17211338
Memory Architecture Exploration for Power-Efficient 2D-Discrete Wavelet Transform
The discrete wavelet transform (DWT) forms the core of the JPEG2000 image compression algorithm. Since the JPEG2000 compression application is heavily data-intensive, the overall power dissipation is dominated by read and write operations in the memory subsystem. The proposed architecture and computation sequence, called low-power block-scan, takes into account the EBCOT (embedded block coding with optimized truncation) code block size, which reduces the intermediate buffer requirement between the DWT and EBCOT modules. The impact of different memory subsystem optimization techniques on the overall memory power for 2D-DWT computation was modeled. The proposed model explores the different data access patterns, memory bank partitioning, and custom memory architectures to arrive at a power-efficient DWT architecture
16168118
Defect-aware design paradigm for reconfigurable architectures
With advances in process technology, the feature sizes are decreasing, which leads to higher defect densities. More sophisticated techniques, at increased costs are required to avoid defects. If nanotechnology based fabrications are applied, the yield may even go down to zero, as avoiding defects during fabrication will not be a feasible option. Hence, future architectures have to be defect-tolerant. Most of the current defect-tolerance schemes introduce redundancy in architecture to combat defects. Alternatively we can introduce defect tolerance in the design-flow. In this paper we analyze the bottlenecks faced by current design-methodologies while addressing defect tolerance. We study the performance of present place and route tools on a defective fabric in terms of area and critical delay penalty, and explore routing aware placement in this context. We have proposed a new cost function, CA-RISA for improving the performance in a defect-aware environment
15132229
OSU-MAC: a new, real-time medium access control protocol for wireless WANs with asymmetric wireless links
In this paper, we document our design of a MAC protocol, called OSU-MAC, subject to the physical layer characteristics and constraints of a narrow-band wireless modem testbed currently being built at the Ohio State University. The narrow-band wireless modem testbed is expected to support both real-time (bus location tracking) and non-real-time (regular) data applications. A number of techniques are proposed to support QoS imposed by the real-time applications, to deal with the asymmetry on the forward and reverse channels and the half-duplex transmission constraint imposed by the physical layer, and to enhance the error control capability of OSU-MAC. We also present simulation results to demonstrate the key functional characteristics of OSU-MAC.
14965039
ABR Flow Control for Multipoint Connections
Multipoint capabilities are essential for ATM networks to efficiently support many applications, including IP multicasting and overlay applications. The current signaling and routing specifications for ATM define point-to-multipoint capabilities. Multipoint-to-point connection support is also being discussed by the signaling and PNNI groups, and will be defined in the near future for the unspecified bit rate (UBR) service. We examine point-to-multipoint and multipoint-to-point flow control for the available bit rate (ABR) service, as discussed in the traffic management working group.
2278641
Classifying Mushrooms in the Hybridized Rough Sets Framework
5474275
Overload based explicit rate switch schemes with MCR guarantees
An explicit rate switch scheme monitors the load at each link and gives feedback to the sources. We define the overload factor as the ratio of the input rate to the available capacity. In this paper, we present three overload-based switch schemes which provide MCR (minimum cell rate) guarantees for the ATM (asynchronous transfer mode) ABR (available bit rate) service. The switch schemes proposed use the overload factor and other terms including current source rate and target utilization to calculate feedback rates. A dynamic queue control mechanism is used to achieve efficient usage of the link, control queues and, achieve constant queuing delay at steady state. The proposed algorithms are studied and compared using several configurations. The configurations were chosen to test the performance of the algorithms in the presence of link bottlenecks, source bottlenecks and transient sources. Finally, a comparison of the proposed algorithms based on the simulation results is given.
62102705
Performance analysis of FDDI token ring networks: effect of parameters and guidelines for setting TTRT
Fiber-Distributed Data Interface (FDDI) is a 100-Mbps Local Area Network (LAN) standard being developed by the American National Standards Institute (ANSI). It uses a timed-token access method and allows up to 500 stations to be connected with a total fiber length of 200 km. We analyze the performance of FDDI using a simple analytical model and a simulation model. The performance metrics of response time, efficiency, and maximum access delay are considered. The efficiency is defined as the ratio of maximum obtainable throughput to the nominal bandwidth of the network. The access delay is defined as the time it takes to receive a usable token. The performance of FDDI depends upon several workload parameters; for example; the arrival pattern, frame size, and configuration parameters, such as the number of stations on the ring, extent of the ring, and number of stations that are waiting to transmit. In addition, the performance is affected by a parameter called the Target Token Rotation Time (TTRT), which can be controlled by the network manager. We considered the effect of TTRT on various performance metrics for different ring configurations, and concluded that a TTRT value of 8 ms provides a good performance over a wide range of configurations and workloads.