Block Row Research Articles

Privacy-preserving linear and nonlinear approximation via linear programming

We propose a novel privacy-preserving random kernel approximation based on a data matrix A∈R m×n whose rows are divided into privately owned blocks. Each block of rows belongs to a different entity that is unwilling to share its rows or make them public. We wish to obtain an accurate function approximation for a given y∈R m corresponding to each of the m rows of A. Our approximation of y is a real function on R n evaluated at each row of A and is based on the concept of a reduced kernel K(A, B′), where B′ is the transpose of a completely random matrix B. The proposed linear-programming-based approximation, which is public but does not reveal the privately held data matrix A, has accuracy comparable to that of an ordinary kernel approximation based on a publicly disclosed data matrix A.

Accounting for variation in designing greenhouse experiments with special reference to greenhouses containing plants on conveyor systems

BackgroundThere are a number of unresolved issues in the design of experiments in greenhouses. They include whether statistical designs should be used and, if so, which designs should be used. Also, are there thigmomorphogenic or other effects arising from the movement of plants on conveyor belts within a greenhouse? A two-phase, single-line wheat experiment involving four tactics was conducted in a conventional greenhouse and a fully-automated phenotyping greenhouse (Smarthouse) to investigate these issues.Results and discussionAnalyses of our experiment show that there was a small east–west trend in total area of the plants in the Smarthouse. Analyses of the data from three multiline experiments reveal a large north–south trend. In the single-line experiment, there was no evidence of differences between trios of lanes, nor of movement effects. Swapping plant positions during the trial was found to decrease the east–west trend, but at the cost of increased error variance. The movement of plants in a north–south direction, through a shaded area for an equal amount of time, nullified the north–south trend. An investigation of alternative experimental designs for equally-replicated experiments revealed that generally designs with smaller blocks performed best, but that (nearly) trend-free designs can be effective when blocks are larger.ConclusionsTo account for variation in microclimate in a greenhouse, using statistical design and analysis is better than rearranging the position of plants during the experiment. For the relocation of plants to be successful requires that plants spend an equal amount of time in each microclimate, preferably during comparable growth stages. Even then, there is no evidence that this will be any more precise than statistical design and analysis of the experiment, and the risk is that it will not be successful at all. As for statistical design and analysis, it is best to use either (i) smaller blocks, (ii) (nearly) trend-free arrangement of treatments with a linear trend term included in the analysis, or, as a last resort, (iii) blocks of several complete rows with trend terms in the analysis. Also, we recommend that the greenhouse arrangement parallel that in the Smarthouse, but with randomization where appropriate.

Stability of granite drystone masonry retaining walls: I. Analytical design

A limit-equilibrium-based technique is proposed for the design and analysis of drystone masonry retaining walls, focusing particularly on granite walls as traditionally constructed in Galicia in northwest Spain. To date, walls have typically been designed on the basis of past experience and rigid wall approaches. The method presented analyses wall stability, at different heights associated with block rows, against sliding and against two overturning mechanisms. As a result, design widths are obtained for different wall depths. The method can also be applied to estimates of the stability of existing walls with known dimensions and properties. The analytical method was applied experimentally to the design of a 20 m high wall. A sensitivity analysis of the design was also performed, with results presented in the form of a spider diagram. Estimates of the most relevant parameters for this type of design and some back-analyses to assess the technique are addressed in an accompanying paper.

Revisiting parallel cyclic reduction and parallel prefix-based algorithms for block tridiagonal systems of equations

Direct solvers based on prefix computation and cyclic reduction algorithms exploit the special structure of tridiagonal systems of equations to deliver better parallel performance compared to those designed for more general systems of equations. This performance advantage is even more pronounced for block tridiagonal systems. In this paper, we re-examine the performances of these two algorithms taking the effects of block size into account. Depending on the block size, the parameter space spanned by the number of block rows, size of the blocks and the processor count is shown to favor one or the other of the two algorithms. A critical block size that separates these two regions is shown to emerge and its dependence both on problem dependent parameters and on machine-specific constants is established. Empirical verification of these analytical findings is carried out on up to 2048 cores of a Cray XT4 system.

