Normalised fuzzy index for research ranking

ABSTRACT

There are great interests of designing research metrics and indices to measure the research impacts in research institutes. Unfortunately, most of those indices ignore critical design issues, e.g. the disparity between domains, the impact of journals or conferences in which papers are published, normalising the range of the index values to certain intervals, and the scalability of using the index to rank different research entities. In this paper, a new normalised fuzzy index, (NF_index), is proposed as a fuzzy-based research impact metric. The proposed index is a scalable index whose values are normalised to the percentage levels. NF_index achieves both inter-discipline normalisation and intra-discipline consistency. The capability of NF_index to achieve the inter-discipline normalisation enables fair comparison between different research domains regardless their nature in terms of influence and contribution to other research areas, e.g. natural science. Therefore, NF_index gives a universal normalised single-number metric that can be used by research institutes to solve the problem of inter-discipline scholar ranking. Moreover, it can help universal ranking of universities and research institutes according to their research capabilities and impacts. The obtained results, on diverse research areas, prove the potential of NF_index in terms of both intra-discipline consistency and inter-discipline normalisation.     

The use of pressure mapping to assess the comfort of agricultural machinery seats

Interface pressure measurement gives an objective value to human comfort. Prolonged sitting is known to contribute to musculoskeletal disorders. Driving a tractor involves several actions such as steering, operating levers, buttons, brake and clutch pedals, and looking behind to observe and maneuver the machine. These operations affect sitting posture and create a pattern of loading on the structures of the operator's body.The aim of this study was to study barometric mapping at the operator's buttocks-seat interface for comfort evaluation of the agricultural and forestry machine seats. Three different tractor seats (A “low cost”; B “medium cost”; C “high cost”) were tested during ploughing, harrowing and haying operations, by 8 different operators. Two standardized conditions were used, one on a track with ridges and one on an asphalted surface, with driving tests conducted on both. From each test, the following values were obtained: maximum pressure peak (P_max); average pressure value (P_avg); and the average percentage of cells activated by pressures ranging between 50 and 130 g/cm² (NC_50-130), 131–400 g/cm² (NC_131-400) and higher than 400 g/cm² (NC_401-1000). Mean values of P_avg, P_max, NC_131-400, recorded after the two lab tests (on the road and the ridged track) carried out with seat-A tractors were greater (p < 0.05) than those obtained in tests with more comfortable seats (seats B and C). P_avg and P_max mean values recorded after three field tests carried out with A-seat tractors were greater than those obtained in tests with more comfortable seats (B and C). Similarly, the cell activation in the pressure interval 131–400 g/cm² (NC_131-400) in A-seat tests was significantly greater than that of both B and C seats. Based on our findings, it is possible to conclude that the analyzed pressure indexes in this study are useful instruments to describe the characteristics of seat mapping and compare agricultural machine seats as a function of operator's buttocks-seat interface, thus highlighting the comfort rate obtainable in dynamic situations by the operator.SummaryThe sitting posture is one of the main factors that contribute to musculoskeletal disorders. The methodology is based on barometric mapping for comfort evaluation. Tractors seats were tested in three agriculture operations and on two standardized tracks. The study showed indicators to evaluate barometric maps in dynamics conditions.     

The μ-basis of a planar rational curve—properties and computation

A moving line L(x,y;t)=0 is a family of lines with one parameter t in a plane. A moving line L(x,y;t)=0 is said to follow a rational curve P(t) if the point P(t₀) is on the line L(x,y;t₀)=0 for any parameter value t₀. A μ-basis of a rational curve P(t) is a pair of lowest degree moving lines that constitute a basis of the module formed by all the moving lines following P(t), which is the syzygy module of P(t). The study of moving lines, especially the μ-basis, has recently led to an efficient method, called the moving line method, for computing the implicit equation of a rational curve [3 and 6]. In this paper, we present properties and equivalent definitions of a μ-basis of a planar rational curve. Several of these properties and definitions are new, and they help to clarify an earlier definition of the μ-basis [3]. Furthermore, based on some of these newly established properties, an efficient algorithm is presented to compute a μ-basis of a planar rational curve. This algorithm applies vector elimination to the moving line module of P(t), and has O(n²) time complexity, where n is the degree of P(t). We show that the new algorithm is more efficient than the fastest previous algorithm [7].     

Can an off-the-rack orthotic stiletto alter pressure and comfort scores in the forefoot,arch and heel?

