<p>För att ett fordon ska kunna bromsa, accelerera och svänga är friktion mellan däcken och vägen ett måste. Vid för mycket gaspådrag under en acceleration kan det hända att hjulen förlorar fäste och börjar spinna loss, något som leder till både försämrad kontroll över fordonet och att däcken slits ut i förtid. Traction controlsystemet förhindrar hjulen från att spinna loss och försöker maximera friktionen.</p><p>Målet med detta examensarbete är att utvärdera olika reglerprinciper samt att undersöka olika möjligheter för att reglera friktionen mellan däck och väg. Det är ett svårt reglerproblem, dels på grund av dess olinjäritet, dels på grund av det faktum att friktionen är en okänd parameter.</p><p>För att kunna undersöka olika reglermöjligheter har en modell över hjuldynamiken och en modell över drivlinan tagits fram i Matlabs simuleringsprogram Simulink. Därutöver har tre regulatorer designats: en fuzzy-regulator, en fuzzy-P-regulator och en PI-regulator. Regulatorerna utvärderades i tre tester som bland annat testade deras robusthet.</p><p>Fuzzy-regulatorn och fuzzy-P-regulatorn lyckades reglera systemet bra. PI-regulatorn gjorde däremot inte ett tillfredsställande jobb, mest på grund av dess behov av ett börvärde.</p> / <p>Traction is necessary for a vehicle to be able to brake, accelerate and turn. When pushing the accelerator pedal too hard during an acceleration, the wheel can loose traction and start spinning, which leads to a worsen vehicle control and also wears out the tyres faster. The traction control system prevents the wheels from spinning and tries to make the tyres maintain maximum traction.</p><p>The purpose of this master’s thesis is to evaluate different control methods and to investigate possible ways to control the traction. This is a difficult control problem due to its nonlinearity and the fact that the friction is an unknown parameter.</p><p>For the investigation, a model of the wheel dynamics and a model of the powertrain have been developed in Matlab’s simulation program Simulink. Furthermore, three different controllers have been designed; a fuzzy controller, a fuzzy-P controller and a PI controller. The controllers were evaluated in three test cycles that among others tested their robustness.</p><p>The fuzzy controller and the fuzzy-P controller managed to control the system very well. The PI controller, however, did not work satisfactory, mainly because of its need of a desired value.</p>

Το κυρίως αντικείμενο της διατριβής αυτής είναι ο σχεδιασμός και η ανάλυση αποκεντρωμένων τεχνικών ελέγχου για επίτευξη μέγιστης κάλυψης από κινούμενα δίκτυα αισθητήρων. Λόγω των πολλών εφαρμογών αυτών σε αποστολές σχετιζόμενες με εξερεύνηση περιοχών ενδιαφέροντος, περιβαλλοντική δειγματοληψία, φύλαξη ή ακόμα και θέματα ασφάλειας, μία μεγάλη μερίδα της επιστημονικής κοινότητας έχει στρέψει το ενδιαφέρον της στην ανάπτυξη μεθόδων για βέλτιστη (ει δυνατόν) περιβαλλοντική αντίληψη μέσω αισθητήρων από αυτόνομες ομάδες ρομποτικών συστημάτων. Τέτοιες ομάδες, συνήθως τοποθετούμενες αρχικώς στις περιοχές ενδιαφέροντος, σχεδιάζονται με στόχο τον αποκεντρωμένο έλεγχό τους, αντί ενός καθολικού εποπτικού συστήματος, με στόχο να επιτύχουν στην εκάστοτε αποστολή. Στα πρώτα στάδια της διατριβής αυτής, το πρόβλημα της κάλυψης μιας περιοχής ενδιαφέροντος από μία ομάδα όμοιων κόμβων αναλύεται από υπολογιστική σκοπιά. Οι κινούμενοι κόμβοι υποθέτονται ότι υπακούν σε απλοϊκό κινηματικό μοντέλο διακριτού χρόνου, ενώ η αισθητήρια επίδοσή τους θεωρείται ακτινική, περιορισμένης εμβέλειας, ομοιόμορφη γύρω από τον κόμβο. Σαν