@proceedings{391,

title = {Fluidity: Providing flexible deployment and adaptation policy experimentation for serverless and distributed applications spanning cloud–edge–mobile environments},

author = {Foivos Pournaropoulos and Alexandros Patras and Christos D. Antonopoulos and Nikolaos Bellas and Spyros Lalis},

doi = {10.1016/j.future.2024.03.031},

year  = {2024},

date = {2024-08-01},

journal = {Future Generation Computer Systems},

volume = {157},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{392,

title = {Flexible and Efficient Deployment of Data Processing Pipelines on Wireless IoT Systems},

author = {Giorgos Polychronis},

doi = {10.1109/sas60918.2024.10636514},

year  = {2024},

date = {2024-07-01},

journal = {2024 IEEE Sensors Applications Symposium (SAS)},

pages = {1-6},

publisher = {IEEE},

abstract = {There is an increasing number of IoT devices that 

do not merely act as sensor nodes but are also sufficiently 

powerful to perform some local data processing before data is 

sent upstream to more powerful servers or the cloud. In this 

paper, we present a framework for the flexible deployment and 

execution of sensing and data processing application components 

on embedded, industrial-strength nodes that can be connected to 

a wide variety of sensors. This is done using textual, declarative 

descriptions instead of actual code, in conjunction with a pub/sub 

approach for data exchange between such components. As a 

result, it becomes possible to build and deploy in-network 

data processing pipelines in efficient way, even on top of lowbandwidth wireless links. Our evaluation shows that the proposed 

approach can reduce the size of application logic by 95.3% 

and the deployment time by up to 91.1% compared to a more 

conventional deployment of binaries. Also, the ability to process 

data near or even directly on the nodes that are connected to the 

sensors proving the raw measurements, can reduce the number 

of messages by 97.7% and improve message latency by up to 

44.3% vs sending all data and processing it on a server},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{394,

title = {Accelerating Machine Learning Inference on GPUs with SYCL},

author = {Ioanna-Maria Panagou and Nikolaos Bellas and Lorenzo Moneta and Sanjiban Sengupta},

doi = {10.1145/3648115.3648123},

year  = {2024},

date = {2024-04-01},

journal = {Proceedings of the 12th International Workshop on OpenCL and SYCL},

pages = {1-2},

publisher = {ACM},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{393,

title = {Should I Stay or Should I Go: A Learning Approach for Drone-based Sensing Applications},

author = {Giorgos Polychronis and Manos Koutsoubelias and Spyros Lalis},

doi = {10.1109/dcoss-iot61029.2024.00058},

year  = {2024},

date = {2024-04-01},

journal = {2024 20th International Conference on Distributed Computing in Smart Systems and the Internet of Things (DCOSS-IoT)},

pages = {339-346},

publisher = {IEEE},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{390,

title = {Supporting the Adaptive Deployment of Modular Applications in Cloud-Edge-Mobile Systems},

author = {Foivos Pournaropoulos and Christos D. Antonopoulos and Spyros Lalis},

doi = {10.5555/3639940.3639966},

year  = {2023},

date = {2023-09-01},

journal = {International Conference on Embedded Wireless Systems and Networks (EWSN)},

address = {Rende, Italy},

abstract = {We introduce Fluidity, a framework enabling the flexible 

and adaptive deployment of modular applications in systems 

comprising cloud, edge, and mobile IoT nodes. Based on 

a declarative description of application requirements, Fluidity plans and executes an initial deployment of application 

components in the cloud-edge-mobile continuum. At runtime, Fluidity monitors resource availability and the position 

of mobile nodes, and adapts the deployment of the application accordingly, without any intervention from the application owner or system administrator. Notably, Fluidity allows 

applications to provide their own deployment and adaptation 

policies and to switch between different policies at runtime, 

while the application is running. We discuss the design and 

implementation of Fluidity in detail and provide an evaluation using a lab testbed, where the mobile node is a simulated 

drone. Our results show that the core mechanisms of Fluidity 

can adapt the application at reasonable overhead.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{387,

title = {Flexible Computation Offloading at the Edge for Autonomous Drones with Uncertain Flight Times},

author = {Giorgos Polychronis and Spyros Lalis},

year  = {2023},

date = {2023-06-01},

journal = {International Conference on Distributed Computing in Smart Systems and the Internet of Things (DCOSS-IoT)},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{386,

