Local Rank Research Articles

Gray codes over certain run-length sequences for local rank modulation

In the local rank modulation (LRM) scheme, a sliding window produces a sequence of permutations by moving over a sequence of variables. LRM has been presented as a method of storing data in flash memory, which represents a natural generalization of the classical rank modulation scheme. In this paper, we present a study on Gray codes over certain run-length sequences for the $(1,2,n)$-LRM scheme to simulate virtual multilevel flash memory cells while maintaining the advantages of LRM. Unlike previous studies on the LRM scheme, we present Gray codes over certain run-length sequences in the $(1,2,n)$-LRM scheme. This class of Gray codes can overcome the drawback of the many distinct charge levels required in the rank modulation scheme and in certain Gray codes for LRM. Furthermore, we demonstrate that the proposed codes have an asymptotically optimal rate.

Image and Spectrum Image Denoising under the local low Rank Assumption

Image and Spectrum Image Denoising under the local low Rank Assumption

The ‘new’ African customary land tenure. Characteristic, features and policy implications of a new paradigm

Most of the land in sub-Saharan Africa is governed under various forms of customary tenure. Over the past three decades a quiet paradigm shift has been taking place transforming the way such landl is governed. Driven in part by adaptations to changing context but also accelerated by neo-liberal reforms, this shift has created a ‘new’ customary tenure in sub-Saharan Africa. This paper reviews some of the evidence and analyses the ways in which this neo-liberalisation of customary tenure has been transforming relations of production and how land is governed in sub-Saharan Africa. It identifies how core neo-liberalisation processes such as privatisation of rights, commoditisation, de-regulation; re-regulation and flanking have led to a formal reconfiguration of the way people relate to land. It presents a characterisation of the ‘new’-African customary tenure before sketching out evidence of outcomes associated with neo-liberalisation of customary tenure. The paper identifies five outcomes marking out the new customary tenure’s legacy. These are: creating new class dynamics (those with registered rights and those without), altered institutional power relations (extending statutory governance), local rank order change (replacing the traditional ‘big men’ of rural Africa with ‘new’ big shots), miniaturisation of smallholder farming and the growth in medium scale farms, growing inequality and potential social differentiation.

Query-dependent learning to rank for cross-lingual information retrieval

Learning to rank (LTR), as a machine learning technique for ranking tasks, has become one of the most popular research topics in the area of information retrieval (IR). Cross-lingual information retrieval (CLIR), in which the language of the query is different from the language of the documents, is one of the important IR tasks that can potentially benefit from LTR. Our focus in this paper is the use of LTR for CLIR. To rank the documents in the target language in response to the query in the source language, we propose a local query-dependent approach based on LTR for CLIR, which is called LQ-DLTR for CLIR. The core idea of LQ-DLTR for CLIR is the use of the local characteristics of similar queries to construct the LTR model, instead of using a single global ranking model for all queries. Since the query and the documents are in different languages, the traditional features that are used in LTR cannot be used directly for CLIR. Thus, defining appropriate features is a major step in the use of LTR for CLIR. In this paper, three categories of cross-lingual features are defined: query–document features, document features, and query features. To define the cross-lingual features, translation resources are used to fill the gap between the documents and the queries. Then, in LQ-DLTR for CLIR, a neighborhood of similar queries based on cross-lingual query features is used to create a local ranking function by the LTR algorithm for a given query. The LTR algorithm uses two cross-lingual feature sets, namely document features and query–document features, to learn the model. The query features that are used to identify the neighbors are not involved in the learning phase. Experimental results indicate that the CLIR performance improves with the use of cross-lingual features that use several translations and their probabilities to compute the features, compared to the use of monolingual features in traditional LTR, which translate a query according to the best translation and ignore the probabilities. Moreover, experimental results show that LQ-DLTR for CLIR outperforms the baseline information retrieval methods and other LTR ranking models in terms of the MAP and NDCG measures.

Risk-based structural integrity management for offshore jacket platforms

This paper presents a method for risk assessment and inspection plan development as part of the risk-based structural integrity management of offshore jacket platforms. The method provides a global risk assessment for the whole platform's structure and local risk assessment for the platform's structural components (e.g. tubular joints). The global risk assessment uses semi-quantitative or quantitative approaches depending on the available platform's data. The semi-quantitative method is used either at a high level to perform relative risk ranking of platforms in a fleet in order to identify the platforms most at risk and which require more inspection focus or a detailed risk analysis; or at the unit level to define inspection interval and general inspection requirements. The quantitative method involves either structural analysis results (e.g. reserve strength ratio) with a dedicated metocean hazard curve or structural reliability method; and it is used at the unit level only to define inspection interval and inspection requirements. The local risk assessment uses also semi-quantitative or quantitative approach. The semi-quantitative method is used to provide local risk ranking of the structural components of a platform, which allows, if required, local inspections' scope to be defined. The quantitative method involves a probabilistic fatigue method to define inspection plans for selected tubular joints subjected to fatigue and the failures of which are critical for the overall platform structure. The inspection strategy and program, developed by the method presented in this paper, are focused on the routine underwater inspections and are based on the recommended practice of the American Petroleum Institute for the structural integrity management of fixed offshore platforms. An example of application of the method is set out by showing the results of a project carried out by Bureau Veritas.

