Selection Policy (selection + policy)

Distribution by Scientific Domains

Selected Abstracts

Applying multiple description coding to enhance the streaming scalability on CDN-P2P network

Chow-Sing Lin
Abstract Owing to the wide deployment of broadband networks, information can now be rapidly disseminated all over the world. Only the content of static texts and pictures has not yet met users' demands. Along with the rapid advance of computer-related technologies, how to efficiently provide multimedia content for a large number of heterogeneous users on the Internet, especially videos, has become a noticeable issue. In this paper, we discuss the adaptation of multiple description coding (MDC) for the loopback buffering mechanism to address the issue of peer heterogeneity on content distribution network,peer to peer (CDN-P2P) video-on-demand systems. Three description selection policies, Ordered, Round-Robin, and Open-Loop-First (OLF), are studied. In addition, we propose the intra-description recovery and inter-description recovery to deal with failed peers. The simulation results show that the OLF with loopback-MDC can significantly reduce the amount of uploading bandwidth of a proxy on CDN-P2P video-on-demand systems, and the inter-description recovery, sewing, can further effectively recover missing blocks and restore the continuity of a breaking sharing loop among peers. Copyright 2009 John Wiley & Sons, Ltd. [source]

Joint queue control and user scheduling in MIMO broadcast channel under zero-forcing multiplexing

Feng She
Abstract This paper studies the problem of queue control and user scheduling in multi-antenna broadcast (downlink) systems under zero forcing beamforming transmit strategy. In the system, we assume that the data packet arrives randomly to the buffered transmitter. By taking the broadcast channel as a controlled queueing system, we deduce the property of queue control function that maximizes the weighted system throughput while guarantees the delay fairness among users. We also present a low-complexity user selection algorithm with the consideration of queue state and channel state together. Simulation results show that the joint queue control and user selection policy can achieve considerable fairness and stability among users. Copyright 2009 John Wiley & Sons, Ltd. [source]

Distinction Bias in Applicant Reactions to Using Diversity Information in Selection

Margaret E. Brooks
Two studies investigated applicant reactions to alternative methods of incorporating diversity in employee selection decisions. Of particular interest was the hypothesized interaction between specific approach to incorporating diversity in the selection policy (holistic vs mechanical) and mode of receiving information about this approach (viewing policies in isolation vs viewing policies simultaneously). Results indicate preference for holistic approaches to incorporating diversity in selection. The magnitude of the preference was much greater when participants evaluated both approaches simultaneously. Results are consistent with the distinction bias, which suggests that people differentiate between options more when they consider them simultaneously than when they view them separately. Findings have implications for applicant reactions research, human resource decision making, and policy formation. [source]

Fractional allelic imbalance could allow for the development of an equitable transplant selection policy for patients with hepatocellular carcinoma

Igor Dvorchik
Liver transplantation (LT) in the presence of hepatocellular carcinoma (HCC) remains a controversial issue because the current staging systems are not sufficiently predictive of outcomes. Paraffin blocks from 183 patients that underwent LT in the presence of HCC were collected. Molecular analysis was carried out blindly on the native liver specimens in all cases with respect to recurrence outcomes. The fractional allelic imbalance (FAI) rate index was determined in each case and was used to compare the acquired mutational load between different tumors. The FAI was determined from the microdissected tissue site displaying the greatest amount of acquired allelic loss. FAI was found to be the strongest predictor of recurrence followed by vascular invasion and then by tumor number or hepatic lobar involvement. Based on these findings, 3 prognostic models were constructed for selection of candidates for LT in patients with concomitant HCC. Molecular markers of tumor progression are the strongest predictors of HCC recurrence currently available, surpassing all components of the tumor-node-metastasis classification system for staging of malignant tumors (TNM), including vascular invasion. Incorporation of these molecular markers of tumor progression could help resolve the ongoing conundrum of organ allocation for patients with HCC. Liver Transpl 2007. 2007 AASLD. [source]

Prior academic background and student performance in assessment in a graduate entry programme

P L Craig
Objectives, This study aims to identify whether non-science graduates perform as well as science graduates in Basic and Clinical Sciences (B & CS) assessments during Years 1,3 of a four-year graduate-entry programme at the University of Sydney (the ,USydMP'). Methods, Students were grouped into five categories: Health Professions (HP), Biomedical Sciences (BMS), Other Biology (BIOL), Physical Sciences (PHYS) or Non-Science (NONS). We examined the performance rank of students in each of the five groups for single best answer (SBA) and modified essay (MEQ) assessments separately, and also calculated the relative risk of failure in the summative assessments in Years 2 and 3. Results, Students with science-based prior degrees performed better in the SBA assessments. The same occurred initially in the MEQs, but the effect diminished with time. The HP students performed consistently better but converged with other groups over time, particularly in the MEQs. Relative performance by the NONS students improved with time in both assessment formats. Overall, differences between the highest and lowest groups were small and very few students failed to meet the overall standard for the summative assessments. HP and BMS students had the lowest failure rate. NONS students were more likely to fail the assessments in Year 2 and 3, but their pass rates were still high. Female students performed significantly better overall at the end of Year 2 and in Year 3. There were only minor differences between Australian resident and International students. Conclusion, While there are small differences in performance in B & CS early in the programme, these lessen with time. The study results will inform decisions regarding timing of summative assessments, selection policy and for providing additional support to students who need it to minimize their risk of failure. Readers should note that this paper refers to student performance in only one of the four curriculum themes, where health professional and science graduates would be expected to have a significant advantage. [source]

Fuzzy Sarsa Learning and the proof of existence of its stationary points,

Vali Derhami
Abstract This paper provides a new Fuzzy Reinforcement Learning (FRL) algorithm based on critic-only architecture. The proposed algorithm, called Fuzzy Sarsa Learning (FSL), tunes the parameters of conclusion parts of the Fuzzy Inference System (FIS) online. Our FSL is based on Sarsa, which approximates the Action Value Function (AVF) and is an on-policy method. In each rule, actions are selected according to the proposed modified Softmax action selection so that the final inferred action selection probability in FSL is equivalent to the standard Softmax formula. We prove the existence of fixed points for the proposed Approximate Action Value Iteration (AAVI). Then, we show that FSL satisfies the necessary conditions that guarantee the existence of stationary points for it, which coincide with the fixed points of the AAVI. We prove that the weight vector of FSL with stationary action selection policy converges to a unique value. We also compare by simulation the performance of FSL and Fuzzy Q-Learning (FQL) in terms of learning speed, and action quality. Moreover, we show by another example the convergence of FSL and the divergence of FQL when both algorithms use a stationary policy. Copyright 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]