The complex process of adapting pre-packaged applications, such as Oracle or SAP, to an organization's needs is full of challenges. Although detailed, structured, and well-documented methods govern this process, the consulting team implementing the method must spend a huge amount of manual effort to make sure the guidelines of the method are followed as intended by the method author. MATCON breaks down the method content, documents, templates, and work products into reusable objects, and enables them to be cataloged and indexed so these objects can be easily found and reused on subsequent projects. By using models and meta-modeling the reusable methods, we automatically produce a CASE tool to apply these methods, thereby guiding consultants through this complex process. The resulting tool helps consultants create the method deliverables for the initial phases of large customization projects. Our MATCON output, referred to as Consultant Assistant, has shown significant savings in training costs, a 20 - 30% improvement in productivity, and positive results in large Oracle and SAP implementations.

Business performance modeling and model-driven business transformation are two research directions that are attracting much attention lately. In this study, we propose an approach for dashboard development that is model-driven and can be integrated with the business performance models. We adopt the business performance modeling framework, and we extend it in order to capture the reporting aspect of the business operation. We describe models that can effectively represent all the elements necessary for the business performance reporting process, and the interactions among them. We also demonstrate how all these models can be combined and automatically generate the final solution. Finally, we discuss our experience from the application of our technique in a real-world scenario. This case study shows that our technique can be efficiently applied to and handle changes in the underlying business models, delivering significant benefits in terms of both development time and flexibility

In this paper, we solve the classic problem of computing the average number of decomposed quadtree blocks (quadrants, nodes, or pieces) in quadtree decomposition for an arbitrary hyperrectangle aligned with the axes. We derive a closed-form formula for general cases. The previously known state-of-the-art solution provided a closed-form solution for special cases and utilized these formulas to derive linearly interpolated formulas for general cases individually. However, there is no exact and uniform closed-form formula that fits all cases. Contrary to the top-down counting approach used by most prior solutions, we employ a bottom-up enumeration approach to transform the problem into one that involves the Cartesian product of d multisets of successive 2's powers. Classic combinatorial enumeration techniques are applied to obtain an exact and uniform closed-form formula. The result is of theoretical interest since it is the first exact closed-form formula for arbitrary cases. Practically, it is nice to have a uniform formula for estimating the average number since a simple program can be conveniently constructed taking side lengths as inputs.

Efficient processing of continual range queries over moving objects is critically important in providing location-aware services and applications. A set of continual range queries, each defining the geographical region of interest, can be periodically (re)evaluated to locate moving objects that are currently within individual query boundaries. We study a new query indexing method, called CES-based indexing, for incremental processing of continual range queries over moving objects. A set of containment-encoded squares (CES) are predefined, each with a unique ID. CESs are virtual constructs (VC) used to decompose query regions and to store indirectly precomputed search results. Compared with a prior VC-based approach, the number of VCs visited in a search operation is reduced from (4L2-1)/3 to log(L)+1, where L is the maximal side length of a VC. Search time is hence significantly lowered. Moreover, containment encoding among the CESs makes it easy to identify all those VCs that need not be visited during an incremental query (re)evaluation. We study the performance of CES-based indexing and compare it with a prior VC-based approach

A set of continual range queries, each defining the geographical region of interest, can be periodically re-evaluated to locate moving objects. Processing these continual queries efficiently and incrementally hence becomes important for location-aware services and applications. In this paper, we study a new query indexing method, called CES-based indexing, for incremental processing of continual range queries over moving objects. A set of containment-encoded squares (CES) are predefined, each with a unique ID. CES's are virtual constructs (VC) used to decompose query regions and to store indirectly pre-computed search results. Compared with a prior VC-based approach, the number of VC's visited in an index search in CES-based indexing is reduced from (4L/sup 2/-1)/3 to log(L)+1, where L is the maximal side length of a VC. Search time is hence significantly lowered. Moreover, containment encoding among the CES's makes it easy to identify all those VC's that need not be visited during an incremental query reevaluation. We study the performance of CES-based indexing and compare it with a prior VC-based approach.

A large number of continual range queries can be issued against a data stream. Usually, a main memory-based query index with a small storage cost and a fast search time is needed, especially if the stream is rapid. In this paper, we present a CEI-based query index that meets both criteria for efficient processing of continual interval queries in a streaming environment. This new query index is centered around a set of predefined virtual containment-encoded intervals, or CEIs. The CEIs are used to first decompose query intervals and then perform efficient search operations. The CEIs are defined and labeled such that containment relationships among them are encoded in their IDs. The containment encoding makes decomposition and search operations efficient because integer additions and logical shifts can be used to carry out most of the operations. Simulations are conducted to evaluate the effectiveness of the CEI-based query index and to compare it with alternative approaches. The results show that the CEI-based query index significantly outperforms existing approaches in terms of both storage cost and search time.

This paper describes VCR-based query indexes for efficient processing of continual range queries over moving objects. A set of virtual construct rectangles (VCR) is predefined, each with a unique ID. One or more VCRs is used to strictly cover the entire region defined by a range query. The query index maintains a mapping from each VCR to the range queries that contain that VCR. The use of VCRs provides an indirect and cost-effective way of precomputing the search result for any object position, making possible efficient search operations. More importantly, it allows the processing of continual range queries to capitalize on incremental changes in object locations. Computation can be saved for objects that have not moved out of VCR boundaries. We study different strategies to cover a query region with VCRs and conduct simulations to compare them.

