Emerging trends proceedings of the 17th International Conference on Theorem Proving in Higher Order Logics: TPHOLs 2004

technical reportThis volume constitutes the proceedings of the Emerging Trends track of the 17th International Conference on Theorem Proving in Higher Order Logics (TPHOLs 2004) held September 14-17, 2004 in Park City, Utah, USA. The TPHOLs conference covers all aspects of theorem proving in higher order logics as well as related topics in theorem proving and verification. There were 42 papers submitted to TPHOLs 2004 in the full research cate- gory, each of which was refereed by at least 3 reviewers selected by the program committee. Of these submissions, 21 were accepted for presentation at the con- ference and publication in volume 3223 of Springer?s Lecture Notes in Computer Science series. In keeping with longstanding tradition, TPHOLs 2004 also offered a venue for the presentation of work in progress, where researchers invite discussion by means of a brief introductory talk and then discuss their work at a poster session. The work-in-progress papers are held in this volume, which is published as a 2004 technical report of the School of Computing at the University of Utah

Providing a formal linkage between MDG and HOL based on a verified MDG system.

Formal verification techniques can be classified into two categories: deductive theorem proving and symbolic state enumeration. Each method has complementary advantages and disadvantages. In general, theorem provers are high reliability systems. They can be applied to the expressive formalisms that are capable of modelling complex designs such as processors. However, theorem provers use a glass-box approach. To complete a verification, it is necessary to understand the internal structure in detail. The learning curve is very steep and modeling and verifying a system is very time-consuming. In contrast, symbolic state enumeration tools use a black-box approach. When verifying a design, the user does not need to understand its internal structure. Their advantages are their speed and ease of use. But they can only be used to prove relatively simple designs and the system security is much lower than the theorem proving system. Many hybrid tools have been developed to reap the benefits of both theorem proving Systems and symbolic state enumeration Systems. Normally, the verification results from one system are translated to another system. In other words, there is a linkage between the two Systems. However, how can we ensure that this linkage can be trusted? How can we ensure the verification system itself is correct? The contribution of this thesis is that we have produced a methodology which can provide a formal linkage between a symbolic state enumeration system and a theorem proving system based on a verified symbolic state enumeration system. The methodology has been partly realized in two simplified versions of the MDG system (a symbolic state enumeration system) and the HOL system (a theorem proving system) which involves the following three steps. First, we have verified aspects of correctness of two simplified versions of the MDG system. We have made certain that the semantics of a program is preserved in those of its translated form. Secondly, we have provided a formal linkage between the MDG system and the HOL system based on importing theorems. The MDG verification results can be formally imported into HOL to form the HOL theorems. Thirdly, we have combined the translator correctness theorems with the importing theorems. This combination allows the low level MDG verification results to be imported into HOL in terms of the semantics of a high level language (MDG-HDL). We have also summarized a general method which is used to prove the existential theorem for the specification and implementation of the design. The feasibility of this approach has been demonstrated in a case study: the verification of the correctness and usability theorems of a vending machine

The verification of MDG algorithms in the HOL theorem prover

Formal verification of digital systems is achieved, today, using one of two main approaches: states exploration (mainly model checking and equivalence checking) or deductive reasoning (theorem proving). Indeed, the combination of the two approaches, states exploration and deductive reasoning promises to overcome the limitation and to enhance the capabilities of each. Our research is motivated by this goal. In this thesis, we provide the entire necessary infrastructure (data structure + algorithms) to define high level states exploration in the HOL theorem prover named as MDG-HOL platform. While related work has tackled the same problem by representing primitive Binary Decision Diagram (BDD) operations as inference rules added to the core of the theorem prover, we have based our approach on the Multiway Decision Graphs (MDGs). MDG generalizes ROBDD to represent and manipulate a subset of first-order logic formulae. With MDGs, a data value is represented by a single variable of an abstract type and operations on data are represented in terms of uninterpreted function. Considering MDGs instead of BDDs will raise the abstraction level of what can be verified using a state exploration within a theorem prover. The MDGs embedding is based on the logical formulation of an MDG as a Directed Formulae (DF). The DF syntax is defined as HOL built-in data types. We formalize the basic MDG operations using this syntax within HOL following a deep embedding approach. Such approach ensures the consistency of our embedding. Then, we derive the correctness proof for each MDG basic operator. Based on this platform, the MDG reachability analysis is defined in HOL as a conversion that uses the MDG theory within HOL. Then, we demonstrate the effectiveness of our platform by considering four case studies. Our obtained results show that this verification framework offers a considerable gain in terms of automation without sacrificing CPU time and memory usage compared to automatic model checker tools. Finally, we propose a reduction technique to improve MDGs model checking based on the MDG-HOL platform. The idea is to prune the transition relation of the circuits using pre-proved theorems and lemmas from the specification given at system level. We also use the consistency of the specifications to verify if the reduced model is faithful to the original one. We provide two case studies, the first one is the reduction using SAT-MDG of an Island Tunnel Controller and the second one is the MDG-HOL assume-guarantee reduction of the Look-Aside Interface. The obtained results of our approach offers a considerable gain in terms of heuristics and reduction techniques correctness as to commercial model checking; however a small penalty is paid in terms of CPU time and memory usag

