MAC/Routing design for under water sensor networks

The huge advances in communication technologies and Micro Electrical and Mechanical Systems (MEMS) have triggered a revolution in sensor networks. One major application of sensor networks is in the investigation of complex and uninhabited under water surfaces; such sensor networks are called the Underwater Wireless Sensor Networks (UWSN). UWSN comprises of a number of sensors which are submerged in water and one or several surface stations or a sinks at which the sensed data is collected. In some underwater sensor applications, autonomous underwater vehicles (AUVs) could be used. The underwater sensor nodes communicate with each other using acoustic signals. Applications for this type of networks include oceanographic data collection, pollution monitoring, offshore exploration and tactical surveillance applications. The novel networking paradigm of UWSN is facing a totally different operating environment than the ground based wireless sensor networks. This introduces new challenges such as huge propagation delays, and limited acoustic link capacity with high attenuation factors. These new challenges have their own impact on the design of most of the networking layers preventing researchers from using the same layers used for other networks. The most affected layers are the Physical, Medium Access Control (MAC), Routing and Transport layers. This work will introduce novel routing and MAC layers’ protocols for UWSNs. The routing protocol will adopt the minimum spanning tree algorithm and focus on maximizing the connectivity of the network, which means maximizing the total number of nodes connected to the root or the sink in this case. The protocol will try also to provide a minimum hop connection for all the nodes in the network taking into account the residual energy, location information and number of children at the next hop node. The other contribution of this work is a MAC Protocol which will incorporate the topology information provided by the routing protocol to minimize the collisions and energy wastage in data transmission. The MAC Protocol will also try to shorten the queuing delays at the intermediate nodes for a message traveling from source to the sink. A comparison will be conducted with other existing routing and MAC protocols. The routing protocol will be tested and compared with the E-Span spanning tree algorithm for data aggregation. The MAC protocol will be compared with Park\u27s protocol proposed in [2] in terms of performance metrics like end-to-end delay and the number of collisions. We will also explore the ability of the proposed protocols to enhance the life span of the network

Hydrophilic Acrylic versus Polymethylmethacrylate Intraocular Lens Implantation for Pediatric Cataract Surgery: Iraqi Study

الغرض لعمل دراسة و مقارنة بين الزرع الابتدائي للعدسة  الأكرليك المطوية والعدسة الصلبة داخل العين لجراحة الماء الابيض للاطفال فيما يتعلق بالنتائج البصرية والمضاعفات . طريقة العمل دراسة سريرية شملت 40 عيناً لـ 31 مريضا تتراوح اعمارهم ما بين سنة الى ست سنوات كانو يعانون من الماء الابيض لعين واحدة او لكلتا العينين سواء كان ولاديا او مكتسبا .هناك نوعان من العدسات تم استخدامهما : المطوية والصلبة حيث  ان عملية فتح محفظة العين الامامية وعملية قص السائل الزجاجي الامامي تم اجراؤها في جميع المرضى و بعد اجراء الجراحة تمت متابعة المرضى  لمدة عام كامل . النتائج في هذه الدراسة كان متوسط عمر الاطفال لمجموعة العدسات المطوية 3.2 سنة  ولمجموعة العدسات الصلبة 3.7 ومعدل متابعة المريض بعد العملية 19.6 شهرا  (12-29) وفيما يخص المضاعفات فان المضاعفات اثناء اجراء العملية الجراحية لم تحدث اما ما يتعلق بالمضاعفات بعد العملية فان التهاب القزحية تم ملاحظته بنسبة 2% من اطفال مجموعة العدسات المطوية بينما 25% من اطفال مجموعة العدسات الصلبة. ومن المضاعفات الاخرى التي تم ملاحظتها من خلال المتابعة: تصبغ القرنية 30% والتصاقات القرنية الخلفية 10% والتصاقات القرنية بالقزحية 10% وهذه المضاعفات تم مشاهدتها بالعدسات الصلبة فقط اما بالنسبة للنتائج البصرية فقد كانت جيدة بشكل عام. الاستنتاج الاطفال الذين خضعوا لعملية رفع العدسة و عملية فتح محفظة العين الامامية وعملية قص السائل الزجاجي الخلفية تمت مقارنة النتائج البصرية والمضاعفات بين العدسات المستخدمة لهم (المطوية و الصلبة) وقد وجد خلال الدراسة ان العدسة المطوية افضل بالنتائج واقل مضاعفات.Purpose To make a comparison between the primary implantation of the foldable hydrophilic acrylic and the polymethylmethacrylate intraocular lenses of pediatric cataract surgery that generally includes short term complications and visual results. Methods This clinical study includes 40 eyes of 31 consecutive patients who aged from 1 to 6 years complaining from unilateral or bilateral, congenital or developmental cataracts. Two kinds of IOLs, including foldable hydrophilic acrylic and PMMA were randomly implanted in the capsular bag during surgery. Primary posterior capsulotomy and anterior vitrectomy were performed in all eyes. Patients were followed up for at least 1 year. Perioperative complications, visual results and refractive errors were compared between the study categories. Results In the study, regarding age, it was 3.2±1.8 years of the hydrophilic acrylic group and 3.7±1.3 years of the PMMA group. Regarding follow up mean period was 19.6±5 (12–28) months. Intraoperative complications don’t occurr in any group. Postoperative uveitis was observed in 2 (10%) eyes in the acrylic group patient versus 5 (25%) eyes in the PMMA group patient (P=0.40). Other postoperative complications include pigment deposition (30%), posterior synechiae formation (10%) and iridocorneal adhesions (10%), were observed only in the PMMA group. Visual outcomes in these groups study were good and comparable and the visual axis was completely clear Conclusion In pediatric eyes in whom lensectomy was doing with the primary posterior capsulotomy and anterior vitrectomy, the comparison between the hydrophilic acrylic IOLs and PMMA IOLs was made including biocompatibility and visual axis. The observation was that hydrophilic acrylic IOLs is less frequent postoperative complications

