Towards System Implementation and Data Analysis for Crowdsensing Based Outdoor RSS Maps

Inference latency prediction for CNNs on heterogeneous mobile devices and ML frameworks

This paper proposes a semantic image adaptation scheme for heterogeneous mobile display devices. This scheme aims to provide mobile users with the most desired image content by integrating the content semantic importance with user preferences under limited mobile display constraints. The main contributions of the proposed scheme are: 1) seamless integration of mobile user supplied query information with low level image features to identify semantically important image contents; 2) integration of semantic importance and user feedback to dynamically update mobile user preferences; and 3) perceptually optimized adaptation for image display on mobile devices. In order to bridge the semantic gap for adaptation, we design a Bayesian fusion approach to properly integrate low level features with high level semantics. To accommodate the variation of user preferences, the system involves mobile users in the adaptation process with only a few simple feedbacks so as to present to the users most interesting content on mobile devices. Eventually, perceptually optimized adaptation is performed to present the best image content for mobile users according to mobile display capacities. Extensive experiments have been carried out based on several common events defined in Kodak's consumer image database. These experiments show that by utilizing the proposed semantic adaptation scheme with integration of the semantics and mobile user preferences, perceptually relevant adaptation can be effectively carried out to tailor the image towards user intentions under the mobile environment constraints.

IPTV is considered a stepping stone into a ubiquitous area as the home networks' main business model. We propose the P2P chord service overlay network model to provide services and make sharing resources among mobile devices easy. The proposed SGN (Spot-based Group Network) uses hierarchical service delivery network architecture. It delivers services and resources among distributed mobile devices. We suggest three business models which are plausible ubiquitous service architectures.

The paper focuses on the performance analysis of the timing acquisition scheme based on received signal strength (RSS) measurements for ultra-wideband (UWB) communication systems. To our knowledge, few paper discusses the performance of the timing acquisition scheme based on RSS measurements for UWB in details. The timing acquisition scheme based on RSS measurements has many advantages, such as low cost, high speed and robustness. However, low transmission power limitation and complicated indoor multipath propagation environments make it difficult to measure accurate RSS at the receiver and affect the accuracy of the time delay offset estimation for the local template signals. In addition, the time variation of the indoor channel state can form a multiple-to-one mapping relation between the RSS measurements and the distance, which largely limits the method application. In the paper, we analyze the accuracy of time delay offset estimation for this method by deriving the Cramer-Rao lower bound (CRLB). The number results show that the accuracy of the timing acquisition method based on RSS measurements suffers from both the UWB signal transmission speed and the varying distance between the transmitter and receiver. It is noted that though the accuracy of the method can hardly fulfil the fine timing acquisition requirement for UWB systems, it will largely reduce the coarse timing acquisition time and improve the performance for UWB timing acquisition systems if combined with other timing acquisition ones

Mobile crowdsensing enables convenient sensory data collection from a large number of mobile devices and has found various applications. In the real practice, however, the sensory data collected from various mobile devices are usually unreliable. To extract truthful information from the unreliable sensory data in mobile crowdsensing, the topic of truth discovery has received wide attention recently, which essentially operates by estimating user reliability degrees and performing reliability-aware truthful aggregation. Despite the effectiveness, applying truth discovery in mobile crowdsensing faces several privacy and security challenges. First, the sensory data and reliability degrees of users may reveal privacy-sensitive information and, thus, demand strong protection. Second, the requester that initiates a crowdsensing application usually needs to have monetary investment, so the inferred truths can be the requester's proprietary information and should be protected as well. In this paper, we propose a new system architecture enabling encrypted truth discovery in mobile crowdsensing. We focus on general and realistic mobile crowdsensing scenarios with varying levels of user participation, and our security design is built on the confidence-aware truth discovery (CATD) approach for its state-of-the-art accuracy in such scenarios. In our system architecture, users send encrypted sensory data to the cloud, where CATD is then conducted in the encrypted domain. The final encrypted inferred truths are sent to the requester for decryption. Along the whole workflow, the sensory data and reliability degrees of users, as well as the inferred truths of the requester, are kept private. Extensive experiments over real-world mobile crowdsensing dataset show that our design achieves practical performance on mobile devices.

