Towards an automatic extraction of synonyms for Quranic Arabic WordNet

In this paper, we developed an automatic extraction model of synonyms, which is used to construct our Quranic Arabic WordNet (QAWN) that depends on traditional Arabic dictionaries. In this work, we rely on three resources. First, the Boundary Annotated Quran Corpus that contains Quran words, Part-of-Speech, root and other related information. Second, the lexicon resources that was used to collect a set of derived words for Quranic words. Third, traditional Arabic dictionaries, which were used to extract the meaning of words with distinction of different senses. The objective of this work is to link the Quranic words of similar meanings in order to generate synonym sets (synsets). To accomplish that, we used term frequency and inverse document frequency in vector space model, and we then computed cosine similarities between Quranic words based on textual definitions that are extracted from traditional Arabic dictionaries. Words of highest similarity were grouped together to form a synset. Our QAWN consists of 6918 synsets that were constructed from about 8400 unique word senses, on average of 5 senses for each word. Based on our experimental evaluation, the average recall of the baseline system was 7.01 %, whereas the average recall of the QAWN was 34.13 % which improved the recall of semantic search for Quran concepts by 27 %.     

Multi-robot repeated area coverage

We address the problem of repeated coverage of a target area, of any polygonal shape, by a team of robots having a limited visual range. Three distributed Cluster-based algorithms, and a method called Cyclic Coverage are introduced for the problem. The goal is to evaluate the performance of the repeated coverage algorithms under the effects of the variables: Environment Representation, and the Robots’ Visual Range. A comprehensive set of performance metrics are considered, including the distance the robots travel, the frequency of visiting points in the target area, and the degree of balance in workload distribution among the robots. The Cyclic Coverage approach, used as a benchmark to compare the algorithms, produces optimal or near-optimal solutions for the single robot case under some criteria. The results can be used as a framework for choosing an appropriate combination of repeated coverage algorithm, environment representation, and the robots’ visual range based on the particular scenario and the metric to be optimized.     

Semantic similarity based approach for reducing Arabic texts dimensionality

An efficient method is introduced to represent large Arabic texts in comparatively smaller size without losing significant information. The proposed method uses the distributional semantics to build the word-context matrix representing the distribution of words across contexts and to transform the text into a vector space model (VSM) representation based on word semantic similarity. The linguistic features of the Arabic language, in addition to the semantic information extracted from different lexical-semantic resources such as Arabic WordNet and named entities’ gazetteers are used to improve the text representation and to create word clusters of similar and related words. Distributional similarity measures have been used to capture the words’ semantic similarity and to create clusters of similar words. The conducted experiments have shown that the proposed method significantly reduces the size of text representation by about 27 % compared with the stem-based VSM and by about 50 % compared with the traditional bag-of-words model. Their results have shown that the amount of dimension reduction depends on the size and shape of the windows of analysis as well as on the content of the text.     

A frame-based approach for capturing semantics from Arabic text for text-to-sign language MT

This paper describes the design and implementation of a computational model for Arabic natural language semantics, a semantic parser for capturing the deep semantic representation of Arabic text. The parser represents a major part of an Interlingua-based machine translation system for translating Arabic text into Sign Language. The parser follows a frame-based analysis to capture the overall meaning of Arabic text into a formal representation suitable for NLP applications that need for deep semantics representation, such as language generation and machine translation. We will show the representational power of this theory for the semantic analysis of texts in Arabic, a language which differs substantially from English in several ways. We will also show that the integration of WordNet and FrameNet in a single unified knowledge resource can improve disambiguation accuracy. Furthermore, we will propose a rule based algorithm to generate an equivalent Arabic FrameNet, using a lexical resource alignment of FrameNet1.3 LUs and WordNet3.0 synsets for English Language. A pilot study of motion and location verbs was carried out in order to test our system. Our corpus is made up of more than 2000 Arabic sentences in the domain of motion events collected from Algerian first level educational Arabic books and other relevant Arabic corpora.     

