H ∞ robust controller show a significant improvement of the performance with respect to those obtained with traditional PID controller, which is currently used on our machine

  5. Robust Solvers for Symmetric Positive Definite Operators and Weighted Poincaré Inequalities

    KAUST Repository

    Efendiev, Yalchin; Galvis, Juan; Lazarov, Raytcho; Willems, Joerg

    2012-01-01

    An abstract setting for robustly preconditioning symmetric positive definite (SPD) operators is presented. The term "robust" refers to the property of the condition numbers of the preconditioned systems being independent of mesh parameters

  6. Robustness-related issues in speaker recognition

    CERN Document Server

    Zheng, Thomas Fang

    2017-01-01

    This book presents an overview of speaker recognition technologies with an emphasis on dealing with robustness issues. Firstly, the book gives an overview of speaker recognition, such as the basic system framework, categories under different criteria, performance evaluation and its development history. Secondly, with regard to robustness issues, the book presents three categories, including environment-related issues, speaker-related issues and application-oriented issues. For each category, the book describes the current hot topics, existing technologies, and potential research focuses in the future. The book is a useful reference book and self-learning guide for early researchers working in the field of robust speech recognition.

  7. Robust Solar Position Sensor for Tracking Systems

    DEFF Research Database (Denmark)

    Ritchie, Ewen; Argeseanu, Alin; Leban, Krisztina Monika

    2009-01-01

    The paper proposes a new solar position sensor used in tracking system control. The main advantages of the new solution are the robustness and the economical aspect. Positioning accuracy of the tracking system that uses the new sensor is better than 1°. The new sensor uses the ancient principle...... of the solar clock. The sensitive elements are eight ordinary photo-resistors. It is important to note that all the sensors are not selected simultaneously. It is not necessary for sensor operating characteristics to be quasi-identical because the sensor principle is based on extreme operating duty measurement...... (bright or dark). In addition, the proposed solar sensor significantly simplifies the operation of the tracking control device....

  8. Adaptive robust Kalman filtering for precise point positioning

    International Nuclear Information System (INIS)

    Guo, Fei; Zhang, Xiaohong

    2014-01-01

    The optimality of precise point postioning (PPP) solution using a Kalman filter is closely connected to the quality of the a priori information about the process noise and the updated mesurement noise, which are sometimes difficult to obtain. Also, the estimation enviroment in the case of dynamic or kinematic applications is not always fixed but is subject to change. To overcome these problems, an adaptive robust Kalman filtering algorithm, the main feature of which introduces an equivalent covariance matrix to resist the unexpected outliers and an adaptive factor to balance the contribution of observational information and predicted information from the system dynamic model, is applied for PPP processing. The basic models of PPP including the observation model, dynamic model and stochastic model are provided first. Then an adaptive robust Kalmam filter is developed for PPP. Compared with the conventional robust estimator, only the observation with largest standardized residual will be operated by the IGG III function in each iteration to avoid reducing the contribution of the normal observations or even filter divergence. Finally, tests carried out in both static and kinematic modes have confirmed that the adaptive robust Kalman filter outperforms the classic Kalman filter by turning either the equivalent variance matrix or the adaptive factor or both of them. This becomes evident when analyzing the positioning errors in flight tests at the turns due to the target maneuvering and unknown process/measurement noises. (paper)

  9. On Improving the Energy Efficiency and Robustness of Position Tracking for Mobile Devices

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun

    2010-01-01

    position updates when faced with changing conditions such as delays and changing positioning conditions. Previous work has established dynamic tracking systems, such as our EnTracked system, as a solution to address these issues. In this paper we propose a responsibility division for position tracking...... into sensor management strategies and position update protocols and combine the sensor management strategy of EnTracked with position update protocols, which enables the system to further reduce the power consumption with up to 268 mW extending the battery life with up to 36\\%. As our evaluation identify...... that classical position update protocols have robustness weaknesses we propose a method to improve their robustness. Furthermore, we analyze the dependency of tracking systems on the pedestrian movement patterns and positioning environment, and how the power savings depend on the power characteristics...

  10. Robust position estimation of a mobile vehicle

    International Nuclear Information System (INIS)

    Conan, V.

    1994-01-01

    The ability to estimate the position of a mobile vehicle is a key task for navigation over large distances in complex indoor environments such as nuclear power plants. Schematics of the plants are available, but they are incomplete, as real settings contain many objects, such as pipes, cables or furniture, that mask part of the model. The position estimation method described in this paper matches 3-D data with a simple schematic of a plant. It is basically independent of odometer information and viewpoint, robust to noisy data and spurious points and largely insensitive to occlusions. The method is based on a hypothesis/verification paradigm and its complexity is polynomial; it runs in O(m 4 n 4 ), where m represents the number of model patches and n the number of scene patches. Heuristics are presented to speed up the algorithm. Results on real 3-D data show good behaviour even when the scene is very occluded. (authors). 16 refs., 3 figs., 1 tab

  11. On Improving the Energy Efficiency and Robustness of Position Tracking for Mobile Devices

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun

    An important feature of a modern mobile device is that it can position itself and support remote position tracking. To be useful, such position tracking has to be energy-efficient to avoid having a major impact on the battery life of the mobile device. Furthermore, tracking has to robustly deliver...... of different mobile devices....

  12. Hunter-gatherer postcranial robusticity relative to patterns of mobility, climatic adaptation, and selection for tissue economy.

    Science.gov (United States)

    Stock, J T

    2006-10-01

    Human skeletal robusticity is influenced by a number of factors, including habitual behavior, climate, and physique. Conflicting evidence as to the relative importance of these factors complicates our ability to interpret variation in robusticity in the past. It remains unclear how the pattern of robusticity in the skeleton relates to adaptive constraints on skeletal morphology. This study investigates variation in robusticity in claviculae, humeri, ulnae, femora, and tibiae among human foragers, relative to climate and habitual behavior. Cross-sectional geometric properties of the diaphyses are compared among hunter-gatherers from southern Africa (n = 83), the Andaman Islands (n = 32), Tierra del Fuego (n = 34), and the Great Lakes region (n = 15). The robusticity of both proximal and distal limb segments correlates negatively with climate and positively with patterns of terrestrial and marine mobility among these groups. However, the relative correspondence between robusticity and these factors varies throughout the body. In the lower limb, partial correlations between polar second moment of area (J(0.73)) and climate decrease from proximal to distal section locations, while this relationship increases from proximal to distal in the upper limb. Patterns of correlation between robusticity and mobility, either terrestrial or marine, generally increase from proximal to distal in the lower and upper limbs, respectively. This suggests that there may be a stronger relationship between observed patterns of diaphyseal hypertrophy and behavioral differences between populations in distal elements. Despite this trend, strength circularity indices at the femoral midshaft show the strongest correspondence with terrestrial mobility, particularly among males.

  13. Study of Robust Position Recognition System of a Mobile Robot Using Multiple Cameras and Absolute Space Coordinates

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Se Hyun [Amotech, Seoul (Korea, Republic of); Jeon, Young Pil [Samsung Electronics Co., Ltd. Suwon (Korea, Republic of); Park, Jong Ho [Seonam Univ., Namwon (Korea, Republic of); Chong, Kil To [Chon-buk Nat' 1 Univ., Junju (Korea, Republic of)

    2017-07-15

    With the development of ICT technology, the indoor utilization of robots is increasing. Research on transportation, cleaning, guidance robots, etc., that can be used now or increase the scope of future use will be advanced. To facilitate the use of mobile robots in indoor spaces, the problem of self-location recognition is an important research area to be addressed. If an unexpected collision occurs during the motion of a mobile robot, the position of the mobile robot deviates from the initially planned navigation path. In this case, the mobile robot needs a robust controller that enables the mobile robot to accurately navigate toward the goal. This research tries to address the issues related to self-location of the mobile robot. A robust position recognition system was implemented; the system estimates the position of the mobile robot using a combination of encoder information of the mobile robot and the absolute space coordinate transformation information obtained from external video sources such as a large number of CCTVs installed in the room. Furthermore, vector field histogram method of the pass traveling algorithm of the mobile robot system was applied, and the results of the research were confirmed after conducting experiments.

  14. Study of Robust Position Recognition System of a Mobile Robot Using Multiple Cameras and Absolute Space Coordinates

    International Nuclear Information System (INIS)

    Mo, Se Hyun; Jeon, Young Pil; Park, Jong Ho; Chong, Kil To

    2017-01-01

    With the development of ICT technology, the indoor utilization of robots is increasing. Research on transportation, cleaning, guidance robots, etc., that can be used now or increase the scope of future use will be advanced. To facilitate the use of mobile robots in indoor spaces, the problem of self-location recognition is an important research area to be addressed. If an unexpected collision occurs during the motion of a mobile robot, the position of the mobile robot deviates from the initially planned navigation path. In this case, the mobile robot needs a robust controller that enables the mobile robot to accurately navigate toward the goal. This research tries to address the issues related to self-location of the mobile robot. A robust position recognition system was implemented; the system estimates the position of the mobile robot using a combination of encoder information of the mobile robot and the absolute space coordinate transformation information obtained from external video sources such as a large number of CCTVs installed in the room. Furthermore, vector field histogram method of the pass traveling algorithm of the mobile robot system was applied, and the results of the research were confirmed after conducting experiments.

  15. Robust and unobtrusive algorithm based on position independence for step detection

    Science.gov (United States)

    Qiu, KeCheng; Li, MengYang; Luo, YiHan

    2018-04-01

    Running is becoming one of the most popular exercises among the people, monitoring steps can help users better understand their running process and improve exercise efficiency. In this paper, we design and implement a robust and unobtrusive algorithm based on position independence for step detection under real environment. It applies Butterworth filter to suppress high frequency interference and then employs the projection based on mathematics to transform system to solve the problem of unknown position of smartphone. Finally, using sliding window to suppress the false peak. The algorithm was tested for eight participants on the Android 7.0 platform. In our experiments, the results show that the proposed algorithm can achieve desired effect in spite of device pose.

  16. Robust H∞ Control of Neutral System with Time-Delay for Dynamic Positioning Ships

    Directory of Open Access Journals (Sweden)

    Dawei Zhao

    2015-01-01

    Full Text Available Due to the input time-delay existing in most thrust systems of the ships, the robust H∞ controller is designed for the ship dynamic positioning (DP system with time-delay. The input delay system is turned to a neutral time-delay system by a state-derivative control law. The less conservative result is derived for the neutral system with state-derivative feedback by the delay-decomposition approach and linear matrix inequality (LMI. Finally, the numerical simulations demonstrate the asymptotic stability and robustness of the controller and verify that the designed DP controller is effective in the varying environment disturbances of wind, waves, and ocean currents.

  17. Robust H(∞) positional control of 2-DOF robotic arm driven by electro-hydraulic servo system.

    Science.gov (United States)

    Guo, Qing; Yu, Tian; Jiang, Dan

    2015-11-01

    In this paper an H∞ positional feedback controller is developed to improve the robust performance under structural and parametric uncertainty disturbance in electro-hydraulic servo system (EHSS). The robust control model is described as the linear state-space equation by upper linear fractional transformation. According to the solution of H∞ sub-optimal control problem, the robust controller is designed and simplified to lower order linear model which is easily realized in EHSS. The simulation and experimental results can validate the robustness of this proposed method. The comparison result with PI control shows that the robust controller is suitable for this EHSS under the critical condition where the desired system bandwidth is higher and the external load of the hydraulic actuator is closed to its limited capability. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  18. Robust Solvers for Symmetric Positive Definite Operators and Weighted Poincaré Inequalities

    KAUST Repository

    Efendiev, Yalchin

    2012-01-01

    An abstract setting for robustly preconditioning symmetric positive definite (SPD) operators is presented. The term "robust" refers to the property of the condition numbers of the preconditioned systems being independent of mesh parameters and problem parameters. Important instances of such problem parameters are in particular (highly varying) coefficients. The method belongs to the class of additive Schwarz preconditioners. The paper gives an overview of the results obtained in a recent paper by the authors. It, furthermore, focuses on the importance of weighted Poincaré inequalities, whose notion is extended to general SPD operators, for the analysis of stable decompositions. To demonstrate the applicability of the abstract preconditioner the scalar elliptic equation and the stream function formulation of Brinkman\\'s equations in two spatial dimensions are considered. Several numerical examples are presented. © 2012 Springer-Verlag.

  19. A blind reversible robust watermarking scheme for relational databases.

    Science.gov (United States)

    Chang, Chin-Chen; Nguyen, Thai-Son; Lin, Chia-Chen

    2013-01-01

    Protecting the ownership and controlling the copies of digital data have become very important issues in Internet-based applications. Reversible watermark technology allows the distortion-free recovery of relational databases after the embedded watermark data are detected or verified. In this paper, we propose a new, blind, reversible, robust watermarking scheme that can be used to provide proof of ownership for the owner of a relational database. In the proposed scheme, a reversible data-embedding algorithm, which is referred to as "histogram shifting of adjacent pixel difference" (APD), is used to obtain reversibility. The proposed scheme can detect successfully 100% of the embedded watermark data, even if as much as 80% of the watermarked relational database is altered. Our extensive analysis and experimental results show that the proposed scheme is robust against a variety of data attacks, for example, alteration attacks, deletion attacks, mix-match attacks, and sorting attacks.

  20. A robust rotation-invariance displacement measurement method for a micro-/nano-positioning system

    Science.gov (United States)

    Zhang, Xiang; Zhang, Xianmin; Wu, Heng; Li, Hai; Gan, Jinqiang

    2018-05-01

    A robust and high-precision displacement measurement method for a compliant mechanism-based micro-/nano-positioning system is proposed. The method is composed of an integer-pixel and a sub-pixel matching procedure. In the proposed algorithm (Pro-A), an improved ring projection transform (IRPT) and gradient information are used as features for approximating the coarse candidates and fine locations, respectively. Simulations are conducted and the results show that the Pro-A has the ability of rotation-invariance and strong robustness, with a theoretical accuracy of 0.01 pixel. To validate the practical performance, a series of experiments are carried out using a computer micro-vision and laser interferometer system (LIMS). The results demonstrate that both the LIMS and Pro-A can achieve high precision, while the Pro-A has better stability and adaptability.

  1. Nonlatching positive feedback enables robust bimodality by decoupling expression noise from the mean

    Energy Technology Data Exchange (ETDEWEB)

    Razooky, Brandon S. [Rockefeller Univ., New York, NY (United States). Lab. of Virology and Infectious Disease; Gladstone Institutes (Virology and Immunology), San Francisco, CA (United States); Univ. of California, San Francisco, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Univ. of Tennessee, Knoxville, TN (United States). Bredesen Center for Interdisciplinary; Cao, Youfang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hansen, Maike M. K. [Gladstone Institutes (Virology and Immunology), San Francisco, CA (United States); Perelson, Alan S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Simpson, Michael L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Univ. of Tennessee, Knoxville, TN (United States). Bredesen Center for Interdisciplinary; Weinberger, Leor S. [Gladstone Institutes (Virology and Immunology), San Francisco, CA (United States); Univ. of California, San Francisco, CA (United States). Dept. of Biochemistry and Biophysics; Univ. of California, San Francisco, CA (United States). QB3: California Inst. of Quantitative Biosciences; Univ. of California, San Francisco, CA (United States). Dept. of Pharmaceutical Chemistry

    2017-10-18

    Fundamental to biological decision-making is the ability to generate bimodal expression patterns where two alternate expression states simultaneously exist. Here in this study, we use a combination of single-cell analysis and mathematical modeling to examine the sources of bimodality in the transcriptional program controlling HIV’s fate decision between active replication and viral latency. We find that the HIV Tat protein manipulates the intrinsic toggling of HIV’s promoter, the LTR, to generate bimodal ON-OFF expression, and that transcriptional positive feedback from Tat shifts and expands the regime of LTR bimodality. This result holds for both minimal synthetic viral circuits and full-length virus. Strikingly, computational analysis indicates that the Tat circuit’s non-cooperative ‘non-latching’ feedback architecture is optimized to slow the promoter’s toggling and generate bimodality by stochastic extinction of Tat. In contrast to the standard Poisson model, theory and experiment show that non-latching positive feedback substantially dampens the inverse noise-mean relationship to maintain stochastic bimodality despite increasing mean-expression levels. Given the rapid evolution of HIV, the presence of a circuit optimized to robustly generate bimodal expression appears consistent with the hypothesis that HIV’s decision between active replication and latency provides a viral fitness advantage. More broadly, the results suggest that positive-feedback circuits may have evolved not only for signal amplification but also for robustly generating bimodality by decoupling expression fluctuations (noise) from mean expression levels.

  2. Robust independent modal space control of a coupled nano-positioning piezo-stage

    Science.gov (United States)

    Zhu, Wei; Yang, Fufeng; Rui, Xiaoting

    2018-06-01

    In order to accurately control a coupled 3-DOF nano-positioning piezo-stage, this paper designs a hybrid controller. In this controller, a hysteresis observer based on a Bouc-Wen model is established to compensate the hysteresis nonlinearity of the piezoelectric actuator first. Compared to hysteresis compensations using Preisach model and Prandt-Ishlinskii model, the compensation method using the hysteresis observer is computationally lighter. Then, based on the proposed dynamics model, by constructing the modal filter, a robust H∞ independent modal space controller is designed and utilized to decouple the piezo-stage and deal with the unmodeled dynamics, disturbance, and hysteresis compensation error. The effectiveness of the proposed controller is demonstrated experimentally. The experimental results show that the proposed controller can significantly achieve the high-precision positioning.

  3. Comparison of robustness to outliers between robust poisson models and log-binomial models when estimating relative risks for common binary outcomes: a simulation study.

    Science.gov (United States)

    Chen, Wansu; Shi, Jiaxiao; Qian, Lei; Azen, Stanley P

    2014-06-26

    To estimate relative risks or risk ratios for common binary outcomes, the most popular model-based methods are the robust (also known as modified) Poisson and the log-binomial regression. Of the two methods, it is believed that the log-binomial regression yields more efficient estimators because it is maximum likelihood based, while the robust Poisson model may be less affected by outliers. Evidence to support the robustness of robust Poisson models in comparison with log-binomial models is very limited. In this study a simulation was conducted to evaluate the performance of the two methods in several scenarios where outliers existed. The findings indicate that for data coming from a population where the relationship between the outcome and the covariate was in a simple form (e.g. log-linear), the two models yielded comparable biases and mean square errors. However, if the true relationship contained a higher order term, the robust Poisson models consistently outperformed the log-binomial models even when the level of contamination is low. The robust Poisson models are more robust (or less sensitive) to outliers compared to the log-binomial models when estimating relative risks or risk ratios for common binary outcomes. Users should be aware of the limitations when choosing appropriate models to estimate relative risks or risk ratios.

  4. Robust 3D Position Estimation in Wide and Unconstrained Indoor Environments

    Directory of Open Access Journals (Sweden)

    Annette Mossel

    2015-12-01

    Full Text Available In this paper, a system for 3D position estimation in wide, unconstrained indoor environments is presented that employs infrared optical outside-in tracking of rigid-body targets with a stereo camera rig. To overcome limitations of state-of-the-art optical tracking systems, a pipeline for robust target identification and 3D point reconstruction has been investigated that enables camera calibration and tracking in environments with poor illumination, static and moving ambient light sources, occlusions and harsh conditions, such as fog. For evaluation, the system has been successfully applied in three different wide and unconstrained indoor environments, (1 user tracking for virtual and augmented reality applications, (2 handheld target tracking for tunneling and (3 machine guidance for mining. The results of each use case are discussed to embed the presented approach into a larger technological and application context. The experimental results demonstrate the system’s capabilities to track targets up to 100 m. Comparing the proposed approach to prior art in optical tracking in terms of range coverage and accuracy, it significantly extends the available tracking range, while only requiring two cameras and providing a relative 3D point accuracy with sub-centimeter deviation up to 30 m and low-centimeter deviation up to 100 m.

  5. Robust Correlation Analyses: False Positive and Power Validation Using a New Open Source Matlab Toolbox

    Science.gov (United States)

    Pernet, Cyril R.; Wilcox, Rand; Rousselet, Guillaume A.

    2012-01-01

    Pearson’s correlation measures the strength of the association between two variables. The technique is, however, restricted to linear associations and is overly sensitive to outliers. Indeed, a single outlier can result in a highly inaccurate summary of the data. Yet, it remains the most commonly used measure of association in psychology research. Here we describe a free Matlab(R) based toolbox (http://sourceforge.net/projects/robustcorrtool/) that computes robust measures of association between two or more random variables: the percentage-bend correlation and skipped-correlations. After illustrating how to use the toolbox, we show that robust methods, where outliers are down weighted or removed and accounted for in significance testing, provide better estimates of the true association with accurate false positive control and without loss of power. The different correlation methods were tested with normal data and normal data contaminated with marginal or bivariate outliers. We report estimates of effect size, false positive rate and power, and advise on which technique to use depending on the data at hand. PMID:23335907

  6. Robust correlation analyses: false positive and power validation using a new open source matlab toolbox.

    Science.gov (United States)

    Pernet, Cyril R; Wilcox, Rand; Rousselet, Guillaume A

    2012-01-01

    Pearson's correlation measures the strength of the association between two variables. The technique is, however, restricted to linear associations and is overly sensitive to outliers. Indeed, a single outlier can result in a highly inaccurate summary of the data. Yet, it remains the most commonly used measure of association in psychology research. Here we describe a free Matlab((R)) based toolbox (http://sourceforge.net/projects/robustcorrtool/) that computes robust measures of association between two or more random variables: the percentage-bend correlation and skipped-correlations. After illustrating how to use the toolbox, we show that robust methods, where outliers are down weighted or removed and accounted for in significance testing, provide better estimates of the true association with accurate false positive control and without loss of power. The different correlation methods were tested with normal data and normal data contaminated with marginal or bivariate outliers. We report estimates of effect size, false positive rate and power, and advise on which technique to use depending on the data at hand.

  7. Robust position control of induction motor using fuzzy logic control

    International Nuclear Information System (INIS)

    Kim, Sei Chan; Kim, Duk Hun; Yang, Seung Ho; Won, Chung Yuen

    1993-01-01

    In recent years, fuzzy logic or fuzzy set theory has reveived attention of a number of researchers in the area of power electronics and motion control. The paper describes a vector-controlled induction motor position servo drive where fuzzy control is used to get robustness against parameter variation and load torque disturbance effects. Both coarse and fine control with the help of look-up rule tables are used to improve transient response and system settling time. The performance characteristics are then compared with those of proportional-integral(PI) control. The simulation results clearly indicate the superiority of fuzzy control with larger number of rules. The fuzzy controller was implemented with a 16-bit microprocessor and tested in laboratory on a 3-hp IGBT inverter induction motor drive system. The test results verify the simulation performance. (Author)

  8. Adaptive nonlinear robust relative pose control of spacecraft autonomous rendezvous and proximity operations.

    Science.gov (United States)

    Sun, Liang; Huo, Wei; Jiao, Zongxia

    2017-03-01

    This paper studies relative pose control for a rigid spacecraft with parametric uncertainties approaching to an unknown tumbling target in disturbed space environment. State feedback controllers for relative translation and relative rotation are designed in an adaptive nonlinear robust control framework. The element-wise and norm-wise adaptive laws are utilized to compensate the parametric uncertainties of chaser and target spacecraft, respectively. External disturbances acting on two spacecraft are treated as a lumped and bounded perturbation input for system. To achieve the prescribed disturbance attenuation performance index, feedback gains of controllers are designed by solving linear matrix inequality problems so that lumped disturbance attenuation with respect to the controlled output is ensured in the L 2 -gain sense. Moreover, in the absence of lumped disturbance input, asymptotical convergence of relative pose are proved by using the Lyapunov method. Numerical simulations are performed to show that position tracking and attitude synchronization are accomplished in spite of the presence of couplings and uncertainties. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Robust Hinfinity position control synthesis of an electro-hydraulic servo system.

    Science.gov (United States)

    Milić, Vladimir; Situm, Zeljko; Essert, Mario

    2010-10-01

    This paper focuses on the use of the techniques based on linear matrix inequalities for robust H(infinity) position control synthesis of an electro-hydraulic servo system. A nonlinear dynamic model of the hydraulic cylindrical actuator with a proportional valve has been developed. For the purpose of the feedback control an uncertain linearized mathematical model of the system has been derived. The structured (parametric) perturbations in the electro-hydraulic coefficients are taken into account. H(infinity) controller extended with an integral action is proposed. To estimate internal states of the electro-hydraulic servo system an observer is designed. Developed control algorithms have been tested experimentally in the laboratory model of an electro-hydraulic servo system. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Perceptual Robust Design

    DEFF Research Database (Denmark)

    Pedersen, Søren Nygaard

    The research presented in this PhD thesis has focused on a perceptual approach to robust design. The results of the research and the original contribution to knowledge is a preliminary framework for understanding, positioning, and applying perceptual robust design. Product quality is a topic...... been presented. Therefore, this study set out to contribute to the understanding and application of perceptual robust design. To achieve this, a state-of-the-art and current practice review was performed. From the review two main research problems were identified. Firstly, a lack of tools...... for perceptual robustness was found to overlap with the optimum for functional robustness and at most approximately 2.2% out of the 14.74% could be ascribed solely to the perceptual robustness optimisation. In conclusion, the thesis have offered a new perspective on robust design by merging robust design...

  11. Survey on Ranging Sensors and Cooperative Techniques for Relative Positioning of Vehicles

    Directory of Open Access Journals (Sweden)

    Fabian de Ponte Müller

    2017-01-01

    Full Text Available Future driver assistance systems will rely on accurate, reliable and continuous knowledge on the position of other road participants, including pedestrians, bicycles and other vehicles. The usual approach to tackle this requirement is to use on-board ranging sensors inside the vehicle. Radar, laser scanners or vision-based systems are able to detect objects in their line-of-sight. In contrast to these non-cooperative ranging sensors, cooperative approaches follow a strategy in which other road participants actively support the estimation of the relative position. The limitations of on-board ranging sensors regarding their detection range and angle of view and the facility of blockage can be approached by using a cooperative approach based on vehicle-to-vehicle communication. The fusion of both, cooperative and non-cooperative strategies, seems to offer the largest benefits regarding accuracy, availability and robustness. This survey offers the reader a comprehensive review on different techniques for vehicle relative positioning. The reader will learn the important performance indicators when it comes to relative positioning of vehicles, the different technologies that are both commercially available and currently under research, their expected performance and their intrinsic limitations. Moreover, the latest research in the area of vision-based systems for vehicle detection, as well as the latest work on GNSS-based vehicle localization and vehicular communication for relative positioning of vehicles, are reviewed. The survey also includes the research work on the fusion of cooperative and non-cooperative approaches to increase the reliability and the availability.

  12. Square-Wave Voltage Injection Algorithm for PMSM Position Sensorless Control With High Robustness to Voltage Errors

    DEFF Research Database (Denmark)

    Ni, Ronggang; Xu, Dianguo; Blaabjerg, Frede

    2017-01-01

    relationship with the magnetic field distortion. Position estimation errors caused by higher order harmonic inductances and voltage harmonics generated by the SVPWM are also discussed. Both simulations and experiments are carried out based on a commercial PMSM to verify the superiority of the proposed method......Rotor position estimated with high-frequency (HF) voltage injection methods can be distorted by voltage errors due to inverter nonlinearities, motor resistance, and rotational voltage drops, etc. This paper proposes an improved HF square-wave voltage injection algorithm, which is robust to voltage...... errors without any compensations meanwhile has less fluctuation in the position estimation error. The average position estimation error is investigated based on the analysis of phase harmonic inductances, and deduced in the form of the phase shift of the second-order harmonic inductances to derive its...

  13. Position-Invariant Robust Features for Long-Term Recognition of Dynamic Outdoor Scenes

    Science.gov (United States)

    Kawewong, Aram; Tangruamsub, Sirinart; Hasegawa, Osamu

    A novel Position-Invariant Robust Feature, designated as PIRF, is presented to address the problem of highly dynamic scene recognition. The PIRF is obtained by identifying existing local features (i.e. SIFT) that have a wide baseline visibility within a place (one place contains more than one sequential images). These wide-baseline visible features are then represented as a single PIRF, which is computed as an average of all descriptors associated with the PIRF. Particularly, PIRFs are robust against highly dynamical changes in scene: a single PIRF can be matched correctly against many features from many dynamical images. This paper also describes an approach to using these features for scene recognition. Recognition proceeds by matching an individual PIRF to a set of features from test images, with subsequent majority voting to identify a place with the highest matched PIRF. The PIRF system is trained and tested on 2000+ outdoor omnidirectional images and on COLD datasets. Despite its simplicity, PIRF offers a markedly better rate of recognition for dynamic outdoor scenes (ca. 90%) than the use of other features. Additionally, a robot navigation system based on PIRF (PIRF-Nav) can outperform other incremental topological mapping methods in terms of time (70% less) and memory. The number of PIRFs can be reduced further to reduce the time while retaining high accuracy, which makes it suitable for long-term recognition and localization.

  14. Robust Adaptive Beamforming with Sensor Position Errors Using Weighted Subspace Fitting-Based Covariance Matrix Reconstruction.

    Science.gov (United States)

    Chen, Peng; Yang, Yixin; Wang, Yong; Ma, Yuanliang

    2018-05-08

    When sensor position errors exist, the performance of recently proposed interference-plus-noise covariance matrix (INCM)-based adaptive beamformers may be severely degraded. In this paper, we propose a weighted subspace fitting-based INCM reconstruction algorithm to overcome sensor displacement for linear arrays. By estimating the rough signal directions, we construct a novel possible mismatched steering vector (SV) set. We analyze the proximity of the signal subspace from the sample covariance matrix (SCM) and the space spanned by the possible mismatched SV set. After solving an iterative optimization problem, we reconstruct the INCM using the estimated sensor position errors. Then we estimate the SV of the desired signal by solving an optimization problem with the reconstructed INCM. The main advantage of the proposed algorithm is its robustness against SV mismatches dominated by unknown sensor position errors. Numerical examples show that even if the position errors are up to half of the assumed sensor spacing, the output signal-to-interference-plus-noise ratio is only reduced by 4 dB. Beam patterns plotted using experiment data show that the interference suppression capability of the proposed beamformer outperforms other tested beamformers.

  15. Positive polynomials and robust stabilization with fixed-order controllers

    Czech Academy of Sciences Publication Activity Database

    Henrion, Didier; Šebek, M.; Kučera, V.

    2003-01-01

    Roč. 48, č. 7 (2003), s. 1178-1186 ISSN 0018-9286 R&D Projects: GA ČR GA102/02/0709; GA MŠk ME 496 Institutional research plan: CEZ:AV0Z1075907 Keywords : fixed-order control lers * linear matrix inequality * polynomials, robust control Subject RIV: BC - Control Systems Theory Impact factor: 1.896, year: 2003

  16. Robust Growth Determinants

    OpenAIRE

    Doppelhofer, Gernot; Weeks, Melvyn

    2011-01-01

    This paper investigates the robustness of determinants of economic growth in the presence of model uncertainty, parameter heterogeneity and outliers. The robust model averaging approach introduced in the paper uses a flexible and parsi- monious mixture modeling that allows for fat-tailed errors compared to the normal benchmark case. Applying robust model averaging to growth determinants, the paper finds that eight out of eighteen variables found to be significantly related to economic growth ...

  17. Robustness analysis of interdependent networks under multiple-attacking strategies

    Science.gov (United States)

    Gao, Yan-Li; Chen, Shi-Ming; Nie, Sen; Ma, Fei; Guan, Jun-Jie

    2018-04-01

    The robustness of complex networks under attacks largely depends on the structure of a network and the nature of the attacks. Previous research on interdependent networks has focused on two types of initial attack: random attack and degree-based targeted attack. In this paper, a deliberate attack function is proposed, where six kinds of deliberate attacking strategies can be derived by adjusting the tunable parameters. Moreover, the robustness of four types of interdependent networks (BA-BA, ER-ER, BA-ER and ER-BA) with different coupling modes (random, positive and negative correlation) is evaluated under different attacking strategies. Interesting conclusions could be obtained. It can be found that the positive coupling mode can make the vulnerability of the interdependent network to be absolutely dependent on the most vulnerable sub-network under deliberate attacks, whereas random and negative coupling modes make the vulnerability of interdependent network to be mainly dependent on the being attacked sub-network. The robustness of interdependent network will be enhanced with the degree-degree correlation coefficient varying from positive to negative. Therefore, The negative coupling mode is relatively more optimal than others, which can substantially improve the robustness of the ER-ER network and ER-BA network. In terms of the attacking strategies on interdependent networks, the degree information of node is more valuable than the betweenness. In addition, we found a more efficient attacking strategy for each coupled interdependent network and proposed the corresponding protection strategy for suppressing cascading failure. Our results can be very useful for safety design and protection of interdependent networks.

  18. Robust combined position and formation control for marine surface craft

    DEFF Research Database (Denmark)

    Ihle, Ivar-Andre F.; Jouffroy, Jerome; Fossen, Thor I.

    We consider the robustness properties of a formation control system for marine surface vessels. Intervessel constraint functions are stabilized to achieve the desired formation configuration. We show that the formation dynamics is Input-to-State Stable (ISS) to both environmental perturbations th...

  19. Design principles for robust oscillatory behavior.

    Science.gov (United States)

    Castillo-Hair, Sebastian M; Villota, Elizabeth R; Coronado, Alberto M

    2015-09-01

    Oscillatory responses are ubiquitous in regulatory networks of living organisms, a fact that has led to extensive efforts to study and replicate the circuits involved. However, to date, design principles that underlie the robustness of natural oscillators are not completely known. Here we study a three-component enzymatic network model in order to determine the topological requirements for robust oscillation. First, by simulating every possible topological arrangement and varying their parameter values, we demonstrate that robust oscillators can be obtained by augmenting the number of both negative feedback loops and positive autoregulations while maintaining an appropriate balance of positive and negative interactions. We then identify network motifs, whose presence in more complex topologies is a necessary condition for obtaining oscillatory responses. Finally, we pinpoint a series of simple architectural patterns that progressively render more robust oscillators. Together, these findings can help in the design of more reliable synthetic biomolecular networks and may also have implications in the understanding of other oscillatory systems.

  20. Relative position control design of receiver UAV in flying-boom aerial refueling phase.

    Science.gov (United States)

    An, Shuai; Yuan, Suozhong

    2018-02-01

    This paper proposes the design of the relative position-keeping control of the receiver unmanned aerial vehicle (UAV) with the time-varying mass in the refueling phase utilizing an inner-outer loop structure. Firstly, the model of the receiver in the refueling phase is established. And then tank model is set up to analyze the influence of fuel transfer on the receiver. Subsequently, double power reaching law based sliding mode controller is designed to control receiver translational motion relative to tanker aircraft in the outer loop while active disturbance rejection control technique is applied to the inner loop to stabilize the receiver. In addition, the closed-loop stabilities of the subsystems are established, respectively. Finally, an aerial refueling model under various refueling strategies is utilized. Simulations and comparative analysis demonstrate the effectiveness and robustness of the proposed controllers. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  1. Qualitative Robustness in Estimation

    Directory of Open Access Journals (Sweden)

    Mohammed Nasser

    2012-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Times New Roman","serif";} Qualitative robustness, influence function, and breakdown point are three main concepts to judge an estimator from the viewpoint of robust estimation. It is important as well as interesting to study relation among them. This article attempts to present the concept of qualitative robustness as forwarded by first proponents and its later development. It illustrates intricacies of qualitative robustness and its relation with consistency, and also tries to remove commonly believed misunderstandings about relation between influence function and qualitative robustness citing some examples from literature and providing a new counter-example. At the end it places a useful finite and a simulated version of   qualitative robustness index (QRI. In order to assess the performance of the proposed measures, we have compared fifteen estimators of correlation coefficient using simulated as well as real data sets.

  2. Robustness of Structural Systems

    DEFF Research Database (Denmark)

    Canisius, T.D.G.; Sørensen, John Dalsgaard; Baker, J.W.

    2007-01-01

    The importance of robustness as a property of structural systems has been recognised following several structural failures, such as that at Ronan Point in 1968,where the consequenceswere deemed unacceptable relative to the initiating damage. A variety of research efforts in the past decades have...... attempted to quantify aspects of robustness such as redundancy and identify design principles that can improve robustness. This paper outlines the progress of recent work by the Joint Committee on Structural Safety (JCSS) to develop comprehensive guidance on assessing and providing robustness in structural...... systems. Guidance is provided regarding the assessment of robustness in a framework that considers potential hazards to the system, vulnerability of system components, and failure consequences. Several proposed methods for quantifying robustness are reviewed, and guidelines for robust design...

  3. A Robust High-Accuracy Ultrasound Indoor Positioning System Based on a Wireless Sensor Network.

    Science.gov (United States)

    Qi, Jun; Liu, Guo-Ping

    2017-11-06

    This paper describes the development and implementation of a robust high-accuracy ultrasonic indoor positioning system (UIPS). The UIPS consists of several wireless ultrasonic beacons in the indoor environment. Each of them has a fixed and known position coordinate and can collect all the transmissions from the target node or emit ultrasonic signals. Every wireless sensor network (WSN) node has two communication modules: one is WiFi, that transmits the data to the server, and the other is the radio frequency (RF) module, which is only used for time synchronization between different nodes, with accuracy up to 1 μ s. The distance between the beacon and the target node is calculated by measuring the time-of-flight (TOF) for the ultrasonic signal, and then the position of the target is computed by some distances and the coordinate of the beacons. TOF estimation is the most important technique in the UIPS. A new time domain method to extract the envelope of the ultrasonic signals is presented in order to estimate the TOF. This method, with the envelope detection filter, estimates the value with the sampled values on both sides based on the least squares method (LSM). The simulation results show that the method can achieve envelope detection with a good filtering effect by means of the LSM. The highest precision and variance can reach 0.61 mm and 0.23 mm, respectively, in pseudo-range measurements with UIPS. A maximum location error of 10.2 mm is achieved in the positioning experiments for a moving robot, when UIPS works on the line-of-sight (LOS) signal.

  4. A Robust High-Accuracy Ultrasound Indoor Positioning System Based on a Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Jun Qi

    2017-11-01

    Full Text Available This paper describes the development and implementation of a robust high-accuracy ultrasonic indoor positioning system (UIPS. The UIPS consists of several wireless ultrasonic beacons in the indoor environment. Each of them has a fixed and known position coordinate and can collect all the transmissions from the target node or emit ultrasonic signals. Every wireless sensor network (WSN node has two communication modules: one is WiFi, that transmits the data to the server, and the other is the radio frequency (RF module, which is only used for time synchronization between different nodes, with accuracy up to 1 μs. The distance between the beacon and the target node is calculated by measuring the time-of-flight (TOF for the ultrasonic signal, and then the position of the target is computed by some distances and the coordinate of the beacons. TOF estimation is the most important technique in the UIPS. A new time domain method to extract the envelope of the ultrasonic signals is presented in order to estimate the TOF. This method, with the envelope detection filter, estimates the value with the sampled values on both sides based on the least squares method (LSM. The simulation results show that the method can achieve envelope detection with a good filtering effect by means of the LSM. The highest precision and variance can reach 0.61 mm and 0.23 mm, respectively, in pseudo-range measurements with UIPS. A maximum location error of 10.2 mm is achieved in the positioning experiments for a moving robot, when UIPS works on the line-of-sight (LOS signal.

  5. Robust domain decomposition preconditioners for abstract symmetric positive definite bilinear forms

    KAUST Repository

    Efendiev, Yalchin

    2012-02-22

    An abstract framework for constructing stable decompositions of the spaces corresponding to general symmetric positive definite problems into "local" subspaces and a global "coarse" space is developed. Particular applications of this abstract framework include practically important problems in porous media applications such as: the scalar elliptic (pressure) equation and the stream function formulation of its mixed form, Stokes\\' and Brinkman\\'s equations. The constant in the corresponding abstract energy estimate is shown to be robust with respect to mesh parameters as well as the contrast, which is defined as the ratio of high and low values of the conductivity (or permeability). The derived stable decomposition allows to construct additive overlapping Schwarz iterative methods with condition numbers uniformly bounded with respect to the contrast and mesh parameters. The coarse spaces are obtained by patching together the eigenfunctions corresponding to the smallest eigenvalues of certain local problems. A detailed analysis of the abstract setting is provided. The proposed decomposition builds on a method of Galvis and Efendiev [Multiscale Model. Simul. 8 (2010) 1461-1483] developed for second order scalar elliptic problems with high contrast. Applications to the finite element discretizations of the second order elliptic problem in Galerkin and mixed formulation, the Stokes equations, and Brinkman\\'s problem are presented. A number of numerical experiments for these problems in two spatial dimensions are provided. © EDP Sciences, SMAI, 2012.

  6. Robust Helicopter Stabilization in the Face of Wind Disturbance

    DEFF Research Database (Denmark)

    A. Danapalasingam, Kumeresan; Leth, John-Josef; la Cour-Harbo, Anders

    2010-01-01

    When a helicopter is required to hover with minimum deviations from a desired position without measurements of an affecting persistent wind disturbance, a robustly stabilizing control action is vital. In this paper, the stabilization of the position and translational velocity of a nonlinear...... controller is then designed based on nonlinear adaptive output regulations and robust stabilization of a chain of integrators by a saturated feedback. Simulation results show the effectiveness of the control design in the stabilization of helicopter motion and the built-in robustness of the controller...

  7. Research for robust femtosecond chirped-pulse amplification laser with an identical positive dispersive media as pulse stretcher and compressor

    International Nuclear Information System (INIS)

    Akahane, Yutaka; Ogawa, Kanade; Tsuji, Koichi; Aoyama, Makoto; Yamakawa, Koichi

    2011-01-01

    We have proposed and demonstrated a simple and robust femtosecond optical-parametric chirped-pulse amplification scheme in which an even order dispersion of an idler pulse is compensated by passing through an identical positive dispersive material used for temporal stretching a signal pulse. By compressing the idler pulses having a negatively chirp in this manner, high power sub-100 fs pulses were successfully obtained with only a transparent glass block used for the stretcher and compressor. (author)

  8. Longitudinal Relations among Positivity, Perceived Positive School Climate, and Prosocial Behavior in Colombian Adolescents

    Science.gov (United States)

    Luengo Kanacri, Bernadette P.; Eisenberg, Nancy; Thartori, Eriona; Pastorelli, Concetta; Uribe Tirado, Liliana M.; Gerbino, Maria; Caprara, Gian V.

    2017-01-01

    Bidirectional relations among adolescents' positivity, perceived positive school climate, and prosocial behavior were examined in Colombian youth. Also, the role of a positive school climate in mediating the relation of positivity to prosocial behaviors was tested. Adolescents (N = 151; M[subscript age] of child in Wave 1 = 12.68, SD = 1.06; 58.9%…

  9. Robust adaptive backstepping neural networks control for spacecraft rendezvous and docking with input saturation.

    Science.gov (United States)

    Xia, Kewei; Huo, Wei

    2016-05-01

    This paper presents a robust adaptive neural networks control strategy for spacecraft rendezvous and docking with the coupled position and attitude dynamics under input saturation. Backstepping technique is applied to design a relative attitude controller and a relative position controller, respectively. The dynamics uncertainties are approximated by radial basis function neural networks (RBFNNs). A novel switching controller consists of an adaptive neural networks controller dominating in its active region combined with an extra robust controller to avoid invalidation of the RBFNNs destroying stability of the system outside the neural active region. An auxiliary signal is introduced to compensate the input saturation with anti-windup technique, and a command filter is employed to approximate derivative of the virtual control in the backstepping procedure. Globally uniformly ultimately bounded of the relative states is proved via Lyapunov theory. Simulation example demonstrates effectiveness of the proposed control scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Robust Design Impact Metrics: Measuring the effect of implementing and using Robust Design

    DEFF Research Database (Denmark)

    Ebro, Martin; Olesen, Jesper; Howard, Thomas J.

    2014-01-01

    Measuring the performance of an organisation’s product development process can be challenging due to the limited use of metrics in R&D. An organisation considering whether to use Robust Design as an integrated part of their development process may find it difficult to define whether it is relevant......, and afterwards measure the effect of having implemented it. This publication identifies and evaluates Robust Design-related metrics and finds that 2 metrics are especially useful: 1) Relative amount of R&D Resources spent after Design Verification and 2) Number of ‘change notes’ after Design Verification....... The metrics have been applied in a case company to test the assumptions made during the evaluation. It is concluded that the metrics are useful and relevant, but further work is necessary to make a proper overview and categorisation of different types of robustness related metrics....

  11. Using modern human cortical bone distribution to test the systemic robusticity hypothesis.

    Science.gov (United States)

    Baab, Karen L; Copes, Lynn E; Ward, Devin L; Wells, Nora; Grine, Frederick E

    2018-06-01

    The systemic robusticity hypothesis links the thickness of cortical bone in both the cranium and limb bones. This hypothesis posits that thick cortical bone is in part a systemic response to circulating hormones, such as growth hormone and thyroid hormone, possibly related to physical activity or cold climates. Although this hypothesis has gained popular traction, only rarely has robusticity of the cranium and postcranial skeleton been considered jointly. We acquired computed tomographic scans from associated crania, femora and humeri from single individuals representing 11 populations in Africa and North America (n = 228). Cortical thickness in the parietal, frontal and occipital bones and cortical bone area in limb bone diaphyses were analyzed using correlation, multiple regression and general linear models to test the hypothesis. Absolute thickness values from the crania were not correlated with cortical bone area of the femur or humerus, which is at odds with the systemic robusticity hypothesis. However, measures of cortical bone scaled by total vault thickness and limb cross-sectional area were positively correlated between the cranium and postcranium. When accounting for a range of potential confounding variables, including sex, age and body mass, variation in relative postcranial cortical bone area explained ∼20% of variation in the proportion of cortical cranial bone thickness. While these findings provide limited support for the systemic robusticity hypothesis, cranial cortical thickness did not track climate or physical activity across populations. Thus, some of the variation in cranial cortical bone thickness in modern humans is attributable to systemic effects, but the driving force behind this effect remains obscure. Moreover, neither absolute nor proportional measures of cranial cortical bone thickness are positively correlated with total cranial bone thickness, complicating the extrapolation of these findings to extinct species where only cranial

  12. Robustness Area Technique Developing Guidelines for Power System Restoration

    Directory of Open Access Journals (Sweden)

    Paulo Murinelli Pesoti

    2017-01-01

    Full Text Available This paper proposes a novel energy based technique called the Robustness Area (RA technique that measures power system robustness levels, as a helper for planning Power System Restorations (PSRs. The motivation is on account of the latest blackouts in Brazil, where the local Independent System Operator (ISO encountered difficulties related to circuit disconnections during the restoration. The technique identifies vulnerable and robust buses, pointing out system areas that should be firstly reinforced during PSR, in order to enhance system stability. A Brazilian power system restoration area is used to compare the guidelines adopted by the ISO with a more suitable new plan indicated by the RA tool. Active power and reactive power load margin and standing phase angle show the method efficiency as a result of a well balanced system configuration, enhancing the restoration performance. Time domain simulations for loop closures and severe events also show the positive impact that the proposed tool brings to PSRs.

  13. The Crane Robust Control

    Directory of Open Access Journals (Sweden)

    Marek Hicar

    2004-01-01

    Full Text Available The article is about a control design for complete structure of the crane: crab, bridge and crane uplift.The most important unknown parameters for simulations are burden weight and length of hanging rope. We will use robustcontrol for crab and bridge control to ensure adaptivity for burden weight and rope length. Robust control will be designed for current control of the crab and bridge, necessary is to know the range of unknown parameters. Whole robust will be splitto subintervals and after correct identification of unknown parameters the most suitable robust controllers will be chosen.The most important condition at the crab and bridge motion is avoiding from burden swinging in the final position. Crab and bridge drive is designed by asynchronous motor fed from frequency converter. We will use crane uplift with burden weightobserver in combination for uplift, crab and bridge drive with cooperation of their parameters: burden weight, rope length and crab and bridge position. Controllers are designed by state control method. We will use preferably a disturbance observerwhich will identify burden weight as a disturbance. The system will be working in both modes at empty hook as well asat maximum load: burden uplifting and dropping down.

  14. Neutral evolution of proteins: The superfunnel in sequence space and its relation to mutational robustness

    Science.gov (United States)

    Noirel, Josselin; Simonson, Thomas

    2008-11-01

    Following Kimura's neutral theory of molecular evolution [M. Kimura, The Neutral Theory of Molecular Evolution (Cambridge University Press, Cambridge, 1983) (reprinted in 1986)], it has become common to assume that the vast majority of viable mutations of a gene confer little or no functional advantage. Yet, in silico models of protein evolution have shown that mutational robustness of sequences could be selected for, even in the context of neutral evolution. The evolution of a biological population can be seen as a diffusion on the network of viable sequences. This network is called a "neutral network." Depending on the mutation rate μ and the population size N, the biological population can evolve purely randomly (μN ≪1) or it can evolve in such a way as to select for sequences of higher mutational robustness (μN ≫1). The stringency of the selection depends not only on the product μN but also on the exact topology of the neutral network, the special arrangement of which was named "superfunnel." Even though the relation between mutation rate, population size, and selection was thoroughly investigated, a study of the salient topological features of the superfunnel that could affect the strength of the selection was wanting. This question is addressed in this study. We use two different models of proteins: on lattice and off lattice. We compare neutral networks computed using these models to random networks. From this, we identify two important factors of the topology that determine the stringency of the selection for mutationally robust sequences. First, the presence of highly connected nodes ("hubs") in the network increases the selection for mutationally robust sequences. Second, the stringency of the selection increases when the correlation between a sequence's mutational robustness and its neighbors' increases. The latter finding relates a global characteristic of the neutral network to a local one, which is attainable through experiments or molecular

  15. Robustness Analysis of Timber Truss Structure

    DEFF Research Database (Denmark)

    Rajčić, Vlatka; Čizmar, Dean; Kirkegaard, Poul Henning

    2010-01-01

    The present paper discusses robustness of structures in general and the robustness requirements given in the codes. Robustness of timber structures is also an issues as this is closely related to Working group 3 (Robustness of systems) of the COST E55 project. Finally, an example of a robustness...... evaluation of a widespan timber truss structure is presented. This structure was built few years ago near Zagreb and has a span of 45m. Reliability analysis of the main members and the system is conducted and based on this a robustness analysis is preformed....

  16. Refueling machine with relative positioning capability

    International Nuclear Information System (INIS)

    Challberg, R.C.; Jones, C.R.

    1998-01-01

    A refueling machine is disclosed having relative positioning capability for refueling a nuclear reactor. The refueling machine includes a pair of articulated arms mounted on a refueling bridge. Each arm supports a respective telescoping mast. Each telescoping mast is designed to flex laterally in response to application of a lateral thrust on the end of the mast. A pendant mounted on the end of the mast carries an air-actuated grapple, television cameras, ultrasonic transducers and waterjet thrusters. The ultrasonic transducers are used to detect the gross position of the grapple relative to the bail of a nuclear fuel assembly in the fuel core. The television cameras acquire an image of the bail which is compared to a pre-stored image in computer memory. The pendant can be rotated until the television image and the pre-stored image match within a predetermined tolerance. Similarly, the waterjet thrusters can be used to apply lateral thrust to the end of the flexible mast to place the grapple in a fine position relative to the bail as a function of the discrepancy between the television and pre-stored images. 11 figs

  17. Refueling machine with relative positioning capability

    Science.gov (United States)

    Challberg, R.C.; Jones, C.R.

    1998-12-15

    A refueling machine is disclosed having relative positioning capability for refueling a nuclear reactor. The refueling machine includes a pair of articulated arms mounted on a refueling bridge. Each arm supports a respective telescoping mast. Each telescoping mast is designed to flex laterally in response to application of a lateral thrust on the end of the mast. A pendant mounted on the end of the mast carries an air-actuated grapple, television cameras, ultrasonic transducers and waterjet thrusters. The ultrasonic transducers are used to detect the gross position of the grapple relative to the bail of a nuclear fuel assembly in the fuel core. The television cameras acquire an image of the bail which is compared to a pre-stored image in computer memory. The pendant can be rotated until the television image and the pre-stored image match within a predetermined tolerance. Similarly, the waterjet thrusters can be used to apply lateral thrust to the end of the flexible mast to place the grapple in a fine position relative to the bail as a function of the discrepancy between the television and pre-stored images. 11 figs.

  18. Robustness Analyses of Timber Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard; Hald, Frederik

    2013-01-01

    The robustness of structural systems has obtained a renewed interest arising from a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. In order to minimise the likelihood of such disproportionate structural failures, many mo...... with respect to robustness of timber structures and will discuss the consequences of such robustness issues related to the future development of timber structures.......The robustness of structural systems has obtained a renewed interest arising from a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. In order to minimise the likelihood of such disproportionate structural failures, many...... modern building codes consider the need for the robustness of structures and provide strategies and methods to obtain robustness. Therefore, a structural engineer may take necessary steps to design robust structures that are insensitive to accidental circumstances. The present paper summaries issues...

  19. Variability of centric relation position in TMD patients.

    NARCIS (Netherlands)

    Zonnenberg, A.J.J.; Mulder, J.

    2006-01-01

    Reproducibility of the centric relation position for patients with temporomandibular disorders (TMD) is not documented in the current literature. It was the objective of this study to assess clinical variability of the centric relation position for TMD patients with a muscle-determined technique by

  20. Nonlinear robust hierarchical control for nonlinear uncertain systems

    Directory of Open Access Journals (Sweden)

    Leonessa Alexander

    1999-01-01

    Full Text Available A nonlinear robust control-system design framework predicated on a hierarchical switching controller architecture parameterized over a set of moving nominal system equilibria is developed. Specifically, using equilibria-dependent Lyapunov functions, a hierarchical nonlinear robust control strategy is developed that robustly stabilizes a given nonlinear system over a prescribed range of system uncertainty by robustly stabilizing a collection of nonlinear controlled uncertain subsystems. The robust switching nonlinear controller architecture is designed based on a generalized (lower semicontinuous Lyapunov function obtained by minimizing a potential function over a given switching set induced by the parameterized nominal system equilibria. The proposed framework robustly stabilizes a compact positively invariant set of a given nonlinear uncertain dynamical system with structured parametric uncertainty. Finally, the efficacy of the proposed approach is demonstrated on a jet engine propulsion control problem with uncertain pressure-flow map data.

  1. The theory behind the age-related positivity effect

    Directory of Open Access Journals (Sweden)

    Andrew E Reed

    2012-09-01

    Full Text Available The positivity effect refers to an age-related trend that favors positive over negative stimuli in cognitive processing. Relative to their younger counterparts, older people attend to and remember more positive than negative information. Since the effect was initially identified and the conceptual basis articulated (Mather & Carstensen, 2005 scores of independent replications and related findings have appeared in the literature. Over the same period, a number of investigations have failed to observe age differences in the cognitive processing of emotional material. When findings are considered in theoretical context, a reliable pattern of evidence emerges that helps to refine conceptual tenets. In this article we articulate the operational definition and theoretical foundations of the positivity effect and review the empirical evidence based on studies of visual attention, memory, decision-making, and neural activation. We conclude with a discussion of future research directions with emphasis on the conditions where a focus on positive information may benefit and/or impair cognitive performance in older people.

  2. Detecting measurement-induced relative-position localization

    International Nuclear Information System (INIS)

    Knott, P A; Sindt, J; Dunningham, J A

    2013-01-01

    The theory of decoherence explains how classicality emerges from an underlying quantum reality. An additional interpretation to this has been proposed in which scattering events induce the localization of relative observables (Rau et al 2003 Science 301 1081). An interesting consequence of this process is that it involves the build-up of certain robust entanglements between the observables being localized. To date the weakness of this interpretation has been the lack of a clear experimental signature that allows it to be tested. Here we provide a simple experimentally accessible scheme that enables just that. We also discuss a Bayesian technique that could, in principle, allow experiments to confirm the localization to any desired degree of accuracy and we present precision requirements that are achievable with current experiments. Finally, we extend the scheme from its initial one dimensional proof of principle to the more real world scenario of three dimensional localization. (paper)

  3. The Robustness of High Danish National Happiness

    DEFF Research Database (Denmark)

    Hussain, M. Azhar

    2014-01-01

    Denmark’s top position in various rankings of country happiness is well-documented. This study goes beyond the national average comparisons and investigates whether Denmark’s top position is also found when we disaggregate data in line with social categories often used within the social sciences....... The central measure is the empirical probability that a given population subgroup in Denmark has significantly higher happiness compared to another country’s similar subgroup in a given year. All five rounds of the European Social Survey are used but only the sixteen countries that were surveyed in each...... of the five rounds are included in this study. The results show that Denmark’s position at the top of the happiness scale is also robust when we look at population subgroups, but not in the sense that Denmark dominates all countries for all years. Instead, a modified version of robustness is necessary...

  4. Histomorphometry and cortical robusticity of the adult human femur.

    Science.gov (United States)

    Miszkiewicz, Justyna Jolanta; Mahoney, Patrick

    2018-01-13

    Recent quantitative analyses of human bone microanatomy, as well as theoretical models that propose bone microstructure and gross anatomical associations, have started to reveal insights into biological links that may facilitate remodeling processes. However, relationships between bone size and the underlying cortical bone histology remain largely unexplored. The goal of this study is to determine the extent to which static indicators of bone remodeling and vascularity, measured using histomorphometric techniques, relate to femoral midshaft cortical width and robusticity. Using previously published and new quantitative data from 450 adult human male (n = 233) and female (n = 217) femora, we determine if these aspects of femoral size relate to bone microanatomy. Scaling relationships are explored and interpreted within the context of tissue form and function. Analyses revealed that the area and diameter of Haversian canals and secondary osteons, and densities of secondary osteons and osteocyte lacunae from the sub-periosteal region of the posterior midshaft femur cortex were significantly, but not consistently, associated with femoral size. Cortical width and bone robusticity were correlated with osteocyte lacunae density and scaled with positive allometry. Diameter and area of osteons and Haversian canals decreased as the width of cortex and bone robusticity increased, revealing a negative allometric relationship. These results indicate that microscopic products of cortical bone remodeling and vascularity are linked to femur size. Allometric relationships between more robust human femora with thicker cortical bone and histological products of bone remodeling correspond with principles of bone functional adaptation. Future studies may benefit from exploring scaling relationships between bone histomorphometric data and measurements of bone macrostructure.

  5. Relative position and extent of the nasal and orbital openings in Gorilla, Pan and the human species from the study of their areas and centres of area.

    Science.gov (United States)

    Schmittbuhl, M; Le Minor, J M; Schaaf, A

    1996-01-01

    In order to quantify the relative position and extent of the nasal and orbital openings in hominoid primates, a new methodology based on image analysis was developed and applied to a series of 134 hominoid skulls (52 Gorilla gorilla; 30 Pan troglodytes; 44 Homo sapiens, and, as comparison material, 8 Pongo pygmaeus). The areas and the centres of area of the orbital and nasal openings were determined automatically. The orbitonasal triangle connecting these three centres of area was then constructed. This triangle was used to quantify the elongation of the face. It was most elongated in gorilla, shortest in the human species and intermediate in Pan; the elongation in Pongo was close to that in Gorilla. The proportions of the areas of the orbital and nasal openings in the face were related to the extent of the bony structures of the midface and were thus used to quantify the facial robustness. A robust face was demonstrated in Gorilla, but a gracile face in the human species. Robusticity in Pan was intermediate.

  6. On-orbit real-time robust cooperative target identification in complex background

    Directory of Open Access Journals (Sweden)

    Wen Zhuoman

    2015-10-01

    Full Text Available Cooperative target identification is the prerequisite for the relative position and orientation measurement between the space robot arm and the to-be-arrested object. We propose an on-orbit real-time robust algorithm for cooperative target identification in complex background using the features of circle and lines. It first extracts only the interested edges in the target image using an adaptive threshold and refines them to about single-pixel-width with improved non-maximum suppression. Adapting a novel tracking approach, edge segments changing smoothly in tangential directions are obtained. With a small amount of calculation, large numbers of invalid edges are removed. From the few remained edges, valid circular arcs are extracted and reassembled to obtain circles according to a reliable criterion. Finally, the target is identified if there are certain numbers of straight lines whose relative positions with the circle match the known target pattern. Experiments demonstrate that the proposed algorithm accurately identifies the cooperative target within the range of 0.3–1.5 m under complex background at the speed of 8 frames per second, regardless of lighting condition and target attitude. The proposed algorithm is very suitable for real-time visual measurement of space robot arm because of its robustness and small memory requirement.

