An adaptive observer for Lorenz chaotic system

Doğrusal olmayan sistemler için önerilmiş bir adaptif gözleyici tasarım yöntemi, kaotik salınımlar üreten Lorenz sistemi üzerinde başarı ile uygulanmıştır. Geribesleme bu gözleyici tarafından doğrudan kullanılmayıp sadece adaptasyon algoritmasında doğrudan doğruya kullanılmaktadır. Üçüncü mertebeden ve üç parametreli bu sistemin parametrelerinden birisinin bilinmediği ve durum değişkenlerinden sadece birisinin erişilebilir olduğu kabul edilmiştir. Hem durum değişkenleri hem de bilinmeyen parametrenin bu yöntemle tahmin edilmesi simülasyon sonuçları ile gösterilmiştir. Bu gözleyici gizli haberleşme sistemlerine uygulanırsa iki farklı bilgi sinyalinin aynı kaotik sinyal üzerinden gönderilmesi mümkün olacaktır.An adaptive observer design technique proposed for nonlinear systems have been successfully applied to the Lorenz system, which produces chaotic oscillations. This observer does not use any feedback directly. The feedback is directly utilised only in the adaptation algorithm. It is assumed for this third order system with three parameters that only one of the state variables is accessible and one of the parameters is unknown. Estimation of all the state variables and the unknown parameter has been shown with simulation results using this method. If this observer is applied to secure communication systems, it will be possible to transmit two different information signals over the same chaotic signal

Design and implementation of a multi-modal sensor with on-chip security

With the advancement of technology, wearable devices for fitness tracking, patient monitoring, diagnosis, and disease prevention are finding ways to be woven into modern world reality. CMOS sensors are known to be compact, with low power consumption, making them an inseparable part of wireless medical applications and Internet of Things (IoT). Digital/semi-digital output, by the translation of transmitting data into the frequency domain, takes advantages of both the analog and digital world. However, one of the most critical measures of communication, security, is ignored and not considered for fabrication of an integrated chip. With the advancement of Moore\u27s law and the possibility of having a higher number of transistors and more complex circuits, the feasibility of having on-chip security measures is drawing more attention. One of the fundamental means of secure communication is real-time encryption. Encryption/ciphering occurs when we encode a signal or data, and prevents unauthorized parties from reading or understanding this information. Encryption is the process of transmitting sensitive data securely and with privacy. This measure of security is essential since in biomedical devices, the attacker/hacker can endanger users of IoT or wearable sensors (e.g. attacks at implanted biosensors can cause fatal harm to the user). This work develops 1) A low power and compact multi-modal sensor that can measure temperature and impedance with a quasi-digital output and 2) a low power on-chip signal cipher for real-time data transfer