computer science

Ivar Jacobson

Ivar Jacobson is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Ivar Jacobson rather than just read about it. In short: Ivar Hjalmar Jacobson (Swedish pronunciation: [ˈǐːvar ˈjɑ̂ːkɔbˌsɔn] ; born September 2, 1939) is a Swedish computer scientist and software engineer, known as a major contributor to UML, Objectory, Rational Unified Process (RUP), aspect-oriented software development, and Essence. Biography Ivar Jacobson was born in Ystad, on September 2, 1939.

Key takeaways

Ivar Jacobson belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Ivar Jacobson to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Ivar Jacobson from memory before moving on to harder problems.

Reference excerpt

Ivar Hjalmar Jacobson (Swedish pronunciation: [ˈǐːvar ˈjɑ̂ːkɔbˌsɔn] ; born September 2, 1939) is a Swedish computer scientist and software engineer, known as a major contributor to UML, Objectory, Rational Unified Process (RUP), aspect-oriented software development, and Essence.

Biography Ivar Jacobson was born in Ystad, on September 2, 1939. He received his Master of Electrical Engineering degree at Chalmers Institute of Technology in Gothenburg in 1962. After his work at Ericsson, he formalized the language and method he had been working on in his PhD at the Royal Institute of Technology in Stockholm in 1985 on the thesis "Language Constructs for Large Real Time Systems". After his master's degree, Jacobson joined Ericsson and worked in R&D on computerized switching systems AKE and AXE including PLEX. In April 1987, he started Objective Systems. A majority stake of the company was acquired by Ericsson in 1991, and the company was renamed Objectory AB. Jacobson developed the software method Object-Oriented Software Engineering (OOSE) published 1992, which was a simplified version of the commercial software process Objectory (short for Object Factory). In October 1995, Ericsson divested Objectory to Rational Software, and Jacobson started working with Grady Booch and James Rumbaugh. When IBM bought Rational in 2003, Jacobson decided to leave. He formed Ivar Jacobson International (IJI) in mid-2004, which operates with offices in the UK and Sweden. IJI has developed several products providing use cases for Essence, the latest being Essence WorkBench. In 2000, with Agneta Jacobson, he founded Jaczone AB which developed a tool, Waypointer, to support RUP using intelligent agent techniques. Waypointer received a JOLT award in 2004. Ivar Jacobson was awarded the Gustaf Dalén medal from Chalmers University in 2003, and received an honorary doctorate at San Martin de Porres University, Peru, in 2009.

Work

Summary Dr. Ivar Jacobson's contributions span over 50 years, starting from components and architecture in 1967 and still ongoing today with Essence, which is described as "a common ground for engineering". He also created Use Cases, and co-created UML and the Rational Unified Process. His software products include Objectory and the intelligent agent tool Waypointer.

Ericsson In 1967 at Ericsson, Jacobson proposed software components in the new generation of software controlled telephone switches Ericsson was developing. In doing this he also invented sequence diagrams, and developed collaboration diagrams. He also used state transition diagrams to describe the message flows between components. Jacobson saw a need for blueprints for software development. He was one of the original developers of the Specification and Design Language (SDL). In 1976, SDL became a standard in the telecoms industry. In 1986, he also invented use cases as a way to specify functional software requirements.

Rational Software At Rational, Jacobson and his colleagues, Grady Booch and James Rumbaugh, became the original developers of UML, and his Objectory Process evolved to become the Rational Unified Process under the leadership of Philippe Kruchten.

Essential Unified Process In November 2005, Jacobson announced the Essential Unified Process or "EssUP" for short. EssUP was a new "Practice"-centric software development process derived from established software development practices. It integrated practices sourced from three different process camps: the unified process camp, the agile software development camp, and the process improvement (primarily the Capability Maturity Model Integration (CMMI)) camp. Each one of them contributed different capabilities: structure, agility, and process improvement. Ivar has described EssUP as a "super light and agile" RUP. IJI have integrated EssUP into Microsoft Visual Studio Team System and Eclipse.

EssWork Standing on the experience of EssUP Ivar and his team, in particular Ian Spence and Pan Wei Ng, developed EssWork starting in 2006. EssWork is a framework for working with methods. It is based on a kernel of universal elements always prevalent in software development endeavors. On top of the kernel some fifteen practices were defined. A team can create their own method by composing practices.

SEMAT and Essence In November 2009, Jacobson, Bertrand Meyer, and Richard Soley ("the Troika") started an initiative called SEMAT (Software Engineering Method and Theory) to seek to develop a rigorous, theoretically basis for software engineering practice, and to promote its wide adoption by industry and academia. SEMAT has been inspired by the work at IJI, but with a fresh new start. Essence, an OMG standard since November 2014, is the end result of SEMAT. Methods are created as compositions of reusable practices.

Publications Jacobson has published numerous books and articles. A selection:

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Illustrations

Worked examples

Example 1 — a first encounter with Ivar Jacobson

Start with the simplest possible case. Write down what Ivar Jacobson claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Ivar Jacobson before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Ivar Jacobson ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Ivar Jacobson

In research: Ivar Jacobson appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Ivar Jacobson in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Ivar Jacobson is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1939 births, 20th-century Swedish inventors, 21st-century Swedish inventors, so understanding it makes those chapters shorter.
In everyday life: Look for Ivar Jacobson outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Ivar Jacobson in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ivar Jacobson means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Ivar Jacobson out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Ivar Jacobson in simple terms?

Why does Ivar Jacobson matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Ivar Jacobson?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Ivar Jacobson.