The study sought to investigate whether an orthotic stiletto could modulate the pressure and comfort under the forefoot, arch and heel that stiletto wearers experience. Twenty-two women participated. We measured the peak pressure and pressure-time integral for orthotic stilettos with built-in metatarsal pad, heel cup and arch support; standard stilettos without inlays; and trainers. Comfort was recorded during 3 × 3 working days. The orthotic stiletto exhibited lower metatarsal head1 (MTH) and MTH2+3 and heel pressures than the standard stiletto (p < .01), and a long second metatarsal increased MTH2+3 pressure (p < .01). The comfort in the forefoot and heel was higher in the orthotic stiletto than in the standard one (p < .01), and comfort in the forefoot was correlated to the pressure-time integral of MTH2+3 (p = .03) and not peak pressure. Off-the-rack orthotic stilettos can notably reduce plantar pressures and improve forefoot and heel comfort during everyday use.

Practitioner Summary: Off-the-rack orthotic stilettos with built-in metatarsal pad, arch support and heel caps can lower the pressure under the heel and forefoot in comparison with a standard stiletto and can improve comfort during everyday use. Having a long second metatarsal is a risk factor for increased forefoot pressure.     

Mechanistic investigation of the reactivity of disilene with nitrous oxide: A DFT study

We have reported the mechanistic investigation of the reaction of N₂O addition to disilene, trans-[(TMS)₂N(η¹-Me₅C₅)SiSi(η¹-Me₅C₅)N(TMS)₂] (1_t), employing density functional theory (BP86/TZVP//BP86/SVP) calculations. The potential energy surfaces of the title reaction are broadly classified under three pathways. Pathway I deals with the direct N₂O additions to 1_t affording the trans-dioxadisiletane ring compound P_t whereas in the same pathway we report a different bifurcation route from intermediate 2_t. This route portrays the isomerization of trans-monooxadisiletane species 2_t prior to the second N₂O addition, finally leading to the cis-isomeric product P_c. Different possibilities for isomerization of disilene 1_t to 1_c were studied in pathway II. The cis-disilene (1_c) formed can subsequently react with two N₂O molecules affording the cis-product P_c. Pathway III details the formation of silanone type intermediate 6, which subsequently combine with another silanone to afford loosely bound intermediates 7 and 8 respectively. The two separated silanone fragments in the isomeric intermediates 7 and 8 can then dimerizes to furnish the desired products. Among all the calculated potential energy surfaces, pathway III remains the most preferred route for disilene oxygenation under normal experimental condition. The present investigation about disilene reactivity will provide a deeper understanding on silylene chemistry and will exhibit promising applicability in main group chemistry as a whole.     

Symmetric Non-rigid Registration: A Geometric Theory and Some Numerical Techniques

This paper proposes ℒ₂- and information-theory-based (IT) non-rigid registration algorithms that are exactly symmetric. Such algorithms pair the same points of two images after the images are swapped. Many commonly-used ℒ₂ and IT non-rigid registration algorithms are only approximately symmetric. The asymmetry is due to the objective function as well as due to the numerical techniques used in discretizing and minimizing the objective function. This paper analyzes and provides techniques to eliminate both sources of asymmetry. This paper has five parts. The first part shows that objective function asymmetry is due to the use of standard differential volume forms on the domain of the images. The second part proposes alternate volume forms that completely eliminate objective function asymmetry. These forms, called graph-based volume forms, are naturally defined on the graph of the registration diffeomorphism f, rather than on the domain of f. When pulled back to the domain of f they involve the Jacobian J _f and therefore appear “non-standard”. In the third part of the paper, graph-based volume forms are analyzed in terms of four key objective-function properties: symmetry, positive-definiteness, invariance, and lack of bias. Graph-based volume forms whose associated ℒ₂ objective functions have the first three properties are completely classified. There is an infinite-dimensional space of such graph-based forms. But within this space, up to scalar multiple, there is a unique volume form whose associated ℒ₂ objective function is unbiased. This volume form, which when pulled back to the domain of f is (1+det(J _f )) times the standard volume form on Euclidean space, is exactly the differential-geometrically natural volume form on the graph of f. The fourth part of the paper shows how the same volume form also makes the IT objective functions symmetric, positive semi-definite, invariant, and unbiased. The fifth part of the paper introduces a method for removing asymmetry in numerical computations and presents results of numerical experiments. The new objective functions and numerical method are tested on a coronal slice of a 3-D MRI brain image. Numerical experiments show that, even in the presence of noise, the new volume form and numerical techniques reduces asymmetry practically down to machine precision without compromising registration accuracy.

