IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards and specifies the set of medium access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) computer communication. The standard and amendments provide the basis for wireless network products using the Wi-Fi brand and are the world's most widely used wireless computer networking standards. IEEE 802.11 is used in most home and office networks to allow laptops, printers, smartphones, and other devices to communicate with each other and access the Internet without connecting wires.
Cyber-physical systems (CPS) are mechanisms controlled and monitored by computer algorithms, tightly integrated with the internet and its users. In cyber-physical systems, physical and software components are deeply intertwined, able to operate on different spatial and temporal scales, exhibit multiple and distinct behavioral modalities, and interact with each other in ways that change with context.
Energy Neutral Operation (ENO) is a mode of operation where the energy consumption of the sensor device is always less or equal than the energy harvested from the environment. Once in this state, the sensor systems can operate perpetually. To achieve energy neutral operation, energy optimization methods need to fulfil the energy neutrality constraints while either maintaining the application level of service or indeed achieve a best effort service, which aims to maximize performance.
Power from the People; Energy Harvesting Cedro Exchange Issue Number 2 - December 2012
1. Harvesting Energy from Human Power? There is a need for the conception, development and deployment of cost-effective renewable energy alternatives. The human body is a bank of stored energy: as we move to perform actions we convert this stored chemical potential energy into useful kinetic energy. What if we could harvest this energy? Many times, the human body is likened to a motor: turning potential energy into mechanical energy that can be used to perform work, but the intriguing feature of well-designed motors is that when the motor is run in the opposite direction it becomes a generator: converting mechanical energy back to potential energy. Through human power, we are exploiting this aspect of the human body: we are reversing the concept of the human body as a motor, instead using our body’s momentum as the mechanical energy that can be turned into potential energy. Theoretically, humans could be self-sufficient when it comes to energy generation, using nothing else than their own bodies. It is a striking realization that requires much reflection and thought. Human power has the advantages of being readily available at all times, requiring no chemical fuel or special logistical measures, and having little heat signature. It is shown that harvesting human energy not only uses wasted energy but also can actually improve biochemical efficiency through negative work cycles. This is much like «regenerative braking» for humans (Khaligh, 2009). There are two methods for harvesting energy from human power; active harvesting methods and passive harvesting methods, and these are shown in Figure 1.
