Kevin Warmerdam’s research while affiliated with Delft University of Technology and other places

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Publications (7)


Ten to 20 electrode placement system (http://commons.wikimedia.org/wiki/File:21_electrodes_of_International_10‐20_system_for_EEG.svg)
Neurosky mindwave mobile EEG headset
Alpha activity, transitioning from meditative to neutral state
Beta activity, transitioning from neutral to attentive state
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Mind your thoughts: BCI using single EEG electrode
  • Article
  • Full-text available

February 2019

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1,919 Reads

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23 Citations

Sujay Narayana

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Kevin Warmerdam

These days, the Internet of things (IoT) research is driving large-scale development and deployment of many innovative applications. IoT has indeed brought many smart applications to the doorstep of users. IoT has also made it possible to connect many sensors and control equipment. Here, the authors address an important application for physically challenged. The authors present a brain–computer interface (BCI) system to lock/unlock a wheelchair and control its movements using BCI. The approach presented here uses NeuroSky's MindWave Mobile, a single electrode electroencephalography (EEG) headset that can be connected to any Bluetooth-enabled system. The raw EEG data from the headset is processed on an Android mobile device to extract the electromyography (EMG) patterns that occur due to eye blinks and activity of muscles in the jaw. These patterns are used to control the movement of a wheelchair in all possible directions. A biometric security system is provided to lock and unlock the wheelchair by extracting the information about different brain waves from the raw EEG signal. In this system, only the user knows the password which is generated using brain waves and it can lock/unlock the wheelchair and control it. The proposed system was verified and evaluated using a prototype.

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Visible Light Communications for Sensing and Lighting Control

September 2016

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57 Reads

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22 Citations

IEEE Sensors Journal

Indoor lighting systems need to be designed to balance energy consumption and the visual comfort of occupants. Achieving this goal with multiple luminaires and sensors is, however, not a simple problem. Lighting control systems need to adjust the dimming levels of luminaires in real time based on occupancy conditions and external daylight changes. We propose a system based on visible light communication to monitor and control artificial lighting in a robust manner. In our system, luminaires modulate the emitted light to broadcast basic control information while fulfilling their main purpose of illumination. Based on the broadcasted information, luminaires use collocated light sensors to estimate the optical channel gains and daylight contributions. This information is then used in a control algorithm to determine the dimming levels of luminaires under specified illumination constraints. We provide an analytical framework, simulations, and an empirical evaluation of our approach in an office space. We compare our method with a state-of-art lighting control system that uses radio transceivers to communicate information, and thus, cannot monitor optical channels in real time. Our results show that while the radio-based system may underilluminate and even oscillate around the desired illumination due to large reflectance changes in the environment, our method provides stable illumination close to desired levels.


Connectivity in IoT indoor lighting systems with visible light communications

November 2015

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52 Reads

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38 Citations

An Internet of Things (IoT) indoor lighting system that consists of multiple luminaires with an IP address, sensors and controllers is considered. The sensors provide sensing information for controlling artificial lighting system and additionally serve as a data source for other building systems and services. In this paper, we consider visible light communication (VLC) among sensors and luminaires for providing connectivity across these elements. Such connectivity enables data access via the luminaires that have a unique IP address. To enable connected applications such as lighting control and device positioning, we propose methods for estimating the optical channel gains and daylight contribution. Analytical results on packet error rate of VLC communication and estimation performance are obtained and verified with simulations and experiments in an office lighting testbed.


Occupancy analytics using RSSI information on wireless lighting systems

July 2015

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20 Reads

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1 Citation

Occupancy analytics refers to statistical analysis related to occupancy of users in a building to derive information and insights based on which control and management of building systems may be improved. We consider the use of a wireless sensors infrastructure in a lighting system to derive occupancy analytics. Specifically, radio received signal strength indicator (RSSI) values at wireless motion and light sensors are used that result from transmissions of user devices. Statistical methods are proposed to derive occupancy metrics: occupancy density, area usage, and occupant dwell times. We evaluate the performance of the proposed approach using an open-plan office wireless lighting control model.


Managing tethered data traffic over a hotspot network

January 2015

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23 Reads

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1 Citation

Dzung Tran

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Kevin Warmerdam

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Thanh Lim

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[...]

