2001 克利斯登·奈加特

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Kristen Nygaard

PHOTOGRAPHS
BIRTH:
August 27, 1926, Oslo Norway

DEATH:
August 10, 2002

EDUCATION:
Nygaard got his master's degree in mathematics at the University of Oslo in 1956. His thesis on abstract probability theory was entitled "Theoretical Aspects of Monte Carlo Methods.

EXPERIENCE:
1948 to 1960, Norwegian Defense Research Establishment doing computing and programming (1948–1954) and operational research (1952–1960); 1957 to 1960, head of the operations research group in the Norwegian Defense Establishment; 1959–1964, cofounder and first chairman of the Norwegian Operational Research Society; 1960 on, Norwegian Computing Center (NCC), becoming its Director of Research in 1962; 1975–1976, visiting professor at the University of Aarhus, Denmark, remaining associated with that University until his death in 2002; 1977, professor at University of Oslo; 1987, visiting professor at Stanford University, visiting scientist at Xerox PARC in Palo Alto and a consultant and lecturer at Apple’s Advanced Technology Group.

HONORS AND AWARDS:
Honorary doctorate from Lund University, 1990; first individual to be given an honorary doctorate by Aalborg University, Denmark, 1991; Member of the Norwegian Academy of Sciences; Computer Professionals for Social Responsibility Norbert Wiener Award for Social and Professional Responsibility, 1990; became (together with Ole-Johan Dahl) the first to receive the Rosing Prize (awarded by the Norwegian Data Association for exceptional professional achievements), 1999; awarded an Honorary Fellowship for his originating of object technology concepts by the Object Management Group, of the International Organization for Standardization, 2000; made Commander of the Royal Norwegian Order of St. Olav by the King of Norway, 2000; he and Dahl awarded the Institute of Electrical and Electronic Engineers (for design and implementation of SIMULA 67), 2001; together with Ole-Johan Dahl awarded the ACM A. M. Turing Award, 2001; IEEE John von Neumann Medal, 2002; AITO established an annual prize in the name of Ole-Johan Dahl and Kristen Nygaard to honor their pioneering work on object-orientation, 2004.

The University of Oslo and the University of Aarhus have both named a building after Kristen Nygaard.

KRISTEN NYGAARD DL Author Profile link
Norway – 2001
CITATION
With Ole-Johan Dahl, for ideas fundamental to the emergence of object oriented programming, through their design of the programming languages Simula I and Simula 67.

SHORT ANNOTATED
BIBLIOGRAPHY
RESEARCH
SUBJECTS
Kristen Nygaard is internationally acknowledged as the co-inventor with Ole-Johan Dahl of object-oriented programming and the programming language SIMULA. In addition he was a pioneer of participatory design and the "Scandinavian school of systems development".

Nygaard’s original field was operations research. Early in his career he realized that computer simulations would be a useful tool. He collaborated closely with Ole-Johan Dahl who, in Kristen’s words, “had an exceptional talent for programming”. This collaboration led to the first Simula language, SIMULA I, based on the language ALGOL-60. SIMULA I was originally considered a system description and simulation language, not a general programming language. Dahl & Nygaard quickly realized that its simulation concepts could be applied for programming in general. As a result of this insight they designed Simula 67, later just called SIMULA. It is a general purpose programming language and, like SIMULA I, it contains Algol-60 as a subset.

SIMULA contains the core of the concepts now available in mainstream object-oriented languages such as C++, Eiffel, Java, and C#:

Class and object. The class concept as a template for creating instances (objects).
Subclass. Classes may be organized in a classification hierarchy by means of subclasses.
Virtual methods. A SIMULA class may define virtual methods that can be redefined in subclasses.
Active objects. An object in SIMULA may be the head of an active thread; technically it is a co-routine.
Action combination. SIMULA has an inner-construct for combining the action-parts of a class and its subclass.
Processes and schedulers. SIMULA makes it easy to write new concurrency abstractions, including schedulers.
Frameworks. SIMULA provided the first object-oriented framework in the form of Class Simulation—the mechanism it used to implement its simulation.
Automatic memory management, including garbage collection.
One exception to the broad adoption of SIMULA concepts is the notion of an active object with its own action sequence, which, strangely enough, has not been adapted to other languages. For Dahl & Nygaard, having active objects was an essential facility to be able to simulate concurrent processes from the real world.

Before the concept of object-orientation became popular, SIMULA influenced the development of new abstract data types. As a result of these ideas, Simula was extended with constructs such as public, private and protected modifiers, originally proposed by Jakob Palme.

One unexpected result was that people often found making a model in Simula to be more useful than the actual simulation results. The process of describing the application provided a valuable insight in itself. This led Kristen to formulate one of his favorite aphorisms: To program is to understand. He thought programming should not be considered a low-level technical discipline designed just to accomplish a specific task, but that writing a program should enhance understanding of the problem domain and the solutions.

