Unternehmensweites Berechtigungsmanagement

The central coordination of access control management is crucial especially for companies that are engaged in cooperative processes with other companies. Most critical is to respect the security needs that arise with the “opening“ towards other partners.

• The central coordination of access control is indispensable in order to protect the company’s resources.
• If access control management is to be oriented directly towards the corporate goals in contrast to a merely technical view there is a need for extended concepts — like role based access control (RBAC).
• The first software products that make use of the RBAC-concept for a centrally coordinated access control management are available and can be used in practice.

     

An approach to the DIN Kernel Lisp definition

A DIN Kernel LISP Draft (DKLisp) has been developed by DIN as Reaction to Action D1 (N79), short term goal, of ISO WG16. It defines a subset language, as compatible as possible with the ANSICommon-Lisp draft, but also with theEuLisp draft. It combines the most important LISP main stream features in a single, compact, but nevertheless complete language definition, which thereby could be well suited as basis for a short term InternationalLisp Standard. Besides the functional and knowledge processing features, the expressive power of the language is well comparable with contemporary procedural languages, as e.g. C++ (of course without libraries). Important features ofDKLisp are:

to be a “Lisp-1,” but allowing an easy “Lisp-2” transformation;

to be a simple, powerful and standardized educationalLisp;

to omit all features, which are unclean or in heavy discussion;

DKLisp programs run nearly unchanged inCommon-Lisp;

DKLisp contains a simple object and package system;

DKLisp contains those data classes and control structures also common to most modernLisp and non-Lisp languages;

DKLisp offers a simple stream I/O;

DKLisp contains a clean unified hierarchical class/type system;

DKLisp contains the typical “Lisp-features” in an orthogonal way;

DKLisp allows and encourages really small but powerful implementations;

DKLisp comes in levels, so allowing ANSICommon-Lisp to be an extension ofDKLisp level-1.

The present is the second version of the proposal, namely version 1.2, with slight differences with respect to the one sent to ISO. Sources of such changes were the remarks generously sent by many readers of the previous attempt.     

E-Democracy: Eine neue Qualität im demokratischen Entscheidungsprozess

The paper outlines the use of Internet-based services which support the citizen’s participation in democratic decision making. This may concern electronic voting as well as electronic petitions and initiatives.

• Existing or proposed system variants were analyzed in regards to their adherence to democratic principles. The findings show that hardly any of them were able to fulfil the standards required in regards to democratic voting procedures.
• The paper proposes an alternative system for electronic voting via the Internet and discusses its implementation.
• Electronic voting as well as electronic initiatives create new opportunities for the participation of the individual in political decision making due to considerable decreases in transaction costs.

     

Specification and refinement of networks of asynchronously communicating agents using the assumption/commitment paradigm

This paper presents an assumption/commitment specification technique and a refinement calculus for networks of agents communicating asynchronously via unbounded FIFO channels in the tradition of Kahn.

We define two types of assumption/commitment specifications, namely simple and general specifications.

It is shown that semantically, any deterministic agent can be uniquely characterized by a simple specification, and any nondeterministic agent can be uniquely characterized by a general specification.

We define two sets of refinement rules, one for simple specifications and one for general specifications. The rules are Hoare-logic inspired. In particular the feedback rules employ invariants in the style of a traditional while-rule.

Both sets of rules have been proved to be sound and also (semantic) relative complete.

Conversion rules allow the two logics to be combined. This means that general specifications and the rules for general specifications have to be introduced only at the point in a system development where they are really needed.

     

High-speed tools for Global Information Management I. Information processing and retrieval

The general specifications and design for a High-Speed General Information Management System, HSGIMS, to serve as the basis for a Global Information Network are given. Some of the key specifications that have been confirmed in experiments with a prototype of the HSGIMS are:

1. Information (or data) and Question-type (or logical data) independence.
2. Very small bounded search times that are independent of the amount of information that is managed and can be computed exactly.
3. A fool-proof security system that can be used to protect databases against viruses and can also be easily invoked to deny unauthorized access by users.
4. Efficient use of all storage and communications resources.

     

Inventive machine: Second generation

Inventive Machine project is the matter of discussion. The project aims to develop a family of AI systems for intelligent support of all stages of engineering design. Peculiarities of the IM project:

1. deep and comprehensive knowledge base — the theory of inventive problem solving (TIPS)
2. solving complex problems at the level of inventions
3. application in any area of engineering
4. structural prediction of engineering system development

The systems of the second generation are described in detail     

IT sourcing reflections

For more than a decade, the authors have studied the best, worst, and emerging information technology sourcing practices in 543 large and small organizations world-wide. From an initial focus on cost reduction in the early 1990s, the authors found that customers now expect many business advantages from IT outsourcing, including better service, infusion of new technology, transformation of fixed IT budgets to variable IT budgets, improved business processes, and even increased revenues. In short, customers expect IT outsourcing to transform IT functions into lean, dynamic groups that respond quickly to business needs and opportunities. But how do customers actually achieve such business advantage? Customers must become adept at managing four continual processes to successfully exploit IT outsourcing:

• Assess the in-house IT portfolio to determine which activities are best outsourced
• Evaluate market options for the best sourcing models and best suppliers to achieve customer objectives, ranging from simple ASP provision to the creation of customer-supplier joint ventures
• Craft contracts to align customer and supplier expectations and incentives; and
• Continually manage supplier relationships.