title = {Joint Edge Resource Allocation and Path Planning for Drones with Energy Constraints},

author = {Giorgos Polychronis and Spyros Lalis},

year  = {2022},

date = {2022-11-01},

journal = {International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services (Mobiquitous)},

pages = {11},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{383,

title = {FPGA Roofline modeling and its Application to Visual SLAM},

author = {Ioanna-Maria Panagou and Maria Rafaela Gkeka and Alexandros Patras and Spyros Lalis and Christos D. Antonopoulos and Nikolaos Bellas},

year  = {2022},

date = {2022-08-01},

journal = {International Conference on Field Programmable Logic and Applications (FPL)},

address = {Belfast, United Kingdom},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{382,

title = {Planning Computation Offloading on Shared Edge Infrastructure for Multiple Drones},

author = {Giorgos Polychronis and Spyros Lalis},

year  = {2022},

date = {2022-07-01},

journal = {15th IEEE International Workshop on Wireless Sensor, Robot and UAV Networks (WiSARN)},

address = {Bologna, Italy},

abstract = {This work presents an offline heuristic for the fair allocation of shared edge server resources to support computation offloading for drones so as to evenly reduce the respective mission times.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{381,

title = {Fractus: Orchestration of Distributed Applications in the Drone-Edge-Cloud Continuum},

author = {Nasos Grigoropoulos and Spyros Lalis},

year  = {2022},

date = {2022-06-01},

journal = {Proc. 46th IEEE Annual Computers, Software and Applications Conference (COMPSAC 2022)},

address = {Virtual Conference},

abstract = {This work presents an orchestration framework for the automated deployment of component-based applications in the drone-edge-cloud continuum, which provides users with abstractions for describing the application’s placement and communication requirements, allocates resources in a mission-aware fashion by considering the drone operation area, establishes and maintains connectivity between components by transparently leveraging different networking capabilities, and tackles safety and privacy issues via policy-based access to mobility and sensor resources.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{377,

title = {Dynamic Management of CPU Resources Towards Energy Efficient and Profitable Datacentre Operation},

author = {Christos Kalogirou and Christos D. Antonopoulos and Spyros Lalis and Nikolaos Bellas},

year  = {2022},

date = {2022-06-01},

journal = {25th Workshop on Job Scheduling Strategies for Parallel Processing (JSSPP 2022)},

address = {Virtual Conference},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{376,

title = {FPGA Accelerators for Robust Visual SLAM on Humanoid Robots},

author = {Maria Rafaela Gkeka and Alexandros Patras and Nikolaos Tavoularis and Stylianos Piperakis and Emmanouil Hourdakis and Panos Trahanias and Christos D. Antonopoulos and Spyros Lalis and Nikolaos Bellas},

year  = {2022},

date = {2022-02-01},

journal = {International Symposium on Field-Programmable Gate Arrays (FPGA)},

address = {Virtual Conference},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{375,

title = {System Architecture for Autonomous Drone-based Remote Sensing},

author = {Manos Koutsoubelias and Nasos Grigoropoulos and Giorgos Polychronis and Giannis Badakis and Spyros Lalis},

year  = {2021},

date = {2021-11-01},

journal = {International Conference on Mobile and Ubiquitous Systems: Computing, Networking and Services (Mobiquitous)},

pages = {11},

address = {Virtual Conference},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{374,

title = {Architectures for SLAM and Augmented Reality Computing},

author = {Nikolaos Bellas and Christos D. Antonopoulos and Spyros Lalis and Maria Rafaela Gkeka and Alexandros Patras and Georgios Keramidas and Iakovos Stamoulis and Nikolaos Tavoularis and Stylianos Piperakis and Emmanouil Hourdakis and Panos Trahanias and Paul Zikas and George Papagiannakis and Ioanna Kartsonaki},

year  = {2021},

date = {2021-09-01},

journal = {International Conference on Field-Programmable Logic and Applications (FPL)},

address = {Virtual Conference},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{373,

title = {Safe Optimistic Path Planning for Autonomous Drones under Dynamic Energy Costs},

author = {Giorgos Polychronis and Spyros Lalis},

year  = {2021},

date = {2021-09-01},

journal = {IEEE International Conference on Intelligent Transportation (ITSC)},

address = {Indianapolis, United States},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{372,

title = {Robust Precision Landing for Autonomous Drones Combining Vision-based and Infrared Sensors},

