nils-herrmann/clean_scirepeval huggingface dataset:
On the optimal radiation bandwidth of printed slot antennas surrounded by EBGs

This paper describes a design strategy to achieve the maximum bandwidth and efficiency for a printed slot antenna surrounded by EBGs. First the dielectric constant and the thickness of the dielectric slab that guarantees an acceptable front to back radiation ratio is identified. Then electromagnetic bandgap (EBG) structures are designed to achieve the optimal bandwidth (BW) while obtaining high surface wave efficiency in the radiating half space. To achieve this goal the wave interaction between the slot and the EBG structures is investigated in depth and clearly described. For the case of Planar circularly symmetric (PCS) EBGs the maximum of radiation BW is shown to occur when the distance between the central antenna and the EBG is approximately half wavelength of the first surface wave, /spl lambda//sub sw//2.
Performance comparison of a slotted ALOHA DS/SSMA network and a multi-channel narrowband slotted ALOHA network

Throughput, delay, and stability for two slotted ALOHA packet radio systems are compared. One system is a direct-sequence spread-spectrum multiple-access (DS/SSMA) network where each user employs a newly chosen random signature sequence for each bit in a transmitted packet. The other system is a multiple-channel, slotted ALOHA network where each packet is transmitted over a randomly selected channel. Accurate packet success probabilities for the CDMA system are computed using an improved Gaussian approximation technique which accounts for bit-to-bit error dependencies. Average throughput and delay results are obtained for the multiple-channel, slotted ALOHA system and CDMA systems using varying levels of block error correction. The first exit time is computed for both systems and used as a measure of the network stability.<<ETX>>
A Geostationary Atmospheric Sounder for now-casting and short-range weather forecasting

Millimeter and sub-millimeter-wave imagers and sounders are considered for future meteorological and climate observation satellites . The Geostationary Atmospheric Sounder (GAS) , is a development project for an imaging sounder at frequency bands around 53 GHz, 118 GHz, 183 GHz, and 380 GHz. These frequency bands are included to satisfy the user requirements for vertical profiles of temperature and humidity under all weather conditions. The primary advantage of a Geostationary Earth Orbit (GEO) for remote sensing, compared with a Low-Earth Orbit (LEO), is that continuous monitoring is possible over a large area of the Earth's surface and atmosphere. This is desirable for nowcasting, and short range forecasting of rapidly evolving meteorological phenomena.
The inaccuracy of Kubicek's one-cylinder model in thoracic impedance cardiography

The validity of a one- and a two-cylinder model, underlying thoracic impedance cardiography (TIC), was investigated by studying the length dependence of the impedance parameters Z/sub 0/, (dZ/dt)/sub min/, and stroke volume (SV). It can be shown that, within a one-cylinder model, all parameters are directly proportional to the length, whereas, if the volume conduction of the thorax and the neck are modeled separately, Z/sub 0/ and (dZ/dt)/sub min/ are expected to be linear dependent and SV will he nonlinear dependent upon the length. The expectations were compared to results from in vivo measurements. Two electrode arrays were studied, in which the caudal recording electrode position was varied; SV was calculated using Kubicek's equation. Except for small distances, the results showed a nearly linear relation between the parameters and the length. Regression analysis of the linear part revealed statistically significant intercepts (p<0.05). Neither the intercept nor the nonlinear part can be explained by a one-cylinder model, whereas a model consisting of two cylinders serially connected describes the experimental results accurately. Thus SV estimation based on a one-cylinder model is biased due to the invalid one-cylinder model. Corrections for the Kubicek-equation need to be developed in future research using this two-cylinder model.
Leaky Wave Enhanced Feeds for Multibeam Reflectors to be Used for Telecom Satellite Based Links

The use of dielectric super-layers for shaping the radiation pattern of focal plane feeds of a multibeam reflector system is discussed. Using the super-layers, it is possible to reduce the spillover from the reflectors without increasing the dimension of each aperture. The effect has been demonstrated using a realistic array configuration. The experimental demonstration is obtained with configurations which are typical for satellite based multi beam telecommunication links. Thanks to the adoption of a × 4 reuse scheme, based on frequency and polarization orthogonal channels, the measured edge of coverage directivity has improved, with respect to a standard technology case, by 2 dB over an operational bandwidth of about 2%.
Fast scene analysis for surveillance & video databases

