Swedish Institute of Computer Science Publications Database
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Kapacitetsanalys av tre olika utbyggnadsalternativ av Sävenäs rangerbangård: resultat från pilotstudien av Sävenäs i projektet PRAGGE2
No full textFöljande rapport redovisar arbetet med en av två piloter i projektet PRAGGE2, undersökning av tre bangårdsalternativ för rustningen/ombyggnaden av Sävenäs rangerbangård i Göteborg. I detta arbete har en metod utvecklad under det första PRAGGE-projektet använts för att studera tre olika utvecklingsalternativ av rangerbangården i Sävenäs, framtagna av Sweco i separat projekt. PRAGGE-metoden bygger på att mäta det extra arbete i termer av att mäta det antal gånger en vagn rangeras extra på bangården på grund av trängsel, väsentligen för få spår att bygga avgående tåg på. Metoden utgår från den i utfallsdata definierade tidtabellen och bokningen och skapar en rangerplan med minimalt antal extra rangerade vagnar över vall. Green Cargo har för PRAGGE2 ställt data från 2014 års trafik till vårt förfogande. Resultatet från pilotstudien är att en av bangårdsutformningarna från Swecos tre framtagna alternativ inte bedöms ha tillräcklig kapacitet medan de två andra har utvärderats vidare. Den ena av dem bedömdes dock inte få plats på den yta som anses kunna ställas till förfogande varvid enbart ett alternativ återstår. Erfarenheten från piloten är att PRAGGE-metoden fungerar som en kvantitativ utvärderingsmetod för att bedöma kapaciteten på föreslagen grov utformning av rangerbangården och som kompletterar de kvalitativa utvärderingsmetoder som också används
Kapacitet på rangerbangården Hallsberg: resultat från projektet PRAGGE2
No full textDenna rapport beskriver dels en metod att bedöma rangerbangårdens förmåga att hantera tågbildning och dels en pilotstudie som gjorts i Hallsberg i projektet PRAGGE2. Metoden, kallad PRAGGE-metoden, bygger på att en optimerande programvara utvecklad i tidigare projekt, kallad RanPlan, används för att undersöka det extra arbete som olika bangårdsutformningar ger upphov till. Extraarbete mäts som ett nyckeltal, ER (extra valldrag), som är en funktion av antalet vagnar som får hanteras flera gånger över rangervallen. Ju högre ER-värde desto arbetsammare är det för bangården att skapa de avgående tågen. Inom ramen för denna studie har riktningsgruppens antal spår samt längder undersökts, U-gruppens betydelse för Hallsbergs rangerbangård har belysts med speciellt fokus på den nuvarande situationen med det ibland förekommande tågkön in till infartsgruppen. Vidare har en enklare undersökning av ett ev. spårbehov för s.k. ”block-swaps” (byte av ett fåtal större vagnsgrupper mellan tåg) gjorts samt även ett försök att påbörja en kategorisering eller kapacitetsbeskrivning av en rangerbangård
Analysis of the information needs of an autonomous hauler in a quarry site
No full textAbstract:
Autonomous and intelligent construction equipment is an emergent area of research, which shares many characteristics with on-road autonomous vehicles, but also have fundamental differences. Construction vehicles usually perform repetitive tasks in confined sites, such as quarries, and cooperate with other vehicles to complete common missions. A quarry can be viewed as a system-of-systems and the vehicles are individual systems within the site system. Therefore it is important to analyze the site system, i.e. included vehicles, surrounding systems, and system context, before the introduction of autonomous vehicles. It is necessary to map the needed infrastructure, and the needed input information from on-board sensors and off-board information suppliers, before designing the vehicle electronics system. This paper describes how we identified sensory and input signal needs for an autonomous articulated hauler in a scenario at a quarry site. Different architectural alternatives are evaluated and a set-up for a quarry site is suggested
Towards Earlier Fault Detection by Value-Driven Prioritization of Test Cases Using Fuzzy TOPSIS
No full textIn industrial software testing, development projects typically set up and maintain test suites containing large numbers of test cases. Executing a large number of test cases can be expensive in terms of effort and wall-clock time. Moreover, indiscriminate execution of all available test cases typically lead to sub-optimal use of testing resources. On the other hand, selecting too few test cases for execution might leave a large number of faults undiscovered. Limiting factors such as allocated budget and time constraints for testing further emphasizes the importance of test case prioritization in order to identify test cases that enable earlier detection of faults while respecting such constraints. In this paper, we propose a multi-criteria decision making approach for prioritizing test cases in order to detect faults earlier. This is achieved by applying the TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) decision making technique combined with fuzzy principles. Our solution is based on important criteria such as fault detection probability, execution time, complexity, and other test case properties. By applying the approach on a train control management subsystem from Bombardier Transportation in Sweden, we demonstrate how it helps, in a systematic way, to identify test cases that can lead to early detection of faults while respecting various criteria
