Abstract not found

This paper presents an in-depth examination of the 4.2 Berkeley Software Distribution, Virtual VAX-11 Version (4.2BSD), which is a version of the UNIX’ ” Time-Sharing System. There are notes throughout on 4.3BSD, the forthcoming system from the University of California at Berkeley. We trace the historical development of the UNIX

. In the emerging model of 21st century electronic commerce, a variety of open agent marketplaces will be competing with one another for participants. The most successful marketplaces will be those that provide the best "quality of service" guarantees (in terms of security, fairness, efficiency, etc.), while meeting such challenges as agent heterogeneity, limited trust, and potential for systemic dysfunctions. Civil human societies provide a useful model for designing the infrastructure needed to achieve these guarantees. Successful civil human societies build on well-designed "social contracts", i.e. agreed-upon constraints on agent behavior made in exchange for quality of service assurances backed up by social institutions. Civil Agent Societies can be defined in an analogous way. The objective of our work is to provide tools that help developers systematically explore the space of possible Civil Agent Societies, helping them invent the electronic marketplaces that work b...

The objective of this paper is to contribute to the development of a rigorous discipline for designing trust management mechanisms in online communities. The importance of such a discipline for management science is without question: trust is a precondition for the continued existence of any market and organization in general. Furthermore, several properties of online interaction are challenging the accumulated wisdom of our communities on how to produce trust and require the development of new mechanisms and systems. The paper introduces a mathematical framework for defining trustworthiness and trust. Based on that framework, it defines the related concept of reputation and argues that reputation reporting systems is one of the most promising approaches for producing trust in online communities. It also provides a critical overview of the current state of the art in that area. Following that, it identifies a number of important ways in which unfair buyer and seller behavior can com...

Most current systems are built around a monolithic structure that integrates all the services offered. Such a paradigm has been used for many years and is now proving to have many limitations. This is partly because, with the advent of distributed systems, there is a need to distribute the intelligence and control among applications and network entities. Also due to heterogeneous data or systems that an application has to manage, it costs too much to rebuild the application every time a new service has to be supported. It would be better to add such services while the application is running. This paper attempts to show the benefits of a component­based application against a monolithic one and it introduces a new type of software components, called droplets based on dynamically loadable libraries. Droplets are used to implement selected application services and have the ability to be modified or added to the application while it is running, thus allowing to dynamically modify the application behavior or to extend its functionality at runtime. Finally the paper shows how to design and implement droplet­based applications and demonstrates how the droplet paradigm has been successfully integrated in an existing commercial application.

Psychological and social systems provide us with a natural domain for the study of anticipations because these systems are based on and operate in terms of intentionality. Psychological systems can be expected to contain a model of themselves and their environments; social systems can be strongly anticipatory and therefore co-construct their environments, for example, in techno-economic (co-)evolutions. Using Dubois’s hyper-incursive and incursive formulations of the logistic equation, these two types of systems and their couplings can be simulated. In addition to their structural coupling, psychological and social systems are also coupled by providing meaning reflexively to each other’s meaning-processing. Luhmann’s distinctions among (1) interactions between intentions at the micro-level, (2) organization at the meso-level, and (3) self-organization of the fluxes of meaningful communication at the global level can be modeled and simulated using three hyper-incursive equations. The global level of self-organizing interactions among fluxes of communication is retained at the meso-level of organization. In a knowledge-based economy, these two levels of anticipatory structuration can be expected to propel each other at the supra-individual level.

Abstract. This paper describes the sociological concept of roles as a basis for designing computer-supported community systems (CSCS). The goal is the systematic analysis of roles and role-development from a sociological point of view to enhance socio-technical community-systems. In system theory social structures are expectational structures and roles identify these expectations [22]. Roles explain how actors interact, collaborate and work together to cultivate knowledge exchange. The role concept in social science assumes that people interact with respect to their social roles and take certain roles as a basis for their social interaction and communication. Persons ’ activities and interaction is shaped by roles and vice versa. In contrast, the role concept of computer science focuses on the management of access rights and access control models, and should be clearly differentiated from the sociological understanding. This paper presents the sociological perspective of the term “role ” and explores it in more detail. Then, we present an explorative study of role-development in a web-based learning environment. We conclude by giving examples and making proposals for the technical support of roles. We pay special attention to role-taking, role-making, assigning roles, defining roles and changing roles.

This article deals with the process of formation of norms in societies in which individuals act according to their own cognitive framework under communication. The individuals acquire information from others and interpret it. The way of individual’s action is revised through changing the source of information and reforming the method of interpretation. Through the revising mechanisms, assemblages sharing cognitive frameworks establish. At first individuals adopt the same source of information and then arrange the shared cognitive framework. The assemblage are considered as groups with common norms, since the same cognitive framework gives actions coherency. In the process of formation the two revising mechanisms function in turn. The intensity of interaction among individuals affects the period to build norms and the size of groups sharing norms. The size develops under strong interaction but the period comes to long. The dependency of average size of norms on the strength is a power.

Protection is the mechanism employed by operating systems to control access to resources. Object encapsulation in object-based systems requires control of access to every object. The incremental definition of objects through inheritance and type hierarchies is an important aspect of object-oriented systems. This dissertation examines the relationship between protection and object-oriented hierarchies. Splitting object-oriented hierarchies across protection boundaries is particularly attractive for the purposes of providing a uniform programming model to objectoriented applications and for implementing a minimal object-oriented kernel. After surveying current research and providing a background for discussion, this dissertation presents a detailed analysis of the issues relating to splitting object-oriented hierarchies across protection boundaries. The analysis is independent of language, operating system, and protection model. The analysis reveals the precautions that must be taken to guard against protection violations. The analysis also shows that in the general case an object must be able to be split across the protection boundaries, and that the child portion of the object should delegate or forward unrecognized method calls to the parent portion of the object on the other side of the boundary.

An undo facility is an essential component of most interactive applications. In current operating system shells, whether textual or graphical, such facilities are typically very poor. Algorithms are presented for adding a recovery mechanism to a shell which allows previous commands to be selectively undone and redone, and previous versions of files to be recovered. The recovery mechanism involves making the shell control resources in a more intelligent way. Programs are run under greater control, with the shell monitoring and analysing their resource requests. This provides better high level information to the shell and, for example, provides techniques to prevent foreign or untrustworthy programs from doing any damage, and to reduce problems with conflicting resource requests from concurrent programs. A prototype implementation has been implemented to investigate the convenience and natural feel of these facilities. 1 Introduction A recovery ability is a crucial feature that many int...