Qatar Foundation Annual Research Forum Volume 2012 Issue 1
- تاريخ المؤتمر: 21-23 Oct 2012
- الموقع: Qatar National Convention Center (QNCC), Doha, Qatar
- رقم المجلد: 2012
- المنشور: ٠١ أكتوبر ٢٠١٢
321 - 340 of 469 نتائج
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Analysis of mobility impact on interference for short-range cognitive radio networks
المؤلفون: Ali Riza Ekti, Erchin Serpedin and Khalid A QaraqeBackground & Objectives: Cognitive radios (CRs) strive to utilize the white holes in the radio frequency (RF) spectrum in an opportunistic manner. Because interference is an inherent and a very critical design parameter for all sorts of wireless communication systems, many of the recently emerging wireless technologies prefer smaller size coverage with reduced transmit power in order to decrease interference. Prominent examples of short-range communication systems trying to achieve low interference power levels are CR relays in CR networks and femtocells in next generation wireless networks (NGWNs). It is clear that a comprehensive interference model including mobility is essential especially in elaborating the performance of such short-range communication scenarios. This work focuses on analyzing how interference evolves in time under long and short term fading. Such an analysis is essential, because once the interference behavior is understood, it can be managed in a better way. Also, NGWNs and CRs can be designed in such a way that arduous and expensive planning stage is omitted. This way, deployment costs can be reduced drastically. Methods: It is known that received signal in a general wireless propagation environment includes the effects of both long- and short-term fading. Therefore, a logarithmic transformation reveals the individual impact of each fading phenomenon. The two-dimensional (2D) random walk model is incorporated into the physical layer signal model. Results: The results show that relatively larger displacements in short primary-user-receiver (PU-Rx) and secondary-user-transmitter (SU-Tx) separations lead to drastic power level fluctuations in the observed interference power levels. The impact of path loss is one of the major factors changing the future interference conditions for low-speed mobility scenarios especially within short communication ranges. Conclusions: It is shown that long-term fading plays a crucial role for the temporal evolution of interference for NGWNs and CRs. By using the interference statistics, the design and deployment of future cellular mobile radio systems in Qatar could be optimized. This is crucial, especially for rapidly changing network topographies as is the case with the city of Doha. Even for well-established network topographies, the proposed method provides an analytical way of examining and managing the interference.
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Image processing on the Cloud: Characterizing edge detection on biomedical images
المؤلفون: Majd Sakr, Mohammad Hammoud and Manoj Dareddy ReddyIn order to analyze and deduce valuable information from big image data, we have developed a framework for distributed image processing in Hadoop MapReduce. A vast amount of scientific data is now represented in the form of images from sources like medical tomography. Applying algorithms on these images has been continually limited by the processing capacity of a single machine. MapReduce created by Google presents a potential solution. MapReduce efficiently parallelizes computation by distributing tasks and data across multiple machines. Hadoop, an open source implementation of MapReduce, is gaining a widespread popularity due to features such as scalability and fault tolerance. Hadoop is primarily used with text-based input data. Its ability to process image data and its performance behavior with image processing have not been fully explored. We propose a framework that efficiently enables image processing on Hadoop and characterizes its behavior using a state-of-the-art image processing algorithm, Edge Detection. Existing approaches in distributed image processing suffer from two main problems: (1) input images need to be converted to a custom file format and (2) image processing algorithms require adherence to a specific API that might impose some restrictions on applying some algorithms to Hadoop. Our framework avoids these problems by: (1) bundling all small images into one large file that can be seamlessly parsed by Hadoop and (2) relaxing any restriction by allowing a direct porting of any image processing algorithm to Hadoop. A R educe-less job is then launched where the code for processing images and a mechanism to write the images back individually to HDFS are included in Mappers. We have tested the framework using Edge Detection on a dataset of 3760 biomedical images. Besides, we characterized Edge Detection along several dimensions, such as degree of parallelism and network traffic patterns. We observed that varying the number of map tasks has a significant impact on Hadoop's performance. The best performance was obtained when the number of map tasks equals the number of available slots as long as the application resource demand is satisfied. Compared to the default Hadoop configuration, a speedup of 2.1X was achieved.