A 2-Layer Component-based Architecture for Heterogeneous CPU-GPU Embedded Systems
No full textTraditional embedded systems are evolving into heterogeneous systems in order to address new and more demanding software requirements. Modern embedded systems are constructed by combining different computation units, such as traditional CPUs, with Graphics Processing Units (GPUs). Adding GPUs to conventional CPU-based embedded systems enhances the computation power but also increases the complexity in developing software applications. A method that can help to tackle and address the software complexity issue of heterogeneous systems is component-based development. The allocation of the software application onto the appropriate computation node is greatly influenced by the system information load. The allocation process is increased in difficulty when we use, instead of common CPU-based systems, complex CPU-GPU systems. This paper presents a 2-layer component-based architecture for heterogeneous embedded systems, which has the purpose to ease the software-to-hardware allocation process. The solution abstracts the CPU-GPU detailed component-based design into single software components in order to decrease the amount of information delivered to the allocator. The last part of the paper describes how the allocation process may be modified using our proposed solution, when applied on a real system demonstrator
Design Choices for the IoT in Information-Centric Networks
No full textThis paper outlines the tradeoffs involved in utilizing Information-Centric Networking (ICN) for Internet of Things (IoT) scenarios. It describes contexts and applications where the IoT would benefit from ICN, and where a hostcentric approach would be better. Requirements imposed by the heterogeneous nature of IoT networks are discussed in terms of connectivity, power availability, computational and storage capacity. Design choices are then proposed for an IoT architecture to handle these requirements, while providing efficiency and scalability. An objective is to not require any IoT specific changes of the ICN architecture per se, but we do indicate some potential modifications of ICN that would improve efficiency and scalability for IoT and other applications
Range-consistent forbidden regions of Allen's relations
No full textFor all 8192 combinations of Allen's 13 relations between one task with origin oi and fixed length li and another task with origin oj and fixed length lj, we give a formula F(min(oj), max(oj), li, lj), where min(oj) and max(oj) respectively denote the earliest and the latest origin of task j, evaluating to a set of integers which are infeasible for oi for the given combination. Such forbidden regions are useful e.g. in a range-consistency maintaining propagator for an Allen constraint in finite domain constraint programming
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, security, 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
An Industrial Survey of Safety Evidence Change Impact Analysis Practice
No full textIn many application domains, critical systems must comply with safety standards. This involves gathering safety evidence in the form of artefacts such as safety analyses, system specifications, and testing results. These artefacts can evolve during a system's lifecycle, creating a need for impact analysis to guarantee that system safety and compliance are not jeopardised. Although extensive research has been conducted on change impact analysis and on safety evidence management, the knowledge about how safety evidence change impact analysis is addressed in practice is limited. This paper reports on a survey targeted at filling this gap by analysing the circumstances under which safety evidence change impact analysis is addressed, the tool support used, and the challenges faced. We obtained 97 valid responses representing 16 application domains, 28 countries, and 47 safety standards. The results suggest that most practitioners deal with safety evidence change impact analysis during system development and mainly from system specifications. Furthermore, the level of automation in the process is low and insufficient tool support is the most frequent challenge. Other notable findings include that the different artefact types used as safety evidence seem to co-evolve, the evolution of safety case should probably be better managed, and no commercial impact analysis tool has been reported as used for all artefact types. Finally, we identified over 20 areas where the state of the practice in safety evidence change impact analysis can be improved