The Baffle Blocks Effects of Pressure Characteristics on USBR III Basin Floor

The principle of energy dissipation in stilling basin is based on hydraulic jump formation. Due to the inherent fluctuating characteristic of the hydraulic jump, basin floor is subjected to variations of pressure, resulting in unstableness due to uplift forces. To increase the efficiency of the stilling basins and improve the energy dissipation rate, one or two rows of baffle blocks are applied on the basin floor. Causing a forced hydraulic jump, tension and compression forces are exerted by pressure fluctuations of rotating roller zone of hydraulic jump. In this investigation, to observe the impacts of baffle blocks on pressure fluctuations on basin floor, a standard USBR basin model type III was constructed, and then a second row of blocks was added to the basin. A set of pressure tubes was fixed along the axis of the basin to measure the static and dynamic pressures on basin floor. The results were expressed in dimensionless parameters including C-p, C+p, C’p, Cp. Also, power spectra of pressure fluctuations were calculated. The results show a decreasing trend in root mean square of pressure fluctuations as distancing from toe of jump along the basin with and without baffle blocks. Also, mean pressure increases when water jet strokes the basin then decreases under roller zone of jump and increases again after sequent depth. The spectral analysis indicates that the dominant frequency is between 10 rad/s and 35 rad/s and pressure fluctuations have low frequency characteristics.

High Hardware Utilization and Low Memory Block Requirement Decoding of QC-LDPC Codes

This paper presents a simple yet effective decoding for general quasi-cyclic low-density parity-check (QC-LDPC) codes, which not only achieves high hardware utility efficiency (HUE), but also brings about great memory block reduction without any performance degradation. The main idea is to split the check matrix into several row blocks, then to perform the improved message passing computations sequentially block by block. As the decoding algorithm improves, the sequential tie between the two-phase computations is broken, so that the two-phase computations can be overlapped which bring in high HUE. Two overlapping schemes are also presented, each of which suits a different situation. In addition, an efficient memory arrangement scheme is proposed to reduce the great memory block requirement of the LDPC decoder. As an example, for the 0.4 rate LDPC code selected from Chinese Digital TV Terrestrial Broadcasting (DTTB), our decoding saves over 80% memory blocks compared with the conventional decoding, and the decoder achieves 0.97 HUE. Finally, the 0.4 rate LDPC decoder is implemented on an FPGA device EP2S30 (speed grade −5). Using 8 row processing units, the decoder can achieve a maximum net throughput of 28.5 Mbps at 20 iterations.

Codling moth, Cydia pomonella L., colonisation of a newly-planted organic pome fruit orchard in Central Otago, New Zealand, and methods of pest management over the first ten years

An organic orchard was planted at the Clyde Research Centre, Central Otago, from 1991 to 1993 on land not previously used for fruit-growing. The orchard comprised nine discrete 0.22ha well-sheltered apple (Malus domestica Borkh.) and pear (Pyrus communis L.) cultivar blocks with wide headlands, in a total land area of 3ha. Colonisation of the orchard by codling moth (Cydia pomonella L.) was monitored using pheromone traps and by recording larval damage to the fruit, initially, from examination of the entire crop of all the trees, then later a sample of the trees whose locations were noted. This facilitated a 3-dimensional record of orchard colonisation. Detailed examination of damage enabled estimation of the numbers of damaging larvae, their mortality in the fruit, and the numbers of larvae which survived to seek cocooning sites. A low density of 3–6 female codling moths was estimated to be present in the 2ha of planted orchard area in the first cropping season (1993–94). A major increase in trap catches and larval damage in 1995–96 prompted the application of mating disruption in the following years. Although successful in reducing the population for the first two seasons, codling moth then increased again and granulosis virus (CMGV) was added to the management programme. Three full rate sprays of the CMGV applied to the three central rows of each cultivar block in 1998–99 halved the percentage of fruit with surviving larvae to 0.7% in the treated trees. This fell to 0.2% in 1999–2000 following 13 applications of CMGV at 1/5th rate to the whole orchard. In 2000–01, when mating disruption was again used alone against a low density population, only one surviving larva was found in a sample of 11,841 fruits (0.05%). The complementary management options provided by mating disruption and CMGV are discussed, as well as the importance of minimising the sources of immigrant codling moths near organic orchards.

