Adaptive Allocation Research Articles

A joint-probabilistic programming method for water resources optimal allocation under uncertainty: a case study in the Beiyun River, China

Abstract In recent years, the lower reaches of the Beiyun River have suffered from growing water resource shortages due to the reduction of upstream water resource and drying up of the stream channel. More reasonable and scientifically based water allocation plans should be developed and implemented; however, uncertainties exist regarding the determination of water supply availability and spillage of extra water. To assess and manage regional water shortage, the combined effects of multiple water supply sources as well as the joint probability of typical events should be considered. The joint probability of water supply, considering upstream and local water supplies, was estimated through the copula functions. A multi-objective optimization model was then developed and solved by improved genetic algorithms to plan water resources allocation within a multi-source environment containing multiple competitive users. The framework is demonstrated, and represents a range of different water supply scenarios in terms of different probabilities of occurrence and constraint violations. The results showed that water allocation was greatly influenced by uncertainties, especially in upstream-local water supply. In addition, violating water-allocation constraint posed an extra uncertainty. This study facilitates the proposition of adaption allocation plans for uncertain environments, aiming to balance the shortage, economy, and reliability.

A perception based bit allocation for 3DTV broadcasting

Perceptually adaptive bit allocation plays vital roles in efficient rate control to achieve rate distortion optimization in terms of perceptual video coding. This paper proposes a perceptually improved bit allocation scheme by employing a more accurate distortion model inspired by a state-of-the-art perceptual video quality metric. The contributions of this paper mainly involve the following three aspects. Firstly, a perceptual rate-distortion model is developed to shape the framework of perceptual video coding. Secondly, based on the characteristics of the model, an adaptively frame-level bit allocation scheme is proposed using the rate distortion optimization technology. Meanwhile, the status of the encoder buffer is also taken into account to avoid overflow or underflow. Finally, a macroblock-level quantization parameter adjustment is presented to improve perceptual video quality. Experimental results demonstrate that the whole proposed bit allocation scheme achieves better perceptual rate-distortion performance and guarantees the accuracy of rate control well.

Dynamic power allocation based on second-order control system in two-tier femtocell networks

In this paper, we investigate the joint uplink power allocation problem for the macrocell and femtocells in the new view of Control Theory. Since the wireless channels in the macrocell and the femtocells fluctuate with time, we aim at an energy-saving and adaptive power allocation scheme that is robust to channel fluctuations. An optimal power allocation problem, which can satisfy the requirement of signal-to-interference-plus-noise ratio and subject to the maximum power constraint, is formulated. To obtain the robust power allocation of each user (both macrocell and femtocell users), a second-order control system is created for each cell (macrocell and femtocell). According to the second-order control system and considering the maximum power constraint, we derive a distributed robust power control algorithm. The dynamic performance and convergence of the formulated system are analyzed based on control theory. The advantage of the scheme is that some dynamic control indexes can be set in advance and the dynamic process can be controlled by setting appropriate parameters. Since femtocells share the same spectrum with the macrocell, the interference from femtocells to the macrocell base station has to be controlled to protect the normal communication of the macrocell. Then an admission control algorithm is proposed to remove the user that causes the serious interference to the macrocell, if the signal-to-interference-plus-noise ratio requirement of the macrocell user can not be satisfied. Two algorithms are particularly attractive, especially in view of practical implementation issues. Numerical simulation results are presented to illustrate the effectiveness and advantages of the proposed algorithms.

