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Sample records for management efficient scheme

  1. A High Fuel Consumption Efficiency Management Scheme for PHEVs Using an Adaptive Genetic Algorithm

    PubMed Central

    Lee, Wah Ching; Tsang, Kim Fung; Chi, Hao Ran; Hung, Faan Hei; Wu, Chung Kit; Chui, Kwok Tai; Lau, Wing Hong; Leung, Yat Wah

    2015-01-01

    A high fuel efficiency management scheme for plug-in hybrid electric vehicles (PHEVs) has been developed. In order to achieve fuel consumption reduction, an adaptive genetic algorithm scheme has been designed to adaptively manage the energy resource usage. The objective function of the genetic algorithm is implemented by designing a fuzzy logic controller which closely monitors and resembles the driving conditions and environment of PHEVs, thus trading off between petrol versus electricity for optimal driving efficiency. Comparison between calculated results and publicized data shows that the achieved efficiency of the fuzzified genetic algorithm is better by 10% than existing schemes. The developed scheme, if fully adopted, would help reduce over 600 tons of CO2 emissions worldwide every day. PMID:25587974

  2. An efficient key-management scheme for hierarchical access control in e-medicine system.

    PubMed

    Wu, Shuhua; Chen, Kefei

    2012-08-01

    In e-medicine system, the sharing of patients' medical histories scattered among medical institutions through the Internet is highly desirable. The most immediate cryptographic need certainly is an efficient key management method to solve dynamic access problems in a user hierarchy. In this paper, we propose a practical solution for dynamic access problem in a user hierarchy based on hybrid cryptosystems. When compared with Nikooghadam et al.'s scheme proposed most recently, the time complexity and the required storage space is reduced significantly. Moreover, it provides provable security, and is easy to implement. Therefore, our scheme is more suitable for e-medicine system.

  3. An efficient identity-based key management scheme for wireless sensor networks using the Bloom filter.

    PubMed

    Qin, Zhongyuan; Zhang, Xinshuai; Feng, Kerong; Zhang, Qunfang; Huang, Jie

    2014-09-26

    With the rapid development and widespread adoption of wireless sensor networks (WSNs), security has become an increasingly prominent problem. How to establish a session key in node communication is a challenging task for WSNs. Considering the limitations in WSNs, such as low computing capacity, small memory, power supply limitations and price, we propose an efficient identity-based key management (IBKM) scheme, which exploits the Bloom filter to authenticate the communication sensor node with storage efficiency. The security analysis shows that IBKM can prevent several attacks effectively with acceptable computation and communication overhead.

  4. An Efficient Identity-Based Key Management Scheme for Wireless Sensor Networks Using the Bloom Filter

    PubMed Central

    Qin, Zhongyuan; Zhang, Xinshuai; Feng, Kerong; Zhang, Qunfang; Huang, Jie

    2014-01-01

    With the rapid development and widespread adoption of wireless sensor networks (WSNs), security has become an increasingly prominent problem. How to establish a session key in node communication is a challenging task for WSNs. Considering the limitations in WSNs, such as low computing capacity, small memory, power supply limitations and price, we propose an efficient identity-based key management (IBKM) scheme, which exploits the Bloom filter to authenticate the communication sensor node with storage efficiency. The security analysis shows that IBKM can prevent several attacks effectively with acceptable computation and communication overhead. PMID:25264955

  5. Modeling and Analysis of an Energy-Efficient Mobility Management Scheme in IP-Based Wireless Networks†

    PubMed Central

    Hwang, Ho Young; Kwon, Sun-Jong; Chung, Yun Won; Sung, Dan Keun; Park, Suwon

    2011-01-01

    An energy-efficient mobility management scheme in IP-based wireless networks is proposed to reduce the battery power consumption of mobile hosts (MHs). The proposed scheme manages seven MH states, including transmitting, receiving, attention/cell-connected, attention/paging area(PA)-connected, idle, off/attached, and detached states, to efficiently manage battery power, radio resources, and network load. We derive the stationary probabilities and steady state probabilities of the seven MH states for the proposed scheme in IP-based wireless networks in compact form. The effects of various input parameters on MH steady state probabilities and power consumption are investigated in the proposed scheme compared to the conventional scheme. Network costs such as cell updates, PA updates, binding-lifetime-based registrations, and paging messages are analyzed in the proposed and conventional schemes. The optimal values of PA size and registration interval are derived to minimize the network cost of the proposed scheme. The combined network and power costs are investigated for the proposed and conventional schemes. The results provide guidelines to select the proper system parameters in IP-based wireless networks. PMID:22247665

  6. Modeling and analysis of an energy-efficient mobility management scheme in IP-based wireless networks.

    PubMed

    Hwang, Ho Young; Kwon, Sun-Jong; Chung, Yun Won; Sung, Dan Keun; Park, Suwon

    2011-01-01

    An energy-efficient mobility management scheme in IP-based wireless networks is proposed to reduce the battery power consumption of mobile hosts (MHs). The proposed scheme manages seven MH states, including transmitting, receiving, attention/cell-connected, attention/paging area(PA)-connected, idle, off/attached, and detached states, to efficiently manage battery power, radio resources, and network load. We derive the stationary probabilities and steady state probabilities of the seven MH states for the proposed scheme in IP-based wireless networks in compact form. The effects of various input parameters on MH steady state probabilities and power consumption are investigated in the proposed scheme compared to the conventional scheme. Network costs such as cell updates, PA updates, binding-lifetime-based registrations, and paging messages are analyzed in the proposed and conventional schemes. The optimal values of PA size and registration interval are derived to minimize the network cost of the proposed scheme. The combined network and power costs are investigated for the proposed and conventional schemes. The results provide guidelines to select the proper system parameters in IP-based wireless networks.

  7. An Energy-Efficient Secure Routing and Key Management Scheme for Mobile Sinks in Wireless Sensor Networks Using Deployment Knowledge.