Major supplier lessons are also identified, which call for superior supplier integrity in selling, negotiating, and delivering IT services. The overall lesson is that outsourcing can achieve significant results, but it requires new management capabilities.     

Separability and one-way functions

We settle all relativized questions of the relationships between the following five propositions:

• P = NP.
• P = UP.
• P = NP $\cap$ coNP.
• All disjoint pairs of NP sets are P-separable.
• All disjoint pairs of coNP sets are P-separable.

We make the first widespread use of variations of generic oracles to achieve the necessary relativized worlds.     

Kernel language KLND

This paper presents a kernel language KLND on the basis of analysing the kernel languagerequirements of new generation computer systems. These requirements are: the ability ofknow-ledge processing, the parallelism, the elegant mathematical properties of the comput-ation model which is appropriate for working as the basis of the novel architecture design, andthe suitability for writing large scale softwares. The main features of KLND are as follows: 1. several new language concepts. 2. the modularity, 3. the unification of logical and functional programming styles, 4. the exploitation of the parallelism. 5. the introduction of the type concept, 6. the introduction of the storage concept.     

Enhanced qualitative physical reasoning system: Qupras

There are many expert systems that use experimental knowledge for diagnostic analysis and design. However, there are two problems for systems using only experiential knowledge:

1. unexpected problems cannot be solved and
2. acquiring experiential knowledge from human experts is difficult.

To solve these problems, general principles or basic knowledge must be added to expert systems in addition to the experimental knowledge. In response, we previously proposed Qupras (Qualitative physical reasoning system) as a framework for basic knowledge. This system has two knowledge representations, one related to physical laws and the other to objects. By using this knowledge, Qupras reasons about the relations among physical objects, and predicts the next state of a physical phenomenon. Recently, we have improved some of Qupras’ features, and this pater desctibes the following main enhancements:

1. inheritance for representation of objects,
2. new primitive representations to describe discontinuous change, and
3. control features for effective reasoning.

     

Thinking in parallel: four steps to Parlog

If you are familiar with Prolog but not with Parlog then this tutorial is aimed at you. In what follows I attempt to:

? explain the basics of Parlog

? demonstrate that Parlog programs can be powerful and elegant

? discuss the relationship of Parlog to Prolog, and

? identify some resources which will take you further.

These are what I call ‘four steps to Parlog’.     

Strategien für den digitalen Musikmarkt

The recording industry is currently faced with a remarkable decline in revenues and record sales. Paid music services have failed to deliver on their promise of a full-catalog, easy-to-use shopping experience so far, and file sharing platforms are still widely used for obtaining online music. In this context we conducted an empirical study via the Internet with 2.260 participants. The main results are:

1. Neither the installation of copy protection measures nor legal actions taken against users of file sharing platforms seem to be appropriate means to increase sales of CDs and online music.
2. Potential consumers’ willingness to pay is distinctly lower than the prices currently set by the available paid music services.
3. Our study’s results suggest that a price cut for music downloads would lead to increased sales, thus creating benefits for both suppliers and consumers.

     

Powerful Parallel and Symmetric 3D Thinning Schemes Based on Critical Kernels

The main contribution of the present article consists of new 3D parallel and symmetric thinning schemes which have the following qualities:

They are effective and sound, in the sense that they are guaranteed to preserve topology. This guarantee is obtained thanks to a theorem on critical kernels;

They are powerful, in the sense that they remove more points, in one iteration, than any other symmetric parallel thinning scheme;

They are versatile, as conditions for the preservation of geometrical features (e.g., curve extremities or surface borders) are independent of those accounting for topology preservation;

They are efficient: we provide in this article a small set of masks, acting in the grid ?³, that is sufficient, in addition to the classical simple point test, to straightforwardly implement them.

     

Optimal parallel algorithms for rectilinear link-distance problems

We provide optimal parallel solutions to several link-distance problems set in trapezoided rectilinear polygons. All our main parallel algorithms are deterministic and designed to run on the exclusive read exclusive write parallel random access machine (EREW PRAM). LetP be a trapezoided rectilinear simple polygon withn vertices. InO(logn) time usingO(n/logn) processors we can optimally compute:

1. Minimum réctilinear link paths, or shortest paths in theL ₁ metric from any point inP to all vertices ofP.
2. Minimum rectilinear link paths from any segment insideP to all vertices ofP.
3. The rectilinear window (histogram) partition ofP.
4. Both covering radii and vertex intervals for any diagonal ofP.
5. A data structure to support rectilinear link-distance queries between any two points inP (queries can be answered optimally inO(logn) time by uniprocessor).