In professional/consumer domains, video databases are broadly applied, facilitating quick searching by fast region analysis, to provide an indication of the video contents. For realtime and cost-efficient implementations, it is important to develop algorithms with high accuracy and low computational complexity. In this paper, we analyze the accuracy and computational complexity of newly developed approaches for semantic region labeling and salient region detection, which aim at extracting spatial contextual information from a video. Both algorithms are analyzed by their native DSP computations and memory usage to prove their practical feasibility. In the analyzed semantic region labeling approach, color and texture features are combined with their related vertical image position to label the key regions. In the salient region detection approach, a discrete cosine transform (DCT) is employed, since it provides a compact representation of the signal energy and the computation can be implemented at low cost. The techniques are applied to two complex surveillance use cases, moving ships in a harbor region and moving cars in traffic surveillance videos, to improve scene understanding in surveillance videos. Results show that our spatial contextual information methods quantitatively and qualitatively outperform other approaches with up to 22% gain in accuracy, while operating at several times lower complexity.
Node Interaction in 802.11 based networks with boolean interference

Wireless local area networks (WLANs) have been extensively studied over the past several years. So far, research has primarily focussed on scenarios where all nodes in the network can hear each other. The present paper discusses interaction between nodes in a more complex setting, where nodes may only hear parts of the network. The analysis relies on a Markov process that keeps track of the activity of nodes. Return times and hitting probabilities in this process are related to interaction phenomena in the wireless network and examples are given to illustrate how these can be used to predict network performance. The approximations are validated through simulations.
Estimating hidden Markov model parameters so as to maximize speech recognition accuracy

The problem of estimating the parameter values of hidden Markov word models for speech recognition is addressed. It is argued that maximum-likelihood estimation of the parameters via the forward-backward algorithm may not lead to values which maximize recognition accuracy. An alternative estimation procedure called corrective training, which is aimed at minimizing the number of recognition errors, is described. Corrective training is similar to a well-known error-correcting training procedure for linear classifiers and works by iteratively adjusting the parameter values so as to make correct words more probable and incorrect words less probable. There are strong parallels between corrective training and maximum mutual information estimation; the relationship of these two techniques is discussed and a comparison is made of their performance. Although it has not been proved that the corrective training algorithm converges, experimental evidence suggests that it does, and that it leads to fewer recognition errors that can be obtained with conventional training methods.
Tailoring an Analysis Approach for Developing Evolvable Software Systems: Experiences from Three Case Studies

The analysis, design and implementation of information systems in a changing environment poses significant challenges. Normalized Systems (NS) theory specifically aims to develop software which can cope with these challenges by strictly adhering to theoretically proven design principles and expanding a large part of the code in a highly structured way. One practical implication is that initial prototypes created during the analysis phase can evolve into production-ready applications using incremental refinements. However, little guidance is available on how to perform a (non-technical) functional analysis in a way which leverages the specific advantages of NS software. This paper therefore proposes an NS-specific analysis approach in terms of modeling aspects, project milestones, and stakeholder management. This approach is based upon the inductive analysis of three real-life NS cases performed in different industries. Based on the experiences in these cases, we reflect on the benefits and challenges of our approach. Further, we highlight how our approach can be supplemented by existing analysis and project management frameworks (such as domain-driven design, prototyping and agile development) and how NS software development facilitates the actual realization of these trends.
Bandwidth, efficiency and directivity enhancement of printed antenna performance using planar circularly symmetric EBGs

Planar circularly symmetric (PCS) electromagnetic band-gap (EBG) substrates have been recently proposed to suppress the surface waves in printed technology (Llombart et al., 2004 and 2005). The major advantage of the PCS-EBGs with respect to structures based on vertical pins (de Maagt et al., 2003 and Sievenpiper et al., 1999) is the fabrication simplicity since the dielectric slabs do not need to be perforated. With respect to other planar type of EBG (Coccioli et al., 1999), an advantage is that the surface waves launched by a central source are reduced equally in all radial directions. The motivation of this contribution is to design and measure a prototype which demonstrates the suppression of surface waves by a PCS-EBG of a single antenna printed on a dielectric substrate. Thanks to the presence of the PCS-EBG around the antenna, we obtain an enhancement of the bandwidth, efficiency and directivity performances. The study will present some design considerations for the PCS-EBG itself, and then will proceed with the manufactured and measured antennas. The results explicitly show the advantages in terms of bandwidth and radiation pattern of the proposed EBG substrate. A bandwidth of 20% is achieved without significant surface wave losses.
Leaky Wave Enhanced Feeds for Single Aperture Multi Beam Reflectors