πρώτη προσέγγιση, η κατεύθυνση σε κάθε χρονική στιγμή για βέλτιστη κάλυψη καθορίζεται βάσει τεχνικών διαμέρισης του χώρου βασιζόμενες στην έννοια της απόστασης. Η αναπτυσσόμενη στρατηγική επιτρέπει σταδιακή αύξηση της καλυπτόμενης επιφάνειας μεταξύ διαδοχικών βημάτων, ενώ έχει ως απαίτηση την κίνηση ενός μόνο επιτρεπτού κόμβου τη φορά. Στη συνέχεια, το προαναφερθέν σχέδιο επεκτείνεται για την περίπτωση ετερογενών δικτύων, όπου η ετερογένεια αντικατοπτρίζεται στις άνισες εμβέλειες απόδοσης αίσθησης των κόμβων. Επιπροσθέτως, επέκταση σε μοντέλο συνεχούς χρόνου επιτρέπει την κίνηση όλων των κόμβων του δικτύου ταυτόχρονα, αυξάνοντας ιδιαίτερα τον χρόνο σύγκλισης προς την βέλτιστη κατάσταση, ειδικά για μεγάλης κλίμακας δίκτυα. Μία εναλλακτική διαμέριση του χώρου αναπτύσσεται, η οποία βασίζεται κυρίως στα αισθητήρια μοτίβα των κόμβων, παρά στις θέσεις των κόμβων καθεαυτές. Τα παραγόμενα κελιά του χώρου ανατιθέμενα στους κόμβους αποτελούν τον βασικό πυρήνα του αλγόριθμου οργάνωσης, με στόχο την αποκεντρωμένη οργάνωση της κινούμενης ομάδας, ώστε να επιτύχει βέλτιστη απόδοση κάλυψης. Υποκινούμενοι από την υψηλού–βαθμού ανισοτροπία που χαρακτηρίζει κάποιους τύπους αισθητήρων, όπως κατευθυντικά μικρόφωνα για ανίχνευση ήχου σε εφαρμογές ασφάλειας, ή ακόμα μοτίβα εκπομπής/λήψης κατευθυντικών κεραιών σε σενάρια τηλεπικοινωνιακής κάλυψης, η έρευνά μας επεκτείνεται πέραν του κλασσικού ακτινικού μοντέλου δίσκου αίσθησης. Βασιζόμενοι σε συγκεκριμένες ιδιότητες για επίπεδες κυρτές καμπύλες, μια αποκεντρωμένη στρατηγική οργάνωσης αναπτύχθηκε για δίκτυα που χαρακτηρίζονται από κυρτά αισθητήρια μοτίβα ίδιας κατευθυντικότητας. Παρότι η κυρτότητα των συνόλων αίσθησης φαίνεται να θέτει ένα μεγάλου βαθμού περιορισμό στο συνολικό πρόβλημα, στην πραγματικότητα προσπερνάται μέσω ανάθεσης αυτών ως το μέγιστο κυρτό χωρίο που εγγράφεται στο πρωταρχικώς ανισοτροπικό μοτίβο. Το σχήμα ελέγχου επεκτείνεται στη συνέχεια για την περίπτωση όπου εισάγουμε ένα επιπλέον βαθμό ελευθερίας στις κινηματικές ικανότητες των κόμβων, ενσωματώνοντας έτσι διαφορετικές και χρονικά μεταβαλλόμενες κατευθυντικότητες μεταξύ των μοτίβων αυτών. Το παραγόμενο πλάνο ελέγχου αποδεικνύεται ότι οδηγεί ανισοτροπικά δίκτυα σε βέλτιστες τοπολογίες, αναφορικά με τα αισθητήρια μοτίβα τους, ελέγχοντας κατάλληλα ταυτόχρονα την θέση και προσανατολισμό, μέσω ενός καινοτόμου σχήματος κατακερματισμού του χώρου βασιζόμενο στο εκάστοτε μοτίβο. Η διατριβή κλείνει με την μελέτη δικτύων με περιορισμούς στην εμβέλεια επικοινωνίας αναφορικά με την μετάδοση πληροφοριών μεταξύ των κόμβων. Στην πλειονότητα των σχετικών εργασιών, το ζήτημα αυτό προσπερνάται επιτρέποντας στην εμβέλεια επικοινωνίας να είναι τουλάχιστον διπλάσια αυτής της (ομοιόμορφης) αίσθησης, εγγυώντας έτσι την αποκεντρωμένη φύση των πλάνων ελέγχου. Ο προτεινόμενος έλεγχος επιτρέπει την αποσύζευξη μεταξύ των δύο αυτών εμβελειών, οδηγώντας το δίκτυο στην βέλτιστη κατάσταση, μέσω ταυτόχρονου σεβασμού του εκάστοτε, εκ των προτέρων δοσμένου, περιορισμού στην εμβέλεια επικοινωνίας. Συγκεντρωτικά συμπεράσματα και συγκριτική ανάλυση παρουσιάζονται στο τελευταίο κεφάλαιο, ενώ προτείνονται μελλοντικά πλάνα επέκτασης των τεχνικών αυτών. / The main scope of this thesis is the design and analysis of distributed control strategies for achieving optimum area coverage in mobile sensor networks. Due to the numerous applications of the latter in missions as area exploration, environmental sampling, patrolling, or even security, a large part of the scientific community has turned its interest on developing methods for achieving optimum, if possible, sensing