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Analysing existing set theoretic and program specification diagrams
المؤلفون: Noora Fetais and Peter ChengThis research is aimed at evaluating the usability of notational systems that are used for specifying programs. We provide a conceptual analysis of the development of constraint diagrams (CD) as a diagrammatic notation which developed to support program specification. A detailed analysis of multi-case comparisons of formal languages and graphical systems for expressing logic and program constructs was conducted in order to trace how the development of the notations overcame the limitations of earlier generations of notations. By following the evolution of logic diagrams, we consider why and how they have been successively revised to increase their expressivity or their ease of comprehensibility and use. Visualizations of logic were proposed over the centuries. Leonhard Euler presented Euler diagrams, John Venn generalized Euler diagrams and presented Venn diagrams, and Charles Peirce extended Venn diagrams by increasing their expressiveness and presented Venn-Peirce diagrams. The modifications from Peirce to Shin concentrate on restoring visual clarity, but without loss of expressive power. Based on that, Constraint Diagrams were presented by Stuart Kent for constraint specification, behavioural specification, and relational navigation. We found that the gradual changes in diagrams from Euler Circles through Venn, Peirce, Shin to Constraint Diagrams share three complementary common themes: (1) to increase the expressiveness, (2) to increase the logical power of the formality of the system, and (3) to enhance the visual clarity. Depending on the purpose of designing a diagram, the priority of a theme over other themes is granted. For example, both Venn and Peirce adopted the same kind of solution in order to achieve these improvements: to introduce new syntactic objects, that is, shadings by Venn, and x's, o's, and lines by Peirce. However, on the negative side, these revised systems suffer from a loss of visual clarity, mainly because of the introduction of more arbitrary conventions. The modifications from Peirce to Shin concentrate on restoring visual clarity, but without loss of expressive power. The extension from these diagrams resulted in CD, which allows relational navigation (expressions involving two place predicates), is more expressive than previous diagrams, and has higher visual clarity and logical power.
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Empirical evaluation of constraint diagrams notation
المؤلفون: Noora Fetais and Peter ChengAn empirical evaluation of constraint diagrams (CD) as a program specification language is conducted by comparing it to natural language (NL) with computer science students included two experiments, one on the interpretation of CD to evaluate the comprehension of notational system, and the other on the construction of program specifications. The first experiment took the form of a web-based competition in which 33 participants were given instructions and training either on CD or on equivalent NL specification expressions. After each example, they responded to three multiple-choice questions requiring the interpretation of expressions in their particular notation. Although the CD group spent more time on the training and had less confidence, they obtained comparable interpretation scores as the NL group and took less time to answer the questions, although they had no prior experience of CD notation. In the second experiment, which focused on the construction of CD, 20 participants were given instructions and training either on CD or on equivalent NL specification expressions. After each example, they responded to three questions requiring the construction of expressions in their particular notation. We built a mini-editor to allow the construction of the two notations, which automatically logged their interactions. Although the CD group supplied more accurate answers, they spent more time in answering the questions. The NL group supplied answers that were partially correct but with some missing information. Moreover, the CD group had spent more time in training, but their returns to the training examples were fewer than the NL group.
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Minimum-selection maximum ratio transmission schemes in underlay cognitive radio systems
المؤلفون: Zied Bouida, Ali Ghrayeb and Khalid QaraqeUnder the scenario of an underlay cognitive radio network, we introduce the concept of minimum-selection maximum ratio transmission (MS-MRT). Inspired by the mode of operation of the minimum-selection generalized selection combining (MS-GSC) technique, the main idea behind MS-MRT is to present an adaptive variation of the existing maximum ratio transmission (MRT) technique. While in the MRT scheme, all the transmit antennas are used for transmission, and only a subset of antennas verifying the interference constraint to the primary receiver in MS-MRT are adaptively selected and optimally beamformed in order to meet a given modulation requirement. The main goal of these schemes is to maximize the capacity of the secondary link while satisfying the bit error rate (BER) requirement and a peak interference constraint to the primary link. The performance of the proposed schemes is analyzed in terms of the average spectral efficiency, the average number of antennas used for transmission, the average delay, and the average BER performance. These results are then compared to the existing bandwidth efficient and switching efficient schemes (BES and SES, respectively). The obtained analytical results are then verified with selected numerical examples obtained via Monte-Carlo simulations. We demonstrate through these examples that the proposed schemes improve the spectral and the delay performance of the SES and BES schemes and fit better to delay sensitive applications. The proposed schemes also offer better processing-power consumption than the MRT schemes since a minimum number of antennas is used for communication in the MS-MRT schemes. The MS-MRT techniques represent power and spectral efficient schemes that can be extended to more practical scenarios. As an example, these schemes can be studied in the context of Long term Evolution (LTE) Networks where adaptive modulation, beamforming, and interference management are of the major enabling Techniques.
