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A new time dissemination and synchronization service over public switched telephone network (PSTN) has been established at CSIR-NPL. The time synchronization accuracy achieved using is this service is ± 10 ms. The measurement of round trip delay and its cancellation in the final time code sent to the receiver has been implemented in this service. In this paper, the technical details of this service...
We consider the case of spreadsheet based workgroup collaboration, in which users cooperate through spreadsheets. While spreadsheet exchange through email and shared directories is still the most common way to share data, spreadsheet sharing in the Cloud is rapidly spreading, leveraging the evolution of office tools toward delocalized system over the Cloud. In this paper we observe that spreadsheet...
Due to the increasing dependency of critical infrastructure on synchronized clocks, network time synchronization protocols have become an attractive target for attackers. We identify data origin authentication as the key security objective and therefore conduct a comprehensive, theoretical evaluation of data origin authentication schemes from different application fields with regard to their applicability...
High quality of the provided communication services can be reached by package networks by the organization of network synchronization of the time scales (TS). The report summarizes the experience of comparing the TS of the leading watches of the corporate telecommunication network with the state time scale - UTC (SU). The methods of realization of checking of a time scale and methods of distribution...
Rehabilitation robotic systems may afford better care and telerehabilitation may extend the use and benefits of robotic therapy to the home. Data transmissions over distance are bound by intrinsic communication delays which can be significant enough to deem the activity unfeasible. Here we describe an approach that combines unilateral robotic telerehabilitation and serious games. This approach has...
Device synchronization is a new technology integrated into the cloud which has seen widespread implementation from major cloud vendors but has not been spared of attacks by MITC attacks directed towards cloud synchronization achieved via a myriad of attack vectors. These target the synchronization token which lacks authenticity validation of the token bearer. We explore MITC in Linux systems by partitioning...
Smartphones have become the de-facto capture devices for everyday photography. Unlike traditional digital cameras, smartphones are versatile devices with auxiliary sensors, processing power, and networking capabilities. In this work, we harness the communication capabilities of smartphones and present a synchronous/co-ordinated multi-camera capture system. Synchronous capture is important for many...
Middleboxes (MBs) are ubiquitous in modern data centre (DC) due to their crucial role in implementing network security, management and optimisation. In order to meet network policy's requirement on correct traversal of an ordered sequence of MBs, network administrators rely on static policy based routing or VLAN stitching to steer traffic flows. However, dynamic virtual server migration in virtual...
Model driven engineering allows many stakeholders to contribute their expertise to the system description. This practice enables agility but implies consistency maintenance issues between different system models. Incremental model transformations (IMT) are used to synchronize different artifacts contributed by the stakeholders. IMTs detect changes on the source model and execute change rules to propagate...
In cloud environment, client user credential protection is a critical security capability that is target of adversarial attacks, especially, in cloud file synchronization applications. Among the various adversarial attacks, MITC (Man in the Cloud) attack on commercial cloud storage applications has emerged as a critical threat because it is easy to launch and hard to detect. In this paper, we propose...
Coded caching is a technique that promises huge reductions in network traffic in content-delivery networks. However, the original formulation and several subsequent contributions in the area, assume that the file requests from the users are synchronized, i.e., they arrive at the server at the same time. In this work we formulate and study the coded caching problem when the file requests from the users...
Deduplication finds and removes long-range data duplicates. It is commonly used in cloud and enterprise server settings and has been successfully applied to primary, backup, and archival storage. Despite its practical importance as a source-coding technique, its analysis from the point of view of information theory is missing. This paper provides such an information-theoretic analysis of data deduplication...
Radio Frequency Identification (RFID) makes it a supporting technology for the Internet of things (IoT). While RFID has been widely used and developed rapidly, its security and privacy issues cannot be ignored. With the development of cloud computing, cloud based RFID system has become a new solution. Protecting the security of RFID system in cloud environment is particularly important. Not verifying...
We present Timestamp Order Preserving (TOP), a replicated state machine (RSM) protocol that exploits the synchrony of networks to provide high performance. TOP uses physical timestamp of synchronized clock as a consistent total order to achieve consensus. It keeps estimating the bounds of network latency and offset of synchronized clock to deduce the commit time for each operation. It adopts speculative...
In this paper we present a new approach to implementing causal consistency in geo-replicated data stores, which we call Optimistic Causal Consistency (OCC). The optimism in our approach lies in that updates from a remote data center are immediately made visible in the local data center, without checking if their causal dependencies have been received. Servers perform the dependency check needed to...
Cloud storage services, such as Dropbox, iCloud Drive, Google Drive, and Microsoft OneDrive, have greatly facilitated users’ synchronizing files across heterogeneous devices. Among them, Dropbox-like services are particularly beneficial owing to the delta sync functionality that strives towards greater network-level efficiency. However, when delta sync trades computation overhead for network-traffic...
With the increasing popularity of serving and storing data in multiple data centers, we investigate the efficiency of majority quorum-based data consistency algorithms under this scenario. Because of the failure-prone nature of distributed storage systems, majority quorum-based data consistency algorithms become one of the most widely adopted approaches. In this paper, we propose the MeteorShower...
Caching plays an important role in many domains, as it can lead to important performance improvements. A key-value based caching system typically stores the results of popular queries in efficient storage locations. While caching enjoys widespread usage in the context of dynamic web applications, most mainstream caching systems store static binary items, which makes them impractical for many real-world...
Converting audio signal to packet stream and propagating through wireless local area network (Wi-Fi technology) to loud speakers that may be located at different rooms will be a popular scenario of multimedia applications. Since the packets received by separate speakers varied with the transmission paths and environment to them, this made the playable contents different from one speaker to another...
This paper proposes an event detection module for distributed denial of service (DDoS) attacks on Internet of Things (IoT). Different from existing detection modules using knowledge-based filtering, the proposed module focuses on the system behavior under DDoS attacks and detects it utilizing information obtained from NTP used in synchronization service. We conducted demonstration experiments with...
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