Design Electronic Circuits Using Evolutionary Algorithms

Graph representations promise several desirable properties for genetic programming (GP); multiple-output programs, natural representations of code reuse and, in many cases, an innate mechanism for neutral drift. Each graph GP technique provides a program representation, genetic operators and overarching evolutionary algorithm. This makes it difficult to identify the individual causes of empirical differences, both between these methods and in comparison to traditional GP. In this work, we empirically study the behaviour of Cartesian genetic programming (CGP), linear genetic programming (LGP), evolving graphs by graph programming and traditional GP. By fixing some aspects of the configurations, we study the performance of each graph GP method and GP in combination with three different EAs: generational, steady-state and (1+lambda ). In general, we find that the best choice of representation, genetic operator and evolutionary algorithm depends on the problem domain. Further, we find that graph GP methods can increase search performance on complex real-world regression problems and, particularly in combination with the (1 + lambda) EA, are significantly better on digital circuit synthesis tasks. We further show that the reuse of intermediate results by tuning LGP’s number of registers and CGP’s levels back parameter is of utmost importance and contributes significantly to better convergence of an optimization algorithm when solving complex problems that benefit from code reuse.

Evolutionary algorithms (EAs) are population-based search algorithms that have been successfully applied to solve hard optimization problems in many application domains. Since the early 1990's researchers have begun to apply evolutionary algorithms to synthesize electronic circuits. Nowadays it is evident that the evolutionary design approach can automatically create efficient electronic circuits in many domains. In this tutorial, fundamental concepts of evolutionary design of digital circuits are presented. In particular, the tutorial deals with Cartesian Genetic Programming (CGP) — a method of genetic programming that in many cases outperforms conventional synthesis tools in terms of achievable circuit size reduction. Innovative designs will be presented in domains of small combinational circuits (where the goal is to minimize the number of gates), middle-size circuits (such as image filters intended for FPGAs where the goal is to obtain the quality of filtering of conventional methods for a significantly lower cost on a chip) and large circuits (such as benchmark circuits for comparison of testability analysis methods), covering thus circuit complexity from a few gates to millions of gates. For example, one of evolved image filters is now protected by utility model in the Czech Republic (patent pending). Evolved circuits will be compared with the best-known conventional designs. We will also show how to deal with the so-called scalability problems of evolutionary design which have been identified as the most important problems from the point of view of practical applications. In summary, tutorial participants will become familiar with the state of the art methods in the area of digital circuit evolution. They will learn how to apply CGP, construct the fitness function and run experiments.

Evolutionary design for energy-efficient approximate digital circuits

Cartesian Genetic Programming (CGP) is a graph-based genetic programming technique developed by Miller & Thompson in 2000 which has several advantages over the traditional form of tree-based Genetic programming (GP). In the standard form, CGP uses only mutation as a genetic operator whereas the use of traditional crossover operators of GP when applied to CGP led to disrupted results. Various researchers have come out with new genetic operators which when applied to standard CGP or its variants have given better results either in the form of better convergence or efficiency. In this paper, we performed a comparative evaluation of four genetic operators, namely standard crossover, Clegg’s crossover, Graph-based crossover, and forking operator, on standard CGP and tested them on standard benchmark datasets such as Koza-2, Koza-3, and Nguyen-2. Our evaluation shows that both Clegg’s crossover and forking operator performs better than the others.KeywordsSoft computingEvolutionary algorithmGenetic programmingGenetic operators

At present there is a wide range of evolutionary algorithms available to researchers and practitioners. Despite the great diversity of these algorithms, virtually all of the algorithms share one feature: they have been manually designed. Can evolutionary algorithms be designed automatically by computer? In this paper, a novel evolutionary algorithm based on automatically designing of genetic operators is presented to address this problem. The resulting algorithm not only explores solutions in the problem space, but also automatically generates genetic operators in the operator space for each generation. In order to verify the performance of the proposed algorithm, comprehensive experiments on 23 well-known benchmark optimization problems are conducted, and the results show that the proposed algorithm can outperform standard Differential Evolution (DE) algorithm.

