# Digitala Vetenskapliga Arkivet

Ändra sökning
Avgränsa sökresultatet
45678910 301 - 350 av 715
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
• apa
• ieee
• modern-language-association-8th-edition
• vancouver
• Annat format
Fler format
Språk
• de-DE
• en-GB
• en-US
• fi-FI
• nn-NO
• nn-NB
• sv-SE
• Annat språk
Fler språk
Utmatningsformat
• html
• text
• asciidoc
• rtf
Träffar per sida
• 5
• 10
• 20
• 50
• 100
• 250
Sortering
• Standard (Relevans)
• Författare A-Ö
• Författare Ö-A
• Titel A-Ö
• Titel Ö-A
• Publikationstyp A-Ö
• Publikationstyp Ö-A
• Äldst först
• Nyast först
• Disputationsdatum (tidigaste först)
• Disputationsdatum (senaste först)
• Standard (Relevans)
• Författare A-Ö
• Författare Ö-A
• Titel A-Ö
• Titel Ö-A
• Publikationstyp A-Ö
• Publikationstyp Ö-A
• Äldst först
• Nyast först
• Disputationsdatum (tidigaste först)
• Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
• 301.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Visuell presentation av övervakningsdata2014Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)

Systemövervakning har blivit en stor del av företags IT-strukturer eftersom företag förlitar sig mer och mer på en välfungerande och högt presterande IT- struktur. När det sker problem i företags IT-strukturer så krävs det att de löses under relativt kort tid. För att hitta problemet så krävs det en mängd olika system som skall underlätta arbetet för människor som arbetar med systemövervakning och underhåll av IT-strukturer.

För att tolka och bearbeta all den information som en IT-struktur tillhandahåller så krävs det system vars uppgift är att hjälpa människor att tolka den enorma mängd data en IT-struktur genererar. Denna rapport ger en beskrivning över hur arbetet för en systemadministratör kan förenklas med hjälp av ett integrerat övervakningssystem. Stora delar av rapporten kommer fokusera på vilken metod och protokoll som kan användas för att hämta information från olika övervakningssystem och även förslag på hur informationen kan presenteras för användaren.

Visuell presentation av övervakningsdata
• 302.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Parallelization of Aggregated FMUs using Static Scheduling2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

This thesis implements and evaluates static scheduling for aggregated FMUs. An aggregate FMU is several coupled FMUs placed in a single FMU. The implementation creates task graphs from the internal dependencies and connections between the coupled FMUs. These task graphs are then scheduled using two different list scheduling heuristics, MCP and HLFET. The resulting schedules are then executed in parallel by using OpenMP in the runtime. The implementation is evaluated by looking at the utilization of the schedule, the execution time of the scheduling and the speedup of the simulation. These measurements are taken on three different test models. With model exchange FMUs only a really small speedup is observed. With co-simulation models the speedup varies a lot depending on the model, the highest achieved speedup was 2.8 running on four cores.

fulltext
• 303.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Code Generation and Global Optimization Techniques for a Reconfigurable PRAM-NUMA Multicore Architecture2014Licentiatavhandling, monografi (Övrigt vetenskapligt)

In this thesis we describe techniques for code generation and global optimization for a PRAM-NUMA multicore architecture. We specifically focus on the REPLICA architecture which is a family massively multithreaded very long instruction word (VLIW) chip multiprocessors with chained functional units that has a reconfigurable emulated shared on-chip memory. The on-ship memory system supports two execution modes, PRAM and NUMA, which can be switched between at run-time.PRAM mode is considered the standard execution mode and targets mainly applications with very high thread level parallelism (TLP). In contrast, NUMA mode is optimized for sequential legacy applications and applications with low amount of TLP. Different versions of the REPLICA architecture have different number of cores, hardware threads and functional units. In order to utilize the REPLICA architecture efficiently we have made several contributionsto the development of a compiler for REPLICA target code generation. It supports both code generation for PRAM mode and NUMA mode and can generate code for different versions of the processor pipeline (i.e. for different numbers of functional units). It includes optimization phases to increase the utilization of the available functional units. We have also contributed to quantitative the evaluation of PRAM and NUMA mode. The results show that PRAM mode often suits programs with irregular memory access patterns and control flow best while NUMA mode suites regular programs better. However, for a particular program it is not always obvious which mode, PRAM or NUMA, will show best performance. To tackle this we contributed a case study for generic stencil computations, using machine learning derived cost models in order to automatically select at runtime which mode to execute in. We extended this to also include a sequence of kernels.

Code Generation and Global Optimization Techniques for a Reconfigurable PRAM-NUMA Multicore Architecture
omslag
presentationsbild
• 304.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. VTT Technical Research Centre of Finland.
A Quantitative Comparison of PRAM based Emulated Shared Memory Architectures to Current Multicore CPUs and GPUs2014Ingår i: 27th International Conference on Architecture of Computing Systems (ARCS), 2014, ARCS Workshops: Proc. PASA-2014 11th Workshop on Parallel Systems and Algorithms, Lübeck, Germany, Lübeck, Germany: VDE Verlag GmbH, 2014, s. 27-33Konferensbidrag (Refereegranskat)

The performance of current multicore CPUs and GPUs is limited in computations making frequent use of communication/synchronization between the subtasks executed in parallel. This is because the directory-based cache systems scale weakly and/or the cost of synchronization is high. The Emulated Shared Memory (ESM) architectures relying on multithreading and efficient synchronization mechanisms have been developed to solve these problems affecting both performance and programmability of current machines. In this paper, we compare preliminarily the performance of three hardware implemented ESM architectures with state-of-the-art multicore CPUs and GPUs. The benchmarks are selected to cover different patterns of parallel computation and therefore reveal the performance potential of ESM architectures with respect to current multicores.

• 305.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Optimized selection of runtime mode for the reconfigurable PRAM-NUMA architecture REPLICA using machine-learning2014Ingår i: Euro-Par 2014: Parallel Processing Workshops: Euro-Par 2014 International Workshops, Porto, Portugal, August 25-26, 2014, Revised Selected Papers, Part II / [ed] Luis Lopes et al., Springer-Verlag New York, 2014, s. 133-145Konferensbidrag (Refereegranskat)

The massively hardware multithreaded VLIW emulated shared memory (ESM) architecture REPLICA has a dynamically reconfigurable on-chip network that offers two execution modes: PRAM and NUMA. PRAM mode is mainly suitable for applications with high amount of thread level parallelism (TLP) while NUMA mode is mainly for accelerating execution of sequential programs or programs with low TLP. Also, some types of regular data parallel algorithms execute faster in NUMA mode. It is not obvious in which mode a given program region shows the best performance. In this study we focus on generic stencil-like computations exhibiting regular control flow and memory access pattern. We use two state-of-the art machine-learning methods, C5.0 (decision trees) and Eureqa Pro (symbolic regression) to select which mode to use.We use these methods to derive different predictors based on the same training data and compare their results. The accuracy of the best derived predictors are 95% and are generated by both C5.0 and Eureqa Pro, although the latter can in some cases be more sensitive to the training data. The average speedup gained due to mode switching ranges between 1.92 to 2.23 for all generated predictors on the evaluation test cases, and using a majority voting algorithm, based on the three best predictors, we can eliminate all misclassifications.

