| 1. |
|
|
| 2. |
- Pérez-Penichet, Carlos, et al.
(författare)
-
Poster abstract : Augmenting WSNs with interoperable 802.15.4 sensor tags
- 2017
-
Ingår i: SenSys 2017 - Proceedings of the 15th ACM Conference on Embedded Networked Sensor Systems. - New York, NY, USA : Association for Computing Machinery, Inc. - 9781450354592
-
Konferensbidrag (refereegranskat)abstract
- The sensing capabilities of most sensor networks are fixed at the time of deployment. Adding new sensing capabilities to such networks is a costly and cumbersome process. We present Passive Sensor Tags, battery-free sensing devices that could be used to extend the sensing capabilities of an existing network. Sensor tags feature our new 802.15.4 receiver design which is suitable for micro-power operation, making battery-free tags possible. Because our tags can both transmit and receive 802.15.4 frames there is no need for any modification to the deployed hardware. We present preliminary measurements of transmission and reception range.
|
|
| 3. |
- Halvarsson, Björn, et al.
(författare)
-
A New Input/Output Pairing Strategy based on Linear Quadratic Gaussian Control
- 2009
-
Ingår i: Proc. 7th IEEE International Conference on Control and Automation, Dec. 9-11, Christchurch, New Zealand. - Piscataway, NJ : IEEE. - 9781424447060 ; , s. 978-982
-
Konferensbidrag (refereegranskat)abstract
- In this paper a new input/output pairing strategy based on linear quadratic Gaussian control (LQG) is suggested. The strategy is used to compare the expected performance of decentralized control structures in some illustrative examples. The pairing suggestions are compared with the recommendations previously obtained using other interaction measures such as the Relative Gain Array (RGA). The new strategy gives suitable pairing recommendations and is easy to interpret.
|
|
| 4. |
- Cindemir, Umut, et al.
(författare)
-
Porous Nickel Oxide Sensor for Formaldehyde Detection
- 2014
-
Ingår i: European Materials Society (E-MRS) Spring Meeting, Lille, France, May 26-30, 2014..
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Formaldehyde is a volatile organic compound, which is a harmful indoor pollutant, causing sick building syndrome (SBS) and is released from household and building materials. Since higher concentrations of formaldehyde are considered to be carcinogenic, monitoring them indoors is of great importance. Advanced gas deposition has here been used to fabricate highly porous nickel oxide (NiO) thin films for formaldehyde sensing. The films were deposited on Al2O3 substrates with prefabricated comb-structured electrodes, and a resistive heater at the opposite face. The morphology of the films was investigated with scanning electron microscopy, and the porosity was determined by nitrogen adsorption isotherms with the Brunauer-Emmett-Teller method. The particle size was found to be less than 10 nm, as determined by x-ray diffraction. X-ray photoelectron spectroscopy of the NiO films was also done. Gas sensing measurements were done using a total gas flow rate of 200 ml/min. Resistivity values of sensors were recorded with formaldehyde diluted in synthetic air. Sensor resistances were recorded at 50 ppm, 25ppm, 10ppm and 5 ppm formaldehyde concentration. NiO films showed promising formaldehyde gas sensing properties implying lower levels of detection limit.
|
|
| 5. |
- Flores-García, Erik, et al.
(författare)
-
Characterizing Digital Dashboards for Smart Production Logistics
- 2022
-
Ingår i: Advances in Production Management Systems. Smart Manufacturing and Logistics Systems: Turning Ideas into Action. - Cham : Springer Nature Switzerland AG. - 9783031164101 - 9783031164118 ; , s. 521-528, s. 521-528
-
Konferensbidrag (refereegranskat)abstract
- Developing digital dashboards (DD) that support staff in monitoring, identifying anomalies, and facilitating corrective actions are decisive for achieving the benefits of Smart Production Logistics (SPL). However, existing literature about SPL has not sufficiently investigated the characteristics of DD allowing staff to enhance operational performance. This conceptual study identifies the characteristics of DD in SPL for enhancing operational performance of material handling. The study presents preliminary findings from an ongoing laboratory development, and identifies six characteristics of DD. These include monitoring, analysis, prediction, identification, recommendation, and control. The study discusses the implications of these characteristics when applied to energy consumption, makespan, on-time delivery, and status for material handling. The study proposes the prototype of a DD in a laboratory environment involving Autonomous Mobile Robots.
