A Low-Complexity Precoding Scheme for the Downlink of Multi-Cell Multi-User MIMO AF System

Because of its simplicity, amplify-and-forward (AF) is one of the most popular cooperative relaying technique. Relays are used in cooperative communication to improve reliability, coverage or spectral efficiency of cell-edge users. However, relays tend to increase the interferences seen by users of adjacent cells, particularly by the cell-edge users, when used in multi-cell systems. In this paper, we propose a low-complexity precoding scheme to mitigate the effect of other-cell interference (OCI) in cooperative communication. The scheme is designed by taking into account the interference plus noise covariance matrix of each user for mitigating the interference at each receiver by means of precoding at the relay node. Simulation results show the effectiveness of the proposed scheme, both in terms of sum-rate and computational complexity, when compared to other existing OCI-aware precoding algorithms for AF

A User Scheduling Scheme for Reducing Electromagnetic (EM) Emission in the Uplink of Mobile Communication Systems

The ubiquity and convergence of wireless communication services have contributed to an unprecedented popularity of mobile communications. Given that wireless communication systems operate on radiofrequency waves, the electromagnetic (EM) radiation exposure they generate is also unprecedented and, hence, this could have adverse health effects on both humans and animals according to the World Health Organization. In this paper, we propose a user scheduling/power allocation scheme to minimize the EM exposure of users subject to transmitting a target number of bits. Our user scheduling method is based on assigning priority levels to each user and the user with the lowest priority level is scheduled for transmission. Power allocation, on the other hand, is based on the water-filling approach over time by using the past channel gains of a user to compute its water level. Simulation results show that our proposed scheme performs much better than a spectral efficiency based scheme but has a higher EM emission in comparison with a non-practical ideal scheme

A survey and tutorial of electromagnetic radiation and reduction in mobile communication systems

This paper provides a survey and tutorial of electromagnetic (EM) radiation exposure and reduction in mobile communication systems. EM radiation exposure has received a fair share of interest in the literature; however, this work is one of the first to compile the most interesting results and ideas related to EM exposure in mobile communication systems and present possible ways of reducing it. We provide a comprehensive survey of existing literature and also offer a tutorial on the dosimetry, metrics, international projects as well as guidelines and limits on the exposure from EM radiation in mobile communication systems. Based on this survey and given that EM radiation exposure is closely linked with specific absorption rate (SAR) and transmit power usage, we propose possible techniques for reducing EM radiation exposure in mobile communication systems by exploring known concepts related to SAR and transmit power reduction in mobile systems. Thus, this paper serves as an introductory guide to EM radiation exposure in mobile communication systems and provides insights toward the design of future low-EM exposure mobile communication networks

Expanding cellular coverage via cell-edge deployment in heterogeneous networks: spectral efficiency and backhaul power consumption perspectives

Heterogeneous small-cell networks (HetNets) are considered to be a standard part of future mobile networks where operator/consumer deployed small-cells, such as femtocells, relays, and distributed antennas (DAs), complement the existing macrocell infrastructure. This article proposes the need-oriented deployment of smallcells and device-to-device (D2D) communication around the edge of the macrocell such that the small-cell base stations (SBSs) and D2D communication serve the cell-edge mobile users, thereby expanding the network coverage and capacity. In this context, we present competitive network configurations, namely, femto-on-edge, DA-onedge, relay-on-edge, and D2D-communication on- edge, where femto base stations, DA elements, relay base stations, and D2D communication, respectively, are deployed around the edge of the macrocell. The proposed deployments ensure performance gains in the network in terms of spectral efficiency and power consumption by facilitating the cell-edge mobile users with small-cells and D2D communication. In order to calibrate the impact of power consumption on system performance and network topology, this article discusses the detailed breakdown of the end-to-end power consumption, which includes backhaul, access, and aggregation network power consumptions. Several comparative simulation results quantify the improvements in spectral efficiency and power consumption of the D2D-communication-onedge configuration to establish a greener network over the other competitive configurations

Electromagnetic emission-aware schedulers for the uplink of OFDM wireless communication systems

The popularity and convergence of wireless communications have resulted in continuous network upgrades in order to support the increasing demand for bandwidth. However, given that wireless communication systems operate on radiofrequency waves, the health effects of electromagnetic emission from these systems are increasingly becoming a concern due to the ubiquity of mobile communication devices. In order to address these concerns, we propose two schemes (offline and online) for minimizing the EM emission of users in the uplink of OFDM systems, while maintaining an acceptable quality of service. We formulate our offline EM reduction scheme as a convex optimization problem and solve it through water-filling. This is based on the assumption that the long-term channel state information of all the users is known. Given that, in practice, long-term channel state information of all the users cannot always be available, we propose our online EM emission reduction scheme, which is based on minimizing the instantaneous transmit energy per bit of each user. Simulation results show that both our proposed schemes significantly minimize the EM emission when compared to the benchmark classic greedy spectral efficiency based scheme and an energy efficiency based scheme. Furthermore, our offline scheme proves to be very robust against channel prediction errors

Spectral Efficiency Improvements in HetNets by Exploiting Device-to-Device Communications