The Impact of Adaptation Delays on Routing Protocols forMobile Ad-Hoc Networks (MANETs)

MANETs are coping with major challenges such as the lack of infrastructure and mobility which causes networks topology to change dynamically. Due to limited resources, nodes have to collaborate and rely packets on the behalf of neighbors to reach their destinations forming multi-hop paths. The selection and maintenance of multi-hop paths is a challenging task as their stability and availability depend on the mobility of participating nodes, where paths used a few moments earlier would be rendered invalid due to ever changing topology. The purpose of a routing protocol is to establish and select valid paths between communicating nodes and repair or remove invalid ones. As mobility rate increases, routing protocols spend more time in path maintenance and less time in actual data communication, degrading network performance. This interaction among mobility, topology and routing performance is usually empirically studied through simulations. This dissertation will provide a novel deep analytical study of the root cause of performance degradation with mobility. This is accomplished by, firstly, studying how mobility impacts durations of topology paths called Topological modeling. Secondly, analyzing how routing protocols adapt to topology changes in Adaptability modeling which identifies AdaptationDelays representing the time taken by a routing protocol to translate a change in topology to logical information used in path selection. Combining the results from these two studies, performance models of routing protocols are obtained, which later is used to optimize its operation. This study is applied on two tree-based proactive routing protocols, the Optimized Link State Routing and the Multi-Meshed Tree

Removal of various aromatic compounds from synthetic and refinery wastewater using soybean peroxidase

Crude soybean peroxidase (SBP), isolated from soybean seed hulls, catalyzed the oxidative polymerization of hazardous aqueous pollutant aryldiamines, aryldiols, 2-mercaptobenzothiazole and phenol in the presence of hydrogen peroxide. Experiments were conducted to investigate the optimum operating conditions including pH, hydrogen peroxide-to-substrate concentration ratio and the minimum SBP concentration required to achieve at least 95 conversion of these pollutants in synthetic and refinery wastewaters. In addition, the effect of PEG3350 on enhancing the conversion efficiency was studied. The substrate conversion and hydrogen peroxide consumption were monitored over the period of the reactions. The enzymatically-generated polymeric products from aryldiamines could be removed with surfactant, sodium dodecyl sulphate (SDS), whereas polyvalent metal cation salt, aluminium sulphate (Alum), was able to remove the products from aryldiols. Enzyme-catalyzed polymerization using SBP and the methods for removal of the generated polymeric products can provide an alternative means to the conventional treatment methods for treating aromatic wastewater pollutants