    PubMed

    Hung, Le Xuan; Canh, Ngo Trong; Lee, Sungyoung; Lee, Young-Koo; Lee, Heejo

    2008-12-03

    For many sensor network applications such as military or homeland security, it is essential for users (sinks) to access the sensor network while they are moving. Sink mobility brings new challenges to secure routing in large-scale sensor networks. Previous studies on sink mobility have mainly focused on efficiency and effectiveness of data dissemination without security consideration. Also, studies and experiences have shown that considering security during design time is the best way to provide security for sensor network routing. This paper presents an energy-efficient secure routing and key management for mobile sinks in sensor networks, called SCODEplus. It is a significant extension of our previous study in five aspects: (1) Key management scheme and routing protocol are considered during design time to increase security and efficiency; (2) The network topology is organized in a hexagonal plane which supports more efficiency than previous square-grid topology; (3) The key management scheme can eliminate the impacts of node compromise attacks on links between non-compromised nodes; (4) Sensor node deployment is based on Gaussian distribution which is more realistic than uniform distribution; (5) No GPS or like is required to provide sensor node location information. Our security analysis demonstrates that the proposed scheme can defend against common attacks in sensor networks including node compromise attacks, replay attacks, selective forwarding attacks, sinkhole and wormhole, Sybil attacks, HELLO flood attacks. Both mathematical and simulation-based performance evaluation show that the SCODEplus significantly reduces the communication overhead, energy consumption, packet delivery latency while it always delivers more than 97 percent of packets successfully.

  8. An Energy-Efficient Secure Routing and Key Management Scheme for Mobile Sinks in Wireless Sensor Networks Using Deployment Knowledge

    PubMed Central

    Hung, Le Xuan; Canh, Ngo Trong; Lee, Sungyoung; Lee, Young-Koo; Lee, Heejo

    2008-01-01

    For many sensor network applications such as military or homeland security, it is essential for users (sinks) to access the sensor network while they are moving. Sink mobility brings new challenges to secure routing in large-scale sensor networks. Previous studies on sink mobility have mainly focused on efficiency and effectiveness of data dissemination without security consideration. Also, studies and experiences have shown that considering security during design time is the best way to provide security for sensor network routing. This paper presents an energy-efficient secure routing and key management for mobile sinks in sensor networks, called SCODEplus. It is a significant extension of our previous study in five aspects: (1) Key management scheme and routing protocol are considered during design time to increase security and efficiency; (2) The network topology is organized in a hexagonal plane which supports more efficiency than previous square-grid topology; (3) The key management scheme can eliminate the impacts of node compromise attacks on links between non-compromised nodes; (4) Sensor node deployment is based on Gaussian distribution which is more realistic than uniform distribution; (5) No GPS or like is required to provide sensor node location information. Our security analysis demonstrates that the proposed scheme can defend against common attacks in sensor networks including node compromise attacks, replay attacks, selective forwarding attacks, sinkhole and wormhole, Sybil attacks, HELLO flood attacks. Both mathematical and simulation-based performance evaluation show that the SCODEplus significantly reduces the communication overhead, energy consumption, packet delivery latency while it always delivers more than 97 percent of packets successfully. PMID:27873956

  9. How much are people willing to pay for efficient waste management schemes? A benefit transfer application.

    PubMed

    Damigos, Dimitris; Kaliampakos, Dimitris; Menegaki, Maria

    2016-04-01

    To socially justify the need for better municipal solid waste management services, especially in the light of the limited availability of public funds, it is important to quantify the monetary value of the potential social and environmental benefits offered by them. This article aims at estimating society's willingness to pay improved municipal solid waste management and establishing suitable reference values using the 'benefit transfer' method. To this direction, relevant studies from the global scientific and grey literature in the field of municipal solid waste management valuation are analysed and two different transfer approaches are implemented. According to the analysis, the mean annual willingness to pay per household is 88.4 USD(2014) (5%-trimmed mean: 78.7 USD(2014); 95% confidence interval lower bound: 64.8 USD(2014) and upper bound: 112.0 USD(2014)). The analysis yields estimates with a high standard deviation and notably broad confidence intervals, owing to design issues of the primary studies, the different socioeconomic profiles of the populations surveyed and the existing level of municipal solid waste management services. Thus, a meta-regression model is estimated to explore the sources of heterogeneity and facilitate more accurate transfer values. Nevertheless, the limited number of observations and some methodological issues in the design and conduct of the original surveys set certain challenges and increase the level of uncertainty of the transfer values. © The Author(s) 2016.

  10. A novel key management scheme using biometrics

    NASA Astrophysics Data System (ADS)

    Sui, Yan; Yang, Kai; Du, Yingzi; Orr, Scott; Zou, Xukai

    2010-04-01

    Key management is one of the most important issues in cryptographic systems. Several important challenges in such a context are represented by secure and efficient key generation, key distribution, as well as key revocation. Addressing such challenges requires a comprehensive solution which is robust, secure and efficient. Compared to traditional key management schemes, key management using biometrics requires the presence of the user, which can reduce fraud and protect the key better. In this paper, we propose a novel key management scheme using iris based biometrics. Our newly proposed scheme outperforms traditional key management schemes as well as some existing key-binding biometric schemes in terms of security, diversity and/or efficiency.

  11. Efficient DSMC collision-partner selection schemes.

    SciTech Connect

    Gallis, Michail A.; Torczynski, John Robert

    2010-05-01

    The effect of collision-partner selection schemes on the accuracy and the efficiency of the Direct Simulation Monte Carlo (DSMC) method of Bird is investigated. Several schemes to reduce the total discretization error as a function of the mean collision separation and the mean collision time are examined. These include the historically first sub-cell scheme, the more recent nearest-neighbor scheme, and various near-neighbor schemes, which are evaluated for their effect on the thermal conductivity for Fourier flow. Their convergence characteristics as a function of spatial and temporal discretization and the number of simulators per cell are compared to the convergence characteristics of the sophisticated and standard DSMC algorithms. Improved performance is obtained if the population from which possible collision partners are selected is an appropriate fraction of the population of the cell.

