K. Nygaard K. and O-J. Dahl. Simula an Algol-based Simulation Language. CACM, 9:671--678, September ####.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... For example, the language CLU and the safe subset of the Cedar language are both in this family and completely type safe [1,18] SIMULA 67, an extension of ALGOL 60 frequently hailed as the first object oriented language, is also among the first languages incorporating a notion of subtyping [2,8]. Recall that this is the idea that some types are subsets of others. A SlMULA pro grammet can set up complex hierarchies of types, or classes , each of which inherits attrib.utes of types above it in the hierarchy. Procedures that ask for an argument of a particular type will accept one of a ....

Dahl, Ole-Johan and Nygaard, Kristen, SIMULA--an ALGOL-Based Simulation Language, Comunications o the ACM, v.9, n.9 (September 1966), pp. 671-678.

....6 compares inheritance. Section 7 presents the conclusion that, while both approaches m e viable, the programming by extension approach is prefen ed. 2. Outline of the two approaches 2. 1 The class based approach The class based approach is influenced by programming languages such as Simula [5], Smalltalk [7] C [15] and Java [8] where a specific language construct to encapsulate state and operations is defined (a class) Derived classes inherit state and operations from superclasses, with possible augmentation or modification. An object is an instance of a class, and contains ....

O.J. Dahl and K. Nygaard, "Simula: An Algol Based Simulation Language," Communications of the ACM, vol. 9, no. 9, pp. 671-678, 1966.

....and systematizes a number of known techniques, in an attempt to turn the high availability folklore into a well understood tool. Many techniques have been advocated for improving software dependability, ranging from better software engineering [15] and object oriented programming languages [34] to formal methods that predict verify properties based on a mathematical model of the system [90] Language based methods, such as static analysis [30] detect problems at the source code level. Some programming languages prevent many programming errors by imposing restrictions, such as type ....

O.-J. Dahl and K. Nygaard. Simula---an Algol-based simulation language. Communications of the ACM, 9(9):671--678, Sep 1966.

....or in general purpose code. Continuous simulation languages use different input interfaces, such as block diagrams [2] bond graphs [3] systems dynamics graphs [4] or mathematical equations [5] Object oriented programming originated in the sixties in a discrete simulation language, SIMULA67 [6], which incorporated many of the ideas later included by Alan Kay in the first general purpose objectoriented language, Smalltalk [7] and by Bjarne Stroustrup in C [8] In recent years, object orientation has been added to continuous simulation languages [9] The language we are using to ....

O.J.Dahl, K.Nygaard, "SIMULA - An ALGOL-Based Simulation Language", Comm. ACM, 9:9, 1966, pp.671-678.

....prove the properties of various other common forms. Unfortunately, as illustrated by the linear search example in Section 3.1, the syntax of conventional programming languages is not well suited for the kind of generalization needed in this endeavor. Programming languages descended from Simula [13], such as CLU [30] and Alphard [52] provide a syntax for specifying standard forms, such as linear search, in a more canonical way. However, there are two more fundamental difficulties with using program schemas to represent standard program forms, which Simula and its descendants do not solve. ....

O. J. Dahl and K. Nygaard. SIMULA - An ALGOL-based simulation language. Comm. of the ACM, 9(9):671-678, September 1966.

....increased we observe a better elapsed time performance in SPADES as compared to CSim and Sirescript. This experimentation shows that SPADES is scalable for coarse simulation event. 6 Related Work Many sequential simulation programming languages (SSL) such as GPSS H [15] Sirescript [14] Simula [4] and ModSIM III [1] are available. For developing se quential simulators application specific packages such as SES Workbench [16] AutoMod [13] and ProModel [3] are increasingly used. These packages promote ease of use through user friendly graphical interface for inputting the model, and provide ....

O. J. Dahl and K. Nygaaxd, "SIMULA - An Algol Based Simulation Language," CACM, Vol 9. pp. 671678, 1966.

....the user may choose to explore the data in one or the other way. A third reason for using the cube structure is that it frees the naive user from needing to know how data is stored and retrieved from the database. Much like the object oriented concepts of information hiding and data encapsulation [34], GIS users would see only a black box. They would know about the contents of that box, but would not have to understand the internal representation. Figure 3: The multiple view concept applied to the data cube Cubes over the same geographic extent can be combined by stacking them on top of one ....

