Cooperative Techniques Research Articles

Ultra‐wideband technology: Prospective solution for 5G ultra‐small cell networks

SummaryExhaustive research is being done to establish the technologies and standards of the fifth generation (5G) of wireless communication systems. Some of the most challenging requirements of 5G systems are to increase the spectral efficiency and the capacity by a factor of 10 and 1,000, respectively. New technologies must offer an adequate framework for the 5G uses cases, which will enable higher capacities and the flexibility to adapt to dynamic scenarios. To cope with these challenging demands, a compelling approach is to exploit the current radio service bands by means of spectrum sharing and cooperation techniques, which alleviate the bandwidth requirements. In addition, advanced modulation schemes have a fundamental role in ensuring the best usage of the spectrum available in band‐limited systems. In this manuscript, we present the ultra‐wideband (UWB) technology as a prospective solution for 5G picocells and femtocells. Its main feature is its capability to operate simultaneously, without introducing interference, with current radio services on an unlicensed basis. We report experimental results reaching data rates up to 35 Gbit/s using the multiband approach of carrierless amplitude phase (MB‐CAP) modulation. To validate the versatility of the proposed system, our experimental tests were performed under the UWB regulations defined by the United States' Federal Communications Commission (FCC), the European Electronic Communications Committee (ECC), and the Russian State Committee for Radio Frequencies (SCRF). The regulations chosen provide diversity enough to demonstrate the capacity of MB‐CAP modulation to comply with worldwide regulations.

Energy efficient resource optimization in cooperative Internet of Things networks

Internet of Things (IoT) network has been envisioned as a promising technology to satisfy the exponentially growing mobile traffic requirements. Cooperative communication technique has been proposed to significantly improve energy efficiency in resource-constrained network. In this paper, we focus on resource allocation optimization and optimal relay selection to maximize the energy efficiency of the IoT networks. Using different cooperative techniques, we have studied the resource optimization problems for a single-hop network topology and a generic cooperative multi-hop network topology. Based on dual optimization framework, we formulate an optimal algorithm to reduce the total transmit power through channel allocations and optimal relay selection for each source to destination communication link while satisfying the quality of service (QoS) requirements. We derive the closed-form expressions for the outage probabilities of the cooperative relaying protocols to improve data transmission and propose an energy efficient power routing algorithm to enhance energy efficiency. Simulation results show an effective performance gain of the proposed algorithm as compared with other existing power saving algorithms in terms of system throughput and energy efficiency.

Comparative effects of self-assessment, peer-assessment, and teacher assessment on EFL learners’ writing performance

Self-assessment and peer-assessment, as two alternative assessment procedures, have appealed to researchers in recent years and motivated L2 researchers to examine these two techniques. However, most of the studies have used them for summative purposes, and the formative dimension these two methods can have for learning has been neglected. This study was an attempt to find how they contributed to learning gains. To that end, sixty Iranian male and female intermediate language learners at a language institute were randomly assigned into three treatment conditions: Selfassessment and peer-assessment as experimental groups and teacher assessment as a control group. A language proficiency test was used to homogenize language learners, and a posttest was administered to measure the amount of gain language learners achieved after treatment sessions. We analyzed the test data using descriptive and inferential statistics as implemented in SPSS, a general-purpose computer program for data analysis. Results from a one-way analysis of variance showed statistically significant differences between the score means of three treatment groups. Post-hoc analyses revealed that language learners in the peer-assessment group outperformed those in the other two groups. The findings suggest that peer-assessment as a cooperative technique can be used in language classes to help students improve their writing abilities.