  12. Efficient DSMC collision-partner selection schemes.

    SciTech Connect

    Gallis, Michail A.; Torczynski, John Robert

    2010-07-01

    The effect of collision-partner selection schemes on the accuracy and the efficiency of the Direct Simulation Monte Carlo (DSMC) method of Bird is investigated. Several schemes to reduce the total discretization error as a function of the mean collision separation and the mean collision time are examined. These include the historically first sub-cell scheme, the more recent nearest-neighbor scheme, and various near-neighbor schemes, which are evaluated for their effect on the thermal conductivity for Fourier flow. Their convergence characteristics as a function of spatial and temporal discretization and the number of simulators per cell are compared to the convergence characteristics of the sophisticated and standard DSMC algorithms. Improved performance is obtained if the population from which possible collision partners are selected is an appropriate fraction of the population of the cell.

  13. Efficient multiparty quantum-secret-sharing schemes

    SciTech Connect

    Xiao Li; Deng Fuguo; Long Guilu; Pan Jianwei

    2004-05-01

    In this work, we generalize the quantum-secret-sharing scheme of Hillery, Buzek, and Berthiaume [Phys. Rev. A 59, 1829 (1999)] into arbitrary multiparties. Explicit expressions for the shared secret bit is given. It is shown that in the Hillery-Buzek-Berthiaume quantum-secret-sharing scheme the secret information is shared in the parity of binary strings formed by the measured outcomes of the participants. In addition, we have increased the efficiency of the quantum-secret-sharing scheme by generalizing two techniques from quantum key distribution. The favored-measuring-basis quantum-secret-sharing scheme is developed from the Lo-Chau-Ardehali technique [H. K. Lo, H. F. Chau, and M. Ardehali, e-print quant-ph/0011056] where all the participants choose their measuring-basis asymmetrically, and the measuring-basis-encrypted quantum-secret-sharing scheme is developed from the Hwang-Koh-Han technique [W. Y. Hwang, I. G. Koh, and Y. D. Han, Phys. Lett. A 244, 489 (1998)] where all participants choose their measuring basis according to a control key. Both schemes are asymptotically 100% in efficiency, hence nearly all the Greenberger-Horne-Zeilinger states in a quantum-secret-sharing process are used to generate shared secret information.

  14. Efficient Conservative Reformulation Schemes for Lithium Intercalation

    SciTech Connect

    Urisanga, PC; Rife, D; De, S; Subramanian, VR

    2015-02-18

    Porous electrode theory coupled with transport and reaction mechanisms is a widely used technique to model Li-ion batteries employing an appropriate discretization or approximation for solid phase diffusion with electrode particles. One of the major difficulties in simulating Li-ion battery models is the need to account for solid phase diffusion in a second radial dimension r, which increases the computation time/cost to a great extent. Various methods that reduce the computational cost have been introduced to treat this phenomenon, but most of them do not guarantee mass conservation. The aim of this paper is to introduce an inherently mass conserving yet computationally efficient method for solid phase diffusion based on Lobatto III A quadrature. This paper also presents coupling of the new solid phase reformulation scheme with a macro-homogeneous porous electrode theory based pseudo 20 model for Li-ion battery. (C) The Author(s) 2015. Published by ECS. All rights reserved.

  15. An efficient training scheme for supermodels

    NASA Astrophysics Data System (ADS)

    Schevenhoven, Francine J.; Selten, Frank M.

    2017-06-01

    Weather and climate models have improved steadily over time as witnessed by objective skill scores, although significant model errors remain. Given these imperfect models, predictions might be improved by combining them dynamically into a so-called supermodel. In this paper a new training scheme to construct such a supermodel is explored using a technique called cross pollination in time (CPT). In the CPT approach the models exchange states during the prediction. The number of possible predictions grows quickly with time, and a strategy to retain only a small number of predictions, called pruning, needs to be developed. The method is explored using low-order dynamical systems and applied to a global atmospheric model. The results indicate that the CPT training is efficient and leads to a supermodel with improved forecast quality as compared to the individual models. Due to its computational efficiency, the technique is suited for application to state-of-the art high-dimensional weather and climate models.

  16. An efficient compression scheme for bitmap indices

    SciTech Connect

    Wu, Kesheng; Otoo, Ekow J.; Shoshani, Arie

    2004-04-13

    When using an out-of-core indexing method to answer a query, it is generally assumed that the I/O cost dominates the overall query response time. Because of this, most research on indexing methods concentrate on reducing the sizes of indices. For bitmap indices, compression has been used for this purpose. However, in most cases, operations on these compressed bitmaps, mostly bitwise logical operations such as AND, OR, and NOT, spend more time in CPU than in I/O. To speedup these operations, a number of specialized bitmap compression schemes have been developed; the best known of which is the byte-aligned bitmap code (BBC). They are usually faster in performing logical operations than the general purpose compression schemes, but, the time spent in CPU still dominates the total query response time. To reduce the query response time, we designed a CPU-friendly scheme named the word-aligned hybrid (WAH) code. In this paper, we prove that the sizes of WAH compressed bitmap indices are about two words per row for large range of attributes. This size is smaller than typical sizes of commonly used indices, such as a B-tree. Therefore, WAH compressed indices are not only appropriate for low cardinality attributes but also for high cardinality attributes.In the worst case, the time to operate on compressed bitmaps is proportional to the total size of the bitmaps involved. The total size of the bitmaps required to answer a query on one attribute is proportional to the number of hits. These indicate that WAH compressed bitmap indices are optimal. To verify their effectiveness, we generated bitmap indices for four different datasets and measured the response time of many range queries. Tests confirm that sizes of compressed bitmap indices are indeed smaller than B-tree indices, and query processing with WAH compressed indices is much faster than with BBC compressed indices, projection indices and B-tree indices. In addition, we also verified that the average query response time

