nils-herrmann/clean_scirepeval huggingface dataset:
Terahertz Antenna Technology and Verification: Herschel and Planck - A Review

One of the aspects that the space and terrestrial terahertz imaging systems have in common is that they require state-of-the-art technology to achieve their ambitious goals. Although technology is advancing at a rapid pace in this frequency range, the requirements for these systems go well beyond what is currently available such that there are also no standards or calibration reference sources in this field. This paper describes the novel procedures that have been implemented to assess the “in-orbit” RF performance of two European Space Agency (ESA) satellites using on-ground verification procedures. These consisted of using several different measurement techniques at both ambient and cryo-temperatures and software model correlation to be able to predict the final performance. ESA's Herschel and Planck observatories are used as an example to highlight some of the hurdles that had to be overcome for the challenging task of flight-performance verification at (sub)millimeter-wave frequencies. Significant advances have been achieved despite the lack of internationally agreed procedures and practices pushing terahertz reflector and instrument technologies to new limits. This is a review paper and has been written on behalf of the large scientific, engineering, and management teams that were involved over many years in the development, production, testing, and operation of the two spacecraft.
A Grating-Coupler-Enabled CMOS Photonics Platform

We have developed a silicon photonics platform that allows monolithic integration with electronic circuits in a CMOS-compatible process. In this platform, vertical couplers are found to be a superior solution compared to traditional edge-coupling techniques. Grating couplers are an essential element in developing the optical wafer-scale test infrastructure, which in turn, enables the development of the photonic device library. The photonic devices were assembled into a 4 × 10 Gb/s transceiver die that also contains modulator drive, control, and receive electronics.
A sub-millimetre wave airborne demonstrator for the observation of precipitation and ice clouds

Sub-millimetre remote sensing instruments can provide critical information on cirrus clouds and an alternative way of measuring precipitation with a much smaller antenna than those which microwave sensors currently use. Two satellite concepts CIWSIR and GOMAS were proposed as ESA Earth Explorer missions; these were not funded, however they were recommended for an aircraft demonstrator. ESA studies have been performed to identify the optimum instrument and platform to demonstrate these satellite concepts. This paper reports on one of these preparatory activities; the design of a sub-millimetre wave airborne demonstrator for both ice cloud and precipitation observations which will be able to prove the feasibility of the scientific principles of both satellite missions. The paper will describe the derivation of the demonstrator requirements, consideration of the available platform and instrument options, the design of the selected concept, performance prediction and the outline of a proof of concept flight campaign. It will present the outcome of the study which describes a demonstrator design based upon the new Met Office International Sub-Millimetre Airborne Radiometer (ISMAR).
Multiband EBG navigation antenna

EBG superstrate based antenna designs can find its applications in Geosynchonous Satellite Navigation (GSN) System Antennas, since they allow to reduce the number of radiating elements while keeping the required high directivity and circular polarization. Their use will considerably simplify the feeding network and simultaneously reduce the antenna mass and volume. A dual layer EBG superstrate which can be easily tuned to the desired frequencies is presented in this paper. The design has been optimized to comply with the navigation antenna requirements of Wide Area Augmentation System (WAAS) application in L1 and L2 bands.
New DCT computation algorithm for video quality scaling

The application of video coding systems, such as MPEG, in portable systems like organizers and mobile phones can be scaled down to a reduced complexity that matches with the desired video quality and/or display. A new DCT computation algorithm is presented, based on an analysis for optimizing the number of computations involved at each computing stage, using existing fast DCT calculation algorithms. The analysis is used to scale down the video quality, thereby lowering the computing power and resource usage. Compared to a diagonally oriented computation of coefficients that matches with the conventional MPEG scanning, a 2 to 4 dB SNR improvement is obtained when scaling down the video quality to half the computing resources.
MPEG-2 compliant trick play over a digital interface

Current analog and digital tape based video recorders support trick play mode such as fast search and slow- motion, it is desirable that non-tape based systems have at least the same functionality as the already existing systems. This paper presents an experimental trick-play technique that allows visual search on a remotely locate disk-based storage system connected to a digital TV via a digital interface that resembles the performance of tape-based recorders. Our concept is based avoiding intermediate transcoding of the video signal, but instead re-using the recorded MPEG-2 encoded video. This allows generation of fast search modes in forward and reverse direction, as well as slow-motion in forward direction. A special is introduced, to overcome annoying motion judder when interlaced pictures are re-displayed twice or more. Our experimental results show that the proposed reduced refresh-rate mechanism indeed shows better visual performance than a conventional system without additional processing and it copes with various real-time constraints such as bandwidth, disk seek-rate and CPU load.
Training-free moving object detection system based on hierarchical color-guided motion segmentation

