nils-herrmann/clean_scirepeval huggingface dataset:
Optimal Performance-Efficiency Trade-off for Bag of Words Classification of Road Signs

This paper focuses on road sign classification for creating accurate and up-to-date inventories of traffic signs, which is important for road safety and maintenance. This is a challenging multi-class classification task, as a large number of different sign types exist which only differ in minor details. Moreover, changes in viewpoint, capturing conditions and partial occlusions result in large intra-class variations. Ideally, road sign classification systems should be robust against these variations, while having an acceptable computational load. This paper presents a classification approach based on the popular Bag Of Words (BOW) framework, which we optimize towards the best trade-off between performance and execution time. We analyze the performance aspects of PCA-based dimensionality reduction, soft and hard assignment for BOW codebook matching and the codebook size. Furthermore, we provide an efficient implementation scheme. We compare these techniques to design a fast and accurate BOW-based classification scheme. This approach allows for the selection of a fast but accurate classification methodology. This BOW approach is compared against structural classification, and we show that their combination outperforms both individual methods. This combination, exploiting both BOW and structural information, attains high classification scores (96.25% to 98%) on our challenging real-world datasets.
Effect of internal reflections on the radiation properties and input impedance of integrated lens antennas-comparison between theory and measurements

This paper presents the effect of internal reflections on the beam pattern and input impedance of integrated lens antennas. A silicon lens was designed and manufactured, and measurements were conducted at a frequency of 100 (impedance) and 500 GHz (beam pattern). A frequency-dependence characterization of the beam pattern clearly showed the existence and impact of internal reflections. The measurements confirmed that most of the frequency variations of the beam pattern could be attributed to internal reflections, as predicted by the model. An on-wafer measurement strategy for determining the antenna impedance at millimeter-wave frequencies is presented. The validity of the model was also proven by an excellent match of the input impedance measurements and predictions. Not only the level, but also the oscillation on the impedance curve was predicted accurately. Initial space qualification was performed in the form of thermal cycling.
Identity verification using computer vision for automatic garage door opening

We present a novel system for automatic identification of vehicles as part of an intelligent access control system for a garage entrance. Using a camera in the door, cars are detected and matched to the database of authenticated cars. Once a car is detected, License Plate Recognition (LPR) is applied using character detection and recognition. The found license plate number is matched with the database of authenticated plates. If the car is allowed access, the door will open automatically. The recognition of both cars and characters (LPR) is performed using state-ofthe- art shape descriptors and a linear classifier. Experiments have revealed that 90% of all cars are correctly authenticated from a single image only. Analysis of the computational complexity shows that an embedded implementation allows user authentication within approximately 300ms, which is well within the application constraints.
System architecture for free-viewpoint video and 3D-TV

This paper presents a system architecture of an acquisition, compression and rendering system for 3D- TV and free-viewpoint video applications. We show that the proposed system yields two distinct advantages. First, it achieves an efficient compression of 3D/multi-view video by extending a standard H.264 encoder such that near backward compatibility is retained. Second, the proposed system can efficiently compress both 3D-TV and free- viewpoint multi-view video datasets using the single proposed system architecture.
Scan-Optimized Integrated Lens Antennas

In this paper the scan properties of integrated lens antennas with a quarter-wavelength matching layer are analyzed. For beam scanning on and within a cone, optimum feed positions are determined. It appears that for beam scanning on a cone the elliptical lens is the best choice if a small scan angle is required while the extended hemispherical lens should be used in case of a large scan angle. For beam scanning within a cone it is recommended to select an elliptical lens if a large average directivity is required while the extended hemispherical lens appears to be the best choice if a small variation in the directivity is important.
Reflector focal array based on multi-feed EBG antenna for Ka-band space applications

