Developing frameworks for protocol implementation

This paper presents a method to develop frameworks for protocol implementation. Frameworks are software structures developed for a specific application domain, which can be reused in the implementation of various different concrete systems in this domain. The use of frameworks support a protocol implementation process connected with formal design methods and produce an implementation code easy to extend and to reuse

Applying Formal Methods to Networking: Theory, Techniques and Applications

Despite its great importance, modern network infrastructure is remarkable for the lack of rigor in its engineering. The Internet which began as a research experiment was never designed to handle the users and applications it hosts today. The lack of formalization of the Internet architecture meant limited abstractions and modularity, especially for the control and management planes, thus requiring for every new need a new protocol built from scratch. This led to an unwieldy ossified Internet architecture resistant to any attempts at formal verification, and an Internet culture where expediency and pragmatism are favored over formal correctness. Fortunately, recent work in the space of clean slate Internet design---especially, the software defined networking (SDN) paradigm---offers the Internet community another chance to develop the right kind of architecture and abstractions. This has also led to a great resurgence in interest of applying formal methods to specification, verification, and synthesis of networking protocols and applications. In this paper, we present a self-contained tutorial of the formidable amount of work that has been done in formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial

Testing from a finite state machine: Extending invertibility to sequences

When testing a system modelled as a finite state machine it is desirable to minimize the effort required. It has been demonstrated that it is possible to utilize test sequence overlap in order to reduce the test effort and this overlap has been represented by using invertible transitions. In this paper invertibility will be extended to sequences in order to reduce the test effort further and encapsulate a more general type of test sequence overlap. It will also be shown that certain properties of invertible sequences can be used in the generation of state identification sequences

Cost-effectiveness of Lifestyle Africa: an adaptation of the diabetes prevention programme for delivery by community health workers in urban South Africa

Background Lifestyle Africa is an adapted version of the Diabetes Prevention Program designed for delivery by community health workers to socioeconomically disadvantaged populations in low- and middle-income countries (LMICs). Results from the Lifestyle Africa trial conducted in an under-resourced community in South Africa indicated that the programme had a significant effect on reducing haemoglobin A1c (HbA1c). Objective To estimate the cost of implementation and the cost-effectiveness (in cost per point reduction in HbA1c) of the Lifestyle Africa programme to inform decision-makers of the resources required and the value of this intervention. Methods Interviews were held with project administrators to identify the activities and resources required to implement the intervention. A direct-measure micro-costing approach was used to determine the number of units and unit cost for each resource. The incremental cost per one point improvement in HbA1c was calculated. Results The intervention equated to 71 United States dollars (USD) in implementation costs per participant and a 0.26 improvement in HbA1c per participant. Conclusions Lifestyle Africa reduced HbA1c for relatively little cost and holds promise for addressing chronic disease in LMIC. Decision-makers should consider the comparative clinical effectiveness and cost-effectiveness of this intervention when making resource allocation decisions

Mutation Testing Applied to Validate SDL Specifications

Abstract. Mutation Testing is an error-based criterion that provides mechanisms to evaluate the quality of a test set and/or to generate test sets. This criterion, originally proposed to program testing, has also been applied to specification testing. In this paper, we propose the application of Mutation Testing for testing SDL specifications. We define a mutant operator set for SDL that intends to model errors related to the behavioral aspect of the processes, the communication among processes, the structure of the specification and some intrinsic characteristics of SDL. A testing strategy to apply the mutant operators to test SDL specifications is proposed. We illustrate our approach using the Alternating-Bit protocol

Enhanced financial mechanisms for post 2012 mitigation

Despite the many calls to reform the CDM, its conceptual underpinnings are strong and it will most likely survive in the post-2012 climate regime. Some modifications may be considered in the short term to strengthen the effectiveness and transparency of the mechanism without modifying the Marrakesh Accords. In the medium term substantially increased mitigation efforts in developing countries may require a combination of three possible financial mechanisms: the current activity-based CDM albeit improved, a second market mechanism that would seek to improve the long term emission trends of developing countries by promoting broad based emission reduction programs primarily in the private sector, and a third financial mechanism outside of the market which would be an incentive for the adoption of policy changes leading to a low carbon path, but where emission reductions would not be used as international offsets.Environmental Economics&Policies,Carbon Policy and Trading,Montreal Protocol,Energy and Environment,Environment and Energy Efficiency

A Multi-hop Topology Control Based on Inter-node Range Measurement for Wireless Sensor Networks Node Localization

In centralized range-based localization techniques, sufficiency of inter-node range information received by the base station strongly affects node position estimation results. Successful data aggregation is influenced by link stability of each connection of routes, especially in a multi-hop topology model. In general, measuring the inter-node range is only performed for position determination purposes. This research introduces the use of inter-node range measurement information for link selection in a multi-hop route composition in order to increase the rate of data aggregation. Due to irregularity problems of wireless media, two areas of node communication have been considered. The regular communication area is the area in which other nodes are able to perform symmetrical communication to the node without failure. The irregular area is the area in which other nodes are seldom able to communicate. Due to its instability, some existing methods tried to avoid the irregular area completely. The proposed method, named Virtual Boundaries (VBs) prioritizes these areas. The regular communication area’s nodes have high priority to be selected as link vertices; however, when there is no link candidate inside this area, nodes within the irregular area will be selected with respect to their range to the parent node. This technique resulted in a more robust multi-hop topology that can reduce isolated node numbers and increase the percentage of data collected by the base station accordingly

A Framework for Verifying Data-Centric Protocols

International audienceData centric languages, such as recursive rule based languages, have been proposed to program distributed applications over networks. They simplify greatly the code, while still admitting efficient distributed execution. We show that they also provide a promising approach to the verification of distributed protocols, thanks to their data centric orientation, which allows us to explicitly handle global structures such as the topology of the network. We consider a framework using an original formalization in the Coq proof assistant of a distributed computation model based on message passing with either synchronous or asynchronous behavior. The declarative rules of the Netlog language for specifying distributed protocols and the virtual machines for evaluating these rules are encoded in Coq as well. We consider as a case study tree protocols, and show how this framework enables us to formally verify them in both the asynchronous and synchronous setting