author = {Giannis Badakis and Manos Koutsoubelias and Spyros Lalis},

year  = {2021},

date = {2021-08-01},

journal = {IEEE Sensors Applications Symposium (SAS)},

address = {Virtual Conference},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{379,

title = {Fractus: Orchestration of Distributed Applications in the Drone-Edge-Cloud Continuum},

author = {Nasos Grigoropoulos and Spyros Lalis},

year  = {2021},

date = {2021-06-01},

journal = {Proc. 46th IEEE Annual Computers, Software and Applications Conference (COMPSAC 2022)},

address = {Virtual Conference},

abstract = {This work presents an orchestration framework for the automated deployment of component-based applications in the drone-edge-cloud continuum, which provides users with abstractions for describing the application’s placement and communication requirements, allocates resources in a mission-aware fashion by considering the drone operation area, establishes and maintains connectivity between components by transparently leveraging different networking capabilities, and tackles safety and privacy issues via policy-based access to mobility and sensor resources.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{370,

title = {Exploring the Potential of Context-Aware Dynamic CPU Undervolting},

author = {Emmanouil Maroudas and Christos D. Antonopoulos and Nikolaos Bellas and Spyros Lalis},

year  = {2021},

date = {2021-05-01},

journal = {18th ACM International Conference on Computing Frontiers (CF '21)},

address = {Virtual Conference},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{356,

title = {Reducing the Mission Time of Drone Applications through Location-Aware Edge Computing},

author = {Theodoros Kasidakis and Giorgos Polychronis and Manos Koutsoubelias and Spyros Lalis},

year  = {2021},

date = {2021-05-01},

journal = {5th IEEE International Conference on Fog and Edge Computing (ICFEC 2021)},

address = {Virtual Conference},

abstract = {In data-driven applications, which go beyond simple data collection, 

drones may need to process sensor measurements at certain locations, 

during the mission. However, the onboard computing platforms typically have strong resource limitations, which may lead to significant delays and long mission times. To address this problem, we explore the potential of offloading heavyweight computations from the drone to nearby edge computing infrastructure. We discuss a concrete implementation for a service-oriented application software stack, which takes offloading decisions based on the expected service invocation 

time and the locations of the servers expected to be available in the mission area. We evaluate our implementation using an experimental setup that combines a hardware-in-the-loop and software-in-the-loop configuration. Our results show that the proposed approach can reduce the total mission time significantly, by up to 48% vs local-only processing, and by 10% vs more naive opportunistic offloading, depending on the mission scenario.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{371,

title = {Dynamic Multiple Vehicle Routing under Energy Capacity Constraints},

author = {Giorgos Polychronis and Spyros Lalis},

doi = {10.1109/itsc45102.2020.9294492},

year  = {2020},

date = {2020-09-01},

journal = {2020 IEEE 23rd International Conference on Intelligent Transportation Systems (ITSC)},

publisher = {IEEE},

address = {Rhodes, Greece},

abstract = {The multiple vehicle routing problem (mVRP) concerns the scheduling of multiple vehicles so as to visit some locations of interest. We study a dynamic version of mVRP where the travel costs are not a priori known and may vary at runtime. Moreover, we introduce energy-related constraints which make the problem more complex. Vehicles have only finite energy reserves, which gradually diminish as they move between different locations, but can also gain some energy at specific depot locations. The objective is to visit all locations of interest as fast as possible without any vehicle exhausting its energy. We propose an online algorithm based on the Large Neighbourhood Search (LNS) heuristic. We evaluate the algorithm for different topologies and degrees of vehicle autonomy. Our results show that it achieves significantly better results than an offline algorithm that produces a safe schedule based on worst-case cost estimates.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{178,

title = {Flexible Deployment and Enforcement of Flight and Privacy Restrictions for Drone Applications},

author = {Nasos Grigoropoulos and Spyros Lalis},

url = {https://doi.ieeecomputersociety.org/10.1109/DSN-W50199.2020.00029},

doi = {10.1109/DSN-W50199.2020.00029},

year  = {2020},

date = {2020-06-01},

journal = {2020 50th Annual IEEE/IFIP International Conference on Dependable Systems and Networks Workshops (DSN-W)},

pages = {110-117},

publisher = {IEEE Computer Society},

address = {Virtual Conference},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{358,

title = {Increasing the Profit of Cloud Providers through DRAM Operation at Reduced Margins},

