Artykuły w czasopismach na temat „Cooperative Multicast System”

Wireless sensor networks are formed by connected sensors that each have the ability to collect, process, and store environmental information as well as communicate with others via inter-sensor wireless communication. The many-to-one communication pattern used by sensor nodes in most of the data gathering applications leads to such unbalanced energy consumption. Cluster-based protocols attempt to solve this problem by load balancing within the cluster and rotating the job of cluster head every few rounds. In this paper, in order to achieve efficient utilization of wireless resources, we propose an opportunistic network-coded cooperative multicast scheme, which can select appropriate relays by synthetically considering location and instantaneous channel state information to improve the network performance than direct multicast with non additional power consumption.

With the rapid advance in multimedia streaming and multicast transport technology, current IP multicast protocols, especially PIM-SM, become the major channel delivery mechanism for IPTV system over Internet. The goals for IPTV service are to provide two-way interactive services for viewers to select popular program channel with high quality for watching during fast channel surfing period. However, existing IP multicast protocol cannot meet above QoS requirements for IPTV applications between media server and subscribers. Therefore, we propose a cooperative scheme of hybrid-tree based on explicit routed multicast, called as HT-ERM to combine the advantages of shared tree and source tree for QoS-supported IPTV service. To increase network utilization, the constrained shortest path first (CSPF) routing algorithm is designed for construction of hybrid tree to deliver the high-quality video stream over watching channel and standard quality over surfing channel. Furthermore, the Resource Reservation Protocol- Traffic Engineering (RSVP-TE) is used as signaling mechanism to set up QoS path for multicast channel admission control. Our simulation results demonstrated that the proposed HT-ERM scheme outperforms other multicast QoS-based delivery scheme in terms of channel switching delay, resource utilization, and blocking ratio for IPTV service.

This paper proposes a new transmission strategy for device-to-device (D2D) multicast cooperative communication systems based on Simultaneous Wireless Information and Power Transfer (SWIPT) technology. The transmission block is divided into two slots. In the first slot, the source user transmits the information and energy to the help user by SWIPT. In the second slot, the help user uses the cellular spectrum and forwards the information to multiple receivers by using harvested energy. In this paper, we aim to maximize the total system rate, and to tackle the problem, we propose a two-step scheme: In the first step, the resource allocation problem is solved by linear programming. In the second step, the power-splitting coefficient value is obtained by taking the benefit of help user into account. Numerical results show that the proposed strategy not only effectively improves the overall throughput and spectrum efficiency but also motivates the cooperation.

The original user relay (UR) selection scheme of non-orthogonal multiple access-based cooperative opportunistic multicast scheme, which realizes inter-group cooperation between two multicast groups, ignores the distribution trend of candidate UR in the cell and adopts fixed efficient relay selection range (ERSR) to select UR. It results in high UR selection ratio. Then the coverage efficiency, defined as the ratio of successfully received users to URs, is low. To tackle this problem, a range-division user relay (RDUR) selection scheme is proposed in this paper. Firstly, it divides the circular coverage range of base station into several continuous annular areas (AAs). Secondly, different ERSRs are assigned to unsuccessfully received users in different AAs. Under different ERSR assignments, the performances of UR selection ratio and coverage ratio are analyzed. Lastly, the radius set of ERSR that optimizes system coverage efficiency is used to perform UR selection. From simulation results, with different radius sets, analytical results of UR selection ratio and coverage ratio match well with their simulated ones. It is proved that ERSR allocation affects UR selection ratio and coverage ratio. With RDUR scheme, coverage efficiency increases by at least 14% and capacity efficiency has also been improved.