Resource Allocation for Cooperative Transmission in Optical Wireless Cellular Networks With Illumination Requirements

Visible light communication (VLC) often suffers from line-of-sight path blockages and high levels of inter-cell interference. Thus, the analysis and design of cooperation techniques become crucial to address these key impairments. This paper studies the performance of different resource allocation schemes that are suitable for multi-cell cooperative transmission when tri- and tetra-chromatic light-emitting diodes (LEDs) and optical orthogonal frequency-division multiple access are utilized. Firstly, guidelines are derived for maintaining the same spatial distribution of the signal-to-interference-plus-noise ratio (SINR) in every sector of the multi-cell environment in case of stand-alone (non-cooperative) and cooperative transmission. Secondly, the possible resource allocation configurations for both stand-alone and cooperative transmission modes are identified for different LED types and available orthogonal resources (i.e., frequency sub-bands per color and sectors per cell). Finally, the data rate gain of the multiple resource allocation configurations are also analyzed, while verifying the illumination constraints. The obtained results confirm that the proper design of cooperative transmission configurations will be of paramount importance to provide reliable wireless link in ultra-dense VLC deployments.

Joint Long-Term Energy Efficiency Optimization in C-RAN With Hybrid Energy Supply

In energy harvesting cloud radio access network (C-RAN), energy cooperation technique can be utilized to improve system performance with the recent advances in smart grid. This paper investigates a long-term energy efficiency (EE) optimization problem in hybrid energy supplied C-RAN. In order to maximize the long-term utility and still maintain the network stability, a stochastic optimization problem is formulated. Particularly, both of the instantaneous quality of service (QoS) requirements and time-averaged limits are considered in the problem. By introducing Lyapunov framework together with the drift-plus-penalty method, we propose an EE-based power allocation and energy cooperation (EE-PAEC) scheme by jointly optimizing both of the sustainable energy and the grid power. The power allocation scheme contributes to optimal long-term EE with the deterministic upper bound of the data queue backlog, without requiring any prior knowledge of the dynamic system. Furthermore, theoretical analysis and simulation results demonstrate the performance advantage of energy cooperation, and show that the proposed scheme can provide a balanced trade-off between utility and stability.

Wireless Network Simplification: The Performance of Routing

This paper explores the network simplification problem for Gaussian full-duplex relay networks with arbitrary topology. Particularly, given an $N$ -relay Gaussian full-duplex network, the network simplification problem seeks to find fundamental guarantees on the capacity of the best subnetwork, among a particular class of subnetworks, as a fraction of the full-network capacity. The focus of this work is the case when the selected subnetwork class is a path from the source to the destination. The main result of the paper shows that for an $N$ -relay Gaussian networks with arbitrary topology, the best route can in the worst case guarantee an approximate fraction $\frac {1}{ \lfloor N/2 \rfloor + 1}$ of the capacity of the full network, independently of the channel coefficients and/or operating SNR. Furthermore, this guarantee is shown to be fundamental, i.e., it is the highest worst-case guarantee that can be provided for routing in relay networks. A key step in the proof of the main result lies in the derivation of a simplification result for antenna selection in MIMO channels that may also be of independent interest. To the best of our knowledge, this is the first result that characterizes the performance of routing in comparison to physical layer cooperation techniques that approximately achieve the network capacity for general wireless network topologies. The results in this paper show that routing can, in the worst case, result in an unbounded gap from the network capacity - or reversely, physical layer cooperation can offer unbounded gains over routing.

Geographic information-based Data Transmission and Cooperative Communication for Vehicular Networks

With the advancements in Vehicular communication technologies in automobile engineering leads to enhancement of modern societies by utilizing Internet based data communication in a vehicular network to effectively avoid accidents and traffic congestions using Multi Input Multi Output (MIMO) cooperative relay technique for enhancing the aspects of performance by reduction of transmission energy consumption by taking the advantage of spatial and temporal diversity gain in a vehicular network as the conventional routing based on topology is merely not suitable over a dynamic vehicular network environment as GPS is used to identify effective route [4].In this paper we propose applications of cooperative communication techniques and their survey for identifying close relationship between forwarding and addressing techniques in a vehicular network and further we compare performance and energy consumption of cooperative techniques with the traditional multi-hop technique over Rayleigh channel using MQAM for optimization.

