Video Manipulation Techniques for the Protection of Privacy in Remote Presence Systems

Systems that give control of a mobile robot to a remote user raise privacy concerns about what the remote user can see and do through the robot. We aim to preserve some of that privacy by manipulating the video data that the remote user sees. Through two user studies, we explore the effectiveness of different video manipulation techniques at providing different types of privacy. We simultaneously examine task performance in the presence of privacy protection. In the first study, participants were asked to watch a video captured by a robot exploring an office environment and to complete a series of observational tasks under differing video manipulation conditions. Our results show that using manipulations of the video stream can lead to fewer privacy violations for different privacy types. Through a second user study, it was demonstrated that these privacy-protecting techniques were effective without diminishing the task performance of the remote user.Comment: 14 pages, 8 figure

Quasi-continuous frequency tunable terahertz quantum cascade lasers with coupled cavity and integrated photonic lattice

We demonstrate quasi-continuous tuning of the emission frequency from coupled cavity terahertz frequency quantum cascade lasers. Such coupled cavity lasers comprise a lasing cavity and a tuning cavity which are optically coupled through a narrow air slit and are operated above and below the lasing threshold current, respectively. The emission frequency of these devices is determined by the Vernier resonance of longitudinal modes in the lasing and the tuning cavities, and can be tuned by applying an index perturbation in the tuning cavity. The spectral coverage of the coupled cavity devices have been increased by reducing the repetition frequency of the Vernier resonance and increasing the ratio of the free spectral ranges of the two cavities. A continuous tuning of the coupled cavity modes has been realized through an index perturbation of the lasing cavity itself by using wide electrical heating pulses at the tuning cavity and exploiting thermal conduction through the monolithic substrate. Single mode emission and discrete frequency tuning over a bandwidth of 100 GHz and a quasi-continuous frequency coverage of 7 GHz at 2.25 THz is demonstrated. An improvement in the side mode suppression and a continuous spectral coverage of 3 GHz is achieved without any degradation of output power by integrating a π-phase shifted photonic lattice in the laser cavity

Activity fragmentation, ICT and travel : An exploratory path analysis of spatiotemporal interrelationships

This paper focuses on the interrelationships between ICT, activity fragmentation and travel behaviour. The concept of fragmentation relates to how activities are spatiotemporally reorganized, by subdividing activities into smaller components that are then performed at different times and/or locations, in connection with ICT use. The association between ICT, activity fragmentation and travel relationships remains uncharted. Based on a two-day Dutch communication-activity-travel diary different associations between ICT use, paid work spatiotemporal fragmentation indicators and frequency of travel are specified and tested with Path Analysis Modelling accounting for sociodemographic and land use factors. The results demonstrate that the interrelationships between fragmentation, ICT and travel are quite complex. ICT and fragmentation apparently have a reciprocal relationship with mobile ICT use influencing the degree of spatial fragmentation whereas the usages of sedentary ICT are influenced by the degree of temporal fragmentation. Person-ICT attributes and ICT use mediate the participation in non-work activities, and can replace work and non-work travel. Fragmentation reduces work trips but at the same time restricts non-work personal travel possibilities and can reallocate time for leisure activity and travel

Activity fragmentation, ICT and travel : An exploratory path analysis of spatiotemporal interrelationships

This paper focuses on the interrelationships between ICT, activity fragmentation and travel behaviour. The concept of fragmentation relates to how activities are spatiotemporally reorganized, by subdividing activities into smaller components that are then performed at different times and/or locations, in connection with ICT use. The association between ICT, activity fragmentation and travel relationships remains uncharted. Based on a two-day Dutch communication-activity-travel diary different associations between ICT use, paid work spatiotemporal fragmentation indicators and frequency of travel are specified and tested with Path Analysis Modelling accounting for sociodemographic and land use factors. The results demonstrate that the interrelationships between fragmentation, ICT and travel are quite complex. ICT and fragmentation apparently have a reciprocal relationship with mobile ICT use influencing the degree of spatial fragmentation whereas the usages of sedentary ICT are influenced by the degree of temporal fragmentation. Person-ICT attributes and ICT use mediate the participation in non-work activities, and can replace work and non-work travel. Fragmentation reduces work trips but at the same time restricts non-work personal travel possibilities and can reallocate time for leisure activity and travel

Anything, anywhere, anytime? Developing indicators to assess the spatial and temporal fragmentation of activities