The smartphone and mobile devices are gradually becoming the most widely distributed sensor nodes. The nodes communicate with others to form the mobile ad hoc network, which provides network infrastructure for context-awareness and supports mobile crowd sensing (MCS). In our view, MCS can be considered as an emerging paradigm for internet of things. The remote server is a collection of service applications. With the support of mobile cloud computing (MCC) services, devices based on sensors constitute a people-centric ubiquitous MCS for convenient collection of context-aware information. In this paper, we implement the conceptual MCS architecture with the support of MCC and the remote server system architecture with context-awareness. Then we analyses the infrastructure and features of MCS for context-awareness. A paradigm regarding intelligent transportation system (ITS) with cloud-assisted MCS support has been proposed to integrate and share resources of ITS and social network in a large degree through MCC and cloud of cloud. The rest of the paper reviews the possible attacks, security issues and challenges.

Physical activity is closely related to one's health status. Especially the intensity of physical activity is more important than other features for health benefits, which can be computed by the number of steps. With the advent of mobile devices, pedometer system can be implemented on mobile devices with their built-in sensors. However, due to the variety of types of platforms and devices, it is hard to ensure the consistency of step counting. In this paper, we propose a robust pedometer system for healthcare services, which ensures the consistent results of step counting upon heterogeneous platforms and multiple mobile devices. Based on the proposed system, we present the actual implementation of pedometer applications for different platforms and devices. We examine our implementation to verify that it is useful in real life with respect to the accuracy of step counting and battery consumption.

Currently there is almost ubiquitous availability of wireless signaling for data communications within commercial building complexes resulting in receiver signal strength (RSS) observables that are typically sufficient for generating viable location estimates of mobile wireless devices. However, while RSS observables are generally plentiful, achieving an accurate estimation of location is difficult due to several factors affecting the electromagnetic coupling between the mobile antenna and the building access points that are not modeled and hence contribute to the overall estimation uncertainty. Such uncertainty is typically mitigated with a moderate redundancy of RSS sensor observations in combination with other constraints imposed on the mobile trajectory. In this paper, the Fisher Information (FI) of a set of RSS sensor observations in the context of variables related to the mobile location is developed. This provides a practical method of determining the potential location accuracy for the given set of wireless signals available. Furthermore, the information value of individual RSS measurements can be quantified and the RSS observables weighted accordingly in estimation combining algorithms. The practical utility of using FI in this context was demonstrated experimentally with an extensive set of RSS measurements recorded in an office complex. The resulting deviation of the mobile location estimation based on application of weighted likelihood processing to the experimental RSS data was shown to agree closely with the Cramer Rao bound determined from the FI analysis.

Received Signal Strength (RSS) localization is widely used due to its simplicity and availability in most mobile devices. The RSS channel model is defined by the propagation losses and the shadow fading. These parameters might vary over time because of changes in the environment. In this paper, the problem of tracking a mobile node by RSS measurements is addressed, while simultaneously estimating a two-slope RSS model. The methodology considers a Kalman filter with Interacting Multiple Model architecture, coupled to an on-line estimation of the observation's variance. The performance of the method is shown through numerical simulations in realistic scenarios.

With growing technology, Location Based Services (LBSs) are becoming a vital part of life. The rapid development of mobile internet has offered an opportunity for Wi-Fi indoor positioning to come under the spotlight due to its low cost. Here, indoor positioning is performed using Wi-Fi. The earlier solutions like GPS does not provide efficient positioning in indoor environment due to weak signal reception which makes Wi-Fi more reliable. However, nowadays the accuracy of the traditional indoor positioning algorithms like trilateration cannot meet the practical requirement. This paper proposes the performance analysis of indoor positioning algorithms using Wi-Fi technology based on Received Signal Strength (RSS) from the access points in the network. The positioning algorithms are based on location fingerprinting consisting of two stages: The offline database creation and the online positioning. The RSS values obtained by the mobile device at reference points are sent to the server where all the location fingerprints of all reference points are stored in a database. Coordinates of user position are calculated using positioning algorithms and the position is displayed in terms of 2Dcoordinates of the room and indoor map. Basic Fingerprint algorithm, RSS Fingerprint with minimum Euclidean Distance algorithm and RSS Fingerprint with Euclidean Distance and k-nearest neighbors' algorithm were implemented. Moreover comparison of their performance was carried out in terms of accuracy of position. From the result, it is found that an average accuracy of 0.4962 meters was achieved by RSS Fingerprint with minimum Euclidean distance algorithm.