An adaptive Huber method for weakly singular second kind Volterra integral equations with non-linear dependencies between unknowns and their integrals

Numerical methods for weakly singular Volterra integral equations with non-linear dependencies between unknowns and their integrals, are almost non-existent in the literature. In the present work an adaptive Huber method for such equations is proposed, by extending the method previously formulated for the first kind Abel equations. The method is tested on example integral equations involving integrals with kernels K(t, τ) = (t ? τ)^?1/2, K(t, τ) = exp[?λ(t ? τ)](t ? τ)^?1/2 (where λ > 0), and K(t, τ) = 1. By controlling estimated local discretisation errors, the integral equation can be solved adaptively on a discrete grid of nodes in the independent variable domain, in a step-by-step fashion. The practical accuracy order is close to 2. The accuracy can be varied by varying the prescribed local error tolerance parameter tol, although the actual errors tend to be larger than tol. Approximations to off-nodal solution values can also be computed, with a comparable accuracy. The method appears numerically stable when partial derivatives, of the non-linear function representing the equation, with respect to the unknown and its integral(s), are of the same sign. The stability of the method in the opposite case may be debated.     

Using part–whole relations for automatic deduction of compound-internal relations in GermaNet

This paper provides a deduction-based approach for automatically classifying compound-internal relations in GermaNet, the German version of the Princeton WordNet for English. More specifically, meronymic relations between simplex and compound nouns provide the necessary input to the deduction patterns that involve different types of compound-internal relations. The scope of these deductions extends to all four meronymic relations modeled in version 6.0 of GermaNet: component, member, substance, and portion. This deduction-based approach provides an effective method for automatically enriching the set of semantic relations included in GermaNet.     

The use of autonomous vehicles for spatially measuring mean velocity profiles in rivers and estuaries

Autonomous vehicles (AVs) are commonly used in oceanic and more recently estuarine and riverine environments because they are small, versatile, efficient, moving platforms equipped with a suite of instruments for measuring environmental conditions. However, moving vessel observations, particularly those associated with Acoustic Doppler Current Profiler (ADCP) measurements, can be problematic owing to instrument noise, flow fluctuations, and spatial variability. A range of ADCPs manufactured by different companies were integrated on to an Unmanned Surface Vehicle (USV), an Unmanned Underwater Vehicle (UUV), and some additional stationary platforms and were deployed in a number of natural riverine and estuarine environments to evaluate the quality of the velocity profile over the depth, minimum averaging time interval requirements, and AV mission planning considerations. Measurements were obtained at fixed locations to eliminate any spatial variations in the mean flow characteristics. The USV has the unique capability to station-keep to within 1 m owing to its dual-propeller design, providing the best setup for spatially mapping velocity profiles. Single-propeller UUVs can perform a quasi-station-keeping (< 10 m) operation, but are designed for traveling underwater at speeds > 1 m/s. An appropriate averaging window, T _*, was determined using the Kalman Algorithm with a Kalman gain equal to 1%. T _* was found to be independent of depth, flow velocity, and environment. There was no correlation (R ² = 0.18) for T _* between flow magnitude and direction. Results from all measurements had a similar T _* of approximately 3 min. Based on this, an averaging window of 4 min is conservatively suggested to obtain a statistically confident measure of the mean velocity profile.     

A new matrix test for randomness

Let ${{\mathcal S}}$ be one of the two multiplicative semigroups: M × M Boolean matrices, or the semigroup of M × M matrices over the field GF(2). Then for any matrix ${A\in {\mathcal S}}$ there exist two unique smallest numbers, namely the index and period k, d, such that A ^k  = A ^k+d . This fact allows us to form a new statistical test for randomness which we call the Semigroup Matrix Test. In this paper, we present details and results of our experiments for this test. We use Boolean matrices for M = 2, . . . , 5, and matrices over GF(2) of the size M = 2, . . . , 6. We also compare the results with the results obtained by the well-known Binary Matrix Rank Test.     

