Efficient SMT Solving for Hardware Model Checking

The Satisfiability Modulo Theories (SMT) problem is a decision problem for the satisfiability of first-order formulas with background theories. In the last few years, decision procedures for SMT have been studied intensively, and they are applied successfully to hardware and software verification, compiler optimization, scheduling, and other design automation areas. In particular, during our study, we have found that they are also applicable to constrained random simulation. SMT solvers have been effectively applied to software verification with predicate abstraction and bounded model checking. Only to a lesser extent, they have been applied to hardware verification. In today's hardware designs, bit-level and word-level operations are often tightly intermingled. On some designs, a bit-level model checker may perform better than a word-level model checker or vice versa. In my dissertation, we study several efficient SMT solving techniques that can be applied to hardware model checking and constrained random simulation. In particular, we present a hybrid approach for integer difference logic that combines finite instantiation method with Bellman-Ford algorithm. In addition, we present an efficient term-ITE conversion method that improves SMT solving by word-level simplifications. Efficiency of these techniques have been shown in our SMT solver SatEEn that won the 1st places in Integer Difference Logic (IDL) and Linear Integer Arithmetic Logic (LIA) divisions of SMT Competition 2009. In SMT-based model checking, an efficient encoding plays an important role along with the efficient SMT solving. For hardware model checking, we propose an SMT-based model checking system that consists of modeling and constraint solving components. The modeling component selectively decides the encoding method by analyzing the model, and the constraint solving component uses either Linear Integer Arithmetic Logic (LIA) or Bit-Vector (BV) solver for the encoding. On the other hand, hardware modeling is nontrivial since the behavior of hardware is described with the detailed event semantics of Standard Verilog; hence we define a subset of Verilog with restrictions that guarantee behavioral equivalence between verification condition and simulation of synchronous hardware. The restrictions lead to a concise verification condition and allow controlled nondeterminism that can be easily eliminated for synthesis. In addition, we propose an encoding method that improves SMT solving by maximizing the use of word-level information. For constrained random simulation, we propose to use word-level simplification that reduces the bit-width of each variable in the design

Portable Computer Technology (PCT) Research and Development Program Phase 2

The subject of this project report, focused on: (1) Design and development of two Advanced Portable Workstation 2 (APW 2) units. These units incorporate advanced technology features such as a low power Pentium processor, a high resolution color display, National Television Standards Committee (NTSC) video handling capabilities, a Personal Computer Memory Card International Association (PCMCIA) interface, and Small Computer System Interface (SCSI) and ethernet interfaces. (2) Use these units to integrate and demonstrate advanced wireless network and portable video capabilities. (3) Qualification of the APW 2 systems for use in specific experiments aboard the Mir Space Station. A major objective of the PCT Phase 2 program was to help guide future choices in computing platforms and techniques for meeting National Aeronautics and Space Administration (NASA) mission objectives. The focus being on the development of optimal configurations of computing hardware, software applications, and network technologies for use on NASA missions

Air Traffic Management Abbreviation Compendium

As in all fields of work, an unmanageable number of abbreviations are used today in aviation for terms, definitions, commands, standards and technical descriptions. This applies in general to the areas of aeronautical communication, navigation and surveillance, cockpit and air traffic control working positions, passenger and cargo transport, and all other areas of flight planning, organization and guidance. In addition, many abbreviations are used more than once or have different meanings in different languages. In order to obtain an overview of the most common abbreviations used in air traffic management, organizations like EUROCONTROL, FAA, DWD and DLR have published lists of abbreviations in the past, which have also been enclosed in this document. In addition, abbreviations from some larger international projects related to aviation have been included to provide users with a directory as complete as possible. This means that the second edition of the Air Traffic Management Abbreviation Compendium includes now around 16,500 abbreviations and acronyms from the field of aviation

Space station systems: A bibliography with indexes (supplement 10)

This bibliography lists 1,422 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1, 1989 and December 31, 1989. Its purpose is to provide helpful information to researchers, designers and managers engaged in Space Station technology development and mission design. Coverage includes documents that define major systems and subsystems related to structures and dynamic control, electronics and power supplies, propulsion, and payload integration. In addition, orbital construction methods, servicing and support requirements, procedures and operations, and missions for the current and future Space Station are included

Twitter Analysis to Predict the Satisfaction of Saudi Telecommunication Companies’ Customers