Estimation of spatially enhanced soil moisture combining remote sensing and artificial intelligence approaches

The main objective of this study is to combine remote-sensing and artificial intelligence (AI) approaches to estimate surface soil moisture (SM) at 100 m spatial and daily temporal resolution. The two main variables used in the Triangle method, that is, land-surface temperature (LST) and vegetation cover, were downscaled and calculated at 100 m spatial resolution. LSTs were downscaled applying the Wavelet-Artificial Intelligence Fusion Approach (WAIFA) on Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat imageries. Vegetation fractions were also estimated at 100 m spatial resolution using linear spectral un-mixing and Wavelet–AI models. Vegetation indices (VIs) were replaced with the vegetation fractions obtained from sub-pixel classification in the T_s–VI triangle space. The downscaled data were then used for calculating the evaporative fraction (EF), temperature-vegetation-dryness index (TVDI), vegetation temperature condition index (VTCI), and temperature-vegetation index (TVX) at 100 m spatial resolution. Thereafter, surface SM modelling was performed using a combination of Particle Swarm Optimization with Adaptive Neuro Fuzzy Inference System (PSO-ANFIS) and Support Vector Regression (PSO-SVR) modelling approaches. Results showed that the best input data set to estimate SM includes EF, TVDI, T_s, F_vegetation, F_soil, temperature (T), precipitation at time t (P_t, P_{t – 1}, P_{t – 2}), and irrigation (I). It was also confirmed that PSO-SVR outperformed the PSO-ANFIS modelling approach and could estimate SM with a coefficient of determination (R²) of 0.93 and a root mean square error (RMSE) of 1.29 at 100 spatial resolution. Range of error was limited between ?2.64% and 2.8%. It was also shown that the method proposed by Tang et al., (2010) improved the final SM estimations.     

Estimation and distribution of near-surface meteorological elements over complex terrains: a case study in the Tibetan areas of West Sichuan Province,China

ABSTRACT

Meteorological elements are important for various fields related to human activities, including scientific research. Using the Tibetan Areas of West Sichuan Province (TAOWS) as an example, this study examined the estimation methods for near-surface air temperature (T_a), vapour pressure deficit (VPD), and atmospheric pressure (P) and their distribution characteristics in areas with complex terrains and sparse stations. An improved satellite-based approach, combining an artificial neural network and inverse distance weighting (ANN-IDW), is proposed for estimating T_a and VPD with high-accuracy under all weather conditions from Moderate Resolution Imaging Spectroradiometer (MODIS) data. The data of 41 meteorological stations in TAOWS and its adjacent areas were used for the training and validation of the ANN-IDW. For T_a and VPD, the mean absolute errors (MAEs) of the ANN-IDW are 1.45°C to 2.15°C and 0.54 hPa to 0.87 hPa, respectively. Also, the detailed features of the distribution of the estimated T_a and VPD are prominent and closely related to the terrain. The accuracy of the method was also verified indirectly. In addition, the improved method based on the existing method was applied for estimating P. The results confirm that (1) the ANN-IDW is suitable for estimating T_a and VPD in areas with complex terrain and sparse stations under all weather conditions; (2) the improved method is more suitable for estimating P at high-elevation. Moreover, the distribution characteristics of meteorological elements in TAOWS were also analysed. These elements influence agricultural production and animal husbandry and have a high application value. The results further show that topography is the most important factor affecting the spatial distribution and complexity of meteorological elements over complex terrains, but the degree of influence of topography varies greatly across different seasons.     

Comonoids in chu: a large cartesian closed sibling of topological spaces

Com_K may be defined as the (cartesian closed) category of comonoids in chu_K, or equivalently as dictionaries D for which any crossword over D has its main diagonal in D. Com₂ resembles Top, ordinary topological spaces. Common to both are the Alexandroff posets and the Scott DCPOs, while the topological space and the dual DCPO {−∞ < … < −2 < −1 < 0} jointly witness the incomparability of Com₂ and Top. Such comonoids support a notion of bitopology admitting limits simultaneously for convergence and divergence. We raise the questions of whether a comonoid in chu₂ can be fully specified in terms of its specialization order and omitted cuts, and which cuts are optional. These questions have been actively pursued for four weeks as of this writing on the theory-edge mailing list in response to Puzzle 1.5 starting with http://groups.yahoo.com/group/theory-edge/messages/6957.     