  7. Robustness Assessment of Spatial Timber Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning

    2012-01-01

    Robustness of structural systems has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. In order to minimise the likelihood of such disproportionate structural failures many modern buildi...... to robustness of spatial timber structures and will discuss the consequences of such robustness issues related to the future development of timber structures.......Robustness of structural systems has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. In order to minimise the likelihood of such disproportionate structural failures many modern building...... codes consider the need for robustness of structures and provide strategies and methods to obtain robustness. Therefore a structural engineer may take necessary steps to design robust structures that are insensitive to accidental circumstances. The present paper summaries issues with respect...

  8. Robustness Metrics: Consolidating the multiple approaches to quantify Robustness

    DEFF Research Database (Denmark)

    Göhler, Simon Moritz; Eifler, Tobias; Howard, Thomas J.

    2016-01-01

    robustness metrics; 3) Functional expectancy and dispersion robustness metrics; and 4) Probability of conformance robustness metrics. The goal was to give a comprehensive overview of robustness metrics and guidance to scholars and practitioners to understand the different types of robustness metrics...

  9. Robust Ensemble Filtering and Its Relation to Covariance Inflation in the Ensemble Kalman Filter

    KAUST Repository

    Luo, Xiaodong

    2011-12-01

    A robust ensemble filtering scheme based on the H∞ filtering theory is proposed. The optimal H∞ filter is derived by minimizing the supremum (or maximum) of a predefined cost function, a criterion different from the minimum variance used in the Kalman filter. By design, the H∞ filter is more robust than the Kalman filter, in the sense that the estimation error in the H∞ filter in general has a finite growth rate with respect to the uncertainties in assimilation, except for a special case that corresponds to the Kalman filter. The original form of the H∞ filter contains global constraints in time, which may be inconvenient for sequential data assimilation problems. Therefore a variant is introduced that solves some time-local constraints instead, and hence it is called the time-local H∞ filter (TLHF). By analogy to the ensemble Kalman filter (EnKF), the concept of ensemble time-local H∞ filter (EnTLHF) is also proposed. The general form of the EnTLHF is outlined, and some of its special cases are discussed. In particular, it is shown that an EnKF with certain covariance inflation is essentially an EnTLHF. In this sense, the EnTLHF provides a general framework for conducting covariance inflation in the EnKF-based methods. Some numerical examples are used to assess the relative robustness of the TLHF–EnTLHF in comparison with the corresponding KF–EnKF method.

  10. Robust haptic large distance telemanipulation for ITER

    International Nuclear Information System (INIS)

    Heck, D.J.F.; Heemskerk, C.J.M.; Koning, J.F.; Abbasi, A.; Nijmeijer, H.

    2013-01-01

    Highlights: • ITER remote handling maintenance can be controlled safely over a large distance. • Bilateral teleoperation experiments were performed in a local network. • Wave variables make the controller robust against constant communication delays. • Master and slave position synchronization guaranteed by proportional action. -- Abstract: During shutdowns, maintenance crews are expected to work in 24/6 shifts to perform critical remote handling maintenance tasks on the ITER system. In this article, we investigate the possibility to safely perform these haptic maintenance tasks remotely from control stations located anywhere around the world. To guarantee stability in time delayed bilateral teleoperation, the symmetric position tracking controller using wave variables is selected. This algorithm guarantees robustness against communication delays, can eliminate wave reflections and provide position synchronization of the master and slave devices. Experiments have been conducted under realistic local network bandwidth, latency and jitter constraints. They show sufficient transparency even for substantial communication delays

  11. Robust haptic large distance telemanipulation for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Heck, D.J.F., E-mail: d.j.f.heck@tue.nl [Eindhoven University of Technology, Department of Mechanical Engineering, Eindhoven (Netherlands); Heemskerk, C.J.M.; Koning, J.F. [Heemskerk Innovative Technologies, Sassenheim (Netherlands); Abbasi, A.; Nijmeijer, H. [Eindhoven University of Technology, Department of Mechanical Engineering, Eindhoven (Netherlands)

    2013-10-15

    Highlights: • ITER remote handling maintenance can be controlled safely over a large distance. • Bilateral teleoperation experiments were performed in a local network. • Wave variables make the controller robust against constant communication delays. • Master and slave position synchronization guaranteed by proportional action. -- Abstract: During shutdowns, maintenance crews are expected to work in 24/6 shifts to perform critical remote handling maintenance tasks on the ITER system. In this article, we investigate the possibility to safely perform these haptic maintenance tasks remotely from control stations located anywhere around the world. To guarantee stability in time delayed bilateral teleoperation, the symmetric position tracking controller using wave variables is selected. This algorithm guarantees robustness against communication delays, can eliminate wave reflections and provide position synchronization of the master and slave devices. Experiments have been conducted under realistic local network bandwidth, latency and jitter constraints. They show sufficient transparency even for substantial communication delays.

  12. A robust neural network-based approach for microseismic event detection

    KAUST Repository

    Akram, Jubran

    2017-08-17

    We present an artificial neural network based approach for robust event detection from low S/N waveforms. We use a feed-forward network with a single hidden layer that is tuned on a training dataset and later applied on the entire example dataset for event detection. The input features used include the average of absolute amplitudes, variance, energy-ratio and polarization rectilinearity. These features are calculated in a moving-window of same length for the entire waveform. The output is set as a user-specified relative probability curve, which provides a robust way of distinguishing between weak and strong events. An optimal network is selected by studying the weight-based saliency and effect of number of neurons on the predicted results. Using synthetic data examples, we demonstrate that this approach is effective in detecting weaker events and reduces the number of false positives.

  13. Robust Kernel (Cross-) Covariance Operators in Reproducing Kernel Hilbert Space toward Kernel Methods

    OpenAIRE

    Alam, Md. Ashad; Fukumizu, Kenji; Wang, Yu-Ping

    2016-01-01

    To the best of our knowledge, there are no general well-founded robust methods for statistical unsupervised learning. Most of the unsupervised methods explicitly or implicitly depend on the kernel covariance operator (kernel CO) or kernel cross-covariance operator (kernel CCO). They are sensitive to contaminated data, even when using bounded positive definite kernels. First, we propose robust kernel covariance operator (robust kernel CO) and robust kernel crosscovariance operator (robust kern...

  14. LGBTQ relationally based positive psychology: An inclusive and systemic framework.

    Science.gov (United States)

    Domínguez, Daniela G; Bobele, Monte; Coppock, Jacqueline; Peña, Ezequiel

    2015-05-01

    Positive psychologists have contributed to our understandings of how positive emotions and flexible cognition enhance resiliency. However, positive psychologists' research has been slow to address the relational resources and interactions that help nonheterosexual families overcome adversity. Addressing overlooked lesbian, gay, bisexual, transgender, or queer (LGBTQ) and systemic factors in positive psychology, this article draws on family resilience literature and LGBTQ literature to theorize a systemic positive psychology framework for working with nonheterosexual families. We developed the LGBTQ relationally based positive psychology framework that integrates positive psychology's strengths-based perspective with the systemic orientation of Walsh's (1996) family resilience framework along with the cultural considerations proposed by LGBTQ family literature. We theorize that the LGBTQ relationally based positive psychology framework takes into consideration the sociopolitical adversities impacting nonheterosexual families and sensitizes positive psychologists, including those working in organized care settings, to the systemic interactions of same-sex loving relationships. (c) 2015 APA, all rights reserved).

  15. Identification and robust control of an experimental servo motor.

    Science.gov (United States)

    Adam, E J; Guestrin, E D

    2002-04-01

    In this work, the design of a robust controller for an experimental laboratory-scale position control system based on a dc motor drive as well as the corresponding identification and robust stability analysis are presented. In order to carry out the robust design procedure, first, a classic closed-loop identification technique is applied and then, the parametrization by internal model control is used. The model uncertainty is evaluated under both parametric and global representation. For the latter case, an interesting discussion about the conservativeness of this description is presented by means of a comparison between the uncertainty disk and the critical perturbation radius approaches. Finally, conclusions about the performance of the experimental system with the robust controller are discussed using comparative graphics of the controlled variable and the Nyquist stability margin as a robustness measurement.

  16. Multivariable robust control of an air-handling unit: A comparison between pole-placement and H∞ controllers

    International Nuclear Information System (INIS)

    Moradi, Hamed; Bakhtiari-Nejad, Firooz; Saffar-Avval, Majid

    2012-01-01

    Highlights: ► Robust control of a multivariable air-handling unit (AHU). ► Controllers designed based on pole-placement and μ-synthesis. ► Robust performance in the presence of model uncertainties. ► Achievement of various tracking objectives in temperature and relative humidity. ► Comfort conditions in buildings with low energy consumption and operation cost. - Abstract: Control of air-conditioner units is essential to achieve satisfactory comfort conditions in buildings while keeping low energy consumption and operation costs. In this paper, a nonlinear multiinput and multioutput model (MIMO) of an air-handling unit (AHU) is considered. After linearization of the state equations around the operating points, an observer and a regulator are designed for the estimation of state variables and disturbance rejection, respectively. A realistic uncertain model is considered which constitutes various uncertainties associated with complex nonlinear model of AHU. In the presence of model uncertainties, a H ∞ -robust controller is designed to guarantee robust performance of the air-handling unit. In addition, a simple controller based on pole-placement approach is developed. Indoor temperature and relative humidity are controlled via manipulation of valve positions of air and cold water flow rates. Achievement of tracking objectives is investigated through various desired commands of indoor temperature and relative humidity (including a sequence of steps and ramps-steps). According to results, the H ∞ -robust controller guarantees the robust performance of the AHU in tracking of desired set-paths (while using the simple pole-placement controller leads to high oscillatory behavior of the output variables and control efforts). Moreover, using H ∞ -robust controller results in less energy consumption in comparison with the pole-placement controller.

  17. Relational interaction in occupational therapy: Conversation analysis of positive feedback.

    Science.gov (United States)

    Weiste, Elina

    2018-01-01

    The therapeutic relationship is an important factor for good therapy outcomes. The primary mediator of a beneficial therapy relationship is clinician-client interaction. However, few studies identify the observable interactional attributes of good quality relational interactions, e.g. offering the client positive feedback. The present paper aims to expand current understanding of relational interaction by analyzing the real-time interactional practices therapists use for offering positive feedback, an important value in occupational therapy. The analysis is based on the conversation analysis of 15 video-recorded occupational therapy encounters in psychiatric outpatient clinics. Two types of positive feedback were identified. In aligning feedback, therapists encouraged and complimented clients' positive perspectives on their own achievements in adopting certain behaviour, encouraging and supporting their progress. In redirecting feedback, therapists shifted the perspective from clients' negative experiences to their positive experiences. This shift was interactionally successful if they laid the foundation for the shift in perspective and attuned their expressions to the clients' emotional states. Occupational therapists routinely provide their clients with positive feedback. Awareness of the interactional attributes related to positive feedback is critically important for successful relational interaction.

  18. Robustness of quantum correlations against linear noise

    International Nuclear Information System (INIS)

    Guo, Zhihua; Cao, Huaixin; Qu, Shixian

    2016-01-01

    Relative robustness of quantum correlations (RRoQC) of a bipartite state is firstly introduced relative to a classically correlated state. Robustness of quantum correlations (RoQC) of a bipartite state is then defined as the minimum of RRoQC of the state relative to all classically correlated ones. It is proved that as a function on quantum states, RoQC is nonnegative, lower semi-continuous and neither convex nor concave; especially, it is zero if and only if the state is classically correlated. Thus, RoQC not only quantifies the endurance of quantum correlations of a state against linear noise, but also can be used to distinguish between quantum and classically correlated states. Furthermore, the effects of local quantum channels on the robustness are explored and characterized. (paper)

  19. Robustness from flexibility in the fungal circadian clock

    Directory of Open Access Journals (Sweden)

    Akman Ozgur E

    2010-06-01

    Full Text Available Abstract Background Robustness is a central property of living systems, enabling function to be maintained against environmental perturbations. A key challenge is to identify the structures in biological circuits that confer system-level properties such as robustness. Circadian clocks allow organisms to adapt to the predictable changes of the 24-hour day/night cycle by generating endogenous rhythms that can be entrained to the external cycle. In all organisms, the clock circuits typically comprise multiple interlocked feedback loops controlling the rhythmic expression of key genes. Previously, we showed that such architectures increase the flexibility of the clock's rhythmic behaviour. We now test the relationship between flexibility and robustness, using a mathematical model of the circuit controlling conidiation in the fungus Neurospora crassa. Results The circuit modelled in this work consists of a central negative feedback loop, in which the frequency (frq gene inhibits its transcriptional activator white collar-1 (wc-1, interlocked with a positive feedback loop in which FRQ protein upregulates WC-1 production. Importantly, our model reproduces the observed entrainment of this circuit under light/dark cycles with varying photoperiod and cycle duration. Our simulations show that whilst the level of frq mRNA is driven directly by the light input, the falling phase of FRQ protein, a molecular correlate of conidiation, maintains a constant phase that is uncoupled from the times of dawn and dusk. The model predicts the behaviour of mutants that uncouple WC-1 production from FRQ's positive feedback, and shows that the positive loop enhances the buffering of conidiation phase against seasonal photoperiod changes. This property is quantified using Kitano's measure for the overall robustness of a regulated system output. Further analysis demonstrates that this functional robustness is a consequence of the greater evolutionary flexibility conferred on

  20. Efficacy of robust optimization plan with partial-arc VMAT for photon volumetric-modulated arc therapy: A phantom study.

    Science.gov (United States)

    Miura, Hideharu; Ozawa, Shuichi; Nagata, Yasushi

    2017-09-01

    This study investigated position dependence in planning target volume (PTV)-based and robust optimization plans using full-arc and partial-arc volumetric modulated arc therapy (VMAT). The gantry angles at the periphery, intermediate, and center CTV positions were 181°-180° (full-arc VMAT) and 181°-360° (partial-arc VMAT). A PTV-based optimization plan was defined by 5 mm margin expansion of the CTV to a PTV volume, on which the dose constraints were applied. The robust optimization plan consisted of a directly optimized dose to the CTV under a maximum-uncertainties setup of 5 mm. The prescription dose was normalized to the CTV D 99% (the minimum relative dose that covers 99% of the volume of the CTV) as an original plan. The isocenter was rigidly shifted at 1 mm intervals in the anterior-posterior (A-P), superior-inferior (S-I), and right-left (R-L) directions from the original position to the maximum-uncertainties setup of 5 mm in the original plan, yielding recalculated dose distributions. It was found that for the intermediate and center positions, the uncertainties in the D 99% doses to the CTV for all directions did not significantly differ when comparing the PTV-based and robust optimization plans (P > 0.05). For the periphery position, uncertainties in the D 99% doses to the CTV in the R-L direction for the robust optimization plan were found to be lower than those in the PTV-based optimization plan (P plan's efficacy using partial-arc VMAT depends on the periphery CTV position. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  1. On the relation between flexibility analysis and robust optimization for linear systems

    KAUST Repository

    Zhang, Qi

    2016-03-05

    Flexibility analysis and robust optimization are two approaches to solving optimization problems under uncertainty that share some fundamental concepts, such as the use of polyhedral uncertainty sets and the worst-case approach to guarantee feasibility. The connection between these two approaches has not been sufficiently acknowledged and examined in the literature. In this context, the contributions of this work are fourfold: (1) a comparison between flexibility analysis and robust optimization from a historical perspective is presented; (2) for linear systems, new formulations for the three classical flexibility analysis problems—flexibility test, flexibility index, and design under uncertainty—based on duality theory and the affinely adjustable robust optimization (AARO) approach are proposed; (3) the AARO approach is shown to be generally more restrictive such that it may lead to overly conservative solutions; (4) numerical examples show the improved computational performance from the proposed formulations compared to the traditional flexibility analysis models. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3109–3123, 2016

  2. Robust hopping based on virtual pendulum posture control

    International Nuclear Information System (INIS)

    Sharbafi, Maziar A; Ahmadabadi, Majid Nili; Yazdanpanah, Mohammad J; Maufroy, Christophe; Seyfarth, Andre

    2013-01-01

    A new control approach to achieve robust hopping against perturbations in the sagittal plane is presented in this paper. In perturbed hopping, vertical body alignment has a significant role for stability. Our approach is based on the virtual pendulum concept, recently proposed, based on experimental findings in human and animal locomotion. In this concept, the ground reaction forces are pointed to a virtual support point, named virtual pivot point (VPP), during motion. This concept is employed in designing the controller to balance the trunk during the stance phase. New strategies for leg angle and length adjustment besides the virtual pendulum posture control are proposed as a unified controller. This method is investigated by applying it on an extension of the spring loaded inverted pendulum (SLIP) model. Trunk, leg mass and damping are added to the SLIP model in order to make the model more realistic. The stability is analyzed by Poincaré map analysis. With fixed VPP position, stability, disturbance rejection and moderate robustness are achieved, but with a low convergence speed. To improve the performance and attain higher robustness, an event-based control of the VPP position is introduced, using feedback of the system states at apexes. Discrete linear quartic regulator is used to design the feedback controller. Considerable enhancements with respect to stability, convergence speed and robustness against perturbations and parameter changes are achieved. (paper)

  3. Robust design optimization using the price of robustness, robust least squares and regularization methods

    Science.gov (United States)

    Bukhari, Hassan J.

    2017-12-01

    In this paper a framework for robust optimization of mechanical design problems and process systems that have parametric uncertainty is presented using three different approaches. Robust optimization problems are formulated so that the optimal solution is robust which means it is minimally sensitive to any perturbations in parameters. The first method uses the price of robustness approach which assumes the uncertain parameters to be symmetric and bounded. The robustness for the design can be controlled by limiting the parameters that can perturb.The second method uses the robust least squares method to determine the optimal parameters when data itself is subjected to perturbations instead of the parameters. The last method manages uncertainty by restricting the perturbation on parameters to improve sensitivity similar to Tikhonov regularization. The methods are implemented on two sets of problems; one linear and the other non-linear. This methodology will be compared with a prior method using multiple Monte Carlo simulation runs which shows that the approach being presented in this paper results in better performance.

  4. Robust Steganography Using LSB-XOR and Image Sharing

    OpenAIRE

    Adak, Chandranath

    2013-01-01

    Hiding and securing the secret digital information and data that are transmitted over the internet is of widespread and most challenging interest. This paper presents a new idea of robust steganography using bitwise-XOR operation between stego-key-image-pixel LSB (Least Significant Bit) value and secret message-character ASCII-binary value (or, secret image-pixel value). The stego-key-image is shared in dual-layer using odd-even position of each pixel to make the system robust. Due to image s...

  5. Robust control design with MATLAB

    CERN Document Server

    Gu, Da-Wei; Konstantinov, Mihail M

    2013-01-01

    Robust Control Design with MATLAB® (second edition) helps the student to learn how to use well-developed advanced robust control design methods in practical cases. To this end, several realistic control design examples from teaching-laboratory experiments, such as a two-wheeled, self-balancing robot, to complex systems like a flexible-link manipulator are given detailed presentation. All of these exercises are conducted using MATLAB® Robust Control Toolbox 3, Control System Toolbox and Simulink®. By sharing their experiences in industrial cases with minimum recourse to complicated theories and formulae, the authors convey essential ideas and useful insights into robust industrial control systems design using major H-infinity optimization and related methods allowing readers quickly to move on with their own challenges. The hands-on tutorial style of this text rests on an abundance of examples and features for the second edition: ·        rewritten and simplified presentation of theoretical and meth...

  6. Robust Portfolio Optimization Using Pseudodistances

    Science.gov (United States)

    2015-01-01

    The presence of outliers in financial asset returns is a frequently occurring phenomenon which may lead to unreliable mean-variance optimized portfolios. This fact is due to the unbounded influence that outliers can have on the mean returns and covariance estimators that are inputs in the optimization procedure. In this paper we present robust estimators of mean and covariance matrix obtained by minimizing an empirical version of a pseudodistance between the assumed model and the true model underlying the data. We prove and discuss theoretical properties of these estimators, such as affine equivariance, B-robustness, asymptotic normality and asymptotic relative efficiency. These estimators can be easily used in place of the classical estimators, thereby providing robust optimized portfolios. A Monte Carlo simulation study and applications to real data show the advantages of the proposed approach. We study both in-sample and out-of-sample performance of the proposed robust portfolios comparing them with some other portfolios known in literature. PMID:26468948

  7. Robust Portfolio Optimization Using Pseudodistances.

    Science.gov (United States)

    Toma, Aida; Leoni-Aubin, Samuela

    2015-01-01

    The presence of outliers in financial asset returns is a frequently occurring phenomenon which may lead to unreliable mean-variance optimized portfolios. This fact is due to the unbounded influence that outliers can have on the mean returns and covariance estimators that are inputs in the optimization procedure. In this paper we present robust estimators of mean and covariance matrix obtained by minimizing an empirical version of a pseudodistance between the assumed model and the true model underlying the data. We prove and discuss theoretical properties of these estimators, such as affine equivariance, B-robustness, asymptotic normality and asymptotic relative efficiency. These estimators can be easily used in place of the classical estimators, thereby providing robust optimized portfolios. A Monte Carlo simulation study and applications to real data show the advantages of the proposed approach. We study both in-sample and out-of-sample performance of the proposed robust portfolios comparing them with some other portfolios known in literature.

  8. International Conference on Robust Statistics 2015

    CERN Document Server

    Basu, Ayanendranath; Filzmoser, Peter; Mukherjee, Diganta

    2016-01-01

    This book offers a collection of recent contributions and emerging ideas in the areas of robust statistics presented at the International Conference on Robust Statistics 2015 (ICORS 2015) held in Kolkata during 12–16 January, 2015. The book explores the applicability of robust methods in other non-traditional areas which includes the use of new techniques such as skew and mixture of skew distributions, scaled Bregman divergences, and multilevel functional data methods; application areas being circular data models and prediction of mortality and life expectancy. The contributions are of both theoretical as well as applied in nature. Robust statistics is a relatively young branch of statistical sciences that is rapidly emerging as the bedrock of statistical analysis in the 21st century due to its flexible nature and wide scope. Robust statistics supports the application of parametric and other inference techniques over a broader domain than the strictly interpreted model scenarios employed in classical statis...

  9. Robust Position Tracking for Electro-Hydraulic Drives Based on Generalized Feedforward Compensation Approach

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Andersen, Torben Ole; Pedersen, Henrik C.

    2012-01-01

    This paper presents a robust tracking control concept based on accurate feedforward compensation for hydraulic valve-cylinder drives. The proposed feedforward compensator is obtained utilizing a generalized description of the valve flow that takes into account any asymmetry of valves and...... constant gain type feedforward compensator, when subjected to strong perturbations in supply pressure and coulomb friction....

  10. Robustness of Long Span Reciprocal Timber Structures

    DEFF Research Database (Denmark)

    Balfroid, Nathalie; Kirkegaard, Poul Henning

    2011-01-01

    engineer may take necessary steps to design robust structures that are insensitive to accidental circumstances. The present paper makes a discussion of such robustness issues related to the future development of reciprocal timber structures. The paper concludes that these kind of structures can have...... a potential as long span timber structures in real projects if they are carefully designed with respect to the overall robustness strategies.......Robustness of structural systems has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. The interest has also been facilitated due to recently severe structural failures...

  11. Robust and Accurate Image-Based Georeferencing Exploiting Relative Orientation Constraints

    Science.gov (United States)

    Cavegn, S.; Blaser, S.; Nebiker, S.; Haala, N.

    2018-05-01

    Urban environments with extended areas of poor GNSS coverage as well as indoor spaces that often rely on real-time SLAM algorithms for camera pose estimation require sophisticated georeferencing in order to fulfill our high requirements of a few centimeters for absolute 3D point measurement accuracies. Since we focus on image-based mobile mapping, we extended the structure-from-motion pipeline COLMAP with georeferencing capabilities by integrating exterior orientation parameters from direct sensor orientation or SLAM as well as ground control points into bundle adjustment. Furthermore, we exploit constraints for relative orientation parameters among all cameras in bundle adjustment, which leads to a significant robustness and accuracy increase especially by incorporating highly redundant multi-view image sequences. We evaluated our integrated georeferencing approach on two data sets, one captured outdoors by a vehicle-based multi-stereo mobile mapping system and the other captured indoors by a portable panoramic mobile mapping system. We obtained mean RMSE values for check point residuals between image-based georeferencing and tachymetry of 2 cm in an indoor area, and 3 cm in an urban environment where the measurement distances are a multiple compared to indoors. Moreover, in comparison to a solely image-based procedure, our integrated georeferencing approach showed a consistent accuracy increase by a factor of 2-3 at our outdoor test site. Due to pre-calibrated relative orientation parameters, images of all camera heads were oriented correctly in our challenging indoor environment. By performing self-calibration of relative orientation parameters among respective cameras of our vehicle-based mobile mapping system, remaining inaccuracies from suboptimal test field calibration were successfully compensated.

  12. ROBUST AND ACCURATE IMAGE-BASED GEOREFERENCING EXPLOITING RELATIVE ORIENTATION CONSTRAINTS

    Directory of Open Access Journals (Sweden)

    S. Cavegn

    2018-05-01

    Full Text Available Urban environments with extended areas of poor GNSS coverage as well as indoor spaces that often rely on real-time SLAM algorithms for camera pose estimation require sophisticated georeferencing in order to fulfill our high requirements of a few centimeters for absolute 3D point measurement accuracies. Since we focus on image-based mobile mapping, we extended the structure-from-motion pipeline COLMAP with georeferencing capabilities by integrating exterior orientation parameters from direct sensor orientation or SLAM as well as ground control points into bundle adjustment. Furthermore, we exploit constraints for relative orientation parameters among all cameras in bundle adjustment, which leads to a significant robustness and accuracy increase especially by incorporating highly redundant multi-view image sequences. We evaluated our integrated georeferencing approach on two data sets, one captured outdoors by a vehicle-based multi-stereo mobile mapping system and the other captured indoors by a portable panoramic mobile mapping system. We obtained mean RMSE values for check point residuals between image-based georeferencing and tachymetry of 2 cm in an indoor area, and 3 cm in an urban environment where the measurement distances are a multiple compared to indoors. Moreover, in comparison to a solely image-based procedure, our integrated georeferencing approach showed a consistent accuracy increase by a factor of 2–3 at our outdoor test site. Due to pre-calibrated relative orientation parameters, images of all camera heads were oriented correctly in our challenging indoor environment. By performing self-calibration of relative orientation parameters among respective cameras of our vehicle-based mobile mapping system, remaining inaccuracies from suboptimal test field calibration were successfully compensated.

  13. Integrating positive psychology into health-related quality of life research.

    Science.gov (United States)

    Park, Crystal L

    2015-07-01

    Positive psychology is an increasingly influential force in theory and research within psychology and many related fields, including behavioral medicine, sociology, and public health. This article aims to review the ways in which positive psychology and health-related quality of life (HRQOL) research currently interface and to suggest fruitful future directions. This article reviews the basic elements of positive psychology and provides an overview of conceptual and empirical links between positive psychology and HRQOL. The role of one central aspect of positive psychology (meaning) within HRQOL is highlighted, and unresolved issues (e.g., lack of definitional clarity) are discussed. Some research on HRQOL has taken a positive psychology perspective, demonstrating the usefulness of taking a positive psychology approach. However, many areas await integration. Once conceptual and methodological issues are resolved, positive psychology may profitably inform many aspects of HRQOL research and, perhaps, clinical interventions to promote HRQOL as well.

  14. Indirect two-sided relative ranking: a robust similarity measure for gene expression data

    Directory of Open Access Journals (Sweden)

    Licamele Louis

    2010-03-01

    Full Text Available Abstract Background There is a large amount of gene expression data that exists in the public domain. This data has been generated under a variety of experimental conditions. Unfortunately, these experimental variations have generally prevented researchers from accurately comparing and combining this wealth of data, which still hides many novel insights. Results In this paper we present a new method, which we refer to as indirect two-sided relative ranking, for comparing gene expression profiles that is robust to variations in experimental conditions. This method extends the current best approach, which is based on comparing the correlations of the up and down regulated genes, by introducing a comparison based on the correlations in rankings across the entire database. Because our method is robust to experimental variations, it allows a greater variety of gene expression data to be combined, which, as we show, leads to richer scientific discoveries. Conclusions We demonstrate the benefit of our proposed indirect method on several datasets. We first evaluate the ability of the indirect method to retrieve compounds with similar therapeutic effects across known experimental barriers, namely vehicle and batch effects, on two independent datasets (one private and one public. We show that our indirect method is able to significantly improve upon the previous state-of-the-art method with a substantial improvement in recall at rank 10 of 97.03% and 49.44%, on each dataset, respectively. Next, we demonstrate that our indirect method results in improved accuracy for classification in several additional datasets. These datasets demonstrate the use of our indirect method for classifying cancer subtypes, predicting drug sensitivity/resistance, and classifying (related cell types. Even in the absence of a known (i.e., labeled experimental barrier, the improvement of the indirect method in each of these datasets is statistically significant.

  15. Degeneracy: a link between evolvability, robustness and complexity in biological systems

    Directory of Open Access Journals (Sweden)

    Whitacre James M

    2010-02-01

    Full Text Available Abstract A full accounting of biological robustness remains elusive; both in terms of the mechanisms by which robustness is achieved and the forces that have caused robustness to grow over evolutionary time. Although its importance to topics such as ecosystem services and resilience is well recognized, the broader relationship between robustness and evolution is only starting to be fully appreciated. A renewed interest in this relationship has been prompted by evidence that mutational robustness can play a positive role in the discovery of adaptive innovations (evolvability and evidence of an intimate relationship between robustness and complexity in biology. This paper offers a new perspective on the mechanics of evolution and the origins of complexity, robustness, and evolvability. Here we explore the hypothesis that degeneracy, a partial overlap in the functioning of multi-functional components, plays a central role in the evolution and robustness of complex forms. In support of this hypothesis, we present evidence that degeneracy is a fundamental source of robustness, it is intimately tied to multi-scaled complexity, and it establishes conditions that are necessary for system evolvability.

  16. A Unifying Mathematical Framework for Genetic Robustness, Environmental Robustness, Network Robustness and their Trade-offs on Phenotype Robustness in Biological Networks. Part III: Synthetic Gene Networks in Synthetic Biology

    Science.gov (United States)

    Chen, Bor-Sen; Lin, Ying-Po

    2013-01-01

    Robust stabilization and environmental disturbance attenuation are ubiquitous systematic properties that are observed in biological systems at many different levels. The underlying principles for robust stabilization and environmental disturbance attenuation are universal to both complex biological systems and sophisticated engineering systems. In many biological networks, network robustness should be large enough to confer: intrinsic robustness for tolerating intrinsic parameter fluctuations; genetic robustness for buffering genetic variations; and environmental robustness for resisting environmental disturbances. Network robustness is needed so phenotype stability of biological network can be maintained, guaranteeing phenotype robustness. Synthetic biology is foreseen to have important applications in biotechnology and medicine; it is expected to contribute significantly to a better understanding of functioning of complex biological systems. This paper presents a unifying mathematical framework for investigating the principles of both robust stabilization and environmental disturbance attenuation for synthetic gene networks in synthetic biology. Further, from the unifying mathematical framework, we found that the phenotype robustness criterion for synthetic gene networks is the following: if intrinsic robustness + genetic robustness + environmental robustness ≦ network robustness, then the phenotype robustness can be maintained in spite of intrinsic parameter fluctuations, genetic variations, and environmental disturbances. Therefore, the trade-offs between intrinsic robustness, genetic robustness, environmental robustness, and network robustness in synthetic biology can also be investigated through corresponding phenotype robustness criteria from the systematic point of view. Finally, a robust synthetic design that involves network evolution algorithms with desired behavior under intrinsic parameter fluctuations, genetic variations, and environmental

  17. Robust balance shift control with posture optimization

    NARCIS (Netherlands)

    Kavafoglu, Z.; Kavafoglu, Ersan; Egges, J.

    2015-01-01

    In this paper we present a control framework which creates robust and natural balance shifting behaviours during standing. Given high-level features such as the position of the center of mass projection and the foot configurations, a kinematic posture satisfying these features is synthesized using

  18. Application of the robust design concept for fuel loading pattern

    International Nuclear Information System (INIS)

    Endo, Tomohiro; Ohori, Kazuma; Yamamoto, Akio

    2011-01-01

    Application of the robust design concept for fuel loading pattern design is proposed as a new approach to improve the prediction accuracy of core characteristics. The robust design is a design concept that establishes a resistant (robust) system for perturbations or noises, by properly setting design variables. In order to apply the concept of robust design to fuel loading pattern design, we focus on a theoretical approach based on the higher order perturbation method. This approach indicates that the eigenvalue separation is one of the effective indices to measure the robustness of a designed fuel loading pattern. In order to verify the effectiveness of the eigenvalue separation as an index of robustness, numerical analysis is carried out for typical 3-loop PWR cores, and we evaluated the correlation between the eigenvalue separation and the variation of relative assembly power due to the perturbation of the cross section. The numerical results show that the variation of relative power decreases as the eigenvalue separation increases; thus, it is confirmed that the eigenvalue separation is an effective index of robustness. Based on the eigenvalue separation of a fuel loading pattern, we discuss design guidelines of a fuel loading pattern to improve the robustness. For example, if each fuel assembly has independent uncertainty on its cross section, the robustness of the core can be enhanced by increasing the relative power at the center of the core. The proposed guidelines will be useful to design a loading pattern that has robustness for uncertainties due to cross section, calculation method, and so on. (author)

  19. Robustness of IPSA optimized high-dose-rate prostate brachytherapy treatment plans to catheter displacements.

    Science.gov (United States)

    Poder, Joel; Whitaker, May

    2016-06-01

    Inverse planning simulated annealing (IPSA) optimized brachytherapy treatment plans are characterized with large isolated dwell times at the first or last dwell position of each catheter. The potential of catheter shifts relative to the target and organs at risk in these plans may lead to a more significant change in delivered dose to the volumes of interest relative to plans with more uniform dwell times. This study aims to determine if the Nucletron Oncentra dwell time deviation constraint (DTDC) parameter can be optimized to improve the robustness of high-dose-rate (HDR) prostate brachytherapy plans to catheter displacements. A set of 10 clinically acceptable prostate plans were re-optimized with a DTDC parameter of 0 and 0.4. For each plan, catheter displacements of 3, 7, and 14 mm were retrospectively applied and the change in dose volume histogram (DVH) indices and conformity indices analyzed. The robustness of clinically acceptable prostate plans to catheter displacements in the caudal direction was found to be dependent on the DTDC parameter. A DTDC value of 0 improves the robustness of planning target volume (PTV) coverage to catheter displacements, whereas a DTDC value of 0.4 improves the robustness of the plans to changes in hotspots. The results indicate that if used in conjunction with a pre-treatment catheter displacement correction protocol and a tolerance of 3 mm, a DTDC value of 0.4 may produce clinically superior plans. However, the effect of the DTDC parameter in plan robustness was not observed to be as strong as initially suspected.

  20. Methods and Software Architecture for Activity Recognition from Position Data

    DEFF Research Database (Denmark)

    Godsk, Torben

    This thesis describes my studies on the subject of recognizing cow activities from satellite based position data. The studies comprise methods and software architecture for activity recognition from position data, applied to cow activity recognition. The development of methods and software....... The results of these calculations are applied to a given standard machine learning algorithm, and the activity, performed by the cow as the measurements were recorded, is recognized. The software architecture integrates these methods and ensures flexible activity recognition. For instance, it is flexible...... in relation to the use of different sensors modalities and/or within different domains. In addition, the methods and their integration with the software architecture ensures both robust and accurate activity recognition. Utilized, it enables me to classify the five activities robustly and with high success...

  1. Robustness Analysis of Typologies of Reciprocal Timber Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Parigi, Dario

    2013-01-01

    to the future development of typologies of reciprocal timber structures. The paper concludes that these kinds of structures can have a potential as long span timber structures in real projects if they are carefully designed with respect to the overall robustness strategies.......Robustness of structural systems has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. In order to minimise the likelihood of such disproportionate structural failures many modern building...... codes consider the need for robustness in structures and provides strategies and methods to obtain robustness. Therefore a structural engineer may take necessary steps to design robust structures that are insensitive to accidental circumstances. The present paper outlines robustness issues related...

  2. Robust uniform persistence in discrete and continuous dynamical systems using Lyapunov exponents.

    Science.gov (United States)

    Salceanu, Paul L

    2011-07-01

    This paper extends the work of Salceanu and Smith [12, 13] where Lyapunov exponents were used to obtain conditions for uniform persistence ina class of dissipative discrete-time dynamical systems on the positive orthant of R(m), generated by maps. Here a united approach is taken, for both discrete and continuous time, and the dissipativity assumption is relaxed. Sufficient conditions are given for compact subsets of an invariant part of the boundary of R(m+) to be robust uniform weak repellers. These conditions require Lyapunov exponents be positive on such sets. It is shown how this leads to robust uniform persistence. The results apply to the investigation of robust uniform persistence of the disease in host populations, as shown in an application.

  3. Geomagnetic matching navigation algorithm based on robust estimation

    Science.gov (United States)

    Xie, Weinan; Huang, Liping; Qu, Zhenshen; Wang, Zhenhuan

    2017-08-01

    The outliers in the geomagnetic survey data seriously affect the precision of the geomagnetic matching navigation and badly disrupt its reliability. A novel algorithm which can eliminate the outliers influence is investigated in this paper. First, the weight function is designed and its principle of the robust estimation is introduced. By combining the relation equation between the matching trajectory and the reference trajectory with the Taylor series expansion for geomagnetic information, a mathematical expression of the longitude, latitude and heading errors is acquired. The robust target function is obtained by the weight function and the mathematical expression. Then the geomagnetic matching problem is converted to the solutions of nonlinear equations. Finally, Newton iteration is applied to implement the novel algorithm. Simulation results show that the matching error of the novel algorithm is decreased to 7.75% compared to the conventional mean square difference (MSD) algorithm, and is decreased to 18.39% to the conventional iterative contour matching algorithm when the outlier is 40nT. Meanwhile, the position error of the novel algorithm is 0.017° while the other two algorithms fail to match when the outlier is 400nT.

  4. Robust Linear Models for Cis-eQTL Analysis.

    Science.gov (United States)

    Rantalainen, Mattias; Lindgren, Cecilia M; Holmes, Christopher C

    2015-01-01

    Expression Quantitative Trait Loci (eQTL) analysis enables characterisation of functional genetic variation influencing expression levels of individual genes. In outbread populations, including humans, eQTLs are commonly analysed using the conventional linear model, adjusting for relevant covariates, assuming an allelic dosage model and a Gaussian error term. However, gene expression data generally have noise that induces heavy-tailed errors relative to the Gaussian distribution and often include atypical observations, or outliers. Such departures from modelling assumptions can lead to an increased rate of type II errors (false negatives), and to some extent also type I errors (false positives). Careful model checking can reduce the risk of type-I errors but often not type II errors, since it is generally too time-consuming to carefully check all models with a non-significant effect in large-scale and genome-wide studies. Here we propose the application of a robust linear model for eQTL analysis to reduce adverse effects of deviations from the assumption of Gaussian residuals. We present results from a simulation study as well as results from the analysis of real eQTL data sets. Our findings suggest that in many situations robust models have the potential to provide more reliable eQTL results compared to conventional linear models, particularly in respect to reducing type II errors due to non-Gaussian noise. Post-genomic data, such as that generated in genome-wide eQTL studies, are often noisy and frequently contain atypical observations. Robust statistical models have the potential to provide more reliable results and increased statistical power under non-Gaussian conditions. The results presented here suggest that robust models should be considered routinely alongside other commonly used methodologies for eQTL analysis.

  5. New robust chaotic system with exponential quadratic term

    International Nuclear Information System (INIS)

    Bao Bocheng; Li Chunbiao; Liu Zhong; Xu Jianping

    2008-01-01

    This paper proposes a new robust chaotic system of three-dimensional quadratic autonomous ordinary differential equations by introducing an exponential quadratic term. This system can display a double-scroll chaotic attractor with only two equilibria, and can be found to be robust chaotic in a very wide parameter domain with positive maximum Lyapunov exponent. Some basic dynamical properties and chaotic behaviour of novel attractor are studied. By numerical simulation, this paper verifies that the three-dimensional system can also evolve into periodic and chaotic behaviours by a constant controller. (general)

  6. Robust quasi NID current and flux control of an induction motor for position control

    NARCIS (Netherlands)

    van Duijnhoven, M.; Blachuta, M.J.

    1999-01-01

    In the paper, a new control design method called Dynamic Contraction method is applied to the flux and quadrature current robust control of an induction motor operated using the field orientation principle. The resulting input-output decoupled and linearized drive is then used for time-optimal

  7. Reference satellite selection method for GNSS high-precision relative positioning

    Directory of Open Access Journals (Sweden)

    Xiao Gao

    2017-03-01

    Full Text Available Selecting the optimal reference satellite is an important component of high-precision relative positioning because the reference satellite directly influences the strength of the normal equation. The reference satellite selection methods based on elevation and positional dilution of precision (PDOP value were compared. Results show that all the above methods cannot select the optimal reference satellite. We introduce condition number of the design matrix in the reference satellite selection method to improve structure of the normal equation, because condition number can indicate the ill condition of the normal equation. The experimental results show that the new method can improve positioning accuracy and reliability in precise relative positioning.

  8. Topology and robustness in the Drosophila segment polarity network.

    Directory of Open Access Journals (Sweden)

    Nicholas T Ingolia

    2004-06-01

    Full Text Available A complex hierarchy of genetic interactions converts a single-celled Drosophila melanogaster egg into a multicellular embryo with 14 segments. Previously, von Dassow et al. reported that a mathematical model of the genetic interactions that defined the polarity of segments (the segment polarity network was robust (von Dassow et al. 2000. As quantitative information about the system was unavailable, parameters were sampled randomly. A surprisingly large fraction of these parameter sets allowed the model to maintain and elaborate on the segment polarity pattern. This robustness is due to the positive feedback of gene products on their own expression, which induces individual cells in a model segment to adopt different stable expression states (bistability corresponding to different cell types in the segment polarity pattern. A positive feedback loop will only yield multiple stable states when the parameters that describe it satisfy a particular inequality. By testing which random parameter sets satisfy these inequalities, I show that bistability is necessary to form the segment polarity pattern and serves as a strong predictor of which parameter sets will succeed in forming the pattern. Although the original model was robust to parameter variation, it could not reproduce the observed effects of cell division on the pattern of gene expression. I present a modified version that incorporates recent experimental evidence and does successfully mimic the consequences of cell division. The behavior of this modified model can also be understood in terms of bistability in positive feedback of gene expression. I discuss how this topological property of networks provides robust pattern formation and how large changes in parameters can change the specific pattern produced by a network.

  9. Product integration rules at Clenshaw-Curtis and related points: A robust implementation

    International Nuclear Information System (INIS)

    Adam, G.; Nobile, A.

    1989-12-01

    Product integration rules generalizing the Fejer, Clenshaw-Curtis and Filippi quadrature rules respectively are derived for integrals with trigonometric and hyperbolic weight factors. The study puts in evidence the existence of well-conditioned fully analytic solutions, in terms of hypergeometric functions 0 F 1 . An a priori error estimator is discussed which is shown both to avoid wasteful invocation of the integration rule and to increase significantly the robustness of the automatic quadrature procedure. Then, specializing to extended Clenshaw-Curtis (ECC) rules, three types of a posteriori error estimates are considered and the existence of a great risk of their failure is put into evidence by large scale validation tests. An empirical error estimator, superseding them at slowly varying integrands, is found to result in a spectacular increase in the output reliability. Finally, enhancements in the control of the interval subdivision strategy aiming at increasing code robustness is discussed. Comparison with the code DQAWO of QUADPACK, extending over a statistics of about hundred thousand solved integrals, is illustrative for the increased robustness and error estimate reliability of our computer code implementation of the ECC rules. (author). 19 refs, 8 tabs

  10. Effects of positive relative accommodation on adolescent pseudomyopia with visual training

    Directory of Open Access Journals (Sweden)

    Jiang Yue

    2014-04-01

    Full Text Available AIM:To investigate the changes of the positive relative accommodation in adolescent pseudomyopia with visual training.METHODS: A total of 42 cases(84 eyeswere randomly divided into the visual training group and the control group. Visual acuity, average refraction of two groups 4wk after the training were measured, as well as positive relative accommodation(5mwere checked before the training and repeated 1, 2, 4wk after the training. Correlation analysis were given.RESULTS: There was statistically significant difference in visual acuity 4wk after the training between the two groups(PP>0.05. There was statistically significant difference in positive relative accommodation(5m1, 2, 4wk after the training between the two groups(PPCONCLUSION: Visual training has significant effect on the positive relative accommodation on adolescent pseudomyopia.

  11. A Two-Step Method to Identify Positive Deviant Physician Organizations of Accountable Care Organizations with Robust Performance Management Systems.

    Science.gov (United States)

    Pimperl, Alexander F; Rodriguez, Hector P; Schmittdiel, Julie A; Shortell, Stephen M

    2018-06-01

    To identify positive deviant (PD) physician organizations of Accountable Care Organizations (ACOs) with robust performance management systems (PMSYS). Third National Survey of Physician Organizations (NSPO3, n = 1,398). Organizational and external factors from NSPO3 were analyzed. Linear regression estimated the association of internal and contextual factors on PMSYS. Two cutpoints (75th/90th percentiles) identified PDs with the largest residuals and highest PMSYS scores. A total of 65 and 41 PDs were identified using 75th and 90th percentiles cutpoints, respectively. The 90th percentile more strongly differentiated PDs from non-PDs. Having a high proportion of vulnerable patients appears to constrain PMSYS development. Our PD identification method increases the likelihood that PD organizations selected for in-depth inquiry are high-performing organizations that exceed expectations. © Health Research and Educational Trust.

  12. Assessment of preschoolers’ positive empathy: concurrent and longitudinal relations with positive emotion, social competence, and sympathy

    OpenAIRE

    Sallquist, Julie; Eisenberg, Nancy; Spinrad, Tracy L.; Eggum, Natalie D.; Gaertner, Bridget M.

    2009-01-01

    The purpose of this study was to examine a new measure of children’s dispositional positive empathy (i.e., reactions to others’ positive emotions) and its concurrent and longitudinal relations with positive emotion, social competence, and empathy/sympathy with negative emotions. At Time 1, 192 3.5-year-olds (88 girls) participated; at Time 2, 1 year later, 168 4.5-year-olds (79 girls) participated. Children’s positive empathy was reported by mothers and observed in the laboratory at Time 2. A...

  13. A robust AHP-DEA method for measuring the relative efficiency: An application of airport industry

    Directory of Open Access Journals (Sweden)

    Amin Foroughi

    2012-01-01

    Full Text Available Measuring the relative efficiency of similar units has been an important topic of research among many researchers. Data envelopment analysis has been one of the most important techniques for measuring the efficiency of different units. However, there are some limitations on using such technique and some people prefer to use other methods such as analytical hierarchy process to measure the relative efficiencies. Besides, uncertainty in the input data is another issue, which makes some misleading results. In this paper, we present an integrated robust DEA-AHP to measure the relative efficiency of similar units. The proposed model of this is believed to capable of presenting better results in terms of efficiency compared with exclusive usage of DEA or AHP. The implementation of the proposed model is demonstrated for a real-world case study of Airport industry and the results are analyzed.

  14. Robust Inference with Multi-way Clustering

    OpenAIRE

    A. Colin Cameron; Jonah B. Gelbach; Douglas L. Miller; Doug Miller

    2009-01-01

    In this paper we propose a variance estimator for the OLS estimator as well as for nonlinear estimators such as logit, probit and GMM. This variance estimator enables cluster-robust inference when there is two-way or multi-way clustering that is non-nested. The variance estimator extends the standard cluster-robust variance estimator or sandwich estimator for one-way clustering (e.g. Liang and Zeger (1986), Arellano (1987)) and relies on similar relatively weak distributional assumptions. Our...

  15. Influence Function and Robust Variant of Kernel Canonical Correlation Analysis

    OpenAIRE

    Alam, Md. Ashad; Fukumizu, Kenji; Wang, Yu-Ping

    2017-01-01

    Many unsupervised kernel methods rely on the estimation of the kernel covariance operator (kernel CO) or kernel cross-covariance operator (kernel CCO). Both kernel CO and kernel CCO are sensitive to contaminated data, even when bounded positive definite kernels are used. To the best of our knowledge, there are few well-founded robust kernel methods for statistical unsupervised learning. In addition, while the influence function (IF) of an estimator can characterize its robustness, asymptotic ...

  16. Robustness of a Neural Network Model for Power Peak Factor Estimation in Protection Systems

    International Nuclear Information System (INIS)

    Souza, Rose Mary G.P.; Moreira, Joao M.L.

    2006-01-01

    This work presents results of robustness verification of artificial neural network correlations that improve the real time prediction of the power peak factor for reactor protection systems. The input variables considered in the correlation are those available in the reactor protection systems, namely, the axial power differences obtained from measured ex-core detectors, and the position of control rods. The correlations, based on radial basis function (RBF) and multilayer perceptron (MLP) neural networks, estimate the power peak factor, without faulty signals, with average errors between 0.13%, 0.19% and 0.15%, and maximum relative error of 2.35%. The robustness verification was performed for three different neural network correlations. The results show that they are robust against signal degradation, producing results with faulty signals with a maximum error of 6.90%. The average error associated to faulty signals for the MLP network is about half of that of the RBF network, and the maximum error is about 1% smaller. These results demonstrate that MLP neural network correlation is more robust than the RBF neural network correlation. The results also show that the input variables present redundant information. The axial power difference signals compensate the faulty signal for the position of a given control rod, and improves the results by about 10%. The results show that the errors in the power peak factor estimation by these neural network correlations, even in faulty conditions, are smaller than the current PWR schemes which may have uncertainties as high as 8%. Considering the maximum relative error of 2.35%, these neural network correlations would allow decreasing the power peak factor safety margin by about 5%. Such a reduction could be used for operating the reactor with a higher power level or with more flexibility. The neural network correlation has to meet requirements of high integrity software that performs safety grade actions. It is shown that the

  17. Designing a Robust Nonlinear Dynamic Inversion Controller for Spacecraft Formation Flying

    Directory of Open Access Journals (Sweden)

    Inseok Yang

    2014-01-01

    Full Text Available The robust nonlinear dynamic inversion (RNDI control technique is proposed to keep the relative position of spacecrafts while formation flying. The proposed RNDI control method is based on nonlinear dynamic inversion (NDI. NDI is nonlinear control method that replaces the original dynamics into the user-selected desired dynamics. Because NDI removes nonlinearities in the model by inverting the original dynamics directly, it also eliminates the need of designing suitable controllers for each equilibrium point; that is, NDI works as self-scheduled controller. Removing the original model also provides advantages of ease to satisfy the specific requirements by simply handling desired dynamics. Therefore, NDI is simple and has many similarities to classical control. In real applications, however, it is difficult to achieve perfect cancellation of the original dynamics due to uncertainties that lead to performance degradation and even make the system unstable. This paper proposes robustness assurance method for NDI. The proposed RNDI is designed by combining NDI and sliding mode control (SMC. SMC is inherently robust using high-speed switching inputs. This paper verifies similarities of NDI and SMC, firstly. And then RNDI control method is proposed. The performance of the proposed method is evaluated by simulations applied to spacecraft formation flying problem.

  18. Towards Robust Self-Calibration for Handheld 3d Line Laser Scanning

    Science.gov (United States)

    Bleier, M.; Nüchter, A.

    2017-11-01

    This paper studies self-calibration of a structured light system, which reconstructs 3D information using video from a static consumer camera and a handheld cross line laser projector. Intersections between the individual laser curves and geometric constraints on the relative position of the laser planes are exploited to achieve dense 3D reconstruction. This is possible without any prior knowledge of the movement of the projector. However, inaccurrately extracted laser lines introduce noise in the detected intersection positions and therefore distort the reconstruction result. Furthermore, when scanning objects with specular reflections, such as glossy painted or metalic surfaces, the reflections are often extracted from the camera image as erroneous laser curves. In this paper we investiagte how robust estimates of the parameters of the laser planes can be obtained despite of noisy detections.

  19. Attractive ellipsoids in robust control

    CERN Document Server

    Poznyak, Alexander; Azhmyakov, Vadim

    2014-01-01

    This monograph introduces a newly developed robust-control design technique for a wide class of continuous-time dynamical systems called the “attractive ellipsoid method.” Along with a coherent introduction to the proposed control design and related topics, the monograph studies nonlinear affine control systems in the presence of uncertainty and presents a constructive and easily implementable control strategy that guarantees certain stability properties. The authors discuss linear-style feedback control synthesis in the context of the above-mentioned systems. The development and physical implementation of high-performance robust-feedback controllers that work in the absence of complete information is addressed, with numerous examples to illustrate how to apply the attractive ellipsoid method to mechanical and electromechanical systems. While theorems are proved systematically, the emphasis is on understanding and applying the theory to real-world situations. Attractive Ellipsoids in Robust Control will a...

  20. Robust multivariate analysis

    CERN Document Server

    J Olive, David

    2017-01-01

    This text presents methods that are robust to the assumption of a multivariate normal distribution or methods that are robust to certain types of outliers. Instead of using exact theory based on the multivariate normal distribution, the simpler and more applicable large sample theory is given.  The text develops among the first practical robust regression and robust multivariate location and dispersion estimators backed by theory.   The robust techniques  are illustrated for methods such as principal component analysis, canonical correlation analysis, and factor analysis.  A simple way to bootstrap confidence regions is also provided. Much of the research on robust multivariate analysis in this book is being published for the first time. The text is suitable for a first course in Multivariate Statistical Analysis or a first course in Robust Statistics. This graduate text is also useful for people who are familiar with the traditional multivariate topics, but want to know more about handling data sets with...

  1. A robust method for processing scanning probe microscopy images and determining nanoobject position and dimensions

    NARCIS (Netherlands)

    Silly, F.

    2009-01-01

    P>Processing of scanning probe microscopy (SPM) images is essential to explore nanoscale phenomena. Image processing and pattern recognition techniques are developed to improve the accuracy and consistency of nanoobject and surface characterization. We present a robust and versatile method to

  2. Implications of a positive cosmological constant for general relativity.

    Science.gov (United States)

    Ashtekar, Abhay

    2017-10-01

    Most of the literature on general relativity over the last century assumes that the cosmological constant [Formula: see text] is zero. However, by now independent observations have led to a consensus that the dynamics of the universe is best described by Einstein's equations with a small but positive [Formula: see text]. Interestingly, this requires a drastic revision of conceptual frameworks commonly used in general relativity, no matter how small [Formula: see text] is. We first explain why, and then summarize the current status of generalizations of these frameworks to include a positive [Formula: see text], focusing on gravitational waves.

  3. Robustness of Structures

    DEFF Research Database (Denmark)

    Faber, Michael Havbro; Vrouwenvelder, A.C.W.M.; Sørensen, John Dalsgaard

    2011-01-01

    In 2005, the Joint Committee on Structural Safety (JCSS) together with Working Commission (WC) 1 of the International Association of Bridge and Structural Engineering (IABSE) organized a workshop on robustness of structures. Two important decisions resulted from this workshop, namely...... ‘COST TU0601: Robustness of Structures’ was initiated in February 2007, aiming to provide a platform for exchanging and promoting research in the area of structural robustness and to provide a basic framework, together with methods, strategies and guidelines enhancing robustness of structures...... the development of a joint European project on structural robustness under the COST (European Cooperation in Science and Technology) programme and the decision to develop a more elaborate document on structural robustness in collaboration between experts from the JCSS and the IABSE. Accordingly, a project titled...

  4. Attention to irrelevant cues is related to positive symptoms in schizophrenia.

    Science.gov (United States)

    Morris, Richard; Griffiths, Oren; Le Pelley, Michael E; Weickert, Thomas W

    2013-05-01

    Many modern learning theories assume that the amount of attention to a cue depends on how well that cue predicted important events in the past. Schizophrenia is associated with deficits in attention and recent theories of psychosis have argued that positive symptoms such as delusions and hallucinations are related to a failure of selective attention. However, evidence demonstrating that attention to irrelevant cues is related to positive symptoms in schizophrenia is lacking. We used a novel method of measuring attention to nonpredictive (and thus irrelevant) cues in a causal learning test (Le Pelley ME, McLaren IP. Learned associability and associative change in human causal learning. Q J Exp Psychol B. 2003;56:68-79) to assess whether healthy adults and people with schizophrenia discriminate previously predictive and nonpredictive cues. In a series of experiments with independent samples, we demonstrated: (1) when people with schizophrenia who had severe positive symptoms successfully distinguished between predictive and nonpredictive cues during training, they failed to discriminate between predictive and nonpredictive cues relative to healthy adults during subsequent testing and (2) learning about nonpredictive cues was correlated with more severe positive symptoms scores in schizophrenia. These results suggest that positive symptoms of schizophrenia are related to increased attention to nonpredictive cues during causal learning. This deficit in selective attention results in learning irrelevant causal associations and may be the basis of positive symptoms in schizophrenia.

  5. On the relation between flexibility analysis and robust optimization for linear systems

    KAUST Repository

    Zhang, Qi; Grossmann, Ignacio E.; Lima, Ricardo

    2016-01-01

    Flexibility analysis and robust optimization are two approaches to solving optimization problems under uncertainty that share some fundamental concepts, such as the use of polyhedral uncertainty sets and the worst-case approach to guarantee

  6. Replication and robustness in developmental research.

    Science.gov (United States)

    Duncan, Greg J; Engel, Mimi; Claessens, Amy; Dowsett, Chantelle J

    2014-11-01

    Replications and robustness checks are key elements of the scientific method and a staple in many disciplines. However, leading journals in developmental psychology rarely include explicit replications of prior research conducted by different investigators, and few require authors to establish in their articles or online appendices that their key results are robust across estimation methods, data sets, and demographic subgroups. This article makes the case for prioritizing both explicit replications and, especially, within-study robustness checks in developmental psychology. It provides evidence on variation in effect sizes in developmental studies and documents strikingly different replication and robustness-checking practices in a sample of journals in developmental psychology and a sister behavioral science-applied economics. Our goal is not to show that any one behavioral science has a monopoly on best practices, but rather to show how journals from a related discipline address vital concerns of replication and generalizability shared by all social and behavioral sciences. We provide recommendations for promoting graduate training in replication and robustness-checking methods and for editorial policies that encourage these practices. Although some of our recommendations may shift the form and substance of developmental research articles, we argue that they would generate considerable scientific benefits for the field. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  7. Hamiltonian Dynamics and Positive Energy in General Relativity

    Energy Technology Data Exchange (ETDEWEB)

    Deser, S. [Physics Department, Brandeis University, Waltham, MA (United States)

    1969-07-15

    A review is first given of the Hamiltonian formulation of general relativity; the gravitational field is a self-interacting massless spin-two system within the framework of ordinary Lorentz covariant field theory. The recently solved problem of positive-definiteness of the field energy is then discussed. The latter, a conserved functional of the dynamical variables, is shown to have only one extremum, a local minimum, which is the vacuum state (flat space). This implies positive energy for the field, with the vacuum as ground-state. Similar results hold when minimally coupled matter is present. (author)

  8. Defining robustness protocols: a method to include and evaluate robustness in clinical plans

    International Nuclear Information System (INIS)

    McGowan, S E; Albertini, F; Lomax, A J; Thomas, S J

    2015-01-01

    We aim to define a site-specific robustness protocol to be used during the clinical plan evaluation process. Plan robustness of 16 skull base IMPT plans to systematic range and random set-up errors have been retrospectively and systematically analysed. This was determined by calculating the error-bar dose distribution (ebDD) for all the plans and by defining some metrics used to define protocols aiding the plan assessment. Additionally, an example of how to clinically use the defined robustness database is given whereby a plan with sub-optimal brainstem robustness was identified. The advantage of using different beam arrangements to improve the plan robustness was analysed. Using the ebDD it was found range errors had a smaller effect on dose distribution than the corresponding set-up error in a single fraction, and that organs at risk were most robust to the range errors, whereas the target was more robust to set-up errors. A database was created to aid planners in terms of plan robustness aims in these volumes. This resulted in the definition of site-specific robustness protocols. The use of robustness constraints allowed for the identification of a specific patient that may have benefited from a treatment of greater individuality. A new beam arrangement showed to be preferential when balancing conformality and robustness for this case. The ebDD and error-bar volume histogram proved effective in analysing plan robustness. The process of retrospective analysis could be used to establish site-specific robustness planning protocols in proton therapy. These protocols allow the planner to determine plans that, although delivering a dosimetrically adequate dose distribution, have resulted in sub-optimal robustness to these uncertainties. For these cases the use of different beam start conditions may improve the plan robustness to set-up and range uncertainties. (paper)

  9. Defining robustness protocols: a method to include and evaluate robustness in clinical plans

    Science.gov (United States)

    McGowan, S. E.; Albertini, F.; Thomas, S. J.; Lomax, A. J.

