Measuring the relative apparent dielectric permittivity of the subsurface is an easy and inexpensive way to indirectly obtain the volumetric water content. Many of the instruments that measure the dielectric, specifically borehole ground penetrating radar, rely on the travel time of an electromagnetic wave through a moist soil. Through inversion of the travel time, the water content can be calculated provided the path over which the wave travels is known exactly. In traditional interpretations of water content, the travel path of the electromagnetic wave is assumed to be direct from the transmitting antenna to the receiving antenna, irregardless of the propagation velocity structure. A new analysis is presented for the interpretation of first arrival travel time measurements from borehole ground penetrating radar during zero-offset profiling that considers critically refracted ray paths. By considering critical refraction at interfaces between contrasting propagation velocities, the travel path becomes dependent upon the velocity structure. Several infiltration experiments were performed to test whether critical refraction occurs in the subsurface. The infiltrating water will change the velocity structure of the subsurface in a predictable manner The interpretations of travel time were then compared to predictions made with an unsaturated flow model and supporting instrumentation. It was found that when critical refraction was not considered, the volumetric water content was underestimated by up to 30%. Correcting for critical refractions, therefore, becomes an important step in properly characterizing the subsurface. The new analysis presented herein may improve our ability to use direct measurements in water resource management practices to assess water availability in semi arid regions.

The main goal of the thesis is to develop a monitoring instrument for climate policy that is based on the Kyoto Protocol and the IPCC guidelines. The instrument developed is based on a "Full Carbon Accounting" approach which takes into account the carbon flows of the biosphere as well as those related to society's metabolism. Conceptually the analysis is based on the epistemological concept of society nature interaction comprising society's metabolism and colonisation of nature as main starting points. This leads to the empirical concept of material flow analysis. The thesis quantifies the carbon flows and the related uncertainties of the Austrian economy for 1990 for selected areas in a consistent way. The thesis also tries to build up a framework for system of indicators that would allow evaluating climate policy. (author´s abstract)

Metamorphism is a technique that mutates the binary code using different obfuscations. It is difficult to write a new metamorphic malware and in general malware writers reuse old malware. To hide detection the malware writers change the obfuscations (syntax) more than the behavior (semantic) of such a new malware. On this assumption and motivation, this thesis presents a new framework named MARD for Metamorphic Malware Analysis and Real-Time Detection. We also introduce a new intermediate language named MAIL (Malware Analysis Intermediate Language). Each MAIL statement is assigned a pattern that can be used to annotate a control flow graph for pattern matching to analyse and detect metamorphic malware. MARD uses MAIL to achieve platform independence, automation and optimizations for metamorphic malware analysis and detection. As part of the new framework, to build a behavioral signature and detect metamorphic malware in real-time, we propose two novel techniques, named ACFG (Annotated Control Flow Graph) and SWOD-CFWeight (Sliding Window of Difference and Control Flow Weight). Unlike other techniques, ACFG provides a faster matching of CFGs, without compromising detection accuracy; it can handle malware with smaller CFGs, and contains more information and hence provides more accuracy than a CFG. SWOD-CFWeight mitigates and addresses key issues in current techniques, related to the change of the frequencies of opcodes, such as the use of different compilers, compiler optimizations, operating systems and obfuscations. The size of SWOD can change, which gives anti-malware tool developers the ability to select appropriate parameter values to further optimize malware detection. CFWeight captures the control flow semantics of a program to an extent that helps detect metamorphic malware in real-time. Experimental evaluation of the two proposed techniques, using an existing dataset, achieved detection rates in the range 94% - 99.6% and false positive rates in the range 0.93% - 12.44%. Compared to ACFG, SWOD-CFWeight significantly improves the detection time, and is suitable to be used where the time for malware detection is more important as in real-time (practical) anti-malware applications. / Graduate / 0984 / alam_shahid@yahoo.com

by Pierre Dersin, Stanley B. Gershwin, Michael Athans. / Includes bibliographical references. / "July, 1976." / Sponsored by the Department of Transportation. DOT/TSC/849