Edge networks employ local computing and caching resources to process data, thus alleviating the bandwidth pressure on backbone networks and improve users’ quality of experience. System capacity is one of the key metrics to evaluate the performance of edge networks. However, maximizing system capacity in edge scenarios faces challenges due to the dynamical user sessions and the changing content popularity. This study reports on the influence of multicast communication on the capacity of edge caching networks. When large amounts of content are requested simultaneously or over a short period, one-to-one unicast transmission will consume copious network resources due to repetitious transmission. To solve this problem, this study used the one-to-many multicast scheme to realize cooperative transmission between edge servers. First, multiple copies of the content are distributed to multiple small base stations (SBSs) based on the content’s popularity and the SBSs’ cache sizes. Second, a multicast tree is constructed by using, as the root node, the SBS that stores the content. Third, the content is transmitted along the path of the multicast tree to each end-user. Finally, a simulation platform is constructed to analyze the performance of the two transmission schemes. The results of simulating on edge caching networks show that multicast communication responds well to users’ requests even when the requested content requires sudden transmission, is highly popular or is requested often within short time. This system’s capacity has been significantly improved compared to the classical methods.

This paper studies a multi-user network model based on sparse code multiple access (SCMA), where both unicast and multicast services are considered. In the direct transmission scheme, the communication between the base station (BS) and the users is completed with one stage, in which the relay is inexistent. In the two-stage cooperative transmission scheme, any number of relays are placed to improve the reliability of wireless communication system. The BS broadcasts the requested message to users and relays in the first stage, and the successful relays forward the message to unsuccessful users in the second stage. To characterize the performance of these two schemes, we derive the exact and approximate expressions of average outage probability. Furthermore, to take full advantage of the cooperative diversity, an optimal power allocation and relay location strategy in the high signal-to-noise ratio (SNR) regime is studied. The outage probability reaches the minimum value when the first stage occupies half of the total energy consumed. Simulation and analysis results are presented to demonstrate the performance of these two schemes. The results show that the two-stage cooperative scheme effectively reduce the average outage probability in SCMA network, especially in the high SNR region.

The grouping method is an efficient transmitting strategy in a spatial diversity system. In this paper, relay-based grouping methods in satellite terrestrial cooperative wireless networks are proposed. The proposed methods focus on finding out the best two signals received from relay stations in a user’s neighborhood and use the advantage of space diversity to overcome the effect of channel fading. A grouping method, called the pilot-based grouping method was proposed in our previous work. In order to improve the grouping success rate and the channel capacity, a modified grouping method is proposed. In addition, for a single relay the modified grouping method can achieve better results than the pilot-based grouping method. In the end, several analysis strategies of the grouping method for multimedia broadcast and multicast services in satellite terrestrial cooperative networks are proposed. The simulation results show the performance improvement and the system evaluation for different quality of services in the demanded relay-based cooperative networks. The proposed modified grouping methods can be widespread in any relay-based cooperative networks.

Scalable Video Coding (SVC) streaming multicast is considered as a promising solution to cope with video traffic overload and multicast channel differences. To solve the challenge of delivering high-definition SVC streaming over burst-loss prone channels, we propose a social-aware cooperative SVC streaming multicast scheme. The proposed scheme is the first attempt to enable D2D cooperation for SVC streaming multicast to conquer the burst-loss, and one salient feature of it is that it takes fully into account the hierarchical encoding structure of SVC in scheduling cooperation. By using our scheme, users form groups to share video packets among each other to restore incomplete enhancement layers. Specifically, a cooperative group formation method is designed to stimulate effective cooperation, based on coalitional game theory; and an optimal D2D links scheduling scheme is devised to maximize the total decoded enhancement layers, based on potential game theory. Extensive simulations using real video traces corroborate that the proposed scheme leads to a significant gain on the received video quality.

How to deal with the increasing video traffic and diverse service demands while ensuring the security of transmission is an open issue in the multimedia Internet of Things (IoT). This paper addresses this issue and studies a secure delivery scheme under a multicast scenario in the presence of multiple eavesdroppers where small base stations (SBSs) can send videos to users cooperatively. Aiming at potential eavesdroppers, a channel model including artificial noise is introduced to reduce the harm of illegal data acquisition. A network quality of experience (QoE) optimization problem is first formulated to account for video quality and delivery delay. In order to solve the nonconvex problem, the successive convex approximation (SCA) technique is applied to optimize multicast group beamforming, reduce the possibility of multicast video eavesdropping, and select video quality where a heuristic scheme is proposed to maximize the network QoE. The effectiveness of the proposed scheme is finally validated by extensive simulations in terms of algorithm convergence performance and network QoE-enhanced performance.