Geographic information-based Data Transmission and Cooperative Communication for Vehicular Networks

With the advancements in Vehicular communication technologies in automobile engineering leads to enhancement of modern societies by utilizing Internet based data communication in a vehicular network to effectively avoid accidents and traffic congestions using Multi Input Multi Output (MIMO) cooperative relay technique for enhancing the aspects of performance by reduction of transmission energy consumption by taking the advantage of spatial and temporal diversity gain in a vehicular network as the conventional routing based on topology is merely not suitable over a dynamic vehicular network environment as GPS is used to identify effective route [4].In this paper we propose applications of cooperative communication techniques and their survey for identifying close relationship between forwarding and addressing techniques in a vehicular network and further we compare performance and energy consumption of cooperative techniques with the traditional multi-hop technique over Rayleigh channel using MQAM for optimization.

TRANSFER OF MANURE FROM LIVESTOCK FARMS TO CROP FIELDS AS FERTILIZER USING AN ANT INSPIRED APPROACH

Abstract. Intensive livestock production might have a negative environmental impact, by producing large amounts of animal excrements, which, if not properly managed, can contaminate nearby water bodies with nutrient excess. However, if animal manure is exported to distant crop fields, to be used as organic fertilizer, pollution can be mitigated. It is a single-objective optimization problem, in regards to finding the best solution for the logistics process of satisfying nutrient crops needs by means of livestock manure. This paper proposes a dynamic approach to solve the problem, based on a decentralized nature-inspired cooperative technique, inspired by the foraging behavior of ants (AIA). Results provide important insights for policy-makers over the potential of using animal manure as fertilizer for crop fields, while AIA solves the problem effectively, in a fair way to the farmers and well balanced in terms of average transportation distances that need to be covered by each livestock farmer. Our work constitutes the first application of a decentralized AIA to this interesting real-world problem, in a domain where swarm intelligence methods are still under-exploited.

Enhancing Higher-Order Thinking Skills among Home Science Students: The Effect of Cooperative Learning Student Teams- Achievement Divisions (STAD) Module

This study aims to investigate the effectiveness of the cooperative learning module using Student Teams-Achievement Divisions (STAD) techniques in enhancing students' HOTS achievement in the topic of the digestive system and food absorption. A quasi-experimental design was used in this study to gauge the effectiveness of the module. Purposive sampling technique was used to choose the respondents. The study involved 182 students who represented the experimental group and the conventional group. Students were given an intervention by using Home Science STAD Module for five weeks. Descriptive statistics and paired sample t-test were used to determine the effectiveness of the Home Science STAD module on students’ HOTS achievement. The findings show students' understanding increased for the digestive system and food absorption topics. There was a significant difference in students' HOTS achievement between the experimental learning and conventional learning group. The finding shows the students were actively engaged in teaching and learning. Post-test result shows that the students were able to answer the HOTS question correctly and they can deliver clear explanations and justifications compared to the answers in the pre-test. Findings from this study revealed that the Home Science STAD Module was appropriate to serve as a guideline for teachers who apply and integrate HOTS in the teaching process. Further studies can apply cooperative techniques in other educational contexts in promoting HOTS among students. https://doi.org/10.26803/ijlter.19.7.12

Security Aspects in Smart Meters: Analysis and Prevention.

Smart meters are of the basic elements in the so-called Smart Grid. These devices, connected to the Internet, keep bidirectional communication with other devices in the Smart Grid structure to allow remote readings and maintenance. As any other device connected to a network, smart meters become vulnerable to attacks with different purposes, like stealing data or altering readings. Nowadays, it is becoming more and more popular to buy and plug-and-play smart meters, additionally to those installed by the energy providers, to directly monitor the energy consumption at home. This option inherently entails security risks that are under the responsibility of householders. In this paper, we focus on an open solution based on Smartpi 2.0 devices with two purposes. On the one hand, we propose a network configuration and different data flows to exchange data (energy readings) in the home. These flows are designed to support collaborative among the devices in order to prevent external attacks and attempts of corrupting the data. On the other hand, we check the vulnerability by performing two kind of attacks (denial of service and stealing and changing data by using a malware). We conclude that, as expected, these devices are vulnerable to these attacks, but we provide mechanisms to detect both of them and to solve, by applying cooperation techniques.

