A priori wire length distribution models with multiterminal nets

Author(s):  
D. Stroobandt
2004 ◽  
Vol 12 (10) ◽  
pp. 1108-1112 ◽  
Author(s):  
M.Y. Lanzerotti ◽  
G. Fiorenza ◽  
R.A. Rand

1997 ◽  
Vol 473 ◽  
Author(s):  
J. A. Davis ◽  
J. D. Meindl

ABSTRACTOpportunities for Gigascale Integration (GSI) are governed by a hierarchy of physical limits. The levels of this hierarchy have been codified as: 1) fundamental, 2) material, 3) device, 4) circuit and 5) system. Many key limits at all levels of the hierarchy can be displayed in the power, P, versus delay, td, plane and the reciprocal length squared, L-2, versus response time, τ, plane. Power, P, is the average power transfer during a binary switching transition and delay, td, is the time required for the transition. Length, L, is the distance traversed by an interconnect that joins two nodes on a chip and response time, τ, characterizes the corresponding interconnect circuit. At the system level of the hierarchy, quantitative definition of both the P versus td and the L-2 versus τ displays requires an estimate of the complete stochastic wiring distribution of a chip.Based on Rent's Rule, a well known empirical relationship between the number of signal input/output terminals on a block of logic and the number of gate circuits with the block, a rigorous derivation of a new complete stochastic wire length distribution for an on-chip random logic network is described. This distribution is compared to actual data for modern microprocessors and to previously described distributions. A methodology for estimating the complete wire length distribution for future GSI products is proposed. The new distribution is then used to enhance the critical path model that determines the maximum clock frequency of a chip; to derive a preliminary power dissipation model for a random logic network; and, to define an optimal architecture of a multilevel interconnect network that minimizes overall chip size. In essence, a new complete stochastic wiring distribution provides a generic basis for maximizing the value obtained from a multilevel interconnect technology.


2021 ◽  
Vol 4 ◽  
Author(s):  
Micaela Hellstrom ◽  
Kat Bruce ◽  
Rein Brys ◽  
Bernd Hänfling ◽  
David Halfmaerten ◽  
...  

Sound environmental management decisions - in accordance with the EU WFD for aquatic ecosystems – mainly depend on reliable species presence- and distribution- data. Here we present a workflow from sampling strategies to results and decision making using eDNA metabarcoding analyses for fish, amphibians, and mussels from habitat to landscape scales with focus on sampling strategies for "big data" in marine and freshwater ecosystems in Sweden. The project LifeDNAquatic highlights a solid eDNA pipeline and comparison of methods, which cover field planning and the entire pipeline generating data for Species Distribution Models (SDMs). Intense sampling over a large river catchment highlights previoulsy unanswered questionsand and provides insights to a priori settings for sampling strategies to retrieve "big data". The results provide novel insights to DNA distribution in the environment, seasonal and spatial changes in eDNA composition, and validation of data.


VLSI Design ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-14
Author(s):  
L. Rakai ◽  
A. Farshidi ◽  
L. Behjat ◽  
D. Westwick

Clustering algorithms have been used to improve the speed and quality of placement. Traditionally, clustering focuses on the local connections between cells. In this paper, a new clustering algorithm that is based on the estimated lengths of circuit interconnects and the connectivity is proposed. In the proposed algorithm, first an a priori length estimation technique is used to estimate the lengths of nets. Then, the estimated lengths are used in a clustering framework to modify a clustering technique based on algebraic multigrid (AMG), that finds the cells with the highest connectivity. Finally, based on the results from the AMG-based process, clusters are made. In addition, a new physical unclustering technique is proposed. The results show a significant improvement, reductions of up to 40%, in wire length can be achieved when using the proposed technique with three academic placers on industry-based circuits. Moreover, the runtime is not significantly degraded and can even be improved.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247985 ◽  
Author(s):  
Steven B. Garner ◽  
Aaron M. Olsen ◽  
Ryan Caillouet ◽  
Matthew D. Campbell ◽  
William F. Patterson

We tested the efficacy of a stereo camera (SC) system adapted for use with a remotely operated vehicle (ROV) to estimate fish length distributions at reef sites in the northern Gulf of Mexico. A pool experiment was conducted to test the effect of distance (1, 2, 3 or 5 m), angle of incidence (AOI; 0° to 40° at 5° increments), and SC baseline distance (BD; BD1 = 406, BD2 = 610, and BD3 = 762 mm camera separation) on the accuracy and precision of fish model length (288, 552, or 890 mm fork length) estimates compared to a red laser scaler (RLS). A field experiment was then conducted at 20 reef sites with SCs positioned at BD1 to compare fish length distribution estimates between the SC and RLS systems under in situ conditions. In the pool experiment, mean percent errors were consistently within the a priori selected threshold of ±5% at AOIs ≤10° at all distances with all four systems. However, SCs produced accurate estimates at AOIs up to 30° at all distances tested; 2–3 m was optimal. During reef site surveys, SCs collected 10.4 times as many length estimates from 4.3 times as many species compared to the RLS. Study results demonstrate that, compared to laser scalers, ROV-based SC systems can substantially increase the number of available fish length estimates by producing accurate length estimates at a wider range of target orientations while also enabling measurements from a greater portion of the cameras’ field of view.


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