    2015-04-01

    We aim to define a site-specific robustness protocol to be used during the clinical plan evaluation process. Plan robustness of 16 skull base IMPT plans to systematic range and random set-up errors have been retrospectively and systematically analysed. This was determined by calculating the error-bar dose distribution (ebDD) for all the plans and by defining some metrics used to define protocols aiding the plan assessment. Additionally, an example of how to clinically use the defined robustness database is given whereby a plan with sub-optimal brainstem robustness was identified. The advantage of using different beam arrangements to improve the plan robustness was analysed. Using the ebDD it was found range errors had a smaller effect on dose distribution than the corresponding set-up error in a single fraction, and that organs at risk were most robust to the range errors, whereas the target was more robust to set-up errors. A database was created to aid planners in terms of plan robustness aims in these volumes. This resulted in the definition of site-specific robustness protocols. The use of robustness constraints allowed for the identification of a specific patient that may have benefited from a treatment of greater individuality. A new beam arrangement showed to be preferential when balancing conformality and robustness for this case. The ebDD and error-bar volume histogram proved effective in analysing plan robustness. The process of retrospective analysis could be used to establish site-specific robustness planning protocols in proton therapy. These protocols allow the planner to determine plans that, although delivering a dosimetrically adequate dose distribution, have resulted in sub-optimal robustness to these uncertainties. For these cases the use of different beam start conditions may improve the plan robustness to set-up and range uncertainties.

  10. Antecedents and Dimensions of Supply Chain Robustness

    OpenAIRE

    Durach, Christian F.; Wieland, Andreas; Machuca, Jose A.D.

    2015-01-01

    Purpose – The purpose of this paper is to provide groundwork for an emerging theory of supply chain robustness – which has been conceptualized as a dimension of supply chain resilience – through reviewing and synthesizing related yet disconnected studies. The paper develops a formal definition of supply chain robustness to build a framework that captures the dimensions, antecedents and moderators of the construct as discussed in the literature. Design/methodology/approach – The...

  11. Robust cluster analysis and variable selection

    CERN Document Server

    Ritter, Gunter

    2014-01-01

    Clustering remains a vibrant area of research in statistics. Although there are many books on this topic, there are relatively few that are well founded in the theoretical aspects. In Robust Cluster Analysis and Variable Selection, Gunter Ritter presents an overview of the theory and applications of probabilistic clustering and variable selection, synthesizing the key research results of the last 50 years. The author focuses on the robust clustering methods he found to be the most useful on simulated data and real-time applications. The book provides clear guidance for the varying needs of bot

  12. Robust Parametric Control of Spacecraft Rendezvous

    Directory of Open Access Journals (Sweden)

    Dake Gu

    2014-01-01

    Full Text Available This paper proposes a method to design the robust parametric control for autonomous rendezvous of spacecrafts with the inertial information with uncertainty. We consider model uncertainty of traditional C-W equation to formulate the dynamic model of the relative motion. Based on eigenstructure assignment and model reference theory, a concise control law for spacecraft rendezvous is proposed which could be fixed through solving an optimization problem. The cost function considers the stabilization of the system and other performances. Simulation results illustrate the robustness and effectiveness of the proposed control.

  13. A Robust Cooperated Control Method with Reinforcement Learning and Adaptive H∞ Control

    Science.gov (United States)

    Obayashi, Masanao; Uchiyama, Shogo; Kuremoto, Takashi; Kobayashi, Kunikazu

    This study proposes a robust cooperated control method combining reinforcement learning with robust control to control the system. A remarkable characteristic of the reinforcement learning is that it doesn't require model formula, however, it doesn't guarantee the stability of the system. On the other hand, robust control system guarantees stability and robustness, however, it requires model formula. We employ both the actor-critic method which is a kind of reinforcement learning with minimal amount of computation to control continuous valued actions and the traditional robust control, that is, H∞ control. The proposed system was compared method with the conventional control method, that is, the actor-critic only used, through the computer simulation of controlling the angle and the position of a crane system, and the simulation result showed the effectiveness of the proposed method.

  14. Sparse and Robust Factor Modelling

    NARCIS (Netherlands)

    C. Croux (Christophe); P. Exterkate (Peter)

    2011-01-01

    textabstractFactor construction methods are widely used to summarize a large panel of variables by means of a relatively small number of representative factors. We propose a novel factor construction procedure that enjoys the properties of robustness to outliers and of sparsity; that is, having

  15. Position-momentum uncertainty relations in the presence of quantum memory

    Energy Technology Data Exchange (ETDEWEB)

    Furrer, Fabian, E-mail: furrer@eve.phys.s.u-tokyo.ac.jp [Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Berta, Mario [Institute for Quantum Information and Matter, Caltech, Pasadena, California 91125 (United States); Institute for Theoretical Physics, ETH Zurich, Wolfgang-Pauli-Str. 27, 8093 Zürich (Switzerland); Tomamichel, Marco [School of Physics, The University of Sydney, Sydney 2006 (Australia); Centre for Quantum Technologies, National University of Singapore, Singapore 117543 (Singapore); Scholz, Volkher B. [Institute for Theoretical Physics, ETH Zurich, Wolfgang-Pauli-Str. 27, 8093 Zürich (Switzerland); Christandl, Matthias [Institute for Theoretical Physics, ETH Zurich, Wolfgang-Pauli-Str. 27, 8093 Zürich (Switzerland); Department of Mathematical Sciences, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen (Denmark)

    2014-12-15

    A prominent formulation of the uncertainty principle identifies the fundamental quantum feature that no particle may be prepared with certain outcomes for both position and momentum measurements. Often the statistical uncertainties are thereby measured in terms of entropies providing a clear operational interpretation in information theory and cryptography. Recently, entropic uncertainty relations have been used to show that the uncertainty can be reduced in the presence of entanglement and to prove security of quantum cryptographic tasks. However, much of this recent progress has been focused on observables with only a finite number of outcomes not including Heisenberg’s original setting of position and momentum observables. Here, we show entropic uncertainty relations for general observables with discrete but infinite or continuous spectrum that take into account the power of an entangled observer. As an illustration, we evaluate the uncertainty relations for position and momentum measurements, which is operationally significant in that it implies security of a quantum key distribution scheme based on homodyne detection of squeezed Gaussian states.

  16. False Positive and False Negative Effects on Network Attacks

    Science.gov (United States)

    Shang, Yilun

    2018-01-01

    Robustness against attacks serves as evidence for complex network structures and failure mechanisms that lie behind them. Most often, due to detection capability limitation or good disguises, attacks on networks are subject to false positives and false negatives, meaning that functional nodes may be falsely regarded as compromised by the attacker and vice versa. In this work, we initiate a study of false positive/negative effects on network robustness against three fundamental types of attack strategies, namely, random attacks (RA), localized attacks (LA), and targeted attack (TA). By developing a general mathematical framework based upon the percolation model, we investigate analytically and by numerical simulations of attack robustness with false positive/negative rate (FPR/FNR) on three benchmark models including Erdős-Rényi (ER) networks, random regular (RR) networks, and scale-free (SF) networks. We show that ER networks are equivalently robust against RA and LA only when FPR equals zero or the initial network is intact. We find several interesting crossovers in RR and SF networks when FPR is taken into consideration. By defining the cost of attack, we observe diminishing marginal attack efficiency for RA, LA, and TA. Our finding highlights the potential risk of underestimating or ignoring FPR in understanding attack robustness. The results may provide insights into ways of enhancing robustness of network architecture and improve the level of protection of critical infrastructures.

  17. Methods for robustness programming

    NARCIS (Netherlands)

    Olieman, N.J.

    2008-01-01

    Robustness of an object is defined as the probability that an object will have properties as required. Robustness Programming (RP) is a mathematical approach for Robustness estimation and Robustness optimisation. An example in the context of designing a food product, is finding the best composition

  18. Neural processing of gendered information is more robustly associated with mothers' gendered communication with children than mothers' implicit and explicit gender stereotypes.

    Science.gov (United States)

    Endendijk, Joyce J; Spencer, Hannah; Bos, Peter A; Derks, Belle

    2018-04-26

    Processes like gender socialization (the ways in which parents convey information to their children about how girls and boys should behave) often happen unconsciously and might therefore be studied best with neuroscientific measures. We examined whether neural processing of gender-stereotype-congruent and incongruent information is more robustly related to mothers' gendered socialization of their child than mothers' implicit and explicit gender stereotypes. To this end, we examined event-related potentials (ERPs) of mothers (N = 35) completing an implicit gender-stereotype task and mothers' gender stereotypes in relation to observed gendered communication with their child (2-6 years old) in a naturalistic picture-book-reading setting. Increased N2 activity (previously related to attentional processes) to gender stimuli in the implicit gender-stereotype task was associated with mothers' positive evaluation of similar gendered behaviors and activities in the picture book they read with their child. Increased P300 activity (previously related to attention to unexpected events) to incongruent trials in the gender-stereotype task was associated with a more positive evaluation of congruent versus incongruent pictures. Compared to mothers' gender stereotypes, neural processing of gendered information was more robustly related to how mothers talk to their children about boys' and girls' stereotype-congruent and incongruent behavior, and masculine and feminine activities.

  19. A 150-year conundrum: cranial robusticity and its bearing on the origin of aboriginal australians.

    Science.gov (United States)

    Curnoe, Darren

    2011-01-20

    The origin of Aboriginal Australians has been a central question of palaeoanthropology since its inception during the 19th Century. Moreover, the idea that Australians could trace their ancestry to a non-modern Pleistocene population such as Homo erectus in Southeast Asia have existed for more than 100 years, being explicitly linked to cranial robusticity. It is argued here that in order to resolve this issue a new program of research should be embraced, one aiming to test the full range of alternative explanations for robust morphology. Recent developments in the morphological sciences, especially relating to the ontogeny of the cranium indicate that character atomisation, an approach underpinning phylogenetic reconstruction, is fraught with difficulties. This leads to the conclusion that phylogenetic-based explanations for robusticity should be reconsidered and a more parsimonious approach to explaining Aboriginal Australian origins taken. One that takes proper account of the complex processes involved in the growth of the human cranium rather than just assuming natural selection to explain every subtle variation seen in past populations. In doing so, the null hypothesis that robusticity might result from phenotypic plasticity alone cannot be rejected, a position at odds with both reticulate and deep-time continuity models of Australian origins.

  20. Robustness in laying hens

    NARCIS (Netherlands)

    Star, L.

    2008-01-01

    The aim of the project ‘The genetics of robustness in laying hens’ was to investigate nature and regulation of robustness in laying hens under sub-optimal conditions and the possibility to increase robustness by using animal breeding without loss of production. At the start of the project, a robust

  1. An IMU-Aided Body-Shadowing Error Compensation Method for Indoor Bluetooth Positioning.

    Science.gov (United States)

    Deng, Zhongliang; Fu, Xiao; Wang, Hanhua

    2018-01-20

    Research on indoor positioning technologies has recently become a hotspot because of the huge social and economic potential of indoor location-based services (ILBS). Wireless positioning signals have a considerable attenuation in received signal strength (RSS) when transmitting through human bodies, which would cause significant ranging and positioning errors in RSS-based systems. This paper mainly focuses on the body-shadowing impairment of RSS-based ranging and positioning, and derives a mathematical expression of the relation between the body-shadowing effect and the positioning error. In addition, an inertial measurement unit-aided (IMU-aided) body-shadowing detection strategy is designed, and an error compensation model is established to mitigate the effect of body-shadowing. A Bluetooth positioning algorithm with body-shadowing error compensation (BP-BEC) is then proposed to improve both the positioning accuracy and the robustness in indoor body-shadowing environments. Experiments are conducted in two indoor test beds, and the performance of both the BP-BEC algorithm and the algorithms without body-shadowing error compensation (named no-BEC) is evaluated. The results show that the BP-BEC outperforms the no-BEC by about 60.1% and 73.6% in terms of positioning accuracy and robustness, respectively. Moreover, the execution time of the BP-BEC algorithm is also evaluated, and results show that the convergence speed of the proposed algorithm has an insignificant effect on real-time localization.

  2. Robust PLS approach for KPI-related prediction and diagnosis against outliers and missing data

    Science.gov (United States)

    Yin, Shen; Wang, Guang; Yang, Xu

    2014-07-01

    In practical industrial applications, the key performance indicator (KPI)-related prediction and diagnosis are quite important for the product quality and economic benefits. To meet these requirements, many advanced prediction and monitoring approaches have been developed which can be classified into model-based or data-driven techniques. Among these approaches, partial least squares (PLS) is one of the most popular data-driven methods due to its simplicity and easy implementation in large-scale industrial process. As PLS is totally based on the measured process data, the characteristics of the process data are critical for the success of PLS. Outliers and missing values are two common characteristics of the measured data which can severely affect the effectiveness of PLS. To ensure the applicability of PLS in practical industrial applications, this paper introduces a robust version of PLS to deal with outliers and missing values, simultaneously. The effectiveness of the proposed method is finally demonstrated by the application results of the KPI-related prediction and diagnosis on an industrial benchmark of Tennessee Eastman process.

  3. A Robust Incomplete Factorization Preconditioner for Positive Definite Matrices

    Czech Academy of Sciences Publication Activity Database

    Benzi, M.; Tůma, Miroslav

    2003-01-01

    Roč. 10, - (2003), s. 385-400 ISSN 1070-5325 R&D Projects: GA AV ČR IAA2030801; GA AV ČR IAA1030103 Institutional research plan: AV0Z1030915 Keywords : sparse linear systems * positive definite matrices * preconditioned conjugate gradient s * incomplete factorization * A-orthogonalization * SAINV Subject RIV: BA - General Mathematics Impact factor: 1.042, year: 2003

  4. Age-related positivity enhancement is not universal: older Chinese look away from positive stimuli.

    Science.gov (United States)

    Fung, Helene H; Lu, Alice Y; Goren, Deborah; Isaacowitz, Derek M; Wadlinger, Heather A; Wilson, Hugh R

    2008-06-01

    Socioemotional selectivity theory postulates that with age, people are motivated to derive emotional meaning from life, leading them to pay more attention to positive relative to negative/neutral stimuli. The authors argue that cultures that differ in what they consider to be emotionally meaningful may show this preference to different extents. Using eye-tracking techniques, the authors compared visual attention toward emotional (happy, fearful, sad, and angry) and neutral facial expressions among 46 younger and 57 older Hong Kong Chinese. In contrast to prior Western findings, older but not younger Chinese looked away from happy facial expressions, suggesting that they do not show attentional preferences toward positive stimuli.

  5. A robust and fast generic voltage sag detection technique

    DEFF Research Database (Denmark)

    L. Dantas, Joacillo; Lima, Francisco Kleber A.; Branco, Carlos Gustavo C.

    2015-01-01

    In this paper, a fast and robust voltage sag detection algorithm, named VPS2D, is introduced. Using the DSOGI, the algorithm creates a virtual positive sequence voltage and monitories the fundamental voltage component of each phase. After calculating the aggregate value in the o:;3-reference fram...

  6. Robustness Analysis of Visual QA Models by Basic Questions

    KAUST Repository

    Huang, Jia-Hong

    2017-09-14

    Visual Question Answering (VQA) models should have both high robustness and accuracy. Unfortunately, most of the current VQA research only focuses on accuracy because there is a lack of proper methods to measure the robustness of VQA models. There are two main modules in our algorithm. Given a natural language question about an image, the first module takes the question as input and then outputs the ranked basic questions, with similarity scores, of the main given question. The second module takes the main question, image and these basic questions as input and then outputs the text-based answer of the main question about the given image. We claim that a robust VQA model is one, whose performance is not changed much when related basic questions as also made available to it as input. We formulate the basic questions generation problem as a LASSO optimization, and also propose a large scale Basic Question Dataset (BQD) and Rscore (novel robustness measure), for analyzing the robustness of VQA models. We hope our BQD will be used as a benchmark for to evaluate the robustness of VQA models, so as to help the community build more robust and accurate VQA models.

  7. Robustness Analysis of Visual QA Models by Basic Questions

    KAUST Repository

    Huang, Jia-Hong; Alfadly, Modar; Ghanem, Bernard

    2017-01-01

    Visual Question Answering (VQA) models should have both high robustness and accuracy. Unfortunately, most of the current VQA research only focuses on accuracy because there is a lack of proper methods to measure the robustness of VQA models. There are two main modules in our algorithm. Given a natural language question about an image, the first module takes the question as input and then outputs the ranked basic questions, with similarity scores, of the main given question. The second module takes the main question, image and these basic questions as input and then outputs the text-based answer of the main question about the given image. We claim that a robust VQA model is one, whose performance is not changed much when related basic questions as also made available to it as input. We formulate the basic questions generation problem as a LASSO optimization, and also propose a large scale Basic Question Dataset (BQD) and Rscore (novel robustness measure), for analyzing the robustness of VQA models. We hope our BQD will be used as a benchmark for to evaluate the robustness of VQA models, so as to help the community build more robust and accurate VQA models.

  8. Sexual Orientation and Spatial Position Effects on Selective Forms of Object Location Memory

    Science.gov (United States)

    Rahman, Qazi; Newland, Cherie; Smyth, Beatrice Mary

    2011-01-01

    Prior research has demonstrated robust sex and sexual orientation-related differences in object location memory in humans. Here we show that this sexual variation may depend on the spatial position of target objects and the task-specific nature of the spatial array. We tested the recovery of object locations in three object arrays (object…

  9. Robust approach to maximize the range and accuracy of force application in atomic force microscopes with nonlinear position-sensitive detectors

    International Nuclear Information System (INIS)

    Silva, E C C M; Vliet, K J van

    2006-01-01

    The atomic force microscope is used increasingly to investigate the mechanical properties of materials via sample displacement under an applied force. However, both the extent of forces attainable and the accuracy of those forces measurements are significantly limited by the optical lever configuration that is commonly used to infer nanoscale deflection of the cantilever. We present a robust and general approach to characterize and compensate for the nonlinearity of the position-sensitive optical device via data processing, requiring no modification of existing instrumentation. We demonstrate that application of this approach reduced the maximum systematic error on the gradient of a force-displacement response from 50% to 5%, and doubled the calibrated force application range. Finally, we outline an experimental protocol that optimizes the use of the quasi-linear range of the most commonly available optical feedback configurations and also accounts for the residual systematic error, allowing the user to benefit from the full detection range of these indirect force sensors

  10. Robustness of networks against propagating attacks under vaccination strategies

    International Nuclear Information System (INIS)

    Hasegawa, Takehisa; Masuda, Naoki

    2011-01-01

    We study the effect of vaccination on the robustness of networks against propagating attacks that obey the susceptible–infected–removed model. By extending the generating function formalism developed by Newman (2005 Phys. Rev. Lett. 95 108701), we analytically determine the robustness of networks that depends on the vaccination parameters. We consider the random defense where nodes are vaccinated randomly and the degree-based defense where hubs are preferentially vaccinated. We show that, when vaccines are inefficient, the random graph is more robust against propagating attacks than the scale-free network. When vaccines are relatively efficient, the scale-free network with the degree-based defense is more robust than the random graph with the random defense and the scale-free network with the random defense

  11. Effect of smoothing on robust chaos.

    Science.gov (United States)

    Deshpande, Amogh; Chen, Qingfei; Wang, Yan; Lai, Ying-Cheng; Do, Younghae

    2010-08-01

    In piecewise-smooth dynamical systems, situations can arise where the asymptotic attractors of the system in an open parameter interval are all chaotic (e.g., no periodic windows). This is the phenomenon of robust chaos. Previous works have established that robust chaos can occur through the mechanism of border-collision bifurcation, where border is the phase-space region where discontinuities in the derivatives of the dynamical equations occur. We investigate the effect of smoothing on robust chaos and find that periodic windows can arise when a small amount of smoothness is present. We introduce a parameter of smoothing and find that the measure of the periodic windows in the parameter space scales linearly with the parameter, regardless of the details of the smoothing function. Numerical support and a heuristic theory are provided to establish the scaling relation. Experimental evidence of periodic windows in a supposedly piecewise linear dynamical system, which has been implemented as an electronic circuit, is also provided.

  12. Robust photometric stereo using structural light sources

    Science.gov (United States)

    Han, Tian-Qi; Cheng, Yue; Shen, Hui-Liang; Du, Xin

    2014-05-01

    We propose a robust photometric stereo method by using structural arrangement of light sources. In the arrangement, light sources are positioned on a planar grid and form a set of collinear combinations. The shadow pixels are detected by adaptive thresholding. The specular highlight and diffuse pixels are distinguished according to their intensity deviations of the collinear combinations, thanks to the special arrangement of light sources. The highlight detection problem is cast as a pattern classification problem and is solved using support vector machine classifiers. Considering the possible misclassification of highlight pixels, the ℓ1 regularization is further employed in normal map estimation. Experimental results on both synthetic and real-world scenes verify that the proposed method can robustly recover the surface normal maps in the case of heavy specular reflection and outperforms the state-of-the-art techniques.

  13. Robustness of a bisimulation-type faster-than preorder

    Directory of Open Access Journals (Sweden)

    Katrin Iltgen

    2009-11-01

    Full Text Available TACS is an extension of CCS where upper time bounds for delays can be specified. Luettgen and Vogler defined three variants of bismulation-type faster-than relations and showed that they all three lead to the same preorder, demonstrating the robustness of their approach. In the present paper, the operational semantics of TACS is extended; it is shown that two of the variants still give the same preorder as before, underlining robustness. An explanation is given why this result fails for the third variant. It is also shown that another variant, which mixes old and new operational semantics, can lead to smaller relations that prove the same preorder.

  14. QFT Based Robust Positioning Control of the PMSM Using Automatic Loop Shaping with Teaching Learning Optimization

    Directory of Open Access Journals (Sweden)

    Nitish Katal

    2016-01-01

    Full Text Available Automation of the robust control system synthesis for uncertain systems is of great practical interest. In this paper, the loop shaping step for synthesizing quantitative feedback theory (QFT based controller for a two-phase permanent magnet stepper motor (PMSM has been automated using teaching learning-based optimization (TLBO algorithm. The QFT controller design problem has been posed as an optimization problem and TLBO algorithm has been used to minimize the proposed cost function. This facilitates designing low-order fixed-structure controller, eliminates the need of manual loop shaping step on the Nichols charts, and prevents the overdesign of the controller. A performance comparison of the designed controller has been made with the classical PID tuning method of Ziegler-Nichols and QFT controller tuned using other optimization algorithms. The simulation results show that the designed QFT controller using TLBO offers robust stability, disturbance rejection, and proper reference tracking over a range of PMSM’s parametric uncertainties as compared to the classical design techniques.

  15. Relative Physical Position as an Impression-Management Strategy: Sex Differences in Its Use and Implications.

    Science.gov (United States)

    Makhanova, Anastasia; McNulty, James K; Maner, Jon K

    2017-05-01

    People's physical position relative to others may shape how those others perceive them. The research described here suggests that people use relative physical position to manage impressions by strategically positioning themselves either higher or lower relative to ostensible observers. Five studies supported the prediction that women take and display photographs portraying themselves in a low relative physical position to highlight their youthful features and appear attractive, whereas men take and display photographs portraying themselves in a high relative physical position to highlight their size and appear dominant. The effectiveness of these strategies was confirmed in two studies that measured social perceptions of male and female targets who varied in their relative position. In sum, as do members of other social species, people use relative physical position to manage social impressions, and although these impression-management strategies may have deep ancestral roots, they appear to manifest themselves through a contemporary human modality-photographs.

  16. Evidence on the relation between public capital and Government efficiency

    OpenAIRE

    Francisca Guedes de Oliveira

    2010-01-01

    This paper intends to contribute to the literature by providing empirical evidence on the relation between public capital stock and government efficiency. We present some objective indicators fo government efficiency and explore the mentioned relation. we find a positive and significant relation between both variables that survives the introduction of controls and robustness checking.

  17. A fast high-precision six-degree-of-freedom relative position sensor

    Science.gov (United States)

    Hughes, Gary B.; Macasaet, Van P.; Griswold, Janelle; Sison, Claudia A.; Lubin, Philip; Meinhold, Peter; Suen, Jonathan; Brashears, Travis; Zhang, Qicheng; Madajian, Jonathan

    2016-03-01

    Lasers are commonly used in high-precision measurement and profiling systems. Some laser measurement systems are based on interferometry principles, and others are based on active triangulation, depending on requirements of the application. This paper describes an active triangulation laser measurement system for a specific application wherein the relative position of two fixed, rigid mechanical components is to be measured dynamically with high precision in six degrees of freedom (DOF). Potential applications include optical systems with feedback to control for mechanical vibration, such as target acquisition devices with multiple focal planes. The method uses an array of several laser emitters mounted on one component. The lasers are directed at a reflective surface on the second component. The reflective surface consists of a piecewise-planar pattern such as a pyramid, or more generally a curved reflective surface such as a hyperbolic paraboloid. The reflected spots are sensed at 2-dimensional photodiode arrays on the emitter component. Changes in the relative position of the emitter component and reflective surface will shift the location of the reflected spots within photodiode arrays. Relative motion in any degree of freedom produces independent shifts in the reflected spot locations, allowing full six-DOF relative position determination between the two component positions. Response time of the sensor is limited by the read-out rate of the photodiode arrays. Algorithms are given for position determination with limits on uncertainty and sensitivity, based on laser and spot-sensor characteristics, and assuming regular surfaces. Additional uncertainty analysis is achievable for surface irregularities based on calibration data.

  18. On the effect of ionospheric delay on geodetic relative GPS positioning

    NARCIS (Netherlands)

    Georgiadou, P.Y.; Kleusberg, A.

    1988-01-01

    Uncorrected ionospheric delay is one of the factors limiting the accuracy in geodetic relative positioning with single frequency Global Positioning System (GPS) carrier phase observations. Dual frequency measurements can be combined to eliminate the ionospheric delay in the observations. A

  19. Emotion and attention : Event-related brain potential studies

    OpenAIRE

    Schupp, Harald Thomas; Flaisch, Tobias; Stockburger, Jessica; Junghöfer, Markus

    2006-01-01

    Emotional pictures guide selective visual attention. A series of event-related brain potential (ERP) studies is reviewed demonstrating the consistent and robust modulation of specific ERP components by emotional images. Specifically, pictures depicting natural pleasant and unpleasant scenes are associated with an increased early posterior negativity, late positive potential, and sustained positive slow wave compared with neutral contents. These modulations are considered to index different st...

  20. Disclosure Decisions: HIV-Positive Persons Coping With Disease-Related Stressors

    DEFF Research Database (Denmark)

    Rodkjaer, Lotte; Sodemann, Morten; Østergaard, Lars Jørgen

    2011-01-01

    The purpose of this grounded theory study was to investigate how Danish HIV-positive persons live with their disease, focusing on HIV-related stressors. Using the Glaserian method, we analyzed textual data from in-depth interviews with 16 HIV-positive persons. Decisions about disclosure appeared ...... and plans, and offers a theoretical basis for interventions designed to assist persons living with HIV to make the best possible individual decisions regarding disclosure, and thereby reduce HIV-related stress....... to be a major concern and a determining factor for HIV-related stress. Consequently, we developed a substantive theory about disclosure decisions in which three different strategies could be identified: (a) disclosing to everyone (being open); (b) restricting disclosure (being partly open); and (c) disclosing...... to no one (being closed). Disclosure was a continuum; none of the three strategies automatically relieved HIV-related stress. The theory describes the main determinants and consequences of each strategy. Our study demonstrates the importance of recurrent individual considerations about disclosure choices...

  1. 1 nA beam position monitoring system

    International Nuclear Information System (INIS)

    Ursic, R.; Flood, R.; Piller, C.

    1997-01-01

    A system has been developed at Jefferson Lab for measuring transverse position of very low current beams delivered to the Experimental Hall B of the Continuous Electron Beam Accelerator Facility (CEBAF). At the heart of the system is a position sensitive cavity operating at 1497 MHz. The cavity utilizes a unique design which achieves a high sensitivity to beam position at a relatively low cavity Q. The cavity output RF signal is processed using a down-converter and a commercial lock-in amplifier operating at 100 kHz. The system interfaces with a VME based EPICS control system using the IEEE, 488 bus. The main features of the system are simple and robust design, and wide dynamic range capable of handling beam currents from 1 nA to 1000 nA with an expected resolution better than 100 μm. This paper outlines the design of the system

  2. [Effects of a Positive Psychotherapy Program on Positive Affect, Interpersonal Relations, Resilience, and Mental Health Recovery in Community-Dwelling People with Schizophrenia].

    Science.gov (United States)

    Kim, Jinhee; Na, Hyunjoo

    2017-10-01

    Recently, the interest in positive psychotherapy is growing, which can help to encourage positive relationships and develop strengths of people. This study was conducted to investigate the effects of a positive psychotherapy program on positive affect, interpersonal relations, resilience, and mental health recovery in community-dwelling people with schizophrenia. The research was conducted using a randomized control group pretest-posttest design. A total of 57 adults with schizophrenia participated in this study. The study participants in experimental group received a positive psychotherapy program (n=28) and the participants in control group received only the usual treatment in community centers (n=29). The positive psychotherapy program was provided for 5 weeks (of 10 sessions, held twice/week, for 60 minutes). The study outcomes included positive affect, interpersonal relations, resilience, and mental health recovery. The collected data were analyzed using repeated measures ANOVA for examining study hypothesis. Results showed that interpersonal relations (F=11.83, p=.001) and resilience (F=9.62, p=.003) significantly increased in the experimental group compared to the control group. Although experimental group showed a slight increase in positive affect, it was not significant. The study findings confirm that the positive psychotherapy program is effective for improving interpersonal relations and resilience of community-dwelling people with schizophrenia. Based on the findings, we believe that the positive psychotherapy program would be acceptable and helpful to improve recovery of mental health in schizophrenia. © 2017 Korean Society of Nursing Science

  3. Evolution favors protein mutational robustness in sufficiently large populations

    Directory of Open Access Journals (Sweden)

    Venturelli Ophelia S

    2007-07-01

    Full Text Available Abstract Background An important question is whether evolution favors properties such as mutational robustness or evolvability that do not directly benefit any individual, but can influence the course of future evolution. Functionally similar proteins can differ substantially in their robustness to mutations and capacity to evolve new functions, but it has remained unclear whether any of these differences might be due to evolutionary selection for these properties. Results Here we use laboratory experiments to demonstrate that evolution favors protein mutational robustness if the evolving population is sufficiently large. We neutrally evolve cytochrome P450 proteins under identical selection pressures and mutation rates in populations of different sizes, and show that proteins from the larger and thus more polymorphic population tend towards higher mutational robustness. Proteins from the larger population also evolve greater stability, a biophysical property that is known to enhance both mutational robustness and evolvability. The excess mutational robustness and stability is well described by mathematical theory, and can be quantitatively related to the way that the proteins occupy their neutral network. Conclusion Our work is the first experimental demonstration of the general tendency of evolution to favor mutational robustness and protein stability in highly polymorphic populations. We suggest that this phenomenon could contribute to the mutational robustness and evolvability of viruses and bacteria that exist in large populations.

  4. Manipulation Robustness of Collaborative Filtering

    OpenAIRE

    Benjamin Van Roy; Xiang Yan

    2010-01-01

    A collaborative filtering system recommends to users products that similar users like. Collaborative filtering systems influence purchase decisions and hence have become targets of manipulation by unscrupulous vendors. We demonstrate that nearest neighbors algorithms, which are widely used in commercial systems, are highly susceptible to manipulation and introduce new collaborative filtering algorithms that are relatively robust.

  5. Robust and Effective Component-based Banknote Recognition for the Blind.

    Science.gov (United States)

    Hasanuzzaman, Faiz M; Yang, Xiaodong; Tian, Yingli

    2012-11-01

    We develop a novel camera-based computer vision technology to automatically recognize banknotes for assisting visually impaired people. Our banknote recognition system is robust and effective with the following features: 1) high accuracy: high true recognition rate and low false recognition rate, 2) robustness: handles a variety of currency designs and bills in various conditions, 3) high efficiency: recognizes banknotes quickly, and 4) ease of use: helps blind users to aim the target for image capture. To make the system robust to a variety of conditions including occlusion, rotation, scaling, cluttered background, illumination change, viewpoint variation, and worn or wrinkled bills, we propose a component-based framework by using Speeded Up Robust Features (SURF). Furthermore, we employ the spatial relationship of matched SURF features to detect if there is a bill in the camera view. This process largely alleviates false recognition and can guide the user to correctly aim at the bill to be recognized. The robustness and generalizability of the proposed system is evaluated on a dataset including both positive images (with U.S. banknotes) and negative images (no U.S. banknotes) collected under a variety of conditions. The proposed algorithm, achieves 100% true recognition rate and 0% false recognition rate. Our banknote recognition system is also tested by blind users.

  6. Positioning and role of public relations in large Belgian organizations

    NARCIS (Netherlands)

    Gorp, B. van; Pauwels, L.M.A.

    2007-01-01

    This paper studies the position and role of public relations in the hierarchical structure of Belgian organizations of at least 50 employees. Empirical data was collected from a web survey (n = 750) to find out to what extent principles of excellence in public relations are applied in Belgium. The

  7. Predictive IP controller for robust position control of linear servo system.

    Science.gov (United States)

    Lu, Shaowu; Zhou, Fengxing; Ma, Yajie; Tang, Xiaoqi

    2016-07-01

    Position control is a typical application of linear servo system. In this paper, to reduce the system overshoot, an integral plus proportional (IP) controller is used in the position control implementation. To further improve the control performance, a gain-tuning IP controller based on a generalized predictive control (GPC) law is proposed. Firstly, to represent the dynamics of the position loop, a second-order linear model is used and its model parameters are estimated on-line by using a recursive least squares method. Secondly, based on the GPC law, an optimal control sequence is obtained by using receding horizon, then directly supplies the IP controller with the corresponding control parameters in the real operations. Finally, simulation and experimental results are presented to show the efficiency of proposed scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  8. Two-level Robust Measurement Fusion Kalman Filter for Clustering Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    ZHANG Peng; QI Wen-Juan; DENG Zi-Li

    2014-01-01

    This paper investigates the distributed fusion Kalman filtering over clustering sensor networks. The sensor network is partitioned as clusters by the nearest neighbor rule and each cluster consists of sensing nodes and cluster-head. Using the minimax robust estimation principle, based on the worst-case conservative system with the conservative upper bounds of noise variances, two-level robust measurement fusion Kalman filter is presented for the clustering sensor network systems with uncertain noise variances. It can significantly reduce the communication load and save energy when the number of sensors is very large. A Lyapunov equation approach for the robustness analysis is presented, by which the robustness of the local and fused Kalman filters is proved. The concept of the robust accuracy is presented, and the robust accuracy relations among the local and fused robust Kalman filters are proved. It is proved that the robust accuracy of the two-level weighted measurement fuser is equal to that of the global centralized robust fuser and is higher than those of each local robust filter and each local weighted measurement fuser. A simulation example shows the correctness and effectiveness of the proposed results.

  9. Effects of positive relative accommodation on adolescent pseudomyopia with visual training

    OpenAIRE

    Jiang Yue; Hui Yue; Qiu-Jin Ren; Qing Zhou; Jing Huang

    2014-01-01

    AIM:To investigate the changes of the positive relative accommodation in adolescent pseudomyopia with visual training.METHODS: A total of 42 cases(84 eyes)were randomly divided into the visual training group and the control group. Visual acuity, average refraction of two groups 4wk after the training were measured, as well as positive relative accommodation(5m)were checked before the training and repeated 1, 2, 4wk after the training. Correlation analysis were given.RESULTS: There was statist...

  10. An IMU-Aided Body-Shadowing Error Compensation Method for Indoor Bluetooth Positioning

    Directory of Open Access Journals (Sweden)

    Zhongliang Deng

    2018-01-01

    Full Text Available Research on indoor positioning technologies has recently become a hotspot because of the huge social and economic potential of indoor location-based services (ILBS. Wireless positioning signals have a considerable attenuation in received signal strength (RSS when transmitting through human bodies, which would cause significant ranging and positioning errors in RSS-based systems. This paper mainly focuses on the body-shadowing impairment of RSS-based ranging and positioning, and derives a mathematical expression of the relation between the body-shadowing effect and the positioning error. In addition, an inertial measurement unit-aided (IMU-aided body-shadowing detection strategy is designed, and an error compensation model is established to mitigate the effect of body-shadowing. A Bluetooth positioning algorithm with body-shadowing error compensation (BP-BEC is then proposed to improve both the positioning accuracy and the robustness in indoor body-shadowing environments. Experiments are conducted in two indoor test beds, and the performance of both the BP-BEC algorithm and the algorithms without body-shadowing error compensation (named no-BEC is evaluated. The results show that the BP-BEC outperforms the no-BEC by about 60.1% and 73.6% in terms of positioning accuracy and robustness, respectively. Moreover, the execution time of the BP-BEC algorithm is also evaluated, and results show that the convergence speed of the proposed algorithm has an insignificant effect on real-time localization.

  11. The emotional content of life stories: Positivity bias and relation to personality

    DEFF Research Database (Denmark)

    Thomsen, Dorthe Kirkegaard; Olesen, Martin Hammershøj; Schnieber, Anette

    2014-01-01

    . Three hundred ten students and 160 middle-aged adults completed a measure of personality traits and identified chapters as well as past and future events in their life story. All life story components were rated on emotion and age. Negative future events were less likely to be a continuation of chapters...... and were more temporally distant than positive future events. Extraversion and Conscientiousness were related to more positive life stories, and Neuroticism was related to more negative life stories. This suggests that the life story is positively biased by minimising the negative future...

  12. A robust response to combination immune checkpoint inhibitor therapy in HPV-related small cell cancer: a case report.

    Science.gov (United States)

    Ho, Won Jin; Rooper, Lisa; Sagorsky, Sarah; Kang, Hyunseok

    2018-05-09

    Human papillomavirus-related small cell carcinoma of the head and neck is an extremely rare, aggressive subtype with poor outcomes. Therapeutic options are limited and are largely adopted from small cell lung cancer treatment paradigms. This report describes a 69-year old male who was diagnosed of HPV-related oropharyngeal cancer with mixed small cell and squamous cell pathology which was clinically aggressive and progressed through multimodal platinum-based therapies. Upon manifestation of worsening metastatic disease, the patient was initiated on a combination of ipilimumab and nivolumab. Within 2 months of starting immunotherapy, a robust partial response was observed. During the treatment course, the patient developed immune-related adverse effects including new diabetes mellitus, colitis, and hypothyroidism. The disease-specific survival was 26 months. Combination immunotherapy may be an attractive option for HPV-related small cell head and neck cancers resistant to other treatment modalities and thus warrants further evaluation.

  13. Computation of robustly stabilizing PID controllers for interval systems.

    Science.gov (United States)

    Matušů, Radek; Prokop, Roman

    2016-01-01

    The paper is focused on the computation of all possible robustly stabilizing Proportional-Integral-Derivative (PID) controllers for plants with interval uncertainty. The main idea of the proposed method is based on Tan's (et al.) technique for calculation of (nominally) stabilizing PI and PID controllers or robustly stabilizing PI controllers by means of plotting the stability boundary locus in either P-I plane or P-I-D space. Refinement of the existing method by consideration of 16 segment plants instead of 16 Kharitonov plants provides an elegant and efficient tool for finding all robustly stabilizing PID controllers for an interval system. The validity and relatively effortless application of presented theoretical concepts are demonstrated through a computation and simulation example in which the uncertain mathematical model of an experimental oblique wing aircraft is robustly stabilized.

  14. Robust Control with Enlaeged Interval of Uncertain Parameters

    Directory of Open Access Journals (Sweden)

    Marek Keresturi

    2002-01-01

    Full Text Available Robust control is advantageous for systems with defined interval of uncertain parameters. This can be substantially enlarged dividing it into a few sub-intervals. Corresponding controllers for each of them may be set after approximate identification of some uncertain plant parameters. The paper deals with application of the pole region assignment method for position control of the crane crab. The same track form is required for uncertain burden mass and approximate value of rope length. Measurement of crab position and speed is supposed, burden deviation angle is observed. Simulation results have verified feasibility of this design procedure.

  15. Robustness of structures

    DEFF Research Database (Denmark)

    Vrouwenvelder, T.; Sørensen, John Dalsgaard

    2009-01-01

    After the collapse of the World Trade Centre towers in 2001 and a number of collapses of structural systems in the beginning of the century, robustness of structural systems has gained renewed interest. Despite many significant theoretical, methodical and technological advances, structural...... of robustness for structural design such requirements are not substantiated in more detail, nor have the engineering profession been able to agree on an interpretation of robustness which facilitates for its uantification. A European COST action TU 601 on ‘Robustness of structures' has started in 2007...... by a group of members of the CSS. This paper describes the ongoing work in this action, with emphasis on the development of a theoretical and risk based quantification and optimization procedure on the one side and a practical pre-normative guideline on the other....

  16. Robust second-order scheme for multi-phase flow computations

    Science.gov (United States)

    Shahbazi, Khosro

    2017-06-01

    A robust high-order scheme for the multi-phase flow computations featuring jumps and discontinuities due to shock waves and phase interfaces is presented. The scheme is based on high-order weighted-essentially non-oscillatory (WENO) finite volume schemes and high-order limiters to ensure the maximum principle or positivity of the various field variables including the density, pressure, and order parameters identifying each phase. The two-phase flow model considered besides the Euler equations of gas dynamics consists of advection of two parameters of the stiffened-gas equation of states, characterizing each phase. The design of the high-order limiter is guided by the findings of Zhang and Shu (2011) [36], and is based on limiting the quadrature values of the density, pressure and order parameters reconstructed using a high-order WENO scheme. The proof of positivity-preserving and accuracy is given, and the convergence and the robustness of the scheme are illustrated using the smooth isentropic vortex problem with very small density and pressure. The effectiveness and robustness of the scheme in computing the challenging problem of shock wave interaction with a cluster of tightly packed air or helium bubbles placed in a body of liquid water is also demonstrated. The superior performance of the high-order schemes over the first-order Lax-Friedrichs scheme for computations of shock-bubble interaction is also shown. The scheme is implemented in two-dimensional space on parallel computers using message passing interface (MPI). The proposed scheme with limiter features approximately 50% higher number of inter-processor message communications compared to the corresponding scheme without limiter, but with only 10% higher total CPU time. The scheme is provably second-order accurate in regions requiring positivity enforcement and higher order in the rest of domain.

  17. Sufficient conditions for BIBO robust stabilization : given by the gap metric

    NARCIS (Netherlands)

    Zhu, S.Q.; Hautus, M.L.J.; Praagman, C.

    1987-01-01

    A relation between coprlme fractions and the gap metric is presented. Using this result we provide some sufficient conditions for BIBO robust stabilization for a very wide class of systems. These conditions allow the plant and compensator to be disturbed simultaneously. Keywords: Robust

  18. Robustness of Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2008-01-01

    This paper describes the background of the robustness requirements implemented in the Danish Code of Practice for Safety of Structures and in the Danish National Annex to the Eurocode 0, see (DS-INF 146, 2003), (DS 409, 2006), (EN 1990 DK NA, 2007) and (Sørensen and Christensen, 2006). More...... frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of new structures essential....... According to Danish design rules robustness shall be documented for all structures in high consequence class. The design procedure to document sufficient robustness consists of: 1) Review of loads and possible failure modes / scenarios and determination of acceptable collapse extent; 2) Review...

  19. Dynamics robustness of cascading systems.

    Directory of Open Access Journals (Sweden)

    Jonathan T Young

    2017-03-01

    Full Text Available A most important property of biochemical systems is robustness. Static robustness, e.g., homeostasis, is the insensitivity of a state against perturbations, whereas dynamics robustness, e.g., homeorhesis, is the insensitivity of a dynamic process. In contrast to the extensively studied static robustness, dynamics robustness, i.e., how a system creates an invariant temporal profile against perturbations, is little explored despite transient dynamics being crucial for cellular fates and are reported to be robust experimentally. For example, the duration of a stimulus elicits different phenotypic responses, and signaling networks process and encode temporal information. Hence, robustness in time courses will be necessary for functional biochemical networks. Based on dynamical systems theory, we uncovered a general mechanism to achieve dynamics robustness. Using a three-stage linear signaling cascade as an example, we found that the temporal profiles and response duration post-stimulus is robust to perturbations against certain parameters. Then analyzing the linearized model, we elucidated the criteria of when signaling cascades will display dynamics robustness. We found that changes in the upstream modules are masked in the cascade, and that the response duration is mainly controlled by the rate-limiting module and organization of the cascade's kinetics. Specifically, we found two necessary conditions for dynamics robustness in signaling cascades: 1 Constraint on the rate-limiting process: The phosphatase activity in the perturbed module is not the slowest. 2 Constraints on the initial conditions: The kinase activity needs to be fast enough such that each module is saturated even with fast phosphatase activity and upstream changes are attenuated. We discussed the relevance of such robustness to several biological examples and the validity of the above conditions therein. Given the applicability of dynamics robustness to a variety of systems, it

  20. Impacts of Satellite Orbit and Clock on Real-Time GPS Point and Relative Positioning.

    Science.gov (United States)

    Shi, Junbo; Wang, Gaojing; Han, Xianquan; Guo, Jiming

    2017-06-12

    Satellite orbit and clock corrections are always treated as known quantities in GPS positioning models. Therefore, any error in the satellite orbit and clock products will probably cause significant consequences for GPS positioning, especially for real-time applications. Currently three types of satellite products have been made available for real-time positioning, including the broadcast ephemeris, the International GNSS Service (IGS) predicted ultra-rapid product, and the real-time product. In this study, these three predicted/real-time satellite orbit and clock products are first evaluated with respect to the post-mission IGS final product, which demonstrates cm to m level orbit accuracies and sub-ns to ns level clock accuracies. Impacts of real-time satellite orbit and clock products on GPS point and relative positioning are then investigated using the P3 and GAMIT software packages, respectively. Numerical results show that the real-time satellite clock corrections affect the point positioning more significantly than the orbit corrections. On the contrary, only the real-time orbit corrections impact the relative positioning. Compared with the positioning solution using the IGS final product with the nominal orbit accuracy of ~2.5 cm, the real-time broadcast ephemeris with ~2 m orbit accuracy provided <2 cm relative positioning error for baselines no longer than 216 km. As for the baselines ranging from 574 to 2982 km, the cm-dm level positioning error was identified for the relative positioning solution using the broadcast ephemeris. The real-time product could result in <5 mm relative positioning accuracy for baselines within 2982 km, slightly better than the predicted ultra-rapid product.

  1. Impacts of Satellite Orbit and Clock on Real-Time GPS Point and Relative Positioning

    Directory of Open Access Journals (Sweden)

    Junbo Shi

    2017-06-01

    Full Text Available Satellite orbit and clock corrections are always treated as known quantities in GPS positioning models. Therefore, any error in the satellite orbit and clock products will probably cause significant consequences for GPS positioning, especially for real-time applications. Currently three types of satellite products have been made available for real-time positioning, including the broadcast ephemeris, the International GNSS Service (IGS predicted ultra-rapid product, and the real-time product. In this study, these three predicted/real-time satellite orbit and clock products are first evaluated with respect to the post-mission IGS final product, which demonstrates cm to m level orbit accuracies and sub-ns to ns level clock accuracies. Impacts of real-time satellite orbit and clock products on GPS point and relative positioning are then investigated using the P3 and GAMIT software packages, respectively. Numerical results show that the real-time satellite clock corrections affect the point positioning more significantly than the orbit corrections. On the contrary, only the real-time orbit corrections impact the relative positioning. Compared with the positioning solution using the IGS final product with the nominal orbit accuracy of ~2.5 cm, the real-time broadcast ephemeris with ~2 m orbit accuracy provided <2 cm relative positioning error for baselines no longer than 216 km. As for the baselines ranging from 574 to 2982 km, the cm–dm level positioning error was identified for the relative positioning solution using the broadcast ephemeris. The real-time product could result in <5 mm relative positioning accuracy for baselines within 2982 km, slightly better than the predicted ultra-rapid product.

  2. Robust and distributed hypothesis testing

    CERN Document Server

    Gül, Gökhan

    2017-01-01

    This book generalizes and extends the available theory in robust and decentralized hypothesis testing. In particular, it presents a robust test for modeling errors which is independent from the assumptions that a sufficiently large number of samples is available, and that the distance is the KL-divergence. Here, the distance can be chosen from a much general model, which includes the KL-divergence as a very special case. This is then extended by various means. A minimax robust test that is robust against both outliers as well as modeling errors is presented. Minimax robustness properties of the given tests are also explicitly proven for fixed sample size and sequential probability ratio tests. The theory of robust detection is extended to robust estimation and the theory of robust distributed detection is extended to classes of distributions, which are not necessarily stochastically bounded. It is shown that the quantization functions for the decision rules can also be chosen as non-monotone. Finally, the boo...

  3. Robustness Property of Robust-BD Wald-Type Test for Varying-Dimensional General Linear Models

    Directory of Open Access Journals (Sweden)

    Xiao Guo

    2018-03-01

    Full Text Available An important issue for robust inference is to examine the stability of the asymptotic level and power of the test statistic in the presence of contaminated data. Most existing results are derived in finite-dimensional settings with some particular choices of loss functions. This paper re-examines this issue by allowing for a diverging number of parameters combined with a broader array of robust error measures, called “robust- BD ”, for the class of “general linear models”. Under regularity conditions, we derive the influence function of the robust- BD parameter estimator and demonstrate that the robust- BD Wald-type test enjoys the robustness of validity and efficiency asymptotically. Specifically, the asymptotic level of the test is stable under a small amount of contamination of the null hypothesis, whereas the asymptotic power is large enough under a contaminated distribution in a neighborhood of the contiguous alternatives, thus lending supports to the utility of the proposed robust- BD Wald-type test.

  4. Robust control synthesis for uncertain dynamical systems

    Science.gov (United States)

    Byun, Kuk-Whan; Wie, Bong; Sunkel, John

    1989-01-01

    This paper presents robust control synthesis techniques for uncertain dynamical systems subject to structured parameter perturbation. Both QFT (quantitative feedback theory) and H-infinity control synthesis techniques are investigated. Although most H-infinity-related control techniques are not concerned with the structured parameter perturbation, a new way of incorporating the parameter uncertainty in the robust H-infinity control design is presented. A generic model of uncertain dynamical systems is used to illustrate the design methodologies investigated in this paper. It is shown that, for a certain noncolocated structural control problem, use of both techniques results in nonminimum phase compensation.

  5. MiR-192-Mediated Positive Feedback Loop Controls the Robustness of Stress-Induced p53 Oscillations in Breast Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Richard Moore

    2015-12-01

    Full Text Available The p53 tumor suppressor protein plays a critical role in cellular stress and cancer prevention. A number of post-transcriptional regulators, termed microRNAs, are closely connected with the p53-mediated cellular networks. While the molecular interactions among p53 and microRNAs have emerged, a systems-level understanding of the regulatory mechanism and the role of microRNAs-forming feedback loops with the p53 core remains elusive. Here we have identified from literature that there exist three classes of microRNA-mediated feedback loops revolving around p53, all with the nature of positive feedback coincidentally. To explore the relationship between the cellular performance of p53 with the microRNA feedback pathways, we developed a mathematical model of the core p53-MDM2 module coupled with three microRNA-mediated positive feedback loops involving miR-192, miR-34a, and miR-29a. Simulations and bifurcation analysis in relationship to extrinsic noise reproduce the oscillatory behavior of p53 under DNA damage in single cells, and notably show that specific microRNA abrogation can disrupt the wild-type cellular phenotype when the ubiquitous cell-to-cell variability is taken into account. To assess these in silico results we conducted microRNA-perturbation experiments in MCF7 breast cancer cells. Time-lapse microscopy of cell-population behavior in response to DNA double-strand breaks, together with image classification of single-cell phenotypes across a population, confirmed that the cellular p53 oscillations are compromised after miR-192 perturbations, matching well with the model predictions. Our study via modeling in combination with quantitative experiments provides new evidence on the role of microRNA-mediated positive feedback loops in conferring robustness to the system performance of stress-induced response of p53.

  6. Parental educational practices in relation to children's anxiety disorder-related behavior.

    Science.gov (United States)

    Mellon, Robert C; Moutavelis, Adrianos G

    2011-08-01

    Schoolchildren reported their parents' use of aversive control and positive reinforcement contingencies in their educational interventions, as well as parental non-responsiveness to their requests for educational assistance. They also reported their own levels of six dimensions of anxiety disorder-related phenomena. Both parental use of aversive control and non-responsiveness were directly related to overall levels of child anxiety disorder-related behavior; these correlations were more robust than those observed in previous investigations of more diffuse dimensions of parenting style and trait anxiety. Panic disorder/agoraphobia and Generalized anxiety disorder were the dimensions most strongly correlated with both parental aversive control and non-responsiveness, while Compulsive behavior was uniquely uncorrelated with parental non-responsiveness and uniquely correlated with parental use of positive reinforcement contingencies. Differences in the magnitudes of correlations between anxiety disorder-related dimensions and parental educational practices are interpreted in terms of the probable differential effectiveness of their constituent behaviors in terminating parent-mediated negative reinforcers. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Robustness Analysis of Visual Question Answering Models by Basic Questions

    KAUST Repository

    Huang, Jia-Hong

    2017-11-01

    Visual Question Answering (VQA) models should have both high robustness and accuracy. Unfortunately, most of the current VQA research only focuses on accuracy because there is a lack of proper methods to measure the robustness of VQA models. There are two main modules in our algorithm. Given a natural language question about an image, the first module takes the question as input and then outputs the ranked basic questions, with similarity scores, of the main given question. The second module takes the main question, image and these basic questions as input and then outputs the text-based answer of the main question about the given image. We claim that a robust VQA model is one, whose performance is not changed much when related basic questions as also made available to it as input. We formulate the basic questions generation problem as a LASSO optimization, and also propose a large scale Basic Question Dataset (BQD) and Rscore (novel robustness measure), for analyzing the robustness of VQA models. We hope our BQD will be used as a benchmark for to evaluate the robustness of VQA models, so as to help the community build more robust and accurate VQA models.

  8. Robustness Analysis of Visual Question Answering Models by Basic Questions

    KAUST Repository

    Huang, Jia-Hong

    2017-01-01

    Visual Question Answering (VQA) models should have both high robustness and accuracy. Unfortunately, most of the current VQA research only focuses on accuracy because there is a lack of proper methods to measure the robustness of VQA models. There are two main modules in our algorithm. Given a natural language question about an image, the first module takes the question as input and then outputs the ranked basic questions, with similarity scores, of the main given question. The second module takes the main question, image and these basic questions as input and then outputs the text-based answer of the main question about the given image. We claim that a robust VQA model is one, whose performance is not changed much when related basic questions as also made available to it as input. We formulate the basic questions generation problem as a LASSO optimization, and also propose a large scale Basic Question Dataset (BQD) and Rscore (novel robustness measure), for analyzing the robustness of VQA models. We hope our BQD will be used as a benchmark for to evaluate the robustness of VQA models, so as to help the community build more robust and accurate VQA models.

  9. An effective method to improve the robustness of small-world networks under attack

    International Nuclear Information System (INIS)

    Zhang Zheng-Zhen; Xu Wen-Jun; Lin Jia-Ru; Zeng Shang-You

    2014-01-01

    In this study, the robustness of small-world networks to three types of attack is investigated. Global efficiency is introduced as the network coefficient to measure the robustness of a small-world network. The simulation results prove that an increase in rewiring probability or average degree can enhance the robustness of the small-world network under all three types of attack. The effectiveness of simultaneously increasing both rewiring probability and average degree is also studied, and the combined increase is found to significantly improve the robustness of the small-world network. Furthermore, the combined effect of rewiring probability and average degree on network robustness is shown to be several times greater than that of rewiring probability or average degree individually. This means that small-world networks with a relatively high rewiring probability and average degree have advantages both in network communications and in good robustness to attacks. Therefore, simultaneously increasing rewiring probability and average degree is an effective method of constructing realistic networks. Consequently, the proposed method is useful to construct efficient and robust networks in a realistic scenario. (interdisciplinary physics and related areas of science and technology)

  10. Robust and Sparse Factor Modelling

    DEFF Research Database (Denmark)

    Croux, Christophe; Exterkate, Peter

    Factor construction methods are widely used to summarize a large panel of variables by means of a relatively small number of representative factors. We propose a novel factor construction procedure that enjoys the properties of robustness to outliers and of sparsity; that is, having relatively few...... nonzero factor loadings. Compared to the traditional factor construction method, we find that this procedure leads to a favorable forecasting performance in the presence of outliers and to better interpretable factors. We investigate the performance of the method in a Monte Carlo experiment...

  11. High precision relative position sensing system for formation flying spacecraft

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop and test an optical sensing system that provides high precision relative position sensing for formation flying spacecraft.  A high precision...

  12. The variation management framework (VMF): A unifying graphical representation of robust design

    DEFF Research Database (Denmark)

    Howard, Thomas J.; Eifler, Tobias; Pedersen, Søren Nygaard

    2017-01-01

    In this article a framework for robust design and variation management is proposed by combining central models to Robust Design, namely, the Quality Loss Function, the Transfer Function, and the Domains of Axiomatic Design. The Variation Management Framework (VMF) shows how variation can be mapped...... from production variation right through to the quality loss perceived by the customer for a single characteristic chain. Seven levers which can be activated to increase product quality are described and positioned on the VMF and variation metrics are proposed....

  13. Selfing ability and dispersal are positively related, but not affected by range position: a multispecies study on southern African Asteraceae.

    Science.gov (United States)

    de Waal, C; Rodger, J G; Anderson, B; Ellis, A G

    2014-05-01

    Dispersal and breeding system traits are thought to affect colonization success. As species have attained their present distribution ranges through colonization, these traits may vary geographically. Although several theories predict associations between dispersal ability, selfing ability and the relative position of a population within its geographic range, there is little theoretical or empirical consensus on exactly how these three variables are related. We investigated relationships between dispersal ability, selfing ability and range position across 28 populations of 13 annual, wind-dispersed Asteraceae species from the Namaqualand region of South Africa. Controlling for phylogeny, relative dispersal ability--assessed from vertical fall time of fruits--was positively related to an index of autofertility--determined from hand-pollination experiments. These findings support the existence of two discrete syndromes: high selfing ability associated with good dispersal and obligate outcrossing associated with lower dispersal ability. This is consistent with the hypothesis that selection for colonization success drives the evolution of an association between these traits. However, no general effect of range position on dispersal or breeding system traits was evident. This suggests selection on both breeding system and dispersal traits acts consistently across distribution ranges. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  14. Robustness Beamforming Algorithms

    Directory of Open Access Journals (Sweden)

    Sajad Dehghani

    2014-04-01

    Full Text Available Adaptive beamforming methods are known to degrade in the presence of steering vector and covariance matrix uncertinity. In this paper, a new approach is presented to robust adaptive minimum variance distortionless response beamforming make robust against both uncertainties in steering vector and covariance matrix. This method minimize a optimization problem that contains a quadratic objective function and a quadratic constraint. The optimization problem is nonconvex but is converted to a convex optimization problem in this paper. It is solved by the interior-point method and optimum weight vector to robust beamforming is achieved.

