| 51. |
- Fan, Xing, 1975-, et al.
(författare)
-
Efficient Support for High Traffic-Volumes of Short-Message Real-Time Communication Using an Active Ethernet Switch
- 2004
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Ingår i: Proceedings of the 10th International Conference on Real-time and Embedded Computing Systems and Applications (RTCSA’04). ; , s. 517-533
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Konferensbidrag (refereegranskat)abstract
- There are several different types of communication traffic with real- time demands apparent in distributed industrial and embedded systems, for example, group communication and process synchronization. The length of these messages is often very short but the traffic volume might be really high. Standard network protocols do not normally reach very high utilization for such small messages. This paper presents a solution to efficiently support real-time short message communication over switched Ethernet. In our proposal, the Ethernet switch and the end-nodes are enhanced to combine several short messages into an Ethernet frame to improve the performance, and to give the short-message traffic real-time support on two levels, short-frame level and Ethernet frame level. Earliest Deadline First (EDF) scheduling is used in the switch and in the source nodes on both these two levels. We have characterized the performance of the network in terms of channel utilization and the number of accepted real-time channels, by simulations of the network assuming Fast Ethernet. We also show, by example, that we can reach an improvement of the possible short-message rate of 66%.
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| 52. |
- Fan, Xing, 1975-, et al.
(författare)
-
Guaranteed Real-Time Services in Switched Ethernet Networks with Deadline Scheduling in the End Nodes
- 2004
-
Konferensbidrag (refereegranskat)abstract
- This paper proposes a switched Ethernet network that supports real-time communication with guaranteed bit rate and end-to-end delay bound. In our proposal, the source nodes use Earliest Deadline First (EDF) scheduling, while the switch uses First Come First Served (FCFS) to control periodic real-time traffic belonging to logical realtime connections. The schedulability condition is drawn and the end-to-end worst-case delay bound is derived for guaranteed real-time traffic, which also gives, as a sub-result, the needed buffer space in the switch. Moreover, different traffic classes are prioritized and put into different output queues in the end nodes and the switch, which minimizes the interference with other traffic when transmitting periodic time-critical messages. The solution requires no additional hardware or software modifications of the switch and the underlying standard. It is based purely on software implementation in the end nodes. Furthermore, the EDF scheduling strategy used in the source nodes allows good resource utilization, while the FCFS scheduling used in the switch limits the switch processing overhead. The paper presents simulation analysis for Fast Ethernet, which verifies our approach of guaranteeing real-time transmission at the same time as achieving high utilization.
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| 53. |
- Fan, Xing, 1975-
(författare)
-
Real-Time Communication Services for Distributed Computing over Switched Ethernet
- 2004
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In modern and future parallel and distributed processing, a large part of computation overhead comes from communication. This can be minimized if the network protocol offers the user services that are aimed at specific types of communication used in these applications. Other important properties of distributed processing applications are time-deterministic latency and guarantees to meet deadlines. Moreover, an important trend is to implement distributed real-time applications on top of standard Ethernet based networks. Therefore, in this thesis, we focus on developing and analyzing how to efficiently support real-time communication services for distributed computing applications over switched Ethernet. The network architecture currently assumed is a switched Ethernet network with only one switch.The work has resulted in proposed Switched Ethernet networks that offer additional features for parallel and distributed real-time processing. An active Ethernet switch concept is proposed to provide efficient support for different user services, including many-to-many communication and other group communication services with high traffic volumes of short messages. Meanwhile, the real-time support for these special communication patterns is addressed by incorporating deadline-based scheduling in the switch and the end nodes.Moreover, this thesis addresses real-time services by proposing an alternative solution. In this proposal, the Earliest Deadline First (EDF) algorithm is only used in the source nodes to support real-time traffic with a guaranteed bit rate and end-to-end worst-case delay bound. The thesis also reports a feasibility analysis for hard real-time traffic, which also produces figures on the minimum buffer sizes in the switch to be able to guarantee real-time demands. Meanwhile, differentiation of heterogeneous traffic is considered in the proposed system by placing traffic into several priority classes with distinctly different QoS levels.The performance of the proposed methods is evaluated in simulations and calculations. It is shown that the different Ethernet extensions, in many cases, are efficient choices for distributed computing systems.
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| 54. |
- Fierrez-Aguilar, Julian, et al.