  17. Efficient implementation of weighted ENO schemes

    NASA Technical Reports Server (NTRS)

    Jiang, Guang-Shan; Shu, Chi-Wang

    1995-01-01

    In this paper, we further analyze, test, modify and improve the high order WENO (weighted essentially non-oscillatory) finite difference schemes of Liu, Osher and Chan. It was shown by Liu et al. that WENO schemes constructed from the r-th order (in L1 norm) ENO schemes are (r+1)-th order accurate. We propose a new way of measuring the smoothness of a numerical solution, emulating the idea of minimizing the total variation of the approximation, which results in a 5-th order WENO scheme for the case r = 3, instead of the 4-th order with the original smoothness measurement by Liu et al. This 5-th order WENO scheme is as fast as the 4-th order WENO scheme of Liu et al., and both schemes are about twice as fast as the 4-th order ENO schemes on vector supercomputers and as fast on serial and parallel computers. For Euler systems of gas dynamics, we suggest computing the weights from pressure and entropy instead of the characteristic values to simplify the costly characteristic procedure. The resulting WENO schemes are about twice as fast as the WENO schemes using the characteristic decompositions to compute weights, and work well for problems which do not contain strong shocks or strong reflected waves. We also prove that, for conservation laws with smooth solutions, all WENO schemes are convergent. Many numerical tests, including the 1D steady state nozzle flow problem and 2D shock entropy wave interaction problem, are presented to demonstrate the remarkable capability of the WENO schemes, especially the WENO scheme using the new smoothness measurement, in resolving complicated shock and flow structures. We have also applied Yang's artificial compression method to the WENO schemes to sharpen contact discontinuities.

  18. Efficient lossless compression scheme for multispectral images

    NASA Astrophysics Data System (ADS)

    Benazza-Benyahia, Amel; Hamdi, Mohamed; Pesquet, Jean-Christophe

    2001-12-01

    Huge amounts of data are generated thanks to the continuous improvement of remote sensing systems. Archiving this tremendous volume of data is a real challenge which requires lossless compression techniques. Furthermore, progressive coding constitutes a desirable feature for telebrowsing. To this purpose, a compact and pyramidal representation of the input image has to be generated. Separable multiresolution decompositions have already been proposed for multicomponent images allowing each band to be decomposed separately. It seems however more appropriate to exploit also the spectral correlations. For hyperspectral images, the solution is to apply a 3D decomposition according to the spatial and to the spectral dimensions. This approach is not appropriate for multispectral images because of the reduced number of spectral bands. In recent works, we have proposed a nonlinear subband decomposition scheme with perfect reconstruction which exploits efficiently both the spatial and the spectral redundancies contained in multispectral images. In this paper, the problem of coding the coefficients of the resulting subband decomposition is addressed. More precisely, we propose an extension to the vector case of Shapiro's embedded zerotrees of wavelet coefficients (V-EZW) with achieves further saving in the bit stream. Simulations carried out on SPOT images indicate the outperformance of the global compression package we performed.

  19. Secure SCADA communication by using a modified key management scheme.

    PubMed

    Rezai, Abdalhossein; Keshavarzi, Parviz; Moravej, Zahra

    2013-07-01

    This paper presents and evaluates a new cryptographic key management scheme which increases the efficiency and security of the Supervisory Control And Data Acquisition (SCADA) communication. In the proposed key management scheme, two key update phases are used: session key update and master key update. In the session key update phase, session keys are generated in the master station. In the master key update phase, the Elliptic Curve Diffie-Hellman (ECDH) protocol is used. The Poisson process is also used to model the Security Index (SI) and Quality of Service (QoS). Our analysis shows that the proposed key management not only supports the required speed in the MODBUS implementation but also has several advantages compared to other key management schemes for secure communication in SCADA networks. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

  20. An efficient and provably secure proxy signature scheme

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhong; Liu, Xue; Gao, Shengnan

    2010-08-01

    Proxy signature is a special signature, it allows an original signer to delegate her signing capability to a proxy signer and the proxy signer can produce a signature on behalf of the original signer. At present, most of proxy signature in essence consists of two signatures. To overcome the problem, we propose a short efficient proxy signature scheme based on a certificateless signature scheme. And we show that the proposed scheme is secure in the random oracle model. The security of the scheme is related to Inverse Computational Diffie-Hellman Problem and the k-CCA problem. Comparison with Huang et.al scheme, our scheme has an advantage over Huang et.al's scheme in terms of the size of proxy signature. Since the length of proxy signature in our scheme is 160bit, it is very suitable for mobile devices.

  1. Efficient Unrestricted Identity-Based Aggregate Signature Scheme

    PubMed Central

    Yuan, Yumin; Zhan, Qian; Huang, Hua

    2014-01-01

    An aggregate signature scheme allows anyone to compress multiple individual signatures from various users into a single compact signature. The main objective of such a scheme is to reduce the costs on storage, communication and computation. However, among existing aggregate signature schemes in the identity-based setting, some of them fail to achieve constant-length aggregate signature or require a large amount of pairing operations which grows linearly with the number of signers, while others have some limitations on the aggregated signatures. The main challenge in building efficient aggregate signature scheme is to compress signatures into a compact, constant-length signature without any restriction. To address the above drawbacks, by using the bilinear pairings, we propose an efficient unrestricted identity-based aggregate signature. Our scheme achieves both full aggregation and constant pairing computation. We prove that our scheme has existential unforgeability under the computational Diffie-Hellman assumption. PMID:25329777

  2. Efficient unrestricted identity-based aggregate signature scheme.

    PubMed

    Yuan, Yumin; Zhan, Qian; Huang, Hua

    2014-01-01

    An aggregate signature scheme allows anyone to compress multiple individual signatures from various users into a single compact signature. The main objective of such a scheme is to reduce the costs on storage, communication and computation. However, among existing aggregate signature schemes in the identity-based setting, some of them fail to achieve constant-length aggregate signature or require a large amount of pairing operations which grows linearly with the number of signers, while others have some limitations on the aggregated signatures. The main challenge in building efficient aggregate signature scheme is to compress signatures into a compact, constant-length signature without any restriction. To address the above drawbacks, by using the bilinear pairings, we propose an efficient unrestricted identity-based aggregate signature. Our scheme achieves both full aggregation and constant pairing computation. We prove that our scheme has existential unforgeability under the computational Diffie-Hellman assumption.