The application of genetic and evolutionary computation to problems in medicine has increased rapidly over the past five years, but there are specific issues and challenges that distinguish it from other real-world applications. Obtaining reliable and coherent patient data, establishing the clinical need and demonstrating value in the results obtained are all aspects that require careful and detailed consideration. This tutorial is based on research which uses genetic programming (a representation of Cartesian Genetic Programming) in the diagnosis and monitoring of Parkinson's disease, Alzheimer's disease and other neurodegenerative conditions, as well as in the early detection of breast cancer through automated assessment of mammograms. The work is supported by multiple clinical studies in progress in the UK (Leeds General Infirmary), USA (UCSF), UAE (Dubai Rashid Hospital), Australia (Monash Medical Center) and Singapore (National Neuroscience Institute). The technology is protected through three patent applications and a University spin-out company marketing four medical devices. The tutorial considers the following topics: Introduction to medical applications of genetic and evolutionary computation and how these differ from other real-world applications Overview of past work in the from a medical and evolutionary computation point of view Three case examples of medical applications: i. diagnosis and monitoring of Parkinson's disease ii. detection of beast cancer from mammograms iii. cancer screening using Raman spectroscopy Practical advice on how to get started working on medical applications, including existing medical databases and conducting new medical studies, commercialization and protecting intellectual property. Summary, further reading and links

This chapter describes the use of biologically inspired Evolutionary Algorithms (EAs) to create designs for implementation on a reconfigurable logic device. Previous work on Evolvable Hardware (EHW) is discussed with a focus on timing problems for digital circuits. An EA is developed that describes the circuit using a Hardware Description Language (HDL) in a Cartesian Genetic Programming (CGP) framework. The use of an HDL enabled a commercial hardware simulator to be used to evaluate the evolved circuits. Timing models are included in the simulation allowing sequential circuits to be created and assessed. The aim of the work is to develop an EA that is able to create time dependent circuity using the versatility of a HDL and a hardware timing simulator. The variation in the circuit timing from the placement of the logic components, led to an environment with a selection pressure that promoted a more robust design. The results show the creation of both combinatorial and sequential circuits.

Dispatching rules are most commonly used to solve scheduling problems under dynamic conditions. Since designing new dispatching rules is a time-consuming process, it can be automated by using various machine learning and evolutionary computation methods. In previous research, genetic programming has been the most commonly used method for automatically designing new dispatching rules. However, there are many other evolutionary methods that use representations other than genetic programming that can be used to create dispatching rules. Some, such as gene expression programming, have already been used successfully, while others, such as Cartesian genetic programming or grammatical evolution, have not yet been used to generate dispatching rules. In this paper, six different methods (genetic programming, gene expression programming, Cartesian genetic programming, grammatical evolution, stack representation, and analytic programming) for generating dispatching rules for the unrelated machines environment are tested and the results for various scheduling criteria are analysed. It is also analysed how different individual sizes in the tested methods affect the performance and average size of the generated dispatching rules. The results show that, with the exception of grammatical evolution and analytic programming, all tested methods perform quite similarly, with results depending on the selected scheduling criterion. The results also show that Cartesian genetic programming is the most resistant to the occurrence of bloat and evolves dispatching rules with the smallest average size.

In this paper, two universal reinforcement learning methods are considered to solve the problem of maximum power point tracking for photovoltaics. Both methods exhibit fast achievement of the MPP under varying environmental conditions and are applicable in different PV systems. The only required knowledge of the PV system are the open-circuit voltage, the short-circuit current and the maximum power, all under STC, which are always provided by the manufacturer. Both methods are compared to a Fuzzy Logic Controller and the universality of the proposed methods is highlighted. After the implementation and the validation of proper performance of both methods, two evolutionary optimization algorithms (Big Bang—Big Crunch and Genetic Algorithm) are applied. The results demonstrate that both methods achieve higher energy production and in both methods the time for tracking the MPP is reduced, after the application of both evolutionary algorithms.

For problems involving uncertainties in design variables and parameters, a bi-objective evolutionary algorithm (EA) based approach to design optimization using evidence theory is proposed and implemented in this paper. In addition to a functional objective, a plausibility measure of failure of constraint satisfaction is minimized. Despite some interests in classical optimization literature, this is the first attempt to use evidence theory with an EA. Due to EA's flexibility in modifying its operators, nonrequirement of any gradient, its ability to handle multiple conflicting objectives, and ease of parallelization, evidence-based design optimization using an EA is promising. Results on a test problem and two engineering design problems show that the modified evolutionary multi-objective optimization algorithm is capable of finding a widely distributed trade-off frontier showing different optimal solutions corresponding to different levels of plausibility failure limits. Furthermore, a single-objective evidence-based EA is found to produce better optimal solutions than a previously reported classical optimization algorithm. Furthermore, the use of a graphical processing unit (GPU) based parallel computing platform demonstrates EA's performance enhancement around 160–700 times in implementing plausibility computations. Handling uncertainties of different types are getting increasingly popular in applied optimization studies and this EA based study is promising to be applied in real-world design optimization problems.

