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

Hierarchical formal verification using a hybrid tool

We describe a hybrid formal hardware verification tool that links the HOL interactive proof system and the MDG automated hardware verification tool. It supports a hierarchical verification approach that mirrors the hierarchical structure of designs. We obtain the advantages of both verification paradigms. We illustrate its use by considering a component of a communications chip. Verification with the hybrid tool is significantly faster and more tractable than using either tool alone

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

Hybrid verification integrating HOL theorem proving with MDG model checking

In this paper, we describe a hybrid tool for hardware formal verification that links the HOL (higher-order logic) theorem prover and the MDG (multiway decision graphs) model checker. Our tool supports abstract datatypes and uninterpreted function symbols available in MDG, allowing the verification of high-level specifications. The hybrid tool, HOL-MDG, is based on an embedding in HOL of the grammar of the hardware modeling language, MDG-HDL, as well as an embedding of the first-order temporal logic L"m"d"g used to express properties for the MDG model checker. Verification with the hybrid tool is faster and more tractable than using either tools separately. We hence obtain the advantages of both verification paradigms

Proceedings of the 11th International Conference, TPHOLs’98 Canberra, Australia, September–October 1998. Supplementary Proceedings

Mechanical theorem provers for higher order logics have been successfully applied in many areas including hardware verification and synthesis; verification of security and communications protocols; software verification, transformation and refinement; compiler construction; and concurrency. The higher order logics used to reason about these problems and the underlying theorem prover technology that support them are also active areas of research. The International Conference on Theorem Proving in Higher Order Logics (TPHOLs) brings together people working in these and related areas for the discussion and dissemination of new ideas in the field. TPHOLs'98 continues the conference tradition of having both a completed work and work-in-progress stream. The Papers from the first stream were formally refereed, and published as volume 1479 of LNCS. This, supplementary, proceedings records work accepted under the work-in-progress category, and is intended to document emerging trends in higher-order logic research. Papers in the work-in-progress stream are vetted for relevance and contribution before acceptance. The work-in-progress stream is regarded as an important feature of the conference as it provides a venue for the presentation of ongoing research projects, where researchers invite discussion of preliminary results. Although the TPHOLs conferences have their genesis in meetings of the users of the HOL theorem proving system, each successive year has seen a higher rate of contribution from the other groups with similar goals, particularly the user communities of Coq, Isabelle, Lambda, Lego, NuPrl, and PVS. Since 1993 the proceedings have been published by Springer as volumes in Lecture Notes in Computer Science series. Bibliographic details of these publications can be found at the back of this book; more history of TPHOLs can be found with further information about the 1998 event at http://cs.anu.edu.au/TPHOLs98/.Conference Papers: Integrating TPS with Omega By Christoph Benzmuller and Volker Sorge Some Theorem Proving Aids By Paul E. Black and Phillip J. Windley Verification of the MDG Components Library in HOL By Paul Curzon, Sofiene Tahar, and Otmane Ait Mohamed Simulating Term-Rewriting in LPF and in Display Logic By Jeremy E. Dawson A Prototype Generic Tool Supporting the Embedding of Formal Notations By Andrew M. Gravell and Chris H. Pratten Embedding a Formal Notation: Experiences of Automating the Embedding of Z in the Higher Order Logics of PVS and HOL By Andrew M. Gravell and Chris H. Pratten Building HOL90 Everywhere Easily (Well Almost) By Elsa L. Gunter Program Composition in COQ-UNITY : By Francois Marques Formally Analysed Dynamic Synthesis of Hardware By Kong Woei Susanto and Tom Melham Requirements for a Simple Proof Checker By Geoffrey Watson Integrating HOL and RAISE: a practitioner's approach By Wai Wong and Karl R. P. H. Leung Effective Support for Mutually Recursive Types By Peter V. Homeie

Micro-Offsets and Macro-Transformation: An Inconvenient View of Climate Change Justice

We have been asked to examine climate change justice by discussing the methods of allocating the costs of addressing climate change among nations. Our analysis suggests that climate and justice goals cannot be achieved by better allocating the emissions reduction burdens of current carbon mitigation proposals — there may be no allocation of burdens using current approaches that achieves both climate and justice goals. Instead, achieving just the climate goal without exacerbating justice concerns, much less improving global justice, will require focusing on increasing well-being and inducing fundamental changes in development patterns to generate greater levels of well-being with reduced levels of material throughput. We identify several core characteristics of the public and private policy architectures and initiatives necessary to accomplish this task. We also propose examples of short- and long-term initiatives. Our near-term approach recognizes that a focus on public law remedies and nation-states is necessary but not sufficient. We suggest a feasible new mechanism, equity micro-offsets, that could reduce emissions while improving well-being among the poor. Equity micro-offsets can harness altruistic preferences, market mechanisms, and private oversight to reduce emissions and increase well-being in poor countries. Equity micro-offsets also suggest the nature of the long-term political, social, and economic macro-transformation that may be necessary. From household cook stove initiatives to policy architectures that include forestry, agriculture, and other overlooked sectors, achieving climate and justice goals will require transformative approaches, not just improved cost allocations

