Idiotypic Immune Networks in Mobile Robot Control

Jerne's idiotypic network theory postulates that the immune response involves inter-antibody stimulation and suppression as well as matching to antigens. The theory has proved the most popular Artificial Immune System (AIS) model for incorporation into behavior-based robotics but guidelines for implementing idiotypic selection are scarce. Furthermore, the direct effects of employing the technique have not been demonstrated in the form of a comparison with non-idiotypic systems. This paper aims to address these issues. A method for integrating an idiotypic AIS network with a Reinforcement Learning based control system (RL) is described and the mechanisms underlying antibody stimulation and suppression are explained in detail. Some hypotheses that account for the network advantage are put forward and tested using three systems with increasing idiotypic complexity. The basic RL, a simplified hybrid AIS-RL that implements idiotypic selection independently of derived concentration levels and a full hybrid AIS-RL scheme are examined. The test bed takes the form of a simulated Pioneer robot that is required to navigate through maze worlds detecting and tracking door markers.

Abordagem multimetodológica do impacto da mentoria e relações de ajuda no processo informal de employee branding: o efeito de marca de empregado

O processo de employee branding tem demonstrado promover e reforçar o contrato psicológico entre os colaboradores e a organização, pelo incremento e potenciação do sentimento de comprometimento e lealdade do colaborador de acordo com Miles e Mangold. Esta investigação foca-se no estudo do impacto da mentoria e relações de ajuda no processo de employee branding, numa visão integrada da gestão de recursos humanos e do comportamento organizacional, com base nas relações de troca do marketing do relacionamento numa perspetiva da gestão por competências e foco nas Pessoas. Com a introdução da nova variável (mentoria e relações de ajuda) esta investigação, ao enriquecer e incrementar o processo de employee branding de Miles e Mangold proposto em 2004 e 2005, apresenta a construção de um instrumento de diagnóstico do inovador processo de Efeito de Marca de Empregado. A investigação decorreu em 30 organizações, com um total de 725 questionários, que permitiu a validação e fiabilidade do instrumento, bem como demonstra através de métodos estatísticos a influência das ações de mentoria e relações de ajuda e da atuação das relações interpessoais que promovem o processo employee branding. Se o processo de employee branding já incrementava os resultados organizacionais, com esta investigação, pode-se afirmar que o processo de Efeito de Marca de Empregado não só incrementa como também impulsiona a imagem de marca da organização pela atuação dinâmica e catalisadora das relações interpessoais dos seus colaboradores, dentro e fora da organização, com a introdução e promoção de ações mentoria e relações de ajuda entre chefias e chefiados; ABSTRACT: The employee branding process has shown as to promote and strengthen the psychological contract between employees and the organization, by increasing and maximizing the sense of employees’ commitment and loyalty, according with Miles and Mangold. This research focuses on the impact of mentoring and helping relationships in the employee branding process, in an integrated view of human resources management and organizational behavior, based on the exchange ratio of the relationship marketing in a perspective of management by competencies and people focused approach. With the introduction of the new variable (mentoring and helping relationships), this research enriches and enhances the Miles and Mangold employee branding process proposed in 2004 and 2005 and presents the construction of an diagnostic instrument for the innovative process of Employee Brand Effect. This research took place in 30 organizations with a total of 725 questionnaires, which allowed the validation and reliability of the instrument and the evidence through statistical methods of the influence of mentoring and helping relationships actions and of the interaction of interpersonal relationships promoting the employee branding process. If the employee branding process was already boosting organizational results with this research, it can be stated that the Employee Brand Effect process not only increases, but also boosts the organization’s brand image by the actuation of the dynamics of employees’ interpersonal relationships, inside and outside the organization, with the introduction and promotion of mentoring and helping relationships actions between leaders and followers.

Photo-cross-linked poly(D,L-lactide)-based networks. Structural characterization by HR-MAS NMR spectroscopy and hydrolytic degradation behavior

To date, biodegradable networks and particularly their kinetic chain lengths have been characterized by analysis of their degradation products in solution. We characterize the network itself by NMR analysis in the solvent-swollen state under magic angle spinning conditions. The networks were prepared by photoinitiated cross-linking of poly(dl-lactide)−dimethacrylate macromers (5 kg/mol) in the presence of an unreactive diluent. Using diffusion filtering and 2D correlation spectroscopy techniques, all network components are identified. By quantification of network-bound photoinitiator fragments, an average kinetic chain length of 9 ± 2 methacrylate units is determined. The PDLLA macromer solution was also used with a dye to prepare computer-designed structures by stereolithography. For these networks structures, the average kinetic chain length is 24 ± 4 methacrylate units. In all cases the calculated molecular weights of the polymethacrylate chains after degradation are maximally 8.8 kg/mol, which is far below the threshold for renal clearance. Upon incubation in phosphate buffered saline at 37 °C, the networks show a similar mass loss profile in time as linear high-molecular-weight PDLLA (HMW PDLLA). The mechanical properties are preserved longer for the PDLLA networks than for HMW PDLLA. The initial tensile strength of 47 ± 2 MPa does not decrease significantly for the first 15 weeks, while HMW PDLLA lost 85 ± 5% of its strength within 5 weeks. The physical properties, kinetic chain length, and degradation profile of these photo-cross-linked PDLLA networks make them most suited materials for orthopedic applications and use in (bone) tissue engineering.