The demand for multimedia communications via satellite systems have increased considerably in the last years. Normally, the satellite coverage is composed of a hexagonal lattice of many small beams. An example of an experimental satellite coverage named “Agora” is composed of 40 0.65°-diameter spots, using 4 frequency channels in a 4x reuse scheme with the same circular polarization. A first solution which meets the requirements of such a mission (C/I, efficiency, roll-off) is the use of 4 Rx/Tx parabolic reflectors on the same satellite, providing each a family of spots at the same frequency. This solution has the drawback of heavy weight and the challenging accommodation of 4 reflectors on the platform. These 4 reflectors could be replaced by only one, when using a focal array which is capable of generating a specific illumination law (overlapped beams). This focal array could be composed of an active BFN which is, unfortunately, expensive and has moderate RF efficiency. Several studies have shown that overlapped beams could be obtained by using multi-feed EBG antennas [1, 2]. The major problem of these structures is the mutual coupling between different feeds. It was demonstrated recently that suitable filter designs could be connected to each feed [3, 4] in order to ensure the isolation between different channels and also to reconstruct properly the radiation patterns which are otherwise disturbed by the coupling. In  and  it is shown that the use of a matched multi-feed EBG antenna with 2 linear polarizations and 2 frequency channels provides a 4x reuse scheme that simplifies the system architecture. In fact, the use of a matched antenna relaxes the need for the filters to provide matching inside the operating band; they just need to act like a short circuit with the appropriate phase outside their operating band, in order to reconstruct properly the radiation patterns. On the other hand the use of 2 frequency channels reduces the number of required filters (2 filters instead of 4). Finally, linear polarizations are considered in order to prevent the design of bulky filters for circular polarization (6 poles filters with 6 cavities are needed to ensure the transmission of circularly polarized wave and isolation between channels). In this paper, a metallic multi-feed EBG antenna operating in Ka band [29.5–30] GHz is presented, and its performances before and after connecting the filters will be shown. Finally, this antenna is used to illuminate a reflector and the coverage characteristics (C/I) will be given.
On the use of planar EBGs in one dimensional (1D) scanning printed arrays

In a companion paper (N. LLombart et al., 2005) presented in this same conference, the use of planar circularly symmetric (PCS) electromagnetic band-gap (EBG) structures for optimizing the performances of single antenna elements is discussed. A completely planar antenna with 20% of bandwidth which does not suffer from surface wave effects is presented. The key advantage of using this sort of super structures is that they are planar and thus very cheap to manufacture with respect to alternative EBG structures based on vertical pins (P. de Maagt et al., 2003). In this contribution the design efforts are aimed at using planar EBGs to enhance the performances of 1D scanning arrays. This kind of arrays, are becoming increasingly more requested for airborne SAR type of instruments and lower cost naval radars. The purpose of this paper is to provide a step toward the feasibility of fully-integrated planar arrays at very low costs providing a conceptual design. In particular, a design characterized by relatively large bandwidths (BW ap 15%), can be achieved when the arrays are scanned up to 40deg in one dimension only. This design will lead to the manufacture of a phased array demonstrator which do not suffer from surface waves
Radiation performances of a dipole array configuration inserted in a left-handed media

In this work, the radiation improvement achieved when left handed media (LHM) are combined with dipole antennas has been analysed. The behaviour of two dipole antennas in array configuration, when a left handed superstrate and substrate are placed over and under them, has been analysed. Different positions of the dipoles have been studied. Besides, dielectric losses and copper split ring resonators and capacitively loaded strips have been taken into account for different distances between the dipoles in order to analyse their influence on the radiation properties. Simulation results are presented showing high efficiency antennas with enhanced gain patterns.
Test-station for flexible semi-automatic wafer-level silicon photonics testing

Silicon photonics technologies are a particularly attractive solution for developing low-cost optical interconnects with high performance. Imec is developing a silicon photonics technology platform. Developing this platform requires continuous process optimization and design verification, both of which are enabled by the flexible wafer-level test solution that is presented in this paper. The test station enables semi-automatic optical and electro-optical testing of passive and active silicon photonics components and circuits, including waveguides, fiber grating couplers, photodetectors, modulators, filters etc. The measured insertion loss of fiber grating couplers is repeatable to within 0.07dB (6σ), for photodetector responsivity the repeatability is around 0.02A/W (6σ). Calibration procedures have been designed to ensure the long-term reproducibility of measurement results. This is demonstrated with wafer-level measurement data for fiber grating couplers and photodetectors that were gathered over a five-month period. The reproducibility over this period is 0.8dB for the insertion loss and 0.09A/W for the responsivity measurement.
Electrodeposition of Ni-Si Schottky barriers

Electrodeposition is being used to fabricate magnetic microstructures directly on patterned n-type Si wafers of various substrate resistivities. The Ni-Si Schottky barrier is characterized and found to be of high quality for relatively low Si resistivities (1-2 /spl Omega//spl middot/cm), with extremely low reverse leakage. It is shown that a direct correlation exists among the electrodeposition potential, the roughness, and the coercivity of the films. A conductive seed layer or a back contact is not compulsory for electrodeposition on Si with resistivities up to 15 /spl Omega//spl middot/cm. This shows that electrodeposition of magnetic materials on Si might be a viable fabrication technique for magnetoresistance and spintronics applications.
Depth-Image Compression Based on an R-D Optimized Quadtree Decomposition for the Transmission of Multiview Images