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Wireless smart home monitoring and surveillance system
المؤلفون: Duaa Abdullah AbumaaliWireless technology such as GSM/GPRS and Wi-Fi has taken on an important role in our daily life. The noticeable improvement of these technologies has led to advancement in home automation, where people can enjoy comfort and secure living places. This project proposes a ZigBee-based cost effective solution to control and monitor home appliances remotely and to enable home security against intrusion in the absence of a homeowner using the wireless sensor network kit from national instruments. A wireless sensor network, connected to a GSM modem, can send and receive alarming and controlling SMSs and remotely control the system using an internet web page. Also a security camera is embedded within the system to send alarm SMS and snap an image in case of a visitor or intruder. The system is implemented and evaluated among different sample applications spanning home security, climate control, hazard alarming, and appliance control with remote access and control features to demonstrate the feasibility and effectiveness of the proposed system. Moreover a small-scale live demo model of the smart house is constructed to proof the concept
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Malware.inc: analyzing the security of popular web/mobile frameworks
المؤلفون: Talal Al Haddad, Manoj Reddy, Fahim Dalvi, Baljit Singh, Ossama Obeid, Rami Al Rihawi, Omar Abou Selo, Aly Elgazar and Thierry SansBackground and Objectives: A new generation of software emerged with mobile devices, cloud computing and the web. New usages come with new security threats, and a new generation of malware (malicious software) is emerging as well. Recent security reports show that these malware are on the increase. The goal of this project is to evaluate the risk of exposure to malware in popular app ecosystems such as Apple iOS, Google Android, Facebook, Google App Engine, Mozilla Firefox and Google Chrome. Methods: Eight students from Carnegie Mellon Qatar participated in this project. Each looked at a specific technology (either iOS, Android, Facebook, Google App, Mozilla Firefox or Google Chrome). The researchers learned how to develop applications and, as proof of concept, developed several malware apps that were able to steal user's personal information. One collects logins, passwords and credit card numbers from user's Gmail. One collects user's private information on Facebook and propagates through the victim's friends. One records the "clicking" passwords that users enter on online banking websites. One records keystrokes made on the computer without being detected by existing antivirus. One is an Android app that records people conversations while the phone is on standby mode. Results: Based on these experiments, we were able to assess the risks and analyze the security issues of these popular apps that we use everyday. These preliminary results were presented at 6th INTERPOL's Group meeting-MENA Region conference in Doha (March 22nd). We plan to publish the scientific results during the Fall of 2012. As future work, the security expertise gained during this project will allow us to design new security tools to protect users against these new kinds of malware. Conclusion: Qatar offers many services related to e-government, e-business, e-education and e-health through web portals and mobile applications. Deploying such a global infrastructure requires a strong security assurance. This project contributes to this vision by developing a local expertise on cyber security.
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Variations in giving directions across arabic and English native speakers
المؤلفون: Huda Gedawy, Micheline Ziadee and Majd SakrThis work explores the differences in direction-giving strategies between two groups, native Arabic and native English speakers. This study will help influence design decisions for multi-lingual, cross-cultural human robot interaction. There are clear cultural influences on modes of communication. Previous research studies found that direction-giving techniques and strategies vary between different cultural groups. Burhanudeen compared Japanese and English native speakers and found that locator remarks are more frequently used by Japanese natives, while the use of directives is more common with English natives. In this work, we examine the discourse for navigation instructions of members of two target groups, Arabic native speakers and English native speakers. We address the following questions: How do languages and strategies used for providing directions vary between these two groups? What are the differences and what are the similarities? Are there any possible gender-related differences in giving directions? We recorded 56 participants giving oral direction instructions for three specific locations at the Carnegie Mellon Qatar campus, and 33 participants giving oral direction instructions for three different locations at the Student Center. We transcribed the audio recordings and annotated our transcriptions. We categorized the spatial perspectives used by participants into route perspective which involves the use of left/right turns and landmarks, and survey perspective, which involves the use of units (time and distance) and cardinals (north, south, east and west). Our analysis also included number of pauses, repetitions, error corrections, number of words and intermediate details. Our results showed that the way-finding strategy favored by English natives and Arab natives is the landmark-based navigation strategy. However, English natives had a higher frequency of using cardinals, pauses and intermediate information while Arab natives used units of distance, left/right turns and error corrections more frequently than English natives. Male participants from both groups are more likely to rely on survey perspective than female participants. Based on these results, we conclude that culture, language, and gender influence a speakers discourse and strategy for giving directions.
