330 research outputs found
Pando: Personal Volunteer Computing in Browsers
The large penetration and continued growth in ownership of personal
electronic devices represents a freely available and largely untapped source of
computing power. To leverage those, we present Pando, a new volunteer computing
tool based on a declarative concurrent programming model and implemented using
JavaScript, WebRTC, and WebSockets. This tool enables a dynamically varying
number of failure-prone personal devices contributed by volunteers to
parallelize the application of a function on a stream of values, by using the
devices' browsers. We show that Pando can provide throughput improvements
compared to a single personal device, on a variety of compute-bound
applications including animation rendering and image processing. We also show
the flexibility of our approach by deploying Pando on personal devices
connected over a local network, on Grid5000, a French-wide computing grid in a
virtual private network, and seven PlanetLab nodes distributed in a wide area
network over Europe.Comment: 14 pages, 12 figures, 2 table
Orchestrating Service Migration for Low Power MEC-Enabled IoT Devices
Multi-Access Edge Computing (MEC) is a key enabling technology for Fifth
Generation (5G) mobile networks. MEC facilitates distributed cloud computing
capabilities and information technology service environment for applications
and services at the edges of mobile networks. This architectural modification
serves to reduce congestion, latency, and improve the performance of such edge
colocated applications and devices. In this paper, we demonstrate how reactive
service migration can be orchestrated for low-power MEC-enabled Internet of
Things (IoT) devices. Here, we use open-source Kubernetes as container
orchestration system. Our demo is based on traditional client-server system
from user equipment (UE) over Long Term Evolution (LTE) to the MEC server. As
the use case scenario, we post-process live video received over web real-time
communication (WebRTC). Next, we integrate orchestration by Kubernetes with S1
handovers, demonstrating MEC-based software defined network (SDN). Now, edge
applications may reactively follow the UE within the radio access network
(RAN), expediting low-latency. The collected data is used to analyze the
benefits of the low-power MEC-enabled IoT device scheme, in which end-to-end
(E2E) latency and power requirements of the UE are improved. We further discuss
the challenges of implementing such schemes and future research directions
therein
U-DiVE: Design and evaluation of a distributed photorealistic virtual reality environment
This dissertation presents a framework that allows low-cost devices to visualize and
interact with photorealistic scenes. To accomplish this task, the framework makes use of
Unity’s high-definition rendering pipeline, which has a proprietary Ray Tracing algorithm,
and Unity’s streaming package, which allows an application to be streamed within its
editor. The framework allows the composition of a realistic scene using a Ray Tracing
algorithm, and a virtual reality camera with barrel shaders, to correct the lens distortion
needed for the use on an inexpensive cardboard. It also includes a method to collect
the mobile device’s spatial orientation through a web browser to control the user’s view,
delivered via WebRTC. The proposed framework can produce low-latency, realistic and
immersive environments to be accessed through low-cost HMDs and mobile devices. To
evaluate the structure, this work includes the verification of the frame rate achieved by the
server and mobile device, which should be higher than 30 FPS for a smooth experience. In
addition, it discusses whether the overall quality of experience is acceptable by evaluating
the delay of image delivery from the server up to the mobile device, in face of user’s
movement. Our tests showed that the framework reaches a mean latency around 177 (ms)
with household Wi-Fi equipment and a maximum latency variation of 77.9 (ms), among
the 8 scenes tested.Esta dissertação apresenta um framework que permite que dispositivos de baixo
custo visualizem e interajam com cenas fotorrealísticas. Para realizar essa tarefa, o
framework faz uso do pipeline de renderização de alta definição do Unity, que tem um
algoritmo de rastreamento de raio proprietário, e o pacote de streaming do Unity, que
permite o streaming de um aplicativo em seu editor. O framework permite a composição
de uma cena realista usando um algoritmo de Ray Tracing, e uma câmera de realidade
virtual com shaders de barril, para corrigir a distorção da lente necessária para usar um
cardboard de baixo custo. Inclui também um método para coletar a orientação espacial
do dispositivo móvel por meio de um navegador Web para controlar a visão do usuário,
entregue via WebRTC. O framework proposto pode produzir ambientes de baixa latência,
realistas e imersivos para serem acessados por meio de HMDs e dispositivos móveis de
baixo custo. Para avaliar a estrutura, este trabalho considera a verificação da taxa de
quadros alcançada pelo servidor e pelo dispositivo móvel, que deve ser superior a 30 FPS
para uma experiência fluida. Além disso, discute se a qualidade geral da experiência é
aceitável, ao avaliar o atraso da entrega das imagens desde o servidor até o dispositivo
móvel, em face da movimentação do usuário. Nossos testes mostraram que o framework
atinge uma latência média em torno dos 177 (ms) com equipamentos wi-fi de uso doméstico
e uma variação máxima das latências igual a 77.9 (ms), entre as 8 cenas testadas
Performance Analysis of WebRTC-based Video Streaming over Power Constrained Platforms
This work analyses the use of the WebRTC framework on resource-constrained platforms. WebRTC is a consolidated solution for real-time video streaming, and it is an appealing solution in a wide range of application scenarios. We focus our attention on those in which power consumption, size and weight are of paramount importance because of size, weight and power requirements, such as the use case of unmanned aerial vehicles delivering real-time video streams overWebRTC to peers on the ground. The testbed described in this work shows that the power consumption can be reduced by changing WebRTC default settings while maintaining comparable video quality