This paper presents a novel depth-image coding algorithm that concentrates on the special characteristics of depth images: smooth regions delineated by sharp edges. The algorithm models these smooth regions using piecewise-linear functions and sharp edges by a straight line. To define the area of support for each modeling function, we employ a quadtree decomposition that divides the image into blocks of variable size, each block being approximated by one modeling function containing one or two surfaces. The subdivision of the quadtree and the selection of the type of modeling function is optimized such that a global rate-distortion trade-off is realized. Additionally, we present a predictive coding scheme that improves the coding performance of the quadtree decomposition by exploiting the correlation between each block of the quadtree. Experimental results show that the described technique improves the resulting quality of compressed depth images by 1.5-4 dB when compared to a JPEG-2000 encoder.
An IBM PC based large-vocabulary isolated-utterance speech recognizer

The Speech Recognition Group at IBM Research in Yorktown Heights has designed a real-time, isolated-utterance speech recognizer for natural language with a 5,000-word vocabulary based on the IBM Personal Computer (PC) AT model and two IBM Signal Processors realized in VLSI technology. The enrollment period for a new user is approximately 20 minutes. The basic vocabulary is chosen from the most common words in several collections of documents such as office memoranda and business letters. The system supports spelling and interactive personalization to augment this vocabulary. Signal processing, vector quantization, and acoustic matching algorithms are programmed on the IBM Signal Processors which fit into the PC AT chassis. The PC AT controls the Processors and implements the decoder stack search and the language model, as well as the application-specific interface. The modular architecture of the design is expandable to a 20,000-word vocabulary system by the addition of two more IBM Signal Processors housed in a PC Expansion Unit.
On the technology roadmap of Free-Viewpoint 3DTV receivers

This paper presents the architecture of an innovative 3DTV receiver system, enabling Free-ViewPoint (FVP) interpolation and rendering functionality. We outline the hardware architecture of the receiver, and specify how the design decisions address the extremely high processing requirements of the system. Based on the experience and quantitative data obtained during the receiver prototyping, we present an architecture roadmap for devices with embedded FVP functionality. We identify three major hardware choices for FVP mapping, namely a dedicated hardware unit, FPGA-and GPU solutions, and discuss pros and cons of each choice.
Environmental characterization of industrial fabric for SoftWearAntenna

It was observed that changes in the environmental conditions have direct effect on the electrical parameters. High relative humidity increased the loss tangent. However, keeping the relative humidity constant while decreasing temperature, it was observed to decrease the loss tangent. It seems that the amount of water in the air controls the loss tangent; Decrease in temperature with constant relative humidity condenses some of the water vapor and thus the amount of water in the air is decreased. It was noticed that relative air humidity has a strong influence on permittivity. Increase in relative humidity was seen as an increase in permittivity and vice versa. Additionally, the temperature change affected the absolute value of permittivity. At lower temperatures the permittivity had lower values than at higher temperatures when the relative humidity remained fixed. Here, the absolute amount of water in the air seemed to be connected to this behavior as well.
A supervised approach to the construction of context-sensitive acoustic prototypes

The authors describe a supervised approach to the construction of context-sensitive acoustic prototypes for use in speech recognition systems using allophonic subword hidden Markov models (HMMs). A properly fine partition of the underlying acoustic space(s) is achieved by incorporating contextual supervision to relate the HMM allophonic models to their acoustic manifestations. By decoupling the overall procedure into a clustering phase followed by a pruning phase, it becomes possible to uncover satisfactorily once and for all the general interrelationships between various acoustic subevents, while customizing the acoustic prototypes themselves according to the available training data. This makes for a more efficient utilization of the training sentences, as evidenced by a substantial reduction in the error rate with respect to a baseline system not taking advantage of supervision. The performance of this method is illustrated on an isolated utterance speech recognition task with a vocabulary of 20000 words.<<ETX>>
Evaluation of system configurations for thermoelectric power generation

Recent developments in thermoelectric materials have led to renewed interest in thermoelectric devices for power generation. In a system where a thermoelectric generator uses a finite heat source and sink such as fluid streams, thermodynamic characteristics of the heat source and heat sink are relevant in evaluating the conversion efficiency. Based on the system efficiency equations derived in prior work, an evaluation of a thermoelectric power generation system can be made and its performance can be expressed as a function of both thermoelectric figure of merit and thermal system performance metrics. These dependencies are presented on a performance map. Performance maps reinforce and quantify the suggestion that both thermoelectric material and thermal sciences are crucial to the performance of thermoelectric generators.
Heterogeneous multiprocessor for high definition video

