nils-herrmann/clean_scirepeval huggingface dataset:
Instability of MaxWeight Scheduling Algorithms

MaxWeight scheduling algorithms provide an effective mechanism for achieving queue stability and guaranteeing maximum throughput in a wide variety of scenarios. The maximum-stability guarantees however rely on the fundamental premise that the system consists of a fixed set of sessions with stationary ergodic traffic processes. In the present paper we examine a scenario where the population of active sessions varies over time, as sessions eventually end while new sessions occasionally start. We identify a simple necessary and sufficient condition for stability, and show that MaxWeight policies may fail to provide maximum stability. The intuitive explanation is that these policies tend to give preferential treatment to flows with large backlogs, so that the rate variations of flows with smaller backlogs are not fully exploited. In the usual framework with a fixed collection of flows, the latter phenomenon cannot persist since the flows with smaller backlogs will build larger queues and gradually start receiving more service. With a dynamic population of flows, however, MaxWeight policies may constantly get diverted to arriving flows, while neglecting the rate variations of a persistently growing number of flows in progress with relatively small remaining backlogs. We also perform extensive simulation experiments to corroborate the analytical findings.
Electromagnetic-Bandgap Waveguide for the Millimeter Range

This paper presents the design, manufacturing, and characterization of a waveguide based on electromagnetic-bandgap (EBG) technology working in W-band. A modified silicon EBG woodpile structure was used in order to improve the matching performance of the EBG waveguide to a standard rectangular waveguide. The transition between the silicon EBG woodpile waveguide and the conventional WR10 waveguide was optimized and a 13.5% bandwidth around 90 GHz was achieved. The measured insertion losses remained better than 3 dB in the overall working bandwidth.
Triple-C: Resource-usage prediction for semi-automatic parallelization of groups of dynamic image-processing tasks

With the emergence of dynamic video processing, such as in image analysis, runtime estimation of resource usage would be highly attractive for automatic parallelization and QoS control with shared resources. A possible solution is to characterize the application execution using model descriptions of the resource usage. In this paper, we introduce Triple-C, a prediction model for Computation, Cache-memory and Communication-bandwidth usage with scenario-based Markov chains. As a typical application, we explore a medical imaging function to enhance objects of interest in X-ray angiography sequences. Experimental results show that our method can be successfully applied to describe the resource usage for dynamic image-processing tasks, even if the flow graph dynamically switches between groups of tasks. An average prediction accuracy of 97% is reached with sporadic excursions of the prediction error up to 20–30%. As a case study, we exploit the prediction results for semi-automatic parallelization. Results show that with Triple-C prediction, dynamic processing tasks can be executed in real-time with a constant low latency.
On the charging and thermal characterization of a micro/nano structured thermal ground plane

As power densities in electronic devices have increased dramatically over the last decade, advanced thermal management solutions are required. A significant part of the thermal resistance budget is commonly taken up by the heat spreader, which serves to reduce the input heat flux and connect to an increased area for heat removal. Thermal ground planes are devices that address this issue by utilizing two-phase heat transfer achieving higher effective thermal conductivities than conventional solid heat spreaders. This study describes the need for and design of a charging station to accurately dispense the working fluid and a thermal characterization experiment to characterize performance. The design study includes detailed analysis of accuracy and validation of the setup.
On the Need for Evolvability Assessment in Value Management

Contemporary organizations need to dynamically adapt to their rapidly changing environment. This imposes challenges to the entire organization, including its supporting information systems (IS). However, current value management practices pay little attention to evolvability issues within the evaluation and deployment of information technology dependent strategic initiatives (ITDSIs). In this paper, we explore how the evolvability of an information technology (IT) application can be assessed and which practices might be affected if an organization is willing to address this issue. For this purpose, we propose a set of five specific management guidelines. These should lead to ITDSIs yielding more evolvable information systems to an organization, and hence enable the organization to more easily adapt to its environment, providing a competitive advantage.
Resource efficient streaming bearer concept for GERAN

We present a complete concept for providing a resource efficient bearer service for streaming applications in the GSM/EDGE Radio Access Network, GERAN. The concept comprises rules for admission control, service quality monitoring functions and appropriate means to ensure that the service quality stays within the envisaged bounds. Results indicate that the achievable capacity is close to what could be expected from streaming over a best effort bearer, while at the same time QoS guarantees can be fulfilled, ensuring high end-user quality.
A low-cost fabrication technique for symmetrical and asymmetrical layer-by-layer photonic crystals at submillimeter-wave frequencies