Developments in transportation and information and communication technologies (ICTs) have facilitated the process labeled activity fragmentation. In this process, the weakened associations between activity, time, and place that ICTs made possible facilitate the disintegration of activities into smaller subtasks, which can then be performed at different times and at different locations. However, until now discussion of the fragmentation of activity hypothesis has been limited to the theoretical domain and largely absent from the empirical domain. In the study reported here we connect both domains by (1) developing a set of measures of activity fragmentation and (2) applying them to study the fragmentation of the activity of paid work using combined activity, travel, and communication diary data collected in the Netherlands in 2007 in order to assess the performance of these indicators. The results show that the indicators differentiate between the multiple facets of activity fragmentation (such as the number, dispersion, and configuration of fragments). The preliminary analyses also suggest that, although the temporal fragmentation of activities appears to be or to have become more common, spatial activity fragmentation is rather limited. © 2011 Pion Ltd and its Licensors

Anything, anywhere, anytime? Developing measurement instruments to assess the spatial and temporal fragmentation of activities

Developments in transportation and information and communication technologies (ICTs) have facilitated the process labeled activity fragmentation. In this process, the weakened associations between activity, time and place that ICTs made possible facilitate the disintegration of activities into smaller subtasks, which can then be performed at different times and at different locations. However, until now discussion of the fragmentation of activity hypothesis has been limited to the theoretical domain and largely absent from the empirical domain. In the study reported here we connect both domains by (1) developing a set of measures of activity fragmentation and (2) applying them to study the fragmentation of the activity of paid work using combined activity, travel and communication diary data collected in the Netherlands in 2007 in order to assess the performance of these indicators. The results show that the indicators differentiate between the multiple facets of activity fragmentation (such as the number, dispersion and configuration of fragments). The preliminary analyses also suggest that, although the temporal fragmentation of activities appears to be or to have become more common, spatial activity fragmentation is rather limited

Anything, anywhere, anytime? Developing indicators to assess the spatial and temporal fragmentation of activities

Developments in transportation and information and communication technologies (ICTs) have facilitated the process labeled activity fragmentation . In this process, the weakened associations between activity, time, and place that ICTs made possible facilitate the disintegration of activities into smaller subtasks, which can then be performed at different times and at different locations. However, until now discussion of the fragmentation of activity hypothesis has been limited to the theoretical domain and largely absent from the empirical domain. In the study reported here we connect both domains by (1) developing a set of measures of activity fragmentation and (2) applying them to study the fragmentation of the activity of paid work using combined activity, travel, and communication diary data collected in the Netherlands in 2007 in order to assess the performance of these indicators. The results show that the indicators differentiate between the multiple facets of activity fragmentation (such as the number, dispersion, and configuration of fragments). The preliminary analyses also suggest that, although the temporal fragmentation of activities appears to be or to have become more common, spatial activity fragmentation is rather limited.

Using X-Rays for Multiphase Flow Visualization

Gas-liquid, gas-solid, liquid-solid, and gas-liquid-solid multiphase flows are difficult to visualize, characterize, and quantify because the systems are typically opaque. Invasive or noninvasive measurement methods are typically used for determining internal flow and transport characteristics of these complex flows. The difficulty with invasive methods is that they can alter the internal flow of a multiphase system causing interference with realistic process measurements. X-ray imaging provides one family of noninvasive measurement techniques used extensively for product testing and evaluation of static objects with complex structures. These techniques have been extended to visualize dynamic systems, such as those which characterize multiphase flows. This paper will describe a new X-ray flow visualization facility for large-scale multiphase flows. X-ray radiography and X-ray computed tomography of static and dynamic systems will be used to demonstrate system capabilities. Radiographic images will show bread dough rising, objects falling in a liquid, large bubbles rising in a 32 cm ID column of water, and operation of a 32 cm ID bubble column. X-ray computed tomography of a large static object will demonstrate visualization capabilities. X-ray computed tomography of a multiphase flow in a 32 cm bubble column will show local time-averaged gas holdup values for various operating conditions. Finally, challenges associated with X-ray stereographic imaging to capture time-resolved dynamic events will be outlined.This is a conference proceeding from ASME 2005 Fluids Engineering Division Summer Meeting 2 (2005): 415, doi:10.1115/FEDSM2005-77359. Posted with permission.</p

Swept-frequency feedback interferometry using terahertz frequency QCLs: a method for imaging and materials analysis

The terahertz (THz) frequency quantum cascade laser (QCL) is a compact source of high-power radiation with a narrow intrinsic linewidth. As such, THz QCLs are extremely promising sources for applications including high-resolution spectroscopy, heterodyne detection, and coherent imaging. We exploit the remarkable phase-stability of THz QCLs to create a coherent swept-frequency delayed self-homodyning method for both imaging and materials analysis, using laser feedback interferometry. Using our scheme we obtain amplitude-like and phase-like images with minimal signal processing. We determine the physical relationship between the operating parameters of the laser under feedback and the complex refractive index of the target and demonstrate that this coherent detection method enables extraction of complex refractive indices with high accuracy. This establishes an ultimately compact and easy-to-implement THz imaging and materials analysis system, in which the local oscillator, mixer, and detector are all combined into a single laser