6,508 research outputs found
Generation of initial molecular dynamics configurations in arbitrary geometries and in parallel
A computational pre-processing tool for generating initial configurations of molecules for molecular dynamics simulations in geometries described by a mesh of unstructured arbitrary polyhedra is described. The mesh is divided into separate zones and each can be filled with a single crystal lattice of atoms. Each zone is filled by creating an expanding cube of crystal unit cells, initiated from an anchor point for the lattice. Each unit cell places the appropriate atoms for the user-specified crystal structure and orientation. The cube expands until the entire zone is filled with the lattice; zones with concave and disconnected volumes may be filled. When the mesh is spatially decomposed into portions for distributed parallel processing, each portion may be filled independently, meaning that the entire molecular system never needs to fit onto a single processor, allowing very large systems to be created. The computational time required to fill a zone with molecules scales linearly with the number of cells in the zone for a fixed number of molecules, and better than linearly with the number of molecules for a fixed number of mesh cells. Our tool, molConfig, has been implemented in the open source C++ code OpenFOAM
Enhanced Topology Aware Routing for WSN
In this paper Enhanced Topology Aware Routing (ETAR) is proposed for point to point routing in wireless sensor network. Each node is characterized by a coordinate vector consisting of the shortest path hop distances to a subset of nodes, named anchors. The ETAR algorithm efficiently maps a network topology into a low-dimensional virtual coordinate space where hop distances between pairwise nodes are preserved. It assist greedy forwarding to find the right neighbor that is one hop closer to the destination by eliminating the local minimum problem and achieve high success ratio of packet delivery and throughput without location informatio
Trusted Computing and Secure Virtualization in Cloud Computing
Large-scale deployment and use of cloud computing in industry
is accompanied and in the same time hampered by concerns regarding protection of
data handled by cloud computing providers. One of the consequences of moving
data processing and storage off company premises is that organizations have
less control over their infrastructure. As a result, cloud service (CS) clients
must trust that the CS provider is able to protect their data and
infrastructure from both external and internal attacks. Currently however, such
trust can only rely on organizational processes declared by the CS
provider and can not be remotely verified and validated by an external party.
Enabling the CS client to verify the integrity of the host where the
virtual machine instance will run, as well as to ensure that the virtual
machine image has not been tampered with, are some steps towards building
trust in the CS provider. Having the tools to perform such
verifications prior to the launch of the VM instance allows the CS
clients to decide in runtime whether certain data should be stored- or calculations
should be made on the VM instance offered by the CS provider.
This thesis combines three components -- trusted computing, virtualization technology
and cloud computing platforms -- to address issues of trust and
security in public cloud computing environments. Of the three components,
virtualization technology has had the longest evolution and is a cornerstone
for the realization of cloud computing. Trusted computing is a recent
industry initiative that aims to implement the root of trust in a hardware
component, the trusted platform module. The initiative has been formalized
in a set of specifications and is currently at version 1.2. Cloud computing
platforms pool virtualized computing, storage and network resources in
order to serve a large number of customers customers that use a multi-tenant
multiplexing model to offer on-demand self-service over broad network.
Open source cloud computing platforms are, similar to trusted computing, a
fairly recent technology in active development.
The issue of trust in public cloud environments is addressed
by examining the state of the art within cloud computing security and
subsequently addressing the issues of establishing trust in the launch of a
generic virtual machine in a public cloud environment. As a result, the thesis
proposes a trusted launch protocol that allows CS clients
to verify and ensure the integrity of the VM instance at launch time, as
well as the integrity of the host where the VM instance is launched. The protocol
relies on the use of Trusted Platform Module (TPM) for key generation and data protection.
The TPM also plays an essential part in the integrity attestation of the
VM instance host. Along with a theoretical, platform-agnostic protocol,
the thesis also describes a detailed implementation design of the protocol
using the OpenStack cloud computing platform.
In order the verify the implementability of the proposed protocol, a prototype
implementation has built using a distributed deployment of OpenStack.
While the protocol covers only the trusted launch procedure using generic
virtual machine images, it presents a step aimed to contribute towards
the creation of a secure and trusted public cloud computing environment
Harnessing Technology: new modes of technology-enhanced learning: a case study series
This report presents the outcomes and conclusions from a series of 18 case studies exploring the innovative use of technology for learning and teaching using new modes of technology
Enhancing Safety on Construction Sites: A UWB-Based Proximity Warning System Ensuring GDPR Compliance to Prevent Collision Hazards
Construction is known as one of the most dangerous industries in terms of worker safety. Collisions due the excessive proximity of workers to moving construction vehicles are one of the leading causes of fatal and non-fatal accidents on construction sites internationally. Proximity warning systems (PWS) have been proposed in the literature as a solution to detect the risk for collision and to alert workers and equipment operators in time to prevent collisions. Although the role of sensing technologies for situational awareness has been recognised in previous studies, several factors still need to be considered. This paper describes the design of a prototype sensor-based PWS, aimed mainly at small and medium-sized construction companies, to collect real-time data directly from construction sites and to warn workers of a potential risk of collision accidents. It considers, in an integrated manner, factors such as cost of deployment, the actual nature of a construction site as an operating environment and data protection. A low-cost, ultra-wideband (UWB)-based proximity detection system has been developed that can operate with or without fixed anchors. In addition, the PWS is compliant with the General Data Protection Regulation (GDPR) of the European Union. A privacy-by-design approach has been adopted and privacy mechanisms have been used for data protection. Future work could evaluate the PWS in real operational conditions and incorporate additional factors for its further development, such as studies on the timely interpretation of data
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TECHNICAL EVALUATION OF FLOATING OFFSHORE WIND PLANTS AND INSTALLATION OPERATIONS
Offshore wind energy is witnessing remarkable growth, driven by the global shift towards sustainable and renewable energy sources. A pivotal innovation in this domain is floating offshore wind technology, which represents a transformative opportunity in harnessing wind energy from deep waters, where conventional fixed-bottom offshore wind systems face limitations due to depth constraints and escalating costs. In light of regional commitments to lower carbon emissions in energy generation, the accessibility of deep-water zones, rich in offshore wind resources, becomes increasingly critical. Despite the promising prospects, the floating offshore wind turbine (FOWT) developments present intricate challenges encompassing design, installation, and operational logistics. This study adopts a two-pronged approach, beginning with a technical review of the current state-of-the-art FOWT technology, drawing from a wide range of literature, industry reports, and guidelines. Building upon this foundation, the research introduces a simulation tool tailored for floating offshore wind deployment operations, designed to analyze and navigate the various phases of FOWT construction. The tool pre-simulates planned installations, factoring in design specifications, weather conditions, and unique location attributes. The simulation aids in task scheduling, long-term installation potential projections, and determining project pacing needs, thereby informing future FOWT and infrastructure developments. The analysis delves into the nuanced interplay of FOWT design, scale, and environmental variables, highlighting the impact of location-specific metocean patterns on bottleneck installation tasks. The resulting vii analysis provides strategic insights for enhancing FOWT technology, emphasizing innovation and standardization in addressing dynamic installation challenges. This thesis aims to increase the commercial viability and contribute to advancing FOWT projects
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