저전력 광역 통신 시스템을 위한 채널 적응형 대역폭 할당 방법

저전력 광역 통신 시스템을 위한 채널 적응형 대역폭 할당 방법

Highly Efficient Adaptive Bandwidth Allocation Algorithm for WDM/OFDM-PON-Based Elastic Optical Access Networks

Highly Efficient Adaptive Bandwidth Allocation Algorithm for WDM/OFDM-PON-Based Elastic Optical Access Networks

Design considerations and analysis planning of a phase 2a proof of concept study in rheumatoid arthritis in the presence of possible non-monotonicity

BackgroundIt is important to quantify the dose response for a drug in phase 2a clinical trials so the optimal doses can then be selected for subsequent late phase trials. In a phase 2a clinical trial of new lead drug being developed for the treatment of rheumatoid arthritis (RA), a U-shaped dose response curve was observed. In the light of this result further research was undertaken to design an efficient phase 2a proof of concept (PoC) trial for a follow-on compound using the lessons learnt from the lead compound.MethodsThe planned analysis for the Phase 2a trial for GSK123456 was a Bayesian Emax model which assumes the dose-response relationship follows a monotonic sigmoid “S” shaped curve. This model was found to be suboptimal to model the U-shaped dose response observed in the data from this trial and alternatives approaches were needed to be considered for the next compound for which a Normal dynamic linear model (NDLM) is proposed. This paper compares the statistical properties of the Bayesian Emax model and NDLM model and both models are evaluated using simulation in the context of adaptive Phase 2a PoC design under a variety of assumed dose response curves: linear, Emax model, U-shaped model, and flat response.ResultsIt is shown that the NDLM method is flexible and can handle a wide variety of dose-responses, including monotonic and non-monotonic relationships. In comparison to the NDLM model the Emax model excelled with higher probability of selecting ED90 and smaller average sample size, when the true dose response followed Emax like curve. In addition, the type I error, probability of incorrectly concluding a drug may work when it does not, is inflated with the Bayesian NDLM model in all scenarios which would represent a development risk to pharmaceutical company.The bias, which is the difference between the estimated effect from the Emax and NDLM models and the simulated value, is comparable if the true dose response follows a placebo like curve, an Emax like curve, or log linear shape curve under fixed dose allocation, no adaptive allocation, half adaptive and adaptive scenarios. The bias though is significantly increased for the Emax model if the true dose response follows a U-shaped curve.ConclusionsIn most cases the Bayesian Emax model works effectively and efficiently, with low bias and good probability of success in case of monotonic dose response. However, if there is a belief that the dose response could be non-monotonic then the NDLM is the superior model to assess the dose response.

A flexible resource scheduling scheme for an adaptive SCMA system

Sparse code multiple access (SCMA) is a new type of non-orthogonal multiple access technology, and it originates from low-density signature (LDS) technology. SCMA can obtain an additional coding gain through the codebook design. Combining the concepts of OFDMA and CDMA, SCMA has the advantages of high capacity, low time delay and high data rate. We propose adaptive allocation technology (AAT) and design an adaptive SCMA system. The designed system has better flexibility and adaptability than conventional OFDMA and SCMA systems. However, preventing fragmentation of physical resource blocks (PRBs) in the resource scheduling is crucial for rendering the adaptive SCMA system feasible. For this purpose, we design two optional resource scheduling schemes: resource first and user first. The theoretical derivation and simulation results demonstrate the feasibility and superiority of the proposed algorithms and schemes in terms of system throughput and packet loss rate (PLR) performance.

A comparison between two treatments in a clinical trial with an ethical allocation design

ABSTRACTThe present article compares two treatments, say A and B, in the context of a clinical trial. Let X and Y be, respectively, the responses corresponding to A and B which have some continuous distributions. Here, the comparison is done through the parameter which is a very common functional in the context of reliability theory and survival analysis. We consider a two-stage data-dependent adaptive allocation design where the observations on X and Y are collected sequentially in two stages. We use the Mann–Whitney–Wilcoxon (MWW) statistic to provide a statistical comparison by a nonparametric approach. Various asymptotic results related to the proposed procedure are studied. The proposed procedure is also compared with the usual single-stage equal allocation design through statistical and clinical performances of the respective allocation procedures.