O.J. Dahl & K. Nygaard (1966) SIMULA - An Algol-based Simulation Language. Communications of the ACM 9, 671-678.

....Deursen et al. 1996] Maude (Clavel et al. 1996] The algebraic theory of data type specifications use signatures as interfaces. 2.1. 2 Object Oriented Programming In object oriented programming, the notion of a class of objects defines a set of operations that can be applied to those objects (Dahl and Nygaard [1966], Goldberg and Robson [1983] The notion of class in many objectoriented programming languages subsumes the notion of interface, because classes often make a declaration of a set of permitted operations on objects and define the implementation and internal state that accompanies the declaration. ....

Dahl and Nygaard [1966] O J Dahl and K Nygaard. Simula: An ALGOL-based Simulation Language.

....for the genesis and popularization of object oriented programming (OOP) languages (Russel 1995) Craig Hewitt created a new programming concept for actors in his PLANNER (Hewitt, 1969) system. The new concepts for actors (Greif 1975) along with ideas from a new simulation language, Simula (Dahl and Nygaard, 1966), led Alan Kay to create the first complete object oriented language, Smalltalk 76 (Ingalls 1978) At about this same time, Marvin Minksy published his classic paper, proposing frames as basic knowledge representation technique in AI (Minksy 1975) These new ideas led to an explosion of ....

Dahl, O., and Nygaard, K., (1966). SIMULA--An ALGOL-based simulation language.

....could be obtained from the OpenOODB using the technique he came to call PolySPIN. This dissertation builds on the original PolySPIN work, specifying it more precisely and extending its features. 4. 2 Object Oriented Programming Object oriented programming had its inception with Simula [19], a programming language that was rooted in Algol but introduced an important new concept: the object. Objects were typed entities that contained methods (i.e. operations) and variables (attributes, fields) The type of an object was called a class, and in order to define a class, one defined a ....

Dahl, Ole-Johan, and Nygaard, Kristen. Simula---an Algol-based simulation language. Communications of the ACM 9, 9 (Sept. 1966), 671--678.

....Multiconference, SCS, San Francisco, CA, November 07 10, 1993 composition from other models already validated by previous studies. The model reusability is also a strongly recommended feature to satisfy the rapid prototyping constraint. Dahl and Nygaard designed the Simula language 27 years ago (Dahl and Nygaard 1966). They introduced many concepts taken up again by every contemporary object based and objectoriented programming language. The aim of Simula language is to describe directly the systems with a simulation point of view. Since the definition of Simula, the link between object oriented techniques and ....

Dahl, O.; and K. Nygaard. 1966. "SIMULA - An Algol-based Simulation Language." Communications of the ACM 9, no. 9 (Sept.): 671-678.

....such as colors, patterns, intensity, and symbols [Bertin 1983] Varying graphical representation may be used as a fundamental object oriented principle to convey the concept of classes in graphics. Classification is the grouping of several objects with similar properties to a common class [Dahl 1966]. The graphical properties are an effective too] supporting the following two concepts: By using the same graphical representation for several objects at distinct locations, the user is conveyed the information that these objects are similar. By using significantly different representations ....

....of a GIS User Interface. In: GIS LIS 88, pages 665 672, San Antonio, TX, November 1988. Chu 1983] K. C. Chu, J. Fishburn, P. Honeyman, and Y. Lien. VDD A VLSI Design Database System. In: Engineering Design Applications, Annual Meeting, Database Week, pages 25 37, San Jose, CA, May 1983. [Dahl 1966] O. J. Dahl and K. Nygaard. SIMULA An Algol based Simulation Language. Communications of the ACM, 9(9) 671 678, September 1966. Dangermond 1988] J. Dangermond. A Technical Architecture for GIS. In: GIS LIS 88, pages 561 570, San Antonio, TX, November 1988. Dittrich 1986] K. Dittrich. ....

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O.-J. Dahl and K. Nygaard. SIMULA-An Algol-based Simulation Language. Communications of the ACM, 9(9):671-678, September 1966.

....objects that communicate with each other in order to solve the programming task co operatively. Each object is delegated with specific and narrow responsibilities and thus, one advantage of the object oriented (OO) approach consists in its modularity. The OO approach originated in OO programming [5] and gained its first big success with the programming [6] of graphical interfaces. Later, it was generalized to many areas, such as distributed systems [11] and databases [4] software engineering [2] artificial 3 Driver Engine Wheel Door Outage Task Bus Truck Car On duty 0. 1 On ....

