Location-based Services System Research Articles

User-Defined Privacy Grid System for Continuous Location-Based Services

Location-based services (LBS) require users to continuously report their location to a potentially untrusted server to obtain services based on their location, which can expose them to privacy risks. Unfortunately, existing privacy-preserving techniques for LBS have several limitations, such as requiring a fully-trusted third party, offering limited privacy guarantees and incurring high communication overhead. In this paper, we propose a user-defined privacy grid system called dynamic grid system (DGS); the first holistic system that fulfills four essential requirements for privacy-preserving snapshot and continuous LBS. (1) The system only requires a semi-trusted third party, responsible for carrying out simple matching operations correctly. This semi-trusted third party does not have any information about a user’s location. (2) Secure snapshot and continuous location privacy is guaranteed under our defined adversary models. (3) The communication cost for the user does not depend on the user’s desired privacy level, it only depends on the number of relevant points of interest in the vicinity of the user. (4) Although we only focus on range and $k$ -nearest-neighbor queries in this work, our system can be easily extended to support other spatial queries without changing the algorithms run by the semi-trusted third party and the database server, provided the required search area of a spatial query can be abstracted into spatial regions. Experimental results show that our DGS is more efficient than the state-of-the-art privacy-preserving technique for continuous LBS.

A Privacy-Preserving Continuous Location Monitoring System for Location-Based Services

To protect users’ private locations in location-based services, various location anonymization techniques have been proposed. The most commonly used technique is spatial cloaking, which organizes users’ exact locations into cloaked regions (CRs). This satisfies the K-anonymity requirement; that is, the querier is not distinguishable among K users within the CR. However, the practicality of cloaking techniques is limited due to the lack of privacy-preserving query processing capacity, for example, providing answers to the user's spatial queries based on knowledge of the user's cloaked location rather than the exact location. This paper proposes a cloaking system model called anonymity of motion vectors (AMV) that provides anonymity for spatial queries. The proposed AMV minimizes the CR of a mobile user using motion vectors. In addition, the AMV creates a ranged search area that includes the nearest neighbor (NN) objects to the querier who issued a CR-based query. The effectiveness of the proposed AMV is demonstrated in simulated experiments.

Development of location-based services for recommending departure stations to park and ride users: a note

In a recent study (Chen et al., 2014), a location-based service (LAS) system was designed for guiding park-and-ride users. However, in this service system, the formulae developed for evaluating utilities have some discrepancies, which motivated us to discuss the problems associated with weighted average and ordered-weighted average applications in the fields of LASs and ambient intelligence. This technical note reviews these discrepancies and provides corrections for overcoming them.

A New Distributed User-Demand-Driven Location Privacy Protection Scheme for Mobile Communication Network

With the development of mobile communication networks and intelligent terminals, recent years have witnessed a rapid popularization of location-based service (LBS). While obtaining convenient services, the exploitation of mass location data is inevitably leading to a serious concern about location privacy security. Obviously, high quality of service (QoS) will result in poor location privacy protection, so that a trade-off is needed to fulfill users’ individual demands for both sides. Although existing methods perform well in certain scenarios, few have considered the abovementioned balance problem. Therefore, by combiningk-anonymity-based cloaking technique and obfuscation method, a new distributed user-demand-driven (DUDD) location privacy protection scheme is put forward in this paper. The basic idea is still to select a subcloaking area within the cloaking area generated by Location Anonymization Server. Moreover, by using the improved LBS system model, this paper constructs a distributed framework, in which location privacy protection is wholly occupied in server side and LBS provider is only dedicated to QoS-guarantee. In addition, normalized privacy demand and QoS metrics are given and a user-defined weight parameter is introduced to ensure location privacy security without decreasing QoS. The feasibility of the proposed method is proved through simulation.