environmental perception by groups of autonomous mobile agents. Such robotic teams, randomly deployed in areas of interest initially, are designed to coordinate their motion in a distributed manner, rather than via a global supervisory system, in order to succeed in the corresponding mission objective. At the first stages of this thesis, the coverage problem of an area of interest by a group of identical nodes is examined from a numerical point of view. The mobile nodes are considered to be governed by simple discrete–time kinodynamic motion, while their sensing performance is assumed radial, range–limited, uniform around the node. As a first approach, the optimum direction at each time step for optimum deployment achievement is determined based on proper distance–based space partitioning techniques. The developed concept allows for gradual increase in the covered area among consecutive steps, although suffers from allowing motion of one node at a time. In the sequel, the aforementioned concept is extended to the case of heterogeneous networks, where heterogeneity lays mainly in the unequal limited–range of the sensing performance of the nodes. In addition, extension to continuous–time allows for simultaneous motion of the nodes, increasing drastically the convergence time towards the optimal state, especially for large–scale networks. An alternate partitioning of the space is developed that is mainly based on the nodes’ footprints, rather than their spatial positions only. The resulting assigned cells form the main core for the coordination algorithm proposed, in order to distributedly organize the mobile swarm to achieve optimum sensing performance. Motivated by the high–degree anisotropy that governs the sensing domains of certain types of sensors, i.e. directional microphones for sound sensing mainly for security applications, or even the radiation patterns of directional antennas in communication–coverage scenarios, our research is extended beyond the standard disc model of sensing. Based on certain properties for planar convex curves, a distributed strategy is developed for networks characterized by convex sensing domains of same orientation. Although convexity of the sensing sets may seem to impose a high level restriction to the overall setup, in fact can be assigned as the maximal convex inscribed set in any (originally) anisotropic pattern. The control scheme is further extended, in the sequel, for the case of adding an extra degree of freedom to the node’s mobility abilities, incorporating different and time–varying orientations among the nodes patterns. The resulting scheme is proven to lead anisotropic networks in optimum configurations, considering their sensing footprints, by properly controlling both the nodes’ positions and orientations, via an innovative pattern–based partitioning scheme of the sensed space. The thesis ends by examining the case where radio–range constraints are imposed on inter–agents communication. In the majority of the related works, this issues is usually overcome by allowing RF range as double the sensing one, guaranteeing that way distributed nature of the control schemes. The proposed scheme allows for uncorrelated RF and sensing ranges in the network, while guarantees convergence of the network towards the optimal state, via simultaneous preservation of a–priori imposed radio–range constraints. Concluding remarks along with comparative discussion are presented in the last chapter, where future research plans and ways to improve the already developed schemes are proposed.

