In this paper, we present an innovative framework whose objective is to allow drivers to recharge their Electric Vehicles (EVs) from the most environmentally friendly chargers using an intelligent hoarding approach. These chargers maximize renewable (e.g., solar) self-consumption, minimizing this way CO2 production and also the need for expensive stationary batteries on the electricity grid to store renewable energy that cannot be used otherwise. We model our problem as a Continuous k-Nearest Neighbor query, where the distance function is computed using Estimated Components (ECs), i.e., a query we term CkNN-EC. An EC defines a function that can have a fuzzy value based on some estimates. Specific ECs used in this work are: (i) the (available clean) power at the charger, which depends on the estimated weather; (ii) the charger availability, which depends on the estimated busy timetables that show when the charger is crowded; and (iii) the derouting cost, which is the time to reach the charger depending on estimated traffic. We devise the EcoCharge framework that combines these multiple non-conflicting objectives into an optimization task providing user-defined ranking means through an intuitive mobile GIS application. Particularly, our core algorithm uses lower and upper values derived from the ECs to recommend the top ranked EV chargers and present them through an intuitive map user interface to users. Our experimental evaluation with extensive synthetic and real traces from Germany, China, and USA along with EV charger data from Plugshare shows that EcoCharge meets the objective functions in an efficient manner, allowing continuous recomputation on the edge devices (e.g., Android Automotive OS, Android Auto or Apple Carplay).

In this demonstration paper, we present an innovative framework for sustainable Electric Vehicles (EVs) charging, dubbed EcoCharge, which utilizes an intelligent energy hoarding approach. Particularly, EcoCharge employs a Continuous k-Nearest Neighbor query, where the distance function is computed using Estimated Components (ECs) (i.e., a query we term CkNN-EC). An EC defines a function that can have a fuzzy value based on some estimates. Specific ECs used in this work are: (i) the (available clean) power at the charger, which depends on the estimated weather; (ii) the charger availability, which depends on the estimated busy timetables that show when the charger is crowded; and (iii) the derouting cost, which is the time to reach the charger depending on estimated traffic. Our framework combines these multiple non-conflicting objectives into an optimization task providing user-defined ranking means through an intuitive spatial application. The algorithm utilizes lower and upper interval values derived from ECs to recommend the top ranked EV chargers and present them through a map interface to users. We demonstrate EcoCharge using a complete prototype system developed using the Leaflet - OpenStreetMap library. In our demonstration scenario, attendees will have the opportunity to observe through mobile devices the benefits of EcoCharge by simulating its execution over various scheduled trips with real data retrieved from API requests (i.e., ECs).

Pedestrian-focused modeling of urban environments is difficult due to a lack of publicly available realistic datasets, and the time and labor-intensive manual processes required to make one, creating barriers to effective evaluation and analysis. In this paper, we introduce GIO.G, a Generator for Indoor-Outdoor Graphs, designed to address these challenges and enhance pedestrian-focused simulation in urban environments. GIO.G offers configurable parameters such as building characteristics, urban density, and foot traffic congestion levels, enabling users to explore a wide range of scenarios with precision and scalability. Through a series of scenarios, we highlight GIO.G’s unique features and showcase GIO.G’s versatility and effectiveness in generating realistic Indoor-Outdoor Graphs.

Energy efficiency has become a primary optimization objective due to the global energy crisis and high levels of CO2emissions. Climate and energy targets have been leading to a growing utilization of solar photovoltaic power generation in residential buildings. As the number of IoT devices drastically increases, their automation through an intelligent home energy management system can provide energy and peak demand savings. The planning optimization of devices can be very challenging due to the unsophisticated user-defined preference rules. Existing solutions face convergence difficulties due to the management of multiple IoT devices tackling multiobjective problems. In this paper, we propose an innovative IoT data system, coined GreenCap, which utilizes a Green Planning evolutionary algorithm for load shifting of IoT-enabled devices, considering the integration of renewable energy sources, multiple constraints, peak-demand times, and dynamic pricing. We have implemented a complete prototype system available on Raspberry Pi and linked with openHAB framework. Our experimental evaluation with extensive real traces shows that the GreenCap prototype system efficiently generates a sustainable plan obtaining high levels of user comfort 92-99% along with ≈52% of self-consumption, while reducing ≈35% of the imported energy from the grid and ≈40% of CO2emissions.

