Three-layer router for channels with constrained terminals

A new channel routing model, which allows horizontal and vertical wire segments to be placed on both layers and two wires on different layers to be overlapped, is presented. Based on this model, the basic constraints as well as the rules of layer assignment and routing order in two-layer channel routing are obtained. Then the property of optimal overlapping in a zone is analyzed. For the example used, this algorithm obtains 18 tracks solution.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The authors present a new three-layer over-the-cell channel routing algorithm, WILMA3 (wire length minimization algorithm 3), for high-performance circuits. This router not only minimizes the channel height by OTC routing but also minimizes the net lengths. They have also developed a two-layer router, WILMA2. Both WILMA2 and WILMA3 achieve reduction in channel height while maintaining the net length greater than its length in the two-layer channel routing. Experimental results with WILMA2 indicated that WILMA2 can produce routings that are comparable to existing two-layer over-the-cell routers. Both WILMA2 and WILMA3 achieved these results, while maintaining the net length bound. >

Wireless mesh networks are being deployed all around the world both to provide ubiquitous connection to the Internet and to carry data generated by several services (video surveillance, smart grids, earthquake early warning systems, etc.). In those cases where fixed power connections are not available, mesh nodes operate by harvesting ambient energy (e.g., solar or wind power) and hence they can count on a limited and time-varying amount of power to accomplish their functions. Since we consider mesh nodes equipped with multiple radios, power savings and network performance can be maximized by properly routing flows, assigning channels to radios and identifying nodes/radios that can be turned off . Thus, the problem we address is a joint channel assignment and routing problem with additional constraints on the node power consumption, which is NP-complete. In this paper, we propose a heuristic, named minimum power channel assignment and routing algorithm (MP-CARA), which is guaranteed to return a local optimum for this problem. Based on a theoretical analysis that we present in the paper, which gives an upper bound on the outage probability as a function of the constraint on power consumption, we can guarantee that the probability that a node runs out of power with MP-CARA falls below a desired threshold. The performance of MP-CARA is assessed by means of an extensive simulation study aiming to compare the solutions returned by MP-CARA to those found by other heuristics proposed in the literature.

A new algorithm for channel routing is presented which addresses the special problems of bit-slice architectural assembly, namely the broadcasting and cascading of signals through layout slices. This is achieved by end-on abutment of channels. The method, used in the bit-slice assembler Slicesyn, is based on a heuristic approach using graph theory.

As technology advances, interconnection wires are placed in closer proximity and circuits operate at higher frequencies. Consequently, reduction of crosstalk between interconnection wires becomes an important consideration in VLSI design. In this paper, we study the gridded channel routing problem with tbe objective of satisfying crosstalk constraints for the nets. We proposed a new approach to the problem which utilizes existing channel routing algorithms and improves upon the routing results by permuting the routing tracks. The permutation problem is proven to be NP-complete. A novel mixed ILP formulation and effective procedures for reducing the number of variables and constraints in the mixed ILP formulation are then presented. The new algorithm is tested on three large benchmark circuits as well as many randomly generated circuits. The experimental results are very promising.

An efficient merger of the channel routing theory and the genetic stochastic search introduces a new paradigm for VLSI channel routing. The feasibility of the paradigm is demonstrated by the first genetic router for Manhattan model channels which contain cyclic vertical constraints. The router has been implemented as a self contained genetic algorithm system. It creates an initial population without violations of constraints using the results of a new theory of locally optimal breaking of cyclic vertical constraints. The population size is problem instance dependent to provide for the preservation of the structural diversity which is built into the initial population. A new encoding scheme and novel crossover and mutation operators are introduced. Convergence rates to optimal solutions are excellent.

An important part of the integrated circuit design process is the channel routing stage, which determines how to interconnect components that are arranged in sets of rows. The channel routing problem has been shown to be NP-complete, thus this problem is often solved using genetic algorithms. The traditional objective for most channel routers is to minimize total area required to complete routing. However, another important objective is to minimize signal propagation delays in the circuit. This paper describes the development of a genetic channel routing algorithm that uses a Pareto-optimal approach to accommodate both objectives. When compared to the traditional channel routing approach, the new channel router produced layouts with decreased signal delay, while still minimizing routing area.