Short-term Prediction Method of Resources Occupancy for LBS Guidance System

Guidance system can improve the resources utilization of LBS (Location Based Service) system effectively, and the validity of guidance system depends on accurate predicting of the near-future system resources occupancy and its trend. Considering the strong randomicity of short-term characteristic of the trend, a multi-model fusion method integrating adaptive filter and ARMA (Auto Regressive Moving Average) model is proposed to predict the resources occupancy and trend accurately. With the method, observation series of recent resources occupancy is decomposed to different scales and reconstructed by wavelet transform firstly. According to the different features of series at different scale, for approximate signal, the adaptive filter algorithm is used to predict the trend of resources occupancy at coarse scale, and for detail signals in multiple fine scales, ARMA algorithms are adopted. Finally, integrating the prediction results of multi-model from different scales, the resources occupancy and trend with high prediction accuracy can be obtained. Experiment results show that the resources occupancy prediction accuracy of proposed method is higher than that of typical algorithms such as exponential smoothing and weighted Markov algorithms.

A Real-Time Location-Based Services System Using WiFi Fingerprinting Algorithm for Safety Risk Assessment of Workers in Tunnels

This paper investigates the feasibility of a real-time tunnel location-based services (LBS) system to provide workers’ safety protection and various services in concrete dam site. In this study, received signal strength- (RSS-) based location using fingerprinting algorithm and artificial neural network (ANN) risk assessment is employed for position analysis. This tunnel LBS system achieves an online, real-time, intelligent tracking identification feature, and the on-site running system has many functions such as worker emergency call, track history, and location query. Based on ANN with a strong nonlinear mapping, and large-scale parallel processing capabilities, proposed LBS system is effective to evaluate the risk management on worker safety. The field implementation shows that the proposed location algorithm is reliable and accurate (3 to 5 meters) enough for providing real-time positioning service. The proposed LBS system is demonstrated and firstly applied to the second largest hydropower project in the world, to track workers on tunnel site and assure their safety. The results show that the system is simple and easily deployed.

WiLoVe: A WiFi-coverage based Location Verification System in LBS

With the proliferation of mobile devices, location-based services (LBS) have penetrated into our daily life in recent years. In an LBS system, the users check in at different venues to acquire rewards such as virtual points or real-world coupons/discounts, and easily share with their friends the recent activities. While these rewards benefit benign users a lot, they are incentives for malicious users to cheat on their locations. Recent researches have revealed that location cheating can be launched automatically on a large scale at ease. In current practice, the defense against location cheating relies on the server side solution, which has been proven to be insufficient. In this paper, we propose a novel verification system named WiLoVe. It maps the physical area of a venue to the local WiFi coverage and involves the venue owner as the verifier, hence utilizes the user's capability of one-hop communication with the verifier to verify the user's presence at the venue. In this work, we implement the verifier as an independent application, which can easily be installed on the venue owner's existing devices (laptops, cellphones, etc.). Hence, no additional hardware is needed. An adaptive algorithm is designed to defend against proxy attacks based on the check-in delay. Extensive experiments show that WiLoVe achieves low false rate, as well as consistent user experience, acceptable power consumption, and good applicability to different WiFi environments.

Building-linked Location-based Instantaneous Services System

For services which are meant to be used mainly inside buildings, a distribution using global app stores is inappropriate. Instead this work presents a provisioning system (BLISS) for building-linked location-based services. The multi-purpose application MultiApp implements the client-side of the BLISS specification. When a user enters a building, MultiApp instantaneously detects available services and allows to install and execute them. The client part of services is executed within the MultiApp environment and can provide functionalities similar to those offered by native applications. BLISS facilitates developing indoor location-based services by providing bi-directional communication between service providers and clients.

Research on Customized Indoor Route Recommendation

Research in this paper focuses on route recommendation for customers in shopping malls for a LBS(Location-based service ) system. Besides the shopping places selected by a customer, this system can recommend shopping places according to customers history record and similar customers history record analysis. In addition, the length of all routes between two walking destinations, and the traffic density on the routes are two primary factors when route optimization is done in the system. The algorithm referred above have been implemented. A large number of testing showed that the algorithm was efficient to meet the actual need. !

