Dynamics of Hybrid Cooperation

This paper investigates the security and data reliability in Unattended Wireless Sensor Networks (UWSNs). We deduce an analytical model for Self-Healing scheme based on Cluster Controlled Mobility (SH-CCM) for UWSNs. The SH-CCM is based on mobility inside a cluster of sick sensor beside the hybrid cooperation from both reactive and proactive peers to enhance self-healing probability. The analytical analysis of SH-CCM will ensure that both mobility and hybrid cooperation from both reactive and proactive peers within the cluster of sick sensor will enhance the Cooperation, Self-Healing, data security and reliability. Therefore, the proposed SH-CCM scheme will help the sick sensor to self-heal and restore its backward secrecy faster and better than the schemes without controlled mobility. A set of Analytical results are carried out to demonstrate the effectiveness of the proposed SH-CCM scheme in the presence of an Adversary (ADV). The obtained results ensure that the proposed scheme has a better performance; it archives a probability of BSe to be compromised of 0.04 while CHSHRD [1] is 0.065.

Machine-to-machine (M2M) communication plays an important role in various kinds of intelligent networks. In this study, a hybrid cooperation scheme for data collection in hierarchical smart building networks (SBN) is proposed under the framework of M2M communications. The hierarchical network structure means that the data collection process is carried out via multi-layer communications. In the first layer, smart metres organise themselves into clusters and send information to the cluster-heads. Then all cluster-heads forward the received information to the base station automatically in the second layer. In particular, the roles of cluster-head can be acted by either fixed nodes or user terminals in the building, and this endow a hybrid cooperation mode to the data collection process. To construct the network structure and utilise the resources efficiently, the authors first provide some theoretical analysis on the influence of network structure and bandwidth constraints. Then a distributed scheme for joint structure formation and subband allocation is proposed based on coalitional game theory. Furthermore, for the feasibility of this scheme in practical applications, some improvements of the proposed scheme have also been made at last. The advantages of the proposed scheme are verified by simulation results.

Hybrid work has become increasingly popular in the aftermath of the Covid-19 pandemic. Despite its popularity, many organisations still strive to find an answer to "how to do hybrid cooperation right''. Enabling collaboration across digital and physical workspaces, participants, and practices is a great challenge, as it inevitably introduces asymmetric relations, incongruences in frames of reference, and misaligned ecosystems and technical infrastructures. The paper investigates approaches used to manage asymmetries in hybrid work settings and their impact on cooperation. Through a multi-sited ethnographic study, we reveal a prevalent reliance on mimicking tools and practices native to fully physical or fully digital settings in the hybrid space. These mimicking practices often arise because the hybrid work setting is viewed through a deficit lens, whereby it is perceived as lacking certain elements (e.g., body, voice, mobility) and access to modalities from especially the physical setting, thereby necessitating the need for compensation work. To provide vocabulary to conceptualize and articulate this type of practice, we introduce the concept compensation work, referring to work that is carried out to offset a deficiency or absence that has been identified, aiming to restore and re-establish a familiar state that has vanished. While compensating through mimicking is intuitive, such approaches assume that our known practices and interactions from the physical workspace can indeed be translated to another context, neglecting the fact that changing the medium inevitably impacts the message. Thus, cooperative practices and interactions taking place in the physical workspace do not remain the same when unfolding in the hybrid space. Finally, we suggest that in order to design technologies and practices that support hybrid cooperation we first need to acknowledge the hybrid workspace as a distinct "third space'' next to the fully remote and fully physical workspace. This includes following an experience-driven approach to hybrid cooperation, encouraging the design of innovative interactions that extend beyond merely compensating for asymmetries and leveraging the unique capabilities and affordances of these settings.

In this paper, we use a simple asynchronous coordination language to design some complex hybrid cooperation schemes for solving optimisation problems. The language allows us to specify the interaction between complete and incomplete constraint solvers in a clear and uniform way. Experimental results show the benefits of such hybrid cooperations in terms of efficiency.

This paper deals with throughput oriented adaptive modulation and coding (AMC) techniques combined with cooperative protocols where terminals are constrained by half-duplex assumption and average total network power. We propose a novel hybrid cooperation protocol that switches from cooperative to non-cooperative transmission based on the momentary direct source-destination link quality. Then, we propose an <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">hybrid</i> cooperative <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AMC</i> mechanism, which combines AMC with hybrid cooperation. Simulation results show that our proposal improves the average system performance and reduces the average cooperation signaling cost.

SUMMARYIn this paper, we investigate the symbol error rate (SER) performance and power allocation for hybrid cooperation (HC) system in a Rayleigh fading environment. Specifically, we derive closed‐form and approximate SER expressions for the HC system by using the moment generating function (MGF)‐based approach. However, the resultant SER expressions contain an MGF of the harmonic mean of two independent random variables, which is not tractable in SER analysis. Then, we present simple and tight bounds on the SER to show the asymptotic behavior of the HC system. It is shown that the HC system achieves full diversity order. On the basis of the tight SER bound, the power allocation is investigated. It is found that the optimal power allocation (OPA) of the HC system does not depend on the fading parameter of the source‐to‐destination channel and it only depends on the channel links related to the relay. With the increase of the ratio of mean channel power gains (i.e., the ratio of the relay‐to‐destination channel gain to the source‐to‐relay channel gain), more performance gain can be acquired by using the OPA scheme. Finally, the analytical results are validated through computer simulations. Copyright © 2012 John Wiley &amp; Sons, Ltd.

