Mainly using a differential pair, we analyze the properties of a symmetrical circuit diagram; conversely we try to reinvent the differential pair from scratch using these properties. Through this process, we will give some examples of utilizing the symmetry of a circuit to realize the necessary electrical input-output functions. We thus demonstrate the usefulness and beauty of the symmetry.

A multiple-valued logic function is a multivariable function whose input and output are in a finite field and is applied to the construction of switching circuits. A multiple-valued logic polynomial is a multivariable polynomial with coefficients in a finite field. It is known that multiple-valued logic functions are equal to multiple-valued logic polynomials. Because error-correcting codes and multiple-valued logic polynomials have a dual relationship with each other, the research results of error-correcting codes can be employed to multiple-valued logic polynomials. In this study, a generalized “convolution theorem” is described, which is a relationship between multiple-valued logic functions and polynomials through discrete Fourier transforms, and it is generalized to a subset of finite fields called a semigroup. Next, this theorem is applied to speed up the multiplication of multiple-valued logic polynomials. Finally, to show a relationship between multiple-valued logic functions and error-correcting codes, a method of explicitly obtaining dual codes is given.

Networked structures can be found in various important applications including communication networks, social networks, and transportation networks. A complex network structure often yields a large-scale dynamical system by connecting possibly simple and low-dimensional dynamical systems. To effectively analyze and control a large-scale dynamical system as a whole, it is of practical importance to develop a methodology for efficiently distributing control resources over a complex network structure. In this context, this article gives an overview of convex-optimization-based approaches for effectively distributing medical and social resources toward the containment of a disease spread over human social networks.

In this article. I examine ethical issues surrounding combat drones, including autonomous ones, as one of the case studies of war ethics or the ethics of war, which is one of the disciplines of applied ethics. The main body of this article consists of 4 sections (Sections 2-5). In Section 2, I will provide a brief overview of war ethics. In Section 3, I will sketch an outline of ‘just war theory’, which is one of the mainstream approaches, along with political realism and pacifism in war ethics. In Section 4, I will introduce several topics and issues, currently being discussed in war ethics. In Section 5, I will conclude by illustrating a hopefully counterfactual dystopian future where fully autonomous combat drones are frequently used as a method of attack.