Studies on the Odonata and Trichoptera of high-elevation lakes of northern Colorado and southern Wyoming

2021 Fall.Includes bibliographical references.Freshwater biodiversity loss is a major concern, and global warming is already causing a significant role in species extinctions. The main goal of this research was to provide a baseline for specific aquatic insect species distributions at high-elevation lentic habitats in Northcentral Colorado and Southern Wyoming. I provided occurrence records of the Hudsonian Emerald dragonfly (Somatochlora hudsonica, HED) in Northcentral Colorado and Southern Wyoming. The HED is the only Colorado dragonfly listed as threatened by the US Forest Service. It was ranked as critically imperiled in Colorado and vulnerable in Wyoming. I used Maxent (Maximum entropy), a machine learning program that uses species presence data and environmental variables to predict the potentially suitable habitat for species. Maxent was used to plot a map of the potentially suitable habitats of HED. Temperature seasonality, mean temperature of wettest quarter, precipitation of warmest quarter, precipitation of driest quarter, and precipitation seasonality were the key environmental factors for predicting the occurrence of HED in appropriate high-elevation lakes of Northcentral Colorado and Southern Wyoming with an accumulated contribution of 91%. Results of this study provided baseline data for the US Forest Service to assist to evaluate the conservation status of HED and potentially initiate protection plans in two national forests (The Arapaho & Roosevelt National Forest and the Medicine Bow & Routt National Forest) in Colorado and Wyoming. I report adult caddisflies from 136 montane and alpine lentic habitats, primarily lakes, of seven northern Colorado counties for the first time. My objective was to provide species records of adult and larval caddisflies from high-altitude lentic habitats that are not generally well sampled. These lakes may be potentially impacted by current and future global climate change scenarios. Field collection of adults and rearing of larvae were included with available unpublished and published records, resulting in 541 confirmed records of caddisfly species. Forty-nine species, representing 24% of all known Colorado caddisflies are documented. Seven families and 24 genera are represented. The Limnephilidae comprised 76% of the 49 recorded species. The other six families were usually represented by only one to four species. Distribution maps are presented for the six families and the most common limnephilid species. Montane and alpine lakes are vulnerable ecosystems likely to be impacted by climate change. Comprehensive faunal surveys are key to understanding long–term biodiversity changes and establishing conservation needs and priorities. In addition, species lists of taxa are important to monitor future faunal biodiversity changes

Using of Video Modeling in Teaching a Simple Meal Preparation Skill for Pupils of Down Syndrome

The current study aimed to identify the impact of video modeling upon teaching three pupils with Down syndrome the skill of preparing a simple meal (sandwich), where the training was conducted in a separate classroom in schools of normal students. The training consisted of (i) watching the video of an intellectually disabled pupil, who is preparing a sandwich of cream cheese; (ii) receiving verbal praise for each step of the training that was performed correctly. The results showed that the pupils mastered the skill of preparing sandwich independently, the skill generalization has been verified and the pupils demonstrated maintenance of the skill 14 days following mastery. Keywords: Dawn syndrome, video modeling, daily living skill

Quality of media traffic over Lossy internet protocol networks: Measurement and improvement.