|
|
| 6. |
- Hägglund, Carl, 1975-
(författare)
-
Ultrathin metal-semiconductor nanocomposites as resource efficient light absorbers for photovoltaics
- 2014
-
Konferensbidrag (refereegranskat)abstract
- The light absorbing semiconductor layers of solar cells are traditionally made to absorb nearly all photons with energies exceeding the bandgap, more or less through choice of thickness according to the inverse of the absorption coefficient. A drastically different approach is to design a nanocomposite material with effective optical constants such that they approach the ideal conditions for light absorption for a given, very small thickness. By combining semiconducting layers suitable for solar energy conversion with noble metal nanoparticles supporting localized surface plasmon resonances in the visible to near infrared range, it has been theoretically and experimentally demonstrated that such conditions can readily be accomplished with mass equivalent thicknesses on the nanoscale. Effective absorption coefficients exceeding 1 nm-1, or an order of magnitude higher than for bulk metals, were observed.1 In order to exploit the light absorption in such nanocomposites for efficient solar energy conversion, several important challenges must be successfully addressed. Firstly, the absorption must cover a broad spectral range, typically between 2 and 3 eV in width depending on bandgap. Further, losses in the form of Joule heating of the metal component must be minimized. Finally, efficient charge carrier separation must be accomplished. One approach that may prove useful in these regards is to exploit plasmon near-field induced absorption in a strongly coupled, highly damped semiconductor material.2 A high damping of the plasmon resonance both broadens the absorption peak and causes a high fraction of the absorption to take place in the semiconductor layer, thus avoiding Joule heating and producing more long lived electron hole pairs that can feasibly be separated with higher yield. Recent experimental results in this area, based on ultrathin semiconductor layers grown on metal nanoparticle arrays by atomic layer deposition, will be presented. 1 Hägglund, C., Zeltzer, G., Ruiz, R., Thomann, I., Lee, H.-B.-R., Brongersma, M. L. & Bent, S. F. Self-assembly based plasmonic arrays tuned by atomic layer deposition for extreme visible light absorption. Nano Lett. 13, 3352-3357 (2013). DOI: 10.1021/nl401641v2 Hägglund, C. & Apell, S. P. Plasmonic near-field absorbers for ultrathin solar cells. The Journal of Physical Chemistry Letters 3, 1275-1285 (2012). DOI: 10.1021/jz300290d
|
|
| 7. |
- Mazzotta, Francesco, 1985, et al.
(författare)
-
Nanoplasmonic biosensing with on-chip electrical detection
- 2010
-
Ingår i: Biosensors and Bioelectronics. - : Elsevier BV. - 0956-5663 .- 1873-4235. ; 26:4, s. 1131-1136
-
Konferensbidrag (refereegranskat)abstract
- A nanoplasmonic biosensor chip with integrated electrical detection is presented. The concept is based on the local refractive index sensitivity of nanoplasmonic gold nanodisks (110 nm in diameter and 20 nm in height) that are fabricated, through a parallel method, directly on an array of silicon solar cells or photoactive diodes. The nanoplasmonic properties of the sensor chip were investigated both optically and electrically, with excellent agreement between the two. We show that local changes in the refractive index of the surrounding environment gives changes in the nanoplasmonic properties of the gold nanodisks, which induce corresponding changes in the photocurrent at single wavelengths of the nanoplasmonic solar cells. With a simple light-emitting diode as light source, and together with a material-specific modification protocol, the photocurrent output of the nanoplasmonic sensor chip was successfully used to monitor a specific biorecognition reaction in real-time.
|
|
| 8. |
- Österlund, Lars, 1967-, et al.