  15. Robust estimation of event-related potentials via particle filter.

    Science.gov (United States)

    Fukami, Tadanori; Watanabe, Jun; Ishikawa, Fumito

    2016-03-01

    In clinical examinations and brain-computer interface (BCI) research, a short electroencephalogram (EEG) measurement time is ideal. The use of event-related potentials (ERPs) relies on both estimation accuracy and processing time. We tested a particle filter that uses a large number of particles to construct a probability distribution. We constructed a simple model for recording EEG comprising three components: ERPs approximated via a trend model, background waves constructed via an autoregressive model, and noise. We evaluated the performance of the particle filter based on mean squared error (MSE), P300 peak amplitude, and latency. We then compared our filter with the Kalman filter and a conventional simple averaging method. To confirm the efficacy of the filter, we used it to estimate ERP elicited by a P300 BCI speller. A 400-particle filter produced the best MSE. We found that the merit of the filter increased when the original waveform already had a low signal-to-noise ratio (SNR) (i.e., the power ratio between ERP and background EEG). We calculated the amount of averaging necessary after applying a particle filter that produced a result equivalent to that associated with conventional averaging, and determined that the particle filter yielded a maximum 42.8% reduction in measurement time. The particle filter performed better than both the Kalman filter and conventional averaging for a low SNR in terms of both MSE and P300 peak amplitude and latency. For EEG data produced by the P300 speller, we were able to use our filter to obtain ERP waveforms that were stable compared with averages produced by a conventional averaging method, irrespective of the amount of averaging. We confirmed that particle filters are efficacious in reducing the measurement time required during simulations with a low SNR. Additionally, particle filters can perform robust ERP estimation for EEG data produced via a P300 speller. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. A Robust Vision-based Runway Detection and Tracking Algorithm for Automatic UAV Landing

    KAUST Repository

    Abu Jbara, Khaled F.

    2015-05-01

    This work presents a novel real-time algorithm for runway detection and tracking applied to the automatic takeoff and landing of Unmanned Aerial Vehicles (UAVs). The algorithm is based on a combination of segmentation based region competition and the minimization of a specific energy function to detect and identify the runway edges from streaming video data. The resulting video-based runway position estimates are updated using a Kalman Filter, which can integrate other sensory information such as position and attitude angle estimates to allow a more robust tracking of the runway under turbulence. We illustrate the performance of the proposed lane detection and tracking scheme on various experimental UAV flights conducted by the Saudi Aerospace Research Center. Results show an accurate tracking of the runway edges during the landing phase under various lighting conditions. Also, it suggests that such positional estimates would greatly improve the positional accuracy of the UAV during takeoff and landing phases. The robustness of the proposed algorithm is further validated using Hardware in the Loop simulations with diverse takeoff and landing videos generated using a commercial flight simulator.

  17. Robust Parameter and Signal Estimation in Induction Motors

    DEFF Research Database (Denmark)

    Børsting, H.

    This thesis deals with theories and methods for robust parameter and signal estimation in induction motors. The project originates in industrial interests concerning sensor-less control of electrical drives. During the work, some general problems concerning estimation of signals and parameters...... in nonlinear systems, have been exposed. The main objectives of this project are: - analysis and application of theories and methods for robust estimation of parameters in a model structure, obtained from knowledge of the physics of the induction motor. - analysis and application of theories and methods...... for robust estimation of the rotor speed and driving torque of the induction motor based only on measurements of stator voltages and currents. Only contimuous-time models have been used, which means that physical related signals and parameters are estimated directly and not indirectly by some discrete...

  18. Position-momentum uncertainty relations in the presence of quantum memory

    DEFF Research Database (Denmark)

    Furrer, Fabian; Berta, Mario; Tomamichel, Marco

    2014-01-01

    A prominent formulation of the uncertainty principle identifies the fundamental quantum feature that no particle may be prepared with certain outcomes for both position and momentum measurements. Often the statistical uncertainties are thereby measured in terms of entropies providing a clear oper....... As an illustration, we evaluate the uncertainty relations for position and momentum measurements, which is operationally significant in that it implies security of a quantum key distribution scheme based on homodyne detection of squeezed Gaussian states....

  19. Optically initialized robust valley-polarized holes in monolayer WSe2

    KAUST Repository

    Hsu, Wei-Ting

    2015-11-25

    A robust valley polarization is a key prerequisite for exploiting valley pseudospin to carry information in next-generation electronics and optoelectronics. Although monolayer transition metal dichalcogenides with inherent spin–valley coupling offer a unique platform to develop such valleytronic devices, the anticipated long-lived valley pseudospin has not been observed yet. Here we demonstrate that robust valley-polarized holes in monolayer WSe2 can be initialized by optical pumping. Using time-resolved Kerr rotation spectroscopy, we observe a long-lived valley polarization for positive trion with a lifetime approaching 1 ns at low temperatures, which is much longer than the trion recombination lifetime (~10–20 ps). The long-lived valley polarization arises from the transfer of valley pseudospin from photocarriers to resident holes in a specific valley. The optically initialized valley pseudospin of holes remains robust even at room temperature, which opens up the possibility to realize room-temperature valleytronics based on transition metal dichalcogenides.

  20. Is aerobic workload positively related to ambulatory blood pressure?

    DEFF Research Database (Denmark)

    Korshøj, Mette; Clays, Els; Lidegaard, Mark

    2016-01-01

    workload and ambulatory blood pressure (ABP) are lacking. The aim was to explore the relationship between objectively measured relative aerobic workload and ABP. METHODS: A total of 116 cleaners aged 18-65 years were included after informed consent was obtained. A portable device (Spacelabs 90217......) was mounted for 24-h measurements of ABP, and an Actiheart was mounted for 24-h heart rate measurements to calculate relative aerobic workload as percentage of relative heart rate reserve. A repeated-measure multi-adjusted mixed model was applied for analysis. RESULTS: A fully adjusted mixed model...... of measurements throughout the day showed significant positive relations (p ABP and 0.30 ± 0.04 mmHg (95 % CI 0.22-0.38 mmHg) in diastolic ABP. Correlations between...

  1. Robustness of the Process of Nucleoid Exclusion of Protein Aggregates in Escherichia coli

    Science.gov (United States)

    Neeli-Venkata, Ramakanth; Martikainen, Antti; Gupta, Abhishekh; Gonçalves, Nadia; Fonseca, Jose

    2016-01-01

    ABSTRACT Escherichia coli segregates protein aggregates to the poles by nucleoid exclusion. Combined with cell divisions, this generates heterogeneous aggregate distributions in subsequent cell generations. We studied the robustness of this process with differing medium richness and antibiotics stress, which affect nucleoid size, using multimodal, time-lapse microscopy of live cells expressing both a fluorescently tagged chaperone (IbpA), which identifies in vivo the location of aggregates, and HupA-mCherry, a fluorescent variant of a nucleoid-associated protein. We find that the relative sizes of the nucleoid's major and minor axes change widely, in a positively correlated fashion, with medium richness and antibiotic stress. The aggregate's distribution along the major cell axis also changes between conditions and in agreement with the nucleoid exclusion phenomenon. Consequently, the fraction of aggregates at the midcell region prior to cell division differs between conditions, which will affect the degree of asymmetries in the partitioning of aggregates between cells of future generations. Finally, from the location of the peak of anisotropy in the aggregate displacement distribution, the nucleoid relative size, and the spatiotemporal aggregate distribution, we find that the exclusion of detectable aggregates from midcell is most pronounced in cells with mid-sized nucleoids, which are most common under optimal conditions. We conclude that the aggregate management mechanisms of E. coli are significantly robust but are not immune to stresses due to the tangible effect that these have on nucleoid size. IMPORTANCE Escherichia coli segregates protein aggregates to the poles by nucleoid exclusion. From live single-cell microscopy studies of the robustness of this process to various stresses known to affect nucleoid size, we find that nucleoid size and aggregate preferential locations change concordantly between conditions. Also, the degree of influence of the nucleoid

  2. Dissociable influences of reward motivation and positive emotion on cognitive control.

    Science.gov (United States)

    Chiew, Kimberly S; Braver, Todd S

    2014-06-01

    It is becoming increasingly appreciated that affective and/or motivational influences contribute strongly to goal-oriented cognition and behavior. An unresolved question is whether emotional manipulations (i.e., direct induction of affectively valenced subjective experience) and motivational manipulations (e.g., delivery of performance-contingent rewards and punishments) have similar or distinct effects on cognitive control. Prior work has suggested that reward motivation can reliably enhance a proactive mode of cognitive control, whereas other evidence is suggestive that positive emotion improves cognitive flexibility, but reduces proactive control. However, a limitation of the prior research is that reward motivation and positive emotion have largely been studied independently. Here, we directly compared the effects of positive emotion and reward motivation on cognitive control with a tightly matched, within-subjects design, using the AX-continuous performance task paradigm, which allows for relative measurement of proactive versus reactive cognitive control. High-resolution pupillometry was employed as a secondary measure of cognitive dynamics during task performance. Robust increases in behavioral and pupillometric indices of proactive control were observed with reward motivation. The effects of positive emotion were much weaker, but if anything, also reflected enhancement of proactive control, a pattern that diverges from some prior findings. These results indicate that reward motivation has robust influences on cognitive control, while also highlighting the complexity and heterogeneity of positive-emotion effects. The findings are discussed in terms of potential neurobiological mechanisms.

  3. Model-reference robust tuning of PID controllers

    CERN Document Server

    Alfaro, Victor M

    2016-01-01

    This book presents a unified methodology for the design of PID controllers that encompasses the wide range of different dynamics to be found in industrial processes. This is extended to provide a coherent way of dealing with the tuning of PID controllers. The particular method at the core of the book is the so-called model-reference robust tuning (MoReRT), developed by the authors. MoReRT constitutes a novel and powerful way of thinking of a robust design and taking into account the usual design trade-offs encountered in any control design problem. The book starts by presenting the different two-degree-of-freedom PID control algorithm variations and their conversion relations as well as the indexes used for performance, robustness and fragility evaluation:the bases of the proposed model. Secondly, the MoReRT design methodology and normalized controlled process models and controllers used in the design are described in order to facilitate the formulation of the different design problems and subsequent derivati...

  4. Localization of the relative position of two atoms induced by spontaneous emission

    International Nuclear Information System (INIS)

    Zheng, L.; Li, C.; Li, Y.; Sun, C.P.

    2005-01-01

    We reexamine the back-action of emitted photons on the wave packet evolution about the relative position of two cold atoms. We show that photon recoil resulting from the spontaneous emission can induce the localization of the relative position of the two atoms through the entanglement between the spatial motion of individual atoms and their emitted photons. The obtained result provides a more realistic model for the analysis of the environment-induced localization of a macroscopic object

  5. The positive deviance/hearth approach to reducing child malnutrition: systematic review.

    Science.gov (United States)

    Bisits Bullen, Piroska A

    2011-11-01

    The Positive Deviance/Hearth approach aims to rehabilitate malnourished children using practices from mothers in the community who have well-nourished children despite living in poverty. This study assesses its effectiveness in a range of settings. Systematic review of peer reviewed intervention trials and grey literature evaluation reports of child malnutrition programs using the Positive Deviance/Hearth approach. Ten peer reviewed studies and 14 grey literature reports met the inclusion criteria. These described results for 17 unique Positive Deviance/Hearth programs in 12 countries. Nine programs used a pre- and post-test design without a control, which limited the conclusions that could be drawn. Eight used more robust designs such as non-randomized trials, non-randomized cross-sectional sibling studies and randomized controlled trials (RCTs). Of the eight programs that reported nutritional outcomes, five reported some type of positive result in terms of nutritional status - although the improvement was not always as large as predicted, or across the entire target population. Both the two RCTs demonstrated improvements in carer feeding practices. Qualitative results unanimously reported high levels of satisfaction from participants and recipient communities. Overall this study shows mixed results in terms of program effectiveness, although some Positive Deviance/Hearth programs have clearly been successful in particular settings. Sibling studies suggest that the Positive Deviance/Hearth approach may have a role in preventing malnutrition, not just rehabilitation. Further research is needed using more robust study designs and larger sample sizes. Issues related to community participation and consistency in reporting results need to be addressed. © 2011 Blackwell Publishing Ltd.

  6. Prospective assessment of positioning-related pain in robotic urologic surgery.

    Science.gov (United States)

    Ginsburg, Kevin B; Pape, Kelsey; Heilbronn, Chase; Levin, Michael; Cher, Michael L

    2018-03-01

    This was a prospective study to assess positioning-related pain in 20 awake volunteers in the dorsal lithotomy (DL) and lateral decubitus (LD) positions. Each volunteer was put through the series of discrete, sequential steps used to achieve a final position; each step had two options. The Wong-Baker scale (WB) was used to rate pain for each option and the preferred option and ad lib comments were recorded. We found that awake volunteers could clearly and immediately distinguish differences in pain levels between position options. For the DL position, volunteers favored having the arms slightly flexed and pronated as opposed to being straight and supinated reflected by statistically less painful WB scores and option preference. Volunteers preferred having the neck flexed as opposed to being flat. For the LD position, volunteers reported statistically lower pain scores and preference for a foam roll for axilla support as opposed to a rolled blanket, the table flexed without the kidney rest as opposed to a raised kidney rest, and the over arm board as oppose to stacked blankets for contralateral arm support. Ad lib comments from the volunteers supported the above findings. To our knowledge, ours is the first study to demonstrate objective preferences for variations in surgical positioning using awake volunteers. This exercise with awake volunteers resulted in immediate changes in positioning for real robotic surgery patients in our practice.

  7. Robust Covariance Estimators Based on Information Divergences and Riemannian Manifold

    Directory of Open Access Journals (Sweden)

    Xiaoqiang Hua

    2018-03-01

    Full Text Available This paper proposes a class of covariance estimators based on information divergences in heterogeneous environments. In particular, the problem of covariance estimation is reformulated on the Riemannian manifold of Hermitian positive-definite (HPD matrices. The means associated with information divergences are derived and used as the estimators. Without resorting to the complete knowledge of the probability distribution of the sample data, the geometry of the Riemannian manifold of HPD matrices is considered in mean estimators. Moreover, the robustness of mean estimators is analyzed using the influence function. Simulation results indicate the robustness and superiority of an adaptive normalized matched filter with our proposed estimators compared with the existing alternatives.

  8. Robust indexing for automatic data collection

    International Nuclear Information System (INIS)

    Sauter, Nicholas K.; Grosse-Kunstleve, Ralf W.; Adams, Paul D.

    2003-01-01

    We present improved methods for indexing diffraction patterns from macromolecular crystals. The novel procedures include a more robust way to verify the position of the incident X-ray beam on the detector, an algorithm to verify that the deduced lattice basis is consistent with the observations, and an alternative approach to identify the metric symmetry of the lattice. These methods help to correct failures commonly experienced during indexing, and increase the overall success rate of the process. Rapid indexing, without the need for visual inspection, will play an important role as beamlines at synchrotron sources prepare for high-throughput automation

  9. A Robust Measure of Investor Contrarian Behaviour

    Science.gov (United States)

    Challet, Damien; Morton de Lachapelle, David

    Using the transaction history of all the clients of an on-line broker, we analyse the daily aggregated investment fluxes of individual investors, companies, and asset managers. Computing the probability that price returns and daily investment fluxes have the same sign provides a robust characterisation of contrarian behaviour. The three categories are found to be contrarian, but with widely different intensities. Individual investors are by far the most contrarian of the three, followed by companies. Asset managers are only mildly contrarian with respect positive price returns.

  10. International Conference on Robust Statistics

    CERN Document Server

    Filzmoser, Peter; Gather, Ursula; Rousseeuw, Peter

    2003-01-01

    Aspects of Robust Statistics are important in many areas. Based on the International Conference on Robust Statistics 2001 (ICORS 2001) in Vorau, Austria, this volume discusses future directions of the discipline, bringing together leading scientists, experienced researchers and practitioners, as well as younger researchers. The papers cover a multitude of different aspects of Robust Statistics. For instance, the fundamental problem of data summary (weights of evidence) is considered and its robustness properties are studied. Further theoretical subjects include e.g.: robust methods for skewness, time series, longitudinal data, multivariate methods, and tests. Some papers deal with computational aspects and algorithms. Finally, the aspects of application and programming tools complete the volume.

  11. Including robustness in multi-criteria optimization for intensity-modulated proton therapy

    Science.gov (United States)

    Chen, Wei; Unkelbach, Jan; Trofimov, Alexei; Madden, Thomas; Kooy, Hanne; Bortfeld, Thomas; Craft, David

    2012-02-01

    We present a method to include robustness in a multi-criteria optimization (MCO) framework for intensity-modulated proton therapy (IMPT). The approach allows one to simultaneously explore the trade-off between different objectives as well as the trade-off between robustness and nominal plan quality. In MCO, a database of plans each emphasizing different treatment planning objectives, is pre-computed to approximate the Pareto surface. An IMPT treatment plan that strikes the best balance between the different objectives can be selected by navigating on the Pareto surface. In our approach, robustness is integrated into MCO by adding robustified objectives and constraints to the MCO problem. Uncertainties (or errors) of the robust problem are modeled by pre-calculated dose-influence matrices for a nominal scenario and a number of pre-defined error scenarios (shifted patient positions, proton beam undershoot and overshoot). Objectives and constraints can be defined for the nominal scenario, thus characterizing nominal plan quality. A robustified objective represents the worst objective function value that can be realized for any of the error scenarios and thus provides a measure of plan robustness. The optimization method is based on a linear projection solver and is capable of handling large problem sizes resulting from a fine dose grid resolution, many scenarios, and a large number of proton pencil beams. A base-of-skull case is used to demonstrate the robust optimization method. It is demonstrated that the robust optimization method reduces the sensitivity of the treatment plan to setup and range errors to a degree that is not achieved by a safety margin approach. A chordoma case is analyzed in more detail to demonstrate the involved trade-offs between target underdose and brainstem sparing as well as robustness and nominal plan quality. The latter illustrates the advantage of MCO in the context of robust planning. For all cases examined, the robust optimization for

  12. Robust Ensemble Filtering and Its Relation to Covariance Inflation in the Ensemble Kalman Filter

    KAUST Repository

    Luo, Xiaodong; Hoteit, Ibrahim

    2011-01-01

    A robust ensemble filtering scheme based on the H∞ filtering theory is proposed. The optimal H∞ filter is derived by minimizing the supremum (or maximum) of a predefined cost function, a criterion different from the minimum variance used

  13. Development of robust flexible OLED encapsulations using simulated estimations and experimental validations

    International Nuclear Information System (INIS)

    Lee, Chang-Chun; Shih, Yan-Shin; Wu, Chih-Sheng; Tsai, Chia-Hao; Yeh, Shu-Tang; Peng, Yi-Hao; Chen, Kuang-Jung

    2012-01-01

    This work analyses the overall stress/strain characteristic of flexible encapsulations with organic light-emitting diode (OLED) devices. A robust methodology composed of a mechanical model of multi-thin film under bending loads and related stress simulations based on nonlinear finite element analysis (FEA) is proposed, and validated to be more reliable compared with related experimental data. With various geometrical combinations of cover plate, stacked thin films and plastic substrate, the position of the neutral axis (NA) plate, which is regarded as a key design parameter to minimize stress impact for the concerned OLED devices, is acquired using the present methodology. The results point out that both the thickness and mechanical properties of the cover plate help in determining the NA location. In addition, several concave and convex radii are applied to examine the reliable mechanical tolerance and to provide an insight into the estimated reliability of foldable OLED encapsulations. (paper)

  14. Off-Line Robust Constrained MPC for Linear Time-Varying Systems with Persistent Disturbances

    Directory of Open Access Journals (Sweden)

    P. Bumroongsri

    2014-01-01

    Full Text Available An off-line robust constrained model predictive control (MPC algorithm for linear time-varying (LTV systems is developed. A novel feature is the fact that both model uncertainty and bounded additive disturbance are explicitly taken into account in the off-line formulation of MPC. In order to reduce the on-line computational burdens, a sequence of explicit control laws corresponding to a sequence of positively invariant sets is computed off-line. At each sampling time, the smallest positively invariant set containing the measured state is determined and the corresponding control law is implemented in the process. The proposed MPC algorithm can guarantee robust stability while ensuring the satisfaction of input and output constraints. The effectiveness of the proposed MPC algorithm is illustrated by two examples.

  15. Robust Scientists

    DEFF Research Database (Denmark)

    Gorm Hansen, Birgitte

    their core i nterests, 2) developing a selfsupply of industry interests by becoming entrepreneurs and thus creating their own compliant industry partner and 3) balancing resources within a larger collective of researchers, thus countering changes in the influx of funding caused by shifts in political...... knowledge", Danish research policy seems to have helped develop politically and economically "robust scientists". Scientific robustness is acquired by way of three strategies: 1) tasting and discriminating between resources so as to avoid funding that erodes academic profiles and push scientists away from...

  16. Resilience and positive affect contribute to lower cancer-related fatigue among Chinese patients with gastric cancer.

    Science.gov (United States)

    Zou, Guiyuan; Li, Ye; Xu, Ruicai; Li, Ping

    2018-04-01

    To investigate the prevalence of cancer-related fatigue and explore the relationship between resilience, positive affect, and fatigue among Chinese patients with gastric cancer. Cancer-related fatigue is the most distressing symptom reported frequently by cancer patients during both treatment and survival phases. Resilience and positive affect as vital protective factors against cancer-related fatigue have been examined, but the underlying psychological mechanisms are not well understood. A cross-sectional study. Two hundred and three gastric cancer patients were enrolled from three hospitals in China. The Cancer Fatigue Scale, the positive affect subscale of the Positive and Negative Affect Schedule and the Connor-Davidson Resilience Scale (CD-RISC10) were administered. Hierarchical linear regression modelling was conducted to examine the association between resilience and cancer-related fatigue, and the mediating effect of positive affect. The incidence of clinically relevant fatigue among patients with gastric cancer was 91.6%. Regression analysis showed that resilience was negatively associated with cancer-related fatigue, explaining 15.4% of variance in cancer-related fatigue. Mediation analysis showed that high resilience was associated with increased positive affect, which was associated with decreased cancer-related fatigue. Cancer-related fatigue is prevalent among patients with gastric cancer. Positive affect may mediate the relationship between resilience and cancer-related fatigue. Interventions that attend to resilience training and promotion of positive affect may be the focus for future clinical and research endeavours. © 2017 John Wiley & Sons Ltd.

  17. Application of Adaptive Sliding Mode Position Controller with PI ...

    African Journals Online (AJOL)

    PISMC) techniques for controlling the rotor position of PMDC motor drive system. In particular, since SMC is robust in the presence of the matched uncertainties and external disturbances, the desired position is perfectly tracked. In addition, the ...

  18. Robust Trust in Expert Testimony

    Directory of Open Access Journals (Sweden)

    Christian Dahlman

    2015-05-01

    Full Text Available The standard of proof in criminal trials should require that the evidence presented by the prosecution is robust. This requirement of robustness says that it must be unlikely that additional information would change the probability that the defendant is guilty. Robustness is difficult for a judge to estimate, as it requires the judge to assess the possible effect of information that the he or she does not have. This article is concerned with expert witnesses and proposes a method for reviewing the robustness of expert testimony. According to the proposed method, the robustness of expert testimony is estimated with regard to competence, motivation, external strength, internal strength and relevance. The danger of trusting non-robust expert testimony is illustrated with an analysis of the Thomas Quick Case, a Swedish legal scandal where a patient at a mental institution was wrongfully convicted for eight murders.

  19. Robust domain decomposition preconditioners for abstract symmetric positive definite bilinear forms

    KAUST Repository

    Efendiev, Yalchin; Galvis, Juan; Lazarov, Raytcho; Willems, Joerg

    2012-01-01

    An abstract framework for constructing stable decompositions of the spaces corresponding to general symmetric positive definite problems into "local" subspaces and a global "coarse" space is developed. Particular applications of this abstract

  20. Reliability and Robustness Evaluation of Timber Structures

    DEFF Research Database (Denmark)

    Cizmar, Dean; Sørensen, John Dalsgaard; Kirkegaard, Poul Henning

    In the last few decades there have been intensely research concerning reliability of timber structures. This is primarily because there is an increased focus on society on sustainability and environmental aspects. Modern timber as a building material is also being competitive compared to concrete...... and steel. However, reliability models applied to timber were always related to individual components but not the systems. as any real structure is a complex system, system behaviour must be of a particular interest. In the chapter 1 of this document an overview of stochastic models for strength and loads...... (deterministic, probabilistic and risk based approaches) of the robustness are given. Chapter 3 deals more detailed with the robustness of timber structures....

  1. Robustness in econometrics

    CERN Document Server

    Sriboonchitta, Songsak; Huynh, Van-Nam

    2017-01-01

    This book presents recent research on robustness in econometrics. Robust data processing techniques – i.e., techniques that yield results minimally affected by outliers – and their applications to real-life economic and financial situations are the main focus of this book. The book also discusses applications of more traditional statistical techniques to econometric problems. Econometrics is a branch of economics that uses mathematical (especially statistical) methods to analyze economic systems, to forecast economic and financial dynamics, and to develop strategies for achieving desirable economic performance. In day-by-day data, we often encounter outliers that do not reflect the long-term economic trends, e.g., unexpected and abrupt fluctuations. As such, it is important to develop robust data processing techniques that can accommodate these fluctuations.

  2. Robust Programming by Example

    OpenAIRE

    Bishop , Matt; Elliott , Chip

    2011-01-01

    Part 2: WISE 7; International audience; Robust programming lies at the heart of the type of coding called “secure programming”. Yet it is rarely taught in academia. More commonly, the focus is on how to avoid creating well-known vulnerabilities. While important, that misses the point: a well-structured, robust program should anticipate where problems might arise and compensate for them. This paper discusses one view of robust programming and gives an example of how it may be taught.

  3. Robust Reliability or reliable robustness? - Integrated consideration of robustness and reliability aspects

    DEFF Research Database (Denmark)

    Kemmler, S.; Eifler, Tobias; Bertsche, B.

    2015-01-01

    products are and vice versa. For a comprehensive understanding and to use existing synergies between both domains, this paper discusses the basic principles of Reliability- and Robust Design theory. The development of a comprehensive model will enable an integrated consideration of both domains...

  4. Robust PID Controller for a Pneumatic Actuator

    Directory of Open Access Journals (Sweden)

    Skarpetis Michael G.

    2016-01-01

    Full Text Available In this paper the position control pneumatic actuator using a robust PID controller is presented. The parameters of the PID controller are computed using a Hurwitz invariability technique enriched with a Simulated Annealing Algorithm. The nonlinear model involves uncertain parameters due to linearization of the servo valve, variations of the initial volume of the cylinder and variation of the external load. The problem is proven to be solvable and the controller parameters are chosen to provide a suboptimal solution for tracking error minimization. Simulation results are presented for the nonlinear model.

  5. Robust Synchronization in an E/I Network with Medium Synaptic Delay and High Level of Heterogeneity

    International Nuclear Information System (INIS)

    Han Fang; Wang Zhi-Jie; Gong Tao; Fan Hong

    2015-01-01

    It is known that both excitatory and inhibitory neuronal networks can achieve robust synchronization only under certain conditions, such as long synaptic delay or low level of heterogeneity. In this work, robust synchronization can be found in an excitatory/inhibitory (E/I) neuronal network with medium synaptic delay and high level of heterogeneity, which often occurs in real neuronal networks. Two effects of post-synaptic potentials (PSP) to network synchronization are presented, and the synaptic contribution of excitatory and inhibitory neurons to robust synchronization in this E/I network is investigated. It is found that both excitatory and inhibitory neurons may contribute to robust synchronization in E/I networks, especially the excitatory PSP has a more positive effect on synchronization in E/I networks than that in excitatory networks. This may explain the strong robustness of synchronization in E/I neuronal networks. (paper)

  6. SU-E-J-137: Incorporating Tumor Regression Into Robust Plan Optimization for Head and Neck Radiotherapy

    International Nuclear Information System (INIS)

    Zhang, P; Hu, J; Tyagi, N; Mageras, G; Lee, N; Hunt, M

    2014-01-01

    Purpose: To develop a robust planning paradigm which incorporates a tumor regression model into the optimization process to ensure tumor coverage in head and neck radiotherapy. Methods: Simulation and weekly MR images were acquired for a group of head and neck patients to characterize tumor regression during radiotherapy. For each patient, the tumor and parotid glands were segmented on the MR images and the weekly changes were formulated with an affine transformation, where morphological shrinkage and positional changes are modeled by a scaling factor, and centroid shifts, respectively. The tumor and parotid contours were also transferred to the planning CT via rigid registration. To perform the robust planning, weekly predicted PTV and parotid structures were created by transforming the corresponding simulation structures according to the weekly affine transformation matrix averaged over patients other than him/herself. Next, robust PTV and parotid structures were generated as the union of the simulation and weekly prediction contours. In the subsequent robust optimization process, attainment of the clinical dose objectives was required for the robust PTV and parotids, as well as other organs at risk (OAR). The resulting robust plans were evaluated by looking at the weekly and total accumulated dose to the actual weekly PTV and parotid structures. The robust plan was compared with the original plan based on the planning CT to determine its potential clinical benefit. Results: For four patients, the average weekly change to tumor volume and position was −4% and 1.2 mm laterally-posteriorly. Due to these temporal changes, the robust plans resulted in an accumulated PTV D95 that was, on average, 2.7 Gy higher than the plan created from the planning CT. OAR doses were similar. Conclusion: Integration of a tumor regression model into target delineation and plan robust optimization is feasible and may yield improved tumor coverage. Part of this research is supported

  7. Smartphone-Based Indoor Integrated WiFi/MEMS Positioning Algorithm in a Multi-Floor Environment

    Directory of Open Access Journals (Sweden)

    Zengshan Tian

    2015-03-01

    Full Text Available Indoor positioning in a multi-floor environment by using a smartphone is considered in this paper. The positioning accuracy and robustness of WiFi fingerprinting-based positioning are limited due to the unexpected variation of WiFi measurements between floors. On this basis, we propose a novel smartphone-based integrated WiFi/MEMS positioning algorithm based on the robust extended Kalman filter (EKF. The proposed algorithm first relies on the gait detection approach and quaternion algorithm to estimate the velocity and heading angles of the target. Second, the velocity and heading angles, together with the results of WiFi fingerprinting-based positioning, are considered as the input of the robust EKF for the sake of conducting two-dimensional (2D positioning. Third, the proposed algorithm calculates the height of the target by using the real-time recorded barometer and geographic data. Finally, the experimental results show that the proposed algorithm achieves the positioning accuracy with root mean square errors (RMSEs less than 1 m in an actual multi-floor environment.

  8. A kriging metamodel-assisted robust optimization method based on a reverse model

    Science.gov (United States)

    Zhou, Hui; Zhou, Qi; Liu, Congwei; Zhou, Taotao

    2018-02-01

    The goal of robust optimization methods is to obtain a solution that is both optimum and relatively insensitive to uncertainty factors. Most existing robust optimization approaches use outer-inner nested optimization structures where a large amount of computational effort is required because the robustness of each candidate solution delivered from the outer level should be evaluated in the inner level. In this article, a kriging metamodel-assisted robust optimization method based on a reverse model (K-RMRO) is first proposed, in which the nested optimization structure is reduced into a single-loop optimization structure to ease the computational burden. Ignoring the interpolation uncertainties from kriging, K-RMRO may yield non-robust optima. Hence, an improved kriging-assisted robust optimization method based on a reverse model (IK-RMRO) is presented to take the interpolation uncertainty of kriging metamodel into consideration. In IK-RMRO, an objective switching criterion is introduced to determine whether the inner level robust optimization or the kriging metamodel replacement should be used to evaluate the robustness of design alternatives. The proposed criterion is developed according to whether or not the robust status of the individual can be changed because of the interpolation uncertainties from the kriging metamodel. Numerical and engineering cases are used to demonstrate the applicability and efficiency of the proposed approach.

  9. Diode readout electronics for beam intensity and position monitors for FELs

    International Nuclear Information System (INIS)

    Herrmann, S; Hart, P; Freytag, M; Pines, J; Weaver, M; Sapozhnikov, L; Nelson, S; Koglin, J; Carini, G A; Tomada, A; Haller, G

    2014-01-01

    LCLS uses Intensity-Position Monitors (IPM) to measure intensity and position of the FEL x-ray pulses. The primary beam passes through a silicon nitride film and four diodes, arranged in quadrants, detect the backscattered x-ray photons. The position is derived from the relative intensity of the four diodes, while the sum provides beam intensity information. In contrast to traditional synchrotron beam monitors, where diodes measure a DC current signal, the LCLS beam monitors have to cope with the pulsed nature of the FEL, which requires a large single shot dynamic range. A key component of these beam monitors is the readout electronics. The first generation of beam monitors showed some limitations. A new scheme with upgraded electronics, firmware and software was implemented resulting in a more robust and reliable measuring tool.

  10. Robustness of muscle synergies during visuomotor adaptation

    Directory of Open Access Journals (Sweden)

    Reinhard eGentner

    2013-09-01

    Full Text Available During visuomotor adaptation a novel mapping between visual targets and motor commands is gradually acquired. How muscle activation patterns are affected by this process is an open question. We tested whether the structure of muscle synergies is preserved during adaptation to a visuomotor rotation. Eight subjects applied targeted isometric forces on a handle instrumented with a force transducer while electromyographic (EMG activity was recorded from 13 shoulder and elbow muscles. The recorded forces were mapped into horizontal displacements of a virtual sphere with simulated mass, elasticity, and damping. The task consisted of moving the sphere to a target at one of eight equally spaced directions. Subjects performed three baseline blocks of 32 trials, followed by six blocks with a 45° CW rotation applied to the planar force, and finally three wash-out blocks without the perturbation. The sphere position at 100 ms after movement onset revealed significant directional error at the beginning of the rotation, a gradual learning in subsequent blocks, and aftereffects at the beginning of the wash-out. The change in initial force direction was closely related to the change in directional tuning of the initial EMG activity of most muscles. Throughout the experiment muscle synergies extracted using a non-negative matrix factorization algorithm from the muscle patterns recorded during the baseline blocks could reconstruct the muscle patterns of all other blocks with an accuracy significantly higher than chance indicating structural robustness. In addition, the synergies extracted from individual blocks remained similar to the baseline synergies throughout the experiment. Thus synergy structure is robust during visuomotor adaptation suggesting that changes in muscle patterns are obtained by rotating the directional tuning of the synergy recruitment.

  11. A new robust control for minirotorcraft unmanned aerial vehicles.

    Science.gov (United States)

    Mokhtari, M Rida; Cherki, Brahim

    2015-05-01

    This paper presents a new robust control based on finite-time Lyapunov stability controller and proved with backstepping method for the position and the attitude of a small rotorcraft unmanned aerial vehicle subjected to bounded uncertainties and disturbances. The dynamical motion equations are obtained by the Newton-Euler formalism. The proposed controller combines the advantage of the backstepping approach with finite-time convergence techniques to generate a control laws to guarantee the faster convergence of the state variables to their desired values in short time and compensate for the bounded disturbances. A formal proof of the closed-loop stability and finite-time convergence of tracking errors is derived using the Lyapunov function technique. Simulation results are presented to corroborate the effectiveness and the robustness of the proposed control method. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  12. Anti-Windup Scheme for Practical Control of Positioning Systems

    Directory of Open Access Journals (Sweden)

    Wahyudi Tarig Faisal and Abdulgani Albagul

    2012-10-01

    Full Text Available Positioning systems generally need a good controller to achieve high accuracy, fast response and robustness. In addition, ease of controller design and simplicity of controller structure are very important for practical application.  For satisfying these requirements, nominal characteristic trajectory following controller (NCTF has been proposed as a practical point-to-point (PTP positioning control. However, the effect of actuator saturation can not be completely compensated for due to the integrator windup as the plant parameters vary. This paper presents a method to improve the NCTF controller for overcoming the problem of integrator windup using simple and classical tracking anti-windup scheme. The improved NCTF controller is evaluated through simulation using a rotary positioning system. The results show that the improved NCTF controller is adequate to compensate for the effect of integrator windup. Keywords: Positioning, point-to-point, integrator windup, compensation, controller, robustness.

  13. Analytic robust stability analysis of SVD orbit feedback

    CERN Document Server

    Pfingstner, Jürgen

    2012-01-01

    Orbit feedback controllers are indispensable for the operation of modern particle accelerators. Many such controllers are based on the decoupling of the inputs and outputs of the system to be controlled with the help of the singular value decomposition (SVD controller). It is crucial to verify the stability of SVD controllers, also in the presence of mismatches between the used accelerator model and the real machine (robust stability problem). In this paper, analytical criteria for guaranteed stability margins of SVD orbit feedback systems for three different types of model mismatches are presented: scaling errors of actuators and BPMs (beam position monitors) and additive errors of the orbit response matrix. For the derivation of these criteria, techniques from robust control theory have been used, e.g the small gain theorem. The obtained criteria can be easily applied directly to other SVD orbit feedback systems. As an example, the criteria were applied to the orbit feedback system of the Compact Linear ...

  14. Promoting a Positive Image: Public Relations Strategies for Special Educators.

    Science.gov (United States)

    Brennan, Kathleen B.; Miller, April D.; Brennan, J. Patrick, II

    2000-01-01

    A positive public relations campaign specific to special education can stimulate teacher cooperation and principal support, improve community perceptions of special education students, and increase hiring of special education students by local businesses. A monthly calendar of suggested activities and guidelines for starting a public relations…

  15. A Framework to Analyze the Robustness of Social-ecological Systems from an Institutional Perspective

    Directory of Open Access Journals (Sweden)

    John M. Anderies

    2004-06-01

    Full Text Available What makes social-ecological systems (SESs robust? In this paper, we look at the institutional configurations that affect the interactions among resources, resource users, public infrastructure providers, and public infrastructures. We propose a framework that helps identify potential vulnerabilities of SESs to disturbances. All the links between components of this framework can fail and thereby reduce the robustness of the system. We posit that the link between resource users and public infrastructure providers is a key variable affecting the robustness of SESs that has frequently been ignored in the past. We illustrate the problems caused by a disruption in this link. We then briefly describe the design principles originally developed for robust common-pool resource institutions, because they appear to be a good starting point for the development of design principles for more general SESs and do include the link between resource users and public infrastructure providers.

  16. Robust power system frequency control

    CERN Document Server

    Bevrani, Hassan

    2014-01-01

    This updated edition of the industry standard reference on power system frequency control provides practical, systematic and flexible algorithms for regulating load frequency, offering new solutions to the technical challenges introduced by the escalating role of distributed generation and renewable energy sources in smart electric grids. The author emphasizes the physical constraints and practical engineering issues related to frequency in a deregulated environment, while fostering a conceptual understanding of frequency regulation and robust control techniques. The resulting control strategi

  17. Characterizing Positive and Negative Emotional Experiences in Young Adults With Borderline Personality Disorder Symptoms.

    Science.gov (United States)

    Chu, Carol; Victor, Sarah E; Klonsky, E David

    2016-09-01

    Some researchers suggest that borderline personality disorder (BPD) is characterized by elevated negative emotion; others argue that BPD involves both reduced positive and increased negative emotion. This study characterizes the emotional experiences of individuals with BPD symptoms in a combined university and community sample. Participants (N = 150) completed a clinical interview assessing BPD symptoms and self-report measures of positive and negative emotion. A subset (n = 106) completed a measure of emotion daily for 2 weeks. Pearson's correlations and multilevel modeling were used to examine the cross-sectional and longitudinal relationships between BPD symptoms and emotions. BPD symptoms were robustly related to increased negative emotion; this relationship remained after accounting for positive emotion. BPD symptoms were weakly related to decreased positive emotion; this relationship was no longer significant after accounting for negative emotion. BPD symptoms predicted higher levels of negative and not positive emotion over 14 days. These patterns held for subscales assessing intensity, frequency, and duration of negative and positive emotions. Findings suggest that individuals with BPD features are chiefly distinguished by elevated negative emotional experience. © 2016 Wiley Periodicals, Inc.

  18. Robust

    DEFF Research Database (Denmark)

    2017-01-01

    Robust – Reflections on Resilient Architecture’, is a scientific publication following the conference of the same name in November of 2017. Researches and PhD-Fellows, associated with the Masters programme: Cultural Heritage, Transformation and Restoration (Transformation), at The Royal Danish...

  19. Child Temperamental Flexibility Moderates the Relation between Positive Parenting and Adolescent Adjustment

    Science.gov (United States)

    Rabinowitz, Jill A.; Drabick, Deborah A.G.; Reynolds, Maureen D.; Clark, Duncan B.; Olino, Thomas M.

    2016-01-01

    Temperamental flexibility and lower positive parenting are associated with internalizing and externalizing problems; however, youth varying in flexibility may be differentially affected by positive parenting in the prediction of symptoms. We examined whether children's flexibility moderated prospective relations between maternal and paternal positive parenting and youth internalizing and externalizing symptoms during adolescence. Participants (N =775, 71% male) and their caregivers completed measures when youth were 10-12 and 12-14 years old. Father positive parenting interacted with child flexibility to predict father-reported internalizing and externalizing problems. Consistent with the diathesis-stress model, children lower in flexibility experienced greater symptoms than children higher in flexibility in lower positive parenting contexts. Among children lower in flexibility, lower paternal positive parenting was associated with greater internalizing and externalizing symptoms compared to higher paternal positive parenting. However, among youth higher in flexibility, symptom levels were similar regardless of whether youth experienced lower or higher paternal positive parenting. PMID:26834305

  20. Strategies to prevent positioning-related complications associated with the lateral suboccipital approach.

    Science.gov (United States)

    Furuno, Yuichi; Sasajima, Hiroyasu; Goto, Yukihiro; Taniyama, Ichita; Aita, Kazuyasu; Owada, Kei; Tatsuzawa, Kazunori; Mineura, Katsuyoshi

    2014-02-01

    The lateral positioning used for the lateral suboccipital surgical approach is associated with various pathophysiologic complications. Strategies to avoid complications including an excessive load on the cervical vertebra and countermeasures against pressure ulcer development are needed. We retrospectively investigated positioning-related complications in 71 patients with cerebellopontine angle lesions undergoing surgery in our department between January 2003 and December 2010 using the lateral suboccipital approach. One patient postoperatively developed rhabdomyolysis, and another presented with transient peroneal nerve palsy on the unaffected side. Stage I and II pressure ulcers were noted in 22 and 12 patients, respectively, although neither stage III nor more severe pressure ulcers occurred. No patients experienced cervical vertebra and spinal cord impairments, brachial plexus palsy, or ulnar nerve palsy associated with rotation and flexion of the neck. Strategies to prevent positioning-related complications, associated with lateral positioning for the lateral suboccipital surgical approach, include the following: atraumatic fixation of the neck focusing on jugular venous perfusion and airway pressure, trunk rotation, and sufficient relief of weightbearing and protection of nerves including the peripheral nerves of all four extremities.

  1. Robustness in Railway Operations (RobustRailS)

    DEFF Research Database (Denmark)

    Jensen, Jens Parbo; Nielsen, Otto Anker

    This study considers the problem of enhancing railway timetable robustness without adding slack time, hence increasing the travel time. The approach integrates a transit assignment model to assess how passengers adapt their behaviour whenever operations are changed. First, the approach considers...

  2. Robust Proton Pencil Beam Scanning Treatment Planning for Rectal Cancer Radiation Therapy

    International Nuclear Information System (INIS)

    Blanco Kiely, Janid Patricia; White, Benjamin M.

    2016-01-01

    Purpose: To investigate, in a treatment plan design and robustness study, whether proton pencil beam scanning (PBS) has the potential to offer advantages, relative to interfraction uncertainties, over photon volumetric modulated arc therapy (VMAT) in a locally advanced rectal cancer patient population. Methods and Materials: Ten patients received a planning CT scan, followed by an average of 4 weekly offline CT verification CT scans, which were rigidly co-registered to the planning CT. Clinical PBS plans were generated on the planning CT, using a single-field uniform-dose technique with single-posterior and parallel-opposed (LAT) fields geometries. The VMAT plans were generated on the planning CT using 2 6-MV, 220° coplanar arcs. Clinical plans were forward-calculated on verification CTs to assess robustness relative to anatomic changes. Setup errors were assessed by forward-calculating clinical plans with a ±5-mm (left–right, anterior–posterior, superior–inferior) isocenter shift on the planning CT. Differences in clinical target volume and organ at risk dose–volume histogram (DHV) indicators between plans were tested for significance using an appropriate Wilcoxon test (P<.05). Results: Dosimetrically, PBS plans were statistically different from VMAT plans, showing greater organ at risk sparing. However, the bladder was statistically identical among LAT and VMAT plans. The clinical target volume coverage was statistically identical among all plans. The robustness test found that all DVH indicators for PBS and VMAT plans were robust, except the LAT's genitalia (V5, V35). The verification CT plans showed that all DVH indicators were robust. Conclusions: Pencil beam scanning plans were found to be as robust as VMAT plans relative to interfractional changes during treatment when posterior beam angles and appropriate range margins are used. Pencil beam scanning dosimetric gains in the bowel (V15, V20) over VMAT suggest that using PBS to treat rectal cancer

  3. Robust Proton Pencil Beam Scanning Treatment Planning for Rectal Cancer Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Blanco Kiely, Janid Patricia, E-mail: jkiely@sas.upenn.edu; White, Benjamin M.

    2016-05-01

    Purpose: To investigate, in a treatment plan design and robustness study, whether proton pencil beam scanning (PBS) has the potential to offer advantages, relative to interfraction uncertainties, over photon volumetric modulated arc therapy (VMAT) in a locally advanced rectal cancer patient population. Methods and Materials: Ten patients received a planning CT scan, followed by an average of 4 weekly offline CT verification CT scans, which were rigidly co-registered to the planning CT. Clinical PBS plans were generated on the planning CT, using a single-field uniform-dose technique with single-posterior and parallel-opposed (LAT) fields geometries. The VMAT plans were generated on the planning CT using 2 6-MV, 220° coplanar arcs. Clinical plans were forward-calculated on verification CTs to assess robustness relative to anatomic changes. Setup errors were assessed by forward-calculating clinical plans with a ±5-mm (left–right, anterior–posterior, superior–inferior) isocenter shift on the planning CT. Differences in clinical target volume and organ at risk dose–volume histogram (DHV) indicators between plans were tested for significance using an appropriate Wilcoxon test (P<.05). Results: Dosimetrically, PBS plans were statistically different from VMAT plans, showing greater organ at risk sparing. However, the bladder was statistically identical among LAT and VMAT plans. The clinical target volume coverage was statistically identical among all plans. The robustness test found that all DVH indicators for PBS and VMAT plans were robust, except the LAT's genitalia (V5, V35). The verification CT plans showed that all DVH indicators were robust. Conclusions: Pencil beam scanning plans were found to be as robust as VMAT plans relative to interfractional changes during treatment when posterior beam angles and appropriate range margins are used. Pencil beam scanning dosimetric gains in the bowel (V15, V20) over VMAT suggest that using PBS to treat rectal

  4. Robustness against parametric noise of nonideal holonomic gates

    International Nuclear Information System (INIS)

    Lupo, Cosmo; Aniello, Paolo; Napolitano, Mario; Florio, Giuseppe

    2007-01-01

    Holonomic gates for quantum computation are commonly considered to be robust against certain kinds of parametric noise, the cause of this robustness being the geometric character of the transformation achieved in the adiabatic limit. On the other hand, the effects of decoherence are expected to become more and more relevant when the adiabatic limit is approached. Starting from the system described by Florio et al. [Phys. Rev. A 73, 022327 (2006)], here we discuss the behavior of nonideal holonomic gates at finite operational time, i.e., long before the adiabatic limit is reached. We have considered several models of parametric noise and studied the robustness of finite-time gates. The results obtained suggest that the finite-time gates present some effects of cancellation of the perturbations introduced by the noise which mimic the geometrical cancellation effect of standard holonomic gates. Nevertheless, a careful analysis of the results leads to the conclusion that these effects are related to a dynamical instead of a geometrical feature

  5. Robustness against parametric noise of nonideal holonomic gates

    Science.gov (United States)

    Lupo, Cosmo; Aniello, Paolo; Napolitano, Mario; Florio, Giuseppe

    2007-07-01

    Holonomic gates for quantum computation are commonly considered to be robust against certain kinds of parametric noise, the cause of this robustness being the geometric character of the transformation achieved in the adiabatic limit. On the other hand, the effects of decoherence are expected to become more and more relevant when the adiabatic limit is approached. Starting from the system described by Florio [Phys. Rev. A 73, 022327 (2006)], here we discuss the behavior of nonideal holonomic gates at finite operational time, i.e., long before the adiabatic limit is reached. We have considered several models of parametric noise and studied the robustness of finite-time gates. The results obtained suggest that the finite-time gates present some effects of cancellation of the perturbations introduced by the noise which mimic the geometrical cancellation effect of standard holonomic gates. Nevertheless, a careful analysis of the results leads to the conclusion that these effects are related to a dynamical instead of a geometrical feature.

  6. HIV-positive patients’ and their families’ comprehension of HIV- and AIDS-related information

    Directory of Open Access Journals (Sweden)

    Gedina E. de Wet

    2013-04-01

    Full Text Available Despite acknowledgement of the importance of sharing HIV- and AIDS-related information with people living with HIV, it is still unclear as to what their actual comprehension is of this information. This research was part of a larger project, Tswaragano, conducted in the North-West Province, South Africa, which explored and described the competence, ability and strengths of the family of the HIV-positive patient during home support. This research focused on Potchefstroom in the North-West Province. This article focuses on research with the objective being to explore and describe the comprehension of HIV-positive patients and their families with regard to HIV- and AIDS-related information, and to formulate recommendations to improve their comprehension of this information. A quantitative, explorative and descriptive survey design was followed. Data were collected by means of questionnaires completed by HIV-positive patients (n = 79 and their family members (n = 34. Descriptive statistical analysis by means of frequency analysis was conducted. Ethical considerations and mechanisms to enhance validity and reliability are discussed. The results indicated that both HIV-positive respondents and their families face social and financial challenges due to unemployment and low income. A strength found in this research is that the majority of respondents are linked to a church, which can be a valuable platform to share information on HIV and AIDS. With regards to sharing, sources and comprehension of HIV- and AIDS-related information, it is apparent that respondents perceived that pre- and post-counselling provided an opportunity for information sharing, but that they need health care workers to spend more time with them, to be non-judgemental and to make more use of visual aids. It furthermore seems that the majority of HIV-positive respondents in this study did comprehend the need for and negotiate for safer sexual practices. It was concluded that

  7. HIV-positive patients’ and their families’ comprehension of HIV- and AIDS-related information

    Directory of Open Access Journals (Sweden)

    Gedina E. de Wet

    2013-04-01

    Full Text Available Despite acknowledgement of the importance of sharing HIV- and AIDS-related information with people living with HIV, it is still unclear as to what their actual comprehension is of this information. This research was part of a larger project, Tswaragano, conducted in the North-West Province, South Africa, which explored and described the competence, ability and strengths of the family of the HIV-positive patient during home support. This research focused on Potchefstroom in the North-West Province. This article focuses on research with the objective being to explore and describe the comprehension of HIV-positive patients and their families with regard to HIV- and AIDS-related information, and to formulate recommendations to improve their comprehension of this information. A quantitative, explorative and descriptive survey design was followed. Data were collected by means of questionnaires completed by HIV-positive patients (n= 79 and their family members (n= 34. Descriptive statistical analysis by means of frequency analysis was conducted. Ethical considerations and mechanisms to enhance validity and reliability are discussed. The results indicated that both HIV-positive respondents and their families face social and financial challenges due to unemployment and low income. A strength found in this research is that the majority of respondents are linked to a church, which can be a valuable platform to share information on HIV and AIDS. With regards to sharing, sources and comprehension of HIV- and AIDS-related information, it is apparent that respondents perceived that pre- and post-counselling provided an opportunity for information sharing, but that they need health care workers to spend more time with them, to be non-judgemental and to make more use of visual aids. It furthermore seems that the majority of HIV-positive respondents in this study did comprehend the need for and negotiate for safer sexual practices. It was concluded that although

  8. Robust Design of Sounds in Mechanical Mechanisms

    DEFF Research Database (Denmark)

    Boegedal Jensen, Annemette; Munch, Natasja; Howard, Thomas J.

    2015-01-01

    mechanism consisting of a toothed rack and a click arm. First several geometries of the teeth and the click arm’s head were investigated to identify the most robust and repeatable design. It was found that a flat surface in the valleys between the teeth is very beneficial in relation to repeatability...

  9. Characterization of complex networks : Application to robustness analysis

    NARCIS (Netherlands)

    Jamakovic, A.

    2008-01-01

    This thesis focuses on the topological characterization of complex networks. It specifically focuses on those elementary graph measures that are of interest when quantifying topology-related aspects of the robustness of complex networks. This thesis makes the following contributions to the field of

  10. Robust statistical methods with R

    CERN Document Server

    Jureckova, Jana

    2005-01-01

    Robust statistical methods were developed to supplement the classical procedures when the data violate classical assumptions. They are ideally suited to applied research across a broad spectrum of study, yet most books on the subject are narrowly focused, overly theoretical, or simply outdated. Robust Statistical Methods with R provides a systematic treatment of robust procedures with an emphasis on practical application.The authors work from underlying mathematical tools to implementation, paying special attention to the computational aspects. They cover the whole range of robust methods, including differentiable statistical functions, distance of measures, influence functions, and asymptotic distributions, in a rigorous yet approachable manner. Highlighting hands-on problem solving, many examples and computational algorithms using the R software supplement the discussion. The book examines the characteristics of robustness, estimators of real parameter, large sample properties, and goodness-of-fit tests. It...

  11. Robust Manufacturing Control

    CERN Document Server

    2013-01-01

    This contributed volume collects research papers, presented at the CIRP Sponsored Conference Robust Manufacturing Control: Innovative and Interdisciplinary Approaches for Global Networks (RoMaC 2012, Jacobs University, Bremen, Germany, June 18th-20th 2012). These research papers present the latest developments and new ideas focusing on robust manufacturing control for global networks. Today, Global Production Networks (i.e. the nexus of interconnected material and information flows through which products and services are manufactured, assembled and distributed) are confronted with and expected to adapt to: sudden and unpredictable large-scale changes of important parameters which are occurring more and more frequently, event propagation in networks with high degree of interconnectivity which leads to unforeseen fluctuations, and non-equilibrium states which increasingly characterize daily business. These multi-scale changes deeply influence logistic target achievement and call for robust planning and control ...

  12. Robustness - theoretical framework

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Rizzuto, Enrico; Faber, Michael H.

    2010-01-01

    More frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of new struct...... of this fact sheet is to describe a theoretical and risk based framework to form the basis for quantification of robustness and for pre-normative guidelines....

  13. Network position and related power : how they affect and are affected by network management and outcomes

    NARCIS (Netherlands)

    Oukes, Tamara

    2018-01-01

    In network position and related power you learn more about how network position and related power affect and are affected by network management and outcomes. First, I expand our present understanding of how startups with a fragile network position manage business relationships by taking an

  14. Robust anti-windup control for marine cyber-physical systems

    Directory of Open Access Journals (Sweden)

    Kakanov Mikhail

    2018-01-01

    Full Text Available In this paper the robust output control with anti-windup compensation and its implementation to the robotic boat are addressed. The detailed control design and stability analysis of the closed-loop systems are provided in the work. Extensive experimental verification of the dynamic positioning system based on various modifications of the basic controller is carried out by means of robotic boat. The corresponding experimental results are presented and analysed.

  15. Trajectories of higher- and lower-order dimensions of negative and positive affect relative to restrictive eating in anorexia nervosa.

    Science.gov (United States)

    Haynos, Ann F; Berg, Kelly C; Cao, Li; Crosby, Ross D; Lavender, Jason M; Utzinger, Linsey M; Wonderlich, Stephen A; Engel, Scott G; Mitchell, James E; Le Grange, Daniel; Peterson, Carol B; Crow, Scott J

    2017-07-01

    Despite robust support for the role of affect in the maintenance of binge eating and purging, the relationship between affect and restrictive eating remains poorly understood. To investigate the relationship between restrictive eating and affect, ecological momentary assessment data from 118 women with anorexia nervosa (AN) were used to examine trajectories of higher-order dimensions of negative affect (NA) and positive affect (PA), as well as lower-order dimensions of NA (Fear, Guilt) and PA (Joviality, Self-Assurance) relative to restrictive eating. Affect trajectories were modeled before and after restrictive eating episodes and AN subtype was examined as a moderator of these trajectories. Across the sample, Guilt significantly increased before and decreased after restrictive eating episodes. Global NA, Global PA, Fear, Joviality, and Self-Assurance did not vary relative to restrictive eating episodes across the sample. However, significant subtype by trajectory interactions were detected for PA indices. Among individuals with AN restricting subtype, Global PA, Joviality, and Self-Assurance decreased prior to and Self-Assurance increased following restrictive eating episodes. In contrast, Global PA and Self-Assurance increased prior to, but did not change following, restrictive eating episodes among individuals with AN binge eating/purging subtype. Results suggest that dietary restriction may function to mitigate guilt across AN subtypes and to enhance self-assurance among individuals with AN restricting subtype. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  16. Robustness Evaluation of Timber Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard; čizmar, D.

    2010-01-01

    The present paper outlines results from working group 3 (WG3) in the EU COST Action E55 – ‘Modelling of the performance of timber structures’. The objectives of the project are related to the three main research activities: the identification and modelling of relevant load and environmental...... exposure scenarios, the improvement of knowledge concerning the behaviour of timber structural elements and the development of a generic framework for the assessment of the life-cycle vulnerability and robustness of timber structures....

  17. Current irritability robustly related to current and prior anxiety in bipolar disorder.

    Science.gov (United States)

    Yuen, Laura D; Miller, Shefali; Wang, Po W; Hooshmand, Farnaz; Holtzman, Jessica N; Goffin, Kathryn C; Shah, Saloni; Ketter, Terence A

    2016-08-01

    Although current irritability and current/prior anxiety have been associated in unipolar depression, these relationships are less well understood in bipolar disorder (BD). We investigated relationships between current irritability and current/prior anxiety as well as other current emotions and BD illness characteristics. Outpatients referred to the Stanford Bipolar Disorders Clinic during 2000-2011 were assessed with the Systematic Treatment Enhancement Program for BD (STEP-BD) Affective Disorders Evaluation. Prevalence and clinical correlates of current irritability and current/prior anxiety and other illness characteristics were examined. Among 497 BD outpatients (239 Type I, 258 Type II; 58.1% female; mean ± SD age 35.6 ± 13.1 years), 301 (60.6%) had baseline current irritability. Patients with versus without current irritability had significantly higher rates of current anxiety (77.1% versus 42.9%, p anxiety disorder (73.1% versus 52.6%, p anxiety than to current anhedonia, sadness, or euphoria (all p anxiety associations persisted across current predominant mood states. Current irritability was more robustly related to past anxiety than to all other assessed illness characteristics, including 1° family history of mood disorder, history of alcohol/substance use disorder, bipolar subtype, and current syndromal/subsyndromal depression (all p anxiety. Further studies are warranted to assess longitudinal clinical implications of relationships between irritability and anxiety in BD. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Robust Floor Determination Algorithm for Indoor Wireless Localization Systems under Reference Node Failure

    Directory of Open Access Journals (Sweden)

    Kriangkrai Maneerat

    2016-01-01

    Full Text Available One of the challenging problems for indoor wireless multifloor positioning systems is the presence of reference node (RN failures, which cause the values of received signal strength (RSS to be missed during the online positioning phase of the location fingerprinting technique. This leads to performance degradation in terms of floor accuracy, which in turn affects other localization procedures. This paper presents a robust floor determination algorithm called Robust Mean of Sum-RSS (RMoS, which can accurately determine the floor on which mobile objects are located and can work under either the fault-free scenario or the RN-failure scenarios. The proposed fault tolerance floor algorithm is based on the mean of the summation of the strongest RSSs obtained from the IEEE 802.15.4 Wireless Sensor Networks (WSNs during the online phase. The performance of the proposed algorithm is compared with those of different floor determination algorithms in literature. The experimental results show that the proposed robust floor determination algorithm outperformed the other floor algorithms and can achieve the highest percentage of floor determination accuracy in all scenarios tested. Specifically, the proposed algorithm can achieve greater than 95% correct floor determination under the scenario in which 40% of RNs failed.

