1,595 research outputs found
Securing Interactive Sessions Using Mobile Device through Visual Channel and Visual Inspection
Communication channel established from a display to a device's camera is
known as visual channel, and it is helpful in securing key exchange protocol.
In this paper, we study how visual channel can be exploited by a network
terminal and mobile device to jointly verify information in an interactive
session, and how such information can be jointly presented in a user-friendly
manner, taking into account that the mobile device can only capture and display
a small region, and the user may only want to authenticate selective
regions-of-interests. Motivated by applications in Kiosk computing and
multi-factor authentication, we consider three security models: (1) the mobile
device is trusted, (2) at most one of the terminal or the mobile device is
dishonest, and (3) both the terminal and device are dishonest but they do not
collude or communicate. We give two protocols and investigate them under the
abovementioned models. We point out a form of replay attack that renders some
other straightforward implementations cumbersome to use. To enhance
user-friendliness, we propose a solution using visual cues embedded into the 2D
barcodes and incorporate the framework of "augmented reality" for easy
verifications through visual inspection. We give a proof-of-concept
implementation to show that our scheme is feasible in practice.Comment: 16 pages, 10 figure
Unsynchronized 4D Barcodes
We present a novel technique for optical data transfer between public displays and mobile devices based on unsynchronized 4D barcodes. We assume that no direct (electromagnetic or other) connection between the devices can exist. Time-multiplexed, 2D color barcodes are displayed on screens and recorded with camera equipped mobile phones. This allows to transmit information optically between both devices. Our approach maximizes the data throughput and the robustness of the barcode recognition, while no immediate synchronization exists. Although the transfer rate is much smaller than it can be achieved with electromagnetic techniques (e.g., Bluetooth or WiFi), we envision to apply such a technique wherever no direct connection is available. 4D barcodes can, for instance, be integrated into public web-pages, movie sequences or advertisement presentations, and they encode and transmit more information than possible with single 2D or 3D barcodes
Spatial Interference Detection for Mobile Visible Light Communication
Taking advantage of the rolling shutter effect of CMOS cameras in smartphones
is a common practice to increase the transfered data rate with visible light
communication (VLC) without employing external equipment such as photodiodes.
VLC can then be used as replacement of other marker based techniques for object
identification for Augmented Reality and Ubiquitous computing applications.
However, the rolling shutter effect only allows to transmit data over a single
dimension, which considerably limits the available bandwidth. In this article
we propose a new method exploiting spacial interference detection to enable
parallel transmission and design a protocol that enables easy identification of
interferences between two signals. By introducing a second dimension, we are
not only able to significantly increase the available bandwidth, but also
identify and isolate light sources in close proximity
EtÀisyyden huomioiva kaksiulotteinen viivakoodi mobiilikÀyttötapauksiin
Global internet use is becoming increasingly mobile, and mobile data usage is growing exponentially. This puts increasing stress on the radio frequency spectrum that cellular and Wi-Fi networks use. As a consequence, research has also been conducted to develop wireless technologies for other parts of the electromagnetic spectrum â namely, visible light.
One approach of using the visible light channel for wireless communication leverages barcodes. In this thesis, we propose a 2D barcode that can display different information based on the distance between the barcode and the scanner. Earlier research on distance-sensitive barcodes has focused on providing a closer viewer more information as a closer viewer can see more detail. In contrast, we target use cases where a clear physical separation between users of different roles can be made, such as presentation systems.
We evaluate two methods of achieving distance-awareness: color-shifting of individual colors, where a color changes tone at longer distances, and color blending, where two colors blend into a third color at longer viewing distances. Our results show that a modern smartphone is capable of leveraging color-shifting in ideal conditions, but external changes such as ambient lighting render color-shifting unusable in practical scenarios. On the other hand, color blending is robust in varying indoor conditions and can be used to construct a reliable distance-aware barcode.
Accordingly, we employ color blending to design a distance-aware barcode. We implement our solution in an off-the-shelf Android smartphone. Experimental results show that our scheme achieves a clear separation between close and far viewers. As a representative use case, we also implement a presentation system where a single barcode provides the presenter access to presentation tools and the audience access to auxiliary presentation material.Maailmanlaajuinen internetin kĂ€yttö muuttuu yhĂ€ liikkuvammaksi, ja mobiilidatan kĂ€yttö kasvaa eksponentiaalisesti. TĂ€mĂ€ kohdistaa yhĂ€ suurempia vaatimuksia radiotaajuusspektriin, jota mobiili- ja Wi-Fi-verkot kĂ€yttĂ€vĂ€t. NĂ€in ollen tutkijat ovat kehittĂ€neet langattomia teknologioita hyödyntĂ€en myös muita sĂ€hkömagneettisen spektrin osia â erityisesti nĂ€kyvÀÀ valoa.
