Feature selection in high-dimensional data is one of the active areas of research in pattern recognition. Most of the algorithms in this area try to select a subset of features in a way to maximize the accuracy of classification regardless of the number of selected features that affect classification time. In this article, a new method for feature selection algorithm in high-dimensional data is proposed that can control the trade-off between accuracy and classification time. This method is based on a greedy metaheuristic algorithm called greedy randomized adaptive search procedure (GRASP). It uses an extended version of a simulated annealing (SA) algorithm for local search.In this version of SA, new parameters are embedded that allow the algorithm to control the trade-off between accuracy and classification time. Experimental results show supremacy of the proposed method over previous versions of GRASP for feature selection. Also, they show how the trade-off between accuracy and classification time is controllable by the parameters introduced in the proposed method.

<p>The Red Sea Trough (RST) is an inverted trough of low-pressure system at lower tropospheric levels over the northeast Africa and the Red Sea. The previous research conducted on the RST suggests that when this system is activated, heavy rainfall occurs in large parts of the eastern Mediterranean and southwest Asia. The main aim of this article is to investigate the way Rossby wave activity at the upper level troposphere and its interaction with the lower tropospheric circulation activate the RST.</p><p>This study was carried out in three stages: first, the climatological behavior of RST in winter (December to February) was studied and then, cyclones were identified and tracked in the northeast Africa and the Red Sea using a cyclone tracking scheme. In the second stage, the Rossby wave activity flux at the 300 hPa level was considered in the region. Finally, the interaction between the wave activity flux and the RST was investigated. Two critical phases for the wave flux entering the region were considered. The positive (negative) critical phase corresponds to the period when the highest (lowest) values of the wave activity flux enter the northeast Africa and Red Sea regions. The results show that, during the positive critical phase, the RST strengthens and extends to the northeast of the Mediterranean Sea and cyclogenesis is increased in the northeast of Africa and especially in the northeast of the Red Sea. The main reasons for this phenomenon can be deduced as follows:</p><p>With regard to the divergence of wave activity flux and its southward flux, the source of energy and activity needed for cyclogenesis and reinforcement of the RST is provided by the flux convergence core of the North Atlantic storm track. The results of the wave activity time series show that part of the activity from the northeast is integrated with the convergence core of the Mediterranean storm track, leading to enhancement of the cyclones in the northeast of the Red Sea and the extension of the RST to the northeast. But most of the activity joins the flux divergence core of the Mediterranean storm track in the west of the region and results in amplification of Sudan’s cyclones and activation of the RST along both the meridional and zonal directions; the important point to consider is that the wave activity flux entering the region is greater in the zonal direction. In addition to the southward propagation of the wave activity, the packets of flux convergence and divergence in the central North Atlantic are tilted in the northeast–southwest direction, indicating the dominance of anticyclonic Rossby wave breaking. Associated with the upper-level wave activity fluxes entering the region, there is jet enhancement and low-level cold advection from higher latitudes to the tropical and subtropical regions. The difference of RST between the positive and negative critical phases is turned out to be statistically significant with confidence levels of greater than or equal to 90%.</p>

<p>In recent history, the eastern Mediterranean and Saudi Arabia have experienced extreme precipitation events involving significant financial and human losses. An important subset of these events is associated with the activation of the Red Sea trough (RST). In this study, the effect and role of Rossby wave propagation during three cases (Dec 1993, Jan 2011 and May 1982) of the active RST is investigated. Meanwhile, the synoptic and dynamic factors related to the tropical-extratropical interaction and the lower and upper levels of troposphere are discussed for each event. The data used were extracted from the Era-Interim subsection of the ECMWF database with a time step of 6 hours and a spatial step of 80 km in both latitude and longitude directions.</p><p>Despite differences in humidity sources and the amount of hot and humid air ascent in each event, a general pattern can be deduced in all three events. The results show that in all events from a few days before the maximum rainfall, fluxes of heat and humidity are directed to Saudi Arabia and the eastern Mediterranean and the RST is strengthened and extended to the east of the Mediterranean Sea. At the same time, a trough with varying intensity at the level of 500 hPa in the eastern Mediterranean exerts a southward influence, which is caused by the anticyclonic Rossby wave breaking. At the upper levels, associated with the wave activity flux divergence and convergence areas of the Mediterranean storm track, higher amounts of Rossby wave activity enter the northeast region of Africa. Also the meridional convergence of the wave activity flux strengthens the meridional circulation in the north of the Red Sea. Increased horizontal wave activity flux to the northeast Africa and the Red Sea is led to increased head and humidity flux to the region. On the other hand, the weakening of the extension of the Azores high pressure over Africa facilitates the tropical and extratropical interactions over the region. Also in the north or northeast of the Red Sea, a surface low pressure is formed. Having a different source in each case, the mid-level troughs exhibit a northwest-southeast title with respect to the surface lows which lead to baroclinic development and intensification of precipitation events in the eastern Mediterranean and Saudi Arabia.</p><p><strong>Keywords: </strong>Extreme precipitation, Rossby wave activity flux, Mediterranean storm track, upper level trough, meridional circulation, baroclinic development</p>