748 research outputs found
Enhancement AODV Routing Protocol at the VANET within an Urban Scenario
a vehicular ad hoc network (VANET) is a potential technology for supporting communication in vehicle-to-vehicle as well as vehicle-to-roadside units. Because of high mobility and periodic variations in the design of networks, creating a reliable routing strategy for these networks is one of the key challenges in VANETs. The Ad Hoc On-Demand Distance Vector (AODV) routing protocol's scalability and on-demand route discovery technique make it a popular choice in VANETs. However, AODV has limitations that might impair the performance of VANETs, including major control overhead and higher delays throughout the network. This work introduces an improved AODV routing protocol created especially for the VANETs. This paper analyzes the impacts of modifying the Contention Window (CW) settings for the density to discover ways to enhance the performance of the 802.11p transmission about receiving probabilities and latency. We show that the proposed CW specified in the IEEE 802.11p standard works well in almost all evaluated situations. The proposed protocol (P-AODV) also demonstrates robustness in extremely dynamic settings involving a range of traffic densities and patterns of movement
Connectivity Analysis in Vehicular Ad-hoc Network based on VDTN
In the last decade, user demand has been increasing exponentially based on modern communication systems. One of these new technologies is known as mobile ad-hoc networking (MANET). One part of MANET is called a vehicular ad-hoc network (VANET). It has different types such as vehicle-to-vehicle (V2V), vehicular delay-tolerant networks, and vehicle-to-infrastructure (V2I). To provide sufficient quality of communication service in the Vehicular Delay-Tolerant Network (VDTN), it is important to present a comprehensive survey that shows the challenges and limitations of VANET. In this paper, we focus on one type of VANET, which is known as VDTNs. To investigate realistic communication systems based on VANET, we considered intelligent transportation systems (ITSs) and the possibility of replacing the roadside unit with VDTN. Many factors can affect the message propagation delay. When road-side units (RSUs) are present, which leads to an increase in the message delivery efficiency since RSUs can collaborate with vehicles on the road to increase the throughput of the network, we propose new methods based on environment and vehicle traffic and present a comprehensive evaluation of the newly suggested VDTN routing method. Furthermore, challenges and prospects are presented to stimulate interest in the scientific community
Schultz and Modified Schultz Polynomials for Edge – Identification Chain and Ring – for Square Graphs
في البيان المتصل G، دالة المسافة بين أي رأسين من رؤوس البيان هي أقصر مسافة بينهما، كما تعرف درجة الرأس والتي يرمز لها بـ بأنها عدد الحافات الواقعة عليه. متعددة حدود شوالتز وشوالتز المعدلة تعرف كالاتي:
على التوالي، حيث أن المجموع يؤخذ لكل الازواج غير المرتبة من الرؤوس المختلفة في وأن هي المسافة بين الرأسين و في . في هذا البحث استطعنا الحصول على صيغ عامة لكل من متعددة حدود شوالتز وشوالتز المعدلة ودليليهما ومعدلهما لتطابق الحافة لسلسلة وحلقة للبيانات المربعة.