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Bikramjit Singh

Presented is a system and method for controlling access to a mobile hotspot on a mobile device utilizing a hotspot management application. The method includes detecting unauthorized data traffic over a tethered link between the mobile device and a tethered device by analyzing a signature of the unauthorized data traffic. Analyzing the signature of the unauthorized data traffic may be carried out utilizing a rules engine, where the rules engine is based on one or more carrier controlled tethering policies and one or more user controlled tethering policies. Detecting unauthorized data traffic may further include detecting an unauthorized tethering application on the mobile device utilizing a database of known unauthorized tethering applications. The method further includes controlling the unauthorized data traffic. The method additionally includes redirecting a user of the mobile device to a captive portal for authorized tethering plan support.


Location Data Analytics in Wireless Lighting Systems

January 2015

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32 Reads

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11 Citations

IEEE Sensors Journal

Location data analytics refers to the statistical analysis of data pertaining to user location. Such analytics offers useful insights into the interactions among occupants and with their environment. Based on the insights, building facility management may be improved. We consider location data analytics using wireless sensors, which are part of a wireless lighting system, to collect radio received signal strength indicator data resulting from device transmissions from user mobile devices. Zone positioning of users is first performed. Zone position data are then used for analytics to obtain: 1) occupancy density; 2) environment characterization; 3) crowd detection; and 4) occupant connectivity. The approach is evaluated in a simulated open-plan office lighting environment considering simple occupant motion profiles and wireless device transmission models.


Device API for securely monitoring and managing mobile broadband devices

September 2014

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10 Reads

There is provided a device application programming interface (API) for securely monitoring and managing mobile broadband devices. There is provided a client device with a processor configured to detect, using an API, the WWAN device, wherein the WWAN device conforms to the API, to perform a mutual authentication with the WWAN device by using a digital certificate of the WWAN device and a client digital certificate of the client device, to establish a secure connection with the WWAN device upon a successful authentication of the mutual authentication with the WWAN device. Moreover, the processor may be configured to issue, using the API, various commands to the WWAN device to monitor and manage the WWAN device.

Citations (5)


... Utilizing portable systems greatly simplifies the process of recording electroencephalography (EEG) in both indoor and outdoor settings, particularly for applications involving brain-computer interfaces (BCI). For extended patient monitoring, prefrontal EEG recordings are predominantly favoured [1], and these find numerous applications [2][3][4][5][6]. Typically, recorded EEG data is susceptible to contamination from both physiological sources (such as cardiac and neural fluctuations) and non-physiological factors (like electrode pops, electrical shifts, and linear trend artifacts) [7,8]. ...

Reference:

VME-EFD : A novel framework to eliminate the Electrooculogram artifact from single-channel EEGs
Mind your thoughts: BCI using single EEG electrode

... Compared with traditional radio frequency communication, VLC technology has both lighting and communication functions and has the advantages of a high transmission rate, no spectrum limitation, safety, green, etc. These advantages make it play an important role in the fields of high-speed positioning, sensing, and the Internet of Things [3,4]. ...

Visible Light Communications for Sensing and Lighting Control
  • Citing Article
  • September 2016

IEEE Sensors Journal

... Indoor OWC systems operating in visible spectrum, called visible light communications (VLC), represent an efficient alternative to the RF systems, since they provide very high-speed, green and secure transmission [16]- [19]. The VLC-based indoor IoT systems have been analyzed in [19]- [23]. In order to ensure throughput-efficient link in optical IoT networks, different multiple access approaches have been analyzed [24]- [27]. ...

Connectivity in IoT indoor lighting systems with visible light communications
  • Citing Conference Paper
  • November 2015

... The authors of [199] shed light on power consumption reduction via energy-efficient smart lighting systems. Today's smart building employs low-power usage LED-based light sources that last longer than Compact Fluorescent Lamps (CFLs) [200]. In reality, the development of control technologies, heterogeneous networks, and embedded systems has made it promising to create smart innovative lighting systems that can effectively address the problem of energy conservation. ...

Location Data Analytics in Wireless Lighting Systems
  • Citing Article
  • January 2015

IEEE Sensors Journal