Nygaard’s next advance was the development, with Petter Håndlykken and Erik Holbæk-Hansen, of DELTA. It was not a programming language, but rather a system description language used to aid in modeling real world systems. It was intended for collaborative use by developers and users together—delta means participate in Norwegian. DELTA was based on SIMULA, but extended with equations for describing both discrete state changes and continuous changes over time.

When Kristen was a visiting professor in Aarhus, Denmark, he initiated work with Bent Bruun Kristensen, Ole Lehrmann Madsen and Birger Møller-Pedersen on the BETA programming language. BETA is a language for describing models of the real world, but, in the tradition of SIMULA, it was also to be useful as an implementation language. In the design of the BETA programming language, a criterion for adding any new construct to the language was that it be meaningful both for modeling and for programming.

In the late sixties, the Norwegian Iron and Metal Workers Union contacted Kristen for help with new computing technologies. Kristen and others developed courses and books about information technologies for the Union. The project developed the first “data agreement” between a union and a company, and elements from this were later included in Norwegian legislation.

The Iron and Metal project was the first of a series of Scandinavian research projects involving users in the design of IT systems. Nygaard was motivated by a desire to empower users to have more influence on these designs. Introducing user participation in systems development was, for many years, considered to be political. Today, however, companies realize that by directly involving users in the design process, the resulting systems are often better. Methods for involving users in the design of IT systems are now known as participatory design, and are taught and practiced by many groups around the world.

Kristen was also one of the few philosophers of informatics, stemming from his early work on simulation. To be able to create a model of real-world phenomena, it is necessary to have a strong conceptual framework to understand and organize knowledge.  Modeling capabilities were always central to his design of languages. One famous example of this is the subclass mechanism, developed to represent domain concept specialization hierarchies.

Kristen was thrilled by the enormous success of the object-oriented approach to programming. During a visit to Xerox PARC, Alan Kay demonstrated the Smalltalk system, and Kirsten was very impressed to see how the ideas from SIMULA had inspired the Smalltalk-team. He was happy to see these ideas further adapted by languages such as Flavours, Loops, C++, Eiffel, Java, C# and many others. He never participated in the critique of possible shortcomings of other languages; on the contrary, he respected their creators and acknowledged their influence on the development of object-orientation.

Hundreds of books were written on object-orientation, but Kristen found that most of these books did not do a good job in teaching the fundamental concepts. He was very concerned with education, but frustrated by what he considered a lack of quality. The goal of his last project (COOL: Comprehensive Object-Oriented Learning) was to develop first-class teaching material on object-oriented programming. He had just set up an international team of participants and was ready to start the work when he died in 2002.

Kristen initiated research on participatory design and object-oriented programming at the University of Aarhus. At the University of Oslo he initiated research on participatory design; Ole-Johan Dahl had already established a research group on object-orientation. His work on system development and on the social impacts of computing technology became the foundation of the Scandinavian School in System Development and the field of participatory design.

But Kristen was not just a pioneer and researcher in informatics. He was an engaged social and political citizen, involved in several aspects of society, including politics. During the intense political fight before the 1972 Referendum on whether Norway should become member of the European Common Market, he worked as coordinator for the large majority of youth organizations that worked against membership. He also was the leader (1990-1995) of Norway's No to the EU movement, which argued against Norwegian membership of the European Union and led to victory in the 1994 referendum.

Further information on Kirsten Nygaard can be obtained from the following:

Memorial site for Kristen Nygaard has further information.
Meyer, Bertrand (ed.), “In memory of Ole-Johan Dahl and Kristen Nygaard,” Journal of Object-Technology, Vol. 1, Num. 4, September-October 2002.
Berntsen, Drude, Knut Elgsaas, and Håvard Hegna, “The Many Dimensions of Kristen Nygaard, Creator of Object-Oriented Programming and the Scandinavian School of System Development,” History of Computing: Learning from the Past, Proceedings of IFIP WG 9.7 International Conference, HC 2010, held as Part of World Computer Congress 2010, Brisbane, Australia, September 20-23, 2010, Tatnall, Arthur (Ed.) ISBN: 978-3-642-15198-9, Springer Berlin Heidelberg New York 2010.
Bent Bruun Kristensen, Ole Lehrmann Madsen, Birger Møller-Pedersen: The When, Why and Why Not of the BETA Programming Language, ACM History of Programming Languages III, San Diego, June 2007.