In this demonstration paper, we present an innovative IoT data platform, coined GreenCap, which utilizes a Green Planning evolutionary algorithm for load shifting of IoT-enabled devices in smart environments that feature renewable energy sources. Particularly, GreenCap deploys a hybrid genetic algorithm with domain-specific local search heuristics, which results in a Memetic Algorithm (MA) that offers users an energy efficient allocation plan of their IoT devices, based on their personal preference rules (e.g., operate AC from 10am - 1pm). Our system allocates operations in the daily time-slots considering devices’ energy bounds to minimize the imported energy from the grid, exploit self-consumption and maximize users’ comfort. We demonstrate GreenCap using a complete prototype system available on Raspberry Pi, developed in Laravel using MariaDB and linked to openHAB framework. In our demonstration scenario, attendees will be able to observe through mobile devices the benefits of GreenCap by simulating its execution with real data for one week, using pre-configured or custom rules.

Accessibility and usability have been key concerns in the design of computer interfaces through which users interact with applications and systems. Recently, chatbots have gained popularity with service providers for improvements in this area. In this paper, we present our experience in designing and implementing CAPRIO’s inclusive chatbot-based interface for pedestrian path recommendations. Our CAPRIO system provides inclusive usability by extracting user preferences in a non-intrusive dialog and using them to build a more accurate model for the user’s intent. It uses the Microsoft Bot Framework (MBF) and NLP modeling to support text and voice dialog.

The exposure to viral airborne diseases is higher in crowded and congested spaces, the COVID-19 pandemic has revealed the need of pedestrian recommendation systems that can recommend less congested paths which minimize exposure to infectious crowd diseases in general. In this paper, we introduce ASTRO-C, an extension of previous work ASTRO, which optimizes for minimum congestion. To our knowledge, ASTRO-C is the only solution to this problem of constraint-satisfying, indoor-outdoor, congestion-based path finding. Our experimental evaluation using randomly generated Indoor-Outdoor graphs with varying constraints matching various real-world scenarios, show that ASTRO-C is able to recommend paths with, on average a 0.62X reduction in average congestion, while on average, total travel time increases by 1.06X and never exceeds 1.10X compared to ASTRO.

Accessibility and usability have been key concerns in the design of computer interfaces through which users interact with an application or a system. In developing CAPRIO, our personalized path recommendation system, usability was a design principle for its interface and accessibility was central in its path-finding algorithm, which currently considers user mobility constraints. Motivated by the recent discussions on algorithm biases as well as diversity and inclusion, we have examined the meaning of accessibility under the lens of inclusion and its role in enhancing CAPRIO's development. In this vision paper we discuss how a system like CAPRIO can become fully inclusive that it benefits users from all backgrounds.

In this demo paper, we present the new module of our HealthDist system that performs contact tracing in a privacy-preserving manner and considers the COVID-19 exposure risk. This is achieved by answering a new spatio-temporal query, dubbed ST-Aggregate Join, which calculates the COVID-19 exposure risk of an individual on their devices. It utilizes a special-purpose access structure to record the trajectories of users on their devices and optimize the ST-Aggregate Join processing. We demonstrate interactively using a smartphone application how our system can provide effective contact tracing within a university campus. We also illustrate how our new module is working through an intuitive web interface that shows the exposure risk of a person by coloring the trajectory of the infected person and the person(s) in high risk in a preloaded real dataset.

CAPRIO is an indoor-outdoor pedestrian path rec-ommendation system that optimizes for shortest distance. Its path-finding algorithm, ASTRO, takes into account a set of user-provided congestion constraints and as such can recommend paths that can reduce the risk of COVID-19 exposure. In this paper, we extend ASTRO to consider the changes on congestion when providing path recommendations for overlapping requests. Our new algorithm, called ASTRO-K, can provide K alternative paths that satisfy the congestion constraints of all the path requests within a short time-window. Our experimental eval-uation is conducted using two real-world datasets and shows that ASTRO-K can reduce the total average congestion of the recommended paths up to 4.5X with the trade-off of up to 7% increased total path time.

