W. M. Kays, Convective Heat and Mass Transfer, 387 pp. McGraw-Hill, New York (1966)

Drake, Robert M.

doi:10.1016/0017-9310(67)90130-5

Cited by 21 publications

(40 citation statements)

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“…If the number of cells passed by an MT is assumed to be a random variable with uniform distribution on [ ], the probability mass function and its transform can be represented as (12) Then, the pdf of the residence time in an LA has Laplace transform as (13) where is computed from (2). From the property of Laplace transform [7], the first-order moment, i.e., the mean value of the residence time in the LA, is (14) As shown in Fig. 1, system and are assumed to be in macrocell and microcell tier, respectively.…”

Section: Calculation Of Intersystem Roaming Probabilitiesmentioning

confidence: 99%

A dynamic location management scheme for next-generation multitier PCS systems

Akyildiz

Wang

2002

IEEE Trans. Wireless Commun.

219

100

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Abstract-Global wireless networks enable mobile users to communicate regardless of their locations. One of the most important issues is location management in a highly dynamic environment because mobile users may roam between different wireless systems, network operators, and geographical regions. In this paper, a location-tracking mechanism is introduced that consists of intersystem location updates and intersystem paging. Intersystem update is implemented by using the concept of boundary location area, which is determined by a dynamic location update policy in which the velocity and the quality of service are taken into account on a per-user basis. Also, intersystem paging is based on the concept of boundary location register, which is used to maintain the records of mobile users crossing the boundary of systems. This mechanism not only reduces location-tracking costs, but also significantly decreases call-loss rates and average-paging delays. The performance evaluation of the proposed schemes is provided to demonstrate their effectiveness in multitier personal communication systems.

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Section: Calculation Of Intersystem Roaming Probabilitiesmentioning

confidence: 99%

A dynamic location management scheme for next-generation multitier PCS systems

Akyildiz

Wang

2002

IEEE Trans. Wireless Commun.

219

100

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“…(The scheduling scheme at the sender is specific to the implementation, and beyond this paper's scope.) If the timeout value of NAK timer (18) is used in place of the timeout value of NAK timer (3), the expected time between the issuance of the first NAK and the nominal reception of the last bit of the last transmission spurt in (5) is replaced by (19) and thus, the expected file-delivery time is (20) in place of (7).…”

Section: Discussionmentioning

confidence: 99%

“…Recall that the expected time until any arrival among independent Poisson processes, each with arrival rate , is [7]. Consider independent Poisson processes, each of which terminates after the first arrival.…”

Section: Discussionmentioning

confidence: 99%

Expected File-Delivery Time of Deferred NAK ARQ in CCSDS File-Delivery Protocol

Lee

Baek

2004

IEEE Trans. Commun.

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Abstract-We analyze an automatic repeat-request (ARQ) scheme of the Consultative Committee for Space Data Systems file-delivery protocol for the single-hop file-transfer operation. With regard to performance measures, this paper is mainly concerned with the time taken to transfer a file (file-delivery time) and throughput efficiency. We discuss the ARQ timer-setting rule that minimizes the expected file-delivery time under the constraint that the throughput efficiency is maximized. Then, for that timer-setting rule, we derive the expected file-delivery time.

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“…Details of probabilistic convolution can be found in the work of Drake [1967]. P T (n > 0jq z ) is the total within-crown gap probability of the canopy, and P h (njq z ), and P c (njq z ) are the probability for a beam of light at zenith angle q z passing n (n = 0, 1, 2, .…”

Section: Modeling Radiation Interception By Forest Canopiesmentioning

confidence: 99%

Energy, water, and carbon fluxes in a loblolly pine stand: Results from uniform and gappy canopy models with comparisons to eddy flux data

et al. 2009

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[1] This study investigates the impacts of canopy structure specification on modeling net radiation (R n ), latent heat flux (LE) and net photosynthesis (A n ) by coupling two contrasting radiation transfer models with a two-leaf photosynthesis model for a maturing loblolly pine stand near Durham, North Carolina, USA. The first radiation transfer model is based on a uniform canopy representation (UCR) that assumes leaves are randomly distributed within the canopy, and the second radiation transfer model is based on a gappy canopy representation (GCR) in which leaves are clumped into individual crowns, thereby forming gaps between the crowns. To isolate the effects of canopy structure on model results, we used identical model parameters taken from the literature for both models. Canopy structure has great impact on energy distribution between the canopy and the forest floor. Comparing the model results, UCR produced lower R n , higher LE and higher A n than GCR. UCR intercepted more shortwave radiation inside the canopy, thus producing less radiation absorption on the forest floor and in turn lower R n . There is a higher degree of nonlinearity between A n estimated by UCR and by GCR than for LE. Most of the difference for LE and A n between UCR and GCR occurred around noon, when gaps between crowns can be seen from the direction of the incident sunbeam. Comparing with eddy-covariance measurements in the same loblolly pine stand from May to September 2001, based on several measures GCR provided more accurate estimates for R n , LE and A n than UCR. The improvements when using GCR were much clearer when comparing the daytime trend of LE and A n for the growing season. Sensitivity analysis showed that UCR produces higher LE and A n estimates than GCR for canopy cover ranging from 0.2 to 0.8. There is a high degree of nonlinearity in the relationship between UCR estimates for A n and those of GCR, particularly when canopy cover is low, and suggests that simple scaling of UCR parameters cannot compensate for differences between the two models. LE from UCR and GCR is also nonlinearly related when canopy cover is low, but the nonlinearity quickly disappears as canopy cover increases, such that LE from UCR and GCR are linearly related and the relationship becomes stronger as canopy cover increases. These results suggest the uniform canopy assumption can lead to underestimation of R n , and overestimation of LE and A n . Given the potential in mapping regional scale forest canopy structure with high spatial resolution optical and Lidar remote sensing plotforms, it is possible to use GCR for up-scaling ecosystem processes from flux tower measurements to heterogeneous landscapes, provided the heterogeneity is not too extreme to modify the flow dynamics.

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W. M. Kays, Convective Heat and Mass Transfer, 387 pp. McGraw-Hill, New York (1966)

Cited by 21 publications

References 0 publications

A dynamic location management scheme for next-generation multitier PCS systems

A dynamic location management scheme for next-generation multitier PCS systems

Expected File-Delivery Time of Deferred NAK ARQ in CCSDS File-Delivery Protocol

Energy, water, and carbon fluxes in a loblolly pine stand: Results from uniform and gappy canopy models with comparisons to eddy flux data

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