The motivation for this work is based on two recognized research issues for digital libraries. One is the need for interlinked and semantically rich information spaces where relationship information is of particular importance. The other is the serviceoriented architecture of digital libraries. The digital libraries of the future will consist of smaller and independent systems that each will provide different functionality and access to different contents. This work defines and explores a service for managing and using explicit relationships – the Digital Library Link Service. The service implements an instance-oriented approach to relationships that enables any kind of typed relationship to be created among the information objects of digital libraries. The service can be used to create consistent information spaces on top of digital library repositories and enables an associative organization and retrieval of information objects. This work shows that the use of a fine-grained relationship model implemented as distributed objects enables distribution of the relationship network while still being able to support constraints and maintain consistency. The cost of this, however, is a complexity that can reduce performance and scalability due to the call latency of network communication. A prototype is developed that utilizes caching in order to solve this. Tests conducted show that this technique significantly contributes to the scalability and efficiency. This is particularly important when the relationship information is distributed across different processes with high calllatency in between. The work further presents a prototype application for enhancing bibliographic catalogues with the rich set of relationship types defined in the bibliographic information model proposed by the International Federation of Library Associations and Institutions – the FRBR model. The Digital Library Link Service is used to implement an index that facilitates the navigation of bibliographic relationships in order to explore bibliographic entities along the paths laid out by the FRBR model. This demonstrates the applicability of the service as a flexible tool for associative organization of information objects. The main applications of the service are limited to systems with a relaxed requirement in terms of automatic processing of larger sets of relationships. The main access paradigm explored for interacting with relationships is by navigation. The need for automatic and efficient processing of a large relationship network, e.g. for the purpose of indexing, can be supported by extending the system with additional functionality. Another recognized problem is that the use of CORBA references to address long-term persistent information can cause referential integrity problems. One possible way to solve this is to assigning objects globally unique identifiers that later can be used to recover from referential integrity problems.

<p>The progression of technical development has yielded practicable camera systems for the acquisition of so called depth maps, images with depth information. </p><p>Images and movies with depth information open the door for new types of applications in the area of computer graphics and vision. That implies that they will need to be processed in all increasing volumes.</p><p>Increased depth image processing puts forth the demand for a standardized data format for the exchange of image data with depth information, both still and animated. Software to convert acquired depth data to such videoformats is highly necessary. </p><p>This diploma thesis sheds light on many of the issues that come with this new task group. It spans from data acquisition over readily available software for the data encoding to possible future applications. </p><p>Further, a software architecture fulfilling all of the mentioned demands is presented. </p><p>The encoder is comprised of a collection of UNIX programs that generate MPEG Z/Alpha, an MPEG2 based video format. MPEG Z/Alpha contains beside MPEG2's standard data streams one extra data stream to store image depth information (and transparency). </p><p>The decoder suite, called TexMPEG, is a C library for the in-memory decompression of MPEG Z/Alpha. Much effort has been put into video decoder parallelization, and TexMPEG is now capable of decoding multiple video streams, not only in parallel internally, but also with inherent frame synchronization between parallely decoded MPEG videos.</p>

<p>With the 1999 introduction of IEEE 802.11b, the 2.4 GHz Wireless Local Area Network (WLAN) standard, the WLAN market finally began to experience the growth levels that had been expected for so long. Now, 5 GHz solutions, with the IEEE 802.11a standard leading the way, offer higher throughput and more efficient use of the spectrum. Just as the 2.4 GHz band, the 5 GHz band is unlicensed. A common concern to all unlicensed bands is interference between devices using the spectrum. Furthermore, in the 5 GHz band, WLAN cells can interfere with radar systems operating at the same frequencies. </p><p>This report describes a software model, WOK, suitable for simulations of IEEE 802.11a WLANs operating in various environments and under various ambient conditions. The WOK model can be configured extensively with respect to topology, traffic behavior, channel models, signal attenuation, interference sources and radar systems. </p><p>Further, the concepts of Dynamic Frequency Selection (DFS) and link adaptation are explored in the context of the IEEE 802.11a standard. DFS aims to avoid channels occupied by radar systems and link adaptation aims to maximize the throughput based on current ambient conditions. A DFS algorithm and a link adaptation algorithm are implemented at the Medium Access Control (MAC) layer and evaluated using the WOK model.</p>

