Distributed video coding for wireless video sensor networks: a review of the state-of-the-art architectures

Distributed video coding (DVC) is a relatively new video coding architecture originated from two fundamental theorems namely, Slepian–Wolf and Wyner–Ziv. Recent research developments have made DVC attractive for applications in the emerging domain of wireless video sensor networks (WVSNs). This paper reviews the state-of-the-art DVC architectures with a focus on understanding their opportunities and gaps in addressing the operational requirements and application needs of WVSNs

Layered Wyner-Ziv video coding: a new approach to video compression and delivery

Following recent theoretical works on successive Wyner-Ziv coding, we propose a practical layered Wyner-Ziv video coder using the DCT, nested scalar quantiza- tion, and irregular LDPC code based Slepian-Wolf coding (or lossless source coding with side information at the decoder). Our main novelty is to use the base layer of a standard scalable video coder (e.g., MPEG-4/H.26L FGS or H.263+) as the decoder side information and perform layered Wyner-Ziv coding for quality enhance- ment. Similar to FGS coding, there is no performance di®erence between layered and monolithic Wyner-Ziv coding when the enhancement bitstream is generated in our proposed coder. Using an H.26L coded version as the base layer, experiments indicate that Wyner-Ziv coding gives slightly worse performance than FGS coding when the channel (for both the base and enhancement layers) is noiseless. However, when the channel is noisy, extensive simulations of video transmission over wireless networks conforming to the CDMA2000 1X standard show that H.26L base layer coding plus Wyner-Ziv enhancement layer coding are more robust against channel errors than H.26L FGS coding. These results demonstrate that layered Wyner-Ziv video coding is a promising new technique for video streaming over wireless networks. For scalable video transmission over the Internet and 3G wireless networks, we propose a system for receiver-driven layered multicast based on layered Wyner-Ziv video coding and digital fountain coding. Digital fountain codes are near-capacity erasure codes that are ideally suited for multicast applications because of their rate- less property. By combining an error-resilient Wyner-Ziv video coder and rateless fountain codes, our system allows reliable multicast of high-quality video to an arbi- trary number of heterogeneous receivers without the requirement of feedback chan- nels. Extending this work on separate source-channel coding, we consider distributed joint source-channel coding by using a single channel code for both video compression (via Slepian-Wolf coding) and packet loss protection. We choose Raptor codes - the best approximation to a digital fountain - and address in detail both encoder and de- coder designs. Simulation results show that, compared to one separate design using Slepian-Wolf compression plus erasure protection and another based on FGS coding plus erasure protection, the proposed joint design provides better video quality at the same number of transmitted packets

Source-channel coding for robust image transmission and for dirty-paper coding

In this dissertation, we studied two seemingly uncorrelated, but conceptually related problems in terms of source-channel coding: 1) wireless image transmission and 2) Costa ("dirty-paper") code design. In the first part of the dissertation, we consider progressive image transmission over a wireless system employing space-time coded OFDM. The space-time coded OFDM system based on a newly built broadband MIMO fading model is theoretically evaluated by assuming perfect channel state information (CSI) at the receiver for coherent detection. Then an adaptive modulation scheme is proposed to pick the constellation size that offers the best reconstructed image quality for each average signal-to-noise ratio (SNR). A more practical scenario is also considered without the assumption of perfect CSI. We employ low-complexity decision-feedback decoding for differentially space- time coded OFDM systems to exploit transmitter diversity. For JSCC, we adopt a product channel code structure that is proven to provide powerful error protection and bursty error correction. To further improve the system performance, we also apply the powerful iterative (turbo) coding techniques and propose the iterative decoding of differentially space-time coded multiple descriptions of images. The second part of the dissertation deals with practical dirty-paper code designs. We first invoke an information-theoretical interpretation of algebraic binning and motivate the code design guidelines in terms of source-channel coding. Then two dirty-paper code designs are proposed. The first is a nested turbo construction based on soft-output trellis-coded quantization (SOTCQ) for source coding and turbo trellis- coded modulation (TTCM) for channel coding. A novel procedure is devised to balance the dimensionalities of the equivalent lattice codes corresponding to SOTCQ and TTCM. The second dirty-paper code design employs TCQ and IRA codes for near-capacity performance. This is done by synergistically combining TCQ with IRA codes so that they work together as well as they do individually. Our TCQ/IRA design approaches the dirty-paper capacity limit at the low rate regime (e.g., < 1:0 bit/sample), while our nested SOTCQ/TTCM scheme provides the best performs so far at medium-to-high rates (e.g., >= 1:0 bit/sample). Thus the two proposed practical code designs are complementary to each other

