Swedish Institute of Computer Science Publications Database
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Offloading Cellular Traffic with Opportunistic Networks: A Feasibility Study
No full textThe widespread diffusion of powerful mobile devices
with diverse networking and multimedia capabilities, and
the associated blossoming of content-centric multimedia services is contributing to the exponential increase of data traffic in cellular networks. Mobile data offloading is a promising technique to cope with these problems, which allows to deliver data originally targeted for cellular networks to complementary networking technologies. Among the various forms of mobile data offloading in this study we focus on offloading through opportunistic networks. Differently from previous studies in this field we evaluate the efficiency of opportunistic offloading schemes by using a real cellular traffic dataset collected in a large metropolitan area over a period of one month. We focus our analysis on video requests for popular video providers, and we evaluate the potential benefits of using an opportunistic data dissemination scheme to request this videos from local users instead of using the cellular network. As a benchmark, we compare the performance of such system with a simple caching mechanism. We show that a simple opportunistic offloading scheme can improve the performance of the caching system even if only 10% of the users participate in the opportunistic dissemination. This means that operators could offload their network efficiently without needing to deploy additional caching infrastructure
Proceedings of the 1st Scandinavian Workshop on the Engineering of Systems-of-Systems (SWESoS 2015)
No full textThe rapid digitization of society is to a large extent driven by the interconnection of existing systems in order to co-ordinate their activities. This leads to systems-of-systems (SoS), where the parts more or less voluntarily co-operate for mutual benefits while keeping their autonomy. The term SoS started to become relevant some 20 years ago, and accelerated as a research area about 10 years ago. Although some people tend to take SoS as a synonym for large and complex systems, the research community has arrived at a fairly precise characterization of the term. In an SoS, the elements, or constituent systems, exhibit an operational and managerial independence, meaning that they can operate outside the SoS context, and have different owners. They choose to collaborate in order to achieve a common goal, manifested as an emergent property of the SoS, i.e. a property not existent in any of its parts in isolation.
The field so far has been dominated by US researchers focusing on military and space applications. Key topics include architecture, communications, interoperability, modeling and simulation, and also a number of properties where dependability attributes such as safety play an important role. From its origins in the government driven sectors, SoS are now spreading to civilian and commercial usage.
To investigate the needs and strategies for Sweden in relation to SoS, VINNOVA in late 2014 commissioned a consortium led by the Swedish Institute of Computer Science (SICS) to develop a research and innovation agenda for the area. The agenda project has included an industrial perspective captured in a series of workshops with practitioners, and also a research perspective. The latter was handled through an extensive research literature review, which indicated a poor representation of Scandinavia in the SoS research community. Also, a survey was sent to all relevant Swedish universities, research institutes, and funding agencies, and the result of this was somewhat contradictory. Many researchers are indeed working on topics related to SoS, but often use different terms for it, and publish at other venues than the SoS community.
Given the large, but scattered, activity in the highly multidisciplinary SoS area, SICS and the Swedish Chapter of the International Council on Systems Engineering (INCOSE) decided to organize the 1st Scandinavian Workshop on the Engineering of Systems of Systems (SWESoS 2015). The primary purpose of the workshop was to create a meeting place for researchers and practitioners interested in SoS. The workshop was intended to be an informal event, focusing on presentation of results and ongoing research, to stimulate interaction among the researchers. This proceedings volume contains the extended abstracts of those presentations. In many cases, the presentations are based on work already published elsewhere, and the interested reader can find links to more material in each contribution.
The scope of the workshop was all aspects related to SoS engineering. This included, but was not restricted to, the following topics when applied to systems of systems: Autonomous and cooperative systems; Business models, including software ecosystems; Case studies of applications in different domains; Control strategies; Communication; Dependability, robustness, and other quality attributes; Enterprise architecture; Governance; Interoperability; Modeling and simulation, including multi-agent systems; Service oriented architecture; Systems engineering methods; and Systems thinking.
In total, 16 papers were submitted to the workshop, and 13 were accepted for presentation, whereas the remaining three were somewhat outside the core scope of the event
A Probabilistic Approach to Aggregating Anomalies for Unsupervised Anomaly Detection with Industrial Applications
No full textThis paper presents a novel, unsupervised approach to detecting anomalies at the collective level. The method probabilistically aggregates the contribution of the individual anomalies in order to detect significantly anomalous groups of cases. The approach is unsupervised in that as only input, it uses a list of cases ranked according to its individual anomaly score. Thus, any anomaly detection algorithm can be used for scoring individual anomalies, both supervised and unsupervised approaches. The applicability of the proposed approach is shown by applying it to an artificial data set and to two industrial data sets — detecting anomalously moving cranes (model-based detection) and anomalous fuel consumption (neighbour-based detection)
Multi-Criteria Test Case Prioritization Using Fuzzy Analytic Hierarchy Process
No full textOne of the key challenges in software testing today is prioritizing and evaluating test cases. The decision of which test cases to design, select and execute first is of great importance, in particular considering that testing is often done late in the implementation process, and therefore needs to be done within tight resource constraints on time and budget. In practice, prioritized selection of test cases requires the evaluation of different test case criteria, and therefore, test case prioritization can be formulated as a multi-criteria decision making problem. As the number of decision criteria grows, application of a systematic decision making solution becomes a necessity. In this paper we propose an approach for prioritized selection of test cases by using the Analytic Hierarchy Process (AHP) technique. To improve the practicality of the approach in real world scenarios, we apply AHP in fuzzy environment so that criteria values can be specified using fuzzy variables than requiring precise quantified values. One of the advantages of the decision making process it that the defined criteria with the biggest and most critical role in priority ranking of test cases is identified. We have applied our approach on an example case in which several test cases for testing non-functional requirements in a systems are defined
Proposed Design Choices for IoT over Information Centric Networking
No full textThis document discusses and describes design choices made in order to utilize Information Centric Networking (ICN) for the Internet of Things (IoT). Based on requirements and challenges identified in draft-zhang-icnrg-iotchallenges-00, we propose design choices for an IoT architecture to handle these requirements, while providing efficiency and scalability. An objective is to, as far as possible, not require IoT specific changes of the ICN architectures per se, but we do indicate some potential modifications of ICN that would improve efficiency and scalability for IoT and other applications.
