Novel fuzzy logic controllers with self-tuning capability

Two controllers which extend the PD+I fuzzy logic controller to deal with the plant having time varying nonlinear dynamics are proposed. The adaptation ability of the first self tuning PD+I fuzzy logic controller (STPD+I_31) is achieved by adjusting the output scaling factor automatically thereby contributing to significant improvement in performance. Second controller (STPD+I_9) is the simplified version of STPD+I_31 which is designed under the imposed constraint that allows only minimum number of rules in the rule bases. The proposed controllers are compared with two classical nonlinear controllers: the pole placement self tuning PID controller and sliding mode controller. All the controllers are applied to the two-links revolute robot for the tracking control. The tracking performance of STPD+I_31 and STPD+I_9 are much better than the pole placement self tuning PID controller during high speed motions while the performance are comparable at low and medium speed. In addition, STPD+I_31 and STPD+I_9 outperform sliding mode controller using same method of comparison study

The effect of crop residue layers on evapotranspiration, growth and yield of irrigated sugarcane†

A layer of harvest residues from the previous crop can reduce wasteful evaporation from the soil surface and thereby increase the efficiency of use of limited water resources for agricultural production. The practice of harvesting sugarcane green and leaving crop residues in the field, as opposed to burning the residue, has been re-adopted in many sugarcane industries worldwide. However, a better understanding of the dynamic impacts of residue layers on various aspects of the cropping system is required to (1) enable the formulation of sets of best management practices for specific production scenarios, and (2) promote the use of residue layers in areas where it is desirable and has not been adopted, such as irrigated sugarcane production in South Africa. The objective of this study, therefore, was to quantify the effect of 2 different types of residue layers on crop growth, cane yield and evapotranspiration of fully irrigated sugarcane. A layer of cane tops and dead leaves (Trash) and a layer of green tops (Tops) were applied to the soil surface of sugarcane crops (plant crop and first ratoon crop of variety N14) grown on lysimeters at Pongola, South Africa. Observations of crop growth (stalk population, stalk height, canopy cover), cane yield and evapotranspiration for these treatments were compared to that of a bare soil treatment. The data were also used to derive values of crop evaporation coefficients for different development phases and these were compared to FAO56 recommendations. Initial stalk population in the plant crop and radiation capture in the plant and ratoon crop were affected negatively by crop residue layers, but without significantly reducing final stalk population and cane yield. Peak stalk population occurred later in crops grown in residue layers, but peak and final stalk populations were unaffected. Evapotranspiration was reduced by both residue layers, mainly due to a slower developing canopy (reduced transpiration) and reduced evaporation from the soil, during the pre-canopy phases. Increased drainage was observed under residue layers, emphasising the importance of accurate irrigation scheduling to avoid water logging. The FAO56 methodology for calculating crop evaporation coefficient values for the initial, development and late season phases are supported by the results obtained here. Crop evaporation coefficient values were significantly reduced by residue layers. It is important that irrigation scheduling practices be adjusted to realise the potential water savings of sugarcane production systems that make use of residue layers. This study provides the information required to do that. The information could also be used to improve the ability of the crop models to accurately simulate crop growth and evapotranspiration in a residue layer cropping system.Keywords: water use, irrigation, stalk population, canopy development, lysimeter, crop evaporation coefficient, trash blanke

Interdependent network reciprocity in evolutionary games

Besides the structure of interactions within networks, also the interactions between networks are of the outmost importance. We therefore study the outcome of the public goods game on two interdependent networks that are connected by means of a utility function, which determines how payoffs on both networks jointly influence the success of players in each individual network. We show that an unbiased coupling allows the spontaneous emergence of interdependent network reciprocity, which is capable to maintain healthy levels of public cooperation even in extremely adverse conditions. The mechanism, however, requires simultaneous formation of correlated cooperator clusters on both networks. If this does not emerge or if the coordination process is disturbed, network reciprocity fails, resulting in the total collapse of cooperation. Network interdependence can thus be exploited effectively to promote cooperation past the limits imposed by isolated networks, but only if the coordination between the interdependent networks is not disturbe

Mesoscopic structure conditions the emergence of cooperation on social networks

We study the evolutionary Prisoner's Dilemma on two social networks obtained from actual relational data. We find very different cooperation levels on each of them that can not be easily understood in terms of global statistical properties of both networks. We claim that the result can be understood at the mesoscopic scale, by studying the community structure of the networks. We explain the dependence of the cooperation level on the temptation parameter in terms of the internal structure of the communities and their interconnections. We then test our results on community-structured, specifically designed artificial networks, finding perfect agreement with the observations in the real networks. Our results support the conclusion that studies of evolutionary games on model networks and their interpretation in terms of global properties may not be sufficient to study specific, real social systems. In addition, the community perspective may be helpful to interpret the origin and behavior of existing networks as well as to design structures that show resilient cooperative behavior.Comment: Largely improved version, includes an artificial network model that fully confirms the explanation of the results in terms of inter- and intra-community structur

Why did Donders, after describing pseudotorsion, deny the existence of ocular counterrolling together with Ruete, Volkmann, von Graefe and von Helmholtz, until Javal reconfirmed its existence?