On the feasibility of using evolvable hardware for hardware Trojan detection and prevention

The application of pattern recognition techniques to radiology has the potential to detect cancer earlier and save lives, and consequently much research has been devoted to this problem. This worked tackled a subset of the problem, investigating a novel method of classifying mammograms using an evolutionary approach known as Cartesian genetic programming (CGP). Microcalcifications, one of two major indicators of cancer on mammograms, were used for the classification. A large software framework was written in order to investigate this, which allows the viewing of images, manual segmentation of lesions and then automatic classification. Two classification approaches were pursued, the first classifying on texture features and the second, a new approach, classifying by using the lesion's raw pixel array. Early results using the system showed some potential. It was found that during training, networks could obtain correct classification rates of between 80 and 100%. The best results were approaching those in the contemporary literature and suggest the technique warrants further investigation

Approximate computing along with quantized low-precision computing has gained significant interest in today’s neural network (NN) implementation. This paper proposes a library of VLSI implementations of different activation functions, aimed towards designing hardware-efficient NN accelerators. Cartesian genetic programming (CGP), an evolutionary algorithm was employed to generate gate-level designs of approximate and exact representations of activation functions. We open-source the hardware library of 9444 circuits containing a majority of the activation functions employed in NN architectures, including Sigmoid, Hyperbolic-Tangent, Gaussian, ReLU, GeLU, Softplus, and Binary-Step. The library also presents the error characteristics and hardware metrics of the designs which will aid in the usage of the library in future research. Additionally a hardware comparison of the proposed circuits against existing implementations including piecewise-linear (PWL), memory-based, hls4ml, DNNweaver implementations to realize activation functions on FPGA and ASIC flow is presented. The CGP evolved hardware library shows minimal silicon space requirement, least power consumption when investigated for ASIC flow, and the least LUT utilization’s in FPGA flow. Besides, SOMALib designs are purely combinatorial, allowing various synthesis stage optimizations towards the target Power-Performance-Area budget, which is not possible in standard memory block implementations.

Generating both accurate and diverse recommendations is required for modern recommender systems. Accurate recommendations can well meet the needs of users, while diverse recommendations can bring users novelty, discover the unknown preferences of users, and can also alleviate the long tail problem. However, these two metrics are conflicting and it is very hard to improve both at the same time. Thus, a compromise needs to be made. The easiest way is using hyperparameters to combine different objective functions or the recommendations of different recommendation algorithms, but it is difficult to determine parameters. Another common strategy is applying multi-objective evolutionary algorithm to provide multiple recommendations for each user, but how to choose the final recommendation becomes a new problem. To this end, we propose a two-phase evolutionary algorithm-based recommendation framework, named EARF. In EARF, a novel fitness function is designed, which converts the evaluation of accuracy and diversity into a single objective and automatically trades off these two goals. Based on the property of recommendation problem and fitness function, the genetic representation and operators are redefined. The experiments on real-world rating datasets indicate that the EARF is effective and the proposed evolutionary algorithm can achieve a good balance between accuracy and diversity.

In this paper, we propose a population-based, four-step, real-parameter optimization algorithm-generator. The approach divides the task of reaching near the optimum solution into four independent plans of (i) selecting good solutions from a solution base, (ii) generating new solutions using the selected solutions, (iii) choosing inferior or spurious solutions for replacement, and (iv) updating the solution base with good new or old solutions. Interestingly, many classical and evolutionary optimization algorithms are found to be representable by this algorithm-generator. The paper also recommends an efficient optimization algorithm with the possibility of using a number of different recombination plans and parameter values. With a systematic parametric study, the paper finally recommends a real-parameter optimization algorithm which outperforms a number of existing classical and evolutionary algorithms. To extend this study, the proposed algorithm-generator can be utilized to develop new and more efficient population-based optimization algorithms. The treatment of population-based classical and evolutionary optimization algorithms identically through the proposed algorithm-generator is the main hall-mark of this paper and should enable researchers from both classical and evolutionary fields to understand each other’s methods better and interact in a more coherent manner.