<p>The usage of automatic fingerprint identification systems as a means of identification and/or verification have increased substantially during the last couple of years. It is well known that small deviations may occur within a fingerprint over time, a problem referred to as template ageing. This problem, and other reasons for deviations between two images of the same fingerprint, complicates the identification/verification process, since distinct features may appear somewhat different in the two images that are matched. Commonly used to try and minimise this type of problem are different kinds of fingerprint image enhancement algorithms. This thesis tests different methods within the scale-space framework and evaluate their performance as fingerprint image enhancement methods. </p><p>The methods tested within this thesis ranges from linear scale-space filtering, where no prior information about the images is known, to scalar and tensor driven diffusion where analysis of the images precedes and controls the diffusion process. </p><p>The linear scale-space approach is shown to improve correlation values, which was anticipated since the image structure is flattened at coarser scales. There is however no increase in the number of accurate matches, since inaccurate features also tends to get higher correlation value at large scales. </p><p>The nonlinear isotropic scale-space (scalar dependent diffusion), or the edge- preservation, approach is proven to be an ill fit method for fingerprint image enhancement. This is due to the fact that the analysis of edges may be unreliable, since edge structure is often distorted in fingerprints affected by the template ageing problem. </p><p>The nonlinear anisotropic scale-space (tensor dependent diffusion), or coherence-enhancing, method does not give any overall improvements of the number of accurate matches. It is however shown that for a certain type of template ageing problem, where the deviating structure does not significantly affect the ridge orientation, the nonlinear anisotropic diffusion is able to accurately match correlation pairs that resulted in a false match before they were enhanced.</p>

<p>På SMHI hanteras stora mängder geografisk information som idag studeras med tvådimensionella metoder. Flerdimensionella metoder används mycket sparsamt inom verksamheten, trots att de atmosfäriska processerna sker i alla tre rumsdimensionerna och förändras med tiden. Inom SMHI är de allra flesta vana och nöjda med de tvådimensionella visualiseringsmetoderna och känner stor arbetsglädje i dagens arbetssätt. Bland annat är meteorologernas utbildning helt anpassad efter dagens 2D-visualiseringar. Många tycker heller inte att det finns tid att lära sig nya metoder och verktyg samtidigt som det dagliga arbetet måste utföras. De exempel på flerdimensionell visualisering som man haft tidigare, har inte slagit igenom bland annat på grund av ogenomtänkta användargränssnitt samt begränsad prestanda och hastighet hos systemen. De höga kostnader som visualiseringarna tidigare har inneburit i form av dyr hårdvara och mjukvara är en ytterligare orsak till varför flerdimensionella visualiseringar inte används inom SMHI. </p><p>För att ta ställning till användandet av flerdimensionella visualiseringar måste dess mervärde definieras. Mervärde handlar om att addera mer värde till någonting. Det är ett positivt begrepp i bemärkelsen att det möjliggör, avlastar eller ger tydliga fördelar. Gällande mervärdet med 3D är det mycket viktigt att 3D inte användas för sakens skull utan för att förbättra trovärdigheten, förståelsen och förmedlingen av informationen. Flerdimensionella visualiseringar ska ge en ökad effektivitet och ökad kvalitet jämfört med 2D om de ska vara värdefulla att använda. Ofta är det så att kombinationen av 2D tillsammans med 3D ger styrkan. Det handlar alltså inte om att strikt använda det ena eller andra visualiseringssättet. </p><p>Andra företag liknande SMHI har gjort seriösa försök att införa flerdimensionella visualiseringar i det dagliga arbetet. Exempel på tillämpningar där dessa företag har upptäckt det största mervärdet är bland annat vid visualisering av lokala prognoser med högupplöst data (1-16 km upplösning). Andra exempel är när man vill få eller ge mer information, snabbt unna överblicka mycket data, eller i utbildnings-sammanhang och marknadsföringssyften. Flerdimensionella visualiseringar passar också mycket bra när man vill gå tillbaka och kontrollera ett fel i exempelvis en prognos eller modell. </p><p>Slutsatsen från utvärderingarna av de flerdimensionella applikationerna Vis5D och RAVE i 3D visar att systemen skulle vara användbara för speciella sammanhang inom SMHI, som komplement till dagens tvådimensionella visualiseringssystem. Systemen underlättar upptäckten av vissa väderfenomen samt ger entydlig uppfattning om vädrets fördelning i rummet. </p><p>För att införa flerdimensionella visualiseringar i större utsträckning på SMHI är det viktigt att tänka på den inlärningstid och förändringsprocess som krävs för att man ska kunna lära sig att hantera en tredje rumsdimension. Personalen måste se användandet av visualiseringarna som en kompetenshöjning och något som kan tillföra arbetet något positivt. Att hitta fler goda exempel genom pilotstudier eller exjobb är ett sätt som fler kan få upp ögonen för hur flerdimensionella visualiseringar kan se ut och användas.</p>