• 306.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Optimized variant-selection code generation for loops on heterogeneous multicore systems2016Ingår i: Parallel Computing: On the Road to Exascale / [ed] Gerhard R. Joubert; Hugh Leather; Mark Parsons; Frans Peters; Mark Sawyer, IOS Press, 2016, s. 103-112Konferensbidrag (Refereegranskat)

We consider the general problem of generating code for the automated selection of the expected best implementation variants for multiple subcomputations on a heterogeneous multicore system, where the program's control flow between the subcomputations is structured by sequencing and loops. A naive greedy approach as applied in previous works on multi-variant selection code generation would determine the locally best variant for each subcomputation instance but might miss globally better solutions. We present a formalization and a fast algorithm for the global variant selection problem for loop-based programs. We also show that loop unrolling can additionally improve performance, and prove an upper bound of the unroll factor which allows to keep the run-time space overhead for the variant-dispatch data structure low. We evaluate our method in case studies using an ARM big.LITTLE based system and a GPU based system where we consider optimization for both energy and performance.

• 307.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska fakulteten.
Trends and Detection Avoidance of Internet-Connected Industrial Control Systems2019Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 7, s. 155504-155512Artikel i tidskrift (Refereegranskat)

The search engine Shodan crawls the Internet for, among other things, Industrial Control Systems (ICS). ICS are devices used to operate and automate industrial processes. Due to the increasing popularity of the Internet, these devices are getting more and more connected to the Internet. These devices will, if not hidden, be shown on Shodan. This study uses Shodan, together with data found by other researches to plot the trends of these ICS devices. The studied trends focus on the country percentage distribution and the usage of ICS protocols. The results show that all studied countries, except the United States, have decreased their percentage of world total ICS devices. We suspect that this does not represent the real story, as companies are getting better at hiding their devices from online crawlers. Our results also show that the usage of old ICS protocols is increasing. One of the explanations is that industrial devices, running old communication protocols, are increasingly getting connected to the Internet. In addition to the trend study, we evaluate Shodan by studying the time it takes for Shodan to index one of our devices on several networks. We also study ways of avoiding detection by Shodan and show that, by using a method called port knocking, it is relatively easy for a device to hide from Shodan, but remain accessible for legitimate users.

fulltext
• 308.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Collaborative Editing of Graphical Network using Eventual Consistency2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

This thesis compares different approaches of creating a collaborative editing application using different methods such as OT, CRDT and Locking. After a comparison between these methods an implementation based on CRDT was done. The implementation of a collaborative graphical network was made such that consistency is guaranteed. The implementation uses the 2P2P-Graph which was extended in order to support moving of nodes, and uses the client-server communication model. An evaluation of the implementation was made by creating a time-complexity and a space complexity analysis. The result of the thesis includes a comparison between different methods and by an evaluation of the Extended 2P2P-Graph.

fulltext
• 309.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Detecting access to sensitive data in software extensions through static analysis2019Självständigt arbete på grundnivå (kandidatexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)

Static analysis is a technique to automatically audit code without having to execute or manually read through it. It is highly effective and can scan large amounts of code or text very quickly. This thesis uses static analysis to find potential threats within a software's extension modules. These extensions are developed by third parties and should not be allowed to access information belonging to other extensions. However, due to the structure of the software there is no easy way to restrict this and still keep the software's functionality intact. The use of a static analysis tool could detect such threats by analyzing the code of an extension before it is published online, and therefore keep all current functionality intact. As the software is based on a lesser known language and there is a specific threat by way of information disclosure, a new static analysis tool has to be developed. To achieve this, a combination of language specific functionality and features available in C++ are combined to create an extendable tool which has the capability to detect cross-extension data access.

fulltext
• 310.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. KTH, Stockholm, Sweden. KTH, Stockholm, Sweden.
En jämförelse mellan programsamanhållande kurser vid KTH och LiU2015Ingår i: Proceedings of 5:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar (UtvSvIng), 2015Konferensbidrag (Övrigt vetenskapligt)

Programsammanhållande kurser där studenter från årskurs 1-3 gemensamt reflekterar över teman med koppling till deras studier och framtida yrkesliv finns på både KTH och Linköpings universitet (LiU). Syftet med kurserna är främst att skapa en helhet i utbildningen och ge förståelse för vad den leder till, genom att få studenterna att reflektera över sina studier och sin kommande yrkesroll. Detta leder förhoppningsvis till ökad genomströmning och minskade avhopp. Kurserna har gemensamt ursprung men har utvecklats i olika riktningar. Artikeln jämför tre programsammanhållande kurser för Datateknik KTH, Medieteknik KTH samt Data- och mjukvaruteknik Linköpings universitet.

• 311.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Återkoppling genom automaträttning2013Ingår i: Proceedings of 4:de Utvecklingskonferensen för Sveriges ingenjörsutbildningar (UtvSvIng), 2013Konferensbidrag (Refereegranskat)

Vi har undersökt olika former av återkoppling genom automaträttning i en kurs i datastrukturer och algoritmer. 2011 undersökte vi effekterna av tävlingsliknande moment som också använder automaträttning. 2012 införde vi automaträttning av laborationerna. Vi undersökte då hur återkoppling genom automaträttning påverkar studenternasarbetssätt, prestationsgrad och relation till den examinerande personalen. Genom automaträttning får studenterna omedelbar återkoppling om deras program är tillräckligt snabbt och ger rätt svar på testdata. När programmet är korrekt och resurseffektivt kontrollerar kursassistenterna att programmet även uppfyller andra krav som att vara välskrivet och välstrukturerat. Efter kursen undersökte vi studenternas inställning till och upplevelse av automaträttning genom en enkät. Resultaten är att studenterna är positiva till automaträttning (80% av alla som svarade) och att den påverkade studenternas sätt att arbeta huvudsakligen positivt. Till exempel svarade 50% att de ansträngde sig hårdare tack vare automaträttningen. Dessutom blir rättningen mer objektiv då den görs på exakt samma sätt för alla. Vår slutsats är att återkoppling genom automaträttning ger positiva effekter och upplevs som positiv av studenterna.

fulltext
• 312.
Linköpings universitet, Institutionen för datavetenskap, KPLAB - Laboratoriet för kunskapsbearbetning. Linköpings universitet, Institutionen för datavetenskap, Artificiell intelligens och integrerade datorsystem. Linköpings universitet, Tekniska fakulteten.
Programutvecklingsstrategier för att öka kopplingen mellan programmering och matematik2015Ingår i: Proceedings of 5:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar (UtvSvIng), 2015Konferensbidrag (Refereegranskat)

Matematik och programmering är två viktiga inslag i civilingenjörsprogram inom data- och mjukvaruteknik. De studenter som klarar dessa kurser klarar sannolikt resten av utbildningen. Idag har fler studenter programmering än matematik som huvudsakligt intresse. Därför har Linköpings universitet aktivt jobbat med olika strategier för att öka kopplingen mellan programmering och matematik, främst i de inledande kurserna. För att undersöka studenternas attityder till matematik och programmering har vi genomfört flera enkätstudier som bl.a. visar att intresset för matematik är stort men intresset för programmering ännu större och att studenterna tror de kommer ha betydligt mer nytta av programmering än matematik under sin karriär. Texten är tänkt som grund för en diskussion kring hur kopplingarna mellan matematik och programmering kan göras tydligare och starkare.