Yksi nÀkyvÀn valon sovellus langattomassa viestinnÀssÀ ovat viivakoodit. TÀssÀ työssÀ kehitÀmme kaksiulotteisen viivakoodin, joka pystyy vÀlittÀmÀÀn eri tietoa katselijoille eri etÀisyyksillÀ. Aiempi etÀisyyden huomioivien viivakoodien tutkimus on keskittynyt tarjoamaan lÀhellÀ olevalle katselijalle enemmÀn tietoa, koska lÀheinen katselija nÀkee viivakoodin tarkemmin. SitÀ vastoin me keskitymme kÀyttötapauksiin, joissa eri kÀyttÀjÀroolien vÀlillÀ on selkeÀ etÀisyydellinen ero, kuten esimerkiksi esitelmissÀ puhujan ja yleisön vÀlillÀ.
Tarkastelemme kahta menetelmÀÀ: yksittÀisten vÀrien muutoksia etÀisyyden muuttuessa ja kahden vÀrin sekoittumista etÀisyyden kasvaessa. Tulostemme perusteella nykyaikainen Àlypuhelin pystyy hyödyntÀmÀÀn yksittÀisten vÀrien muutoksia ihanteellisissa olosuhteissa, mutta ulkoiset tekijÀt, kuten ympÀristön valaistus, aiheuttavat liian suuria vÀrimuutoksia kÀytÀnnön kÀyttötapauksissa. Toisaalta vÀrien sekoittuminen on johdonmukaista muuttuvassa sisÀympÀristössÀ ja sitÀ voidaan kÀyttÀÀ luotettavan viivakoodin luomisessa.
NÀin ollen me suunnittelemme etÀisyyden huomioivan viivakoodin hyödyntÀen vÀrien sekoittumista. Toteutamme ratkaisumme yleisesti saatavilla olevalle Android-Àlypuhelimelle. Kokeellisten tulostemme perusteella menetelmÀmme saavuttaa selkeÀn erottelun lÀheisten ja kaukaisten katselijoiden vÀlillÀ. EsimerkkikÀyttötapauksena toteutamme myös esitelmÀjÀrjestelmÀn, jossa sama viivakoodi antaa lÀhellÀ olevalle puhujalle nopean pÀÀsyn esitystyökaluihin ja kauempana olevalle yleisölle pÀÀsyn esityksen apumateriaaliin
SBVLC:Secure Barcode-based Visible Light Communication for Smartphones
2D barcodes have enjoyed a significant penetration rate in mobile applications. This is largely due to the extremely low barrier to adoption â almost every camera-enabled smartphone can scan 2D barcodes. As an alternative to NFC technology, 2D barcodes have been increasingly used for security-sensitive mobile applications including mobile payments and personal identification. However, the security of barcode-based communication in mobile applications has not been systematically studied. Due to the visual nature, 2D barcodes are subject to eavesdropping when they are displayed on the smartphone screens. On the other hand, the fundamental design principles of 2D barcodes make it difficult to add security features. In this paper, we propose SBVLC - a secure system for barcode-based visible light communication (VLC) between smartphones. We formally analyze the security of SBVLC based on geometric models and propose physical security enhancement mechanisms for barcode communication by manipulating screen view angles and leveraging user-induced motions. We then develop three secure data exchange schemes that encode information in barcode streams. These schemes are useful in many security-sensitive mobile applications including private information sharing, secure device pairing, and contactless payment. SBVLC is evaluated through extensive experiments on both Android and iOS smartphones
Multiparameter behavioral profiling reveals distinct thermal response regimes in Caenorhabditis elegans.
BackgroundResponding to noxious stimuli by invoking an appropriate escape response is critical for survival of an organism. The sensations of small and large changes in temperature in most organisms have been studied separately in the context of thermotaxis and nociception, respectively. Here we use the nematode C. elegans to address the neurogenetic basis of responses to thermal stimuli over a broad range of intensities.ResultsC. elegans responds to aversive temperature by eliciting a stereotypical behavioral sequence. Upon sensation of the noxious stimulus, it moves backwards, turns and resumes forward movement in a new direction. In order to study the response of C. elegans to a broad range of noxious thermal stimuli, we developed a novel assay that allows simultaneous characterization of multiple aspects of escape behavior elicited by thermal pulses of increasing amplitudes. We exposed the laboratory strain N2, as well as 47 strains with defects in various aspects of nervous system function, to thermal pulses ranging from ÎT = 0.4°C to 9.1°C and recorded the resulting behavioral profiles.ConclusionsThrough analysis of the multidimensional behavioral profiles, we found that the combinations of molecules shaping avoidance responses to a given thermal pulse are unique. At different intensities of aversive thermal stimuli, these distinct combinations of molecules converge onto qualitatively similar stereotyped behavioral sequences
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