The relationship of ethnicity, socio-economic factors and malnutrition in primary school children in North of Iran: A cross-sectional study

related factors based on three ethnic groups among primary school children in north of Iran in 2010. Methods: This cross-sectional study was carried out through multistage cluster random sampling on 5698 subjects (2505 Fars-native, 2154 Turkman, and 1039 Sistani) in 112 schools. Well-trained staffs completed the questionnaire and measured students' weight and height. Malnutrition estimated the Z-score less than -2SD for underweight, stunting and wasting were calculated using the cutoffs from WHO references. Results: Generally, malnutrition was observed in 3.20%, 4.93% and 5.13% based on underweight, stunting and wasting respectively. It was more common in girls than in boys and in Sistani than in other ethnic groups. The correlation between malnutrition based on underweight and stunting and ethnicity was statisti-cally significant (P=0.001). Results of logistic regression analyses showed that the risk of malnutrition was in rural area 1.34 times more than urban area, in girls 1.17 times more than boys, in Sistani ethnic group 1.82 times more than Fars-native ethnic group, in low economic families 2.01 times more than high economic families. Conclusion: Underweight, stunting and wasting are the health problems in primary school children in north of Iran with a higher prevalence in girls, in rural areas, and in Sistani ethnic group

Application of Complex-Valued FXLMS Adaptive Filter to Fourier Basis Control of Adaptive Optics

In this paper, the Filtered-X Least Mean Square (FXLMS) adaptive filter with bias integration technique is applied to an adaptive optics system where the Discrete Fourier Transform is used to project the measured phase onto the Fourier basis for modal control. The control law is applied in the complex-valued coefficient space and the FXLMS algorithm is modified accordingly for the complex-valued control. Numerical analysis is conducted for a feedback loop of a single Fourier mode in the presence of a disturbance representing a frozen flow atmospheric turbulence. The performance is compared with a Kalman estimator based control law proposed in the literature called Predictive Fourier Control (PFC). The proposed method demonstrated a similar performance for a stationary disturbance and improved performance for a slowly drifting disturbance. Whereas the performance of the PFC is very sensitive to the accuracy of the identification of the disturbance, the proposed method does not require such an explicit identification and produces minimum error for the given disturbance

Use of an Least Mean Squares Filter in the Control of Optical Beam Jitter

The article of record as published may be found at http://dx.doi.org/10.2514/1.26778Meeting optical beam jitter requirements is becoming a challenging problem for several space programs. A laser beam jitter control test bed has been developed at the Naval Postgraduate School to develop improved jitter control techniques. Several control techniques, such as least means squares and linear–quadratic regulator were applied for jitter control. Enhancement in least means squares techniques to improve convergence rate was achieved by adding an adaptive biasfilter to the reference signal. In the experiments, the platform is vibrated at 50 and 87 Hz. In addition, a fast steering mirror is used to inject a random component of 200 Hz band-limited white noise. The experimental results demonstrated that the addition of the adaptive bias filter to the least means squares algorithm significantly increased the converging rate of the controller. To achieve the reduction of both sinusoidal and random jitter, a combination of least means squares/adaptive bias filter and linear–quadratic regulator is most effective. The least means squares/adaptive bias filter control is most effective for a sinusoidal jitter and the linear–quadratic regulator control for a random jitter

Rest-to-Rest Slew Maneuver of Three-Axis Rotational Flexible Spacecraft

The article of record as published may be found at http://dx.doi.org/10.3182/20080706-5-KR-1001.02040This paper presents a slew maneuver control design of three-axis rotational flexible spacecraft. The focus of the work is to investigate the nonlinear effect of the three axis maneuver for a flexible spacecraft when a vibration suppression technique for linear systems such as input shaping is used in the control design. A simple method of slewing three-axis rotational spacecraft using input shaping is proposed and the proposed technique is implemented on an experimental three-axis spacecraft simulator. This paper presents a slew maneuver control design of three-axis rotational flexible spacecraft. The focus of the work is to investigate the nonlinear effect of the three axis maneuver for a flexible spacecraft when a vibration suppression technique for linear systems such as input shaping is used in the control design. A simple method of slewing three-axis rotational spacecraft using input shaping is proposed and the proposed technique is implemented on an experimental three-axis spacecraft simulator. This paper presents a slew maneuver control design of three-axis rotational flexible spacecraft. The focus of the work is to investigate the nonlinear effect of the three axis maneuver for a flexible spacecraft when a vibration suppression technique for linear systems such as input shaping is used in the control design. A simple method of slewing three-axis rotational spacecraft using input shaping is proposed and the proposed technique is implemented on an experimental three-axis spacecraft simulator. This paper presents a slew maneuver control design of three-axis rotational flexible spacecraft. The focus of the work is to investigate the nonlinear effect of the three axis maneuver for a flexible spacecraft when a vibration suppression technique for linear systems such as input shaping is used in the control design. A simple method of slewing three-axis rotational spacecraft using input shaping is proposed and the proposed technique is implemented on an experimental three-axis spacecraft simulator

