| 1. |
- Mohamed, S. A. S., et al.
(författare)
-
Asynchronous Corner Tracking Algorithm Based on Lifetime of Events for DAVIS Cameras
- 2020
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Ingår i: 15th International Symposium on Visual Computing, ISVC 2020. - Cham : Springer Science and Business Media Deutschland GmbH. ; , s. 530-541
-
Konferensbidrag (refereegranskat)abstract
- Event cameras, i.e., the Dynamic and Active-pixel Vision Sensor (DAVIS) ones, capture the intensity changes in the scene and generates a stream of events in an asynchronous fashion. The output rate of such cameras can reach up to 10 million events per second in high dynamic environments. DAVIS cameras use novel vision sensors that mimic human eyes. Their attractive attributes, such as high output rate, High Dynamic Range (HDR), and high pixel bandwidth, make them an ideal solution for applications that require high-frequency tracking. Moreover, applications that operate in challenging lighting scenarios can exploit from the high HDR of event cameras, i.e., 140 dB compared to 60 dB of traditional cameras. In this paper, a novel asynchronous corner tracking method is proposed that uses both events and intensity images captured by a DAVIS camera. The Harris algorithm is used to extract features, i.e., frame-corners from keyframes, i.e., intensity images. Afterward, a matching algorithm is used to extract event-corners from the stream of events. Events are solely used to perform asynchronous tracking until the next keyframe is captured. Neighboring events, within a window size of 5 × 5 pixels around the event-corner, are used to calculate the velocity and direction of extracted event-corners by fitting the 2D planar using a randomized Hough transform algorithm. Experimental evaluation showed that our approach is able to update the location of the extracted corners up to 100 times during the blind time of traditional cameras, i.e., between two consecutive intensity images.
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| 2. |
- Mohamed, S. A. S., et al.
(författare)
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DBA-Filter : A Dynamic Background Activity Noise Filtering Algorithm for Event Cameras
- 2022
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Ingår i: Proceedings of the 2021 Computing Conference, Volume 1. - Cham : Springer Science and Business Media Deutschland GmbH. ; , s. 685-696
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Konferensbidrag (refereegranskat)abstract
- Newly emerged dynamic vision sensors (DVS) offer a great potential over traditional sensors (e.g. CMOS) since they have a high temporal resolution in the order of μs, ultra-low power consumption and high dynamic range up to 140 dB compared to 60 dB in frame cameras. Unlike traditional cameras, the output of DVS cameras is a stream of events that encodes the location of the pixel, time, and polarity of the brightness change. An event is triggered when the change of brightness, i.e. log intensity, of a pixel exceeds a certain threshold. The output of event cameras often contains a significant amount of noise (outlier events) alongside the signal (inlier events). The main cause of that is transistor switch leakage and noise. This paper presents a dynamic background activity filtering, called DBA-filter, for event cameras based on an adaptation of the K-nearest neighbor (KNN) algorithm and the optical flow. Results show that the proposed algorithm is able to achieve a high signal to noise ratio up to 13.64 dB.
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| 3. |
- Mohamed, S. A. S., et al.
(författare)
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Dynamic resource-aware corner detection for bio-inspired vision sensors
- 2020
-
Ingår i: 2020 25th International Conference on Pattern Recognition, (ICPR). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 10465-10472
-
Konferensbidrag (refereegranskat)abstract
- Event-based cameras are vision devices that transmit only brightness changes with low latency and ultra-low power consumption. Such characteristics make event-based cameras attractive in the field of localization and object tracking in resource-constrained systems. Since the number of generated events in such cameras is huge, the selection and filtering of the incoming events are beneficial from both increasing the accuracy of the features and reducing the computational load. In this paper, we present an algorithm to detect asynchronous corners form a stream of events in real-time on embedded systems. The algorithm is called the Three Layer Filtering-Harris or TLF-Harris algorithm. The algorithm is based on an events' filtering strategy whose purpose is 1) to increase the accuracy by deliberately eliminating some incoming events, i.e., noise and 2) to improve the real-time performance of the system, i.e., preserving a constant throughput in terms of input events per second, by discarding unnecessary events with a limited accuracy loss. An approximation of the Harris algorithm, in turn, is used to exploit its high-quality detection capability with a low-complexity implementation to enable seamless real-time performance on embedded computing platforms. The proposed algorithm is capable of selecting the best corner candidate among neighbors and achieves an average execution time savings of 59% compared with the conventional Harris score. Moreover, our approach outperforms the competing methods, such as eFAST, eHarris, and FA-Harris, in terms of real-time performance, and surpasses Arc* in terms of accuracy.