  19. What is shared, what is different? Core relational themes and expressive displays of eight positive emotions.

    Science.gov (United States)

    Campos, Belinda; Shiota, Michelle N; Keltner, Dacher; Gonzaga, Gian C; Goetz, Jennifer L

    2013-01-01

    Understanding positive emotions' shared and differentiating features can yield valuable insight into the structure of positive emotion space and identify emotion states, or aspects of emotion states, that are most relevant for particular psychological processes and outcomes. We report two studies that examined core relational themes (Study 1) and expressive displays (Study 2) for eight positive emotion constructs--amusement, awe, contentment, gratitude, interest, joy, love, and pride. Across studies, all eight emotions shared one quality: high positive valence. Distinctive core relational theme and expressive display patterns were found for four emotions--amusement, awe, interest, and pride. Gratitude was associated with a distinct core relational theme but not an expressive display. Joy and love were each associated with a distinct expressive display but their core relational themes also characterised pride and gratitude, respectively. Contentment was associated with a distinct expressive display but not a core relational theme. The implications of this work for the study of positive emotion are discussed.

  20. The influence of nationality and playing position on relative age ...

    African Journals Online (AJOL)

    Kathryn van Boom

    for this phenomenon, termed the relative age effect (RAE), is that children born in the ... of countries have introduced modified games or weight categories in some ... A review of an online database (http://www.itsrugby.co.uk/) revealed the names ... positive SR indicated a higher than expected number of births in that quarter.

  1. A Comparative Theoretical and Computational Study on Robust Counterpart Optimization: I. Robust Linear Optimization and Robust Mixed Integer Linear Optimization

    Science.gov (United States)

    Li, Zukui; Ding, Ran; Floudas, Christodoulos A.

    2011-01-01

    Robust counterpart optimization techniques for linear optimization and mixed integer linear optimization problems are studied in this paper. Different uncertainty sets, including those studied in literature (i.e., interval set; combined interval and ellipsoidal set; combined interval and polyhedral set) and new ones (i.e., adjustable box; pure ellipsoidal; pure polyhedral; combined interval, ellipsoidal, and polyhedral set) are studied in this work and their geometric relationship is discussed. For uncertainty in the left hand side, right hand side, and objective function of the optimization problems, robust counterpart optimization formulations induced by those different uncertainty sets are derived. Numerical studies are performed to compare the solutions of the robust counterpart optimization models and applications in refinery production planning and batch process scheduling problem are presented. PMID:21935263

  2. Robust sliding mode control for uncertain servo system using friction observer and recurrent fuzzy neural networks

    International Nuclear Information System (INIS)

    Han, Seong Ik; Jeong, Chan Se; Yang, Soon Yong

    2012-01-01

    A robust positioning control scheme has been developed using friction parameter observer and recurrent fuzzy neural networks based on the sliding mode control. As a dynamic friction model, the LuGre model is adopted for handling friction compensation because it has been known to capture sufficiently the properties of a nonlinear dynamic friction. A developed friction parameter observer has a simple structure and also well estimates friction parameters of the LuGre friction model. In addition, an approximation method for the system uncertainty is developed using recurrent fuzzy neural networks technology to improve the precision positioning degree. Some simulation and experiment provide the verification on the performance of a proposed robust control scheme

  3. Robust sliding mode control for uncertain servo system using friction observer and recurrent fuzzy neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seong Ik [Pusan National University, Busan (Korea, Republic of); Jeong, Chan Se; Yang, Soon Yong [University of Ulsan, Ulsan (Korea, Republic of)

    2012-04-15

    A robust positioning control scheme has been developed using friction parameter observer and recurrent fuzzy neural networks based on the sliding mode control. As a dynamic friction model, the LuGre model is adopted for handling friction compensation because it has been known to capture sufficiently the properties of a nonlinear dynamic friction. A developed friction parameter observer has a simple structure and also well estimates friction parameters of the LuGre friction model. In addition, an approximation method for the system uncertainty is developed using recurrent fuzzy neural networks technology to improve the precision positioning degree. Some simulation and experiment provide the verification on the performance of a proposed robust control scheme.

  4. Robustness of the ATLAS pixel clustering neural network algorithm

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00407780; The ATLAS collaboration

    2016-01-01

    Proton-proton collisions at the energy frontier puts strong constraints on track reconstruction algorithms. The algorithms depend heavily on accurate estimation of the position of particles as they traverse the inner detector elements. An artificial neural network algorithm is utilised to identify and split clusters of neighbouring read-out elements in the ATLAS pixel detector created by multiple charged particles. The method recovers otherwise lost tracks in dense environments where particles are separated by distances comparable to the size of the detector read-out elements. Such environments are highly relevant for LHC run 2, e.g. in searches for heavy resonances. Within the scope of run 2 track reconstruction performance and upgrades, the robustness of the neural network algorithm will be presented. The robustness has been studied by evaluating the stability of the algorithm’s performance under a range of variations in the pixel detector conditions.

  5. Robust procedures in chemometrics

    DEFF Research Database (Denmark)

    Kotwa, Ewelina

    properties of the analysed data. The broad theoretical background of robust procedures was given as a very useful supplement to the classical methods, and a new tool, based on robust PCA, aiming at identifying Rayleigh and Raman scatters in excitation-mission (EEM) data was developed. The results show...

  6. Robust canonical correlations: A comparative study

    OpenAIRE

    Branco, JA; Croux, Christophe; Filzmoser, P; Oliveira, MR

    2005-01-01

    Several approaches for robust canonical correlation analysis will be presented and discussed. A first method is based on the definition of canonical correlation analysis as looking for linear combinations of two sets of variables having maximal (robust) correlation. A second method is based on alternating robust regressions. These methods axe discussed in detail and compared with the more traditional approach to robust canonical correlation via covariance matrix estimates. A simulation study ...

  7. Cancer-related identity and positive affect in survivors of prostate cancer.

    Science.gov (United States)

    Bellizzi, Keith M; Blank, Thomas O

    2007-03-01

    Despite a shift in the cancer culture and language used to describe individuals diagnosed with this disease, the extent to which individuals with cancer adopt a particular cancer-related identity and the impact of these identities in relation to their well-being is virtually unknown. Using a cross-sectional study design and a metropolitan tumor registry, a mail questionnaire to examine post-treatment quality of life was sent to prostate cancer (PCa) survivors. The sample consisted of 490 PCa survivors, ranging in age from 49-88 (M = 69.7; SD = 7.8), one to eight years after diagnosis. The outcome measure used in these analyses was the PANAS to assess positive and negative affect. The most frequently reported cancer-related identity was "someone who has had PCa" (57%). The least reported self view was "victim" (1%). Twenty-six percent of men self-identified as "survivors" while 6% thought of themselves as "cancer conquerors." Only 9% self-identified as a "patient." Multivariate analyses, adjusted for potential confounders, show respondents who identified themselves as "survivors" or "cancer conquerors" reported significantly higher scores on positive affect than men who self-identified as "patients" (p < .001). Although the majority of respondents identified themselves as "someone who has had cancer," identifying as a "survivor" or "someone who has conquered cancer" appears to have adaptive value for positive mood. Those who perceive themselves as survivors of prostate cancer may derive some benefit in well-being associated with this self assessment.

  8. Does a Positive Bias Relate to Social Behavior in Children with ADHD?

    Science.gov (United States)

    Linnea, Kate; Hoza, Betsy; Tomb, Meghan; Kaiser, Nina

    2012-01-01

    This study examines whether positively biased self-perceptions relate to social behaviors in children with attention-deficit/hyperactivity disorder (ADHD) as compared to control children. The social behaviors of children with ADHD (n = 87) were examined relative to control children (CTL; n = 38) during a laboratory-based dyadic social interaction…

  9. Relational aggression, positive urgency and negative urgency: predicting alcohol use and consequences among college students.

    Science.gov (United States)

    Grimaldi, Elizabeth M; Napper, Lucy E; LaBrie, Joseph W

    2014-09-01

    Research on relational aggression (indirect and social means of inflicting harm) has previously focused on adolescent populations. The current study extends this research by exploring both the frequency of perpetrating and being the target of relational aggression as it relates to alcohol use outcomes in a college population. Further, this study examines whether positive urgency (e.g., acting impulsively in response to positive emotions) and negative urgency (e.g., acting impulsively in response to negative emotions) moderate the relationship between relational aggression and alcohol outcomes. In this study, 245 college students (65.7% female) completed an online survey. Results indicated greater frequency of perpetrating relational aggression, higher levels of positive urgency, or higher levels of negative urgency was associated with more negative consequences. Further, negative urgency moderated the relationship between frequency of perpetrating aggression and consequences such that aggression was more strongly associated with consequences for those high in urgency. Counter to the adolescent literature, the frequency of being the target of aggression was not associated with more alcohol use. These findings suggest that perpetrators of relational aggression may be at particular risk for negative alcohol-related consequences when they act impulsively in response to negative, but not positive, emotions. These students may benefit from interventions exploring alternative ways to cope with negative emotions.

  10. Robust Sequential Covariance Intersection Fusion Kalman Filtering over Multi-agent Sensor Networks with Measurement Delays and Uncertain Noise Variances

    Institute of Scientific and Technical Information of China (English)

    QI Wen-Juan; ZHANG Peng; DENG Zi-Li

    2014-01-01

    This paper deals with the problem of designing robust sequential covariance intersection (SCI) fusion Kalman filter for the clustering multi-agent sensor network system with measurement delays and uncertain noise variances. The sensor network is partitioned into clusters by the nearest neighbor rule. Using the minimax robust estimation principle, based on the worst-case conservative sensor network system with conservative upper bounds of noise variances, and applying the unbiased linear minimum variance (ULMV) optimal estimation rule, we present the two-layer SCI fusion robust steady-state Kalman filter which can reduce communication and computation burdens and save energy sources, and guarantee that the actual filtering error variances have a less-conservative upper-bound. A Lyapunov equation method for robustness analysis is proposed, by which the robustness of the local and fused Kalman filters is proved. The concept of the robust accuracy is presented and the robust accuracy relations of the local and fused robust Kalman filters are proved. It is proved that the robust accuracy of the global SCI fuser is higher than those of the local SCI fusers and the robust accuracies of all SCI fusers are higher than that of each local robust Kalman filter. A simulation example for a tracking system verifies the robustness and robust accuracy relations.

  11. Income and Well-Being: Relative Income and Absolute Income Weaken Negative Emotion, but Only Relative Income Improves Positive Emotion.

    Science.gov (United States)

    Yu, Zonghuo; Chen, Li

    2016-01-01

    Whether relative income or absolute income could affect subjective well-being has been a bone of contention for years. Life satisfaction and the relative frequency of positive and negative emotions are parts of subjective well-being. According to the prospect theory, hedonic adaptation helps to explain why positive emotion is often so hard to be maintained, and negative emotion wouldn't be easy to be eliminated. So we expect the relationship between income and positive emotion is different from that between income and negative emotion. Given that regional reference is the main comparison mechanism, effects of regional average income on regional average subjective well-being should be potentially zero if only relative income matters. Using multilevel analysis, we tested the hypotheses with a dataset of 30,144 individuals from 162 counties in China. The results suggested that household income at the individual level is associated with life satisfaction, happiness and negative emotions. On the contrary, at a county level, household income is only associated with negative emotion. In other words, happiness and life satisfaction was only associated with relative income, but negative emotion was associated with relative income and absolute income. Without social comparison, income doesn't improve happiness, but it could weaken negative emotion. Therefore, it is possible for economic growth to weaken negative emotion without improving happiness. These findings also contribute to the current debate about the "Esterling paradox."

  12. Consistent robustness analysis (CRA) identifies biologically relevant properties of regulatory network models.

    Science.gov (United States)

    Saithong, Treenut; Painter, Kevin J; Millar, Andrew J

    2010-12-16

    A number of studies have previously demonstrated that "goodness of fit" is insufficient in reliably classifying the credibility of a biological model. Robustness and/or sensitivity analysis is commonly employed as a secondary method for evaluating the suitability of a particular model. The results of such analyses invariably depend on the particular parameter set tested, yet many parameter values for biological models are uncertain. Here, we propose a novel robustness analysis that aims to determine the "common robustness" of the model with multiple, biologically plausible parameter sets, rather than the local robustness for a particular parameter set. Our method is applied to two published models of the Arabidopsis circadian clock (the one-loop [1] and two-loop [2] models). The results reinforce current findings suggesting the greater reliability of the two-loop model and pinpoint the crucial role of TOC1 in the circadian network. Consistent Robustness Analysis can indicate both the relative plausibility of different models and also the critical components and processes controlling each model.

  13. MDEP Common Position CP-STC-02. Common Position Addressing Fukushima Daiichi Nuclear Power Accident

    International Nuclear Information System (INIS)

    2016-09-01

    Following the nuclear accident in Japan as a consequence of the earthquake and tsunami, the MDEP Members provide the following information, based on initial information available, to ensure adequate safety of new reactor design activities being undertaken pursuant to the MDEP program of work. Due to the extensive nature of the magnitude and duration of the Fukushima Daiichi NPP accident, it is important to consider lessons learnt at an early stage of the design. In this context, the extensive work done by the IAEA, the International Atomic Energy Agency, is also acknowledged. Vendors, licensees and applicants involved in New Design activities should examine the implications of the Fukushima Daiichi NPP accident and identify relevant issues to be taken into account to strengthen defense in depth. Those lessons learnt should include, but not be limited to, plans to assess the following: - Provisions taken in the design basis concerning flooding, earthquake, other extreme natural phenomena and combinations of external event hazards appropriate to each country, - The robustness of the plant to maintain its safety functions beyond the design basis hazards, - The capability of the plant to withstand extended loss of all electrical power supplies as well as prolonged loss of ultimate heat sink and other essential supplies, and - The capability of the plant to cope with such extreme situations, including provisions to manage severe accidents (such as combustible gas management). In assessing these areas, the effect of multiple units and nuclear fuel storages should be considered. The MDEP regulators will strive to harmonize approaches to incorporate lessons learnt in their ongoing national safety reviews of new reactors. Based on the design-specific common positions, this paper identifies the approaches to address potential safety improvements for several designs as related to lessons learned from the Fukushima Daiichi NPP accident or related issues. Designs being

  14. Muscle Synergy-Driven Robust Motion Control.

    Science.gov (United States)

    Min, Kyuengbo; Iwamoto, Masami; Kakei, Shinji; Kimpara, Hideyuki

    2018-04-01

    Humans are able to robustly maintain desired motion and posture under dynamically changing circumstances, including novel conditions. To accomplish this, the brain needs to optimize the synergistic control between muscles against external dynamic factors. However, previous related studies have usually simplified the control of multiple muscles using two opposing muscles, which are minimum actuators to simulate linear feedback control. As a result, they have been unable to analyze how muscle synergy contributes to motion control robustness in a biological system. To address this issue, we considered a new muscle synergy concept used to optimize the synergy between muscle units against external dynamic conditions, including novel conditions. We propose that two main muscle control policies synergistically control muscle units to maintain the desired motion against external dynamic conditions. Our assumption is based on biological evidence regarding the control of multiple muscles via the corticospinal tract. One of the policies is the group control policy (GCP), which is used to control muscle group units classified based on functional similarities in joint control. This policy is used to effectively resist external dynamic circumstances, such as disturbances. The individual control policy (ICP) assists the GCP in precisely controlling motion by controlling individual muscle units. To validate this hypothesis, we simulated the reinforcement of the synergistic actions of the two control policies during the reinforcement learning of feedback motion control. Using this learning paradigm, the two control policies were synergistically combined to result in robust feedback control under novel transient and sustained disturbances that did not involve learning. Further, by comparing our data to experimental data generated by human subjects under the same conditions as those of the simulation, we showed that the proposed synergy concept may be used to analyze muscle synergy

  15. Robust plasmonic substrates

    DEFF Research Database (Denmark)

    Kostiučenko, Oksana; Fiutowski, Jacek; Tamulevicius, Tomas

    2014-01-01

    Robustness is a key issue for the applications of plasmonic substrates such as tip-enhanced Raman spectroscopy, surface-enhanced spectroscopies, enhanced optical biosensing, optical and optoelectronic plasmonic nanosensors and others. A novel approach for the fabrication of robust plasmonic...... substrates is presented, which relies on the coverage of gold nanostructures with diamond-like carbon (DLC) thin films of thicknesses 25, 55 and 105 nm. DLC thin films were grown by direct hydrocarbon ion beam deposition. In order to find the optimum balance between optical and mechanical properties...

  16. A robust standard deviation control chart

    NARCIS (Netherlands)

    Schoonhoven, M.; Does, R.J.M.M.

    2012-01-01

    This article studies the robustness of Phase I estimators for the standard deviation control chart. A Phase I estimator should be efficient in the absence of contaminations and resistant to disturbances. Most of the robust estimators proposed in the literature are robust against either diffuse

  17. Robust Operation of Tendon-Driven Robot Fingers Using Force and Position-Based Control Laws

    Science.gov (United States)

    Abdallah, Muhammad E (Inventor); Platt, Jr., Robert J. (Inventor); Reiland, Matthew J (Inventor); Hargrave, Brian (Inventor); Diftler, Myron A (Inventor); Strawser, Philip A (Inventor); Ihrke, Chris A. (Inventor)

    2013-01-01

    A robotic system includes a tendon-driven finger and a control system. The system controls the finger via a force-based control law when a tension sensor is available, and via a position-based control law when a sensor is not available. Multiple tendons may each have a corresponding sensor. The system selectively injects a compliance value into the position-based control law when only some sensors are available. A control system includes a host machine and a non-transitory computer-readable medium having a control process, which is executed by the host machine to control the finger via the force- or position-based control law. A method for controlling the finger includes determining the availability of a tension sensor(s), and selectively controlling the finger, using the control system, via the force or position-based control law. The position control law allows the control system to resist disturbances while nominally maintaining the initial state of internal tendon tensions.

  18. Hybrid Robust Optimization for the Design of a Smartphone Metal Frame Antenna

    Directory of Open Access Journals (Sweden)

    Sungwoo Lee

    2018-01-01

    Full Text Available Hybrid robust optimization that combines a genetical swarm optimization (GSO scheme with an orthogonal array (OA is proposed to design an antenna robust to the tolerances arising during the fabrication process of the antenna in this paper. An inverted-F antenna with a metal frame serves as an example to explain the procedure of the proposed method. GSO is adapted to determine the design variables of the antenna, which operates on the GSM850 band (824–894 MHz. The robustness of the antenna is evaluated through a noise test using the OA. The robustness of the optimized antenna is improved by approximately 61.3% relative to that of a conventional antenna. Conventional and optimized antennas are fabricated and measured to validate the experimental results.

  19. Obesity-related behaviors among poor adolescents and young adults: Is social position associated with risk behaviors?

    Directory of Open Access Journals (Sweden)

    Miranda Lucia Ritterman Weintraub

    2015-10-01

    Full Text Available This cross-sectional study examines multiple dimensions of social position in relation to obesity-related behaviors in an adolescent and young adult population. In addition to using conventional measures of social position, including parental education and household expenditures, we explore the usefulness of three youth-specific measures of social position—community and society subjective social status and school dropout status. Data is taken from a 2004 house-to-house survey of urban households within the bottom 20th percentile of income distribution within seven states in Mexico. A total of 5,321 Mexican adolescents, aged 12-22 years, provided information on obesity-related behaviors (e.g. diet, physical activity, sedentary behavior and indicators of subjective and objective social position. A parent in each household provided information on socioeconomic status of the parent and household. Ordinal logistic regressions are used to estimate the associations of parental, household and adolescent indicators of social position and obesity-related risk behaviors. Those adolescents with the highest odds of adopting obesity risk behaviors were the ones who perceived themselves as lower in social status in reference to their peer community and those who had dropped out of school. We found no significant associations between parental education or household expenditures and obesity-related risk behaviors. Immediate social factors in adolescents' lives may have a strong influence on their health-related behaviors. This study provides evidence for the usefulness of two particular measures, both of which are youth-specific. Adolescents and young adults who have dropped out of school and those with lower perceived relative social position within their community are more likely to be at-risk for obesity-related behaviors than those with higher relative social position. We conclude that youth-specific measures may be important in identifying the most at

  20. Investigation on changes of modularity and robustness by edge-removal mutations in signaling networks.

    Science.gov (United States)

    Truong, Cong-Doan; Kwon, Yung-Keun

    2017-12-21

    Biological networks consisting of molecular components and interactions are represented by a graph model. There have been some studies based on that model to analyze a relationship between structural characteristics and dynamical behaviors in signaling network. However, little attention has been paid to changes of modularity and robustness in mutant networks. In this paper, we investigated the changes of modularity and robustness by edge-removal mutations in three signaling networks. We first observed that both the modularity and robustness increased on average in the mutant network by the edge-removal mutations. However, the modularity change was negatively correlated with the robustness change. This implies that it is unlikely that both the modularity and the robustness values simultaneously increase by the edge-removal mutations. Another interesting finding is that the modularity change was positively correlated with the degree, the number of feedback loops, and the edge betweenness of the removed edges whereas the robustness change was negatively correlated with them. We note that these results were consistently observed in randomly structure networks. Additionally, we identified two groups of genes which are incident to the highly-modularity-increasing and the highly-robustness-decreasing edges with respect to the edge-removal mutations, respectively, and observed that they are likely to be central by forming a connected component of a considerably large size. The gene-ontology enrichment of each of these gene groups was significantly different from the rest of genes. Finally, we showed that the highly-robustness-decreasing edges can be promising edgetic drug-targets, which validates the usefulness of our analysis. Taken together, the analysis of changes of robustness and modularity against edge-removal mutations can be useful to unravel novel dynamical characteristics underlying in signaling networks.

  1. Robustness: confronting lessons from physics and biology.

    Science.gov (United States)

    Lesne, Annick

    2008-11-01

    The term robustness is encountered in very different scientific fields, from engineering and control theory to dynamical systems to biology. The main question addressed herein is whether the notion of robustness and its correlates (stability, resilience, self-organisation) developed in physics are relevant to biology, or whether specific extensions and novel frameworks are required to account for the robustness properties of living systems. To clarify this issue, the different meanings covered by this unique term are discussed; it is argued that they crucially depend on the kind of perturbations that a robust system should by definition withstand. Possible mechanisms underlying robust behaviours are examined, either encountered in all natural systems (symmetries, conservation laws, dynamic stability) or specific to biological systems (feedbacks and regulatory networks). Special attention is devoted to the (sometimes counterintuitive) interrelations between robustness and noise. A distinction between dynamic selection and natural selection in the establishment of a robust behaviour is underlined. It is finally argued that nested notions of robustness, relevant to different time scales and different levels of organisation, allow one to reconcile the seemingly contradictory requirements for robustness and adaptability in living systems.

  2. Environmental Noise, Genetic Diversity and the Evolution of Evolvability and Robustness in Model Gene Networks

    Science.gov (United States)

    Steiner, Christopher F.

    2012-01-01

    The ability of organisms to adapt and persist in the face of environmental change is accepted as a fundamental feature of natural systems. More contentious is whether the capacity of organisms to adapt (or “evolvability”) can itself evolve and the mechanisms underlying such responses. Using model gene networks, I provide evidence that evolvability emerges more readily when populations experience positively autocorrelated environmental noise (red noise) compared to populations in stable or randomly varying (white noise) environments. Evolvability was correlated with increasing genetic robustness to effects on network viability and decreasing robustness to effects on phenotypic expression; populations whose networks displayed greater viability robustness and lower phenotypic robustness produced more additive genetic variation and adapted more rapidly in novel environments. Patterns of selection for robustness varied antagonistically with epistatic effects of mutations on viability and phenotypic expression, suggesting that trade-offs between these properties may constrain their evolutionary responses. Evolution of evolvability and robustness was stronger in sexual populations compared to asexual populations indicating that enhanced genetic variation under fluctuating selection combined with recombination load is a primary driver of the emergence of evolvability. These results provide insight into the mechanisms potentially underlying rapid adaptation as well as the environmental conditions that drive the evolution of genetic interactions. PMID:23284934

  3. Perceived positive and negative consequences after surviving cancer and their relation to quality of life.

    Science.gov (United States)

    Castellano-Tejedor, Carmina; Eiroa-Orosa, Francisco-José; Pérez-Campdepadrós, Marta; Capdevila, Lluís; Sánchez de Toledo, José; Blasco-Blasco, Tomás

    2015-06-01

    Surviving childhood cancer has multiple implications on both physical and psychological domains of the individual. However, its study and possible effects on health-related quality of life (HRQoL) outcomes of adolescent survivors has been understudied. The objective of this study was twofold; to assess positive and negative cancer-related consequences (psychosocial and physical) in a sample of adolescent cancer survivors and to explore their relationship with HRQoL outcomes. Forty-one participants answered two questions about positive and negative consequences in the aftermath of cancer and filled in the KIDSCREEN-52 self-reported version. Data were analysed using mixed methods approach. Overall, 87.8% of the studied sample identified positive consequences and 63.4% negative consequences in survivorship. Four positive categories and five negative categories with regard to cancer-related consequences were found. Changed perspectives in life narratives seem to be the positive consequence more related to HRQoL (physical well-being, mood & emotions, autonomy, social support & peers), followed by useful life experience (physical well-being, autonomy, social support & peers). Psychological impact was the most referred negative consequence with a significant detrimental effect on social support and peers HRQoL dimension. Even if the majority of survivors reported benefit finding in the aftermath of cancer, concomitant positive and negative consequences have been found. However, findings only reveal a significant relationship between positive narratives and HRQoL, and negative consequences do not seem to have a significant influence on overall HRQoL in survivorship. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  4. GPU-accelerated automatic identification of robust beam setups for proton and carbon-ion radiotherapy

    International Nuclear Information System (INIS)

    Ammazzalorso, F; Jelen, U; Bednarz, T

    2014-01-01

    We demonstrate acceleration on graphic processing units (GPU) of automatic identification of robust particle therapy beam setups, minimizing negative dosimetric effects of Bragg peak displacement caused by treatment-time patient positioning errors. Our particle therapy research toolkit, RobuR, was extended with OpenCL support and used to implement calculation on GPU of the Port Homogeneity Index, a metric scoring irradiation port robustness through analysis of tissue density patterns prior to dose optimization and computation. Results were benchmarked against an independent native CPU implementation. Numerical results were in agreement between the GPU implementation and native CPU implementation. For 10 skull base cases, the GPU-accelerated implementation was employed to select beam setups for proton and carbon ion treatment plans, which proved to be dosimetrically robust, when recomputed in presence of various simulated positioning errors. From the point of view of performance, average running time on the GPU decreased by at least one order of magnitude compared to the CPU, rendering the GPU-accelerated analysis a feasible step in a clinical treatment planning interactive session. In conclusion, selection of robust particle therapy beam setups can be effectively accelerated on a GPU and become an unintrusive part of the particle therapy treatment planning workflow. Additionally, the speed gain opens new usage scenarios, like interactive analysis manipulation (e.g. constraining of some setup) and re-execution. Finally, through OpenCL portable parallelism, the new implementation is suitable also for CPU-only use, taking advantage of multiple cores, and can potentially exploit types of accelerators other than GPUs.

  5. GPU-accelerated automatic identification of robust beam setups for proton and carbon-ion radiotherapy

    Science.gov (United States)

    Ammazzalorso, F.; Bednarz, T.; Jelen, U.

    2014-03-01

    We demonstrate acceleration on graphic processing units (GPU) of automatic identification of robust particle therapy beam setups, minimizing negative dosimetric effects of Bragg peak displacement caused by treatment-time patient positioning errors. Our particle therapy research toolkit, RobuR, was extended with OpenCL support and used to implement calculation on GPU of the Port Homogeneity Index, a metric scoring irradiation port robustness through analysis of tissue density patterns prior to dose optimization and computation. Results were benchmarked against an independent native CPU implementation. Numerical results were in agreement between the GPU implementation and native CPU implementation. For 10 skull base cases, the GPU-accelerated implementation was employed to select beam setups for proton and carbon ion treatment plans, which proved to be dosimetrically robust, when recomputed in presence of various simulated positioning errors. From the point of view of performance, average running time on the GPU decreased by at least one order of magnitude compared to the CPU, rendering the GPU-accelerated analysis a feasible step in a clinical treatment planning interactive session. In conclusion, selection of robust particle therapy beam setups can be effectively accelerated on a GPU and become an unintrusive part of the particle therapy treatment planning workflow. Additionally, the speed gain opens new usage scenarios, like interactive analysis manipulation (e.g. constraining of some setup) and re-execution. Finally, through OpenCL portable parallelism, the new implementation is suitable also for CPU-only use, taking advantage of multiple cores, and can potentially exploit types of accelerators other than GPUs.

  6. 78 FR 31847 - Designation of National Security Positions in the Competitive Service, and Related Matters

    Science.gov (United States)

    2013-05-28

    ...) Positions requiring eligibility for access to Top Secret or ``Q'' classified information; (ii) Positions... information classified at the Top Secret or ``Q'' level; (xix) Positions working with significant life... intelligence-related Special Sensitive information, requiring involvement in Top Secret Special Access Programs...

  7. Does positivity mediate the relation of extraversion and neuroticism with subjective happiness?

    Science.gov (United States)

    Lauriola, Marco; Iani, Luca

    2015-01-01

    Recent theories suggest an important role of neuroticism, extraversion, attitudes, and global positive orientations as predictors of subjective happiness. We examined whether positivity mediates the hypothesized relations in a community sample of 504 adults between the ages of 20 and 60 years old (females = 50%). A model with significant paths from neuroticism to subjective happiness, from extraversion and neuroticism to positivity, and from positivity to subjective happiness fitted the data (Satorra-Bentler scaled chi-square (38) = 105.91; Comparative Fit Index = .96; Non-Normed Fit Index = .95; Root Mean Square Error of Approximation = .060; 90% confidence interval = .046, .073). The percentage of subjective happiness variance accounted for by personality traits was only about 48%, whereas adding positivity as a mediating factor increased the explained amount of subjective happiness to 78%. The mediation model was invariant by age and gender. The results show that the effect of extraversion on happiness was fully mediated by positivity, whereas the effect of neuroticism was only partially mediated. Implications for happiness studies are also discussed.

  8. Robust AIC with High Breakdown Scale Estimate

    Directory of Open Access Journals (Sweden)

    Shokrya Saleh

    2014-01-01

    Full Text Available Akaike Information Criterion (AIC based on least squares (LS regression minimizes the sum of the squared residuals; LS is sensitive to outlier observations. Alternative criterion, which is less sensitive to outlying observation, has been proposed; examples are robust AIC (RAIC, robust Mallows Cp (RCp, and robust Bayesian information criterion (RBIC. In this paper, we propose a robust AIC by replacing the scale estimate with a high breakdown point estimate of scale. The robustness of the proposed methods is studied through its influence function. We show that, the proposed robust AIC is effective in selecting accurate models in the presence of outliers and high leverage points, through simulated and real data examples.

  9. How robust is the relationship between economic freedom and economic growth?

    NARCIS (Netherlands)

    Sturm, JE; De Haan, J

    Using various indicators for economic freedom, it is shown that increases in economic freedom are robustly related to economic growth. This conclusion holds even if the impact of outlying observations is taken into account. The level of economic freedom is not related to growth.

  10. Generation model of positional values as cell operation during the development of multicellular organisms.

    Science.gov (United States)

    Ogawa, Ken-ichiro; Miyake, Yoshihiro

    2011-03-01

    Many conventional models have used the positional information hypothesis to explain each elementary process of morphogenesis during the development of multicellular organisms. Their models assume that the steady concentration patterns of morphogens formed in an extracellular environment have an important property of positional information, so-called "robustness". However, recent experiments reported that a steady morphogen pattern, the concentration gradient of the Bicoid protein, during early Drosophila embryonic development is not robust for embryo-to-embryo variability. These reports encourage a reconsideration of a long-standing problem in systematic cell differentiation: what is the entity of positional information for cells? And, what is the origin of the robust boundary of gene expression? To address these problems at a cellular level, in this article we pay attention to the re-generative phenomena that show another important property of positional information, "size invariance". In view of regenerative phenomena, we propose a new mathematical model to describe the generation mechanism of a spatial pattern of positional values. In this model, the positional values are defined as the values into which differentiable cells transform a spatial pattern providing positional information. The model is mathematically described as an associative algebra composed of various terms, each of which is the multiplication of some fundamental operators under the assumption that the operators are derived from the remarkable properties of cell differentiation on an amputation surface in regenerative phenomena. We apply this model to the concentration pattern of the Bicoid protein during the anterior-posterior axis formation in Drosophila, and consider the conditions needed to establish the robust boundary of the expression of the hunchback gene. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  11. Methodology in robust and nonparametric statistics

    CERN Document Server

    Jurecková, Jana; Picek, Jan

    2012-01-01

    Introduction and SynopsisIntroductionSynopsisPreliminariesIntroductionInference in Linear ModelsRobustness ConceptsRobust and Minimax Estimation of LocationClippings from Probability and Asymptotic TheoryProblemsRobust Estimation of Location and RegressionIntroductionM-EstimatorsL-EstimatorsR-EstimatorsMinimum Distance and Pitman EstimatorsDifferentiable Statistical FunctionsProblemsAsymptotic Representations for L-Estimators

  12. Robust Backlash Estimation for Industrial Drive-Train Systems—Theory and Validation

    DEFF Research Database (Denmark)

    Papageorgiou, Dimitrios; Blanke, Mogens; Niemann, Hans Henrik

    2018-01-01

    Backlash compensation is used in modern machinetool controls to ensure high-accuracy positioning. When wear of a machine causes deadzone width to increase, high-accuracy control may be maintained if the deadzone is accurately estimated. Deadzone estimation is also an important parameter to indica......-of-the-art Siemens equipment. The experiments validate the theory and show that expected performance and robustness to parameter uncertainties are both achieved....

  13. Robust microfluidic encapsulation of cholesteric liquid crystals toward photonic ink capsules.

    Science.gov (United States)

    Lee, Sang Seok; Kim, Bomi; Kim, Su Kyung; Won, Jong Chan; Kim, Yun Ho; Kim, Shin-Hyun

    2015-01-27

    Robust photonic microcapsules are created by microfluidic encapsulation of cholesteric liquid crystals with a hydrogel membrane. The membrane encloses the cholesteric core without leakage in water and the core exhibits pronounced structural colors. The photonic ink capsules, which have a precisely controlled bandgap position and size, provide new opportunities in colorimetric micro-thermometers and optoelectric applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Robust MR spine detection using hierarchical learning and local articulated model.

    Science.gov (United States)

    Zhan, Yiqiang; Maneesh, Dewan; Harder, Martin; Zhou, Xiang Sean

    2012-01-01

    A clinically acceptable auto-spine detection system, i.e., localization and labeling of vertebrae and inter-vertebral discs, is required to have high robustness, in particular to severe diseases (e.g., scoliosis) and imaging artifacts (e.g. metal artifacts in MR). Our method aims to achieve this goal with two novel components. First, instead of treating vertebrae/discs as either repetitive components or completely independent entities, we emulate a radiologist and use a hierarchial strategy to learn detectors dedicated to anchor (distinctive) vertebrae, bundle (non-distinctive) vertebrae and inter-vertebral discs, respectively. At run-time, anchor vertebrae are detected concurrently to provide redundant and distributed appearance cues robust to local imaging artifacts. Bundle vertebrae detectors provide candidates of vertebrae with subtle appearance differences, whose labels are mutually determined by anchor vertebrae to gain additional robustness. Disc locations are derived from a cloud of responses from disc detectors, which is robust to sporadic voxel-level errors. Second, owing to the non-rigidness of spine anatomies, we employ a local articulated model to effectively model the spatial relations across vertebrae and discs. The local articulated model fuses appearance cues from different detectors in a way that is robust to abnormal spine geometry resulting from severe diseases. Our method is validated by 300 MR spine scout scans and exhibits robust performance, especially to cases with severe diseases and imaging artifacts.

  15. Robust Approaches to Forecasting

    OpenAIRE

    Jennifer Castle; David Hendry; Michael P. Clements

    2014-01-01

    We investigate alternative robust approaches to forecasting, using a new class of robust devices, contrasted with equilibrium correction models. Their forecasting properties are derived facing a range of likely empirical problems at the forecast origin, including measurement errors, implulses, omitted variables, unanticipated location shifts and incorrectly included variables that experience a shift. We derive the resulting forecast biases and error variances, and indicate when the methods ar...

  16. Theoretical Framework for Robustness Evaluation

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2011-01-01

    This paper presents a theoretical framework for evaluation of robustness of structural systems, incl. bridges and buildings. Typically modern structural design codes require that ‘the consequence of damages to structures should not be disproportional to the causes of the damages’. However, although...... the importance of robustness for structural design is widely recognized the code requirements are not specified in detail, which makes the practical use difficult. This paper describes a theoretical and risk based framework to form the basis for quantification of robustness and for pre-normative guidelines...

  17. Robust portfolio selection under norm uncertainty

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2016-06-01

    Full Text Available Abstract In this paper, we consider the robust portfolio selection problem which has a data uncertainty described by the ( p , w $(p,w$ -norm in the objective function. We show that the robust formulation of this problem is equivalent to a linear optimization problem. Moreover, we present some numerical results concerning our robust portfolio selection problem.

  18. Robustness testing in pharmaceutical freeze-drying: inter-relation of process conditions and product quality attributes studied for a vaccine formulation.

    Science.gov (United States)

    Schneid, Stefan C; Stärtzel, Peter M; Lettner, Patrick; Gieseler, Henning

    2011-01-01

    The recent US Food and Drug Administration (FDA) legislation has introduced the evaluation of the Design Space of critical process parameters in manufacturing processes. In freeze-drying, a "formulation" is expected to be robust when minor deviations of the product temperature do not negatively affect the final product quality attributes. To evaluate "formulation" robustness by investigating the effect of elevated product temperature on product quality using a bacterial vaccine solution. The vaccine solution was characterized by freeze-dry microscopy to determine the critical formulation temperature. A conservative cycle was developed using the SMART™ mode of a Lyostar II freeze dryer. Product temperature was elevated to imitate intermediate and aggressive cycle conditions. The final product was analyzed using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Karl Fischer, and modulated differential scanning calorimetry (MDSC), and the life cell count (LCC) during accelerated stability testing. The cakes processed at intermediate and aggressive conditions displayed larger pores with microcollapse of walls and stronger loss in LCC than the conservatively processed product, especially during stability testing. For all process conditions, a loss of the majority of cells was observed during storage. For freeze-drying of life bacterial vaccine solutions, the product temperature profile during primary drying appeared to be inter-related to product quality attributes.

  19. Influence of depressive symptoms on distress related to positive psychotic-like experiences in women.

    Science.gov (United States)

    Brañas, Antía; Barrigón, María Luisa; Lahera, Guillermo; Canal-Rivero, Manuel; Ruiz-Veguilla, Miguel

    2017-12-01

    The Community Assessment of Psychic Experiences (CAPE) is an effective instrument for detection of the presence of psychotic symptoms and associated distress in the general population. However, little research has studied distress associated with positive psychotic-like experiences (PLEs). Our aim is to study PLE-related distress using the CAPE. In this study we analysed factors associated with differences in PLE-related distress in a sample of 200 non-clinical participants recruited by snowball sampling. Presence of PLEs and related psychological distress was measured using the CAPE questionnaire. The influence of age, gender, educational level and drug use was studied. In univariate analysis we found that gender and CAPE positive, depressive and negative scores, were associated with CAPE positive distress. Using multiple linear regression, we found that only the effect of gender, and the interaction between frequency of depression and gender, remained statistically significant. In our sample interaction between gender and depressive symptoms is a determining factor in distress associated with positive PLEs. The results of this study may be useful for the implementation of prevention programs. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Robust transport by multiple motors with nonlinear force–velocity relations and stochastic load sharing

    International Nuclear Information System (INIS)

    Kunwar, Ambarish; Mogilner, Alexander

    2010-01-01

    Transport by processive molecular motors plays an important role in many cell biological phenomena. In many cases, motors work together to transport cargos in the cell, so it is important to understand the mechanics of the multiple motors. Based on earlier modeling efforts, here we study effects of nonlinear force–velocity relations and stochastic load sharing on multiple motor transport. We find that when two or three motors transport the cargo, then the nonlinear and stochastic effects compensate so that the mechanical properties of the transport are robust. Similarly, the transport is insensitive to compliance of the cargo-motor links. Furthermore, the rate of movement against moderate loads is not improved by increasing the small number of motors. When the motor number is greater than 4, correlations between the motors become negligible, and the earlier analytical mean-field theory of the multiple motor transport holds. We predict that the effective diffusion of the cargo driven by the multiple motors under load increases by an order of magnitude compared to that for the single motor. Finally, our simulations predict that the stochastic effects are responsible for a significant dispersion of velocities generated by the 'tug-of-war' of the multiple opposing motors

  1. Neutrality and robustness in evo-devo: emergence of lateral inhibition.

    Directory of Open Access Journals (Sweden)

    Andreea Munteanu

    2008-11-01

    Full Text Available Embryonic development is defined by the hierarchical dynamical process that translates genetic information (genotype into a spatial gene expression pattern (phenotype providing the positional information for the correct unfolding of the organism. The nature and evolutionary implications of genotype-phenotype mapping still remain key topics in evolutionary developmental biology (evo-devo. We have explored here issues of neutrality, robustness, and diversity in evo-devo by means of a simple model of gene regulatory networks. The small size of the system allowed an exhaustive analysis of the entire fitness landscape and the extent of its neutrality. This analysis shows that evolution leads to a class of robust genetic networks with an expression pattern characteristic of lateral inhibition. This class is a repertoire of distinct implementations of this key developmental process, the diversity of which provides valuable clues about its underlying causal principles.

  2. Robustness and structure of complex networks

    Science.gov (United States)

    Shao, Shuai

    This dissertation covers the two major parts of my PhD research on statistical physics and complex networks: i) modeling a new type of attack -- localized attack, and investigating robustness of complex networks under this type of attack; ii) discovering the clustering structure in complex networks and its influence on the robustness of coupled networks. Complex networks appear in every aspect of our daily life and are widely studied in Physics, Mathematics, Biology, and Computer Science. One important property of complex networks is their robustness under attacks, which depends crucially on the nature of attacks and the structure of the networks themselves. Previous studies have focused on two types of attack: random attack and targeted attack, which, however, are insufficient to describe many real-world damages. Here we propose a new type of attack -- localized attack, and study the robustness of complex networks under this type of attack, both analytically and via simulation. On the other hand, we also study the clustering structure in the network, and its influence on the robustness of a complex network system. In the first part, we propose a theoretical framework to study the robustness of complex networks under localized attack based on percolation theory and generating function method. We investigate the percolation properties, including the critical threshold of the phase transition pc and the size of the giant component Pinfinity. We compare localized attack with random attack and find that while random regular (RR) networks are more robust against localized attack, Erdoḧs-Renyi (ER) networks are equally robust under both types of attacks. As for scale-free (SF) networks, their robustness depends crucially on the degree exponent lambda. The simulation results show perfect agreement with theoretical predictions. We also test our model on two real-world networks: a peer-to-peer computer network and an airline network, and find that the real-world networks

  3. Relations among Positive Parenting, parent-child Relationship, and Empathy

    DEFF Research Database (Denmark)

    Wu, Liyun; Zhang, Xingli; Shi, Jiannong

    This study demonstrated relations among 2 features of positive parenting——supportive responsiveness to distress and warmth ,parent-child relationship and empathy.171 children aged 8-10 years (mean age = 9.31 years, 89 girls) participated in the study.In school,participants completed Empathic......,Prosocial Response to Another’s Distress Scale,Parental Acceptance-Rejection Questionnaire, Coping with Children’s Negative Emotions Questionaire,Network of Relationships Inventory. Results showed that: (1)Parents' supportive responsiveness to distress, but not warmth, predicted children's empathy.(2)Near parent-child...... parent-child relationship....

  4. The First Result of Relative Positioning and Velocity Estimation Based on CAPS

    Science.gov (United States)

    Zhao, Jiaojiao; Ge, Jian; Wang, Liang; Wang, Ningbo; Zhou, Kai; Yuan, Hong

    2018-01-01

    The Chinese Area Positioning System (CAPS) is a new positioning system developed by the Chinese Academy of Sciences based on the communication satellites in geosynchronous orbit. The CAPS has been regarded as a pilot system to test the new technology for the design, construction and update of the BeiDou Navigation Satellite System (BDS). The system structure of CAPS, including the space, ground control station and user segments, is almost like the traditional Global Navigation Satellite Systems (GNSSs), but with the clock on the ground, the navigation signal in C waveband, and different principles of operation. The major difference is that the CAPS navigation signal is first generated at the ground control station, before being transmitted to the satellite in orbit and finally forwarded by the communication satellite transponder to the user. This design moves the clock from the satellite in orbit to the ground. The clock error can therefore be easily controlled and mitigated to improve the positioning accuracy. This paper will present the performance of CAPS-based relative positioning and velocity estimation as assessed in Beijing, China. The numerical results show that, (1) the accuracies of relative positioning, using only code measurements, are 1.25 and 1.8 m in the horizontal and vertical components, respectively; (2) meanwhile, they are about 2.83 and 3.15 cm in static mode and 6.31 and 10.78 cm in kinematic mode, respectively, when using the carrier-phase measurements with ambiguities fixed; and (3) the accuracy of the velocity estimation is about 0.04 and 0.11 m/s in static and kinematic modes, respectively. These results indicate the potential application of CAPS for high-precision positioning and velocity estimation and the availability of a new navigation mode based on communication satellites. PMID:29757204

  5. Robustness Recipes for Minimax Robust Optimization in Intensity Modulated Proton Therapy for Oropharyngeal Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Voort, Sebastian van der [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam (Netherlands); Section of Nuclear Energy and Radiation Applications, Department of Radiation, Science and Technology, Delft University of Technology, Delft (Netherlands); Water, Steven van de [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam (Netherlands); Perkó, Zoltán [Section of Nuclear Energy and Radiation Applications, Department of Radiation, Science and Technology, Delft University of Technology, Delft (Netherlands); Heijmen, Ben [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam (Netherlands); Lathouwers, Danny [Section of Nuclear Energy and Radiation Applications, Department of Radiation, Science and Technology, Delft University of Technology, Delft (Netherlands); Hoogeman, Mischa, E-mail: m.hoogeman@erasmusmc.nl [Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam (Netherlands)

    2016-05-01

    Purpose: We aimed to derive a “robustness recipe” giving the range robustness (RR) and setup robustness (SR) settings (ie, the error values) that ensure adequate clinical target volume (CTV) coverage in oropharyngeal cancer patients for given gaussian distributions of systematic setup, random setup, and range errors (characterized by standard deviations of Σ, σ, and ρ, respectively) when used in minimax worst-case robust intensity modulated proton therapy (IMPT) optimization. Methods and Materials: For the analysis, contoured computed tomography (CT) scans of 9 unilateral and 9 bilateral patients were used. An IMPT plan was considered robust if, for at least 98% of the simulated fractionated treatments, 98% of the CTV received 95% or more of the prescribed dose. For fast assessment of the CTV coverage for given error distributions (ie, different values of Σ, σ, and ρ), polynomial chaos methods were used. Separate recipes were derived for the unilateral and bilateral cases using one patient from each group, and all 18 patients were included in the validation of the recipes. Results: Treatment plans for bilateral cases are intrinsically more robust than those for unilateral cases. The required RR only depends on the ρ, and SR can be fitted by second-order polynomials in Σ and σ. The formulas for the derived robustness recipes are as follows: Unilateral patients need SR = −0.15Σ{sup 2} + 0.27σ{sup 2} + 1.85Σ − 0.06σ + 1.22 and RR=3% for ρ = 1% and ρ = 2%; bilateral patients need SR = −0.07Σ{sup 2} + 0.19σ{sup 2} + 1.34Σ − 0.07σ + 1.17 and RR=3% and 4% for ρ = 1% and 2%, respectively. For the recipe validation, 2 plans were generated for each of the 18 patients corresponding to Σ = σ = 1.5 mm and ρ = 0% and 2%. Thirty-four plans had adequate CTV coverage in 98% or more of the simulated fractionated treatments; the remaining 2 had adequate coverage in 97.8% and 97.9%. Conclusions: Robustness recipes were derived that can

  6. Robust automated knowledge capture.

    Energy Technology Data Exchange (ETDEWEB)

    Stevens-Adams, Susan Marie; Abbott, Robert G.; Forsythe, James Chris; Trumbo, Michael Christopher Stefan; Haass, Michael Joseph; Hendrickson, Stacey M. Langfitt

    2011-10-01

    This report summarizes research conducted through the Sandia National Laboratories Robust Automated Knowledge Capture Laboratory Directed Research and Development project. The objective of this project was to advance scientific understanding of the influence of individual cognitive attributes on decision making. The project has developed a quantitative model known as RumRunner that has proven effective in predicting the propensity of an individual to shift strategies on the basis of task and experience related parameters. Three separate studies are described which have validated the basic RumRunner model. This work provides a basis for better understanding human decision making in high consequent national security applications, and in particular, the individual characteristics that underlie adaptive thinking.

  7. Accuracy of velocities from repeated GPS surveys: relative positioning is concerned

    Science.gov (United States)

    Duman, Huseyin; Ugur Sanli, D.

    2016-04-01

    Over more than a decade, researchers have been interested in studying the accuracy of GPS positioning solutions. Recently, reporting the accuracy of GPS velocities has been added to this. Researchers studying landslide motion, tectonic motion, uplift, sea level rise, and subsidence still report results from GPS experiments in which repeated GPS measurements from short sessions are used. This motivated some other researchers to study the accuracy of GPS deformation rates/velocities from various repeated GPS surveys. In one of the efforts, the velocity accuracy was derived from repeated GPS static surveys using short observation sessions and Precise Point Positioning mode of GPS software. Velocities from short GPS sessions were compared with the velocities from 24 h sessions. The accuracy of velocities was obtained using statistical hypothesis testing and quantifying the accuracy of least squares estimation models. The results reveal that 45-60 % of the horizontal and none of the vertical solutions comply with the results from 24 h solutions. We argue that this case in which the data was evaluated using PPP should also apply to the case in which the data belonging to long GPS base lengths is processed using fundamental relative point positioning. To test this idea we chose the two IGS stations ANKR and NICO and derive their velocities from the reference stations held fixed in the stable EURASIAN plate. The University of Bern's GNSS software BERNESE was used to produce relative positioning solutions, and the results are compared with those of GIPSY/OASIS II PPP results. First impressions indicate that it is worth designing a global experiment and test these ideas in detail.

  8. High Frequency Voltage Injection Methods and Observer Design for Initial Position Detection of Permanent Magnet Synchronous Machines

    DEFF Research Database (Denmark)

    Jin, Xinhai; Ni, Ronggang; Chen, Wei

    2018-01-01

    The information of the initial rotor position is essential for smooth start up and robust control of Permanent Magnet Synchronous Machines (PMSMs). RoTating Voltage Injection (RTVI) methods in the stationary reference frame have been commonly adopted to detect the initial rotor position at stands......The information of the initial rotor position is essential for smooth start up and robust control of Permanent Magnet Synchronous Machines (PMSMs). RoTating Voltage Injection (RTVI) methods in the stationary reference frame have been commonly adopted to detect the initial rotor position...

  9. Robust quantum state engineering through coherent localization in biased-coin quantum walks

    Energy Technology Data Exchange (ETDEWEB)

    Majury, Helena [Queen' s University, Centre for Secure Information Technologies (CSIT), Belfast (United Kingdom); Queen' s University, Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Belfast (United Kingdom); Boutari, Joelle [University of Oxford, Clarendon Laboratory, Oxford (United Kingdom); O' Sullivan, Elizabeth [Queen' s University, Centre for Secure Information Technologies (CSIT), Belfast (United Kingdom); Ferraro, Alessandro; Paternostro, Mauro [Queen' s University, Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Belfast (United Kingdom)

    2018-12-15

    We address the performance of a coin-biased quantum walk as a generator for non-classical position states of the walker. We exploit a phenomenon of coherent localization in the position space - resulting from the choice of small values of the coin parameter and assisted by post-selection - to engineer large-size coherent superpositions of position states of the walker. The protocol that we design appears to be remarkably robust against both the actual value taken by the coin parameter and strong dephasing-like noise acting on the spatial degree of freedom. We finally illustrate a possible linear-optics implementation of our proposal, suitable for both bulk and integrated-optics platforms. (orig.)

  10. Investigation of a measure of robustness in inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Makonnen, Yoseif; Beauchemin, Diane

    2015-01-01

    In industrial/commercial settings where operators often have minimal expertise in inductively coupled plasma (ICP) mass spectrometry (MS), there is a prevalent need for a response factor indicating robust plasma conditions, which is analogous to the Mg II/Mg I ratio in ICP optical emission spectrometry (OES), whereby a Mg II/Mg I ratio of 10 constitutes robust conditions. While minimizing the oxide ratio usually corresponds to robust conditions, there is no specific target value that is widely accepted as indicating robust conditions. Furthermore, tuning for low oxide ratios does not necessarily guarantee minimal matrix effects, as they really address polyatomic interferences. From experiments, conducted in parallel for both MS and OES, there were some element pairs of similar mass and very different ionization potential that were exploited for such a purpose, the rationale being that, if these elements were ionized to the same extent, then that could be indicative of a robust plasma. The Be II/Li I intensity ratio was directly related to the Mg II/Mg I ratio in OES. Moreover, the 9Be+/7Li+ ratio was inversely related to the CeO+/Ce+ and LaO+/La+ oxide ratios in MS. The effects of different matrices (i.e. 0.01-0.1 M Na) were also investigated and compared to a conventional argon plasma optimized for maximum sensitivity. The suppression effect of these matrices was significantly reduced, if not eliminated in the case of 0.01 M Na, when the 9Be+/7Li+ ratio was around 0.30 on the Varian 820 MS instrument. Moreover, a very similar ratio (0.28) increased robustness to the same extent on a completely different ICP-MS instrument (PerkinElmer NEXION). Much greater robustness was achieved using a mixed-gas plasma with nitrogen in the outer gas and either nitrogen or hydrogen as a sheathing gas, as the 9Be+/7Li+ ratio was then around 1.70. To the best of our knowledge, this is the first report on using a simple analyte intensity ratio, 9Be+/7Li+, to gauge plasma robustness.

  11. Robust Stability of Scaled-Four-Channel Teleoperation with Internet Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Emma Delgado

    2016-04-01

    Full Text Available We describe the application of a generic stability framework for a teleoperation system under time-varying delay conditions, as addressed in a previous work, to a scaled-four-channel (γ-4C control scheme. Described is how varying delays are dealt with by means of dynamic encapsulation, giving rise to mu-test conditions for robust stability and offering an appealing frequency technique to deal with the stability robustness of the architecture. We discuss ideal transparency problems and we adapt classical solutions so that controllers are proper, without single or double differentiators, and thus avoid the negative effects of noise. The control scheme was fine-tuned and tested for complete stability to zero of the whole state, while seeking a practical solution to the trade-off between stability and transparency in the Internet-based teleoperation. These ideas were tested on an Internet-based application with two Omni devices at remote laboratory locations via simulations and real remote experiments that achieved robust stability, while performing well in terms of position synchronization and force transparency.

  12. Robust Stability of Scaled-Four-Channel Teleoperation with Internet Time-Varying Delays.

    Science.gov (United States)

    Delgado, Emma; Barreiro, Antonio; Falcón, Pablo; Díaz-Cacho, Miguel

    2016-04-26

    We describe the application of a generic stability framework for a teleoperation system under time-varying delay conditions, as addressed in a previous work, to a scaled-four-channel (γ-4C) control scheme. Described is how varying delays are dealt with by means of dynamic encapsulation, giving rise to mu-test conditions for robust stability and offering an appealing frequency technique to deal with the stability robustness of the architecture. We discuss ideal transparency problems and we adapt classical solutions so that controllers are proper, without single or double differentiators, and thus avoid the negative effects of noise. The control scheme was fine-tuned and tested for complete stability to zero of the whole state, while seeking a practical solution to the trade-off between stability and transparency in the Internet-based teleoperation. These ideas were tested on an Internet-based application with two Omni devices at remote laboratory locations via simulations and real remote experiments that achieved robust stability, while performing well in terms of position synchronization and force transparency.

  13. Position detectors, methods of detecting position, and methods of providing positional detectors

    Science.gov (United States)

    Weinberg, David M.; Harding, L. Dean; Larsen, Eric D.

    2002-01-01

    Position detectors, welding system position detectors, methods of detecting various positions, and methods of providing position detectors are described. In one embodiment, a welding system positional detector includes a base that is configured to engage and be moved along a curved surface of a welding work piece. At least one position detection apparatus is provided and is connected with the base and configured to measure angular position of the detector relative to a reference vector. In another embodiment, a welding system positional detector includes a weld head and at least one inclinometer mounted on the weld head. The one inclinometer is configured to develop positional data relative to a reference vector and the position of the weld head on a non-planar weldable work piece.

  14. Walking the cod: an investigation into the relative robustness of cod, Gadus morhua, skeletal elements

    Directory of Open Access Journals (Sweden)

    Andrew K.G. Jones

    1999-12-01

    Full Text Available A simple experiment is described which details what happens to the bones of cod when they are walked on by a man. The pattern of fragmentation for various elements is illustrated and an index of robustness proposed for those elements in a cod skeleton most frequently recovered from archaeological sites.

  15. Robust stabilization control based on guardian maps theory for a longitudinal model of hypersonic vehicle.

    Science.gov (United States)

    Liu, Yanbin; Liu, Mengying; Sun, Peihua

    2014-01-01

    A typical model of hypersonic vehicle has the complicated dynamics such as the unstable states, the nonminimum phases, and the strong coupling input-output relations. As a result, designing a robust stabilization controller is essential to implement the anticipated tasks. This paper presents a robust stabilization controller based on the guardian maps theory for hypersonic vehicle. First, the guardian maps theories are provided to explain the constraint relations between the open subsets of complex plane and the eigenvalues of the state matrix of closed-loop control system. Then, a general control structure in relation to the guardian maps theories is proposed to achieve the respected design demands. Furthermore, the robust stabilization control law depending on the given general control structure is designed for the longitudinal model of hypersonic vehicle. Finally, a simulation example is provided to verify the effectiveness of the proposed methods.

  16. Weighing Efficiency-Robustness in Supply Chain Disruption by Multi-Objective Firefly Algorithm

    Directory of Open Access Journals (Sweden)

    Tong Shu

    2016-03-01

    Full Text Available This paper investigates various supply chain disruptions in terms of scenario planning, including node disruption and chain disruption; namely, disruptions in distribution centers and disruptions between manufacturing centers and distribution centers. Meanwhile, it also focuses on the simultaneous disruption on one node or a number of nodes, simultaneous disruption in one chain or a number of chains and the corresponding mathematical models and exemplification in relation to numerous manufacturing centers and diverse products. Robustness of the design of the supply chain network is examined by weighing efficiency against robustness during supply chain disruptions. Efficiency is represented by operating cost; robustness is indicated by the expected disruption cost and the weighing issue is calculated by the multi-objective firefly algorithm for consistency in the results. It has been shown that the total cost achieved by the optimal target function is lower than that at the most effective time of supply chains. In other words, the decrease of expected disruption cost by improving robustness in supply chains is greater than the increase of operating cost by reducing efficiency, thus leading to cost advantage. Consequently, by approximating the Pareto Front Chart of weighing between efficiency and robustness, enterprises can choose appropriate efficiency and robustness for their longer-term development.

