Element Count Research Articles

Analysis of a Wavelength-Scaled Array (WSA) Architecture

Wavelength-scaled array architectures use scaled elements to achieve ultrawideband performance with significantly fewer overall radiators than traditional ultrawideband arrays based on a single element type. Compared to a conventional ultrawideband array with 8:1 bandwidth, a wavelength-scaled array that uses elements of three different sizes creates an aperture with fewer than 16% of the original element count, i.e., 6.4-times fewer elements, and by extension a comparable reduction in electronics required to feed the array. In this paper, a study of an asymmetric wavelength-scaled array architecture is presented for finite arrays of offset-centered dual-polarized flared-notch radiators. The unique element transitions within the finite array structure are modeled via a non-matching grid Domain Decomposition-Finite Element Method that allows for rigorous impedance and radiation pattern prediction of full-sized wavelength-scaled arrays. This design study shows that the wavelength-scaled array has comparable performance to traditional ultrawideband arrays in terms of VSWR, radiation patterns, array mismatch efficiency, and cross-polarization levels.

Nature-Inspired Design Techniques for Ultra-Wideband Aperiodic Antenna Arrays

Over the past few decades, much research has been invested in the exploration of wideband and ultra-wideband (UWB) antenna arrays. The goals of such array designs are to determine the best element arrangements, which yield radiation patterns possessing the highest degrees of side lobe suppression, and no grating lobes over the largest possible operating bandwidths. It has been recently shown that nature-inspired array-design methodologies can provide solutions that exhibit these ultra-wideband characteristics. This article provides an overview of two such designs: linear polyfractal arrays, and planar arrays of aperiodic tilings. Robust nature-inspired genetic-algorithm optimization techniques were utilized in the design of both types of arrays in order to obtain the best-possible UWB performance. This article also discusses the fabrication and experimental validation of two 32-element linear polyfractal array-design prototypes, which exhibited close agreement to the radiation performance predicted by simulation. These experimentally validated arrays possessed wide bandwidths with suppressed grating lobes and relatively low sidelobes for their size (-16.3 dB at f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> and -5.39 dB at f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> )Additional simulations discussed in this paper showed that the benefits of these methodologies are amplified when applied to larger sized array designs (Le., arrays with larger element counts). One example exhibited a peak sidelobe level less than -19.34 dB over a 40:1 bandwidth.

The frequent items problem, under polynomial decay, in the streaming model

We consider the problem of estimating the frequency count of data stream elements under polynomial decay functions. In these settings every element in the stream is assigned with a time-decreasing weight, using a non-increasing polynomial function. Decay functions are used in applications where older data is less significant, less interesting or even less reliable than recent data. Consider a data stream of N elements drawn from a universe U . We propose three poly-logarithmic algorithms for the problem. The first one, deterministic, uses O ( 1 ϵ 2 log N ( log log N + log U ) ) bits, where ϵ ∈ ( 0 , 1 ) is the approximation parameter. The second one, probabilistic, uses O ( 1 ϵ 2 log N δ log 1 ϵ ) bits or O ( 1 ϵ 2 log N δ log N ) bits, depending on the decay function parameter, where δ ∈ ( 0 , 1 ) is the probability of failure. The third one, deterministic in the stochastic model, uses O ( 1 ϵ log U ) bits or O ( 1 ϵ 2 log N ) bits, also depending on the decay parameter as will be described in this paper. This variant of the problem is important and has many applications. To our knowledge, it has never been studied before.

New RTD‐Based General Threshold Gate Topologies and Application to Three‐Input XOR Logic Gates

This paper presents two new general threshold gate (GTG) structures which are based on the monostable‐bistable element (MOBILE) as their main part. These new GTGs eliminate an RTD from the structure compared to old structures and lead to less elements count and better performance in terms of power consumption, maximum frequency, and power‐delay product (PDP). In the paper also two new single gate three‐input XOR logic gates based on the old GTGs and two ones based on the new GTGs are presented and simulated in HSPICE simulator.