Κύριος στόχος αυτής της εργασίας είναι η παρουσίαση ενός μοντέλου ανάλυσης ροής φορτίου (ΑΡΦ) το οποίο να ανταποκρίνεται στα σύγχρονα συστήματα διανομής με κατανεμημένη παραγωγή. Η ανάλυση ροής φορτίου είναι μία από τις βασικότερες τεχνικές που χρησιμοποιούνται στην μόνιμη ημιτονοειδή κατάσταση ενός συστήματος ηλεκτρικής ενέργειας και ορίζει την βέλτιστη λειτουργία του. Με την ευρεία εισαγωγή στα ΣΗΕ των ανανεώσιμων πηγών, η δομή των παραδοσιακών ΣΗΕ έχει αλλάξει. Σημαντικό μέρος της κατανάλωσης τροφοδοτείται τοπικά και κοντά στα φορτία. Η παραγωγή επομένως αποκτά ολοένα και περισσότερα χαρακτηριστικά κατανεμημένης παραγωγής. Η κατανεμημένη παραγωγή αναπτύσσεται ραγδαία τα τελευταία χρόνια στα συστήματα διανομής. Εξαιτίας αυτής της ανάπτυξης και αλλαγής της δομής του συστήματος επηρεάζεται και η ανάλυση ροής φορτίου. Στην παραδοσιακή ανάλυση ροής φορτίου δεν υπάρχουν πληροφορίες για την κατανομή φορτίου και των απωλειών μεταξύ των κατανεμημένων παραγωγών και της παραγωγής από το σύστημα ηλεκτρικής ενέργειας.. Για τον λόγο αυτό νέα μοντέλα ανάλυσης ροής φορτίου θα πρέπει να σχεδιαστούν. Με την παρούσα εργασία γίνεται μία προσπάθεια επανατοποθέτησης και νέας επίλυσης του προβλήματος της ανάλυσης ροής φορτίου ώστε αυτή να λαμβάνει υπόψη τις κατανεμημένες παραγωγές και την παραγωγή του ΣΗΕ, υπό την έννοια ότι και η κατανεμημένη παραγωγή ορίζεται σε κάθε βήμα και δεν θεωρείται εξαρχής σταθερή. Για το σκοπό αυτό επιλέγει μία νέα κατάστρωση του προβλήματος η οποία η οποία αντικαθιστά τον ζυγό αναφοράς με ένα μοντέλο κατανεμημένου ζυγού αναφοράς στις γεννήτριες παραγωγής του κατανεμημένου συστήματος. Το μοντέλο κατανεμημένου ζυγού αναφοράς εισαγάγει παράγοντες συμμετοχής για την κάθε επιμέρους παραγωγή, οι οποίοι είναι ανάλογοι της επίδρασης που έχει η κάθε μία στις απώλειες του συστήματος. Στην συνέχεια οι παράγοντες συμμετοχής υπολογίζονται με την έννοια των περιοχών γεννήτριας. Η περιοχή μίας γεννήτριας ορίζεται με βάση τη φορά ενεργού ισχύος. Αφού αυτή οριστεί, βρίσκεται η συνεισφορά κάθε παραγωγής στις απώλειες του συστήματος. Είναι προφανές ότι η περιοχή τοποθέτησης των παραγωγών καθώς και οι παράμετροι δικτύου επηρεάζουν την κατανομή των απωλειών σε αυτές. Έτσι δοκιμάζεται μία νέα μέθοδος ΑΡΦ με την τεχνική Newton-Raphson βασισμένη στη νέα δομή του συστήματος. Τα αποτελέσματα δείχνουν να είναι ενθαρρυντικά και βελτιστοποιούν τη συμμετοχή της κατανεμημένης παραγωγής στο σύστημα. / Distribution system operating environments are changing rapidly. With large number of distributed generators (DGs) installed within distribution systems, distribution systems are facing great challenges: the traditional methods for distribution system analysis and planning needs to be revised, and new tools have been developed. This thesis addresses these challenges by using a method of slack bus new modeling. The concept of the distributed slack bus model is used for distribution system analysis and planning. Its impacts on distribution applications are also investigated. The method introduces scalar participation factors to distribute uncertain real power system loss for three-phase power flow calculations. It provides a method to calculate network-based participation factors by using the generator domain based method. Three-phase power flow is a vital analysis tool for distribution systems. In this work, the main objective is to study slack bus modeling and to use the new distributed slack bus model for three-phase power flow. The new method of power flow analysis is tested in a simple power system and the results are satisfactory.

When two computer systems communicate, for example over a network, they must agree on the ordering of bytes within numbers. This ordering is called endianess. Often one of the systems has to swap the order of bytes to the agreed standard. Results of this work help programmers to find places in their program where they forgot to swap the bytes. We have developed a dynamic data-flow analysis built upon the popular Valgrind tool. Compared to the static analysis currently used by the Linux kernel developers, our approach does not require annotation of variables with their endianess. Typically only few places in the program source code will need to be annotated. The analysis can also detect potential bugs that would only manifest if the program was run on computer with opposite endianess. Our approach has been validated on an existing program known to contain yet unfixed endianess problems (RadeonSI OpenGL driver). It has identified all endianess-related bugs and provided useful diagnostic messages together with their location.

