R.J. Wieringa, W. de Jonge, and P. Spruit. Using Dynamic Classes and Role Classes to Model Object Migration. In Theory and Practise of Object Systems, 1(1), pages 61-83, 1995.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....a model may learn over time: A model we do not understand at first sight may appear clear and even intuitive after we have studied it. There is a growing awareness of the problems related to the evaluation of information models. Most of the corresponding publications ( KrLi95] Lin94] MoSh94] [Wie95]) have in common that they consider the evaluation of models to be a multi faceted problem. It requires to take into account the different conceptual and professional preferences of those who use a model. It should also take into account the represented domain and how it might change over. Against ....

Wieringa R.J., Jonge W. de, Spruit P.A.: Using Dynamic Classes and Role Classes to Model Object Migration. In: Theory and Practice of Object Systems, 1, 1995, pp. 61-83

....that of Man and Woman. The interest of partitions lies in their simplicity, expressiveness and generality (since specializations and generalizations can be transformed into partitions) Often it is easier to develop, analyze and reason about conceptual schemas, when only partitions are considered [21, 4, 25, 13]. However, partitions have not been studied in the literature on schema evolution. Since the early works of Orion [3] there has been a lot of work related to the evolution of specializations (or generalizations or subclass superclass relationships) but, as far as we know, there are not published ....

# Wieringa, R.; de Jonge, W.; Spruit, P. Using Dynamic Classes and Role Classes to Model Object Migration, TPOS, Vol 1(1), pp. 61-83.

....the implementation in ConceptBase of the attribute and value derivation mechanisms of our part model. Second, we are studying the metaclass formalization and implementation of other semantic links for object models. They include binary and n ary relationships, aggregated relationships, roles [31], ownership [15] and materialization [7, 29] This will help define common metalevel specifications for semantic link support and enhancements to object oriented models. Acknowledgements. M. Dahchour wishes to thank all the colleagues in the ConceptBase discussion forum, particularly Manfred ....

R. Wieringa, W. De Jonge, and P. Spruit. Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1(1):61--83, 1995.

....Guarino, a role is meaningful only in the context of a relationship. Although a fundamental characteristic, many definitions of the role concept do not consider it, so that the states or phases of an object are equally regarded as their roles. 3. An object may play different roles simultaneously [41,45,52,54,55,75,76]. This is one of the most broadly accepted properties of the role concept. Because a role is usually regarded as a type (item 1) it amounts to the multiple classification of objects. 4. An object may play the same role several times, simultaneously [41,52,55,75,76] This is an equally ....

....roles simultaneously [41,45,52,54,55,75,76] This is one of the most broadly accepted properties of the role concept. Because a role is usually regarded as a type (item 1) it amounts to the multiple classification of objects. 4. An object may play the same role several times, simultaneously [41,52,55,75,76]. This is an equally fundamental finding, a frequent example of which being an employee holding several employments. Unlike with different roles, however, it does not correspond to multiple classification. The main reason to distinguish multiple occurrences in the same role is that each occurrence ....

[Article contains additional citation context not shown here]

R. Wieringa, W. de Jonge, P. Spruit, Using dynamic classes and role classes to model object migration, Theory and Practice of Object Systems 1 (1) (1995) 61 83.

....But normally such dependencies are likely to occur, if one tears apart classes according to different aspects. For example, the classes TrayTransversalFlow and TrayVariableEnthalpy both contain an attribute named enthalpy liquid. In the more commonly know Person with roles scenario (cf. WdJS95, GSR96, WCL97] such dependencies also exist: The role married is mutual exclusive with the role catholic priest , the role in jail restricts the number of available employment roles quite a bit and, the role lecturer requires the role Ph.D. Also the attribute works at of a ....

....We rst discuss the closest approach, classes with roles, in some depth, then brie y summarize other related techniques. 4.1 Aspects versus Roles Roles represent a mechanism to structurally restrict multiple instantiation similar to aspects. Roles have been described by di erent authors [WdJS95, GSR96, AGO95, RS91] to name just a few in many variations and under di erent names. These variations di er in whether roles have an own object identity, whether the same role can be instantiated more than once per object, whether the role space is partitioned, which method lookup strategy is ....

[Article contains additional citation context not shown here]

R.J. Wieringa, W. de Jonge, and P.A. Spruit. Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1(1):61-83, 1995.

....object observes it surroundings in order to decide on a role to play. The authors of [17] also focus on roles played by an object. They discuss classes offering different behavior through separate interfaces. The caller is able to decide which interface to use, which in turn influences behavior. [18] analyses how roles and classes impact on modeling issues. They cover a number of approaches to implementing roles, including the delegational approach we have chosen. The Objectory Process supports the concept of architectural views [6] which are related to our class graph views. Architecture is ....

