Bojan Mrazovac

A human detection method f or residential smart energy systems based on Zigbee RSSI changes

In this article, the device-free human presence detection method based on radio signal strength variations is proposed. The method exploits the known fact that human body interferes with radio signals by causing fading and shadowing effects. Introduced irregularities in the radio propagation pattern indicate possible presence of a human. The proposed method is incorporated into the existing platform for intelligent residential energy management. As opposed to conventional solutions which utilize a complex set of sensors for human detection, the proposed approach achieves the same only by analyzing and quantifying radio signal strength variations incorporated in messages exchanged between 2.4 GHz radio transceivers. One of the key benefits of the proposed solution is the integration of the detection algorithm into the smart power outlets and smart light switches. Such an approach improves interactions in smart home systems, enables intelligent power consumption management and low installation cost.

System Design for Passive Human Detection Using Principal Components of the Signal Strength Space

Radio irregularity phenomenon is often considered as a shortcoming of wireless sensor networks. In this paper, the radio irregularity is regarded as a benefit of wireless networks. The proposed novel method for human presence detection, applied to the monitoring system for residential energy management, utilizes radio irregularity for an efficient human presence detection which increases user awareness and automates the power control. The method monitors 2.4GHz wireless (Zigbee) smart outlets and the communication signals between them to detect changes of the received signal strength indicator (RSSI) and its variations compared to the expected mean values. The signal strength variation is significantly increased due to human presence within the signal propagation path. By applying the algorithm for principal components analysis to the set of RSSI samples obtained from radio communication links within the detection area, it is possible to recognize a human presence. There is no need for additional presence sensors installation, because the proposed method applied to the smart outlets network is quite satisfactory to extend the entire system with the detection capability. Compared to the conventional sensor networks, the presented solution preserves the pervasiveness of smart energy and smart home systems, high level of sensorial intelligence, simplicity and low installation costs.

Gesture based hardware interface for RF lighting control

Human interaction with wearable computers is a challenging research issue, especially when combined with augmented reality applications. Natural and unobtrusive interaction with various devices should be simple and at the same time intuitive for any user. This paper represents the design and implementation of a novel interactive hardware which recognizes certain hand gestures and responds in a way of controlling a remote light source. The hardware is made as a “sensing glove” which provides 3-dimensional light control for switching the light on/off or dimming to a desired level. Control parameters are calculated by an accelerometer mounted on the glove, which detects positions of a users palm in a 3D space. Slow palm rotation is translated into commands for the light dimming, whereas specific hand movements control the light switching. RF transmitter connected to the accelerometer sends the current palm and hand coordinates to the remote luminary. The luminary is managed by an RF receiver and a module for the light control which translates the received data into lighting commands.

Reaching the next level of indoor human presence detection: An RF based solution

The presence of a human in the vicinity of radio transceivers results in radio signal strength variations at the receivers input. Therefore, human presence in an indoor environment can be recognized by analyzing and quantifying irregularities in the radio signature. In order to quantify the information in terms of human presence, we present a novel human presence detection method based on information entropy extracted from a sequence of received signal strength samples. As opposed to existing smart home solutions that incorporate a complex set of sensors for human detection, the proposed method is solely based on radio irregularity phenomenon, without modifying the original environment. An additional level of sensor intelligence is introduced without sensors and installation costs, or specific training procedures for end-consumers.

Using radio irregularity for increasing residential energy awareness

Radio irregularity phenomenon is often considered as a shortcoming of wireless networks. In this paper we present the method of using radio irregularity as an efficient human presence detection sensor which increases user awareness in smart homes. The idea is based on monitoring the received signal strength indicator (RSSI) between stationary wireless (2.4 GHz — Zigbee) power outlets. When a human enters into the existing radio communication field, the signal can be absorbed, scattered or reflected by the body what results in strong variations of RSSI. Based on the detected changes compared to the initial values, the system detects human presence and responds with the automatic control of any appliance connected to outlets. Compared to conventional sensors, the proposed solution preserves the sensorial intelligence, simplicity and low installation costs without need for additional devices integration.