The COVID-19 pandemic poses new challenges in providing safe pedestrian navigation information that helps to reduce the risk of severe illness due to the highly contagious nature of the virus. In this paper, we present an innovative system, dubbed HealthDist, which utilizes the context (e.g., weather conditions), location (e.g., crowded areas) and user's preferences to support safe mobility. It consists of four modules that allow efficient contact tracing, social distancing, and isolation. HealthDist's modular design reduces the time and resources needed to provide accurate localization for measuring density in common spaces and measuring potential infection exposure, and recommend outdoor and indoor paths satisfying the user's preferences. HealthDist's initial deployment within a university campus demonstrated its capability to provide real time navigation information that reduces the COVID-19 exposure risk while at the same time satisfying the constraints defined by the user.

In this demo paper, we feature HealthDist, an innovative system that is an additional asset in the fight against the COVID-19 pandemic. HealthDist utilizes context (e.g., weather conditions), location (e.g., crowded areas), and user preferences to provide safe pedestrian paths which decrease the exposure to the virus causing COVID-19. Its modular design, consisting of four components, reduces the time and resources needed to provide accurate localization and indoor-outdoor path recommendations that satisfy the user's preferences. We demonstrate interactively using smartphones how HealthDist can provide real time navigation information within a university campus and illustrate the reduction of the COVID-19 exposure risk while satisfying the constraints defined by the user.Video: http://bit.ly/3bMicbs

Effectively and accurately forecasting the congestion in indoor spaces has become particularly important during the pandemic in order to reduce the risk of exposure to airborne viruses. However, there is a lack of readily available indoor congestion data to train such models. Therefore, in this demo paper we propose EPICGen , an experimental platform for indoor congestion generation to support congestion forecasting in indoor spaces. EPICGen consists of two components: (i) Grid Overlayer , which models the floor plans of buildings; and (ii) Congestion Generator , a realistic indoor congestion generator. We demonstrate EPICGen through an intuitive map-based user interface that enables end-users to customize the parameters of the system and visualize generated datasets.

The CAPRIOv2.0 system is the evolution of CAPRIO, our context-aware path recommendation system that has as its primary objectives the minimum outdoor exposure and distance of the recommended path. CAPRIOv2.0 offers enhanced indoor context-awareness in terms of accessibility and congestion. In this demonstration, we exhibit CAPRIOv2.0 and present its novel graph representation that integrates accessibility, congestion, indoor, and outdoor information to discover paths satisfying accessibility, outdoor exposure, and distance constraints of an individual. We further present a new spatial model index, called SMI-tree, which enables CAPRIO v2.0 to quickly forecast the congestion in corridors and hallways. Individuals can interactively engage with the CAPRIOv2.0 GUI using any of their devices to appreciate how our proposed structures and algorithms can provide an alternative context-aware path by combining outdoor, indoor, congestion and accessibility information.Video https://db.cs.pitt.edu/caprio/v2.

The Internet of Things (IoT) revolution has massively introduced sensor-rich tracking devices to an ever growing landscape of smart spaces (e.g., factories, hospitals, and ships). One problem that remains unsolved over the years is the localization problem for IoT, given that Satellite-based solutions are inaccurate in indoor spaces where human activity takes place 80-90% of the time. In this paper, we introduce a novel opensource architecture for IoT localization, coined Anyplace 4.0 IoT (A4IoT), which exploits signal fingerprinting to organize under the same roof a wide range of different localization technologies (e.g., Wi-Fi, BLE, Cellular, UWB, Computer Vision). We present the technical requirements of A4IoT inspired by the Alstom SA smart factory, operating worldwide in rail transport markets. A4IoT comprises a crowdsourcing architecture where deployers can collect and organize fingerprint signals inside smart spaces in a designated localization service running on the Edge (from Raspberry to Datacenter). The service incorporates timeseries databases for tracking targets and deployers can provide accurate room-level localization accuracy (≈ 2 m) on a variety of platforms (e.g., Android, Linux, Mac, Windows, Robot OS) but also integrate A4IoT through Web 2.0 endpoints to their software ecosystems.