Health-5G: A Mixed Reality-Based System for Remote Medical Assistance in Emergency Situations
Mixed reality is the combination of virtual and augmented reality to interactively and believably merge physical and computer-generated environments. This paper discusses the design of Health5G, a scalable mixed reality-based system that facilitates and supports emergency response by medical emergency teams. Health-5G is supported by a distributed architecture divided into four interrelated applications responsible for advanced computer-human interaction, effective real-time videoconference, medical device integration, and communication infrastructure, respectively. The mixed reality layer is provided by the headset Microsoft Hololens 2™. Health-5G is based on scenarios in which emergency personnel wear mixed reality glasses that can transmit audio, video, and data streams bidirectionally over a 5G network to medical specialists stationed in a hospital at any distance. Thanks to Health-5G, the specialist will be able to access the emergency team’s point of view at any time and provide verbal and visual instructions, including gestures and positioning of graphical markers in 3D space. In this way, emergency personnel can provide the best possible care to the patient without having to wait for them to arrive at the hospital, saving a lot of time in scenarios where every second can make a difference. Health-5G also addresses the integration of medical devices and the collection of the patient’s medical data in a scalable way through optical character recognition. A case study is discussed where Health-5G is used to attend a patient in the street suffering from syncope due to third-degree atrioventricular block. Latency and performance tests over a 5G network are also discussed. To the best of our knowledge, there is no comprehensive solution in the literature that provides all the capabilities offered by Health-5G in terms of functionality and advanced interaction mechanisms within the context of remote, immersive support in emergency situations
Hybrid client-server and P2P network for web-based collaborative 3D design
National audienceOur proposed research project is to enable 3D distributed visualization and manipulation involving collaborative effort through the use of web-based technologies. Our project resulted from a wide collaborative application research fields: Computer Aided Design (CAD), Building Information Modeling (BIM) or Product Life Cycle Management (PLM) where design tasks are often performed in teams and need a fluent communication system. The system allows distributed remote assembling in 3D scenes with real-time updates for the users. This paper covers this feature using hybrid networking solution: a client-server architecture (REST) for 3D rendering (WebGL) and data persistence (NoSQL) associated to an automatically built peer-to-peer (P2P) mesh for real-time communication between the clients (WebRTC). The approach is demonstrated through the development of a web-platform prototype focusing on the easy manipulation, fine rendering and light update messages for all participating users. We provide an architecture and a prototype to enable users to design in 3D together in real time with the benefits of web based online collaboration
Media streams allocation and load patterns for a WebRTC cloud architecture
Web Real-Time Communication (WebRTC) is seeing a rapid rise in adoption footprint. This standard provides an audio/video platform-agnostic communications framework for the Web build-in right in the browser. The complex technology stack of a full implementation of the standard is vast and includes elements of various computational disciplines like: content delivery, audio/video processing, media transport and quality of experience control, for both P2P and Cloud relayed communications. To the best of our knowledge, no previous study examines the impact of Cloud back-end load and media quality at production scale for a media stream processing application, as well as load mitigation for Cloud media Selective Forwarding Units. The contribution of this work is the analysis and exploitation of server workload (predictable session size, strong periodical load patterns) and media bit rate patterns that are derived from real user traffic (toward our test environment), over an extended period of time. Additionally, a simple and effective load balancing scheme is discussed to fairly distribute big sessions over multiple servers by exploiting the discovered patterns of stable session sizes and server load predictability. A Cloud simulation environment was built to compare the performance of the algorithm with other load allocation policies. This work is a basis for more advanced resource allocation algorithms and media Service Level Objectives (SLO) spanning multiple Cloud entities.Peer ReviewedPostprint (author's final draft
Cloud-edge hybrid applications
Many modern applications are designed to provide interactions among users, including multi-
user games, social networks and collaborative tools. Users expect application response time to
be in the order of milliseconds, to foster interaction and interactivity.
The design of these applications typically adopts a client-server model, where all interac-
tions are mediated by a centralized component. This approach introduces availability and fault-
tolerance issues, which can be mitigated by replicating the server component, and even relying on
geo-replicated solutions in cloud computing infrastructures. Even in this case, the client-server
communication model leads to unnecessary latency penalties for geographically close clients and
high operational costs for the application provider.