Student Nurses’ Experience of Learning with Human Patient Simulation

Human patient simulation (HPS) has been used for over 40 years in medical education. A human patient simulator is a life-like, anatomically correct, computer driven mannequin with physiologic responses that mimic real patients. Since the introduction of computerized HPS in 2000, its use by medical and nursing students has grown exponentially. Approximately 500 nursing schools are using human patient simulators in nursing education. Researchers have suggested that using HPS can assist in reducing the gaps between theory and practice by improving critical thinking, decision making and patient outcomes. An increase in recognition of medical errors has dictated the need to improve education by allowing students and clinicians to learn in an environment that permits errors and do not put real patients in danger. However, there is a dearth of research on the benefits, advantages and disadvantages of HPS as well as the learning experiences of students who used HPS in their nursing education. Therefore, the purpose of this qualitative study was to describe and analyze the learning experience of baccalaureate nursing students who used HPS during their education. Focus group interviews with HPS students were recorded and transcribed for content analysis in NVIVO, a qualitative analysis software program. The results of the analysis were categorized into four major themes: Structure, Environment, Instructor and Learning. The findings revealed that HPS students felt that structure was critical to optimize learning opportunities. Students wanted to be properly oriented to the environment of the HPS sessions, and they felt that the lack of realism of the simulators did not negatively affect their learning. Students wanted knowledgeable and competent instructors who had good interpersonal communication and interaction skills. Last, students expressed that there were benefits from acting as both the nurse and the observer during HPS. The opportunity to make mistakes without harming a patient and to experience different types of nurse-to-nurse reports were viewed as positive. The findings of the study suggested that further research about student perceptions of HPS learning experiences could provide valuable information for educators and policymakers to improve the implementation of HPS in nursing and medical education

Young Adult Cancer Survivors' Experiences of Connectedness with Their Healthcare Providers

Indiana University-Purdue University Indianapolis (IUPUI)Adolescents and young adults with cancer have poorer treatment and survivorship outcomes than either younger or older cancer patients. These individuals also have psychosocial late effects and engage in lifestyle behaviors that increase their risk of subsequent cancer and other chronic illnesses. Thus, there is a need to identify protective factors during the diagnosis and treatment period to foster healthy lifestyle behaviors. Connectedness with healthcare providers is a potential protective factor that may diminish risk-taking behaviors and foster healthcare self-management in adolescents with cancer. However, little is known about connectedness with healthcare providers from adolescents with cancer perspectives. The purpose of this study was to describe young adult cancer survivors' experiences of connectedness with their healthcare providers as they negotiated the experience across the cancer continuum from diagnosis to survivorship during adolescence. A qualitative, empirical phenomenological method guided this research. The sample consisted of 9 young adult cancer survivors who had cancer as adolescents. A broad, data generating question was constructed to elicit rich, narrative descriptions of participants' experiences of connectedness with healthcare providers, which were audio-taped and transcribed. The narrative data were analyzed using Colaizzi's method, which involved a systematic process of extracting and analyzing significant statements for formulated meanings and themes. Seven theme categories were identified and then used to develop a narrative of the essential structure of the experience of connectedness. Connectedness with healthcare providers is a multi-faceted experience that encompasses instances of not only connectedness, but also unconnectedness and disconnectedness. Effective strategies that foster connectedness with adolescents were identified. Behaviors that foster disconnectedness relate to a lack of respect for the adolescent's personhood. Findings indicate that connectedness with healthcare providers may make adolescents more likely to engage in care partnerships and effective self-management during treatment and into survivorship. When there is no connectedness or a disconnection with healthcare providers, a door shuts: there are feelings of helplessness and vulnerability, anger and resentment, and reluctance to connect with healthcare providers for cancer prevention. Clinical implications for healthcare providers are discussed. Future research should focus on connectedness theory development, measures, and interventions that foster adolescent-provider connectedness