In an increasingly globalized world with more and more distributed international supply chains, sustainability studies and policies need to consider socioeconomic and environmental interactions between distant places. Studies of the global biomass metabolism investigate physical flows between and within nature and human systems, thus providing a useful basis for understanding the interrelatedness of changes in one place with impacts elsewhere. Various methodological approaches exist for studying the human-nature metabolism and estimating the land embodied in international trade flows, a core element of assessing telecouplings in the global land system. The results of recent studies vary widely, lacking robustness and thus hampering their application in policy making. This article provides a structured overview and comparative evaluation of existing accounting methods and models for calculating land footprints. We identify differences in available accounting methods and indicate their shortcomings, which are mainly attributable to the product and supply chain coverage and detail, and biases introduced by the use of monetary flows as a proxy for actual physical flows. We suggest options for further development of global land footprint accounting methods, particularly highlighting the advantages of hybrid accounting approaches as a framework for robust and transparent assessments of the global displacement of land use.

Android has been steadily gaining popularity ever since its launch in 2008. One of the major factors for this is the easy availability of a large variety of apps. They range from simple apps such as calculator apps to apps which can help people maintain their schedules and thus man-age many aspects of their lives. In addition, a lot of free apps are available to the user thanks to the power of in-app purchases and advertisements. However, these also raise many security concerns. Apps are privy to a lot of private information regarding the user, such as his contacts, location, etc. It is essential to ascertain that apps do not leak such information to untrustworthy entities. In order to solve this problem, there have been many static and dynamic analyses which aim to track private data accessed or generated by the app to its destination. Such analyses are commonly known as Information Flow analyses. Dynamic analysis techniques, such as TaintDroid, tracks private information and alerts the user when it is accessed by speci c API calls. However, they do not track the path taken by the information, which can be useful in debugging and validation scenarios. The first key contribution of this thesis is a model to perform dynamic information ow analysis, inspired by FlowDroid and TaintDroid, which can retain path information of sensitive data in an efficient manner. The model instruments the app and uses path-edges to track the information flows during a dynamic run. We describe the data structure and transfer functions used, and the reasons for its design based on the challenges posed by the Android programming model and efficiency requirements. The second key contribution is the capability to trace the path taken by the sensitive information based on the information obtained during the analysis, as well as the capability to compliment static analyses such as FlowDroid with the output of this analysis. The tests conducted on the implemented model using DroidBench and GeekBench 3 show the precision and soundness of the analysis, and a performance overhead of 25% while real-world apps show negligible lag. All leaks seen in DroidBench where successfully tracked and were verified to be true positives. We tested the model on 10 real-world apps where we find on average about 16.4% of the total path-edges found by FlowDroid.

Material flow analysis is a main goal of the thesis. To analyse the flows of a material in a well-defined system under study. The goal is to get a transparent understanding of the material flows, to calculate indicators and to develop strategies and measures for improving the material flow systems. Material Flow Analysis thus is the basis for a material flow management.

abstract: The combined heat and power (CHP)-based distributed generation (DG) or dis-tributed energy resources (DERs) are mature options available in the present energy mar-ket, considered to be an effective solution to promote energy efficiency. In the urban en-vironment, the electricity, water and natural gas distribution networks are becoming in-creasingly interconnected with the growing penetration of the CHP-based DG. Subse-quently, this emerging interdependence leads to new topics meriting serious consideration: how much of the CHP-based DG can be accommodated and where to locate these DERs, and given preexisting constraints, how to quantify the mutual impacts on operation performances between these urban energy distribution networks and the CHP-based DG. The early research work was conducted to investigate the feasibility and design methods for one residential microgrid system based on existing electricity, water and gas infrastructures of a residential community, mainly focusing on the economic planning. However, this proposed design method cannot determine the optimal DG sizing and sit-ing for a larger test bed with the given information of energy infrastructures. In this con-text, a more systematic as well as generalized approach should be developed to solve these problems. In the later study, the model architecture that integrates urban electricity, water and gas distribution networks, and the CHP-based DG system was developed. The pro-posed approach addressed the challenge of identifying the optimal sizing and siting of the CHP-based DG on these urban energy networks and the mutual impacts on operation per-formances were also quantified. For this study, the overall objective is to maximize the electrical output and recovered thermal output of the CHP-based DG units. The electrici-ty, gas, and water system models were developed individually and coupled by the devel-oped CHP-based DG system model. The resultant integrated system model is used to constrain the DG's electrical output and recovered thermal output, which are affected by multiple factors and thus analyzed in different case studies. The results indicate that the designed typical gas system is capable of supplying sufficient natural gas for the DG normal operation, while the present water system cannot support the complete recovery of the exhaust heat from the DG units. / Dissertation/Thesis / Ph.D. Electrical Engineering 2013