This paper presents a rapid, versatile, and practical technique for the manufacture of layer-by-layer photonic crystals in the millimeter- and submillimeter-wave regions. Mechanical machining is used to derive a rugged layer-by-layer structure from high-resistivity silicon wafers. Unlike traditional anisotropic etching techniques, this method does not rely on any particular crystal orientation of the substrate and allows greater flexibility in the photonic crystal design. Automatic alignment of alternating layers is achieved via careful placement of the separation cuts. Using this ability, two configurations of photonic crystals are realized and their RF characteristics are measured and presented. Firstly, a symmetrical photonic crystal is studied as an initial demonstration of the technique. This is followed by an asymmetrical example, where a different frequency response is observed for the two orthogonal polarizations of the incident radiation. Two measurement techniques are used to characterize the photonic crystals and the merits of each are discussed. Theoretical predictions are seen to agree well with the measured behavior.
An advanced sampling rate conversion technique for video and graphics signals

We propose an advanced sampling rate conversion technique for TV applications, which enables high-quality conversions for both video and graphics signals. The converter has to satisfy two important constraints in order to obtain high-quality conversion. Firstly, the filter characteristics need to be adjusted to the statistics of the input signal (graphics vs. natural video scenes). Secondly, the system should operate well for both compression and expansion. It is known that high-quality compression is more difficult to realize, because the output signal may suffer from aliasing due to the required filtering of the baseband spectrum. The inequality between compression and expansion was solved by transposing the converter starting with the architecture for expansion based on a polyphase filter. This proposal is attractive because the transposed structure inherently prefilters the input signal according to the compression factor. Promising simulation results proved that high-quality conversion was indeed obtained in both cases.
Channel length extraction for DMOS transistors using capacitance-voltage measurements

This paper presents a new measurement method for extraction of submicrometer channel lengths in double diffused MOS (DMOS) transistors. The method is based on capacitance-voltage (CV) measurements of the gate to p-base and the gate to drain capacitance. A channel length of 0.3 /spl mu/m has been measured on DMOS transistors. Numerical device simulations and small-signal capacitance simulations support the result and the measurement principle along with scanning capacitance microscopy (SCM) measurements.
Full-wave characterization of planar EBG structures by the MoM/BI-RME method

The paper presents a novel method for the the calculation of the dispersion diagram and the phase of the reflection coefficient of planar electromagnetic band-gap (EBG) structures. The MoM/BI-RME (boundary integral-resonant mode expansion) method is adopted in conjunction with a new technique for the efficient calculation of the dispersion diagram. This technique is based on the tracking of the eigenvalue in the complex plane, and proves more reliable than the search of the determinant zeros. The analysis of the classical uniplanar compact EBG structure is presented.
Managing mixed services with controlled QoS in GERAN-the GSM/EDGE radio access network

Managing multiple services with controlled quality of service (QoS) is crucial to 3rd generation cellular systems. This paper describes and evaluates a simple radio resource management scheme; service-based power setting, employed to accomplish this goal for the GSM/EDGF radio access network (GERAN). Simulation results indicate that with proper power offsets between bearer services previously established high capacities for single services may be maintained also for a mix of different services with controlled QoS.
Broadcast Court-Net Sports Video Analysis Using Fast 3-D Camera Modeling

This paper addresses the automatic analysis of court-net sports video content. We extract information about the players, the playing-field in a bottom-up way until we reach scene-level semantic concepts. Each part of our framework is general, so that the system is applicable to several kinds of sports. A central point in our framework is a camera calibration module that relates the a-priori information of the geometric layout in the form of a court model to the input image. Exploiting this information, several novel algorithms are proposed, including playing-frame detection, players segmentation and tracking. To address the player-occlusion problem, we model the contour map of the player silhouettes using a nonlinear regression algorithm, which enables to locate the players during the occlusions caused by players in the same team. Additionally, a Bayesian-based classifier helps to recognize predefined key events, where the input is a number of real-world visual features. We illustrate the performance and efficiency of the proposed system by evaluating it for a variety of sports videos containing badminton, tennis and volleyball, and we show that our algorithm can operate with more than 91% feature detection accuracy and 90% event detection.
5.5-V I/O in a 2.5-V 0.25-μm CMOS technology

A robust high-voltage-tolerant I/O that does not need process options is presented, demonstrated on 5.5-V-tolerant I/O in a 2.5-V 0.25-/spl mu/m CMOS technology. Circuit techniques limit oxide stress and hot-carrier degradation. Measurements on realized circuits, under accelerated stress conditions, indicate an extrapolated lifetime of hundreds of years for 5.5-V pad voltage swing, 2.2-V supply voltage. The shown concepts can easily be scaled toward newer processes or other interfacing voltages.
Pulsed Optical Pumping as a Tool for the Determination of Population Mechanisms of Excited States in a Low-Pressure Mercury Discharge

