17585976
Evaluation of various routing architectures for multi-FPGA boards
Multi-FPGA boards are being used for logic emulation, rapid prototyping, custom computing and low volume subsystem implementation. A key feature which characterizes these boards is their routing architecture (RA). Inter-FPGA connections in an RA can be of two types, named, fired connections through direct wires and programmable connections through intermediate Field-Programmable Interconnect Devices. This paper presents an analytical approach for evaluating routing performance of an RA employing both types of connections. Our approach consists of two steps: 1) generation of a random interconnection requirement matrix for modeling real circuits with an orientation towards the available interconnection architecture. 2) Checking the routability of the generated matrix on the given RA. The evaluation experiments for many RAs demonstrate that our methodology matches in results with purely experiment based approaches. However, it is more versatile in that it can evaluate new RAs. Also it provides more observability and controllability of architectural, circuit and performance parameters.
2205933
Hybrid Multi-FPGA board evaluation by limiting multi-hop routing
Multi-FPGA Boards (MFBs) have been in use for more than a decade for emulation of the digital circuits in many applications. Key feature of an MFB architecture is its inter-FPGA connections. There are two types of inter-FPGA connections namely: i) fixed connection (FC)-connecting a pair of FPGAs through a dedicated wire between them, ii) programmable connection (PC)-connecting a pair of FPGAs through a programmable switch like Field-Programmable Interconnect Device (FPID). Hence, a PC requires two wires compared to one wire in FC. Khalid et al. (1999) have shown that the MFBs consisting of both the types of connections (hybrid MFBs) are better than other architectures for emulation of the circuits, if the number of PCs are minimum required. Hence, we evaluate the hybrid MFBs for the required number of PCs as an evaluation metric. Availability of technology mapping, partitioning, embedding and routing tools is another important requirement for emulation. A routing tool (multi-hop router) prefers one or more unused FCs (multi-hops) in lieu of one PC. Available multihop routers are specific to MFB architecture and use unlimited hops in the routes. For evaluation, a generic multi-hop router for any hybrid architecture is required which obeys the given limit on maximum number of hops in every route. This paper presents the development of routing tool for the same. A heuristic, a lower bound and an optimal algorithm has been implemented for this purpose. For the test cases, it has been observed that the optimal results (within 3 hours) are achievable by the heuristic (within a minute). Also the results are more precise than the available results.
6148667
Supply chain management tradeoffs analysis
Supply chain management involves understanding complex interactions between many factors and using the understanding to achieve balance between conflicting objectives. Simulation is a very useful technique to evaluate the impact of changes in factors such as inventory control and business process parameters. This paper describes a simulation based study for analyzing the tradeoffs among service level, inventory and lead times for a large logistics supply chain. The study highlights the use of simulation in understanding seemingly non-intuitive results and guiding the effort for performance improvement.
7115385
Integrated simulation and gaming architecture for incident management training
The simulation-based training systems that are available or under development today for incident management are typically focused on macro level sequence of events. A few systems targeted at individual responders are under development using a gaming environment. Separate uses of such systems provide disparate experiences to decision makers and individual responders. There is a need to provide common training experiences to these groups for better effectiveness. This paper presents a novel approach integrating gaming and simulation systems for training of decision makers and responders on the same scenarios preparing them to work together as a team. An integrated systems architecture is proposed for this purpose. Major modules in gaming and simulation subsystems are defined and interaction mechanisms established. Research and standards issues for implementation of the proposed architecture are discussed.
6477912
Stress testing a supply chain using simulation
Simulation provides the capability to evaluate performance of a system operating under current or proposed configurations, policies and procedures. It is very applicable to evaluation of strategic and operational level plans for supply chains. It is especially useful for exploring the viability of a supply chain before beginning production. This paper describes the use of simulation for determining the readiness of a supply chain designed by a small company for providing sub-systems to a defense contractor. The supply chain had to be stress tested at surge and mobilization volume levels to meet the requirements. Simulation provided the ideal methodology to identify and demonstrate the behavior of the supply chain under stress and evaluate strategies to meet the defined volumes. It was used to prove the readiness of the supply chain reducing perceived risks in using the virtual operation.
206721
An approximation to the greedy algorithm for differential compression of very large files
This paper presents a new differential compression algorithm that combines the hash value and suffix array technique. In this algorithm, hash values for every block of the reference file is computed. Next, suffix arrays on these block hash values are computed. This algorithm finds the longest matches for every offset of the version file. This algorithm depends upon the utilization of three new data structures, the block hash table, the quick index array, and the pointer array, which improves the run-time of the algorithm, and compress very large files.
5872084
Experiences with backward simulation based approach for lot release planning
Bottleneck based scheduling approach suggests planning the release of lots based on the capacity of the bottleneck machines in the manufacturing process. Many scheduling systems determine the start of the first operation of the lot based on backward scheduling from its operation on the bottleneck machine. An approach was developed for determining the lot release times based on backward simulation. While conceptually appealing and successful with simple problems, the approach did not lead to expected improvements in a highly complex semiconductor manufacturing scenario. This paper describes the approach, its implementation and the limitations realized in the complex scenario.