Transfer of manure as fertilizer from livestock farms to crop fields: The case of Catalonia

Intensive livestock production might have a negative environmental impact, by producing large amounts of animal manure, which, if not properly managed, can contaminate nearby water bodies with nutrient excess. However, if animal manure is exported to nearby crop fields, to be used as organic fertilizer, pollution can be mitigated. It is a single-objective optimization problem, in regards to finding the best solution for the logistics process of satisfying nutrient needs of crops by means of livestock manure. This paper proposes three different approaches to solve the problem: a centralized optimal algorithm (COA), a decentralized nature-inspired cooperative technique, based on the foraging behaviour of ants (AIA), as well as a naive neighbour-based method (NBS), which constitutes the existing practice used today in an ad hoc, uncoordinated manner in Catalonia. Results show that the COA approach is 8.5% more efficient than the AIA. However, the AIA approach is fairer to the farmers and more balanced in terms of average transportation distances that need to be covered by each livestock farmer, while it is 1.07 times more efficient than the NBS. Our work constitutes the first application of a decentralized AIA to this interesting real-world problem, in a domain where swarm intelligence methods are still under-exploited.

TRACING THE EFFECTS OF STUDENTS’ CENTERED TEACHERS’ PEDAGOGICAL APPROACHES ON LEARNERS’ EDUCATIONAL GAINS: CASE OF PUBLIC SECTOR SECONDARY SCHOOLS

Applications of teachers’ pedagogical approaches for learners’ educational gains have been remained one of the educational debates since ago. Teachers transfer chunk of information among students through implementing techniques to strengthen teaching learning process. Relevance of ground-breaking instructional strategies put concrete effect on students’ entire academic success. Present quantitative research was conducted to explore the effect of teachers’ usage of students’ centered teachers’ pedagogical approaches on students’ educational gains. Researchers adopted ex-post-fact research design on sample of 800 respondents; 400 urban and 400 rural students randomly selected from public sector secondary schools of District Kasur Punjab-Province of Pakistan. Data were collected by administering self-constructed questionnaire mode of 5-point Likert type options. Validity of the instrument was confirmed from experts and Cronbach’s Alpha was applied to ensure instrument’s reliability scores; .864. Learners’ educational gains of science and arts students were obtained from gazette of Board of Intermediate and Secondary Education, Lahore. Results of independent sample t-test and regression analysis ascertained that teachers’ centered students’ pedagogical approaches effect 58% on learners’ educational gains whereas brainstorming 43%, inquiry 57%, problem solving 54% and cooperative technique effect 50% on learners’ educational gains. Science teachers were making more use of brainstorming, inquiry, problem solving, and cooperative teaching as compared to arts teachers. Study recommends that Govt. may train heads of the institutions on students’ centered teachers’ pedagogical approaches and bound them to implement with true spirit and vigor through teachers to overcome science and specially arts students’ declining level of educational gains; stakeholders’ cause for concern. Keywords: brainstorming, cooperative teaching, inquiry base, learners’ educational gains, problem solving.

Energy-Efficiency-Based Power Allocation Scheme in Multi-user Single-DF-Relay Cognitive Networks

Due to the enhancement in both spectral efficiency and energy efficiency, cognitive radio (CR) being combined with relay cooperation technique is deemed as a promising way to realize green-broadband communication in the fifth generation (5G) networks. In this paper, for such CR-relay networks operating in underlay mode, when multiple secondary cognitive users (SUs) share a common cognitive relay in decode-and-forward manner to complete their physical transmissions, system power consumption is investigated. For the scenarios where the co-channel interference to primary users and the peak transmit power of SUs and cognitive relay are constrained, the problem of power allocation in CR-relay network is formulated to minimizing sum-system-consumption. Then, based on the principle that power-consumption minimization is equivalent to energy-efficiency maximization, a novel power allocation scheme is proposed. Further numerical simulation is used to verify the optimality of the proposed power allocation scheme.