The refinement of gigabit switches is an unproven challenge. In fact, few biologists would disagree with the refinement of lambda calculus, which embodies the intuitive principles of networking. We explore a novel framework for the synthesis of the producer-consumer problem (TACKY), which we use to show that the foremost cooperative algorithm for the synthesis of operating systems by Sun et al. is Turing complete.

Demand response (DR) programs are designed to affect the energy consumption behavior of end-users in smart grid. However, most existing pricing designs for DR programs ignore the influence of end-users’s diversity and personal preference. Thus, in this paper, we investigate an incentive pricing design based on the utility maximization rule with consideration of end-users’ preference and appliances’ operational patterns. In particular, the utility company determines the pricing policy by trading off the budget revenue and social obligation, while each end-user aims to maximize their own utility profits with high satisfaction level by scheduling multiclass appliances. We formulate the conflict and cooperative relationship between the utility company and end-users as a Stackelberg game, and the equilibrium points are obtained by the backward induction method, which exists and is unique. At the equilibrium, the utility company adopts real-time pricing (RTP) scheme to coordinate end-users to fulfill the benefit of themselves, i.e., under such price, end-users automatically maximize overall utility profits of the overall system. We propose a distributed algorithm and an adaptive pricing scheme for the utility company and end-users to jointly achieve the best performance of the entire system. Finally, extensive simulation results based on real operation data show the effectiveness of the proposed scheme.

Robot introspection is expected to greatly aid longer-term autonomy of autonomous manipulation systems. By equipping robots with abilities that allow them to assess the quality of their sensory data, robots can detect and classify anomalies and recover appropriately from common anomalies. This work builds on our previous Sense-Plan-Act-Introspect-Recover (SPAIR) system. We introduce an improved anomaly detector that exploits latent states to monitor anomaly occurrence when robots collaborate with humans in shared workspaces, but also present a multiclass classifier that is activated with anomaly detection. Both implementations are derived from Bayesian non-parametric methods with strong modeling capabilities for learning and inference of multivariate time series with complex and uncertain behavior patterns. In particular, we explore the use of a hierarchical Dirichlet stochastic process prior to learning a Hidden Markov Model (HMM) with a switching vector auto-regressive observation model (sHDP-VAR-HMM). The detector uses a dynamic log-likelihood threshold that varies by latent state for anomaly detection and the anomaly classifier is implemented by calculating the cumulative log-likelihood of testing observation based on trained models. The purpose of our work is to equip the robot with anomaly detection and anomaly classification for the full set of skills associated with a given manipulation task. We consider a human–robot cooperation task to verify our work and measure the robustness and accuracy of each skill. Our improved detector succeeded in detecting 136 common anomalies and 368 nominal executions with a total accuracy of 91.0%. An overall anomaly classification accuracy of 97.1% is derived by performing the anomaly classification on an anomaly dataset that consists of 7 kinds of detected anomalies from a total of 136 anomalies samples.

