This paper summarizes the current state of the art and recent trends in software engineering economics. It provides an overview of economic analysis techniques and their applicability to software engineering and management. It surveys the field of software cost estimation, including the major estimation techniques available, the state of the art in algorithmic cost models, and the outstanding research issues in software cost estimation.

Software engineering economics

This report sums up in two volumes the first 50 years of operation of the CERN Proton Synchrotron. After an introduction on the genesis of the machine, and a description of its magnet and powering systems, the first volume focuses on some of the many innovations in accelerator physics and instrumentation that it has pioneered, such as transition crossing, RF gymnastics, extractions, phase space tomography, or transverse emittance measurement by wire scanners. The second volume describes the other machines in the PS complex: the proton linear accelerators, the PS Booster, the LEP pre-injector, the heavy-ion linac and accumulator, and the antiproton rings.

Fifty years of the CERN Proton Synchrotron : Volume 1

Computer assisted controls at the 28 GeV PS made their entry in 1967 and today around 80% of the processes are included in various styles. Beam intensity has since increased two orders of magnitude and interleaved cycles of different beam properties are now serving SPS, ISR and the 28 GeV experimental area. This came about by substantial additions to the accelerator equipment, the main one being the Booster and Linac. Plans up to the end of 1980 include: addition of the Antiproton Accumulation Ring, acceleration of antiprotons in the CPS, the concomitant beam transfer and switching, and multibatch filling of the SPS, requiring cycles times down to 0.65 sec. The improvement programme for controls aims to alleviate the operational and maintenance problems ensuing from this explosive expansion and to create a framework for further growth.

The Improvement Project for the CPS Controls

The CERN PS complex (comprising the 50 MeV Linac, the 800 MeV Booster, the 28 GeV PS and the 3.5 GeV/c Antiproton Accumulator) must deliver beams of various characteristics (e.g. energy, intensity, emittances, ejection mode) to several users, with a repetition time as low as 0.65 s. The SPS accelerator, ISR and LEAR storage rings and the 25 GeV physics experiments receive beams in a repetitive sequence, called a supercycle. The coordination is achieved by the Program Lines Sequencer (PLS) which sends to the equipment concerned (before every machine cycle) a serial message, describing the user and the characteristics of the beam. This message is created by an on-line computer using (i) previously-entered information through a series of application programs and (ii) external conditions coming from the process or the users: these signals in turn can modify the information (i) accordingly.

Pulse-To Pulse Modulation of the Beam Characteristics and Utilization in the CERN PS Accelerator Complex

On the use of neural networks in high-energy physics experiments

The CERN PS accelerator complex has been progressively converted to tull computer controls without interrupting its tull-time operation (more than 6000 hours per year with on average not more than 1% of the total down-time due to controls). The application software amounts to 120 man-years and 450'000 instructions; it compares with other large software projects, also outside the accelerator world: e.g. Skylab's ground support software.1 This paper outlines the application software structure which takes into account technical requirements and constraitnts (resulting from the complexity of the process and its operation) and economical and managerial ones. It presents the engineering and management techniques used to promote implementation, testing and commissioning within budget, manpower and time constraints and concludes with experience gained.

Engineering a Large Application Software Project: The Controls of the CERN PS Accelerator Complex

The new CPS controls system was successfully put into operation on 19 November, 1980, when the 800 MeV Booster, after switching over to the new system, was started up for particle physics. A subset of the new system had already been installed on the Antiproton Accumulator in Spring 1980 and has reliably served several months of engineering run. The Booster machine and control of the CPS cycle generation are now routinely operated by the new system which is based on distributed processing, extensively applying microprocessors in the interface. The problems encountered in converting existing accelerator controls, the control switchover itself and operational experience gained up to the date of the conference are described.

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Start-Up of the New CPS Controls System and Switch-Over of the 800 MeV Booster Controls

A 12-man-year process control software project has been successfully completed in 12 months without interruption of the production process of CERN PS accelerators. After 6 months of careful preparation by a small team, 9 man-years of software, i.e. around 100 control programs amounting to more than 40'000 instructions, have been produced in 6 months by 6 experienced full-time software engineers and 24 part-time engineers and technicians, part of whom had never programmed before. The delivered product met the users specifications, was completed within schedule, conformed to the standards and was fully documented.

Structured design benefits to a process control software project

The CERN PS accelerators have evolved into one of the world's most sophisticated high energy physics facility. The variety of beams and their high repetition rate means that a most sophisticated controls system is required. This reflects on the application software. At the time of the completion of the new control system, nearly 1000 programs, amounting to around 450 000 lines of code, have been developed at the cost of approximately 120 man-years. The span of this software ranges from real-time application programs to special purpose development and management tools. This paper documents the cost, resources and production of this software project. These are analyzed in terms of the structure of the application software. Rules-of-thumb are suggested for estimating the required effort at various phases of the project and to define the implementation strategy.

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A. Daneels

Papers

The Improvement Project for the CPS Controls

Engineering a Large Application Software Project: The Controls of the CERN PS Accelerator Complex

Start-Up of the New CPS Controls System and Switch-Over of the 800 MeV Booster Controls

Structured design benefits to a process control software project

The application software of the CERN PS accelerator controls system — analysis of its cost and resources