Spectrum-aware cross-layered routing protocol for cognitive radio ad hoc networks

Sequence–function relationship in a protein is commonly determined by the three-dimensional protein structure followed by various biochemical experiments. However, with the explosive increase in the number of genome sequences, facilitated by recent advances in sequencing technology, the gap between protein sequences available and three-dimensional structures is rapidly widening. A recently developed method termed deep mutational scanning explores the functional phenotype of thousands of mutants via massive sequencing. Coupled with a highly efficient screening system, this approach assesses the phenotypic changes made by the substitution of each amino acid sequence that constitutes a protein. Such an informational resource provides the functional role of each amino acid sequence, thereby providing sufficient rationale for selecting target residues for protein engineering. Here, we discuss the current applications of deep mutational scanning and consider experimental design.

In this paper we have developed algorithms for generating random channel instances for their use in computing channel routing solutions in VLSI physical design. Channel instances are usually of two types: simple and general, and there are usually two kinds of inherent constraints involving channel routing problem: horizontal constraint and vertical constraint. Simple channel instances do not contain any vertical constraint, whereas, general channel instances contain both horizontal as well as vertical constraints. Most of the optimization problems in two-, three-, and multi-layer channel routing are NP-hard and, in fact, very few are polynomial time computable. Hence for each of the NP-hard problems in channel routing, it is unlikely to design a polynomial time deterministic algorithm. Developing heuristic algorithm may be a probable way out that hopefully provides good solutions for most of the instances available in literature. Novelty of a heuristic algorithm is judged better if it works for a variety of large number of randomly generated instances of the problem.

In this paper, visualization techniques are applied to the implementation and analysis of a known channel routing algorithm. The main features of the algorithm are visualized in order to make easier the user's approach to it.

Adiabatic quantum-flux-parametron (AQFP) logic is a very energy-efficient superconductor logic due to zero static power dissipation and adiabatic switching operation. However, there is a shortage of electronic design automation (EDA) software tools adaptable to AQFP logic. Such tools are essential for designing large-scale-integration circuits efficiently. Therefore, we have developed a first set of EDA tools that handle cell placement and wiring, written in SKILL, the Cadence scripting language. Our tools also consider the maximum wire length constraint that exists in AQFP logic. First, AQFP logic cells are repositioned via the genetic algorithm to minimize the number of wires that violate the wiring length constraint. Buffers are then automatically inserted as signal repeaters for logic rows where the violations still exist. We then complete the logic wiring of the circuit using the channel routing algorithm. We demonstrate the usability of the EDA tools by designing a 16-bit adder as well as a randomly generated test circuit.

The goal of a channel routing algorithm is to route the nets with as few tracks as possible to minimize the chip area and achieve 100 percent connection. However, the manufacturing yield may not reach a satisfactory level if care is not taken to reduce the critical areas which are susceptible to defects. A new channel routing algorithm is presented to deal with this problem. The approach is to systematically eliminate critical areas by floating, burying, and bumping net segments as well as shifting vias. The yield optimizing routing (YOR) algorithm also minimizes the number of vias. The experimental results show that large reduction in the number of critical areas and significant improvement in yield are achieved. >

Recent advances in VLSI technology have made the area over cells available for routing. In this paper we present a new over-the-cell channel router that uses greedy heuristics to make the over-the-cell connections and to define the nets needed to complete the connections inside the channel. The router tries to reduce the channel density by moving segments that cross maximum density columns to the over-the-cell areas. The layout model used allows only planar connections over each cell. The final stage is to use an existing channel router to route the connections inside the channel. An important characteristic of the new router is that there is interaction between the decisions made for the over-the-cell connections and the connections needed inside the channel. It performs significantly better than previous over the-cell routers.

Chapter 4 - Defining the origin and function of bovine milk proteins through genomics: The biological implications of manipulation and modification