The Experts below are selected from a list of 134481 Experts worldwide ranked by ideXlab platform
Panagiotis Papadimitriou - One of the best experts on this subject based on the ideXlab platform.
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Multi-Provider Service Chain Embedding With Nestor
IEEE Transactions on Network and Service Management, 2017Co-Authors: David Dietrich, Ahmed Abujoda, Amr Rizk, Panagiotis PapadimitriouAbstract:Network function (NF) virtualization decouples NFs from the underlying middlebox hardware and promotes their deployment on virtualized network infrastructures. This essentially paves the way for the migration of NFs into clouds (i.e., NF-as-a-Service), achieving a drastic reduction of middlebox investment and operational costs for enterprises. In this context, Service chains (expressing middlebox policies in the enterprise network) should be mapped onto datacenter networks, ensuring correctness, resource efficiency, as well as compliance with the Provider's policy. The network Service embedding (NSE) problem is further exacerbated by two challenging aspects: 1) traffic scaling caused by certain NFs (e.g., caches and WAN optimizers) and 2) NF location dependencies. Traffic scaling requires resource reservations different from the ones specified in the Service chain, whereas NF location dependencies, in conjunction with the limited geographic footprint of NF Providers (NFPs), raise the need for NSE across multiple NFPs. In this paper, we present a holistic solution to the multi-Provider NSE problem. We decompose NSE into: 1) NF-graph partitioning performed by a centralized coordinator and 2) NF-subgraph mapping onto datacenter networks. We present linear programming formulations to derive near-optimal solutions for both problems. We address the challenging aspect of traffic scaling by introducing a new Service model that supports demand transformations. We also define topology abstractions for NF-graph partitioning. Furthermore, we discuss the steps required to embed Service chains across multiple NFPs, using our NSE orchestrator (Nestor). We perform an evaluation study of multi-Provider NSE with emphasis on NF-graph partitioning optimizations tailored to the client and NFPs. Our evaluation results further uncover significant savings in terms of Service cost and resource consumption due to the demand transformations.
Julian D Ford - One of the best experts on this subject based on the ideXlab platform.
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correlates of mental health Service use intensity in the national comorbidity survey and national comorbidity survey replication
Psychiatric Services, 2007Co-Authors: Jon D Elhai, Julian D FordAbstract:Objective: This study explored sociodemographic and mental health correlates of intensity of mental health care use in two large-scale surveys, aiming to discover the set of correlates with the greatest predictive capacity. Methods: Data were examined from persons aged 15 to 54 in two nationally representative U.S. household surveys: the National Comorbidity Survey (NCS) (N=5,877), which gathered information from 1990 to 1992, and the NCS Replication (N=4,320), which gathered information from 2001 to 2003. Outcome variables were the number of mental health care visits in the past year to mental health Providers, social Service Providers, and medical Providers. This study implemented state-of-theart statistical methods designed for modeling such outcomes as treatment intensity—that is, visit counts. Results: Across Provider types, significant univariate associations were found for intensity of mental health care use based on access variables (for example, employment and health insurance) and two need variables—psychiatric diagnoses and psychiatric disability. Demographic variables and treatment need variables were not consistent Service use correlates. Multivariate regression accounting for excessive zero values demonstrated that after the analyses controlled for sociodemographic and access variables, mental disorders (mood, anxiety, and substance use disorders) and psychiatric disability added incrementally to variance in visit counts for mental health care. However, when mental health Service use was dichotomized (any use versus no use) demographic and access variables, as well as psychiatric disorders, emerged as correlates. In both sets of analyses, different patterns of psychiatric disorder and disability were associated with Provider Service use. Conclusions: These findings extend research on correlates of mental health care use, addressing intensity of use, suggesting that sociodemographic factors and presence of a psychiatric disorder and associated disability drive the initial use of Services, whereas presence of a psychiatric disorder and associated disability are associated with continued Service use. (Psychiatric Services 58:1108–1115, 2007)
Vidhyacharan Bhaskar - One of the best experts on this subject based on the ideXlab platform.
