Performance of some man-machine systems at Iowa State University Farm Service

The United States of America is recognized as one of the largest producers of food and fiber in the world. The application of machines to the agricultural production has been a major factor of the outstanding developments in American agriculture during the past century. The continuous improvement of farm machinery contributed to the increase of the United States agricultural production while releasing millions of agricultural workers to other industries. Today the farm population of the United States accounts for only 3.8% of the total population (USDA Agricultural Statistics, 1978)

Performance Modelling and Optimisation of Multi-hop Networks

A major challenge in the design of large-scale networks is to predict and optimise the total time and energy consumption required to deliver a packet from a source node to a destination node. Examples of such complex networks include wireless ad hoc and sensor networks which need to deal with the effects of node mobility, routing inaccuracies, higher packet loss rates, limited or time-varying effective bandwidth, energy constraints, and the computational limitations of the nodes. They also include more reliable communication environments, such as wired networks, that are susceptible to random failures, security threats and malicious behaviours which compromise their quality of service (QoS) guarantees. In such networks, packets traverse a number of hops that cannot be determined in advance and encounter non-homogeneous network conditions that have been largely ignored in the literature. This thesis examines analytical properties of packet travel in large networks and investigates the implications of some packet coding techniques on both QoS and resource utilisation. Specifically, we use a mixed jump and diffusion model to represent packet traversal through large networks. The model accounts for network non-homogeneity regarding routing and the loss rate that a packet experiences as it passes successive segments of a source to destination route. A mixed analytical-numerical method is developed to compute the average packet travel time and the energy it consumes. The model is able to capture the effects of increased loss rate in areas remote from the source and destination, variable rate of advancement towards destination over the route, as well as of defending against malicious packets within a certain distance from the destination. We then consider sending multiple coded packets that follow independent paths to the destination node so as to mitigate the effects of losses and routing inaccuracies. We study a homogeneous medium and obtain the time-dependent properties of the packet’s travel process, allowing us to compare the merits and limitations of coding, both in terms of delivery times and energy efficiency. Finally, we propose models that can assist in the analysis and optimisation of the performance of inter-flow network coding (NC). We analyse two queueing models for a router that carries out NC, in addition to its standard packet routing function. The approach is extended to the study of multiple hops, which leads to an optimisation problem that characterises the optimal time that packets should be held back in a router, waiting for coding opportunities to arise, so that the total packet end-to-end delay is minimised

Regional marriage patterns and trends in Northern Sudan

Marriage is an important institution for both individuals and society as a whole. It is a significant event in the life cycle of individuals; for society at large it represents the creation of a new unit of production, consumption, distribution and exchange of goods and services. In most comparative studies of nuptiality it has been usual to characterize sub-Saharan pattern of marriage as “early and universal”. Early and virtually continuous marriage throughout a woman\u27s reproductive years is also maintained by several related marriage customs including polygyny, levirate marriage, and bride wealth or bride price (van de Walle, 1968;Goldman and Pebley, 1986)

Effect of Feeding Frequency and Stocking Density on Tilapia Oreochromis Niloticus and Lettuce Lactuca Sativa Production in Aquaponics System under the UAE Condition and Business Enterprise Analysis

This thesis was carried out to investigate the impact of various Tilapia (Oreochromisniloticus) feeding frequency and stocking density on quality and quantity of organic lettuce that is produced in an aquaponic system, knowing that they affect the nutrient content in water. Business analysis through enterprise budget was developed considering different feeding frequency and stocking density of the fish to predict the business efficiency of the system, and the net incomes were as high as AED 34,394 and AED 46,637, respectively. On the other hand, lettuce was seeded in a culture raceway. The duration of the experiments was decided to be six months, which was divided into two parts to study each parameter, i.e. feeding frequency (Once, twice and three times per day) and stocking density (100,120,140 fishes per cubic meter). In parallel, the aquaponic system water quality (pH, temperature, total dissolved solids, dissolved Oxygen, total ammonia, nitrite, and nitrate) and water consumption were analyzed at specified intervals. Furthermore, fish and cultivated plant growth rate and total yield were analyzed at the first and last days of the experimental period. The purpose of that was to optimize the system feeding system and stocking from different approaches both agriculturally and economically. It was found that highest used feeding frequency and stocking density are recommended to achieve high profitabilit

