32478144
Experience from a real life query optimizer
DB2 is a major relational database system on IBM main frames, it has over six thousand licenses over the world to support a very large number of major applications for customer business, Optimizer in DB2 is a critical component for the query processing, it inherited system R technologies and has been improved in very many aspects from numerous valuable real life experiences on customer applications. The major DB2 optimizer enhancements will be discussed with the backgrounds and examples. A wish list for future enhancements as well as some trend and direction of DB2 optimizer will also be discussed.
8581173
Recent database challenges in China on data consolidation and integration
During the first phase of IT exploitation in China, a lot of isolated systems were developed and deployed over all the sites where the business took place. Each system typically dealt with one simple local business application. Since the mid 90's, data consolidation and data integration became critical to address the business need for cheaper cost, shorter time to the market as well as better business decision and control. Without consolidated and integrated data, there is no way to support new and complex applications for rapid and large scale business growth in China across lots of industries such as financial, telecom, government, manufacture and distribution.
 When database is used for companies and government agencies in China, the large Chinese population makes the database volume huge. A nation-wide bank or an insurance company has hundreds of millions accounts easily. A province-level telecom service provider has tens of millions subscribers. In certain domains, such as banking and telecom, many applications are executed as on-line transactions which ask for large transaction throughput with good response time. A province-level telecom service provider expects to handle up to 100 billion calls in a month. In this case, most of the phone calls will be pre-paid type and these calls need to be handled in near-real time.
 In order to satisfy the performance requirement, some applications implement application cache on application servers. This approach improves the application performance in getting data but it also introduces the complexity and longer delay when a failure in application occurs. Database management systems can provide client cache for powerful application servers in these days. As more and more application servers are added to respond large number of concurrent users and high volume transaction throughput, database management system must be highly scalable. Both logical and physical contentions should be avoided or greatly reduced. Continuous availability and high reliability are more critical for a consolidated large database because many users and applications rely on it. Both planned outage and unplanned outage should be avoided or minimized through appropriate duplication and redundancy. Smooth transition through cooperative versions of data helps reduce planned outages.
 Swift switch over to hot stand-by database system helps minimize the unplanned outages. Database management systems are expected to be autonomic and remain healthy in resource utilization with minimal administrative involvement. As a summary, data consolidation in China asks for low-cost, high performance database systems with high scalability, availability and reliability on very large database volume.
 Data integration in China often deals with both a horizontal layer of multiple lines of business and a vertical organizational structure. For government agencies, there are at least four levels across nation, province, district and county. There are a few industry specific data models and solutions to address the requirements of data integration. However, a common data integration platform has been constantly requested by many IT projects of large scale. In many cases, business control processes need to integrate business operation processes to support near-real time decision and control. There is a high demand for a practical and well-proven methodology with tool sets which can support data integration life cycle of architect, design, development, deployment and change management.
 Rapid economic and business growth in combination of the join to WTO created big demand in IT evolution across China business, industry and government. There are many demands and opportunities of data consolidation and integration with large data volume and system complexity. The demand of low-cost solutions makes it even more challenging.
20214518
Extensible Indexing Support in DB2 Universal Database
Publisher Summary Emerging database (DB) applications require the scalable management of a large quantity of complex data, together with traditional business data and flexible querying capabilities for business intelligence. Object-relational databases or universal servers are component database management systems (DBMSs) developed to support applications. They leverage the mature relational database technology that provides scalability, reliability, and recovery. They enable users to introduce application-specific types and methods into a database. These extensibility features can be seen as infrastructure for providing plug-in components that extend the built-in repertoire of database types and functions with support for additional, nonstandard data types. Tables in a database may contain user-defined objects such as geographical shapes, images, and semi-structured or unstructured text documents. This chapter presents a high-level framework of indexing for user-defined types. The framework allows users to concentrate on the semantics of applications and user-defined predicates without being concerned with the low-level details of locking, recovery, buffer management, or balanced search-tree updates. It is tightly integrated with the database engine and enhances the value of underlying access methods, built-in or user-defined, in a database system by supporting indexing on new data types and indexed scans using new predicates.
13203624
A distributed object tracing system
Trace-based analysis has always been used to guide and motivate more effective hardware and software design. Existing traces available, however, are unsuitable for studying object-based storage system, a very active area of current storage research, because they are collected from the traditional file systems and don't contain information about object. Thus, a kind of distributed object tracing system is presented in this paper which built on the object-based Lustre file system. The tracing system regards object as capturing unit which we also call it object-trace. Objects information is synchronously captured from three software subsystems of Lustre cluster file system, and eventually integrated into one entire trace for every request of each user. To improve I/O performance and efficiency, we employ a ring of buffers to store trace data which finally is written out to a trace file by an output driver. In particular, we use some database tables to save the final incorporated traces for convenient post-analysis. A prototype of object tracing system is designed and implemented on Linux
60451548
Switching Hypothesized Measurements: A Dynamic Model with Applications to Occlusion Adaptive Joint Tracking
This paper proposes a dynamic model supporting multimodal state space probability distributions and presents the application of the model in dealing with visual occlusions when tracking multiple objects jointly. For a set of hypotheses, multiple measurements are acquired at each time instant. The model switches among a set of hypothesized measurements during the propagation. Two computationally efficient filtering algorithms are derived for online joint tracking. Both the occlusion relationship and state of the objects are recursively estimated from the history of measurement data. The switching hypothesized measurements (SHM) model is generally applicable to describe various dynamic processes with multiple alternative measurement methods.
10165712
A Novel Secure Routing System in Overlay Environment
Routers are effective building blocks for Internet. It is almost impossible to modify router software only for applications. How to satisfy applications’ specific requirements of communication is a big problem. Now more and more systems begin to place application oriented routing service on overlay networks. This paper compares several overlay routing systems based on route number and brings forward a novel routing system based on trust model. System design principles are discussed and system simulation performance is analyzed. The results show that the system is able to provide secure routing service to applications in the case of vicious nodes.
206606945
Self-organization Data Gathering for Wireless Sensor Networks
Sensor networks have attracted much attention in the recent years for its wide applications in biology, medicine, security and battlefield, etc. Data gathering is one of the most important operations in wireless sensor networks. In this paper, we present an energy-delay efficient data gathering protocol, SODG, for sensor networks while taking the transmission interference into considerations. The significance of this proposal is that it is fully localized and distributed, and only depends on the one-hop neighbors’ information. To minimize the delay, the parallel transmissions are permitted with interference- free guaranteed. The experimental simulations show that our protocol is energy- delay efficient. Especially, SODG protocol improves about 64% over PEGASIS on energy consumption, and about 80% over chain-based protocols on delay.