A Generalized Second Order Compensator Design for Vibration Control of Flexible Structures

The article of record as published may be found at http://dx.doi.org/10.2514/6.1994-1626In this paper, a modified positive position feedback compensator design is presented for vibration control of flexible structures. The new method provides extended capability of controlling structural natural frequencies and damping. A similar compensator design where only rate sensors are available is also discussed. Ahalytical and experimental results are presented to verify the proposed method

Experimental Verification of Attitude Control Techniques for Slew Maneuvers of Flexible Spacecraft

The article of record as published may be found at http://dx.doi.org/10.2514/6.1992-4456This paper presents experimental verification of modern and classical control laws on flexible spacecraft structures. The Flexible Spacecraft Simulator at the Naval Postgraduate School is designed to test a variety of control theory on a two-dimensional representation of an antenna at the end of a low-frequency astromast. The Simulator represents motion about the pitch axis and is restricted to rotatation only. Control laws are implemented through a momentum wheel mounted on the rigid main body. Feedback is obtained through a rotary variable differential transformer (RVDT) which senses the body's rotation angle and a rate-gyro giving body rate. The analytical model contains the linearized equations of motion accounting for the flexible dynamics. Slewing maneuvers are conducted for positioning the main body by using proportional- derivative (PD), torque profiles and optimal controllers. No active control is applied to the flexible structure. A new technique for state estimation is developed for the optimal controller since the standard estimation methods prove to be unsatisfactory. In all cases, the experimental results are in close agreement with the analytical predictions. This paper presents experimental verification of modern and classical control laws on flexible spacecraft structures. The Flexible Spacecraft Simulator at the Naval Postgraduate School is designed to test a variety of control theory on a two-dimensional representation of an antenna at the end of a low-frequency astromast. The Simulator represents motion about the pitch axis and is restricted to rotatation only. Control laws are implemented through a momentum wheel mounted on the rigid main body. Feedback is obtained through a rotary variable differential transformer (RVDT) which senses the body's rotation angle and a rate-gyro giving body rate. The analytical model contains the linearized equations of motion accounting for the flexible dynamics. Slewing maneuvers are conducted for positioning the main body by using proportional- derivative (PD), torque profiles and optimal controllers. No active control is applied to the flexible structure. A new technique for state estimation is developed for the optimal controller since the standard estimation methods prove to be unsatisfactory. In all cases, the experimental results are in close agreement with the analytical predictions. This paper presents experimental verification of modern and classical control laws on flexible spacecraft structures. The Flexible Spacecraft Simulator at the Naval Postgraduate School is designed to test a variety of control theory on a two-dimensional representation of an antenna at the end of a low-frequency astromast. The Simulator represents motion about the pitch axis and is restricted to rotatation only. Control laws are implemented through a momentum wheel mounted on the rigid main body. Feedback is obtained through a rotary variable differential transformer (RVDT) which senses the body's rotation angle and a rate-gyro giving body rate. The analytical model contains the linearized equations of motion accounting for the flexible dynamics. Slewing maneuvers are conducted for positioning the main body by using proportional- derivative (PD), torque profiles and optimal controllers. No active control is applied to the flexible structure. A new technique for state estimation is developed for the optimal controller since the standard estimation methods prove to be unsatisfactory. In all cases, the experimental results are in close agreement with the analytical predictions. This paper presents experimental verification of modern and classical control laws on flexible spacecraft structures. The Flexible Spacecraft Simulator at the Naval Postgraduate School is designed to test a variety of control theory on a two-dimensional representation of an antenna at the end of a low-frequency astromast. The Simulator represents motion about the pitch axis and is restricted to rotatation only. Control laws are implemented through a momentum wheel mounted on the rigid main body. Feedback is obtained through a rotary variable differential transformer (RVDT) which senses the body's rotation angle and a rate-gyro giving body rate. The analytical model contains the linearized equations of motion accounting for the flexible dynamics. Slewing maneuvers are conducted for positioning the main body by using proportional- derivative (PD), torque profiles and optimal controllers. No active control is applied to the flexible structure. A new technique for state estimation is developed for the optimal controller since the standard estimation methods prove to be unsatisfactory. In all cases, the experimental results are in close agreement with the analytical predictions