  3. Payment schemes and cost efficiency: evidence from Swiss public hospitals.

    PubMed

    Meyer, Stefan

    2015-03-01

    This paper aims at analysing the impact of prospective payment schemes on cost efficiency of acute care hospitals in Switzerland. We study a panel of 121 public hospitals subject to one of four payment schemes. While several hospitals are still reimbursed on a per diem basis for the treatment of patients, most face flat per-case rates-or mixed schemes, which combine both elements of reimbursement. Thus, unlike previous studies, we are able to simultaneously analyse and isolate the cost-efficiency effects of different payment schemes. By means of stochastic frontier analysis, we first estimate a hospital cost frontier. Using the two-stage approach proposed by Battese and Coelli (Empir Econ 20:325-332, 1995), we then analyse the impact of these payment schemes on the cost efficiency of hospitals. Controlling for hospital characteristics, local market conditions in the 26 Swiss states (cantons), and a time trend, we show that, compared to per diem, hospitals which are reimbursed by flat payment schemes perform better in terms of cost efficiency. Our results suggest that mixed schemes create incentives for cost containment as well, although to a lesser extent. In addition, our findings indicate that cost-efficient hospitals are primarily located in cantons with competitive markets, as measured by the Herfindahl-Hirschman index in inpatient care. Furthermore, our econometric model shows that we obtain biased estimates from frontier analysis if we do not account for heteroscedasticity in the inefficiency term.

  4. A Secure and Efficient Threshold Group Signature Scheme

    NASA Astrophysics Data System (ADS)

    Zhang, Yansheng; Wang, Xueming; Qiu, Gege

    The paper presents a secure and efficient threshold group signature scheme aiming at two problems of current threshold group signature schemes: conspiracy attack and inefficiency. Scheme proposed in this paper takes strategy of separating designed clerk who is responsible for collecting and authenticating each individual signature from group, the designed clerk don't participate in distribution of group secret key and has his own public key and private key, designed clerk needs to sign part information of threshold group signature after collecting signatures. Thus verifier has to verify signature of the group after validating signature of the designed clerk. This scheme is proved to be secure against conspiracy attack at last and is more efficient by comparing with other schemes.

  5. An Efficient Remote Authentication Scheme for Wireless Body Area Network.

    PubMed

    Omala, Anyembe Andrew; Kibiwott, Kittur P; Li, Fagen

    2017-02-01

    Wireless body area network (WBAN) provide a mechanism of transmitting a persons physiological data to application providers e.g. hospital. Given the limited range of connectivity associated with WBAN, an intermediate portable device e.g. smartphone, placed within WBAN's connectivity, forwards the data to a remote server. This data, if not protected from an unauthorized access and modification may be lead to poor diagnosis. In order to ensure security and privacy between WBAN and a server at the application provider, several authentication schemes have been proposed. Recently, Wang and Zhang proposed an authentication scheme for WBAN using bilinear pairing. However, in their scheme, an application provider could easily impersonate a client. In order to overcome this weakness, we propose an efficient remote authentication scheme for WBAN. In terms of performance, our scheme can not only provide a malicious insider security, but also reduce running time of WBAN (client) by 51 % as compared to Wang and Zhang scheme.

  6. Hybrid Cluster Mesh Scheme for Energy Efficient Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Lee, Sungil; Lim, Jaesung

    Wireless Sensor Networks (WSNs) have become a key technology for ubiquitous computing environments. In WSNs, battery recharge or replacement is impossible because sensors are left unattended after deployment. Therefore, WSNs need a networking protocol scheme to increase the life time of sensor nodes. The clustering technique is an efficient approach for reducing energy consumption in wireless sensor networks. In cluster topology, however, there is a problem which causes a large amount of energy consumption of cluster head. In addition, in the sparsely deployed sensor field, mesh topology can be more energy-efficient than cluster topology. In this paper, we propose a Hybrid Cluster Mesh (HCM) scheme, which recognizes the density of neighbor nodes and each node decides its topology itself, and HCM-RO (reorganization) scheme which reorganizes clusters. Simulation results show that the proposed hybrid topology control scheme is more energy-efficient than each topology of cluster or mesh.

  7. An efficient class of WENO schemes with adaptive order

    NASA Astrophysics Data System (ADS)

    Balsara, Dinshaw S.; Garain, Sudip; Shu, Chi-Wang

    2016-12-01

    Finite difference WENO schemes have established themselves as very worthy performers for entire classes of applications that involve hyperbolic conservation laws. In this paper we report on two major advances that make finite difference WENO schemes more efficient. The first advance consists of realizing that WENO schemes require us to carry out stencil operations very efficiently. In this paper we show that the reconstructed polynomials for any one-dimensional stencil can be expressed most efficiently and economically in Legendre polynomials. By using Legendre basis, we show that the reconstruction polynomials and their corresponding smoothness indicators can be written very compactly. The smoothness indicators are written as a sum of perfect squares. Since this is a computationally expensive step, the efficiency of finite difference WENO schemes is enhanced by the innovation which is reported here. The second advance consists of realizing that one can make a non-linear hybridization between a large, centered, very high accuracy stencil and a lower order WENO scheme that is nevertheless very stable and capable of capturing physically meaningful extrema. This yields a class of adaptive order WENO schemes, which we call WENO-AO (for adaptive order). Thus we arrive at a WENO-AO(5,3) scheme that is at best fifth order accurate by virtue of its centered stencil with five zones and at worst third order accurate by virtue of being non-linearly hybridized with an r = 3 CWENO scheme. The process can be extended to arrive at a WENO-AO(7,3) scheme that is at best seventh order accurate by virtue of its centered stencil with seven zones and at worst third order accurate. We then recursively combine the above two schemes to arrive at a WENO-AO(7,5,3) scheme which can achieve seventh order accuracy when that is possible; graciously drop down to fifth order accuracy when that is the best one can do; and also operate stably with an r = 3 CWENO scheme when that is the only thing