(författare)
-
Kernel-based multimodal biometric verification using quality signals
- 2004
-
Ingår i: Proceedings of SPIE. - : SPIE. ; , s. 544-554
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A novel kernel-based fusion strategy is presented. It is based on SVM classifiers, trade-off coefficients introduced in the standard SVM training and testing procedures, and quality measures of the input biometric signals. Experimental results on a prototype application based on voice and fingerprint traits are reported. The benefits of using the two modalities as compared to only using one of them are revealed. This is achieved by using a novel experimental procedure in which multi-modal verification performance tests are compared with multi-probe tests of the individual subsystems. Appropriate selection of the parameters of the proposed quality-based scheme leads to a quality-based fusion scheme outperforming the raw fusion strategy without considering quality signals. In particular, a relative improvement of 18% is obtained for small SVM training set size by using only fingerprint quality labels.
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| 55. |
- Fjæstad, Björn, 1943-, et al.
(författare)
-
Gentekniken vinner terräng
- 2004
-
Ingår i: Ekengrens svenska. - Stockholm : Natur och kultur. - 9127595269
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 56. |
- Flemme, Inger, 1947-
(författare)
-
Health-related quality of life in recipients with an implantable cardioverter defibrillator due to life-threatening arrhythmias : a 5 year follow-up
- 2004
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The general aim of this thesis was to describe self-reported health-related quality of life (HRQoL) in recipients with an implantable cardioverter defibrillator (ICD) due to life-threatening arrhythmias over a 5-year period. The design was prospective and longitudinal. Fifty-six patients participated in Paper I, and 35 of these patients, who had survived at least five years, were included in paper II. All patients had received their ICD as a form of secondary prevention. The Quality of Life Index-Cardiac version (QLI-C), Mishel Uncertainty in Illness Scale-Community version (MUIS-C), and multiple regression analysis were used. Higher scores indicate higher HRQoL and uncertainty. The questionnaires were completed on four occasions: before implantation, at three months and at 1 year and 5 years after implantation. ICD recipients were also asked how many shocks they had perceived. At the 5-year data collection, the average ICD recipient had lived with an ICD for 6 years and 9 months. In general HRQoL was lower at year 1 than at baseline (p = 0-033). A decrease in the socioeconomic domain was observed at year 1 (p = 0.006) but improved again at year 5 (p = 0.027) although it remained below the baseline value. ICD recipients' satisfaction with the family domain decreased from the time of the ICD implantation (p < 0.001) and from year 1 (p = 0.039) to year 5 after implantation. Uncertainty related to information had decreased at year 1 in relation to baseline (p < 0.001). A decrease in overall uncertainty was observed at year 5 in relation to year 1 (p = 0.009) as well as at year 6 in relation to baseline (p = 0.009). The longer the ICD recipient had lived with the device, the greater the risk of receiving a shock. However, ICD recipients who received shocks reported being less troubled by them over time. Uncertainty was identified as a predictor of Low HRQoL. The recipients reported a higher level of HRQoL at year 5 than at year 1. HRQoL was reasonably good 5 years after implantation, and the ICD recipients felt more secure and perceived their ICD as a lifesaver.
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| 57. |
- Flemme, Inger, 1947-, et al.
(författare)
-
Livskvalitet och upplevda chocker under ICD-behandling : en 5-års uppföljning
- 2004
-
Konferensbidrag (refereegranskat)abstract
- ICD–behandling ökar överlevnaden hos patienter (pat), som har överlevt en malign ventrikulär tachyarytmi. Pats livskvalitet (QoL) har angivits variera betydande och långtidseffekterna är ännu mindre väl kända. Vi följde ett antal konsekutiva pat under minst 5 år med avseende på livskvaliteten.Metod. Pat undersöktes med MUIS-C (Mishel Uncertainty in Illness Scale – community version) och QLI-CV (Quality of Life Index – cardiac version) och multipel regressionsanalys användes hos 35 patienter. Formulären fylldes i vid tre tillfällen: före implantationen, efter 1 och 5 år. Pats egen uppfattning om antalet upplevda chocker oavsett anledning noterades.Patienter. Ur en grupp pat, som tidigare undersöktes efter 1 år, hade 39 pat överlevt med sin ICD i minst 5 år. Av dessa avböjde tre deltagande i uppföljningen utan orsak och en pga cancer. Alla pat hade fått sin ICD på indikationen sekundär prevention. Resultat. Under det första året rapporterade 13 pat totalt 79 chocker och 22 pat ingen chock. Tio pat hade ingen chock vare sig efter 1 eller 5 år, och deras QoL var likvärdig med dem som hade haft ≤5 chocker. Tre pat rapporterade ≥6 chocker och hade sänkt QoL. Mellan år 1 och 5 rapporterade 20 pat 94 shocker och 15 pat ingen shock. Det var ingen skillnad mellan pat med eller utan chocker i deras QoL år 5 vs. år 1. Pat med chocker blev mindre besvärade med tiden.QoL var generellt sänkt år 1 vs baseline. En försämring i den socio-ekonomiska domänen sågs år 1 men var förbättrad år 5. En försämring i familjedomänen var oförändrad vid 1 och 5 år vs. baseline. En förbättring av otrygghet noterades vid 5 år vs år 1.Konklusioner. Pat med ICD mådde bättre år 5 än år 1 efter implantationen. Livskvaliteten var rimligt god 5 år efter implantationen och pat kände sig mer trygga och upplevde sin ICD som en livräddare. Pat med många chocker under det första året mådde sämre än övriga. Under resten av observationsperioden var chocktätheten lägre, möjligen delvis pga farmakologisk behandling, och pat upplevde mindre besvär av chockerna.