....information from the correspondence to set up translation functions. However, this also allows instances of global classes (like java.lang.String) and primitives (like int) pass unchanged across the boundary. Translating from the view to the real class graph is trivial; the played by relationship [18] is implemented as an instance variable on the view object. To find the host object of a view object, one needs merely to look there. Translating back is harder. We require that each host class that wants to participate in role playing must be primed to do so. This priming includes adding a ....

R. Wieringa, W. de Jonge, and P. Spruit. Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1, 1995.

....Toxic Material Non toxic Material Highly Toxic Material Location Produces Factory Name Temperature Quantity Waste Material Inhabitants Distance Area Position Safe Area Dangerous Area Critical Area Figure 5. Database schema of our Pollution Control example et al. in [34], should be employed. 5.3 Pollution Control Consider the hierarchy in Figure 5, representing information about factories and their wastes, to control the safety with respect to pollution in certain areas. In particular, for each factory its location is recorded, as well as the set of wastes it ....

R. Wieringa, W. de Jonge, and P. Spruit. Using Dynamic Classes and Role Classes to Model Object Migration. Theory and Practice of Object Systems, 1(1):61--83, Spring 1995. Special Issue: Selected Papers from ECOOP `94. OBJECT EVOLUTION IN OBJECT DATABASES 33

....a rather complicated semantic model, due to the need of combining F structures with path structures. Also, it is not clear how to handle more sophisticated dynamic features, such as role dynamics and object migration, which have been recognized as important issues in the object oriented paradigm [ABGO93, RS90, Su91, WdS95]. 2 XY Stratification and Nondeterminism The basic tool used in this paper is a fragment of the LDL language, consisting of Datalog augmented with a non deterministic choice construct [GPSZ91] and a form of stratification called XY stratification [AOTZ93] Choice goals are used to ....

R. Wieringa, W. de Jonge, and P. Spruit. Using Dynamic Classes and Role Classes to Model Object Migration. Theory and Practice of Object Systems, 1(1):173--196, 1995.

....typed functional nature of Fibonacci. In Degas multiple inheritance is not needed, since addons need no information about other addons. There is no treatment of rules or time in both Aspects and Fibonacci. An extensive conceptual study and formalisation of objects with roles can be found in [44]. Here it is observed that there are static classes, dynamic classes and roles. Objects cannot migrate between static classes. Hence, these are equivalent to the classes in Degas. Dynamic classes are based on dynamic partitions of a static object class. Objects can migrate between dynamic classes, ....

....class migration is specified in the lifecycle of an object. Migration is achieved through the gain and loss of addons. Roles are tied to relations. When engaging in a relation, an object will gain the addon that specifies its role in the relation. The main difference between the analysis in [44] and Degas is, that Degas only distinguishes between inherent and transient capabilities of an object. 12 Related Work Temporal Databases If we look at the temporal functionality offered by Degas, we see that the OODAPLEX model offers the same functionality in the temporal sense. In addition it ....

Roel Wieringa, Wiebren de Jonge, and Paul Spruit. Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1(1):61-83, 1995.

.... 29; 41; 43; 49; 55] This is a dynamic property of the role concept that comes close to object migration or dynamic (re)classification [46; 69] However, the two are not necessarily the same; for example, Wieringa et al. make an explicit distinction between dynamic classification and role playing [75]. 2 Note that, to a certain extent, Guarino s criteria parallel Lodwick s definition of appelative and proper nouns: murderer and murdered are related to each other through a murder, and they lack semantic rigidity; they are roles. Man or beast, on the other hand, are rigid; they are natural ....

....of the objects playing them (delegation) 16; 41] 14. An object and its roles share identity [3; 29; 41; 55] In the object oriented world this entails that an object and its roles are the same, a condition that has been paraphrased as a role is a mask that an object can wear [8] Not in [75]. 15. An object and its roles have different identities [75] This view, which is quite singular, is a tribute to the so called counting problem. It refers to the situation in which instances counted in their roles yield a greater number than the same instances counted by the objects playing ....

[Article contains additional citation context not shown here]

R Wieringa, W de Jonge, P Spruit "Using dynamic classes and role classes to model object migration" Theory and Practice of Object Systems 1:1 (1995) 61--83.

....and damages its reusability. Using Java s standard Date class, the following would be preferable. Date Today( return Java s Date for Today 4. Dynamic Personalities Making personalities attachable and detachable at runtime allows us to solve the classic object migration problem [21]. For example, we might have an object of class Person that gets hired by a company, and thus needs to become an object of class Employee, and later gets promoted, and thus needs to be of type Manager. Common workarounds for this problem include reclassification (i.e. reinstantiating an object of ....