This dissertation proposes a cloud-edge hybrid model with secure and ecient propagation
and consistency mechanisms. This model combines client-side replication and client-to-client
propagation for providing low latency and minimizing the dependency on the server infras-
tructure, fostering availability and fault tolerance. To realize this model, this works makes the
following key contributions.
First, the cloud-edge hybrid model is materialized by a system design where clients maintain
replicas of the data and synchronize in a peer-to-peer fashion, and servers are used to assist
clients’ operation. We study how to bring most of the application logic to the client-side, us-
ing the centralized service primarily for durability, access control, discovery, and overcoming
internetwork limitations.
Second, we dene protocols for weakly consistent data replication, including a novel CRDT
model (∆-CRDTs). We provide a study on partial replication, exploring the challenges and
fundamental limitations in providing causal consistency, and the diculty in supporting client-
side replicas due to their ephemeral nature.
Third, we study how client misbehaviour can impact the guarantees of causal consistency.
We propose new secure weak consistency models for insecure settings, and algorithms to enforce
such consistency models.
The experimental evaluation of our contributions have shown their specic benets and
limitations compared with the state-of-the-art. In general, the cloud-edge hybrid model leads to
faster application response times, lower client-to-client latency, higher system scalability as fewer clients need to connect to servers at the same time, the possibility to work oine or disconnected
from the server, and reduced server bandwidth usage.
In summary, we propose a hybrid of cloud-and-edge which provides lower user-to-user la-
tency, availability under server disconnections, and improved server scalability – while being
ecient, reliable, and secure.Muitas aplicações modernas são criadas para fornecer interações entre utilizadores, incluindo
jogos multiutilizador, redes sociais e ferramentas colaborativas. Os utilizadores esperam que o
tempo de resposta nas aplicações seja da ordem de milissegundos, promovendo a interação e
interatividade.
A arquitetura dessas aplicações normalmente adota um modelo cliente-servidor, onde todas as
interações são mediadas por um componente centralizado. Essa abordagem apresenta problemas
de disponibilidade e tolerância a falhas, que podem ser mitigadas com replicação no componente
do servidor, até com a utilização de soluções replicadas geogracamente em infraestruturas de
computação na nuvem. Mesmo neste caso, o modelo de comunicação cliente-servidor leva a
penalidades de latência desnecessárias para clientes geogracamente próximos e altos custos
operacionais para o provedor das aplicações.
Esta dissertação propõe um modelo híbrido cloud-edge com mecanismos seguros e ecientes
de propagação e consistência. Esse modelo combina replicação do lado do cliente e propagação
de cliente para cliente para fornecer baixa latência e minimizar a dependência na infraestrutura
do servidor, promovendo a disponibilidade e tolerância a falhas. Para realizar este modelo, este
trabalho faz as seguintes contribuições principais.
Primeiro, o modelo híbrido cloud-edge é materializado por uma arquitetura do sistema em
que os clientes mantêm réplicas dos dados e sincronizam de maneira ponto a ponto e onde os
servidores são usados para auxiliar na operação dos clientes. Estudamos como trazer a maior
parte da lógica das aplicações para o lado do cliente, usando o serviço centralizado principalmente
para durabilidade, controlo de acesso, descoberta e superação das limitações inter-rede.
Em segundo lugar, denimos protocolos para replicação de dados fracamente consistentes,
incluindo um novo modelo de CRDTs (∆-CRDTs). Fornecemos um estudo sobre replicação parcial,
explorando os desaos e limitações fundamentais em fornecer consistência causal e a diculdade
em suportar réplicas do lado do cliente devido à sua natureza efémera.
Terceiro, estudamos como o mau comportamento da parte do cliente pode afetar as garantias
da consistência causal. Propomos novos modelos seguros de consistência fraca para congurações
inseguras e algoritmos para impor tais modelos de consistência.
A avaliação experimental das nossas contribuições mostrou os benefícios e limitações em comparação com o estado da arte. Em geral, o modelo híbrido cloud-edge leva a tempos de resposta
nas aplicações mais rápidos, a uma menor latência de cliente para cliente e à possibilidade de
trabalhar oine ou desconectado do servidor. Adicionalmente, obtemos uma maior escalabilidade
do sistema, visto que menos clientes precisam de estar conectados aos servidores ao mesmo tempo
e devido à redução na utilização da largura de banda no servidor.
Em resumo, propomos um modelo híbrido entre a orla (edge) e a nuvem (cloud) que fornece
menor latência entre utilizadores, disponibilidade durante desconexões do servidor e uma melhor
escalabilidade do servidor – ao mesmo tempo que é eciente, conável e seguro
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