Large Number Of Pieces Research Articles

Array Antenna Pattern Synthesis using Improved Particle Swarm Optimization (IPSO) Algorithm

Antenna arrays are used in many different systems, including radar, military systems, and wireless communications. The design of the antenna array has a significant impact on how well the communication system performs. The large number of pieces and the large sidelobe levels provide the biggest design hurdles for such arrays. The antenna arrays have recently been heavily thinned using optimization approaches that take advantage of evolutionary algorithms in order to lower power consumption and enhance the radiation pattern by lowering sidelobe levels. A global optimum for this kind of algorithm is not guaranteed, though, because of the stochastic nature of the resolution techniques. This work characterizes the optimal pattern synthesis of a linear array antenna using the Improved Particle Swarm Optimization (IPSO) algorithm. The main aim is to obtain a low Side Lobe Level (SLL) that avoids interference and a narrow beam width for acquiring high directivity to obtain the optimal solution established on the action of the swarm that adopts the fitness function. To achieve these targets, we analyze the optimization of the excitation amplitude and inter-element spacing of the array. In this article, we have presented the optimal power pattern obtained by two different types of excitation amplitude distributions for both uniformly spaced linear arrays and non-uniformly spaced linear arrays. In the first case of amplitude distribution, namely, non-uniform distribution of excitation amplitude, synthesis of the array pattern for three different values of inter-element spacing as well as optimized spacing are presented for different array sizes. In the second case, optimal thinning of a uniformly spaced array as well as a non-uniformly spaced (optimized) array has been presented. The IPSO algorithm provides a radiation pattern that is used to determine the set of antenna array parameters. The design of an antenna array using the IPSO algorithm gives significant enhancements when compared with a uniformly excited and uniformly spaced array. The flexibility as well as ease of implementation of the IPSO algorithm are evident from this analysis, showing the algorithm’s usefulness in electromagnetic optimization problems.

Bassoon in the 16–17 centuries: the issues of the bassoon practice development

Bassoon in the 16–17 centuries: the issues of the bassoon practice development

Compressing Chinese Dark Chess Endgame Databases by Deep Learning

Endgame databases can be difficult to use in tree search when database sizes remain large even after compression. Given the same endgame, we discover that the compression ratios vary significantly when using different encoding schemes. The intuition is that when a set of positions mapped into a continuous chunk of segments have similar values, block-based compression libraries such as zlib can yield a better compression ratio than cases where segments contain diversified values. However, finding the optimal encoding scheme by exhaustive enumeration is time-infeasible for endgame databases with a large number of pieces. We propose a novel approach using deep learning to obtain an encoding scheme so that the compression ratio is suitable for practical purposes. Our approach can be applied to chess-like games.

Effect of disorder on the spatial structure of damage in slowly compressed porous rocks.

Faults and damage zone properties control a range of important phenomena, from the hydraulic properties of underground reservoirs to the physics of earthquakes on a larger scale. Here, we investigate the effect of disorder of porous rocks on the spatial structure of damage emerging under compression. Model rock samples are numerically generated by sedimenting particles where the amount of disorder is controlled by the particle size distribution. To obtain damage bands with a sufficiently large length along axis, we performed simulations of 'Brazilian'-type compression tests of cylindrical samples. As failure is approached, damage localization leads to the formation of two conjugate shear bands. The orientation angle of bands to the loading direction increases with disorder, implying a decrease in the internal coefficient of friction. The width of the damage band scales as a power law of the degree of disorder. Inside the damage band, the sample is crushed into a large number of pieces with a power law mass distribution. The shape of fragments undergoes a crossover at a disorder-dependent size from the isotropy of small pieces to the anisotropic flattened form of the large ones. The results provide important constraints in understanding the role of disorder in geological fractures.This article is part of the theme issue 'Statistical physics of fracture and earthquakes'.

Transition from Straight to Fractal Cracks due to Projectile Penetration

We present a theoretical study of the fracture of two-dimensional disc-shaped samples due to projectile penetration focusing on the geometrical structure of the crack pattern. The penetration of a cone is simulated into a plate of circular shape using a discrete element model of heterogeneous brittle materials varying the speed of penetration in a broad range. As the cone penetrates a destroyed zone is created from which cracks run to the external boundary of the plate. Computer simulations revealed that in the low speed limit of loading two cracks are generated with nearly straight shape. Increasing the penetration speed the crack pattern remains regular, however, both the number of cracks and their fractal dimension increases. High speed penetration gives rise to a crack network such that the sample gets fragmented into a large number of pieces. We give a quantitative analysis of the evolution of the system from simple cracking through fractal cracks to fragmentation with a connected crack network.