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Enhanced formulations for the arrival-departure aircraft scheduling problem
المؤلفون: Sara Yousef Al-Haidous, Ameer Al-Salem, Mohamed Kharbeche and Fajr Al-AnsariBackground and Objectives: The target of this work is to construct a mathematical model to help resolve aircraft scheduling over multiple runways. This problem is considered a hard topic in transportation research due to the constantly increasing aviation traffic volume around the world. Surprisingly, although there exists an impressive amount of literature for the landing and arrival cases, there is no proposed exact solution to solve this problem. Therefore, the main contribution of this work is to present exact methods involving exact procedures specifically related to this complex arrival-departure variant. This method will solve the problem optimally based on mixed-integer linear formulation with the constraints of limited time windows and separation constraints. The project was funded by Qatar Foundation. Our objective for the investigation stems from its practical relevance to airports where good scheduling increases the airport capacity, maintains a good level of safety and reduces the controller's workload. Methods: We formulated a basic aircraft sequencing model using a mixed-integer linear formulation. Then, we proposed another model by adding valid inequalities, combining constraints and removing some variables. All these mathematical models are based on linear ordering feature. These models were solved using the mathematical programming language AMPL. Then, we solved them using a professional solver CPLEX. Results: We investigated the efficacy of reformulation arrival-departure scheduling problem over multiple runways. The results show that the solver is very effective in obtaining optimal solutions. In fact, the experimental tests reveal that most of instances are solved to optimality within a short time. In addition, we realized that adding the valid inequality constraint among the model yields less CPU ( Central Processing Unit) time and less number of nods. Conclusion: We proposed linear ordering formulations for the problem of minimizing total weighted tardiness to sequence arrival-departure aircraft over multiple runways. We presented the results of computational study that were carried out on a large variety of random instances and that shows the importance of reformulating the same problem. Interestingly, we observed that the proposed models enable us to optimally solve problems with up 15 aircraft and four runways.
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Performance analysis of cognitive radio multiple-access channels over dynamic fading environments
المؤلفون: Sabit Ekin, Khalid A. Qaraqe and Erchin SerpedinDue to the requirement of high data rates and broad utilization of wireless technologies (e.g., 3G, 4G and beyond), the radio frequency (RF) spectrum has become a very limited resource for modern wireless communication systems. Studies indicate that the spectrum is being under-utilized. As a promising solution, cognitive radio (CR) is an encouraging candidate to achieve more efficient RF spectrum utilization. The previous studies motivate us to utilize the dynamic channel fading model (hyper-fading) to perform a unified analysis for CR multiple-access channel (CR-MAC) networks. Since the nature of the CR networks is multiuser communication, deliberating CR-MAC is more pertinent than point-to-point communication systems. The objective is to maximize the capacity of CR-MAC network over hyper-fading channels under both secondary user's (SU's) transmit power (TP) and interference temperature (IT) constraints. Multiple SUs transmit to the secondary base station under the TP and IT constraints. In order to perform a general analysis, a theoretical dynamic fading model termed hyper-fading model, which is suitable to the dynamic nature of cognitive radio channel, is considered. The optimal power allocation method (water-filling) is employed to maximize the capacity of CR-MAC for hyper-fading channel with TP and IT constraints. Throughout the results, the capacity of the hyper-fading channels are compared with that of other channel fading models such as Rayleigh, Nakagami-2, and with an AWGN channel. Furthermore, the impact of the number of SUs on capacity is investigated. Numerical results along with relevant discussions for capacity measure under AWGN, and Rayleigh, Nakagami-2 and hyper-fading channel models are provided to compare the behavior of CR-MAC in these environments. The results reveal that in the case of very strict IT constraint the water-filling method gives good capacity improvements. This benefit is lost when the IT constraint is relaxed. Through comparison of hyper-fading with other fading environments, it is found that the hyper-fading channel fills the gap in the capacity profiles obtained from the other channel fading types. Further, a study of such a CR-MAC system that undergoes a hyper-fading model can provide unified and comprehensive insights on performance analysis of the CR networks.