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| 4. |
- Nurmi, J, et al.
(författare)
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The SoC-mobinet model in system-on-chip education
- 2005
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Ingår i: 2005 IEEE International Conference on Microelectronic Systems Education, Proceedings. - LOS ALAMITOS, CA : IEEE COMPUTER SOC. - 0769523749 ; , s. 71-72
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Konferensbidrag (refereegranskat)abstract
- This paper describes the model of developing SoC curricula jointly by industry and academia, where joint effort research results are turned into course contents for SoC-curricula and industry training activities.
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| 5. |
- Ofner, Erwin, et al.
(författare)
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SoC-Mobinet, R&D and Education in System-on-Chip Design
- 2004
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Ingår i: 2004 INTERNATIONAL SYMPOSIUM ON SYSTEM-ON-CHIP, PROCEEDINGS. - 0780385586 ; , s. 77-80
-
Konferensbidrag (refereegranskat)abstract
- With fabrication technologies enabling the integration of a billion transistors and allowing gigahertz frequencies, complex systems (System-on-Chip, SoC) can be realized on a single die. The design of such systems provides tremendous challenges to industry and academia. Universities need to invest a huge effort to restructure their related engineering curricula, which is only possible in close co-operations with industry and other Universities. This paper describes a project, co-funded by the European Commission and by industry, where in a joint effort related research results are turned into course contents for SoC-curricula and industry training activities.
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| 6. |
- Yasin, J. N., et al.
(författare)
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Dynamic Formation Reshaping Based on Point Set Registration in a Swarm of Drones
- 2021
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Ingår i: Advances in Intelligent Systems and Computing. - Cham : Springer Nature. ; , s. 577-588
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Konferensbidrag (refereegranskat)abstract
- This work focuses on the formation reshaping in an optimized manner in autonomous swarm of drones. Here, the two main problems are: 1) how to break and reshape the initial formation in an optimal manner, and 2) how to do such reformation while minimizing the overall deviation of the drones and the overall time, i.e. without slowing down. To address the first problem, we introduce a set of routines for the drones/agents to follow while reshaping to a secondary formation shape. And the second problem is resolved by utilizing the temperature function reduction technique, originally used in the point set registration process. The goal is to be able to dynamically reform the shape of multi-agent based swarm in near-optimal manner while going through narrow openings between, for instance obstacles, and then bringing the agents back to their original shape after passing through the narrow passage using point set registration technique.
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| 7. |
- Yasin, J. N., et al.
(författare)
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Low-cost ultrasonic based object detection and collision avoidance method for autonomous robots
- 2021
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Ingår i: International Journal of Information Technology (Singapore). - : Springer Nature. - 2511-2104 .- 2511-2112. ; 13:1, s. 97-107
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Tidskriftsartikel (refereegranskat)abstract
- This work focuses on the development of an effective collision avoidance algorithm that detects and avoids obstacles autonomously in the vicinity of a potential collision by using a single ultrasonic sensor and controlling the movement of the vehicle. The objectives are to minimise the deviation from the vehicle’s original path and also the development of an algorithm utilising one of the cheapest sensors available for very lost cost systems. For instance, in a scenario where the main ranging sensor malfunctions, a backup low cost sensor is required for safe navigation of the vehicle while keeping the deviation to a minimum. The developed algorithm utilises only one ultrasonic sensor and approximates the front shape of the detected object by sweeping the sensor mounted on top of the unmanned vehicle. In this proposed approach, the sensor is rotated for shape approximation and edge detection instead of moving the robot around the encountered obstacle. It has been tested in various indoor situations using different shapes of objects, stationary objects, moving objects, and soft or irregularly shaped objects. The results show that the algorithm provides satisfactory outcomes by entirely avoiding obstacles and rerouting the vehicle with a minimal deviation.
