Research on Quality of Service Based Routing Protocols for Mobile Ad Hoc Networks

Quality of service (QoS) based routing protocols play a significant role in MANETs to maintain proper flow of data with efficient power consumption and without data loss. However, several network resource based technical challenges or issues are encountered in the design and implementation of QoS routing protocols that perform their routing function by considering the shortest route or the lowest cost. Furthermore, a secondary route is not reserved and alternative routes are not searched unless the established route is broken. The current structures of the state-of-the-art protocols for MANETs are not appropriate for today's high bandwidth and mobility requirements. Therefore, research on new routing protocols is needed, considering energy level, coverage, location, speed, movement, and link stability instead of only shortest path and lowest cost. This paper summarizes the main characteristics of QoS-based routing protocols to facilitate researchers to design and select QoS-based routing protocols. In this study, a wide range of protocols with their characteristics were classified according to QoS routing strategy, routing information update mechanism, interaction between network and MAC layer, QoS constraints, QoS guarantee type and number of discovered routes. In addition, the protocols were compared in terms of properties, design features, challenges and QoS metrics

EROZYONUN BELİRLENMESİNDE YÜZEYSEL AKIŞ PARSELİ KULLANIMININ İRDELENMESİ

Arazi ya da laboratuar koşullarında, yağmur altında veya yapay yağmurlama kullanılarak erozyon, toprak kaybı, yüzeysel akış veya infiltrasyon ölçümleri yapılan parseller, genel anlamda yüzeysel akış parselleri olarak adlandırılmaktadır. Yüzeysel akış parsellerinden güvenilir veri elde edebilmek için uyulması gereken birçok esas bulunmaktadır. Bunların en önemlileri; yüzeysel akış parselinin arazi üzerine tesisi, parsel boyutlarının belirlenmesi, çalışma amacına uygun parsel kullanımı, veri toplama yöntemi, ölçüm süresi ve sıklığı, yüzeysel akış ve sediment örneklemesinin usulüne uygun yapılması, karşılaşılan sorunlar ve bu sorunların nasıl giderileceği şeklinde sıralanabilir. Parsel çalışmalarında bu esasların çalışma amacına, yönteme, çalışma süresine, çalışmanın laboratuar ortamı ya da arazi üzerinde olmasına bağlı olarak oldukça değişken olduğu görülmektedir. Daha önce yapılan çalışmalardan yararlanılarak, yüzeysel akış parselleri yukarıda belirtilen esaslar çerçevesinde ele alınmış ve irdelenmiştir

EFFECTS OF LAND-USE CHANGE ON SOME HYDRO-PHYSICAL PROPERTIES OF SOILS

This study was conducted to determine the effects of different land-use types on hydro-physical properties of topsoil in Bartin-Iskalan Creek Catchment located in Western Black Sea region. Duplicate topsoil samples were taken using steel cylinders (400 cm 3) at 100 different sampling points from 3 different land-use types (34 from farmlands, 34 from rangelands and 32 from forests). Data were analyzed using ANOVA, and means were compared by Tukey's test. Results indicated that forests had the highest organic matter content (4.17%), total porosity (46.66%), water holding capacity (34.19%), hydraulic conductivity (24.75 cm/h), moisture content at field capacity (29.62%) and available water (6.94%), whereas rangelands had the lowest hydraulic conductivity (2.33 cm/h), water holding capacity (29.46%), total porosity (43.08%), and organic matter content (2.73%), and farmlands had the lowest moisture content at the field capacity (28.73%) and available water capacity (3.01%) in their topsoils