Holding Complexity: Lessons from Team-Teaching an Interdisciplinary Collegiate Course on Urban Sustainability

Lead instructors discuss the structure, opportunities, and pedagogical challenges of an interdisciplinary team-taught course on urban sustainability involving seven professors from six departments across four of George Washington University’s schools over five years. The teaching team prioritized presenting and exploring diverse perspectives on urban sustainability, seeing a key learning objective of this course in students (1) learning to make links between disciplines; (2) having opportunities to reflect, disagree, share, and develop their own perspectives; and (3) developing a life-long engagement and openness with ideas and learning. This is challenging for many students. To promote student learning and engagement in the class, we utilize active-learning and cooperative discussion techniques, and see these as times that the class reaches “interdisciplinarity”. We employ place-based pedagogical approaches, focusing the class on the case-study (and students’ adopted hometown) of Washington D.C., finding that a “layering” of perspectives on a single city helps students see disciplinary similarities and differences more clearly. For those considering a large-team interdisciplinary course, we stress the importance of a lead instructor for coordination—both conceptually and administratively—and adequate institutional support for this unique and challenging endeavor.

Network Coding Techniques for Primary-Secondary User Cooperation in Cognitive Radio Networks

In this paper, we investigate transmission techniques for a fundamental cooperative cognitive radio network, i.e., a cognitive radio system where a Secondary user may act as relay for messages sent by the Primary user, hence offering performance improvement of Primary user transmissions, while at the same time obtaining more transmission opportunities for its own transmissions. Specifically, we examine the possibility of improving the overall system performance by employing network coding techniques. The objective is to achieve this while affecting Primary user transmissions only positively, namely: 1) avoid network coding operations at the Primary transmitter, hence avoiding increase of its storage requirements and keeping its complexity low, 2) keep the order of packets received by the Primary receiver the same as in the non cooperative case and 3) induce packet service times that are stochastically smaller than the packet service times induced in the non-cooperative case. A network coding algorithm is investigated in terms of achieved throughput region and it is shown to enlarge Secondary user throughput as compared to the case where the Secondary transmitter acts as a simple relay, while leaving the Primary user stability region unaffected. A notable feature of this algorithm is that it operates without knowledge of channel and packet arrival rate statistics. We further present a second network coding algorithm which increases the throughput region of the system under certain conditions on system parameters; however, the latter algorithm requires knowledge of channel and packet arrival rate statistics.

Analysis and comparison of different cooperative cellular networks

SummaryThis paper addresses cochannel interference (CCI) in mobile networks. So enhancements of network performance by decreasing CCI are assessed using four diverse interference reduction techniques. These techniques signify traditional sectored fractional frequency reuse (FFR), sectored FFR with beamforming (BF), relay‐assisted (R‐A) sectored FFR, and R‐A sectored FFR with BF technique. Additionally, each BF cooperative technique applies the vertical BF, three‐dimensional (3D) BF, and horizontal BF. Consequently, sectored FFR with BF contains three cases. These cases indicate sectored FFR applies horizontal BF, sectored FFR deploys vertical BF, and sectored FFR uses 3D BF. Furthermore, there are three different arrangements of applying BF in R‐A sectored FFR with BF. These arrangements signify that relay station (RS) employs BF only, base station (BS) uses BF only, and both RS and BS apply BF. Therefore, each arrangement consists of three different cases according to the applied BF technique. Consequently, nine dissimilar cases are considered. Also, a comparison of all cases in different techniques is introduced to enhance the network performance. Analytical treatments are conducted. As a result, closed‐form expressions (CFEs) for worst cases cell‐center user's (CCU's) signal‐to‐interference ratio (SIR), cell‐edge user's (CEU's) SIR, and inner radius (IR) are implemented. These closed forms are used to complete the comparison of all techniques using numerous performance evaluation metrics. The results show, that as unpredicted, the performance of R‐A sectored FFR is close to that of R‐A sectored FFR BF in low SIR threshold and high path‐loss exponent (PLE) ranges. Therefore, R‐A sectored FFR is preferred to be used from the perspectives of network cost and power consumption. Furthermore, vertical BF shows performance close to that of 3D BF in low PLE range. Consequently, using vertical BF is preferable with regard to the energy preservation and network budget. Moreover, it is noticed that BS that applies BF arrangement outperforms other arrangements when vertical or horizontal BF technique is applied. Additionally, the arrangement of both RS and BS that apply BF is superior to the other arrangements when 3D BF is used. But, as expected, it does worse than the others if the other BF techniques are applied. The work results achieve much higher CEU SIR enhancement. Therefore, the probability of outage is decreased. Then, rate of served users by the network is heightened. Accordingly, the total network cost is reduced. So this study advances the network performance while maintaining lower network cost.