Slow entropy for some smooth flows on surfaces

We study slow entropy in some classes of smooth mixing flows on surfaces. The flows we study can be represented as special flows over irrational rotations and under roof functions which are C2 everywhere except one point (singularity). If the singularity is logarithmic asymmetric (Arnol’d flows), we show that in the scale an(t) = n(log n)t slow entropy equals 1 (the speed of orbit growth is n log n) for a.e. irrational α. If the singularity is of power type (x−γ, γ ∈ (0, 1)) (Kochergin flows), we show that in the scale an(t) = nt slow entropy equals 1 + γ for a.e. α. We show moreover that for local rank one flows, slow entropy equals 0 in the n(log n)t scale and is at most 1 for scale nt. As a consequence we get that a.e. Arnol’d and a.e Kochergin flow is never of local rank one.

Is predatory publishing a real threat? Evidence from a large database study

Using a database of potential, possible, or probable predatory scholarly open-access journals, the objective of this research is to study the penetration of predatory publications in the Brazilian academic system and the profile of authors in a cross-section empirical study. Based on a massive amount of publications from Brazilian researchers of all disciplines during the 2000–2015 period, we were able to analyze the extent of predatory publications using an econometric modeling. Descriptive statistics indicate that predatory publications represent a small overall proportion, but grew exponentially in the last 5 years. Departing from prior studies, our analysis shows that experienced researchers with a high number of non-indexed publications and PhD obtained locally are more likely to publish in predatory journals. Further analysis shows that once a journal regarded as predatory is listed in the local ranking system, the Qualis, it starts to receive more publications than non-predatory ones.

On geometric classification of 5d SCFTs

We formulate geometric conditions necessary for engineering 5d superconformal field theories (SCFTs) via M-theory compactification on a local Calabi-Yau 3-fold. Extending the classification of the rank 1 cases, which are realized geometrically as shrinking del Pezzo surfaces embedded in a 3-fold, we propose an exhaustive classification of local 3-folds engineering rank 2 SCFTs in 5d. This systematic classification confirms that all rank 2 SCFTs predicted using gauge theoretic arguments can be realized as consistent theories, with the exception of one family which is shown to be non-perturbatively inconsistent and thereby ruled out by geometric considerations. We find that all rank 2 SCFTs descend from 6d (1,0) SCFTs compactified on a circle possibly twisted with an automorphism together with holonomies for global symmetries around the Kaluza-Klein circle. These results support our conjecture that every 5d SCFT can be obtained from the circle compactification of some parent 6d (1,0) SCFT.

A system approach to decision support on basis of hierarchical and network models

A methodology and a system approach to decision support based on hierarchical and network models are proposed, which include methods for estimating and improving the consistency of pairwise comparison matrices (PCM), calculating fuzzy local weights for model elements based on fuzzy PCM, calculating confidence intervals for local weights, finding aggregated weights and aggregated belief functions for model elements, estimating the sensitivity of the results, tools for analyzing the effectiveness of the methods and an expert evaluation modeling system. A decision support system is built on basis of the proposed methodology. The proposed methodology makes it possible to increase the reliability of solutions of practical weakly structured decision-making problems by using more efficient methods at each of the stages of solving the problem. Reliability of results of application of the methodology while solving a practical decision-making problem can be assessed by means of sensitivity analysis using the stability indices of the computed local and global rankings of the decision alternatives.

Using a local low rank plus sparse reconstruction to accelerate dynamic hyperpolarized 13C imaging using the bSSFP sequence

Acceleration of dynamic 2D (T2 Mapping) and 3D hyperpolarized 13C MRI acquisitions using the balanced steady-state free precession sequence was achieved with a specialized reconstruction method, based on the combination of low rank plus sparse and local low rank reconstructions. Methods were validated using both retrospectively and prospectively undersampled in vivo data from normal rats and tumor-bearing mice. Four-fold acceleration of 1–2 mm isotropic 3D dynamic acquisitions with 2–5 s temporal resolution and two-fold acceleration of 0.25–1 mm2 2D dynamic acquisitions was achieved. This enabled visualization of the biodistribution of [2-13C]pyruvate, [1-13C]lactate, [13C, 15N2]urea, and HP001 within heart, kidneys, vasculature, and tumor, as well as calculation of high resolution T2 maps.

