基于遗传算法的NoC路径分配算法

在片上网络中实现通信流明确的应用,通常在编译过程中静态分配路径资源,并把路径分配算法嵌入到映射算法中综合考虑.针对现有基于遗传算法的片上网络路径分配算法,引入了一种完整路径均匀交叉算子,来改善现有算法中路径交叉不充分的问题.实验结果显示:使用新算子的路径分配算法优化了现有算法的结果,减少了计算时间.     

Numerical simulation of complex flow and heat transfer induced by localized laser heating on a urethane-coated substrate

A three-dimensional numerical simulation is conducted for complex flow and heat transfer that incorporate solid–liquid–vapor phase change and surface chemical reaction induced by localized laser heating on a urethane-coated stainless-steel substrate. The surface chemical reaction due to laser irradiation on the urethane-coated stainless-steel substrate, and heat and mass transfer due to melting/vaporization of the stainless steel are considered. The entire problem is solved within one computational domain that includes two solid regions and one gaseous region through a penalty method. One of the solid region is the paint that will decompose via chemical reaction to generate gaseous products and then mix with the air, and the other one is the stainless steel that melting and vaporization can occur due to extremely high temperature in the process. Moreover, the gas phase is considered as a multicomponent system that consists of O₂, N₂, CO₂, H₂O, NO₂, binder vapor, and stainless-steel vapor. In the present multiphysics simulation, the process of melting, vaporization and chemical reaction and the splash of the melted paint and stainless steel into the gas is observed.     

Automated detection of exudates in colored retinal images for diagnosis of diabetic retinopathy

Medical image analysis is a very popular research area these days in which digital images are analyzed for the diagnosis and screening of different medical problems. Diabetic retinopathy (DR) is an eye disease caused by the increase of insulin in blood and may cause blindness. An automated system for early detection of DR can save a patient's vision and can also help the ophthalmologists in screening of DR. The background or nonproliferative DR contains four types of lesions, i.e., microaneurysms, hemorrhages, hard exudates, and soft exudates. This paper presents a method for detection and classification of exudates in colored retinal images. We present a novel technique that uses filter banks to extract the candidate regions for possible exudates. It eliminates the spurious exudate regions by removing the optic disc region. Then it applies a Bayesian classifier as a combination of Gaussian functions to detect exudate and nonexudate regions. The proposed system is evaluated and tested on publicly available retinal image databases using performance parameters such as sensitivity, specificity, and accuracy. We further compare our system with already proposed and published methods to show the validity of the proposed system.     

Addition of the Lewis Acid Zn(C6F5)2 Enables Organic Transistors with a Maximum Hole Mobility in Excess of 20 cm2 V−1 s−1

Incorporating the molecular organic Lewis acid tris(pentafluorophenyl)borane [B(C₆F₅)₃] into organic semiconductors has shown remarkable promise in recent years for controlling the operating characteristics and performance of various opto/electronic devices, including, light‐emitting diodes, solar cells, and organic thin‐film transistors (OTFTs). Despite the demonstrated potential, however, to date most of the work has been limited to B(C₆F₅)₃ with the latter serving as the prototypical air‐stable molecular Lewis acid system. Herein, the use of bis(pentafluorophenyl)zinc [Zn(C₆F₅)₂] is reported as an alternative Lewis acid additive in high‐hole‐mobility OTFTs based on small‐molecule:polymer blends comprising 2,7‐dioctyl[1]benzothieno [3,2‐b][1]benzothiophene and indacenodithiophene–benzothiadiazole. Systematic analysis of the materials and device characteristics supports the hypothesis that Zn(C₆F₅)₂ acts simultaneously as a p‐dopant and a microstructure modifier. It is proposed that it is the combination of these synergistic effects that leads to OTFTs with a maximum hole mobility value of 21.5 cm² V^?1 s^?1. The work not only highlights Zn(C₆F₅)₂ as a promising new additive for next‐generation optoelectronic devices, but also opens up new avenues in the search for high‐mobility organic semiconductors.     

