Adaptive hybrid control of manipulators

Simple methods for the design of adaptive force and position controllers for robot manipulators within the hybrid control architecuture is presented. The force controller is composed of an adaptive PID feedback controller, an auxiliary signal and a force feedforward term, and it achieves tracking of desired force setpoints in the constraint directions. The position controller consists of adaptive feedback and feedforward controllers and an auxiliary signal, and it accomplishes tracking of desired position trajectories in the free directions. The controllers are capable of compensating for dynamic cross-couplings that exist between the position and force control loops in the hybrid control architecture. The adaptive controllers do not require knowledge of the complex dynamic model or parameter values of the manipulator or the environment. The proposed control schemes are computationally fast and suitable for implementation in on-line control with high sampling rates

Adaptive control of dual-arm robots

Three strategies for adaptive control of cooperative dual-arm robots are described. In the position-position control strategy, the adaptive controllers ensure that the end-effector positions of both arms track desired trajectories in Cartesian space despite unknown time-varying interaction forces exerted through the load. In the position-hybrid control strategy, the adaptive controller of one arm controls end-effector motions in the free directions and applied forces in the constraint directions, while the adaptive controller of the other arm ensures that the end-effector tracks desired position trajectories. In the hybrid-hybrid control strategy, the adaptive controllers ensure that both end-effectors track reference position trajectories while simultaneously applying desired forces on the load. In all three control strategies, the cross-coupling effects between the arms are treated as disturbances which are rejected by the adaptive controllers while following desired commands in a common frame of reference. The adaptive controllers do not require the complex mathematical model of the arm dynamics or any knowledge of the arm dynamic parameters or the load parameters such as mass and stiffness. The controllers have simple structures and are computationally fast for on-line implementation with high sampling rates

Biological survey on Penaeus indicus in the Jask area (Oman Sea)

The indian white prawn (Penaeus indicus), as one of the commercially important and dominant species along the East coast of Hormozgan province, is a very potential and prospective candidate species for shrimp farming. Since, there wasn't well enough information about biology of this species from Iranian wateres, therefore. some biological aspects such as growth rate, reproduction behaviour distribution pattern and feeding habits were studied from March 1997 to March 1998. Monthly sampling were carried out from the fishing grounds and estuaries of Jask area in the Oman Sea by small trawlers and beach seines gears. Initial growth 01 male was faster than female, with calculated K=l.5 for male and K=1.3 for female. Isometric growth trend was observed in both sexes. Sexual maturity attained within the first 12 months. Spawners were occured abundantly during post-winter, spring and beginning of summer. Postlarvae and sub-adults were found in the esturies with 25-100 mm length, and high densities were observed around the mangrove's roots. They spend at least 3 to 5 months of their life span in the esturies. Analysis of stomach contents revealed that this species is an omnivore with indicative contents of detritus, polychaetes, crustaceane, bivalves, algae and sand particles, with preponderance of vegetable constituents in the sub-adults and of detritus in adults

Remote surface inspection system

This paper reports on an on-going research and development effort in remote surface inspection of space platforms such as the Space Station Freedom (SSF). It describes the space environment and identifies the types of damage for which to search. This paper provides an overview of the Remote Surface Inspection System that was developed to conduct proof-of-concept demonstrations and to perform experiments in a laboratory environment. Specifically, the paper describes three technology areas: (1) manipulator control for sensor placement; (2) automated non-contact inspection to detect and classify flaws; and (3) an operator interface to command the system interactively and receive raw or processed sensor data. Initial findings for the automated and human visual inspection tests are reported

A study on the ethical components of nursing practice (moral distress, ethical sensitivity, ethical decision)

This paper is an applied research in terms of objective and a descriptive research in terms of method. Having prepared the research plan, a questionnaire was designed based on goals and hypotheses of the research and was sent to the statistical universe. Also this paper is a field research in terms of data collection. As regards theoretical bases of the research, library data collection method has been applied. So, the required data has been gathered by referring to the related references, books, libraries and so on. To design a questionnaire and gather the opinions of the statistical universe members, field study method and researcher-made questionnaire have been used. The statistical universe comprises nurses and head of ICU and head nurses of Najmieh Hospital in Tehran. The respondents were selected by random sampling method. Also to estimate sample size, Morgan table was applied. The statistical universe consists of 65 members and according to the table, 56 questionnaires were determined for the research. So 60 questionnaires were sent and 58 ones were returned. Face and content validity of the research tool were approved by experts. The test reliability was estimated 0.777 by calculating Cronbach's alpha coefficient. In this paper, factor analysis based on partial least squares structural equations method has been applied to analyze more important factors and coefficients, estimate independent variables coefficients and even determine effectiveness of each independent variable on each other and determine appropriateness of the questions and their coefficients in explaining the related index. The main result of this paper presents a proper model for the relation of effective variables on nurse performance by using regression model. © IDOSI Publications, 2014

Experimental Study on the Compressive Membrane Action in Profiled Steel Sheet Dry Board (PSSDB) Floor System

