Page 353 - From Smart Grid to Internet of Energy
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Big data, privacy and security in smart grids Chapter  8 317


             The IoT based device number is expected to reach up to billions that can trans-
             mit instant data. In addition to data volumes, variety and structures of transmit-
             ted data will be heterogeneous depending IoT device types, structures, and
             vendors. The IoT devices are foreseen to be converted from simple sensors
             to much more sophisticated systems which have their own processors and stor-
             age devices. Therefore, malfunction of such systems may cause to severe fail-
             ures which cannot be handled with basic troubleshooting methods. On the other
             hand, the updating frequency of data acquisition is another challenging topic in
             IoT Big Data operations. The substantial part of IoT devices are assumed to
             transmit measurement and control signals with higher frequencies while some
             others such as cars and electric vehicles will generate data stacks at lower
             frequencies [15].
                The IoT devices and sensors comprise entity definitions as shown in Fig. 8.3.
             The sensor-based communication infrastructure provides connection between
             devices and applications at IoT service layer.
                The third-party applications are also integrated to IoT ecosystem over ser-
             vices interface. The interfaces are managed by application program interface
             (API) based software which provide authentication and security controls
             according to standards. The data layer applications are operated regarding to
             subscriber data and enable users to store data. The inherited data stacks come
             from several sources and devices and collected by Data and Protocol Mediator
             that is responsible for acquiring provided data of IoT based devices and other
             sources. The data and protocol mediator layer convert control demands and
             requests to low level IoT protocols. The IoT big data storage layer enables mas-
             sive and high volume IoT data acquisition for storage processes, and it presents
             data for analytics and research purposes. The IoT big data processing section
             allows to use hardware and analytics tools to generate data reports and intelli-
             gence outputs.
                The data storage capability of IoT devices will define flexibility of Big Data
             applications since it will allow or prevent data derivation from intelligent
             devices for smart monitoring and smart control operations. Another significant
             challenge is related with privacy issues against intrusions and violations. Once
             the data which is generated by IoT devices is stored in a Big Data analytic sys-
             tem, and presented to use for third parties, it forces operators and service pro-
             viders to improve system security and authentication controls. The functional
             sections and layers of presented IoT Big Data architecture enable to obtain
             IoT and Big Data services in a wide range. These services include management
             functions, direct data control features, external data acquisition, establishing
             connection between IoT data platforms and devices, and delivery of IoT based
             data stacks. The Big Data analysis is based on data acquisition methods and data
             access opportunities. The function provides data storage feature such as storing
             the small scale data to hard disk drives or multiple disk usage depending the
             increased data volumes. The stored data stack should be planned by considering
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