A telecommunication company (telco) is traditionally only perceived as the entity that provides telecommunication services, such as telephony and data communication access to users. However, the radio and backbone infrastructure of such entities spanning densely most urban spaces and widely most rural areas, provides nowadays a unique opportunity to collect immense amounts of data that capture a variety of natural phenomena on an ongoing basis, e.g., traffic, commerce, mobility patterns and user service experience. The ability to perform analytics on the generated big data within tolerable elapsed time and share it with key smart city enablers (e.g., municipalities, public services, startups, authorities, and companies), elevates the role of telcos in the realm of future smart cities from pure network access providers to information providers. In this tutorial, we overview the state-of-the-art in telco big data analytics by focusing on a set of basic principles, namely: (i) real-time analytics and detection; (ii) experience, behavior and retention analytics; (iii) privacy; and (iv) storage. We also present experiences from developing an innovative such architecture and conclude with open problems and future directions.

During extreme weather conditions and natural disasters caused by meteorological phenomena, it is imperative to enable navigation that minimizes the outdoor section of recommended paths. Existing indoor-outdoor navigation and localization systems have evolved to support queries like the shortest distance, either outdoor or indoor, with additional constraints. However, most of them work in isolation and do not take into consideration the external natural conditions, like the weather, that an individual may experience walking outside during a polar vortex or heatwave. In this paper, we present CAPRIO, a context-aware path recommendation system whose objectives are two-fold: (i) minimizing outdoor exposure; and (ii) minimizing the distance of the recommended path. We propose a novel graph representation that integrates indoor and outdoor information to discover paths that satisfy outdoor exposure and distance constraints. We measure the efficiency of the proposed solution using two real datasets collected from the University of Pittsburgh and University of Cyprus campuses. We show that we can achieve comparable distance to the state-of-the-art in minimizing outdoor exposure.

Recently, navigation and localization systems have emerged to support queries like the shortest distance in either indoor or outdoor with additional constraints. These systems, however, neither combine the indoor and outdoor information nor consider the external natural conditions like the weather that one may face across an outdoor path. In this demonstration paper we present CAPRIO , which proposes and implements a novel graph representation that integrates indoor and outdoor information to discover paths that personalize outdoor exposure while minimizes the overall path length. We also demonstrate how unifying the graph algorithms for indoor and outdoor navigation enables significant optimizations that would not be possible otherwise.

In this demonstration paper, we present an integrated indoor signal management studio, coined Fingerprint Management Studio (FMS), which provides a spatio-temporal platform to: (i) manage the collection of location-dependent sensor readings (i.e., fingerprints) in indoor environments; (ii) estimate the localization accuracy based on the collected fingerprints; and (iii) assess Wi-Fi coverage and data rates. The demonstration will present the components comprising FMS, namely CSM (Crowd Signal Map), ACCES (Accuracy Estimation) and WS (Wi-Fi Surveying), through a compelling map-based visual analytic interface implemented on top of our open-source indoor navigation service, coined Anyplace. We will present FMS in two modes: (i) Online Mode, where attendees will be able to collect and analyze real fingerprints at the conference venue; and (ii) Offline Mode, where attendees will be able to interact with measurements of University campus in Cyprus, a Hotel in the US and an Expo in S. Korea.

In this paper, we present a novel decaying operator for Telco Big Data (TBD), coined TBD-DP (Data Postdiction). Unlike data prediction, which aims to make a statement about the future value of some tuple, our formulated data postdiction term, aims to make a statement about the past value of some tuple, which does not exist anymore as it had to be deleted to free up disk space. TBD-DP relies on existing Machine Learning (ML) algorithms to abstract TBD into compact models that can be stored and queried when necessary. Our proposed TBD-DP operator has the following two conceptual phases: (i) in an offline phase, it utilizes a LSTM-based hierarchical ML algorithm to learn a tree of models (coined TBD-DP tree) over time and space; (ii) in an online phase, it uses the TBD-DP tree to recover data within a certain accuracy. In our experimental setup, we measure the efficiency of the proposed operator using a ~10GB anonymized real telco network trace and our experimental results in Tensorflow over HDFS are extremely encouraging as they show that TBD-DP saves an order of magnitude storage space while maintaining a high accuracy on the recovered data.

