Load Balancing Hotspots in Sensor Storage Systems

Sensor networks provide us with the means of effectively monitoring and interacting with the physical world. A sensor network usually consists of a large number of small inexpensive battery-operated sensors deployed in a geographic area. This dissertation considers a sensor network deployed to monitor a disaster area. First responders continuously issue ad-hoc queries while moving in the disaster area. In such an environment, it is often more beneficial to store sensor readings and process ad-hoc queries within rather than outside the sensor network.Recently, this led to an increased popularity of Data-Centric Storage (DCS).A DCS scheme is based on a mapping function from readings to sensors based on the attribute values of each reading. This mapping function defines the DCS index structure.Two significant problems arising in this DCS network model due to data and traffic skewness are storage hotspots and query hotspots. Storage hotspots are formed when many sensor readings are mapped for storage to a relatively small number of sensor nodes. Query hotspots occur when many user queries target few sensor nodes. Both types of hotspots are hard to predict. Storage hotspots result in an uncontrolled reading shedding that decreases the Quality of Data (QoD). Due to the limited wireless bandwidth of sensors, hotspots decrease QoD by increasing collisions (thus losses) of reading/query packets. When lasting long enough, hotspots affect the Quality of Service (QoS) by unevenly depleting energy in the sensor network.This dissertation addresses both problems of hotspots through load balancing. The main dissertation hypothesis is that data migration resulting from local or global load balancing of the DCS index structure can effectively solve the hotspot problems. The contributions of this dissertation lie in developing two schemes, namely, the Zone Sharing/Zone Partitioning/Zone Partial Replication (ZS/ZP/ZPR) scheme and the K-D tree based Data-Centric Storage (KDDCS) scheme. ZS/ZP/ZPR detects and decomposes both types of hotspots through load balancing in the hotspot area. KDDCS avoids the formation of hotspots through globally load-balancing the underlying DCS index structure. Experimental evaluation shows the effectiveness of the proposed schemes in coping with hotspots in comparison to the state-of-the-art DCS schemes

Novel 4(3H)-quinazolinones containing biologically active thiazole, pyridinone and chromene of expected antitumor and antifungal activities

Novel 4(3H)-quinazolinone derivatives with biologically active moieties were synthesized. Reactions of 2-cyano-N-(6-iodo-2-methyl-4-oxoquinazolin-3(4H)-yl) acetamide with carbon disulfide, isothiocyanates followed by cycloalkylation afforded acrylamide, 1,3-dithiazole, 1,3-dithiane, thiazole and pyrazole derivatives. The 2-pyridone derivatives were obtained via reaction of cyanoacetamide with some acetylacetone or arylidenes. Cyclocondensation reaction of cyanoacetamide with o-hydroxy aldehydes furnished chromene derivatives. Screening for some selected compounds was carried for their potential antitumor and antifungal activities. 2-Cyano-N-(6-iodo-2-methyl-4-oxoquinazolin-3(4H)-yl)-2-(4-methyl-3-phenyl-thiazol-2(3H)ylidene)-acetamide with 3-side chain incorporated with substituted thiazole moiety was found to be of high to moderate activity towards cells. Also, the latter product showed high activity against Aspergillus ochraceus Wilhelm with inhibition zone (18 mm) compared with (20 mm) Nystatin inhibition zone

Chapter 5 Groundwater

This chapter presents an introduction to the basic concepts and developments in the study of flow of water in the subsurface environment. The importance of groundwater as a natural freshwater reserve and for the public health is initially described. The relation between groundwater extraction and land subsidence is discussed, as well as the problems of coastal saltwater intrusion. Subsequently, an exposition is presented of the basic groundwater flow equations that include Darcy\u27s law and the continuity equation. Flow in fractured rocks is briefly discussed together with the cubic law that describes the velocity in such media. The concept of the effective hydraulic conductivity is introduced through the flow in stratified aquifers, followed by the mathematical exposition of one-dimensional (1-D) flow in confined and unconfined aquifers. Applications are provided for the cases of flow through earth dams, aquifers under rain, and groundwater flow to streams. The final part of this chapter introduces some basic concepts and solutions from well hydraulics. Steady-state flow to wells in confined and unconfined aquifer, the method of images, and De Glee\u27s solution for leaky aquifers are presented. The chapter concludes with an exposition of issues related to construction dewatering

