Future Cities Data and Services API

Abstract

Due to the continued growth of the number of people living in urban areas (in 2010 75% of the European Union population lived in cities and this number is expected to increase to 85% by 2050) and its development, the terms Smart Cities, that refers to cities that implement solutions that allow them significant qualitative and quantitative improvements in productivity and in the qualityofpeople'slife,andInternetofThings,whichistheconnectionof"things-suchassensors - to the Internet, are quite important in this context. Therefore, the Future Cities Project appeared with the objective of turning the city of Porto into a smart city and a living lab at urban scale. Thus, two sensor platforms, SenseMyCity and UrbanSense,weredeployedalloverthecity. Theseplatformscolectgeo-indexeddatathroughthe several sensors available in a smartphone and atmospheric data, noise through stationary sensors. Due to the appearance of these smart cities, more and more middlewares to develop services andapplicationsforthesestartedtoappear,andthereforethereistheneedtohavequantitativeand qualitative comparisons betweenthem, describing which oneis the best in each situation andwhy should we choose one or another. This quantitative analysis is aimed at generating a performance benchmark and focuses on three different scenarios: data flux (publish/subscribe model), request/response and the provision of a dataset, and each scenario has different perfomance metrics, tailored for each one. In the first one, the performance metrics used are the time to publish the data, the time to receive the data's subscriptions, the amount of bytes used to publish, throughput, the variable size relative to the sensor readings, among others. In the second one, the response time, throughput, amount of bytes used, among others will be evaluated. At last, in the third one there is not much to evaluate in terms of performance, it is more focused on software engineering limitations of each technology to hold thousands of data. The qualitative analysis is focused on the evaluation of all the middlewares in terms of nonquantifiable metrics such as usability, support to fix bugs, API documentation, viability of each technologyin eachscenarioaccordingtothesoftwareengineeringlimitationsofeachone, among others. The middlewares used in this analysis are plain REST services, ETSI M2M, FIWARE and CitySDK, and each one will be evaluted in all scenarios if it is applicable.