90,662 research outputs found

    Distributed Object Medical Imaging Model

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    Abstract- Digital medical informatics and images are commonly used in hospitals today,. Because of the interrelatedness of the radiology department and other departments, especially the intensive care unit and emergency department, the transmission and sharing of medical images has become a critical issue. Our research group has developed a Java-based Distributed Object Medical Imaging Model(DOMIM) to facilitate the rapid development and deployment of medical imaging applications in a distributed environment that can be shared and used by related departments and mobile physiciansDOMIM is a unique suite of multimedia telemedicine applications developed for the use by medical related organizations. The applications support realtime patients’ data, image files, audio and video diagnosis annotation exchanges. The DOMIM enables joint collaboration between radiologists and physicians while they are at distant geographical locations. The DOMIM environment consists of heterogeneous, autonomous, and legacy resources. The Common Object Request Broker Architecture (CORBA), Java Database Connectivity (JDBC), and Java language provide the capability to combine the DOMIM resources into an integrated, interoperable, and scalable system. The underneath technology, including IDL ORB, Event Service, IIOP JDBC/ODBC, legacy system wrapping and Java implementation are explored. This paper explores a distributed collaborative CORBA/JDBC based framework that will enhance medical information management requirements and development. It encompasses a new paradigm for the delivery of health services that requires process reengineering, cultural changes, as well as organizational changes

    Tarmo: A Framework for Parallelized Bounded Model Checking

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    This paper investigates approaches to parallelizing Bounded Model Checking (BMC) for shared memory environments as well as for clusters of workstations. We present a generic framework for parallelized BMC named Tarmo. Our framework can be used with any incremental SAT encoding for BMC but for the results in this paper we use only the current state-of-the-art encoding for full PLTL. Using this encoding allows us to check both safety and liveness properties, contrary to an earlier work on distributing BMC that is limited to safety properties only. Despite our focus on BMC after it has been translated to SAT, existing distributed SAT solvers are not well suited for our application. This is because solving a BMC problem is not solving a set of independent SAT instances but rather involves solving multiple related SAT instances, encoded incrementally, where the satisfiability of each instance corresponds to the existence of a counterexample of a specific length. Our framework includes a generic architecture for a shared clause database that allows easy clause sharing between SAT solver threads solving various such instances. We present extensive experimental results obtained with multiple variants of our Tarmo implementation. Our shared memory variants have a significantly better performance than conventional single threaded approaches, which is a result that many users can benefit from as multi-core and multi-processor technology is widely available. Furthermore we demonstrate that our framework can be deployed in a typical cluster of workstations, where several multi-core machines are connected by a network

    CloudJet4BigData: Streamlining Big Data via an Accelerated Socket Interface

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    Big data needs to feed users with fresh processing results and cloud platforms can be used to speed up big data applications. This paper describes a new data communication protocol (CloudJet) for long distance and large volume big data accessing operations to alleviate the large latencies encountered in sharing big data resources in the clouds. It encapsulates a dynamic multi-stream/multi-path engine at the socket level, which conforms to Portable Operating System Interface (POSIX) and thereby can accelerate any POSIX-compatible applications across IP based networks. It was demonstrated that CloudJet accelerates typical big data applications such as very large database (VLDB), data mining, media streaming and office applications by up to tenfold in real-world tests

    Investigating impacts of environmental factors on the cycling behavior of bicycle-sharing users

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    As it is widely accepted, cycling tends to produce health benefits and reduce air pollution. Policymakers encourage people to use bikes by improving cycling facilities as well as developing bicycle-sharing systems (BSS). It is increasingly interesting to investigate how environmental factors influence the cycling behavior of users of bicycle-sharing systems, as users of bicycle-sharing systems tend to be different from regular cyclists. Although earlier studies have examined effects of safety and convenience on the cycling behavior of regular riders, they rarely explored effects of safety and convenience on the cycling behavior of BSS riders. Therefore, in this study, we aimed to investigate how road safety, convenience, and public safety affect the cycling behavior of BSS riders by controlling for other environmental factors. Specifically, in this study, we investigated the impacts of environmental characteristics, including population density, employment density, land use mix, accessibility to point-of-interests (schools, shops, parks and gyms), road infrastructure, public transit accessibility, road safety, convenience, and public safety on the usage of BSS. Additionally, for a more accurate measure of public transit accessibility, road safety, convenience, and public safety, we used spatiotemporally varying measurements instead of spatially varying measurements, which have been widely used in earlier studies. We conducted an empirical investigation in Chicago with cycling data from a BSS called Divvy. In this study, we particularly attempted to answer the following questions: (1) how traffic accidents and congestion influence the usage of BSS; (2) how violent crime influences the usage of BSS; and (3) how public transit accessibility influences the usage of BSS. Moreover, we tried to offer implications for policies aiming to increase the usage of BSS or for the site selection of new docking stations. Empirical results demonstrate that density of bicycle lanes, public transit accessibility, and public safety influence the usage of BSS, which provides answers for our research questions. Empirical results also suggest policy implications that improving bicycle facilities and reducing the rate of violent crime rates tend to increase the usage of BSS. Moreover, some environmental factors could be considered in selecting a site for a new docking station