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Encrypted token based authentication with adapted SAML technology for cloud web Services
Journal of Network and Computer Applications, 2017Co-Authors: I. Indu, P. M. Rubesh Anand, Vidhyacharan BhaskarAbstract:Web applications and cloud Services are rapidly emerging as the inevitable technology for communication between organizations. Cloud-based solutions are currently deployed to provide improvement in the existing business processes and Services. The major challenge involved in cloud is data security that is stored and transferred. Cloud infrastructure requires an extensive authentication mechanism to protect data as well as to ensure that the right person is accessing the right information. In this paper, token based fine grained authentication for cloud web Services with the help of adapted Security Assertion Markup Language (SAML) technology is proposed. The entire set of communications between Identity Provider, Service Provider and Cloud Server is encrypted to enhance the security. The combination of SAML and single use access token based verification provides improved security to cloud web Services. The proposed adapted SAML authentication mechanism ensures flexibility and scalability of the environment by the provision of adding multiple numbers of trusted sources and web Services.
Raouf Boutaba - One of the best experts on this subject based on the ideXlab platform.
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multi Provider Service negotiation and contracting in network virtualization
Network Operations and Management Symposium, 2010Co-Authors: Fidae Zaheer, Jin Xiao, Raouf BoutabaAbstract:Network virtualization environment (VNE) affords great business flexibility to the customers and the Providers as multiple Providers can jointly support a customer's virtual network. Under the current network model, a group of Infrastructure Providers (InPs) peer with each other to provide a packaged deal. Such a business arrangement is not customer-driven, does not promote fair market competition and does not ensure cost minimization. Furthermore, the on-demand nature of virtual networks requires efficient and automated Service negotiation and contracting. In this paper, we present V-Mart. To the InPs, V-Mart offers an environment to participate in a faithful and fair competition over the VN resources; and to the SPs, it offers a customer-driven virtual resource partitioning and contracting engine. V-Mart uses a two-stage Vickrey auction model that is strategy-proof, flexible to diverse InP pricing models, and functions over heterogenous multi-commodity market that characterizes the NVE. Through analysis and simulation we show the flexibility and effectiveness of V-Mart.
Richard S Chung - One of the best experts on this subject based on the ideXlab platform.
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patient outcomes and evidence based medicine in a preferred Provider organization setting a six year evaluation of a physician pay for performance program
Health Services Research, 2007Co-Authors: Amanda Gilmore, Yingxu Zhao, Ning Kang, Kira L Ryskina, Antonio P Legorreta, Deborah A Taira, Richard S ChungAbstract:Within the past decade, several Institute of Medicine (IOM) reports have recommended quality-based incentive programs as effective tools to improve quality of care (Kohn, Corrigan, and Donaldson 2000; IOM 2001; Corrigan, Eden, and Smith 2002). In response, many health plans, as well as the Centers for Medicare and Medicaid Services (CMS), have turned their focus to measures that evaluate physician performance in various aspects of care quality such as patient satisfaction and processes of care (CMS 2003; Casalino et al. 2003; Webber 2005). While the programs have produced an abundance of anecdotal evidence suggesting that performance-based reimbursement can affect physician behavior (Morrow, Gooding, and Clark 1995; Fairbrother et al. 1999; Forsberg, Axelsson, and Arnetz 2001; Amundson et al. 2003; Roski et al. 2003), the majority of the programs were implemented in a health maintenance organization (HMO) setting (Levin-Scherz, DeVita, and Timbie 2005; Rosenthal et al. 2005), where evaluation of physician adherence to clinical guidelines is easier to make (Sommers and Wholey 2003), compared with a preferred Provider organization (PPO) setting, where responsibility for patient care is more likely to be shared between multiple physicians because patients have freedom to see Providers without referral. In addition, HMO plans are more likely to have systematic interventions to improve care processes and outcomes, such as reminders, benefit coverage for screenings, and disease management programs (Casalino et al. 2003), which may contribute to increased adherence to guidelines (Carlisle et al. 1992; Merrill et al. 1999). On the other hand, compared with capitated Provider reimbursement in HMO plans, reimbursement arrangements in PPO plans may be better aligned with incentive programs aimed at improving compliance with guidelines that encourage appropriate utilization of certain Services (e.g., follow-up, laboratory test, etc.), where base compensation and incentive bonus share common direction (Dudley 2005). Because PPO structure poses multiple challenges to measurement of Provider Service quality, the effectiveness of incentive programs on quality of care in a PPO setting has been less rigorously studied despite the increasing role of PPOs as the plan of choice in the United States (Hellinger 1998). This study expands upon the current literature by evaluating the quality of care provided by physicians who participated in a novel PPO-based quality incentive program executed by a large nonprofit health plan in Hawaii. We examined whether the quality of care received by patients who visited only physicians who participated in the incentive program improved over a 6-year period compared with patients who visited only physicians who did not participate in the program.