Identifying local anthropogenic CO2 emissions with satellite retrievals: a case study in South Korea

We used multiyear Greenhouse Gases Observing Satellite (GOSAT) dry air, column-integrated CO₂ (XCO₂) retrievals (2010–2013) to evaluate urban and local-scale CO₂ emissions over East Asia and examined whether GOSAT XCO₂ captures the impact of strong local CO₂ emissions over South Korea, an East Asian downwind region with high atmospheric aerosol loading and strong summer monsoons. We chose a region in western Mongolia (upwind region) as the XCO₂ background, and estimated XCO₂ enhancements in South Korea to gauge local and regional emissions. We found that the cold season (November–February) was better suited for estimating XCO₂ enhancements of local emissions due to the summer monsoon and stronger transboundary impacts in other seasons. In particular, we focused on three local GOSAT XCO₂ footprints (about 10.5 km in diameter) in South Korea: the Seoul Metropolitan Area (SMA), the Gwangyang Steelworks and Hadong power plants (GYG), and the Samcheonpo power plants (SCH). The range of XCO₂ enhancement was 7.3–10.7 ppm (14.1–21.3 mg m^?3 in standard temperature and pressure (STP)). By estimating other important contributions to XCO₂ enhancements such as the XCO₂ latitudinal gradients and Chinese fossil fuel combustions, we estimated the net enhancements caused mainly by local CO₂ emissions in the range of 4.2–7.6 ppm (8.1–14.7 mg m^?3 in STP) These high enhancements imply that large point source contributions are an important factor in determining these enhancements, even if contributions are also made by broader-scale emissions. Additionally, differences in net XCO₂ enhancements and trends between GYG (+ 4.2 ppm (+ 8.2 mg m^?3 in STP), – 0.2 ppm year^?1 (–0.4 mg m^?3 year^?1 in STP)) and SCH (+ 7.6 ppm (+ 14.9 mg m^?3 in STP), + 1.3 ppm year^?1 (+ 2.6 mg· m^?3 year^?1 in STP)) indicate that these closely located footprints (approximately 26 km apart) are separable. These results will be useful in evaluating and reducing uncertainties in regional and local anthropogenic greenhouse gas (GHG) emissions over East Asia.     

A variant of Wiener’s attack on RSA

Wiener’s attack is a well-known polynomial-time attack on a RSA cryptosystem with small secret decryption exponent d, which works if d < n ^0.25, where n = pq is the modulus of the cryptosystem. Namely, in that case, d is the denominator of some convergent p _m /q _m of the continued fraction expansion of e/n, and therefore d can be computed efficiently from the public key (n, e). There are several extensions of Wiener’s attack that allow the RSA cryptosystem to be broken when d is a few bits longer than n ^0.25. They all have the run-time complexity (at least) O(D ²), where d = Dn ^0.25. Here we propose a new variant of Wiener’s attack, which uses results on Diophantine approximations of the form |α ? p/q| <  c/q ², and “meet-in-the-middle” variant for testing the candidates (of the form rq _m+1 +  sq _m ) for the secret exponent. This decreases the run-time complexity of the attack to O(D log D) (with the space complexity O(D)).     

Mobile touchscreen user interfaces: bridging the gap between motor-impaired and able-bodied users

Touchscreen mobile devices are highly customizable, allowing designers to create inclusive user interfaces that are accessible to a broader audience. However, the knowledge to provide this new generation of user interfaces is yet to be uncovered. The goal was to thoroughly study mobile touchscreen interfaces and provide guidelines for informed design. The paper presents an evaluation performed with 15 tetraplegic and 18 able-bodied users that allowed to identify their main similarities and differences within a set of interaction techniques (Tapping, Crossing, and Directional Gesturing) and parameterizations. Results show that Tapping and Crossing are the most similar and easy to use techniques for both motor-impaired and able-bodied users. Regarding Tapping, error rates start to converge at 12 mm, showing to be a good compromise for target size. As for Crossing, it offered a similar level of accuracy; however, larger targets (17 mm) are significantly easier to cross for motor-impaired users. Directional Gesturing was the least inclusive technique. Regarding position, edges showed to be troublesome. For instance, they have shown to increase Tapping precision for disabled users, while decreasing able-bodied users’ accuracy when targets are too small (7 mm). It is argued that despite the expected error rate disparity, there are clear resemblances between user groups, thus enabling the development of inclusive touch interfaces. Tapping, a traditional interaction technique, was among the most effective for both target populations, along with Crossing. The main difference concerns Directional Gesturing that in spite of its unconstrained nature shows to be inaccurate for motor-impaired users.     