This work is the fourth of a series on the use of super-layers to shape the radiation pattern of each of the feeds composing a focal plane imaging array. Using dielectric or frequency selective surface type of super-layers the spill over from the reflectors is reduced without increasing the dimensions of each aperture. This effect is achieved when the inter-element distance between the feeds is 2.4 wavelengths which is typical for satellite based multi beam telecommunication systems. The shaping of the pattern is obtained with the excitation of a pair (TE/TM) of leaky waves, that radiate incrementally as they propagate between the ground plane and the super-layer. The super-layer can be realized with a single dense dielectric slab (epsivr = 20.25), a double dielectric slab (epsivr = 4.5) or an equivalent frequency selective surface. The maximum edge of coverage enhancement, with respect to reference free space configuration, that can be obtained in these three different cases is equivalent. However, the bandwidth over which the enhancement is maintained depends on how the super-layer is realized. The predicted embedded patterns provide an increase of the edge of coverage gain, with respect to the free space case, of at least 2 dB in an operating bandwidth of ap 1.7%.
IEEE AP-S distinguished lecture

The terahertz (THz) part of the electromagnetic spectrum falls between the lower frequency millimetre wave region and, at higher frequencies, the far-infrared region. The frequency range extends from 0.1 THz to 10 THz, where both these limits are rather loose. As the THz region separates the more established domains of microwaves and optics, a typical THz technique will incorporate aspects of both realms, and may even draw on the best of both. The two bounding parts of the spectrum also yield distinct sets of methods of generating and detecting THz waves. These approaches can thus be categorised as having either microwave or optical/photonic origins. As a result of breakthroughs in technology, the THz region is finally finding applications outside its traditional heartlands of remote sensing and radio astronomy. Extensive research has identified many attractive uses and has paved the technological path towards flexible and accessible THz systems. Examples of novel applications include medical and dental imaging, gene theory, communications and detecting the DNA sequence of virus and bacteria. The presentation will discuss the range of THz applications and will present the components and systems that are utilised for the frequency region.
Input impedance of integrated elliptical lens antennas

An efficient method is presented for prediction of the input impedance of integrated elliptical lens antennas, excited by a focal radiator which consists of either a resonant slot or a slot-coupled patch. Simple equivalent networks are derived from this method which accounts for effects of multiple reflections inside the lens, which is useful for CAD purposes. Numerical results are presented to validate the equivalent networks. Furthermore, it is shown that these internal reflections significantly affect the input impedance of the primary source.
Complexity reduction of wavelet codecs through modified quality control

Integer-to-integer wavelets are employed for low-complexity image encoders in embedded applications and used in combination with wavelet coefficient coders, such as EZW, SPIHT, SPECK and TSSP. In scalable coders bitstream creation is computationally expensive when individual coefficients are manipulated. In this paper, we study two options that move the quality control to earlier stages in the encoding process to alleviate this complexity problem: (1) to stage one of the TSSP and (2) to the integer wavelet transform. By inserting special functions based on premature bit-plane dropping, we effectively implement a quality-control step prior to the coefficient coding. For a typical usage scenario with full HD images, with option (1) we achieve an improvement of the processing speed of TSSP by 28%, while retaining the original bitstream and thus the ratedistortion performance. Furthermore, we have found that option (2) is generically applicable to other bit-plane based codecs, while offering nearly the same processing speed.
III-V/silicon-on-insulator photonic integrated circuit for fiber-to-the-home central office transceivers in a point-to-point network configuration

We describe the realization of III-V/silicon-on-insulator photonic integrated circuits for Fiber-to-the-Home transceivers in the central office. Above 0.4A/W responsivity is obtained in the 1310nm band (with polarization dependent loss below 0.5dB). Crosstalk from the 1490nm/1550nm wavelength channel is below −20dB.
3D colored model generation based on multiview textures and triangular mesh

Three-dimensional colored models are of great interests to many fields. With the growing availability of inexpensive 3D sensing systems, it is easy to obtain triangular mesh and multiview textures. These range and vision data can be fused to provide such 3D colored models. However, low-cost sensing generates various noise components involving low-quality texture, errors in calibration and mesh modeling. Our primary objective is to establish high-quality 3D colored models on the basis of mesh and textures, while considering the noise types and characteristics. In this paper, we contribute in two ways. The first contribution is a point-based algorithm to color 3D models, where 3D surface points are used as primitives to process and store color information. The algorithm features three novel techniques: (a) accurate depth image estimation, (b) adaptive 3D surface point upsampling and (c) texture blending using those points. The algorithm provides colored models as dense colored point clouds, which can be rendered with various standard techniques for visualization. Our second contribution is an algorithm for textured model rendering, where blended textures are generated and mapped onto the mesh. The experimental results show that our algorithms efficiently provide high-quality colored models and enable visually appealing rendering, while being tolerant to errors from data acquisition. We also quantify the efficiency of our point upsampling algorithm with novel metrics assessing the influence of the 3D points.
Multonic Markov word models for large vocabulary continuous speech recognition