Thomas Mulliner revived

The keyboard manuscript known as the Mulliner Book (British Library, Add. Ms.30513) has long been recognized as a major source of English music of the mid-16th century. It contains a particularly large number of pieces by John Redford, pointing to a strong connection with musicians at St Paul's Cathedral, alongside sizable quantities of music by other important near-contemporaries such as Thomas Tallis, John Blytheman and John Sheppard. The contents of the manuscript were first published in their entirety 60 years ago, edited by Denis Stevens, the 120 keyboard pieces appearing as the first volume in the Musica Britannica series (1951, revised 1954), while eleven pieces for cittern and gittern were published as an appendix, transcribed into staff notation, in Stevens's The Mulliner Book: a commentary (London, 1952). Stevens was the first to recognize the full importance of the manuscript, drawing attention to the fact that it is the sole source for a large proportion of its music. Although the Commentary was published in a limited edition of 500, alongside the edition itself it proved influential. It was the first attempt to study the entire contents of the manuscript in detail (a plea for such a study had been made by Charles Van Den Borren 40 years previously in The sources of keyboard music in England, trans. James E. Matthew (London, 1913), p.11), covering a wide range of topics. For example, it discusses the authorship of the pieces, the extensive use of cantus firmus technique, and matters of textual criticism. Stevens also drew attention to a large body of ‘concordant’ sources, especially for non-keyboard versions of the pieces. This offered, in some instances, the opportunity for considering a repertory of ‘lost’ polyphonic vocal music, elsewhere preserved imperfectly or not at all. Indeed, in an article prompted by the two publications, Edward Lowinsky wrote that: ‘Undoubtedly the Mulliner Book is going to play a significant part in any future history of English song’ (‘English organ music of the Renaissance’, Musical Quarterly, xxxix (1953), pp.373–95, 528–53, at p.376).

Physical Properties Giving the Sensory Perception of Whey Proteins/Polysaccharide Gels

Establishing relationships between physical and sensorial properties of semi-solid foods is essential to develop tailored products. Whey protein/polysaccharide mixed gels were used to model both natural and fabricated semi-solid foods. The presence of various polysaccharides modulated the microstructure and large deformation properties of the mixed gels. The gels exhibited a large spectrum of sensorial properties as evaluated by panellists in a quantitative descriptive analysis. Mouthfeel attributes that discriminated best between the gels were wateriness, crumbliness, and spreadability. Wateriness strongly correlated with the amount of exuded phase (serum) measured during uniaxial compression. Serum release may have a positive effect on, for instance, the juiciness of a product. Large deformation measurements showed that highly crumbly gels fracture readily via a free-running crack. Low serum release is a requirement for that. Low crumbly gels fracture slowly, often releasing a high amount of serum. Spreadability related to the occurrence of multiple microcracks during deformation as observed by confocal laser scanning microscopy, which resulted in a large number of pieces after oral processing.

A Coevolutionary Approach to Analyzing Supply Function Equilibrium Model

This paper presents a coevolutionary approach to analyzing supply function equilibrium (SFE) models of an oligopolistic electricity market. Both the affine supply function model and the piece-wise affine supply function model are considered. Different parametrization cases of the affine supply function model are analyzed. The piece-wise affine supply functions that have a large number of pieces are used to numerically estimate the equilibrium supply functions of any shapes. Simulation cases of the piece-wise affine supply function model with different peak loads, nonquadratic and nonconvex costs, and different demand elasticities are studied. An example based on the cost data from the real-world electricity industry is used to validate the approach presented in this paper. Simulation results show that the coevolutionary approach rapidly converges to SFE in the affine supply function model simulation and robustly converges to SFE in all cases of the piece-wise affine supply function model simulation. The approach is robust and flexible and has the potential to be used to solve the complicated equilibrium problems in real-world electricity markets

Determinants of National Television News Coverage of Women in the House of Representatives, 1987-1998

This study adapts Timothy Cook's 1986 analysis of news coverage of members of Congress to women legislators. The relative impact of independent variables on the amount of television news coverage received by women in the House from 1987 to 1998 was determined using Poisson regression. These included structural variables (leadership, seniority, party control of the chamber, and membership on a prestigious committee), member characteristics (racial minority status, media market size, party and attractiveness), and member activities (legislative activity, ideology, scandal, authorship of women's bills, and running for higher office). Factors that were significantly related to the amount of coverage received by a congresswoman were: authorship of women's bills, running for higher office, media market size, political party, and seniority. Leadership did not have the same payoff for women's visibility that it did for the largely male group of legislators in Cook's study. Authoring a large number of pieces of legislation did not enhance women's coverage, but authoring bills on women's issues did.