• 313.
A Review of Models for Introducing Computational Thinking, Computer Science and Computing in K-12 Education.2016Ingår i: Proceedings of the 46th Frontiers in Education (FIE), IEEE , 2016Konferensbidrag (Refereegranskat)

Computing is becoming ever increasingly importantto our society. However, computing in primary and secondaryeducation has not been well developed. Computing has traditionallybeen primarily a university level discipline and there areno widely accepted general standards for what computing at K–12 level entails. Also, as the interest in this area is rather new,the amount of research conducted in the field is still limited. Inthis paper we review how 10 different countries have approachedintroducing computing into their K–12 education. The countriesare Australia, England, Estonia, Finland, New Zealand, Norway,Sweden, South Korea, Poland and USA.

The studied countries either emphasize digital competenciestogether with programming or the broader subject of computingor computer science. Computational thinking is rarely mentionedexplicitly, but the ideas are often included in some form. Themost common model is to make it compulsory in primary schooland elective in secondary school. A few countries have made itcompulsory in both. While some countries have only introducedit in secondary school.

• 314.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Improving the Performance of the Eiffel Event Persistence Solution2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

Deciding which database management system (DBMS) to use has perhaps never been harder. In recent years there has been an explosive growth of new types of database management systems that address different issues and performs well for different scenarios. This thesis is an improving case study of an Event Persistence Solution for the Eiffel Framework, which is a framework used for achieving traceability in very-large-scale systems development. The purpose of this thesis is to investigate whether it is possible to improve the performance of the Eiffel Event Persistence Solution by changing from MongoDB, to Elasticsearch or ArangoDB. Experiments were conducted to measure the request throughput for 4 types of requests. As a prerequisite to measuring the performance, support for the different DBMSs and the possibility to change between them was implemented. The results showed that Elasticsearch performed better than MongoDB in terms of nested-document-search as well as for graph-traversal operations. ArangoDB had even better performance for graph-traversal operations but had an inadequate performance for nested-document-search.

fulltext
• 315.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Efficient Multi-Core Implementation of the IPsec Encapsulating Security Payload Protocol for a Single Security Association2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

fulltext
• 316.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
A Lightweight Secure Development Process for Developers2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

Following a secure development process when developing software can greatly increase the security of the software. Several secure development processes have been developed and are available for companies and organizations to adopt. However, the processes can be expensive and complex to adopt in terms of expertise, education, time, and other resources.In this thesis, a software service, developed by a small IT-consulting company, was tested with security tools and manual code review to find security vulnerabilities. These vulnerabilities showed that there was room for security improvement in the software development life cycle. Therefore, a lightweight secure development process that can be used by developers, is proposed. The secure development process called Lightweight Developer-Oriented Security Process (LDOSP) is based on activities from other secure development processes and the choice of these activities were based on interviews with representatives of the IT-consulting company. The interviews showed that the process would need to be lightweight, time- and cost-efficient, and possible to be performed by a developer without extensive security experience. LDOSP contains 11 activities spread across different phases of the software development life cycle and an exemplification of the process was made to simplify the adoption of LDOSP.

fulltext
• 317.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Automating Text Categorization with Machine Learning: Error Responsibility in a multi-layer hierarchy2017Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

The company Ericsson is taking steps towards embracing automating techniques and applying them to their product development cycle. Ericsson wants to apply machine learning techniques to automate the evaluation of a text categorization problem of error reports, or trouble reports (TRs). An excess of 100,000 TRs are handled annually.

This thesis presents two possible solutions for solving the routing problems where one technique uses traditional classifiers (Multinomial Naive Bayes and Support Vector Machines) for deciding the route through the company hierarchy where a specific TR belongs. The other solution utilizes a Convolutional Neural Network for translating the TRs into low-dimensional word vectors, or word embeddings, in order to be able to classify what group within the company should be responsible for the handling of the TR. The traditional classifiers achieve up to 83% accuracy and the Convolutional Neural Network achieve up to 71% accuracy in the task of predicting the correct class for a specific TR.

fulltext
• 318.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Naive Bayes-klassificering av förarbeteende2017Självständigt arbete på grundnivå (kandidatexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)

Att kunna klassificera en körstil implicerar klassificering av körbeteende, vilket ligger till grunden för miljö- och säkerhetsklassificering för körningar.

I det här arbetet har vi låtit två förare köra en bil med en förhoppning att kunna klassificera vem det var som körde bilen. Målet var att kunna förutspå föraren med en korrekthet på 80-90% givet endast hastighet samt varvtal som samlas genom ODB:II-porten via CAN-bussen i fordonet. Angreppsättet på detta arbete liknar det för textklassificering, nämligen att använda två vanliga klassificeringsmetoder från just textklassificering — Multinominal och Gaussisk Naive Bayes tillsammans med N-gram samt diskretisering.

Vi fann genom att använda Multinominal Naive Bayes med 4-gram samt icke-diskretiserade respektive diskretiserade hastighet- och varvtalsvärden kunde klassificera förare med 91.48% korrekthet.

fulltext
• 319.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Implementation of a real-time Fast Fourier Transform on a Graphics Processing Unit with data streamed from a high-performance digitizer2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

In this thesis we evaluate the prospects of performing real-time digital signal processing on a graphics processing unit (GPU) when linked together with a high-performance digitizer. A graphics card is acquired and an implementation developed that address issues such as transportation of data and capability of coping with the throughput of the data stream. Furthermore, it consists of an algorithm for executing consecutive fast Fourier transforms on the digitized signal together with averaging and visualization of the output spectrum.

An empirical approach has been used when researching different available options for streaming data. For better performance, an analysis of the introduced noise of using single-precision over double-precision has been performed to decide on the required precision in the context of this thesis. The choice of graphics card is based on an empirical investigation coupled with a measurement-based approach.

