A formal model for the interoperability of service clouds

Large-scale service-oriented computing is based on the idea that services from various servers are combined into one distributed application. Referring to a collection of services on one server as a ??service cloud??, the problem investigated in this paper is to define formal high-level specifications of such distributed applications and to enable the location of suitable services for them. Based on the language-independent model of Abstract State Services (AS²s), which serves as a universal integrated model for data and software as services, we extend AS²s by high-level action schemes called ??plots?? as a means to specify permitted sequences of service operations. On these grounds, we develop a model for service mediators, that is, specifications of composed services in which service slots have to be filled by actual services, and investigate matching conditions for slots of mediators and services. For a services to match a slot in a mediator, a (generalised) projection of the mediator must comply with the plot of the service. Furthermore, the service must be semantically adequate, which requires the use of a service ontology.     

The landing gear case study: challenges and experiments

International Journal on Software Tools for Technology Transfer -     

Typed Abstract State Machines for data-intensive applications

This paper focuses on extensions of Abstract State Machines (ASMs) for the benefit of a refinement calculus in the area of data-intensive applications, in particular data warehouses and on-line analytical processing. The extensions lead to a typed version of ASMs and a more specific notion of strong data refinement, which incorporates the preservation of information content by means of schema dominance. Each typed ASM can be effectively translated into an equivalent ordinary one. Providing typed ASMs helps to exploit the existing logical formalisms used in data-intensive applications to define a ground model. Furthermore, strong data refinement helps to set up a refinement-based development method that uses provably correct standard refinement rules.     

Axiomatisations of functional dependencies in the presence of records,lists, sets and multisets

We investigate functional dependencies in databases that support complex values such as records, lists, sets and multisets. Therefore, an abstract algebraic framework is proposed that classifies data models according to the underlying types they support. This allows to emphasise the impact of the data types rather than the specifics of a particular data model.     

A room-based diagnostic imaging system for measurement of patient setup

A room-based diagnostic x-ray imaging system for routine measurement of radiotherapy patient orientation has been developed. The system consists of a pair of room-mounted x-ray tubes and a portable imager consisting of an orthogonal pair of phosphor screens, a mirror/lens system, a CCD camera, and computer software for comparing images of the patient to reference images. Orthogonal pairs of images can be acquired quickly and with relatively little exposure, allowing correction of patient setup on a daily basis. This could limit patient setup error to the uncertainty in the measurement and repositioning processes, a potentially significant improvement over the present standard.     

Marketing the MIS

The promise of management information systems has not yet been realized; low utilization rates by line decision-makers may be one cause. This paper suggests that the effort of marketing the MIS is as important as the work of both the MIS design and implementation phases combined. Various MIS “markets” are segmented, and marketing mix strategies which could encourage greater MIS usage are developed. An application of these marketing strategies for an advanced MIS is provided as an illustration.     

Herd-level variables associated with delayed milk ejection in Michigan dairy herds

The objective of this study was to determine which herd-level variables were associated with delayed milk ejection (bimodal milk let-down) in 64 Michigan dairy herds. Median herd size was 294 cows (range 59 to 2,771 cows). For each herd, milking protocols were observed and milk flow dynamics were estimated by use of digital vacuum recorders. Surveys were also administered to the producers to measure mastitis management practices and attitudes. Milk flow dynamics were recorded for a total of 3,824 cow milkings, with a mean of 60 milkings per herd (range of 11 to 154). Backward multivariable analysis was used to determine which of the 47 herd-level milking and management variables were associated with delayed milk ejection (cows with milk let-down periods between milking cluster attachment and the incline phase of milk flow of >30 s). Delayed milk ejection occurred in an average of 25% of the cows in each herd (range 0 to 75%). A multivariable model found that the proportion of cows in a herd with delayed milk ejection was negatively associated with mean total time of tactile stimulation during premilking routines and positively associated with herd size.     

Herd-level variables associated with premilking stimulation time in Michigan dairy herds

The objective of this study was to determine the herd-level variables that were associated with total stimulation time during the premilking routine in 64 Michigan dairy herds. The mean herd size was 452 cows (range = 59 to 2,771 cows). For each herd, surveys were administered to producers to gather mastitis management practices and attitudes. Additionally, milking protocols were observed and milk flow dynamics were measured by use of digital vacuum recorders. Backward multivariate regression analysis was used to determine which of 47 herd-level milking and management variables were associated with mean total stimulation time. Mean total stimulation time was 14.2 s (range = 2.4–40.8 s) and was positively associated with increasing latency period (time interval between first stimulation and cluster attachment). Total stimulation time was negatively associated with greater herd size and number of visits to each cow in the premilking routine. In summary, increased stimulation time is more likely in herds that foster a lower sense of urgency of cow throughput during milking, as evidenced by a positive association with longer latency periods and fewer preparation visits per cow. Tactile stimulation is critical for efficient milk ejection; if inadequate, cows are at greater risk of delayed milk ejection and bimodal milk flow, which in turn has been associated with teat congestion and reduced milk flow. This study offers insight as to some of the herd factors that may be limiting adequate tactile stimulation.     

Bounded synthesis

A fundamental challenge in the synthesis of reactive systems is the size of the search space: the number of candidate implementations of a temporal specification is typically superexponential or even, for distributed system architectures, infinite. In this article, we introduce the bounded synthesis approach, which makes it possible to traverse this immense search space in a structured manner. We fix a bound on a system parameter, such as the number of states, and limit the search to those implementations that fall below the bound. By incrementally expanding the search to larger bounds, we maintain completeness, while orienting the search towards the simplest (and often most useful) solutions. The technical backbone of this solution is a novel translation from formulas of linear-time temporal logic to sequences of safety tree automata, which are guaranteed to underapproximate the specification and to eventually become emptiness-equivalent. Bounded synthesis is applicable to the entire range of synthesis problems, from individual processes to synchronous and asynchronous distributed systems, to systems with additional design constraints, such as symmetry. We include experimental results from a SMT-based implementation, which demonstrate that bounded synthesis solves many synthesis problems that were previously considered intractable.