Experiments are described in which a low-pressure mercury discharge is irradiated with a dye-laser pulse tuned resonant to one of the 6 3P-7 3S1 mercury transitions. The effects of this optical pumping process are monitored via fluorescence on many mercury transitions. The sign and time behavior of each fluorescence signal are different, and are determined by one or more of the following processes: a) radiative decay of the 7 3S1 level; b) a change in electron-impact excitation rate from the ground state induced by the optogal-vanic effect (OGE). This OGE results from the population redistribution in the 6 3P levels after radiative decay of the 7 3S1 level; c) a change in electron-impact excitation rate from the 6 3P levels; and d) a change in 6 3P-6 3P collisional excitation rate. It is demonstrated that the signal and time behavior of the fluorescence signals induced by the pulsed optical pumping process can be used to determine the population mechanism(s) of excited states qualitatively.
Schottky diode technology at Rutherford Appleton Laboratory

Most parts of the electromagnetic spectrum are well understood and exploited, but the terahertz region between the microwave and infrared is still relatively under developed. Potential receiver applications are wide-ranging and cross-disciplinary, spanning the physical, biological, and medical sciences. In this spectral region, Schottky diode technology is uniquely important. InP MMIC amplifiers are generally limited to frequencies less than ∼200 GHz, above which their noise performance rapidly deteriorates. Superconducting circuits, which require cooling, may not always be practical. Either as varistor diodes (heterodyne mixing), or varactor diodes (sub-millimetre power generation), Schottky technology underpins terahertz receiver development. Two important developments have occurred in recent years. First, the underpinning technology base has demonstrably matured. Planar Schottky diode technology has been shown to be practical at frequencies as high as 2,500 GHz, and frequency multipliers have been shown to be capable of generating 100s of mW at frequencies around W-band. Secondly, circuit designs can now be optimised theoretically with CAD electromagnetic structure simulators and non-linear analysis programs. New high-speed computer controlled mills, improved lithographic capabilities and micro-machining techniques also offer exciting new options for cavity and circuit manufacture. This paper describes the Schottky diode technology currently being developed at the Rutherford Appleton Laboratory. Discrete diode components are described as well as integrated diode/filter circuits. Frequency multiplier diode structures are reported which include novel substrate transfer techniques to reduce the effects of dielectric loading and self-heating.
Adaptive thresholds for AMR codec mode selection

The speech codecs from the adaptive multi-rate (AMR) codec family enable provisioning of excellent speech quality, at the same time providing a way forward towards state-of-the-art, spectrally efficient, high capacity cellular networks. One straightforward way to characterize the benefit of AMR speech codecs is that the robustness to interference and noise in radio networks is increased and that this advantage over other, nonadaptive, speech codecs can be capitalized on in several different ways, e.g., by enhancing speech quality or improving system capacity. In this paper, improved mode adaptation, where codec mode switching thresholds are adaptive to radio conditions, is discussed. Example simulations show that an adaptive thresholds algorithm applied to GSM can significantly improve objective speech quality. Corresponding improvements were also found in informal listening tests.
Primary and secondary statistics of rain attenuation and rain rate measured on a satellite-to-Earth path in Indonesia

Results of a three-year propagation measurement campaign at Ku-band (11/14 GHz) in Surabaya, Indonesia are presented. These include primary (cumulative distributions of measured total attenuation, derived attenuation, and rainfall) and secondary (diurnal variations) statistics. Furthermore, a comparison is made between the results and predictions based on the ITU-R (formerly CCIR) models.
Oblique incidence measurements of circular polarization selective surfaces

The performance of circular polarization selective surfaces (CPSS) under oblique incidence is examined experimentally. A fabricated CPSS prototype working around 10GHz has been characterized under oblique incidence ranging angles between ±30°. It was found that increasing the angle of incidence, the frequency at which minimal axial ratio (AR) is achieved deviates from the resonant frequency of the CPSS, resulting in higher AR within a given bandwidth. Design guidelines will be given in order to minimize this limitation.
Equivalent network for a slot-coupled elliptical integrated lens antenna

A method is presented for the design and the analysis of a dielectric elliptical lens antenna slot fed by a microstrip. The elliptical shape of the lens gives a focusing property provided that the eccentricity is properly related to the dielectric constant. In particular, under this condition, all the rays outgoing from the source are refracted in the boresight direction, thus providing the focusing phenomenon. On the other hand the lens interface gives rise to reflections. Indeed, the geometrical properties of the lens itself are such that all the doubly reflected rays launched by a focal source return in phase at the original focus. In view of this property, the availability of tools for the accurate prediction of the input impedance of the antenna including multiple reflections effects is particularly important owing to the limited tuning possibilities intrinsic with integrated technology. Regarding the feed arrangement, we propose the same as that typically used in patch antennas, namely a slot which is excited by a microstrip printed on a back substrate. This structure presents several advantages, primarily due to the physical separation between the radiating elements and the feeding network. Furthermore, with respect to the alternative slot feed arrangement involving coplanar waveguides (CPW) the present solution provides radiation pattern regularity and polarization purity, which are important features in quasi-optical receiver front-ends.
Reflection Properties of a planar structure combining AMC and PEC cells