Equilibrium problem for the eigenvalues of banded block Toeplitz matrices

AbstractWe consider banded block Toeplitz matrices Tn with n block rows and columns. We show that under certain technical assumptions, the normalized eigenvalue counting measure of Tn for n → ∞ weakly converges to one component of the unique vector of measures that minimizes a certain energy functional. In this way we generalize a recent result of Duits and Kuijlaars for the scalar case. Along the way we also obtain an equilibrium problem associated to an arbitrary algebraic curve, not necessarily related to a block Toeplitz matrix.For banded block Toeplitz matrices, there are several new phenomena that do not occur in the scalar case: (i) The total masses of the equilibrium measures do not necessarily form a simple arithmetic series but in general are obtained through a combinatorial rule; (ii) The limiting eigenvalue distribution may contain point masses, and there may be attracting point sources in the equilibrium problem; (iii) More seriously, there are examples where the connection between the limiting eigenvalue distribution of Tn and the solution to the equilibrium problem breaks down. We provide sufficient conditions guaranteeing that no such breakdown occurs; in particular we show this if Tn is a Hessenberg matrix.

Efficient Built-In Self-Repair Techniques for Multiple Repairable Embedded RAMs

In this paper, efficient built-in self-repair (BISR) techniques for multiple repairable memory cores with different sizes and divided redundancy mechanisms are proposed. Embedded memory cores are first partitioned into memory groups. For each memory group, a redundant memory module is added and divided into row blocks and column blocks. Moreover, the memory cores within a memory group are partitioned into divided arrays (consisting of row/column blocks) of the same size. The redundant memory can be shared among all memory cores within the same memory group. Therefore, unlike the traditional redundancy architectures, a row (column) block is used as the basic replacement element. Based on the proposed redundancy architecture, a heuristic heterogeneous extended spare pivoting redundancy analysis algorithm suitable for built-in implementation is also proposed. Experimental results show that the repair rate and manufacturing yield can be improved significantly due to the efficient usage of redundancy. Moreover, the area overhead of the BISR circuitry for an example memory group consisting of four memory instances of size 9.25 Mbits is only 1.12%.

Dynamic Space and Time Partitioning for Yard Crane Workload Management in Container Terminals

We propose a new hierarchical scheme for yard crane (YC) workload management in container terminals. We also propose a time partitioning algorithm and a space partitioning algorithm for deploying YCs to handle changing job arrival patterns in a row of yard blocks. The main differences between our approach and most of the methods in literature are (1) the average vehicle job waiting time instead of the number of jobs is used to balance YC workload and to evaluate the quality of a partition, (2) the YC working zone assignment is not in units of yard blocks and our space partitioning algorithm generates more flexible divisions of the workload from all blocks, and (3) the YC deployment frequency is not fixed but is decided by our time partitioning algorithm with the objective of minimizing average vehicle waiting times. The scheme combines simulation and optimization to achieve our objective for a row of yard blocks. Experimental results show that the proposed binary partitioning algorithm TP2 makes substantial improvements in job waiting times over the basic partitioning scheme and another existing algorithm (Ng, W. C. 2005. Crane scheduling in container yards with intercrane interference. Eur. J. Oper. Res. 164(1) 64–78) in all tested job arrival scenarios.

Asymptotic properties of random matrices and pseudomatrices

We study the asymptotics of sums of matricially free random variables, called random pseudomatrices, and we compare it with that of random matrices with block-identical variances. For objects of both types we find the limit joint distributions of blocks and give their Hilbert space realizations, using operators called ‘matricially free Gaussian operators’. In particular, if the variance matrices are symmetric, the asymptotics of symmetric blocks of random pseudomatrices agrees with that of symmetric random blocks. We also show that blocks of random pseudomatrices are ‘asymptotically matricially free’ whereas the corresponding symmetric random blocks are ‘asymptotically symmetrically matricially free’, where symmetric matricial freeness is obtained from matricial freeness by an operation of symmetrization. Finally, we show that row blocks of square, block-lower-triangular and block-diagonal pseudomatrices are asymptotically free, monotone independent and boolean independent, respectively.

