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Search Results: 1 - 10 of 325785 matches for " S. Haider "
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Detection the Spectrum Holes in the Primary Bandwidth of the Cognitive Radio Systems in Presence Noise and Attenuation  [PDF]
Ahmed S. Kadhim, Haider M. AlSabbagh
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.510071
Abstract: Cognitive Radio (CR) and Dynamic Spectrum Access (DSA) represent two complementary developments that will refashion the world of wireless communication. In order to investigate the roles of knowledge representation and reasoning technologies in this domain, we have developed an experimental cognitive radio simulation environment. That is, a conventional radio when operating in a particular communications mode always follows the same procedure and either succeeds or fails at a given task. A cognitive radio, by contrast, can use knowledge of radio technology and policy, representations of goals, and other contextual parameters to reason about a failed attempt to satisfy a goal and attempt alternate courses of action depending upon the circumstances.
Microstructural Evaluation and Mechanical Properties of an Al-Zn-Mg-Cu-Alloy after Addition of Nickel under RRA Conditions  [PDF]
Haider T. Naeem, Kahtan S. Mohammed
Materials Sciences and Applications (MSA) , 2013, DOI: 10.4236/msa.2013.411088

The effects of nickel in improving the mechanical properties and microstructural of Al-Zn-Mg-Cu alloys produced by semi-direct chill casting were investigated. Aluminium alloys were homogenized at different temperatures conditions, which aged at 120°C for 24 h (T6 temper), and retrogressed at 180°C for 30 min and then re-aged at 120°C for 24 h (RRA). The results of the microstructural analyses showed that with adding nickel to aluminium alloy, nickel-rich dispersoid particles were formed, such as Al7Cu4Ni, Al4Ni3, Al75Ni10Fe15, Al3Ni2, and Al50Mg48Ni7. Intermetallics compounds within the matrix alloy led to dispersion and fine-grain mechanisms which prevent the recrystallization and grain growth. Enhancement of mechanical properties of the alloys study is obtained through the precipitation hardening of alloying elements of the base alloy besides Ni-bearing dispersoid particles. The microstructure of these alloys were examined through optical and scanning electron microscopy along with energy dispersive X-ray and X-ray

Totally Umbilical Screen Transversal Lightlike Submanifolds of Semi-Riemannian Product Manifolds  [PDF]
S. M. Khursheed Haider, Advin Maseih, Mamta Thakur
Advances in Pure Mathematics (APM) , 2012, DOI: 10.4236/apm.2012.24037
Abstract: We study totally umbilical screen transversal lightlike submanifolds immersed in a semi-Riemannian product manifold and obtain necessary and sufficient conditions for induced connection ▽ on a totally umbilical radical screen transversal lightlike submanifold to be metric connection. We prove a theorem which classifies totally umbilical ST-anti-invariant lightlike submanifold immersed in a semi-Riemannian product manifold.
Cylindrical versus Spherical Resonant Antennas for Gravitational Wave Detection
S. Alam,S. Haider,Aurangzeb
Physics , 1997,
Abstract: The principles and detection of gravitational waves by resonant antennas are briefly discussed. But the main purpose of this short note is to compare the two geometries of resonant antennas, the well-known cylindrical to the spherical type. Some features of a two sphere observatory are also discussed.
A hybrid learning algorithm for text classification
S. M. Kamruzzaman,Farhana Haider
Computer Science , 2010,
Abstract: Text classification is the process of classifying documents into predefined categories based on their content. Existing supervised learning algorithms to automatically classify text need sufficient documents to learn accurately. This paper presents a new algorithm for text classification that requires fewer documents for training. Instead of using words, word relation i.e association rules from these words is used to derive feature set from preclassified text documents. The concept of Naive Bayes classifier is then used on derived features and finally only a single concept of Genetic Algorithm has been added for final classification. Experimental results show that the classifier build this way is more accurate than the existing text classification systems.
Phytoplankton Index of Biological Integrity (P-IBI) in Several Marshes, Southern IRAQ  [PDF]
Bahram K. Maulood, Abdul Hameed M. Jawad Alobaidy, Azhar Alsaboonchi, Haider S. Abid, Ghasak S. Alobaidy
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.24043
Abstract: Indices of Biological Integrity (IBIs) are being increasingly used as useful and direct tools for assessing general health of aquatic ecosystems. Although such ecosystems in Iraq, especially the southern marshes, underwent severe alterations during the last two decades, including extensive desiccation in the 1990s, such tools are largely lacking. Phytoplankton Index of Biological Integrity (P-IBI) was developed from data collected seasonally from 2005 up to 2007 in different sites of the southern marshes of Iraq to evaluate the trend of these ecosystems based on phytoplankton data. Ten metrics were selected for measuring P-IBI for the first time in Iraq as a proposed project from Nature Iraq and Twin Rivers Institute, American University of Iraq-Sulaimani. Although generally fluctuated both spatially and temporally, mean P-IBI scores showed better conditions in Al Hawizeh marsh (Good) as compared to the Central and West & East Al Hammar marshes (Fair to Good). However, the results generally indicated evidence of improvement at the Central and West & East Al Hammar marshes, whereas no recovery of the status of water was evident throughout the data obtained at Al Hawizeh marsh. Values were generally higher in winter. These observations clearly reflect the relative stability of the Hawizeh marsh ecosystem which was not subject to the desiccation process in the 1990s, while the severely dried systems of the Central and Hammar marshes are showing positive responses to the restoration efforts that were started after 2003. Among the ten metrics comprising the index, relative abundance of diatoms had the most prominent effect on the P-IBI value in the three marshes. Metrics such as chlorophyll- a concentration and relative abundance of Cyanophyta and Chlorophyta also played a significant role in determining the index value. Continuous monitoring based on the selection of the most suitable metrics is recommended.
