2,424 research outputs found
The asymptotic workload behavior of two coupled queues
Full text linkThe asymptotic workload behavior of two coupled queues S.C. Borst, O.J. Boxma, M.J.G. van Uiter
Synapse distribution on VCH, an inhibitory, motion-sensitive interneuron in the fly visual system
Full text linkGauck V, Egelhaaf M, Borst A. Synapse distribution on VCH, an inhibitory, motion-sensitive interneuron in the fly visual system. JOURNAL OF COMPARATIVE NEUROLOGY. 1997;381(4):489-499
Natural Variation of the Circadian Clock in Neurospora
No full textMost living organisms on earth experience daily and expected changes from the rotation of the earth. For an organism, the ability to predict and prepare for incoming stresses or resources is a very important skill for survival. This cellular process of measuring daily time of the day is collectively called the circadian clock. Because of its fundamental role in survival in nature, there is a great interest in studying the natural variation of the circadian clock. However, characterizing the genetic and molecular mechanisms underlying natural variation of circadian clocks remains a challenging task. In this chapter, we will summarize the progress in studying natural variation of the circadian clock in the successful eukaryotic model Neurospora, which led to discovering many design principles of the molecular mechanisms of the eukaryotic circadian clock. Despite the success of the system in revealing the molecular mechanisms of the circadian clock, Neurospora has not been utilized to extensively study natural variation. We will review the challenges that hindered the natural variation studies in Neurospora, and how they were overcome. We will also review the advantages of Neurospora for natural variation studies. Since Neurospora is the model fungal species for circadian study, it represents over 5 million species of fungi on earth. These fungi play important roles in ecosystems on earth, and as such Neurospora could serve as an important model for understanding the ecological role of natural variation in fungal circadian clocks.Advances in Genetics, Vol. 99
Corrigendum to “A generic multi-level framework for microscopic traffic simulation with automated vehicles in mixed traffic” [Transport. Res. Part C: Emerg. Technol. 110 (2020) 291–311] (Transportation Research Part C (2020) 110 (291–311), (S0968090X19304322), (10.1016/j.trc.2019.11.019))
No full textThe authors regret that a contributing author was missing from the list of authors. The complete list of authors should be: “S.C. Calvert, B. van Arem, & J. W. C. van Lint”. All are with Delft University of Technology, Department of Transport & Planning, The Netherlands updated as above. The authors would like to apologise for any inconvenience caused.Transport and Plannin
Towards the Holy Grail: combining system dynamics and discrete-event simulation in healthcare
No full textThe idea of combining discrete-event simulation and system dynamics has been a topic of debate in theoperations research community for over a decade. Many authors have considered the potential benefits ofsuch an approach from a methodological or practical standpoint. However, despite numerous examples ofmodels with both discrete and continuous parameters in the computer science and engineering literature,nobody in the OR field has yet succeeded in developing a genuinely hybrid approach which truly integratesthe philosophical approach and technical merits of both DES and SD in a single model. In this paperwe consider some of the reasons for this and describe two practical healthcare examples of combinedDES/SD models, which nevertheless fall short of the “holy grail” which has been so widely discussed inthe literature over the past decade
Stochastische modellen voor random-access-netwerken
No full textDraadloze communicatienetwerken spelen een cruciale rol in het verbinden van laptops, smartphones, sensoren en talloze fysieke apparaten, en zijn van vitaal belang voor het uitwisselen van data tussen personen, computerbreinen en andere elementen in onze informatiemaatschappij. Wegens de immense schaalgrootte en fijnmazige infrastructuur, is het onmogelijk centraal de regie te voeren over het dataverkeer in deze netwerken. Doorgaans worden dan ook zogenaamde random-access-algoritmen gebruikt, waar individuele gebruikers de datastromen op autonome wijze aansturen. Sem Borst, Johan van Leeuwaarden en Peter van de Ven beschrijven in dit artikel stochastische deeltjesmodellen om het macroscopische gedrag van deze netwerken te begrijpen en de prestaties te verbeteren
User-level performance of channel-aware scheduling algorithms in wireless data networks
Full text linkChannel-aware scheduling strategies, such as the Proportional Fair algorithm for the CDMA 1xEV-DO system, provide an effective mechanism for improving throughput performance in wireless data networks by exploiting channel fluctuations. The performance of channel-aware scheduling algorithms has mostly been explored at the packet level for a static user population, often assuming infinite backlogs. In the present paper, we focus on the performance at the flow level in a dynamic setting with random finite-size service demands. We show that in certain cases the user-level performance may be evaluated by means of a multi-class Processor-Sharing model where the total service rate varies with the total number of users. The latter model provides explicit formulas for the distribution of the number of active users of the various classes, the mean response times, the blocking probabilities, and the mean throughput. In addition we show that, in the presence of channel variations, greedy, myopic strategies which maximize throughput in a static scenario, may result in sub-optimal throughput performance for a dynamic user configuration and cause potential instability effects
Hybrid simulation for health and social care: the way forward, or more trouble than it’s worth?
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