An implementation in single-precision with streaming from the digitizer, by means of double buffering in CPU RAM, capable of speeds up to 3.0 GB/s is presented. Measurements indicate that even higher bandwidths are possible without overflowing the GPU. Tests show that the implementation is capable of computing the spectrum for transform sizes of $2^{21}$, however measurements indicate that higher and lower transform sizes are possible. The results of the computations are visualized in real-time.

fulltext
• 320.
Univ Cote Azur, France.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Ensuring Memory Consistency in Heterogeneous Systems Based on Access Mode Declarations2018Ingår i: PROCEEDINGS 2018 INTERNATIONAL CONFERENCE ON HIGH PERFORMANCE COMPUTING and SIMULATION (HPCS), IEEE , 2018, s. 716-723Konferensbidrag (Refereegranskat)

Running a program on disjoint memory spaces requires to address memory consistency issues and to perform transfers so that the program always accesses the right data. Several approaches exist to ensure the consistency of the memory accessed, we are interested here in the verification of a declarative approach where each component of a computation is annotated with an access mode declaring which part of the memory is read or written by the component. The programming framework uses the component annotations to guarantee the validity of the memory accesses. This is the mechanism used in VectorPU, a C++ library for programming CPU-GPU heterogeneous systems and this article proves the correctness of the software cache-coherence mechanism used in the library. Beyond the scope of VectorPU, this article can be considered as a simple and effective formalisation of memory consistency mechanisms based on the explicit declaration of the effect of each component on each memory space.

• 321.
Univ Claude Bernard Lyon 1, France; Univ Cote Azur, France.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Leveraging access mode declarations in a model for memory consistency in heterogeneous systems2020Ingår i: The Journal of logical and algebraic methods in programming, ISSN 2352-2208, E-ISSN 2352-2216, Vol. 110, artikel-id UNSP 100498Artikel i tidskrift (Refereegranskat)

On a system that exposes disjoint memory spaces to the software, a program has to address memory consistency issues and perform data transfers so that it always accesses valid data. Several approaches exist to ensure the consistency of the memory accessed. Here we are interested in the verification of a declarative approach where each component of a computation is annotated with an access mode declaring which part of the memory is read or written by the component. The programming framework uses the component annotations to guarantee the validity of the memory accesses. This is the mechanism used in VectorPU, a C++ library for programming CPU-GPU heterogeneous systems. This article proves the correctness of the software cache-coherence mechanism used in VectorPU. Beyond the scope of VectorPU, this article provides a simple and effective formalization of memory consistency mechanisms based on the explicit declaration of the effect of each component on each memory space. The formalism we propose also takes into account arrays for which a single validity status is stored for the whole array; additional mechanisms for dealing with overlapping arrays are also studied. (C) 2019 Elsevier Inc. All rights reserved.

• 322.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Improving AR visualizationwith Kalman filtering andhorizon-based orientation: – To prevent boats to run aground at sea2018Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

This thesis researched the possibility of improving the compass of smartphones as theearth’s magnetic field is not strong and is easily disturbed, either by the environment ortechnology. The compass is used in Augmented Reality (AR) when the AR visualizationshould correspond to a position on earth. The issue lies in oscillating input values to thecompass that reduces the AR experience.To improve the AR experience without the use of external equipment, this work tried toboth filter the incoming values with a Kalman filter and to know the direction by capturingan image with a horizon that was image processed. The Kalman filter achieved a reductionin incoming disturbances and the horizon was matched against a panorama image thatwas generated from 3D data. The thesis starts off with requirements and contents of ARand goes through the different approaches that begins with a LAS point cloud and ends inmatching horizons with normalized cross-correlation.This thesis furthermore measures performance and battery drainage of the built applicationon three different smartphones that are nearly a year apart each. Drift was alsomeasured as it is a common issue if there is no earthly orientation to correct itself unto,for instance the magnetometer. This showed that these methods can be used on OnePlus2, Samsung Galaxy S7, and Samsung Galaxy S8, there is a steady performance and efficiencyincrease in each generation and that ARCore causes less drift. Furthermore thisthesis shows the difference between a compass and a local orientation with an offset.The application that was made focused to work at sea but it was also tested on buildingswith good results. The application also underwent usability tests that showed that theapplied functionalities improved the AR-experience. The conclusion shows that it is possibleto improve the orientation of smartphones. Albeit it can go wrong sometimes which iswhy this thesis also presents two ways to indicate that the heading is off.

fulltext
• 323.
Instituto Tecnológico de Aeronáutica (ITA), Brazil.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Combining GSN and STPA for Safety Arguments2019Ingår i: Proceedings of the 7th International workshop on Assurance Cases for Software-intensive Systems (ASSURE), held in conjunction with SAFECOMP, Springer, 2019Konferensbidrag (Refereegranskat)

Dependability case, assurance case, or safety case is employed to explain why all critical hazards have been eliminated or adequately mitigated in mission-critical and safety-critical systems. Goal Structuring Notation (GSN) is the most employed graphical notation for documenting dependability cases. System Theoretic Process Analysis (STPA) is a technique, based on System Theoretic Accidents Model and Process (STAMP), to identify hazardous control actions, scenarios, and causal factors. STPA is considered a rather complex technique, but there is a growing interest in using STPA in certifications of safety-critical systems development. We investigate how STAMP and STPA can be related to use of assurance cases. This is done in a generic way by representing the STPA steps as part of the evidence and claim documentations within GSN.

• 324.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Energy-Efficient Mobile Communication with Cached Signal Maps2016Självständigt arbete på grundnivå (kandidatexamen), 10,5 poäng / 16 hpStudentuppsats (Examensarbete)

Data communication over cellular networks is expensive for the mobile device in terms of energy, especially when the received signal strength (RSS) is low. The mobile device needs to amplify its transmission power to compensate for noise leading to an increased energy consumption. This thesis focuses on developing a RSS map for the third generation cellular technology (3G) which can be stored locally at the mobile device, and can be used for avoiding expensive communication in low RSS areas.

The proposed signal map is created by crowdsourced information collected from several mobile devices. An application is used to collect data in the mobile device of the user and the application periodically sends the information back to the server which computes the total signal map.

The signal map is composed of three levels of information: RSS information, data rate tests and estimated energy levels. The energy level categorizes the energy consumption of an area into "High", "Medium" or "Low" based on the RSS, data rate test information and an energy model developed from physical power measurements. The coarse categorization provides an estimation of the energy consumption at each location. It is evaluated by collecting data traces on a smartphone at different locations and comparing the measured energy consumption at each location to the energy level categories of the map.

