Er Norge på vei inn i en boligboble? : en empirisk studie av det norske boligmarkedet

Denne utredningen har som formål å undersøke om Norge er på vei inn i en boligboble. Som grunnleggende teori har vi benyttet oss av kriseteori utarbeidet av Minsky og Kindleberger, samt klassisk bobleteori. Vi ønsker først å gi leser en innføring i det norske boligmarkedet ved å presentere den historiske prisutviklingen tilbake til 1819. For å se om det norske boligmarkedet er i likevekt diskuterer vi, med bakgrunn i Jacobsen og Naug (2004), hvorvidt prisutviklingen kan støttes av fundamentale forhold i økonomien. Her argumenter vi for at de høye boligprisene kan forklares, men ikke nødvendigvis støttes på lang sikt. Vår empiriske analyse følger Minsky og Kindlebergers teorier om at et etterspørselssjokk og deretter økt penge –og kredittmengde gir forløp til finansielle bobler. For å undersøke om boligprisene er overvurderte og dermed gir indikasjoner på en boble har vi analysert avvik fra trend gjennom log-lineær trend og HP-filter, samt avvik fra fundamentale verdier gjennom en Price/Rent analyse. Vi argumenterer for at lave renter og økt kredittmengde har ført til høy vekst i boligprisene og dermed høye positive avvik fra trend og fundamentale verdier. For å besvare vår problemstilling på best mulig grunnlag har vi også valgt å sammenligne utviklingen i boligprisene med kostnadene ved å bygge bolig. Vi finner at utviklingen ikke har korrelert den seneste tiden. Deretter argumenterer vi, med bakgrunn i en selvlaget spørreundersøkelse, for at markedets høye forventninger om prisstigning har ført til økte boligpriser. Avslutningsvis diskuterer vi det norske boligmarkedet i lys av Case & Shillers syv kriterier for boligboble. Vi argumenterer for at samtlige syv kriterier mer eller mindre er tilstede i det norske boligmarkedet. Med bakgrunn i analyser og drøftelser finner vi grunn til å argumentere for at Norge kan være på vei inn i en boligboble

Online Testing of Real-Time Systems Using UPPAAL: Status and Future Work

We present TUPPAAL --- a new tool for online black-box testing of real-time embedded systems from non-deterministic timed automata specifications. We describe a sound and complete randomized online testing algorithm, and describe how to implement it using symbolic state representation and manipulation techniques. We propose the notion of relativized timed input/output conformance as the formal implementation relation. A novelty of this relation and our testing algorithm is that they explicitly take environment assumptions into account, generate, execute and verify the result online using the UPPAAL on-the-fly model-checking tool engine. A medium size case study shows promising results in terms of error detection capability and computation performance

Anomaly detection in computer networks using hierarchically organized teams of learning automata

With the increasing number of computer systems connected to the Internet, security becomes a critical issue. To combat this problem, several attack detection methods have emerged in the past years, such as the rule based Intrusion Detection System (IDS) Snort - or anomaly based alternatives that are able to detect novel attacks without any prior knowledge about them. Most current anomaly based IDS require labeled attacks or extensively filtered training data, such that certain attack types, which generate large amounts of noise in terms of false positives, are effectively removed. This thesis describes a novel anomaly based scheme for detecting attacks, using frequent itemset mining, without performing extensive filtering of the input data. In brief, the scheme, which is named the Grimstad Data Classifier (GRIDAC), uses teams of hierarchically organized Learning Automata to generate a rule tree with a set of linked nodes – where the granularity of each node increases along with the current level in the tree. In turn, GRIDAC was implemented as an anomaly based IDS called Inspectobot, and evaluated using the 1999 DARPA IDS Evaluation Sets. At best, the prototype was able to detect 51 out of 62 attacks in the 1999 DARPA IDS Evaluation Sets with 56 false alarms, giving a detection rate of 82 %, after training on one week of attack-free traffic, and classifying another full week of data containing attacks. The empirical results are quite conclusive, demonstrating that the prototype shows an excellent ability to mine frequent itemsets from network packets, such that normal behavior can be modeled. With an average detection rate of 73 % of all attacks in the DARPA set, and a fairly low amount of false positives, it is also shown that Inspectobot can be used for IDS purposes. In its current state, Inspectobot requires a high processing capacity to perform the rule matching. When compared to the popular IDS Snort, it is currently not as useful outside of a testbed environment. Nonetheless, the scheme has the potential of serving as a complementary anomaly based IDS alongside Snort for detecting novel attacks, given a more optimized implementation

Online On-the-Fly Testing of Real-time Systems

In this paper we present a framework, an algorithm and a new tool for online testing of real-time systems based on symbolic techniques used in UPPAAL model checker. We extend UPPAAL timed automata network model to a test specification which is used to generate test primitives and to check the correctness of system responses including the timing aspects. We use timed trace inclusion as a conformance relation between system and specification to draw a test verdict. The test generation and execution algorithm is implemented as an extension to UPPAAL and experiments carried out to examine the correctness and performance of the tool. The experiment results are promising

Online On-the-Fly Testing of Real-time Systems

In this paper we present a framework, an algorithm and a new tool for online testing of real-time systems based on symbolic techniques used in UPPAAL model checker. We extend UPPAAL timed automata network model to a test specification which is used to generate test primitives and to check the correctness of system responses including the timing aspects. We use timed trace inclusion as a conformance relation between system and specification to draw a test verdict. The test generation and execution algorithm is implemented as an extension to UPPAAL and experiments carried out to examine the correctness and performance of the tool. The experiment results are promising

A multi-mode imager

Conventionally, the acquisition of bright-field images and fluorescence images using the same device has required an imager equipped with a mechanical movement, able to mechanically interchange filters in-between a sample stage and an imaging element, dependent on whether a bright-field or a fluorescence exposure is being made. The present application discusses a multi-mode imager (30) comprising a bright-field light source (32) and a first excitation light source (34) for exciting fluorescent dyes in a biopsy sample (31). An optical filter arrangement (36, 36a, 36b, 36c) is provided enabling the multi-mode scanning of the biopsy without the need to use a mechanism for interchanging filters