School-based programs for increasing connectedness and reducing risk behavior : a systematic review

School connectedness has a significant impact on adolescent outcomes, including reducing risk taking behavior. This paper critically examines the literature on school-based programs targeting increased connectedness for reductions in risk taking. Fourteen articles describing seven different school-based programs were reviewed. Programs drew on a range of theories to increase school connectedness, and evaluations conducted for the majority of programs demonstrated positive changes in school connectedness, risk behavior, or a combination of the two. Many of the reviewed programs involved widespread school system change, however, which is frequently a complex and time consuming task. Future research is needed to examine the extent of intervention complexity required to result in change. This review also showed a lack of consistency in definitions and measurement of connectedness as well as few mediation analyses testing assumptions of impact on risk taking behavior through increases in school connectedness. Additionally, this review revealed very limited evaluation of the elements of multi-component programs that are most effective in increasing school connectedness and reducing adolescent risk taking.

Comparative behavior of CdS and CdSe quantum dots in poly(3-hexylthiophene) based nanocomposites

CdS and CdSe nanoparticles have been prepared using conducting poly(3-hexylthiophene) (P3HT) matrix with an objective to understand the effect of nanoparticles on the polymer matrix using electrochemical and spectroscopic techniques. The spectroscopic results reveal that the electronic structure of polymer is strongly influenced by the characteristics of embedded semiconducting nanoparticles. SEM and TEM images show the ordered morphology of the CdS and CdSe nanoparticles in presence of the polymer matrix. Cyclic voltammetry performed both in the presence and absence of light enables us to understand the redox changes in P3HT due to CdS and CdSe quantum dots such as the generation of free radical in the excited state and their electrochemical band gaps.

Parenting and the behavior problems of young children with an intellectual disability: Concurrent and longitudinal relationships in a population-based study

We examined parenting behaviors, and their association with concurrent and later child behavior problems. Children with an intellectual disability (ID) were identified from a UK birth cohort (N  =  516 at age 5). Compared to parents of children without an ID, parents of children with an ID used discipline less frequently, but reported a more negative relationship with their child. Among children with an ID, discipline, and home atmosphere had no long-term association with behavior problems, whereas relationship quality did: closer relationships were associated with fewer concurrent and later child behavior problems. Increased parent-child conflict was associated with greater concurrent and later behavior problems. Parenting programs in ID could target parent-child relationship quality as a potential mediator of behavioral improvements in children.

Investigation of the mechanical behavior of kangaroo humeral head cartilage tissue by a porohyperelastic model based on the strain-rate-dependent permeability

Solid–interstitial fluid interaction, which depends on tissue permeability, is significant to the strain-rate-dependent mechanical behavior of humeral head (shoulder) cartilage. Due to anatomical and biomechanical similarities to that of the human shoulder, kangaroos present a suitable animal model. Therefore, indentation experiments were conducted on kangaroo shoulder cartilage tissues from low (10−4/s) to moderately high (10−2/s) strain-rates. A porohyperelastic model was developed based on the experimental characterization; and a permeability function that takes into account the effect of strain-rate on permeability (strain-rate-dependent permeability) was introduced into the model to investigate the effect of rate-dependent fluid flow on tissue response. The prediction of the model with the strain-rate-dependent permeability was compared with those of the models using constant permeability and strain-dependent permeability. Compared to the model with constant permeability, the models with strain-dependent and strain-rate-dependent permeability were able to better capture the experimental variation at all strain-rates (p<0.05). Significant differences were not identified between models with strain-dependent and strain-rate-dependent permeability at strain-rate of 5×10−3/s (p=0.179). However, at strain-rate of 10−2/s, the model with strain-rate-dependent permeability was significantly better at capturing the experimental results (p<0.005). The findings thus revealed the significance of rate-dependent fluid flow on tissue behavior at large strain-rates, which provides insights into the mechanical deformation mechanisms of cartilage tissues.

