Search results for " Allocation"
showing 10 items of 502 documents
Analysis of load balancing and interference management in heterogeneous cellular networks
2017
To meet the current cellular capacity demands, proactive offloading is required in heterogeneous cellular networks (HetCNets) comprising of different tiers of base stations (BSs), e.g., small-cell BSs (sBSs) and conventional macro-cell BSs (mBSs). Each tier differs from the others in terms of BS transmit power, spatial density, and association bias. Consequently, the coverage range of each tier BSs is also different from others. Due to low transmit power, a fewer number of users are associated to an sBS as compared with mBS. Thus, inefficient utilization of small-cell resources occurs. To balance the load across the network, it is necessary to push users to the underloaded small cells from …
GARCH models with changes in variance: An approximation to risk measurements
2003
This study aims to model volatility as an approximation to an optimum measurement of stock market risk because of the importance of this concept for, among other things, the proper management of portfolios. Following the proposal of Lamoureux and Lastrapes (1990), the authors consider that the high degree of persistence detected in GARCH models arises from a poor specification of the equation of the variance due to not considering the possible deterministic changes in the unconditional variance of the financial series. To determine the point in time as well as the duration of these changes, the proposal made by Inclan and Tiao (1994) is used. As an empirical application, whether or not the …
Solving Stochastic Nonlinear Resource Allocation Problems Using a Hierarchy of Twofold Resource Allocation Automata
2010
In a multitude of real-world situations, resources must be allocated based on incomplete and noisy information. However, in many cases, incomplete and noisy information render traditional resource allocation techniques ineffective. The decentralized Learning Automata Knapsack Game (LAKG) was recently proposed for solving one such class of problems, namely the class of Stochastic Nonlinear Fractional Knapsack Problems. Empirically, the LAKG was shown to yield a superior performance when compared to methods which are based on traditional parameter estimation schemes. This paper presents a completely new online Learning Automata (LA) system, namely the Hierarchy of Twofold Resource Allocation …
Modeling Human Resources Management in Maritime Container Terminals
2012
Over the last few decades, competition among maritime container terminals has increased due to large growth rates on major seaborne container routes. Thus terminals have to carefully plan the management of their facilities and services in order to satisfy shipping companies’ demands. Failure to do so will lead customers to re-schedule their routes calling at new promising terminals. As a result, and so as not to lose competitiveness, container terminals are showing a growing interest in advanced decision support systems for their management, in which optimization methods play a crucial role. In this context, the optimal management of human resources is a major issue for terminals, particula…
AN OPTIMIZATION MODEL FOR DAILY MANPOWER ALLOCATION IN TRANSSHIPMENT CONTAINER TERMINALS
2011
This work is motivated by the manpower allocation problem arising at the Cagliari International Terminal Container. Generally speaking, human resources allocation plays a key role in terminals with high labor costs, in order to achieve high levels of productivity and quality services for customers. As a result, terminal containers exhibit a growing interest in advanced decision support systems, in which optimization methods play a crucial role. In this talk we present an optimization model for manpower allocation in transshipment container terminals. The objective is to determine the optimal daily allocation of crane operators and trailer drivers at an operational planning level, taking int…
Scheduling solution for the IEEE 802.16 base station
2008
The IEEE 802.16 standard defines a wireless broadband access network technology called WiMAX. It introduces several advantages, one of which is the support for QoS at the MAC level. To ensure meeting the QoS requirements, the 802.16 base station must run some algorithm to allocate slots between connections. This algorithm is not defined in the 802.16 specification but rather is open for alternative implementations. We propose a simple, yet efficient, solution that is capable of allocating slots based on the QoS requirements, bandwidth request sizes, and the 802.16 network parameters. To test the proposed solution, we have implemented the 802.16 MAC and PHY layers in the NS-2 simulator. Seve…
The real-life performance of market timing with moving average and time-series momentum rules
2014
In this article, we revisit the myths regarding the superior performance of market timing strategies based on moving average and time-series momentum rules. These active timing strategies are very appealing to investors because of their extraordinary simplicity and because they promise substantial advantages over their passive counterparts. However, the ‘too good to be true’ reported performance of these market timing rules raises a legitimate concern as to whether this performance is realistic and whether investors can expect that future performance will be the same as the documented historical performance. We argue that the reported performance of market timing strategies usually contains…
Emotional after‐effects on the P3 component of the event‐related brain potential
2003
Agrowing body of literature indicates that affective states can influence cognitive processes. The core assumption of Ellis and Ashbrook's (1988) model explaining these emotional after-effects on cognition is that the emotional state regulates the allocation of processing resources. A negative emotional state is supposed to pre-empt capacity normally allocated to the cognitive task at hand. This is assumed to occur because the negative emotional state leads to an increase in intrusive, irrelevant thoughts, which compete with relevant cognitive activities and thus result in a lack of attention given to relevant features of the task to be performed. In the present study, the hypothesis that n…
An overview of the Ephydridae (Diptera) of Saudi Arabia
2019
Despite the species richness of Ephydridae world-wide (2000 species) and its prominent environmental roles as a minor pest and as a food for wildlife, only 13 species have been recorded from Saudi Arabia. Between 2012 and 2016, a biodiversity study of Diptera was conducted at Jazan, Asir, and Najran in south-western Saudi Arabia, at 22 sites, was performed mainly using Malaise traps and sweep nets. In this study, 43 known species of Ephydridae were identified, 37 of them for the first time from southwestern Saudi Arabia and 16 from Arabian Peninsula. This brings the total number of Ephydridae species in Saudi Arabia to 49 (including previous records). There were a further four species, whic…
An Experimental Testbed and Methodology for Characterizing IEEE 802.11 Network Cards
2006
It has been observed that IEEE 802.11 commercial cards produced by different vendors show a different behavior in terms of perceived throughput or access delay. Performance differences are evident both when the cards contend alone to the channel, and when heterogeneous cards contend together. Since the performance misalignment does not disappear by averaging the environmental factors (such as propagation conditions, laptop models, traffic generators, etc), it is evident that the well known throughput-fairness property of the DCF protocol is not guaranteed in actual networks. In this paper we propose a methodological approach devised to experimentally characterize the IEEE 802.11 commercial …