Establishment of saving and credit scheme in Charambe community

A study was conducted in Charambe Ward at Temeke Municipal through Charambe Development Association (CHADEA). The aim of the study was to conduct needs assessment in order to come up with a proposal to solve some of the existing and pressing community problems. Various problems were mentioned by the CBO leaders, members and some community members; but two problems appeared to be more serious according to the large population of the community. Those problems were unemployment and lack of capital for running and/or expanding the income generating activities. Specific objectives of the study were to conduct needs assessment in order to ascertain the mentioned/ prioritized needs or problems. The study also aimed at establishing whether the large proportion of the population thought that saving and credit scheme can have positive results. Secondly it was to explore the potential of CHADEA to establish and run the scheme in collaboration with the community members. Thirdly it was to establish if the community members had any idea concerning saving and credit schemes. The CHADEA leaders, members and some community members were interviewed. The interview was done using questionnaires to obtain important information about the characteristics (personal data) and other vital information that can assist in the implementation of the project. The findings had it that, the community's population which was estimated to have 700 people, 53.3% was women and 46.7% were men. It was also revealed that, the community is poor in the sense that about 81% of the total population earned an income below 50,000 shillings per month on average. Therefore the problem of lack of capital to majority of the community members became evident. It was also established from the survey results that only 15% of the total population were employed, while 59% were engaged in small business undertakings, 12.5% had nothing to do at all and 12.5% were laborers. The problem of unemployment also became obvious. About education level, the findings revealed that 64.9% had primary education level, 30.3%secondary education (ordinary level) 5.2% went to some collages after secondary school and 4.1% had no education at all. The results indicated that CHADEA is well accepted by the community and the projects are run transparently. About the acceptability of the project the survey results indicated that 56.9% said the scheme would be very useful, 29.8% said the scheme would be useful, 9% said it would be useless and 4.3% said they do not know. Therefore these facts indicated that the large proportion of the community's population thought the project could have a positive impact into their lives. Given these indications of the existence of poverty, and acceptability of the project by a large proportion of the community's population; a project proposal was prepared by the author. The proposal for establishing a saving and credit scheme has been sent to some development partners for grant/loan. The project proposal has been submitted to the African Development Foundation (ADF) to request for Tz shillings 8,720,000 while savings mobilizations is underway to raise some funds internally for the establishment of the project and our target is to collect 600,000 by August 2005. We intent to start up slowly with the little money that would be internally mobilized in case ADF would not give the loan/grant. After we have started we can request for a loan from SELF because one of their condition is that we must start operations and gain experience before borrowing from them. The project outcomes being the improvement of entrepreneur practices, access to financial services among community members. Also to increase the capacity and commitment of CHADEA to encourage savings and borrowing to large number of entrepreneurs and ensure repayment and effectiveness. (Author abstract)Nyella, P. L. (2005). Establishment of saving and credit scheme in Charambe community. Retrieved from http://academicarchive.snhu.eduMaster of Science (M.S.)School of Community Economic Developmen

Fatal Remedies: Child Sexual Abuse and Education Policy in Liberia

An unintended consequence of international education policy is the misunderstanding of the relation between child sexual abuse and the schooling of girls. Development research indicates that education is associated with decreased rates of early childhood marriage. Yet education also exposes female pupils to sexual violence within schools. International agencies and national governments are often unaware that the very policy of putting young girls in the classroom may also expose them to various forms of child sexual abuse. The relation between schooling and sexual violence has not been well established in development research. The field research reported in this dissertation addresses this deficiency in the literature by examining the joint effects of education and the safety of the school environment on female child sexual abuse. Applying a mixed-methods approach, the study analyses results of a 2018 field-study using a stratified-cluster sample of 715 young Liberian women and 493 of their parents. A key finding of the study is the unintended consequence that sending girls to school is linked to nearly 35 percent of students being statutorily raped. While most child rape offenders work outside of the educational setting, approximately 38 percent of abuse cases involve teachers, staff, and adult students. The analysis further examines how the relation between education and child sexual abuse is affected by factors including the knowledge, attitudes, and behaviors of parents. Conclusively, the combination of higher educational achievement (e.g. university, advanced polytechnic schools) and safer learning environments significantly reduces abuse risks. For instance, a girl’s odds of being raped are nearly three times less if she has tertiary education versus primary schooling (phi=0.24, p=0.01). Additionally, a small increase in school safety level reduces her risk of being raped by about 10 percent (p=0.001). Statistical findings were interpreted in light of sixteen key informant interviews, which helped explore causal mechanisms and potential policy solutions. The ethical and policy-relevant ramifications of this research expose a fatal remedy: Policymakers are urging girls to enter the classroom at higher rates, yet without fully understanding how to ensure their protection and facilitate their human agency

Poverty reduction through sustainable development: an assessment of world bank energy strategies in the energy sector in Uganda

Magister Legum - LL