How do environmental characteristics at intersections change in their relevance for drivers before entering an intersection: analysis of drivers’ gaze and driving behavior in a driving simulator study

Accident studies in Germany found that in about 90 % of intersection accidents, failure to acquire the relevant information of the driving situation was the main reason for drivers’ errors (Vollrath et al. in Ableitung von Anforderungen an Fahrerassistenzsysteme aus Sicht der Verkehrssicherheit. Wirtschaftsverlag NW, Bremerhaven, 2006). Studies of bicycle–car accidents assume that improper attention allocation strategies and unjustified expectations by drivers are important for this kind of error (Räsänen and Summala in Accid Anal Prev 30:657–666, 1998). Aim of the study was to examine the psychological processes of drivers’ attention allocation and driving behavior in different intersection situations varied by two environmental characteristics. A give way T-intersection was varied by (1) low and high traffic density of oncoming cars from the left and (2) number of task-relevant information areas (in addition to the oncoming cars from the left with or without pedestrians on the right). It was examined how these environmental characteristics change in their relevance for drivers while entering the intersections. The analysis was conducted in three intersection epochs (Approaching, Waiting, Accelerating). A total of 40 subjects (26 male, 14 female), ranged in age from 19 to 55 years (M = 31.0 years), participated in the study. The results showed that drivers’ attention allocation (e.g., mean gaze duration) and driving behavior (e.g., waiting time) systematically depends on these environmental characteristics which require different actions of the driver and change in their relevance when entering an intersection. The results support the idea of attention allocation strategies by drivers which are specific for certain driving situations. These findings can support approaches of driver modeling at intersections.     

A linear-time algorithm for finding Hamiltonian (<Emphasis Type="Italic">s</Emphasis>, <Emphasis Type="Italic">t</Emphasis>)-paths in odd-sized rectangular grid graphs with a rectangular hole

A grid graph \(G_{\mathrm{g}}\) is a finite vertex-induced subgraph of the two-dimensional integer grid \(G^\infty \). A rectangular grid graph R(m, n) is a grid graph with horizontal size m and vertical size n. A rectangular grid graph with a rectangular hole is a rectangular grid graph R(m, n) such that a rectangular grid subgraph R(k, l) is removed from it. The Hamiltonian path problem for general grid graphs is NP-complete. In this paper, we give necessary conditions for the existence of a Hamiltonian path between two given vertices in an odd-sized rectangular grid graph with a rectangular hole. In addition, we show that how such paths can be computed in linear time.     

Intercomparison of satellite and ground-based measurements of ozone,NO2, HF,and HCl near Saint Petersburg,Russia

Regular intercomparison of different observing systems is a part of their testing and validation protocol, which gives the estimates of real measurement errors. The main objective of our study is the comparison of satellite and ground-based measurements of atmospheric composition near Saint Petersburg, Russia. Since early 2009, high-resolution Fourier Transform Infrared (FTIR) solar absorption spectra have been recorded at Peterhof station (59.82° N, 29.88° E), located in the suburbs of Saint Petersburg. We derived column amounts of O₃, HCl, HF, and NO₂ from these spectra using the retrieval codes SFIT2 and PROFFIT. We compared the data retrieved from Bruker 125 HR FTIR measurements with coincident satellite observations of the Microwave Limb Sounding (MLS), Ozone Monitoring Instrument (OMI), Fourier Transform Spectrometer from Atmospheric Chemistry Experiment (ACE-FTS), Global Ozone Monitoring Experiment (GOME and GOME-2), and Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instruments. The relative differences in ozone columns of FTIR from OMI-TOMS amount within (+3.4 ± 2.9)%, from GOME-2 are (+2.2 ± 3.0)%. The comparison of FTIR and MLS measurements of stratospheric ozone columns gives no mean and 5% of the RMS differences. Measurements of NO₂ columns agree with the mean difference of +9% and the RMS differences within 14–16% for FTIR vs. GOME-2, SCIAMACHY, and OMI. FTIR vs. GOME comparison gives (+6 ± 31)%. HCl columns comparison for FTIR vs. MLS shows ?4.5% in the mean and 12% in the RMS differences. FTIR vs. ACE-FTS comparison (nine cases) gives ?8% and 10% for the mean and the RMS relative differences, respectively. Comparison of HF columns shows (?12 ± 6)% and (?12 ± 11)% for FTIR vs. ACE data v.2.2 and v.3.0, respectively. These figures show that the Peterhof ground-based FTIR measuring system can be used to support the validation of satellite data in the monitoring of stratospheric gases.     