The RSS prediction is preliminarily evaluated by collecting new data along a path and comparing how well it correlates to the signal map. The evaluation in this thesis shows that with the current collected data there are not enough observations in the map to properly estimate the RSS. However, we believe that with more observations a more accurate evaluation could be done.

fulltext
• 325.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Singapore University of Technology and Design (SUTD), Information Systems Technology and Design (ISTD), Singapore. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Measurement Based Execution Time Analysis of GPGPU Programs via SE+GA2018Konferensbidrag (Refereegranskat)

Understanding the execution time is critical for embedded, real-time applications. Worst-case execution time (WCET) is an important metric to check the real-time constraints imposed on embedded applications. For complex execution platforms, such as graphics processing units (GPUs), analysis of WCET imposes great challenges due to the complex characteristics of GPU architecture as well as GPU program semantics. In this paper, we propose GDivAn, a measurement-based WCET analysis tool for arbitrary GPU kernels. GDivAn systematically combines the strength of symbolic execution (SE) and genetic algorithm (GA) to maintain both the scalability and the effectiveness of the analysis process. Our evaluation with several open-source GPU kernels reveals the efficiency of GDivAn.

• 326.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Singapore University of Technology and Design (SUTD), Information Systems Technology and Design (ISTD). Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Genetic Algorithm Based Estimation of Non–Functional Properties for GPGPU Programs2020Ingår i: Journal of systems architecture, ISSN 1383-7621, E-ISSN 1873-6165, Vol. 103Artikel i tidskrift (Refereegranskat)

Non-functional properties, like execution time or memory access information, of programs running on graphics processing unit (GPUs) can raise safety and security concerns. For example, understanding the execution time is critical for embedded and real-time applications. To this end, worst-case execution time (WCET) is an important metric to check the real-time constraints imposed on embedded applications. For complex execution platforms, such as GPUs, analysis of WCET imposes great challenges due to the complex characteristics of GPU architecture as well as GPU program semantics. GPUs also have specific memory access behavior. Observing such memory access behavior may reveal sensitive information (e.g. a secret key). This, in turn, may be exploited to launch a side-channel attack on the underlying program.

In this paper, we propose GDivAn, a measurement-based analysis framework for investigating the non-functional aspects of GPU programs, specifically, their execution time and side-channel leakage capacity. GDivAn is built upon a novel instantiation of genetic algorithm (GA). Moreover, GDivAn improves the effectiveness of GA using symbolic execution, when possible. Our evaluation with several open-source GPU kernels, including GPU kernels from the OpenSSL and MRTC benchmark suite, reveals the effectiveness of GDivAn both in terms of finding WCET and side-channel leakage.

• 327.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Centre for IT-Security, Privacy and Accountability, Saarland University, Germany. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Systematic detection of memory related performance bottlenecks in GPGPU programs2016Ingår i: Journal of systems architecture, ISSN 1383-7621, E-ISSN 1873-6165, Vol. 71, s. 73-87Artikel i tidskrift (Refereegranskat)

Graphics processing units (GPUs) pose an attractive choice for designing high-performance and energy-efficient software systems. This is because GPUs are capable of executing massively parallel applications. However, the performance of GPUs is limited by the contention in memory subsystems, often resulting in substantial delays and effectively reducing the parallelism. In this paper, we propose GRAB, an automated debugger to aid the development of efficient GPU kernels. GRAB systematically detects, classifies and discovers the root causes of memory-performance bottlenecks in GPUs. We have implemented GRAB and evaluated it with several open-source GPU kernels, including two real-life case studies. We show the usage of GRAB through improvement of GPU kernels on a real NVIDIA Tegra K1 hardware – a widely used GPU for mobile and handheld devices. The guidance obtained from GRAB leads to an overall improvement of up to 64%.

• 328.
Univ Notre Dame, IN 46556 USA.
Tech Univ Brunswick, ME USA. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Univ New South Wales Sydney, Australia. Univ Calif Berkeley, CA 94720 USA. Samsung, South Korea. DENSO CORP, Japan.
Machine Learning for Embedded Systems: Hype or Lasting Impact? A Panel at ESWEEK 20172018Ingår i: IEEE design & test, ISSN 2168-2356, E-ISSN 2168-2364, Vol. 35, nr 6, s. 86-93Artikel i tidskrift (Övrigt vetenskapligt)

n/a

• 329.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Signal-Aware Route Planning2016Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)

Modern vehicles have an increasing number of advanced features requiring network coverage in order to function properly. In order to facilitate the requirements of such features and allow more advanced applications, we consider the possibility of planning routes that take signal strength into consideration. Previous work have shown the relationship between TCP throughput/goodput and signal strength. In this thesis signal-aware route planning is presented, implemented, and validated. Crowd-sourced map and signal data (3G) from two sources is used for building a signal coverage map. The signal and map data is validated in a field experiment, where routes were travelled while measuring the signal strength. The field experiment showed gains in signal characteristics when deviating from the shortest possible path. The average signal strength increased by 11 dBm between algorithms and the shortest possible path. Lastly, routes were planned for all possible sources and destinations in a given urban area. The results of this calculation confirms the patterns found in the field experiment.

fulltext
• 330.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Connectivity-optimal Shortest Paths Using Crowdsourced Data2016Ingår i: 2016 IEEE International Conference on Pervasive Computing and Communication Workshops (PerCom Workshops), IEEE Computer Society, 2016, s. 1-6Konferensbidrag (Refereegranskat)

With the increasing dependency of ubiquitous connectivity for applications ranging from multimedia entertainment to intelligent transportation systems, having good signal coverage becomes vital. Therefore, route planners and navigation systems should take into account not only the physical distance, but also the characteristics and availability of the cellular network on the potential routes. In this paper we present a route planning tool that finds the connectivity-aware shortest paths based on crowdsourced data from OpenStreetMap and OpenSignal. The tool calculates optimal paths and allows physical distance tobe traded against signal quality. The evaluation shows that a 15% increase of the physical path length can achieve an 8.7dBm improvement of worst-case signal strength.

fulltext
• 331.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Investigating Architecture Description Languages (ADLs) A Systematic Literature Review2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

Context: Over the last two decades, software architecture has introduced a new trend insoftware development. This new trend has completely changed the normal methods andpractices of software engineering. The focus has become the architectural elements ratherthan code and sub-routines. Architecture description languages (ADLs) have been proposedfor this kind of architecture based software development. There are a number of differentADLs both in academia and industry; they are not totally adopted by the software engineeringcommunity, but they are not avoided either. In this research work, an investigation has beenperformed based on the ADLs evaluation in practice.

Objectives: The main aim of this study is to investigate evaluation of ADLs in academia andindustry. To explore the benefits and drawbacks of ADLs in practice. The study also exploresthe different quality factors improved by ADLs. Further different methods used to buildarchitecture with ADLs and then how to use architecture described with an ADL in softwaredevelopment and maintenance have also been reported.

Methods: This research study has been carried out using the systematic literature reviewmethod. The systematic literature review follows the guidelines suggested by Kitchenham[21].

Conclusions: The Large number of ADLs with little evaluation in industry suggests thatmore work needs to be done in order to improve ADLs evaluation in practice. ADLs providemore benefits compared to their drawbacks which suggests that ADLs can be very beneficial.Knowledge gained during this research study, suggests that ADLs are mostly unrecognized.More awareness about ADLs should be provided in education and practice.

