Virtual Location Research Articles

Computation-efficient virtual sensing approach with multichannel adjoint least mean square algorithm

Multichannel active noise control (ANC) systems are designed to create a large zone of quietness (ZoQ) around the error microphones, however, the placement of these microphones often presents challenges due to physical limitations. Virtual sensing technique that effectively suppresses the noise far from the physical error microphones is one of the most promising solutions. Nevertheless, the conventional multichannel virtual sensing ANC (MVANC) system based on the multichannel filtered reference least mean square (MCFxLMS) algorithm often suffers from high computational complexity. This paper proposes a feedforward MVANC system that incorporates the multichannel adjoint least mean square (MCALMS) algorithm to overcome these limitations effectively. Computational analysis demonstrates the improvement of computational efficiency and numerical simulations exhibit comparable noise reduction performance at virtual locations compared to the conventional MCFxLMS algorithm. Additionally, the effects of varied tuning noises on system performance are also investigated, providing insightful findings on optimizing MVANC systems.

Location Privacy Protection for the Internet of Things with Edge Computing Based on Clustering K-Anonymity.

With the development of the Internet of Things (IoT) and edge computing, more and more devices, such as sensor nodes and intelligent automated guided vehicles (AGVs), can serve as edge devices to provide Location-Based Services (LBS) through the IoT. As the number of applications increases, there is an abundance of sensitive information in the communication process, pushing the focus of privacy protection towards the communication process and edge devices. The challenge lies in the fact that most traditional location privacy protection algorithms are not suited for the IoT with edge computing, as they primarily focus on the security of remote servers. To enhance the capability of location privacy protection, this paper proposes a novel K-anonymity algorithm based on clustering. This novel algorithm incorporates a scheme that flexibly combines real and virtual locations based on the requirements of applications. Simulation results demonstrate that the proposed algorithm significantly improves location privacy protection for the IoT with edge computing. When compared to traditional K-anonymity algorithms, the proposed algorithm further enhances the security of location privacy by expanding the potential region in which the real node may be located, thereby limiting the effectiveness of "narrow-region" attacks.

VLR-BPP: An intelligent virtual location replacement based bilateral privacy-preserving architecture for edge cloud systems

Mobile Crowdsourcing (MCS) has emerged as a significant edge-cloud computing paradigm in which workers perceive data at the network edge and report it to cloud-based computing services for processing, enabling the construction of various applications. Consequently, it is imperative to achieve Bilateral Location Privacy-Preserving (BLPP) to protect the privacy of both Data Requester (DR) and workers, as disclosing location information entails many sensitive details that can result in losses for DR and workers alike. The Local Differential Privacy (LDP) approach is widely employed in Privacy-Preserving (PP) techniques due to its inherent advantages, wherein owners release data with added noise, allowing for proactive customization of privacy strength without relying on any third party. However, the current state of LDP methods presents a dilemma: when privacy protection is strong, introducing excessive location noise can lead to a decrease in the accuracy of task-worker matching, while a high rate of task-worker matching necessitates the compromise of privacy strength. In this paper, an intelligent Virtual Location Replacement based enhanced Bilateral Privacy-Preserving (VLR-BPP) architecture is proposed to improve privacy protection strength and matching accuracy in MCS simultaneously. Within the VLR-BPP architecture, a Bipartite-Graph-based Matrix Completion (BGMC) model is employed to establish the spatiotemporal correlations among data. Then, a Virtual Location Replacement (VLR) strategy is proposed to obfuscate the locations of tasks or workers to their highly correlated virtual location before publishing. Based on VLR, three preemptive location virtualization approaches are introduced: Only Task Location Virtual (OTLV), Only Workers Location Virtual (OWLV), and Both Task and Workers Location Virtual (BTWLV). For workers and DR, Randomized Response (RR) techniques and Random Matrix Multiplication Mechanism (RMM) are used to implement LDP independently. A greedy algorithm is adopted to recruit workers for tasks. In response to the data submitted by workers, BGMC imputation mechanism is utilized to enhance data quality. Finally, simulations based on real-world datasets demonstrate that the performance of our architecture surpasses existing state-of-the-art methods in privacy protection and data collection quality by 18.92∼38.17% and 15.49∼50.77%, respectively.

