R. McClatchey

The use of production management techniques in the construction of large scale physics detectors

The construction process of detectors for the Large Hadron Collider (LHC) experiments is large scale, heavily constrained by resource availability and evolves with time. As a consequence, changes in detector component design need to be tracked and quickly reflected in the construction process. With similar problems in industry engineers employ so-called Product Data Management (PDM) systems to control access to documented versions of designs and managers employ so-called Workflow Management software (WfMS) to coordinate production work processes. However, PDM and WfMS software are not generally integrated in industry. The scale of LHC experiments, like CMS, demands that industrial production techniques be applied in detector construction. This paper outlines the major functions and applications of the CRISTAL system (Cooperating Repositories and an information System for Tracking Assembly Lifecycles) in use in CMS which successfully integrates PDM and WfMS techniques in managing large scale physics detector construction. This is the first time industrial production techniques have been deployed to this extent in detector construction.

An object model for product and workflow data management

In industry design engineers have traditionally employed Product Data Management Systems to coordinate and control access to documented versions of product designs. However, these systems provide control only at the collaborative design level and are seldom used beyond design. Workflow management systems, on the other hand, are employed in industry to coordinate and support the more complex and repeatable work processes of the production environment. The integration of Product Data Management with Workflow Management can provide support for product development from initial CAD/CAM collaborative design through to the support and optimisation of production workflow activities. This paper investigates this integration and proposes a data model for the support of product data throughout the full development and production lifecycle and demonstrates its usefulness in the construction of large scale high energy physics detectors at the European Particle Physics laboratory at CERN.

Patterns for integrating manufacturing product and process models

In building models for manufacturing, product information has most often been handled separately from process information. The integration of product and process models in a unified data model could provide the means by which information could be shared across a manufacturing enterprise throughout the system lifecycle from design to production. Recently, attempts have been made to integrate these two separate views of systems through identifying common data models. This paper relates description-driven systems to multi-layer architectures and reveals where existing design patterns facilitate the integration of product and process models and where patterns are missing or where existing patterns require enrichment for this integration. It reports on the construction of a so-called description-driven system which integrates product data management (PDM) and workflow management (WfM) data models through a common meta-model.

Scientific workflow management in a distributed production environment

The Compact Muon Solenoid (CMS) high energy physics experiment will comprise several large high resolution detectors each of which will be constructed out of over a million precision parts and will be produced and assembled during the next decade by specialised centres distributed world-wide. Each constituent part of each detector must be accurately measured and tested locally prior to its ultimate assembly and integration in the experimental area at CERN. The CRISTAL (Concurrent Repositories and Information System for Tracking Assembly and production Lifecycles) system is a prototype being developed to monitor and control the production and assembly process of 110000 lead tungstate (PbWO/sub 4/) mono-crystals, and their associated fast electronics, to be installed in the CMS Electromagnetic Calorimeter (ECAL). The software will be generic in design and hence reusable for other CMS detector groups. The paper discusses the distributed computing problems and design issues posed by this project.

Modelling a real time control system based on distributed objects

The CERN Research and Development project (RD-38), named CICERO, aims to identify and design the main building blocks of a generic control information system based on distributed objects. The project is producing an integrating framework (named Cortex) into which user real-time control objects will ultimately be plugged (and played) and a control information system to support its configuration and management. Development of Cortex is following the ESA PSS-05-02 software engineering standards. Cortex is providing an environment which allows real-time control systems to share information, control and analysis functions which presents a uniform human interface; which permits upgrades and additions without code modification; and which is sufficiently generic to allow its use both by existing or future control systems at CERN and by industrial real time control systems. It provides both high level data access, abstracting objects to a level appropriate for on-line control and low level data access to allow views of experimental sub-components for detailed real-time control. Additionally, the Cortex system shall enable developers to grow their control systems from a lab-based test system to the complete experimental system and is therefore both scaleable and flexible to change. Technical solutions are being identified in CICERO which could later be the major components of a basic turnkey control system for future medium to large scale HEP experiments and accelerators as well as for industrial control systems. This paper outlines the modelling concepts behind Cortex.