Preliminary Investigations of a Low-Cost Ultrawideband Array Concept

A design concept is presented that achieves ultra wideband (UWB) array performance with significantly fewer elements than the traditional approach of using a single wideband antenna element type to fully populate the array. Starting from a conventional 8:1 bandwidth array design of a given aperture size, an array of equivalent aperture and bandwidth is created using scaled elements of three different sizes. This wavelength-scaled equivalent array has fewer than 18% of the original element count, i.e., roughly 6-times fewer elements, a similar reduction in weight, and most importantly, a significant reduction in electronics required to feed the array. If proven viable, array architectures of this type could make UWB arrays significantly more cost effective. In this preliminary numerical study, rigorous full-wave simulation tools are used to test the performance of small but informative wavelength-scaled array configurations of flared-notch radiators for the single-polarization case.

The shell game: analytic problems in archaeological mollusc quantification

MNI calculations for archaeological molluscs that rely on counts of non-repetitive elements (NREs) are popular for their analytic speed and efficiency. Yet the reliability of this approach as compared to ‘traditionally’ calculated MNI has not been explored. Here, I examine these approaches using data from the Caribbean coastal midden site of Grand Bay, Carriacou. Results suggest that an NRE-based approach to MNI calculation can be unreliable under certain circumstances. In addition, dependence on the NRE-based method may hinder the integration of invertebrate with vertebrate data, obscuring a holistic understanding of prehistoric diet and resource exploitation. These findings are discussed in relation to practical constraints and fulfillment of zooarchaeological goals.

A Semi-Empirical Pressure Drop Model: Part II—Multi-Element Pleated Filter Banks

Multi-element pleated filter banks (MEPFBs) combine numerous removable pleated filters into a single housing to increase the available media area, while operating at a reduced pressure drop. A predictive resistance model was developed through the use of fundamental fluid dynamic equations and empirical data to gain a working knowledge of the design parameters and their contribution to the initial resistance of these filtration systems. The model was shown to accurately replicate 750 experimental pressure drop versus face velocity data points spanning thirty custom-made MEPFBs of various filter element counts, element widths, element depths, pleat counts, and media types. MEPFBs were evaluated using the pressure drop model to determine the limiting resistance terms for a given design as well as methods to optimize energy consumption and increase the available media area of a filtration unit.

First lacustrine varve chronologies from Mexico: impact of droughts, ENSO and human activity since AD 1840 as recorded in maar sediments from Valle de Santiago

We present varve chronologies for sediments from two maar lakes in the Valle de Santiago region (Central Mexico): Hoya La Alberca (AD 1852–1973) and Hoya Rincon de Parangueo (AD 1839–1943). These are the first varve chronologies for Mexican lakes. The varved sections were anchored with tephras from Colima (1913) and Paricutin (1943/1944) and 210Pb ages. We compare the sequences using the thickness of seasonal laminae and element counts (Al, Si, S, Cl, K, Ti, Mn, Fe, and Sr) determined by micro X-ray fluorescence spectrometry. The formation of the varve sublaminae is attributed to the strongly seasonal climate regime. Limited rainfall and high evaporation rates in winter and spring induce precipitation of carbonates (high Ca, Sr) enriched in 13C and 18O, whereas rainfall in summer increases organic and clastic input (plagioclase, quartz) with high counts of lithogenic elements (K, Al, Ti, and Si). Eolian input of Ti occurs also in the dry season. Moving correlations (5-yr windows) of the Ca and Ti counts show similar development in both sequences until the 1930s. Positive correlations indicate mixing of allochthonous Ti and autochthonous Ca, while negative correlations indicate their separation in sublaminae. Negative excursions in the correlations correspond with historic and reconstructed droughts, El Nino events, and positive SST anomalies. Based on our data, droughts (3–7 year duration) were severe and centred around the following years: the early 1850s, 1865, 1880, 1895, 1905, 1915 and the late 1920s with continuation into the 1930s. The latter dry period brought both lake systems into a critical state making them susceptible to further drying. Groundwater overexploitation due to the expansion of irrigation agriculture in the region after 1940 induced the transition from calcite to aragonite precipitation in Alberca and halite infiltration in Rincon. The proxy data indicate a faster response to increased evaporation for Rincon, the lake with the larger maar dimensions, solar radiation receipt and higher conductivity, whereas the smaller, steeper Alberca maar responded rapidly to increased precipitation.

A dual-layer transducer array for 3-D rectilinear imaging.

