The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform
E L Hahne - One of the best experts on this subject based on the ideXlab platform.
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dynamic queue Length thresholds for shared memory packet switches
IEEE ACM Transactions on Networking, 1998Co-Authors: A K Choudhury, E L HahneAbstract:In shared-memory packet switches, buffer management schemes can improve overall loss performance, as well as fairness, by regulating the sharing of memory among the different output port queues. Of the conventional schemes, static threshold (ST) is simple but does not adapt to changing traffic conditions, while pushout (PO) is highly adaptive but difficult to implement. We propose a novel scheme called dynamic threshold (DT) that combines the simplicity of ST and the adaptivity of PO. The key idea is that the maximum Permissible Length, for any individual queue at any instant of time, is proportional to the unused buffering in the switch. A queue whose Length equals or exceeds the current threshold value may accept no more arrivals. An analysis of the DT algorithm shows that a small amount of buffer space is (intentionally) left unallocated, and that the remaining buffer space becomes equally distributed among the active output queues. We use computer simulation to compare the loss performance of DT, ST, and PO. DT control is shown to be more robust to uncertainties and changes in traffic conditions than ST control.
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dynamic queue Length thresholds in a shared memory atm switch
International Conference on Computer Communications, 1996Co-Authors: A K Choudhury, E L HahneAbstract:Buffer management schemes are needed to fairly regulate the sharing of memory among different output port queues in a shared memory ATM switch. Of the conventional schemes, static threshold is simple but does not adapt to changing traffic conditions while pushout is efficient and adaptive but difficult to implement. We propose a novel scheme called dynamic threshold which combines the simplicity of static threshold and the adaptability of pushout. The key idea is that the maximum Permissible Length, for any individual queue at any instant of time, is proportional to the unused buffering in the switch. A queue whose Length equals or exceeds the current threshold value may accept no more new cells. The dynamic threshold procedure presented improves the fairness and switch efficiency by guaranteeing access to the buffer space for all output queues. Computer simulation is used to compare the loss performance of the dynamic threshold technique with that of static threshold and pushout. The dynamic threshold scheme is shown to be a good compromise: while nearly as simple as static threshold control, it offers most of the performance benefits of pushout. Like pushout, the dynamic threshold method is adaptive, so it is more robust to uncertainties and changes in traffic conditions than, static threshold control.
A K Choudhury - One of the best experts on this subject based on the ideXlab platform.
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dynamic queue Length thresholds for shared memory packet switches
IEEE ACM Transactions on Networking, 1998Co-Authors: A K Choudhury, E L HahneAbstract:In shared-memory packet switches, buffer management schemes can improve overall loss performance, as well as fairness, by regulating the sharing of memory among the different output port queues. Of the conventional schemes, static threshold (ST) is simple but does not adapt to changing traffic conditions, while pushout (PO) is highly adaptive but difficult to implement. We propose a novel scheme called dynamic threshold (DT) that combines the simplicity of ST and the adaptivity of PO. The key idea is that the maximum Permissible Length, for any individual queue at any instant of time, is proportional to the unused buffering in the switch. A queue whose Length equals or exceeds the current threshold value may accept no more arrivals. An analysis of the DT algorithm shows that a small amount of buffer space is (intentionally) left unallocated, and that the remaining buffer space becomes equally distributed among the active output queues. We use computer simulation to compare the loss performance of DT, ST, and PO. DT control is shown to be more robust to uncertainties and changes in traffic conditions than ST control.
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dynamic queue Length thresholds in a shared memory atm switch
International Conference on Computer Communications, 1996Co-Authors: A K Choudhury, E L HahneAbstract:Buffer management schemes are needed to fairly regulate the sharing of memory among different output port queues in a shared memory ATM switch. Of the conventional schemes, static threshold is simple but does not adapt to changing traffic conditions while pushout is efficient and adaptive but difficult to implement. We propose a novel scheme called dynamic threshold which combines the simplicity of static threshold and the adaptability of pushout. The key idea is that the maximum Permissible Length, for any individual queue at any instant of time, is proportional to the unused buffering in the switch. A queue whose Length equals or exceeds the current threshold value may accept no more new cells. The dynamic threshold procedure presented improves the fairness and switch efficiency by guaranteeing access to the buffer space for all output queues. Computer simulation is used to compare the loss performance of the dynamic threshold technique with that of static threshold and pushout. The dynamic threshold scheme is shown to be a good compromise: while nearly as simple as static threshold control, it offers most of the performance benefits of pushout. Like pushout, the dynamic threshold method is adaptive, so it is more robust to uncertainties and changes in traffic conditions than, static threshold control.