Load‐adapted 3D‐reinforcement by means of function‐adjusted ready‐making process

Complex material requirements for high‐technology applications increasingly demand the use of hybrid material structures with properties tailored to the lines of loading. Textile‐reinforced multilayer composite structures are particularly suitable for the production of component structures in an optimised lightweight construction. In the loading case, however, delaminating phenomena occur between the individual layers due to the low interlaminar shear strength. The appropriate techniques and machines of the ready‐made‐clothing technology allow the specific sewing‐up of the semifinished textile products into a three‐dimensionally reinforced multilayer composite structure; the setting of a load‐adapted and failure‐tolerant characteristic of properties being possible in the z‐direction through a versatile variation of sewing parameters. Moreover, the sewing technology makes possible a ready‐made‐clothing‐technological preassembly of components of semi‐finished products, and thus can perform position‐fixing functions in the consolidation of the composites. The ready‐made‐clothing process is divided into sub‐processes like product development, preparation of cutting, cutting, connecting and forming as well as packaging and shipping. The technical procedures and machines applied are chosen from economic aspects. Besides the large number of pieces, extreme thickness of the textile products of up to 20 mm and the required sewing precision demand precise and reproducible manufacturing processes.

Roman armour and metalworking at Carlisle, Cumbria, England

Recent excavations at the Roman fort in Carlisle, Cumbria, have yielded a large number of pieces of articulated Roman armour and other items. This is the most important such find in Britain since the Corbridge hoard was excavated in 1964 (Allason-Jones & Bishop 1988).On the north side of the via principalis adjacent to the headquarters building (principia), the corner of a timber building was uncovered (FIGURE 2). On the floor was a quantity of articulated and disarticulated fragments of predominantly ferrous Roman armour, including as many as three crushed, but complete, laminated arm defences. Although first used by Hellenistic cavalry and referred to in Xenophon’s Art of horsemanship (XI.13-XII.5), and later used by gladiators, this type of armour was adopted by Roman legionaries. It was once thought that armguards (manicae) were very rare and only employed under special circumstances, such as Trajan’s wars in Dacia where they were used to counter the deadly scythe-like falx (Richmond 1982: 49–50). A number of similar finds have been made, as at Newstead (Curle 1911: plate XXIII) and Richborough, Kent (M. Lyne pers. comm.), but they are often isolated and the pieces crushed, making reconstruction difficult and speculative. A graffito from Dura-Europos (FIGURE 1) shows a mounted soldier with a tall helmet and a mail or scale neck-guard, with similar limb and abdominal defences (Robinson 1975: figure 190). The Carlisle assemblage is important for the retrieval of articulated pieces, with associated copper-alloy rivets and leather.

Andries Bongcn (ca. 1732-1792) en de Franse invloed op de Amsterdamse kastenmakerij in de tweede helft van de achttiende eeuw

Andries Bongcn (ca. 1732-1792) en de Franse invloed op de Amsterdamse kastenmakerij in de tweede helft van de achttiende eeuw

An Application of Graph Theory and Integer Programming: Chessboard Non-attacking Puzzles

not yet part of the usual undergraduate mathematics curriculum but of growing importance in industrial mathematics: maximal cliques from graph theory and 0-1 integer programming. Consider a regular chessboard and the five chess pieces: rook (castle), bishop, knight, king, and queen. In the game of chess each player begins with two of each of the first three of those pieces and one each of the last two. A large collection of puzzles can be posed on the chessboard in which a person is assumed to have a large number of pieces of one type and none of the others. One problem is to decide how to place the maximum number of pieces of the same kind on the board (no more than one to a square) so that no capturing can occur if the pieces are played according to the usual legal moves. As an example, let's consider the rook puzzle. We wish to place as many rooks as possible on the chessboard so that no two attack each other. A rook moves orthogonally, that is, through any number of unoccupied squares parallel to an edge of the board. Thus once a rook is placed it will not be possible to place another on the same rank (row of horizontal squares) or file (column of vertical squares). Thus the problem reduces to finding a set of squares such that:

DISPERSION-HARDENING OF LAMINATED PLATINUM SHEET

By stacking together a large number of pieces of normal platinum sheet, hot forging to effect bonding followed by cold rolling, and repeating the process as often as necessary, laminated sheet with any desired nominal thickness of laminations can be obtained. The hardness and annealing characteristics of such material have been studied and the stress-rupture properties at 1450°C determined. The stress-rupture strength for a life of 100 h is a maximum with a nominal laminate thickness of ∼ 1000 Å. Introduction of thoria between the laminations does not increase the peak stress-rupture strength but makes the strength much less dependent on laminate thickness.