  17. Robust tracking of dexterous continuum robots: Fusing FBG shape sensing and stereo vision.

    Science.gov (United States)

    Rumei Zhang; Hao Liu; Jianda Han

    2017-07-01

    Robust and efficient tracking of continuum robots is important for improving patient safety during space-confined minimally invasive surgery, however, it has been a particularly challenging task for researchers. In this paper, we present a novel tracking scheme by fusing fiber Bragg grating (FBG) shape sensing and stereo vision to estimate the position of continuum robots. Previous visual tracking easily suffers from the lack of robustness and leads to failure, while the FBG shape sensor can only reconstruct the local shape with integral cumulative error. The proposed fusion is anticipated to compensate for their shortcomings and improve the tracking accuracy. To verify its effectiveness, the robots' centerline is recognized by morphology operation and reconstructed by stereo matching algorithm. The shape obtained by FBG sensor is transformed into distal tip position with respect to the camera coordinate system through previously calibrated registration matrices. An experimental platform was set up and repeated tracking experiments were carried out. The accuracy estimated by averaging the absolute positioning errors between shape sensing and stereo vision is 0.67±0.65 mm, 0.41±0.25 mm, 0.72±0.43 mm for x, y and z, respectively. Results indicate that the proposed fusion is feasible and can be used for closed-loop control of continuum robots.

  18. An examination of network position and childhood relational aggression: integrating resource control and social exchange theories.

    Science.gov (United States)

    Neal, Jennifer Watling; Cappella, Elise

    2012-01-01

    Applying resource control theory and social exchange theory, we examined the social network conditions under which elementary age children were likely to engage in relational aggression. Data on classroom peer networks and peer-nominated behaviors were collected on 671 second- through fourth-grade children in 34 urban, low-income classrooms. Nested regression models with robust cluster standard errors demonstrated that the association between children's number of relationships and their levels of relational aggression was moderated by the number of relationships that their affiliates had. Children with more peer relationships (i.e., higher network centrality) exhibited higher levels of relational aggression, but only when these relationships were with peers who had fewer connections themselves (i.e., poorly connected peers). This finding remained significant even when controlling for common predictors of relational aggression including gender, overt aggression, prosocial behavior, victimization, social preference, and perceived popularity. Results are discussed in terms of their implications for advancing the literature on childhood relational aggression and their practical applications for identifying children at risk for these behaviors. © 2012 Wiley Periodicals, Inc.

  19. Optimal interdependence enhances robustness of complex systems

    OpenAIRE

    Singh, R. K.; Sinha, Sitabhra

    2017-01-01

    While interdependent systems have usually been associated with increased fragility, we show that strengthening the interdependence between dynamical processes on different networks can make them more robust. By coupling the dynamics of networks that in isolation exhibit catastrophic collapse with extinction of nodal activity, we demonstrate system-wide persistence of activity for an optimal range of interdependence between the networks. This is related to the appearance of attractors of the g...

  20. A theoretical and practical contribution to supply chain robustness:developing a schema for robustness in dyads

    OpenAIRE

    Durach, Christian F.

    2016-01-01

    Published in print by Universitätsverlag der TU Berlin, ISBN 978-3-7983-2812-9 (ISSN 1865-3170) This doctoral thesis develops four individual research studies on supply chain robustness. The overall goal of these studies is to develop a conceptual framework of supply chain robustness by consolidating current literature in the field, and, drawing on that framework, to construct a schema of determinants that facilitate robustness in buyer-supplier relationships. This research is motivated by...

  1. Guaranteeing robustness of structural condition monitoring to environmental variability

    Science.gov (United States)

    Van Buren, Kendra; Reilly, Jack; Neal, Kyle; Edwards, Harry; Hemez, François

    2017-01-01

    Advances in sensor deployment and computational modeling have allowed significant strides to be recently made in the field of Structural Health Monitoring (SHM). One widely used SHM strategy is to perform a vibration analysis where a model of the structure's pristine (undamaged) condition is compared with vibration response data collected from the physical structure. Discrepancies between model predictions and monitoring data can be interpreted as structural damage. Unfortunately, multiple sources of uncertainty must also be considered in the analysis, including environmental variability, unknown model functional forms, and unknown values of model parameters. Not accounting for these sources of uncertainty can lead to false-positives or false-negatives in the structural condition assessment. To manage the uncertainty, we propose a robust SHM methodology that combines three technologies. A time series algorithm is trained using "baseline" data to predict the vibration response, compare predictions to actual measurements collected on a potentially damaged structure, and calculate a user-defined damage indicator. The second technology handles the uncertainty present in the problem. An analysis of robustness is performed to propagate this uncertainty through the time series algorithm and obtain the corresponding bounds of variation of the damage indicator. The uncertainty description and robustness analysis are both inspired by the theory of info-gap decision-making. Lastly, an appropriate "size" of the uncertainty space is determined through physical experiments performed in laboratory conditions. Our hypothesis is that examining how the uncertainty space changes throughout time might lead to superior diagnostics of structural damage as compared to only monitoring the damage indicator. This methodology is applied to a portal frame structure to assess if the strategy holds promise for robust SHM. (Publication approved for unlimited, public release on October-28

  2. A robust optimization model for blood supply chain in emergency situations

    Directory of Open Access Journals (Sweden)

    Meysam Fereiduni

    2016-09-01

    Full Text Available In this paper, a multi-period model for blood supply chain in emergency situation is presented to optimize decisions related to locate blood facilities and distribute blood products after natural disasters. In disastrous situations, uncertainty is an inseparable part of humanitarian logistics and blood supply chain as well. This paper proposes a robust network to capture the uncertain nature of blood supply chain during and after disasters. This study considers donor points, blood facilities, processing and testing labs, and hospitals as the components of blood supply chain. In addition, this paper makes location and allocation decisions for multiple post disaster periods through real data. The study compares the performances of “p-robust optimization” approach and “robust optimization” approach and the results are discussed.

  3. Approach Motivation as Incentive Salience: Perceptual Sources of Evidence in Relation to Positive Word Primes

    Science.gov (United States)

    Ode, Scott; Winters, Patricia L.; Robinson, Michael D.

    2012-01-01

    Four experiments (total N = 391) examined predictions derived from a biologically-based incentive salience theory of approach motivation. In all experiments, judgments indicative of enhanced perceptual salience were exaggerated in the context of positive, relative to neutral or negative, stimuli. In Experiments 1 and 2, positive words were judged to be of a larger size (Experiment 1) and led individuals to judge subsequently presented neutral objects as larger in size (Experiment 2). In Experiment 3, similar effects were observed in a mock subliminal presentation paradigm. In Experiment 4, positive word primes were perceived to have been presented for a longer duration of time, again relative to both neutral and negative word primes. Results are discussed in relation to theories of approach motivation, affective priming, and the motivation-perception interface. PMID:21875189

  4. ULTOR(Registered TradeMark) Passive Pose and Position Engine For Spacecraft Relative Navigation

    Science.gov (United States)

    Hannah, S. Joel

    2008-01-01

    The ULTOR(Registered TradeMark) Passive Pose and Position Engine (P3E) technology, developed by Advanced Optical Systems, Inc (AOS), uses real-time image correlation to provide relative position and pose data for spacecraft guidance, navigation, and control. Potential data sources include a wide variety of sensors, including visible and infrared cameras. ULTOR(Registered TradeMark) P3E has been demonstrated on a number of host processing platforms. NASA is integrating ULTOR(Registerd TradeMark) P3E into its Relative Navigation System (RNS), which is being developed for the upcoming Hubble Space Telescope (HST) Servicing Mission 4 (SM4). During SM4 ULTOR(Registered TradeMark) P3E will perform realtime pose and position measurements during both the approach and departure phases of the mission. This paper describes the RNS implementation of ULTOR(Registered TradeMark) P3E, and presents results from NASA's hardware-in-the-loop simulation testing against the HST mockup.

  5. The investigation of the relative position of colon and kidney on CT

    International Nuclear Information System (INIS)

    Sadanaga, Masako; Choji, Taku; Nishikawa, Hiroko; Homma, Yuzuru; Sasai, Kazuhiko; Tanaka, Rikuo; Nakada, Taishi; Nakanishi, Takashi.

    1992-01-01

    We investigated the relative position of colon and kidney with CT in 93 male and 92 female patients in various age groups. In Japanese, we thought of little influence of the perinephric fat (Hadar, 1984) or renal fascia (Hopper, 1987) on the variation of these positions. As well, the investigation by CT before uroradiological techniques is much more important than Europeans or Americans, because of the remarkable rate of 'retrorenal colon' was 6.4% on the right and 9.5% on the left in our studies. (author)

  6. How Robust is Your System Resilience?

    Science.gov (United States)

    Homayounfar, M.; Muneepeerakul, R.

    2017-12-01

    Robustness and resilience are concepts in system thinking that have grown in importance and popularity. For many complex social-ecological systems, however, robustness and resilience are difficult to quantify and the connections and trade-offs between them difficult to study. Most studies have either focused on qualitative approaches to discuss their connections or considered only one of them under particular classes of disturbances. In this study, we present an analytical framework to address the linkage between robustness and resilience more systematically. Our analysis is based on a stylized dynamical model that operationalizes a widely used concept framework for social-ecological systems. The model enables us to rigorously define robustness and resilience and consequently investigate their connections. The results reveal the tradeoffs among performance, robustness, and resilience. They also show how the nature of the such tradeoffs varies with the choices of certain policies (e.g., taxation and investment in public infrastructure), internal stresses and external disturbances.

  7. Kinematic parameter calibration method for industrial robot manipulator using the relative position

    International Nuclear Information System (INIS)

    Ha, In Chul

    2008-01-01

    A new calibration method for industrial robot system calibration on a manufacturing floor is presented in this paper. To calibrate the robot system, a laser sensor to measure the distance between robot tool and measurement surface is attached to the robot end-effector and a grid is established in the floor. Given two position command pulses for a robot manipulator and using the position difference between two command pulses, the relative position measurement calibration method will find the real robot kinematic parameters. The procedures developed have been applied to an industrial robot. Finally, the effects of the models used to calibrate the robot are discussed. This calibration method represents an effective, low cost and feasible technique for the industrial robot calibration in lab. projects and industrial environments

  8. Improvement of mechanical robustness of the superhydrophobic wood surface by coating PVA/SiO2 composite polymer

    Science.gov (United States)

    Liu, Feng; Wang, Shuliang; Zhang, Ming; Ma, Miaolian; Wang, Chengyu; Li, Jian

    2013-09-01

    Improvement of the robustness of superhydrophobic surfaces is crucial for the purpose of achieving commercial applications of these surfaces in such various areas as self-cleaning, water repellency and corrosion resistance. We have investigated a fabrication of polyvinyl alcohol (PVA)/silica (SiO2) composite polymer coating on wooden substrates with super repellency toward water, low sliding angles, low contact angle hysteresis, and relatively better mechanical robustness. The composite polymer slurry, consisting of well-mixing SiO2 particles and PVA, is prepared simply and subsequently coated over wooden substrates with good adhesion. In this study, the mechanical robustness of superhydrophobic wood surfaces was evaluated. The effect of petaloid structures of the composite polymer on robustness was investigated using an abrasion test and the results were compared with those of superhydrophobic wood surfaces fabricated by other processes. The produced wood surfaces exhibited promising superhydrophobic properties with a contact angle of 159̊ and a sliding angle of 4̊, and the relatively better mechanical robustness.

  9. Robustness of IPTV business models

    NARCIS (Netherlands)

    Bouwman, H.; Zhengjia, M.; Duin, P. van der; Limonard, S.

    2008-01-01

    The final stage in the STOF method is an evaluation of the robustness of the design, for which the method provides some guidelines. For many innovative services, the future holds numerous uncertainties, which makes evaluating the robustness of a business model a difficult task. In this chapter, we

  10. Robustness and accuracy in sea urchin developmental gene regulatory networks

    Directory of Open Access Journals (Sweden)

    Smadar eBen-Tabou De-Leon

    2016-02-01

    Full Text Available Developmental gene regulatory networks robustly control the timely activation of regulatory and differentiation genes. The structure of these networks underlies their capacity to buffer intrinsic and extrinsic noise and maintain embryonic morphology. Here I illustrate how the use of specific architectures by the sea urchin developmental regulatory networks enables the robust control of cell fate decisions. The Wnt-βcatenin signaling pathway patterns the primary embryonic axis while the BMP signaling pathway patterns the secondary embryonic axis in the sea urchin embryo and across bilateria. Interestingly, in the sea urchin in both cases, the signaling pathway that defines the axis controls directly the expression of a set of downstream regulatory genes. I propose that this direct activation of a set of regulatory genes enables a uniform regulatory response and a clear cut cell fate decision in the endoderm and in the dorsal ectoderm. The specification of the mesodermal pigment cell lineage is activated by Delta signaling that initiates a triple positive feedback loop that locks down the pigment specification state. I propose that the use of compound positive feedback circuitry provides the endodermal cells enough time to turn off mesodermal genes and ensures correct mesoderm vs. endoderm fate decision. Thus, I argue that understanding the control properties of repeatedly used regulatory architectures illuminates their role in embryogenesis and provides possible explanations to their resistance to evolutionary change.

  11. Description and predictors of positive and negative alcohol-related consequences in the first year of college.

    Science.gov (United States)

    Barnett, Nancy P; Clerkin, Elise M; Wood, Mark; Monti, Peter M; O'Leary Tevyaw, Tracy; Corriveau, Donald; Fingeret, Allan; Kahler, Christopher W

    2014-01-01

    The purpose of this study was to establish the frequency of positive and negative alcohol-related consequences during the first year of college and to evaluate gender, race/ethnicity, time of year, alcohol use, and intoxication as predictors of consequences using frequent assessments. Participants (N = 1,053; 57.5% female) completed biweekly assessments of alcohol use and positive and negative alcohol-related consequences throughout the year. The majority of drinkers reported both positive and negative consequences. Having a good time and feeling less stressed were the most commonly reported positive consequences. Blackouts and getting physically sick were the most commonly endorsed negative consequences. At the weekly level, number of drinking days, drinks per drinking day, and estimated blood alcohol concentration (eBAC, reflecting intoxication) were significantly related to all consequences after controlling for demographics and time of year. Negative consequences had stronger associations with number of drinks and eBAC than positive consequences did. With each additional drink consumed on a drinking day, the incidence of negative consequences more than doubled (incidence rate ratio [IRR] = 2.34, 95% CI [2.19, 2.50]), whereas the incidence of positive consequences increased by about half (IRR = 1.51, 95% CI [1.47, 1.56]). The consequence with the largest gender difference was regretted sex, with women reporting it more often. Few racial/ethnic differences were found in report of negative consequences. Greater positive and negative consequences were endorsed at the beginning of both academic semesters. As number of drinks and eBAC increase, the relative odds of a negative consequence are higher than that of a positive consequence. Alcohol interventions could promote greater awareness of the likelihood of specific consequences and could highlight that positive consequences are associated with lower levels of drinking.

  12. The effects of varying contextual demands on age-related positive gaze preferences.

    Science.gov (United States)

    Noh, Soo Rim; Isaacowitz, Derek M

    2015-06-01

    Despite many studies on the age-related positivity effect and its role in visual attention, discrepancies remain regarding whether full attention is required for age-related differences to emerge. The present study took a new approach to this question by varying the contextual demands of emotion processing. This was done by adding perceptual distractions, such as visual and auditory noise, that could disrupt attentional control. Younger and older participants viewed pairs of happy-neutral and fearful-neutral faces while their eye movements were recorded. Facial stimuli were shown either without noise, embedded in a background of visual noise (low, medium, or high), or with simultaneous auditory babble. Older adults showed positive gaze preferences, looking toward happy faces and away from fearful faces; however, their gaze preferences tended to be influenced by the level of visual noise. Specifically, the tendency to look away from fearful faces was not present in conditions with low and medium levels of visual noise but was present when there were high levels of visual noise. It is important to note, however, that in the high-visual-noise condition, external cues were present to facilitate the processing of emotional information. In addition, older adults' positive gaze preferences disappeared or were reduced when they first viewed emotional faces within a distracting context. The current results indicate that positive gaze preferences may be less likely to occur in distracting contexts that disrupt control of visual attention. (c) 2015 APA, all rights reserved.

  13. No evidence of XMRV or related retroviruses in a London HIV-1-positive patient cohort.

    Directory of Open Access Journals (Sweden)

    Eleanor R Gray

    2011-03-01

    Full Text Available Several studies have implicated a recently discovered gammaretrovirus, XMRV (Xenotropic murine leukaemia virus-related virus, in chronic fatigue syndrome and prostate cancer, though whether as causative agent or opportunistic infection is unclear. It has also been suggested that the virus can be found circulating amongst the general population. The discovery has been controversial, with conflicting results from attempts to reproduce the original studies.We extracted peripheral blood DNA from a cohort of 540 HIV-1-positive patients (approximately 20% of whom have never been on anti-retroviral treatment and determined the presence of XMRV and related viruses using TaqMan PCR. While we were able to amplify as few as 5 copies of positive control DNA, we did not find any positive samples in the patient cohort.In view of these negative findings in this highly susceptible group, we conclude that it is unlikely that XMRV or related viruses are circulating at a significant level, if at all, in HIV-1-positive patients in London or in the general population.

  14. Robust Face Recognition Via Gabor Feature and Sparse Representation

    Directory of Open Access Journals (Sweden)

    Hao Yu-Juan

    2016-01-01

    Full Text Available Sparse representation based on compressed sensing theory has been widely used in the field of face recognition, and has achieved good recognition results. but the face feature extraction based on sparse representation is too simple, and the sparse coefficient is not sparse. In this paper, we improve the classification algorithm based on the fusion of sparse representation and Gabor feature, and then improved algorithm for Gabor feature which overcomes the problem of large dimension of the vector dimension, reduces the computation and storage cost, and enhances the robustness of the algorithm to the changes of the environment.The classification efficiency of sparse representation is determined by the collaborative representation,we simplify the sparse constraint based on L1 norm to the least square constraint, which makes the sparse coefficients both positive and reduce the complexity of the algorithm. Experimental results show that the proposed method is robust to illumination, facial expression and pose variations of face recognition, and the recognition rate of the algorithm is improved.

  15. Robust loss functions for boosting.

    Science.gov (United States)

    Kanamori, Takafumi; Takenouchi, Takashi; Eguchi, Shinto; Murata, Noboru

    2007-08-01

    Boosting is known as a gradient descent algorithm over loss functions. It is often pointed out that the typical boosting algorithm, Adaboost, is highly affected by outliers. In this letter, loss functions for robust boosting are studied. Based on the concept of robust statistics, we propose a transformation of loss functions that makes boosting algorithms robust against extreme outliers. Next, the truncation of loss functions is applied to contamination models that describe the occurrence of mislabels near decision boundaries. Numerical experiments illustrate that the proposed loss functions derived from the contamination models are useful for handling highly noisy data in comparison with other loss functions.

  16. Robustness of airline route networks

    Science.gov (United States)

    Lordan, Oriol; Sallan, Jose M.; Escorihuela, Nuria; Gonzalez-Prieto, David

    2016-03-01

    Airlines shape their route network by defining their routes through supply and demand considerations, paying little attention to network performance indicators, such as network robustness. However, the collapse of an airline network can produce high financial costs for the airline and all its geographical area of influence. The aim of this study is to analyze the topology and robustness of the network route of airlines following Low Cost Carriers (LCCs) and Full Service Carriers (FSCs) business models. Results show that FSC hubs are more central than LCC bases in their route network. As a result, LCC route networks are more robust than FSC networks.

  17. Portraying a Positive Image: A Guide to Effective Public Relations for Educational Office Personnel.

    Science.gov (United States)

    Pennsylvania School Boards Association, New Cumberland.

    Suggestions for improving communication and public relations are offered in this guidebook for school office personnel. Because of the high visibility and accessibility of their positions, such staff serve important public relations functions for the school. Chapter 1 examines the public relations role of school office personnel, and chapter 2…

  18. Opportunity's Sol 446 Position, with Relative Heights

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: Coding for Information About Relative Elevations This mosaic of navigation-camera frames from NASA's Mars Exploration Rover Opportunity, presented in a vertical projection, shows the rover's position after it dug itself to wheel-hub depth in a small dune during its 446th martian day, or sol (April 26, 2005). In figure 1, the colors are coding for information about relative elevations in the surrounding area. Red areas are the highest in the image, green areas the lowest. The difference between red and green is about 70 centimeters (28 inches). The elongated dune, or ripple, is about one-third of a meter (one foot) tall and 2.5 meters (8 feet) wide. Opportunity had completed nearly 40 meters (131 feet) of a planned 90-meter (295-foot) drive that sol when its wheels began slipping. The rover was driving backwards at the time. The rover team frequently alternates between backwards and forwards driving to keep wheel lubrication well distributed. The wheels kept rotating enough times to have covered the rest of the distance if they hadn't been slipping, but the rover eventually barely inched forward. After a turn at the end of the planned drive, Opportunity sensed that it had not turned properly and stopped moving. The rover team spent more than a week designing and conducting tests under simulated Mars conditions on Earth before choosing the best way for Opportunity to drive out of the dune.

  19. Visible dormant buds as related to tree diameter and log position

    Science.gov (United States)

    H. Clay Smith

    1967-01-01

    Red oaks and yellow-poplars in a stand of second-growth cove hardwoods in West Virginia were studied to determine whether visible dormant buds are related to tree size or log position. No correlation was found between dormant buds and tree size, for either species; but yellow-poplars had a significantly greater number of buds on the upper log.

  20. High-Efficiency Colloidal Quantum Dot Photovoltaics via Robust Self-Assembled Monolayers

    KAUST Repository

    Kim, Gi-Hwan

    2015-11-11

    © 2015 American Chemical Society. The optoelectronic tunability offered by colloidal quantum dots (CQDs) is attractive for photovoltaic applications but demands proper band alignment at electrodes for efficient charge extraction at minimal cost to voltage. With this goal in mind, self-assembled monolayers (SAMs) can be used to modify interface energy levels locally. However, to be effective SAMs must be made robust to treatment using the various solvents and ligands required for to fabricate high quality CQD solids. We report robust self-assembled monolayers (R-SAMs) that enable us to increase the efficiency of CQD photovoltaics. Only by developing a process for secure anchoring of aromatic SAMs, aided by deposition of the SAMs in a water-free deposition environment, were we able to provide an interface modification that was robust against the ensuing chemical treatments needed in the fabrication of CQD solids. The energy alignment at the rectifying interface was tailored by tuning the R-SAM for optimal alignment relative to the CQD quantum-confined electron energy levels. This resulted in a CQD PV record power conversion efficiency (PCE) of 10.7% with enhanced reproducibility relative to controls.

  1. Multimodel Robust Control for Hydraulic Turbine

    OpenAIRE

    Osuský, Jakub; Števo, Stanislav

    2014-01-01

    The paper deals with the multimodel and robust control system design and their combination based on M-Δ structure. Controller design will be done in the frequency domain with nominal performance specified by phase margin. Hydraulic turbine model is analyzed as system with unstructured uncertainty, and robust stability condition is included in controller design. Multimodel and robust control approaches are presented in detail on hydraulic turbine model. Control design approaches are compared a...

  2. Processing Distracting Non-face Emotional Images: No Evidence of an Age-Related Positivity Effect.

    Science.gov (United States)

    Madill, Mark; Murray, Janice E

    2017-01-01

    Cognitive aging may be accompanied by increased prioritization of social and emotional goals that enhance positive experiences and emotional states. The socioemotional selectivity theory suggests this may be achieved by giving preference to positive information and avoiding or suppressing negative information. Although there is some evidence of a positivity bias in controlled attention tasks, it remains unclear whether a positivity bias extends to the processing of affective stimuli presented outside focused attention. In two experiments, we investigated age-related differences in the effects of to-be-ignored non-face affective images on target processing. In Experiment 1, 27 older (64-90 years) and 25 young adults (19-29 years) made speeded valence judgments about centrally presented positive or negative target images taken from the International Affective Picture System. To-be-ignored distractor images were presented above and below the target image and were either positive, negative, or neutral in valence. The distractors were considered task relevant because they shared emotional characteristics with the target stimuli. Both older and young adults responded slower to targets when distractor valence was incongruent with target valence relative to when distractors were neutral. Older adults responded faster to positive than to negative targets but did not show increased interference effects from positive distractors. In Experiment 2, affective distractors were task irrelevant as the target was a three-digit array and did not share emotional characteristics with the distractors. Twenty-six older (63-84 years) and 30 young adults (18-30 years) gave speeded responses on a digit disparity task while ignoring the affective distractors positioned in the periphery. Task performance in either age group was not influenced by the task-irrelevant affective images. In keeping with the socioemotional selectivity theory, these findings suggest that older adults preferentially

  3. Approach motivation as incentive salience: perceptual sources of evidence in relation to positive word primes.

    Science.gov (United States)

    Ode, Scott; Winters, Patricia L; Robinson, Michael D

    2012-02-01

    Four experiments (total N = 391) examined predictions derived from a biologically based incentive salience theory of approach motivation. In all experiments, judgments indicative of enhanced perceptual salience were exaggerated in the context of positive, relative to neutral or negative, stimuli. In Experiments 1 and 2, positive words were judged to be of a larger size (Experiment 1) and led individuals to judge subsequently presented neutral objects as larger in size (Experiment 2). In Experiment 3, similar effects were observed in a mock subliminal presentation paradigm. In Experiment 4, positive word primes were perceived to have been presented for a longer duration of time, again relative to both neutral and negative word primes. Results are discussed in relation to theories of approach motivation, affective priming, and the motivation-perception interface. PsycINFO Database Record (c) 2012 APA, all rights reserved

  4. Robustness of Linear Systems towards Multi-Dissipative Pertubations

    DEFF Research Database (Denmark)

    Thygesen, Uffe Høgsbro; Poulsen, Niels Kjølstad

    1997-01-01

    We consider the question of robust stability of a linear time invariant plant subject to dynamic perturbations, which are dissipative in the sense of Willems with respect to several quadratic supply rates. For instance, parasitic dynamics are often both small gain and passive. We reduce several...... robustness analysis questions to linear matrix inequalities: robust stability, robust H2 performance and robust performance in presence of disturbances with finite signal-to-noise ratios...

  5. Comparison of beam position calculation methods for application in digital acquisition systems

    Science.gov (United States)

    Reiter, A.; Singh, R.

    2018-05-01

    Different approaches to the data analysis of beam position monitors in hadron accelerators are compared adopting the perspective of an analog-to-digital converter in a sampling acquisition system. Special emphasis is given to position uncertainty and robustness against bias and interference that may be encountered in an accelerator environment. In a time-domain analysis of data in the presence of statistical noise, the position calculation based on the difference-over-sum method with algorithms like signal integral or power can be interpreted as a least-squares analysis of a corresponding fit function. This link to the least-squares method is exploited in the evaluation of analysis properties and in the calculation of position uncertainty. In an analytical model and experimental evaluations the positions derived from a straight line fit or equivalently the standard deviation are found to be the most robust and to offer the least variance. The measured position uncertainty is consistent with the model prediction in our experiment, and the results of tune measurements improve significantly.

  6. A multi-frame particle tracking algorithm robust against input noise

    International Nuclear Information System (INIS)

    Li, Dongning; Zhang, Yuanhui; Sun, Yigang; Yan, Wei

    2008-01-01

    The performance of a particle tracking algorithm which detects particle trajectories from discretely recorded particle positions could be substantially hindered by the input noise. In this paper, a particle tracking algorithm is developed which is robust against input noise. This algorithm employs the regression method instead of the extrapolation method usually employed by existing algorithms to predict future particle positions. If a trajectory cannot be linked to a particle at a frame, the algorithm can still proceed by trying to find a candidate at the next frame. The connectivity of tracked trajectories is inspected to remove the false ones. The algorithm is validated with synthetic data. The result shows that the algorithm is superior to traditional algorithms in the aspect of tracking long trajectories

  7. Robust Nonlinear Control with Compensation Operator for a Peltier System

    Directory of Open Access Journals (Sweden)

    Sheng-Jun Wen

    2014-01-01

    Full Text Available Robust nonlinear control with compensation operator is presented for a Peltier actuated system, where the compensation operator is designed by using a predictive model on heat radiation. For the Peltier system, the heat radiation is related to the fourth power of temperature. So, the heat radiation is affected evidently by the temperature when it is high and temperature difference between the system and environment is large. A new nonlinear model with the heat radiation is set up for the system according to some thermal conduction laws. To ensure robust stability of the nonlinear system, operator based robust right coprime factorization design is considered. Also, a compensation operator based on a predictive model is proposed to cancel effect of the heat radiation, where the predictive model is set up by using radial basis kernel function based SVM (support vector machine method. Finally, simulation results are given to show the effectiveness of the proposed scheme.

  8. Robustness of spin-coupling distributions for perfect quantum state transfer

    International Nuclear Information System (INIS)

    Zwick, Analia; Alvarez, Gonzalo A.; Stolze, Joachim; Osenda, Omar

    2011-01-01

    The transmission of quantum information between different parts of a quantum computer is of fundamental importance. Spin chains have been proposed as quantum channels for transferring information. Different configurations for the spin couplings were proposed in order to optimize the transfer. As imperfections in the creation of these specific spin-coupling distributions can never be completely avoided, it is important to find out which systems are optimally suited for information transfer by assessing their robustness against imperfections or disturbances. We analyze different spin coupling distributions of spin chain channels designed for perfect quantum state transfer. In particular, we study the transfer of an initial state from one end of the chain to the other end. We quantify the robustness of different coupling distributions against perturbations and we relate it to the properties of the energy eigenstates and eigenvalues. We find that the localization properties of the systems play an important role for robust quantum state transfer.

  9. Robust performance results for discrete-time systems

    Directory of Open Access Journals (Sweden)

    Mahmoud Magdi S.

    1997-01-01

    Full Text Available The problems of robust performance and feedback control synthesis for a class of linear discrete-time systems with time-varying parametric uncertainties are addressed in this paper. The uncertainties are bound and have a linear matrix fractional form. Based on the concept of strongly robust H ∞ -performance criterion, results of robust stability and performance are developed and expressed in easily computable linear matrix inequalities. Synthesis of robust feedback controllers is carried out for several system models of interest.

  10. Physics- and engineering knowledge-based geometry repair system for robust parametric CAD geometries

    OpenAIRE

    Li, Dong

    2012-01-01

    In modern multi-objective design optimisation, an effective geometry engine is becoming an essential tool and its performance has a significant impact on the entire process. Building a parametric geometry requires difficult compromises between the conflicting goals of robustness and flexibility. The work presents a solution for improving the robustness of parametric geometry models by capturing and modelling relative engineering knowledge into a surrogate model, and deploying it automatically...

  11. Robust adaptive synchronization of general dynamical networks ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 86; Issue 6. Robust ... A robust adaptive synchronization scheme for these general complex networks with multiple delays and uncertainties is established and raised by employing the robust adaptive control principle and the Lyapunov stability theory. We choose ...

  12. Robust synthesis for real-time systems

    DEFF Research Database (Denmark)

    Larsen, Kim Guldstrand; Legay, Axel; Traonouez, Luois-Marie

    2014-01-01

    Specification theories for real-time systems allow reasoning about interfaces and their implementation models, using a set of operators that includes satisfaction, refinement, logical and parallel composition. To make such theories applicable throughout the entire design process from an abstract...... of introducing small perturbations into formal models. We address this problem of robust implementations in timed specification theories. We first consider a fixed perturbation and study the robustness of timed specifications with respect to the operators of the theory. To this end we synthesize robust...... specification to an implementation, we need to reason about the possibility to effectively implement the theoretical specifications on physical systems, despite their limited precision. In the literature, this implementation problem has been linked to the robustness problem that analyzes the consequences...

  13. Negative and Positive Peer Influence: Relations to Positive and Negative Behaviors for African American, European American, and Hispanic Adolescents

    Science.gov (United States)

    Padilla-Walker, Laura M.; Bean, Roy A.

    2009-01-01

    The purpose of the current study was to examine adolescents' perceptions of negative and positive peer influence (i.e., indirect peer association and direct peer pressure) as they related to adolescent behavior. Regression analyses were conducted using a sample of African American, European American, and Hispanic adolescents (N=1659, M age=16.06,…

  14. Robust H∞ Control for Spacecraft Rendezvous with a Noncooperative Target

    Directory of Open Access Journals (Sweden)

    Shu-Nan Wu

    2013-01-01

    Full Text Available The robust H∞ control for spacecraft rendezvous with a noncooperative target is addressed in this paper. The relative motion of chaser and noncooperative target is firstly modeled as the uncertain system, which contains uncertain orbit parameter and mass. Then the H∞ performance and finite time performance are proposed, and a robust H∞ controller is developed to drive the chaser to rendezvous with the non-cooperative target in the presence of control input saturation, measurement error, and thrust error. The linear matrix inequality technology is used to derive the sufficient condition of the proposed controller. An illustrative example is finally provided to demonstrate the effectiveness of the controller.

  15. Nonlinear Dynamics in Gene Regulation Promote Robustness and Evolvability of Gene Expression Levels.

    Science.gov (United States)

    Steinacher, Arno; Bates, Declan G; Akman, Ozgur E; Soyer, Orkun S

    2016-01-01

    Cellular phenotypes underpinned by regulatory networks need to respond to evolutionary pressures to allow adaptation, but at the same time be robust to perturbations. This creates a conflict in which mutations affecting regulatory networks must both generate variance but also be tolerated at the phenotype level. Here, we perform mathematical analyses and simulations of regulatory networks to better understand the potential trade-off between robustness and evolvability. Examining the phenotypic effects of mutations, we find an inverse correlation between robustness and evolvability that breaks only with nonlinearity in the network dynamics, through the creation of regions presenting sudden changes in phenotype with small changes in genotype. For genotypes embedding low levels of nonlinearity, robustness and evolvability correlate negatively and almost perfectly. By contrast, genotypes embedding nonlinear dynamics allow expression levels to be robust to small perturbations, while generating high diversity (evolvability) under larger perturbations. Thus, nonlinearity breaks the robustness-evolvability trade-off in gene expression levels by allowing disparate responses to different mutations. Using analytical derivations of robustness and system sensitivity, we show that these findings extend to a large class of gene regulatory network architectures and also hold for experimentally observed parameter regimes. Further, the effect of nonlinearity on the robustness-evolvability trade-off is ensured as long as key parameters of the system display specific relations irrespective of their absolute values. We find that within this parameter regime genotypes display low and noisy expression levels. Examining the phenotypic effects of mutations, we find an inverse correlation between robustness and evolvability that breaks only with nonlinearity in the network dynamics. Our results provide a possible solution to the robustness-evolvability trade-off, suggest an explanation for

  16. Nonlinear Dynamics in Gene Regulation Promote Robustness and Evolvability of Gene Expression Levels.

    Directory of Open Access Journals (Sweden)

    Arno Steinacher

    Full Text Available Cellular phenotypes underpinned by regulatory networks need to respond to evolutionary pressures to allow adaptation, but at the same time be robust to perturbations. This creates a conflict in which mutations affecting regulatory networks must both generate variance but also be tolerated at the phenotype level. Here, we perform mathematical analyses and simulations of regulatory networks to better understand the potential trade-off between robustness and evolvability. Examining the phenotypic effects of mutations, we find an inverse correlation between robustness and evolvability that breaks only with nonlinearity in the network dynamics, through the creation of regions presenting sudden changes in phenotype with small changes in genotype. For genotypes embedding low levels of nonlinearity, robustness and evolvability correlate negatively and almost perfectly. By contrast, genotypes embedding nonlinear dynamics allow expression levels to be robust to small perturbations, while generating high diversity (evolvability under larger perturbations. Thus, nonlinearity breaks the robustness-evolvability trade-off in gene expression levels by allowing disparate responses to different mutations. Using analytical derivations of robustness and system sensitivity, we show that these findings extend to a large class of gene regulatory network architectures and also hold for experimentally observed parameter regimes. Further, the effect of nonlinearity on the robustness-evolvability trade-off is ensured as long as key parameters of the system display specific relations irrespective of their absolute values. We find that within this parameter regime genotypes display low and noisy expression levels. Examining the phenotypic effects of mutations, we find an inverse correlation between robustness and evolvability that breaks only with nonlinearity in the network dynamics. Our results provide a possible solution to the robustness-evolvability trade-off, suggest

  17. Uncertain Dynamics, Correlation Effects, and Robust Investment Decisions

    DEFF Research Database (Denmark)

    Flor, Christian Riis; Hesel, Søren

    2015-01-01

    We analyze a firm's investment problem when the dynamics of project value and investment cost are uncertain. We provide an explicit solution using a robust method for an ambiguity averse firm taking this into account. Ambiguity aversion regarding a common risk factor impacts differently than...... ambiguity aversion regarding investment cost residual risk. Correlation between project value and investment cost matters; ambiguity aversion regarding common risk can decrease the investment probability only if correlation is positive. Ambiguity aversion regarding residual risk always increases...... the investment probability. When only project value is risky, volatility can monotonically decrease the investment threshold; this does not hold with the multiple prior method....

  18. Robust Tracking Control for Rendezvous in Near-Circular Orbits

    Directory of Open Access Journals (Sweden)

    Neng Wan

    2013-01-01

    Full Text Available This paper investigates a robust guaranteed cost tracking control problem for thrust-limited spacecraft rendezvous in near-circular orbits. Relative motion model is established based on the two-body problem with noncircularity of the target orbit described as a parameter uncertainty. A guaranteed cost tracking controller with input saturation is designed via a linear matrix inequality (LMI method, and sufficient conditions for the existence of the robust tracking controller are derived, which is more concise and less conservative compared with the previous works. Numerical examples are provided for both time-invariant and time-variant reference signals to illustrate the effectiveness of the proposed control scheme when applied to the terminal rendezvous and other astronautic missions with scheduled states signal.

  19. Further results on "Robust MPC using Linear Matrix Inequalities"

    NARCIS (Netherlands)

    Lazar, M.; Heemels, W.P.M.H.; Munoz de la Pena, D.; Alamo, T.

    2008-01-01

    This paper presents a novel method for designing the terminal cost and the auxiliary control law (ACL) for robust MPC of uncertain linear systems, such that ISS is a priori guaranteed for the closed-loop system. The method is based on the solution of a set of LMIs. An explicit relation is

  20. A Novel Evolutionary Algorithm for Designing Robust Analog Filters

    Directory of Open Access Journals (Sweden)

    Shaobo Li

    2018-03-01

    Full Text Available Designing robust circuits that withstand environmental perturbation and device degradation is critical for many applications. Traditional robust circuit design is mainly done by tuning parameters to improve system robustness. However, the topological structure of a system may set a limit on the robustness achievable through parameter tuning. This paper proposes a new evolutionary algorithm for robust design that exploits the open-ended topological search capability of genetic programming (GP coupled with bond graph modeling. We applied our GP-based robust design (GPRD algorithm to evolve robust lowpass and highpass analog filters. Compared with a traditional robust design approach based on a state-of-the-art real-parameter genetic algorithm (GA, our GPRD algorithm with a fitness criterion rewarding robustness, with respect to parameter perturbations, can evolve more robust filters than what was achieved through parameter tuning alone. We also find that inappropriate GA tuning may mislead the search process and that multiple-simulation and perturbed fitness evaluation methods for evolving robustness have complementary behaviors with no absolute advantage of one over the other.

  1. Robust mechanobiological behavior emerges in heterogeneous myosin systems

    Science.gov (United States)

    Egan, Paul F.; Moore, Jeffrey R.; Ehrlicher, Allen J.; Weitz, David A.; Schunn, Christian; Cagan, Jonathan; LeDuc, Philip

    2017-09-01

    Biological complexity presents challenges for understanding natural phenomenon and engineering new technologies, particularly in systems with molecular heterogeneity. Such complexity is present in myosin motor protein systems, and computational modeling is essential for determining how collective myosin interactions produce emergent system behavior. We develop a computational approach for altering myosin isoform parameters and their collective organization, and support predictions with in vitro experiments of motility assays with α-actinins as molecular force sensors. The computational approach models variations in single myosin molecular structure, system organization, and force stimuli to predict system behavior for filament velocity, energy consumption, and robustness. Robustness is the range of forces where a filament is expected to have continuous velocity and depends on used myosin system energy. Myosin systems are shown to have highly nonlinear behavior across force conditions that may be exploited at a systems level by combining slow and fast myosin isoforms heterogeneously. Results suggest some heterogeneous systems have lower energy use near stall conditions and greater energy consumption when unloaded, therefore promoting robustness. These heterogeneous system capabilities are unique in comparison with homogenous systems and potentially advantageous for high performance bionanotechnologies. Findings open doors at the intersections of mechanics and biology, particularly for understanding and treating myosin-related diseases and developing approaches for motor molecule-based technologies.

  2. Modeling stochasticity and robustness in gene regulatory networks.

    Science.gov (United States)

    Garg, Abhishek; Mohanram, Kartik; Di Cara, Alessandro; De Micheli, Giovanni; Xenarios, Ioannis

    2009-06-15

    Understanding gene regulation in biological processes and modeling the robustness of underlying regulatory networks is an important problem that is currently being addressed by computational systems biologists. Lately, there has been a renewed interest in Boolean modeling techniques for gene regulatory networks (GRNs). However, due to their deterministic nature, it is often difficult to identify whether these modeling approaches are robust to the addition of stochastic noise that is widespread in gene regulatory processes. Stochasticity in Boolean models of GRNs has been addressed relatively sparingly in the past, mainly by flipping the expression of genes between different expression levels with a predefined probability. This stochasticity in nodes (SIN) model leads to over representation of noise in GRNs and hence non-correspondence with biological observations. In this article, we introduce the stochasticity in functions (SIF) model for simulating stochasticity in Boolean models of GRNs. By providing biological motivation behind the use of the SIF model and applying it to the T-helper and T-cell activation networks, we show that the SIF model provides more biologically robust results than the existing SIN model of stochasticity in GRNs. Algorithms are made available under our Boolean modeling toolbox, GenYsis. The software binaries can be downloaded from http://si2.epfl.ch/ approximately garg/genysis.html.

  3. Self-reported oral and general health in relation to socioeconomic position.

    Science.gov (United States)

    Hakeberg, Magnus; Wide Boman, Ulla

    2017-07-26

    During the past two decades, several scientific publications from different countries have shown how oral health in the population varies with social determinants. The aim of the present study was to explore the relationship between self-reported oral and general health in relation to different measures of socioeconomic position. Data were collected from a randomly selected sample of the adult population in Sweden (n = 3500, mean age 53.4 years, 53.1% women). The response rate was 49.7%. Subjects were interviewed by telephone, using a questionnaire including items on self-reported oral and general health, socioeconomic position and lifestyle. A significant gradient was found for both oral and general health: the lower the socioeconomic position, the poorer the health. Socioeconomic position and, above all, economic measures were strongly associated with general health (OR 3.95) and with oral health (OR 1.76) if having an income below SEK 200,000 per year. Similar results were found in multivariate analyses controlling for age, gender and lifestyle variables. For adults, there are clear socioeconomic gradients in self-reported oral and general health, irrespective of different socioeconomic measures. Action is needed to ensure greater equity of oral and general health.

  4. REINA at CLEF 2007 Robust Task

    OpenAIRE

    Zazo Rodríguez, Ángel Francisco; Figuerola, Carlos G.; Alonso Berrocal, José Luis

    2007-01-01

    This paper describes our work at CLEF 2007 Robust Task. We have participated in the monolingual (English, French and Portuguese) and the bilingual (English to French) subtask. At CLEF 2006 our research group obtained very good results applying local query expansion using windows of terms in the robust task. This year we have used the same expansion technique, but taking into account some criteria of robustness: MAP, GMAP, MMR, GS@10, P@10, number of failed topics, number of topics bellow 0.1 ...

  5. Machine learning meliorates computing and robustness in discrete combinatorial optimization problems.

    Directory of Open Access Journals (Sweden)

    Fushing Hsieh

    2016-11-01

    Full Text Available Discrete combinatorial optimization problems in real world are typically defined via an ensemble of potentially high dimensional measurements pertaining to all subjects of a system under study. We point out that such a data ensemble in fact embeds with system's information content that is not directly used in defining the combinatorial optimization problems. Can machine learning algorithms extract such information content and make combinatorial optimizing tasks more efficient? Would such algorithmic computations bring new perspectives into this classic topic of Applied Mathematics and Theoretical Computer Science? We show that answers to both questions are positive. One key reason is due to permutation invariance. That is, the data ensemble of subjects' measurement vectors is permutation invariant when it is represented through a subject-vs-measurement matrix. An unsupervised machine learning algorithm, called Data Mechanics (DM, is applied to find optimal permutations on row and column axes such that the permuted matrix reveals coupled deterministic and stochastic structures as the system's information content. The deterministic structures are shown to facilitate geometry-based divide-and-conquer scheme that helps optimizing task, while stochastic structures are used to generate an ensemble of mimicries retaining the deterministic structures, and then reveal the robustness pertaining to the original version of optimal solution. Two simulated systems, Assignment problem and Traveling Salesman problem, are considered. Beyond demonstrating computational advantages and intrinsic robustness in the two systems, we propose brand new robust optimal solutions. We believe such robust versions of optimal solutions are potentially more realistic and practical in real world settings.

  6. The Variation Management Framework (VMF) for Robust Design

    DEFF Research Database (Denmark)

    Howard, Thomas J.; Ebro, Martin; Eifler, Tobias

    2014-01-01

    Robust Design is an approach to reduce the effects of variation. There are numerous tools,methods and models associated with robust design, however, there is both a lack of a processmodel formalising the step of a robust design process and a framework tying the models together.In this paper we pr...... in the market place and identifies areaswhere action can be taken against variation. An additional benefit of the framework is that itmakes the link between visual/sensory/perceptual robustness, product robustness, and productionvariation (Six Sigma)....

  7. Review: Deciphering animal robustness. A synthesis to facilitate its use in livestock breeding and management.

    Science.gov (United States)

    Friggens, N C; Blanc, F; Berry, D P; Puillet, L

    2017-12-01

    As the environments in which livestock are reared become more variable, animal robustness becomes an increasingly valuable attribute. Consequently, there is increasing focus on managing and breeding for it. However, robustness is a difficult phenotype to properly characterise because it is a complex trait composed of multiple components, including dynamic elements such as the rates of response to, and recovery from, environmental perturbations. In this review, the following definition of robustness is used: the ability, in the face of environmental constraints, to carry on doing the various things that the animal needs to do to favour its future ability to reproduce. The different elements of this definition are discussed to provide a clearer understanding of the components of robustness. The implications for quantifying robustness are that there is no single measure of robustness but rather that it is the combination of multiple and interacting component mechanisms whose relative value is context dependent. This context encompasses both the prevailing environment and the prevailing selection pressure. One key issue for measuring robustness is to be clear on the use to which the robustness measurements will employed. If the purpose is to identify biomarkers that may be useful for molecular phenotyping or genotyping, the measurements should focus on the physiological mechanisms underlying robustness. However, if the purpose of measuring robustness is to quantify the extent to which animals can adapt to limiting conditions then the measurements should focus on the life functions, the trade-offs between them and the animal's capacity to increase resource acquisition. The time-related aspect of robustness also has important implications. Single time-point measurements are of limited value because they do not permit measurement of responses to (and recovery from) environmental perturbations. The exception being single measurements of the accumulated consequence of a

  8. Measure of robustness for complex networks

    Science.gov (United States)

    Youssef, Mina Nabil

    Critical infrastructures are repeatedly attacked by external triggers causing tremendous amount of damages. Any infrastructure can be studied using the powerful theory of complex networks. A complex network is composed of extremely large number of different elements that exchange commodities providing significant services. The main functions of complex networks can be damaged by different types of attacks and failures that degrade the network performance. These attacks and failures are considered as disturbing dynamics, such as the spread of viruses in computer networks, the spread of epidemics in social networks, and the cascading failures in power grids. Depending on the network structure and the attack strength, every network differently suffers damages and performance degradation. Hence, quantifying the robustness of complex networks becomes an essential task. In this dissertation, new metrics are introduced to measure the robustness of technological and social networks with respect to the spread of epidemics, and the robustness of power grids with respect to cascading failures. First, we introduce a new metric called the Viral Conductance (VCSIS ) to assess the robustness of networks with respect to the spread of epidemics that are modeled through the susceptible/infected/susceptible (SIS) epidemic approach. In contrast to assessing the robustness of networks based on a classical metric, the epidemic threshold, the new metric integrates the fraction of infected nodes at steady state for all possible effective infection strengths. Through examples, VCSIS provides more insights about the robustness of networks than the epidemic threshold. In addition, both the paradoxical robustness of Barabasi-Albert preferential attachment networks and the effect of the topology on the steady state infection are studied, to show the importance of quantifying the robustness of networks. Second, a new metric VCSIR is introduced to assess the robustness of networks with respect

  9. STEGO TRANSFORMATION OF SPATIAL DOMAIN OF COVER IMAGE ROBUST AGAINST ATTACKS ON EMBEDDED MESSAGE

    Directory of Open Access Journals (Sweden)

    Kobozeva A.

    2014-04-01

    Full Text Available One of the main requirements to steganografic algorithm to be developed is robustness against disturbing influences, that is, to attacks against the embedded message. It was shown that guaranteeing the stego algorithm robustness does not depend on whether the additional information is embedded into the spatial or transformation domain of the cover image. Given the existing advantages of the spatial domain of the cover image in organization of embedding and extracting processes, a sufficient condition for ensuring robustness of such stego transformation was obtained in this work. It was shown that the amount of brightness correction related to the pixels of the cover image block is similar to the amount of correction related to the maximum singular value of the corresponding matrix of the block in case of embedding additional data that ensures robustness against attacks on the embedded message. Recommendations were obtained for selecting the size of the cover image block used in stego transformation as one of the parameters determining the calculation error of stego message. Given the inversely correspondence between the stego capacity of the stego channel being organized and the size of the cover image block, l=8 value was recommended.

  10. A Hybrid Interval-Robust Optimization Model for Water Quality Management.

    Science.gov (United States)

    Xu, Jieyu; Li, Yongping; Huang, Guohe

    2013-05-01

    In water quality management problems, uncertainties may exist in many system components and pollution-related processes ( i.e. , random nature of hydrodynamic conditions, variability in physicochemical processes, dynamic interactions between pollutant loading and receiving water bodies, and indeterminacy of available water and treated wastewater). These complexities lead to difficulties in formulating and solving the resulting nonlinear optimization problems. In this study, a hybrid interval-robust optimization (HIRO) method was developed through coupling stochastic robust optimization and interval linear programming. HIRO can effectively reflect the complex system features under uncertainty, where implications of water quality/quantity restrictions for achieving regional economic development objectives are studied. By delimiting the uncertain decision space through dimensional enlargement of the original chemical oxygen demand (COD) discharge constraints, HIRO enhances the robustness of the optimization processes and resulting solutions. This method was applied to planning of industry development in association with river-water pollution concern in New Binhai District of Tianjin, China. Results demonstrated that the proposed optimization model can effectively communicate uncertainties into the optimization process and generate a spectrum of potential inexact solutions supporting local decision makers in managing benefit-effective water quality management schemes. HIRO is helpful for analysis of policy scenarios related to different levels of economic penalties, while also providing insight into the tradeoff between system benefits and environmental requirements.

  11. A Hybrid Interval–Robust Optimization Model for Water Quality Management

    Science.gov (United States)

    Xu, Jieyu; Li, Yongping; Huang, Guohe

    2013-01-01

    Abstract In water quality management problems, uncertainties may exist in many system components and pollution-related processes (i.e., random nature of hydrodynamic conditions, variability in physicochemical processes, dynamic interactions between pollutant loading and receiving water bodies, and indeterminacy of available water and treated wastewater). These complexities lead to difficulties in formulating and solving the resulting nonlinear optimization problems. In this study, a hybrid interval–robust optimization (HIRO) method was developed through coupling stochastic robust optimization and interval linear programming. HIRO can effectively reflect the complex system features under uncertainty, where implications of water quality/quantity restrictions for achieving regional economic development objectives are studied. By delimiting the uncertain decision space through dimensional enlargement of the original chemical oxygen demand (COD) discharge constraints, HIRO enhances the robustness of the optimization processes and resulting solutions. This method was applied to planning of industry development in association with river-water pollution concern in New Binhai District of Tianjin, China. Results demonstrated that the proposed optimization model can effectively communicate uncertainties into the optimization process and generate a spectrum of potential inexact solutions supporting local decision makers in managing benefit-effective water quality management schemes. HIRO is helpful for analysis of policy scenarios related to different levels of economic penalties, while also providing insight into the tradeoff between system benefits and environmental requirements. PMID:23922495

  12. Recall of briefly presented chess positions and its relation to chess skill.

    Directory of Open Access Journals (Sweden)

    Yanfei Gong

    Full Text Available Individual differences in memory performance in a domain of expertise have traditionally been accounted for by previously acquired chunks of knowledge and patterns. These accounts have been examined experimentally mainly in chess. The role of chunks (clusters of chess pieces recalled in rapid succession during recall of chess positions and their relations to chess skill are, however, under debate. By introducing an independent chunk-identification technique, namely repeated-recall technique, this study identified individual chunks for particular chess players. The study not only tested chess players with increasing chess expertise, but also tested non-chess players who should not have previously acquired any chess related chunks in memory. For recall of game positions significant differences between players and non-players were found in virtually all the characteristics of chunks recalled. Size of the largest chunks also correlates with chess skill within the group of rated chess players. Further research will help us understand how these memory encodings can explain large differences in chess skill.

  13. Recall of briefly presented chess positions and its relation to chess skill.

    Science.gov (United States)

    Gong, Yanfei; Ericsson, K Anders; Moxley, Jerad H

    2015-01-01

    Individual differences in memory performance in a domain of expertise have traditionally been accounted for by previously acquired chunks of knowledge and patterns. These accounts have been examined experimentally mainly in chess. The role of chunks (clusters of chess pieces recalled in rapid succession during recall of chess positions) and their relations to chess skill are, however, under debate. By introducing an independent chunk-identification technique, namely repeated-recall technique, this study identified individual chunks for particular chess players. The study not only tested chess players with increasing chess expertise, but also tested non-chess players who should not have previously acquired any chess related chunks in memory. For recall of game positions significant differences between players and non-players were found in virtually all the characteristics of chunks recalled. Size of the largest chunks also correlates with chess skill within the group of rated chess players. Further research will help us understand how these memory encodings can explain large differences in chess skill.

  14. Molecular marker differences relate to developmental position and subsets of mesodiencephalic dopaminergic neurons.

    Directory of Open Access Journals (Sweden)

    Simone M Smits

    Full Text Available The development of mesodiencephalic dopaminergic (mdDA neurons located in the substantia nigra compacta (SNc and ventral tegmental area (VTA follow a number of stages marked by distinct events. After preparation of the region by signals that provide induction and patterning, several transcription factors have been identified, which are involved in specifying the neuronal fate of these cells. The specific vulnerability of SNc neurons is thought to root in these specific developmental programs. The present study examines the positions of young postmitotic mdDA neurons to relate developmental position to mdDA subset specific markers. MdDA neurons were mapped relative to the neuromeric domains (prosomeres 1-3 (P1-3, midbrain, and hindbrain as well as the longitudinal subdivisions (floor plate, basal plate, alar plate, as proposed by the prosomeric model. We found that postmitotic mdDA neurons are located mainly in the floorplate domain and very few in slightly more lateral domains. Moreover, mdDA neurons are present along a large proportion of the anterior/posterior axis extending from the midbrain to P3 in the diencephalon. The specific positions relate to some extent to the presence of specific subset markers as Ahd2. In the adult stage more of such subsets specific expressed genes are present and may represent a molecular map defining molecularly distinct groups of mdDA neurons.

  15. Robust recognition via information theoretic learning

    CERN Document Server

    He, Ran; Yuan, Xiaotong; Wang, Liang

    2014-01-01

    This Springer Brief represents a comprehensive review of information theoretic methods for robust recognition. A variety of information theoretic methods have been proffered in the past decade, in a large variety of computer vision applications; this work brings them together, attempts to impart the theory, optimization and usage of information entropy.The?authors?resort to a new information theoretic concept, correntropy, as a robust measure and apply it to solve robust face recognition and object recognition problems. For computational efficiency,?the brief?introduces the additive and multip

  16. Robust methods for multivariate data analysis A1

    DEFF Research Database (Denmark)

    Frosch, Stina; Von Frese, J.; Bro, Rasmus

    2005-01-01

    Outliers may hamper proper classical multivariate analysis, and lead to incorrect conclusions. To remedy the problem of outliers, robust methods are developed in statistics and chemometrics. Robust methods reduce or remove the effect of outlying data points and allow the ?good? data to primarily...... determine the result. This article reviews the most commonly used robust multivariate regression and exploratory methods that have appeared since 1996 in the field of chemometrics. Special emphasis is put on the robust versions of chemometric standard tools like PCA and PLS and the corresponding robust...

  17. Robust balancing and position control of a single spherical wheeled mobile platform

    OpenAIRE

    Yavuz, Fırat; Yavuz, Firat; Ünel, Mustafa; Unel, Mustafa

    2016-01-01

    Self-balancing mobile platforms with single spherical wheel, generally called ballbots, are suitable example of underactuated systems. Balancing control of a ballbot platform, which aims to maintain the upright orientation by rejecting external disturbances, is important during station keeping or trajectory tracking. In this paper, acceleration based balancing and position control of a single spherical wheeled mobile platform that has three single-row omniwheel drive m...

  18. Robustness Evaluation of Timber Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2009-01-01

    Robustness of structural systems has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure.......Robustness of structural systems has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure....

  19. Ins-Robust Primitive Words

    OpenAIRE

    Srivastava, Amit Kumar; Kapoor, Kalpesh

    2017-01-01

    Let Q be the set of primitive words over a finite alphabet with at least two symbols. We characterize a class of primitive words, Q_I, referred to as ins-robust primitive words, which remain primitive on insertion of any letter from the alphabet and present some properties that characterizes words in the set Q_I. It is shown that the language Q_I is dense. We prove that the language of primitive words that are not ins-robust is not context-free. We also present a linear time algorithm to reco...

  20. Robust Identification of Developmentally Active Endothelial Enhancers in Zebrafish Using FANS-Assisted ATAC-Seq.

    Science.gov (United States)

    Quillien, Aurelie; Abdalla, Mary; Yu, Jun; Ou, Jianhong; Zhu, Lihua Julie; Lawson, Nathan D

    2017-07-18

    Identification of tissue-specific and developmentally active enhancers provides insights into mechanisms that control gene expression during embryogenesis. However, robust detection of these regulatory elements remains challenging, especially in vertebrate genomes. Here, we apply fluorescent-activated nuclei sorting (FANS) followed by Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) to identify developmentally active endothelial enhancers in the zebrafish genome. ATAC-seq of nuclei from Tg(fli1a:egfp) y1 transgenic embryos revealed expected patterns of nucleosomal positioning at transcriptional start sites throughout the genome and association with active histone modifications. Comparison of ATAC-seq from GFP-positive and -negative nuclei identified more than 5,000 open elements specific to endothelial cells. These elements flanked genes functionally important for vascular development and that displayed endothelial-specific gene expression. Importantly, a majority of tested elements drove endothelial gene expression in zebrafish embryos. Thus, FANS-assisted ATAC-seq using transgenic zebrafish embryos provides a robust approach for genome-wide identification of active tissue-specific enhancer elements. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  1. WHAT POPS OUT IN POSITIONAL PRIMING OF POP-OUT: INSIGHTS FROM EVENT-RELATED EEG LATERALIZATIONS

    Directory of Open Access Journals (Sweden)

    Ahu eGokce

    2014-07-01

    Full Text Available It is well established that, in visual pop-out search, reaction time (RT performance is influenced by cross-trial repetitions versus changes of target-defining attributes. One instance of this is referred to as ‘positional priming of pop-out (pPoP’ (Maljkovic & Nakayama, 1996. In positional PoP paradigms, the processing of the current target is examined depending on whether it occurs at the previous target or a previous distractor location, relative to a previously empty location (‘neutral’ baseline, permitting target facilitation and distractor inhibition to be dissociated. The present study combined RT measures with specific sensory- and motor-driven event-related lateralizations to track the time course of four distinct processing levels as a function of the target’s position across consecutive trials. The results showed that, relative to targets at previous target and ‘neutral’ locations, the appearance of a target at a previous distractor location was associated with a delayed build-up of the PCN wave, indicating that distractor positions are suppressed at early stages of visual processing. By contrast, presentation of a target at a previous target, relative to ‘neutral’ and distractor locations, modulated the elicitation of the subsequent sLRP wave, indicating that post-selective response selection is facilitated if the target occurred at the same position as on the previous trial. Overall, the results of present study provides electrophysiological evidence for the idea that target location priming (RT benefits does not originate from an enhanced coding of target saliency at repeated (target locations; instead, they arise (near- exclusively from processing levels subsequent to focal-attentional target selection.