Evaluation of the available scripting languages for home automation networks: Real world case study

Ever increasing demand for the solutions that can help automate everyday tasks inside a household has resulted in various systems, devices and applications working towards the fulfilment of that goal. The majority of systems use scripting languages to define the behaviour of automated devices in the home. In this paper we present the results of the analysis of several major scripting languages used within a real home automation system, which we extended with several different script interpreters. In the scope of our discussions scripting languages Lua, XML and SMIL are covered.

Context-Aware Platform with User Availability Estimation and Light-Based Announcements

As the number of computer-based systems and consumer gadgets is growing, users are becoming increasingly overwhelmed by the requests for attention coming from this variety of devices. In addition, technology has quickened the pace of life and work to the extent that interaction between people has become more frequent. Dealing with both social and device-driven interruptions has become one of the important goals of context-aware systems of today. This paper proposes a context-aware platform that can help mitigate the negative effects of interruptions in human work and living. The platform uses a scalable set of sensors to estimate user availability in the home or office environment. This information is announced to possible interrupters (e.g., household members and software application) by using a web portal, lighting effects, or interfaces to a home automation system or any other interested entity in the local network. This paper presents several contributions to the field. Platform architecture is considered scalable enough to fit to a variety of todays consumer devices and smart home systems. The experiments were conducted to show the effectiveness of the platform usage within a living room area, as opposed to the traditional office contexts where the availability tends to be easier to determine. The last contribution is related to the novel method and the evaluation of the use of lighting announcements of availability instead of the traditional inefficient busy flags.

Performance evaluation of using Protocol Buffers in the Internet of Things communication

Things connected to the internet may not be connected only to servers on the cloud. Its usefulness can be unleashed only if they are interconnected as well. This interconnection is recognized as communication between services of the Internet of Things. Due to the nature of the things on the web, spatial overhead for any data exchanged needs to be kept to a minimum. JSON is recognized as a most efficient way to transfer various data in domain of distributed embedded systems. JSONs binary representation, BSON is even more preferable. This paper explores the possibilities and critically examines and evaluates the effectiveness of using Googles Protocol Buffer as a processing protocol and communication standard in transportation domain of the Internet of Things.

Cloud-enabled home automation gateway with the support for UPnP over IPv4/IPv6 and 6LoWPAN

The most recent requests for interoperability between the different devices within a home automation system have brought IP-based protocols to the attention in this area. However, a number of hurdles need to be overcome so that the IP connection to home devices could become enabled, the most important being the requests for a large address space and low power consumption. In this paper we present a solution of a home gateway device with the ability to interact with IPv6-enabled home devices over 6LoWPAN, with regard to the increased address space and low power consumption, respectively. Additionally, the gateway supports the traditional IPv4 interfacing over WiFi and Ethernet. UPnP over IPv6 is fully enabled so that all the devices can be easily found by UPnP discovery from any node in the network. Finally, the gateway populates the discovered devices to a cloud server, which in turn enables a variety of web applications for home control to interact to home devices by using asynchronous API calls.

Set-top box-based communication client with the automatic operation profile selection

The introduction of IP-based services to the realm of television broadcasting, television receivers and set-top boxes, opened possibilities for different, new applications for the users in front of their TV screens. IPTV, IP-based communications, social networking and web browsing are among the newest addons to the traditional digital TV concepts. This paper presents an integration concept and the implemented solution of a communication client application for a set-top box device. The communication client is provided as an add-on to the set-top box in the form of USB flash thumb drive. In addition to the voice call and messages, more advanced challenges are recognized and implemented for this application, with regard to the ubiquitous computing concept: context-aware features including an automatic profile selection based on the activities and the availability of people watching the TV, as calculated by the use of embedded sensors and proposed algorithms; the announcement of the selected profile by the use of RGB lighting effects for the RF-controlled RGB luminaires in the living room. These suggested features aim to improve the two most general usability problems of communication client applications applied to the specific set-top box solution. Firstly, interrupting the users by the notifications produced by the application can induce negative effects to user satisfaction and/or stress, if those notifications unexpectedly occur during engaging activities, such as watching the favorite TV show or talking to a friend in the room. Therefore, automatic profile selection based on detected user activities can mitigate these situations and provide the most suitable means of notifying the user for each specific situation of his/her engagement. Secondly, ignorance of the selected profile by other people interacting in person is accounted for by the announcement of the availability by using lighting stimuli.