In a connected graph , the distance function between each pair of two vertices from a set vertex is the shortest distance between them and the vertex degree denoted by is the number of edges which are incident to the vertex The Schultz and modified Schultz polynomials of are have defined as:
respectively, where the summations are taken over all unordered pairs of distinct vertices in and is the distance between and in The general forms of Schultz and modified Schultz polynomials shall be found and indices of the edge – identification chain and ring – square graphs in the present work
An Efficient Model for Data Classification Based on SVM Grid Parameter Optimization and PSO Feature Weight Selection
The support vector machine (SVM) is a classifier with different applications due to its perfect experimental performance compared to other machine learning algorithms. It has been used mostly in pattern recognition, fault diagnosis, and text categorization. The performance of SVM is extremely dependent on the sufficient setting of its parameters such as SVM max-iteration and SVM kernel-type. Therefore, the choice of suitable initial parameters of SVM will result in a good performance and classification result. This paper introduces a new schema for optimizing SVM parameters using grid search and particle swarm optimization PSO feature weighting. The experimental results demonstrate that the new method obtained a high accuracy compared to the traditional SVM and other SVM-optimization methods
Comparison of Single and Group Jet Grouting Columns Capacity Based on Field Load Test and Theoretical Methods
The evaluation of axial capacity of jet grouted soil cement columns in soft soil is a complicated issue because it depends according to the number of factors such as, soil type, influence mixture between soil and grouting materials, nozzle jet energy, jet grouting and water flow rate, rotation and lifting speed. These parameters related to the type of jet grouting methods (single, double and triple system). Most methods of design the bearing capacity of the jet-grouting column based on experience. Therefore, some designer calculates the bearing capacity of the jet grouting column based on jet grout section capacity. In this paper, different theoretical methods have been used to estimate of the jet grouting soil-cement capacity, such as Poulos and Davis, 1980 methods and then their comparison with the pile load test calculations based on the quick pile load test as presented in ASTM-D1143-07. Therefore, the study describes a prototype test single and group jet grout soil-cement models of arrangement (1*1, 1*2 and 2*2) for total length to diameter ratios (L/D) is 13.33 and clear spacing three times of diameter has been constructed in soft clayey soils in the right bank of the Euphrates River, at Al- Nasiriyah city. As a result, the theoretical method for estimation the bearing capacity gives unfaithful values for the single and group jet grout column compared to the load- settlement calculations obtained from field pile load test data. On the other hand, the Hansen’s 90% and Butler and Hoy’s given closer results to each other and may be considered faithful interpretation methods to compute the bearing capacity of single and group jet grouting columns
Comparison of two hormone preparations on the reproductive performance of air breathing catfish Clarias batrachus (Lin.)
Two hormone preparations viz. Human Chorionic Gonadotropin (HCG) and pituitary gland (PG) suspension were compared for their comparative efficacy on the breeding performance of a air breathing catfish Clarias batrachus. It was found that HCG induced fish gave better ovulation response than PG. Both fertilization and hatching of eggs were significantly (p<O.Ol) higher in HCG treated fish than PG. On all consideration, HCG was found more suitable for induced breeding of C batrachus over PG
Patient satisfaction in outpatient medical care: the case of Iraq
Background: Healthcare providers are increasingly interested in patient satisfaction as an indicator to assess the quality of health services. This study investigates the level of satisfaction among Iraqi patients attending the outpatient (OP) clinic.
Methods: This was a cross-sectional study conducted from October to December 2019 among outpatient attendees in two busiest centers in Iraq. A convenience sample of 235 (response rate of 88.0%) completed the self-administered short-form patient satisfaction questionnaire (PSQ-18). The independent variables included socio-demographic, economic, and self-perceived health status. Data were analyzed in SPSS, where descriptive analysis (mean ± standard deviation) and univariate (independent sample t-test, ANOVA test) and multivariate linear regression “Enter technique” was done at 0.05 level of significance and 95% confidence interval.
Results: The mean age of respondents was 39.3 (±14.8). The sample was mostly women (55.3%), and 37.4% in the age group of 30-49 years. More than half of participants residing in the urban regions (54.5%) from families of monthly household income less than 500,000 Iraq Dinars (USD 400). However, the majority (70.6%) have the first visit to the OP clinic, and 53.6% self-perceived health as good or very good. Results of multiple linear regression showed that patients residents in rural regions (B= 5.4 , P <0.001), married (B= 4.8, P <0.001), unemployed (B= 4.7, P <0.001) and low educated (B= 1.5, P <0.051) exhibited higher service satisfaction score compared to urban residents, single, employed and high educated participants respectively. However, patients aged fifty years and more (B= -2.1, P <0.001) and those with poor health (B=-2.5, P <0.001) exhibited lower service satisfaction scores compared to young age patients and the healthy participants, respectively.