Ο σκοπός αυτής της διπλωματικής εργασίας είναι να συζητηθούν και να παρουσιαστούν οι υπάρχουσες τεχνικές που εφαρμόζουν την στρατηγική δειγματοληψίας βασισμένη σε γεγονότα για την εκτίμηση της κατάστασης των γραμμικών συστημάτων και να αξιολογηθεί πώς αυτές οι μέθοδοι επηρεάζουν τη συνολική απόδοση του συστήματος. Όπως ήδη αναφέρθηκε, περιορισμοί στον ρυθμό δειγματοληψίας ανακύπτουν στα NCS λόγω του περιορισμένου διαθέσιμου εύρους ζώνης. Αυτός ο περιορισμός στον αριθμό δειγμάτων επηρεάζει σαφώς το μέσο τετραγωνικό σφάλμα εκτίμησης, και η ερώτηση είναι πώς πρέπει να επιλέξουμε τις χρονικές στιγμές δειγματοληψίας προκειμένου να το ελαχιστοποιήσουμε. / The aim of this diploma thesis is to discuss and present existing techniques that apply event-triggered sampling to linear system state estimation, and to evaluate how these methods affect the overall performance of the system. As already mentioned, sampling rate constraints arise in NCS due to the limited bandwidth available. This restriction on the number of samples clearly affects the mean square estimation distortion error, and the question is how we should choose the sampling instants in order to minimize it.

Scriptie Hanzehogeschool Groningen. / Datum laatste controle: 04-09-2007. In opdracht van het Deventer Ziekenhuis. Met lit.opg.

<p>I denna avhandling studeras optimal återkopplad styrning av olinjära deskriptorsystem. Ett deskriptorsystem är en matematisk beskrivning som kan innehålla både differentialekvationer och algebraiska ekvationer. En av anledningarna till intresset för denna klass av system är att objekt-orienterade modelleringsverktyg ger systembeskrivningar på denna form. Här kommer det att antas att det, åtminstone lokalt, är möjligt att eliminera de algebraiska ekvationerna och få ett system på tillståndsform. Teoretiskt är detta inte så inskränkande för genom att använda någon indexreduktionsmetod kan ganska generella deskriptor\-system skrivas om så att de uppfyller detta antagande.</p><p>För system på tillståndsform kan Hamilton-Jacobi-Bellman-ekvationen användas för att bestämma den optimala återkopplingen. Ett liknande resultat finns för deskriptor\-system där istället en Hamilton-Jacobi-Bellman-liknande ekvation ska lösas. Denna ekvation innehåller dock en extra term för att hantera de algebraiska ekvationerna. Eftersom antagandena i denna avhandling gör det möjligt att skriva om deskriptorsystemet som ett tillståndssystem, undersöks hur denna extra term måste väljas för att båda ekvationerna ska få samma lösning.</p><p>Ett problem med att beräkna den optimala återkopplingen med hjälp av Hamilton-Jacobi-Bellman-ekvationen är att det leder till att en olinjär partiell differentialekvation ska lösas. Generellt har denna ekvation ingen explicit lösning. Ett lättare problem är att beräkna en lokal optimal återkoppling. För analytiska system på tillståndsform löstes detta problem på 1960-talet och den optimala lösningen beskrivs av serieutvecklingar. I denna avhandling generaliseras detta resultat så att även deskriptor-system kan hanteras. Metoden illustreras med ett exempel som beskriver en faslåsande krets.</p><p>I många situationer vill man veta om ett område är möjligt att nå genom att styra på något sätt. För linjära tidsinvarianta system fås denna information från styrbarhetgramianen. För olinjära system används istället styrbarhetsfunktionen. Tre olika metoder för att beräkna styrbarhetsfunktionen har härletts i denna avhandling. De framtagna metoderna är också applicerade på några exempel för att visa beräkningsstegen.</p><p>Dessutom har observerbarhetsfunktionen studerats. Observerbarhetsfunktionen visar hur mycket utsignalenergi ett visst initial tillstånd svarar mot. Ett par olika metoder för att beräkna observerbarhetsfunktionen för deskriptorsystem tagits fram. För att beskriva en av metoderna, studeras ett litet exempel bestående av en elektrisk krets.</p> / <p>In this thesis, optimal feedback control for nonlinear descriptor systems is studied. A descriptor system is a mathematical description that can include both differential and algebraic equations. One of the reasons for the interest in this class of systems is that several modern object-oriented modeling tools yield system descriptions in this form. Here, it is assumed that it is possible to rewrite the descriptor system as a state-space system, at least locally. In theory, this assumption is not very restrictive because index reduction techniques can be used to rewrite rather general descriptor systems to satisfy this assumption.