Model reductions in MDG-based model checking

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Formally Linking MDG and HOL Based on a Verified MDG System

We describe an approach for formally linking a symbolic state enumeration system and a theorem proving system based on a verified version of the former. It has been realized using a simplified version of the MDG system and the HOL system. Firstly, we have verified aspects of correctness of a simplified version of the MDG system. We have made certain that the semantics of a program is preserved in those of its translated form. Secondly, we have provided a formal linkage between the MDG system and the HOL system based on importing theorems. The MDG verification results can be formally imported into HOL to form a HOL theorem. Thirdly, we have combined the translator correctness theorems and importing theorems. This allows the MDG verification results to be imported in terms of a high level language (MDG-HDL) rather than a low level language. We also summarize a general method to prove existential theorems for the design. The feasibility of this approach is demonstrated in a case study that integrates two applications: hardware verification (in MDG) and usability verification (in HOL). A single HOL theorem is proved that integrates the two results

Generational Portrait of Spanish Society in the Face of Climate Change. A Question to Consider for the Green Economy under the Well-Being Approach

Climate change is emerging as an issue of progressive attention, and therefore awareness, in societies. In this work, the problem is addressed from a generational perspective in Spanish society and is carried out from the approaches of awareness, human action, and self-responsibility. All this from the search of the subjective well-being and the citizens' happiness, as one of the bases of sustainable development initiatives. With data from the European Social Survey R8, from EUROSTAT, we work in two phases: (1) descriptive and inferential on possible associations of the items with the variable Age, and (2) calculation of probabilities between groups through logistic regression. The results confirm a general awareness, but with apparent statistical differences between age groups. In general, the youngest are the most aware, blame human activity most intensely, are the most concerned, and are the most willing to act. And it is the older people who are less aware of all these issues. Based on this finding, and from the approach mentioned above, it is recommended that leaders, both in the macroeconomic and microeconomic sectors, develop initiatives that sensitize and encourage older age groups

Financing Post-2015 Development Goals: Shaping a New Policy Framework for Aid in Liberia

Liberia, Africa\u27s oldest democracy, has made several efforts in becoming a developed economy and ending poverty, but these efforts have been hampered by lack of appropriate financing mechanisms to achieve this goal. The most recent challenge which was the purpose of this study was to understand how Liberia can finance and achieve the sustainable development goals adopted by the United Nations in September 2015. Despite substantial external aid, Liberia was only able to meet 3 out of the 8 Millennium Development Goals, and more than 60% of the population remain extremely poor. The main research question was to understand what policy shifts are need for Liberia to finance its post-2015 development goals. Using Kingdon\u27s multiple streams theory as the lens, a qualitative case study design was used to analyze literature, public reports, government reports, and the loosely-structured interviews of 15 purposefully-selected participants. The interview data were coded and categorized for thematic analysis. Results reveal that Liberia needs to make a policy shift in key areas including domestic resource mobilization, natural resource governance, combating corruption, strengthening the justice system, strengthening capacity for policy processes, and improving political leadership. The positive social change implication of this study includes recommendations for policymakers, the Ministry of Finance, and the donor community to strengthen domestic resource mobilization and undertake pro-poor tax reforms in order to reduce aid dependence, support Liberia\u27s long-term plan to eradicate extreme poverty and become a middle-income country by 2030

Data management and reporting for drinking water quality monitoring in community-managed supplies

Includes bibliographical references (leaves 111-126).Water Service Authorities, which may be district municipalities with hundreds of community-managed supplies under their jurisdiction, are legally responsible for ensuring the quality of water supplied to all consumers. Without the assistance of communities, this requirement, which would involve regular testing in many remote and inaccessible supplies, is extremely difficult to fulfil. Water Service Authorities also struggle to respond timeously to problems in remote supplies, as they are often unaware of the problem for some days. Two-way communication between the Water Service Authority and the Community-based Water Services Provider is therefore essential to an effective monitoring programme. Information and communication technologies, particularly mobile phones on the cellular network, offer potential solution to the challenge of supporting community-managed supplies. Following an investigation into the information needs of various stakeholders in community management, a prototype drinking water quality information system for community-managed supplies was developed