With the proliferation of the Internet of Things (IoT), employing Received Signal Strength (RSS) as a metric to determine the location of a target (e.g., person or mobile device) is of great interest in terms of cost and ease of implementation. Indeed, RSS measurements can be easily obtained for most off-the-shelf devices, such as WiFi- or ZigBee compatible devices or sensors. This paper deals with the indoor localization problem in wireless sensor networks (WSNs) and proposes a new approach for radio signal propagation modelling and localization estimation, that accounts for the imperfection of RSS measurements and the reliability of RSS sources by using the Dempster-Shafer Theory (DST). In the signal propagation modelling, key information regarding the geometry of indoor environment that is divided into zones separated by walls (zoning), are considered. Based on the number of walls, the RSS irregularities are estimated using different distance intervals, which are weighted by a probability density determined experimentally. To estimate the location of a target node, the PCR6 rule is used to combine the belief masses of the positions obtained from the probability density. In order to evaluate the performance of the proposed approach, an experimental WSN has been deployed in a living apartment. The obtained results demonstrate that the proposed approach improves the localization accuracy compared to the case without zoning. Moreover, the obtained localization mean error proves the feasibility of a precise localization of humans in indoor environments in the case of Ambient Assisted Living and Social Robotics applications.

Grid computing using wireless networks is receiving increasing attention and is expected to become a critical part of future grid computing. However, the inherent challenges of mobile environments such as mobility management, disconnected operation, device heterogeneity, service discovery, and resource sharing are significant issues in mobile grid computing. To achieve the best performance in a mobile grid computing environment, the mobile devices with the lowest probability of mobility should be selected for use first. We therefore focus on the idle state of mobile devices and use IP-paging scheme to identify the idle mobile devices. For this, we propose a user-defined checkpoint technique for task migration, which is based on the information of when a mobile device will leave the network or stop due to low battery. Our checkpoint technique performs checkpoints by two conditions: when a mobile device leaves its current cell and when it turns off due to low battery capacity.KeywordsMobile GridIP-PagingTask MigrationCheckpoints

Mobile crowdsensing (MCS) counting on the mobility of massive workers helps the requestor accomplish various sensing tasks with more flexibility and lower cost. However, for the conventional MCS, the large consumption of communication resources for raw data transmission and high requirements on data storage and computing capability hinder potential requestors with limited resources from using MCS. To facilitate the widespread application of MCS, we propose a novel MCS learning framework leveraging on blockchain technology and the new concept of edge intelligence based on federated learning (FL), which involves four major entities, including requestors, blockchain, edge servers and mobile devices as workers. Even though there exist several studies on blockchain-based MCS and blockchain-based FL, they cannot solve the essential challenges of MCS with respect to accommodating resource-constrained requestors or deal with the privacy concerns brought by the involvement of requestors and workers in the learning process. To fill the gaps, four main procedures, i.e., task publication, data sensing and submission, learning to return final results, and payment settlement and allocation, are designed to address major challenges brought by both internal and external threats, such as malicious edge servers and dishonest requestors. Specifically, a mechanism design based data submission rule is proposed to guarantee the data privacy of mobile devices being truthfully preserved at edge servers; consortium blockchain based FL is elaborated to secure the distributed learning process; and a cooperation-enforcing control strategy is devised to elicit full payment from the requestor. Extensive simulations are carried out to evaluate the performance of our designed schemes.

Crowdsourcing has gained increasing interest during the last years as means for solving complex tasks with the help of a flexible group of contributors. The crowd can contribute with collecting data in the field, completing map information or votes for ideas or products. Even though the participation of large numbers of users with heterogeneous devices in crowdsourcing is a highly recurrent task, generic infrastructures for crowdsourcing can be hardly found. Especially the management of users, mobile devices and contributed data has to be repetitively implemented in new projects. To ease the development of crowdsourcing applications, in this paper we propose a generic platform for crowdsourcing supporting diverse crowdsourcing scenarios, the ability to handle large numbers of users and the involvement of heterogeneous mobile devices. The evaluation is based on scalability and performance experiments in order to demonstrate the feasibility of our approach.

Security and Energy-aware Collaborative Task Offloading in D2D communication