Wetting considerations in capillary rise and imbibition in closed square tubes and open rectangular cross-section channels

The spontaneous capillary-driven filling of microchannels is important for a wide range of applications. These channels are often rectangular in cross-section, can be closed or open, and horizontal or vertically orientated. In this work, we develop the theory for capillary imbibition and rise in channels of rectangular cross-section, taking into account rigidified and non-rigidified boundary conditions for the liquid–air interfaces and the effects of surface topography assuming Wenzel or Cassie-Baxter states. We provide simple interpolation formulae for the viscous friction associated with flow through rectangular cross-section channels as a function of aspect ratio. We derive a dimensionless cross-over time, T _c, below which the exact numerical solution can be approximated by the Bousanquet solution and above which by the visco-gravitational solution. For capillary rise heights significantly below the equilibrium height, this cross-over time is T _c ≈ (3X _e/2)^2/3 and has an associated dimensionless cross-over rise height X _c ≈ (3X _e/2)^1/3, where X _e = 1/G is the dimensionless equilibrium rise height and G is a dimensionless form of the acceleration due to gravity. We also show from wetting considerations that for rectangular channels, fingers of a wetting liquid can be expected to imbibe in advance of the main meniscus along the corners of the channel walls. We test the theory via capillary rise experiments using polydimethylsiloxane oils of viscosity 96.0, 48.0, 19.2 and 4.8 mPa s within a range of closed square tubes and open rectangular cross-section channels with SU-8 walls. We show that the capillary rise heights can be fitted using the exact numerical solution and that these are similar to fits using the analytical visco-gravitational solution. The viscous friction contribution was found to be slightly higher than predicted by theory assuming a non-rigidified liquid–air boundary, but far below that for a rigidified boundary, which was recently reported for imbibition into horizontally mounted open microchannels. In these experiments we also observed fingers of liquid spreading along the internal edges of the channels in advance of the main body of liquid consistent with wetting expectations. We briefly discuss the implications of these observations for the design of microfluidic systems.     

Towards Optimal and Expressive Kernelization for d-Hitting Set

A sunflower in a hypergraph is a set of hyperedges pairwise intersecting in exactly the same vertex set. Sunflowers are a useful tool in polynomial-time data reduction for problems formalizable as d-Hitting Set, the problem of covering all hyperedges (whose cardinality is bounded from above by a constant d) of a hypergraph by at most k vertices. Additionally, in fault diagnosis, sunflowers yield concise explanations for “highly defective structures”. We provide a linear-time algorithm that, by finding sunflowers, transforms an instance of d-Hitting Set into an equivalent instance comprising at most O(k ^d ) hyperedges and vertices. In terms of parameterized complexity, we show a problem kernel with asymptotically optimal size (unless \(\operatorname {coNP}\subseteq \operatorname {NP/poly}\) ) and provide experimental results that show the practical applicability of our algorithm. Finally, we show that the number of vertices can be reduced to O(k ^d?1) with additional processing in O(k ^1.5d ) time—nontrivially combining the sunflower technique with problem kernels due to Abu-Khzam and Moser.     

Weighted mean of a pair of clusterings

In this paper, we introduce the weighted mean of a pair of clusterings. Given two clusterings C ₁ and C ₂, the weighted mean of C ₁ and C ₂ is a clustering C _w that has distances d(C ₁, C _w ) and d(C _w , C ₂) to C ₁ and C ₂, respectively, such that d(C ₁, C _w ) + d(C _w , C ₂) = d(C ₁, C ₂) holds for some clustering distance function d. C _w is defined such that the sum of the distances d(C ₁, C _w ) and d(C _w , C ₂) is equal to the distance between C ₁ and C ₂. An algorithm for its computation will be presented. Experimental results on both synthetic and real data will be shown to illustrate the usefulness of the weighted mean concept. In particular, it gives a tool for the cluster ensemble techniques.