The problem and the concept of substance are considered to be one of the basic and perennial subjects in philosophy. It takes an important place within philosophy both epistemologically and ontologically, and most philosophers have discussed it in their works. In his book, A Survey Concerning Human Understanding, John LOCK, the father of empirical philosophy in England, has discussed the concept of substance and how it is conceptualized in the mind, and through that, he has come to believe in their independent existence. According to him, the concept of substance is originated from a supposition and a rational inference: that the qualities cannot be self-existent. He believes that we have no notion of substance in mind, save a substratum upon which the accidents stand. So the concept of substance is not known through experience at all whether the experience is a sensation or a reflection. Therefore in believing in the concept of substance, LOCK has ignored his empirical principles, as he has ignored his empirical method in believing in its objectivity, because he does not believe in any kind of a priori concepts or judgments. In this paper, however, we will offer an empirical understanding of the concept of substance; a point that was not intuited by LOCK. In this view, the concept of substance is considered empirical, but believing in its independent existence based on an a priori rational principle is regarded as violating the empirical principle that no a priori principle exists. Thus, on the basis of LOCK's empiricism we can believe in the concept of substance but not in its external existence.

Minimal stopping distance, guaranteed steering ability and stability are the three most important purposes in Anti-LOCK Braking System (ABS) realm. The ABS system is a nonlinear, time variant and multivariable system with some uncertainties. Some research work has been carried out on ABS control systems using intricate methods, which are expensive to implement. In this paper at the first step, the system interference is decreased via decoupling matrix and the ABS is controlled with a robust diagonal controller. In fact, a decentralized control technique is used for our ABS control mechanism. At the second step, we exploit a multivariable technique in linear control to attack the problem.This is the Designed Linear Control with Multivariable Technique. The Optimal Eigenstructure assignment with the Genetic Algorithm (GA) method is also applied. Simulation and comparison studies are used to show the effectiveness of the proposed methods.

A new anti-LOCK braking system (ABS) for motorcycles is proposed in this study. It functions by processing the speed of the motorcycle tire in contact with the ground relative to the speed of the motorcycle itself and by calculating the slip ratio (l) of the tire slipping on the ground while braking, and reducing it to a minimum which leads to increased controllability of the motorcycle and reduction of the stopping distance, especially when the ground is slippery. The design of the new ABS and its pilot model comprises mechanical parts, hydraulics, and an electrical circuit. The pilot model providing the testing facility for the brake system functioning in a fixed place is in fact a simulation of the movement of a motorcycle on the ground. When the electric motor is turned on, and its flywheel reaches the desired speed, a controllable load is applied to the flywheel by the motorcycle tire which is a modelling of the weight of the motorcycle and the rider. Then, by turning the electric motor off, the throttle is released and the brake is activated. In this state, without the tire being LOCKed, it will stop within a shorter time and distance than the non-ABS, because the new system keeps the tire in the threshold state of slipping relative to the ground, which is the maximum friction coefficient and the maximum brake force. The results show that the stoppage time for the new ABS is about 40% less than that is the non-ABS type.