Creative arts and resilient communities

This editorial serves to outline key themes emerging through the articles presented in this volume. As we all navigate conflicts and challenges of various proportions, the question of resilience-building is of particular interest to socially engaged creative practitioners. Working in diverse geographical and virtual locations across the fields of theatre, textile craft, curatorial practices and cultural leadership, authors here explore these themes through their work with communities: art as a practice of cultural leadership points us towards social cohesion; engagement with art strengthens attachment to place uprooted by ecological disaster; imaginative and creative practices, whether material or performative, force us to consider marginalized forms of knowledge and expertise.

The Cybercrime Acts and the Electronic Transaction in International Law

Cyberthreats “Cybercrime” is a “criminal offence that may be committed on or through a computer system generally connected to a network”. As a result, it is a new type of crime and delinquency that varies from previous forms in that it takes place in a virtual location known as “cyberspace”. In recent years, the democratisation of computer access and the globalisation of networks have both played a role in the growth of cybercrime. In fact, not isolated and the institutions in several States are fully aware of the seriousness of this phenomenon, which goes beyond the borders of each State. If all members of Jordan’s criminal justice system are unaware of sophisticated computer and electronic device technologies, cybercrime will continue to rise. Despite technological developments and the information revolution, some states limits the subject of criminal protection to cash and fails to protect information funds against fraudulent acquisition.International law plays a significant role in combating cybercrime and establishing guidelines for cooperation among nations.

ZSCC suppression method for parallel three-level inverters based on model predictive control with virtual location vector

ZSCC suppression method for parallel three-level inverters based on model predictive control with virtual location vector

Come Look at This: Supporting Fluent Transitions between Tightly and Loosely Coupled Collaboration in Social Virtual Reality.

Collaborative work in social virtual reality often requires an interplay of loosely coupled collaboration from different virtual locations and tightly coupled face-to-face collaboration. Without appropriate system mediation, however, transitioning between these phases requires high navigation and coordination efforts. In this paper, we present an interaction system that allows collaborators in virtual reality to seamlessly switch between different collaboration models known from related work. To this end, we present collaborators with functionalities that let them work on individual sub-tasks in different virtual locations, consult each other using asymmetric interaction patterns while keeping their current location, and temporarily or permanently join each other for face-to-face interaction. We evaluated our methods in a user study with 32 participants working in teams of two. Our quantitative results indicate that delegating the target selection process for a long-distance teleport significantly improves placement accuracy and decreases task load within the team. Our qualitative user feedback shows that our system can be applied to support flexible collaboration. In addition, the proposed interaction sequence received positive evaluations from teams with varying VR experiences.

Between-Tactor Display Using Dynamic Tactile Stimuli for Directional Cueing in Vibrating Environments.

Torso-worn vibrotactile devices have been used in many studies on directional cueing and navigation in environments where visual feedback is limited. These devices aim to indicate directions with high resolution while using the smallest possible number of vibration motors (tactors). Resolution can be increased using between-tactor displays, but their performance in vibrating environments (e.g., a helicopter) are unknown. This study proposes a between-tactor display using dynamic stimuli and verifies its effectiveness when the user sits in a vibrating chair. We developed a waist belt device that displays 12 directions using 6 tactors. Static stimuli display virtual (between-tactor) locations by constantly vibrating two adjacent tactors equally, whereas dynamic stimuli move the virtual vibration position back and forth between tactors. We performed two studies in which participants felt tactile stimuli and used a joystick to move a cursor on a screen to a target in the perceived direction. Direction recognition accuracy and task completion time were measured under combined conditions of two belt orientations (tactor alignments), with and without chair vibration, and with and without audio white noise to mask tactor sound. In all conditions, dynamic stimuli increased recognition accuracy while maintaining task completion time compared to static stimuli.

Test-Retest Reliability of Virtual Acoustic Space Identification Test in School-Going Children.