In this demonstration paper, we present the TBD-DP operator, which relies on existing Machine Learning (ML) algorithms to abstract Telco Big Data (TBD) into compact models that can be stored and queried when necessary. Our proposed TBD-DP operator has the following two conceptual phases: (i) in an offline phase, it utilizes a LSTM-based hierarchical ML algorithm to learn a tree of models (coined TBD-DP tree) over time and space; (ii) in an online phase, it uses the TBD-DP tree to recover data within a certain accuracy. Our framework also includes visual and declarative interfaces for a variety of telco-specific data exploration tasks. We demonstrate the efficiency of the proposed operator using SPATE, which is a novel TBD visual analytic architecture we have developed. Our demo will enable attendees to interactively explore synthetic antenna signal traces, we will provide, in both visual and SQL mode. In both cases, the performance of the propositions will be quantitatively conveyed to the attendees through dedicated dashboards.

A Telecommunication company (Telco) is traditionally only perceived as the entity that provides telecommunication services, such as telephony and data communication access to users. However, the radio and backbone infrastructure of such entities spanning densely most urban spaces and widely most rural areas, provides nowadays a unique opportunity to collect immense amounts of data that capture a variety of natural phenomena on an ongoing basis, e.g., traffic, commerce and mobility patterns and user service experience. The ability to perform analytics on the generated big data within tolerable elapsed time and share it with key smart city enablers (e.g., municipalities, public services, startups, authorities, and companies), elevates the role of Telcos in the realm of future smart cities from pure network access providers to information providers. In this talk, we overview the state-of-the-art in Telco big data analytics by focusing on a set of basic principles, namely: (i) real-time analytics and detection; (ii) experience, behavior and retention analytics; (iii) privacy; and (iv) storage. We also present experiences from developing an innovative such architecture and conclude with open problems and future directions.

In the realm of smart cities, telecommunication companies (telcos) are expected to play a protagonistic role as these can capture a variety of natural phenomena on an ongoing basis, e.g., traffic in a city, mobility patterns for emergency response or city planning. The key challenges for telcos in this era is to ingest in the most compact manner huge amounts of network logs, perform big data exploration and analytics on the generated data within a tolerable elapsed time. This paper introduces SPATE, an innovative telco big data exploration framework whose objectives are two-fold: (i) minimizing the storage space needed to incrementally retain data over time, and (ii) minimizing the response time for spatiotemporal data exploration queries over recent data. The storage layer of our framework uses lossless data compression to ingest recent streams of telco big data in the most compact manner retaining full resolution for data exploration tasks. The indexing layer of our system then takes care of the progressive loss of detail in information, coined decaying, as data ages with time. The exploration layer provides visual means to explore the generated spatio-temporal information space. We measure the efficiency of the proposed framework using a 5GB anonymized real telco network trace and a variety of telco-specific tasks, such as OLAP and OLTP querying, privacy-aware data sharing, multivariate statistics, clustering and regression. We show that out framework can achieve comparable response times to the state-of-the-art using an order of magnitude less storage space.

In this demonstration paper, we present SPATE, an innovative telco big data exploration framework whose objectives are two-fold: (i) minimizing the storage space needed to incrementally retain data over time, and (ii) minimizing the response time for spatiotemporal data exploration queries over stored data. Our framework deploys lossless data compression to ingest streams of telco big data in the most compact manner retaining full resolution for data exploration tasks. We augment our storage structures with decaying principles that lead to the progressive loss of detail as information gets older. Our framework also includes visual and declarative interfaces for a variety of telco-specific data exploration tasks. We demonstrate SPATE in two modes: (i) Visual Mode, where attendees will be able to interactively explore synthetic telco traces we will provide, and (ii) SQL Mode, where attendees can submit custom SQL queries based on a provided schema.

A wide spectrum of Internet-scale mobile applications, ranging from social networking, gaming and entertainment to emergency response and crisis management, all require efficient and scalable All k Nearest Neighbor (AkNN) computations over millions of moving objects every few seconds to be operational. In this paper we present Spitfire, a distributed algorithm that provides a scalable and high-performance AkNN processing framework to our award-winning geo-social network named Rayzit. The proposed algorithm deploys a fast load-balanced partitioning along with an efficient replication-set selection, to provide fast main-memory computations of the exact AkNN results in a batch-oriented manner. We evaluate, both analytically and experimentally, how the pruning efficiency of the Spitfire algorithm plays a pivotal role in reducing communication and response time up to an order of magnitude, compared to three state-of-the-art distributed AkNN algorithms executed in distributed main-memory.