Very large element counts (16,000-65,000) are required for 2-D arrays for 3-D rectilinear imaging. The difficulties in fabricating and interconnecting 2-D arrays with a large number of elements (>5,000) have limited the development of suitable transducers for 3-D rectilinear imaging. In this paper, we propose an alternative solution to this problem by using a dual-layer transducer array design. This design consists of 2 perpendicular 1-D arrays for clinical 3-D imaging of targets near the transducer. These targets include the breast, carotid artery, and musculoskeletal system. This transducer design reduces the fabrication complexity and the channel count, making 3-D rectilinear imaging more realizable. With this design, an effective N x N 2-D array can be developed using only N transmitters and N receivers. This benefit becomes very significant when N becomes greater than 128, for example. To demonstrate feasibility, we constructed a 4 x 4 cm prototype dual-layer array. The transmit array uses diced PZT-5H elements, and the receive array is a single sheet of undiced P[VDF-TrFE] copolymer. The receive elements are defined by the copper traces on the flexible interconnect circuit. The measured -6 dB fractional bandwidth was 80% with a center frequency of 4.8 MHz. At 5 MHz, the nearest neighbor crosstalk of the PZT array and PVDF array was -30.4 +/- 3.1 dB and -28.8 +/- 3.7 dB, respectively. This dual-layer transducer was interfaced with an Ultrasonix Sonix RP system, and a synthetic aperture 3-D data set was acquired. We then performed offline 3-D beamforming to obtain volumes of nylon wire targets. The theoretical lateral beamwidth was 0.52 mm compared with measured beamwidths of 0.65 mm and 0.67 mm in azimuth and elevation, respectively. Then, 3-D images of an 8 mm diameter anechoic cyst phantom were also acquired.

Hexahedral mesh generation constraints

For finite element analyses within highly elastic and plastic structural domains, hexahedral meshes have historically offered some benefits over tetrahedral finite element meshes in terms of reduced error, smaller element counts, and improved reliability. However, hexahedral finite element mesh generation continues to be difficult to perform and automate, with hexahedral mesh generation taking several orders of magnitude longer than current tetrahedral mesh generators to complete. Thus, developing a better understanding of the underlying constraints that make hexahedral meshing difficult could result in dramatic reductions in the amount of time necessary to prepare a hexahedral finite element model for analysis. In this paper, we present a survey of constraints associated with hexahedral meshes (i.e., the conditions that must be satisfied to produce a hexahedral mesh). In presenting our formulation of these constraints, we will utilize the dual of a hexahedral mesh. We also discuss how incorporation of these constraints into existing hexahedral mesh generation algorithms could be utilized to extend the class of geometries to which these algorithms apply. We also describe a list of open problems in hexahedral mesh generation and give some context for future efforts in addressing these problems.

Configurable Data Memory for Multimedia Processing

In modern multimedia applications, memory bottleneck can be alleviated with special stride data accesses. Data elements in stride access can be retrieved in parallel with parallel memories, in which the idea is to increase memory bandwidth with several memory modules working in parallel and feed the processor with only necessary data. Arbitrary stride access capability with interleaved memories is described in previous research where the skewing scheme is changed at run time according to the currently used stride. This paper presents the improved schemes which are adapted to parallel memories. The proposed novel parallel memory implementation allows conflict free accesses with all the constant strides which has not been possible in prior application specific parallel memories. Moreover, the possible access locations are unrestricted and the accessed data element count equals to the number of memory modules. Timing and area estimates are given for Altera Stratix FPGA and 0.18 micrometer CMOS process with memory module count from 2 to 32. The FPGA results show 129 MHz clock frequency for a system with 16 memory modules when read and write latencies are 3 and 2 clock cycles, respectively. The complexity of the proposed system is shown to be a trade-off between application specific and highly configurable parallel memory system.

Methodological strategy for the analysis of human dental enamel by LA-ICP-MS

The application of LA-ICP-MS to human dental enamel usually follows a methodological procedure that starts with the vertical sawing of the tooth in order to obtain a flat surface. However, the inner enamel can be accessed in archaeological teeth that are fractured for natural, taphonomic reasons, which reduces further damage to archaeological specimens by cutting them. This paper analyzes the differences in the counts of trace elements by laser ablation–inductively coupled plasma–mass spectrometry between a cut and broken surface from the same teeth. Results show that the two surfaces do not produce statistically different readings, which extends the possibility to apply this methodological procedure to archaeological remains that cannot be sectioned, and therefore reducing the amount of damage effected to important specimens.