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New perspectives, extensions and applications of De Bruijn identity
المؤلفون: Sangwoo Park, Erchin Serpedin and Khalid QaraqeTwo significant identities-de Bruijn and Stein-were independently studied in information theory and statistics. De Bruijn identity shows a connection between two fundamental concepts in information theory and signal processing: differential entropy and Fisher information. On the other hand, Stein identity represents a relationship between the expectation of a function and its first-order derivative. Due to their several applications in statistics, information theory, probability theory, and economics, de Bruijn and Stein identities have attracted a lot of interest. In this study, two different extensions of de Bruijn identity and its relationship with Stein identity will be established. In addition, a number of applications using de Bruijn identity and its extensions will be introduced. The main theme of this study is to prove the equivalence between de Bruijn identity and Stein identity, in the sense that each identity can be derived from the other one. In a particular case, not only are de Bruijn and Stein identities equivalent, but they are also equivalent to the heat equation identity, which is another important result in statistics. The second major goal of this study is to extend de Bruijn identity in two distinctive ways. Given an additive non-Gaussian noise channel, the first-order derivative of differential entropy of the output signal is expressed as a function of the posterior mean, and the second-order derivative of differential entropy of the output signal is represented in terms of Fisher information. The third most important result is to introduce practical applications based on the results mentioned above. First, two fundamental bounds-the Bayesian Cramér-Rao lower bound (BCRLB) and the Cramér-Rao lower bound (CRLB)-in statistical signal processing, and a novel lower bound, tighter than BCRLB, are presented. Second, Costa's entropy power inequality is proved in two distinctive ways. Finally, min-max optimal training sequences for channel estimation and synchronization in the presence of unknown noise distribution are designed.
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Performance of digitally modulated RFID energy detector for moisture sensing applications for oil and gas quality monitoring in Qatar
المؤلفون: Adnan Nasir, Ali Riza Ekti, Khalid A Qaraqe and Erchin SerpedinBackground & Objectives: Advances in the radio frequency identification (RFID) technology have made it ubiquitously present. Due to the recently emerging applications, RFIDs have been used in a plethora of different scenarios. Oil and gas industry is no exception; developments in the RFID technology enabled it to be used in oil and gas quality and pipeline infrastructure monitoring through low frequency RFID tags. The presence of moisture in liquefied petroleum gas (LPG) / liquefied natural gas (LNG) pipes can create two main problems. It can degrade the heating ability of the fuel and it can also react with the refrigerant of the liquefied gas to create hydrates, which further lower the quality of the gas. A wireless monitoring system using low frequency RFIDs as moisture sensors can prevent such hazards by detecting the received energy of the transmitted signal to determine the presence of moisture. Method: A simple energy detector concept was utilized to exploit the well-known behavior of the RFID's signal reception and energy absorption with varying environments. A decision for the presence of moisture was made using the threshold values of the energy detector. Results: The experimental results show that the energy detector approach detects the presence of moisture in the oil and gas system. As another remark, when we decrease the distance between the receiver and transmitter antennas of RFID sensors, one can easily notice the increase on the energy detection performance. Different power levels, modulation schemes and frequency ranges have been analyzed to better understand the energy detection output of RFID system. An optimized solution can be looked at for using the best frequency and input power to maximize the distance between the two antennas. Conclusion: In this study, one can see that the RFID system can be used to send information regarding the presence of moisture for quality monitoring of liquefied gas pipes in Qatar. By using this information, we can detect and make decisions on the basis of the energy detection output from the RFID antenna system. This study can be used in a wireless cyber-physical moisture detection system targeted at Qatar's needs.