Conclusion: The high demand for the use of health resources in metropolitan cities by the rural population indicates inequality in the distribution of health services and an increase in the rural-to-urban displacement
Extreme returns and the investor’s expectation for future volatility: Evidence from the Finnish stock market
We examine the significance of
extreme positive returns of the previous month
(MAX) as a return predictor in the Finnish stock market. We show that high fear
months, i.e., months associated with the
investor’s high expectation for future volatility, are accompanying with low MAX
effect implying that investors reluctant to gamble in high MAX stocks when they have high expectation for future
volatility.</p
The mediating role of strategic foresight in the relationship between financial knowledge and strategic responses
This study aimed to clarify the mediating role of strategic foresight in its various forms (foresight, acumen, research) in the relationship between financial knowledge and strategic response in its dimensions (resource liquidity, business maturity, reactiveness and reactivity). To achieve this goal, this study was based on the descriptive analytical method, where the questionnaire was used to collect the primary data. (220) questionnaires were distributed to workers in the branches of commercial banks in the middle Euphrates cities (40) branches and (215) were retrieved from them. The results revealed that the adoption of financial knowledge enabled the organization, the study sample, to respond effectively to environmental dynamics through strategic foresight. Moreover, it was revealed that organizations that used financial knowledge were able to maximize their core competencies through strategic foresight, and thus provided added value to services efficiently over their competitors
Modeling the Effect of Sea Water Intrusion into Shatt Al-Arab River (Iraq)
في الآونة الأخيرة ،عانى شط العرب في البصرة / جنوب العراق من القيم العالية للمواد الصلبه الذائبة الكلية (TDS) في المياه بسبب انخفاض المياه العذبة الواردة من المصادر التي تسببت في تسرب الملوحة إلى شط العرب . الهدف من هذه الدراسة هو تتبع توغل مياه البحر من الخليج العربي إلى شط العرب. تم استخدام نموذج الانتقال أحادي البعد باستخدام HEC-RAS 5.0.5 للتعرف على دينامياكية TDS في شط العرب. تم أخذ أربع حالات لتقدير تسرب الملوحة إلى SAAR وهي ، التصريف المنخفض والعالي الذي يساوي 29 م 3 / ث و 103 م 3 / ث والتي تم إطلاقها من ناظم قلعة صالح مع المد المرتفع والمنخفض. يُلاحظ أنه إذا كان التصريف ضئيلاً ، فإن قيم المواد الصلبة الذائبة تتراوح بين 3000-4000 مجم / لتر على بعد 150 كم من المصب في حالة انخفاض المد والجزر الأعلى على التوالي ، وإذا كان التدفق في الحاله القصوى ، فإن المواد الصلبة الذائبة بين 1000- 2000 ملغم / لتر على بعد 150 كم من المصب في حالة انخفاض المد والجزر الأعلى على التوالي. يمكن الاستنتاج أن زيادة تصريف المياه العذبة الواردة إلى 103 م3 / ثانية وأكثر ، ستؤدي إلى منع تسرب الملوحة نحو مركز مدينة البصرة ، سواء في المد المنخفض أو المرتفع. تظهر النتائج التي تم الحصول عليها وصفًا جيدًا لتباين TDS من البحر باتجاه أعالي شط العرب . يسمح هذا النموذج بتقدير فوري لانتشار المواد الصلبة الذائبة نحو شط العرب ويمكن أن يساعد في ضمان توفير المياه الصالحة للشرب.Recently, the Shatt Al-Arab River (SAAR) in Basra/ south of Iraq, have suffered from high amounts of Total Dissolved Solids (TDS) in the water that is due to reducing the incoming fresh water from the sources which caused the salinity intrusion into the SAAR. The objective of this study is to track the seawater propagation from the Arabian Gulf into SAAR. One-dimensional transport model using HEC-RAS 5.0.5 has been used to making knowledge of the dynamics of TDS into the SAAR. Four cases were taken to estimate the salinity intrusion into the SAAR which were, the low and high discharge that equal to 29 m3/s and 103 m3/s which released from Qalat Saleh regulator with high and low tide. It is seen that if the flow is high, the TDS values were between 3000- 4000 mg/l in the case of lowest low tide and highest high respectively, and if the flow is low, the TDS between 1000- 2000 mg/l reach 150 km from the mouth in the case of lowest low tide and highest high respectively. It can be conclude that an increase of the incoming freshwater discharge to 103 m3/s, will lead to prevents the salinity intrusion towards the center of Basrah city, for both low and high tide.The obtained results show good describtion for the TDS variation from the sea towards the upstream of the SAAR. The model allows the immediate estimation of TDS propagation towards SAAR and can help to ensure the safe water supply to the province
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