FORMATION OF ENVIRONMENTAL COMPETENCY OF STUDENTS OF BIOLOGICAL SPECIALTIES IN THE PROCESS OF POLISH PRACTICE

Organizational-process possibilities of the educational field practice for the purpose of ecological competence forming for the students of biological specialties have been presented in the article. Basic factors which complicate students ecological competence forming, fundamental directions of its formation in the process of organization and realization field practice have been underlined in the article.The content of field practice requires additional information on the methods of environmental monitoring in the environment and on the domestic issues. Particularly relevant is the saturation of field practices with the tasks of applied local history and those that affect the spheres of domestic activities and human impact on the environment. Methods of educational impact on students are also needed. Among the generally positive conditions for the formation of environmental competence of students (the presence of ecological content in the discipline, the possibility of self-realization during seminars and laboratory classes, the practical application of acquired knowledge in field practice), there are factors that impede the formation of this quality. Among them is the lack of content of the environmental issues of the local rank and the practical absence of information relating to the domestic sphere of the person's activities (complicates the decision-making process and responsibility for the state of the surrounding environment), the prevailing use of educational and educational methods that contradict the norms of environmental behavior (make it impossible to form a value the attitude towards nature, environmental motivation and related activities, suppress the readiness to preserve nature and the responsibility for it with en).

Research assessment by percentile-based double rank analysis

In the double rank analysis of research publications, the local rank position of a country or institution publication is expressed as a function of the world rank position. Excluding some highly or lowly cited publications, the double rank plot fits well with a power law, which can be explained because citations for local and world publications follow lognormal distributions. We report here that the distribution of the number of country or institution publications in world percentiles is a double rank distribution that can be fitted to a power law. Only the data points in high percentiles deviate from it when the local and world $\mu$ parameters of the lognormal distributions are very different. The likelihood of publishing very highly cited papers can be calculated from the power law that can be fitted either to the upper tail of the citation distribution or to the percentile-based double rank distribution. The great advantage of the latter method is that it has universal application, because it is based on all publications and not just on highly cited publications. Furthermore, this method extends the application of the well-established percentile approach to very low percentiles where breakthroughs are reported but paper counts cannot be performed.

Local low rank denoising for enhanced atomic resolution imaging

Atomic resolution imaging and spectroscopy suffers from inherently low signal to noise ratios often prohibiting the interpretation of single pixels or spectra. We introduce local low rank (LLR) denoising as tool for efficient noise removal in scanning transmission electron microscopy (STEM) images and electron energy-loss (EEL) spectrum images. LLR denoising utilizes tensor decomposition techniques, in particular the multilinear singular value decomposition (MLSVD), to achieve a denoising in a general setting largely independent of the signal features and data dimension, by assuming that the signal of interest is of low rank in segments of appropriately chosen size. When applied to STEM images of graphene, LLR denoising suppresses statistical noise while retaining fine image features such as scan row-wise distortions, possibly related to rippling of the graphene sheet and consequent motion of atoms. When applied to EEL spectra, LLR denoising reveals fine structures distinguishing different lattice sites in the spinel system CoFe2O4.

Iris Template Protection Based on Local Ranking

Biometrics have been widely studied in recent years, and they are increasingly employed in real-world applications. Meanwhile, a number of potential threats to the privacy of biometric data arise. Iris template protection demands that the privacy of iris data should be protected when performing iris recognition. According to the international standard ISO/IEC 24745, iris template protection should satisfy the irreversibility, revocability, and unlinkability. However, existing works about iris template protection demonstrate that it is difficult to satisfy the three privacy requirements simultaneously while supporting effective iris recognition. In this paper, we propose an iris template protection method based on local ranking. Specifically, the iris data are first XORed (Exclusive OR operation) with an application-specific string; next, we divide the results into blocks and then partition the blocks into groups. The blocks in each group are ranked according to their decimal values, and original blocks are transformed to their rank values for storage. We also extend the basic method to support the shifting strategy and masking strategy, which are two important strategies for iris recognition. We demonstrate that the proposed method satisfies the irreversibility, revocability, and unlinkability. Experimental results on typical iris datasets (i.e., CASIA-IrisV3-Interval, CASIA-IrisV4-Lamp, UBIRIS-V1-S1, and MMU-V1) show that the proposed method could maintain the recognition performance while protecting the privacy of iris data.