Optical Beam Jitter Control for NPS HEL Beam Control Testbed

In this paper, an optical beam jitter control method for the Naval Postgraduate School HEL beam control testbed is presented. Additional hardware is developed and integrated on the testbed to realize the strap-down IRU jitter compensation architectures. Feedforward control design of the strap-down IRU design is studied and tested on the testbed. An adaptive filtering method for narrow-field-of-view video tracker jitter correction is also presented. In this paper, an optical beam jitter control method for the Naval Postgraduate School HEL beam control testbed is presented. Additional hardware is developed and integrated on the testbed to realize the strap-down IRU jitter compensation architectures. Feedforward control design of the strap-down IRU design is studied and tested on the testbed. An adaptive filtering method for narrow-field-of-view video tracker jitter correction is also presented

Vibration Suppression of a Spacecraft Flexible Appendages Using Smart Material

The article of record as published may be found at http://dx.doi.org/10..1088/0964-1726/7/1/011This paper presents the results of positive position feedback (PPF) control and linear–quadratic Gaussian (LQG) control for vibration suppression of a flexible structure using piezoceramics. Experiments were conducted on the US Naval Postgraduate School’s flexible spacecraft simulator (FSS), which is comprised of a rigid central body and a flexible appendage. The objective of this research is to suppress the vibration of the flexible appendage. Experiments show that both control methods have unique advantages for vibration suppression. PPF control is effective in providing high damping for a particular mode and is easy to implement. LQG control provides damping to all modes; however, it cannot provide high damping for a specific mode. LQG control is very effective in meeting specific requirements, such as minimization of tip motion of a flexible beam, but at a higher implementation cost.This paper presents the results of positive position feedback (PPF) control and linear–quadratic Gaussian (LQG) control for vibration suppression of a flexible structure using piezoceramics. Experiments were conducted on the US Naval Postgraduate School’s flexible spacecraft simulator (FSS), which is comprised of a rigid central body and a flexible appendage. The objective of this research is to suppress the vibration of the flexible appendage. Experiments show that both control methods have unique advantages for vibration suppression. PPF control is effective in providing high damping for a particular mode and is easy to implement. LQG control provides damping to all modes; however, it cannot provide high damping for a specific mode. LQG control is very effective in meeting specific requirements, such as minimization of tip motion of a flexible beam, but at a higher implementation cost.This paper presents the results of positive position feedback (PPF) control and linear–quadratic Gaussian (LQG) control for vibration suppression of a flexible structure using piezoceramics. Experiments were conducted on the US Naval Postgraduate School’s flexible spacecraft simulator (FSS), which is comprised of a rigid central body and a flexible appendage. The objective of this research is to suppress the vibration of the flexible appendage. Experiments show that both control methods have unique advantages for vibration suppression. PPF control is effective in providing high damping for a particular mode and is easy to implement. LQG control provides damping to all modes; however, it cannot provide high damping for a specific mode. LQG control is very effective in meeting specific requirements, such as minimization of tip motion of a flexible beam, but at a higher implementation cost

Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV

The absolute muon flux between 20 GeV and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0 degree to 58 degree. Due to the large exposure of about 150 m2 sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3 % at 150 GeV in the vertical direction is achieved. The ratio of positive to negative muons is studied between 20 GeV and 500 GeV, and the average vertical muon charge ratio is found to be 1.285 +- 0.003 (stat.) +- 0.019 (syst.).Comment: Total 32 pages, 9Figure

Trends and transitions in the institutional environment for public and private science

The last quarter-century bore witness to a sea change in academic involvement with commerce. Widespread university-based efforts to identify, manage, and market intellectual property (IP) have accompanied broad shifts in the relationship between academic and proprietary approaches to the dissemination and use of science and engineering research. Such transformations are indicators of institutional changes at work in the environment faced by universities. This paper draws upon a fifteen-year panel (1981–1995) of university-level data for 87 research-intensive US campuses in order to document trends and transitions in relationships among multiple indicators of academic and commercial engagement. The institutional environment for public and private science is volatile, shifting in fits and starts from a situation conducive to organizational learning through high volume patenting to a more challenging arrangement that links indiscriminate pursuit of IP with declines in both the volume and impact of academic science. The pattern and timing of these transitions may support an enduring system of stratification that offers increasing returns to first-movers while limiting the opportunities available to universities that are later entrants to the commercial realm. Unpacking the systematic effects of university research commercialization requires focused attention on the sources and trajectories of profound institutional change.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42839/1/10734_2004_Article_2916.pd