The virtual acoustic space identification (VASI) test was designed to assess spatial-hearing acuity by simulating sound location perception in a closed field (under headphones). The utility of this tool in children can be asserted only if the test results are consistent across measurement sessions, which is evaluated in this study using test-retest reliability assessments. The VASI test assessed the spatial abilities of 40 typically developing school-aged children aged 7-13 years (M age = 10.47 ± 1.83 years, 22 boys, 18 girls). The test consisted of eight virtual location percepts (with 45° separation) produced under headphones (Sennheiser HD 569). Each spatial percept was presented randomly 7 times at 65 dB SPL. Each participant completed the assessment in three measurement sessions (baseline, intrasession, and intersession). The accuracy scores at each location and overall accuracy scores were compared across the sessions. The Shapiro-Wilk test indicated that the VASI data were not normally distributed. Intraclass correlation coefficient analysis revealed excellent test-retest reliability of the overall accuracy scores and moderate-to-high reliability of location-specific scores. This was complimented by the low response variability of the overall and location-specific accuracy scores. The Bland-Altman analysis also indicated minimal bias in VASI accuracy scores across the three sessions. It can be concluded from the results that VASI is a reliable tool for assessing spatial-hearing acuity in school-aged children. The high test-retest reliability and ease of portability make the test highly relevant for classroom setups where early diagnosis and intervention of spatial deficits can play a critical role in determining the academic success of school-going children.

Camouflaging the location of a sound source via topology-optimized source-shifter

We demonstrate numerically an inverse design of a structure for camouflaging the location of a sound source as if the sound emanated from a different location. Employing a topology optimization approach used in acoustic–elastic coupled problems, the difference between the sound pressure fields emanating from an actual source and a virtual source, one that is not physically present at the location, is the objective function infimized in camouflaging the sound source. Optimal topologies of elastic structures made of acrylonitrile butadiene styrene were designed for the camouflaging purpose; moreover, no acoustic metamaterials are used. Our metastructures, so-called source-shifters, are expressed at the design stage using a level-set method, which generates sharp interfaces between acrylonitrile butadiene styrene and air. These source-shifters are modeled in finite-element analyses as acoustic–elastic coupled systems and incorporate acoustic fluid–structure interaction. From studies of the underlying camouflaging mechanism and the dependence of camouflaging performance on the distance between actual and virtual locations, we evaluate the effectiveness of our scheme in camouflaging the location of sound sources.

Sense of doubt: inaccurate and alternate locations of virtual magnetic displacements may give a distorted view of animal magnetoreception ability

Virtual magnetic displacements are used to examine the magnetoreceptive ability of animals by changing the local magnetic field to emulate one that exists elsewhere. This technique can be used to test whether animals use a magnetic map. The viability of a magnetic map is dependant upon which magnetic parameters an animal’s coordinate system is composed of, and how sensitive they are to those parameters. Previous research has not considered the degree to which sensitivity can change an animal’s impression of where a virtual magnetic displacement is located. We re-assessed all published studies that use virtual magnetic displacements assuming the highest likely level of sensitivity to magnetic parameters in animals. The vast majority are susceptible to the existence of alternate possible virtual locations. In some cases, this can cause results to become ambiguous. We present a tool for visualising all possible virtual magnetic displacement alternative locations (ViMDAL) and propose changes to how further research on animal magnetoreception is conducted and reported.

Periodic Behavioral Routine Discovery Based on Implicit Spatial Correlations for Smart Home

As the degree of elders’ social activity and self-care ability depreciates, the potential risk for elderly people who live independently increases. The development of assistive services such as smart homes could likely provide them with a safer living environment. These systems collect sensor data to monitor residents’ daily activities and provide assistance services accordingly. In order to do so, a smart home must understand its residents’ daily activities and identify their periodic behavioral daily routine accordingly. However, existing solutions mainly focus on the temporal feature of daily activities and require prior labeling of where sensors are geographically deployed. In this study, we extract implicit spatial information from hidden correlations between sensors deployed in the environment and present a concept of virtual locations that establishes an abstract spatial representation of the physical living space so that prior labeling of the actual location of the sensors is not required. To demonstrate the viability of this concept, an unsupervised periodic behavioral routine discovery method that does not require any predefined location-specific sensor data for a smart home environment is proposed. The experimental results show that with the help of virtual location, the proposed method achieves high accuracy in activity discovery and significantly reduces the computation time required to complete the task relative to a system without virtual location. Furthermore, the result of simulated anomaly detection also shows that the periodic behavioral routine discovery system is more tolerant to differences in the way routines are performed.