After the rapid spread of strabismus surgery by total tenotomy, which had been proposed by the orthopedist Louis Stromeyer from Göttingen in 1838 and performed by the plastic surgeon Johann Friedrich Dieffenbach on October 26th and by the ophthalmologist Florent Cunier on October 29th, 1839, brilliant researchers studied the physiology of eye movements, resulting in the laws by Franciscus Cornelis Donders on pseudotorsion in tertiary positions of gaze and by Johann Benedict Listing that each eye position can be reached by rotation about an axis perpendicular to the primary and the new position of gaze. John Hunter had first described ocular counterrolling (OCR) with head tilt in 1786. The anatomist Alexander Friedrich von Hueck inferred from anatomical studies, however, that up to 28.6° OCR would be possible onhead-tilt to right or left shoulder in 1838, and estimated his own OCR seen in a mirror at approximately 25°. Donders, Christian Georg Theodor Ruete, Alfred Wilhelm Volkmann, Albrecht von Graefe and Hermann von Helmholtz subsequently denied the existence of OCR for many years and thought that only pseudotorsion existed. Louis Emile Javal had myopia and astigmatism, and he re-established the existence of OCR in 1867 when he noticed that, on head tilt to either shoulder, the axis of astigmatism of his eyes no longer coincided with the axis of astigmatism of his glasses

Is there such a thing as a family constitution? A test based on credit rationing

The paper tests the hypothesis that private transfers can be explained by the existence of self-enforcing family constitutions prescribing the minimum level at which a person in middle life should support her young children and elderly parents. The test is based on the effect of a binding credit ration on the probability of making a money transfer, which can be positive only in the presence of family constitutions. Allowing for the possible endogeneity of the credit ration, we find that rationing has a positive effect on the probability of giving money if the potential giver is under the age of retirement, but no significant effect if the person is already retired. This appears to reject the hypothesis that transfer behavior is the outcome of unfettered individual optimization on the part of either altruistic or exchange motivated agents, but not the one that individuals optimize subject to a self-enforcing family constitution. The policy implications are briefly discusse

Fiber Orientation Estimation Guided by a Deep Network

Diffusion magnetic resonance imaging (dMRI) is currently the only tool for noninvasively imaging the brain's white matter tracts. The fiber orientation (FO) is a key feature computed from dMRI for fiber tract reconstruction. Because the number of FOs in a voxel is usually small, dictionary-based sparse reconstruction has been used to estimate FOs with a relatively small number of diffusion gradients. However, accurate FO estimation in regions with complex FO configurations in the presence of noise can still be challenging. In this work we explore the use of a deep network for FO estimation in a dictionary-based framework and propose an algorithm named Fiber Orientation Reconstruction guided by a Deep Network (FORDN). FORDN consists of two steps. First, we use a smaller dictionary encoding coarse basis FOs to represent the diffusion signals. To estimate the mixture fractions of the dictionary atoms (and thus coarse FOs), a deep network is designed specifically for solving the sparse reconstruction problem. Here, the smaller dictionary is used to reduce the computational cost of training. Second, the coarse FOs inform the final FO estimation, where a larger dictionary encoding dense basis FOs is used and a weighted l1-norm regularized least squares problem is solved to encourage FOs that are consistent with the network output. FORDN was evaluated and compared with state-of-the-art algorithms that estimate FOs using sparse reconstruction on simulated and real dMRI data, and the results demonstrate the benefit of using a deep network for FO estimation.Comment: A shorter version is accepted by MICCAI 201

Cervical Ganglioneuroma in Pediatric Age: A Case Report

Ganglioneuroma is a rare, benign, non-invasive tumor emerging from the sympathetic system. Of these tumors, only 8% occur in the neck. In this report, we present a case of a 13-year-old girl with a 2-year history of enlarging neck mass. Her only complaint, aside from neck swelling, was dysphagia. Physical and radiological examinations revealed a large mass centered in the right carotid space. A transcervical approach was used to excise the tumor emerging from the sympathetic ganglia. The patient developed temporary Horner's syndrome postoperatively. In a few weeks, she was completely asymptomatic. Histological examination was compatible with ganglioneuroma. Surgical excision is the only definite treatment of cervical ganglioneuroma and is also the only way to confirm the diagnosis. Injury during surgery may result in significant morbidity.info:eu-repo/semantics/publishedVersio