Our solution to 5 is based on a new linear-time sequential algorithm for this problem which is also provided here. This improves on the previously best-known sequential algorithm for this problem which usedO(n logn) time and space.5 We develop techniques for solving link-distance problems in parallel which are expected to find applications in the design of other parallel computational geometry algorithms. We employ these parallel techniques, for example, to compute (on a CREW PRAM) optimally the link diameter, the link center, and the central diagonal of a rectilinear polygon.     

Ray shooting on triangles in 3-space

We present a uniform approach to problems involving lines in 3-space. This approach is based on mapping lines inR ³ into points and hyperplanes in five-dimensional projective space (Plücker space). We obtain new results on the following problems:

1. Preprocessn triangles so as to answer efficiently the query: “Given a ray, which is the first triangle hit?” (Ray- shooting problem). We discuss the ray-shooting problem for both disjoint and nondisjoint triangles.
2. Construct the intersection of two nonconvex polyhedra in an output sensitive way with asubquadratic overhead term.
3. Construct the arrangement ofn intersecting triangles in 3-space in an output-sensitive way, with asubquadratic overhead term.
4. Efficiently detect the first face hit by any ray in a set of axis-oriented polyhedra.
5. Preprocessn lines (segments) so as to answer efficiently the query “Given two lines, is it possible to move one into the other without crossing any of the initial lines (segments)?” (Isotopy problem). If the movement is possible produce an explicit representation of it.

     

Using collineations to compute motion and structure in an uncalibrated image sequence

We address the well-known problem of estimating the motion and structure of a plane, but in the case where the visual system is not calibrated and in a monocular image-sequence. We first define plane collineations and analyse some of their properties when used to analyse the retinal motion in an uncalibrated image sequence. We show how to relate them to the Euclidean parameters of the scene. In particular, we discuss how to detect and estimate the collineation of the plane at infinity and use this quantity for auto-calibration.

More precisely

- We have been able to elaborate a method to estimate robustly any collineation in the image as soon as at least four projections have been established, especially for points at infinity and the collineation of this virtual infinite plane;

- It is shown that, given at least four points of a stationary plane and two stationary points not on the plane (or equivalently 2 planes) we can compute the focus of expansion;

- A step further, we have defined a bi-ratio of distances for a point with respect to a plane which allows us to analyse not only the relative position of this point with respect to the plane but also quantify this distance;

- Moreover a necessary and sufficient condition for a collineation to correspond to a stationary plane is given in the affine case;

- It is also discussed that when given three views and the plane at infinity, the intrinsics calibration parameters of the camera can be recovered from linear equations.

Robust estimations of collineation and statistical tests are then developed and illustrated by some experimental results.     

A general theory of translation

The concept of a translation is fundamental to any theory of compiling. Formally, atranslation is any set of pairs of words. Classes of finitely describable translations are considered in general, from the point of view of balloon automata [17, 18, 19]. A translation can be defined by atransducer, a device with an input tape and an output terminal. If, with inputx, the stringy appears at the output terminal, then (x, y) is in the translation defined by the transducer. One can also define a translation by a two input taperecognizer. Ifx andy are placed on the two tapes, the recognizer tells if (x, y) is in the defined translation. One can define closed classes of transducers and recognizers by:

1. restricting the way in which infinite storage may be used (pushdown structure, stack structure, etc.),
2. allowing the finite control to be nondeterministic or deterministic,
3. allowing one way or two way motion on the input tapes.

We have some results on classes of translations which can be categorized roughly into three types.

1. Translations defined by certain classes of transducers and recognizers are equivalent.
2. Translations of a given class are sometimes closed under composition and decomposition with a finite memory translation (gsm mapping).
3. A nondeterministically defined translation can be expressed as the composition of a finitely defined translation and a related deterministically defined translation in many cases.

In addition, ifC is a class of translations, then one can write a compiler-compiler to render any translationT inC and only if the following question is solvable: For any translationT inC and stringx, does there exist ay such that (x, y) is inT? We shall show that, in general, the decidability of this question is equivalent to the decidability of one or more questions from automata theory, depending upon the type of devices defining the classC.     

Experiences with software specification and verification using LP,the Larch proof assistant

We sketch a method for deduction-oriented software and system development. The method incorporates formal machine-supported specification and verification as activities in software and systems development. We describe experiences in applying this method. These experiences have been gained by using the LP, the Larch proof assistant, as a tool for a number of small and medium size case studies for the formal development of software and systems. LP is used for the verification of the development steps. These case studies include

? quicksort

? the majority vote problem

? code generation by a compiler and its correctness

? an interactive queue and its refinement into a network.

The developments range over levels of requirement specifications, designs and abstract implementations. The main issues are questions of a development method and how to make good use of a formal tool like LP in a goal-directed way within the development. We further discuss the value of advanced specification techniques, most of which are deliberately not supported by LP and its notation, and their significance in development, Furthermore, we discuss issues of enhancement of a support system like LP and the value and the practicability of using formal techniques such as specification and verification in the development process in practice.