Технология сейсмической локации. III. Построение глубинно-скоростной сейсмической модели геологической среды

An original technology for construction of seismic images of high-resolution andaccuracy is proposed. In given article the third part of technology is stated. A new approachto the construction of seismic images is presented here, using stable and unambiguous solutions to several direct kinematic problems of seismic exploration instead of solving oneinverse problem. It is based on the location of the seismic reflection impulse source, which iscarried out by a seismic digital antenna array using a super-resolution location algorithm anda virtual location grid. The accuracy of constructing reflective boundaries is determined bythe specified parameters of the selection and location algorithms used, as well as the nodes ofthe location grid. The seismic location technology has a number of theoretical and practicaladvantages over known seismic imaging technologies.

A real‐time privacy‐preserving scheme based on grouping queries for continuous location‐based services

SummaryWith the advancement of global positioning systems and communication technologies, location‐based services (LBS) have become widely used. However, user location privacy is vulnerable during service exchange, and location‐related queries may result in serious privacy disclosure issues. In this article, considering that attackers may make use of auxiliary information to track a mobile user, we propose a real‐time privacy‐preserving scheme based on the grouping of queries in continuous LBS. In this scheme, we first design the probability density functions to select virtual locations. Then, we group these virtual locations and the query location of the user into several queries. Simultaneously, we send these grouping queries to the LBS server. Following the steps outlined above, grouping queries can be used to conceal the true query. Moreover, the results of security analyses and performance evaluations show that the proposed scheme is effective and secure.

Deep Learning-Enabled File Popularity-Aware Caching Replacement for Satellite-Integrated Content-Centric Networks

In recent years, satellite-integrated content centric networking (SCCN) has become an important solution for the future network with excellent bandwidth savings and file distribution capability in a wide range by the intrinsic caching function. At present, however, the high-speed changes of satellite network topology and coverage make it difficult to predict the file popularity of SCCN network, resulting in a low timeliness. This will lead to low node cache efficiency and bad data distribution performance. To address this issue, in this article, we have proposed a deep learning-enabled file popularity-aware caching replacement mechanism to achieve efficient file distribution in SCCN. In the proposed mechanism, we have developed a virtual location division scheme to keep the return path of content data invariable by remapping the time-varying topology of network into a static topology with virtual nodes. Furthermore, we have put forward a minimum delay file-caching set algorithm to predict the popularity of files in the proposed SCCN via a well-designed deep learning framework, which can find those high-popularity files most worthy of caching. The simulation results verified the proposed method can obviously degrade the access delay of all users and the cache hit ratio of satellite nodes, compared with current strategies, i.e., cache everything everywhere with least recently used, probCache, content-aware placement and discovery, and replacement (APDR), respectively.

Simultaneous LTE Signal Propagation Modelling and Base Station Positioning Based on Multiple Virtual Locations.

In the Long Term Evolution (LTE) system, the Signal Propagation Model (SPM) and the location information of the base stations are required for positioning a smartphone. To this end, this paper proposes a technique for estimating the SPM and the location of the base station at the same time using location-based Reference Signal Received Power (RSRP) information acquired in a limited area. In the proposed technique, multiple Virtual Locations (VLs) for a base station are set within the service area. Signal propagation modelling is performed based on the assumptions that a base station is in each VL and the RSRP measurements are obtained from the corresponding base station. The residuals between the outputs of the estimated SPM and the RSRP measurements are then calculated. The VL with the minimum sum of the squared residuals is determined as the location of the base station. At the same time, the SPM estimated based on the corresponding VL is selected as the SPM of the base station. As a result of the experiment in Seoul, it was confirmed that the positions of seven base stations were estimated with an average accuracy of 40.2 m.

MOCLoc: Emerging Online Collaborative Localization Enhanced by Multidimensional Scaling

In human activity recognition, it is important to first recognize the position of a user. Although numerous fingerprinting schemes have been researched for indoor localization, they work in a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">stand-alone</i> mode without considering the potentials of exploiting multiple requesting users’ online fingerprints. In this paper, we propose an emerging online collaborative localization paradigm to serve the scenarios of multiple users requesting localizations at the same time, which enables a kind of collective calibration by exploiting latent relations in between requesting users in both the signal space and physical space. The proposed scheme is called MOCLoc, which first applies the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">multidimensional scaling</i> (MDS) technique to compute online users’ virtual locations based on their online fingerprints. A new virtual location credibility is next computed for each selected <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">reference point</i> (RP) based on the similarity between its virtual distances and physical distances to other online users. We also compute a collaborative credibility and signal credibility and fuse all three kinds of credibilities to compute a new RP ranking weight that is used to output the user final location. Furthermore, we propose to include a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">device calibration</i> module based on the mean-subtraction fingerprint transformation to differentiate the collaborative calibration process for heterogeneous online devices. Experiments on field measurements validate the effectiveness of the proposed MOCLoc scheme in terms of further reduced localization errors.