Proximity-Based Security Techniques for Mobile Users in Wireless Networks

In this paper, we propose a privacy-preserving proximity-based security system for location-based services in wireless networks, without requiring any pre-shared secret, trusted authority, or public key infrastructure. In this system, the proximity-based authentication and session key establishment are implemented based on spatial temporal location tags. Incorporating the unique physical features of the signals sent from multiple ambient radio sources, the location tags cannot be easily forged by attackers. More specifically, each radio client builds a public location tag according to the received signal strength indicators, sequence numbers, and media access control (MAC) addresses of the ambient packets. Each client also keeps a secret location tag that consists of the packet arrival time information to generate the session keys. As clients never disclose their secret location tags, this system is robust against eavesdroppers and spoofers outside the proximity range. The system improves the authentication accuracy by introducing a nonparametric Bayesian method called infinite Gaussian mixture model in the proximity test and provides flexible proximity range control by taking into account multiple physical-layer features of various ambient radio sources. Moreover, the session key establishment strategy significantly increases the key generation rate by exploiting the packet arrival time of the ambient signals. The authentication accuracy and key generation rate are evaluated via experiments using laptops in typical indoor environments.

A Smartphone Indoor Positioning Method

Location based services are very useful to human beings. The vehicle navigation service that is used by almost all drivers in the world is an example location based service. As the man made constructions are getting bigger and bigger, indoor location based services are demanded. Matter of fact, researches for indoor location based service started in the early 1990s and developing techniques with which universally available efficient indoor location based service systems can be built is one of the hottest current research issues. Considering the features of smart phones, its computing power and the sensor devices equipped on it, moreover it is one of the most popular personal belongings, we conclude that a smart phone is the most ideal device on which indoor location based service systems should be executed. Therefore, we propose a method of indoor positioning that determines the user's current position with the smart phone's sensor values. Referring to the accelerometer values, our method counts steps. With the orientation values, our method estimates the direction. With the step count and the direction, our method determines the current location of the user. Referring to the floor map, our method adjusts the user's current location from time to time. We have implemented the proposed method on Android smart phones and our test results are discussed in this paper.

Pseudo-Location Updating System for privacy-preserving location-based services

With the rapid development of location-aware devices such as smart phones, Location-Based Services (LBSs) are becoming increasingly popular. Users can enjoy convenience by sending queries to LBS servers and obtaining service information that is nearby. However, these queries may leak the users' locations and interests to the un-trusted LBS servers, leading to serious privacy concerns. In this paper, we propose a Privacy-Preserving Pseudo-Location Updating System (3PLUS) to achieve k-anonymity for mobile users using LBSs. In 3PLUS, without relying on a third party, each user keeps pseudo-locations obtained from both the history locations and the encountered users, and randomly exchanges one of them with others when encounters occur. As a result, each user's buffer is disordered. A user can obtain any k locations from the buffer to achieve k-anonymity locally. The security analysis shows the security properties and our evaluation results indicate that the user's privacy is significantly improved.

Analysis for Changes of Mode Choice Behavior from Providing Real-time Schedule for Public Transportation by Smartphone Application

Public Transport Information Service which use smartphone Apps has received attention as the way of solution that reduced transport problem. Smartphone can offer real-time information because of a LBS(Location Based Service) system. This study try to find out which factor affect mode choice ratio of public transport, especially smartphone Apps. The result shows that rising oil price, traffic congestion, public information service with smartphone apps, BIS(Bus Information System) factors get 0.39, 0.27, 0.18, 0.16 scores with paired comparison. Younger and student respondents prefer smart phone public information service. Decision Tree shows that the most important decision factor is smartphone information service factor.