  2. Robustness and Vulnerability of Networks with Dynamical Dependency Groups.

    Science.gov (United States)

    Bai, Ya-Nan; Huang, Ning; Wang, Lei; Wu, Zhi-Xi

    2016-11-28

    The dependency property and self-recovery of failure nodes both have great effects on the robustness of networks during the cascading process. Existing investigations focused mainly on the failure mechanism of static dependency groups without considering the time-dependency of interdependent nodes and the recovery mechanism in reality. In this study, we present an evolving network model consisting of failure mechanisms and a recovery mechanism to explore network robustness, where the dependency relations among nodes vary over time. Based on generating function techniques, we provide an analytical framework for random networks with arbitrary degree distribution. In particular, we theoretically find that an abrupt percolation transition exists corresponding to the dynamical dependency groups for a wide range of topologies after initial random removal. Moreover, when the abrupt transition point is above the failure threshold of dependency groups, the evolving network with the larger dependency groups is more vulnerable; when below it, the larger dependency groups make the network more robust. Numerical simulations employing the Erdős-Rényi network and Barabási-Albert scale free network are performed to validate our theoretical results.

  3. Robust sawtooth period control based on adaptive online optimization

    International Nuclear Information System (INIS)

    Bolder, J.J.; Witvoet, G.; De Baar, M.R.; Steinbuch, M.; Van de Wouw, N.; Haring, M.A.M.; Westerhof, E.; Doelman, N.J.

    2012-01-01

    The systematic design of a robust adaptive control strategy for the sawtooth period using electron cyclotron current drive (ECCD) is presented. Recent developments in extremum seeking control (ESC) are employed to derive an optimized controller structure and offer practical tuning guidelines for its parameters. In this technique a cost function in terms of the desired sawtooth period is optimized online by changing the ECCD deposition location based on online estimations of the gradient of the cost function. The controller design does not require a detailed model of the sawtooth instability. Therefore, the proposed ESC is widely applicable to any sawtoothing plasma or plasma simulation and is inherently robust against uncertainties or plasma variations. Moreover, it can handle a broad class of disturbances. This is demonstrated by time-domain simulations, which show successful tracking of time-varying sawtooth period references throughout the whole operating space, even in the presence of variations in plasma parameters, disturbances and slow launcher mirror dynamics. Due to its simplicity and robustness the proposed ESC is a valuable sawtooth control candidate for any experimental tokamak plasma, and may even be applicable to other fusion-related control problems. (paper)

  4. A Survey on Robustness in Railway Planning

    DEFF Research Database (Denmark)

    Lusby, Richard Martin; Larsen, Jesper; Bull, Simon Henry

    2018-01-01

    Planning problems in passenger railway range from long term strategic decision making to the detailed planning of operations.Operations research methods have played an increasing role in this planning process. However, recently more attention has been given to considerations of robustness...... in the quality of solutions to individual planning problems, and of operations in general. Robustness in general is the capacity for some system to absorb or resist changes. In the context of railway robustness it is often taken to be the capacity for operations to continue at some level when faced...... with a disruption such as delay or failure. This has resulted in more attention given to the inclusion of robustness measures and objectives in individual planning problems, and to the providing of tools to ensure operations continue under disrupted situations. In this paper we survey the literature on robustness...

  5. Robust Clamping Force Control of an Electro-Mechanical Brake System for Application to Commercial City Buses

    Directory of Open Access Journals (Sweden)

    Sangjune Eum

    2017-02-01

    Full Text Available This paper proposes a sensor-less robust force control method for improving the control performance of an electro-mechanical brake (EMB which is applicable to commercial city buses. The EMB generates the accurate clamping force commanded by a driver through an independent motor control at each wheel instead of using existing mechanical components. In general, an EMB undergoes parameter variation and a backdrivability problem. For this reason, the cascade control strategy (e.g., force-position cascade control structure is proposed and the disturbance observer is employed to enhance control robustness against model variations. Additionally, this paper proposed the clamping force estimation method for a sensor-less control, i.e., the clamping force observer (CFO. Finally, in order to confirm the performance and effectiveness of a proposed robust control method, several experiments are performed and analyzed.

  6. A robust interpretation of duration calculus

    DEFF Research Database (Denmark)

    Franzle, M.; Hansen, Michael Reichhardt

    2005-01-01

    We transfer the concept of robust interpretation from arithmetic first-order theories to metric-time temporal logics. The idea is that the interpretation of a formula is robust iff its truth value does not change under small variation of the constants in the formula. Exemplifying this on Duration...... Calculus (DC), our findings are that the robust interpretation of DC is equivalent to a multi-valued interpretation that uses the real numbers as semantic domain and assigns Lipschitz-continuous interpretations to all operators of DC. Furthermore, this continuity permits approximation between discrete...

  7. Design Robust Controller for Rotary Kiln

    Directory of Open Access Journals (Sweden)

    Omar D. Hernández-Arboleda

    2013-11-01

    Full Text Available This paper presents the design of a robust controller for a rotary kiln. The designed controller is a combination of a fractional PID and linear quadratic regulator (LQR, these are not used to control the kiln until now, in addition robustness criteria are evaluated (gain margin, phase margin, strength gain, rejecting high frequency noise and sensitivity applied to the entire model (controller-plant, obtaining good results with a frequency range of 0.020 to 90 rad/s, which contributes to the robustness of the system.

  8. Danish Requirements for Robustness of Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Christensen, H. H.

    2006-01-01

    . This paper describes the background of the revised robustness requirements implemented in the Danish Code of Practice for Safety of Structures in 2003 [1, 2, 3]. According to the Danish design rules robustness shall be documented for all structures where consequences of failure are serious. This paper...... describes the background of the design procedure in the Danish codes, which shall be followed in order to document sufficient robustness in the following steps: Step 1: review of loads and possible failure modes/scenarios and determination of acceptable collapse extent. Step 2: review of the structural...

  9. Robust lyapunov controller for uncertain systems

    KAUST Repository

    Laleg-Kirati, Taous-Meriem; Elmetennani, Shahrazed

    2017-01-01

    Various examples of systems and methods are provided for Lyapunov control for uncertain systems. In one example, a system includes a process plant and a robust Lyapunov controller configured to control an input of the process plant. The robust

  10. CALiPER Report 20.3: Robustness of LED PAR38 Lamps

    Energy Technology Data Exchange (ETDEWEB)

    Poplawski, Michael E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Royer, Michael P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Brown, Charles C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-12-01

    Three samples of 40 of the Series 20 PAR38 lamps underwent multi-stress testing, whereby samples were subjected to increasing levels of simultaneous thermal, humidity, electrical, and vibrational stress. The results do not explicitly predict expected lifetime or reliability, but they can be compared with one another, as well as with benchmark conventional products, to assess the relative robustness of the product designs. On average, the 32 LED lamp models tested were substantially more robust than the conventional benchmark lamps. As with other performance attributes, however, there was great variability in the robustness and design maturity of the LED lamps. Several LED lamp samples failed within the first one or two levels of the ten-level stress plan, while all three samples of some lamp models completed all ten levels. One potential area of improvement is design maturity, given that more than 25% of the lamp models demonstrated a difference in failure level for the three samples that was greater than or equal to the maximum for the benchmarks. At the same time, the fact that nearly 75% of the lamp models exhibited better design maturity than the benchmarks is noteworthy, given the relative stage of development for the technology.

  11. Robustness evaluation of cutting tool maintenance planning for soft ground tunneling projects

    Directory of Open Access Journals (Sweden)

    Alena Conrads

    2018-03-01

    Full Text Available Tunnel boring machines require extensive maintenance and inspection effort to provide a high availability. The cutting tools of the cutting wheel must be changed timely upon reaching a critical condition. While one possible maintenance strategy is to change tools only when it is absolutely necessary, tools can also be changed preventively to avoid further damages. Such different maintenance strategies influence the maintenance duration and the overall project performance. However, determine downtime related to a particular maintenance strategy is still a challenging task. This paper shows an analysis of the robustness to achieve the planned project performance of a maintenance strategy considering uncertainties of wear behavior of the cutting tools. A simulation based analysis is presented, implementing an empirical wear prediction model. Different strategies of maintenance planning are compared by performing a parameter variation study including Monte-Carlo simulations. The maintenance costs are calculated and evaluated with respect to their robustness. Finally, an improved and robust maintenance strategy has been determined. Keywords: Mechanized tunneling, Maintenance, Wear of cutting tools, Process simulation, Robustness, Uncertainty modeling

  12. Stochastic simulation and robust design optimization of integrated photonic filters

    Directory of Open Access Journals (Sweden)

    Weng Tsui-Wei

    2016-07-01

    Full Text Available Manufacturing variations are becoming an unavoidable issue in modern fabrication processes; therefore, it is crucial to be able to include stochastic uncertainties in the design phase. In this paper, integrated photonic coupled ring resonator filters are considered as an example of significant interest. The sparsity structure in photonic circuits is exploited to construct a sparse combined generalized polynomial chaos model, which is then used to analyze related statistics and perform robust design optimization. Simulation results show that the optimized circuits are more robust to fabrication process variations and achieve a reduction of 11%–35% in the mean square errors of the 3 dB bandwidth compared to unoptimized nominal designs.

  13. Exploring Robust and Resilient Pathways to Water Security (Invited)

    Science.gov (United States)

    Brown, C. M.

    2013-12-01

    Lack of water security and the resultant cumulative effects of water-related hazards are understood to hinder economic growth throughout the world. Traditional methods for achieving water security as exemplified in the industrialized world have exerted negative externalities such as degradation of aquatic ecosystems. There is also growing concern that such methods may not be robust to climate variability change. It has been proposed that alternative pathways to water security must be followed in the developing world. However, it is not clear such pathways currently exist and there is an inherent moral hazard in such recommendations. This presentation will present a multidimensional definition of water security, explore the conflict in norms between engineering and ecologically oriented communities, and present a framework synthesizing those norms for assessing and innovating robust and resilient pathways to water security.

  14. Physical Demands of Top-Class Soccer Friendly Matches in Relation to a Playing Position Using Global Positioning System Technology.

    Science.gov (United States)

    Mallo, Javier; Mena, Esteban; Nevado, Fabio; Paredes, Víctor

    2015-09-29

    The aim of this study was to examine the physical demands imposed on professional soccer players during 11-a-side friendly matches in relation to their playing position, using global positioning system (GPS) technology. One hundred and eleven match performances of a Spanish "La Liga" team during the 2010-11 and 2011-12 pre-seasons were selected for analysis. The activities of the players were monitored using GPS technology with a sampling frequency of 1 Hz. Total distance covered, distance in different speed categories, accelerations, and heart rate responses were analyzed in relation to five different playing positions: central defenders (n=23), full-backs (n=20), central midfielders (n=22), wide midfielders (n=26), and forwards (n=20). Distance covered during a match averaged 10.8 km, with wide and central midfielders covering the greatest total distance. Specifically, wide midfielders covered the greatest distances by very high-intensity running (>19.8 km·h-1) and central midfielders by jogging and running (7.2-19.7 km·h-1). On the other hand, central defenders covered the least total distance and at high intensity, although carried out more (pwork rate profile of the players obtained with the GPS was very similar to that obtained with semi-automatic image technologies. However, when comparing results from this study with data available in the literature, important differences were detected in the amount of distance covered by sprinting, which suggests that caution should be taken when comparing data obtained with the GPS with other motion analysis systems, especially regarding high-intensity activities.

  15. Positioning of NORs and NOR-bearing chromosomes in relation to nucleoli.

    Science.gov (United States)

    Kalmárová, Markéta; Smirnov, Evgeny; Masata, Martin; Koberna, Karel; Ligasová, Anna; Popov, Alexey; Raska, Ivan

    2007-10-01

    It is widely accepted that chromosomes occupy more or less fixed positions in mammalian interphase nucleus. However, relation between large-scale order of chromosome positioning and gene activity remains unclear. We used the model of the human ribosomal genes to address specific aspects of this problem. Ribosomal genes are organized at particular chromosomal sites in clusters termed nucleolus organizer regions (NORs). Only some NORs, called competent are generally accepted to be transcriptionally active during interphase. Importantly in this respect, the regularities in distribution of competent, and non-competent NORs among the specific chromosomes were already established in two human-derived cell lines: transformed HeLa and primary LEP cells. In the present study, using FISH and immunocytochemistry, we found that in HeLa and LEP cells the large-scale positioning of the NOR-bearing chromosomes with regard to nucleoli is linked to the transcription activity of rDNA. Namely, the tendency of rDNA-bearing chromosomes to associate with nucleoli correlates with the number of transcriptionally competent NORs in the respective chromosome homologs. Regarding the position of NORs, we found that not only competent but also most of the non-competent NORs are included in the nucleoli. Some intranucleolar NORs (supposedly non-competent) are situated on elongated chromatin protrusions connecting nucleoli with respective chromosome territories spatially distanced from nucleoli.

  16. Sufficient conditions for robust BIBO stabilization : given by the gap metric

    NARCIS (Netherlands)

    Zhu, S.Q.; Hautus, M.L.J.; Praagman, C.

    1988-01-01

    A relation between coprime fractions and the gap metric is presented. Using this result we provide some sufficient conditions for robust BIBO stabilization for a wide class of systems. These conditions allow the plant and the compensator to be disturbed simultaneously.

  17. Robust geographically weighted regression of modeling the Air Polluter Standard Index (APSI)

    Science.gov (United States)

    Warsito, Budi; Yasin, Hasbi; Ispriyanti, Dwi; Hoyyi, Abdul

    2018-05-01

    The Geographically Weighted Regression (GWR) model has been widely applied to many practical fields for exploring spatial heterogenity of a regression model. However, this method is inherently not robust to outliers. Outliers commonly exist in data sets and may lead to a distorted estimate of the underlying regression model. One of solution to handle the outliers in the regression model is to use the robust models. So this model was called Robust Geographically Weighted Regression (RGWR). This research aims to aid the government in the policy making process related to air pollution mitigation by developing a standard index model for air polluter (Air Polluter Standard Index - APSI) based on the RGWR approach. In this research, we also consider seven variables that are directly related to the air pollution level, which are the traffic velocity, the population density, the business center aspect, the air humidity, the wind velocity, the air temperature, and the area size of the urban forest. The best model is determined by the smallest AIC value. There are significance differences between Regression and RGWR in this case, but Basic GWR using the Gaussian kernel is the best model to modeling APSI because it has smallest AIC.

  18. Imagined futures in living with multiple conditions: Positivity, relationality and hopelessness.

    Science.gov (United States)

    Coyle, Lindsay-Ann; Atkinson, Sarah

    2018-02-01

    Hope serves as an overarching concept for a range of engagements that demonstrate the benefits of a positive outlook for coping with chronic conditions of ill-health and disability. A dominant engagement through medicine has positioned hope as a desirable attribute and its opposite, hopelessness, as pathological. In this engagement hope is individual, internally located and largely cognitive and able to be learned. Attaining hope reflects a process of coming to terms with the losses associated with long-term conditions and of imagining new meanings and purposes for the future ahead. This process is characterised by a set of linear temporal stages, from loss and denial to acceptance and reappraising the life-course, by an emphasis on the morally desirable exercise of self-care and by a desired outcome that, in the absence of cure, is hope. Through interviews, we aim to unsettle the privileged status given to a positive outlook through examining the expressions, contexts and negotiations of hopelessness of people living with multiple conditions of ill-health and/or disability. These narratives of hopelessness disclose the ways in which realistic imagined possibilities for the future are constrained by external structures of time and function that demand complex negotiations with places, bodies and other people. As a situated and relational narrative, hopelessness draws our attention to the need to rebalance the exclusive attention to individual, internal resources with a renewed attention to contexts and settings. Moreover, hopelessness can be generative for those living with multiple conditions in shaping alternatively framed priorities with respect to their temporal and interpersonal relations. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Cambodia–China Relations: A Positive-Sum Game?

    Directory of Open Access Journals (Sweden)

    Pheakdey Heng

    2012-01-01

    Full Text Available China has re-emerged to become a dominant foreign player in Cambodia. Politically, Cambodia is one of China’s oldest and closest allies. Economically, China is Cambodia’s top foreign investor, a major donor, and an increasingly important trading partner. Culturally, Chinese values are deeply embedded in many aspects of Cambodian society. However, China’s dominance is surrounded by renewed controversies. While the government warmly welcomes Chinese aid, saying that it comes with no strings attached, many experts are concerned that China is providing aid for more nefarious reasons. Critics also accuse Chinese investment and aid of having exacerbated corruption, weakened governance and harmed human rights, and of ruining Cambodia’s natural resources and environment. With such controversies, it is relevant and significant to assess the roles that China has played and continues to play in Cambodia’s socio-economic development. Using expert interviews, media analysis and an extensive literature review, this paper uniquely contributes to the existing discussion on China–Cambodia relations by closely examining the controversies of China’s investment and aid, critically analysing China’s interests in Cambodia, and asking if the relationship between the two nations is a positive-sum game.

  20. Robust control for a biaxial servo with time delay system based on adaptive tuning technique.

    Science.gov (United States)

    Chen, Tien-Chi; Yu, Chih-Hsien

    2009-07-01

    A robust control method for synchronizing a biaxial servo system motion is proposed in this paper. A new network based cross-coupled control and adaptive tuning techniques are used together to cancel out the skew error. The conventional fixed gain PID cross-coupled controller (CCC) is replaced with the adaptive cross-coupled controller (ACCC) in the proposed control scheme to maintain biaxial servo system synchronization motion. Adaptive-tuning PID (APID) position and velocity controllers provide the necessary control actions to maintain synchronization while following a variable command trajectory. A delay-time compensator (DTC) with an adaptive controller was augmented to set the time delay element, effectively moving it outside the closed loop, enhancing the stability of the robust controlled system. This scheme provides strong robustness with respect to uncertain dynamics and disturbances. The simulation and experimental results reveal that the proposed control structure adapts to a wide range of operating conditions and provides promising results under parameter variations and load changes.

  1. Robust Control for High-Speed Visual Servoing Applications

    DEFF Research Database (Denmark)

    Ellekilde, Lars-Peter; Favrholdt, Peter; Paulin, Mads

    2007-01-01

    This paper presents a new control scheme for visual servoing applications. The approach employs quadratic optimization, and explicitly handles both joint position, velocity and acceleration limits. Contrary to existing techniques, our method does not rely on large safety margins and slow task...... execution to avoid joint limits, and is hence able to exploit the full potential of the robot. Furthermore, our control scheme guarantees a well-defined behavior of the robot even when it is in a singular configuration, and thus handles both internal and external singularities robustly. We demonstrate...... the correctness and efficiency of our approach in a number of visual servoing applications, and compare it to a range of previously proposed techniques....

  2. DESIGN OF ROBUST NAVIGATION AND STABILIZATION LOOPS OF PRECISION ATTITUDE AND HEADING REFERENCE SYSTEM

    Directory of Open Access Journals (Sweden)

    Olha Sushchenko

    2017-11-01

    Full Text Available Purpose: The paper focuses on problems of design of robust precision attitude and heading reference systems, which can be applied in navigation of marine vehicles. The main goal is to create the optimization procedures for design of navigation and stabilization loops of the multimode gimballed system. The optimization procedure of the navigation loop design is based on the parametric robust H2/H∞-optimization. The optimization procedure of the stabilization loop design is based on the robust structural H∞-synthesis. Methods: To solve the given problem the methods of the robust control system theory and optimization methods are used. Results: The kinematical scheme of the precision gimballed attitude and heading reference system is represented. The parametrical optimization algorithm taking into consideration features of the researched system is given. Method of the mixed sensitivity relative to the researched system design is analyzed. Coefficients of the control laws of navigation loops are obtained based on optimization procedure providing compromise between accuracy and robustness. The robust controller of the stabilization loop was developed based on robust structural synthesis using method of the mixed sensitivity. Simulation of navigation and stabilization processes is carried out. Conclusions: The represented results prove efficiency of the proposed procedures, which can be useful for design of precision navigation systems of the moving vehicles.

  3. Intrinsic decoherence theory applied to single C{sub 60} solid state transistors: Robustness in the transmission regimen

    Energy Technology Data Exchange (ETDEWEB)

    Flores, J.C., E-mail: cflores@uta.cl

    2016-03-06

    In relation to a given Hamiltonian and intrinsic decoherence, there are subspaces for which coherence remains robust. Robustness can be classified by the parameter ratios (integer, rational or irrational numbers) defining each subspace. Of particular novelty in this work is application to the single-C{sub 60} transistor where coherence becomes robust in the tunnel transmission regime. In this case, the intrinsic-decoherence parameter defining the theory is explicitly evaluated in good agreement with experimental data. Many of these results are expected to hold for standard quantum dots and mesoscopic devices. - Highlights: • Intrinsic decoherence and transport (mesoscopic). • Robustness condition face to decoherence. • Application to the single C{sub 60} solid state transistor. • Parameter determination based on experiments. • Other cases of robustness.

  4. The importance of robust design methodology

    DEFF Research Database (Denmark)

    Eifler, Tobias; Howard, Thomas J.

    2018-01-01

    infamous recalls in automotive history, that of the GM ignition switch, from the perspective of Robust Design. It is investigated if available Robust Design methods such as sensitivity analysis, tolerance stack-ups, design clarity, etc. would have been suitable to account for the performance variation...

  5. Security and robustness for collaborative monitors

    NARCIS (Netherlands)

    Testerink, Bas; Bulling, Nils; Dastani, Mehdi

    2016-01-01

    Decentralized monitors can be subject to robustness and security risks. Robustness risks include attacks on the monitor’s infrastructure in order to disable parts of its functionality. Security risks include attacks that try to extract information from the monitor and thereby possibly leak sensitive

  6. Robust GPS autonomous signal quality monitoring

    Science.gov (United States)

    Ndili, Awele Nnaemeka

    The Global Positioning System (GPS), introduced by the U.S. Department of Defense in 1973, provides unprecedented world-wide navigation capabilities through a constellation of 24 satellites in global orbit, each emitting a low-power radio-frequency signal for ranging. GPS receivers track these transmitted signals, computing position to within 30 meters from range measurements made to four satellites. GPS has a wide range of applications, including aircraft, marine and land vehicle navigation. Each application places demands on GPS for various levels of accuracy, integrity, system availability and continuity of service. Radio frequency interference (RFI), which results from natural sources such as TV/FM harmonics, radar or Mobile Satellite Systems (MSS), presents a challenge in the use of GPS, by posing a threat to the accuracy, integrity and availability of the GPS navigation solution. In order to use GPS for integrity-sensitive applications, it is therefore necessary to monitor the quality of the received signal, with the objective of promptly detecting the presence of RFI, and thus provide a timely warning of degradation of system accuracy. This presents a challenge, since the myriad kinds of RFI affect the GPS receiver in different ways. What is required then, is a robust method of detecting GPS accuracy degradation, which is effective regardless of the origin of the threat. This dissertation presents a new method of robust signal quality monitoring for GPS. Algorithms for receiver autonomous interference detection and integrity monitoring are demonstrated. Candidate test statistics are derived from fundamental receiver measurements of in-phase and quadrature correlation outputs, and the gain of the Active Gain Controller (AGC). Performance of selected test statistics are evaluated in the presence of RFI: broadband interference, pulsed and non-pulsed interference, coherent CW at different frequencies; and non-RFI: GPS signal fading due to physical blockage and

  7. Robust statistics and geochemical data analysis

    International Nuclear Information System (INIS)

    Di, Z.

    1987-01-01

    Advantages of robust procedures over ordinary least-squares procedures in geochemical data analysis is demonstrated using NURE data from the Hot Springs Quadrangle, South Dakota, USA. Robust principal components analysis with 5% multivariate trimming successfully guarded the analysis against perturbations by outliers and increased the number of interpretable factors. Regression with SINE estimates significantly increased the goodness-of-fit of the regression and improved the correspondence of delineated anomalies with known uranium prospects. Because of the ubiquitous existence of outliers in geochemical data, robust statistical procedures are suggested as routine procedures to replace ordinary least-squares procedures

  8. Towards distortion-free robust image authentication

    International Nuclear Information System (INIS)

    Coltuc, D

    2007-01-01

    This paper investigates a general framework for distortion-free robust image authentication by multiple marking. First, by robust watermarking a subsampled version of image edges is embedded. Then, by reversible watermarking the information needed to recover the original image is inserted, too. The hiding capacity of the reversible watermarking is the essential requirement for this approach. Thus in case of no attacks not only image is authenticated but also the original is exactly recovered. In case of attacks, reversibility is lost, but image can still be authenticated. Preliminary results providing very good robustness against JPEG compression are presented

  9. On the robustness of Herlihy's hierarchy

    Science.gov (United States)

    Jayanti, Prasad

    1993-01-01

    A wait-free hierarchy maps object types to levels in Z(+) U (infinity) and has the following property: if a type T is at level N, and T' is an arbitrary type, then there is a wait-free implementation of an object of type T', for N processes, using only registers and objects of type T. The infinite hierarchy defined by Herlihy is an example of a wait-free hierarchy. A wait-free hierarchy is robust if it has the following property: if T is at level N, and S is a finite set of types belonging to levels N - 1 or lower, then there is no wait-free implementation of an object of type T, for N processes, using any number and any combination of objects belonging to the types in S. Robustness implies that there are no clever ways of combining weak shared objects to obtain stronger ones. Contrary to what many researchers believe, we prove that Herlihy's hierarchy is not robust. We then define some natural variants of Herlihy's hierarchy, which are also infinite wait-free hierarchies. With the exception of one, which is still open, these are not robust either. We conclude with the open question of whether non-trivial robust wait-free hierarchies exist.

  10. Information theory perspective on network robustness

    International Nuclear Information System (INIS)

    Schieber, Tiago A.; Carpi, Laura; Frery, Alejandro C.; Rosso, Osvaldo A.; Pardalos, Panos M.; Ravetti, Martín G.

    2016-01-01

    A crucial challenge in network theory is the study of the robustness of a network when facing a sequence of failures. In this work, we propose a dynamical definition of network robustness based on Information Theory, that considers measurements of the structural changes caused by failures of the network's components. Failures are defined here as a temporal process defined in a sequence. Robustness is then evaluated by measuring dissimilarities between topologies after each time step of the sequence, providing a dynamical information about the topological damage. We thoroughly analyze the efficiency of the method in capturing small perturbations by considering different probability distributions on networks. In particular, we find that distributions based on distances are more consistent in capturing network structural deviations, as better reflect the consequences of the failures. Theoretical examples and real networks are used to study the performance of this methodology. - Highlights: • A novel methodology to measure the robustness of a network to component failure or targeted attacks is proposed. • The use of the network's distance PDF allows a precise analysis. • The method provides a dynamic robustness profile showing the response of the topology to each failure event. • The measure is capable to detect network's critical elements.

  11. Primal and dual approaches to adjustable robust optimization

    NARCIS (Netherlands)

    de Ruiter, Frans

    2018-01-01

    Robust optimization has become an important paradigm to deal with optimization under uncertainty. Adjustable robust optimization is an extension that deals with multistage problems. This thesis starts with a short but comprehensive introduction to adjustable robust optimization. Then the two

  12. Reliability-Based Robustness Analysis for a Croatian Sports Hall

    DEFF Research Database (Denmark)

    Čizmar, Dean; Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2011-01-01

    This paper presents a probabilistic approach for structural robustness assessment for a timber structure built a few years ago. The robustness analysis is based on a structural reliability based framework for robustness and a simplified mechanical system modelling of a timber truss system....... A complex timber structure with a large number of failure modes is modelled with only a few dominant failure modes. First, a component based robustness analysis is performed based on the reliability indices of the remaining elements after the removal of selected critical elements. The robustness...... is expressed and evaluated by a robustness index. Next, the robustness is assessed using system reliability indices where the probabilistic failure model is modelled by a series system of parallel systems....

  13. Robust T1-weighted structural brain imaging and morphometry at 7T using MP2RAGE.

    Directory of Open Access Journals (Sweden)

    Kieran R O'Brien

    Full Text Available PURPOSE: To suppress the noise, by sacrificing some of the signal homogeneity for numerical stability, in uniform T1 weighted (T1w images obtained with the magnetization prepared 2 rapid gradient echoes sequence (MP2RAGE and to compare the clinical utility of these robust T1w images against the uniform T1w images. MATERIALS AND METHODS: 8 healthy subjects (29.0 ± 4.1 years; 6 Male, who provided written consent, underwent two scan sessions within a 24 hour period on a 7T head-only scanner. The uniform and robust T1w image volumes were calculated inline on the scanner. Two experienced radiologists qualitatively rated the images for: general image quality; 7T specific artefacts; and, local structure definition. Voxel-based and volume-based morphometry packages were used to compare the segmentation quality between the uniform and robust images. Statistical differences were evaluated by using a positive sided Wilcoxon rank test. RESULTS: The robust image suppresses background noise inside and outside the skull. The inhomogeneity introduced was ranked as mild. The robust image was significantly ranked higher than the uniform image for both observers (observer 1/2, p-value = 0.0006/0.0004. In particular, an improved delineation of the pituitary gland, cerebellar lobes was observed in the robust versus uniform T1w image. The reproducibility of the segmentation results between repeat scans improved (p-value = 0.0004 from an average volumetric difference across structures of ≈ 6.6% to ≈ 2.4% for the uniform image and robust T1w image respectively. CONCLUSIONS: The robust T1w image enables MP2RAGE to produce, clinically familiar T1w images, in addition to T1 maps, which can be readily used in uniform morphometry packages.

  14. Robust Short-Lag Spatial Coherence Imaging.

    Science.gov (United States)

    Nair, Arun Asokan; Tran, Trac Duy; Bell, Muyinatu A Lediju

    2018-03-01

    Short-lag spatial coherence (SLSC) imaging displays the spatial coherence between backscattered ultrasound echoes instead of their signal amplitudes and is more robust to noise and clutter artifacts when compared with traditional delay-and-sum (DAS) B-mode imaging. However, SLSC imaging does not consider the content of images formed with different lags, and thus does not exploit the differences in tissue texture at each short-lag value. Our proposed method improves SLSC imaging by weighting the addition of lag values (i.e., M-weighting) and by applying robust principal component analysis (RPCA) to search for a low-dimensional subspace for projecting coherence images created with different lag values. The RPCA-based projections are considered to be denoised versions of the originals that are then weighted and added across lags to yield a final robust SLSC (R-SLSC) image. Our approach was tested on simulation, phantom, and in vivo liver data. Relative to DAS B-mode images, the mean contrast, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) improvements with R-SLSC images are 21.22 dB, 2.54, and 2.36, respectively, when averaged over simulated, phantom, and in vivo data and over all lags considered, which corresponds to mean improvements of 96.4%, 121.2%, and 120.5%, respectively. When compared with SLSC images, the corresponding mean improvements with R-SLSC images were 7.38 dB, 1.52, and 1.30, respectively (i.e., mean improvements of 14.5%, 50.5%, and 43.2%, respectively). Results show great promise for smoothing out the tissue texture of SLSC images and enhancing anechoic or hypoechoic target visibility at higher lag values, which could be useful in clinical tasks such as breast cyst visualization, liver vessel tracking, and obese patient imaging.

  15. Pharmacologic management of bone-related complications and bone metastases in postmenopausal women with hormone receptor-positive breast cancer

    Directory of Open Access Journals (Sweden)

    Yardley DA

    2016-05-01

    Full Text Available Denise A Yardley1,2 1Sarah Cannon Research Institute, Nashville, TN, USA; 2Tennessee Oncology, Nashville, TN, USA Abstract: There is a high risk for bone loss and skeletal-related events, including bone metastases, in postmenopausal women with hormone receptor-positive breast cancer. Both the disease itself and its therapeutic treatments can negatively impact bone, resulting in decreases in bone mineral density and increases in bone loss. These negative effects on the bone can significantly impact morbidity and mortality. Effective management and minimization of bone-related complications in postmenopausal women with hormone receptor-positive breast cancer remain essential. This review discusses the current understanding of molecular and biological mechanisms involved in bone turnover and metastases, increased risk for bone-related complications from breast cancer and breast cancer therapy, and current and emerging treatment strategies for managing bone metastases and bone turnover in postmenopausal women with hormone receptor-positive breast cancer. Keywords: breast cancer, bone metastases, hormone receptor-positive, bone-related complications, interventions, management and management strategies, estrogen receptor-positive

  16. Robustness of the Artificial Neural Networks Used for Clustering in the ATLAS Pixel Detector

    CERN Document Server

    The ATLAS collaboration

    2015-01-01

    A study of the robustness of the ATLAS pixel neural network clustering algorithm is presented. The sensitivity to variations to its input is evaluated. These variations are motivated by potential discrepancies between data and simulation due to uncertainties in the modelling of pixel clusters in simulation, as well as uncertainties from the detector calibration. Within reasonable variation magnitudes, the neural networks prove to be robust to most variations. The neural network used to identify pixel clusters created by multiple charged particles, is most sensitive to variations affecting the total amount of charge collected in the cluster. Modifying the read-out threshold has the biggest effect on the clustering's ability to estimate the position of the particle's intersection with the detector.

  17. Robust H(∞) control for spacecraft rendezvous with a noncooperative target.

    Science.gov (United States)

    Wu, Shu-Nan; Zhou, Wen-Ya; Tan, Shu-Jun; Wu, Guo-Qiang

    2013-01-01

    The robust H(∞) control for spacecraft rendezvous with a noncooperative target is addressed in this paper. The relative motion of chaser and noncooperative target is firstly modeled as the uncertain system, which contains uncertain orbit parameter and mass. Then the H(∞) performance and finite time performance are proposed, and a robust H(∞) controller is developed to drive the chaser to rendezvous with the non-cooperative target in the presence of control input saturation, measurement error, and thrust error. The linear matrix inequality technology is used to derive the sufficient condition of the proposed controller. An illustrative example is finally provided to demonstrate the effectiveness of the controller.

  18. Robustness of Distance-to-Default

    DEFF Research Database (Denmark)

    Jessen, Cathrine; Lando, David

    2013-01-01

    Distance-to-default is a remarkably robust measure for ranking firms according to their risk of default. The ranking seems to work despite the fact that the Merton model from which the measure is derived produces default probabilities that are far too small when applied to real data. We use...... simulations to investigate the robustness of the distance-to-default measure to different model specifications. Overall we find distance-to-default to be robust to a number of deviations from the simple Merton model that involve different asset value dynamics and different default triggering mechanisms....... A notable exception is a model with stochastic volatility of assets. In this case both the ranking of firms and the estimated default probabilities using distance-to-default perform significantly worse. We therefore propose a volatility adjustment of the distance-to-default measure, that significantly...

  19. Robustness of digital artist authentication

    DEFF Research Database (Denmark)

    Jacobsen, Robert; Nielsen, Morten

    In many cases it is possible to determine the authenticity of a painting from digital reproductions of the paintings; this has been demonstrated for a variety of artists and with different approaches. Common to all these methods in digital artist authentication is that the potential of the method...... is in focus, while the robustness has not been considered, i.e. the degree to which the data collection process influences the decision of the method. However, in order for an authentication method to be successful in practice, it needs to be robust to plausible error sources from the data collection....... In this paper we investigate the robustness of the newly proposed authenticity method introduced by the authors based on second generation multiresolution analysis. This is done by modelling a number of realistic factors that can occur in the data collection....

  20. Multiobjective Robust Design of the Double Wishbone Suspension System Based on Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Xianfu Cheng

    2014-01-01

    Full Text Available The performance of the suspension system is one of the most important factors in the vehicle design. For the double wishbone suspension system, the conventional deterministic optimization does not consider any deviations of design parameters, so design sensitivity analysis and robust optimization design are proposed. In this study, the design parameters of the robust optimization are the positions of the key points, and the random factors are the uncertainties in manufacturing. A simplified model of the double wishbone suspension is established by software ADAMS. The sensitivity analysis is utilized to determine main design variables. Then, the simulation experiment is arranged and the Latin hypercube design is adopted to find the initial points. The Kriging model is employed for fitting the mean and variance of the quality characteristics according to the simulation results. Further, a particle swarm optimization method based on simple PSO is applied and the tradeoff between the mean and deviation of performance is made to solve the robust optimization problem of the double wishbone suspension system.

  1. Multiobjective Robust Design of the Double Wishbone Suspension System Based on Particle Swarm Optimization

    Science.gov (United States)

    Lin, Yuqun

    2014-01-01

    The performance of the suspension system is one of the most important factors in the vehicle design. For the double wishbone suspension system, the conventional deterministic optimization does not consider any deviations of design parameters, so design sensitivity analysis and robust optimization design are proposed. In this study, the design parameters of the robust optimization are the positions of the key points, and the random factors are the uncertainties in manufacturing. A simplified model of the double wishbone suspension is established by software ADAMS. The sensitivity analysis is utilized to determine main design variables. Then, the simulation experiment is arranged and the Latin hypercube design is adopted to find the initial points. The Kriging model is employed for fitting the mean and variance of the quality characteristics according to the simulation results. Further, a particle swarm optimization method based on simple PSO is applied and the tradeoff between the mean and deviation of performance is made to solve the robust optimization problem of the double wishbone suspension system. PMID:24683334

  2. Robust QRS peak detection by multimodal information fusion of ECG and blood pressure signals.

    Science.gov (United States)

    Ding, Quan; Bai, Yong; Erol, Yusuf Bugra; Salas-Boni, Rebeca; Zhang, Xiaorong; Hu, Xiao

    2016-11-01

    QRS peak detection is a challenging problem when ECG signal is corrupted. However, additional physiological signals may also provide information about the QRS position. In this study, we focus on a unique benchmark provided by PhysioNet/Computing in Cardiology Challenge 2014 and Physiological Measurement focus issue: robust detection of heart beats in multimodal data, which aimed to explore robust methods for QRS detection in multimodal physiological signals. A dataset of 200 training and 210 testing records are used, where the testing records are hidden for evaluating the performance only. An information fusion framework for robust QRS detection is proposed by leveraging existing ECG and ABP analysis tools and combining heart beats derived from different sources. Results show that our approach achieves an overall accuracy of 90.94% and 88.66% on the training and testing datasets, respectively. Furthermore, we observe expected performance at each step of the proposed approach, as an evidence of the effectiveness of our approach. Discussion on the limitations of our approach is also provided.

  3. Multiobjective robust design of the double wishbone suspension system based on particle swarm optimization.

    Science.gov (United States)

    Cheng, Xianfu; Lin, Yuqun

    2014-01-01

    The performance of the suspension system is one of the most important factors in the vehicle design. For the double wishbone suspension system, the conventional deterministic optimization does not consider any deviations of design parameters, so design sensitivity analysis and robust optimization design are proposed. In this study, the design parameters of the robust optimization are the positions of the key points, and the random factors are the uncertainties in manufacturing. A simplified model of the double wishbone suspension is established by software ADAMS. The sensitivity analysis is utilized to determine main design variables. Then, the simulation experiment is arranged and the Latin hypercube design is adopted to find the initial points. The Kriging model is employed for fitting the mean and variance of the quality characteristics according to the simulation results. Further, a particle swarm optimization method based on simple PSO is applied and the tradeoff between the mean and deviation of performance is made to solve the robust optimization problem of the double wishbone suspension system.

  4. Semi-automated Robust Quantification of Lesions (SRQL Toolbox

    Directory of Open Access Journals (Sweden)

    Kaori L Ito

    2017-05-01

    Full Text Available Quantifying lesions in a reliable manner is fundamental for studying the effects of neuroanatomical changes related to recovery in the post-stroke brain. However, the wide variability in lesion characteristics across individuals makes manual lesion segmentation a challenging and often subjective process. This often makes it difficult to combine stroke lesion data across multiple research sites, due to subjective differences in how lesions may be defined. Thus, we developed the Semi-automated Robust Quantification of Lesions (SRQL; https://github.com/npnl/SRQL; DOI: 10.5281/zenodo.557114 Toolbox that performs several analysis steps: 1 a white matter intensity correction that removes healthy white matter voxels from the lesion mask, thereby making lesions slightly more robust to subjective errors; 2 an automated report of descriptive statistics on lesions for simplified comparison between or across groups, and 3 an option to perform analyses in both native and standard space to facilitate analyses in either space. Here, we describe the methods implemented in the toolbox.

  5. Adaptive Critic Nonlinear Robust Control: A Survey.

    Science.gov (United States)

    Wang, Ding; He, Haibo; Liu, Derong

    2017-10-01

    Adaptive dynamic programming (ADP) and reinforcement learning are quite relevant to each other when performing intelligent optimization. They are both regarded as promising methods involving important components of evaluation and improvement, at the background of information technology, such as artificial intelligence, big data, and deep learning. Although great progresses have been achieved and surveyed when addressing nonlinear optimal control problems, the research on robustness of ADP-based control strategies under uncertain environment has not been fully summarized. Hence, this survey reviews the recent main results of adaptive-critic-based robust control design of continuous-time nonlinear systems. The ADP-based nonlinear optimal regulation is reviewed, followed by robust stabilization of nonlinear systems with matched uncertainties, guaranteed cost control design of unmatched plants, and decentralized stabilization of interconnected systems. Additionally, further comprehensive discussions are presented, including event-based robust control design, improvement of the critic learning rule, nonlinear H ∞ control design, and several notes on future perspectives. By applying the ADP-based optimal and robust control methods to a practical power system and an overhead crane plant, two typical examples are provided to verify the effectiveness of theoretical results. Overall, this survey is beneficial to promote the development of adaptive critic control methods with robustness guarantee and the construction of higher level intelligent systems.

  6. A Robust Controller Structure for Pico-Satellite Applications

    DEFF Research Database (Denmark)

    Kragelund, Martin Nygaard; Green, Martin; Kristensen, Mads

    This paper describes the development of a robust controller structure for use in pico-satellite missions. The structure relies on unknown disturbance estimation and use of robust control theory to implement a system that is robust to both unmodeled disturbances and parameter uncertainties. As one...

  7. Anhedonia reflects impairment in making relative value judgments between positive and neutral stimuli in schizophrenia.

    Science.gov (United States)

    Strauss, Gregory P; Visser, Katherine Frost; Keller, William R; Gold, James M; Buchanan, Robert W

    2018-02-27

    Anhedonia (i.e., diminished capacity to experience pleasure) has traditionally been viewed as a core symptom of schizophrenia (SZ). However, modern laboratory-based studies suggest that this definition may be incorrect, as hedonic capacity may be intact. Alternative conceptualizations have proposed that anhedonia may reflect an impairment in generating mental representations of affective value that are needed to guide decision-making and initiate motivated behavior. The current study evaluated this hypothesis in 42 outpatients with SZ and 19 healthy controls (CN) who completed two tasks: (a) an emotional experience task that required them to indicate how positive, negative, and calm/excited they felt in response to a single emotional or neutral photograph; (b) a relative value judgment task where they selected which of 2 photographs they preferred. Results indicated that SZ and CN reported similar levels of positive emotion and arousal in response to emotional and neutral stimuli; however, SZ reported higher negative affect for neutral and pleasant stimuli than CN. In the relative value judgment task, CN displayed clear preference for stimuli differing in valence; however, SZ showed less distinct preferences for positive over neutral stimuli. Findings suggest that although in-the-moment experiences of positive emotion to singular stimuli may be intact in SZ, the ability to make relative value judgments that are needed to guide decision-making is impaired. Original conceptualizations of anhedonia as a diminished capacity for pleasure in SZ may be inaccurate; anhedonia may more accurately reflect a deficit in relative value judgment that results from impaired value representation. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. What makes dreams positive or negative: relations to fundamental dimensions of positive and negative mood.

    Science.gov (United States)

    Kallmeyer, R J; Chang, E C

    1998-02-01

    The present study examined the general emotional content of dreams reported by individuals who typically experience "positive" versus "negative" dreams. Self-reports of the 153 participants indicated that positive versus negative dreamers (ns = 42 and 24, respectively) generally experienced more positive emotions, e.g., joviality, self-assurance, and fewer negative emotions, e.g., fear, sadness. No differences were found in the self-reports of the participants in the experience of surprise, guilt, fatigue, and shyness between the groups, hence, positive and negative dreams do not appear to reflect simply more positive and fewer negative emotions, respectively.

  9. Robust Takagi-Sugeno Fuzzy Dynamic Regulator for Trajectory Tracking of a Pendulum-Cart System

    Directory of Open Access Journals (Sweden)

    Miguel A. Llama

    2015-01-01

    Full Text Available Starting from a nonlinear model for a pendulum-cart system, on which viscous friction is considered, a Takagi-Sugeno (T-S fuzzy augmented model (TSFAM as well as a TSFAM with uncertainty (TSFAMwU is proposed. Since the design of a T-S fuzzy controller is based on the T-S fuzzy model of the nonlinear system, then, to address the trajectory tracking problem of the pendulum-cart system, three T-S fuzzy controllers are proposed via parallel distributed compensation: (1 a T-S fuzzy servo controller (TSFSC designed from the TSFAM; (2 a robust TSFSC (RTSFSC designed from the TSFAMwU; and (3 a robust T-S fuzzy dynamic regulator (RTSFDR designed from the RTSFSC with the addition of a T-S fuzzy observer, which estimates cart and pendulum velocities. Both TSFAM and TSFAMwU are comprised of two fuzzy rules and designed via local approximation in fuzzy partition spaces technique. Feedback gains for the three fuzzy controllers are obtained via linear matrix inequalities approach. A swing-up controller is developed to swing the pendulum up from its pendant position to its upright position. Real-time experiments validate the effectiveness of the proposed schemes, keeping the pendulum in its upright position while the cart follows a reference signal, standing out the RTSFDR.

  10. Bcl-2 over-expression fails to prevent age-related loss of calretinin positive neurons in the mouse dentate gyrus

    Directory of Open Access Journals (Sweden)

    Han Mingbo

    2006-08-01

    Full Text Available Abstract Background Cognitive performance declines with increasing age. Possible cellular mechanisms underlying this age-related functional decline remain incompletely understood. Early studies attributed this functional decline to age-related neuronal loss. Subsequent studies using unbiased stereological techniques found little or no neuronal loss during aging. However, studies using specific cellular markers found age-related loss of specific neuronal types. To test whether there is age-related loss of specific neuronal populations in the hippocampus, and subsequently, whether over-expression of the B-cell lymphoma protein-2 (Bcl-2 in these neurons could delay possible age-related neuronal loss, we examined calretinin (CR positive neurons in the mouse dentate gyrus during aging. Result In normal mice, there was an age-related loss of CR positive cells in the dentate gyrus. At the same region, there was no significant decrease of total numbers of neurons, which suggested that age-related loss of CR positive cells was due to the decrease of CR expression in these cells instead of cell death. In the transgenic mouse line over-expressing Bcl-2 in neurons, there was an age-related loss of CR positive cells. Interestingly, there was also an age-related neuronal loss in this transgenic mouse line. Conclusion These data suggest an age-related loss of CR positive neurons but not total neuronal loss in normal mice and this age-related neuronal change is not prevented by Bcl-2 over-expression.

  11. DC Algorithm for Extended Robust Support Vector Machine.

    Science.gov (United States)

    Fujiwara, Shuhei; Takeda, Akiko; Kanamori, Takafumi

    2017-05-01

    Nonconvex variants of support vector machines (SVMs) have been developed for various purposes. For example, robust SVMs attain robustness to outliers by using a nonconvex loss function, while extended [Formula: see text]-SVM (E[Formula: see text]-SVM) extends the range of the hyperparameter by introducing a nonconvex constraint. Here, we consider an extended robust support vector machine (ER-SVM), a robust variant of E[Formula: see text]-SVM. ER-SVM combines two types of nonconvexity from robust SVMs and E[Formula: see text]-SVM. Because of the two nonconvexities, the existing algorithm we proposed needs to be divided into two parts depending on whether the hyperparameter value is in the extended range or not. The algorithm also heuristically solves the nonconvex problem in the extended range. In this letter, we propose a new, efficient algorithm for ER-SVM. The algorithm deals with two types of nonconvexity while never entailing more computations than either E[Formula: see text]-SVM or robust SVM, and it finds a critical point of ER-SVM. Furthermore, we show that ER-SVM includes the existing robust SVMs as special cases. Numerical experiments confirm the effectiveness of integrating the two nonconvexities.

  12. Physical Demands of Top-Class Soccer Friendly Matches in Relation to a Playing Position Using Global Positioning System Technology

    Directory of Open Access Journals (Sweden)

    Mallo Javier

    2015-09-01

    Full Text Available The aim of this study was to examine the physical demands imposed on professional soccer players during 11-a-side friendly matches in relation to their playing position, using global positioning system (GPS technology. One hundred and eleven match performances of a Spanish “La Liga” team during the 2010-11 and 2011-12 pre-seasons were selected for analysis. The activities of the players were monitored using GPS technology with a sampling frequency of 1 Hz. Total distance covered, distance in different speed categories, accelerations, and heart rate responses were analyzed in relation to five different playing positions: central defenders (n=23, full-backs (n=20, central midfielders (n=22, wide midfielders (n=26, and forwards (n=20. Distance covered during a match averaged 10.8 km, with wide and central midfielders covering the greatest total distance. Specifically, wide midfielders covered the greatest distances by very high-intensity running (>19.8 km·h-1 and central midfielders by jogging and running (7.2-19.7 km·h-1. On the other hand, central defenders covered the least total distance and at high intensity, although carried out more (p<0.05-0.01 accelerations than forwards, wide midfielders, and fullbacks. The work rate profile of the players obtained with the GPS was very similar to that obtained with semi-automatic image technologies. However, when comparing results from this study with data available in the literature, important differences were detected in the amount of distance covered by sprinting, which suggests that caution should be taken when comparing data obtained with the GPS with other motion analysis systems, especially regarding high-intensity activities.

  13. Efficient estimation of the robustness region of biological models with oscillatory behavior.

    Directory of Open Access Journals (Sweden)

    Mochamad Apri

    Full Text Available Robustness is an essential feature of biological systems, and any mathematical model that describes such a system should reflect this feature. Especially, persistence of oscillatory behavior is an important issue. A benchmark model for this phenomenon is the Laub-Loomis model, a nonlinear model for cAMP oscillations in Dictyostelium discoideum. This model captures the most important features of biomolecular networks oscillating at constant frequencies. Nevertheless, the robustness of its oscillatory behavior is not yet fully understood. Given a system that exhibits oscillating behavior for some set of parameters, the central question of robustness is how far the parameters may be changed, such that the qualitative behavior does not change. The determination of such a "robustness region" in parameter space is an intricate task. If the number of parameters is high, it may be also time consuming. In the literature, several methods are proposed that partially tackle this problem. For example, some methods only detect particular bifurcations, or only find a relatively small box-shaped estimate for an irregularly shaped robustness region. Here, we present an approach that is much more general, and is especially designed to be efficient for systems with a large number of parameters. As an illustration, we apply the method first to a well understood low-dimensional system, the Rosenzweig-MacArthur model. This is a predator-prey model featuring satiation of the predator. It has only two parameters and its bifurcation diagram is available in the literature. We find a good agreement with the existing knowledge about this model. When we apply the new method to the high dimensional Laub-Loomis model, we obtain a much larger robustness region than reported earlier in the literature. This clearly demonstrates the power of our method. From the results, we conclude that the biological system underlying is much more robust than was realized until now.

  14. Robust dynamical effects in traffic and chaotic maps on trees

    Indian Academy of Sciences (India)

    Here we study two types of well-defined diffusive dynamics on scale-free trees: traffic of packets as navigated random walks, and chaotic standard maps coupled along the network links. We show that in both cases robust collective dynamic effects appear, which can be measured statistically and related to non-ergodicity of ...

  15. Robust control for constant thrust rendezvous under thrust failure

    Directory of Open Access Journals (Sweden)

    Qi Yongqiang

    2015-04-01

    Full Text Available A robust constant thrust rendezvous approach under thrust failure is proposed based on the relative motion dynamic model. Firstly, the design problem is cast into a convex optimization problem by introducing a Lyapunov function subject to linear matrix inequalities. Secondly, the robust controllers satisfying the requirements can be designed by solving this optimization problem. Then, a new algorithm of constant thrust fitting is proposed through the impulse compensation and the fuel consumption under the theoretical continuous thrust and the actual constant thrust is calculated and compared by using the method proposed in this paper. Finally, the proposed method having the advantage of saving fuel is proved and the actual constant thrust switch control laws are obtained through the isochronous interpolation method, meanwhile, an illustrative example is provided to show the effectiveness of the proposed control design method.

  16. Robust chaotic control of Lorenz system by backstepping design

    International Nuclear Information System (INIS)

    Peng, C.-C.; Chen, C.-L.

    2008-01-01

    This work presents a robust chaotic control strategy for the Lorenz chaos via backstepping design. Backstepping technique is a systematic tool of control law design to provide Lyapunov stability. The concept of extended system is used such that a continuous sliding mode control (SMC) effort is generated using backstepping scheme. In the proposed control algorithm, an adaptation law is applied to estimate the system parameter and the SMC offers the robustness to model uncertainties and external disturbances so that the asymptotical convergence of tracking error can be achieved. Regarding the SMC, an equivalent control algorithm is chosen based on the selection of Lyapunov stability criterion during backstepping approach. The converging rate of error state is relative to the corresponding dynamics of sliding surface. Numerical simulations demonstrate its advantages to a regulation problem and an orbit tracking problem of the Lorenz chaos

  17. Age-Related Decline of Wrist Position Sense and its Relationship to Specific Physical Training

    Directory of Open Access Journals (Sweden)

    Ann Van de Winckel

    2017-11-01

    Full Text Available Perception of limb and body positions is known as proprioception. Sensory feedback, especially from proprioceptive receptors, is essential for motor control. Aging is associated with a decline in position sense at proximal joints, but there is inconclusive evidence of distal joints being equally affected by aging. In addition, there is initial evidence that physical activity attenuates age-related decline in proprioception. Our objectives were, first, to establish wrist proprioceptive acuity in a large group of seniors and compare their perception to young adults, and second, to determine if specific types of training or regular physical activity are associated with preserved wrist proprioception. We recruited community-dwelling seniors (n = 107, mean age, 70 ± 5 years, range, 65–84 years without cognitive decline (Mini Mental State Examination-brief version ≥13/16 and young adult students (n = 51, mean age, 20 ± 1 years, range, 19–26 years. Participants performed contralateral and ipsilateral wrist position sense matching tasks with a bimanual wrist manipulandum to a 15° flexion reference position. Systematic error or proprioceptive bias was computed as the mean difference between matched and reference position. The respective standard deviation over five trials constituted a measure of random error or proprioceptive precision. Current levels of physical activity and previous sport, musical, or dance training were obtained through a questionnaire. We employed longitudinal mixed effects linear models to calculate the effects of trial number, sex, type of matching task and age on wrist proprioceptive bias and precision. The main results were that relative proprioceptive bias was greater in older when compared to young adults (mean difference: 36% ipsilateral, 88% contralateral, p < 0.01. Proprioceptive precision for contralateral but not for ipsilateral matching was smaller in older than in young adults (mean difference: 38

  18. Exploring the relation between positive emotions and the functional status of older adults living independently: a systematic review.

    Science.gov (United States)

    Cabrita, Miriam; Lamers, Sanne M A; Trompetter, Hester R; Tabak, Monique; Vollenbroek-Hutten, Miriam M R

    2017-11-01

    Literature suggests that positive emotions positively influence physiological parameters but their relation to functioning in the daily life of older adults living independently remains unclear. The present work aims to investigate the relation between positive emotions and functional status in daily life of older people living independently. A systematic literature review was conducted using the PubMed, PsycINFO and Scopus electronic databases. Included works were peer-reviewed empirical studies that analysed the relation between positive emotions and ability to perform activities of daily living with older adults living independently. After removal of duplicates, 10 out of 963 papers met the inclusion criteria. Cross-sectional studies (n = 6) provided limited evidence about a relation between positive emotions and functioning in daily life. However, longitudinal studies (n = 4) provide significant evidence for an interaction between the two factors, suggesting that time influences this interaction. The variety on the design and samples of the studies included in this review does not allow a cohesive conclusion of the results. Nevertheless, limited evidence suggests that higher frequency in the experience of positive emotions might be associated with lower functional limitations. The issue of causality in emotions-functioning remains unclear from the review. Further observational studies are highly recommended, supported by innovative technologies.

  19. Robust Self Tuning Controllers

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad

    1985-01-01

    The present thesis concerns robustness properties of adaptive controllers. It is addressed to methods for robustifying self tuning controllers with respect to abrupt changes in the plant parameters. In the thesis an algorithm for estimating abruptly changing parameters is presented. The estimator...... has several operation modes and a detector for controlling the mode. A special self tuning controller has been developed to regulate plant with changing time delay.......The present thesis concerns robustness properties of adaptive controllers. It is addressed to methods for robustifying self tuning controllers with respect to abrupt changes in the plant parameters. In the thesis an algorithm for estimating abruptly changing parameters is presented. The estimator...

  20. Robustness Metrics : How Are They Calculated, When Should They Be Used and Why Do They Give Different Results?

    NARCIS (Netherlands)

    McPhail, C.; Maier, H. R.; Kwakkel, J.H.; Giuliani, M; Castelletti, A; Westra, S.

    2018-01-01

    Robustness is being used increasingly for decision analysis in relation to deep uncertainty and many metrics have been proposed for its quantification. Recent studies have shown that the application of different robustness metrics can result in different rankings of decision alternatives, but

  1. A robust and efficient approach to detect 3D rectal tubes from CT colonography

    Energy Technology Data Exchange (ETDEWEB)

    Yang Xiaoyun; Slabaugh, Greg [Medicsight PLC, Kensington Centre, 66 Hammersmith Road, London (United Kingdom)

    2011-11-15

    Purpose: The rectal tube (RT) is a common source of false positives (FPs) in computer-aided detection (CAD) systems for CT colonography. A robust and efficient detection of RT can improve CAD performance by eliminating such ''obvious'' FPs and increase radiologists' confidence in CAD. Methods: In this paper, we present a novel and robust bottom-up approach to detect the RT. Probabilistic models, trained using kernel density estimation on simple low-level features, are employed to rank and select the most likely RT tube candidate on each axial slice. Then, a shape model, robustly estimated using random sample consensus (RANSAC), infers the global RT path from the selected local detections. Subimages around the RT path are projected into a subspace formed from training subimages of the RT. A quadratic discriminant analysis (QDA) provides a classification of a subimage as RT or non-RT based on the projection. Finally, a bottom-top clustering method is proposed to merge the classification predictions together to locate the tip position of the RT. Results: Our method is validated using a diverse database, including data from five hospitals. On a testing data with 21 patients (42 volumes), 99.5% of annotated RT paths have been successfully detected. Evaluated with CAD, 98.4% of FPs caused by the RT have been detected and removed without any loss of sensitivity. Conclusions: The proposed method demonstrates a high detection rate of the RT path, and when tested in a CAD system, reduces FPs caused by the RT without the loss of sensitivity.