Design Principles for Coordination in the Metaverse

The Metaverse represents the next generation of the Internet that, at this instant in time, is still a concept. It is envisioned to provide interconnected experiences that are immersive and varied. This vision challenges both designers and users to understand its possible coordination architecture and develop strategies for participation. One way to understand the concept and affect its instantiation is to take a design science approach that articulates design principles that might guide the exploration of different architectures. We apply concepts related to platforms and business ecosystems as well as ideas about facilitating technologies including choreography and orchestration as ways of blending together experiences, providing transitions between virtual locations. We derive three design principles from an analysis of Metaverse scenarios: Narrative composability, social assortativity, and path discoverability. Thinking through these aspects of design leads to a discussion about the tradeoffs that will face designers of the Metaverse.

Defending Trace-Back Attack in 3D Wireless Internet of Things

With the development of 5G, it is unsurprising that most of the smart devices in the Internet of Things (IoT) will be wirelessly connected with each other in the near future. This kind of lightweight, scalable and green network architecture will be well-received. In a wide variety of IoT application scenarios, sensor nodes deployed in a local space, such as a multistory building, automatically form a distributed 3D wireless IoT and it can be employed to collect and analyze environmental information. Source-location privacy protection is of great importance in these networks and however, most existing schemes focus on only planar distributed networks which are not suitable for the 3D networks. In this paper, we consider a novel trace-back attack for 3D wireless IoT and then design a source-location privacy protection scheme, named DMR-3D, to defend this kind of novel attacks. In DMR-3D, the source node first selects a set of virtual locations to indirectly choose a set of agent nodes based on the cold start sphere structure and the ellipsoid communication pipeline. Then, a sophisticated mechanism is designed based on both the connected graph and Multiple Delaunay Triangulation (MDT) structure of the network to deliver packets from the source node to the destination node via these agent nodes in a relay manner. Analysis and simulation results illustrate that the proposed scheme can effectively protect source-location privacy with a moderate increment of path stretch, time delay and data transmission amount.

Dynamic Virtual Topology Aided Networking and Routing for Aeronautical Ad-Hoc Networks

Aeronautical Ad-hoc Networks (AANETs) have been proposed as the promising complement to terrestrial networks for promoting the global interconnection to provide in-flight network service, emergency communication, vessel traffic service, etc. However, the large network scale of AANETs may induce severe synchronization overhead when the traditional topology-based networking algorithms are adopted. Moreover, the high-dynamic topology and changeable flight routes make the existing position-based routing algorithms suffer loop routing and forwarding failure. Motivated by these problems, this paper aims at developing efficient and low-cost networking and routing algorithms relying on the concept of dynamic virtual topology which organizes the disordered topology of AANETs into a structural and simplified one. The basic idea is that each connected aircraft is assigned with a unique and sequentially increased Virtual Identifier (VID) and thus all the connected aircrafts are organized into a virtual cluster consisting of one trunk and several branches. An event-driven synchronization mechanism is leveraged for maintaining the virtual topology as well as relieving the communication burden imposed by periodical broadcasting. By jointly considering the geographic locations and the virtual locations of aircrafts, we formulate the routing problem in AANETs as a weighted distance minimization problem, and further propose a novel routing algorithm, namely Trunk-Branch Cooperation aided Routing (TBCR) algorithm. Specifically, TBCR employs the geographic greedy forwarding strategy for enhancing its flexibility and boosts the routing efficiency by adopting the loop-free virtual topology based local forwarding. For extending the networking and routing algorithms to the global range, a multi-domain routing solution is also provided. Extensive experimental results show that the proposed Virtual Topology based Networking (VTN) cooperated with TBCR can reduce at least 30% average end-to-end transmission delay in large-scale AANETs and provide more than 90% lower synchronization overhead than the existing solutions.