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Inertial navigation system has drift error in underwater applications. Use of DVL with Kalman filter for position and attitude correction is common. Using velocity data decreases drift error in position estimation but this error exists and increases linearity with time. In this article the navigation system consists of inertial measurement unit (IMU) and a Doppler velocity log (DVL) along with depth sensor. With use of magnetic field measurement and earth magnetic field map a new measurement is generated. Discrete extended Kalman filter with indirect feedback is used for tightly coupled integrated navigation algorithm. This algorithm is based on inertial navigation error dynamics. This paper demonstrates the effectiveness of algorithm through simulation. The procedure of simulation is done by sensor data generation. Arbitrary trajectory with specific kinematic characteristic (linear and angular velocity and acceleration) is generated. Sensor data by adding noise and bias to kinematic characteristic of trajectory is produced. Simulation results reveal that the new algorithm with use of magnetic data and earth magnetic field map decreases the drift error with comparison to conventional INS-DVL integrated navigation algorithm. [ABSTRACT FROM AUTHOR]

Background: The prevalence of constipation in childhood is 0.7% to 29.6%. Inorganic causes are considered as the most common cause of constipation in children. Polyethylene glycol (PEG) is the most effective and safest laxatives which is usable in children in the long-term. This study was conducted to evaluate and compare the effect of PEG treatment and probiotic bacilluscoagulans and bifidobacterium and probiotic to enhance the growth of probiotics. Materials and Methods: In this double blind clinical trial study(interventional study), 120 children aged 2-16 years with chronic functional constipation enrolled the study based on ROME III criteria. The bowels became empty by using liquid paraffin. Then, children were randomly divided into three groups of polyethylene glycol+placebo and Probiotics+placebo and polyethylene glycol+probiotics recipients. After 6 weeks of treatment, treatment success rates between the three groups were compared before and after the study Data analyzed by SPSS 20 software. Results: The results of the study conducted on the three groups for treatment of constipation showed that the effect of polyethylene glycol and probiotic on treatment was considerable before and after treatment; but the levels of effect was similar in the comparison of groups. The simultaneous use of two drugs was more effective than a single drug. Conclusion: Overall, the results of our study showed that concurrent use of polyethylene glycol and probiotics is much more effective in the treatment of constipation. [ABSTRACT FROM AUTHOR]