A wide spectrum of Internet-scale mobile applications, ranging from social networking, gaming and entertainment to emergency response and crisis management, all require efficient and scalable All k Nearest Neighbor (AkNN) computations over millions of moving objects every few seconds to be operational. Most traditional techniques for computing AkNN queries are centralized, lacking both scalability and efficiency. Only recently, distributed techniques for shared-nothing cloud infrastructures have been proposed to achieve scalability for large datasets. These batch-oriented algorithms are sub-optimal due to inefficient data space partitioning and data replication among processing units. In this paper, we present Spitfire, a distributed algorithm that provides a scalable and high-performance AkNN processing framework. Our proposed algorithm deploys a fast load-balanced partitioning scheme along with an efficient replication-set selection algorithm, to provide fast main-memory computations of the exact AkNN results in a batch-oriented manner. We evaluate, both analytically and experimentally, how the pruning efficiency of the Spitfire algorithm plays a pivotal role in reducing communication and response time up to an order of magnitude, compared to three other state-of-the-art distributed AkNN algorithms executed in distributed main-memory.

Abstract—The smartphone revolution has introduced a new era of social networks where users communicate over anonymous messaging platforms to exchange opinions, ideas and even carry out commerce. These platforms enable individuals to establish social interactions between strangers based on a common interest or attribute. In this paper we present Rayzit1, a novel anonymous crowd messaging architecture, which utilizes the location of each user to connect them instantly to their k Nearest Neighbors (kNN) as they move in space. Contrary to the very large body of location-based social networks that suffer from bootstrapping issues, our architecture enables a user to always interact with the geographically closest possible users around. We establish this communication using a fast computation of an All kNN query that generates a dynamic global social graph every few seconds. We present motivating application scenarios and the detailed back-end architecture that allows Rayzit to scale. We have collected and analyzed data from the interactions of thousands of active users and confirm our claims. Keywords—Crowd, Social, Mobile, Microblogging I.

Smartphones are nowadays equipped with a number of sensors, such as WiFi, GPS, accelerometers, etc. This capability allows smartphone users to easily engage in crowdsourced computing services, which contribute to the solution of complex problems in a distributed manner. In this work, we leverage such a computing paradigm to solve efficiently the following problem: comparing a query trace Q against a crowd of traces generated and stored on distributed smartphones. Our proposed framework, coined SmartTrace+, provides an effective solution without disclosing any part of the crowd traces to the query processor. SmartTrace+, relies on an in-situ data storage model and intelligent top-K query processing algorithms that exploit distributed trajectory similarity measures, resilient to spatial and temporal noise, in order to derive the most relevant answers to Q. We evaluate our algorithms on both synthetic and real workloads. We describe our prototype system developed on the Android OS. The solution is deployed over our own SmartLab testbed of 25 smartphones. Our study reveals that computations over SmartTrace+result in substantial energy conservation; in addition, results can be computed faster than competitive approaches.

In this demonstration paper, we present a powerful distributed framework for finding similar trajectories in a smartphone network, without disclosing the traces of participating users. Our framework, exploits opportunistic and participatory sensing in order to quickly answer queries of the form: “Report objects (i.e., trajectories) that follow a similar spatio-temporal motion to Q, where Q is some query trajectory.” SmartTrace, relies on an in-situ data storage model, where geo-location data is recorded locally on smartphones for both performance and privacy reasons. SmartTrace then deploys an efficient top-K query processing algorithm that exploits distributed trajectory similarity measures, resilient to spatial and temporal noise, in order to derive the most relevant answers to Q quickly and efficiently. Our demonstration shows how the SmartTrace algorithmics are ported on a network of Android-based smartphone devices with impressive query response times. To demonstrate the capabilities of SmartTrace during the conference, we will allow the attendees to query local smartphone networks in the following two modes: (i) Interactive Mode, where devices will be handed out to participants aiming to identify who is moving similar to the querying node; and (ii) Trace-driven Mode, where a large-scale deployment can be launched in order to show how the K most similar trajectories can be identified quickly and efficiently. The conference attendees will be able to appreciate how interesting spatio-temporal search applications can be implemented efficiently (for performance reasons) and without disclosing the complete user traces to the query processor (for privacy reasons)1. For instance, an attendee might be able to determine other attendees that have participated in common sessions, in order to initiate new discussions and collaborations, without knowing their trajectory or revealing his/her own trajectory either.