Нижевский, Виктор Ильич - One of the best experts on this subject based on the ideXlab platform.
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Calculation estimation of overvoltage on insulation of the equipment of a substation at the lightning strike in its lightning arrester
'National Technical University Kharkiv Polytechnic Institute', 2019Co-Authors: Нижевский, Илья Викторович, Нижевский, Виктор ИльичAbstract:Разработан инженерный подход к расчету грозовых перенапряжений на оборудовании подстанции при ударе молнии в молниеотвод. Сформулированы условия безопасного для оборудования прохождения тока молнии по молниеотводу. Показано, что расчет допустимой длины воздушных изоляционных промежутков на подстанции базируется на основе пробивной напряженности воздуха, которая принята равной500 кВ/м. Это приводит к ошибке расчета длины воздушного промежутка и, как следствие, вероятности его пробоя, значение которой используется для расчета показателя грозоупорности подстанции. В качестве примера рассмотрена методика расчета допустимого напряжения на корпусе трансформатора при ударе молнии в молниеприемник трансформаторного портала. На основе нелинейной импульсной электрической прочности грунта получено уточненное минимальное допустимое расстояние в земле между заземлителем молниеотвода и ближайшей к нему точкой защищаемого устройства. Приводятся аналитические выражения для расчетов.Purpose.The complex approach to calculating thunderstorm overvoltage on substation equipment is considered when light-ning strikes in a lightning rod. Methodology.The conditions of safe passage of lightning current through a lightning arrester are formulated. Results. It is shown that the calculation of the Permissible Length of air insulating gaps in the substation is based on the breakdown of the air tension, which is assumed to be 500 kV/m. This leads to an error in calculating the Length of the air gap and, as a consequence, the probability of its breakdown, the value of which is used to calculate the indicator of the lightning resistance of the substation. A technique is proposed for calculating the Permissible voltage on the trans-former case when a lightning strike strikes the lightning receptacle of the transformer portal. On the basis of the nonlinear pulsed electric strength of the ground, the specified minimum Permissible ground distance between the grounding rod of the lightning rod and the nearest pointof the protected device is obtained. Originality.Refined calculation of the Length of the minimum breakdown gap in the air and in the ground. Practical value.The proposed approach makes it possible to calculate thunderstorm overvoltage on substation equipment
J. Caban - One of the best experts on this subject based on the ideXlab platform.
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Determination of the maximum Permissible cargo Length exceeding the articulated vehicle Length in order to detect its critical rotation radius (February 2017)
2018 XI International Science-Technical Conference Automotive Safety, 2018Co-Authors: J. Vrábel, J. Jagelčák, O. Stopka, M. Kiktová, J. CabanAbstract:At present, different cargo types with varied dimensions exceeding vehicles maximum Permissible dimensions are transported by road transport, and thus, their operation can significantly influence road traffic safety across Europe. Slovakia applies Government Regulation No. 349/2009, which also regulates a maximum Permissible dimensions of vehicle categories. This paper deals with cargo the whose dimensions of which exceed the dimensions of the semi-trailer. The paper describes circle of vehicle maneuverability, which states that each vehicle must be able to maneuver in the inner circle as the minimum criterion and must be capable of maneuvering in the outer circle as the maximum criterion. The paper also describes the influence of the truck's fifth wheel axle position on the articulated vehicle total Length, which affects the maximum cargo Permissible Length in the rearward direction. The next part of the paper is about impact of the fifth wheel position to the minimum width of the road lane in depending on wheelbases size of tractor. Within this research study, for the purpose of verifying the theoretical calculations, series of measurements confirming these calculations were performed.
Mazurin Iuv - One of the best experts on this subject based on the ideXlab platform.
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Determination of the Permissible Length of time and amplitude of exposure of man to high-level linear acceleration
Kosmicheskaia biologiia i aviakosmicheskaia meditsina, 1991Co-Authors: Mazurin IuvAbstract:This paper presents examples of application of the experimental-theoretical method for predicting the probability of injury and tolerance of linear acceleration of up to 3 s. Predictions were made using mathematical models and relationships between parameters of model reactions and changes examined.