Ship collision avoidance and COLREGS compliance using simulation-based control behavior selection with predictive hazard assessment

This paper describes a concept for a collision avoidance system for ships, which is based on model predictive control. A finite set of alternative control behaviors are generated by varying two parameters: offsets to the guidance course angle commanded to the autopilot and changes to the propulsion command ranging from nominal speed to full reverse. Using simulated predictions of the trajectories of the obstacles and ship, compliance with the Convention on the International Regulations for Preventing Collisions at Sea and collision hazards associated with each of the alternative control behaviors are evaluated on a finite prediction horizon, and the optimal control behavior is selected. Robustness to sensing error, predicted obstacle behavior, and environmental conditions can be ensured by evaluating multiple scenarios for each control behavior. The method is conceptually and computationally simple and yet quite versatile as it can account for the dynamics of the ship, the dynamics of the steering and propulsion system, forces due to wind and ocean current, and any number of obstacles. Simulations show that the method is effective and can manage complex scenarios with multiple dynamic obstacles and uncertainty associated with sensors and predictions.

Temperature dependent electrical transport behavior of InN/GaN heterostructure based Schottky diodes

InN/GaN heterostructure based Schottky diodes were fabricated by plasma-assisted molecular beam epitaxy. The temperature dependent electrical transport properties were carried out for InN/GaN heterostructure. The barrier height and the ideality factor of the Schottky diodes were found to be temperature dependent. The temperature dependence of the barrier height indicates that the Schottky barrier height is inhomogeneous in nature at the heterostructure interface. The higher value of the ideality factor and its temperature dependence suggest that the current transport is primarily dominated by thermionic field emission (TFE) other than thermionic emission (TE). The room temperature barrier height obtained by using TE and TFE models were 1.08 and 1.43 eV, respectively. (C) 2011 American Institute of Physics. doi: 10.1063/1.3549685]

A Comparative Study of Electrical Switching Behavior of Certain Tellurium based Chalcogenide Thin Films for Phase Change Memory (PCM) Applications

This work describes the electrical switching behavior of three telluride based amorphous chalcogenide thin film samples, Al-Te, Ge-Se-Te and Ge-Te-Si. These amorphous thin films are made using bulk glassy ingots, prepared by conventional melt quenching technique, using flash evaporation technique; while Al-Te sample has been coated in coplanar electrode geometry, Ge-Se-Te and Ge-Te-Si samples have been deposited with sandwich electrodes. It is observed that all the three samples studied, exhibit memory switching behavior in thin film form, with Ge-Te-Si sample exhibiting a faster switching characteristic. The difference seen in the switching voltages of the three samples studied has been understood on the basis of difference in device geometry and thickness. Scanning electron microscopic image of switched region of a representative Ge15Te81Si4 sample shows a structural change and formation of crystallites in the electrode region, which is responsible for making a conducting channel between the two electrodes during switching.

A Revisit to Capture the Entire Behavior of Ultrasonic Wave Dispersion Characteristics of Single Walled Carbon Nanotubes Based on Nonlocal Elasticity Theory and Flugge Shell Model

In this paper, an ultrasonic wave propagation analysis in single-walled carbon nanotube (SWCNT) is re-studied using nonlocal elasticity theory, to capture the whole behaviour. The SWCNT is modeled using Flugge's shell theory, with the wall having axial, circumferential and radial degrees of freedom and also including small scale effects. Nonlocal governing equations for this system are derived and wave propagation analysis is also carried out. The revisited nonlocal elasticity calculation shows that the wavenumber tends to infinite at certain frequencies and the corresponding wave velocity tends to zero at those frequencies indicating localization and stationary behavior. This frequency is termed as escape frequency. This behavior is observed only for axial and radial waves in SWCNT. It has been shown that the circumferential waves will propagate dispersively at higher frequencies in nonlocality. The magnitudes of wave velocities of circumferential waves are smaller in nonlocal elasticity as compared to local elasticity. We also show that the explicit expressions of cut-off frequency depend on the nonlocal scaling parameter and the axial wavenumber. The effect of axial wavenumber on the ultrasonic wave behavior in SWCNTs is also discussed. The present results are compared with the corresponding results (for first mode) obtained from ab initio and 3-D elastodynamic continuum models. The acoustic phonon dispersion relation predicted by the present model is in good agreement with that obtained from literature. The results are new and can provide useful guidance for the study and design of the next generation of nanodevices that make use of the wave propagation properties of single-walled carbon nanotubes.

Effect of carrier concentration of InN on the transport behavior of InN/GaN heterostructure based Schottky junctions

We present the study involving the dependence of carrier concentration of InN films, grown on GaN templates using the plasma assisted molecular beam epitaxy system, on growth temperature. The influence of InN carrier concentration on the electrical transport behavior of InN/GaN heterostructure based Schottky junctions is also discussed. The optical absorption edge of InN film was found to be strongly dependent on carrier concentration, and was described by Kane's k.p model, with non-parabolic dispersion relation for carrier in the conduction band. The position of the Fermi-level in InN films was modulated by the carrier concentration in the InN films. The barrier height of the heterojunctions as estimated from I-V characteristic was also found to be dependent on the carrier concentration of InN. (C) 2012 Elsevier Ltd. All rights reserved.

