Lars Walløe#

Professor Walløe's work on demography and population history#

by Professor Sølvi B. Sogner
Department of History
University of Oslo

Professor Walløe's work on demography and population history Professor Walløe's research interests cover an unusually wide range of fields. His expertise in one field frequently enriches research in another and stimulates cross-fertilisation between disciplines. Demography is one of many different subjects that have benefited from his insights.

In 1972-1974, he carried out an interview-based survey on family planning together with a group of medical students. In 1981, he was appointed chair of a government-appointed committee that was asked to draw up a report on the possible consequences of the decline in the birth rate in Norway during the 1970s. The committee's conclusions were published as Official Norwegian Report 1984:26.

Professor Walløe's interest in demography, combined with a keen interest in history, resulted in a study of the population decline in Norway in the late Middle Ages after the Black Death. He published new views on the plague and the way it is transmitted and developed models for simulation of population growth during this period, thus providing valuable input to the scientific debate on the plague.

Professor Walløe has played an active and important role in methodological development in historical demography by making use of his qualifications in medicine, informatics and statistics. He made invaluable contributions to a project on the decline in fertility in Norway in the period 1890-1930 under the auspices of the Norwegian Research Council for Science and the Humanities.

Professor Walløe and informatics#

by Professor Knut Liestøl
Department of Informatics
University of Oslo

For his doctoral thesis, Professor Walløe analysed the transmission of information in neural nets using simulation techniques and information theory. The simulation model was based on a thorough knowledge of the system being modelled. His later work has also reflected this combination of an understanding of biological systems and expertise in modelling. The work for his doctoral thesis resulted in interesting examples of the deduction of system attributes from characteristics of the system's output signal, made possible partly by one of the first research applications of the programming language SIMULA.

Shortly after Professor Walløe completed his doctoral thesis, the first position in cybernetics was established at the University of Oslo. Professor Walløe was appointed, and was able to set the agenda for developments in the field through his own scientific work and the many students he supervised. He also put his administrative skills to good use in building up the new department.

In the first few years after he completed his doctoral thesis, Professor Walløe worked mainly on modelling in the field of neurophysiology, particularly studies of muscle control systems. After this, he began to focus more on blood flow. Two branches of informatics were involved here - signal treatment and simulation. The interest in signal treatment arose because Professor Walløe and his students were at the time actively involved in the development of ultrasound Doppler velocimeters for measuring blood flow, together with the pioneering company VingMed. Simulation was used partly to gain a better understanding of the measurements obtained and also more generally, to understand flow patterns and their importance in normal and pathological physiology.

The research described above was carried out in close cooperation with graduate students and research fellows. Professor Walløe's approach to supervising students has always been an interactive one based to a large extent on discussions. He has also stressed the importance of basing models on a close knowledge of the system that is to be modelled.

Professor Walløe's expertise in modelling has also had a decisive influence on other disciplines than his primary fields of study. For example, when he was involved in the management of major national research programmes on the impacts of acid rain and the regulation of whaling, he ensured that modelling played a key role.

Professor Walløe was head of the Department of Informatics for eight years. The Department was responsible for a young discipline that was developing rapidly and attracting large numbers of students, thus putting great pressure on the Department and its academic staff. Professor Walløe used his impressive administrative capacity to ensure that the Department had sufficient resources for a reasonable rate of growth, including funding for new premises, and to establish simple and non-bureaucratic internal administrative procedures.

Experimental planning and statistical methodology#

by Professor Eva Skovlund
Department of Clinical Cancer Research
Norwegian Radium Hospital

One of Professor Walløe's many fields of interest is statistics. Since the mid-1970s, he has advised medical researchers on the planning and analysis of controlled clinical trials. For several years, he was a member of a committee for clinical trials at the Norwegian Medicines Control Authority.

In addition to applied research, Professor Walløe's interests extend to the theoretical properties of statistical methods. He has focused particularly on the importance of using robust statistical methods, i.e. methods that are not overly sensitive to deviations from the assumptions on which a model is based, for example deviations from normal distribution. He has supervised several graduate students who have studied the robustness of statistical methods using stochastic simulation. This is a much more appropriate method of studying how a statistical method functions in practice than studying its asymptotic properties. A medical experiment usually only involves the collection of a relatively small number of observations, and stochastic simulation, in contrast to asymptotic calculations, makes it possible to study the properties of a method in realistic situations with a small number of observations.

Professor Walløe has also contributed to methodological developments in another field of statistics, sequential methods. The main objective of sequential experiments is to reduce the number of patients it is necessary to include in a clinical trial. Sequential methods differ from traditional methods in that a significance test is run each time the response of a new patient is registered. To determine when enough information has been collected for a trial, specially developed stopping rules are used. Professor Walløe's idea was to use a robust test as a basis and develop stopping rules by stochastic simulation.

In addition to supervising research students working on statistical methods and applied statistics, Professor Walløe has been teaching statistics to medical and pharmaceutical students for many years and has a reputation as a good lecturer. He was co-author of the textbook Elementær statistikk (Elementary statistics), first published in 1977, together with Professor Arnljot Høyland. Unlike most other textbooks at this level, it focuses on non-parametric methods.

Professor Walløe and marine mammal research #

by Professor Arnoldus Schytte Blix
Department of Arctic Biology
University of Tromsø

Professor Walløe became the Norwegian government's main scientific adviser on issues related to marine mammals as a result of three developments during the 1980s.

In 1986-1987, there were huge invasions of harp seals along the coast of Finnmark, Norway's northernmost county. More than 60 000 animals became entangled and died in fishing gear, with serious economic consequences for the population along the coast, but nobody could explain why this occurred.

In 1986, the International Whaling Commission decided to classify the minke whales in Norwegian waters as a "protection stock", with the result that Norwegian minke whaling was discontinued after the 1987 season.

And finally, in 1988 a major international controversy developed about the methods used by Norwegian sealers. Even the King of Sweden was drawn into the debate. As a result, the Norwegian government appointed a commission of inquiry to look into the matter.

These events revealed serious gaps in our knowledge, and in 1988 the Norwegian Council for Fishery Research appointed a planning group chaired by Professor Walløe to establish a Norwegian marine mammal research programme. The programme had an overall budget of more than NOK 100 million, and ran from 1989 to 1994. Professor Walløe was also chairman of its steering committee.

The scientific results of the programme were collected in the book Whales, seals, fish and man and in more popular form in a book in Norwegian entitled Sjøpattedyr - om hval og sel i norske farvann (Marine mammals - whales and seals in Norwegian waters).

The results of the research programme persuaded the Scientific Committee of the International Whaling Commission, where Professor Walløe has been a member and head of the Norwegian delegation since 1989, to accept Norway's estimates of stock size. As a result, Norwegian minke whaling was resumed in 1993. During the period when Professor Walløe has been involved in marine mammal research, we have developed a far better insight into the role of marine mammals in the ecosystem and thus been able to improve fisheries management.

Minke whale