The flexibility in mobile communications allows customers to quickly switch from one service provider to another, making customer churn one of the most critical challenges for the data and voice telecommunication service industry. In 2019, the percentage of post-paid telecommunication customers in Saudi Arabia decreased; this represents a great deal of customer dissatisfaction and subsequent corporate fiscal losses. Many studies correlate customer satisfaction with customer churn. The Telecom companies have depended on historical customer data to measure customer churn. However, historical data does not reveal current customer satisfaction or future likeliness to switch between telecom companies. Current methods of analysing churn rates are inadequate and faced some issues, particularly in the Saudi market. This research was conducted to realize the relationship between customer satisfaction and customer churn and how to use social media mining to measure customer satisfaction and predict customer churn. This research conducted a systematic review to address the churn prediction models problems and their relation to Arabic Sentiment Analysis. The findings show that the current churn models lack integrating structural data frameworks with real-time analytics to target customers in real-time. In addition, the findings show that the specific issues in the existing churn prediction models in Saudi Arabia relate to the Arabic language itself, its complexity, and lack of resources. As a result, I have constructed the first gold standard corpus of Saudi tweets related to telecom companies, comprising 20,000 manually annotated tweets. It has been generated as a dialect sentiment lexicon extracted from a larger Twitter dataset collected by me to capture text characteristics in social media. I developed a new ASA prediction model for telecommunication that fills the detected gaps in the ASA literature and fits the telecommunication field. The proposed model proved its effectiveness for Arabic sentiment analysis and churn prediction. This is the first work using Twitter mining to predict potential customer loss (churn) in Saudi telecom companies, which has not been attempted before. Different fields, such as education, have different features, making applying the proposed model is interesting because it based on text-mining

Technology for large space systems: A bibliography with indexes (supplement 22)

This bibliography lists 1077 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System between July 1, 1989 and December 31, 1989. Its purpose is to provide helpful information to the researcher or manager engaged in the development of technologies related to large space systems. Subject areas include mission and program definition, design techniques, structural and thermal analysis, structural dynamics and control systems, electronics, advanced materials, assembly concepts, and propulsion

Making Felt: Joseph Beuys and the Dalai Lama - un-organizing otherness

"Making Felt: Joseph Beuys and the Dalai Lama - un-organizing otherness" examines the histories and legacies of the 1982 meeting between the German artist Joseph Beuys and his Holiness the Fourteenth Dalai Lama of Tibet, an event that has gone all but unnoticed by historians and theorists. The history of the relationships between both the well-known and marginal figures who were involved with it serves as the connective tissue for the thesis' interrelated objectives. These are: 1) to provide a historical account of the life and work of the meeting's organizer, Dutch artist Louwrien Wijers, and her partnerships with Beuys, French artist Robert Filliou, and Dutch artists Ben d' Annagnac and Gerrit Dekker, which are a crucial part of the meeting and its legacies; 2) to theorize several post-war Western artists' and philosophers' engagements with Eastern thought and religious practices, primarily Zen and Tibetan Buddhism; 3) to historicize the Dalai Lama's first visits to the West (1973 and 1981) which set the stage for his meeting with Beuys; 4) to provide a narrative of 20th-century Western artistic and philosophical practices in terms of encounters with cultural difference, and to use these practices to suggest a notion of 'nonviolence' viable in the 21st-century. The thesis employs the material felt - crucial to Beuys' work - as a device for giving cohesion to its methodology and to the play of histories with which it works. Felt, a non-woven fabric, and the process of making it which involves a methodical leaving-to-chance of the formation of the material- offers a mode of approaching the encounter with otherness that provides an alternative to the usual figuration of cultural knowledge as a regularized ''weave'' of various cultural practices. The thesis uses this distinction between woven and non-woven, making knowledge and making felt, to enable the productive ''un-organization'' of otherness

Remix Perspective: Transdisciplinary Insights for the Art of Writing

How do creative writers transform the complexity of life into literature? Remix Perspectives presents a bricolage synthesis of transdisciplinary insights for workshop leaders and creative writers, appropriated from selected artistic and literary voices from more or less the last hundred years. Seminal concepts from arts such as painting, poetry, dance, music, and photography are gathered here as they inform the arts of literary fiction and creative nonfiction. Thinkers from philosophy, psychology, literary theory, complexity, and metaphysics address the inner and outer realms where the work of the writer is generated and goes forth