(författare)
-
Photocatalytic oxide films in the built environment
- 2014
-
Ingår i: INERA Workshop: Transition Metal Oxide Thin Films-functional Layers in "Smart windows" and Water Splitting Devices. - : Institute of Physics (IOP). ; , s. 012009-
-
Konferensbidrag (refereegranskat)abstract
- The possibility to increase human comfort in buildings is a powerful driving force for the introduction of new technology. Among other things our sense of comfort depends on air quality, temperature, lighting level, and the possibility of having visual contact between indoors and outdoors. Indeed there is an intimate connection between energy, comfort, and health issues in the built environment, leading to a need for intelligent building materials and green architecture. Photocatalytic materials can be applied as coatings, filters, and be embedded in building materials to provide self-cleaning, antibacterial, air cleaning, deodorizing, and water cleaning functions utilizing either solar light or artificial illumination sources – either already present in buildings, or by purposefully designed luminaries. Huge improvements in indoor comfort can thus be made, and also alleviate negative health effects associated with buildings, such as the sick-house syndrome. At the same time huge cost savings can be made by reducing maintenance costs. Photocatalytic oxides can be chemical modified by changing their acid-base surface properties, which can be used to overcome deactivation problems commonly encountered for TiO2 in air cleaning applications [2, 3]. In addition, the wetting properties oxides can be tailored by surface chemical modifications and made e.g. oleophobic and water repellent [5]. Here we show results of surface acid modified TiO2 coatings on various substrates. In particular, we show that advanced surface treatment of photocatalytic cement yields surfaces with beneficial self-cleaning properties by means of photo-fixation of surface sulfate groups. We propose that such approaches are feasible for a number of applications in the built environment, including windows, tiles, sheet metals, plastics, etc.
|
|
| 9. |
- Al Nahas, Beshr, 1985, et al.
(författare)
-
Low-power listening goes multi-channel
- 2014
-
Ingår i: Proceedings - IEEE International Conference on Distributed Computing in Sensor Systems, DCOSS 2014. ; , s. 2-9
-
Konferensbidrag (refereegranskat)abstract
- Exploiting multiple radio channels for communication has been long known as a practical way to mitigate interference in wireless settings. In Wireless Sensor Networks, however, multi-channel solutions have not reached their full potential: the MAC layers included in TinyOS or the Contiki OS for example are mostly single-channel. The literature offers a number of interesting solutions, but experimental results were often too few to build confidence. We propose a practical extension of low-power listening, MiCMAC, that performs channel hopping, operates in a distributed way, and is independent of upper layers of the protocol stack. The above properties make it easy to deploy in a variety of scenarios, without any extra configuration/scheduling/channel selection hassle. We implement our solution in Contiki and evaluate it in a 97-node~testbed while running a complete, out-of-the-box low-power IPv6 communication stack (UDP/RPL/6LoWPAN). Our experimental results demonstrate increased resilience to emulated WiFi interference (e.g., data yield kept above 90% when Contiki MAC drops in the 40% range). In noiseless environments, MiCMAC keeps the overhead low in comparison to Contiki MAC, achieving performance as high as 99% data yield along with sub-percent duty cycle and sub-second latency for a 1-minute inter-packet interval data collection. © 2014 IEEE.
|
|
| 10. |
- Feeney, Laura Marie, et al.
(författare)
-
Poster Abstract: Preliminary results on LoRaWAN and IEEE 802.15.4-SUN Interference
- 2018
-
Ingår i: SenSys '18. - Shenzhen, China : ACM. - 9781450359528 ; , s. 430-431
-
Konferensbidrag (refereegranskat)abstract
- We present some preliminary results on LoRaWAN and IEEE 802.15.4- SUN interference in urban environments. The results are based on a simple simulation that is parameterized using PHY layer measurements of controlled interference scenarios
|
|