We present a moving object detection system for surveillance based on Hierarchical Color-guided Motion segmentation (HiCoMo). The HiCoMo system does not require training and consists of two main stages: (1) hierarchical color-guided motion segmentation, and (2) motion-based verification. The first stage is a hierarchical segmentation framework, where at each level a balance is made between static and temporal features. So that groups of pixels develop into semantic object segments. In the second stage, these object segments are further analyzed in terms of motion saliency and consistency, in order to finalize the object detection results. Our proposed system is tested on real-life surveillance videos containing various scenarios. The detection results outperform a state-of-the-art training-free moving object detection algorithm in recall (90.2% compared to 81.6%) while having a competitively promising precision (96.5% compared to 97.4%). The system has a generic nature and real-time implementation potential, which makes it applicable to various applications of computer vision.
Enhanced feeds in focal plane imaging array systems: Off focus configurations

The performances of focal plane arrays that implement multi-beam coverage from a single reflector antenna are usually reduced by conflicting requirements on the feed elements. Dense packing is required to minimize the beam separation, while typically large apertures provide the high feed directivity which in turn translates in low spill over losses from the reflector. In this paper the use of a dielectric super-layer is proposed to shape the radiation pattern of each feed so that the spill over from the reflector is reduced without increasing the dimensions of each aperture. A prototype with 19 wave-guides arranged in a hexagonal lattice has been designed. The simulated embedded patterns provide an increase of the edge of coverage gain, with respect to the free space case, of at least 1dB in an operating bandwidth of ap6%. Moreover when a frequency and polarization reuse scheme is adopted the increase in the edge of coverage is 2.1 dB leading to a fully efficient use of the reflector.
Optoelectronic integration for reduced power dissipation in optical interconnect

Increasing data interconnect densities and rates drive the requirements for optical high-speed interfaces to ASICs (e.g. network switches, routers, CPU's). In contemporary implementations, as illustrated in Figure 1a, optical transceivers (such as SFP and QSFP modules and AOCs) are located at the card edge. In such an architecture increasing data rates aggravate electrical signal integrity issues due to reflections at optical connectors and losses (dielectric and skin-effect) in the relatively long traces on the card PCBA connecting the electrical pads of the switch chip with the fingers of the transceiver module. To overcome those challenges, advanced (power hungry) electrical I/Os (re-timers, equalizers,) on the ASIC and the optical transceivers are required. Also advanced (costly) PCB materials may be needed. An approach to reduce those signal integrity problems is to reduce the distance between the optical transceivers and the ASIC by moving the transceivers from the board edge to the inside of the shelf as illustrated in Figure 1b. Here the optical signals are routed to the front panel by means of optical fibers. As an additional benefit, embedding the transceivers in the card may increase the achievable density at the card edge. However, it also adds more stringent reliability and thermal management requirements for the optical transceivers. An example is the IBM Power 775 System where transceivers are located around a HUB ASIC . The most ideal solution has the ASIC and the optical transceivers integrated or co-packaged as shown in Figure.2c. This approach virtually eliminates the signal integrity challenges and enables the highest interconnect density.
Robust classification system with reliability prediction for semi-automatic traffic-sign inventory systems

Inventories of traffic signs are acquired from street-level images in a semi-automated fashion, employing object detection and classification techniques. This is a challenging task, as signs are captured from different viewpoints and under various weather conditions. Furthermore, many similar signs exist, only differing in minor details, and moreover, sign-like objects occur frequently. Consequently, current state-of-the-art systems are unable to reach the required quality level, implying the need for manual corrections. This involves checking all classification results to correct the small minority of misclassifications. This paper presents a classification approach aiming at both high recognition scores and predicting the reliability of the classification output, enabling selective manual intervention. Two reliability prediction methods are compared, analyzing either the classifier scores, or matching the input samples with predefined templates. Large-scale experiments performed for three sign classes, each containing numerous sign types, show that over 80% of the correctly classified results can be marked as reliable, while not marking any misclassifications as reliable. Hence, our research shows that a reliable prediction is possible and that manual invention can be concentrated to the about 25% remaining samples only. Overall, 92.7% of the 8, 159 signs are classified correctly.
CARAT: a Toolkit for Design and Performance Analysis of Component-Based Embedded Systems

Solid frameworks and toolkits for design and analysis of embedded systems are of high importance, since they enable early reasoning about critical properties of a system. This paper presents a software toolkit that supports the design and performance analysis of real-time component-based software architectures deployed on heterogeneous multiprocessor platforms. The tooling environment contains a set of integrated tools for (a) component storage and retrieval, (b) graphics-based design of software and hardware architectures, (c) performance analysis of the designed architectures and, (d) automated code generation. The cornerstone of the toolkit is a performance analysis framework that automates composition of the individual component models into a system executable model, allows simulation of the system model and gives design-time predictions of key performance properties like response time, data throughput, and usage of hardware resources. The efficiency of this toolkit was illustrated on a car radio navigation benchmark system
The influence of pulsatile flow on blood resistivity in impedance cardiography

