Graph-Based Customizationbject-oriented programs are easier to extend than programs that are not written in an object-oriented style, but object-oriented programs are still very rigid and difficult to adapt and maintain. A key feature of most popular approaches to objectoriented programming is that methods are attached to classes-C + +, Smalltalk, Eiffel, Beta-or to groups of classes-CLOS. This feature is both a blessing and curse. On the brighter side, attaching methods to classes is at the core of 1) objects being able to receive messages, 2) different classes of objects responding differently to a given message, and 3) the ability to define standard protocols. On the darker side, by explicitly attaching every single method to a specific class, the details of the class structure are encoded into the program unnecessarily. This leads to programs that are difficult to evolve and maintain. In other words, today's object-oriented programs often contain more redundant application-specific information than is necessary, thus limiting their reusability. Does this mean we have to either take the curse in order to enjoy the blessing or give up the blessing altogether? Analyzing the problem we realize that not all is lost. What we need is to be able to specify only those elements that are essential to an object-oriented program and then specify them in a way that cJlows them to adapt to new environments.What do we mean by specifying only those elements-classes and methodsthat are essential to an object-oriented program? In [16], Wilde and Huitt point out: "There is a general impression that object-oriented programs may tend to be structured rather differently than conventional programs. For many tasks very brief methods may be written that simply 'pass through' a message to another method with very little processing." Such "traversal, pass through" methods we regard as nonessential. But more important, we intend to focus on classes and methods that are essential not only to a particular application but also potentially to a family of related applications.How can we identify such generic classes and methods? Consider the following "paradox of the inventor" posed by mathematician George Folya [12]. He observed that it is often easier to solve a more general problem than the one at hand and then to use the solution of the general problem to solve the specific problem. The hard work consists of finding the appropriate generalization. Polya uses the following example to demonstrate the technique. O ACM 0002-0782/94/().Mi(i s , Mi COMMUIHMTIOHS OP THB aCM May t994/Vol.37, Ni>.S lOt

In service-oriented computing, multiple services often exist to perform similar functions. In these situations, it is essential to have good ways for qualitatively ranking the services. In this paper, we present a new ranking method, ServiceRank, which considers quality of service aspects (such as response time and availability) as well as social perspectives of services (such as how they invoke each other via service composition). With this new ranking method, a service which provides good quality of service and is invoked more frequently by others is more trusted by the community and will be assigned a higher rank. ServiceRank has been implemented on SOAlive, a platform for creating and managing services and situational applications. We present experimental results which show noticeable differences between the quality of service of commonly used mapping services on the Web. We also demonstrate properties of ServiceRank by simulated experiments and analyze its performance on SOAlive.

Abstract-Service network analysis is an essential aspect of web service discovery, search, mining and recommendation. Many popular web service networks are content-rich in terms of heterogeneous types of entities, attributes and links. A main challenge for ranking services is how to incorporate multiple complex and heterogeneous factors, such as service attributes, relationships between services, relationships between services and service providers or service consumers, into the design of service ranking functions. In this paper, we model services, attributes, and the associated entities, such as providers, consumers, by a heterogeneous service network. We propose a unified neighborhood random walk distance measure, which integrates various types of links and vertex attributes by a local optimal weight assignment. Based on this unified distance measure, a reinforcement algorithm, ServiceRank, is provided to tightly integrate ranking and clustering by mutually and simultaneously enhancing each other such that the performance of both can be improved. An additional clustering matching strategy is proposed to efficiently align clusters from different types of objects. Our extensive evaluation on both synthetic and real service networks demonstrates the effectiveness of ServiceRank in terms of the quality of both clustering and ranking among multiple types of entity, link and attribute similarities in a service network.

Abstract. SOAlive aims at providing a community-centric, hosted environment and, in particular, at simplifying the description and discovery of situational enterprise services via a service catalog. We argue that a service community has an impact not only on users and services, but also on the environment itself. Specifically, our position is that a service catalog adds value to users, and is itself enriched, by its incorporation into a community-centric service hosting environment. In addition, analyses of web services directories suggest that a catalog service for enterprise services can be better provided by using a simpler content model that better fits REST, taking advantage of collaborative practices to annotate catalog entries with informal semantic descriptions via tagging, providing a mechanism for embedding invocations of discovered services, and allowing syntactic descriptions to be refined via usage monitoring. The SOAlive service catalog defines a flexible content model, a discovery function that navigates the cloud of tag annotations associated with services in a Web 2.0 fashion, and a service description refinement function that allows the actual use of a service to refine the service description stored in the catalog.

Guidelines for the enterprise.