Process-Centered Software Engineering Environments, A Brief History and Future Challenges

Software engineering environments have a history of about two decades. Early environments provided support for small fragments of the software process (usually focusing on programming-in-the small). Then there was a trend towards support for more complete software processes (from early phases like requirements analysis and design down to testing and configuration management). Ten years ago the notion of process-centered software engineering environments initiated a new field in software engineering: software process research. The key idea is to use a model of a software process as input parameter for a software engineering environment. The environment is supposed to behave in accordance to the process model. Some aspects of this vision became true, others turned out to be of little practicability. In this article, we discuss the history of software engineering environments with a particular focus on process-centered software engineering environments (PCSEEs). We discuss the notion of distributed software processes (as one of the most substantial current trends in software process research) and we motivate the notion of a software process middleware which serves as basis of real-world software processes spread over various sites. In addition, we discuss some other trends in the software process research arena.     

BPL: A set-based language for distributed system prototyping

Rapid prototyping of software and hardware is recognized as a very important step in timely, cost-effective system development. The complexity inherent in designing distributed computing systems and distributed problem solutions emphasizes the need for effective rapid prototyping tools. ADL/ADS is a testbed user interface tool for experimentation with critical research and design issues pertaining to distributed data processing (DDP). The experimenter expresses a candidate distributed system in terms of experiment objects, along with attributes and relationships. The experiment objects represent hardware, software, and behavior. This paper provides a brief overview of ADL/ADS, and gives especial emphasis to the Behavior Prototyping Language (BPL) within ADL/ADS. BPL is designed for expressing Behavior Modules (B_MODULEs)—the most versatile of the behavior objects. BPL incorporates set-theoretical approaches, and provides syntax designed for effectively describing manipulations of experiment objects, and their attributes and relationships.     

Enhancing the performance of an agent-based manufacturing system through learning and forecasting

Agent-based technology has been identified as an important approach for developing next generation manufacturing systems. One of the key techniques needed for implementing such advanced systems will be learning. This paper first discusses learning issues in agent-based manufacturing systems and reviews related approaches, then describes how to enhance the performance of an agent-based manufacturing system through learning from history (based on distributed case-based learning and reasoning) and learning from the future (through system forecasting simulation). Learning from history is used to enhance coordination capabilities by minimizing communication and processing overheads. Learning from the future is used to adjust promissory schedules through forecasting simulation, by taking into account the shop floor interactions, production and transportation time. Detailed learning and reasoning mechanisms are described and partial experimental results are presented.     

Software agents and issues in personalisation: Technology to accommodate individual users

This paper provides a background to the somewhat nebulous field of computing known as software agent technology. It gives both an overview of some of the key issues faced by the field, and illustrates the context for the papers contained in the rest of the special issue. The paper begins with a brief introduction to the field and proceeds to survey existing work, showing where overlaps exist between agent technology research and interrelated fields such as Human-Computer Interaction (HCI) and Distributed Artificial Intelligence (DAI). The paper then alters focus to concentrate on applications to the personalisation of systems and services to individual users, and techniques which offer opportunities in this area. The other papers in the Special Issue then form the basis for a review of the current state of the art in the personalisation of systems using agent technology. The paper concludes by offering some suggestions for future development of the technologies mentioned.     

Integrated design support system

The integrated design support system (IDS) is a concept for capturing the critical technical engineering information necessary to perform the functions of maintenance, modification, repair, and reprocurement of Air Force weapon systems. The program will first construct an architecture to define the required information. Next, IDS will construct prototype software to acquire, store, distribute, and perform configuration management on the data. The program will conclude with software simulation of the full-scale IDS system operating in a production environment to determine performance characteristics together with development and operatonal costs for the system.     

States and the free orthogonality monoid

Let (X, #) be an orthogonality space such that the lattice C(X, #) of closed subsets of (X, #) is orthomodular and let (, ) denote the free orthogonality monoid over (X, #). Let C₀(, ) be the subset of C(, ), consisting of all closures of bounded orthogonal sets. We show that C₀(, ) is a suborthomodular lattice of C(, ) and we provide a necessary and sufficient condition for C₀(, ) to carry a full set of dispersion free states.The work of the second author on this paper was supported by National Science Foundation Grant GP-9005.     

Fast exponentiation using the truncation operation

Given an integerk, and anarbitrary integer greater than , we prove a tight bound of on the time required to compute with operations {+, –, *, /, ·, }, and constants {0, 1}. In contrast, when the floor operation is not available this computation requires (k) time. Using the upper bound, we give an time algorithm for computing log loga, for alln-bit integersa. This upper bound matches the lower bound for computing this function given by Mansour, Schieber, and Tiwari. To the best of our knowledge these are the first non-constant tight bounds for computations involving the floor operation.     

Logic Based Abstractions of Real-Time Systems

When verifying concurrent systems described by transition systems, state explosion is one of the most serious problems. If quantitative temporal information (expressed by clock ticks) is considered, state explosion is even more serious. We present a notion of abstraction of transition systems, where the abstraction is driven by the formulae of a quantitative temporal logic, called qu-mu-calculus, defined in the paper. The abstraction is based on a notion of bisimulation equivalence, called , n-equivalence, where is a set of actions and n is a natural number. It is proved that two transition systems are , n-equivalent iff they give the same truth value to all qu-mu-calculus formulae such that the actions occurring in the modal operators are contained in , and with time constraints whose values are less than or equal to n. We present a non-standard (abstract) semantics for a timed process algebra able to produce reduced transition systems for checking formulae. The abstract semantics, parametric with respect to a set of actions and a natural number n, produces a reduced transition system , n-equivalent to the standard one. A transformational method is also defined, by means of which it is possible to syntactically transform a program into a smaller one, still preserving , n-equivalence.     

A model for pattern perception with musical applications part II: The information content of pitch structures

This is the second paper of a series which begins by treating the perception of pitch relations in musical contexts and the perception of timbre and speech. The first paper discusses in some detail those properties of musical scales required in order for them to function as reference frames which provide for the measurement of intervals such that ([1], p. 270),Every melodic phrase, every chord, which can be executed at any pitch, can be also executed at any other pitch in such a way that we immediately perceive the characteristic marks of their similarity. Here we continue this discussion by developing quantitative measures of the degree to which different scales possess the above properties. Then that property of musical scales which permits a listener to code the pitches of which it is constituted into degrees is examined and a corresponding quantitative measure developed. Musical scales are shown to be optimal choices with respect to both the former and latter measures, and a theory limiting those scales which are musically useful to a small fraction of possible sets of pitches is proposed. Existing scales which have been examined fall within the theory, which links the techniques of composition which may be used (i.e., those which produce perceptible relations between musical segments) to the above properties of the scale structures. This paper is not self-contained—reading of the previous paper in this series is required.This research was supported in part by grants and contracts AF-AFOSR 881-65, AF 49(638)-1738 and AF-AFOSR 68-1596.     

Stacks,queues, and deques with order-statistic operations

Anorder-statistic deque is a deque that also supports the operationfind(k, D), wherefind(k, D) returns the item inD with rankk. Assumingk is fixed, we show how to implement an order-statistic deque so thatinject(x, D), eject(D), push(x, D), andpop(D) take O(logk) amortized time andfind(k, D) takes worst-case constant time; the time bounds can be made worst case using a technique of Gajewska and Tarjan. We also show our implementations are optimal in the algebraic decision tree model of computation. This deque is applied to three problems: computing order-statistic filters, finding a smallest area convex quadrilateral in the plane, and computing batched order statistics.