In this paper, symbol-error-rate (SER) performance analysis is provided for hybrid cooperation (HC) system in an asymmetric fading environment where the source-to-relay and the relay-to-destination channels experience independent Rayleigh/Rician and Rician/Rayleigh fading, respectively, while the direct channel link between the source and the destination is subject to Rayleigh fading. Unlike most existing relaying protocols which use amplify-and-forward (AF) or decode- and-forward (DF) protocol separately, the HC system takes advantage of both AF and DF protocols simultaneously. Based on the theoretical analysis, analytical expressions for the moment generating function (MGF) of the end-to-end signal-to-noise ratio (SNR) are derived and used to evaluate the SER performance of the HC system with M -ary phase shift keying ( M -PSK) modulation. Numerical and simulation results are presented to verify the theoretical analysis, where we also illustrate the impact of the Rician factors on system performance.

Realizing high-accuracy transmission in high-rate data broadcasting networks with heterogeneous users via cooperative communication

Cooperation under uncertainty in distributed expert systems

In response to the negative effects caused by structures of the dominant agricultural system and new market opportunities, increasing food supply structures have re-emerged in the urban-rural context of industrialized countries in recent years. These food supply structures often accompany new forms of hybrid cooperation models, including actors and institutions that have not shared resources previously. They form new alliances for sustainable transformation in the agri-food sector. Simultaneously, discourse has arisen in science and practice about the sustainability potential of such hybrid cooperation, referring to a lack of critical systematization and the necessity for creating an assessment concept. From the latter, one could draw conclusions about the transformative potential of such cooperation models and their potential to serve as blueprints for other regions. In this conceptual paper, a classification approach derived from social enterprise literature is elaborated, extended, and evaluated, to design a classification of new hybrid cooperation models that allow comparisons between regions and are sensitive to their dynamics. We show in an application how the classification approach, considering the dimensions “actors”, “resources”, and “actions”, serves to discover patterns in the development of short food-supply chain practices, identifying individual transition paths and, thus, making statements about their sustainability and challenges.

In wireless systems where transmitters are subject to a strict received power constraint, such as in underlay cognitive radio networks, cooperative communication is a promising strategy to enhance network performance, as it helps to improve the coverage area and outage performance of a network. However, this comes at the expense of increased resource utilization. To balance the performance gain against the possible over-utilization of resources, we propose a hybrid-cooperation technique for underlay cognitive radio networks, where secondary users cooperate only when required. Various performance measures of the proposed hybrid-cooperation technique are analyzed in this paper, and are also further validated numerically.

Efficient cooperative communication protocols are viewed as one of the mechanisms for increasing the diversity order, robustness and energy efficiency of a wireless communication system. Innovative concepts such as opportunistic relay cooperative transmission coupled with adaptive transmission may drive to low power consumption while keeping advantage of the diversity gain offered by the adaptive mechanisms. The goal of this paper is to investigate the effectiveness of the hybrid cooperation protocols proposed in (Strinati et al., 2007) for wide-band wireless mobile communication systems, such for instance IEEE 802.16e. We modify the hybrid cooperation protocol to take into account the non ideal behavior of the real system in the hybrid cooperation controller criterion. Simulation results show that our proposal improves the average system performance and reduces the average cooperation cost.

In this work, we study a cooperative network with multiple full-duplex buffer-aided relays. A hybrid cooperative relaying policy is proposed that employs power adaptation and consists of two alternative schemes: (i) full-duplex transmission through the relay which requires the least total power expenditure and loop interference is mitigated through power adaptation; (ii) buffer-aided max - link selection with power adaptation, when full-duplexity is not feasible. Aiming to reduce the overhead of channel state information (CSI) acquisition and processing, we propose a suboptimal distributed method for relay selection, for which the network performance is not degraded significantly. We show that power adaptation offers reduced overhead of CSI acquisition. Numerical results and comparisons with other state-of-the-art relaying schemes are provided and performance evaluation in terms of throughput, power minimization and switching rate, show the benefits of the proposed hybrid scheme.

A new improve Swarm Intelligence Algorithm which is named Hybrid Leader Cooperation Algorithm (HLCA) is proposed in this paper. The HLCA first separates the individuals by its rank. According to its rank, if the individual is a good one then cooperation with the others by conservation of the momentum operator; else it studied from the rest individuals and the leader for searching. Finally, the numerical experiments results show that the HLCA is better than the PSO and the Multi-Parent Evolutionary Algorithm (MPEA).The HLCA not only can avoid to the local optimal but also accelerate the convergence rate.

Understanding the molecules’ spatial organization in order to understand their functions is a challenge of recent molecular and structural biology. There are three phases for the analysis of molecular structures and molecular dynamics, and a large number of software. Modeling is the numerical reproduction of the 3D structures, based on biological knowledge and hypotheses. Visualization is the observation and the configuration of the models’ parameters. Then, interactions through desktop or Virtual Reality (VR) devices range from spatial manipulation to sensory perception of biological reactions. This can be called in virtuo analysis. It puts the human expert as an actor at the center of the simulation rather than an observer of automatic simulation results. It combines the advantages of computing power and advanced Human-Computer Interaction (HCI) techniques: comfort of natural interactions, physical and psychological immersion, efficiency of multimodal renderings (visual, audio and haptic), etc. This will lead to a fully hybrid cooperation between simulators and experts, for example to overcome algorithmic limits with informal human knowledge and expertise.