The purpose of the study was to investigate the resistivity change over the cardiac cycle. This is important for the correct application of thoracic impedance cardiography (TIC). The ratio of spatial mean velocity over the vessel radius of the ascending and descending aorta of two female and eight male subjects (age ranging from 23 to 69 years) were measured in supine position using MRI. Based on Visser's (1989) equation the relative resistivity change was calculated. In all subjects the authors found a change of less than 15%, which is smaller than rigid tube experiments predicted. However, the peak resistivity change occurs at the same time as the peak in the impedance signal. Thus, the effects of resistivity changes on stroke volume calculation in TIC needs further investigation.
Automatic assessment of informative frames in endoscopic video

Recently, studies have proven the feasibility of Computer-Aided Detection (CAD) systems for the early detection of esophageal cancer, exploiting the high-quality visual information of HD endoscopy. However, many frames in an endoscopic video are not suited for the detection of cancer, as they are out-of-focus or contaminated by intestinal juices and/or specular reflections. The analysis of useless low-quality frames should be avoided and may also lead to spurious (false) detections. In this paper, we present a novel automated method for the assessment and selection of informative frames in endoscopic videos. This method can serve as a pre-processing step for a CAD system. The proposed method distinguishes informative and noninformative frames with an area under the curve of 97.4%, which significantly outperforms state-of-the-art algorithms.
Objective quality analysis for free-viewpoint DIBR

Interactive free-viewpoint selection applied to a 3D multi-view video signal is an attractive feature of the rapidly developing 3DTV media. In recent years, significant research has been done on free-viewpoint rendering algorithms which mostly have similar building blocks. In this paper, we analyze the four principal building blocks of most recent rendering algorithms and their contribution to the overall rendering quality. We have discovered that the rendering quality is dominated by the first step, Warping which determines the basic quality level of the complete rendering chain. The third step, Blending, is a valuable step which further increases the rendering quality by as much as 1.4 dB while reducing the disocclusions to less than 1% of the total image. Varying the angle between the two reference cameras, we notice that the quality of each principal building block degrades with a similar rate, 0.1–0.3dB/degree for real-life sequences. While experimenting with synthetic data of higher accuracy, we conclude that for developing better free-viewpoint algorithms, it is necessary to generate depth maps with more quantization levels so that the Warping and Blending steps can further contribute to the quality enhancement.
Speech recognition with continuous-parameter hidden Markov models

The acoustic-modelling problem in automatic speech recognition is examined from an information theoretic point of view. This problem is to design a speech-recognition system which can extract from the speech waveform as much information as possible about the corresponding word sequence. The information extraction process is factored into two steps: a signal-processing step which converts a speech waveform into a sequence of informative acoustic feature vectors, and a step which models such a sequence. The authors are primarily concerned with the use of hidden Markov models to model sequences of feature vectors which lie in a continuous space. They explore the trade-off between packing information into such sequences and being able to model them accurately. The difficulty of developing accurate models of continuous-parameter sequences is addressed by investigating a method of parameter estimation which is designed to cope with inaccurate modeling assumptions.<<ETX>>
A Broadband 835–900-GHz Fundamental Balanced Mixer Based on Monolithic GaAs Membrane Schottky Diodes

The development of a 835-900-GHz biasable fundamental balanced mixer using planar GaAs Schottky diodes is presented. The monolithic microwave integrated circuit integrates two planar Schottky anodes in a balanced configuration, stripline filtering elements, and on-chip capacitor on a thin GaAs membrane. At 850 GHz, double side-band (DSB) mixer noise temperature of 2660 K and conversion loss of 9.25 dB are measured, respectively, at room temperature. When the mixer is cooled to 120 K, the DSB mixer noise temperature and conversion loss improve to 1910 K and 8.84 dB, respectively.
Low scattering structures for reflector antennas

In numerous space applications, antenna performance is degraded by the scattering of electromagnetic waves on the antenna structure or on neighboring objects. The present paper describes the design and measurements of two types of low scattering antenna structures for space applications. The first type of structure is a low-scattering feed supporting structure or strut typically used for center-fed antennas. The second type of structure is a low-scattering post designed as a replacement for conventional dielectric posts used to mechanically connect the front and back shells of Dual-Gridded Reflector antennas. Measurements and simulations of center-fed antennas with conventional struts and with the low-scattering struts as well as measurements and simulations of the DGR with conventional posts and low-scattering posts show that the performance of space antennas can be improved, in some cases significantly, by using these novel low-scattering structures.
On photo-realistic 3D reconstruction of large-scale and arbitrary-shaped environments