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Outage and SER performance of an opportunistic multi-user underlay cognitive network
المؤلفون: Fahd Ahmed Khan, Kamel Tourki, Mohamed-Slim Alouini and Khalid QaraqeHaving multiple users gives rise to multi-user diversity which can be exploited to give good quality-of-service to each user in the network and also increase the overall capacity of the network. In a spectrum-sharing setting, the multi-user diversity can be exploited; however, this is different from the traditional multi-user case because of the interference power constraints imposed on the secondary users. In this work, we consider a multi-user underlay cognitive network, where multiple cognitive users concurrently share the spectrum with a primary network, and a single secondary user is selected for transmission. The channel is assumed to have independent but not identical Nakagami-m fading. Considering an interference power constraint and a maximum transmit power constraint on the secondary user, a power allocation policy is derived based on the peak interference power constraint. For this policy the secondary user transmitter (SU-Tx) requires the instantaneous channel state information (CSI) of the link between the SU-Tx and the primary user receiver (PU-Rx). The advantage of this scheme is that the interference constraint is never violated and there is no loss of performance of the primary network. The user is selected for transmission based on a greedy scheduling scheme where the user with the highest instantaneous signal-to-noise ratio is chosen for transmission. For this user scheduling scheme, we analyze the uplink performance of the multi-user underlay secondary network in terms of outage probability and symbol error rate (SER). Exact closed-form expressions for the outage performance, moment-generating-function and SER performance of a multi-user cognitive network are derived. These expressions are obtained for an independent but non-identical distributed (i.n.i.d) Nakagami-m fading channel which is a more generic fading model and can cover a variety of fading environments including Rayleigh fading. Numerical results based on Monte-Carlo simulations are presented to verify the derived results. It is shown that the SER reduces as the peak interference power constraint is relaxed. Furthermore, as the number of users increases the SER reduces. If the interference power constraint is relaxed the power allocated becomes constant depending on the peak transmit power and thus the SER also becomes constant.
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Experimental analysis of energy detection for digitally modulated signals: Indoor measurements
المؤلفون: Ali Riza Ekti, Erchin Serpedin and Khalid A QaraqeBackground & Objectives: Spectrum sensing is a feature of cognitive radio (CR) systems which is proposed to improve spectral utilization of wireless signals. One of the sensing methods is the non-coherent energy detector, and even though it is computationally more effective than coherent methods, it has critical drawbacks, e.g. requirement of certain signal-to-noise ratio and number of samples. Moreover, type of digital modulation employed also affects the performance of the energy detectors. Therefore, the performance of the energy detectors is investigated for phase shift keying (PSK) and quadrature amplitude modulated (QAM) signals. Such an analysis is essential, because once the performance of the different modulated signals are understood; next generation wireless networks (NGWNs) and CRs can be designed in such a way that the arduous and expensive planning stage is omitted. This way, a higher data rate can be achieved by using the proper modulation type and/or order for indoor CRs and NGWNs. Methods: Instead of false alarm and missed detection analysis, probability mass function vs. energy detection statistics are introduced to better understand the effect of modulation type, order and wireless channel. A measurement setup is developed to consider line-of-sight and non-line-of-sight conditions. Signals are constructed, transmitted and recorded based on the signal model provided. All experiments took place in the Wireless Research Laboratory of the department of ECEN at Texas A&M University at Qatar. Results: The results show that performance of the energy detector changes drastically with the digital modulation scheme employed at the transmitter side. Another interesting point is the impact of the used energy detector samples (N). As expected, with the increase in N, the impact of central limit theorem (CLT) can be felt in a clearer way as well. Conclusions: By using the experimental results, the design and deployment of future cellular mobile radio systems such as femtocells in Qatar could be optimized. This is crucial, since most communications such as voice/internet/text traffic occur inside buildings especially for rapidly changing network topographies as is the case with the city of Doha. This way, data rate and speed can be optimized for the indoor environments.
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Efficient parallel implementation of the SHRiMP sequence alignment tool using MapReduce
المؤلفون: Rawan AlSaad, Qutaibah Malluhi and Mohamed AbouelhodaWith the advent of ultra high-throughput DNA sequencing technologies used in Next-Generation Sequencing (NGS) machines, we are facing a daunting new era in petabyte scale bioinformatics data. The enormous amounts of data produced by NGS machines lead to storage, scalability, and performance challenges. At the same time, cloud computing architectures are rapidly emerging as robust and economical solutions to high performance computing of all kinds. To date, these architectures have had limited impact on the sequence alignment problem, whereby sequence reads must be compared to a reference genome. In this research, we present a methodology for efficient transformation of one of the recently developed NGS alignment tools, SHRiMP, into the cloud environment based on the MapReduce programming model. Critical to the function and performance of our methodology is the implementation of several techniques and mechanisms for facilitating the task of porting the SHRiMP sequence alignment tool into the cloud. These techniques and mechanisms allow the "cloudified" SHRiMP to run as a black box within the MapReduce model, without the need for building new parallel algorithms or recoding this tool from scratch. The approach is based on the MapReduce parallel programming model, its open source implementation Hadoop, and its underlying distributed file system (HDFS). The deployment of the developed methodology utilizes the cloud infrastructure installed at Qatar University. Experimental results demonstrate that multiplexing large-scale SHRiMP sequence alignment jobs in parallel using the MapReduce framework dramatically improves the performance when the user utilizes the resources provided by the cloud. In conclusion, using cloud computing for NGS data analysis is a viable and efficient alternative to analyzing data on in-house compute clusters. The efficiency and flexibility of the cloud computing environments and the MapReduce programming model provide a powerful version of the SHRiMP sequence alignment tool with a considerable boost. Using this methodology, ordinary biologists can perform the computationally demanding sequence alignment tasks without the need to delve deep into server and database management, without the complexities and hassles of running jobs on grids and clusters, and without the need to modify the existing code in order to adapt it for parallel processing.