Congruence of Bisimulation in a Non-Deterministic Call-By-Need Lambda Calculus

We present a call-by-need λ-calculus λ_ND with an erratic non-deterministic operator pick and a non-recursive let. A definition of a bisimulation is given, which has to be based on a further calculus named λ_≈, since the naïve bisimulation definition is useless. The main result is that bisimulation in λ_≈ is a congruence and coincides with the contextual equivalence. The proof is a non-trivial extension of Howe's method. This might be a step towards defining useful bisimulation relations and proving them to be congruences in calculi that extend the λ_ND-calculus.     

Structural optimization of a full-text <Emphasis Type="Italic">n</Emphasis>-gram index using relational normalization

As the amount of text data grows explosively, an efficient index structure for large text databases becomes ever important. The n-gram inverted index (simply, the n-gram index) has been widely used in information retrieval or in approximate string matching due to its two major advantages: language-neutral and error-tolerant. Nevertheless, the n-gram index also has drawbacks: the size tends to be very large, and the performance of queries tends to be bad. In this paper, we propose the two-level n-gram inverted index (simply, the n-gram/2L index) that significantly reduces the size and improves the query performance by using the relational normalization theory. We first identify that, in the (full-text) n-gram index, there exists redundancy in the position information caused by a non-trivial multivalued dependency. The proposed index eliminates such redundancy by constructing the index in two levels: the front-end index and the back-end index. We formally prove that this two-level construction is identical to the relational normalization process. We call this process structural optimization of the n-gram index. The n-gram/2L index has excellent properties: (1) it significantly reduces the size and improves the performance compared with the n-gram index with these improvements becoming more marked as the database size gets larger; (2) the query processing time increases only very slightly as the query length gets longer. Experimental results using real databases of 1 GB show that the size of the n-gram/2L index is reduced by up to 1.9–2.4 times and, at the same time, the query performance is improved by up to 13.1 times compared with those of the n-gram index. We also compare the n-gram/2L index with Makinen’s compact suffix array (CSA) (Proc. 11th Annual Symposium on Combinatorial Pattern Matching pp. 305–319, 2000) stored in disk. Experimental results show that the n-gram/2L index outperforms the CSA when the query length is short (i.e., less than 15–20), and the CSA is similar to or better than the n-gram/2L index when the query length is long (i.e., more than 15–20).     

Algorithm for Computing Bernstein–Sato Ideals Associated with a Polynomial Mapping

Let f₁, . . . , f_pbe polynomials in n variables with coefficients in a fieldK. We associate with these polynomials a number of functional equations and related ideals B, B_jand BΣ ofK[ s₁, . . . , s_p] called Bernstein–Sato ideals. Using standard basis techniques, our aim is to present an algorithm for computing generators of B_jand BΣ.     

Representing images of a rotating object with cyclic permutation for view-based pose estimation

In this paper, we propose a novel approach using a cyclic group to model the appearance change in an image sequence of an object rotated about an arbitrary axis (1DOF out-of-plane rotation). In the sequence, an image x_j is followed by an image x_j+1. We represent the relationship between images by a cyclic group as x_j+1=Gx_j, and obtain the matrix G by real block diagonalization. Then, G to the power of a real number is used to represent the image sequence and also for pose estimation. Two estimation methods are proposed and evaluated with real image sequences from the COIL-20, COIL-100, and ALOI datasets, and also compared to the Parametric Eigenspace method. Additionally, we discuss the relationship of the proposed approach to the pixel-wise Discrete Fourier Transform (DFT) and to linear regression, and also outline several extensions.     

Combating I-O bottleneck using prefetching: model,algorithms, and ramifications

Multiple memory models have been proposed to capture the effects of memory hierarchy culminating in the I-O model of Aggarwal and Vitter (Commun. ACM 31(9):1116–1127, [1988]). More than a decade of architectural advancements have led to new features that are not captured in the I-O model—most notably the prefetching capability. We propose a relatively simple Prefetch model that incorporates data prefetching in the traditional I-O models and show how to design optimal algorithms that can attain close to peak memory bandwidth. Unlike (the inverse of) memory latency, the memory bandwidth is much closer to the processing speed, thereby, intelligent use of prefetching can considerably mitigate the I-O bottleneck. For some fundamental problems, our algorithms attain running times approaching that of the idealized random access machines under reasonable assumptions. Our work also explains more precisely the significantly superior performance of the I-O efficient algorithms in systems that support prefetching compared to ones that do not.