Systematic Literature Review of Architecture Description Languages (ADLs)
• 332.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Finding Correlation and Predicting System Behavior in Large IT Infrastructure2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

Modern IT development infrastructure has a large number of components that must be monitored, for instance servers and network components. Various system-metrics (build time, CPU utilization, queries time etc.) are gathered to monitor system performance. In practice, it is extremely difficult for a system administrator to observe a correlation between several systemmetrics and predict a target system-metric based on highly correlated system-metrics without machine learning support.

The experiments were performed on development logs at Ericsson. There were many system-metrics available in the system. Our goal is use machine learning techniques to find correlation between buildtime and other system-metrics and predict its trends in the future.

fulltext
• 333.
University of Penn, PA 19104 USA.
University of Seoul, South Korea. Korea Adv Institute Science and Technology, South Korea. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
A Process Algebraic Approach to Resource-Parameterized Timing Analysis of Automotive Software Architectures2016Ingår i: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 12, nr 2, s. 655-671Artikel i tidskrift (Refereegranskat)

Modern automotive software components are often first developed by different suppliers and then integrated under limited resources by a manufacturer. The integration of software components under various resource configurations is prone to timing errors because the components are resources independently designed by the supplier and viewed by the manufacturer as black boxes during the integration stage, so that imposing resource constraints/requirements on their behavior is a challenge. This paper introduces an engineering awareness environment for the analysis of automotive systems with respect to two perspectives: 1) time-aware design models that correspond to the supplier perspective; and 2) resource-aware design models imposed by the manufacturer during integration. To this end, first we propose two timed behavioral models, a time-constrained model (TcM) and a resource-constrained model (RcM) that are extended from a functional model (FM). A timing analysis of applications can hence be conducted incrementally by adopting the separation of concerns principle coming from the model-driven architectures (MDAs). Second, given a basic application component description of AUTomotive Open System Architecture with timing properties, we specify how to define the behavior of the basic components as process terms using a process algebra, algebra of communicating shared resources with value passing (ACSR-VP), in order to exploit the description capability of the language for both timing aspects and resource-constrained aspects of a system. As a result, a timed behavioral model of a system can be seamlessly refined by various resource configurations, and both platform-independent and platform-dependent timing properties of real-time systems can be analyzed in a consistent and efficient manner.

• 334.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Testing and Gherkin in agile projects2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

Testing in agile software development is important to ensure that the rightproduct is being developed. Is it possible to include everyone in agilesoftware development by using a business readable DSL and also createtest cases based directly on that DSL?Observations, interviews, a study of literature, third degree collectedartifacts and an implementation has been performed to analyse the processof introducing Gherkin as a tool in agile software development projects.The process of performing and conducting tests has been examined at Accedoto understand how Gherkin together with CucumberJS can be usedin projects, with the purpose of increasing collaboration between dierentroles and create a ubiquitous way of referring to the same piece of softwarewithout the need to specifying implementation details.To include the entire project team in the whole process of developingsoftware is essential for a usage of Gherkin to be successful. Since thepurpose is that everyone should be able to contribute as well as understandthe progress of development in projects and share an agreement on whatis being developed. A business readable DSL provides a uniform formatto specifying tasks causing the internal communication to be improved inprojects.

Testing and Gherkin in agile projects
• 335.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
Representing attacks in a cyber range2019Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

Trained security experts can be a mitigating factor to sophisticated cyberattacks that aim to violate the confidentiality, integrity, and availability of information. Reproducible sessions in a safe training environment is an effective way of increasing the excellence of security experts. One approach to achieving this is by using cyber ranges, which essentially is a set of hardware nodes that can virtually represent a large organization or system. The Swedish Defense Research Agency (FOI) develops and maintains a fully functioning cyber range and has the ability to automatically deploy sophisticated attacks against organizations and systems represented in this cyber range through a system called SVED.

In this thesis, the capability to deploy different types of cyberattacks through SVED against virtual organizations in a cyber range, CRATE, is investigated. This is done by building a dataset of publicly disclosed security incidents from a database and attempting to represent each of them in SVED, and subsequently instantiating these attack representations against organizations in CRATE.

The results show that the prevalence of at least one CVE-entry (Common Vulnerabilities and Exposures) in the incident description is a key factor to be able to represent an attack in SVED. When such an entry does exist, SVED is likely able to implement a representation of the attack. However, for certain type of attacks a CVE-entry is not enough to determine how an attack was carried out, which is why some attacks are harder to implement in SVED. This was the case for Denial of Service (DoS) attacks, which are too reliant on infrastructure rather than one or more vulnerabilities, and SQL injections, which are more reliant on the implementation of database access.

Finally, CRATE is able to handle almost all attacks implemented in SVED, given that the correct vulnerable application software is installed on at least one machine in one of the organizations in CRATE.

fulltext
• 336.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
A Cross-platform Picture Transfer Protocol for Linux-based Camera2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)

The Universal Serial Bus, USB, is widely used for connecting peripheral devices to a computer. Through the years devices that use USB has evolved and more and more complicated communication protocols have been developed using the USB standard. There are many different ways to set up communication between a USB device and a host computer. The USB standard does not include any security and this poses risks when designing communication over such a connection.

This thesis investigates how a USB-based picture transfer protocol can be designed between a small camera running embedded Linux and a host computer. The USB functionality in Windows and Mac OS/X operating systems are investigated. Solutions to create a secure USB communication are also investigated. One of three the methods of creating a USB connection with a USB device running embedded Linux are chosen based on the investigations. A protocol is then designed and an implementation developed. The protocol designed in the thesis uses existing USB functionality in the host computer operating systems Windows and Mac OS/X.

The designed protocol is evaluated for performance and security. The evaluation is made on an evaluation platform for the camera. The transfer speed of the protocol is measured to around 18 MB/s in an ideal environment. The designed protocol could be improved by using one of the security methods found in the investigations.

fulltext
• 337.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
A Cloud Based Platform for Big Data Science2014Självständigt arbete på avancerad nivå (masterexamen), 30 poäng / 45 hpStudentuppsats (Examensarbete)

A Cloud Based Platform for Big Data Science
• 338.
Embedded Intelligent Solutions (EIS) by Semcon AB, Linköping, Sweden.
University of Verona, Italy. University of Verona, Italy. University of Verona, Italy. University of Verona, Italy. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. University of Tokyo, Japan; Japan Scence and Technology Agency, Japan.
Time-Constraint-Aware Optimization of Assertions in Embedded Software2012Ingår i: Journal of electronic testing, ISSN 0923-8174, E-ISSN 1573-0727, Vol. 28, nr 4, s. 469-486Artikel i tidskrift (Refereegranskat)

