Mehmet Altinel

Damia: data mashups for intranet applications

Increasingly large numbers of situational applications are being created by enterprise business users as a by-product of solving day-to-day problems. In efforts to address the demand for such applications, corporate IT is moving toward Web 2.0 architectures. In particular, the corporate intranet is evolving into a platform of readily accessible data and services where communities of business users can assemble and deploy situational applications. Damia is a web style data integration platform being developed to address the data problem presented by such applications, which often access and combine data from a variety of sources. Damia allows business users to quickly and easily create data mashups that combine data from desktop, web, and traditional IT sources into feeds that can be consumed by AJAX, and other types of web applications. This paper describes the key features and design of Damias data integration engine, which has been packaged with Mashup Hub, an enterprise feed server currently available for download on IBM alphaWorks. Mashup Hub exposes Damias data integration capabilities in the form of a service that allows users to create hosted data mashups.

DBCache: middle-tier database caching for highly scalable e-business architectures

Multi-tier infrastructures have become common practice for implementing high volume web sites. Such infrastructures typically contain TCP load balancers, HTTP servers, application servers, transaction-processing monitors, and databases. Caching has been widely used at different layers of the infrastructure stack to improve scalability and response time of e-business applications. The majority of existing caching mechanisms target only static HTML pages or page fragments. However, as web applications become more dynamic through increased personalization, these caching techniques turn out to be less useful. Consequently, as more application requests result in increased querying and updating of backend database servers, scalability limits are often reached.

Design and Implementation of a Distributed Workflow Management System: METUFlow

Workflows are activities involving the coordinated execution of multiple tasks performed by different processing entities, mostly in distributed heterogeneous environments which are very common in enterprises of even moderate complexity. Centralized workflow systems fall short to meet the demands of such environments.

DBCache: database caching for web application servers

Many e-Business applications today are being developed and deployed on multi-tier environments involving browser-based clients, web application servers and backend databases. The dynamic nature of these applications necessitates generating web pages on-demand, making middle-tier database caching an effective approach to achieve high scalability and performance [3]. In the DBCache project, we are incorporating a database cache feature in DB2 UDB by modifying the engine code and leveraging existing federated database functionality. This allows us to take advantage of DB2s sophisticated distributed query processing power for database caching. As a result, the user queries can be executed at either the local database cache or the remote backend server, or more importantly, the query can be partitioned and then distributed to both databases for cost optimum execution.DBCache also includes a cache initialization component that takes a backend database schema and SQL queries in the workload, and generates a middle-tier database schema for the cache. We have implemented an initial prototype of the system that supports table level caching. As DB2s functionality is extended, we will be able to support subtable level caching, XML data caching and caching of execution results of web services.

METU object-oriented DBMS

METU Object-Oriented DBMS1 includes the implementation of a database kernel, an object-oriented SQL-like language and a graphical user interface. Kernel functions are divided between a SQL Interpreter and a C++ compiler. Thus the interpretation of functions are avoided increasing the efficiency of the system. The compiled by C++ functions are used by the system through the Function Manager. The system is realized on Exodus Storage Manager (ESM), thus exploiting some of the kernel functions readily provided by ESM. The additional functions provided by the MOOD kernel are the optimization and interpretation of SQL statements, dynamic linking of functions, and catalog management.

Highly personalized information delivery to mobile clients

The inherent limitations of mobile devices necessitate information to be delivered to mobile clients to be highly personalized according to their profiles. This information may be coming from a variety of resources like Web servers, company intranets, email servers. A critical issue for such systems is scalability, that is, the performance of the system should be in acceptable limits when the number of users increases dramatically. Another important issue is being able to express highly personalized information in the user profiles, which requires a querying power as that of SQL on relational databases. Finally, the results should be customized according to user needs, preferences and the mark up language of their mobile device. Since the queries will be executed on the documents fetched over the Internet, it is natural to expect the documents to be XML documents.This paper describes an architecture for mobile network operators to deliver highly personalized information from XML resources to mobile clients. To achieve high scalability in this architecture, we index the user profiles rather than the documents because of the excessively large number of profiles expected in the system. In this way all queries that apply to a document at a given time are executed in parallel through a finite state machine (FSM) approach while parsing the document. Furthermore, the queries that have the same FSM representation are grouped and only one finite state machine is created for each group which contributes to the excellent performance of the system as demonstrated in the performance evaluation section.To provide for user friendliness and expressive power, we have developed a graphical user interface that translates the user profiles into XML-QL. XML-QLs querying power and its elaborate CONSTRUCT statement allows the format of the results to be specified. The results to be pushed to the mobile clients are converted to the markup language of the mobile device such as Wireless Markup Language (WML), CHTML or XHTML by the delivery component of the system.

METU Object-Oriented DBMS Kernel

This paper describes the design and implementation of a kernel for an OODBMS, namely the METU Object-Oriented DBMS (MOOD). MOOD is developed on the Exodus Storage Manager (ESM). MOOD kernel provides the optimization and interpretation of SQL statements, dynamic linking of functions, and catalog management. SQL statements are interpreted whereas functions (which have been previously compiled with C++) within SQL statements are dynamically linked and executed. Thus the interpretation of functions are avoided increasing the efficiency of the system. A query optimizer is implemented by using the Volcano Query Optimizer Generator. A graphical user interface, namely MoodView, is developed using Motif. MoodView displays both the schema information and the query results graphically. Additionally it is possible to update the database schema and to traverse the references in query results graphically.

Research in Data Broadcast and Dissemination

The proliferation of the Internet and intranets, the development of wireless and satellite networks, and the availability of asymmetric, high-bandwidth links to the home, have fueled the development of a wide range of new “dissemination-based” applications. These applications involve the timely distribution of data to a large set of consumers, and include stock and sports tickers, traffic information systems, electronic personalized newspapers, and entertainment delivery. Dissemination-oriented applications have special characteristics that render traditional client-server data management approaches ineffective. These include: tremendous scale. a high-degree of overlap in user data needs. asymmetric data flow from sources to consumers.

Data Mashups for Situational Applications

Situational applications require business users to create combine, and catalog data feeds and other enterprise data sources. Damia is a lightweight enterprise data integration engine inspired by the Web 2.0 mashup phenomenon. It consists of (1) a browser-based user-interface that allows for the specification of data mashups as data flow graphs using a set of Damia operators specified by programming-by-example principles, (2) a server with an execution engine, as well as (3) APIs for searching, debugging, executing and managing mashups. Damia provides a base data model and primitive operators based on the XQuery Infoset. A feed abstraction built on that model enables combining, filtering and transforming data feeds. This paper presents an overview of the Damia system as well as a research vision for data-intensive situational applications. A first version of Damia realizing some of the concepts described in this paper is available as a webserivce [17] and for download as part of IBM’s Mashup Starter Kit [18].

Reweaving the tapestry: integrating database and messaging systems in the wake of new middleware technologies

Modern business applications involve a lot of distributed data processing and inter-site communication, for which they rely on middleware products. These products provide the data access and communication framework for the business applications. Integrated messaging seeks to integrate messaging operations into the database, so as to provide a single API for data processing and messaging. Client applications will be much easier to write, because all the logic of sending and receiving messages is within the database. System configuration, application deployment, and message warehousing are simplified, because we don’t have to manage and fine-tune multiple products. Integrating messaging into a database also provides features like backup, restore, transactionality & recoverability to messages. In this paper, we’ll look at some aspects of messaging systems, and the challenges involved in integrating messaging such as message delivery semantics, transaction management and impact on query processing.