On the Optimality of Multi-User Coordinated Zero-Forcing Beamforming Multicell Systems with Limited Feedback in Interference Channels

An efficient multicell coordinated zero-forcing channel feedback scheme is proposed in this paper. The objective of the proposed feedback design is to control the rate of the user by adaptive allocation of feedback bits of each user as a function of individual channel status thereby keeping the total feedback budge constant. The proposed feedback allocation is studied in interfering broadcast channel (IFBC) and also in time varying channels (TVC) with feedback update duration. First the individual feedback rates of user are derived using convex optimization thereby presenting low complexity algorithm to optimize the channel feedback between inter-user interference and inter-cell interference. The rate offset arising from channel quantization in both IFBC and TVC is investigated by employing the coordinated zero forcing beamforming. Moreover, closed form expressions are derived for necessary feedback scaling and frequency of update duration to achieve the multiplexing gain and throughput. Finally, numerical evaluation results show that the proposed channel feedback schemes outperforms other conventional schemes and assist in base station cooperation management. It can be concluded that frequent update of channel state information and suppression of dominant interferences can yield significant improvements in the sumrate performance of limited feedbback systems.

Antenna selection and adaptive power allocation for IA‐based underlay CR

In underlay spectrum sharing cognitive radio (CR), the secondary users (SUs) share the spectrum with the primary users (PUs) in such a way that the interference caused by the SUs should be less than the interference temperature (IT) threshold. Interference Alignment (IA) is considered as a novel interference management technique for CR networks (CRN) which eliminates the interference at the PUs and also the interference among the SUs. However, most of the iterative solutions for IA aimed at removing the interference between the users, does not take into account the QoS (Quality of Service) of the PUs and SUs. Also the achievable rate of PUs by employing IA is less than that of the maximum achievable rate in a MIMO (Multiple input multiple output) system with no interference. In this paper we first present an Antenna Selection (AS) scheme to significantly improve the QoS of PUs and then we have proposed an adaptive power allocation (PA) scheme which aims at optimum PA in view of the proportional fairness among SUs. Numerical results are derived for comparing the proposed schemes in terms of outage performance of PUs and SUs. Simulation results show the effectiveness of the proposed methods in terms of SNR.

Multimedia transmission in MC-CDMA using adaptive subcarrier power allocation and CFO compensation

ABSTRACTMulticarrier code division multiple access (MC-CDMA) system is one of the most effective techniques in fourth-generation (4G) wireless technology, due to its high data rate, high spectral efficiency and resistance to multipath fading. However, MC-CDMA systems are greatly deteriorated by carrier frequency offset (CFO) which is due to Doppler shift and oscillator instabilities. It leads to loss of orthogonality among the subcarriers and causes intercarrier interference (ICI). Water filling algorithm (WFA) is an efficient resource allocation algorithm to solve the power utilisation problems among the subcarriers in time-dispersive channels. The conventional WFA fails to consider the effect of CFO. To perform subcarrier power allocation with reduced CFO and to improve the capacity of MC-CDMA system, residual CFO compensated adaptive subcarrier power allocation algorithm is proposed in this paper. The proposed technique allocates power only to subcarriers with high channel to noise power ratio. The performance of the proposed method is evaluated using random binary data and image as source inputs. Simulation results depict that the bit error rate performance and ICI reduction capability of the proposed modified WFA offered superior performance in both power allocation and image compression for high-quality multimedia transmission in the presence of CFO and imperfect channel state information conditions.

A Highly Utilized Hardware-Based Merge Mode Estimation with Candidate Level Parallel Execution for High-Efficiency Video Coding

The merge mode is one of the new tools adopted in high-efficiency video coding (HEVC) to improve the inter-frame coding efficiency. The merge mode saves the bits for the motion vector (MV) by sharing the MV with neighboring blocks. Merge mode estimation (MME) is the process of finding the merge mode candidate achieving the highest compression efficiency at the cost of extensive computation. This paper tackles the intrinsic inefficiency problem of hardware-based MME and proposes a new hardware-efficient MME scheme which regulates the number of fractional estimation for merge mode candidate including vertically fractional MV. The proposed MME hardware organization in this paper features two different data paths where only one path includes a vertical interpolation filter. The proposed efficient MME scheme reduces the computational complexity of MME by regulating peak computational complexity of vertical interpolation filter. As a result, the proposed MME hardware organization saves hardware resources for vertical interpolation filter. In addition, the proposed hardware maintains high utilization by adopting adaptive candidate allocation scheme which well balances workloads between two independent data paths. Consequently, the proposed MME hardware processes 62,106 of 64 × 64 CTUs per second with a clock frequency of 400 MHz and a gate count of 460.8 K, which correspond to 23% less hardware resources and 17% higher throughput than the conventional MME hardware.