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Incremental pseudo-conceptual organization of information relative to a domain
المؤلفون: Sahar Ismail and Ali JaouaInformation resources over the World Wide Web are increasingly growing in size and creating immense demand for relevant and context-sensitive information. Thus, information retrieval and knowledge management systems need to exhibit high capacity for the mass of information available and most importantly should be able to handle the constant and rapid changes in information in order to produce results in a reasonable time. In this presentation we would like to highlight the research work done for building a new system for incremental information management relative to a domain of knowledge. The new system (named IPS) utilizes new conceptual methods developed using new formal concept analysis constructs called pseudo concepts for managing incremental information organization and structuring in a dynamic environment. The research work in hand focuses on managing changes in an information store relevant to a specific domain of knowledge attempted through addition and deletion of information. The incremental methods developed in this work should support scalability in change-prone information stores and be capable of producing updates to end users in an efficient time. We will also discuss practical aspects related to the macro and micro information organization built using the new system. These include handling incremental corpus organization for a specific domain, performing context-sensitive text summarization of news articles and news articles features extraction. In addition, initial evaluation results will be also discussed showing the improvement in execution time and time complexity while maintaining reasonable comparable quality of incremental structures produced.
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Binary consensus in sensor motes
المؤلفون: Noor Al-Nakhala, Abderrazak Abdaoui, Ryan Riley and Tarek El-FoulyBackground and Objectives: In this work, we explore the implementation of the binary consensus algorithm in wireless sensor networks. Binary consensus is used to allow a collection of distributed entities to reach consensus regarding the answer to a binary question. Existing work on the algorithm focuses on simulation of the algorithm under the assumption of a fully connected network topology and unlimited messaging capabilities. In this new work, we adapt the algorithm to function in wireless sensor networks where the topology might not be fully connected and the number of messages sent should be minimized in order to save power. Methods: We are deploying and testing our implementation in a hardware embedded systems, mainly IRIS Motes. Our implementation of the binary consensus algorithm is written in NesC and runs on the Tiny Operating System (TinyOS). The implementation was tested on 11 sensor nodes, with current plans to test it on far more. Results: To support our hardware implementation results, a simulation using the Tiny Operating System SIMulator (TOSSIM) was done. Our results in hardware implementation and simulation are consistent with the original binary consensus algorithm. Conclusion: In this work, we adapted the binary consensus algorithm for use in wireless sensor networks. Our implementation for a small number of IRIS motes shows correct results consistent with those of simulation. In future work we will evaluate the effectiveness of the algorithm when scaled to hundreds of sensor motes.
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Qatar Carbonates and Carbon Storage Research Centre: Status update after three years of fundamental research
المؤلفون: Iain Macdonald and Geoffrey MaitlandThere are still specific areas where our knowledge of carbon storage is in need of improvement, particularly in carbonate reservoirs, since currently we extrapolate data from limited sources and the predictive modelling technologies employed have a level of uncertainty that needs to be addressed. We will highlight our efforts through the Qatar Carbonates and Carbon Storage Research Centre (a $70 million, 10 year research programme with currently 20 PhD students and 10 postdoctoral researchers along with 14 faculty members) to investigate the underlying science and engineering concerning carbonate reservoir characterisation, rock-fluid-CO₂ interactions and multiphase flow experiments under reservoir conditions linked to complimentary simulation and modelling advances, including the rapidly developing field of digital rocks. This has involved developing unique HTHP experimental rigs and pioneering new modelling techniques, enhancing the toolbox available to engineers and geoscientists to select suitable reservoirs and optimally design CO₂ storage processes. These capabilities extend over molecular-pore-core-field scales. We have four focused research laboratories (Qatar Stable Isotope Lab; Qatar Thermophysical Property Lab; Qatar Complex Fluids Lab; Qatar CCS Multiscale Imaging Lab) and will discuss the highlights of major research findings to date in the context of carbon storage in the Middle East.