Chapter 1 Geoenvironmental Engineering in a Global Environment

The global environmental problems and the demographic problem, which are the focus of the geoenvironmental engineering practice, and the actions toward restoration of the environment are the subjects of this chapter. In seeking solutions to restore the degradation of the environment, we need to consider the interconnecting nature of the various ecosystems and be aware of the developments in various allied disciplines and how these may impact on developing and implementing sound engineering solutions to various environmental problems. The impact of the exploitation and utilization of the natural systems by nations on the depletion of natural resources; elimination of species; flora and fauna local and regional changes; and deterioration of the environment through solid and liquid waste, air and water pollution, and by greenhouse gases is summarized with case studies from around the world. It is also highlighted that the impacts upon the natural systems vary geographically, depending on the existing states of both the natural environment and the economy, but in many cases these impacts extend to a regional or even a global scale. This chapter also discusses evidences of global environmental impacts such as: (a) pollution of air, land, and water, due to accidents during the transportation of oil or other products by ship, plastic debris in the rivers and oceans, effluent discharge into fresh water bodies; (b) water scarcity and degradation; (c) growing quantities of wastes as a result of chemical product utilizations in all human activities, from agriculture to medicine, to energy and industrial and manufacturing processes, to everyday products; (d) trans-boundary movement of hazardous waste; (e) acid rain; (f) deforestation and land degradation; (g) desertification and soil erosion; (h) depletion of the ozone layer; and (i) the decreasing species of wildlife. The greatest emphasis is given here to global warming and climate change, where, according to all scientific evidence the question no longer is if, but how abruptly a global climate change will happen. Several examples are provided of the most recent information on glaciers and ice sheets melting, extremes in the hydrologic cycle, rise in sea temperature and level, and flora and fauna changes as result of the global warming. This chapter also provides references and excerpts from important national and international conventions and legislation regarding the topics addressed. We further discuss the interconnections between global environmental problems and highlight the importance of the following: 1. Current processes are characterized by a nonlinear behavior and we lack the scientific understanding to predict what alterations in one would entail for another process. This means that we do not know the tipping point, which when reached changes can become unpredictable and the magnitude and impact of events may not be of the same order of what was experienced in the past. 2. If the present generation does not come up with adequate protective measures and solutions, and the environment continues to deteriorate on a global scale, many unpredictable events of large scale can eventually be faced by the next generation altering drastically its living conditions. Therefore it is urgent to comprehensively step up conservation efforts of the global environment, with a far-reaching long-term perspective that transcends the generations. 3. Development of solutions to restore the degradation of the environment is complicated by the interconnecting nature of the various ecosystems, i.e., atmosphere, hydrosphere, geosphere, and biosphere that constitute the land. This means that a cooperative and holistic global effort should be considered in developing a viable solution to global environmental problems. 4. Global environmental issues interlock in forming a group of issues which, with the joint cooperation of the international community, need to be comprehensively addressed under a broad and long-term perspective. It is important that all nations take up conservation of the global environment as an important policy task and take initiatives in realizing sustainable development on a global scale. All of the above pose great challenges to modern geoenvironmental engineers as they need to expand significantly their traditional knowledge base and professional role to consider as integral part of their activities an assessment of projects\u27 impact on ecosystems, air, water, and land, and in many cases, consider this beyond a limited, local level. We hope that this chapter aids in this goal of promoting a new definition of geoenvironmental engineering that is urgently needed to address current needs

Chapter 9 Subsurface Contaminant Transport

The mathematical description of groundwater flow, contaminant transport and diffusion through porous media, can be found in many textbooks devoted to the development of governing relationships and solution of the relationships subject to various initial and boundary conditions. The success of the mathematical modeling and the numerical analysis is highly dependent on the quality of the input data and the accuracy in the representation of the physical, chemical, and biological interactions with the transporting fluid and contaminants. In the absence of proper representation, model predication will continue to render unreliable results. Therefore, in this chapter we are concerned with the examination of contaminant transport from the viewpoint of how realistic the models are in representing the physical problem under investigation. The basic physical mechanisms by which miscible (soluble) and immiscible (nonsoluble) contaminants are transported in the subsurface environment were examined. Examples of various analytical models for column experiments, chemical spills, and chemical plumes from continuous releases of contaminants were discussed. In addition, the basic types of apparatus (rigid and flexible wall permeameters) used for the determination of hydraulic properties in laboratory testing were discussed. Experimental techniques (batch equilibrium and soil column leaching) used to determine the adsorption characteristics in the laboratory were examined. The laboratory methods (steady and transient states) used to estimate the transport parameters of chemical species diffusing through waste containment barriers were discussed. The common procedures used to calculate the transport parameters such as decreasing source concentration, time-lag method, and root time method were described and evaluated. The contaminant transport modeling of soluble and nonsalable contaminants using the second postulate of irreversible thermodynamics was presented. Finally, due to variability in parameters and variables in the governing transport equations, it becomes important to treat a variable (e.g., the head or the flux in groundwater flow problems, or the concentration in transport problems) not as a single deterministic solution, but into its mean, variance, and covariance function, or other high-order statistical moments. On that basis, the main issues in stochastic modeling of contaminant transport in soils were highlighted

