6,692 research outputs found
An efficient rate control algorithm for a wavelet video codec
Rate control plays an essential role in video coding and transmission to provide the best video quality at the receiver's end given the constraint of certain network conditions. In this paper, a rate control algorithm using the Quality Factor (QF) optimization method is proposed for the wavelet-based video codec and implemented on an open source Dirac video encoder. A mathematical model which we call Rate-QF (R - QF) model is derived to generate the optimum QF for the current coding frame according to the target bitrate. The proposed algorithm is a complete one pass process and does not require complex mathematical calculation. The process of calculating the QF is quite simple and further calculation is not required for each coded frame. The experimental results show that the proposed algorithm can control the bitrate precisely (within 1% of target bitrate in average). Moreover, the variation of bitrate over each Group of Pictures (GOPs) is lower than that of H.264. This is an advantage in preventing the buffer overflow and underflow for real-time multimedia data streaming
Seeing the trees as well as the forest: the importance of managing forest genetic resources
Reliable data on the status and trends of forest genetic resources are essential for their sustainable management. The reviews presented in this special edition of Forest Ecology and Management on forest genetic resources complement the first ever synthesis of the State of the Worldâs Forest Genetic Resources (SOW-FGR) that has just been published by the Food and Agriculture Organization. In this editorial, we present some of the key findings of the SOW-FGR and introduce the seven reviews presented in this special edition on: (1) tree genetic resources and livelihoods; (2) the benefits and dangers of international germplasm transfers; (3) genetic indicators for monitoring threats to populations and the effectiveness of ameliorative actions; (4) the genetic impacts of timber management practices; (5) genetic considerations in forest ecosystem restoration projects using native trees; (6) genetic-level responses to climate change; and (7) ex situ conservation approaches and their integration with in situ methods. Recommendations for action arising from the SOW-FGR, which are captured in the first Global Plan of Action for the Conservation, Sustainable Use and Development of Forest Genetic Resources, and the above articles are discussed. These include: increasing the awareness of the importance of and threats to forest genetic resources and the mainstreaming of genetic considerations into forest management and restoration; establishing common garden provenance trials to support restoration and climate change initiatives that extend to currently little-researched tree species; streamlining processes for germplasm exchange internationally for research and development; and the intelligent use of modern molecular marker methods as genetic indicators in management and for improvement purposes
Field trials and test results of portable DVB-T systems with transmit delay diversity
This paper describes work carried out by Brunel University and Broadreach Systems (UK) to quantify the advantages that can be achieved if Transmit Diversity is applied to systems employing the DVB standard. The techniques investigated can be applied to standard receiver equipment without modification. An extensive and carefully planned field trial was performed during the winter of 2007/2008 in Uxbridge (UK) to validate predictions from theoretical modeling and laboratory simulations. The transmissions were performed in the 730 MHz frequency band with a DVB-T transmitter and a mean power of 18.4dBW. Transmit delay diversity has been observed to deliver significant reception improvement in automotive and indoor- non line of sight situations
Sampling Considerations in Human Immunodeficiency Virus and Acquired Immunodeficiency Syndrome Needs Assessments
The human immunodeficiency virus (HIV) reduces the number of healthy immune cells in the human body. When the immune cells drop below a certain level, the person is diagnosed as having acquired immunodeficiency syndrome (AIDS), which increases the likelihood of opportunistic infections. As a result, people living with HIV I AIDS (PL WH/ A) have an elevated need for medical and support services. HIV I AIDS needs assessments identify unmet needs, and the results are used in the allocation of resources. Failure to accurately identify needs due to nonrepresentative samples may result in PL WH/ A failing to receive needed services. Random sampling is rarely used, but convenience sampling may provide representative samples if the principles of generalization are followed. The purpose of this study was to assess the degree to which lack of representation is occurring, to assess the impact of lack of representation, and to explore ways to improve the representative qualities of a sample
Assessing the Health-Related Service Needs of People Living With Human Immunodeficiency Virus: A Review of Ryan White Title II Needs Assessments
The Health Resources and Services Administration (HRSA) allocated $940 million in 2002, through Title II of the Ryan White Comprehensive AIDS Resources Emergency (CARE) Act, to help states improve the quality and availability of health related services for people living with HIV/AIDS . These resources are allocated based upon recommendations made by community planning committees, which in turn base their recommendations on HIV/AIDS needs assessments. A methodologically sound, comprehensive needs assessment is a critical component of effective resource allocation decisions. Poor needs assessments might lead to poor resource allocation decisions, which might have life-threatening consequences for people living with HIV/AIDS. Little is known about the quality of Ryan White Title II (RWTII) needs assessments. This dissertation identifies seven elements of a high quality needs assessment, which might serve as an assessment tool for funding agencies and as a guidance tool for grantees. The author uses the seven elements in a review of RWTII needs assessments to provide evidence pertaining to the current level of quality of RWTII needs assessments. The seven elements are then applied in a case study of improved practice to demonstrate how to adequately apply the key elements of a high quality needs assessment
Building the Foundation for the CropManage Nitrogen Fertilizer Decision Support Framework to Guide Hawaiâi's Vegetable Production Systems.