<p>This thesis-project aims to research the possibilities of new wireless technologies in general control-situations. We have studied different existing control protocols, and developed a new protocol focusing on textbased menus. Our protocol is scaleable, easy to implement, and platform- and media independent. Since our protocol supports Plug and Play with dynamically allocated id’s, it does not require a unique id in the hardware. </p><p>To test the protocol we have developed a prototype system, consisting of a mobile phone connected to a server, which in turn is connected to two slave units, controlling peripheral equipment on 220 Volt. </p><p>The phone is an <i>Ericsson T28,</i> equipped with a Bluetooth unit. The server is runningthe real-time OS <i>eCos </i>on an A<i>RM 7TDMI Evaluation Kit</i>, and the slave units consist of two developer boards equipped with <i>PIC-processors</i>. Communication between the phone and the server is done over Bluetooth. However we did not find a working Bluetooth protocol stack ported to eCos, so a serial cable was used instead. Communication between the server and the slaves is done over a RS-485 serial network which simulates the traffic over a radio-network. </p><p>The results show that our protocol is working, and that our system would be easy to implement, cheap to produce and very scalable.</p>

På SMHI hanteras stora mängder geografisk information som idag studeras med tvådimensionella metoder. Flerdimensionella metoder används mycket sparsamt inom verksamheten, trots att de atmosfäriska processerna sker i alla tre rumsdimensionerna och förändras med tiden. Inom SMHI är de allra flesta vana och nöjda med de tvådimensionella visualiseringsmetoderna och känner stor arbetsglädje i dagens arbetssätt. Bland annat är meteorologernas utbildning helt anpassad efter dagens 2D-visualiseringar. Många tycker heller inte att det finns tid att lära sig nya metoder och verktyg samtidigt som det dagliga arbetet måste utföras. De exempel på flerdimensionell visualisering som man haft tidigare, har inte slagit igenom bland annat på grund av ogenomtänkta användargränssnitt samt begränsad prestanda och hastighet hos systemen. De höga kostnader som visualiseringarna tidigare har inneburit i form av dyr hårdvara och mjukvara är en ytterligare orsak till varför flerdimensionella visualiseringar inte används inom SMHI. För att ta ställning till användandet av flerdimensionella visualiseringar måste dess mervärde definieras. Mervärde handlar om att addera mer värde till någonting. Det är ett positivt begrepp i bemärkelsen att det möjliggör, avlastar eller ger tydliga fördelar. Gällande mervärdet med 3D är det mycket viktigt att 3D inte användas för sakens skull utan för att förbättra trovärdigheten, förståelsen och förmedlingen av informationen. Flerdimensionella visualiseringar ska ge en ökad effektivitet och ökad kvalitet jämfört med 2D om de ska vara värdefulla att använda. Ofta är det så att kombinationen av 2D tillsammans med 3D ger styrkan. Det handlar alltså inte om att strikt använda det ena eller andra visualiseringssättet. Andra företag liknande SMHI har gjort seriösa försök att införa flerdimensionella visualiseringar i det dagliga arbetet. Exempel på tillämpningar där dessa företag har upptäckt det största mervärdet är bland annat vid visualisering av lokala prognoser med högupplöst data (1-16 km upplösning). Andra exempel är när man vill få eller ge mer information, snabbt unna överblicka mycket data, eller i utbildnings-sammanhang och marknadsföringssyften. Flerdimensionella visualiseringar passar också mycket bra när man vill gå tillbaka och kontrollera ett fel i exempelvis en prognos eller modell. Slutsatsen från utvärderingarna av de flerdimensionella applikationerna Vis5D och RAVE i 3D visar att systemen skulle vara användbara för speciella sammanhang inom SMHI, som komplement till dagens tvådimensionella visualiseringssystem. Systemen underlättar upptäckten av vissa väderfenomen samt ger entydlig uppfattning om vädrets fördelning i rummet. För att införa flerdimensionella visualiseringar i större utsträckning på SMHI är det viktigt att tänka på den inlärningstid och förändringsprocess som krävs för att man ska kunna lära sig att hantera en tredje rumsdimension. Personalen måste se användandet av visualiseringarna som en kompetenshöjning och något som kan tillföra arbetet något positivt. Att hitta fler goda exempel genom pilotstudier eller exjobb är ett sätt som fler kan få upp ögonen för hur flerdimensionella visualiseringar kan se ut och användas.