Editorial – Revista Ambiente Contábil – Volume 13 – Número 2 – Ano 2021 (Jul./Dez. 2021) A Revista Ambiente Contábil (Ambiente) apresenta na sua 26ª edição 19 (dezenove) artigos que tratam de assuntos relevantes para a área contábil; 01 (uma) resenhas de livro e 10 (dez) artigos no idioma inglês e 01 (um) artigo em espanhol. Seção 1: Contabilidade Aplicada ao Setor Empresarial Artigo 1 - Determinantes do spread de instituições financeiras cooperativas e bancos comerciais no Brasil de Gustavo Antônio Faleiro Bernardes, Aziz Xavier Beiruth e Talles Vianna Brugni com o objetivo de analisar os fatores que determinam o spread de instituições financeiras cooperativas e bancos comerciais, com o intuito de identificar indícios de vantagem competitiva entre cooperativas e bancos. Artigo 2 - Gerenciamento tributário: análise da influência sobre o custo do capital próprio das empresas brasileiras de Hana Belisa Marques de Freitas, Caritsa Scartaty Moreira, Annandy Raquel Pereira da Silva, Ítalo Carlos Soares do Nascimento, Geison Calyo Varela de Melo com o objetivo de investigar se o gerenciamento tributário influencia no custo de capital próprio das empresas brasileiras listadas no Brasil, Bolsa e Balcão (B3) no período de 2014 a 2018. Artigo 3 - Gerenciamento de resultados e governança corporativa: uma análise a partir da adoção das IFRS no Brasil de Bruno Chacon Prata e Leonardo Flach com o objetivo de analisar se a adoção das International Financial Reporting Standards (IFRS) fortaleceu a relação negativa entre gerenciamento de resultados e boas práticas de governança corporativa, sendo elas: os níveis diferenciados de governança corporativa da B3, a presença de um conselho de administração independente e se a companhia é auditada por uma Big Four. Artigo 4 - Relevância do Goodwill e períodos de recessão: evidências no mercado de capitais brasileiro de Taise Feltes, Ernesto Fernando Rodrigues Vicente, Alex Mussoi Ribeiro com o objetivo de analisar a relevância do Goodwill para o mercado de capitais brasileiro e verificar possíveis diferenças em períodos de recessão econômica. Artigo 5 - Mensuração a valor justo e seus impactos nos honorários de auditoria: evidências no mercado brasileiro de Edson Vinícius Pontes Bastos, Luciana Holtz, Odilanei Morais dos Santos com o objetivo de verificar o impacto do uso da mensuração a valor justo sobre os honorários de auditoria, diferenciando-se inclusive o período pré e pós adoção do CPC 46. Artigo 6 - Disclosure ambiental dos relatórios corporativos da empresa Natura à luz da teoria da divulgação voluntária de Claúdia Voges, Cleber Broietti e Suliani Rover com o objetivo de analisar o nível de disclosure ambiental dos relatórios de sustentabilidade da Natura Cosméticos S.A., no período de 2001 a 2019, à luz da teoria da divulgação voluntária. Artigo 7 - Diversificação das receitas em cooperativas de crédito de livre admissão do Brasil e sua influência sobre desempenho financeiro de Lucas Ribeiro e de Rosiane Maria Lima Gonçalves com o objetivo de analisar o efeito da diversificação das receitas sobre o desempenho financeiro das cooperativas de crédito de livre admissão brasileiras, no período de 2014 a 2018. Artigo 8 - PROFUT: uma análise da estrutura de capital de times brasileiros de Erika Maia da Rocha, Francisco Ícaro Silvério de Oliveira e de Rosângela Queiroz Souza Valdevino com o objetivo de verificar a relação existente entre o atendimento aos requisitos pertinentes à adesão e permanência no PROFUT e a situação econômico-financeira de clubes de futebol brasileiros listados no Ranking Nacional de Clubes (RNC). Artigo 9 - O efeito da introdução de market makers na liquidez das ações: evidências no mercado acionário brasileiro de Gabriel Augusto de Carvalho, João Eduardo Ribeiro e Laíse Ferraz Correia com o objetivo de analisar se a introdução de market makers nas negociações das ações de empresas brasileiras listadas na bolsa de valores brasileira é uma medida válida para a elevação da liquidez de mercado desses ativos. Artigo 10 - Dez anos de trajetória acadêmica da Revista Advances in Scientific and Applied Accounting (ASAA) à luz de sua produção científica de Henrique César Melo Ribeiro com o objetivo de analisar a trajetória e o estado da arte da produção científica dos artigos divulgados na revista ASAA de 2008 a 2017. Seção 2: Contabilidade Aplicada ao Setor Público e ao Terceiro Setor Não houve submissão. Seção 3: Pesquisas de Campo sobre Contabilidade (Survey) Artigo 1 - Nível de conhecimento dos profissionais de contabilidade de Três Lagoas (MS) sobre contabilidade ambiental, gestão e