Utilizing Steel Slag in the Removal of Suspended Solids from Dewatered Construction Water: A Mechanistic Study

Construction dewatering is an operation used to remove shallow groundwater infiltrated into a construction site; this technique is used in most of the construction projects. After collecting the water from the construction site, the water is either discharged to the sea, injected in deep groundwater aquifers, or treated and reused in some other applications. In this study, treatment of dewatered construction water by waste steel slag was performed. The impact of the mass of steel slag, the contact time, steel slag particle size and pH were studied on the quality of dewatered construction water. It was found that the maximum removal percentage of suspended solids was 97%, which occurred when 5 grams of steel slag were in contact with the dewatered construction water. The uptake amount (q) was 63.12 mg of suspended solid per gram of steel slag. It was observed that equilibrium was achieved after a contact time of about 40 minutes. The impact of steel slag particle size was studied, where two different sizes of steel slag particles were considered namely, 425 and 75 nm. An uptake value (q) of 72.24 mg/g and 64.36 mg/g were obtained for steel slag particle size 425 nm and 75 nm, respectively. The impact of pH was studied, where it was found that at pH value of 12, the removal percentage of suspended solids was higher than pH of 2, where the uptake amount of suspended solids was 80 mg/g. In addition, the performance of steel slag was compared to a commercial chemical coagulant, where steel slag had a higher uptake amount of 72.24 mg/g compared to 60.62 mg/g for the commercial coagulant

Kinetics of ketone hydrogenation over supported Ru catalysts

A kinetic investigation of the production of y-valerolactone (GVL) via the aqueous phase hydrogenation of levulinic acid (LA) over supported Ru catalysts was carried out, in order to understand how to better design a hydrogenation catalyst for such biomass catalytic strategies. At temperatures representative of biomass processing, the reaction proceeds first through the reduction of the LA ketone group to its corresponding alcohol, 4-hydroxypentanoic acid (HPA), which subsequently produces GVL via intramolecular esterification in solution. The governing kinetics of LA hydrogenation were found to be insensitive to the identity of the support material on which Ru catalysts were prepared. Conversely the stability of supported Ru catalysts in the aqueous phase were strongly dependent on the choice of support, exhibiting severe sintering of Ru nanoparticles, the extent of which appears to be dictated by the bulk electronegative properties of the support material. The presence of a secondary functional group in LA (i.e., a carboxyl group) does not appear to perturb the activity of Ru sites in water, where LA and its mono-functional ketone analog (2-pentanone) hydrogenate at identical rates. LA hydrogenation thus appears kinetically equivalent to that of 2-pentanone. Given the similarity, C3-C5 ketone hydrogenation over Ru/SiO2 in the vapor-phase was examined, alleviating the need to consider solution phase complexities. A single universal microkinetic model for the hydrogenation of ketones over supported Ru catalysts was developed, based on a modified Horiuti-Polanyi-type mechanism involving two distinct surface sites. Through the application of surface lateral interactions to the developed ketone microkinetic model, solvent effects commonly reported for hydrogenations over Ru catalysts are rationalized on the basis of the stabilization of a kinetically relevant transition state