Furthermore, the document starts outlining how to map the proposed design choices to existing ICN architectures, in a first instance shown for CCN1.0
Requirements and Challenges for IoT over ICN
No full textThe Internet of Things (IoT) promises to connect billions of objects to the Internet. After deploying many stand-alone IoT systems in different domains, the current trend is to develop a common, "thin waist" of protocols forming a horizontal unified, defragmented IoT platform. Such a platform will make objects accessible to applications across organizations and domains. Towards this goal, quite a few proposals have been made to build a unified host-centric IoT platform as an overlay on top of today's host-centric Internet. However, there is a fundamental mismatch between the host-centric nature of todays Internet and the information-centric nature of the IoT system. To address this mismatch, we propose to build a common set of protocols and services, which form an IoT platform, based on the Information Centric Network (ICN) architecture, which we call ICN-IoT. ICN-IoT leverages the salient features of ICN, and thus provides seamless mobility support, scalability, and efficient content and service delivery.
This draft describes representative IoT requirements and ICN challenges to realize a unified ICN-IoT framework. Towards this, we first identify a list of important requirements which a unified IoT architecture should have to support tens of billions of objects, then we discuss how the current IP-IoT overlay fails to meet these requirements, followed by discussion on suitability of ICN for IoT.
Though we see most of the IoT requirements can be met by ICN, we discuss specific challenges ICN has to address to satisfy them. Then we provide discussion of popular IoT scenarios including the "smart" home, campus, grid, transportation infrastructure, healthcare, Education, and Entertainment for completeness, as specific scenarios requires appropriate design choices and architectural considerations towards developing an ICN-IoT solution
Observing Software-defined Networks Using a Decentralized Link Monitoring Approach
No full textScalable and automated monitoring processes for testing, debugging, and operation of VNFs and service-chains are crucial components towards achieving the aims of network softwarization - i.e., cheaper, faster, and shorter service deployment and network management processes. In this paper we present a decentralized monitoring approach aimed at supporting automated deployment and operation of VNFs and service-chains. The approach is inspired by network tomography and is designed to address observability limitations and scalability issues that arise from performing measurements from an SDN controller. From successive end-to-end measurements link metrics are derived via in-network parameter estimation with no need of forwarding raw measurements to the controller, which significantly reduces the measurement overhead compared to when monitoring individual links explicitly from an SDN controller
Platform for Benchmarking of RF-based Indoor Localization Solutions
No full textOver the last years, the number of indoor localization solutions has grown exponentially and a wide variety of different technologies and approaches is being explored. Unfortunately, there is currently no established standardized evaluation method for comparing their performance. As a result, each solution is evaluated in a different environment using proprietary evaluation metrics. Consequently, it is currently extremely hard to objectively compare the performance of multiple localization solutions with each other. To address the problem, we present the EVARILOS Benchmarking Platform, which enables an automated evaluation and comparison of multiple solutions in different environments and using multiple evaluation metrics. We propose a testbed independent benchmarking platform, combined with multiple testbed dependent plug-ins for executing experiments and storing performance results. The platform implements the standardized evaluation method described in the EVARILOS Benchmarking Handbook, which is aligned with the upcoming ISO/IEC 18305 standard “Test and Evaluation of Localization and Tracking Systems”. The platform and the plugins can be used in real-time on existing wireless testbed facilities, while also supporting a remote offline evaluation method using precollected data traces. Using these facilities, and by analyzing and comparing the performance of three different localization solutions, we demonstrate the need for objective evaluation methods that consider multiple evaluation criteria in different environments
Optimization Methods for Multistage Freight Train Formation
No full textThis paper considers mathematical optimization for the multistage train formation problem, which at the core is the allocation of classification yard formation tracks to outbound freight trains, subject to realistic constraints on train scheduling, arrival and departure timeliness, and track capacity. The problem formulation allows the temporary storage of freight cars on a dedicated mixed-usage track. This real-world practice increases the capacity of the yard, measured in the number of simultaneous trains that can be successfully handled. Two optimization models are proposed and evaluated for the multistage train formation problem. The first one is a column-based integer programming model, which is solved using branch and price. The second model is a simplified reformulation of the first model as an arc-indexed integer linear program, which has the same linear programming relaxation as the first model. Both models are adapted for rolling horizon planning and evaluated on a five-month historical data set from the largest freight yard in Scandinavia. From this data set, 784 instances of different types and lengths, spanning from two to five days, were created. In contrast to earlier approaches, all instances could be solved to optimality using the two models. In the experiments, the arc-indexed model proved optimality on average twice as fast as the column-based model for the independent instances, and three times faster for the rolling horizon instances. For the arc-indexed model, the average solution time for a reasonably sized planning horizon of three days was 16 seconds. Regardless of size, no instance took longer than eight minutes to be solved. The results indicate that optimization approaches are suitable alternatives for scheduling and track allocation at classification yards