legislação ambiental de Sirlei Tonello Tisott, Sílvio Paula Ribeiro, Tamires Sousa Araújo, Cinthia da Costa Pontes e Jhonatan Verissímo da Silva com o objetivo de analisar o nível de conhecimento dos profissionais de contabilidade de Três Lagoas (MS) sobre contabilidade ambiental, gestão e legislação ambiental. Artigo 2 - Competências docentes e aprendizagem em controladoria em programas de mestrado: uma investigação da percepção discente de Silvana Anita Walter, Jhessica Tamara Kremer, Jéssica Karine de Oliveira Gomes e Anna Caroline Priebe com o objetivo de compreender a percepção dos discentes sobre a relação entre competências docentes e aprendizado de controladoria em programas de mestrado em contabilidade no sul e sudeste do Brasil. Artigo 3 - Fatores possíveis de promover ou comprometer a motivação de estudantes de ciências contábeis: análise em uma instituição de ensino de Minas Gerais de Breno da Silva Costa, Janaina Gonçalves de Faria, Bruna Camargos Avelino e Talles Vianna Brugni com o objetivo de avaliar os fatores que influenciam a motivação de estudantes do curso de Ciências Contábeis de uma Instituição de Ensino Superior localizada em Minas Gerais, à luz da Teoria da Autodeterminação. Artigo 4 - Sentimentos de culpa vivenciados na pós-graduação de Ricardo Biernaski Kachenski, Rayane Camila da Silva Sousa, Pavel Elias Zepeda Toro, Flaviano Costa e Romualdo Douglas Colauto com o objetivo de verificar o nível de concordância dos estudantes quanto aos sentimentos de culpa vivenciados na pós-graduação stricto sensu. Artigo 5 - Dificuldades dos municípios da região metropolitana cearense em aderir ao processo de convergência da contabilidade pública: um estudo multicaso de Thaís da Silva Moura, Roberto Sérgio do Nascimento e Ricardo Viotto com o objetivo de avaliar as percepções dos municípios brasileiros quanto ao processo de convergência da contabilidade pública às normas internacionais, iniciado em 2008, tendo em vista a importância destes entes federados na prestação primária de bens e serviços públicos à sociedade. Artigo 6 - Utilização de sistemas de informações gerenciais sob a perspectiva de produtores rurais de Andressa Bittarello, Stella Maris Lima Altoé e Ricardo Suave com o objetivo de avaliar os reflexos da utilização de Sistemas de Informações Gerenciais (SIG) na gestão das pequenas empresas do ramo da atividade rural. Artigo 7 - Formação didático-pedagógica dos egressos da pós-graduação stricto sensu em ciências contábeis de uma instituição federal de ensino superior de Thayná de Oliveira Fernandes, Valdineide dos Santos Araújo e Paulo Roberto Nóbrega Cavalcanti com o objetivo de investigar a formação didático-pedagógica no curso de pós-graduação em Ciências Contábeis de uma Instituição Federal de Ensino Superior. Artigo 8 - As competências do contador sob a ótica dos profissionais contábeis da cidade de Vitória de Santo Antão – PE de Andreza Moura dos Santos, Tania Nobre Gonçalves Ferreira Amorim e Tácio Marques da Cunha com o objetivo de identificar quais são as competências desejáveis ao contador sob a ótica dos profissionais contábeis, que trabalham nos escritórios da cidade de Vitória de Santo Antão, em Pernambuco. Seção 4: Casos de Ensino Aplicados a Contabilidade Artigo 1 - Caso para ensino: a água que eu visto de Aracéli Cristina de Sousa Ferreira, Luiz Carlos Miranda e Juliana Molina Queiroz com o objetivo de possibilitar a aprendizagem dos alunos sobre os impactos ambientais e seus efeitos, além de permitir que os mesmos utilizam métodos de valoração econômica do meio ambiente para internalizar as externalidades referentes aos impactos ambientais e sociais. Seção 5: Resenhas de Teses, Dissertações e Livros sobre Contabilidade Resenha 1 - Resenha do livro: Fundamentos éticos da tributação: em busca de uma Teoria da Justiça em Kant, de Rodrigues R. S. Belo Horizonte: D’Plácido, 2021, 224p. ISBN: 978-65-5589-139-3. Autor da Resenha: Adriano da Silva Ribeiro Seção 6: Banco de Dados (Arquivos suplementares em Excel) Sem publicações. Seção 7: Internacional (S7) ENGLISH Section 1 Article 2 (Section 1) – Tax management: analysis of the influence on the equity cost of Brazilian companies of Hana Belisa Marques de Freitas, Caritsa Scartaty Moreira, Annandy Raquel Pereira da Silva, Ítalo Carlos Soares do Nascimento and Geison Calyo Varela de Melo. The present study sought to investigate whether tax management influences the equity cost of Brazilian companies listed in Brazil, Bolsa e Balcão (B3) from 2014 to 2018. Article 3 (Section 1) - Earnings management and corporate governance: an analysis based on the