Technology shrinking and sensitization have led to more and more transient faults in embedded systems. Transient faults are intermittent and non-predictable faults caused by external events, such as energetic particles striking the circuits. These faults do not cause permanent damages, but may affect the running applications. One way to ensure the correct execution of these embedded applications is to keep debugging and testing even after shipping of the systems, complemented with recovery/restart options. In this context, the executable assertions that have been widely used in the development process for design validation can be deployed again in the final product. In this way, the application will use the assertion to monitor itself under the actual execution and will not allow erroneous out-of-the-specification behavior to manifest themselves. This kind of software-level fault tolerance may represent a viable solution to the problem of developing commercial off-the-shelf embedded systems with dependability requirements. But software-level fault tolerance comes at a computational cost, which may affect time-constrained applications. Thus, the executable assertions shall be introduced at the best possible points in the application code, in order to satisfy timing constraints, and to maximize the error detection efficiency. We present an approach for optimization of executable assertion placement in time-constrained embedded applications for the detection of transient faults. In this work, assertions have different characteristics such as tightness, i.e., error coverage, and performance degradation. Taking into account these properties, we have developed an optimization methodology, which identifies candidate locations for assertions and selects a set of optimal assertions with the highest tightness at the lowest performance degradation. The set of selected assertions is guaranteed to respect the real-time deadlines of the embedded application. Experimental results have shown the effectiveness of the proposed approach, which provides the designer with a flexible infrastructure for the analysis of time-constrained embedded applications and transient-fault-oriented executable assertions.

• 339.
Indian Inst Technol, India.
Indian Inst Technol, India. Indian Inst Technol, India. Indian Inst Technol, India. Indian Inst Technol, India. SASTRA Deemed Univ, India. Independent Researcher, Manaus, Brazil. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Implementation of a Property Database and Thermodynamic Calculations in OpenModelica for Chemical Process Simulation2019Ingår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 58, nr 18, s. 7551-7560Artikel i tidskrift (Refereegranskat)

An attempt has been made to enhance the thermodynamic capability of the general purpose modeling and simulation environment OpenModelica. The property database ChemSep and the thermodynamic algorithms of DWSIM are made available in OpenModelica. The following three approaches, listed in the order of increasing computational efficiency, are attempted in this work: Python-C API, socket programming, and a native port. The most efficient method of native port is adopted to make available NRTL, Peng-Robinson, UNIFAC, and UNIQUAC algorithms in OpenModelica. Through several examples, OpenModelica results are compared with Aspen Plus, indicating a good match in all cases. This work is released as an open source to enhance the collaboration among chemical engineers.

• 340.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Industry Foundation Classes: A study of its requested use in Configura2015Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)

Configura Sverige AB is developing the software solutions Configura and CET Designer for companies dealing with highly configurable and complex products that also require space planning. The aim is to simplify the selling process. Configura Sverige AB has received requests from their customers to be able to read and write files according to an ISO standard called Industry Foundation Classes (IFC). IFC is an open international standard within Building Information Modeling (BIM) to exchange data between different software applications used for projects in the building industry and facility management. To assist Configura Sverige AB in a decision on how to further proceed, questions why users request IFC, how they need to work with IFC, and about possible workflows with IFC are considered in this thesis. To answer the questions, an interpretive case study method was used to view the questions from different perspectives. A qualitative approach was used to collect and analyze data, involving for example a survey among users requesting IFC and input from two different contractors requesting IFC files from these users. The results show that users have been requested by architects and contractors to supply IFC files, and a conclusion is that demands on the use of BIM and IFC within the public sector in certain countries is a major reason to these requests. The results has much focus on import and export of IFC files and on possible workflows using IFC files. With IFC files, users may be a part of a collaboration between several different disciplines within the building industry. Users need to base their work on other disciplines models, which in many cases will be the architect's IFC file. An IFC export shall only include the user's products, it will be up to another application to integrate these products in a coordination BIM. The IFC export will be used for interdisciplinary coordination, visualization and collision detection and it is important to use simple graphical representation of the products.

IFC Thesis Report
• 341.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Security-Driven Design of Real-Time Embedded Systems2015Doktorsavhandling, monografi (Övrigt vetenskapligt)

Real-time embedded systems (RTESs) have been widely used in modern society. And it is also very common to find them in safety and security critical applications, such as transportation and medical equipment. There are, usually, several constraints imposed on a RTES, for example, timing, resource, energy, and performance, which must be satisfied simultaneously. This makes the design of such systems a difficult problem.

More recently, the security of RTESs emerges as a major design concern, as more and more attacks have been reported. However, RTES security, as a parameter to be considered during the design process, has been overlooked in the past. This thesis approaches the design of secure RTESs focusing on aspects that are particularly important in the context of RTES, such as communication confidentiality and side-channel attack resistance.

Several techniques are presented in this thesis for designing secure RTESs, including hardware/software co-design techniques for communication confidentiality on distributed platforms, a global framework for secure multi-mode real-time systems, and a scheduling policy for thwarting differential power analysis attacks.

All the proposed solutions have been extensively evaluated in a large amount of experiments, including two real-life case studies, which demonstrate the efficiency of the presented techniques.

fulltext
omslag
presentationsbild
• 342.
Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Institute for Computing and Information Sciences, Radboud University Nijmegen, The Netherlands. Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Robustness Analysis of Real-Time Scheduling Against Differential Power Analysis Attacks2014Ingår i: IEEE Computer Society Annual Symposium on VLSI, IEEE Computer Society, 2014, s. 450-455Konferensbidrag (Refereegranskat)

Embedded systems (ESs) have been a prominent solution for enhancing system performance and reliability in recent years. ESs that are required to ensure functional correctness under timing constraints are referred to as real-time embedded systems (RTESs). With the emerging trend of utilizing RTESs in safety and reliability critical areas, security of RTESs, especially confidentiality of the communication, becomes of great importance. More recently, side-channel attacks (SCAs) posed serious threats to confidentiality protection mechanisms, namely, cryptographic algorithms. In this work, we present the first analytical framework for quantifying the influence of real-time scheduling policies on the robustness of secret keys against differential power analysis (DPA) attacks, one of the most popular type of SCAs. We validated the proposed concept on two representative scheduling algorithms, earliest deadline first scheduling (EDF) and rate-monotonic scheduling (RMS), via extensive experiments.

• 343.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Power-Aware Design Techniques of Secure Multimode Embedded Systems2016Ingår i: ACM Transactions on Embedded Computing Systems, ISSN 1539-9087, E-ISSN 1558-3465, Vol. 15, nr 1, s. 6-Artikel i tidskrift (Refereegranskat)

Nowadays, embedded systems have been widely used in all types of application areas, some of which belong to the safety and reliability critical domains. The functional correctness and design robustness of the embedded systems involved in such domains are crucial for the safety of personal/enterprise property or even human lives. Thereby, a holistic design procedure that considers all the important design concerns is essential. In this article, we approach embedded systems design from an integral perspective. We consider not only the classic real-time and quality of service requirements, but also the emerging security and power efficiency demands. Modern embedded systems are not any more developed for a fixed purpose, but instead designed for undertaking various processing requests. This leads to the concept of multimode embedded systems, in which the number and nature of active tasks change during runtime. Under dynamic situations, providing high performance along with various design concerns becomes a really difficult problem. Therefore, we propose a novel power-aware secure embedded systems design framework that efficiently solves the problem of runtime quality optimization with security and power constraints. The efficiency of our proposed techniques are evaluated in extensive experiments.