Efficient Algorithms for Cache-Throughput Analysis in Cellular-D2D 5G Networks

In this paper, we propose a two-tiered segment-based Device-to-Device (S-D2D) caching approach to decrease the startup and playback delay experienced by Video-on-Demand (VoD) users in a cellular network. In the S-D2D caching approach cache space of each mobile device is divided into two cache-blocks. The first cache-block reserve for caching and delivering the beginning portion of the most popular video files and the second cache-block caches the latter portion of the requested video files ‘fully or partially’ depending on the users’ video watching behaviour and popularity of videos. In this approach before caching, video is divided and grouped in a sequence of fixed-sized fragments called segments. To control the admission to both cache-blocks and improve the system throughput, we further propose and evaluate three cache admission control algorithms. We also propose a video segment access protocol to elaborate on how to cache and share the video segments in a segmentation based D2D caching architecture. We formulate an optimisation problem and find the optimal cache probability and beginning-segment size that maximise the cache-throughput probability of beginning-segments. To solve the non-convex cache-throughout maximisation problem, we derive an iterative algorithm, where the optimal solution is derived in each step. We used extensive simulations to evaluate the performance of our proposed S-D2D caching system.     

The pseudorandom sequence of arrays

Pseudorandom (or maximal length) sequences and arrays have been known for a long time, and have been reported by several authors. Pseudorandom volumes have also been mentioned.This paper presents a different type of sequence of arrays in which the arrays share many properties with the pseudorandom arrays of the literature, and the sequence (or group) of arrays has many properties in common with the pseudorandom sequences. It is proposed that this set of arrays be called a pseudorandom sequence of arrays, or PRSAs. Some interesting properties of the PRSA as well as its practical (hardware) implementation have been mentioned. It has also been shown that our result is a special case of the generalN(3)/D(3) case.     

Airflow analysis in an air conditioning room

The aim of superior air conditioning system is no longer constrained to advancing the efficiency of cooling machine, but includes the study of airflow with the assistance of the distribution of several significant parameters. A simple numerical study of the turbulent flow over an enclosed air conditioning system was not practicable a few decades ago since the computer facilities were not sufficient. In this paper, a standard office room was taken up for simulation. Temperature and velocity distribution over various virtual planes for different locations of the air conditioner blower were analyzed to achieve the maximum comfort for the occupant. With Fluent, as solution tool, k–epsilon and Reynolds stress models for turbulence flow were used for the analysis. The different locations of blower placement are analyzed for better comfort of occupant in the room and it is found that the occupant will experience most comfort if the air conditioner blower is placed on location II compared to the other two locations. This work can also be extended to a more complex air conditioning system like in the industries, hospitals as well as the gigantic shopping malls.     

Hierarchical congregated ant system for bottom-up VLSI placements

A new perturbation method, called Hierarchical-Congregated Ant System (H-CAS) has been proposed to perform the variable-order bottom-up placement for VLSI. H-CAS exploits the concept of ant colonies, where each ant will generate the perturbation based on differences in dimensions of the VLSI modules in hard modules floorplanning and differences in area of the VLSI modules in soft modules floorplanning. In this paper, it is mathematically proved that the area-based two-dimensional cost function for hard modules floorplanning problem can be reduced to the difference-based one dimensional cost function which avoids local optima problems. Lack of global view is a major drawback in the conventional bottom-up hierarchy, and hence, ants in the H-CAS are made to introduce global information at every level of bottom-up hierarchy. A new relative whitespace formula for bottom-up hierarchy is derived mathematically and the H-CAS embeds it in its unique update formula. The ants in H-CAS are able to communicate among themselves and update the pheromone trails when they reach the destination. Then, the ants will congregate, share their experiences and construct a new pheromone trails that belong to this newly constructed group. The congregation of at least two ants and/or ant consortiums would lead to reduction in subsequent search space and complexity. H-CAS gives the best-so-far near optimal solutions and yields low standard deviations of areas involving 9–600 blocks based on Microelectronics Center of North Carolina (MCNC) and Giga scale Systems Research Center (GSRC) benchmarks. The results obtained establish that H-CAS is a high performance placer in respect of scaling, convergence, precision, stability, and reliability. The above claims are based on the comparisons with the other floorplanning algorithms as depicted graphically.