Seal

Location-based services (LBS) have become more and more ubiquitous recently. Existing methods focus on finding relevant points-of-interest (POIs) based on users' locations and query keywords. Nowadays, modern LBS applications generate a new kind of spatio-textual data, regions-of-interest (ROIs), containing region-based spatial information and textual description, e.g., mobile user profiles with active regions and interest tags. To satisfy search requirements on ROIs, we study a new research problem, called spatio-textual similarity search: Given a set of ROIs and a query ROI, we find the similar ROIs by considering spatial overlap and textual similarity. Spatio-textual similarity search has many important applications, e.g., social marketing in location-aware social networks. It calls for an efficient search method to support large scales of spatio-textual data in LBS systems. To this end, we introduce a filter-and-verification framework to compute the answers. In the filter step, we generate signatures for the ROIs and the query, and utilize the signatures to generate candidates whose signatures are similar to that of the query. In the verification step, we verify the candidates and identify the final answers. To achieve high performance, we generate effective high-quality signatures, and devise efficient filtering algorithms as well as pruning techniques. Experimental results on real and synthetic datasets show that our method achieves high performance.

A context-aware scheme for privacy-preserving location-based services

We address issues related to privacy protection in location-based services (LBSs). Most existing privacy-preserving LBS techniques either require a trusted third-party (anonymizer) or use cryptographic protocols that are computationally and communicationally expensive. Our design of privacy-preserving techniques is principled on not requiring a trusted third-party while being highly efficient in terms of time and space complexities. The problem has two interesting and challenging characteristics: First, the degree of privacy protection and LBS accuracy depends on the context, such as population and road density, around a user’s location. Second, an adversary may violate a user’s location privacy in two ways: (i) based on the user’s location information contained in the LBS query payload and (ii) by inferring a user’s geographical location based on the device’s IP address. To address these challenges, we introduce CAP, a context-aware privacy-preserving LBS system with integrated protection for both data privacy and communication anonymity. We have implemented CAP and integrated it with Google Maps, a popular LBS system. Theoretical analysis and experimental results validate CAP’s effectiveness on privacy protection, LBS accuracy, and communication QoS (Quality-of-Service).

Building a targeted mobile advertising system for location-based services

Over the years, mobile advertising has grown to become a technology that allows an advertiser to promote products or services to targeted users efficiently and effectively. This is because the ubiquitous nature of mobile devices can provide contextual information and allow users to demonstrate preferences. This study proposes a targeted mobile advertising system (TMAS) that works as a platform to provide both merchants and consumers with context-aware advertisements. The approach integrates the advantages of both mobile and targeted advertising to allow merchants to disseminate location-based targeted advertisements while providing pull-type and personalized advertisements for consumers. To demonstrate the TMAS, we build a platform to provide highly relevant advertising to consumers and to guarantee that advertisements have an equal opportunity of being presented to consumers.

위성 DMB 시스템을 이용한 위치 기반 서비스 구현

본 논문에서는 위성 DMB (satellite-digital multimedia broadcasting, S-DMB) 송수신 시스템을 이용한 위치 기반 서비스 (location based services, LBS) 구현 방법에 대하여 제안한다. S-DMB 송출 신호는 2 GHz 대역의 주파수를 사용하므로 직진성은 강하지만 회절성이 약한 특징을 갖고 있다. 따라서 S-DMB 시스템에서는 실내 및 지하 공간 등의 음영 지역이 다수 존재하게 되는데, 이러한 음영지역에서는 갭필러 (gap filler)라는 음영지역 중계기를 통해서 S-DMB 신호를 수신하게 된다. 이러한 갭필러의 식별정보 (gap filler ID)를 확인하면 갭필러가 설치된 지역을 알 수 있다. 따라서 본 논문에서는 S-DMB 신호를 수신할 수 있는 단말기에서 S-DMB 파일럿 신호 중 갭필러 식별정보를 이용하여, 관심 위치 정보 등록, 목적지 도착 알림, 및 지역 정보 알림 기능 등의 LBS를 구현하는 방법을 제안한다. 제안한 LBS 구현 방법의 성능을 검증하기 위한 실험에서는 S-DMB 수신칩이 갭필러 식별정보를 애플리케이션 프로세서 (application processor, AP)로 전달하도록 단말기의 펌웨어 (firmware)를 수정하여 LBS 구현 테스트를 진행하였다. In this paper, the implementation of location based services (LBS) using S-DMB (satellite-digital multimedia broadcasting) system was proposed. In S-DMB System, the frequency of transmitted signal is about 2 GHz which has a characteristics of strong straightness but weak diffraction so that there are many shade areas such as indoors and underground spaces. Therefore the signal transmitted from the satellite should be retransmitted by the earth repeaters called as gap filler. Because each gap filler has its own identification value, the gap filler ID introduces the area in which the gap filler was installed. Generally, the 51st data symbols of S-DMB pilot signal transmitted from the satellite are padded by dummy value and gap filler ID is embedded in this pilot symbol by the gap filler when S-DMB signals are retransmitted by gap fillers. So using gap filler ID of S-DMB system, LBS such as region registration, distance and time to destination, alarm of local area information could be implemented. In the experiment to prove the performance of the proposed LBS system using the gap filler ID of the S-DMB system, the firmware of S-DMB chip composing of RF and baseband parts was lightly modified so that application processor was able to manipulate the gap filler ID and the its related regional information.

