This research proposed a model of Enhanced Distributed Channel Access (EDCA) scheme which is one of the techniques used in reducing collision and usually prioritized due to its contention window to determine the impact of distance change on the IEEE 802.11 ah standard. The proposed model was analyzed using the Markov Chain approach to determine the effect of distance change on collisions levels while the numerical were simulated using MATLAB. Moreover, the Markov chain solution was used to evaluate parameters such as throughput, energy consumption, and delay. The results showed the increment in RAW slot duration and the distance change for each station can reduce the performance on the standard and the scenario when the RAW slot duration was changed by 50 ms performed better than 100 ms and 250 ms.

Human activities on land have grown significantly changing the entire landscape, while most of the changes have occurred in the tropics. The change has become a serious environmental concern at the local, regional and global scales. The intensity, speed, and degree of land use / land cover (LULC) changes are nowadays quicker compared to the past because of the development of society. Moreover, the rapid increase in population resulted in disturbing a large number of landscapes on the Earth. The main objective of this study was to detect historical (1990– 2020) and predicted (2020–2050) LULC changes in the Welmel River Watershed, which is located in the Genale-Dawa Basin, South Eastern Ethiopia. The dataset of 1990, 2005, and 2020 was generated from Landsat 5, Landsat 7 and Landsat 8 respectively to determine the historical LULC map. The result of this study revealed that agriculture/ settlement increased by 6.85 km ²∙y ^–1, while forestland declined by 9.16 km ²∙y ^–1 over the last 31 years between 1990 and 2020. In the coming 31 years (by 2050), if the existing trend of the LULC change continues, agriculture/settlement land is expected to increase from 290.64 km ² in 2020 to 492.51 km ² in 2050 at the rate of 6.73 km ²∙y ^–1, while forestland is expected to shrink from 690.48 km2 in 2020 to 427.01 km ² in 2050 by a rate of 8.78 km ²∙y ^–1.

Software vulnerability life cycles illustrate changes in detection processes of software vulnerabilities during using computer systems. Unfortunately, the detection can be made by cyber-adversaries and a discovered software vulnerability may be consequently exploited for their own purpose. The vulnerability may be exploited by cyber-criminals at any time while it is not patched. Cyber-attacks on organizations by exploring vulnerabilities are usually conducted through the processes divided into many stages. These cyber-attack processes in literature are called cyber-attack live cycles or cyber kill chains. The both type of cycles have their research reflection in literature but so far, they have been separately considered and modeled. This work addresses this deficiency by proposing a Markov model which combine a cyber-attack life cycle with an idea of software vulnerability life cycles. For modeling is applied homogeneous continuous time Markov chain theory.

This study is a detailed lithofacies analysis of the Wiar and Leszczyny members of the deep-marine Ropianka Formation (Campanian–Paleocene) exposed in the Hucisko Jawornickie section of the Skole Nappe, Polish Carpathian Flysch. The sedimentary succession (>400 m thick) represents a channelized lobe complex that prograded at the base of submarine slope. Seven sedimentary facies are recognized as a record of the principa modes of sediment deposition. Based on their stratigraphic grouping and grain-size trends, six facies associations are distinguished as representing specific sub-environments of the depositional system: distributary channels, channel-mouth lobes, channel levees, crevasses and interlobe basin plain with crevasse splays. The individual facies associations are characterized statistically and their internal facies organization is analysed by the method of embedded Markov chains to reveal the time pattern of depositional processes. The environmental changes indicated by the vertical succession of facies associations are attributed to the autogenic processes of the distributary channel shifting within an aggrading lobe area and the lateral switching of depositional lobes. Eustatic influences are likely, but difficult to ascertain with poor biostratigraphic data. The bulk basinward advance of the base-of-slope system was probably due to a pulse of the tectonic narrowing of the synclinal Skole Basin.

The purpose of this paper is to investigate the effects of natural uncertainties and effective parameters on the stability of plate-type rock walls. For this, the effective factors and geo-mechanical properties in the study area were obtained using field experiments. Stability analysis of rock walls was investigated for 40 scenarios in dry and saturated states. These parameters were then evaluated using Easyfit software and Markov chain analysis and Monte Carlo simulation by Rock Plane software. Comparison of the results of numerical and uncertainty methods shows that the rock walls with 60-80 degree slope are stable; and In saturated state they require stability due to the reduction of shear strength. Fixation of the rock walls was also investigated, indicating an optimum angle of 30° for the installation of the rock screw. The results show that the Monte Carlo simulation provides a simpler interpretation and the uncertainty methods are more accurate and reliable than the numerical methods.