The usage of automatic fingerprint identification systems as a means of identification and/or verification have increased substantially during the last couple of years. It is well known that small deviations may occur within a fingerprint over time, a problem referred to as template ageing. This problem, and other reasons for deviations between two images of the same fingerprint, complicates the identification/verification process, since distinct features may appear somewhat different in the two images that are matched. Commonly used to try and minimise this type of problem are different kinds of fingerprint image enhancement algorithms. This thesis tests different methods within the scale-space framework and evaluate their performance as fingerprint image enhancement methods. The methods tested within this thesis ranges from linear scale-space filtering, where no prior information about the images is known, to scalar and tensor driven diffusion where analysis of the images precedes and controls the diffusion process. The linear scale-space approach is shown to improve correlation values, which was anticipated since the image structure is flattened at coarser scales. There is however no increase in the number of accurate matches, since inaccurate features also tends to get higher correlation value at large scales. The nonlinear isotropic scale-space (scalar dependent diffusion), or the edge- preservation, approach is proven to be an ill fit method for fingerprint image enhancement. This is due to the fact that the analysis of edges may be unreliable, since edge structure is often distorted in fingerprints affected by the template ageing problem. The nonlinear anisotropic scale-space (tensor dependent diffusion), or coherence-enhancing, method does not give any overall improvements of the number of accurate matches. It is however shown that for a certain type of template ageing problem, where the deviating structure does not significantly affect the ridge orientation, the nonlinear anisotropic diffusion is able to accurately match correlation pairs that resulted in a false match before they were enhanced.

The progression of technical development has yielded practicable camera systems for the acquisition of so called depth maps, images with depth information. Images and movies with depth information open the door for new types of applications in the area of computer graphics and vision. That implies that they will need to be processed in all increasing volumes. Increased depth image processing puts forth the demand for a standardized data format for the exchange of image data with depth information, both still and animated. Software to convert acquired depth data to such videoformats is highly necessary. This diploma thesis sheds light on many of the issues that come with this new task group. It spans from data acquisition over readily available software for the data encoding to possible future applications. Further, a software architecture fulfilling all of the mentioned demands is presented. The encoder is comprised of a collection of UNIX programs that generate MPEG Z/Alpha, an MPEG2 based video format. MPEG Z/Alpha contains beside MPEG2's standard data streams one extra data stream to store image depth information (and transparency). The decoder suite, called TexMPEG, is a C library for the in-memory decompression of MPEG Z/Alpha. Much effort has been put into video decoder parallelization, and TexMPEG is now capable of decoding multiple video streams, not only in parallel internally, but also with inherent frame synchronization between parallely decoded MPEG videos.

With the 1999 introduction of IEEE 802.11b, the 2.4 GHz Wireless Local Area Network (WLAN) standard, the WLAN market finally began to experience the growth levels that had been expected for so long. Now, 5 GHz solutions, with the IEEE 802.11a standard leading the way, offer higher throughput and more efficient use of the spectrum. Just as the 2.4 GHz band, the 5 GHz band is unlicensed. A common concern to all unlicensed bands is interference between devices using the spectrum. Furthermore, in the 5 GHz band, WLAN cells can interfere with radar systems operating at the same frequencies. This report describes a software model, WOK, suitable for simulations of IEEE 802.11a WLANs operating in various environments and under various ambient conditions. The WOK model can be configured extensively with respect to topology, traffic behavior, channel models, signal attenuation, interference sources and radar systems. Further, the concepts of Dynamic Frequency Selection (DFS) and link adaptation are explored in the context of the IEEE 802.11a standard. DFS aims to avoid channels occupied by radar systems and link adaptation aims to maximize the throughput based on current ambient conditions. A DFS algorithm and a link adaptation algorithm are implemented at the Medium Access Control (MAC) layer and evaluated using the WOK model.