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| 58. |
- Flemme, Inger, et al.
(författare)
-
Quality of profile 1 and 5 years after ICD implantation
- 2004
-
Ingår i: European Journal of Cardiovascular Nursing. - Amsterdam : Elsevier. - 1873-1953.
-
Konferensbidrag (refereegranskat)abstract
- Aim: Treatment with implantable cardioverter defibrillators (ICDs) increases survival in patients suffering from ventricular tachyarrhythmias. The physiologic effects of having an ICD implanted are well-known but there is still limited knowledge about quality of life (QoL), especially in a long-term perspective. Therefore, the aim of this prospective, follow-up study was to describe and compare uncertainty and QoL at year 1 and year 5 after implantation in patients living with an ICD.Methods: The Mishel Uncertainty in Illness Scale-community version (MUIS-C) and Quality of Life Index-cardiac version (QLI) was used for 35 patients, living with an ICD in average 6 years 9 months. Higher scores indicate higher uncertainty and QoL.Results: An improvement in uncertainty was found at year 5 compared to year 1 (p=0.009), and at year 5 compared to baseline (p = 0.009). Overall QoL decreased at year 1 compared to baseline (p = 0.033). QoL in the socioeconomic domain decreased at year 1 compared to baseline (p = 0.006), and increased at year 5 compared to year 1 (p=0.027). QoL in the family domain decreased at year 5 compared to year 1 (p=0.039), and at year 5 compared to baseline (p=<0.001).Conclusion: Patients with ICD feel better at year 5 than at year 1. The QoL is reasonable good 5 years after implant once they have passed the first years and adapted to lifestyle changes, and patients are more certain and perceive the ICD as a parachute of life.
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| 59. |
- Florén, Henrik, et al.
(författare)
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The emergent prerequisites of managerial learning in small firm networks
- 2004
-
Ingår i: Leadership & Organization Development Journal. - Bradford : MCB Publishing. - 0143-7739 .- 1472-5347. ; 25:3/4, s. 292-307
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Tidskriftsartikel (refereegranskat)abstract
- Descriptive studies have shown that co-operation in networks produces better possibilities for higher-level learning than small firms can organise on their own. Previous studies of learning in networks, however, have not considered how the prerequisites for higher-level learning develop over time in networks. This paper reports on a seven-year participant observational study of two different network constellations. A conclusion from the study is that the learning in networks of small-firm owner/managers is based on trust and has emergent prerequisites. These prerequisites are reciprocity between learning actors, the learning actors’ receptive and confronting capacity, and the transparency of the dialogue in the networks. Over time these prerequisites develop and create better opportunities for higher-level learning.
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| 60. |
- Florén, Henrik, et al.
(författare)
-
What do owner-managers in small firms really do? : Differences in managerial behavior in small and large organizations
- 2004
-
Ingår i: Small Enterprise Research. - Caulfield East, Vic. : School of Accounting, Monash University. - 1321-5906 .- 1175-0979. ; 12:1, s. 57-70
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Tidskriftsartikel (refereegranskat)abstract
- The research presented is a replication of Mintzberg's on managerial work. The article focuses on owner-managers in small manufacturing firms in an initial attempt to reveal the nature of the work undertaken by this type of managers. The purpose is to describe what they do and to compare their behaviour with that of managers in large and intermediate organizations as described by Mintzberg and Kurke & Aldrich. Our study compliments an earlier small-scale study on managerial behavior in small firms and includes sufficient data to test Mintzberg's propositions on managerial work. Empirically this paper draws on an observational study that deployed the method of structured observation. The daily activities of the small-firm owner-managers in our study are characterized by, among other things, informality and constant interruption as the process by which their work is organized. This differs partly from the results found in the studies of managers' work in larger organizations, where formal and planned activities serve more often as the procedure through which the managers design their work. Of Mintzberg's seven propositions, we found support for four, although with some hesitation. This calls into question the asserted generality of several such propositions. Our study indicates that there seem to be certain myths about what small-firm owner-managers really do, myths that need to be considered in future research.
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