System Design of Internet-of-Things for Residential Smart Grid

Internet-of-Things (IoTs) envisions to integrate, coordinate, communicate, and collaborate real-world objects in order to perform daily tasks in a more intelligent and efficient manner. To comprehend this vision, this paper studies the design of a large scale IoT system for smart grid application, which constitutes a large number of home users and has the requirement of fast response time. In particular, we focus on the messaging protocol of a universal IoT home gateway, where our cloud enabled system consists of a backend server, unified home gateway (UHG) at the end users, and user interface for mobile devices. We discuss the features of such IoT system to support a large scale deployment with a UHG and real-time residential smart grid applications. Based on the requirements, we design an IoT system using the XMPP protocol, and implemented in a testbed for energy management applications. To show the effectiveness of the designed testbed, we present some results using the proposed IoT architecture.Comment: 10 pages, 6 figures, journal pape

The Multi-shadow Analysis of LED Secondary Optics

AbstractDue to these advantages, small size, low heat radiation, long life time, and high luminous efficiency, the light-emitting diodes (LEDs) have been used widely to the varied lighting in recent years. However, the LEDs have the higher intensity of light in central region and the scattering in the surrounding during lighting, so it is necessary to modify the LED projection by the secondary optical lens. The extra secondary optical lens can enhance the light collection efficiency of LED, but it will readily induce the multi-shadow phenomenon during lighting, which has a significant impact on the human vision. In this study, the LED illumination module with/without secondary optical lens, total internal reflected (TIR) lens or reflection mirror cup, can be simulated by the Apilux(R) optical software. The result indicates that the approach can identify the level of multi-shadow images according to the deviations in light intensity, and will be new performance criteria of LEDs for users

Developing new heat pump system to improve indoor living space in senior long-term care house

The issue of an aging population is becoming increasingly acute in Taiwan; in 2018, seniors comprised over 14 % of the total population. The quality of care for senior citizens hinges on the ability of long-term care facilities to create comfortable living spaces while ensuring energy efficiency by reducing electricity consumption, thereby providing them with an environment for aging in an active and positive way. This study proposes a new heat pump system that offers a cold source in the summer and a heat source in the winter. In addition, the air-conditioning and ventilation rates required for comfort in indoor living spaces are established to ensure the high quality of the care spaces in these types of institutions. The results after installation of the heat pump system were as follows: (1) Performance of the heat pump system: the inlet temperature of the heat pump chilled water was maintained at 7-10 °C, and the outlet temperature, at 42-54 °C. (2) Energy efficiency: Based on a 95 % confidence interval, the average annual electricity consumption was 32.65 kwh/day, which was 32.65 % of the prior consumption level; the reduction of 67.35 % is comparable to those of most heat pump systems. (3) Improvement of the indoor environment: In the hottest scenario, the indoor temperature was reduced by 3 °C and the relative humidity to 55-65 %, which fall within comfortable ranges. After the heat pump system was introduced, significant improvements in ventilation, air quality and comfort were noted, as well as significant improvement in average total satisfaction scores. All improvements reached statistical significance. The overall objective of the system is to enhance the environmental quality in long-term senior care facilities and make them healthier and more energy efficient

Extracting energy via magnetic reconnection from Kerr-de Sitter black holes

It has been recently shown that magnetic reconnection can provide us a novel mechanism to extract black hole rotational energy from a Kerr black holes. In some certain values of parameters, such mechanism is found to be more efficient than the Blandford-Znajek mechanism. In this paper, we study the energy extraction from the Kerr-de Sitter black hole via this magnetic reconnection process. With the increase of the cosmological constant, a slowly spinning Kerr-de Sitter black hole can implement the energy extraction than its Kerr counterpart. Of particular interest is that although the numerical calculation shows that the maximum values of the power and efficiency decrease with the cosmological constant, Kerr-de Sitter black hole still has advantages when the black hole spin $a/M>1$ and the dominant reconnection $X$-point is far away from the event horizon. These results uncover the significant effects of cosmological constant on the energy extraction via the magnetic reconnection process.Comment: 16 pages, 11 figure