Next generation cellular networks require huge capacity, ubiquitous coverage and maximum energy efficiency. In order to meet these targets, Device-to-device (D2D) communication is being considered for future heterogeneous networks (HetNets). In this paper, we consider a three tier hierarchical HetNet by exploiting D2D communication in traditional HetNet. D2D communication is deployed within the HetNet where closely located mobile users are engaged in direct communication without routing the traffic through cellular access network. The proposed configuration mandates to reduce the interference offered by the resultant HetNet by reducing the transmitter-receiver distance and ensuring that the mobile users are transmitting with adaptive power subject to maintaining their desired link quality. In this context, we analyzed and compared the spectral efficiency improvements in hierarchical HetNet against traditional HetNet. Simulation results show that D2D communication offers much higher spectral efficiency as compared to traditional HetNet

Effect of Auditor Ethics, Knowledge and Dysfunctional Behavior Audit Office of the Quality of Public Accountants in Makassar

Cases of violation of the Public Accountants Professional Standards at Drs. Mitrawinata and colleagues, due to unfavorable auditor ethics where Drs. Peter Partner Winatadari as Public Accountant (AP) violated the Public Accountants Professional Standards (SPAP) relating to the audit that the general audit assignment restrictions on financial statements Muzatek Jaya. Associated with good audit quality, there are several things that affect them auditor ethics, knowledge and dysfunctional behavior. This study aims to determine the effect of auditor ethics, knowledge and dysfunctional behavior on audit quality either simultaneously or partially on public accounting firm in Makassar. The sampling technique using saturated sampling technique, in order to obtain a sample of 37 respondents. Methods of data analysis using multiple linear regression techniques, test F and test t. These results indicate that the auditor ethics, knowledge and dysfunctional behavior simultaneously significant positive effect on audit quality in the public accounting firm in Makassar. Partially ethics of auditors and knowledge of significant positive effect on audit quality, but not for the dysfunctional behavior that significant negative effect on audit quality. The level of contribution influence auditor ethics, knowledge and dysfunctional behavior on audit quality is high. This is caused by some respondents to variable auditor ethics, knowledge and quality of the audit is still no answer neutral and do not agree, while the dysfunctional behavior variables still exist some respondents who answered disagree and strongly disagree

A Scoping Review of Research Ethics and Practices in Library and Information Science in Scopus and Library and Information Science Source Databases

Introduction and Background: Library and information science scholars are partially aware of the research ethics regarding data falsification, fabrication, data cooking, gifted authorship, neglected authorship, and other factors. Such activities are not only unethical but may equally cause harm to the academic community and society. Purpose: This paper aims to identify the gaps in studies focusing on research ethics and practices in Library and Information Science in the Scopus and Library and Information Science Source Databases. The review seeks to respond to research questions such as what is the scope of articles focusing on research ethics and practices between 2011 and 2021; what are the features of articles focusing on research ethics and practices in the Scopus and LISS domain; to what extent is the African research on ethics and practices and LISS reflected in the domain; and what are the implications of studies focusing on research ethics as reported in the identified literature? Methodology: Databases searched include the Scopus and Library and Information Science Source for articles published between 2011 and 2021. Advanced search strategies are used as well as thematic analysis. Result: Out of 190 documents identified from the databases, 70 were eligible for review while 13 were included in the scoping review. The majority of the articles focusing on research ethics and practices were published between 2016 and 2021. The year 2021 witnessed the highest number of publications, while the lowest was in 2014. The majority of studies published in the LIS domain emerged from developed countries. However, few were published by African scholars in Scopus and LISS focusing on research ethics and practices. Implications: This paper has implications for LIS researchers and policymakers. Practical implications include the control and reduction of data falsifications, data cooking, and unethical research practices among LIS researchers. Implications for efficient knowledge management for sustainable development are also prominent in this paper. Conclusions: Given that limited articles focus on the subject identified in the domain, African scholars need to contribute immensely towards literature addressing research ethics. They also need to engage the researchers, information managers, and policymakers to empower librarians with knowledge of how to manage scholarly publications in academic libraries

Comparison of the durations and complications of spinal anaesthesia between unilateral spinal anaesthesia and bilateral spinal anaesthesia for unilateral lower limb surgery

Despite the advantages of spinal anaesthesia when compared to general anaesthesia, it is associated with complications such as hypotension, bradycardia, shivering and nausea. Our study is set to compare the durations and complications between unilateral and bilateral spinal anaesthesia in patients undergoing unilateral lower limb surgeries. Method: Sixty four (64) American Society of Anesthesiology (ASA) 1 and 2 patients that were randomly assigned to two groups. Group U which is the unilateral spinal anaesthesia and group B which is the conventional bilateral spinal anaesthesia group to receive 2ml of 0.5% heavy bupivacaine plus 1ml of distilled water and 3ml of 0.5% heavy bupivacaine only respectively. The group U patients who had the procedure in the lateral decubitus position remained in that position for 20 minutes, while those in group B had the spinal injection in sitting position and immediately took the supine position after the injection. Results: The 64 adult patients who were randomly allocated into two groups with 32 patients each successfully had their surgeries done under the chosen technique. The mean duration of spinal anaesthesia was found to be 64±23.29 minutes and 100± 37.08 minutes in the group U and B respectively (p=0.001). There was no statistical differences in the general overall complications when the two groups were compared (p=0.03), however, on individual bases unilateral spinal anaesthesia has less complications compared to bilateral spinal anaesthesia for unilateral lower limb surgeries. Conclusion: The study showed that unilateral spinal anaesthesia with 2 ml of 0.5% bupivacaine had shorter duration of spinal anaesthesia with less complications compared to bilateral spinal anaesthesia for unilateral lower limb surgeries