O. J. Dahl and K. Nygaard. Simula - an Algol-based Simulation Language. In Communications of the ACM, 9(9), 671-678, 1966.

....implements a protocol by deriving and modifying a subclass. Inheritance from the base class is used to supply predefined code and data structures. The integration of superclass behavior with subclass behavior is done using a generalisation of the method combination techniques used in Simula[DN66, Hor88] This allows the inserting CHAPTER 2. SURVEY 29 of a keyword in the base class to indicate that code implemented in the derived subclass should be executed at this point. Morpheus allows multiple blocks of subclass code to be executed from within the base class. The over riding of default ....

O.J. Dahl and K. Nygaard. Simula -- an Algol-based simulation language. Communications of the ACM, 9(9):671--678, Sept 1966. BIBLIOGRAPHY 183

....providing a consistent process oriented modeling world view. This integration simplifies parallel simulation without engaging the user in the low level parallel activities. Object oriented programming and process interaction simulation modeling are clearly compatible, as evidence by SIMULA [4], the first object oriented programming language. SPaDES places great emphasis on structured modeling and programming in the development of parallel simulators by providing the users with a set of well defined modeling primitives, object classes and a programming template. It adopts a ....

O. J. Dahl and K. Nygaard, "SIMULA - An Algol Based Simulation Language," CACM, Vol 9. pp. 671-678, 1966.

....scratch. 1 Further, once the designer of D has a good understanding of the protected data members of B and a good understanding of how the mem1 The use of the term protected to denote a component that is hidden from the client class but accessible to the derived class was introduced by SIMULA [DN66]. Eiffel does not use the term protected , but in effect, all features of on Eiffel base class are accessible to the derived class (see [Mey88] section 11.5) In the public protected terminology, a feature in Eiffel that is exported is public, and one that is not exported is protected. ber ....

O.J. Dahl and K. Nygaard. Simula - an algol-based simulation language. Communications of the ACM, 9(9):671--678, Sept 1966.

....by a parent class. Subtyping One way in which inheritance can appear in the external interface of a class is subtyping, the rules by which objects of one type (class) are determined to be acceptable in contexts expecting another type (class) In statically typed languages like Trellis Owl, Simula [Dahl66], and C , subtyping rules are of critical importance because they determine the legality of programs. In dynamically typed languages like Common Lisp [Steele84] subtyping rules affect the results of type predicates. Many object oriented languages relate subtyping and inheritance. For example, in ....

O.-J. Dahl and K. Nygaard. Simula An Algol-based Simulation Language. Comm.ACM 9:9 (Sept. 1966), 671-678.

....provide descriptions in the form of comparisons with C. 3.1 Overview and Motivation C is based largely on the C programming language [ISO90, ANS89, KR88, KP90] from which it inherits run time efficiency. C adds to C the notion of classes, a concept that it borrows from Simula 67 [DN66] C is a good language for writing efficient, terse code. However, for a number of reasons, C is not a good programming language for writing abstractions: ffl C data types are only minimally partitioned into interface and implementation. There is simply the definition of the data and the list ....

O. J. Dahl and K. Nygaard. Simula---An Algolbased simulation language. Communications of the ACM, 9:671--678, 1966.

No context found.

K. Nygaard K. and O-J. Dahl. Simula an Algol-based Simulation Language. CACM, 9:671--678, September ####.

No context found.

Dahl, O.-J. and K. Nygaard (1966, September). SIMULA--an ALGOL-based simulation language. Comm. of the ACM 9(9), 671--678.

No context found.

O.-J. Dahl and K. Nygaard. SIMULA--an ALGOL-based simulation language. Commun. ACM, 9(9):671--678, Sept. 1966.

No context found.

Ole-Johan Dahl and Kristen Nygaad. SIMULA---an Algol based simulation language. Communications of the ACM, 9(9):671--678, September 1966.

No context found.

K. Nygaard K. and O-J. Dahl. Simula an Algol-based Simulation Language. CACM, 9:671--678, September ####.

No context found.

Dahl O.-J., Nygaard K., Simula: An Algol-based simulation language. Comm. ACM 9(9), pages 671-678, 1966.

No context found.

DAHL66 Dahl, O-J., Nygaard, K., Simula --- An Algol-Based Simulation Language, Communications of the ACM, Vol. 9, No. 9, September 1966.

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