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Artificial ground water recharge using treated wastewater effluents
المؤلفون: Mohamed Hamoda, Mohamed Daerish and Rabi MohtarWater-related problems are increasingly recognized as one of the most immediate and serious environmental threats to mankind. In particular, all the GCC countries being located in an arid region, suffer from lack of natural freshwater resources. Groundwater is the major source of water for irrigation in these countries. The groundwater aquifers contain either fresh or brackish waters. In countries like Kuwait and Qatar the groundwater available is mostly brackish. Agricultural development has put great pressure on groundwater resources and resulted in varying degrees of depletion and contamination as the demand for water has been increasing due to population growth and economic development. Over-pumping of groundwater has compounded water quality degradation caused by salts and other pollutants. In addition, saltwater intrusion is caused by over-abstraction of coastal aquifers. Meanwhile, the GCC countries are also facing changes in climatic conditions, such as rainfall patterns which affect the water cycle and limit natural groundwater recharge. The states of Kuwait and Qatar share almost similar problems and adopt the same approach in the management of their water resources under a severe stress of absence of natural freshwater resources. In these countries, wastewater collection serves almost all the population and tertiary wastewater treatment has been the common practice. Treated wastewater reuse is considered with proper attention to sanitation, public health and environmental protection. This paper will present a detailed evaluation of groundwater recharge using tertiary-treated or advanced (reverse osmosis) -treated wastewater. Recent advances, challenges, and future arrangements are discussed. A case study in Kuwait and an ongoing study in Qatar will be presented which includes advanced wastewater treatment comprising ultrafiltration and reverse osmosis systems, followed by the artificial recharge of the treated water into a groundwater lens. A simulation model is developed based on hydrogeological studies in which the augmentation of groundwater resources would provide water storage, and prevent depletion and deterioration of the groundwater. Hence, long-term sustainable groundwater management could be achieved.
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Breakthrough coastal research of Qatar as input to geological and reservoir modeling
المؤلفون: Sabla Y Alnouri and Patrick LinkeMaximizing recovery in oil and gas fields relies on geological models that realistically portray the spatial complexity, composition, and properties of reservoir units. Present day arid climate coastal systems, like the coastline of Qatar provide analogues for depositional and diagenetic processes that control reservoir quality in ancient reservoirs. Many major reservoirs in Qatar are formed under conditions that are remarkably similar to those shaping the coastlines of today. Among the major controls on coastal sedimentation patterns are: 1) wind, wave and tidal energy, 2) coastline orientation, 3) relative sea level, 4) depositional relief and 5) sediment sources. Strong NW prevailing winds (shamal winds) drive shallow marine circulation patterns, creating four very distinct coastal profiles: windward, leeward, oblique, and protected. In addition, winds supply quartz sand to the leeward coast, as the dune fields of Khor Al-Adaid are blown into the sea. Elsewhere, carbonate sands are formed by wave breakdown of skeletal material in the shallow marine environment. These sands are washed ashore to form beaches. The grain size, composition, and dimensions of coastal sands vary due to wave energy. Coastal deposits are equally affected by high frequency oscillations in sea level. Approximately 8,000 years ago, the sea level was about 3 meters higher than it is currently and the Qatari coastline was up to 15 km inland. Most coastal deposits and sabkhas are relicts of this ancient highstand in sea level. Punctuated sea level drops to present day levels have led to the formation of seaward-stepping spit systems. Understanding these coastal and near coastal areas, the processes that form them, and developing geologic models based on this understanding, is a focus of the Qatar Center for Coastal Research (QCCR) within ExxonMobil Research Qatar. The observed spatial complexity and heterogeneity of modern coastal systems are important aspects to be considered for conditioning three-dimensional geological models. The studied modern outcrops along the Qatar coastline are particularly useful as analogs for conditioning subsurface data sets in geologic (static) and reservoir (dynamic) models.
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