This work presents the heterogeneous multiprocessor capable of processing HDTV material (1920*1080i at 60 Hz) in the domain of motion estimation based TV applications. In particular, it is targeted to the state-of-the-art format conversion and scan-rate conversion functions like de-interlacing and picture-rate up-conversion. The heterogeneous multiprocessor consists of five processors communicating through fifos and shared memories. The highest picture quality level that meets the HDTV real-time performance was enabled by: judicious choice of application task partitioning; right choice of instruction set architecture for the VLIW-based multiprocessor; exploitation of the customized two level memory hierarchy (the search area scratchpad and the region scratchpad). Furthermore, the heterogeneous multiprocessor offers high degree of flexibility: size and aspect ratio of the region and the search area scratchpads; algorithm for selection of the motion vector candidates; algorithm for post-processing of the motion vector field; plethora of interpolation schemes used in motion estimation and compensation offering trade-off between interpolation complexity and number of interpolated pixels in parallel.
Broadband Terahertz Analysis of Energetic Materials—Influence of Crystal Structure and Additives

A detailed broadband analysis of energetic materials using THz time-domain spectroscopy with a bandwidth from 0.2 to 6.4 THz is presented. Dependencies of the resonance features on different sample parameters are evaluated via spectroscopic investigation of several energetic materials (TNT, C4, RDX, PETN, AN) in transmission and reflection experiments. A strong dependency of the resonance features on the manufacturing process of an explosive is observed especially with TNT. The THz measurements of the TNT samples are compared to powder X-ray diffraction measurements. Furthermore, it is observed that additive compounds with a flat frequency response offset the THz reflection of an explosive, but the recognition capability of a resonance feature is not influenced.
Analysis of Magnetoresistance in Arrays of Connected Nano-Rings

We study the anisotropic magnetoresistance (AMR) of a 2-D periodic square array of connected permalloy rings with periodicity of 1 mum combining experimental and computational techniques. The computational model consists of two parts: 1) the computation of the magnetization and 2) the computation of the current density. For 1), we use standard micromagnetic methods. For 2), we start from a potential difference applied across the sample, compute the resulting electric potential, and subsequently the corresponding current density based on a uniform conductivity. We take into account the backreaction of the magnetoresistive effects onto the current density by self-consistently computing the current density and conductivity until they converge. We compare the experimentally measured AMR curve (as a function of the applied field) with the numerically computed results and find good agreement. The numerical data provides insight into the characteristics of the AMR data. Finally, we demonstrate the importance of taking into account the spatial variation of the current density when computing the AMR
Temperature dependence of the permittivity and loss tangent of high-permittivity materials at terahertz frequencies

An analysis including the temperature dependence of the permittivity and loss tangent of three low-cost and high-permittivity materials (zirconium-tin-titanate, alumina, and titanium-dioxide) in the terahertz frequency range is presented. Such dielectric materials find varied applications in microwave and terahertz systems and components. Their effective use under varying environmental conditions or in space applications requires a detailed knowledge about temperature dependencies. Here, measurements using broad-band terahertz time-domain spectroscopy are presented in the temperature range from 10 to 323 K. It is shown that zirconium-tin-titanate and alumina provide a good thermal stability of the permittivity, whereas the permittivity of titanium-dioxide exhibits a strong dependence on the temperature.
Global Illumination Compensation for Background Subtraction Using Gaussian-Based Background Difference Modeling

This paper presents a background segmentation technique, which is able to process acceptable segmentation masks under fast global illumination changes. The histogram of the frame-based background difference is modeled with multiple kernels. The model that represents the histogram at best, is used to determine the shift in luminance due to global illumination or diaphragm changes, such that the background difference can be compensated. Experimental results have revealed that the number of incorrectly classified pixels using global illumination compensation instead of only the approximated median method reduces from 77% to 19% shortly after a fast change. The performance of the proposed technique is similar to state-of-the-art related work for global illumination changes, despite the fact that only luminance information is used. The algorithm is computationally simple and can operate at 30 frames-per-second for VGA resolution on a P-IV 3-GHz PC.
Design of coplanar integrated subMMW receivers by using FDTD lumped element method

A major objective of this work is to show the ability of FDTD to produce accurate designs of MM wave/subMM wave devices in a general way, including the modelling of nonlinear devices. In order to achieve this objective a complete FDTD code has been developed under the scope of this work, including all necessary extension and improvements. The method is then used to study subMM wave coplanar integrated receivers.
Spaceborne submm-wave interferometry

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. The main technical challenges are the very large antenna aperture required for achieving the required spatial resolution (40 folds increase in the distance to the Earth as compared to the LEO) and the necessity for imaging of two-dimensional scanning due to the absence of a relative spacecraft-Earth movement. The requirements derived from this application includes an effective aperture diameter of more than 8 m, which can not be fulfilled by a classical reflector-based instrument. Hence, an interferometric concept has been studied. In this paper a theoretical derivation of the minimum number of receivers that is required is presented along with a discussion on the implementation of such a system in space within a 10-year time frame