  8. Improved-efficiency DSMC collision-partner selection schemes.

    SciTech Connect

    Gallis, Michail A.; Torczynski, John Robert

    2010-11-01

    The effect of collision-partner selection schemes on the accuracy and the efficiency of the Direct Simulation Monte Carlo (DSMC) method of Bird is investigated. Several schemes to reduce the total discretization error as a function of the mean collision separation and the mean collision time are examined. These include the historically first sub-cell scheme, the more recent nearest-neighbor scheme, and various near-neighbor schemes, which are evaluated for their effect on the thermal conductivity for Fourier flow. Their convergence characteristics as a function of spatial and temporal discretization and the number of simulators per cell are compared to the convergence characteristics of the sophisticated and standard DSMC algorithms. Improved performance is obtained if the population from which possible collision partners are selected is an appropriate fraction of the population of the cell.

  9. Efficient ARQ schemes for error control of satellite channels

    NASA Astrophysics Data System (ADS)

    Fantacci, Romano

    1989-09-01

    In this paper, the performance of some efficient ARQ schemes which make use of repeated transmissions of the same data block and compound detection are analyzed. The repeated transmission of the same data block involves repeated transmission of each symbol of the data block. At the receiving end, compound detection formed of a soft detection jointly with a classical hard detection is performed by using all the received copies of the same symbol. The throughput efficiencies for the proposed ARQ schemes are analytically derived in closed form and optimized with respect to the number of copies to be transmitted for each data block. It will be shown that the optimized ARQ schemes proposed in this paper achieve better performance than classical ARQ schemes, in particular under high error rate conditions.

  10. An Efficient Scheme for Updating Sparse Cholesky Factors

    NASA Technical Reports Server (NTRS)

    Raghavan, Padma

    2002-01-01

    Raghavan had earlier developed the software package DCSPACK which can be used for solving sparse linear systems where the coefficient matrix is symmetric and positive definite (this project was not funded by NASA but by agencies such as NSF). DSCPACK-S is the serial code and DSCPACK-P is a parallel implementation suitable for multiprocessors or networks-of-workstations with message passing using MCI. The main algorithm used is the Cholesky factorization of a sparse symmetric positive positive definite matrix A = LL(T). The code can also compute the factorization A = LDL(T). The complexity of the software arises from several factors relating to the sparsity of the matrix A. A sparse N x N matrix A has typically less that cN nonzeroes where c is a small constant. If the matrix were dense, it would have O(N2) nonzeroes. The most complicated part of such sparse Cholesky factorization relates to fill-in, i.e., zeroes in the original matrix that become nonzeroes in the factor L. An efficient implementation depends to a large extent on complex data structures and on techniques from graph theory to reduce, identify, and manage fill. DSCPACK is based on an efficient multifrontal implementation with fill-managing algorithms and implementation arising from earlier research by Raghavan and others. Sparse Cholesky factorization is typically a four step process: (1) ordering to compute a fill-reducing numbering, (2) symbolic factorization to determine the nonzero structure of L, (3) numeric factorization to compute L, and, (4) triangular solution to solve L(T)x = y and Ly = b. The first two steps are symbolic and are performed using the graph of the matrix. The numeric factorization step is of dominant cost and there are several schemes for improving performance by exploiting the nested and dense structure of groups of columns in the factor. The latter are aimed at better utilization of the cache-memory hierarchy on modem processors to prevent cache-misses and provide execution

  11. Efficient ARQ scheme for high error rate channels

    NASA Astrophysics Data System (ADS)

    Moeneclaey, M.; Bruneel, H.

    1984-11-01

    A continuous error detection and retransmission (ARQ) protocol which preserves the order of the data block is presented. Data blocks are retransmitted continuously until a positive acknowledgement is received. The next block is then transmitted. It is shown that in high error rate conditions, i.e., the probability of message error is greater than 0.5, the scheme is more efficient than go-back-N and selective repeat schemes. The high error rates increase with the length of propagation delays.

  12. Compound management beyond efficiency.

    PubMed

    Burr, Ian; Winchester, Toby; Keighley, Wilma; Sewing, Andreas

    2009-06-01

    Codeveloping alongside chemistry and in vitro screening, compound management was one of the first areas in research recognizing the need for efficient processes and workflows. Material management groups have centralized, automated, miniaturized and, importantly, found out what not to do with compounds. While driving down cost and improving quality in storage and processing, researchers still face the challenge of interfacing optimally with changing business processes, in screening groups, and with external vendors and focusing on biologicals in many companies. Here we review our strategy to provide a seamless link between compound acquisition and screening operations and the impact of material management on quality of the downstream processes. Although this is driven in part by new technologies and improved quality control within material management, redefining team structures and roles also drives job satisfaction and motivation in our teams with a subsequent positive impact on cycle times and customer feedback.

  13. Efficient scheme for parametric fitting of data in arbitrary dimensions.

    PubMed

    Pang, Ning-Ning; Tzeng, Wen-Jer; Kao, Hisen-Ching

    2008-07-01

    We propose an efficient scheme for parametric fitting expressed in terms of the Legendre polynomials. For continuous systems, our scheme is exact and the derived explicit expression is very helpful for further analytical studies. For discrete systems, our scheme is almost as accurate as the method of singular value decomposition. Through a few numerical examples, we show that our algorithm costs much less CPU time and memory space than the method of singular value decomposition. Thus, our algorithm is very suitable for a large amount of data fitting. In addition, the proposed scheme can also be used to extract the global structure of fluctuating systems. We then derive the exact relation between the correlation function and the detrended variance function of fluctuating systems in arbitrary dimensions and give a general scaling analysis.