adoption of IFRS in Brazil of Bruno Chacon Prata and Leonardo Flach. This paper aims to analyze whether the adoption of the International Financial Reporting Standards (IFRS) strengthened the negative relationship among earnings management and corporate governance best practices, which are: B3’s differentiated levels of corporate governance, the presence of a board of independent directors and whether the company is audited by a Big Four or not. Article 5 (Section 1) - Fair value measurement and its impact on audit fees: evidence in the Brazilian market of Edson Vinícius Pontes Bastos, Luciana Holtz and Odilanei Morais dos Santos. The purpose is to verify the impact of using the measurement at fair value on the audit fees, differentiating even the period before and after the adoption of IFRS 13 (CPC 46). Article 8 (Section 1) - PROFUT: An analysis of the capital structure of Brazilian soccer teams of Erika Maia da Rocha, Francisco Ícaro Silvério de Oliveira and Rosângela Queiroz Souza Valdevino. The research intends to verify the relationship between meeting the requirements for joining and staying at PROFUT and the economic and financial situation of Brazilian football clubs listed in the Ranking Nacional de Clubes (RNC). Article 9 (Section 1) - The effect of the introduction of market makers on stock liquidity: evidence from the Brazilian stock market of Gabriel Augusto de Carvalho, João Eduardo Ribeiro and Laíse Ferraz Correia. This study aimed to analyze whether the introduction of market makers as specialized intermediaries in the trading of stocks listed on the Brazilian stock exchange is a useful procedure for increasing the market liquidity of these assets. Section 3 Article 5 (Section 3) - Difficulties of municipalities in the cearense metropolitan region in adhering to the public accounting convergence process: a multi-study of Thaís da Silva Moura, Roberto Sérgio do Nascimento and Ricardo Viotto. The purpose of this multi-case study is to evaluate the perceptions of Brazilian municipalities regarding the process of convergence of public accounting to international standards, initiated in 2008, considering the importance of these federated entities in the primary provision of public goods and services to society. Article 6 (Section 3) - Use of management information systems from the perspective of farmers of Andressa Bittarello, Stella Maris Lima Altoé and Ricardo Suave. The purpose is to evaluate the impact of the use of Management Information Systems (MIS) in the management of small companies in the field of rural activity. Article 7 (Section 3) - Didactic-pedagogical training of stricto sensu graduate students in accounting sciences from a federal institution of higher education of Thayná de Oliveira Fernandes, Valdineide dos Santos Araújo and Paulo Roberto Nóbrega Cavalcanti. The present study aimed to investigate the didactic-pedagogical graduation in the postgraduate course in Accounting Sciences of a Federal Institution of Higher Education. Article 8 (Section 3) - The accountant's competences from the point of view of professionals working in the city of Vitória de Santo Antão - PE of Andreza Moura dos Santos, Tania Nobre Gonçalves Ferreira Amorim and Tácio Marques da Cunha. The present research aimed to identify which competences are desirable to the accountant from the perspective of the accounting professionals who work in the offices of the city of Vitória de Santo Antão, in Pernambuco. Section 4 Article 1 (Section 4) – Teaching case: the water I wear of Aracéli Cristina de Sousa Ferreira, Luiz Carlos Miranda and Juliana Molina Queiroz. This case aims to enable students to learn about environmental impacts and their effects and allow them to use methods of economic valuation of the environment to internalize externalities related to environmental and social impacts. The product in question is widely used what can make students identify themselves with the case. Then, they will be more interested in the problem identified in this case which is the non-internalization of externalities (social and environmental impacts). ESPAÑOL Artículo 4 (Sección 3) - Sentimientos de culpa experimentados en la posgraduación en Ricardo Biernaski Kachenski, Rayane Camila da Silva Sousa, Pavel Elias Zepeda Toro, Flaviano Costa y Romualdo Douglas Colauto. La investigación consiste en verificar el nivel de concordancia de los estudiantes con respecto a los sentimientos de culpa experimentados en la posgraduación stricto sensu. Boa leitura. Cordiais saudações! Prof. Dr. Maurício Corrêa da Silva Editor Gerente da Revista Ambiente Contábil