Market Consistent Embedded Values as 'Fair Value' Measurements for Life Insurance Accounting: A Step Too Far With Finance Theory?

Embedded value has been widely adopted by European and Canadian life insurance companies for supplementary performance reporting and increasingly by US insurers for management purposes. It has important implications for the international debate over the appropriate use of fair values in financial reporting. But EV has still not been accepted by standard setters (e.g. IASB) for inclusion in the main financial statements. The concept of Market Consistent Embedded Value has been developed primarily by actuaries utilizing modern financial economics. This paper analyzes how both top-down and bottom-up methodologies for estimating MCEV may lead to unrealistic allowance for risk and explores the dangers of double counting of elements in the MCEV 'economic balance sheet', of a misunderstanding of the synergistic nature of overall firm value, and of a naive belief in market efficiency. It outlines potential empirical research with wider implications for 'fair value' accounting and reporting.

Factors influencing the teamwork intensity in basketball.

The purpose of this paper is to analyze the offensive team activity and to determine factors influencing the teamwork intensity in basketball. We were able to determine the teamwork structure by using a system of analysis of the offensive process. The analysis of the team activity as an integrated whole becomes very important.For this research we observed the Tallinn University basketball team, which plays in Division One of the Estonian league. The data was gathered from 600 ball possessions in 8 recorded games of the regular season. The data we collected (the count of elements in the offensive zone during one team s ball possession: dribbles, passes, screens on the ball, screen off s the ball, shots; the time in possession during the transition, ball possession in the offensive zone and total time; the type of offence: fast break, early offence or set offence; the beginning: after steal, defensive rebound or inbound) was analyzed by the means of data mining. Data mining summarises the data and presents the main patterns. It meets this target by listing the relations between all the values in each field and the dependent variable. The method employs a unique algorithm that segments numeric fields in an optimal way, and displays the relation between each interval and the value under analysis. This analysis of the basic rules and trends results in the summary of the data.The analyzing system of the competitive activity of the game, enables us to find out interesting offensive teamwork models from the data. The results showed that the teamwork intensity index was equal to 0,82 on average (SD = 0.26) with a frequancy of 43%. Trend report show, that the main impact factors influencing the teamwork intensity in offensive zone are time in possession in offensive zone (prediction power 67), the total time of ball possession (prediction power 59) and screen off s the ball (prediction power 39).On the basis of the research, the coach can evaluate the activity of the team and correct the strategy for future games. The analyzing system worked out through that helps coaches to develop performance and promote learning.

Critical evaluation of the biological role of IgM in cerebrospinal fluid in inflammatory and other diseases of the nervous system

In a group of 10,156 patients with neurological diseases, the IgM level was assessed (using laser nephelometry) both in cerebrospinal fluid (CSF) and serum; concentration of other 17 protein fractions was also simultaneously determined: albumin, immunoglobulins, acute phase reactants, complement components, apolipoproteins, proteinase inhibitors and alpha1-microglobulin. Total protein, element counts and glucose level were also evaluated. In patients with normal CSF findings, only limited statistically significant correlations were demonstrated between IgM and other CSF protein fractions while, in the group of patients with pathological CSF findings, significant correlations were found between CSF(IgM) and other immunoglobulins, complement fractions and the rate of intrathecal synthesis of immunoglobulins. Correlations were also found between CSF(IgM) and CSF antithrombin-III and alpha1-microglobulin. Correlations between CSF(IgM) and CSF apolipoproteins support the theory of CNS tissue destruction whenever the concentration of CSF apolipoproteins is elevated. Our data substantially contribute to establishing the diagnosis in patients with neurological diseases; simultaneous measurement of a high number of CSF proteins is becoming inevitable for a reasonable assessment of the CSF Protein Status.

Performance analysis of conformal conical arrays for airborne vehicles

Conformal array apertures have great potential for providing high performance, low weight systems with little or no impact to the aerodynamic design of the air vehicle. A performance analysis of conformal conical arrays for a national airborne radar application is presented. The conical array geometry is chosen for its similarity to an aircraft or missile nosecone. Performance capabilities are analyzed for a number of antenna performance parameters including scan volume, sidelobe levels, grating lobes, beamwidth, directivity, element count, and cross-polarization

P-115: A Novel Cost-Effective Energy Recovery Sustaining Driver for Plasma Display Panel

A novel cost-effective energy recovery sustaining driver for AC plasma display panel is presented in this paper. The element counts can be minimized by appropriate switching sequence. Experimental results show switching losses and current stress on switches can be reduced significantly so that the efficiency is increased.