Covariate-adjusted response-adaptive randomization for multi-arm clinical trials using a modified forward looking Gittins index rule.

SummaryWe introduce a non-myopic, covariate-adjusted response adaptive (CARA) allocation design for multi-armed clinical trials. The allocation scheme is a computationally tractable procedure based on the Gittins index solution to the classic multi-armed bandit problem and extends the procedure recently proposed in Villar et al. (2015). Our proposed CARA randomization procedure is defined by reformulating the bandit problem with covariates into a classic bandit problem in which there are multiple combination arms, considering every arm per each covariate category as a distinct treatment arm. We then apply a heuristically modified Gittins index rule to solve the problem and define allocation probabilities from the resulting solution. We report the efficiency, balance, and ethical performance of our approach compared to existing CARA methods using a recently published clinical trial as motivation. The net savings in terms of expected number of treatment failures is considerably larger and probably enough to make this design attractive for certain studies where known covariates are expected to be important, stratification is not desired, treatment failures have a high ethical cost, and the disease under study is rare. In a two-armed context, this patient benefit advantage comes at the expense of increased variability in the allocation proportions and a reduction in statistical power. However, in a multi-armed context, simple modifications of the proposed CARA rule can be incorporated so that an ethical advantage can be offered without sacrificing power in comparison with balanced designs.

Optimal management of nutrient reserves in microorganisms under time-varying environmental conditions

Intracellular reserves are a conspicuous feature of many bacteria; such internal stores are often present in the form of inclusions in which polymeric storage compounds are accumulated. Such reserves tend to increase in times of plenty and be used up in times of scarcity. Mathematical models that describe the dynamical nature of reserve build-up and use are known as “cell quota,” “dynamic energy/nutrient budget,” or “variable-internal-stores” models. Here we present a stoichiometrically consistent macro-chemical model that accounts for variable stores as well as adaptive allocation of building blocks to various types of catalytic machinery. The model posits feedback loops linking expression of assimilatory machinery to reserve density. The precise form of the “regulatory law” at the heart of such a loop expresses how the cell manages internal stores. We demonstrate how this “regulatory law” can be recovered from experimental data using several empirical data sets. We find that stores should be expected to be negligibly small in stable growth-sustaining environments, but prominent in environments characterised by marked fluctuations on time scales commensurate with the inherent dynamic time scale of the organismal system.

A case for further refinement of the Green Climate Fund’s 50:50 ratio climate change mitigation and adaptation allocation framework: toward a more targeted approach

Created in 2010 and made operational in 2015, the Green Climate Fund (GCF) is expected to become the main mechanism for transferring public and some private funds to non-Annex I countries to address climate change. It aims to achieve a 50:50 balance between adaptation and mitigation financing over time. While there is a diplomatic history leading to this arrangement, we argue the GCF’s allocation strategy requires further refinement if it is to adequately address climate change. We advocate prioritizing climate mitigation over adaptation in funding while not ignoring climate justice concerns all together. We recommend a more targeted approach to its funding allocations based upon the GHGs abatement potential for mitigation or climate vulnerability for adaptation of very specific non-Annex I countries. We believe these refinements will help to improve the efficiency and effectiveness of scarce climate change financing resources required to achieve the Intergovernmental Panel on Climate Change’s (IPCC) central objective of no more than 1.5 °C by 2100, which requires emissions reductions between 70 and 95% (2010 levels) by 2050.

