Action Research: A Spiral Inquiry for Valid and Useful Knowledge

This article discusses methodological and philosophical issues linked to action research. The concepts of subjectivity and objectivity—potential sources of bias that mislead researchers in dealing with these concepts—and how to cope with them are discussed. Controversial issues of truth in positivism, postpositivism, and other schools of philosophy are considered. Finally, the article touches on validity criteria, validity types, and how to grapple with validity in action research.Cet article porte sur des enjeux méthodologiques et philosophiques liés à la recherche-action. On y discute les concepts de subjectivité et d’objectivité, sources potentielles de préjugés qui ont induit en erreur les chercheurs, et la façon de leur faire front. Des questions controversées touchant la vérité dans le positivisme, le postpositivisme et d’autres écoles de philosophie sont également étudiées. Finalement, l’article évoque les critères de validité, les types de validité et la façon d’aborder la validité en recherche-action

Impacts of Channel Switching Overhead on the Performance of Multicast in Wireless Mesh Networks

Wireless mesh networks (WMNs) have emerged as a promising technology for next generation wireless networking. A WMN extends network coverage using wireless mesh routers that communicate with each other via multi-hop wireless communications. One technique to increase the network capacity of WMNs is to use routers equipped with multiple radios capable of transmitting and receiving on multiple channels. In a Multi-Channel Multi-Radio wireless mesh network (MCMR WMN), nodes are capable of transmitting and receiving data simultaneously through different radios and at least theoretically doubling the average throughput. On the other hand, the use of multi-radio and multi-channel technology in many cases requires routers to switch channels for each transmission and/or reception. Channel switching incurs additional costs and delay. In this thesis, we present a simulation-based study of the impacts of channel switching overheads on the performance of multicast in MCMR WMNs. We study how channel switching overheads affect the performance metrics such as packet delivery ratio, throughput, end-to-end delay, and delay jitter of a multicast session. In particular, we examine: 1. the performance of multicast in MCMR WMNs with three orthogonal channels versus eleven overlapping channels defined in IEEE 802.11b. 2. the performance of the Minimum-interference Multi-channel Multi-radio Multicast (M4) algorithm with and without channel switching. 3. the performance of the Multi-Channel Minimum Number of Transmissions (MCMNT) algorithm (which does not do channel switching) in comparison with the M4 algorithm (which performs channel switching)

RF Energy Harvesting System and Circuits for Charging of Wireless Devices Using Spectrum Sensing

Recently, lots of works have been done on the optimal power management of wireless devices. This leads to the main idea of ambient energy harvesting. Among various energy harvesting approaches, one is to use radio waves existing in the ambient environment for battery charging, called RF energy harvesting. In this chapter, in order to improve the RF energy harvesting performance, we utilize spectrum sensing to allow the wireless devices to select the frequency band with maximum power that exceeds a predefined threshold to charge the device (this power threshold can be determined according to battery type and its required charging power) and the device can use this power for battery charging. Also, a novel voltage multiplier circuit is proposed. By means of simulations and experimental tests, it can be seen that after detection of our desired 1 mW RF signal, system output power is about 532μ W and 450μ W in simulation and practical situations respectively

Researchers\u27 Scientific performance in ResearchGate: The Case of a Technology University

With the advancement of technology and changes made in the scientific communication model, changes have been made in scientific evaluation methods. New technologies offer indicators that measure all the actions and interactions of scientists in the digital environment and create new aspects of scientific communication. This work has some purposes; first, mapping profile of scientific activities of faculty members of Sharif University of Technology (SUT) in “ResearchGate” (RG), second, intend to test the correlation h-index between the RG and Web of Science (WoS) and Scopus and Google Scholar (GS). Third, investigate SUT faculty members’ top h cited research RG in WoS, Scopus, and GS. Fourth, investigate Altmetric score of SUT faculty members’ top h cited research RG with Altmetric Explorer (AE). For this purpose, the SUT faculty members were searched in RG. Information was noted for those who were members in RG. Then, all their h index and the number of citations of top h cited research were extracted from WoS, Scopus and GS. Altmetric scores of Top h cited research of SUT faculty members was obtained by using AE. The degree of correlation between RG h index and WoS h index was higher than the h index of other citation databases. Also, the results indicate that there are errors in the calculation of the Almetric score by AE. Only 3% of the top h cited research of SUT faculty members had Altmetric score. While 95.72% of them had been read at least once in Mendeley and 78.7% of them had been cited in Mendeley

Numerical radius inequalities for Hilbert C∗C^{*}-modules

summary:We present a new method for studying the numerical radius of bounded operators on Hilbert $C^*$-modules. Our method enables us to obtain some new results and generalize some known theorems for bounded operators on Hilbert spaces to bounded adjointable operators on Hilbert $C^*$-module spaces

Identifying components of international social cataloging sites to present criteria for native model

