Deriving real-time action systems with multiple time bands using algebraic reasoning

The verify-while-develop paradigm allows one to incrementally develop programs from their specifications using a series of calculations against the remaining proof obligations. This paper presents a derivation method for real-time systems with realistic constraints on their behaviour. We develop a high-level interval-based logic that provides flexibility in an implementation, yet allows algebraic reasoning over multiple granularities and sampling multiple sensors with delay. The semantics of an action system is given in terms of interval predicates and algebraic operators to unify the logics for an action system and its properties, which in turn simplifies the calculations and derivations

Quiescent consistency: Defining and verifying relaxed linearizability

Concurrent data structures like stacks, sets or queues need to be highly optimized to provide large degrees of parallelism with reduced contention. Linearizability, a key consistency condition for concurrent objects, sometimes limits the potential for optimization. Hence algorithm designers have started to build concurrent data structures that are not linearizable but only satisfy relaxed consistency requirements. In this paper, we study quiescent consistency as proposed by Shavit and Herlihy, which is one such relaxed condition. More precisely, we give the first formal definition of quiescent consistency, investigate its relationship with linearizability, and provide a proof technique for it based on (coupled) simulations. We demonstrate our proof technique by verifying quiescent consistency of a (non-linearizable) FIFO queue built using a diffraction tree. © 2014 Springer International Publishing Switzerland

Viewpoint consistency in Z and LOTOS: A case study

Specification by viewpoints is advocated as a suitable method of specifying complex systems. Each viewpoint describes the envisaged system from a particular perspective, using concepts and specification languages best suited for that perspective. Inherent in any viewpoint approach is the need to check or manage the consistency of viewpoints and to show that the different viewpoints do not impose contradictory requirements. In previous work we have described a range of techniques for consistency checking, refinement, and translation between viewpoint specifications, in particular for the languages LOTOS and Z. These two languages are advocated in a particular viewpoint model, viz. that of the Open Distributed Processing (ODP) reference model. In this paper we present a case study which demonstrates how all these techniques can be combined in order to show consistency between a viewpoint specified in LOTOS and one specified in Z. Keywords: Viewpoints; Consistency; Z; LOTOS; ODP

Defining correctness conditions for concurrent objects in multicore architectures

Correctness of concurrent objects is defined in terms of conditions that determine allowable relationships between histories of a concurrent object and those of the corresponding sequential object. Numerous correctness conditions have been proposed over the years, and more have been proposed recently as the algorithms implementing concurrent objects have been adapted to cope with multicore processors with relaxed memory architectures. We present a formal framework for defining correctness conditions for multicore architectures, covering both standard conditions for totally ordered memory and newer conditions for relaxed memory, which allows them to be expressed in uniform manner, simplifying comparison. Our framework distinguishes between order and commitment properties, which in turn enables a hierarchy of correctness conditions to be established. We consider the Total Store Order (TSO) memory model in detail, formalise known conditions for TSO using our framework, and develop sequentially consistent variations of these. We present a work-stealing deque for TSO memory that is not linearizable, but is correct with respect to these new conditions. Using our framework, we identify a new non-blocking compositional condition, fence consistency, which lies between known conditions for TSO, and aims to capture the intention of a programmer-specified fence

Toward a Sustainable Leadership Model for Pastoral Leaders

Leadership is a dynamic process. Pastoral leadership, though often times rewarding, can also be challenging. Insofar as pastoral leaders are equipped and have the leadership agility and dexterity to effectively manage through the demands of their call, their emotional intelligence abilities and transformational leadership behaviors may prove invaluable when being leveraged toward mission effectiveness, funding, and volunteer involvement. Emotional intelligence and transformational leadership are viable constructs that serve as the conceptual frameworks for this research. Enabling pastoral leaders to enhance their leadership skill through the development of these respective constructs offers benefits to the pastoral leaders and the member constituents and communities they serve. The purpose of this study was to examine and better understand the relationship between the emotional intelligence abilities and transformational leadership behaviors of pastoral leaders and the subsequent linear correlation to pastoral leader’s effectiveness. Results indicated that no significant relationship was found between the identified characteristics of emotional intelligence abilities, transformational leadership behavior, and pastoral leader effectiveness. The primary aim of this research was to aid, inform, and improve those who serve as pastoral leaders toward the maximization of the respective mission of their respective organization. The population for this study (N = 267) was pastoral leaders from within the respective faith traditions of the various New Thought Christian movements and the Church of the Nazarene

Constructing identity in place : Celia Thaxter and the Isles of Shoals

This study explores rhetorical constructions of place and self in the non-fiction narratives and letters of Celia Laighton Thaxter. Thaxter was a 19th century poet, journalist and writer who grew up on the Isles of Shoals off the coast of New Hampshire. Widely published in her day, Thaxter was one of the foremothers of American nature writing. This study considers the significance of place in relation to Thaxter’s development as an individual and as a writer. The study finds that the Isles o f Shoals provided a foundation for Thaxter’s personal and professional identities. Thaxter’s relationship with the Shoals was intimate and personal, taking on many of the dimensions of a human relationship. This study also emphasizes the juxtaposition of Thaxter’s island and inland lifestyles and their influence on Thaxter. Writing is found to be a vehicle through which Thaxter successfully integrated her “island self’ and “inland self.

The Small Claims Courts Act: Annotations and comments

From text: Small Claims Courts are a familiar feature of our legal environment. Foreign in conception, they have extended their roots widely and deeply in South African soil. Their presence here is easily affirmed

Total Factor Productivity of Philippine Manufacturing Industries

As suggested by vast literature, the Philippine economy has performed poorly over the last three decades due to deterioration in productivity. This paper provides an updated productivity estimates for the manufacturing industries over the period 1956-1992. This paper decomposes this industry productivity growth into technical progress and technical efficiency. It also analyzes the patterns of industry productivity through results of regression method.total factor productivity, manufacturing sector, technical efficiency, output growth

Weak refinement in Z

An important aspect in the specification of distributed systems is the role of the internal (or unobservable) operation. Such operations are not part of the user interface (i.e. the user cannot invoke them), however, they are essential to our understanding and correct modelling of the system. Various conventions have been employed to model internal operations when specifying distributed systems in Z. If internal operations are distinguished in the specification notation, then refinement needs to deal with internal operations in appropriate ways. However, in the presence of internal operations, standard Z refinement leads to undesirable implementations. In this paper we present a generalization of Z refinement, called weak refinement, which treats internal operations differently from observable operations when refining a system. We illustrate some of the properties of weak refinement through a specification of a telecommunications protocol

Total Factor Productivity of Philippine Manufacturing Industries

As suggested by vast literature, the Philippine economy has performed poorly over the last three decades due to deterioration in productivity. This paper provides an updated productivity estimates for the manufacturing industries over the period 1956-1992. This paper decomposes this industry productivity growth into technical progress and technical efficiency. It also analyzes the patterns of industry productivity through results of regression method.total factor productivity, manufacturing sector, technical efficiency, output growth