Efficient KNN search by linear projection of image clusters

K‐nearest neighbors (KNN) search in a high‐dimensional vector space is an important paradigm for a variety of applications. Despite the continuous efforts in the past years, algorithms to find the exact KNN answer set at high dimensions are outperformed by a linear scan method. In this paper, we propose a technique to find the exact KNN image objects to a given query object. First, the proposed technique clusters the images using a self‐organizing map algorithm and then it projects the found clusters into points in a linear space based on the distances between each cluster and a selected reference point. These projected points are then organized in a simple, compact, and yet fast index structure called array‐index. Unlike most indexes that support KNN search, the array‐index requires a storage space that is linear in the number of projected points. The experiments show that the proposed technique is more efficient and robust to dimensionality as compared to other well‐known techniques because of its simplicity and compactness. © 2011 Wiley Periodicals, Inc.     

Development of assessment criteria for clustering algorithms

In this paper, new measures—called clustering performance measures (CPMs)—for assessing the reliability of a clustering algorithm are proposed. These CPMs are defined using a validation measure, which determines how well the algorithm works with a given set of parameter values, and a repeatability measure, which is used for studying the stability of the clustering solutions and has the ability to estimate the correct number of clusters in a dataset. These proposed CPMs can be used to evaluate clustering algorithms that have a structure bias to certain types of data distribution as well as those that have no structure biases. Additionally, we propose a novel cluster validity index, V _I index, which is able to handle non-spherical clusters. Five clustering algorithms on different types of real-world data and synthetic data are evaluated. The first dataset type refers to a communications signal dataset representing one modulation scheme under a variety of noise conditions, the second represents two breast cancer datasets, while the third type represents different synthetic datasets with arbitrarily shaped clusters. Additionally, comparisons with other methods for estimating the number of clusters indicate the applicability and reliability of the proposed cluster validity V _I index and repeatability measure for correct estimation of the number of clusters.

Multiscale enrichment of a finite volume element method for the stationary Navier–Stokes problem

In this paper, we introduce a finite volume element method for the Navier–Stokes problem. This method is based on the multiscale enrichment and uses the lowest finite element pair P ₁/P ₀. The stability and convergence of the optimal order in H ¹-norm for velocity and L ²-norm for pressure are obtained. Using a dual problem for the Navier–Stokes problem, we establish the convergence of the optimal order in L ²-norm for the velocity.     

RRSi: indexing XML data for proximity twig queries

Twig query pattern matching is a core operation in XML query processing. Indexing XML documents for twig query processing is of fundamental importance to supporting effective information retrieval. In practice, many XML documents on the web are heterogeneous and have their own formats; documents describing relevant information can possess different structures. Therefore some “user-interesting” documents having similar but non-exact structures against a user query are often missed out. In this paper, we propose the RRSi, a novel structural index designed for structure-based query lookup on heterogeneous sources of XML documents supporting proximate query answers. The index avoids the unnecessary processing of structurally irrelevant candidates that might show good content relevance. An optimized version of the index, oRRSi, is also developed to further reduce both space requirements and computational complexity. To our knowledge, these structural indexes are the first to support proximity twig queries on XML documents. The results of our preliminary experiments show that RRSi and oRRSi based query processing significantly outperform previously proposed techniques in XML repositories with structural heterogeneity.

A configurable type hierarchy index for OODB

With respect to the specific requirements of advanced OODB applications, index data structures for type hierarchies in OODBMS have to provide efficient support for multiattribute queries and have to allow index optimization for a particular query profile. We describe the multikey type index and an efficient implementation of this indexing scheme. It meets both requirements: in addition to its multiattribute query capabilities it is designed as a mediator between two standard design alternatives, key-grouping and type-grouping. A prerequisite for the multikey type index is a linearization algorithm which maps type hierarchies to linearly ordered attribute domains in such a way that each subhierarchy is represented by an interval of this domain. The algorithm extends previous results with respect to multiple inheritance. The subsequent evaluation of our proposal focuses on storage space overhead as well as on the number of disk I/O operations needed for query execution. The analytical results for the multikey type index are compared to previously published figures for well-known single-key search structures. The comparison clearly shows the superiority of the multikey type index for a large class of query profiles. Edited by E. Bertino. Received October 7, 1996 / Accepted March 28, 1997     

Hermite interpolation and a new iterative method¶for the computation of the roots¶of non-linear equations

We present a new iterative method, derived from Hermite interpolation, with order of convergence p = 1+ , which requires, at each step, only two function evaluations. The efficiency index of the method is better than those of classical methods, such as the secant method or Newton's method, and those of the recent methods introduced by Costabile et al. [1,2] as well. This method has the best efficiency index in a family of methods derived from Hermite interpolation. Received: September 2002 / Accepted: January 2003 Work supported by the Italian agency MURST.