XML is emerging as an important format for describing the schema of documents and data to facilitate integration of applications in a variety of industry domains. An important issue that naturally arises is the requirement to generate, store and access XML documents. It is important to reuse existing data management systems and repositories for this purpose. We describe the XML Access Server (XAS), a general purpose XML based storage and retrieval system which provides the appearance of a large set of XML documents while retaining the data in underlying federated data sources that could be relational, object-oriented, or semi-structured. XAS automatically maps the underlying data into virtual XML components when mappings between DTDs and underlying schemas are established. The components can be presented as XML documents or assembled into larger components. XAS manages the relationship between XML components and the mapping in the form of document composition logic. The versatility in its ways to generate XML documents enables XAS to serve a large number of XML components and documents efficiently and expediently.

Very Long Instruction Word (VLIW) architectures can enhance performance by exploiting fine-grained instruction level parallelism. In this paper, we describe a compiler assisted multiple instruction word retry scheme for VLIW architectures. A read buffer is used to resolve the more frequent on-path hazards, while the compiler resolves the remaining branch hazards. Performance evaluation is described for 11 benchmark programs based on the IBM VLIW research compiler, Chameleon. Experimental results indicate that, for a VLIW machine with P functional units to rollback N instruction words, a read buffer of 2NP entries with the compiler assist can be an effective approach in producing low overhead runtime performance and small code growth, for P = 4, 8, 12, and 16 and N /spl les/ 3.

Reversible execution has not been fully exploited in symbolic debuggers. Debuggers that can undo instructions usually incur a significant performance penalty during a debugging session. We describe an efficient reversible debugging mechanism based on program instrumentation. The approach enables repetitive debugging sessions with selectable reversible routines and recording modes. Experimental results indicate that the execution penalty can be significantly reduced with moderate code growth.

Multiple instruction rollback (MIR) is a technique that has been implemented in mainframe computers to provide rapid recovery from transient processor failures. Hardware-based MIR designs eliminate rollback data hazards by providing data redundancy implemented in hardware. Compiler-based MIR designs have also been developed which remove rollback data hazards directly with data-flow transformations. This paper describes compiler-assisted techniques to achieve multiple instruction rollback recovery. We observe that some data hazards resulting from instruction rollback can be resolved efficiently by providing an operand read buffer while others are resolved more efficiently with compiler transformations. The compiler-assisted scheme presented consists of hardware that is less complex than shadow files, history files, history buffers, or delayed write buffers, while experimental evaluation indicates performance improvement over compiler-based schemes.>

This paper describes a compiler-based approach to provide multiple instruction rollback capability for general purpose processor registers. The objective is achieved by having the compiler remove all forms of N-instruction antidependencies. Pseudoregister antidependencies are removed by loop protection, node splitting, and loop expansion techniques; machine register antidependencies are prevented by introducing antidependency constraints in the interference graph used by the register allocator. To support separate compilation, inter-procedural antidependency constraints are added to the code generator to guarantee the termination of machine register antidependencies across procedure boundaries. The algorithms have been implemented in the IMPACT C compiler. Experiments illustrating the effectiveness of this approach are described.>

Superscalar and Very Long Instruction Word (VLIW) architectures exploit fine-grain parallelism to achieve better performance. Static scheduling techniques, such as trace scheduling and superblock scheduling, can effectively produce compact code for these architectures. In this paper, we present an analytical approach for bookkeeping in code scheduling that alleviates the coding complexity and instruction duplication limitations of the previous approaches. We describe techniques that allow instructions to be moved around loop and if-then-else constructs using global information. We also show that according to the classification of the register sets, certain instructions can be moved around subroutine calls, since their register live ranges can be predetermined across the procedural boundaries at compile time. Performance is compared with respect to the speed-up, the code size and the scheduling time. Experimental results indicate that the code growth and the speed-up are both improved with a small increase in scheduling time.

Abstract Previous work on compiler‐based multiple instruction retry has utilized a series of compiler transformations, loop protection, node splitting, and loop expansion, to eliminate anti‐dependencies of length ≤Nin the pseudo register, the machine register, and the post‐pass resolver phases of compilation.1The results have provided a means of rapidly recovering from transient processor failures by rolling backNinstructions. This paper presents techniques for improving compilation and run‐time performance in compiler‐based multiple instruction retry. Incremental updating enhances compilation time when new instructions are added to the program. Post‐pass code rescheduling and spill register reassignment algorithms improve the run‐time performance and decrease the code growth across the application programs studied. Branch hazards are shown to be resolvable by simple modifications to the incremental updating schemes during the pseudo register phase and to the spill register reassignment algorithm during the post‐pass phase.

An analysis is conducted of the complexity of placing recovery points where the computation is modeled as a reverse binary tree task model. The objective is to minimize the expected computation time of a program in the presence of faults. The method can be extended to an arbitrary reverse tree model. For uniprocessor systems, an optimal placement algorithm is proposed. For multiprocessor systems, a procedure for computing their performance is described. Since no closed form solution is available, an alternative measurement is proposed that has a closed form formula. On the basis of this formula, algorithms are devised for solving the recovery point placement problem. The estimated formula can be extended to include communication delays where the algorithm devised still applies.>