author = {Christos Kalogirou and Christos D. Antonopoulos and Nikolaos Bellas and Spyros Lalis and Lev Mukhanov and Georgios Karakonstantis},

doi = {10.1109/ccgrid49817.2020.00-38},

isbn = {9781728160955},

year  = {2020},

date = {2020-05-01},

journal = {2020 20th IEEE/ACM International Symposium on Cluster, Cloud and Internet Computing (CCGRID)},

publisher = {IEEE},

address = {Virtual Conference},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{180,

title = {Tournament Selection Algorithm for the Multiple Travelling Salesman Problem},

author = {Giorgos Polychronis and Spyros Lalis},

editor = {Karsten Berns and Markus Helfert and Oleg Gusikhin},

url = {https://doi.org/10.5220/0009564905850594},

doi = {10.5220/0009564905850594},

isbn = {9789897584190},

year  = {2020},

date = {2020-05-01},

journal = {Proceedings of the 6th International Conference on Vehicle Technology and Intelligent Transport Systems},

pages = {585-594},

publisher = {SCITEPRESS},

address = {Virtual Conference},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{179,

title = {Byzantine fault tolerance for centrally coordinated missions with unmanned vehicles},

author = {Nasos Grigoropoulos and Manos Koutsoubelias and Spyros Lalis},

url = {https://doi.org/10.1145/3387902.3392622},

doi = {10.1145/3387902.3392622},

isbn = {9781450379564},

year  = {2020},

date = {2020-05-01},

journal = {Proceedings of the 17th ACM International Conference on Computing Frontiers},

pages = {165-173},

publisher = {ACM},

address = {Virtual Conference},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{378,

title = {Simulation and Digital Twin Support for Managed Drone Applications},

author = {Nasos Grigoropoulos and Spyros Lalis},

year  = {2020},

date = {2020-01-01},

journal = {IEEE/ACM International Symposium on Distributed Simulation and Real Time Applications (DS-RT)},

pages = {198-205},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{380,

title = {Fractus: Orchestration of Distributed Applications in the Drone-Edge-Cloud Continuum},

author = {Nasos Grigoropoulos},

year  = {2019},

date = {2019-06-01},

journal = {Proc. 46th IEEE Annual Computers, Software and Applications Conference (COMPSAC 2022)},

address = {Virtual Conference},

abstract = {This work presents an orchestration framework for the automated deployment of component-based applications in the drone-edge-cloud continuum, which provides users with abstractions for describing the application’s placement and communication requirements, allocates resources in a mission-aware fashion by considering the drone operation area, establishes and maintains connectivity between components by transparently leveraging different networking capabilities, and tackles safety and privacy issues via policy-based access to mobility and sensor resources.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{186,

title = {Comparative Performance Analysis of Vulkan Implementations of Computational Applications},

author = {Maria Rafaela Gkeka and Nikolaos Bellas and Christos D. Antonopoulos},

url = {https://doi.org/10.1145/3318170.3318174},

doi = {10.1145/3318170.3318174},

isbn = {9781450362306},

year  = {2019},

date = {2019-05-01},

journal = {Proceedings of the International Workshop on OpenCL},

pages = {6:1},

publisher = {ACM},

address = {Boston, MA},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{185,

title = {Active Replication for Centrally Coordinated Teams of Autonomous Vehicles},

author = {Nasos Grigoropoulos and Manos Koutsoubelias and Spyros Lalis},

url = {http://10.64.82.15/csl/wp-content/uploads/2019/09/dcoss19_nasos-1.pdf https://doi.org/10.1109/DCOSS.2019.00038},

doi = {10.1109/DCOSS.2019.00038},

isbn = {9781728105703},

year  = {2019},

date = {2019-05-01},

journal = {2019 15th International Conference on Distributed Computing in Sensor Systems (DCOSS)},

pages = {114-122},

publisher = {IEEE},

address = {Santorini, Greece},

abstract = {Autonomous vehicles, drones in particular, are used to support a wide range of sensing and actuating missions. While these missions are typically coordinated by a human operator, itis attractive to automate this coordination through a computer program that retrieves information from the vehicles and issues commands to them according to the mission objectives. However, the fact that such a computer-driven system may interact with and affect the physical environment in a direct way, introduces several challenges. In particular, it is important to tolerate failures of the mission control computer as smoothly as possible,avoiding roll-backs that might lead to inconsistencies. To address this problem, we propose an active replication approach, ensuring that as long as at least one replica of the mission controller remains operational, the mission will progress in a consistent way and with full transparency for the mission program. We define the properties that should be satisfied to achieve the required consistency, and present system-level mechanisms that support both deterministic and non-deterministic mission programs. We then discuss a concrete implementation of the proposed approach for an existing programming framework targeting multi-drone applications. Finally, we give an analytical cost model for the communication overhead of the proposed approach, and report the actual execution delay incurred in our prototype implementation for indicative scenarios using a suitable simulation environment.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{184,