Author: Ole Lehrman Madsen



克里斯汀-尼加德

照片
出生地：挪威
1926年8月27日，挪威奥斯陆

逝世。
2002年8月10日

教育背景。
尼加德于1956年在奥斯陆大学获得数学硕士学位。他关于抽象概率论的论文题为 "蒙特卡洛方法的理论方面"。

工作经验。
1948年至1960年，在挪威国防研究机构从事计算和编程（1948-1954）以及运筹学研究（1952-1960）；1957年至1960年，担任挪威国防机构运筹学小组组长；1959-1964年，担任挪威运筹学学会的共同创始人和第一任主席；1960年起，担任挪威计算中心（NCC），1962年成为其研究总监。1975-1976年，丹麦奥胡斯大学客座教授，直到2002年去世前一直与该大学保持联系；1977年，奥斯陆大学教授；1987年，斯坦福大学客座教授，帕洛阿尔托的施乐PARC客座科学家和苹果公司先进技术集团的顾问和讲师。

荣誉和奖项。
1990年获隆德大学荣誉博士学位；1991年获丹麦奥尔堡大学荣誉博士学位的第一个人；挪威科学院院士；1990年获计算机专业人士社会责任诺伯特-维纳社会和职业责任奖。1999年，与Ole-Johan Dahl一起成为第一个获得Rosing奖（由挪威数据协会授予的特殊专业成就奖）的人；2000年，被国际标准化组织的对象管理小组授予荣誉奖学金，以表彰他提出的对象技术概念；被挪威国王授予挪威皇家St. 2000年，挪威国王授予他挪威皇家圣奥拉夫勋章；2001年，他和达尔被授予电气和电子工程师协会（因设计和实施SIMULA 67）；2001年，与奥勒-约翰-达尔一起被授予ACM A. M. 图灵奖；2002年，IEEE约翰-冯-诺伊曼奖章；2004年，AITO以奥勒-约翰-达尔和克里斯滕-尼加德的名义设立年度奖，表彰他们在面向对象方面的开创性工作。

奥斯陆大学和奥胡斯大学都以Kristen Nygaard的名字命名了一座建筑。

KRISTEN NYGAARD DL作者简介链接
挪威 - 2001年
参考文献
与Ole-Johan Dahl一起，通过设计编程语言Simula I和Simula 67，为面向对象编程的出现提供了基本的想法。

简短注释
书目
研究
题目
Kristen Nygaard是国际公认的与Ole-Johan Dahl共同发明的面向对象编程和编程语言SIMULA的人。此外，他还是参与式设计和 "斯堪的纳维亚系统开发学校 "的先驱。

尼加德的最初领域是运筹学。在他职业生涯的早期，他意识到计算机模拟将是一个有用的工具。他与Ole-Johan Dahl紧密合作，用Kristen的话说，他 "在编程方面有非凡的天赋"。这次合作导致了第一个Simula语言，SIMULA I，基于ALGOL-60语言。SIMULA I最初被认为是一种系统描述和模拟语言，而不是一种通用的编程语言。Dahl和Nygaard很快意识到，它的模拟概念可以应用于一般的编程。由于这种洞察力，他们设计了Simula 67，后来只称为SIMULA。它是一种通用的编程语言，和SIMULA I一样，它包含Algol-60作为一个子集。

SIMULA包含了现在主流面向对象语言如C++、Eiffel、Java和C#中的核心概念。

类和对象。类的概念作为创建实例（对象）的模板。
子类。类可以通过子类的方式在分类层次中组织。
虚拟方法。一个SIMULA类可以定义虚拟方法，可以在子类中重新定义。
活动对象。SIMULA中的一个对象可以是一个活动线程的头；从技术上讲，它是一个联合程序。
动作组合。SIMULA有一个内部结构，用于组合一个类和它的子类的动作部分。
进程和调度器。SIMULA使编写新的并发性抽象变得容易，包括调度器。
框架。SIMULA以类模拟的形式提供了第一个面向对象的框架--它用来实现模拟的机制。
自动内存管理，包括垃圾收集。
广泛采用SIMULA概念的一个例外是具有自己的动作序列的活动对象的概念，奇怪的是，这个概念没有被改编到其他语言。对于Dahl和Nygaard来说，拥有活动对象是能够模拟现实世界中的并发过程的一个基本设施。

在面向对象的概念变得流行之前，SIMULA影响了新的抽象数据类型的发展。由于这些想法，Simula被扩展了一些结构，比如最初由Jakob Palme提出的public、private和protected修改器。

一个意想不到的结果是，人们常常发现用Simula制作模型比实际的模拟结果更有用。描述应用的过程本身就提供了一个有价值的见解。这导致克里斯汀提出了他最喜欢的一句箴言。编程是为了理解。他认为编程不应该被认为是一门低层次的技术学科，只是为了完成一项具体的任务，而编写程序应该加强对问题领域和解决方案的理解。