This paper presents a system architecture for reconstructing photorealistic and accurate 3D models of indoor environments. The system specifically targets large-scale and arbitrary-shaped environments and enables processing of data obtained with an arbitrary-chosen capturing path. The system extends the baseline Kinect Fusion algorithm with a buffering algorithm to remove scene-size capturing limitations. Beside this, the paper presents the complete chain of advanced algorithms for point cloud segmentation/decimation, camera pose correction and texture mapping with post-processing filters. The presented architecture features memory- and processor-efficient processing, such that it can be executed on a conventional PC with a mainstream GPU card at the consumer premises.
A 1/1.8" 3M pixel FT-CCD with on-chip horizontal sub-sampling for DSC applications

A 1/1.8" 3M-pixel frame-transfer CCD (FT-CCD) with on-chip horizontal sub-sampling allows an additional preview mode where the image extraction rate is doubled (up to 60 images/s) while keeping the 25 MHz classic readout frequency. High-sensitivity video clips, fast autofocus, and auto-exposure is achieved on digital still cameras.
Real-time free-viewpoint DIBR on GPUs for 3DTV systems

Multi-view 3D may succeed stereo 3DTV in multimedia and TV applications. To this end, the MPEG committee has installed a special task force to establish a standard for multi-view 3D coding. One focal point of our research work is on an efficient implementation of the rendering part of such a multi-view 3D system, because it is a computationally expensive task and it determines the final reconstructing quality. Our free-viewpoint DIBR algorithm is implemented with an off-the-shelf GPU that can be integrated in advanced 3DTV systems. We present the principal steps of a representative free-viewpoint DIBR and show the key differences between the reference software and our GPU implementation. One of those differences is the joint execution of signal processing blocks to share memory usage. Using a combination of the highly parallel programming architecture CUDA and a graphics API, we have achieved a real-time performance operating on 1080p HD multi-view video with a rendering quality that is comparable to the software implementation.
Chip-set for video display of multimedia information

This paper presents a chip-set for digital video processing in a consumer television receiver. A key aspect of the chip-set is a high flexibility and programmability of multi-window features with multiple teletext pages, Internet pages and up to three live video windows. The chip-set consists of a microcontroller featuring pixel-based graphics, and a video processor containing a number of flexible co-processors for horizontal and vertical scaling, sharpness enhancement, adaptive temporal noise reduction, blending of graphics, mixing of multiple video streams and 100 Hz up-conversion.
Wireless Sensor Network interconnection protocol

Wireless Sensor Networks (WSNs) are at high speed gaining in popularity. Because of this increased adoption, the need for integration with existing technologies becomes more prominent. In practice, a WSN is often deployed in environments where both wired and wireless data networks are also present. Consider for instance a WSN which acts as a climate monitoring or fire detection system in a large office building. As WSNs are typically networks with high constraints regarding resource efficiency, it would be beneficial if they could use the available data networks as additional transport medium for their internal data. In this paper we describe an interconnection protocol and associated sensor gateway design which enables the transparent use of both wired and wireless data networks by WSNs. Through this setup, the WSN will detect the non-sensor devices as virtual sensor nodes and consider them when determining the optimal routing paths.
CT based prostate cancer patient-specific transperineal ultrasound probe setups for image guided radiotherapy

Radiotherapy aims at irradiating tumor tissue, while sparing normal tissue as much as possible and it is a suitable treatment option for prostate cancer. A crucial aspect of the radiotherapy workflow is patient positioning. It has been shown that frequent imaging during the course of the treatment (image guided radiotherapy) can improve this positioning accuracy. Despite the many advantages of ultrasound imaging (high soft tissue contrast, 4D imaging, etc.) its use in image guided radiotherapy workflows is not widespread. This can be primarily attributed to the need for a trained operator during image acquisition. In this study, patient-specific transperineal ultrasound probe setups were automatically calculated based on CT scans of prostate cancer patients. These setups seem to meet clinical requirements and their use can potentially minimize operator dependence and improve usability for relatively untrained operators. In the end, this could allow patients to fully benefit from the unique characteristics of this imaging modality.
WBAN Implementation on Magnetic Induction Radio IC for Medical Remote Monitoring

The medical service environment is changing. There is a need for automatization of collecting medical data remotely from the patient. Telecare is the continuous remote monitoring of the health of the patient. The IM3 (interactive mobile medical monitoring) project focuses on developing and implementing such end-to-end service. We implemented the WBAN (wireless body area network) protocol on the magnetic induction radio IC (integrated circuit), which is designed by NXP Semiconductors. We show in this paper that we have a working setup, where nodes form autonomously the network and send ECG data to the sink.