Parallel direct methods for solving the system of linear equations with pipelining on a multicore using OpenMP

Recent developments in high performance computer architecture have a significant effect on all fields of scientific computing. Linear algebra and especially the solution of linear systems of equations lie at the heart of many applications in scientific computing. This paper describes and analyzes three parallel versions of the dense direct methods such as the Gaussian elimination method and the LU form of Gaussian elimination that are used in linear system solving on a multicore using an OpenMP interface. More specifically, we present two naive parallel algorithms based on row block and row cyclic data distribution and we put special emphasis on presenting a third parallel algorithm based on the pipeline technique. Further, we propose an implementation of the pipelining technique in OpenMP. Experimental results on a multicore CPU show that the proposed OpenMP pipeline implementation achieves good overall performance compared to the other two naive parallel methods. Finally, in this work we propose a simple, fast and reasonably analytical model to predict the performance of the direct methods with the pipelining technique.

Parallel Multithreaded Processing for Data Set Summarization on Multicore CPUs

Data mining algorithms should exploit new hardware technologies to accelerate computations. Such goal is difficult to achieve in database management system (DBMS) due to its complex internal subsystems and because data mining numeric computations of large data sets are difficult to optimize. This paper explores taking advantage of existing multithreaded capabilities of multicore CPUs as well as caching in RAM memory to efficiently compute summaries of a large data set, a fundamental data mining problem. We introduce parallel algorithms working on multiple threads, which overcome the row aggregation processing bottleneck of accessing secondary storage, while maintaining linear time complexity with respect to data set size. Our proposal is based on a combination of table scans and parallel multithreaded processing among multiple cores in the CPU. We introduce several database-style and hardware-level optimizations: caching row blocks of the input table, managing available RAM memory, interleaving I/O and CPU processing, as well as tuning the number of working threads. We experimentally benchmark our algorithms with large data sets on a DBMS running on a computer with a multicore CPU. We show that our algorithms outperform existing DBMS mechanisms in computing aggregations of multidimensional data summaries, especially as dimensionality grows. Furthermore, we show that local memory allocation (RAM block size) does not have a significant impact when the thread management algorithm distributes the workload among a fixed number of threads. Our proposal is unique in the sense that we do not modify or require access to the DBMS source code, but instead, we extend the DBMS with analytic functionality by developing User-Defined Functions.

Construction of multiple-rate quasi-cyclic LDPC codes via the hyperplane decomposing

This paper presents an approach to the construction of multiple-rate quasi-cyclic low-density parity-check (LDPC) codes. Parity-check matrices of the proposed codes consist of q X q square submatrices. The block rows and block columns of the parity-check matrix correspond to the hyperplanes (μ-flats) and points in Euclidean geometries, respectively. By decomposing the μ -flats, we obtain LDPC codes of different code rates and a constant code length. The code performance is investigated in term of the bit error rate and compared with those of LDPC codes given in IEEE standards. Simulation results show that our codes perform very well and have low error floors over the additive white Gaussian noise channel.

On Kaczmarz’s projection iteration as a direct solver for linear least squares problems

In this paper we construct and theoretically analyze a class of direct projection algorithms for the numerical solution of linear least squares problems. These algorithms are obtained by adding supplementary directions for projection, constructed as linear combinations of the initial system rows and columns, in Kaczmarz and Extended Kaczmarz iterative methods. The above ideas are extended to the block row and column versions of the previously mentioned methods. The developed algorithms are then compared with other direct projection-based methods by the application to problems arising in multibody elasticity.

A New Uniform Theory of Diffraction Based Model for Multiple Building Diffraction in the Presence of Trees

In this article, the uniform theory of diffraction is the base of multiple diffraction loss calculation by buildings. The path loss is derived and analyzed on the basis that buildings are parallel rows of dielectric blocks, having rectangular shapes and being flat roofed with the same heights and spacing. As far as the path loss calculation is concerned, the above assumption leads to more realistic results, since previous studies are limited to the simplified models in which buildings are approximated as absorbing half-screens, perfect conducting half-screens (knife-edges), or 90° wedges. In addition, this study endeavored to extend this model to include higher-order terms for reflection coefficients as well as considering tree effects. In this way, it was assumed that apart from the high-rise urban core, buildings have nearly the same height and spacing and are organized by street systems into rows; also, the trees are assumed to be situated next to the buildings. The canopies of trees are modeled as discrete ensembles of leaves and branches. The comparison between the model and measurement data shows that including tree effects provides reasonable and convincing predictions.