M.S. Thesis. University of HawaiÊ»i at MÄnoa 2018
Safer Prescription Opioid Use in the Greater Danbury Area
Opioid use disorder continues to be a major public health concern worldwide, with over 16 million people affected, and is associated with increased health care costs, reduced quality of life, lost productivity, and loss of life due to opioid overdose deaths. The neurobiology and susceptibility for opioid dependence and addiction is not well-understood by patients, and the lack of understanding of the safe use of prescription opioid regarding its intended effect of pain-relief versus other potential side effects and withdrawal symptoms may lead to misuse. This community health improvement project aims to empower patients and their family members to better understand indications for opioid use, improve awareness of potential for addiction, how to recognize signs and symptoms of misuse, and how to manage their opioid use through safe storage and disposal practices.https://scholarworks.uvm.edu/fmclerk/1973/thumbnail.jp
A search for neutrino-antineutrino mass inequality by means of sterile neutrino oscillometry
The investigation of the oscillation pattern induced by the sterile neutrinos
might determine the oscillation parameters, and at the same time, allow to
probe CPT symmetry in the leptonic sector through neutrino-antineutrino mass
inequality. We propose to use a large scintillation detector like JUNO or LENA
to detect electron neutrinos and electron antineutrinos from MCi electron
capture or beta decay sources. Our calculations indicate that such an
experiment is realistic and could be performed in parallel to the current
research plans for JUNO and RENO. Requiring at least 5 confidence level
and assuming the values of the oscillation parameters indicated by the current
global fit, we would be able to detect neutrino-antineutrino mass inequality of
the order of 0.5% or larger, which would imply a signal of CPT anomalies.Comment: 14 pages, 10 figure
Parallelised max-log-MAP model
A paralleliscd max-Log-MAP model (P-max-Log-MAP) that exploits the sub-word parallelism and very long instruction word architccture of a microprocessor or a digital signal processor (DSP) is presented. The proposed model rcduccs considerably thc computational complexity
of the max-Log-MAP algorithm; valid therefore facilitates easy implementation
A specification-based IDS for detecting attacks on RPL-based network topology
Routing Protocol for Low power and Lossy network (RPL) topology attacks can downgrade the network performance significantly by disrupting the optimal protocol structure. To detect such threats, we propose a RPL-specification, obtained by a semi-auto profiling technique that constructs a high-level abstract of operations through network simulation traces, to use as reference for verifying the node behaviors. This specification, including all the legitimate protocol states and transitions with corresponding statistics, will be implemented as a set of rules in the intrusion detection agents, in the form of the cluster heads propagated to monitor the whole network. In order to save resources, we set the cluster members to report related information about itself and other neighbors to the cluster head instead of making the head overhearing all the communication. As a result, information about a cluster member will be reported by different neighbors, which allow the cluster head to do cross-check. We propose to record the sequence in RPL Information Object (DIO) and Information Solicitation (DIS) messages to eliminate the synchronized issue created by the delay in transmitting the report, in which the cluster head only does cross-check on information that come from sources with the same sequence. Simulation results show that the proposed Intrusion Detection System (IDS) has a high accuracy rate in detecting RPL topology attacks, while only creating insignificant overhead (about 6.3%) that enable its scalability in large-scale network
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