Performance Analysis of Efficient Power Allocation Techniques with Different Modulation for 4X4 V-BLAST MIMO-OFDM System

Objectives: To propose an optimal power allocation method for high-speed V-BLAST MIMO-OFDM system for better performance in terms of SNR and BER than the traditional methods. Materials and Methods: To study and evaluate the performance of two linear channel estimators, the Least Square Error (LS) and Linear Minimum Mean Square Error (LMMSE) are used for 4 × 4 VBLAST Multiple input, multiple output-orthogonal frequency division multiplexing (MIMOOFDM) system with different modulation-4 QAM,16QAM and 64 QAM. For power allocation, optimal power is determined by the Greedy Power Allocation and the Cuckoo Search algorithm depending on the condition of the carriers measured from the channel estimation. Findings: Based on the detection method, Vertical Bell Labs Layered Space-Time (V-BLAST) MIMO-OFDM is found to be the high-speed system. Here, the proposed optimal power allocation method for high-speed V-BLAST MIMO-OFDM system showed a better performance in terms of Signal to Noise Ratio (SNR) and BER than the traditional methods. This thesis work has been evaluated based on different channel estimation with different modulation techniques for V-BLAST MMSE MIMO-OFDM System. The test program has been implemented in the latest technology system in Matlab R2013a. The experimental results show that our proposed method achieves better performance in terms of Bit Error Rate (BER) and SNR compared with the existing methods used for improving the performance of the MIMOOFDM. Linear MMSE proved efficient channel estimation technique over LS. MMSE -OSIC achieves very good performance with respect to other detectors in VBLAST MIMO-OFDM environment for 4× 4 MIMO-OFDM systems. Application: This result would be useful to make efficient Adaptive MIMO-OFDM system. It would be also useful in adaptive modulation and power allocation concept for making better wireless communication system. This performance analysis can perform for different channel models.

Measurements of Characteristics of Clutter

Maximum likelihood algorithms for estimating parameters of a correlation matrix of clutter for adaptive allocation of signals of moving targets in multifrequency coherent pulse radar-tracking systems are synthesized. Schematic diagrams of the corresponding measuring instruments are provided.

An adaptive allocation design for circular treatment outcome

A number of allocation designs are developed for continuous and binary treatment outcomes to assign a higher number of subjects to the treatment doing better in course of the trial. However, if the response is circular in nature, the definition of a better treatment differs from that under the linear response and hence the already developed designs lack appropriateness. In the current work, redefining the notions of superiority, we develop an allocation function in the context of circular treatment outcomes. Using a response-adaptive route for practical implementation, we study the resulting design both theoretically and numerically and finally illustrate the performance for a real-life example on cataract surgery.

Prediction complexity-based HEVC parallel processing for asymmetric multicores

This paper proposes a novel Tile allocation method considering the computational ability of asymmetric multicores as well as the computational complexity of each Tile. This paper measures the computational ability of asymmetric multicores in advance, and measures the computational complexity of each Tile by using the amount of HEVC prediction unit (PU) partitioning. The implemented system counts and sorts the amount of PU partitions of each Tile, and also allocates Tiles to asymmetric big.LITTLE cores according to their expected computational complexity. When experiments were conducted, the amount of PU partitioning and the computational complexity (decoding time) showed a close correlation, and average performance gains of decoding time with the proposed adaptive allocation were around 36 % with 12 Tiles, 28 % with 18 Tiles, and 31 % with 24 Tiles, respectively.

Adaptive fairness scheduling and optimisation of power in millimetre wave MIMO-OFDM systems

The demand for higher data rates and spectral efficiency over wireless channels is growing day by day. Mobile multimedia millimetre (mm) wave communication, a key technology for 5G systems offers high date rate and greater spectrum than current cellular standards. The large amounts of bandwidth available in the mmWave band enable multi-Gigabit communication. Adaptive resource allocation and optimisation of power for mobile multimedia is of great research interest. In this paper, an adaptive fairness power allocation scheme for transmission of multimedia images have been proposed for mmWave MIMOOFDM. The results show better error performance, improved PSNR and reduced percentage of pixel errors.