Разработка интерактивной моделирующей системы технологии низкотемпературной сепарации газа

We present a study of J ψ meson production in collisions of 26.7 GeV electrons with 820 GeV protons, performed with the H1-detector at the HERA collider at DESY. The J ψ mesons are detected via their leptonic decays both to electrons and muons. Requiring exactly two particles in the detector, a cross section of σ(ep → J ψ X) = (8.8±2.0±2.2) nb is determined for 30 GeV ≤ W γp ≤ 180 GeV and Q 2 ≲ 4 GeV 2 . Using the flux of quasi-real photons with Q 2 ≲ 4 GeV 2 , a total production cross section of σ ( γp → J / ψX ) = (56±13±14) nb is derived at an average W γp =90 GeV. The distribution of the squared momentum transfer t from the proton to the J ψ can be fitted using an exponential exp(− b ∥ t ∥) below a ∥ t ∥ of 0.75 GeV 2 yielding a slope parameter of b = (4.7±1.9) GeV −2

Maintenance of Object-oriented Systems during Structural Evolution *

ion of common parts and distribution of common parts are extended to apply to syntax edges as well as attribute edges. The only additional complexity is that abstraction of common parts to a superclass is restricted so that the ordering of parts at each immediate subclass cannot be changed. If there is a set of classes that have more than one part in common, but the common parts are ordered differently in the individual classes, then it is not possible to abstract all of the common parts. The object-preserving transformations for class graphs are as follows: ffl Renumbering of parts. Any set of attribute and syntax edges in a class graph may be renumbered as long as the ordering of parts (including inherited parts) remains unchanged for each class. ffl Abstraction of common parts. If all of the immediate subclasses of class C have the same part, that part can be moved up the inheritance hierarchy so that each of the subclasses will inherit the part from C, rather than duplicating the..

Object-Preserving Class Transformations

Reorganization of classes for object-oriented programming and object-oriented database design has recently received considerable attention in the literature. In this paper a small set of primitive transformations is presented which forms an orthogonal basis for object-preserving class reorganizations. This set is proven to be correct, complete, and minimal. The primitive transformations help form a theoretical basis for class organization and are a powerful tool for reasoning about particular organizations

Managing the Evolution of Object-Oriented Systems

ii Class organizations (schemas) evolve over the life cycle of object-oriented systems for avariety of reasons. This issue has recently been a subject of increasing attention in the literature of both object-oriented languages and object-oriented database systems. One of the most common forms of evolution involves the extension of an existing system by addition of new classes of objects or the addition of attributes to the original objects. Sometimes class structures are reorganized even when the set of objects is unchanged. In this case the reorganization might represent an optimization of the system, or just a change in the users ' perspective. At the other extreme, a class reorganization might re ect not only the extension and reclassi cation of existing objects, but also structural changes (other than addition of attributes) in the original objects. This work provides a mathematical treatment of a calculus of class transformations. Three kinds of transformations that commonly occur in the evolution of class structures are considered: object-extending, object-preserving, and language-preserving. For each kind of transformation, methods for automating the maintenance of systems based on the evolving class structure are discussed. The language-preserving transformations are a special case of transformations that change the structure of existing objects. If an object schema is decorated with concrete syntax, it de nes not only a class structure, but also a language for describing the objects. When two schemas de ne the same language but di erent classes, the language may be used to guide the discovery of analogies between the classes. The resulting analogies may then be used to transport functionality between domains. iii Acknowledgments Iwould like to thank my advisor, Karl Lieberherr, for his generous support, guidance, and feedback. I would also like to thank my wife, Vickie, for her constant encouragement and understanding without which thiswork would not have been possible. i

Maintainance of object-oriented systems during structural schema evolution

We have previously developed a mathematical treatment of a calculus for class transformations that preserve or extend a set of objects. Methods for automating the maintenance of structural and behavioral consistency in systems based on evolving class structures have been provided for the object-preserving and object-extending transformations. This work extends the calculus of class transformations to include certain transformations that reflect not only the extension and reclassification of existing objects, but also structural changes (other than addition of attributes) in the original objects. Language-preserving transformations are a special case of transformations that change the structure of existing objects. If an object schema is decorated with concrete syntax, it defines not only a class structure, but also a language for describing the objects. When two schemas define the same language but different classes, the language may be used to guide the transportation of functionality between domains. The languagepreserving transformations defined here form the basis of a complete transformation system for a subset of class graphs powerful enough to express the regula

Maintenance of Object-oriented Systems during Structural Evolution

ion of common parts and distribution of common parts are extended to apply to syntax edges as well as attribute edges. The only additional complexity is that abstraction of common parts to a superclass is restricted so that the ordering of parts at each immediate subclass cannot be changed. If there is a set of classes that have more than one part in common, but the common parts are ordered differently in the individual classes, then it is not possible to abstract all of the common parts. The object-preserving transformations for class graphs are as follows: ffl Renumbering of parts. Any set of attribute and syntax edges in a class graph may be renumbered as long as the ordering of parts (including inherited parts) remains unchanged for each class. ffl Abstraction of common parts. If all of the immediate subclasses of class C have the same part, that part can be moved up the inheritance hierarchy so that each of the subclasses will inherit the part from C, rather than duplicating the..

Maintaining Behavioral Consistency during Schema Evolution

We examine the problem of how to ensure behavioral consistency of an object-oriented system after its schema has been updated. The problem is viewed from the perspective of both the strongly typed and the untyped language model. Solutions are compared in both models using C++ and CLOS as examples. 1 Introduction Schema evolution and transformations have recently received increasing attention in the literature in both the area of object-oriented languages and especially in the area of object-oriented database systems: [Opd92, Ber92, Ber91, Cas91, CPLZ91, DZ91, Bar91, LH90, AH88, BKKK87, PS87, SZ86]. Most of this work has been done from the object-oriented database point of view where the focus is naturally on the structural, rather than behavioral, aspects of the evolving schema. Systems such as ORION [BKKK87], GemStone [PS87], and OTGen [LH90] guarantee the correctness of the performed schema changes and reflect the impact on the persistent instances in the database (structural consis..