Y. Sundblad | KTH Royal Institute of Technology (original) (raw)

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Papers by Y. Sundblad

IFIP Advances in Information and Communication Technology, 2011

General Relativity and Gravitation, 1976

In the past ten years various computer systems have been developed able to perform algebraic calc... more In the past ten years various computer systems have been developed able to perform algebraic calculations. Unfortunately, the fact that there are ready to use, mostly easily attainable, computer languages and programs for manipulation of non-numerical algebraic data is often overlooked by potential users. Several investigations in general relativity have been performed using such systems in the past few years, and in many cases the calculations were of such a length that it would have been prohibitive to complete them without help from a computer. In the first part of the paper we discuss the type of calculations that can be performed by algebraic systems, and several of these relativistic calculations are very briefly reviewed by way of example. In the second and main part of the paper we present a comparative review of most of the leading algebraic systems. To make the comparison more concrete we have taken two calculations from relativity and programed them, as closely as possible, in the same way for all these systems. It is not necessary for a future user who wants to do the same kind of calculations for other metrics to learn the complete syntax of one of these languages. He can make a slight modification to one of our programs, which we are prepared to distribute.

... Just as you were getting to know the mysterious archaeologist, in fact starting to like him; ... more ... Just as you were getting to know the mysterious archaeologist, in fact starting to like him; just when you had become completely immersed by the 3D rendition of the Sahara desert and you find that long lost mummy of an ancient ... dungeon master acts as author, book and memory ...

... Martinus Nijhoff, Dr W. Junk and MTP Press. ... Nils-Erik Gustafsson, Ellcmtel, Stockholm Stu... more ... Martinus Nijhoff, Dr W. Junk and MTP Press. ... Nils-Erik Gustafsson, Ellcmtel, Stockholm Student volunteers: Ann Lam/, KTH Local arrangements: JoAnn Gerdin, KTH ... ECSCW'95 Program Committee Liam Bannon, University of Limerick, Ireland Steve Benford, University of ...

MTOAnvändarperspektivet, 2001

... med UTOPIA,» Utbildning, Teknik ANVÄNDARPERSPEKTIVET I SITT HISTORISKA SAMMANHANG Tjugo års e... more ... med UTOPIA,» Utbildning, Teknik ANVÄNDARPERSPEKTIVET I SITT HISTORISKA SAMMANHANG Tjugo års erfarenhet av kooperativ design med användare Yngve Sundblad ... 1–11 Boivie, P.; Asplund, M.; Ekström, B.; Fransson, K.; Frey, C.; Northman-Alm, T.; Petrelius, ...

Proceedings of the Fourth European Conference on Computer-Supported Cooperative Work ECSCW ’95, 1995

Proceedings of the SIGCHI conference on Human factors in computing systems - CHI '93, 1993

ABSTRACT

Computers & Graphics, 1995

IFIP Advances in Information and Communication Technology, 2011

General Relativity and Gravitation, 1976

In the past ten years various computer systems have been developed able to perform algebraic calc... more In the past ten years various computer systems have been developed able to perform algebraic calculations. Unfortunately, the fact that there are ready to use, mostly easily attainable, computer languages and programs for manipulation of non-numerical algebraic data is often overlooked by potential users. Several investigations in general relativity have been performed using such systems in the past few years, and in many cases the calculations were of such a length that it would have been prohibitive to complete them without help from a computer. In the first part of the paper we discuss the type of calculations that can be performed by algebraic systems, and several of these relativistic calculations are very briefly reviewed by way of example. In the second and main part of the paper we present a comparative review of most of the leading algebraic systems. To make the comparison more concrete we have taken two calculations from relativity and programed them, as closely as possible, in the same way for all these systems. It is not necessary for a future user who wants to do the same kind of calculations for other metrics to learn the complete syntax of one of these languages. He can make a slight modification to one of our programs, which we are prepared to distribute.

... Just as you were getting to know the mysterious archaeologist, in fact starting to like him; ... more ... Just as you were getting to know the mysterious archaeologist, in fact starting to like him; just when you had become completely immersed by the 3D rendition of the Sahara desert and you find that long lost mummy of an ancient ... dungeon master acts as author, book and memory ...

... Martinus Nijhoff, Dr W. Junk and MTP Press. ... Nils-Erik Gustafsson, Ellcmtel, Stockholm Stu... more ... Martinus Nijhoff, Dr W. Junk and MTP Press. ... Nils-Erik Gustafsson, Ellcmtel, Stockholm Student volunteers: Ann Lam/, KTH Local arrangements: JoAnn Gerdin, KTH ... ECSCW'95 Program Committee Liam Bannon, University of Limerick, Ireland Steve Benford, University of ...

MTOAnvändarperspektivet, 2001

... med UTOPIA,» Utbildning, Teknik ANVÄNDARPERSPEKTIVET I SITT HISTORISKA SAMMANHANG Tjugo års e... more ... med UTOPIA,» Utbildning, Teknik ANVÄNDARPERSPEKTIVET I SITT HISTORISKA SAMMANHANG Tjugo års erfarenhet av kooperativ design med användare Yngve Sundblad ... 1–11 Boivie, P.; Asplund, M.; Ekström, B.; Fransson, K.; Frey, C.; Northman-Alm, T.; Petrelius, ...

Proceedings of the Fourth European Conference on Computer-Supported Cooperative Work ECSCW ’95, 1995

Proceedings of the SIGCHI conference on Human factors in computing systems - CHI '93, 1993

ABSTRACT

Computers & Graphics, 1995

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