  14. Performance of the efficient data-driven evaluation scheme

    SciTech Connect

    Johnson, D.; Berman, F. . Dept. of Computer Science and Engineering)

    1993-07-01

    The Efficient Data-Driven Evaluation Scheme is a two-phase strategy for optimizing the execution time of programs in the IF1 dataflow format. The first phase involves adding extra nodes and edges to the IF1 program graph at compile-time. In the second phase, the new nodes and edges facilitate the determination of useless computations (i.e., computations which do not contribute to the final results) at run-time and prevent these computations from being executed. By focusing on the execution of potentially useful computations, architectural models with limited processors can be used more effectively, and execution times may be reduced. In this paper, the authors briefly review the Efficient Data-Driven Evaluation Scheme and describe performance results of the scheme on a large set of benchmarks which include the Livermore Loops. Their experiments compare the Efficient Data-Driven Evaluation Scheme to eager and lazy compilation for these benchmarks and characterized programs for which their scheme may be used effectively as a computer optimization.

  15. Cost efficient command management

    NASA Technical Reports Server (NTRS)

    Brandt, Theresa; Murphy, C. W.; Kuntz, Jon; Barlett, Tom

    1996-01-01

    The design and implementation of a command management system (CMS) for a NASA control center, is described. The technology innovations implemented in the CMS provide the infrastructure required for operations cost reduction and future development cost reduction through increased operational efficiency and reuse in future missions. The command management design facilitates error-free operations which enables the automation of the routine control center functions and allows for the distribution of scheduling responsibility to the instrument teams. The reusable system was developed using object oriented methodologies.

  16. An Efficient Variable Length Coding Scheme for an IID Source

    NASA Technical Reports Server (NTRS)

    Cheung, K. -M.

    1995-01-01

    A scheme is examined for using two alternating Huffman codes to encode a discrete independent and identically distributed source with a dominant symbol. This combined strategy, or alternating runlength Huffman (ARH) coding, was found to be more efficient than ordinary coding in certain circumstances.

  17. A fast and efficient segmentation scheme for cell microscopic image.

    PubMed

    Lebrun, G; Charrier, C; Lezoray, O; Meurie, C; Cardot, H

    2007-04-27

    Microscopic cellular image segmentation schemes must be efficient for reliable analysis and fast to process huge quantity of images. Recent studies have focused on improving segmentation quality. Several segmentation schemes have good quality but processing time is too expensive to deal with a great number of images per day. For segmentation schemes based on pixel classification, the classifier design is crucial since it is the one which requires most of the processing time necessary to segment an image. The main contribution of this work is focused on how to reduce the complexity of decision functions produced by support vector machines (SVM) while preserving recognition rate. Vector quantization is used in order to reduce the inherent redundancy present in huge pixel databases (i.e. images with expert pixel segmentation). Hybrid color space design is also used in order to improve data set size reduction rate and recognition rate. A new decision function quality criterion is defined to select good trade-off between recognition rate and processing time of pixel decision function. The first results of this study show that fast and efficient pixel classification with SVM is possible. Moreover posterior class pixel probability estimation is easy to compute with Platt method. Then a new segmentation scheme using probabilistic pixel classification has been developed. This one has several free parameters and an automatic selection must dealt with, but criteria for evaluate segmentation quality are not well adapted for cell segmentation, especially when comparison with expert pixel segmentation must be achieved. Another important contribution in this paper is the definition of a new quality criterion for evaluation of cell segmentation. The results presented here show that the selection of free parameters of the segmentation scheme by optimisation of the new quality cell segmentation criterion produces efficient cell segmentation.

  18. A generic efficient adaptive grid scheme for rocket propulsion modeling

    NASA Technical Reports Server (NTRS)

    Mo, J. D.; Chow, Alan S.

    1993-01-01

    The objective of this research is to develop an efficient, time-accurate numerical algorithm to discretize the Navier-Stokes equations for the predictions of internal one-, two-dimensional and axisymmetric flows. A generic, efficient, elliptic adaptive grid generator is implicitly coupled with the Lower-Upper factorization scheme in the development of ALUNS computer code. The calculations of one-dimensional shock tube wave propagation and two-dimensional shock wave capture, wave-wave interactions, shock wave-boundary interactions show that the developed scheme is stable, accurate and extremely robust. The adaptive grid generator produced a very favorable grid network by a grid speed technique. This generic adaptive grid generator is also applied in the PARC and FDNS codes and the computational results for solid rocket nozzle flowfield and crystal growth modeling by those codes will be presented in the conference, too. This research work is being supported by NASA/MSFC.

  19. Energy Efficient Cluster Based Scheduling Scheme for Wireless Sensor Networks.

    PubMed

    Janani, E Srie Vidhya; Kumar, P Ganesh

    2015-01-01

    The energy utilization of sensor nodes in large scale wireless sensor network points out the crucial need for scalable and energy efficient clustering protocols. Since sensor nodes usually operate on batteries, the maximum utility of network is greatly dependent on ideal usage of energy leftover in these sensor nodes. In this paper, we propose an Energy Efficient Cluster Based Scheduling Scheme for wireless sensor networks that balances the sensor network lifetime and energy efficiency. In the first phase of our proposed scheme, cluster topology is discovered and cluster head is chosen based on remaining energy level. The cluster head monitors the network energy threshold value to identify the energy drain rate of all its cluster members. In the second phase, scheduling algorithm is presented to allocate time slots to cluster member data packets. Here congestion occurrence is totally avoided. In the third phase, energy consumption model is proposed to maintain maximum residual energy level across the network. Moreover, we also propose a new packet format which is given to all cluster member nodes. The simulation results prove that the proposed scheme greatly contributes to maximum network lifetime, high energy, reduced overhead, and maximum delivery ratio.