Abstract The purpose of this article is to provide criteria for native model of social cataloging sites based on the world\u27s most visited, popular social cataloging site\u27s components. Social cataloging sites are a kind of web-based social media that allows users to interact. This is an applied research and the research method is library and descriptive scrolling. First, by reviewing the scientific literature and resources, a list consists of 14 criteria which included 73 extracted components, then finalized in Delphi and evaluated was used. The community studied also includes three social cataloging sites, which have the most visitors on the Alexa ranking. The results of this study showed that the total score for the fourteen criteria considered in this study was173/31points. The average of observance of criteria in all social cataloging sites(58.10%)is above the average and is in a favorable situation. Goodreads ranked first among the sites listed in the study list with 46 points(63.01%).after that LT is ranked second by the score of45points(61.64%) and anobi reached third rank with36.25points(49.65). All of the components examined in this study are important and the search facilities with an average of 9.70have the highest importance and error messages with an average of9.24are ranked second

An experimental study on condensation heat transfer characteristics of R-600a in tubes with coiled wire inserts

In this experimental research, condensation heat transfer enhancement of R-600a as a consequence of used spring inserts inside a horizontal condenser is studied. The condenser was a copper tube with the internal diameter, wall thickness, and length of 8.1, 0.71, and 1000 mm, respectively. Five coiled wires with various coil pitches of 10, 20 and 30 mm, and various wire diameters of 0.5, 1 and 1.5 mm were used inside the test pipe. Tests were conducted at vapor qualities within the range of 0.03-0.79 and mass velocities between 115-365 kg/m2s. Results indicated that coiled wires are advantageous instruments in heat transfer improvement of the condenser. In this regard, the coiled wire with the wire diameter of 1.5 mm and coil pitch of 10 mm showed the best performance among all inserts by the heat transfer coefficient increased up to 107% over the smooth tube. It was also observed that the use of springs affects the transition of flow pattern from annular to intermittent, and the annular regime was observable at a lower vapor quality in comparison to the smooth tube. Finally, a new correlation is developed to predict the condensation heat transfer coefficients of R-600a in coiled wire inserted tubes

Formulation and Evaluation of Lorazepam Orally Disintegrating Tablet

Introduction: oral dosage forms are the safest, the most convenient and the most economical method of drug delivery system in the pharmaceutical industry but, in geriatric and pediatric patients who have swallowing difficulty and in the emergency situations, we need the fastest therapeutic effects on conventional oral drug delivery because  of time issue. To troubleshoot? such problems a new dosage form known as orally disintegrating tablets (ODT) can be useful and more effective. Lorazepam is  a benzodiazepine drug that stimulates GABA receptor and is used in the prevention of panic attack, management of anxiety disorders, treatment of status epilepticus andetc. Based on these details, ODT form of Lorazepam can be helpful for geriatric and pediatric patients and also handling emergency situations. Methods and Results: In this study, various formulations were designed and prepared by using direct compression method. All of our formulations contained 2 mg of Lorazepam as API. We used 3 differences bulking agents (mannitol, lactose, avicel) and the percentages of disintegrating agent (5%, 10%, 15% of crosscarmelose).then, for examining our formulations and choosing the best formulation we carried out or conducted physicochemical tests like flowability of powder, tablet appearance, thickness, uniformity of weight, hardness, friability and disintegration time. Finally, one of these formulations (lactose as bulking agent and 10% crosscarmelose as disintegrating agent) which showed optimum physicochemical properties was selected for further studies. Conclusions:  regarding our study and literatures, we attempted to evaluate a novel formulation of Lorazepam ODT. physicochemical test results showed this formulation  ideal for developing new dosage forms of Lorazepam for resolving some of the patient's problems

Predictors of Life Skills Level of Students in Zahedan University of Medical Sciences in Southeast of Iran

Background and aims: Life skills involve a big class of socio-psychological and interpersonal skills which help a person to take conscious decisions, communicate effectively and improve self-management skills. Preparing a plan for all the above mentioned programs, need awareness about life skills level of different groups such as students in universities. Present study was aimed to reveal the predictors of life skills level of Students in Zahedan University of Medical Sciences in southeast of Iran. Methods: This cross-sectional study carried out on 380 medical students of Zahedan in 2015. The subjects were selected using stratified random sampling method. The data were collected using reliable Life Skill Dimensions Score questionnaire. The data were analyzed in Stata.12 software using ANOVA, Independent t-test and multiple linear regression with Hosmer-Lemshow method. Results: The mean of total score regarding life skills score was 280.8±45.8. The linear regression analysis indicated that gender (β=11.15, 95 CI: 5.03-17.27), socioeconomic status (β=6.78, 95 CI: 1.76-11.8) and average grades (β=15.3, 95 CI: 9.11-21.49) were associated with life skills score. However, the life skills score was not associated with the age, semester, residential area, smoking, marital status and school of education (P>0.05). Conclusion: The level of life skills scores of medical students in southeast of Iran is low in all dimensions especially in communication skills. Thus, promoting life skills in university students is too important. However, the life skills training programs should be implemented with respect to socioeconomic status, gender and average grade and male students with low socioeconomic status and average have priority