title = {Exploiting CPU Voltage Margins to Increase the Profit of Cloud Infrastructure Providers},

author = {Christos Kalogirou and Panos Koutsovasilis and Christos D. Antonopoulos and Nikolaos Bellas and Spyros Lalis and Srikumar Venugopal and Christian Pinto},

url = {http://10.64.82.15/csl/wp-content/uploads/2019/09/ccgrid19.pdf http://10.64.82.15/csl/wp-content/uploads/2019/10/ccGrid19_poster.pdf https://doi.org/10.1109/CCGRID.2019.00044},

doi = {10.1109/CCGRID.2019.00044},

isbn = {9781728109121},

year  = {2019},

date = {2019-05-01},

journal = {2019 19th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing (CCGRID)},

pages = {302-311},

publisher = {IEEE},

address = {Larnaca, Cyprus},

abstract = {Energy efficiency is a major concern for cloud computing, with CPUs accounting a significant fraction of datacenter nodes power consumption. CPU manufacturers introduce voltage margins to guarantee correct operation. However, these are unnecessarily wide for real-world execution scenarios, and 

translate to increased power consumption. In this paper, we investigate how such margins can be exploited by infrastructure operators, by selectively undervolting nodes, at the controlled 

risk of inducing failures and activating service-level agreement (SLA) violation penalties. We model the problem in a formal way, capturing the most important aspects that drive VM management and system configuration decisions. Then, we introduce XM-VFS policy that reduces infrastructure operator costs by reducing voltage margins, and compare it with the state-of-the-art which employs dynamic voltage-frequency scaling (DVFS) and workload consolidation. We perform simulations to quantify the cost reduction, considering the energy consumption and potential SLA violations. Our results show significant gains, up to 17.35% and 

16.32% for the energy and cost reduction respectively. In our simulations, we use realistic assumptions for voltage margins, energy consumption and performance degradation of applications due to frequency scaling, based on the characterization of commercial Intel- and ARM-based machines. Our model and scheduling policy are generic and scalable.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{183,

title = {Dynamic Vehicle Routing under Uncertain Travel Costs and Refueling Opportunities},

author = {Giorgos Polychronis and Spyros Lalis},

url = {https://doi.org/10.5220/0007673900520063},

doi = {10.5220/0007673900520063},

isbn = {9789897583742},

year  = {2019},

date = {2019-05-01},

journal = {Proceedings of the 5th International Conference on Vehicle Technology and Intelligent Transport Systems},

pages = {52-63},

publisher = {SCITEPRESS - Science and Technology Publications},

address = {Heraklion, Greece},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{195,

title = {Exploring the Effects of Code Optimizations on CPU Frequency Margins},

author = {Konstantinos Parasyris and Nikolaos Bellas and Christos D. Antonopoulos and Spyros Lalis},

url = {https://doi.org/10.1007/978-3-030-02465-9_42},

doi = {10.1007/978-3-030-02465-9_42},

year  = {2018},

date = {2018-06-01},

journal = {Workshop in Approximate and Transprecision Computing on Emerging Technologies (ATCET), in conjunction with the International Supercomputing Conference (ISC)},

pages = {579-587},

address = {Frankfurt, Germany},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{193,

title = {A Framework for Evaluating Software on Reduced Margins Hardware},

author = {Konstantinos Parasyris and Panos Koutsovasilis and Vassilis Vassiliadis and Christos D. Antonopoulos and Nikolaos Bellas and Spyros Lalis},

url = {https://doi.org/10.1109/DSN.2018.00043},

doi = {10.1109/DSN.2018.00043},

year  = {2018},

date = {2018-06-01},

journal = {48th International Conference on Dependable Systems and Networks (DSN)},