Regulatory Cooperation in Securities Market Regulation: Perspectives from Australia

The global financial crisis highlighted the interconnectedness of international financial markets and the risk of contagion it posed. The crisis also emphasized the importance of supranational regulation and regulatory cooperation to address that risk. Yet, although capital flows are global, securities regulation is not. As a 2019 report by IOSCO notes, the regulatory challenges revealed during the global financial crisis have by no means dissipated over the last decade. Lack of international standards, or differences in the way jurisdictions implement such standards, can often result in regulatory-driven market fragmentation. This article considers a range of cooperative techniques designed to achieve international regulatory harmonization and effective cross-border financial market supervision. It discusses three major techniques: (i) transgovernmental networks of financial regulators; (ii) complex multilateral arrangements; and (iii) mutual recognition agreements, and considers the benefits and downsides of each of these regulatory mechanisms. The article focuses particularly on developments in Australia. It examines, for example, a high profile cross-border supervisory experiment, the US-Australian Mutual Recognition Agreement, which the SEC and Australia’s business conduct regulator, ASIC, signed in 2008. This was the first agreement of its kind for the SEC. The article also considers some key regulatory developments in Australia and Asia since the time of the US-Australian Mutual Recognition Agreement.

Regulatory Cooperation in Securities Market Regulation: Perspectives from Australia

The global financial crisis highlighted the interconnectedness of international financial markets and the risk of contagion it posed. The crisis also emphasized the importance of supranational regulation and regulatory cooperation to address that risk. Yet, although capital flows are global, securities regulation is not. As a 2019 report by IOSCO notes, the regulatory challenges revealed during the global financial crisis have by no means dissipated over the last decade. Lack of international standards, or differences in the way jurisdictions implement such standards, can often result in regulatory-driven market fragmentation. This article considers a range of cooperative techniques designed to achieve international regulatory harmonization and effective financial market supervision. It includes discussion of a high profile cross-border supervisory experiment, the 2008 US-Australian Mutual Recognition Agreement, which was the first agreement of its kind for the SEC. The article also examines some key regulatory developments in Australia and Asia since the time of the US-Australian Mutual Recognition Agreement.

A Distributed Cooperative Localization Strategy in Vehicular-to-Vehicular Networks.

This work develops a distributed message-passing approach to cooperative localization for autonomous mobile vehicles that communicate via mm-wave wireless connection in vehicle-to-vehicle networks. Vehicles in the network obtain the measurement information about the relative distance and the angle of arrival from the mm-wave connections made with each other. Some vehicles may obtain knowledge about their absolute position information of different quality, for example, via additional localization feature. The main objective is to estimate the locations of all vehicles using reciprocal exchanges of simple information called a message in a distributed and autonomous way. A simulation is developed to examine the performance of the localization and navigation of vehicles under various network configurations. The results show that it does provide better positioning results in most cases and there are also several cases where the use of the cooperative technique adapts to design parameters such as accuracies of measurement equipment, and initial position estimates, that can affect the localization performance.