Application of Water Quality Index for Assessment of Dokan Lake Ecosystem, Kurdistan Region, Iraq  [PDF]
Abdul Hameed M. Jawad Alobaidy, Haider S. Abid, Bahram K. Maulood
Journal of Water Resource and Protection (JWARP) , 2010, DOI: 10.4236/jwarp.2010.29093
Abstract: Water Quality Index (WQI) was applied in Dokan Lake, Kurdistan region, Iraq using ten water quality parameters (pH, Dissolved Oxygen, Turbidity, Conductivity, Hardness, Alkalinity, Sodium, Biochemical Oxygen Demand, Nitrate and Nitrite). The relative weight assigned to each parameter ranged from 1 to 4 based on the importance of the parameter for aquatic life. The results indicated that water quality of Dokan Lake declined from Good in the years 1978, 1979, 1980, 1999, 2000 and 2008 to Poor in 2009. The impact of various anthropogenic activities was evident on some parameters such as the EC and BOD. It is suggested that monitoring of the lake is necessary for proper management. Application of the WQI is also suggested as a very helpful tool that enables the public and decision makers to evaluate water quality of lakes in Iraq.
Primary hepatic lymphoma presenting as fulminant hepatic failure with hyperferritinemia: A case report
Fyeza S Haider, Robert Smith, Sharif Khan
Journal of Medical Case Reports , 2008, DOI: 10.1186/1752-1947-2-279
Abstract: We present the case of a middle-aged woman exhibiting pancytopenia, hyperferritinemia and rapidly deteriorating to develop acute hepatic failure. Her initial clinical picture led to a working diagnosis of adult onset Still's disease with probable hemophagocytic syndrome before her worsening liver function necessitated a percutaneous liver biopsy and establishment of the final diagnosis of primary hepatic lymphoma.Primary hepatic lymphoma is an uncommon malignancy and its manifestation as progressive hepatitis or acute fulminant hepatic failure can be difficult to diagnose. The presence of constitutional symptoms, pancytopenia and high ferritin levels can complicate the evaluation process. A liver biopsy early in the course of liver dysfunction may establish the diagnosis without a higher risk of bleeding complications seen once liver failure sets in.Primary Hepatic Lymphoma (PHL) is a rare variant of non-Hodgkin's lymphoma with an incidence of < 1%. The presence of diffuse hepatic involvement is uncommon and therefore presentation as hepatocellular jaundice or acute fulminant hepatic failure is rare.We present a case where persistent fever, non-specific symptoms, pancytopenia and strikingly high levels of serum ferritin preceded the presentation of acute liver failure. Due to these findings, alternative diagnoses were entertained including hemophagocytic syndrome in association with adult onset Still's disease (AOSD).A 53-year-old Caucasian woman was transferred to our facility for 3 weeks of intermittent fevers, chills, weight loss, myalgias and arthralgias. She had mild epigastric discomfort with nausea and vomiting. Dalteparin and warfarin were started for a recently diagnosed pulmonary embolism. Her past history was remarkable for diabetes mellitus type 2, hypertension and villous adenoma of the colon. Subsequent colonoscopies were normal. Except for mild epigastric tenderness, her physical examination findings were normal. White blood cell (WBC) count was 4.5 K
Influence-Number of Antennas on the Total Sensing Time in Cognitive Radio Systems
Ahmed S. Kadhim,Haider M. AlSabbagh
Journal of Emerging Trends in Computing and Information Sciences , 2011,
Abstract: In the cognitive radio (CR) systems the total scanning time that is the time taken by the receiver to sense the spectrum is one of the issues in perspective of the overall system performance. This paper proposes architecture for a dedicated receiver capable to reduce sensing time with using dual part: the main receiver and a dedicated one, each with multiple antennas (M). The achieved results show that the total sensing time is reduced by approximately 1/M with using the proposed structure.
Dual band MSA designs for GPS and GSM applications
Haider A. Sabti,Jabir S. Aziz
Journal of Engineering and Applied Sciences , 2010,
Abstract: New designs of obtaining a dual frequency bands antenna operate on the dual frequency bands of Global Positioning System (GPS) and Global System for Mobile Communications (GSM) with a single-feed square micro-strip antenna are proposed and experimentally studied. The proposed designs are based on the different patch dimensions loaded with four rectangular slots in the form of cut from the sides of the square patch. The result of this work shows that the slots loaded into the square patch antennas offers further size reduction with multiband properties that can be used in GPS and GSM applications. Details of the design considerations of the proposed antennas are described, and experimental results of the obtained dual-band performances are presented and discussed.
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