Role of dicarboxylate linkers in Mn-III-salicylaldoximate based extended structures: synthesis, structures, and magnetic behavior

Four new oxo-centered Mn-III-salicylaldoximate triangle-based extended complexes (Mn6O2)-O-III(salox)(6)(EtOH)(4)(phda)](n)(saloxH(2))(n)(2H(2)O)(n) (1), (Mn6O2)-O-III(salox)(6)(MeOH)(5)(5-I-isoph)](n)(3MeOH)(n) (2), (Mn6O2)-O-III(salox)(6)(MeOH)(4)(H2O) (5-N-3-isoph)](n)(4MeOH)(n) (3) and (Mn3NaO)-Na-III(salox)(3)(MeOH)(4)(5-NO2-isoph)](n)(MeOH)(n) (H2O)(n) (4) salox=salicylaldoximate, phda=1,3-phenylenediacetate, isoph=isophthalate] have been synthesized under similar reaction conditions. Single crystal X-ray structures show that in 1, only one type of Mn-6 cluster is arranged in 1D, whereas in 2 and 3 there are two types of clusters, differing in the way the triangle units are joined and assembled. In complex4, however, the basic building structure is heteronuclear and based on Mn-3 units extended in 2D. Susceptibility measurements (dc and ac) over a wide range of temperatures and fields show that the complexes1, 2, and 3 behave as single molecule magnets (SMMs) with S=4ground state, while 4 is dominantly antiferromagnetic with a ground spin state S=2. Density functional theory calculations have been performed on model complexes to provide a qualitative theoretical interpretation for their overall magnetic behavior.

Hot deformation behavior of Ni-Fe-Ga-based ferromagnetic shape memory alloy - A study using processing map

Ni-Fe-Ga-based alloys form a new class of ferromagnetic shape memory alloys (FSMAs) that show considerable formability because of the presence of a disordered fcc gamma-phase. The current study explores the deformation processing of this alloy using an off-stoichiometric Ni55Fe59Ga26 alloy that contains the ductile gamma-phase. The hot deformation behavior of this alloy has been characterized on the basis of its flow stress variation obtained by isothermal constant true strain rate compression tests in the 1123-1323 K temperature range and strain rate range of 10(-3)-10 s(-1) and using a combination of constitutive modeling and processing map. The dynamic recrystallization (DRX) regime for thermomechanical processing has been identified for this Heusler alloy on the basis of the processing maps and the deformed microstructures. This alloy also shows evidence of dynamic strain-aging (DSA) effect which has not been reported so far for any Heusler FSMAs. Similar effect is also noticed in a Ni-Mn-Ga-based Heusler alloy which is devoid of any gamma-phase. (C) 2014 Elsevier Ltd. All rights reserved.

Compressive flow behavior of Al-Si based alloy: Role of heat treatment

The flow characteristics of a near eutectic Al-Si based cast alloy have been examined in compression at strain rates varying from 3 x 10(-4) to 10(2) s(-1) and at three different temperatures, i.e., room temperature (RT), 100 degrees C and 200 degrees C. The dependence of the flow behavior on heat treatment is studied by testing the alloy in non-heat treated (NHT) and heat treated (HT) conditions. The heat treatment has strong influence on strain rate sensitivity (SRS), strength and work hardening behavior of the alloy. It is observed that the strength of the alloy increases with increase in strain rate and it increases more rapidly above the strain rate of 10(-1) s(-1) in HT condition at all the temperatures, and at 100 degrees C and 200 degrees C in NHT condition. The thermally dependent process taking place in the HT matrix is responsible for the observed greater SRS in HT condition. The alloy in HT condition exhibits a larger work hardening rate than in NHT condition during initial stages of straining. However, the hardening rate decreases more sharply at higher strains in HT condition due to precipitate shearing and higher rate of Si particle fracture. Thermal hardening is observed at 200 degrees C in NHT condition due to precipitate formation, which results in increased SRS at higher temperatures. Thermal softening is observed in HT condition at 200 C due to precipitate coarsening, which leads to a decrease in SRS at higher temperatures. Stress simulations by a finite element method support the experimentally observed particle and matrix fracture behavior. A negative SRS and serrated flow are observed in the lower strain rate regime (3 x 10(-4)-10(-2) s(-1)) at RT and 100 degrees C, in both NHT and HT conditions. The observations show that both dynamic strain aging (DSA) and precipitate shearing play a role in serrated flow. (C) 2015 Elsevier B.V. All rights reserved.