144 research outputs found

    Data Connectivity and Smart Group Formation in Wi-Fi Direct Multi-group Networks

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    Users of Device-to-Device (D2D) communication need efficient content discovery mechanisms to steer their requests toward the node in their neighborhood that is most likely to satisfy them. The problem is further compounded by the lack of a central coordination entity as well as by the inherent mobility of devices, which leads to volatile topologies. In this paper, we first discuss group-based communication among non-rooted Android devices using Wi-Fi Direct, a protocol recently standardized by the Wi-Fi Alliance. We propose intra- and inter-group communication methodologies, which we validate through a simple testbed where content-centric routing is used. Next, we address the autonomous formation of groups with the goal of achieving efficient device resource utilization as well as full connectivity. Finally, we evaluate the performance of our group formation procedure both in simulation and in a real testbed involving Android devices in different topologies

    Novel framework using dynamic passphrase towards secure and energy-efficient communication in MANET

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    At Mobile Adhoc Network (MANET) has been long-researched topic in adhoc network owing to the associated advantages in its cost-effective application as well as consistent loophopes owing to its inherent charecteristics. This manuscript draws a relationship between the energy factor and security factor which has not been emphasized in any existing studies much. Review of existing security approaches shows that they are highly attack specific, uses complex encryption, and overlooks the involvement of energy factor in it. Therefore, the proposed system introduces a novel mechanism where security tokens and passphrases are utilized in order to offer better security. The proposed system also introduces the usage of an agent node which communications with mobile nodes using group-based communication system thereby ensuring reduced computational effort of mobile nodes towards establishing secured communication. The outcome shows proposed system offers better outcome in contrast to existing system

    IR-CP-ABE: Identity Revocable Ciphertext-Policy Attribute-Based Encryption for Flexible Secure Group-Based Communication

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    Ciphertext-Policy Attribute-Based Encryp- tion (CP-ABE) is an access control mechanism over encrypted data and well suited for secure group-based communication. However, it also suffers from the fol- lowing problem, i.e., it is impossible to build all de- sired groups. For example, if two group members have exactly the same attributes, how to construct a group including only one of the two members? Obviously, at- tributes alone cannot distinguish these two members, therefore existing CP-ABE solutions do not work. To address this issue, in this paper, we present a new CP-ABE scheme (called IR-CP-ABE) that incorporates an Identity-based Revocation capability. With IR-CP-ABE, an access policy will be constructed by not only group members’ attributes but also their identities. To build a group, first, build a candidate group based on all de- sired group members’ attributes; second, remove unde- sired members by revoking their identities. By evaluat- ing the security and efficiency of a proposed construc- tion, we show that the IR-CP-ABE scheme is secure and efficient for practical applications

    Mobile-awareness:designing for mobile interactive systems

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    In recent years, we have witnessed a significant increase in the availability and adoption of mobile devices with wireless communications capabilities. Such devices can be used as the end-system in network-based (single or multi

    A metaobject architecture for fault-tolerant distributed systems : the FRIENDS approach

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    The FRIENDS system developed at LAAS-CNRS is a metalevel architecture providing libraries of metaobjects for fault tolerance, secure communication, and group-based distributed applications. The use of metaobjects provides a nice separation of concerns between mechanisms and applications. Metaobjects can be used transparently by applications and can be composed according to the needs of a given application, a given architecture, and its underlying properties. In FRIENDS, metaobjects are used recursively to add new properties to applications. They are designed using an object oriented design method and implemented on top of basic system services. This paper describes the FRIENDS software-based architecture, the object-oriented development of metaobjects, the experiments that we have done, and summarizes the advantages and drawbacks of a metaobject approach for building fault-tolerant system

    Share and multiply: modeling communication and generated traffic in private WhatsApp groups