  2. A robust and efficient approach to detect 3D rectal tubes from CT colonography

    International Nuclear Information System (INIS)

    Yang Xiaoyun; Slabaugh, Greg

    2011-01-01

    Purpose: The rectal tube (RT) is a common source of false positives (FPs) in computer-aided detection (CAD) systems for CT colonography. A robust and efficient detection of RT can improve CAD performance by eliminating such ''obvious'' FPs and increase radiologists' confidence in CAD. Methods: In this paper, we present a novel and robust bottom-up approach to detect the RT. Probabilistic models, trained using kernel density estimation on simple low-level features, are employed to rank and select the most likely RT tube candidate on each axial slice. Then, a shape model, robustly estimated using random sample consensus (RANSAC), infers the global RT path from the selected local detections. Subimages around the RT path are projected into a subspace formed from training subimages of the RT. A quadratic discriminant analysis (QDA) provides a classification of a subimage as RT or non-RT based on the projection. Finally, a bottom-top clustering method is proposed to merge the classification predictions together to locate the tip position of the RT. Results: Our method is validated using a diverse database, including data from five hospitals. On a testing data with 21 patients (42 volumes), 99.5% of annotated RT paths have been successfully detected. Evaluated with CAD, 98.4% of FPs caused by the RT have been detected and removed without any loss of sensitivity. Conclusions: The proposed method demonstrates a high detection rate of the RT path, and when tested in a CAD system, reduces FPs caused by the RT without the loss of sensitivity.

  3. Robustness analysis of chiller sequencing control

    International Nuclear Information System (INIS)

    Liao, Yundan; Sun, Yongjun; Huang, Gongsheng

    2015-01-01

    Highlights: • Uncertainties with chiller sequencing control were systematically quantified. • Robustness of chiller sequencing control was systematically analyzed. • Different sequencing control strategies were sensitive to different uncertainties. • A numerical method was developed for easy selection of chiller sequencing control. - Abstract: Multiple-chiller plant is commonly employed in the heating, ventilating and air-conditioning system to increase operational feasibility and energy-efficiency under part load condition. In a multiple-chiller plant, chiller sequencing control plays a key role in achieving overall energy efficiency while not sacrifices the cooling sufficiency for indoor thermal comfort. Various sequencing control strategies have been developed and implemented in practice. Based on the observation that (i) uncertainty, which cannot be avoided in chiller sequencing control, has a significant impact on the control performance and may cause the control fail to achieve the expected control and/or energy performance; and (ii) in current literature few studies have systematically addressed this issue, this paper therefore presents a study on robustness analysis of chiller sequencing control in order to understand the robustness of various chiller sequencing control strategies under different types of uncertainty. Based on the robustness analysis, a simple and applicable method is developed to select the most robust control strategy for a given chiller plant in the presence of uncertainties, which will be verified using case studies

  4. Advances in robust fractional control

    CERN Document Server

    Padula, Fabrizio

    2015-01-01

    This monograph presents design methodologies for (robust) fractional control systems. It shows the reader how to take advantage of the superior flexibility of fractional control systems compared with integer-order systems in achieving more challenging control requirements. There is a high degree of current interest in fractional systems and fractional control arising from both academia and industry and readers from both milieux are catered to in the text. Different design approaches having in common a trade-off between robustness and performance of the control system are considered explicitly. The text generalizes methodologies, techniques and theoretical results that have been successfully applied in classical (integer) control to the fractional case. The first part of Advances in Robust Fractional Control is the more industrially-oriented. It focuses on the design of fractional controllers for integer processes. In particular, it considers fractional-order proportional-integral-derivative controllers, becau...

  5. Incentive-Compatible Robust Line Planning

    Science.gov (United States)

    Bessas, Apostolos; Kontogiannis, Spyros; Zaroliagis, Christos

    The problem of robust line planning requests for a set of origin-destination paths (lines) along with their frequencies in an underlying railway network infrastructure, which are robust to fluctuations of real-time parameters of the solution. In this work, we investigate a variant of robust line planning stemming from recent regulations in the railway sector that introduce competition and free railway markets, and set up a new application scenario: there is a (potentially large) number of line operators that have their lines fixed and operate as competing entities issuing frequency requests, while the management of the infrastructure itself remains the responsibility of a single entity, the network operator. The line operators are typically unwilling to reveal their true incentives, while the network operator strives to ensure a fair (or socially optimal) usage of the infrastructure, e.g., by maximizing the (unknown to him) aggregate incentives of the line operators.

  6. Forecasting exchange rates: a robust regression approach

    OpenAIRE

    Preminger, Arie; Franck, Raphael

    2005-01-01

    The least squares estimation method as well as other ordinary estimation method for regression models can be severely affected by a small number of outliers, thus providing poor out-of-sample forecasts. This paper suggests a robust regression approach, based on the S-estimation method, to construct forecasting models that are less sensitive to data contamination by outliers. A robust linear autoregressive (RAR) and a robust neural network (RNN) models are estimated to study the predictabil...

  7. Robust Inventory System Optimization Based on Simulation and Multiple Criteria Decision Making

    Directory of Open Access Journals (Sweden)

    Ahmad Mortazavi

    2014-01-01

    Full Text Available Inventory management in retailers is difficult and complex decision making process which is related to the conflict criteria, also existence of cyclic changes and trend in demand is inevitable in many industries. In this paper, simulation modeling is considered as efficient tool for modeling of retailer multiproduct inventory system. For simulation model optimization, a novel multicriteria and robust surrogate model is designed based on multiple attribute decision making (MADM method, design of experiments (DOE, and principal component analysis (PCA. This approach as a main contribution of this paper, provides a framework for robust multiple criteria decision making under uncertainty.

  8. Production and robustness of a Cacao agroecosystem: effects of two contrasting types of management strategies.

    Science.gov (United States)

    Sabatier, Rodolphe; Wiegand, Kerstin; Meyer, Katrin

    2013-01-01

    Ecological intensification, i.e. relying on ecological processes to replace chemical inputs, is often presented as the ideal alternative to conventional farming based on an intensive use of chemicals. It is said to both maintain high yield and provide more robustness to the agroecosystem. However few studies compared the two types of management with respect to their consequences for production and robustness toward perturbation. In this study our aim is to assess productive performance and robustness toward diverse perturbations of a Cacao agroecosystem managed with two contrasting groups of strategies: one group of strategies relying on a high level of pesticides and a second relying on low levels of pesticides. We conducted this study using a dynamical model of a Cacao agroecosystem that includes Cacao production dynamics, and dynamics of three insects: a pest (the Cacao Pod Borer, Conopomorpha cramerella) and two characteristic but unspecified beneficial insects (a pollinator of Cacao and a parasitoid of the Cacao Pod Borer). Our results showed two opposite behaviors of the Cacao agroecosystem depending on its management, i.e. an agroecosystem relying on a high input of pesticides and showing low ecosystem functioning and an agroecosystem with low inputs, relying on a high functioning of the ecosystem. From the production point of view, no type of management clearly outclassed the other and their ranking depended on the type of pesticide used. From the robustness point of view, the two types of managements performed differently when subjected to different types of perturbations. Ecologically intensive systems were more robust to pest outbreaks and perturbations related to pesticide characteristics while chemically intensive systems were more robust to Cacao production and management-related perturbation.

  9. A robust H∞ control-based hierarchical mode transition control system for plug-in hybrid electric vehicle

    Science.gov (United States)

    Yang, Chao; Jiao, Xiaohong; Li, Liang; Zhang, Yuanbo; Chen, Zheng

    2018-01-01

    To realize a fast and smooth operating mode transition process from electric driving mode to engine-on driving mode, this paper presents a novel robust hierarchical mode transition control method for a plug-in hybrid electric bus (PHEB) with pre-transmission parallel hybrid powertrain. Firstly, the mode transition process is divided into five stages to clearly describe the powertrain dynamics. Based on the dynamics models of powertrain and clutch actuating mechanism, a hierarchical control structure including two robust H∞ controllers in both upper layer and lower layer is proposed. In upper layer, the demand clutch torque can be calculated by a robust H∞controller considering the clutch engaging time and the vehicle jerk. While in lower layer a robust tracking controller with L2-gain is designed to perform the accurate position tracking control, especially when the parameters uncertainties and external disturbance occur in the clutch actuating mechanism. Simulation and hardware-in-the-loop (HIL) test are carried out in a traditional driving condition of PHEB. Results show that the proposed hierarchical control approach can obtain the good control performance: mode transition time is greatly reduced with the acceptable jerk. Meanwhile, the designed control system shows the obvious robustness with the uncertain parameters and disturbance. Therefore, the proposed approach may offer a theoretical reference for the actual vehicle controller.

  10. Determination of the Relative Positions of Three Planes: Action Research

    Directory of Open Access Journals (Sweden)

    Tuba Ada

    2016-07-01

    Full Text Available The purpose of this study was to explore how a more effective lesson plan and teaching environment can be achieved so as to improve elementary mathematics teacher candidates’ achievement in analytical examination of planes in space. In order to improve achievement in expressing the relative positions of three planes not only algebraically but also visually the study used an action research approach as planned by the researchers. In Implementation 1, the teacher candidates were given the equations of three planes and they were asked to determine the relative positions of the planes so that their prior knowledge could be identified. In this stage, the candidate teachers tried to determine the relative positions of the planes in one direction by examining the plane equations in pairs. In Implementation 2, the candidate teachers were asked to find the solution set of the linear equation system consisting of three equations with three unknowns and to come up with geometric interpretation of this solution. In this stage, some of the candidate teachers were able to solve the equation, but they couldn’t interpret it geometrically. In Implementation 3, Maple, a computer algebra system, was used so that the candidate teachers could visualize and observe the relative positions of the three planes by using the plane equations. In this stage, the candidate teachers associated the set of solutions of the plane equations with the three-dimensional images obtained with Maple. The results of the implementation showed that the proposed plan improved the mathematics teacher candidates’ visualization of the relative positions of the three planes.Keywords: planes in space, analytic geometry, Maple, action researchÜç Düzlemin Birbirine Göre Konumunun Belirlenmesi: Eylem AraştırmasıÖzBu çalışmanın amacı, ilköğretim Matematik öğretmen adaylarının uzayda düzlemlerin analitik incelenmesi konusundaki başarısını arttırmak için daha etkili

  11. Robust-yet-fragile nature of interdependent networks

    Science.gov (United States)

    Tan, Fei; Xia, Yongxiang; Wei, Zhi

    2015-05-01

    Interdependent networks have been shown to be extremely vulnerable based on the percolation model. Parshani et al. [Europhys. Lett. 92, 68002 (2010), 10.1209/0295-5075/92/68002] further indicated that the more intersimilar networks are, the more robust they are to random failures. When traffic load is considered, how do the coupling patterns impact cascading failures in interdependent networks? This question has been largely unexplored until now. In this paper, we address this question by investigating the robustness of interdependent Erdös-Rényi random graphs and Barabási-Albert scale-free networks under either random failures or intentional attacks. It is found that interdependent Erdös-Rényi random graphs are robust yet fragile under either random failures or intentional attacks. Interdependent Barabási-Albert scale-free networks, however, are only robust yet fragile under random failures but fragile under intentional attacks. We further analyze the interdependent communication network and power grid and achieve similar results. These results advance our understanding of how interdependency shapes network robustness.

  12. Comparing the Robustness of Evolutionary Algorithms on the Basis of Benchmark Functions

    Directory of Open Access Journals (Sweden)

    DENIZ ULKER, E.

    2013-05-01

    Full Text Available In real-world optimization problems, even though the solution quality is of great importance, the robustness of the solution is also an important aspect. This paper investigates how the optimization algorithms are sensitive to the variations of control parameters and to the random initialization of the solution set for fixed control parameters. The comparison is performed of three well-known evolutionary algorithms which are Particle Swarm Optimization (PSO algorithm, Differential Evolution (DE algorithm and the Harmony Search (HS algorithm. Various benchmark functions with different characteristics are used for the evaluation of these algorithms. The experimental results show that the solution quality of the algorithms is not directly related to their robustness. In particular, the algorithm that is highly robust can have a low solution quality, or the algorithm that has a high quality of solution can be quite sensitive to the parameter variations.

  13. A robust classic.

    Science.gov (United States)

    Kutzner, Florian; Vogel, Tobias; Freytag, Peter; Fiedler, Klaus

    2011-01-01

    In the present research, we argue for the robustness of illusory correlations (ICs, Hamilton & Gifford, 1976) regarding two boundary conditions suggested in previous research. First, we argue that ICs are maintained under extended experience. Using simulations, we derive conflicting predictions. Whereas noise-based accounts predict ICs to be maintained (Fielder, 2000; Smith, 1991), a prominent account based on discrepancy-reducing feedback learning predicts ICs to disappear (Van Rooy et al., 2003). An experiment involving 320 observations with majority and minority members supports the claim that ICs are maintained. Second, we show that actively using the stereotype to make predictions that are met with reward and punishment does not eliminate the bias. In addition, participants' operant reactions afford a novel online measure of ICs. In sum, our findings highlight the robustness of ICs that can be explained as a result of unbiased but noisy learning.

  14. Improved GPS-based Satellite Relative Navigation Using Femtosecond Laser Relative Distance Measurements

    Directory of Open Access Journals (Sweden)

    Hyungjik Oh

    2016-03-01

    Full Text Available This study developed an approach for improving Carrier-phase Differential Global Positioning System (CDGPS based realtime satellite relative navigation by applying laser baseline measurement data. The robustness against the space operational environment was considered, and a Synthetic Wavelength Interferometer (SWI algorithm based on a femtosecond laser measurement model was developed. The phase differences between two laser wavelengths were combined to measure precise distance. Generated laser data were used to improve estimation accuracy for the float ambiguity of CDGPS data. Relative navigation simulations in real-time were performed using the extended Kalman filter algorithm. The GPS and laser-combined relative navigation accuracy was compared with GPS-only relative navigation solutions to determine the impact of laser data on relative navigation. In numerical simulations, the success rate of integer ambiguity resolution increased when laser data was added to GPS data. The relative navigational errors also improved five-fold and two-fold, relative to the GPS-only error, for 250 m and 5 km initial relative distances, respectively. The methodology developed in this study is suitable for application to future satellite formation-flying missions.

  15. Impact of relative position vehicle-wind blower in a roller test bench under climatic chamber

    International Nuclear Information System (INIS)

    Fernández-Yáñez, P.; Armas, O.; Martínez-Martínez, S.

    2016-01-01

    Highlights: • Air simulation model was developed for a vehicle test bench under climatic chamber. • Good accuracy between experimental data and simulated values were obtained. • Wind blower-vehicle relative position alters external cooling of after-treatment devices. • Vehicle emission certification can be affected by wind blower-vehicle relative position. - Abstract: In terms of energy efficiency and exhaust emissions control, an appropriate design of cooling systems of climatic chambers destined to vehicle certification and/or perform scientific research is becoming increasingly important. European vehicle emissions certification (New European Driving Cycle, NEDC) establishes the position of the wind-simulation blower at 200 mm above floor level. This height is fixed and kept constant independently of the vehicle tested. The position of the blower with respect to the vehicle can modify the external forced convection under the car, where after-treatment devices are located. Consequently, the performance of such devices could be modified and emission results during the certification cycle could be non-representative of real-world driving conditions. The aim of this work is to study the influence of different wind blower-vehicle relative heights on the air velocity and temperature profiles under the car by means of a simple computational fluid dynamics (CFD) approach. A steady state three-dimensional CFD model was developed and applied to the estimation of the air velocity and temperature profiles inside of a climatic chamber equipped with a vehicle roller (chassis dyno) test bench. The simulations reproduce one steady-state condition from NEDC, specifically the EU17 mode (120 km/h, maximum velocity during the cycle). The cool air propelling temperature was 20 °C (minimum temperature in the NEDC range). Simulations were performed employing the Reynolds-Averaged Navier-Stokes (RANS) approach with the realizable k-ε model to provide closure. Air velocity and

  16. Comparing Four Instructional Techniques for Promoting Robust Knowledge

    Science.gov (United States)

    Richey, J. Elizabeth; Nokes-Malach, Timothy J.

    2015-01-01

    Robust knowledge serves as a common instructional target in academic settings. Past research identifying characteristics of experts' knowledge across many domains can help clarify the features of robust knowledge as well as ways of assessing it. We review the expertise literature and identify three key features of robust knowledge (deep,…

  17. Trait and State Positive Emotional Experience in Schizophrenia: A Meta-Analysis

    Science.gov (United States)

    Yan, Chao; Cao, Yuan; Zhang, Yang; Song, Li-Ling; Cheung, Eric F. C.; Chan, Raymond C. K.

    2012-01-01

    Background Prior meta-analyses indicated that people with schizophrenia show impairment in trait hedonic capacity but retain their state hedonic experience (valence) in laboratory-based assessments. Little is known about what is the extent of differences for state positive emotional experience (especially arousal) between people with schizophrenia and healthy controls. It is also not clear whether negative symptoms and gender effect contribute to the variance of positive affect. Methods and Findings The current meta-analysis examined 21 studies assessing state arousal experience, 40 studies measuring state valence experience, and 47studies assessing trait hedonic capacity in schizophrenia. Patients with schizophrenia demonstrated significant impairment in trait hedonic capacity (Cohen’s d = 0.81). However, patients and controls did not statistically differ in state hedonic (valence) as well as exciting (arousal) experience to positive stimuli (Cohen’s d = −0.24 to 0.06). They also reported experiencing relatively robust state aversion and calmness to positive stimuli compared with controls (Cohen’s d = 0.75, 0.56, respectively). Negative symptoms and gender contributed to the variance of findings in positive affect, especially trait hedonic capacity in schizophrenia. Conclusions Our findings suggest that schizophrenia patients have no deficit in state positive emotional experience but impairment in “noncurrent” hedonic capacity, which may be mediated by negative symptoms and gender effect. PMID:22815785

  18. Robust inference in sample selection models

    KAUST Repository

    Zhelonkin, Mikhail; Genton, Marc G.; Ronchetti, Elvezio

    2015-01-01

    The problem of non-random sample selectivity often occurs in practice in many fields. The classical estimators introduced by Heckman are the backbone of the standard statistical analysis of these models. However, these estimators are very sensitive to small deviations from the distributional assumptions which are often not satisfied in practice. We develop a general framework to study the robustness properties of estimators and tests in sample selection models. We derive the influence function and the change-of-variance function of Heckman's two-stage estimator, and we demonstrate the non-robustness of this estimator and its estimated variance to small deviations from the model assumed. We propose a procedure for robustifying the estimator, prove its asymptotic normality and give its asymptotic variance. Both cases with and without an exclusion restriction are covered. This allows us to construct a simple robust alternative to the sample selection bias test. We illustrate the use of our new methodology in an analysis of ambulatory expenditures and we compare the performance of the classical and robust methods in a Monte Carlo simulation study.

  19. Robust inference in sample selection models

    KAUST Repository

    Zhelonkin, Mikhail

    2015-11-20

    The problem of non-random sample selectivity often occurs in practice in many fields. The classical estimators introduced by Heckman are the backbone of the standard statistical analysis of these models. However, these estimators are very sensitive to small deviations from the distributional assumptions which are often not satisfied in practice. We develop a general framework to study the robustness properties of estimators and tests in sample selection models. We derive the influence function and the change-of-variance function of Heckman\\'s two-stage estimator, and we demonstrate the non-robustness of this estimator and its estimated variance to small deviations from the model assumed. We propose a procedure for robustifying the estimator, prove its asymptotic normality and give its asymptotic variance. Both cases with and without an exclusion restriction are covered. This allows us to construct a simple robust alternative to the sample selection bias test. We illustrate the use of our new methodology in an analysis of ambulatory expenditures and we compare the performance of the classical and robust methods in a Monte Carlo simulation study.

  20. Testing links between childhood positive peer relations and externalizing outcomes through a randomized controlled intervention study.

    Science.gov (United States)

    Witvliet, Miranda; van Lier, Pol A C; Cuijpers, Pim; Koot, Hans M

    2009-10-01

    In this study, the authors used a randomized controlled trial to explore the link between having positive peer relations and externalizing outcomes in 758 children followed from kindergarten to the end of 2nd grade. Children were randomly assigned to the Good Behavior Game (GBG), a universal classroom-based preventive intervention, or a control condition. Children's acceptance by peers, their number of mutual friends, and their proximity to others were assessed annually through peer ratings. Externalizing behavior was annually rated by teachers. Reductions in children's externalizing behavior and improvements in positive peer relations were found among GBG children, as compared with control-group children. Reductions in externalizing behavior appeared to be partly mediated by the improvements in peer acceptance. This mediating role of peer acceptance was found for boys only. The results suggest that positive peer relations are not just markers, but they are environmental mediators of boys' externalizing behavior development. Implications for research and prevention are discussed. (c) 2009 APA, all rights reserved.

  1. REINA at CLEF 2007 Robust Track (2007)

    OpenAIRE

    Zazo, Ángel F.; G.-Figuerola, Carlos; Alonso-Berrocal, José-Luis

    2007-01-01

    This paper describes our work at CLEF 2007 Robust Task. We have participated in the monolingual (English, French and Portuguese) and the bilingual (English to French) subtask. At CLEF 2006 our research group obtained very good results applying local query expansion using windows of terms in the robust task. This year we have used the same expansion technique, but taking into account some criteria of robustness: MAP, GMAP, MMR, GS@10, P@10, number of failed topics, number of topics bellow 0.1 ...

  2. Robust methods for data reduction

    CERN Document Server

    Farcomeni, Alessio

    2015-01-01

    Robust Methods for Data Reduction gives a non-technical overview of robust data reduction techniques, encouraging the use of these important and useful methods in practical applications. The main areas covered include principal components analysis, sparse principal component analysis, canonical correlation analysis, factor analysis, clustering, double clustering, and discriminant analysis.The first part of the book illustrates how dimension reduction techniques synthesize available information by reducing the dimensionality of the data. The second part focuses on cluster and discriminant analy

  3. Sexual orientation and spatial position effects on selective forms of object location memory.

    Science.gov (United States)

    Rahman, Qazi; Newland, Cherie; Smyth, Beatrice Mary

    2011-04-01

    Prior research has demonstrated robust sex and sexual orientation-related differences in object location memory in humans. Here we show that this sexual variation may depend on the spatial position of target objects and the task-specific nature of the spatial array. We tested the recovery of object locations in three object arrays (object exchanges, object shifts, and novel objects) relative to veridical center (left compared to right side of the arrays) in a sample of 35 heterosexual men, 35 heterosexual women, and 35 homosexual men. Relative to heterosexual men, heterosexual women showed better location recovery in the right side of the array during object exchanges and homosexual men performed better in the right side during novel objects. However, the difference between heterosexual and homosexual men disappeared after controlling for IQ. Heterosexual women and homosexual men did not differ significantly from each other in location change detection with respect to task or side of array. These data suggest that visual space biases in processing categorical spatial positions may enhance aspects of object location memory in heterosexual women. Copyright © 2010 Elsevier Inc. All rights reserved.

  4. Robust surgery loading

    NARCIS (Netherlands)

    Hans, Elias W.; Wullink, Gerhard; van Houdenhoven, Mark; Kazemier, Geert

    2008-01-01

    We consider the robust surgery loading problem for a hospital’s operating theatre department, which concerns assigning surgeries and sufficient planned slack to operating room days. The objective is to maximize capacity utilization and minimize the risk of overtime, and thus cancelled patients. This

  5. Robust policy choice under Calvo and Rotemberg pricing

    OpenAIRE

    Sienknecht, Sebastian

    2012-01-01

    This paper examines the robustness of welfare-based policy choices across the nonlinear Calvo and Rotemberg pricing assumptions. Comparisons between simple interest rate rules turn out to be robust and independent of the price dispersion inherent in the Calvo setting. This robustness is violated if there is a policy alternative that controls for price dispersion.

  6. Relative position of the mandibular foramen in different age groups of children: A radiographic study

    Directory of Open Access Journals (Sweden)

    Poonacha K

    2010-09-01

    Full Text Available Objectives: To assess the relative position of the mandibular foramen (MF and to evaluate the measurement of gonial angle (GoA and its relationship with distances between different mandibular borders in growing children between 3 and 13years of dental age. Materials and methods: The radiographs were traced to arrive at six linear and two angular measurements from which the relative position of the MF was assessed and compared in different age groups to determine the growth pattern of the mandible and changes in the location of the MF. Results: The distances between the MF and the anterior plane of the ramus were greater than that between MF and posterior plane of the ramus through all stages. There was a maximum increase in the vertical dimensions of the mandible compared with the horizontal dimensions, particularly in the late mixed dentition period. Conclusion: The mandible and its growth did not alter the position of the MF, both vertically and horizontally, in relation to different landmarks, and more obtuse GoA indicated an increased growth potential of the mandible. This has major implications in the inferior alveolar nerve block technique when used in children.

  7. High-precision relative position and attitude measurement for on-orbit maintenance of spacecraft

    Science.gov (United States)

    Zhu, Bing; Chen, Feng; Li, Dongdong; Wang, Ying

    2018-02-01

    In order to realize long-term on-orbit running of satellites, space stations, etc spacecrafts, in addition to the long life design of devices, The life of the spacecraft can also be extended by the on-orbit servicing and maintenance. Therefore, it is necessary to keep precise and detailed maintenance of key components. In this paper, a high-precision relative position and attitude measurement method used in the maintenance of key components is given. This method mainly considers the design of the passive cooperative marker, light-emitting device and high resolution camera in the presence of spatial stray light and noise. By using a series of algorithms, such as background elimination, feature extraction, position and attitude calculation, and so on, the high precision relative pose parameters as the input to the control system between key operation parts and maintenance equipment are obtained. The simulation results show that the algorithm is accurate and effective, satisfying the requirements of the precision operation technique.

  8. Traffic-related air pollution and obesity formation in children: a longitudinal, multilevel analysis.

    Science.gov (United States)

    Jerrett, Michael; McConnell, Rob; Wolch, Jennifer; Chang, Roger; Lam, Claudia; Dunton, Genevieve; Gilliland, Frank; Lurmann, Fred; Islam, Talat; Berhane, Kiros

    2014-06-09

    Biologically plausible mechanisms link traffic-related air pollution to metabolic disorders and potentially to obesity. Here we sought to determine whether traffic density and traffic-related air pollution were positively associated with growth in body mass index (BMI = kg/m2) in children aged 5-11 years. Participants were drawn from a prospective cohort of children who lived in 13 communities across Southern California (N = 4550). Children were enrolled while attending kindergarten and first grade and followed for 4 years, with height and weight measured annually. Dispersion models were used to estimate exposure to traffic-related air pollution. Multilevel models were used to estimate and test traffic density and traffic pollution related to BMI growth. Data were collected between 2002-2010 and analyzed in 2011-12. Traffic pollution was positively associated with growth in BMI and was robust to adjustment for many confounders. The effect size in the adjusted model indicated about a 13.6% increase in annual BMI growth when comparing the lowest to the highest tenth percentile of air pollution exposure, which resulted in an increase of nearly 0.4 BMI units on attained BMI at age 10. Traffic density also had a positive association with BMI growth, but this effect was less robust in multivariate models. Traffic pollution was positively associated with growth in BMI in children aged 5-11 years. Traffic pollution may be controlled via emission restrictions; changes in land use that promote jobs-housing balance and use of public transit and hence reduce vehicle miles traveled; promotion of zero emissions vehicles; transit and car-sharing programs; or by limiting high pollution traffic, such as diesel trucks, from residential areas or places where children play outdoors, such as schools and parks. These measures may have beneficial effects in terms of reduced obesity formation in children.

  9. Female song rates in response to simulated intruder are positively related to reproductive success.

    Directory of Open Access Journals (Sweden)

    Kristal E Cain

    2015-10-01

    Full Text Available Bird song is well studied in males as a sexually selected behavior. However, although song is also common among females, it is infrequently examined and poorly understood. Research suggests that song is often used as a resource defense behavior and is important in female-female competition for limited resources, e.g. mates and territories. If so, song should be positively related to fitness and related to other resource defense behaviors, but this possibility has rarely been explored. Here we examine fitness estimates in relation to spontaneous song rates and song rates in response to a simulated intruder (playback, in the superb fairy-wren (Malurus cyaneus, a cooperatively breeding songbird. We also determine how song rates relate to other territorial defense behaviors. Song rate in response to playback, but not spontaneous song rate, was positively related to nest success and the number of fledglings produced by successful females. Further, response song rate was also correlated with other territorial defense behaviors (latency to respond and flights. This evidence supports the hypothesis that female song may be used in the context of female-female competition to improve access to limited reproductive resources, and suggests that song may provide direct fitness benefits.

  10. Risk, Robustness and Water Resources Planning Under Uncertainty

    Science.gov (United States)

    Borgomeo, Edoardo; Mortazavi-Naeini, Mohammad; Hall, Jim W.; Guillod, Benoit P.

    2018-03-01

    Risk-based water resources planning is based on the premise that water managers should invest up to the point where the marginal benefit of risk reduction equals the marginal cost of achieving that benefit. However, this cost-benefit approach may not guarantee robustness under uncertain future conditions, for instance under climatic changes. In this paper, we expand risk-based decision analysis to explore possible ways of enhancing robustness in engineered water resources systems under different risk attitudes. Risk is measured as the expected annual cost of water use restrictions, while robustness is interpreted in the decision-theoretic sense as the ability of a water resource system to maintain performance—expressed as a tolerable risk of water use restrictions—under a wide range of possible future conditions. Linking risk attitudes with robustness allows stakeholders to explicitly trade-off incremental increases in robustness with investment costs for a given level of risk. We illustrate the framework through a case study of London's water supply system using state-of-the -art regional climate simulations to inform the estimation of risk and robustness.

  11. Self-reported oral and general health in relation to socioeconomic position

    OpenAIRE

    Hakeberg, Magnus; Wide Boman, Ulla

    2017-01-01

    Abstract Background During the past two decades, several scientific publications from different countries have shown how oral health in the population varies with social determinants. The aim of the present study was to explore the relationship between self-reported oral and general health in relation to different measures of socioeconomic position. Methods Data were collected from a randomly selected sample of the adult population in Sweden (n = 3500, mean age 53.4 years, 53.1% women). The r...

  12. Robust H ∞ Control for Spacecraft Rendezvous with a Noncooperative Target

    Science.gov (United States)

    Wu, Shu-Nan; Zhou, Wen-Ya; Tan, Shu-Jun; Wu, Guo-Qiang

    2013-01-01

    The robust H ∞ control for spacecraft rendezvous with a noncooperative target is addressed in this paper. The relative motion of chaser and noncooperative target is firstly modeled as the uncertain system, which contains uncertain orbit parameter and mass. Then the H ∞ performance and finite time performance are proposed, and a robust H ∞ controller is developed to drive the chaser to rendezvous with the non-cooperative target in the presence of control input saturation, measurement error, and thrust error. The linear matrix inequality technology is used to derive the sufficient condition of the proposed controller. An illustrative example is finally provided to demonstrate the effectiveness of the controller. PMID:24027446

  13. TAO-robust backpropagation learning algorithm.

    Science.gov (United States)

    Pernía-Espinoza, Alpha V; Ordieres-Meré, Joaquín B; Martínez-de-Pisón, Francisco J; González-Marcos, Ana

    2005-03-01

    In several fields, as industrial modelling, multilayer feedforward neural networks are often used as universal function approximations. These supervised neural networks are commonly trained by a traditional backpropagation learning format, which minimises the mean squared error (mse) of the training data. However, in the presence of corrupted data (outliers) this training scheme may produce wrong models. We combine the benefits of the non-linear regression model tau-estimates [introduced by Tabatabai, M. A. Argyros, I. K. Robust Estimation and testing for general nonlinear regression models. Applied Mathematics and Computation. 58 (1993) 85-101] with the backpropagation algorithm to produce the TAO-robust learning algorithm, in order to deal with the problems of modelling with outliers. The cost function of this approach has a bounded influence function given by the weighted average of two psi functions, one corresponding to a very robust estimate and the other to a highly efficient estimate. The advantages of the proposed algorithm are studied with an example.

  14. Robustness of holonomic quantum gates

    International Nuclear Information System (INIS)

    Solinas, P.; Zanardi, P.; Zanghi, N.

    2005-01-01

    Full text: If the driving field fluctuates during the quantum evolution this produces errors in the applied operator. The holonomic (and geometrical) quantum gates are believed to be robust against some kind of noise. Because of the geometrical dependence of the holonomic operators can be robust against this kind of noise; in fact if the fluctuations are fast enough they cancel out leaving the final operator unchanged. I present the numerical studies of holonomic quantum gates subject to this parametric noise, the fidelity of the noise and ideal evolution is calculated for different noise correlation times. The holonomic quantum gates seem robust not only for fast fluctuating fields but also for slow fluctuating fields. These results can be explained as due to the geometrical feature of the holonomic operator: for fast fluctuating fields the fluctuations are canceled out, for slow fluctuating fields the fluctuations do not perturb the loop in the parameter space. (author)

  15. Robust estimation and hypothesis testing

    CERN Document Server

    Tiku, Moti L

    2004-01-01

    In statistical theory and practice, a certain distribution is usually assumed and then optimal solutions sought. Since deviations from an assumed distribution are very common, one cannot feel comfortable with assuming a particular distribution and believing it to be exactly correct. That brings the robustness issue in focus. In this book, we have given statistical procedures which are robust to plausible deviations from an assumed mode. The method of modified maximum likelihood estimation is used in formulating these procedures. The modified maximum likelihood estimators are explicit functions of sample observations and are easy to compute. They are asymptotically fully efficient and are as efficient as the maximum likelihood estimators for small sample sizes. The maximum likelihood estimators have computational problems and are, therefore, elusive. A broad range of topics are covered in this book. Solutions are given which are easy to implement and are efficient. The solutions are also robust to data anomali...

  16. Tracing evolutionary relicts of positive selection on eight malaria-related immune genes in mammals.

    Science.gov (United States)

    Huang, Bing-Hong; Liao, Pei-Chun

    2015-07-01

    Plasmodium-induced malaria widely infects primates and other mammals. Multiple past studies have revealed that positive selection could be the main evolutionary force triggering the genetic diversity of anti-malaria resistance-associated genes in human or primates. However, researchers focused most of their attention on the infra-generic and intra-specific genome evolution rather than analyzing the complete evolutionary history of mammals. Here we extend previous research by testing the evolutionary link of natural selection on eight candidate genes associated with malaria resistance in mammals. Three of the eight genes were detected to be affected by recombination, including TNF-α, iNOS and DARC. Positive selection was detected in the rest five immunogenes multiple times in different ancestral lineages of extant species throughout the mammalian evolution. Signals of positive selection were exposed in four malaria-related immunogenes in primates: CCL2, IL-10, HO1 and CD36. However, selection signals of G6PD have only been detected in non-primate eutherians. Significantly higher evolutionary rates and more radical amino acid replacement were also detected in primate CD36, suggesting its functional divergence from other eutherians. Prevalent positive selection throughout the evolutionary trajectory of mammalian malaria-related genes supports the arms race evolutionary hypothesis of host genetic response of mammalian immunogenes to infectious pathogens. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  17. Robust automated mass spectra interpretation and chemical formula calculation using mixed integer linear programming.

    Science.gov (United States)

    Baran, Richard; Northen, Trent R

    2013-10-15

    Untargeted metabolite profiling using liquid chromatography and mass spectrometry coupled via electrospray ionization is a powerful tool for the discovery of novel natural products, metabolic capabilities, and biomarkers. However, the elucidation of the identities of uncharacterized metabolites from spectral features remains challenging. A critical step in the metabolite identification workflow is the assignment of redundant spectral features (adducts, fragments, multimers) and calculation of the underlying chemical formula. Inspection of the data by experts using computational tools solving partial problems (e.g., chemical formula calculation for individual ions) can be performed to disambiguate alternative solutions and provide reliable results. However, manual curation is tedious and not readily scalable or standardized. Here we describe an automated procedure for the robust automated mass spectra interpretation and chemical formula calculation using mixed integer linear programming optimization (RAMSI). Chemical rules among related ions are expressed as linear constraints and both the spectra interpretation and chemical formula calculation are performed in a single optimization step. This approach is unbiased in that it does not require predefined sets of neutral losses and positive and negative polarity spectra can be combined in a single optimization. The procedure was evaluated with 30 experimental mass spectra and was found to effectively identify the protonated or deprotonated molecule ([M + H](+) or [M - H](-)) while being robust to the presence of background ions. RAMSI provides a much-needed standardized tool for interpreting ions for subsequent identification in untargeted metabolomics workflows.

  18. Alcohol-related memory associations in positive and negative affect situations: drinking motives, working memory capacity, and prospective drinking.

    Science.gov (United States)

    Salemink, Elske; Wiers, Reinout W

    2014-03-01

    Although studies on explicit alcohol cognitions have identified positive and negative reinforcing drinking motives that are differentially related to drinking indices, such a distinction has received less attention in studies on implicit cognitions. An alcohol-related Word-Sentence Association Task was used to assess implicit alcohol-related memory associations in positive and negative affect situations in 92 participants. Results revealed that enhancement motives were specifically associated with the endorsement of alcohol words in positive affect situations and coping motives were associated with the endorsement of alcohol words in negative affect situations. Furthermore, alcohol associations in positive affect situations predicted prospective alcohol use and number of binges, depending on levels of working memory capacity. The current findings shed more light on the underpinnings of alcohol use and suggest that implicit memory processes and working memory capacity might be important targets for intervention.

  19. Influence of relative trophic position and carbon source on selenium bioaccumulation in turtles from a coal fly-ash spill site

    International Nuclear Information System (INIS)

    Van Dyke, James U.; Hopkins, William A.; Jackson, Brian P.

    2013-01-01

    Selenium (Se) is a bioaccumulative constituent of coal fly-ash that can disrupt reproduction of oviparous wildlife. In food webs, the greatest enrichment of Se occurs at the lowest trophic levels, making it readily bioavailable to higher consumers. However, subsequent enrichment at higher trophic levels is less pronounced, leading to mixed tendencies for Se to biomagnify. We used stable isotopes ( 15 N and 13 C) in claws to infer relative trophic positions and relative carbon sources, respectively, of seven turtle species near the site of a recently-remediated coal fly-ash spill. We then tested whether Se concentrations differed with relative trophic position or relative carbon source. We did not observe a strong relationship between δ 15 N and Se concentration. Instead, selenium concentrations decreased with increasing δ 13 C among species. Therefore, in an assemblage of closely-related aquatic vertebrates, relative carbon source was a better predictor of Se bioaccumulation than was relative trophic position. -- Highlights: •Stable isotope results showed trophic separation among turtle species. •Selenium concentrations did not biomagnify with relative trophic position. •Selenium concentrations decreased with increasing δ 13 C among species. •Carbon source influenced Se bioaccumulation in an assemblage of related vertebrates. -- Stable isotope differences indicate that claw selenium concentrations differ among relative carbon sources, and not among relative trophic positions, in an assemblage of aquatic turtles

  20. Robust Spacecraft Component Detection in Point Clouds

    Directory of Open Access Journals (Sweden)

    Quanmao Wei

    2018-03-01

    Full Text Available Automatic component detection of spacecraft can assist in on-orbit operation and space situational awareness. Spacecraft are generally composed of solar panels and cuboidal or cylindrical modules. These components can be simply represented by geometric primitives like plane, cuboid and cylinder. Based on this prior, we propose a robust automatic detection scheme to automatically detect such basic components of spacecraft in three-dimensional (3D point clouds. In the proposed scheme, cylinders are first detected in the iteration of the energy-based geometric model fitting and cylinder parameter estimation. Then, planes are detected by Hough transform and further described as bounded patches with their minimum bounding rectangles. Finally, the cuboids are detected with pair-wise geometry relations from the detected patches. After successive detection of cylinders, planar patches and cuboids, a mid-level geometry representation of the spacecraft can be delivered. We tested the proposed component detection scheme on spacecraft 3D point clouds synthesized by computer-aided design (CAD models and those recovered by image-based reconstruction, respectively. Experimental results illustrate that the proposed scheme can detect the basic geometric components effectively and has fine robustness against noise and point distribution density.

  1. Robust Spacecraft Component Detection in Point Clouds.

    Science.gov (United States)

    Wei, Quanmao; Jiang, Zhiguo; Zhang, Haopeng

    2018-03-21

    Automatic component detection of spacecraft can assist in on-orbit operation and space situational awareness. Spacecraft are generally composed of solar panels and cuboidal or cylindrical modules. These components can be simply represented by geometric primitives like plane, cuboid and cylinder. Based on this prior, we propose a robust automatic detection scheme to automatically detect such basic components of spacecraft in three-dimensional (3D) point clouds. In the proposed scheme, cylinders are first detected in the iteration of the energy-based geometric model fitting and cylinder parameter estimation. Then, planes are detected by Hough transform and further described as bounded patches with their minimum bounding rectangles. Finally, the cuboids are detected with pair-wise geometry relations from the detected patches. After successive detection of cylinders, planar patches and cuboids, a mid-level geometry representation of the spacecraft can be delivered. We tested the proposed component detection scheme on spacecraft 3D point clouds synthesized by computer-aided design (CAD) models and those recovered by image-based reconstruction, respectively. Experimental results illustrate that the proposed scheme can detect the basic geometric components effectively and has fine robustness against noise and point distribution density.

  2. An Intercompany Perspective on Biopharmaceutical Drug Product Robustness Studies.

    Science.gov (United States)

    Morar-Mitrica, Sorina; Adams, Monica L; Crotts, George; Wurth, Christine; Ihnat, Peter M; Tabish, Tanvir; Antochshuk, Valentyn; DiLuzio, Willow; Dix, Daniel B; Fernandez, Jason E; Gupta, Kapil; Fleming, Michael S; He, Bing; Kranz, James K; Liu, Dingjiang; Narasimhan, Chakravarthy; Routhier, Eric; Taylor, Katherine D; Truong, Nobel; Stokes, Elaine S E

    2018-02-01

    The Biophorum Development Group (BPDG) is an industry-wide consortium enabling networking and sharing of best practices for the development of biopharmaceuticals. To gain a better understanding of current industry approaches for establishing biopharmaceutical drug product (DP) robustness, the BPDG-Formulation Point Share group conducted an intercompany collaboration exercise, which included a bench-marking survey and extensive group discussions around the scope, design, and execution of robustness studies. The results of this industry collaboration revealed several key common themes: (1) overall DP robustness is defined by both the formulation and the manufacturing process robustness; (2) robustness integrates the principles of quality by design (QbD); (3) DP robustness is an important factor in setting critical quality attribute control strategies and commercial specifications; (4) most companies employ robustness studies, along with prior knowledge, risk assessments, and statistics, to develop the DP design space; (5) studies are tailored to commercial development needs and the practices of each company. Three case studies further illustrate how a robustness study design for a biopharmaceutical DP balances experimental complexity, statistical power, scientific understanding, and risk assessment to provide the desired product and process knowledge. The BPDG-Formulation Point Share discusses identified industry challenges with regard to biopharmaceutical DP robustness and presents some recommendations for best practices. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  3. Robust Structured Control Design via LMI Optimization

    DEFF Research Database (Denmark)

    Adegas, Fabiano Daher; Stoustrup, Jakob

    2011-01-01

    This paper presents a new procedure for discrete-time robust structured control design. Parameter-dependent nonconvex conditions for stabilizable and induced L2-norm performance controllers are solved by an iterative linear matrix inequalities (LMI) optimization. A wide class of controller...... structures including decentralized of any order, fixed-order dynamic output feedback, static output feedback can be designed robust to polytopic uncertainties. Stability is proven by a parameter-dependent Lyapunov function. Numerical examples on robust stability margins shows that the proposed procedure can...

  4. Measuring implicit attitudes: A positive framing bias flaw in the Implicit Relational Assessment Procedure (IRAP).

    Science.gov (United States)

    O'Shea, Brian; Watson, Derrick G; Brown, Gordon D A

    2016-02-01

    How can implicit attitudes best be measured? The Implicit Relational Assessment Procedure (IRAP), unlike the Implicit Association Test (IAT), claims to measure absolute, not just relative, implicit attitudes. In the IRAP, participants make congruent (Fat Person-Active: false; Fat Person-Unhealthy: true) or incongruent (Fat Person-Active: true; Fat Person-Unhealthy: false) responses in different blocks of trials. IRAP experiments have reported positive or neutral implicit attitudes (e.g., neutral attitudes toward fat people) in cases in which negative attitudes are normally found on explicit or other implicit measures. It was hypothesized that these results might reflect a positive framing bias (PFB) that occurs when participants complete the IRAP. Implicit attitudes toward categories with varying prior associations (nonwords, social systems, flowers and insects, thin and fat people) were measured. Three conditions (standard, positive framing, and negative framing) were used to measure whether framing influenced estimates of implicit attitudes. It was found that IRAP scores were influenced by how the task was framed to the participants, that the framing effect was modulated by the strength of prior stimulus associations, and that a default PFB led to an overestimation of positive implicit attitudes when measured by the IRAP. Overall, the findings question the validity of the IRAP as a tool for the measurement of absolute implicit attitudes. A new tool (Simple Implicit Procedure:SIP) for measuring absolute, not just relative, implicit attitudes is proposed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  5. Robust control of speed and temperature in a power plant gas turbine.

    Science.gov (United States)

    Najimi, Ebrahim; Ramezani, Mohammad Hossein

    2012-03-01

    In this paper, an H(∞) robust controller has been designed for an identified model of MONTAZER GHAEM power plant gas turbine (GE9001E). In design phase, a linear model (ARX model) which is obtained using real data has been applied. Since the turbine has been used in a combined cycle power plant, its speed and also the exhaust gas temperature should be adjusted simultaneously by controlling fuel signals and compressor inlet guide vane (IGV) position. Considering the limitations on the system inputs, the aim of the control is to maintain the turbine speed and the exhaust gas temperature within desired interval under uncertainties and load demand disturbances. Simulation results of applying the proposed robust controller on the nonlinear model of the system (NARX model), fairly fulfilled the predefined aims. Simulations also show the improvement in the performance compared to MPC and PID controllers for the same conditions. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  6. Robust Estimator for Non-Line-of-Sight Error Mitigation in Indoor Localization

    Directory of Open Access Journals (Sweden)

    Marco A

    2006-01-01

    Full Text Available Indoor localization systems are undoubtedly of interest in many application fields. Like outdoor systems, they suffer from non-line-of-sight (NLOS errors which hinder their robustness and accuracy. Though many ad hoc techniques have been developed to deal with this problem, unfortunately most of them are not applicable indoors due to the high variability of the environment (movement of furniture and of people, etc.. In this paper, we describe the use of robust regression techniques to detect and reject NLOS measures in a location estimation using multilateration. We show how the least-median-of-squares technique can be used to overcome the effects of NLOS errors, even in environments with little infrastructure, and validate its suitability by comparing it to other methods described in the bibliography. We obtained remarkable results when using it in a real indoor positioning system that works with Bluetooth and ultrasound (BLUPS, even when nearly half the measures suffered from NLOS or other coarse errors.

  7. Robust Estimator for Non-Line-of-Sight Error Mitigation in Indoor Localization

    Science.gov (United States)

    Casas, R.; Marco, A.; Guerrero, J. J.; Falcó, J.

    2006-12-01

    Indoor localization systems are undoubtedly of interest in many application fields. Like outdoor systems, they suffer from non-line-of-sight (NLOS) errors which hinder their robustness and accuracy. Though many ad hoc techniques have been developed to deal with this problem, unfortunately most of them are not applicable indoors due to the high variability of the environment (movement of furniture and of people, etc.). In this paper, we describe the use of robust regression techniques to detect and reject NLOS measures in a location estimation using multilateration. We show how the least-median-of-squares technique can be used to overcome the effects of NLOS errors, even in environments with little infrastructure, and validate its suitability by comparing it to other methods described in the bibliography. We obtained remarkable results when using it in a real indoor positioning system that works with Bluetooth and ultrasound (BLUPS), even when nearly half the measures suffered from NLOS or other coarse errors.

  8. Robust structural optimization using Gauss-type quadrature formula

    International Nuclear Information System (INIS)

    Lee, Sang Hoon; Seo, Ki Seog; Chen, Shikui; Chen, Wei

    2009-01-01

    In robust design, the mean and variance of design performance are frequently used to measure the design performance and its robustness under uncertainties. In this paper, we present the Gauss-type quadrature formula as a rigorous method for mean and variance estimation involving arbitrary input distributions and further extend its use to robust design optimization. One dimensional Gauss-type quadrature formula are constructed from the input probability distributions and utilized in the construction of multidimensional quadrature formula such as the Tensor Product Quadrature (TPQ) formula and the Univariate Dimension Reduction (UDR) method. To improve the efficiency of using it for robust design optimization, a semi-analytic design sensitivity analysis with respect to the statistical moments is proposed. The proposed approach is applied to a simple bench mark problems and robust topology optimization of structures considering various types of uncertainty.

  9. Robust structural optimization using Gauss-type quadrature formula

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hoon; Seo, Ki Seog [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Chen, Shikui; Chen, Wei [Northwestern University, Illinois (United States)

    2009-07-01

    In robust design, the mean and variance of design performance are frequently used to measure the design performance and its robustness under uncertainties. In this paper, we present the Gauss-type quadrature formula as a rigorous method for mean and variance estimation involving arbitrary input distributions and further extend its use to robust design optimization. One dimensional Gauss-type quadrature formula are constructed from the input probability distributions and utilized in the construction of multidimensional quadrature formula such as the Tensor Product Quadrature (TPQ) formula and the Univariate Dimension Reduction (UDR) method. To improve the efficiency of using it for robust design optimization, a semi-analytic design sensitivity analysis with respect to the statistical moments is proposed. The proposed approach is applied to a simple bench mark problems and robust topology optimization of structures considering various types of uncertainty.

  10. Robust Structural Optimization Using Gauss-type Quadrature Formula

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hoon; Seo, Ki Seog; Chen, Shikui; Chen, Wei [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-08-15

    In robust design, the mean and variance of design performance are frequently used to measure the design performance and its robustness under uncertainties. In this paper, we present the Gauss-type quadrature formula as a rigorous method for mean and variance estimation involving arbitrary input distributions and further extend its use to robust design optimization. One dimensional Gauss-type quadrature formula are constructed from the input probability distributions and utilized in the construction of multidimensional quadrature formula such as the tensor product quadrature (TPQ) formula and the univariate dimension reduction (UDR) method. To improve the efficiency of using it for robust design optimization, a semi-analytic design sensitivity analysis with respect to the statistical moments is proposed. The proposed approach is applied to a simple bench mark problems and robust topology optimization of structures considering various types of uncertainty.

  11. Robust Structural Optimization Using Gauss-type Quadrature Formula

    International Nuclear Information System (INIS)

    Lee, Sang Hoon; Seo, Ki Seog; Chen, Shikui; Chen, Wei

    2009-01-01

    In robust design, the mean and variance of design performance are frequently used to measure the design performance and its robustness under uncertainties. In this paper, we present the Gauss-type quadrature formula as a rigorous method for mean and variance estimation involving arbitrary input distributions and further extend its use to robust design optimization. One dimensional Gauss-type quadrature formula are constructed from the input probability distributions and utilized in the construction of multidimensional quadrature formula such as the tensor product quadrature (TPQ) formula and the univariate dimension reduction (UDR) method. To improve the efficiency of using it for robust design optimization, a semi-analytic design sensitivity analysis with respect to the statistical moments is proposed. The proposed approach is applied to a simple bench mark problems and robust topology optimization of structures considering various types of uncertainty

  12. Robust non-wetting PTFE surfaces by femtosecond laser machining.

    Science.gov (United States)

    Liang, Fang; Lehr, Jorge; Danielczak, Lisa; Leask, Richard; Kietzig, Anne-Marie

    2014-08-08

    Nature shows many examples of surfaces with extraordinary wettability,which can often be associated with particular air-trapping surface patterns. Here,robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE). The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters,both of which make it a strong candidate for industrial applications.

  13. Robust Non-Wetting PTFE Surfaces by Femtosecond Laser Machining

    Directory of Open Access Journals (Sweden)

    Fang Liang

    2014-08-01

    Full Text Available Nature shows many examples of surfaces with extraordinary wettability, which can often be associated with particular air-trapping surface patterns. Here, robust non-wetting surfaces have been created by femtosecond laser ablation of polytetrafluoroethylene (PTFE. The laser-created surface structure resembles a forest of entangled fibers, which support structural superhydrophobicity even when the surface chemistry is changed by gold coating. SEM analysis showed that the degree of entanglement of hairs and the depth of the forest pattern correlates positively with accumulated laser fluence and can thus be influenced by altering various laser process parameters. The resulting fibrous surfaces exhibit a tremendous decrease in wettability compared to smooth PTFE surfaces; droplets impacting the virgin or gold coated PTFE forest do not wet the surface but bounce off. Exploratory bioadhesion experiments showed that the surfaces are truly air-trapping and do not support cell adhesion. Therewith, the created surfaces successfully mimic biological surfaces such as insect wings with robust anti-wetting behavior and potential for antiadhesive applications. In addition, the fabrication can be carried out in one process step, and our results clearly show the insensitivity of the resulting non-wetting behavior to variations in the process parameters, both of which make it a strong candidate for industrial applications.

  14. Robust free-space optical communication for indoor information environment

    Science.gov (United States)

    Nakada, Toyohisa; Itoh, Hideo; Kunifuji, Susumu; Nakashima, Hideyuki

    2003-10-01

    The purpose of our study is to establish a robust communication, while keeping security and privacy, between a handheld communicator and the surrounding information environment. From the viewpoint of low power consumption, we have been developing a reflectivity modulating communication module composed of a liquid crystal light modulator and a corner-reflecting mirror sheet. We installed a corner-reflecting sheet instead of light scattering sheet in a handheld videogame machine with a display screen with a reflection-type liquid crystal. Infrared (IR) LED illuminator attached next to the IR camera of a base station illuminates all the room, and the terminal send their data to the base station by switching ON and OFF of the reflected IR beam. Intensity of reflected light differs with the position and the direction of the terminal, and sometimes the intensity of OFF signal at a certain condition is brighter than that of ON signal at another condition. To improve the communication quality, use of machine learning technique is a possibility of the solution. In this paper, we compare various machine learning techniques for the purpose of free space optical communication, and propose a new algorithm that improves the robustness of the data link. Evaluation using an actual free-space communication system is also described.

  15. Perspective: Evolution and detection of genetic robustness

    NARCIS (Netherlands)

    Visser, de J.A.G.M.; Hermisson, J.; Wagner, G.P.; Ancel Meyers, L.; Bagheri-Chaichian, H.; Blanchard, J.L.; Chao, L.; Cheverud, J.M.; Elena, S.F.; Fontana, W.; Gibson, G.; Hansen, T.F.; Krakauer, D.; Lewontin, R.C.; Ofria, C.; Rice, S.H.; Dassow, von G.; Wagner, A.; Whitlock, M.C.

    2003-01-01

    Robustness is the invariance of phenotypes in the face of perturbation. The robustness of phenotypes appears at various levels of biological organization, including gene expression, protein folding, metabolic flux, physiological homeostasis, development, and even organismal fitness. The mechanisms

  16. Fast Kalman Filtering for Relative Spacecraft Position and Attitude Estimation for the Raven ISS Hosted Payload

    Science.gov (United States)

    Galante, Joseph M.; Van Eepoel, John; D'Souza, Chris; Patrick, Bryan

    2016-01-01

    The Raven ISS Hosted Payload will feature several pose measurement sensors on a pan/tilt gimbal which will be used to autonomously track resupply vehicles as they approach and depart the International Space Station. This paper discusses the derivation of a Relative Navigation Filter (RNF) to fuse measurements from the different pose measurement sensors to produce relative position and attitude estimates. The RNF relies on relative translation and orientation kinematics and careful pose sensor modeling to eliminate dependence on orbital position information and associated orbital dynamics models. The filter state is augmented with sensor biases to provide a mechanism for the filter to estimate and mitigate the offset between the measurements from different pose sensors

  17. Does the age-related positivity effect in autobiographical recall reflect differences in appraisal or memory?

    Science.gov (United States)

    Schryer, Emily; Ross, Michael

    2014-07-01

    Two studies examined the extent to which the age-related positivity effect in autobiographical recall is the result of age differences in appraisal and memory. In Study 1, older and younger participants reported 1 pleasant and 1 unpleasant event for 5 days. Participants attempted to recall those events a week later. In Study 2, older and younger participants imagined that positive, negative, and neutral hypothetical events had occurred either to themselves or to an acquaintance and were later asked to recall those events. In Study 1, younger adults reported a complete set of positive and negative events. Older adults reported a pleasant event each day, but 38% did not report an unpleasant event on at least 1 day. A week later, older and younger adults were equally likely to recall the events they had reported. In Study 2, older adults who imagined events happened to themselves rated events as more positive in valence than younger adults did. Older and younger adults were equally likely to remember pleasant and unpleasant events at the end of the study. The data suggest that the age-related positivity effect resides in the appraisal rather than the recall of autobiographical events. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Emergence of robustness in networks of networks

    Science.gov (United States)

    Roth, Kevin; Morone, Flaviano; Min, Byungjoon; Makse, Hernán A.

    2017-06-01

    A model of interdependent networks of networks (NONs) was introduced recently [Proc. Natl. Acad. Sci. (USA) 114, 3849 (2017), 10.1073/pnas.1620808114] in the context of brain activation to identify the neural collective influencers in the brain NON. Here we investigate the emergence of robustness in such a model, and we develop an approach to derive an exact expression for the random percolation transition in Erdös-Rényi NONs of this kind. Analytical calculations are in agreement with numerical simulations, and highlight the robustness of the NON against random node failures, which thus presents a new robust universality class of NONs. The key aspect of this robust NON model is that a node can be activated even if it does not belong to the giant mutually connected component, thus allowing the NON to be built from below the percolation threshold, which is not possible in previous models of interdependent networks. Interestingly, the phase diagram of the model unveils particular patterns of interconnectivity for which the NON is most vulnerable, thereby marking the boundary above which the robustness of the system improves with increasing dependency connections.

  19. Robust Automatic Speech Recognition Features using Complex Wavelet Packet Transform Coefficients

    Directory of Open Access Journals (Sweden)

    TjongWan Sen

    2009-11-01

    Full Text Available To improve the performance of phoneme based Automatic Speech Recognition (ASR in noisy environment; we developed a new technique that could add robustness to clean phonemes features. These robust features are obtained from Complex Wavelet Packet Transform (CWPT coefficients. Since the CWPT coefficients represent all different frequency bands of the input signal, decomposing the input signal into complete CWPT tree would also cover all frequencies involved in recognition process. For time overlapping signals with different frequency contents, e. g. phoneme signal with noises, its CWPT coefficients are the combination of CWPT coefficients of phoneme signal and CWPT coefficients of noises. The CWPT coefficients of phonemes signal would be changed according to frequency components contained in noises. Since the numbers of phonemes in every language are relatively small (limited and already well known, one could easily derive principal component vectors from clean training dataset using Principal Component Analysis (PCA. These principal component vectors could be used then to add robustness and minimize noises effects in testing phase. Simulation results, using Alpha Numeric 4 (AN4 from Carnegie Mellon University and NOISEX-92 examples from Rice University, showed that this new technique could be used as features extractor that improves the robustness of phoneme based ASR systems in various adverse noisy conditions and still preserves the performance in clean environments.

  20. Framework for Robustness Assessment of Timber Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2011-01-01

    This paper presents a theoretical framework for the design and analysis of robustness of timber structures. This is actualized by a more4 frequent use of advanced types of timber structures with limited redundancy and serious consequences in the case of failure. Combined with increased requirements...... to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of new structures essential. Further, the collapse of the Ballerup Super Arena, the bad Reichenhall Ice-Arena and a number of other structural systems during the last 10 years has...... increased the interest in robustness. Typically, modern structural design codes require that ‘the consequence of damages to structures should not be disproportional to the causes of the damages’. However, although the importance of robustness for structural design is widely recognized, the code requirements...