Wieringa, R., de Jonge, W., Spruit, P. Using Dynamic Classes and Role Classes to Model Object Migration. Theory and Practice of Object Systems, 1995

....are likely to occur, if one tears apart classes according to different aspects. In the hierarchy of figure 2 for example the classes TrayTransversalFlow and TrayVariableEnthalpy both contain an attribute named enthalpy liquid. In the more commonly know Person with roles scenario (cf. [WdJS95, GSR96, WCL97]) such dependencies also exist: The role married is mutual exclusive with the role catholic priest , the role in jail 5 Since aspects are abstract classes and therefore may not be instantiated directly, the object must instantiate a subclass of each mandatory aspect. 6 3.2. Modeling ....

....The development of a type checking algorithm and the evaluation of performance are currently under way. 4 Related Work 4.1 Aspects versus roles Roles represent a mechanism to structurally restrict multiple instantiation similar to aspects. Roles have been described by different authors [WdJS95, GSR96, AGO95, RS91] to name just a few in many variations and under different names. These variations differ in whether roles have an own object identity, whether the same role can be instantiated more than once per object, whether the role space is partitioned, which method lookup strategy is used, whether ....

[Article contains additional citation context not shown here]

R.J. Wieringa, W. de Jonge, and P.A. Spruit. Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1(1):61--83, 1995.

....dealt with separate frameworks. On the contrary, we argue in this paper that Datalog provides a flexible uniform framework, and moreover enables us to handle sophisticated dynamic features, such as roledynamics and object migration, widely recognized as key issues in the objectoriented paradigm [3, 21]. Semistructured Data Management. To illustrate the expressiveness of the ADOOD, we conclude this paper by presenting some examples from the management of semistructured information, such as that available on the web. In particular, we point out how the mechanisms of ADOOD allow querying and ....

R. Wieringa, W. de Jonge, and P. Spruit. Using Dynamic Classes and Role Classes to Model Object Migration. Theory and Practice of Object Systems, 1(1):173--196, 1995.

....interaction between objects was synchronous. Similarly, America and de Boer (1996) proposed an exogenous logical system based on the synchronous CSP primitives for dealing with object creation and reconfiguration in a subset of POOL, sticking to the specific programming formalism in this way. Wieringa et al. 1995), Parisi Presicce and Pierantonio (1994) studied naming, roles and classes, although the treatment of interaction and dynamic reconfiguration was not addressed. The actor model seems to demand a specific logical system to support the design of open distributed systems the meaning of the actor ....

....by the action symbols in Figure 1. y We usually consider that the enumerated constants are all different from each other. z Because actors may self address requests, Gamma e and Gamma l should not be disjoint in general. Carlos H. C. Duarte 6 As is usual in a proof theoretic approach, cf. Wieringa et al. 1995), we extend signatures with new logical symbols. The situation here resembles the use of hidden symbols in algebraic specifications (Ehrig and Mahr 1985) Therein, the specifier may need to use an externally unavailable language to specify complex data types. Herein, we use a simpler language to ....

R. J. Wieringa, W. de Jonge, and P. Spruit (1995). Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems 1 (1) 61--83.

....dealt with in separate frameworks. On the contrary, we argue in [10] that Datalog provides a flexible uniform framework, and moreover enables us to handle sophisticated dynamic features, such as roledynamics and object migration, widely recognized as key issues in the object oriented paradigm [5, 19, 21]. We argue that the achieved high degree of expressiveness and flexibility is made possible by the integration of the object oriented model with deductive and active rules in a coherent overall framework. In [3, 1] a model for Web computability is presented. Such a model can be seen, to a greater ....

R. Wieringa, W. de Jonge, and P. Spruit. Using Dynamic Classes and Role Classes to Model Object Migration. Theory and Practice of Object Systems, 1(1):173--196, 1995.

....to be atomic. OOA rightly allows objects to migrate between classes. This has an important methodological consequence that is however not remarked by Shlaer and Mellor, viz. that in object migration, an instance may become a member of a subclass without creating an instance of a superclass [56]. For example, if an instance of MIXING TANK migrates from UNASSIGNED to ASSIGNED, then the set of existing instances of UNASSIGNED is decreased by one without a change in the set of existing instances of MIXING TANK. Contrast this with the non migratory case: If the partitioning of TANK into ....

....is never removed from this extension. ffl Attributes are interpreted as updatable functions. In different states of the system, one attribute can be interpreted as different functions. Finally, we sketch a formalization of subclassing. This formalization is discussed in detail by Wieringa et al. [56]. If objects cannot migrate between subclasses of a certain class C, then the specialization of C can be represented by a partial ordering of identifier types. For example, if figure 2 represents a static partitioning of TANK, then the identifier type of STORAGE TANK is a subtype of the identifier ....

[Article contains additional citation context not shown here]

R.J. Wieringa, W. de Jonge, and P.A. Spruit. Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1(1):61--83, 1995.

