Wireless Sensor Networks (WSNs) are widely adopted for applications ranging from surveillance to environmental monitoring. While powerful and relatively inexpensive, they are subject to behavioural faults which make them unreliable. Due to the complex interactions between network nodes, it is difficult to uncover faults in a WSN by resorting to formal techniques for verification and analysis, o...

The main aim of this paper is to construct menarcheal life-table of Nepal using sample survey data. An alternative technique for the construction such as a life-table based on models has been proposed. The construction of such a life-table describes the distribution of the waiting time for getting menarche at birth as well as some specified age or age group of girls (in years). The average expe...

Internet services can now be used from mobile terminals. The main standard supporting this technology, WAP, will enable new services since it is compatible with network technologies like IP and UMTS. In parallel, powerful methods must be proposed to validate the underlying protocols in order to guaratee reliability and interoperability of new products. Our work, based on formal methods, contrib...

The spatial discretization of nonlinear partial differential equations (PDEs) results in large systems of nonlinear ordinary differential equations (ODEs). The discretization of the Brusselator equation is a characteristic example. For the parallel numerical solution of the Brusselator equation we use an iterated Runge-Kutta method. We propose modifications of the original method that exploit t...

Tool support is known to be one of the success factors in formal specification based analysis and -program development. This paper investigates tool support in the context of a case study where a wide range of tool features is required: For an access control, C++ code has to be developed based on the user’s requirements expressed in natural language. The access control has been classified a mix...

We present DHARMA, a distributed high assurance reference monitor that is generated mechanically by the formal methods tool PVS from a verified specification of its key algorithms. DHARMA supports policies that allow delegation of access rights, as well as structured, distributed names. To test DHARMA, we use it as the core reference monitor behind a web server that serves files over SSL connec...

The Trace Assertion Method (in short: TAM) is a formal method for abstract specification of interfaces of software modules being designed according to the “information hiding” principle. A trace specification is a “black-box” specification, i.e., it describes only those features of a module that are externally observable. The method was introduced by W. Bartusek and D.L. Parnas some 15 years ag...

We propose a formal model for reputation-based trust management. In contrast to credential-based trust management, in our framework an agent’s reputation serves as the basis for trust. For example, an access control policy may consider the agent’s reputation when deciding whether to offer him a license for accessing a protected resource. The underlying semantic model is an event semantics inspi...

In Ethiopia, modern contraceptive prevalence among currently married women nearly tripled over the last decade, but the method mix remains skewed toward short-acting methods. Since 2011, the Integrated Family Health Program (IFHP+), jointly implemented by Pathfinder International and John Snow Inc., has supported the Federal Ministry of Health to introduce intrauterine devices (IUDs) in more th...

Among many existing algorithms, convergence methods are the most popular means of computing square root and the reciprocal of square root of numbers. An initial approximation is required in these methods. Look up tables (LUT) are employed to produce the initial approximation. In this paper a number of methods are suggested to reduce the size of the look up tables. The precision of the initial a...