    SLA-Based Performance Tuning Techniques for Cloud Databases

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    Today, cloud databases are widely used in many applications. The pay-per-use model of cloud databases enables on-demand access to reliable and configurable services (CPU, storage, networks, and software) that can be quickly provisioned and released with minimal management and cost for different categories of users (also called tenants). There is no need for users to set up the infrastructure or buy the software. Users without related technical background can easily manage the cloud database through the console provided by service providers, and they just need to pay to the cloud service provider only for the services they use through a service level agreement (SLA) that specifies the performance requirements and the pricing associated with the leased services. However, due to the resource sharing structure of the cloud, different tenants’ workloads compete for computing resource. This will affect tenants’ performance, especially during the workload peak time. So it is important for cloud database service providers to develop techniques that can tune the database in order to re-guarantee the SLA when a tenant’s SLA is violated. In this dissertation, two algorithms are presented in order to improve the cloud database’s performance in a multi-tenancy environment. The first algorithm is a memory buffer management algorithm called SLA-LRU and the second algorithm is a vertical database partitioning algorithm called AutoClustC. SLA-LRU takes SLA, buffer page’s frequency, buffer page’s recency, and buffer page’s value into account in order to perform buffer page replacement. The value of a buffer page represents the removal cost of this page and can be computed using the corresponding tenant’s SLA penalty function. Only the buffer pages whose tenants have the least SLA penalty cost increment will be considered by the SLA-LRU algorithm when a buffer page replacement action is taken place. AutoClustC estimates the tuning cost for resource provisioning and database partitioning, then selects the most cost saving tuning method to tune the database. If database partitioning is selected, the algorithm will use data mining to identify the database partitions accessed frequently together and will re-partition the database accordingly. The algorithm will then distribute the resulting partitions to the standby physical machines (PMs) that have the least overload score computed based on both the PMs’ communication cost and overload status. Comprehensive experiments were conducted in order to study the performance of SLA-LRU and AutoClustC using the TPC-H benchmark on both the public cloud (Amazon RDS) and private cloud. The experiment results show that SLA-LRU gives the best overall performance in terms of query response time and SLA penalty cost improvement ratio, compared to the existing memory buffer management algorithms; and AutoClustC is capable of identifying the most cost-saving cloud database tuning method with high accuracy from resource provisioning and database partitioning, and performing database re-partitioning dynamically to provide better query response time than the current partitioning configuration

    Rising waters : integrating national datasets for the visualisation of diminishing spatial entities

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    Preparing for the potential changes wrought by climate change can be grounded in commonly integrated real data. Efforts by various countries to prepare for such potentialities have resulted in a stepped- approach to data management and integration. Small island states experience an added burden through data limitations, disparate datasets and data hoarding. This paper reviews the processes employed in Malta that target a spatio-temporal analysis of current and future climate change scenarios aimed at integrating environmental, spatial planning and social data in line with the transposition of the Aarhus Convention, the INSPIRE Directive (Infrastructure for Spatial Information in the European Community) and the SEIS (Shared Environmental Information System) initiative. The study analyses potential physical and social aspects that will be impacted by sea-level rise in the Maltese islands. Scenarios include the analysis of areas that will be inundated, the methodology employed to carry out the analysis, and the relative impacts on land use and environmental, infrastructural and population loss. Spatial information systems and 3D outputs illustrate outcome scenarios.peer-reviewe
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