Chapter 13 Hydraulic Properties of Soils

This chapter addresses the hydraulic properties of soils, which are primarily expressed through the concept of the hydraulic conductivity parameter in Darcy\u27s law. In that respect, it is a companion to Chapter 5 of this book, which provides the background for the material discussed here. Initially, different models to estimate the hydraulic conductivity are presented, followed by laboratory methods of its estimation. The scale effect is particularly emphasized, the discrepancy that has been observed between laboratory and field estimates of hydraulic conductivity, which may range over several orders of magnitude. Field tests, through the pumping of wells in aquifers, are extensively presented. Steady-state solutions are initially discussed, followed subsequently by methods to assess the hydraulic parameters when the test, as is in most cases, has not reached equilibrium flow conditions. Transient radial flow to a well in a confined aquifer is presented through the Theis and the Cooper-Jacob methods. In addition, the Hantush-Jacob method for leaky aquifers, and the Neuman method for pumping tests in unconfined aquifers are described. The chapter also discusses the physical and chemical factors that affect the hydraulic properties of clay mixtures that are used as engineered barriers such as the heterogeneity, soil structure and composition, fracturing, and adsorption capacity, among others. It concludes with the effect that inorganic and organic contaminants may have on the hydraulic properties of soil-based engineered barriers

Chapter 3 Management of Wastes: An International Prospective

Hazardous waste needs to be carefully managed and disposed of as the material classified under this category can ignite, or explode, or react violently with water, air, and other substances, or corrode the drums that the waste is transported or temporarily stored in. Some of this material may also be carcinogenic, or toxic to humans or the environment, infectious, or even present the risk of creating mutations. Because of the danger that hazardous wastes pose, environmental management and regulations, in all phases of their life, are very detailed and stringent in most countries. The United States was the first to enact a comprehensive framework of regulations on hazardous waste with the landmark acts of Resource Conservation and Recovery Act (RCRA) and Comprehensive Environmental Response, Compensation and Liabilities Act (CERCLA). These important pieces of environmental legislations are discussed in detail in order to demonstrate both the complexity of protecting the environment and human populations, and the challenges, but also the trends in waste minimization and disposal. The design criteria and the elements of the disposal facilities for these types of wastes are also discussed here. In addition, the main elements of related pieces of legislation in Canada and in Europe are described and comparisons are provided between the regulatory acts in the United States, Canada, and Europe. This will help the reader realize that environmental legislation in advanced countries shares similar elements, frequently borrowing important insights from another country\u27s regulations, as well as the future trends. Finally, the chapter concludes with a brief exposition of the management and disposal of the most dangerous type of waste that of radioactive waste

Chapter 7 Soil and Contaminant Interaction

This chapter provides details of the complex interactions of the soil constituents and the chemicals that may exist in situ or find their way into a soil. These interactions have important implications for studies and predictions of the movement of contaminants in the subsurface environment as adsorption and other soil-contaminant binding mechanisms may affect the hydraulic conductivity of a geologic medium. Whereas the binding of chemicals on soils solid surfaces may render groundwater remediation techniques ineffective, other chemical and biological processes can provide natural attenuation of contaminated sites. The chapter begins with the commonly used methods to determine the amount of a solute bound by matrix surfaces by Freundich and Langmuir isotherms, together with a discussion of the S-, L-, H-, C-curve isotherms, as well as more advanced descriptions of multicomponent adsorption. Subsequently, the theories by Gouy-Chapman and Stern are presented together with detailed calculations of the electrical charges on the surface of clays, in the Stern layer and the diffuse layer. A brief introduction of first- and second-order kinetics is presented, followed by a detailed exposition of metal cation adsorption, organic contaminant-soil interaction, and of the biological processes that may lead to natural attenuation