Voice over Internet Protocol (VoIP) is an active area of research in the world of communication. The high revenue made by the telecommunication companies is a motivation to develop solutions that transmit voice over other media rather than the traditional, circuit switching network. However, while IP networks can carry data traffic very well due to their besteffort nature, they are not designed to carry real-time applications such as voice. As such several degradations can happen to the speech signal before it reaches its destination. Therefore, it is important for legal, commercial, and technical reasons to measure the quality of VoIP applications accurately and non-intrusively. Several methods were proposed to measure the speech quality: some of these methods are subjective, others are intrusive-based while others are non-intrusive. One of the non-intrusive methods for measuring the speech quality is the E-model standardised by the International Telecommunication Union-Telecommunication Standardisation Sector (ITU-T). Although the E-model is a non-intrusive method for measuring the speech quality, but it depends on the time-consuming, expensive and hard to conduct subjective tests to calibrate its parameters, consequently it is applicable to a limited number of conditions and speech coders. Also, it is less accurate than the intrusive methods such as Perceptual Evaluation of Speech Quality (PESQ) because it does not consider the contents of the received signal. In this thesis an approach to extend the E-model based on PESQ is proposed. Using this method the E-model can be extended to new network conditions and applied to new speech coders without the need for the subjective tests. The modified E-model calibrated using PESQ is compared with the E-model calibrated using i ii subjective tests to prove its effectiveness. During the above extension the relation between quality estimation using the E-model and PESQ is investigated and a correction formula is proposed to correct the deviation in speech quality estimation. Another extension to the E-model to improve its accuracy in comparison with the PESQ looks into the content of the degraded signal and classifies packet loss into either Voiced or Unvoiced based on the received surrounding packets. The accuracy of the proposed method is evaluated by comparing the estimation of the new method that takes packet class into consideration with the measurement provided by PESQ as a more accurate, intrusive method for measuring the speech quality. The above two extensions for quality estimation of the E-model are combined to offer a method for estimating the quality of VoIP applications accurately, nonintrusively without the need for the time-consuming, expensive, and hard to conduct subjective tests. Finally, the applicability of the E-model or the modified E-model in measuring the quality of services in Service Oriented Computing (SOC) is illustrated

Adaptive, reliable, and accurate positioning model for location-based services

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis presents a new strategy in achieving highly reliable and accurate position solutions fulfilling the requirements of Location-Based Services (LBS) pedestrians’ applications. The new strategy is divided into two main parts. The first part integrates the available positioning technology within the surrounding LBS application context by introducing an adaptive LBS framework. The context can be described as a group of factors affecting the application behaviour; this includes environmental states, available resources and user preferences. The proposed adaptive framework consists of several stages, such as defining the contextual factors that have a direct effect on the positioning performance, identifying preliminary positioning performance requirements associated with different LBS application groups, and introducing an intelligent positioning services selection function. The second part of this work involves the design and development of a novel positioning model that is responsible for delivering highly reliable, accurate and precise position solutions to LBS users. This new model is based on the single frequency GPS Standard Positioning Service (SPS). Additionally, it is incorporated within the adaptive LBS framework while providing the position solutions, in which all identified contextual factors and application requirements are accounted. The positioning model operates over a client-server architecture including two main components, described as the Localisation Server (LS) and the Mobile Unit (MU). Hybrid functional approaches were developed at both components consisting of several processing procedures allowing the positioning model to operate in two position determination modes. Stand-alone mode is used if enough navigation information was available at the MU using its local positioning device (GPS/EGNOS receiver). Otherwise, server-based mode is utilised, in which the LS intervenes and starts providing the required position solutions. At the LS, multiple sources of GPS augmentation services were received using the Internet as the sole augmentation data transportation medium. The augmentation data was then processed and integrated for the purpose of guaranteeing the availability of valid and reliable information required for the provision of accurate and precise position solutions. Two main advanced position computation methods were developed at the LS, described as coordinate domain and raw domain. The positioning model was experimentally evaluated. According to the reported results, the LS through the developed position computation methods, was able to provide position samples with an accuracy of less than 2 meters, with high precision at 95% confidence level; this was achieved in urban, rural, and open space (clear satellite view) navigation environments. Additionally, the integrity of the position solutions was guaranteed in such environments during more than 90% of the navigation time, taking into consideration the identified integrity thresholds (Horizontal Alert Limits (HAL)=11 m). This positioning performance has outperformed the existing GPS/EGNOS service which was implemented at the MU in all scenarios and environments. In addition, utilising a simulation evaluation facility the developed positioning model performance was quantified with reference to a hybrid positioning service that will be offered by future Galileo Open Service (OS) along with GPS/EGNOS. Using the statistical t-test, it was concluded that there is no significant difference in terms of the position samples’ accuracy achieved from the developed positioning model and the hybrid system at a particular navigation environment described as rural area. The p-value was 0.08 and the level of significance used was 0.05. However, a significant difference in terms of the service integrity for the advantage of the hybrid system was experienced in all remaining scenarios and environments more especially the urban areas due to surrounding obstacles and conditions