Nygaard的下一个进展是与Petter Håndlykken和Erik Holbæk-Hansen一起开发的DELTA。它不是一种编程语言，而是一种系统描述语言，用于帮助对现实世界的系统进行建模。它的目的是让开发人员和用户一起协作使用--DELTA的意思是参与挪威语。DELTA以SIMULA为基础，但扩展了描述离散状态变化和连续时间变化的方程式。

当Kristen在丹麦奥胡斯担任客座教授时，他与Bent Bruun Kristensen、Ole Lehrmann Madsen和Birger Møller-Pedersen开始了BETA编程语言的工作。BETA是一种描述现实世界模型的语言，但是，按照SIMULA的传统，它也可以作为一种实施语言使用。在BETA编程语言的设计中，向该语言添加任何新结构的标准是，它对建模和编程都有意义。

在60年代末，挪威钢铁和金属工人工会与克里斯汀联系，寻求对新计算技术的帮助。克里斯汀和其他人为该联盟开发了关于信息技术的课程和书籍。该项目开发了工会和公司之间的第一个 "数据协议"，其中的内容后来被纳入挪威立法。

钢铁项目是斯堪的纳维亚地区一系列研究项目中的第一个，该项目让用户参与了IT系统的设计。Nygaard的动机是希望授权用户对这些设计有更多的影响。多年来，在系统开发中引入用户参与被认为是一种政治行为。然而，今天，公司意识到，通过直接让用户参与设计过程，所产生的系统往往会更好。让用户参与IT系统设计的方法现在被称为参与式设计，并被全世界的许多团体所教授和实践。

Kristen也是为数不多的信息学哲学家之一，这源于他早期的模拟工作。为了能够创建一个真实世界现象的模型，必须有一个强大的概念框架来理解和组织知识。 建模能力始终是他设计语言的核心。其中一个著名的例子是子类机制，它的开发是为了表示领域概念的专业化层次。

Kristen对面向对象的编程方法的巨大成功感到兴奋。在访问Xerox PARC期间，Alan Kay展示了Smalltalk系统，Kirsten看到来自SIMULA的想法是如何启发Smalltalk-团队的，对此他印象深刻。他很高兴看到这些想法被Flavours、Loops、C++、Eiffel、Java、C#等语言进一步调整。他从未参与过对其他语言可能存在的缺点的批评；相反，他尊重他们的创造者，并承认他们对面向对象的发展的影响。

有几百本关于面向对象的书，但Kristen发现大多数这些书在教授基本概念方面做得并不好。他非常关心教育问题，但对他认为缺乏质量的问题感到沮丧。他最后一个项目（COOL：综合面向对象学习）的目标是开发一流的面向对象编程的教学材料。他刚刚成立了一个由参与者组成的国际团队，并准备在2002年去世时开始这项工作。

Kristen在奥胡斯大学发起了关于参与式设计和面向对象编程的研究。在奥斯陆大学，他发起了对参与式设计的研究；Ole-Johan Dahl已经建立了一个关于面向对象的研究小组。他在系统开发和计算技术的社会影响方面的工作成为斯堪的纳维亚系统开发学校和参与式设计领域的基础。

但克里斯汀不仅仅是一个信息学的先驱和研究者。他是一个参与的社会和政治公民，参与了社会的多个方面，包括政治。在1972年关于挪威是否应该成为欧洲共同市场成员的公民投票前的激烈政治斗争中，他担任了大多数反对加入的青年组织的协调人。他还是挪威 "反对欧盟 "运动的领导人（1990-1995年），该运动反对挪威加入欧盟，并在1994年的全民公决中取得胜利。

关于克尔斯滕-尼加德的进一步信息可从以下方面获得。

克里斯滕-尼加德的纪念网站有进一步的信息。
Meyer, Bertrand (ed.), "In memory of Ole-Johan Dahl and Kristen Nygaard," Journal of Object-Technology, Vol. 1, Num. 4, September-October 2002.
Berntsen, Drude, Knut Elgsaas, and Håvard Hegna, "Kristen Nygaard的许多方面，面向对象编程和斯堪的纳维亚系统开发学校的创造者，" 计算机历史。从过去学习，IFIP工作组9.7国际会议论文集，HC 2010，作为2010年世界计算机大会的一部分举行，澳大利亚布里斯班，2010年9月20-23日，Tatnall, Arthur (Ed.) ISBN: 978-3-642-15198-9, Springer Berlin Heidelberg New York 2010.
Bent Bruun Kristensen, Ole Lehrmann Madsen, Birger Møller-Pedersen: The When, Why and Why Not of the BETA Programming Language, ACM History of Programming Languages III, San Diego, June 2007.

作者。Ole Lehrman Madsen