Local government climate change mitigation and adaptation ranking assessment

Climate change awareness in local areas is critical, and this study assessed levels of mitigation and adaptation of local government areas (LGAs), across the rural/urban State of Tasmania. Fourteen indicators were developed in the sectors of energy, transport, awareness, and physical carbon sinks, and allocated quantitative parameters for ranking. Results were mapped using geographical information systems software. Higher energy results occurred on the two large northern islands both with solar and wind generation facilities, and around some cities with energy efficient street lighting systems. Highest transport scores occurred in the remote west, and around most cities, but mostly not in agricultural areas. Higher awareness levels and overall scores were found around city areas. Higher physical scores resulted from community tree plantings and carbon sequestering vegetation. This study shows how geographic trend mapping can improve understanding of spatial differences in climate change mitigation and adaptation, to improve prioritised allocation of assistance policy.

Local government climate change mitigation and adaptation ranking assessment

Local government climate change mitigation and adaptation ranking assessment

$G$-Weights and $p$-Local Rank

Let $k$ be field of characteristic $p$, andlet $G$ be any finite group with splitting field $k$. Assume that $B$ is a $p$-block of $G$.In this paper, we introduce the notion of radical $B$-chain $C_{B}$, and we show that the $p$-local rank of $B$ is equals the length of $C_{B}$. Moreover, we prove that the vertex of a simple $kG$-module $S$ is radical if and only if it has the same vertex of the unique direct summand, up to isomorphism, of the Sylow permutationmodule whose radical quotient is isomorphic to $S$. Finally, we prove the vertices of certain direct summands of the Sylow permutation module are bounds for the vertices of simple $kG$-modules.

Publisher's note

Abstract This paper presents a method for risk assessment and inspection plan development as part of the risk-based structural integrity management of offshore jacket platforms. The method provides a global risk assessment for the whole platform's structure and local risk assessment for the platform's structural components (e.g. tubular joints). The global risk assessment uses semi-quantitative or quantitative approaches depending on the available platform's data. The semi-quantitative method is used either at a high level to perform relative risk ranking of platforms in a fleet in order to identify the platforms most at risk and which require more inspection focus or a detailed risk analysis; or at the unit level to define inspection interval and general inspection requirements. The quantitative method involves either structural analysis results (e.g. reserve strength ratio) with a dedicated metocean hazard curve or structural reliability method; and it is used at the unit level only to define inspection interval and inspection requirements. The local risk assessment uses also semi-quantitative or quantitative approach. The semi-quantitative method is used to provide local risk ranking of the structural components of a platform, which allows, if required, local inspections' scope to be defined. The quantitative method involves a probabilistic fatigue method to define inspection plans for selected tubular joints subjected to fatigue and the failures of which are critical for the overall platform structure. The inspection strategy and program, developed by the method presented in this paper, are focused on the routine underwater inspections and are based on the recommended practice of the American Petroleum Institute for the structural integrity management of fixed offshore platforms. An example of application of the method is set out by showing the results of a project carried out by Bureau Veritas.

Is Predatory Publishing a Real Threat? Evidence from a Large Database Study

Using a database of potential, possible, or probable predatory scholarly open-access journals, the objective of this research is to study the penetration of predatory publications in the Brazilian academic system and the profile of authors in a cross-section empirical study. Based on a massive amount of publications from Brazilian researchers of all disciplines during the 2000 to 2015 period, we were able to analyze the extent of predatory publications using an econometric modeling. Descriptive statistics indicate that predatory publications represent a small overall proportion, but grew exponentially in the last 5 years. Departing from prior studies, our analysis shows that experienced researchers with a high number of non-indexed publications and PhD obtained locally are more likely to publish in predatory journals. Further analysis shows that once a journal regarded as predatory is listed in the local ranking system, the Qualis, it starts to receive more publications than non-predatory ones.

Robust first quantization matrix estimation based on filtering of recompression artifacts for non-aligned double compressed JPEG images

This paper presents a novel method for first quantization matrix estimation for non-aligned double JPEG compressed images. The non-aligned double JPEG scenario poses several challenges in the form of recompression artifacts which needs to be handled effectively in order to arrive at accurate first quantization estimate. One such recompression artifact which is prominent in the non-aligned scenario is the blocking artifacts arising due to the misalignment of the DCT grids in the successive compression cycles. The proposed method investigates the impact of the blocking artifacts induced errors on the DCT histogram and counters these errors via a novel DCT histogram filtering strategy. In addition, the residual noise which is also a recompression artifact is countered utilizing the local rank transform which adaptively filters the residual noise effects. The filtered histograms are compared with a synthetically created ideal second quantization matrix to estimate the degree of similarity between the two cases. Utilizing the maximum degree of similarity, the selection of first quantization value is performed. Experimental analysis utilizing several non-aligned double compressed JPEG images taken from UCID and RAISE datasets with Quality Factor (QF) of second compression being greater than the first compression (QF2>QF1) along with the comparative analysis with one of the state-of-the-art method shows accurate estimation of the first quantization values for the proposed method. The proposed method finds its application in image forensics as well as in steganalysis.