In this paper a new structure which combines artificial magnetic conductor (AMC) and perfect electric conductor (PEC) cells to reduce the radar cross section (RCS) is presented. In the proposed structure AMC cells are filled with the so-called "mushroom" structure. AMC and metallic cells are combinated to create a 180deg of phase difference between the reflected waves in each cell, creating a destructive interference. Under normal incidence the reflected power in the scattered specular direction is minimized and the power is redirected in the phi = 45deg and 135deg planes at theta = 45deg direction. As a first step a theoretical model is presented based on array theory and finally the simulated results using the commercial software Ansoft HFSS are shown.
Compositional Performance Analysis of Component-Based Systems on Heterogeneous Multiprocessor Platforms

This paper presents a compositional performance analysis technique, enabling predictable deployment of software components on heterogeneous multiprocessor architectures. This analysis technique introduces (a) composable software and hardware component models representing abstract specification of the component behaviour and corresponding resources, (b) operational semantics enabling composition of the models into an executable system model, and (c) simulation-based analysis of the obtained executable model resulting in predicted performance attributes. Example attributes are response time, throughput, utilization of processors, memory and communication lines. Special attention is paid to modeling of both passive and active components exploiting synchronous method invocation and asynchronous message passing interaction. We made an experimental validation of the above framework for two case studies: an MPEG-4 decoder and a car navigation system. It was found that the prediction error on task latencies and processor usage was within 10%
Robust clustering-based video-summarization with integration of domain-knowledge

Clustering techniques have been widely used in automatic video-summarization applications to group shots with comparable content. We enhance the popular k-means clustering algorithm to integrate user-supplied domain-knowledge into the cluster generation step. This provides a convenient way to exclude scenes from the summary which are a-priori known to be irrelevant. Furthermore, we added an additional, time-constrained clustering step preceding the scene clustering step to exclude short ranges with transitional content. This makes the algorithm robust to fading and wipe-effects in the input without requiring explicit cut detection.
Higher Order Modulation and Turbo Coding for GSM/EDGE Continued Evolution

GSM/EDGE is the world's largest and most widespread cellular technology. EDGE offers an attractive solution for 3rd generation cellular services in existing GSM networks. The introduction of new services into an existing network typically leads to increased capacity demands, since more users of different service types need to coexist in limited spectrum, while the existing speech service is required to function at least as well as before. Higher Order Modulation in combination with Turbo Coding is proposed to substantially enhance spectrum efficiency and average user bit rates in GSM/EDGE through improved interference robustness and increased peak bit rates. Simulation results indicate link level gains of 2.5-5.5 dB. When additionally applying incremental redundancy, similar relative improvements are shown. Bit rates can be increased by more than 30%, at C/I levels above 30dB. System performance gains are indicated by average user bit rate enhancements of up to 30-40%, along with substantial gains in spectrum efficiency, up to 40%. It is also shown that system gains are rather insensitive to frequency reuse and whether frequency hopping is applied or not (in sparse reuse scenarios).
Experiments with the Tangora 20,000 word speech recognizer

The Speech Recognition Group at IBM Research in Yorktown Heights has developed a real-time, isolated-utterance speech recognizer for natural language based on the IBM Personal Computer AT and IBM Signal Processors. The system has recently been enhanced by expanding the vocabulary from 5,000 words to 20,000 words and by the addition of a speech workstation to support usability studies on document creation by voice. The system supports spelling and interactive personalization to augment the vocabularies. This paper describes the implementation, user interface, and comparative performance of the recognizer.
A model based simulation toolkit for evaluating renal replacement policies

Renal failure concerns progressive loss of kidney function. Renal Replacement Therapy (RRT) is a costly, long-running process that includes several decision points in different stages. Small changes in the protocol can impact significantly the expenditures and healthcare outcomes. Unfortunately, policy makers have very little support for benchmarking improvement alternatives. The existing models are designed to fit certain applications with preset parameters and design choices which do not match with the requirements of a policy analysis. A generic approach is required to analyze the effects of different design options adjustable to finer scales. To remedy this, this paper describes a novel toolkit for evaluating renal replacement policies, containing a parametrized colored Petri-Net which can be configured for the specifics of local settings. The model is made available for open access to overcome the non-replicability issue of existing models.