pages = {330-337},

address = {Luxemburg},

abstract = {To improve power efficiency, researchers are experimenting with dynamically adjusting the voltage and frequency margins of systems to just above the minimum required for reliable operation. Traditionally, manufacturers did not allow reducing these margins. Consequently, existing studies use system simulators, or software fault-injection methodologies, which are slow, inaccurate and cannot be applied on realistic workloads. However recent CPUs allow the operation outside the nominal voltage/frequency envelope. We present eXtended Margins eXperiment Manager (XM 2 ) which enables the evaluation of software on systems operating outside their nominal margins. It supports both bare-metal and OS-controlled execution using an API to control the fault injection procedure and provides automatic management of experimental campaigns. XM 2 requires, on average, 5.6% extra lines of code and increases the application execution time by 2.5%. To demonstrate the flexibility of XM 2 , we perform three case studies: two employing bare-metal execution on a raspberry PI, and one featuring a full-fledged software stack (including OS) on an Intel Skylake Xeon processor.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{191,

title = {Fault- Tolerance Support for Mobile Robotic Applications},

author = {Manos Koutsoubelias and Spyros Lalis},

url = {https://doi.org/10.1109/SIES.2018.8442098},

doi = {10.1109/SIES.2018.8442098},

year  = {2018},

date = {2018-06-01},

journal = {13th IEEE International Symposium on Industrial Embedded Systems, (SIES)},

pages = {1-10},

address = {Graz, Austria},

abstract = {The advent of powerful yet also affordable mobile robotic platforms will spur a new generation of computer-driven applications that employ multiple mobile robots to perform a large variety of missions. This prospect has lead to the emergence of corresponding programming models that aim to ease the development of such applications, allowing a more straightforward exploitation of the resources that are available on these platforms. But fault-tolerance remains a challenging issue due to the inherent dynamics of such cyber-physical systems. Notably, some of the actions that are performed in the context of such executions cannot be easily undone, while in other cases it may be problematic to automatically redo certain actions without the explicit control of the application. The desired functionality cannot be achieved by applying traditional fault-tolerance schemes out-of-the-box; these need to be combined and extended in a suitable manner. In this paper, we present system-level support designed to provide transparent fault-tolerance for applications that coordinate multiple mobile robots in a centralized way. We discuss a concrete implementation of the proposed approach as part of an existing programming framework. Also, we present an evaluation of the respective overhead for individual runtime operations as well as for indicative application scenarios with and without failures.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{192,

title = {Scalable and Adaptive Polling Protocol for ConcurrentWireless Sensor Data Flows},

author = {Manos Koutsoubelias and Antonios Argyriou and Spyros Lalis},

url = {https://doi.org/10.1109/PERCOMW.2018.8480129},

doi = {10.1109/PERCOMW.2018.8480129},

year  = {2018},

date = {2018-03-01},

journal = {IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops)},

pages = {409-414},

address = {Athens, Greece},

abstract = {The uncoordinated transmission of sensor measure- ments to a collector over simple wireless technologies can lead to severely degraded performance when operating close to channel capacity. In this case, it can be far more effective to let the collector poll the sensor nodes to retrieve their data. We propose a coordinated protocol that exploits the broadcast ca- pability of the wireless channel to eliminate contention between nodes and to minimize the number of packet transmissions performed at each poll. Furthermore, to let the protocol follow the dynamic changes in the sensor data generation rate, we propose an application-agnostic method for estimating the data generation rate of each node locally, and extend the protocol so that the collector dynamically adjusts the polling rate accordingly. Our method is based on a Kalman filter tuned for stable data generation rates, which is controlled via simple signals generated at runtime by the underlying polling protocol. We experimentally evaluate an implementation of our protocol for different data traffic scenarios using real nodes that communicate with the collector over IEEE 802.15.4 radio, showing that the collector can successfully track the actual data rate for both periodic and stochastic data generation.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{187,

title = {A modular simulation environment for multiple UAVs with virtual WiFi and sensing capability},

author = {Manos Koutsoubelias and Nasos Grigoropoulos and Spyros Lalis},

url = {https://doi.org/10.1109/SAS.2018.8336766},

doi = {10.1109/SAS.2018.8336766},

year  = {2018},

date = {2018-03-01},

journal = {IEEE Sensors Applications Symposium, (SAS)},

pages = {1-6},

address = {Seoul, South Korea},

abstract = {Experiments with real unmanned aerial vehicles (UAVs) need considerable preparation, raise safety concerns, often require official flight permissions by authorities, and can be very costly in case of hardware or software malfunctions. Therefore, simulation is an attractive alternative for performing first tests before going out in the field. This paper presents AeroLoop, a modular simulation environment that combines mature simulation and virtualization technologies into a single system for conducting application experiments with multiple virtual UAVs (vUAVs). Besides the flight behavior of each vUAV, AeroLoop supports simulated wireless communication between them. Also, each vUAV has a virtual camera sensor that can be used to take vertical snapshots during the flight. We discuss key design and implementation aspects of the AeroLoop system, and provide a functional evaluation of the main simulation components.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{361,