• 344.
Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
A Design Framework for Dynamic Embedded Systems with Security Constraints2013Ingår i: The 12th Swedish System-on-Chip Conference (SSoCC 2013), Ystad, Sweden, May 6-7, 2013 (not reviewed, not printed)., 2013Konferensbidrag (Övrigt vetenskapligt)
• 345.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Optimization of Secure Embedded Systems with Dynamic Task Sets2013Ingår i: Design, Automation & Test in Europe (DATE 2013), IEEE , 2013, s. 1765-1770Konferensbidrag (Refereegranskat)

In this paper, we approach embedded systems design from a new angle that considers not only quality of service but also security as part of the design process. Moreover, we also take into consideration the dynamic aspect of modern embedded systems in which the number and nature of active tasks are variable during run-time. In this context, providing both high quality of service and guaranteeing the required level of security becomes a difficult problem. Therefore, we propose a novel secure embedded systems design framework that efficiently solves the problem of run-time quality optimization with security constraints. Experiments demonstrate the efficiency of our proposed techniques.

• 346.
Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Performance Comparison of Simulated Annealing and Tabu Search on Block Cipher Optimization in Distributed Embedded Systems2011Ingår i: The 11th Swedish System-on-Chip Conference, Varberg, Sweden, May 2-3, 2011, 2011Konferensbidrag (Övrigt vetenskapligt)

In this paper, we consider distributed embedded systems in which privacy or confidentiality of the internal communication is critical, and present an approach to optimize cryptographic algorithms under strict timing constraints. We have developed a technique searching for the best system-affordable cryptographic protection for the messages transmitted over the internal communication bus. On account of the complexity of the problem, finding the optimal solution is only feasible for very small systems. Therefore, we formulate the technique in two efficient metaheuristics, and study their performance from extensive experiments.

• 347.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten. Radboud University Nijmegen, The Netherlands.
SPARTA: A scheduling policy for thwarting differential power analysis attacks2016Ingår i: 2016 21ST ASIA AND SOUTH PACIFIC DESIGN AUTOMATION CONFERENCE (ASP-DAC), IEEE Press, 2016, s. 667-672Konferensbidrag (Refereegranskat)

Embedded systems (ESs) have been widely used in various application domains. It is very important to design ESs that guarantee functional correctness of the system under strict timing constraints. Such systems are known as the real-time embedded systems (RTESs). More recently, RTESs started to be utilized in safety and reliability critical areas, which made the overlooked security issues, especially confidentiality of the communication, a serious problem. Differential power analysis attacks (DPAs) pose serious threats to confidentiality protection mechanisms, i.e., implementations of cryptographic algorithms, on embedded platforms. In this work, we present a scheduling policy, SPARTA, that thwarts DPAs. Theoretical guarantees and preliminary experimental results are presented to demonstrate the efficiency of the SPARTA scheduler.

• 348.
Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. University of Electronic Science and Technology of China, Chengdu.
Energy-Aware Design of Secure Multi-Mode Real-Time Embedded Systems with FPGA Co-Processors2013Ingår i: Proceedings of the 21st International conference on Real-Time Networks and Systems / [ed] Michel Auguin, Robert de Simone, Robert Davis, Emmanuel Grolleau, New York: Association for Computing Machinery (ACM), 2013, s. 109-118Konferensbidrag (Refereegranskat)

We approach the emerging area of energy efficient, secure real-time embedded systems design. Many modern embedded systems have to fulfill strict security constraints and are often required to meet stringent deadlines in different operation modes, where the number and nature of active tasks vary (dynamic task sets). In this context, the use of dynamic voltage/frequency scaling (DVFS) techniques and onboard field-programmable gate array (FPGA) co-processors offer new dimensions for energy savings and performance enhancement. We propose a novel design framework that provides the best security protection consuming the minimal energy for all operation modes of a system. Extensive experiments demonstrate the efficiency of our techniques.

• 349.
School of Computer Science and Technology, University of Electronic Science and Technology of China.
Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. School of Computer Science and Technology, University of Electronic Science and Technology of China.
Resource Allocation of Security-Critical Tasks with Statistically Guaranteed Energy Constraint2012Ingår i: International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2012), Seoul, Korea, August 19-22, 2012., IEEE , 2012, s. 330-339Konferensbidrag (Övrigt vetenskapligt)

In this paper, we are interested in resourceallocation for energy constrained and security-criticalembedded systems. Tasks in such systems need to besuccessfully executed under certain energy budget and berobust against serious security threatens. Different to formerenergy minimal scheduling problem, we introduce a newoptimization problem for a set of tasks with energyconstraint and multiple security choices. We present adynamic programming based approximation algorithm tominimize the security risk of the system while statisticallyguaranteeing energy consumption constraints for givenenergy slack ratio. The proposed algorithm is very efficientin both time and space dimensions, and achieves goodsolutions. Extensive simulations demonstrate the superiorityof our algorithm over other approaches.

• 350.
School of Computer Science and Engineering, University of Electronic Science and Technology of China, China School of Information and Software Engineering, University of Electronic Science and Technology of China, China .
Linköpings universitet, Institutionen för datavetenskap, ESLAB - Laboratoriet för inbyggda system. Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska högskolan. School of Information and Software Engineering, University of Electronic Science and Technology of China, China . Department of Computer Science and Engineering, University of Notre Dame, United States .
Energy Aware Real-Time Scheduling Policy with Guaranteed Security Protection2014Ingår i: 2014 19TH ASIA AND SOUTH PACIFIC DESIGN AUTOMATION CONFERENCE (ASP-DAC), IEEE conference proceedings, 2014, s. 317-322Konferensbidrag (Refereegranskat)

In this work, we address the emerging scheduling problem existed in the design of secure and energy-efficient real-time embedded systems. The objective is to minimize the energy consumption subject to security and schedulability constraints. Due to the complexity of the problem, we propose a dynamic programming based approximation approach to find the near-optimal solutions with respect to predefined security constraint. The proposed technique has polynomial time complexity which is about half of traditional approximation approaches. The efficiency of our algorithm is validated by extensive experiments.

45678910 301 - 350 av 715
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
• apa
• ieee
• modern-language-association-8th-edition
• vancouver
• Annat format
Fler format
Språk
• de-DE
• en-GB
• en-US
• fi-FI
• nn-NO
• nn-NB
• sv-SE
• Annat språk
Fler språk
Utmatningsformat
• html
• text
• asciidoc
• rtf
v. 2.35.10
| |