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| 8. |
- Yasin, J N, et al.
(författare)
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Navigation of Autonomous Swarm of Drones Using Translational Coordinates
- 2020
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Ingår i: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - Cham : Springer. ; , s. 353-362
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This work focuses on an autonomous swarm of drones, a multi-agent system, where the leader agent has the capability of intelligent decision making while the other agents in the swarm follow the leader blindly. The proposed algorithm helps with cost cutting especially in the multi-drone systems, i.e., swarms, by reducing the power consumption and processing requirements of each individual agent. It is shown that by applying a pre-specified formation design with feedback cross-referencing between the agents, the swarm as a whole can not only maintain the desired formation and navigate but also avoid collisions with obstacles and other drones. Furthermore, the power consumed by the nodes in the considered test scenario, is reduced by 50% by utilising the proposed methodology.
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| 9. |
- Yi, Chuixiang, et al.
(författare)
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Climate control of terrestrial carbon exchange across biomes and continents
- 2010
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 5:3
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate-carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO2 exchange with the atmosphere across biomes and continents are lacking. Here we present data describing the relationships between net ecosystem exchange of carbon (NEE) and climate factors as measured using the eddy covariance method at 125 unique sites in various ecosystems over six continents with a total of 559 site-years. We find that NEE observed at eddy covariance sites is (1) a strong function of mean annual temperature at mid-and high-latitudes, (2) a strong function of dryness at mid-and low-latitudes, and (3) a function of both temperature and dryness around the mid-latitudinal belt (45 degrees N). The sensitivity of NEE to mean annual temperature breaks down at similar to 16 degrees C (a threshold value of mean annual temperature), above which no further increase of CO2 uptake with temperature was observed and dryness influence overrules temperature influence.
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| 10. |
- Granier, A., et al.
(författare)
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Evidence for soil water control on carbon and water dynamics in European forests during the extremely dry year: 2003
- 2007
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Ingår i: Agricultural and Forest Meteorology. - : Elsevier BV. - 1873-2240 .- 0168-1923. ; 143:1-2, s. 123-145
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Tidskriftsartikel (refereegranskat)abstract
- The drought of 2003 was exceptionally severe in many regions of Europe, both in duration and in intensity. In some areas, especially in Germany and France, it was the strongest drought for the last 50 years, lasting for more than 6 months. We used continuous carbon and water flux measurements at 12 European monitoring sites covering various forest ecosystem types and a large climatic range in order to characterise the consequences of this drought on ecosystems functioning. As soil water content in the root zone was only monitored in a few sites, a daily water balance model was implemented at each stand to estimate the water balance terms: trees and understorey transpiration, rainfall interception, throughfall, drainage in the different soil layers and soil water content. This model calculated the onset date, duration and intensity of the soil water shortage (called water stress) using measured climate and site properties: leaf area index and phenology that both determine tree transpiration and rainfall interception, soil characteristics and root distribution, both influencing water absorption and drainage. At sites where soil water content was measured, we observed a good agreement between measured and modelled soil water content. Our analysis showed a wide spatial distribution of drought stress over Europe, with a maximum intensity within a large band extending from Portugal to NE Germany. Vapour fluxes in all the investigated sites were reduced by drought, due to stomatal closure, when the relative extractable water in soil (REW) dropped below ca. 0.4. Rainfall events during the drought, however, typically induced rapid restoration of vapour fluxes. Similar to the water vapour fluxes, the net ecosystem production decreased with increasing water stress at all the sites. Both gross primary production (GPP) and total ecosystem respiration (TER) also decreased when REW dropped below 0.4 and 0.2, for GPP and TER, respectively. A higher sensitivity to drought was found in the beech, and surprisingly, in the broadleaved Mediterranean forests; the coniferous stands (spruce and pine) appeared to be less drought-sensitive. The effect of drought on tree growth was also large at the three sites where the annual tree growth was measured. Especially in beech, this growth reduction was more pronounced in the year following the drought (2004). Such lag effects on tree growth should be considered an important feature in forest ecosystems, which may enhance vulnerability to more frequent climate extremes.
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| 11. |
- Guang, L., et al.
(författare)
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Coarse and fine-grained monitoring and reconfiguration for energy-efficient NoCs
- 2012
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Ingår i: System on Chip (SoC), 2012 International Symposium on. - : IEEE. - 9781467328951 ; , s. 6376351-
-
Konferensbidrag (refereegranskat)abstract
- Comparative evaluations of centralized, clustered and distributed architectures, for energy management in NoCs, are presented. The paper starts with the systematic examination of the monitoring, decision-making, and reconfiguration processes in building coarse and fine-grained self-adaptation architectures. With examining the physical support in modern technology, network-wide, cluster-wide and per-node energy-management architectures on NoCs are presented, utilizing either voltage regulators or multiple on-chip power delivery networks (MPNs). To identify the effectiveness and efficiency of energy-performance tradeoffs, extensive quantitative simulations are performed with various temporal and spatially changing traffics. Based on the results, we can first observe that the centralized architecture can not adapt to the traffic's spatial locality for effective energy-performance tradeoff. Second, the distributed energy management has the lowest energy-delay product mostly attributed to the fast voltage switching of MPNs, while the synchronization incurs noticeable energy overhead. The clustered architecture, last but not least, is a suitable alternative when the advanced MPN technology is not available. It has low energy and energy-delay product, with very small energy overhead from the monitoring communication.
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| 12. |
- Guang, L., et al.
(författare)
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HLS-DoNoC : High-level simulator for dynamically organizational NoCs
- 2012
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Ingår i: Design and Diagnostics of Electronic Circuits & Systems (DDECS), 2012 IEEE 15th International Symposium on. - : IEEE. - 9781467311854 ; , s. 89-94
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Konferensbidrag (refereegranskat)abstract
- A high-level simulator is presented for the design and analysis of dynamically organizational Networks-on-Chip (DoNoCs). The DoNoC is able to organize statically or dynamically different network nodes for run-time coarse and fine grained reconfiguration, in particular power management. As an important step in the design flow, a simulator for early-stage design exploration is the focus of the paper. Built upon classic wormhole-based NoC architecture, the simulator is capable of experimenting diverse run-time monitoring and reconfiguration methods. In particular, dynamic clusterization can be performed with inter-cluster interfaces properly configured at the run-time. The simulator is flit-level accurate, trace-driven, and easy-to-reconfigure. It supports both synchronous and ratiochronous timing, and can provide the communication performance and power/energy consumption. The paper demonstrates the usage of the simulator in the design of various cluster-based power management schemes.
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| 13. |
- Guang, L., et al.
(författare)
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Survey of self-adaptive NoCs with energy-efficiency and dependability
- 2012
-
Ingår i: International Journal of Embedded and Real-Time Communication Systems. - : IGI Global. - 1947-3176 .- 1947-3184. ; 3:2, s. 1-22
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Forskningsöversikt (refereegranskat)abstract
- The self-adaptive Network-on-Chip (NoC) is a promising communication architecture for massively parallel embedded systems. With constant technology scaling and the consequent stronger influence of process variations, the necessity of run-time monitoring and adaptive reconfiguration becomes widely acknowledged. This article presents a survey of existing techniques and methods, in particular for energy efficiency and dependability. The article firstly examines the motivation of self-adaptive computing in parallel embedded systems. A self-adaptive system model is abstracted, which is composed of goals, monitoring interface, and self-adaptation. Based on the model, the authors extensively survey previous works addressing adaptive NoCs with different monitoring techniques and reconfiguration methods, for power/energy optimization and dependability enhancement. Several design examples are elaborated which serve proper guiding purposes. The authors also identify important issues which are often overlooked or deserve more attention. The article provides review and insight for future design on this topic.
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| 14. |
- Isoaho, J A, et al.
(författare)
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New course on computational platforms towards nanoscale systems
- 2005
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Ingår i: 23rd NORCHIP Conference 2005. - : IEEE. - 1424400643 - 9781424400645 ; , s. 226-229
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Konferensbidrag (refereegranskat)abstract
- In this paper we present an educational approach for a paradigm shift needed when changing from deep submicron CMOS designs to real nano andnanoscaletechnologies [7] in complex communication and computationsystemimplementations. Here we present an introductioncourseimplemented for starting the paradigm shift in curriculum. Here we presentcoursetargets, structure and implementation as well as future designer competence profiles. Thecourseis consisting of five thematic areas: nano-scale technologies, parallelplatforms, concurrent algorithms, reconfigurablesystemsand autonomoussystemmanagement. These thematic areas compound the core of future nanosystems educational program upgrades for current NoC curricula.
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| 15. |
- Jafri, Syed, et al.
(författare)
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Implementation and evaluation of configuration scrubbing on CGRAs : A case study
- 2013
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Ingår i: 2013 International Symposium on System-on-Chip, SoC 2013 - Proceedings. - : IEEE Computer Society. ; , s. 6675262-
-
Konferensbidrag (refereegranskat)abstract
- This paper investigates the overhead imposed by various configuration scrubbing techniques used in fault-tolerant Coarse Grained Reconfigurable Arrays (CGRAs). Today, reconfigurable architectures host large configuration memories. As we progress further in the nanometer regime, these configuration memories have become increasingly susceptible to single event upsets caused e.g. by cosmic radiation. Configuration scrubbing is a frequently used technique to protect these configuration memories against single event upsets. Existing works on configuration scrubbing deal only with FPGA without any reference to the CGRAs (in which configuration memories consume up to 50% of silicon area). Moreover, in the known literature lacks a comprehensive comparison of various configuration scrubbing techniques to guide system designers about the merits/demerits of different scrubbing methods which could be applied to CGRAs. To address these problems, in this paper we classify various configuration scrubbing techniques and quantify their trade-offs when implemented on a CGRA. Synthesis results reveal that scrubbing logic incurs negligible silicon overhead (up to 3% of the area of computational units). Simulation results obtained for a few algorithms/applications (FFT, FIR, matrix multiplication, and WLAN) show that the choice of the configuration scrubbing scheme (external vs. internal) has significant impact on both the size of configuration memory and the number of reconfiguration cycles (respectively 20-80% more and up to 38 times more for the former).
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| 16. |
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| 17. |
- Kelloniemi, A., et al.
(författare)
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The Early-Onset Myocardial Infarction Associated PHACTR1 Gene Regulates Skeletal and Cardiac Alpha-Actin Gene Expression
- 2015
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 10:6
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Tidskriftsartikel (refereegranskat)abstract
- The phosphatase and actin regulator 1 (PHACTR1) locus is a very commonly identified hit in genome-wide association studies investigating coronary artery disease and myocardial infarction (MI). However, the function of PHACTR1 in the heart is still unknown. We characterized the mechanisms regulating Phactr1 expression in the heart, used adenoviral gene delivery to investigate the effects of Phactr1 on cardiac function, and analyzed the relationship between MI associated PHACTR1 allele and cardiac function in human subjects. Phactr1 mRNA and protein levels were markedly reduced (60%, P<0.01 and 90%, P<0.001, respectively) at 1 day after MI in rats. When the direct myocardial effects of Phactr1 were studied, the skeletal a-actin to cardiac a-actin isoform ratio was significantly higher (1.5-fold, P<0.05) at 3 days but 40% lower (P<0.05) at 2 weeks after adenovirus-mediated Phactr1 gene delivery into the anterior wall of the left ventricle. Similarly, the skeletal a-actin to cardiac a-actin ratio was lower at 2 weeks in infarcted hearts overexpressing Phactr1. In cultured neonatal cardiac myocytes, adenovirus-mediated Phactr1 overexpression for 48 hours markedly increased the skeletal a-actin to cardiac a-actin ratio, this being associated with an enhanced DNA binding activity of serum response factor. Phactr1 overexpression exerted no major effects on the expression of other cardiac genes or LV structure and function in normal and infarcted hearts during 2 weeks' follow-up period. In human subjects, MI associated PHACTR1 allele was not associated significantly with cardiac function (n = 1550). Phactr1 seems to regulate the skeletal to cardiac a-actin isoform ratio.
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| 18. |
- Mohamed, S. A. S., et al.
(författare)
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A Survey on Odometry for Autonomous Navigation Systems
- 2019
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers Inc.. - 2169-3536. ; 7, s. 97466-97486
-
Tidskriftsartikel (refereegranskat)abstract
- The development of a navigation system is one of the major challenges in building a fully autonomous platform. Full autonomy requires a dependable navigation capability not only in a perfect situation with clear GPS signals but also in situations, where the GPS is unreliable. Therefore, self-contained odometry systems have attracted much attention recently. This paper provides a general and comprehensive overview of the state of the art in the field of self-contained, i.e., GPS denied odometry systems, and identifies the out-coming challenges that demand further research in future. Self-contained odometry methods are categorized into five main types, i.e., wheel, inertial, laser, radar, and visual, where such categorization is based on the type of the sensor data being used for the odometry. Most of the research in the field is focused on analyzing the sensor data exhaustively or partially to extract the vehicle pose. Different combinations and fusions of sensor data in a tightly/loosely coupled manner and with filtering or optimizing fusion method have been investigated. We analyze the advantages and weaknesses of each approach in terms of different evaluation metrics, such as performance, response time, energy efficiency, and accuracy, which can be a useful guideline for researchers and engineers in the field. In the end, some future research challenges in the field are discussed.
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| 19. |
- Moilanen, A. M., et al.
(författare)
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WDR12, a Member of Nucleolar PeBoW-Complex, Is Up-Regulated in Failing Hearts and Causes Deterioration of Cardiac Function
- 2015
-
Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 10:4
-
Tidskriftsartikel (refereegranskat)abstract
- Aims In a recent genome-wide association study, WD-repeat domain 12 (WDR12) was associated with early-onset myocardial infarction (MI). However, the function of WDR12 in the heart is unknown. We characterized cardiac expression of WDR12, used adenovirus-mediated WDR12 gene delivery to examine effects of WDR12 on left ventricular (LV) remodeling, and analyzed relationship between MI associated WDR12 allele and cardiac function in human subjects. LV WDR12 protein levels were increased in patients with dilated cardiomyopathy and rats post-infarction. In normal adult rat hearts, WDR12 gene delivery into the anterior wall of the LV decreased interventricular septum diastolic and systolic thickness and increased the diastolic and systolic diameters of the LV. Moreover, LV ejection fraction (9.1%, P<0.05) and fractional shortening (12.2%, P<0.05) were declined. The adverse effects of WDR12 gene delivery on cardiac function were associated with decreased cellular proliferation, activation of p38 mitogen-activated protein kinase (MAPK)/heat shock protein (HSP) 27 pathway, and increased protein levels of Block of proliferation 1 (BOP1), essential for ribosome biogenesis. Post-infarction WDR12 gene delivery decreased E/A ratio (32%, P<0.05) suggesting worsening of diastolic function. In human subjects, MI associated WDR12 allele was associated significantly with diastolic dysfunction and left atrial size. WDR12 triggers distinct deterioration of cardiac function in adult rat heart and the MI associated WDR12 variant is associated with diastolic dysfunction in human subjects.
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| 20. |
- Moosavi, S. R., et al.
(författare)
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End-to-end security scheme for mobility enabled healthcare Internet of Things
- 2016
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Ingår i: Future generations computer systems. - : Elsevier. - 0167-739X .- 1872-7115.
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Tidskriftsartikel (refereegranskat)abstract
- We propose an end-to-end security scheme for mobility enabled healthcare Internet of Things (IoT). The proposed scheme consists of (i) a secure and efficient end-user authentication and authorization architecture based on the certificate based DTLS handshake, (ii) secure end-to-end communication based on session resumption, and (iii) robust mobility based on interconnected smart gateways. The smart gateways act as an intermediate processing layer (called fog layer) between IoT devices and sensors (device layer) and cloud services (cloud layer). In our scheme, the fog layer facilitates ubiquitous mobility without requiring any reconfiguration at the device layer. The scheme is demonstrated by simulation and a full hardware/software prototype. Based on our analysis, our scheme has the most extensive set of security features in comparison to related approaches found in literature. Energy-performance evaluation results show that compared to existing approaches, our scheme reduces the communication overhead by 26% and the communication latency between smart gateways and end users by 16%. In addition, our scheme is approximately 97% faster than certificate based and 10% faster than symmetric key based DTLS. Compared to our scheme, certificate based DTLS consumes about 2.2 times more RAM and 2.9 times more ROM resources. On the other hand, the RAM and ROM requirements of our scheme are almost as low as in symmetric key-based DTLS. Analysis of our implementation revealed that the handover latency caused by mobility is low and the handover process does not incur any processing or communication overhead on the sensors.
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| 21. |
- Nigussie, E., et al.
(författare)
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Boosting performance of self-timed delay-insensitive bit parallel on-chip interconnects
- 2011
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Ingår i: IET CIRC DEVICE SYST. - : Institution of Engineering and Technology (IET). - 1751-858X. ; 5:6, s. 505-517
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Tidskriftsartikel (refereegranskat)abstract
- The authors present a performance boosting technique with a better power efficiency for delay-insensitive on-chip interconnects. The increase in signal propagation delay uncertainty with technology scaling makes self-timed delay-insensitive on-chip interconnects the most appropriate alternative. However, achieving high-performance communication in self-timed delay-insensitive links is difficult, especially for large bit parallel transmission because of the time-consuming detection of each bit validity. The authors present a high-speed completion detection technique along with its circuit implementation and two on-chip interconnects which use the proposed completion detection circuit. The performance, power consumption, power efficiency and area of the presented on-chip interconnects are analysed and compared with the conventionally implemented delay-insensitive interconnects. For 64-bit parallel transmission, 2.07 and 1.72 times throughput improvement with 47 and 39% more power efficiency have been achieved for the two interconnects compared to their conventional counterparts. The interconnect circuits are designed and simulated using Cadence Analog Spectre and Hspice with 65 nm complementary metal-oxide semiconductor technology from STMicroelectronics.
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| 22. |
- Nigussie, E., et al.
(författare)
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Semi-Serial On-Chip Link Implementation for Energy Efficiency and High Throughput
- 2012
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Ingår i: IEEE Transactions on Very Large Scale Integration (vlsi) Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1063-8210 .- 1557-9999. ; 20:12, s. 2265-2277
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Tidskriftsartikel (refereegranskat)abstract
- A high-throughput and low-energy semi-serial on-chip communication link based on novel design techniques and circuit solutions is presented. This self-timed link is designed using high-speed serialization/deserializtion and pulse dual-rail encoding techniques. The link also employs wave-pipelined differential pulse current-mode signaling to maintain the high speed data intake from the serializer. The energy efficiency of the proposed semi-serial link, which consists of bit-serial links in parallel, mainly comes from the sharing of the novel serializer's control circuit among the bit-serial links. In addition, the integration of pulse signaling with wave-pipelining, the use of a new low-complexity data validity detection technique, and the avoidance of data decoding logic also contribute to the power reduction. Furthermore, the formulated pulse dual-rail encoding provides an opportunity to implement pulse signaling at no cost. The ability to detect data validity at bit level allows acknowledgment per word without losing the delay-insensitivity of the transmission. The proposed semi-serial link is analyzed and compared with bit-serial and fully bit-parallel links for 64-bit data and communication distances of 1 to 8 mm. The semi-serial link which consists of eight bit-serial links provides 72.72 Gbps throughput with 286 fJ/bit energy dissipation for 8 mm transmission. It dissipates the lowest energy per bit compared to fully bit-parallel links while achieving the same throughput. The links are designed and simulated in Cadence Analog Spectre using 65-nm technology from STMicroelectronics.
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| 23. |
- Satti, J. A., et al.
(författare)
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Highly-dense flexible chipless RFID tag
- 2017
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Ingår i: IEICE Electronics Express. - : IEEE. - 1349-2543. ; 14:18
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Tidskriftsartikel (refereegranskat)abstract
- A 27-bit circular shaped, highly-dense, fully printable chipless radio frequency identification (RFID) tag is presented in this letter. High data capacity is provided in a compact size. The total dimension of the tag is 22 × 22mm2. For exciting the tag, the linearly polarized incident plane wave is used. The circular shaped tag structure is analyzed for three different substrates, i.e., Rogers RT/duroid®/5870, Taconic TLX-0 and DuPont™ Kapton® HN. The spectral range for Rogers RT/duroid®/5870 is 3.3-13.5 GHz, 3.4-13.6 GHz for Taconic TLX-0 and 3.7-15.1 GHz for DuPont™ Kapton® HN substrate. Flexibility is achieved by using Kapton® HN substrate. The presented tag is low-cost and flexible; hence it can be easily deployed on wide range of objects.
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| 24. |
- Tirkkonen, J., et al.
(författare)
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Cardiac arrest teams and medical emergency teams in Finland : a nationwide cross- sectional postal survey
- 2014
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 58:4, s. 420-427
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe implementation, characteristics and utilisation of cardiac arrest teams (CATs) and medical emergency teams (METs) in Finland are unknown. We aimed to evaluate how guidelines on advanced in-hospital resuscitation have been translated to practice. MethodsA cross-sectional postal survey including all public hospitals providing anaesthetic services. ResultsOf the 55 hospitals, 51 (93%) participated in the study. All hospitals with intensive care units (university and central hospitals, n=24) took part. In total, 88% of these hospitals (21/24) and 30% (8/27) of the small hospitals had CATs. Most hospitals with CATs (24/29) recorded team activations. A structured debriefing after a resuscitation attempt was organised in only one hospital. The median incidence of in-hospital cardiac arrest in Finland was 1.48 (Q(1)=0.93, Q(3)=1.93) per 1000 hospital admissions. METs had been implemented in 31% (16/51) of the hospitals. A physician participated in MET activation automatically in half (8/16) of the teams. Operating theatres (13/16), emergency departments (10/16) and paediatric wards (7/16) were the most common sites excluded from the METs' operational areas. The activation thresholds for vital signs varied between hospitals. The lower upper activation threshold for respiratory rate was associated with a higher MET activation rate. The national median MET activation rate was 2.3 (1.5, 4.8) per 1000 hospital admissions and 1.5 (0.96, 4.0) per every cardiac arrest. ConclusionsCurrent guidelines emphasise the preventative actions on in-hospital cardiac arrest. Practices are changing accordingly but are still suboptimal especially in central and district hospitals. Unified guidelines on rapid response systems are required.
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- Tirkkonen, J., et al.
(författare)
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Vital dysfunctions after intensive care discharge : prevalence and impact on patient outcome
- 2013
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 57:1, s. 56-62
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Tidskriftsartikel (refereegranskat)abstract
- Background Patients discharged from the intensive care unit (ICU) are at increased risk for serious adverse events (SAEs). Recording vital functions and comprehending the consequences of altered vitals on general wards may be suboptimal. This potentially endangers recovery after successful intensive care. We aimed to determine the prevalence of vital dysfunctions after ICU discharge and their effect on patient outcome. Methods A prospective observational study. Adult patients discharged from a tertiary referral hospital ICU to general wards without treatment limitations were visited 24?h afterwards; their vitals were measured and reported to ward staff. Attending ward nurse responsible for patient was interviewed. Results The cohort consisted of 184 patients who had survived the first 24?h on the ward without complications (age: 57 +/- 16 years; male: 68%). The prevalence of objectively measured vital dysfunctions was 15%, and the attending nurse had been unusually concerned about the patient in 19% of cases. Of the 184 patients, 9.8% subsequently suffered an SAE. In a multivariate logistic regression model, only vital dysfunctions (odds ratio 3.79; 95% confidence interval 1.18-12.2) and nurse concern (3.63; 1.17-11.3) were independently associated with an increased incidence of SAE. Medical emergency team (MET) assistance was never considered necessary by ward staff. Sensitivity of observed altered vitals on SAEs was 50% and specificity 89%. Sensitivity of nurse concern was 26%, specificity 84%. Conclusions Simple vital function measurement and attending ward nurse's subjective assessment facilitate early detection of post-ICU patients at risk. The threshold in seeking assistance through MET remains high.
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