This paper describes the experimental work conducted at Universiti Kebangsaan Malaysia to examine the capability of the profiled steel sheet dry board (PSSDB) system to develop the compressive membrane action (CMA) in the floor. The development of the CMA inside the floor is strictly associated with the horizontal movement of the slab end under the vertical loading. Therefore, the simply supported PSSDB floor was tested under vertical uniformly distributed load. Study of results revealed that the recorded horizontal movement at the roller support of the slab is 0.81 mm in the pin- roller supported case. This proves that the PSSDB floor has the potential to develop the CMA under the pin-pin support condition

The study of teachers’ motives and usage of social networks

Background and Objectives: Users enter social networks with different motives and their participation in social networks is also different from each other. Having different goals and motives, teachers as users of social networks choose various ways to participate in these networks. So, laying emphasis on the role of motivation in the ways teachers use social networks, the present study aims at identifying teachers’ motivation and the ways they use social networks. The specific objectives of this research are: 1. determining how virtual social networks are used by teachers who are actively using them. 2. Identifying the feedback of teachers in virtual social networks.  Methods: The present research is done using qualitative research approach. The field of this research includes groups and forums of Iranian teachers’ social networks. In this research, 30 teachers who were active in social networks participated among whom 14 teachers were male and 16 teachers were female. All of these participants were managers of virtual channels and Various supergroups in social networks. They were selected using the logic of purposeful sampling and criterion-based method.  The selection criterion was the record or history of the group or channel, the number of the followers and the number of the visitors. Also, the teachers who were selected for the interview in addition to this criterion, were selected in the field of e- content generation in virtual social networks by the Roshd center site as an active content generator. Every interviewee mentioned their views in answer to the interview questions for 40 to 45 minutes. To analyze data, the theme analysis method was used. In this method, first the concepts and codes are extracted from the interview text and then the status of each theme from the type of inclusive, organizing, and basic is determined in the network of themes. In this research, in order to perform this process, the following steps were taken: 1. Frist, with the frequent screening and active reading of the data, the search for the meaning and discovery of patterns began by using  note-taking and punctuating the data (familiarity with the data). 2. After reading the data, the codes and concepts introducing the data were established (generating basic codes). 3. The identified codes were organized and transferred to certain themes (generating themes). 4. At this stage, the themes were named and reviewed as needed 5. The network of themes were generated to identify the basic, organizing and inclusive themes and the final report of the data was set.  Findings: The findings showed that teachers benefit from social networks for personal purposes such as entertainment, access to the news and communication with friends, and for occupational purposes, such as professional development and interaction with colleagues. The teachers’ motives affect how they provide feedback and how they participate in the social networks. Teachers show various feedbacks and participation in the social media which can be classified into six levels of reasonable diffusing, liking, controlling, counselling, criticizing, and commenting. Conclusion: Levels of teachers’ participation in the social networks in terms of their professional development and occupational learning is of significance from the perspective that the more the participation of the teachers in social networks can be organized by using specific projects and programs, so that they can move away from weak interactions, such as diffusing, liking, and controlling towards counselling, criticizing, and reasoning, they can be more profoundly involved with their own occupational themes in the social networks and can benefit from any time, any place, and interactive potentials of this environment for their own professional development.    ===================================================================================== COPYRIGHTS  ©2021 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.  ====================================================================================

Evaluation of a Cluster-Randomized Controlled Trial of a Package of Community-Based Maternal and Newborn Interventions in Mirzapur, Bangladesh

To evaluate a delivery strategy for newborn interventions in rural Bangladesh.A cluster-randomized controlled trial was conducted in Mirzapur, Bangladesh. Twelve unions were randomized to intervention or comparison arm. All women of reproductive age were eligible to participate. In the intervention arm, community health workers identified pregnant women; made two antenatal home visits to promote birth and newborn care preparedness; made four postnatal home visits to negotiate preventive care practices and to assess newborns for illness; and referred sick neonates to a hospital and facilitated compliance. Primary outcome measures were antenatal and immediate newborn care behaviours, knowledge of danger signs, care seeking for neonatal complications, and neonatal mortality.A total of 4616 and 5241 live births were recorded from 9987 and 11153 participants in the intervention and comparison arm, respectively. High coverage of antenatal (91% visited twice) and postnatal (69% visited on days 0 or 1) home visitations was achieved. Indicators of care practices and knowledge of maternal and neonatal danger signs improved. Adjusted mortality hazard ratio in the intervention arm, compared to the comparison arm, was 1.02 (95% CI: 0.80-1.30) at baseline and 0.87 (95% CI: 0.68-1.12) at endline. Primary causes of death were birth asphyxia (49%) and prematurity (26%). No adverse events associated with interventions were reported.Lack of evidence for mortality impact despite high program coverage and quality assurance of implementation, and improvements in targeted newborn care practices suggests the intervention did not adequately address risk factors for mortality. The level and cause-structure of neonatal mortality in the local population must be considered in developing interventions. Programs must ensure skilled care during childbirth, including management of birth asphyxia and prematurity, and curative postnatal care during the first two days of life, in addition to essential newborn care and infection prevention and management.Clinicaltrials.gov NCT00198627