</p><p>The Hamilton-Jacobi-Bellman equation can be used to calculate the optimal feedback control for systems in state-space form. For descriptor systems, a similar result exists where a Hamilton-Jacobi-Bellman-like equation is solved. This equation includes an extra term in order to incorporate the algebraic equations. Since the assumptions made here make it possible to rewrite the descriptor system in state-space form, it is investigated how the extra term must be chosen in order to obtain the same solution from the different equations.</p><p>A problem when computing the optimal feedback law using the Hamilton-Jacobi-Bellman equation is that it involves solving a nonlinear partial differential equation. Often, this equation cannot be solved explicitly. An easier problem is to compute a locally optimal feedback law. This problem was solved in the 1960's for analytical systems in state-space form and the optimal solution is described using power series. In this thesis, this result is extended to also incorporate descriptor systems and it is applied to a phase-locked loop circuit.</p><p>In many situations, it is interesting to know if a certain region is reachable using some control signal. For linear time-invariant state-space systems, this information is given by the controllability gramian. For nonlinear state-space systems, the controllabilty function is used instead. Three methods for calculating the controllability function for descriptor systems are derived in this thesis. These methods are also applied to some examples in order to illustrate the computational steps.</p><p>Furthermore, the observability function is studied. This function reflects the amount of output energy a certain initial state corresponds to. Two methods for calculating the observability function for descriptor systems are derived. To describe one of the methods, a small example consisting of an electrical circuit is studied.</p> / Report code: LiU-TEK-LIC-2006:8

<p>This thesis studies the accounting and auditing approach to control where the concept of internal control has developed along with the theory and practice of accounting and auditing and its stated objectives. In this context, internal control has traditionally been regarded as a means of ensuring financial reporting quality as well as a way of preventing and detecting fraudulent activity.</p><p>We have surveyed scientific research on the subject of internal control and reviewed regulatory texts as well as practical frameworks and standards. Based on this literature study, we have investigated some of the findings from previous research. Components and particular features of internal control were described and discussed. We have also identified and summarized themes and issues that frequently occur in writings on the subject.</p><p>During recent years, demands have been made for greater accountability and transparency in corporate governance. The independent audit activity has become the primary tool for securing accountability. Some regard this as the emergence of an audit society. An important joint development has been the rise of internal control systems. Internal control, once a private matter for technical assurance specialists, has risen to be an autonomous field of expertise and a mode of organizing uncertainty. Traditionally internal control has had a fairly direct relationship to the accounting records. The wider approaches to internal control have expanded its boundaries significantly, far beyond the financial reports and the duties of the accountant. Internal control has become an all-encompassing process.</p><p>Enterprise risk management practices are growing and evolving. An associated development has been that internal control has become more closely tied to these risk management practices, and therefore also to the formulation and execution of strategies. New risk-related regulations and practical frameworks have contributed to the transformation of internal control into a co-extensive with risk management. Internal control is now considered to be a form of risk treatment through which risk may be managed in different ways.</p><p>Internal control is today a primary regulatory and formal olicy object. Lawmakers and supervisory authorities are increasingly concerned with the design and operating effectiveness of internal controls. Disclosure requirements imposed on firms are forcing them to provide public disclosures about their internal control systems, which were previously private to firms.