Ad Hoc network changes the location and configures itself. Cooperative Communication leverages the broadcast nature of the wireless channels and achieves the improvement in system capacity and delay. To manage the medium access interactions, an efficient Cooperative Medium Access Control (CMAC) protocol is used to improve the network performance in terms of lifetime and energy efficiency. By utility based relay selection strategy, performance is increased based on location information and residual energy. This strategy helps to select the best cooperative node with better channel condition, best relay and balanced energy consumption. However, the packet loss is not controlled. To overcome this, the proposed system using Collaborative Opportunistic Recovery Algorithm (CORA) which is designed for multicast applications with low packet loss and latency constraints. To recover peer-to-peer packet loss, Cached Packet Distance Vector (CPDV) protocol is used.

Problem definition: We study shared service whereby multiple independent service providers collaborate by pooling their resources into a shared service center (SSC). The SSC deploys an optimal priority scheduling policy for their customers collectively by accounting for their individual waiting costs and service-level requirements. We model the SSC as a multiclass [Formula: see text] queueing system subject to service-level constraints. Academic/practical relevance: Shared services are increasingly popular among firms for saving operational costs and improving service quality. One key issue in fostering collaboration is the allocation of costs among different firms. Methodology: To incentivize collaboration, we investigate cost allocation rules for the SSC by applying concepts from cooperative game theory. Results: To empower our analysis, we show that a cooperative game with polymatroid optimization can be analyzed via simple auxiliary games. By exploiting the polymatroidal structures of the multiclass queueing systems, we show when the games possess a core allocation. We explore the extent to which our results remain valid for some general cases. Managerial implications: We provide operational insights and guidelines on how to allocate costs for the SSC under the multiserver queueing context with priorities.

AbstractLinear broadcasting services, with a scheduled programming, constitute a paramount telecommunication service for today’s society. Although the existing technology is mature, current linear broadcast systems have serious limitations when providing service to moving users or users placed in areas with complex orography and poor signal quality. To overcome these limitations, 3GPP 5G standard has included a work item to support 5G multicast/broadcast services for future Release 17. This paper investigates the integration of point-to-point (unicast) communication with cellular multicast/broadcast on 5G technology to extend the current support of linear broadcasting services. This integration relies on the use mobile edge computing (MEC) at the 5G base station (gNB) to host a dynamic adaptive streaming over HTTP (DASH) server that is coordinated with the multicast transmission to complement the broadcast service. This approach join the reliability of point-to-point communications, with dedicated resources for each user, with the spectrum efficiency of multi-cast communications, where a set of users share common resources. The cooperation between those unicast and multicast schemes allows those users whose coverage is not good enough, to complete the linear broadcast flow through the point-to-point transmission via MEC. The benefits of such approach have been assessed with simulations in a realistic scenario that considers a vehicle moving across a sparsely populated region in southern Spain. Results reveals that throughput and bitrate playback (reproduction rate) are greatly improved when unicast/multicast integration is enabled since the number of stalling events is reduced significantly.