REGION-BASED ADAPTIVE DISTRIBUTED VIDEO CODING CODEC

The recently developed Distributed Video Coding (DVC) is typically suitable for the applications where the conventional video coding is not feasible because of its inherent high-complexity encoding. Examples include video surveillance usmg wireless/wired video sensor network and applications using mobile cameras etc. With DVC, the complexity is shifted from the encoder to the decoder. The practical application of DVC is referred to as Wyner-Ziv video coding (WZ) where an estimate of the original frame called "side information" is generated using motion compensation at the decoder. The compression is achieved by sending only that extra information that is needed to correct this estimation. An error-correcting code is used with the assumption that the estimate is a noisy version of the original frame and the rate needed is certain amount of the parity bits. The side information is assumed to have become available at the decoder through a virtual channel. Due to the limitation of compensation method, the predicted frame, or the side information, is expected to have varying degrees of success. These limitations stem from locationspecific non-stationary estimation noise. In order to avoid these, the conventional video coders, like MPEG, make use of frame partitioning to allocate optimum coder for each partition and hence achieve better rate-distortion performance. The same, however, has not been used in DVC as it increases the encoder complexity. This work proposes partitioning the considered frame into many coding units (region) where each unit is encoded differently. This partitioning is, however, done at the decoder while generating the side-information and the region map is sent over to encoder at very little rate penalty. The partitioning allows allocation of appropriate DVC coding parameters (virtual channel, rate, and quantizer) to each region. The resulting regions map is compressed by employing quadtree algorithm and communicated to the encoder via the feedback channel. The rate control in DVC is performed by channel coding techniques (turbo codes, LDPC, etc.). The performance of the channel code depends heavily on the accuracy of virtual channel model that models estimation error for each region. In this work, a turbo code has been used and an adaptive WZ DVC is designed both in transform domain and in pixel domain. The transform domain WZ video coding (TDWZ) has distinct superior performance as compared to the normal Pixel Domain Wyner-Ziv (PDWZ), since it exploits the ' spatial redundancy during the encoding. The performance evaluations show that the proposed system is superior to the existing distributed video coding solutions. Although the, proposed system requires extra bits representing the "regions map" to be transmitted, fuut still the rate gain is noticeable and it outperforms the state-of-the-art frame based DVC by 0.6-1.9 dB. The feedback channel (FC) has the role to adapt the bit rate to the changing ' statistics between the side infonmation and the frame to be encoded. In the unidirectional scenario, the encoder must perform the rate control. To correctly estimate the rate, the encoder must calculate typical side information. However, the rate cannot be exactly calculated at the encoder, instead it can only be estimated. This work also prbposes a feedback-free region-based adaptive DVC solution in pixel domain based on machine learning approach to estimate the side information. Although the performance evaluations show rate-penalty but it is acceptable considering the simplicity of the proposed algorithm. vii

Compositional structures in mural design : towards a site-specific deconstructive mural methodology

A thesis submitted to the University of Bedfordshire in partial fulfilment of the requirements of the degree of Doctor of Philosophy (PhD)Murals have been the formal visual interpretation of the cultural, social and political life of all ages. Throughout they have been consistently combined with their architectural setting, for example, in ancient Egyptian tombs, in Renaissance churches and on the external walls of buildings in Mexico in the twentieth century. This is a central feature of mural painting. However many contemporary murals do not integrate with their architectural settings, in other words, do not fulfil the site-specificity of the architectural spaces for which they were made. This means that the most important aspect that distinguishes murals from other types of painting is absent. I studied and analysed a number of murals produced in the Italian Renaissance, Baroque and Rococo as this particular period is considered to be not only one of the most significant in the history of art but also a period in which painting and architecture were very closely allied as practices. In particular the radical developments in painting of pictorial space took place along side the developments in architecture. I argue that Renaissance murals could be described, using the terminology of contemporary art, as site-specific art. By identifying the relationship between pictorial space, architectural space and compositional structure I was able to test, through my own practice, the importance of these relationships in understanding the site-specificity of the compositional structure of murals. To address the issue of sitespecificity in murals, I investigated and developed a set of compositional structures through my mural practice that could be applied in the design, execution, and teaching of contemporary mural design. I have developed the notion of a deconstructive method of mural design in which the illusory space of the mural derives its compositional structure from the architectural space in which it sited. I have applied it, tested it and refined it through the execution of a number of hypothetical and live mural commissions. I believe that the approach to the study and practice of mural design I have developed from the perspective of a practice lead researcher contributes to the furtherance of mural design as both a profession and field of study. In particular the identification of compositional structures in mural design and the proposal of a deconstructive method contributes to our understanding of what a mural is as well as current notions of site-specificity in contemporary art

