Search results for "coding"
showing 10 items of 920 documents
HINTS: A novel approach for realistic simulations of vehicular communications
2012
One of the main challenges in the Vehicular Ad-Hoc Networks (VANETs) research domain is the simulation of vehicular communications using realistic mobility models. Several efforts have been put lately in this purpose; yet, the proposed models are either inappropriate, or carry significant disadvantages. In this paper, we propose a novel approach for realistic simulations in vehicular networks, inspired from the hierarchical video and image compression technique. We developed HINTS (Hybrid Integration of Network and Traffic Simulators), the correspondent platform, engendered from the integration of SUMO, a traffic simulator and NS-3, a network simulator after adding some supplemental modules…
Visual mismatch negativity (vMMN): a prediction error signal in the visual modality
2015
Frontiers in Human Neuroscience, 8
Perceptual uncertainty is a property of the cognitive system
2012
AbstractWe qualify Frost's proposals regarding letter-position coding in visual word recognition and the universal model of reading. First, we show that perceptual uncertainty regarding letter position is not tied to European languages – instead it is a general property of the cognitive system. Second, we argue that a universal model of reading should incorporate a developmental view of the reading process.
Consonant/vowel asymmetries in letter position coding during normal reading: Evidence from parafoveal previews in Thai
2013
Studies have revealed that consonants and vowels serve different roles during linguistic processing. Masked transposed-letter priming effects (i.e., faster word-identification times for words preceded by a transposed-letter than substitution-letter prime) occur for consonants but not for vowels in lexical decision (Perea & Lupker, 2004). Potential differences in letter position coding for consonants and vowels during silent normal reading were investigated in Thai using the boundary paradigm (Rayner, 1975). Thai has a distinctive alphabetic script with vowels taking a relatively subsidiary role in relation to consonants. Parafoveal processing of nonadjacent transposed-letter effects involvi…
Are transposition effects specific to letters?
2010
Recent research has consistently shown that pseudowords created by transposing two letters are perceptually similar to their corresponding base words (e.g., jugde–judge). In the framework of the overlap model (Gomez, Ratcliff, & Perea, 2008), this effect is due to a noisy process in the localization of the “objects” (e.g., letters, kana syllables). In the present study, we examine whether this effect is specific to letter strings or whether it also occurs with other “objects” (namely, digits, symbols, and pseudoletters). To that end, we conducted a series of five masked priming experiments using the same–different task. Results showed robust effects of transposition for all objects, ex…
VoIP end-to-end performance in HSPA with packet age aided HSDPA scheduling
2008
In this paper, we present an enhanced VoIP scheduling for the high speed downlink packet access (HSDPA) in UMTS, which takes the age of the VoIP packet into account. The downlink capacity can be significantly improved by this way, especially for shorter uplink transmission delay. In order to quantify the achievable performance improvement, we present results obtained from extensive system-level uplink and downlink simulations. Inter alia, it is shown that using the proposed scheme can lead to an increase in the downlink cell capacity of up to 16%. By applying the proposed method, the downlink performance can be improved considerably while the uplink performance remains the same, which ensur…
Evaluation of the use of wavefront encoding to reduce depth-induced aberration in structured-illumination microscopy
2018
Three-dimensional imaging is affected by depth-induced spherical aberration (SA) when imaging deep into an optically thick sample. In this work, we evaluate the impact of SA on the performance of incoherent grating-projection structured illumination microscopy (SIM). In particular, we analyze the reduction of the contrast in the structured pattern and compare the reconstructed SIM images for different amounts of SA. In order to mitigate the impact of SA, we implement and evaluate in SIM a wavefront encoded imaging system using a square cubic (SQUBIC) phase mask, an approach shown previously to be successful in conventional microscopy.
Reducing effects of aberration in 3D fluorescence imaging using wavefront coding with a radially symmetric phase mask.
2016
In this work, a wavefront encoded (WFE) imaging system built using a squared cubic phase mask, designed to reduce the sensitivity of the imaging system to spherical aberration, is investigated. The proposed system allows the use of a space-invariant image restoration algorithm, which uses a single PSF, to restore intensity distribution in images suffering aberration, such as sample–induced aberration in thick tissue. This provides a computational advantage over depth-variant image restoration algorithms developed previously to address this aberration. Simulated PSFs of the proposed system are shown to change up to 25% compared to the 0 µm depth PSF (quantified by the structural similarity i…
Energy efficient and distributed resource allocation for wireless powered OFDMA multi-cell networks
2017
In this paper, we investigate the energy efficient resource allocation problem for the wireless powered OFDMA multi-cell networks. In the considered system, the users who have data to transmit in the uplink can only be empowered by the wireless power obtained from multiple base stations (BSs) with a large scale of multiple antennas in the downlink. A time division protocol is considered to divide the time of wireless power transfer (WPT) in the downlink and wireless information transfer (WIT) in the uplink into separate time slot. With the objective to improve the energy efficiency (EE) of the system, we propose the antenna selection, time allocation, subcarrier and power allocation schemes…
Unterstützung klinisch-administrativer Aufgaben durch Personal Digital Assistants (PDAs) - Möglichkeiten und Grenzen
2001
Personal digital assistants (PDAs) are increasingly used by many professional and private users. They replace and combine common calendars, directories, to-do-lists and much more. Supplemented by useful additional software they can assist the clinician in his daily routine work. This concerns typical medical information as well as administrative work but gets more importance with regard to the planned introduction of diagnosis related groups in Germany however. Exact coding of medical performance is essential for this future invoice system. How PDAs can be used convenient in this respect will be shown with examples from our department.