title = {Facilitating Widespread Adoption of Edge Computing through Development of a Universal Microserver Architecture and Software Ecosystem},

author = {Andreas Diavastos and Christos D. Antonopoulos},

year  = {2018},

date = {2018-01-01},

journal = {International Conference on High Performance Embedded Architectures and Compilers, (HiPEAC). Poster presentation},

address = {Manchester, UK},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{205,

title = {A programming model and runtime system for approximation-aware heterogeneous computing},

author = {Ioannis Parnassos and Nikolaos Bellas and Nikolaos Katsaros and Nikolaos Patsiatzis and Athanasios Gkaras and Konstantinos Kanellis and Christos D. Antonopoulos and Michalis Spyrou and Emmanouil Maroudas},

url = {https://doi.org/10.23919/FPL.2017.8056774},

doi = {10.23919/FPL.2017.8056774},

year  = {2017},

date = {2017-09-01},

journal = {International Symposium on Field Programmable Logic and Applications (FPL)},

pages = {1-4},

address = {Ghent, Belgium},

abstract = {Heterogeneous platforms that include diverse architectures such as multicore CPUs, FPGAs and GPUs are becoming very popular due to their superior performance and energy efficiency. Besides heterogeneity, a promising approach for minimizing energy consumption is through approximate computing which relaxes the requirement that all parts of a program are considered equally important to the output quality, thus, all should be executed at full accuracy. Our work extends a traditional OpenMP-like programming model and runtime system to support seamless execution on hybrid architectures with approximation semantics. Starting from a common application code, annotated with our programming model, the programmer can not only target heterogeneous architectures comprising CPU, FPGA and GPU components, but can also regulate the amount of approximation. We evaluate our framework on a number of large-scale applications and demonstrate that the combination of heterogeneous and approximate computing can provide a powerful dynamic interplay between performance and output quality.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{204,

title = {Flexible Distributed Computing Across End-Devices, the Edge and the Cloud},

author = {Alexandros Patras and Spyros Lalis and Christos D. Antonopoulos},

url = {https://doi.org/10.3233/978-1-61499-843-3-794},

doi = {10.3233/978-1-61499-843-3-794},

year  = {2017},

date = {2017-09-01},

journal = {Parallel Computing (PARCO)},

pages = {794-803},

address = {Bologna, Italy},

abstract = {The emergence of the edge/fog computing paradigm has increased the programming complexity of applications so that they can work seamlessly in the new distributed and heterogeneous system landscape. In this paper, we investigate a structured dataflow approach which simplifies application development and offers great flexibility regarding the deployment of the application across end-devices, edge computing infrastructure and remote cloud systems. Our prototype is built on top of the Node-RED framework, with extensions in order to support the transparent deployment and distributed execution of application flows. We use a real-world application example to illustrate our approach as well as to explore the performance trade-offs for different deployment scenarios on a real distributed computing setup.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{203,

title = {Edge and Cloud Provider Cost Minimization by Exploiting Extended Voltage and Frequency Margins},

author = {Christos Kalogirou and Panos Koutsovasilis and Emmanouil Maroudas and Christos D. Antonopoulos and Spyros Lalis and Nikolaos Bellas},

url = {https://doi.org/10.3233/978-1-61499-843-3-814},

doi = {10.3233/978-1-61499-843-3-814},

year  = {2017},

date = {2017-09-01},

journal = {Parallel Computing (PARCO)},

pages = {814-823},

address = {Bologna, Italy},

abstract = {Energy costs contribute significantly to the total cost of operation for cloud and edge infrastructure providers. Both conventional (Voltage and Frequency Scaling) and more aggressive (undervolting, overclocking) techniques can be applied to reduce the energy footprint of the infrastructure and thus the cost of the operator. However, these techniques may affect the quality of service (QoS), potentially activating service level agreement (SLA) violation penalties for the provider. In this paper we model and study this tradeoff. We find that undervolting is the most effective of the three techniques in reducing infrastructure operation cost. We identify optimal operating points, and we study the effect of different parameters, such as the severity of SLA penalties, the length of the job and the existence of error protection mechanisms, on the optimal operating point and the extent of potential benefits.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{202,