A new class of hidden Markov models is proposed for the acoustic representation of words in an automatic speech recognition system. The models, built from combinations of acoustically based sub-word units called fenones, are derived automatically from one or more sample utterances of a word. Because they are more flexible than previously reported fenone-based word models, they lead to an improved capability of modeling variations in pronunciation. They are therefore particularly useful in the recognition of continuous speech. In addition, their construction is relatively simple, because it can be done using the well-known forward-backward algorithm for parameter estimation of hidden Markov models. Appropriate reestimation formulas are derived for this purpose. Experimental results obtained on a 5000-word vocabulary natural language continuous speech recognition task are presented to illustrate the enhanced power of discrimination of the new models.
Real-time scalable video codec implementation for surveillance

In this paper, we discuss the design and real-time implementation of a Scalable Video Codec (SVC) for surveillance applications. We present a complexity-scalable temporal wavelet transform and the implementation of a multi-level 2D 5/3 wavelet transform, using the lifting framework. We have employed SIMD (Single Instruction Multiple Data) and DMA (Direct Memory Access) techniques, where the proposed process of background DMA transfers is so effective, that the ALUs are always supplied with input data. We have realized the execution of a 4-level transform at 4CIF (CCIR-601) broadcast resolution in 3.65 Mcycles, including memory stalls, on a TMS320DM642 DSP. At a clock rate of 600 MHz, this translates to more than 160 transforms per second. For our complete SVC, we achieve a frame rate of 12.5–15 fps depending on scene activity.
Security moving from database systems to ERP systems

Usage of Information Systems moves from a central database system with many application programs to fully integrated systems with which an enterprise is handling many of its information and communication problems (ERP). In this paper we study how these systems deal with the security issue; we see that on the one hand by moving the security from the database level to the ERP level, advantages by having centrally defined and maintained security rules get lost, on the other hand it is possible to exploit WorkFlow Management (WFM) techniques to define security procedures more properly, such that the "separation of duty" principle can be applied. We demonstrate this on the tricky security rules for the security employees themselves.
1-D Scanning Arrays on Dense Dielectrics Using PCS-EBG Technology

We show how the design of integrated arrays can significantly benefit from planar circularly symmetric (PCS) electromagnetic band gap (EBG) structures. Using this technology, a phased array that scans up to 40deg in one dimension and that is characterized by relatively large bandwidth (BWap15%) is designed, manufactured and tested. The specific advantages coming from the use of PCS-EBGs are two fold. On one hand the losses associated to surface waves are significantly reduced. On the other hand each element of the array has a larger effective area that leads to a higher gain for the complete array when compared with a standard technology. Additional benefits are the low cross-polarization levels, the good front to back ratio considering that the antenna does not include a backing reflector, and the low profile
Global and locally adaptive warped motion compensation in video compression

Real motion is often complex, and cannot always be sufficiently described by a translational model for the purpose of video coding. Translational motion models can only map a rectangular to a rectangular of the same size in a reference frame, but real motion observed in videos often go beyond that. For example, motion due to camera shake, panning and zoom might require transformations that support shearing, scaling, rotation and changes in aspect ratio. In order to handle these instances adequately for video encoding, we introduce two coding modes — a global motion mode and a locally adaptive warped motion mode, that make use of affine and/or homographic projections to more accurately describe and predict complex motion. These warped modes respectively capture global motion computed at the frame level, or local motion computed at the block level based on local motion statistics. We pay special attention to efficient SIMD friendly decoder-side warping operations to make these tools practically useful. Together, these techniques prove to yield considerable coding gains on standard test sets.
Sex Ratio and Gamete Production in American Oysters Exposed to Tributyltin in the Laboratory

Adults oysters (Crassostrea virginica) were exposed to TBT at concentrations of 0 (control), 50, 100, 500, and 1000 ng/l for 8 weeks, Initially of indeterminate sex, all were sexually mature after 2 weeks at 25°C at all TBT concentrations and remained mature throughout the study. Gametes obtained by stripping were mature and generally fertilizable when crossed with gametes from a reference population. The only effect observed which was attributable to TBT was mortality in the high exposure concentration following a brief elevation in concentration due to a failure of water flow.
Background Estimation and Adaptation Model with Light-Change Removal for Heavily Down-Sampled Video Surveillance Signals

This paper describes a background-subtraction system with light change-detection which works on a luminance QCIF-size video signal for surveillance applications. The new proposed pixel background model is controlled by a statistical threshold and is robust for cluttered background and small object motions. Moreover, (or light-change detection, we introduce temporal prediction of pixel values to estimate trends while quickly adapting to scene changes to facilitate a very sensitive detection of moving targets. Experiments show that a local contrast enhancement applied prior to down-sampling improves detection sensitivity, arid combined with the shifted sealed difference and me Wronskian determinant operators provides the best background/foreground detection.