</p><p>Both scientific research and practical writings suggest that internal control designs are contingent upon certain variables. These variables include company objectives and strategies, regulatory characteristics, risk and risk appetite, firm size and managements’ attitudes to risk and control. Building internal control capabilities is important if firms are to be able to design balanced, integrated, dynamic and cost-effective internal controls.</p><p>Internal control is considered to be a key corporate governance mechanism. Some researchers however, have pointed out that there is still much to learn about internal control quality and how internal control is associated with corporate governance quality. The fact that internal control is an inherently complex concept poses a significant research barrier, and while all research methods are valid, it is unlikely that archival studies or experiments are able to measure internal control quality. Instead, we recommend case studies of how firms design, apply and oversee their systems of internal control.</p><p>This study was made possible through the research collaboration between my former employer, Skandia, and Linköping University through the Research Programme for Auditors and Consultants. During the final stage, generous funding was provided by the Jan Wallanders and Tom Hedelius foundation as well as the Tore Browaldhs foundation.</p> / <p>Denna avhandling behandlar kontroll med utgångspunkt i ett revisionsperspektiv. I detta sammanhang har begreppet intern kontroll utvecklats tillsammans med revisionens teori och praktik samt dess uppsatta målsättningar. Traditionellt har intern kontroll betraktats som ett medel för att öka effektiviteten i revisionsinsatsen och ett sätt för företagen att undvika oegentligheter samt felaktigheter i redovisning.</p><p>Inom ramen för denna studie har vi undersökt befintlig vetenskaplig forskning om intern kontroll. Vi har även tagit del av regulatoriska texter samt praktiskt orienterade ramverk och standarder avseende intern kontroll. Baserat på denna litteraturstudie har vi analyserat några av de resultat som forskning så långt har kommit fram till. Begreppets olika komponenter och aspekter har beskrivits och diskuterats. Även återkommande teman och diskussioner inom befintlig forskning om intern kontroll har identifierats och sammanfattats.</p><p>Under senare år har det framförts krav på tydligare ansvar och transparens i ägar- och bolagsstyrning. Den oberoende revisionsaktiviteten har blivit ett huvudsakligt verktyg för att säkra sådant ansvar och forskare har benämnt denna ökning av revisionsaktivitet i termer av ett revisionssamhälle. En viktig sammanhängande del i denna utveckling har varit den interna kontrollens framväxt. Intern kontroll, ett begrepp som under lång tid främst varit av intresse för revisorer, har vuxit fram till ett självständigt område och ett sätt att hantera osäkerhet. Traditionellt har intern kontroll haft ett relativt direkt förhållande till redovisning och finansiell rapportering. Bredare definitioner av intern kontroll har väsentligt utvidgat dess gränser, långt bortom de finansiella rapporterna och redovisarens uppgifter. Intern kontroll har blivit en genomgripande process i företag.</p><p>Processer för riskhantering växer och utvecklas inom företag. Som en del av denna utveckling har intern kontroll blivit knuten allt närmare till riskhantering, och därmed även till företagets mål och strategier. Nya regelverk och praktiska ramverk kring riskhantering har bidragit till att intern kontroll omformats till en förlängning av riskhantering. Intern kontroll ses idag som en form av riskrespons genom vilken företagets riskexponering kan hanteras på olika sätt.</p><p>Idag är intern kontroll ett regulatoriskt objekt. Lagstiftare, normgivare och tillsynsmyndigheter är allt mer intresserad av den interna kontrollens utformning och effektivitet. Olika regelverk ställer krav på att företag redovisar för externa intressenter hur kontrollsystemet är utformat och fungerar, kontrollsystem som tidigare varit en privat angelägenhet för företag.