title = {Scheduling Policies for Heterogeneous, Approximate Computing Systems},

author = {Christos Kalogirou and Michalis Spyrou and Konstantinos Theodosiou and Christos D. Antonopoulos},

url = {http://doi.acm.org/10.1145/3139367.3139428},

doi = {10.1145/3139367.3139428},

year  = {2017},

date = {2017-09-01},

journal = {21st Pan-Hellenic Conference on Informatics (PCI)},

pages = {1-43},

address = {Larissa, Greece},

abstract = {Energy consumption is a primary concern for modern computer systems. Conservative approaches, such as DVFS, which have been used in the past to optimize the performance / power tradeoff have reached their limits. Heterogeneity is a promising approach: devices with different characteristics, each performance- and energy-efficient for specific computational patterns are combined in the same system. Approximate computing is another more disruptive solution: many applications can tolerate controlled quality loss in exchange to significant improvement of performance and energy footprint. In this paper we introduce three scheduling policies that exploit heterogeneity, one of them combining it with approximate computing. These policies can selectively optimize performance, energy consumption, or the tradeoff between energy consumption and quality of results. They monitor the execution of tasks at runtime in order to identify the appropriate mapping of tasks to devices, as well as to control the degree of approximation. Our experimental evaluation indicates that all three policies closely match the effectiveness of the optimal configuration, selected by an "oracle".},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{198,

title = {Virtual Sensor Services for Simulated Mobile Nodes},

author = {Manos Koutsoubelias and Nasos Grigoropoulos and Spyros Lalis},

url = {https://doi.org/10.1109/SAS.2017.7894115},

doi = {10.1109/SAS.2017.7894115},

year  = {2017},

date = {2017-04-01},

journal = {IEEE Sensors Applications Symposium (SAS)},

pages = {1-6},

publisher = {IEEE},

address = {Glassboro, NJ},

abstract = {The faithful and flexible simulation of mobile robotic platforms with different application-specific sensing capabilities will become increasingly important in order to test a wide range of scenarios without having to run real missions. Current research focuses primarily on the mobility dynamics of such systems, and to this end a lot of work has already been done to support the simulation of various land, surface, underwater and aerial vehicles. We tackle a complementary aspect, namely that of sensing. More concretely, we propose to support virtual sensors via a service-oriented architecture, which cleanly separates a simulated vehicle from the logic that provides the (artificial) sensor values to it. The application running on the simulated vehicle has the illusion of accessing a real onboard sensor, but sensor data is provided by an independent software component, which can be flexibly placed on the same machine that runs the simulated vehicle, or on a remote host. This paper introduces the concept, describes a proof-of-concept implementation, and provides an evaluation that identifies the limits of the proposed approach.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}

@proceedings{209,

title = {An open framework for flexible plug-in privacy mechanisms in crowdsensing applications},

author = {Manos Katsomallos and Spyros Lalis and Thanasis Papaioannou and George Theodorakopoulos},

url = {https://doi.org/10.1109/PERCOMW.2017.7917564},

doi = {10.1109/PERCOMW.2017.7917564},

year  = {2017},

date = {2017-03-01},

journal = {IEEE International Conference on Pervasive Computing and Communications Workshops (PerCom Workshops)},

pages = {237-242},

address = {Kona, HI},

abstract = {Preserving user privacy is crucial for the wide adoption of crowdsensing and participatory sensing applications that rely on personal devices. Currently, each application comes with its own hardwired and possibly undocumented privacy support (if any), while the horizontal protection mechanisms provided by operating and runtime systems operate at a low level that can significantly harm application utility, or even render an application useless. To achieve greater flexibility, we propose a framework that decouples the privacy mechanism from the application logic so that it can be developed by another, perhaps more trusted party, and which allows the dynamic binding of different privacy mechanisms to the same application running on the user's mobile device. We describe a proof-of-concept implementation of the proposed framework for Android, where privacy mechanisms are independently developed as separate plug-in components. Based on a simple but powerful API, it is possible to implement a wide range of standard privacy approaches, including collaborative schemes that involve data exchanges among multiple personal devices.},

keywords = {},

pubstate = {published},

tppubtype = {proceedings}

}