Cultural Similarities and Differences in the Design of University Web sites

This study examines cultural differences and similarities in design of university Web sites using Hofstede’s model of cultural dimensions. Graphical elements on a sample of university home pages from Malaysia, Austria, the United States, Ecuador, Japan, Sweden, Greece and Denmark are compared using content analysis methods. The home pages were analyzed on the basis of two criteria: organization and graphical design. Element frequency scores were correlated with Hofstede’s indexes and interpreted on the basis of the existing literature. The results suggest that similarities and differences in Web site design can be brought out through Hofstede’s cultural model. Computed correlations between Hofstede’s scores and frequency counts of interface elements were weaker than anticipated, but in most cases occurred in the hypothesized direction.

Pyroelectric IR sensor arrays for fall detection in the older population

Uncooled pyroelectric sensor arrays have been studied over many years for their uses in thermal imaging applications. These arrays will only detect changes in IR flux and so systems based upon them are very good at detecting movements of people in the scene without sensing the background, if they are used in staring mode. Relatively-low element count arrays (16x 16) can be used for a variety of people sensing applications, including people counting (for safety applications), queue monitoring etc. With appropriate signal processing such systems can be also be used for the detection of particular events such as a person falling over. There is a considerable need for automatic fall detection amongst older people, but there are important limitations to some of the current and emerging technologies available for this. Simple sensors, such as I or 2 element pyroelectric infra-red sensors provide crude data that is difficult to interpret; the use of devices worn on the person, such as wrist communicator and motion detectors have potential, but are reliant on the person being able and willing to wear the device; video cameras may be seen as intrusive and require considerable human resources to monitor activity while machine-interpretation of camera images is complex and may be difficult in this application area. The use of a pyroelectric thermal array sensor was seen to have a number of potential benefits. The sensor is wall-mounted and does not require the user to wear a device. It enables detailed analysis of a subject's motion to be achieved locally, within the detector, using only a modest processor. This is possible due to the relative ease with which data from the sensor can be interpreted relative to the data generated by alternative sensors such as video devices. In addition to the cost-effectiveness of this solution, it was felt that the lack of detail in the low-level data, together with the elimination of the need to transmit data outside the detector, would help to avert feelings intrusiveness on the part of the end-user. The main benefits of this type of technology would be for older people who spend time alone in unsupervised environments. This would include people living alone in ordinary housing or in sheltered accommodation (apartment complexes for older people with local warden) and non-communal areas in residential/nursing home environments (e.g. bedrooms and ensuite bathrooms and toilets). This paper will review the development of the array, the pyroelectric ceramic material upon which it is based and the system capabilities. It will present results from the Framework 5 SIMBAD project, which used the system to monitor the movements of elderly people over a considerable period of time.

The Need for Evidence-Based Quality Assurance in the Modern Ultrasound Clinical Laboratory

A quick review of the specification sheets for new technologically intensive diagnostic ultrasound systems reveals a substantial number of fairly impressive operational performance claims. In at least one manufacturer's published material, the system specifications boasts of a dynamic range of 180 dB. To put that number in perspective, a device capable of 180 dB of dynamic range of resolution would be able to detect the flutter of a butterfly's wing in the middle of a thermonuclear explosion. How does one verify such an astounding performance claim using currently available ultrasound testing devices such as a tissue-mimicking phantom and what is the explicit clinical significance of such dynamic range? Additionally, while most of us were focused with amazement in leapfrog advances in system technology, diagnostic ultrasound transducers were also undergoing radical changes in array material composition and design. Most modern composite transducer specifications claim fractional bandwidths of 85%, and more and element counts as high as 2500. While the great technological strides made in ultrasound system design have been impressive, all of the computational and processing power of the 'all-digital' ultrasound device is singularly dependent on the output and input characteristics of the ultrasound transducer. Published data shows that the ultrasound transducer is subject to degradation in performance, as well as element failure, potentially leading to patient misdiagnosis or under-diagnosis. The need to regularly test transducers for performance variances will be explored within this paper. Additionally, the key areas of transducer performance as they relate to image and Doppler quality will be defined.