Digital computers have been used more and more to control different industrial processes during the last decade. As of today, many sy stems are designed to include a process control computer as a vital part. The use of computers has created a need for sophisticated me thods for the operation and supervision of complex industrial proces ses. To summarize the state of the art from the practical as well as from the theoretical point of view, the 4th IFAC/IFIP International Conference on "Digital Computer Applications to Process Control" will be held at Zurich from March 19 to 22, 1974. The first two vo lumes of the proceedings contain the accepted papers submitted to the conference mentioned above. The papers are arranged according to the topics of the conference. A third volume will include the six follow ing survey papers: 1. Digital Control Algorithms Prof. A. P. Sage, Dallas Texas / USA 2. Interface Problems for Process Control Prof. T. J. Williams, Lafayette Indiana / USA 3. Software for Process Computers Dr. J. Gertler, Budapest / Hungary Dr. J. Sedlak, Prague / CSSR 4. Digital Computer Applications in Metallurgical Processes Mr. W. E. Miller, Salem / USA Mr. W. G. Wright, Schenectady / USA 5. Digital Computer Applications in Power Systems Mr. D. Ernst, Erlangen / FRG 6. Digital Computer Applications in Chemical and Oil Industries Dr. H. Amrehn, Marl / FRG We hope, that the publication of these papers from specialists.

Inhalt
Digital Control in Metallurgical Processes.- Control investigations on a nonlinear lumped-parameter model of a sintering process.- Einsatz eines Prozessrechners zur Durchsatzmaximierung an einer quasi-kontinuierlichen fertigungsstrasse.- Dynamic control of multistand aluminum cold rolling mills.- Modèle Numérique pour la simulation de certaines classes de procède métallurgique et son utilisation pour l'optimation de la qualité de produit.- Development of a computer system for the aluminium electrolysis process.- Computer Control of Vuonos Mine.- Multivariable Control of a Five-Stand Cold Mill.- Numerically controlled bending of metal beams.- Improvement in oxygen furnace controllability.- Dynamic control of LD converter with digital computer.- Digital Control in Power Systems.- Use of graphic data screen as operator interface.- Digital control of a hydroelectric power plant.- A dual computer controlled load dispatching system.- Die Ueberwachung eines Teils des schweiz. Hochspannungsnetzes mit State-Estimation, Prozessaufbau und Praktische Erfahrungen.- A simulation study of data acquisition and data communication in a complex power transmission network.- Application of digital control to thermal power plant for automation.- Synthesis of security monitoring schemes in power systems.- Equivalences among model reduction, filter-observer and feedback control design.- Automation of scientific experiments on digital-analog physical complex for investigation of processes in power systems.- Bad data analysis for power system state estimation.- DDC in power plant application and operational results.- A minicomputer based system for suboptimal control and automation of a nuclear research reactor.- Digital controller for a turbine and alternator.- The improvement ofpower system synchronizing and damping torques using adaptive control techniques.- Practical design considerations affecting the use of digital computers in high voltage substations.- On-line security assessment and control of interconnected power systems using sensitivity concept.- Beschreibung des Rechnereinsatzes in Einem Thermo Kraftwerk.- A pattern recognition approach to the preventive evaluation of power system security.- A direct digital control system for a steam power plant.- Frequency control of the Donut system using modern control theory.- Temperature raise control of super critical boiler using derivative digital filter.- Digital load frequency control in a multiarea power system.- Freilastberechnung im Kraftwerk mit Einem Prozessrechner.- Digital Control in Other Processes: Material Handling and Storage, etc..- Use of a process computer to control a high-bay warehouse.- Process control: digital regulation of a turboreactor using A.S.M.O.D.E.E. 01 prototype.- Optimal coupling of an incinerator plant to a district central heating system.- Computer control of a conveyor system.- ASTRA-71, a system for operational control of industrial motor transport in open pits.- Die ÜEberwachung Einer Tiefdruckrotationsmaschine mit Hilfe Eines Prozessrechners.- Computer control of conventional rotary telephone exchanges.- Reliability of Digtal Control.- Reliability of non-redundant digital control computer systems.- Wechselwirkung zwischen prozess, DDC und Back-up bei Hohen Anforderungen an die Betriebssicherheit.- Economics of Digital Control.- Economics of digital control, how, why and where, a case history.- Informationstheoretisch Begrüntiete Qualitätsrriterien für Rechnersysteme und Möglichkeiten zur Einbeziehung Ökonomischer Gesichtspunkte.