</p><p>Såväl forskning som praktiskt orienterad litteratur om intern kontroll menar att det interna kontrollsystemets utformning är beroende av externa och interna variabler. Dessa variabler inkluderar bolagets mål och strategier, regulatoriska förhållanden, grad av osäkerhet i omgivningen, företagsstorlek, styrelsens riskaptit samt ledningens inställning till risk och kontroll. Att utveckla kompetens inom intern kontroll är viktigt om bolag skall kunna utforma balanserade, integrerade, dynamiska och kostnadseffektiva kontroller.</p><p>Intern kontroll beskrivs idag som en viktig mekanism i ägar- och bolagsstyrning. Vissa forskare hävdar dock att det fortsatt finns mycket att lära om kvalitet i intern kontroll samt hur detta i sin tur påverkar kvaliteten i ägar- och bolagsstyrningen. Det faktum att intern kontroll är en komplex process påverkar möjligheterna att utföra forskning inom området, och även om alla forskningsmetoder är viktiga, är det osannolikt att man via arkivstudier eller experiment kan fånga komplexiteten i begreppet. Istället rekommenderar vi fallstudier av hur bolag utformar, tillämpar och följer upp intern kontroll.</p><p>Denna forskningsstudie har kunnat genomföras tack vara samarbetet mellan min tidigare arbetsgivare, Skandia, och Linköpings Universitet via Forskningsprogrammet för Revisorer och Konsulter. I slutfasen av detta projekt har även Jan Wallanders och Tom Hedelius stiftelse samt Tore Browaldhs stiftelse bidragit med generös finansiering.</p>

Background. Detecting malware command and control infrastructure has impor-tant applications for protecting against attacks. Much research has focused on thisproblem, but a majority of this research has used traffic monitoring methods fordetection. Objectives. In this thesis we explore methods based on network scanning and active probing, where detection is possible before an attack has begun, in theory resulting in the ability to bring the command and control server down preemptively. Methods. We use network scanning to discover open ports which are then fed into our probing tool for protocol identification and data gathering. Fingerprinting is performed on the open ports and running services of each host.We develop two methods for fingerprinting and classification of hosts. The first method uses a machine learning algorithm over the open ports and probe data, while the other computes distance scores between hosts. We compare these methods to the new but established JARM method for host fingerprinting, as well as to two other simple methods. Results. Our findings suggest that our general active probing method is feasible for use in detecting command and control infrastructure, but that the results vary strongly depending on the malware family, with certain malware families providing much better results than others. Conclusions. We end with discussions on the limitations of our methods and how they can be improved, as well as bring up our opinions on the potential for future work in this area. / Bakgrund. Att kunna upptäcka command-and-control-infrastruktur kopplad till malware har viktiga tillämpningar för syftet att skydda mot attacker. Mycket forskning existerar som fokuserar på detta problem, men en majoritet använder metoder baserade på trafikmonitorering. Syfte. I denna uppsats utforskar vi istället metoder baserade på scanning och probing av nätverk, genom vilka detektering är möjlig innan en attack har ägt rum, med fördelen att en command-and-control-server i teorin kan tas ner förebyggande. Metod. Vi använder nätverks-scanning för att upptäcka öppna portar vilka matas in i vårt probing-verktyg som sedan utför protokoll-identifiering och datainsamling. Vi skapar ett fingeravtryck av varje server från de öppna portarna och de hostade tjänsterna. Två metoder för klassifiering av servrar togs fram. Den första metoden använder en maskininlärningsalgoritm över de öppna portarna och probe-datan, medan den andra beräknar en distans mellan två servrar. Vi jämför dessa metoder med den nya men etablerade JARM-metoden, som tar fram fingeravtryck av servrar från TLS-data, samt med två andra, simplare metoder. Resultat. Våra upptäckter visar att vår metod, som bygger på generell, aktiv probing är möjlig att använda för detektering av command-and-control-infrastruktur, men att resultaten varierar kraftigt beroende på malware-familj, där vissa familjer erbjuder mycket bättre resultat än andra. Slutsatser. Vi avslutar med att diskutera begränsningar i våra metoder och hur dessa kan förbättras, samt tar upp våra åsikter om potentialen för framtida forskning inom detta område.