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    Group-based communication is a highly popular communication paradigm, which is especially prominent in mobile instant messaging (MIM) applications, such as WhatsApp. Chat groups in MIM applications facilitate the sharing of various types of messages (e.g., text, voice, image, video) among a large number of participants. As each message has to be transmitted to every other member of the group, which multiplies the traffic, this has a massive impact on the underlying communication networks. However, most chat groups are private and network operators cannot obtain deep insights into MIM communication via network measurements due to end-to-end encryption. Thus, the generation of traffic is not well understood, given that it depends on sizes of communication groups, speed of communication, and exchanged message types. In this work, we provide a huge data set of 5,956 private WhatsApp chat histories, which contains over 76 million messages from more than 117,000 users. We describe and model the properties of chat groups and users, and the communication within these chat groups, which gives unprecedented insights into private MIM communication. In addition, we conduct exemplary measurements for the most popular message types, which empower the provided models to estimate the traffic over time in a chat group

    WhatsApp Group Sebagai Ruang Percakapan Pastoral di Masa Pandemi Covid-19

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    Abstract. This study discussed pastoral activities during the Covid-19 pandemic through WhatsApp group as pastoral space. It investigated group-based communication in WhatsApp based on a survey toward the Catholic Family Ministry in the Diocese of Malang. The result was that the conversations in the WhatsApp group in form of reflections, shared links, inspiration, prayers, and information showed that the ecclesiastical community has the courage to be present and involved in human life today. Conversations in WhatsApp groups taught and shared Christian values that opposed to individualism, consumerism, and hedonism, as well as to be a space to proclaim the values of Christian life, namely: love, care, fellowship, justice, peace, solidarity, sharing and living hopefully to God the source of life.Abstrak. Penelitian ini mendiskusikan aktivitas pastoral selama masa pandemi Covid-19 yang menggunakan WhatsApp group sebagai ruang pastoral. Metode penelitian yang digunakan adalah metode survey. Studi ini mensurvey percakapan yang terjadi di Whatsapp group komunitas Catholic Family Ministry Keuskupan Malang. Hasil penelitian menunjukkan bahwa percakapan dalam WhatsApp group berupa renungan, share link, inspirasi, doa, dan informasi menunjukkan bahwa komunitas gerejawi berani hadir dan terlibat dalam hidup manusia pada masa kini. Percakapan dalam WhatsApp group menampilkan nilai Kristiani yang melawan individualisme, konsumerisme dan hedonism di ruang digital, dan sebaliknya, menjadi ruang menyuarakan nilai-nilai kehidupan Kristiani, yaitu: cinta kasih, perhatian, persekutuan, keadilan, perdamaian, solidaritas, berbagi serta hidup penuh pengharapan kepada Allah Sang Sumber Hidup

    Architecture and evaluation of a unified V2V and V2I communication system based on cellular networks

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    Vehicle communications are becoming the cornerstone in the future vehicle equipment. More specifically, vehicle to vehicle communications (V2V) are the main object of researching nowadays, because vehicle to infrastructure (V2I) approximations are already being developed as commercial solutions. Cellular networks (CN) are usually applied in V2I solutions, whereas ad hoc networks are practically the only technology considered in V2V communications. Due to fact that CN are currently a reality and the operators are continuously improving the network, this communication technology could be considered as a candidate to deal with V2V necessities as well. The present paper defends the applicability of CN in the V2V field, and presents a novel communication paradigm for vehicles which unifies both V2V and V2I paradigms into one system. A peer to peer network technology has been used over the CN basis to create a group-based communication infrastructure which enables the message propagation among vehicles and between the car and the road side infrastructure. The architecture has been implemented in both hardware and software terms, and multitude of field tests have been carried out, whose main performance results are shown in the paper.The authors would like to thank the Spanish Ministerio the Educacion y Ciencia for sponsoring the research activities under the grant AP2005-1437, in frames of the FPU program, and to the financial support given by the European Spatial Agency (ESA) under the GIROADS 332599 project. Special thanks as well to the Spanish Ministerio the Fomento for its continuous support in vehicular researching
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