مطالب

The study of path loss propagation is of high importance in telecommunication, for optimizing the efficiency of wireless communication networks. In this paper, four path loss propagation models; free space path loss (FSPL) model, Okumura model, Okumura-Hata model, and COST 231-Hata model were compared. The models were compared using measurement data from Choba, Port Harcourt, Nigeria. The data is gotten from a 4G walk test using two mobile applications. The first mobile application Network, Signal Info (version 5.68.07), was used to acquire the received signal strength in and the distance between the BTS antenna and the mobile antenna. While the second mobile application, G-NetTrack Lite (version 14.8), was used to map out the track path followed during the test. Choba, the study area, is a coastal suburban area with map coordinates 4.8941° N, 6.9263° E. The measured distance range was from 0.09 km to 0.45 km, and a path loss range of 69dB to 81dB. While the BTS and mobile antenna heights were 32 m and 1m respectively, with a carrier frequency of 800MHz. BTS transmission power of 23 dBm was assumed, based on 3GPP eNodeB recommendations. A graph comparison of the studied models showed that Okumura-Hata model and COST 231-Hata model had the closest predictions to the measured path loss. The need for better path loss models for 4G and 5G propagations was observed

With the corona epidemic, virtual education has received the attention of the educational system more than before. Taking advantage of virtual education regardless of its basic principles and possible challenges will cause obstacles and problems in the implementation, effectiveness, and practical use of its capacities. The aim of the current research was to study the phenomenological challenges of virtual education and evaluation in primary schools from the perspective of teachers and parents. The research method was qualitative and phenomenological. The participants were 34 teachers and parents of elementary school students of Gonabad city (17 persons in each group), who were selected using the snowball sampling method. To collect the data, a semi-structured interview was used. Based on theoretical saturation, 34 interviews were conducted. To analyze the data, the seven-step Claysey method was used. After removing similar items and formulating concepts, the data analysis process led to the extraction of 48 sub-concepts. Sub-concepts were categorized under 4 main categories: 1) cultural and social challenges, 2) technical and infrastructure challenges, 3) educational challenges, and 4) ethical challenges. The results of the present study can be used to solve possible challenges and increase its effectiveness while using the capabilities of virtual education.

While various aspects of Group Dynamic Assessment (GDA) have been explored in previous studies, cumulative GDA in distance education is an under-researched area. This study aims to examine the effect of on teaching of cumulative GDA in English as a Foreign Language (EFL) settings with a focus on discourse markers. To this end, a mixed-methods design was adopted with speaking tasks of First Certificate in English (FCE) test and interviews used as the main instruments for collecting data in the quantitative and qualitative phases of this study. A total of 64 homogenized female EFL learners were randomly divided into experimental and control groups. Cumulative GDA instruction of discourse markers in the experimental group was conducted by a teacher well-trained in intervention workshops. The analysis of the data based on T-test and analysis of covariance (ANCOVA) showed a positive effect of GDA on the test group. In the qualitative phase of the study, interviews were used as the tool to reveal the attitudes of ten participants in the experimental group who opted to attend interview sessions. The content analysis of the interview results revealed that they had varied attitudes towards online cumulative GDA, and dominantly favoured this teaching approach in distance learning. The results highlight the importance of Assessment for learning (AfL) over Assessment of Learning (AoL) in distance education. Findings have implications for policy, practice and research.

Pluralists believe in the occurrence of numerically distinct spatiotemporally coincident objects. They argue that there are coincident objects that share all physical and spatiotemporal properties and relations; nevertheless, they differ in terms of modal and some other profiles. Appealing to the grounding problem according to which nothing can ground the modal differences between coincident objects, monists reject the occurrence of coincident objects. In the first part of this paper, I attempt to show that the dispute between monists and pluralists cannot be settled based upon the grounding problem tout court. I argue that the grounding problem or a very similar problem is a challenge for all monists and pluralists alike if they are ontologically committed to the existence of composite objects as independent entities. In the final part, adopting the Aristotelian account of essence, I propose a solution that enables pluralists to plausibly ground modal differences between coincident objects.  

Purpose: The purpose of this study was to provide a model for managing volunteer forces in the Imam Khomeini Relief Foundation (grounded theory).  Methodology: In the present study, the grounded theory method has been used. The statistical population consisted of experts and professors who were knowledgeable in the field of management and could provide valuable information to the researcher. The research sample was selected through chain sampling method (snowball). Data were collected through 15 semi-structured interviews with professors and experts selected by purposive sampling. The data were analyzed through three stages of open, axial and selective coding.  Findings: A model including 5 dimensions, 13 main categories and 41 sub-categories was presented and validated by members' check. Categories are as following: Causal conditions (Having monotheistic faith, having organizational faith, believing in the philosophy of the organization, paying attention to both material and spiritual aspects, having faith and commitment, belief in Velayat-e-Faqih, adhering to revolutionary values, paying attention to Islamic values, paying attention to the value of human relations). Underlying conditions (Respect for members, strengthening self-confidence in the group, strengthening self-confidence in the group, cooperation and team spirit, forming an effective team, division of labor among members, talking to employees, verbal communication, respect for the feelings of others, understanding the position of others). Interfering factors (Determining a clear mission and goal, having a vision, comprehensive knowledge of the organization, problem analysis, quality decision making, prudence and rational decision making, understanding the rules of the organization, the ability to communicate multilaterally, the ability to adjust the rules). Strategies (Develop dynamic methods of recruitment, synergy, training of subordinates, keeping employees up to date, involvement in decisions). Consequences (Retaining the old volunteer forces, attracting new volunteer forces, improving the level of organizational culture, creating a suitable work environment for volunteers, creating a favorable atmosphere in the organization, growing the participatory spirit, growing synergy, growing solidarity). Also, a comprehensive and inclusive model that covers all the contextual, environmental, technical and informational aspects related to the recruitment of volunteers in the Imam Khomeini Relief Foundation was found as a central category. Conclusion: It is necessary to pay attention to the volunteer forces in the Imam Khomeini Relief Foundation, which requires paying attention to issues such as respect for members, team spirit, training subordinates, strengthening organizational culture, creating a favorable organizational atmosphere.