....that they know. ffl Assuming that notation X is used in practice, we can identify areas not covered by the formal notation but useful in practice. This gives direction to future research in formal notations. In previous work, we have analyzed the OMT method using TROLL as means of analysis [27, 47]. In this report, we continue our research by analyzing the notations used in the Shlaer Mellor method of object oriented analysis (OOA) 37, 39] One of the reasons for this choice is that the Shlaer Mellor method is, next to OMT, one of the more popular object oriented methods. In addition, it ....

....there is no other precondition for the success of refuse check(a; m) this is also a sufficient precondition for success. These assumptions are not expressible as first order axioms. One way around this is to generate frame and qualification axioms for each individual specification automatically [47]. Other ways of dealing with this are currently under study [12] Figure 4.14 specifies the transactions of the account system. The following remarks are in order: ffl The LCM specification formalizes the transaction decomposition table. Transaction CFDs and transaction DFDs are not formalized, ....

[Article contains additional citation context not shown here]

R.J. Wieringa, W. de Jonge, and P.A. Spruit. Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1(1):61--83, 1995.

....The intention we have in this paper is to outline a semantics that should be appropriate for higher levels of software modeling. 1. 3 Comparison with other work This paper continues research undertaken earlier on the formalization of visual objectoriented software specification techniques [33, 34, 35, 36]. It contains a summary of the essentials of this formalization, sufficient to formalize ultra LUML. The additions to this earlier work consist of, first, a different version of dynamic logic, that includes a simple form of parallelism with a transition system semantics. Second, we now give a ....

....is standard. The two level semantics of action terms allows us to reason about equality of action terms. This motivates the following inference rule, which is sound with respect to the semantics given above: a 1 = a 2 [a 1 ]OE [a 2 ]OE : Details and other inference rules are given elsewhere [36, 35]. 2.2.3 Specifications A specification Spec = Sig; Phi) consists of a dynamic logic signature Sig and a finite subset Phi ae L Sig;X that contains the following classes of axioms. ffl ADT axioms for the abstract data types. These are formulas in L Sig Eq ;X . ffl Static constraints are ....

[Article contains additional citation context not shown here]

R.J. Wieringa, W. de Jonge, and P.A. Spruit. Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1(1):61--83, 1995. ftp://ftp.cs.vu.nl/pub/roelw/95-DynamicClassesAndRoles.ps.Z. ftp://ftp.cs.vu.nl/pub/roelw/95DynamicClassesAndRoles. ps.Z.

....This list suffices to give an impression of the connection rules. There are two ways to make this more precise, by means of formalization and by means of a metamodel. To formalize the diagrams and their links, a formalization based upon order sorted dynamic logic and process algebra will be used [54, 64, 63]. This is particularly important for the rules in the above list that contain the word consistent . Definition of a metamodel is ongoing work, which is part of the specification and implementation of the TCM software tool [60] Table 3 does not define links for the subject domain model (a class ....

....the techniques discussed in this paper. Validation of another kind takes place by providing a formal semantics to the techniques in TRADE. A formal semantics of a combination of objects with behavior and communication, based on order sorted dynamic logic and process algebra, has been given earlier [54, 64, 63]. Current work concentrates on declarative and operational semantics of behavior specifications so as to provide an execution semantics for STDs in TCM [60] The methodological role of this is to strengthen the tools in TRADE by making their meaning and interconnections explicit. Our hope is that ....

R.J. Wieringa, W. de Jonge, and P.A. Spruit. Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1(1):61-- 83, 1995. ftp://ftp.cs.vu.nl/pub/roelw/95-DynamicClassesAndRoles.ps.Z..

No context found.

R.J. Wieringa, W. de Jonge, and P. Spruit. Using Dynamic Classes and Role Classes to Model Object Migration. In Theory and Practise of Object Systems, 1(1), pages 61-83, 1995.

No context found.

Wieringa, R.J. de Jonge, W., Spruit, P.A.: Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1(1) (1995) 61-83

No context found.

R.J. Wieringa, W. de Jonge, and P.A. Spruit. Using dynamic classes and role classes to model object migration. Theory and Practice of Object Systems, 1(1):61-- 83, 1995. 181, 252

No context found.

Wieringa R.J., Jonge W. de, Spruit P.A.: Using Dynamic Classes and Role Classes to Model Object Migration. In: Theory and Practice of Object Systems, 1,

No context found.

Roel Wieringa, Wiebren de Jonge, and Paul Spruit. Using dynamic classes and role classes to model object migration. Teory and Practice of Object Systems, 1(1):61--83, 1995.

No context found.

Wieringa, R., de Jonge, W., and Spruit, P. "Using Dynamic Classes and Role Classes to Model Object Migration." Theory and Practice of Object-Oriented Systems 1, 1: 61-84.

First 50 documents

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC