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Publications (10 of 24) Show all publications
Rahmani, M., Koutsopoulos, H. N. & Jenelius, E. (2017). Travel time estimation from sparse floating car data with consistent path inference: A fixed point approach. Transportation Research Part C: Emerging Technologies, 85, 628-643.
Open this publication in new window or tab >>Travel time estimation from sparse floating car data with consistent path inference: A fixed point approach
2017 (English)In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 85, 628-643 p.Article in journal (Refereed) Published
Abstract [en]

Estimation of urban network link travel times from sparse floating car data (FCD) usually needs pre-processing, mainly map-matching and path inference for finding the most likely vehicle paths that are consistent with reported locations. Path inference requires a priori assumptions about link travel times; using unrealistic initial link travel times can bias the travel time estimation and subsequent identification of shortest paths. Thus, the combination of path inference and travel time estimation is a joint problem. This paper investigates the sensitivity of estimated travel times, and proposes a fixed point formulation of the simultaneous path inference and travel time estimation problem. The methodology is applied in a case study to estimate travel times from taxi FCD in Stockholm, Sweden. The results show that standard fixed point iterations converge quickly to a solution where input and output travel times are consistent. The solution is robust under different initial travel times assumptions and data sizes. Validation against actual path travel time measurements from the Google API and an instrumented vehicle deployed for this purpose shows that the fixed point algorithm improves shortest path finding. The results highlight the importance of the joint solution of the path inference and travel time estimation problem, in particular for accurate path finding and route optimization.

Place, publisher, year, edition, pages
Elsevier, 2017
Keyword
Fixed point problem, Floating car data, Path inference, Travel time estimation
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:kth:diva-218115 (URN)10.1016/j.trc.2017.10.012 (DOI)2-s2.0-85033608912 (Scopus ID)
Note

QC 20171124

Available from: 2017-11-24 Created: 2017-11-24 Last updated: 2017-11-24Bibliographically approved
Haghbayan, M.-H., Rahmani, A.-M., Miele, A., Fattah, M., Plosila, J., Liljeberg, P. & Tenhunen, H. (2016). A Power-Aware Approach for Online Test Scheduling in Many-Core Architectures. I.E.E.E. transactions on computers (Print), 65(3), 730-743.
Open this publication in new window or tab >>A Power-Aware Approach for Online Test Scheduling in Many-Core Architectures
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2016 (English)In: I.E.E.E. transactions on computers (Print), ISSN 0018-9340, E-ISSN 1557-9956, Vol. 65, no 3, 730-743 p.Article in journal (Refereed) Published
Abstract [en]

Aggressive technology scaling triggers novel challenges to the design of multi-/many-core systems, such as limited power budget and increased reliability issues. Today's many-core systems employ dynamic power management and runtime mapping strategies trying to offer optimal performance while fulfilling power constraints. On the other hand, due to the reliability challenges, online testing techniques are becoming a necessity in current and near future technologies. However, state-of-the-art techniques are not aware of the other power/performance requirements. This paper proposes a power-aware non-intrusive online testing approach for many-core systems. The approach schedules software based self-test routines on the various cores during their idle periods, while honoring the power budget and limiting delays in the workload execution. A test criticality metric, based on a device aging model, is used to select cores to be tested at a time. Moreover, power and reliability issues related to the testing at different voltage and frequency levels are also handled. Extensive experimental results reveal that the proposed approach can i) efficiently test the cores within the available power budget causing a negligible performance penalty, ii) adapt the test frequency to the current cores' aging status, and iii) cover available voltage and frequency levels during the testing.

Place, publisher, year, edition, pages
IEEE, 2016
Keyword
Online testing, functional testing, dark silicon, power capping, many-core systems, aging, lifetime reliability
National Category
Computer Sciences
Identifiers
urn:nbn:se:kth:diva-184025 (URN)10.1109/TC.2015.2481411 (DOI)000370729600006 ()2-s2.0-84962052856 (Scopus ID)
Note

QC 20160324

Available from: 2016-03-24 Created: 2016-03-22 Last updated: 2018-01-10Bibliographically approved
Anzanpour, A., Rahmani, A.-M., Liljeberg, P. & Tenhunen, H. (2016). Context-aware early warning system for in-home healthcare using internet-of-things. In: 2nd International Summit on Internet of Things, IoT 360° 2015: . Paper presented at 27 October 2015 through 29 October 2015 (pp. 517-522). Springer.
Open this publication in new window or tab >>Context-aware early warning system for in-home healthcare using internet-of-things
2016 (English)In: 2nd International Summit on Internet of Things, IoT 360° 2015, Springer, 2016, 517-522 p.Conference paper, Published paper (Refereed)
Abstract [en]

Early warning score (EWS) is a prediction method to notify caregivers at a hospital about the deterioration of a patient. Deterioration can be identified by detecting abnormalities in patient’s vital signs several hours prior the condition of the patient gets life-threatening. In the existing EWS systems, monitoring of patient’s vital signs and the determining the score is mostly performed in a paper and pen based way. Furthermore, currently it is done solely in a hospital environment. In this paper, we propose to import this system to patients’ home to provide an automated platform which not only monitors patents’ vital signs but also looks over his/her activities and the surrounding environment. Thanks to the Internet-of-Things technology, we present an intelligent early warning method to remotely monitor in-home patients and generate alerts in case of different medical emergencies or radical changes in condition of the patient. We also demonstrate an early warning score analysis system which continuously performs sensing, transferring, and recording vital signs, activity-related data, and environmental parameters.

Place, publisher, year, edition, pages
Springer, 2016
Keyword
E-Health, Early warning score, Internet-of-things, Remote patient monitoring, Deterioration, Hospitals, Patient monitoring, E health, Early Warning System, Early-warning method, Environmental parameter, Hospital environment, Internet of things technologies, Surrounding environment, Internet of things
National Category
Computer Systems
Identifiers
urn:nbn:se:kth:diva-201996 (URN)10.1007/978-3-319-47063-4_56 (DOI)000398616500056 ()2-s2.0-85000814878 (Scopus ID)9783319470627 (ISBN)
Conference
27 October 2015 through 29 October 2015
Note

QC 20170224

Available from: 2017-02-24 Created: 2017-02-24 Last updated: 2017-04-28Bibliographically approved
Odunmbaku, A., Rahmani, A.-M., Liljeberg, P. & Tenhunen, H. (2016). Elderly monitoring system with sleep and fall detector. In: 2nd International Summit on Internet of Things, IoT 360° 2015: . Paper presented at 27 October 2015 through 29 October 2015 (pp. 473-480). Springer.
Open this publication in new window or tab >>Elderly monitoring system with sleep and fall detector
2016 (English)In: 2nd International Summit on Internet of Things, IoT 360° 2015, Springer, 2016, 473-480 p.Conference paper, Published paper (Refereed)
Abstract [en]

Monitoring of elderly people has drawn attention of healthcare and medical professionals. Various health problems have been attributed to either fall or lack of sleep in the context of elderly people. Falling and sleep problems on a long term basis could eventually lead to sharp deteriorate in health, poor state of health and high cost for covering their health care. In this paper a new accurate and convenient while cost-efficient implementation of a monitoring system is presented. The use of an accelerometer based system was utilized in this work. The targeted device fit for this implementation is a smart watch. The algorithm of both the fall detector and sleep monitor presented in this work have been implemented and tested on multiple subjects. It also includes a database backend which is used to save the information collected from the system for further analysis and can provide healthcare professional with more insight of the person’s life and can help more on further health medication being given to the person.

Place, publisher, year, edition, pages
Springer, 2016
Keyword
Fall detector, Healthcare, Internet-of-things, Sleep monitor, Health care, Internet of things, Sleep research, Elderly monitoring, Elderly people, Fall detectors, Health care professionals, Medical professionals, Monitoring system, Sleep problems, State of health, Monitoring
National Category
Medical Engineering
Identifiers
urn:nbn:se:kth:diva-201993 (URN)10.1007/978-3-319-47063-4_51 (DOI)000398616500051 ()2-s2.0-85000819174 (Scopus ID)9783319470627 (ISBN)
Conference
27 October 2015 through 29 October 2015
Note

QC 20170303

Available from: 2017-03-03 Created: 2017-03-03 Last updated: 2017-04-28Bibliographically approved
Rahmani, A.-M., Haghbayan, M.-H., Kanduri, A., Yemane Weldezion, A., Liljeberg, P., Plosila, J., . . . Tenhunen, H. (2015). Dynamic Power Management for Many-Core Platforms in the Dark Silicon Era: A Multi-Objective Control Approach. In: Low Power Electronics and Design (ISLPED), 2015 IEEE/ACM International Symposium on: . Paper presented at IEEE/ACM International Symposium on Low Power Electronics and Design (ISLPED’15),22-24 July 2015 Rome, Italy (pp. 219-224). IEEE conference proceedings.
Open this publication in new window or tab >>Dynamic Power Management for Many-Core Platforms in the Dark Silicon Era: A Multi-Objective Control Approach
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2015 (English)In: Low Power Electronics and Design (ISLPED), 2015 IEEE/ACM International Symposium on, IEEE conference proceedings, 2015, 219-224 p.Conference paper, Published paper (Refereed)
Abstract [en]

Power management of NoC-based many-core systems with runtime application mapping becomes more challenging in the dark silicon era. It necessitates a multi-objective control approach to consider an upper limit on total power consumption, dynamic behaviour of workloads, processing elements utilization, per-core power consumption, and load on network-on-chip. In this paper, we propose a multi-objective dynamic power management method that simultaneously considers all of these parameters. Fine-grained voltage and frequency scaling, including near-threshold operation, and per-core power gating are utilized to optimize the performance. In addition, a disturbance rejecter is designed that proactively scales down activity in running applications when a new application commences execution, to prevent sharp power budget violations. Simulations of dynamic workloads and mixed time-critical application profiles show that our method is effective in honoring the power budget while considerably boosting the system throughput and reducing power budget violation, compared to the state-of-the-art power management policies.

Place, publisher, year, edition, pages
IEEE conference proceedings, 2015
National Category
Embedded Systems Control Engineering Computer Systems
Identifiers
urn:nbn:se:kth:diva-168992 (URN)10.1109/ISLPED.2015.7273517 (DOI)000380442300037 ()2-s2.0-84958547396 (Scopus ID)978-1-4673-8008-9 (ISBN)
External cooperation:
Conference
IEEE/ACM International Symposium on Low Power Electronics and Design (ISLPED’15),22-24 July 2015 Rome, Italy
Note

QC 20151218

Available from: 2015-06-10 Created: 2015-06-10 Last updated: 2016-09-05Bibliographically approved
Nguyen Gia, T., Jiang, M., Rahmani, A.-M., Westerlund, T., Mankodiya, K., Liljeberg, P. & Tenhunen, H. (2015). Fog Computing in Body Sensor Networks: An Energy Efficient Approach. In: : . Paper presented at IEEE International Body Sensor Networks Conference (BSN’15),June 9 - 12, 2015, Cambridge, USA. .
Open this publication in new window or tab >>Fog Computing in Body Sensor Networks: An Energy Efficient Approach
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2015 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Internet of Things based systems provides a viable and organized approach to improve health and wellbeing of mankind. Particularly, health monitoring systems based on wireless body sensor networks become attainable due to increasing number of elderly people that needs healthcare services frequently. In such system, power consumption of a sensor node is an important issue. In order to handle the issue, a smart gateway with fog computing capabilities is presented. Fog computing includes several services such as distributed database management, Electrocardiography (ECG) feature extraction, user graphical interface with access management and push notations. With fog computing, the burden of a cloud server can be reduced and more than 50% of power consumption can be saved at a sensor node. Additionally, through fog computing, the system ensures that the obtained health data can be visualized and diagnosed in real-time even though there is a disconnection between the gateway and cloud server.

National Category
Computer Systems Communication Systems Embedded Systems Other Industrial Biotechnology
Identifiers
urn:nbn:se:kth:diva-168994 (URN)
Conference
IEEE International Body Sensor Networks Conference (BSN’15),June 9 - 12, 2015, Cambridge, USA
Note

QC 20150623

Available from: 2015-06-10 Created: 2015-06-10 Last updated: 2015-09-17Bibliographically approved
Negash, B., Rahmani, A.-M., Westerlund, T., Liljeberg, P. & Tenhunen, H. (2015). LISA: Lightweight Internet of Things Service Bus Architecture. Paper presented at The 6th International Conference on Ambient Systems, Networks and Technologies (ANT-2015), the 5th International Conference on Sustainable Energy Information Technology (SEIT-2015). Procedia Computer Science, 52, 436-443.
Open this publication in new window or tab >>LISA: Lightweight Internet of Things Service Bus Architecture
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2015 (English)In: Procedia Computer Science, ISSN 1877-0509, E-ISSN 1877-0509, Vol. 52, 436-443 p.Article in journal (Refereed) Published
Abstract [en]

A critical challenge faced in Internet of Things (IoT) is the heterogeneous nature of its nodes from the network protocol and platform point of view. To tackle the heterogeneous nature, we introduce a distributed and lightweight service bus, LISA, which fits into network stack of a real-time operating system for constrained nodes in IoT. LISA provides an application programming interface for developers of IoT on tiny devices. It hides platform and protocol variations underneath it, thus facilitating interoperability challenges in IoT implementations. LISA is inspired by the Network on Terminal Architecture (NoTA), a service centric open architecture by Nokia Research Center. Unlike many other interoperability frameworks, LISA is designed specifically for resource constrained nodes and it provides essential features of a service bus for easy service oriented architecture implementation.

Place, publisher, year, edition, pages
Elsevier, 2015
Keyword
NoTA, LISA, Interoperability, IoT, ESB, SOA, 6LoWPAN, RIOT
National Category
Embedded Systems Communication Systems Computer Systems
Identifiers
urn:nbn:se:kth:diva-168960 (URN)10.1016/j.procs.2015.05.010 (DOI)000361567100053 ()2-s2.0-84939135477 (Scopus ID)
Conference
The 6th International Conference on Ambient Systems, Networks and Technologies (ANT-2015), the 5th International Conference on Sustainable Energy Information Technology (SEIT-2015)
Note

QC 20150618

Available from: 2015-06-09 Created: 2015-06-09 Last updated: 2017-12-04Bibliographically approved
Haghbayan, M.-H., Kanduri, A., Rahmani, A.-M., Liljeberg, P., Jantsch, A. & Tenhunen, H. (2015). MapPro: Proactive Runtime Mapping for Dynamic Workloads by Quantifying Ripple Effect of Applications on Networks-on-Chip. In: NOCS '15 Proceedings of the 9th International Symposium on Networks-on-Chip: . Paper presented at IEEE/ACM International Symposium on Networks-on-Chip (NOCS),September 28-30 2015, Vancouver, Canada. ACM Digital Library.
Open this publication in new window or tab >>MapPro: Proactive Runtime Mapping for Dynamic Workloads by Quantifying Ripple Effect of Applications on Networks-on-Chip
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2015 (English)In: NOCS '15 Proceedings of the 9th International Symposium on Networks-on-Chip, ACM Digital Library, 2015Conference paper, Published paper (Refereed)
Abstract [en]

Increasing dynamic workloads running on NoC-based many-core systems necessitates efficient runtime mapping strategies. With an unpredictable nature of application profiles, selecting a rational region to map an incoming application is an NP-hard problem in view of minimizing congestion and maximizing performance. In this paper, we propose a proactive region selection strategy which prioritizes nodes that offer lower congestion and dispersion. Our proposed strategy, MapPro, quantitatively represents the propagated impact of spatial availability and dispersion on the network with every new mapped application. This allows us to identify a suitable region to accommodate an incoming application that results in minimal congestion and dispersion. We cluster the network into squares of different radii to suit applications of different sizes and proactively select a suitable square for a new application, eliminating the overhead caused with typical reactive mapping approaches. We evaluated our proposed strategy over different traffic patterns and observed gains of up to 41% in energy efficiency, 28% in congestion and 21% dispersion when compared to the state-of-the-art region selection methods.

Place, publisher, year, edition, pages
ACM Digital Library, 2015
National Category
Computer Systems Embedded Systems
Identifiers
urn:nbn:se:kth:diva-169509 (URN)
Conference
IEEE/ACM International Symposium on Networks-on-Chip (NOCS),September 28-30 2015, Vancouver, Canada
Note

QC 20160212

Available from: 2015-06-15 Created: 2015-06-15 Last updated: 2016-02-12Bibliographically approved
Rahmani, M., Jenelius, E. & Koutsopoulos, H. (2015). Non-parametric estimation of route travel time distributions from low-frequency floating car data. Transportation Research Part C: Emerging Technologies, 58B, 343-362.
Open this publication in new window or tab >>Non-parametric estimation of route travel time distributions from low-frequency floating car data
2015 (English)In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 58B, 343-362 p.Article in journal (Refereed) Published
Abstract [en]

The paper develops a non-parametric method for route travel time distribution estimation using low-frequency floating car data (FCD). While most previous work has focused on link travel time estimation, the method uses FCD observations for estimating the travel time distribution on a route. Potential biases associated with the use of sparse FCD are identified. The method involves a number of steps to reduce the impact of these biases. For evaluation purposes, a case study is used to estimate route travel times from taxi FCD in Stockholm, Sweden. Estimates are compared to observed travel times for routes equipped with Automatic Number Plate Recognition (ANPR) cameras with promising results. As vehicles collecting FCD (in this case, taxis) may not be a representative sample of the overall vehicle fleet and driver population, the ANPR data along several routes are also used to assess and correct for this bias. The method is computationally efficient, scalable, and supports real time applications with large data sets through a proposed distributed implementation.

Place, publisher, year, edition, pages
Elsevier, 2015
Keyword
Floating car data, Automatic number plate recognition, Kernel estimation, Route travel time distribution, Sampling bias, Non-parametric
National Category
Transport Systems and Logistics
Research subject
Transport Science
Identifiers
urn:nbn:se:kth:diva-167648 (URN)10.1016/j.trc.2015.01.015 (DOI)000361923400014 ()2-s2.0-84940462344 (Scopus ID)
Note

QC 20170201

Available from: 2015-05-22 Created: 2015-05-22 Last updated: 2017-12-04Bibliographically approved
Rahimi Moosavi, S., Nguyen Gia, T., Rahmani, A.-M., Nigussie, E., Virtanen, S., Isoaho, J. & Tenhunen, H. (2015). SEA: A Secure and Efficient Authentication and Authorization Architecture for IoT-Based Healthcare Using Smart Gateways. Paper presented at The 6th International Conference on Ambient Systems, Networks and Technologies (ANT-2015), the 5th International Conference on Sustainable Energy Information Technology (SEIT-2015). Procedia Computer Science, 52, 452-459.
Open this publication in new window or tab >>SEA: A Secure and Efficient Authentication and Authorization Architecture for IoT-Based Healthcare Using Smart Gateways
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2015 (English)In: Procedia Computer Science, ISSN 1877-0509, E-ISSN 1877-0509, Vol. 52, 452-459 p.Article in journal (Refereed) Published
Abstract [en]

In this paper, a secure and efficient authentication and authorization architecture for IoT-based healthcare is developed. Security and privacy of patients’ medical data are crucial for the acceptance and ubiquitous use of IoT in healthcare. Secure authentication and authorization of a remote healthcare professional is the main focus of this work. Due to resource constraints of medical sensors, it is infeasible to utilize conventional cryptography in IoT-based healthcare. In addition, gateways in existing IoTs focus only on trivial tasks without alleviating the authentication and authorization challenges. In the presented architecture, authentication and authorization of a remote end-user is done by distributed smart e-health gateways to unburden the medical sensors from performing these tasks. The proposed architecture relies on the certificate-based DTLS handshake protocol as it is the main IP security solution for IoT. The proposed authentication and authorization architecture is tested by developing a prototype IoT-based healthcare system. The prototype is built of a Pandaboard, a TI SmartRF06 board and WiSMotes. The CC2538 module integrated into the TI board acts as a smart gateway and the WisMotes act as medical sensor nodes. The proposed architecture is more secure than a state-of-the-art centralized delegation-based architecture because it uses a more secure key management scheme between sensor nodes and the smart gateway. Furthermore, the impact of DoS attacks is reduced due to the distributed nature of the architecture. Our performance evaluation results show that compared to the delegation-based architecture, the proposed architecture reduces communication overhead by 26% and communication latency from the smart gateway to the end-user by 16%.

Place, publisher, year, edition, pages
Elsevier, 2015
Keyword
Internet of Things, Healthcare, Smart Home/Hospital, Smart Gateway, Security, Authentication, Authorization
National Category
Embedded Systems Computer Systems Communication Systems
Identifiers
urn:nbn:se:kth:diva-168664 (URN)10.1016/j.procs.2015.05.013 (DOI)000361567100055 ()2-s2.0-84939148509 (Scopus ID)
Conference
The 6th International Conference on Ambient Systems, Networks and Technologies (ANT-2015), the 5th International Conference on Sustainable Energy Information Technology (SEIT-2015)
Note

QC 20150618

Available from: 2015-06-07 Created: 2015-06-07 Last updated: 2017-12-04Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8750-8242

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