| 1. |
- Granlund, Gösta H.
(författare)
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A Nonlinear, Image-content Dependent Measure of Image Quality
- 1977
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, considerable research effort has been devoted to the development of useful descriptors for image quality. The attempts have been hampered by i n complete understanding of the operation of the human visual system. This has made it difficult to relate physical measures and perceptual traits.A new model for determination of image quality is proposed. Its main feature is that it tries to invoke image content into consideration. The model builds upon a theory of image linearization, which means that the information in an image can well enough be represented using linear segments or structures within local spatial regions and frequency ranges. This implies a l so a suggestion that information in an image has to do with one- dimensional correlations. This gives a possibility to separate image content from noise in images, and measure them both.Also a hypothesis is proposed that the visual system of humans does in fact perform such a linearization.
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| 2. |
- Blom, Rolf, et al.
(författare)
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Data Network Security : Part I Problem Survey and Model
- 1977
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Data encryption and related methods may be used to preserve information security i n a data network. Here information security is defined as the degree to which the destruction, change or loss of information is presented. Information is defined as the content of the message represented by the data. The information in a block of data is unchanged if the intended result of the transmission of the block is obtained. This means for example that the original message reaches the correct destination where it is interpreted as intended. Undisturbed information does not, in general, require un disturbed data.The network is supposed to be a public network, accessed by many different users. We are interested in a well defined group of users who are communicating mainly among themselves. Different groups, however, are also allowed to communicate in a well defined manner. The logical structure of the communication within a group is star-shaped. The information communicated within the groups hall be protected against threats from other users of the network, from illegitimate users (wiretappers etc) and from members in the group. The structure of the threats is described in section 3 of this paper.The network itself and the requirement it imposes are supposed to be unchanged. Encryption and decryption are taking place outside the network. The encrypted data shall comply with the requirements of the network. The communication process in the group consists of time-limited messages which are essentially transmitted from one point to another in the network. This is the basis for the model of the communication which is described in section 4. The model, although simple, enables us to structure the problems in connection with encryption/decryption. This is done in section 5 and 6. The purpose of the paper is to form a basis for synthesis of security measures by means on cryptological methods. The analysis is general enough to be applied to any data network and any type of user group.
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| 3. |
- Ingemarsson, Ingemar
(författare)
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Encryption in Telefax
- 1978
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Our standpoint is that the basic need for information security in TELETEX is provided by the data network used together with the possibility to encrypt the messages in the terminals, thereby protecting the messages from information loss. Means for detection of information destruction or change and f or verification at unencrypted data may then be provided for by the user of the TELETEX system.
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| 4. |
- Rowa, Per, et al.
(författare)
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Automated Malaria Parasite Detection
- 1977
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A system for malaria parasite detection in thin blood-smears is presented. Sample slides prepared with standard methods are accepted. A low-cost TV-camera mounted on an ordinary microscope with a computer controlled stage is used as a picture sensor. Frames, digitized in windows of 64 x 64 pixels are fed into a special purpose picture processor at normal frame rate (25 frames/sec). In the picture processor measurements are made on the images at high speed. The classification problem is split into different levels each having different characteristics such as different sampling density. Four classes, three of which are different types of malaria parasites, are recognized. As a whole the classification is best labelled as a sequential pattern recognition procedure.In its preliminary version the system has been run at a speed comparable to that of a human operator, that is l 500 cells per minute. A test on 80 000 cells gave 25 false negatives out of 283 parasites (9%) and 41 false positives (0.05%).
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| 5. |
- Ingemarsson, Ingemar, et al.
(författare)
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Computer Security 1981
- 1976
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The goal of COMPUTER SECURITY 1981 is to prediet the demand for protection of eleetronic data processing (EDP) and for the information processed. To predict the future demands on computer security we have discussed the issue with several people involved in one way or another with EDP. These discussions, our own knowledge other background material have been the material for discussions amongst the authors. The results are divided into two parts. In the first part (section 4) we have been as objective as possible. In the latter part (section 5) we have discussed the differences between the results in section 4 and our own opinion as proffessional researchers.In addition the report covers a summary of how EDP is used 1981 and a section describing the structure of the security field (which we have used in the interviews) and an outline of the investigation.
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| 6. |
- Ingemarsson, Ingemar
(författare)
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Några reflektioner kring elektroniska betalningsmedel
- 1979
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- De här nedskrivna tankarna är en frukt av diskussioner med bankfolk och datasäkerhetsforskare rörande olika problem med elektroniska betalningsmedel. De utgör ett försök att formulera de mest grundläggande egenskaperna i viss mån för betalningsmedel i allmänhet och för elektroniska i synnerhet. Syftet är att skapa diskussion kring de problem (främst säkerhetsproblem) som en allmän användning av elektroniska betalningsmedel kan ge upphov till.
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| 7. |
- Rowa, Per, et al.
(författare)
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Datoriserad mätning av vita blodkroppars rörelse
- 1978
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna skrift redovisar försök att kvantitativt mäta rörelsen hos levande vita blodkroppar .Mätningarna sker helt automatiskt och i reell tid.Bilden av preparatet överförs via en TV-kamera på mikroskopet till en dator. Datorn utnyttjar en speciell bildprocessor för bildoperationer och mätvärdesextraktion .Cellernas individuella rörelser både i form av globala tyngdpunktsförflyttningar och lokala formförändringar uppmäts. För hela populationen beräknas en mängd statistiska uppgifter och resultatkurvor uppritas under mätningen .Praktiska och principiella svårigheter vid analysen av TV-bilden beskrivs utförligt.
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| 8. |
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