Asymptotic Properties of Bias Compensated State Space Model Identification Method

AbstractThe authors proposes a bias-compensated state space model identification (BCSS) method in order to relax the order of the persistent excitation (PE) condition. Most of the subspace identification methods utilize instrumental variables (IV) to obtain an unbiased estimate while the proposed method introduces a bias compensation technique to the Ordinary MOESP type method. In this paper, S/N ratios of certain matrices in the proposed method and the PI-MOESP method are analyzed and compared. It is shown that the S/N ratio in the proposed method is better than that in the PI-MOESP method especially when a pole of the plant is near 1 and the number of the block rows of the IV matrix is small.

Retrieval of Images Using DCT and DCT Wavelet Over Image Blocks

This paper introduces a new CBIR system based on two different approaches in order to achieve the retrieval efficiency and accuracy. Color and texture information is extracted and used in this work to form the feature vector. To do the texture feature extraction this system uses DCT and DCT Wavelet transform to generate the feature vectors of the query and database images. Color information extraction process includes separation of image into R, G and B planes. Further each plane is divided into 4 blocks and for each block row mean vectors are calculated. DCT and DCT wavelet is applied over row mean vector of each block separately and 4 sets of DCT and DCT wavelet coefficients are obtained respectively. Out of these few coefficients are selected from each block and arranged in consecutive order to form the feature vector of the image. Variable size feature vectors are formed by changing the no of coefficients selected from each row vector. Total 18 different sets are obtained by changing the no of coefficients selected from each block. These two different feature databases obtained using DCT and DCT wavelet are then tested using 100 query images from 10 different categories. Euclidean distance is used as similarity measure to compare the image features. Euclidean distance calculated is sorted into ascending order and cluster of first 100 images is selected to count the images which are relevant to the query image. Results are further refined using second level thresholding which uses three criteria which can be applied to first level results. Results obtained are showing the better performance by DCT wavelet as compare to DCT transform. Keywords-component; DCT; DCT wavelet; Eucidean distance. I. INTRODUCTION Large amount of images are being generated, stored and used daily in various real life applications through various fields like engineering, medical sciences, biometrics, architectural designs and drawings and many other areas. Although various techniques are being designed and used to store the images efficiently, still it demands to search new effective and accurate techniques to retrieve these images easily from large volume of databases. Text based image retrieval techniques have tried in this direction which has got many constraints and drawbacks associated with it which is continuously encouraging the researchers to come up with the new techniques to retrieve the images based on contents instead of text annotations. Image contents are broadly classified into global and local contents. Local contents define the local attributes of the image like color, shape and texture

TRIALS ON THE USE OF NETS IN THE VIGNOLA CHERRY DISTRICT AGAINST CHERRY FRUIT FLY (RHAGOLETIS CERASI L.)

In the Vignola cherry district, wrapping trees with nets to protect against cherry fruit fly (Rhagoletis cerasi) infestation has been tested since 2001. In initial trials (2001-2003), individual trees were wrapped with nets. In 2007-2008, blocks of tree rows were wrapped for different periods. Although this investigation has shown the suitability of this defence strategy for the complete prevention of the damage due to R. cerasi, it has to be considered that the net has to be positioned as early as possible after the first capture of adult fly and the treatment is effective only if the trees are covered till the fruit harvest. Other quality parameters of cherries do not seem to be seriously affected by the net, although a genotype influence is evidenced.

BCYCLIC: A parallel block tridiagonal matrix cyclic solver

A block tridiagonal matrix is factored with minimal fill-in using a cyclic reduction algorithm that is easily parallelized. Storage of the factored blocks allows the application of the inverse to multiple right-hand sides which may not be known at factorization time. Scalability with the number of block rows is achieved with cyclic reduction, while scalability with the block size is achieved using multithreaded routines (OpenMP, GotoBLAS) for block matrix manipulation. This dual scalability is a noteworthy feature of this new solver, as well as its ability to efficiently handle arbitrary (non-powers-of-2) block row and processor numbers. Comparison with a state-of-the art parallel sparse solver is presented. It is expected that this new solver will allow many physical applications to optimally use the parallel resources on current supercomputers. Example usage of the solver in magneto-hydrodynamic (MHD), three-dimensional equilibrium solvers for high-temperature fusion plasmas is cited.