웹 서비스 이용 옥내위치기반 콘텐츠 디스플레이 시스템 구현

Map rendering, positioning, database managements are key elements of location based services. Google map and GPS (Global Positioning System) have become a very popular solution for map rendering and positioning, respectively. They are very effective and yet free of charge. However, they cannot be used for an indoor location based service system. We cannot render a building drawing with Google map, we cannot determine a moving object`s position when it is indoor. This paper introduces our web services of rendering drawings, indoor positioning, and multimedia contents up-loading and playing so that any programmers can use them in developing indoor location based service systems. In order to experimentally show the efficiency of our web services, we have built a location based contents displaying system for museum visitors with them.

End-User Attitudes towards Location-Based Services and Future Mobile Wireless Devices: The Students’ Perspective

Nowadays, location-enabled mobile phones are becoming more and more widespread. Various players in the mobile business forecast that, in the future, a significant part of total wireless revenue will come from Location-Based Services (LBS). An LBS system extracts information about the user’s geographical location and provides services based on the positioning information. A successful LBS service should create value for the end-user, by satisfying some of the users’ needs or wants, and at the same time preserving the key factors of the mobile wireless device, such as low costs, low battery consumption, and small size. From many users’ perspectives, location services and mobile location capabilities are still rather poorly known and poorly understood. The aim of this research is to investigate users’ views on the LBS, their requirements in terms of mobile device characteristics, their concerns in terms of privacy and usability, and their opinion on LBS applications that might increase the social wellbeing in the future wireless world. Our research is based on two surveys performed among 105 students (average student age: 24 years) from two European technical universities. The survey questions were intended to solicit the youngsters’ views on present and future technological trends and on their perceived needs and wishes regarding Location-Based Services, with the aim of obtaining a better understanding of designer constraints when building a location receiver and generating new ideas related to potential future killer LBS applications.

An implementation of location-based service system with cell identifier for detecting lost mobile

Abstract This paper presents a software development on Android Platform which applies cell identifier method for improving the accuracy of indoor localization. The objective of this research is to provide a detectable system, “Mobile Detective”, for tracking and finding clues of lost mobiles. In general, the location-based service, a software application which retrieves information about where a mobile device is located, uses GPS (Global Positioning System) to indicate the geographical position of the mobile device. Though GPS provides efficient outdoor localization, it does not work well indoor and not all mobile devices have built-in GPS receiver. Therefore, GPS may not be suitable for tracking lost mobiles. In order to solve this problem, cell identifier which indicates mobile device position by using station base information is introduced in this research. The location tracking process is run as background process by using Android service and it automatically repeats sending this information in an interval of time. The results from this process composed of position and mobileˆˆe2ˆˆ80ˆˆ99s particular information: SIM code and IMEI (International Mobile Equipment Identity), are sent from the lost mobile to the recipient. The results are displayed in two interface modes which are text message and GUI on Google map. User can use these clues to notify mobile provider and police in order to retrieve the lost mobile