The Anti-Submarine Warfare (ASW) community requires a fully operational Command, Control, Communications, Computers, and Intelligence (C4I) architecture to significantly reduce time from sensor detection to defensive weapons release. The United States Navy has established programs of record leveraging space, terrestrial, and maritime communications capabilities extending to fiscal year 2015. An ordered systems engineering process was performed to derive requirements and identify Joint ASW C4I Architecture strengths and weaknesses. This architecture is dependent upon the ASW community’s ability to leverage current and planned technologies impacting C4I areas including common operational tactical picture delivery, data transmission rate, time latency, and data fusion processes. Performance forecasts for identified alternatives were modeled and simulated based on a synthesized operational scenario using the EXTEND simulation tool, and life cycle cost estimates were produced for each alternative. Based on those outcomes, one of the several alternatives is recommended for implementation. In addition, it was discovered that programmed C4I capabilities lack an integrated fielding plan and do not properly align in FY2020. Furthermore, the ASW community must make process changes to enable cross-program manager collaboration supported by a single system architect to ensure robust architectures are fielded by 2020.

Användandet av solceller ökar kontinuerligt i Sverige och effekten som genererasav solcellerna förvaras oftast i bly-syra batterier. Dessa batterier har en dåligpåverkan på miljön eftersom det krävs mycket energi och miljöfarliga material såsom bly och svavelsyra för att tillverka dessa batterier. Östersjökompaniet AB ochmånga av dess kunder inser vikten av ett hållbart tänkande och var intresseradeav att veta om det var möjligt att maximera livslängden av dessa batterier. Underarbetets gång analyserades olika metoder för upp- och urladdning av batterier somkan påverka ett batteris livslängd och hur man kan bära sig åt för att optimera det.En laddningskontroller användes för att optimera laddningen av batteriet. För attberäkna laddningsnivån i batteriet användes metoden ”Extended voltmeter”. Enprototyp som kunde ladda batterierna på ett optimalt sätt, varna då batterietsladdningsnivå blev för låg samt en användarvänlig applikation för övervakning avbatteriet konstruerades. Ett batteris beräknade livslängd är ingen exakt vetenskap.Enligt studier kan livslängden av ett batteri fördubblas om det laddas upp ochladdas ur på ett optimalt sätt i jämförelse med då det laddas ur helt. / The use of solar cells is continuously increasing in Sweden and the powergenerated by the solar cells is usually stored in lead acid batteries. These batterieshave a bad impact on the environment as much energy and environmentallyhazardous materials like lead and sulfuric acid are required to manufacture thesebatteries. Östersjökompaniet AB and many of its customers realize the importanceof sustainable thinking and were interested in knowing if it was possible tomaximize the lifetime of these batteries. During the course of the work, differentmethods of battery charging and discharging were analyzed that could affect thebatteries lifetime and how to take care of them to optimize them. A chargecontroller was used to optimize the charge of the battery. To calculate theremaining state of charge in the battery, the Extended voltmeter method was used.A prototype that was able to charge the batteries optimally, warn when the batterycapacity became too low, and a user-friendly application for battery monitoring wasdesigned. The calculated lifetime of a battery is not an exact science. According tostudies the lifetime of a battery can be doubled if it is c

Diss. (sammanfattning) Stockholm : Kungliga Tekniska högskolan, 2007. / Härtill 7 uppsatser.