Impacts of land use conversion on soil properties and soil erodibility

WOS: 000256207900017PubMed: 18972693Land use conversion can affect natural ecological processes such as surface runoff and erosion. Therefore, it has potential to change soil stability. To investigate this process in depth, Iskalan creek catchment in the Black sea region, where excessive land use applications and erosion events have often occured, was selected as the study area. The objective was to determine the effects of land use conversion on soil properties, soil erodibility and the relationships among soil properties and some erodibility indices. Duplicate topsoil samples were taken by using steel cylinders at 100 different sampling points from three different land use types; 34 of them are in farmlands, 34 in rangelands and 32 in forestlands. Soil particle size distribution, loss of ignition, pH, electrical conductivity, skeleton percentage and three erodibility indices were determined. Data were analysed by using Pearson correlation analysis (at 95% and 99% significance level), ANOVA and Tukey's test at 95 % significance level. According to study results, land use conversion affects some properties of soils significantly. Loss of ignition of soils in forests was significantly higher than soils in farmlands and rangelands. Soil skeleton percentage in rangelands and farmlands were significantly different. The study results showed that there was significant difference between pH of soils in forests and farmlands (p<0.05). Pearson correlation analysis results showed significant correlations among erodibility indices and certain soil properties such as clay and sand fraction of soils (p<0.05 and p<0.01). Topsoils of the study area were sensitive to erosion according to all three erodibility indices. The most sensitive soils were in farmlands

A Comparison of Soil Losses Estimated Using Fallout Radionuclides and the USLE for the Omerli Watershed, Turkey

Soil erosion is a major degradation process in watersheds. Inappropriate land use is the main reason for soil loss by erosion and for the associated sedimentation of lakes and reservoirs in Turkey. Soil erosion rates are usually part of the information to be considered for land evaluation under special conditions and they are generally estimated using empirical or theoretical models. Fallout radionuclides (FRN's) provide a powerful new technique for obtaining empirical information on erosion rates that can be used for predicting the impacts of proposed land management strategies on soil erosion and sediment yield within river basins. The Universal Soil Loss Equation (USLE) is one of the most comprehensive methods for estimating soil erosion, but the USLE does not estimate deposition. The aim of the study reported in this contribution was to compare soil losses estimated using Cs-137 measurements and the USLE at the Pasakoy and Esenceli study sites in the Omerli dam catchment, which supplies drinking water for Istanbul city. Soil losses estimated usin Cs-137 were 9.62 and 3.32 t ha(-1) yr(-1) for upper slopes and 10.34 and 2.19 t ha(-1) yr(-1) for mid-slopes, in Pasakoy and Esenceli, respectively, while those calculated using the USLE were 11.53 and 16.21 t ha(-1) yr(-1) for upper slopes and 19.58 and 14.45 t ha(-1) yr(-1) for mid-slopes, in Pasakoy and Esenceli, respectively

Effect of vegetation change from native broadleaf forest to coniferous plantation on selected soil properties

The objective of this study was to examine the effects of vegetation change from a native broadleaf forest to a coniferous plantation on selected soil properties, including soil texture, pH, organic matter, total nitrogen (N), total phosphorus (P), exchangeable cations (Ca2+, K+, Na+), and cation exchange capacity (CEC). Results showed that the amount of clay particles, Ca2+, and K+ values significantly increased, whereas Na+, total N, and organic matter and soil pH values decreased on the treatment plot after vegetation change. Soil acidity also increased and soil textural group changed from moderately fine-textured soils (clay loam) to medium-textured soils (loam) under both control and treatment plots. Organic matter, total N, and Na+ values increased, whereas Ca2+ concentration decreased through time on the control plot. Soil pH, total P, K+, and CEC did not show significant changes through time on the control plot

Determination of soil loss by (CS)-C-137 fallout radionuclide in Omerli watershed of Istanbul, Turkey

Soil erosion and sedimentation in watersheds are usually part of the information to be considered for soil and water conservation measures. Soil loss is generally estimated with models or measured with plot studies. Although fallout radionuclides (FRN)(#) methodology provides a powerful technique for predicting the impacts of proposed land management strategies on soil erosion and sediment yield within river basins and estimates erosion based on fallout radioisotopes (Cs-137, Pb-210, Be-7) radioactivity; it is rarely used in Turkey. The aim of this study was to determine soil losses from different land use types with FRN's methodology by using caesium-137 radionuclide in selected study sites around Pasakoy (shrub) and Esenceli (rangeland) villages in the environs of Omerli watershed. Bulk and 2 cm-depth incremental soil core samples were collected from the reference and sloping areas in both study sites. Soil losses varied from 0.49 to 23.22 t ha(-1) yr(-1) for shrub-covered sites and from 0.44 to 7.23 t ha(-1) yr(-1) for rangelands. The data show that soil loss from shrub-covered site was greater than acceptable tolerance limit (10 t ha(-1) yr(-1)) for soils of the sites