Process Planning for Assembly and Hybrid Manufacturing in Smart Environments

Manufacturers strive for efficiently managing the consequences arising from the product proliferation during the entire product life cycle. New manufacturing trends such as smart manufacturing (Industry 4.0) present a substantial opportunity for managing variety. The main objective of this research is to help the manufacturers with handling the challenges arising from the product variety by utilizing the technological advances of the new manufacturing trends. This research focuses mainly on the process planning phase. This research aims at developing novel process planning methods for utilizing the technological advances accompanied by the new manufacturing trends such as smart manufacturing (Industry 4.0) in order to manage the product variety. The research has successfully addressed the macro process planning of a product family for two manufacturing domains: assembly and hybrid manufacturing. A new approach was introduced for assembly sequencing based on the notion of soft-wired galled networks used in evolutionary studies in Biological and phylogenetic sciences. A knowledge discovery model was presented by exploiting the assembly sequence data records of the legacy products in order to extract the embedded knowledge in such data and use it to speed up the assembly sequence planning. The new approach has the capability to overcome the critical limitation of assembly sequence retrieval methods that are not able to capture more than one assembly sequence for a given product. A novel genetic algorithm-based model was developed for that purpose. The extracted assembly sequence network is representing alternative assembly sequences. These alternative assembly sequences can be used by a smart system in which its components are connected together through a wireless sensor network to allow a smart material handling system to change its routing in case any disruptions happened. A novel concept in the field of product variety management by generating product family platforms and process plans for customization into different product variants utilizing additive and subtractive processes is introduced for the first time. A new mathematical programming optimization model is proposed. The model objective is to provide the optimum selection of features that can form a single product platform and the processes needed to customize this platform into different product variants that fall within the same product family, taking into consideration combining additive and subtractive manufacturing. For multi-platform and their associated process plans, a phylogenetic median-joining network algorithm based model is used that can be utilized in case of the demand and the costs are unknown. Furthermore, a novel genetic algorithm-based model is developed for generating multi-platform, and their associated process plans in case of the demand and the costs are known. The model\u27s objective is to minimize the total manufacturing cost. The developed models were applied on examples of real products for demonstration and validation. Moreover, comparisons with related existing methods were conducted to demonstrate the superiority of the developed models. The outcomes of this research provide efficient and easy to implement process planning for managing product variety benefiting from the advances in the technology of the new manufacturing trends. The developed models and methods present a package of variety management solutions that can significantly support manufacturers at the process planning stage

Perceptions of Egyptian ESL teachers of teaching aspects of the target culture: The case of culturally-oriented speech acts in textbooks

The study explores issues related to the place of the target culture in the context of teaching English as a foreign/second language in Egypt. There are two research questions in this study. The first one is concerned with identifying the speech acts taught in the Hello! textbook studied by Egyptian students in all governmental and private schools of the third year of General Secondary Education. The second research question investigated the perceptions of governmental and private school teachers on teaching aspects of the target culture in their English classes in Egyptian schools. The research is of a quantitative/qualitative nature. A critical analysis of the speech acts activities from the Hello! textbook has been provided and it was found that only six units out of 18 in the Hello! textbook contain information on speech acts. These six speech acts are: giving advice, making and responding to suggestions, expressing wishes and regrets, offer to help, giving and responding to warnings, and persuading. Using a teacher questionnaire, data from 50 participants teaching at governmental and private schools in Egypt has been collected. This data was supplemented by interviews with three teachers from each type of school for a total of six teachers. The results reported from the questionnaire are in the form of statistics while those reported from the interviews are in the form of descriptive analysis. The results of the study show that the teaching of the target culture and pragmatics in ESL classes in Egypt is neglected due to many reasons, which include the lack of facilities and resources available to teachers, the use of a standardized high school exit exam which does not include questions on cultural aspects, and the resultant washback effect on teachers\u27 and students\u27 attitude toward the inutility of teaching cultural aspects