  20. A Complete Hierarchical Key Management Scheme for Heterogeneous Wireless Sensor Networks

    PubMed Central

    Zheng, Xinying

    2014-01-01

    Heterogeneous cluster-based wireless sensor networks (WSN) attracted increasing attention recently. Obviously, the clustering makes the entire networks hierarchical; thus, several kinds of keys are required for hierarchical network topology. However, most existing key management schemes for it place more emphasis on pairwise key management schemes or key predistribution schemes and neglect the property of hierarchy. In this paper, we propose a complete hierarchical key management scheme which only utilizes symmetric cryptographic algorithms and low cost operations for heterogeneous cluster-based WSN. Our scheme considers four kinds of keys, which are an individual key, a cluster key, a master key, and pairwise keys, for each sensor node. Finally, the analysis and experiments demonstrate that the proposed scheme is secure and efficient; thus, it is suitable for heterogeneous cluster-based WSN. PMID:24983001

  1. An Efficient Location Verification Scheme for Static Wireless Sensor Networks.

    PubMed

    Kim, In-Hwan; Kim, Bo-Sung; Song, JooSeok

    2017-01-24

    In wireless sensor networks (WSNs), the accuracy of location information is vital to support many interesting applications. Unfortunately, sensors have difficulty in estimating their location when malicious sensors attack the location estimation process. Even though secure localization schemes have been proposed to protect location estimation process from attacks, they are not enough to eliminate the wrong location estimations in some situations. The location verification can be the solution to the situations or be the second-line defense. The problem of most of the location verifications is the explicit involvement of many sensors in the verification process and requirements, such as special hardware, a dedicated verifier and the trusted third party, which causes more communication and computation overhead. In this paper, we propose an efficient location verification scheme for static WSN called mutually-shared region-based location verification (MSRLV), which reduces those overheads by utilizing the implicit involvement of sensors and eliminating several requirements. In order to achieve this, we use the mutually-shared region between location claimant and verifier for the location verification. The analysis shows that MSRLV reduces communication overhead by 77% and computation overhead by 92% on average, when compared with the other location verification schemes, in a single sensor verification. In addition, simulation results for the verification of the whole network show that MSRLV can detect the malicious sensors by over 90% when sensors in the network have five or more neighbors.

  2. An Efficient Location Verification Scheme for Static Wireless Sensor Networks

    PubMed Central

    Kim, In-hwan; Kim, Bo-sung; Song, JooSeok

    2017-01-01

    In wireless sensor networks (WSNs), the accuracy of location information is vital to support many interesting applications. Unfortunately, sensors have difficulty in estimating their location when malicious sensors attack the location estimation process. Even though secure localization schemes have been proposed to protect location estimation process from attacks, they are not enough to eliminate the wrong location estimations in some situations. The location verification can be the solution to the situations or be the second-line defense. The problem of most of the location verifications is the explicit involvement of many sensors in the verification process and requirements, such as special hardware, a dedicated verifier and the trusted third party, which causes more communication and computation overhead. In this paper, we propose an efficient location verification scheme for static WSN called mutually-shared region-based location verification (MSRLV), which reduces those overheads by utilizing the implicit involvement of sensors and eliminating several requirements. In order to achieve this, we use the mutually-shared region between location claimant and verifier for the location verification. The analysis shows that MSRLV reduces communication overhead by 77% and computation overhead by 92% on average, when compared with the other location verification schemes, in a single sensor verification. In addition, simulation results for the verification of the whole network show that MSRLV can detect the malicious sensors by over 90% when sensors in the network have five or more neighbors. PMID:28125007

  3. A bandwidth efficient coding scheme for the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Pietrobon, Steven S.; Costello, Daniel J., Jr.

    1991-01-01

    As a demonstration of the performance capabilities of trellis codes using multidimensional signal sets, a Viterbi decoder was designed. The choice of code was based on two factors. The first factor was its application as a possible replacement for the coding scheme currently used on the Hubble Space Telescope (HST). The HST at present uses the rate 1/3 nu = 6 (with 2 (exp nu) = 64 states) convolutional code with Binary Phase Shift Keying (BPSK) modulation. With the modulator restricted to a 3 Msym/s, this implies a data rate of only 1 Mbit/s, since the bandwidth efficiency K = 1/3 bit/sym. This is a very bandwidth inefficient scheme, although the system has the advantage of simplicity and large coding gain. The basic requirement from NASA was for a scheme that has as large a K as possible. Since a satellite channel was being used, 8PSK modulation was selected. This allows a K of between 2 and 3 bit/sym. The next influencing factor was INTELSAT's intention of transmitting the SONET 155.52 Mbit/s standard data rate over the 72 MHz transponders on its satellites. This requires a bandwidth efficiency of around 2.5 bit/sym. A Reed-Solomon block code is used as an outer code to give very low bit error rates (BER). A 16 state rate 5/6, 2.5 bit/sym, 4D-8PSK trellis code was selected. This code has reasonable complexity and has a coding gain of 4.8 dB compared to uncoded 8PSK (2). This trellis code also has the advantage that it is 45 deg rotationally invariant. This means that the decoder needs only to synchronize to one of the two naturally mapped 8PSK signals in the signal set.

  4. A Query Result Merging Scheme for Providing Energy Efficiency in Underwater Sensor Networks

    PubMed Central

    Kim, Yunsung; Park, Soo-Hyun

    2011-01-01

    Underwater sensor networks are emerging as a promising distributed data management system for various applications in underwater environments, despite their limited accessibility and restricted energy capacity. With the aid of recent developments in ubiquitous data computing, an increasing number of users are expected to overcome low accessibility by applying queries to underwater sensor networks. However, when multiple users send queries to an underwater sensor network in a disorganized manner, it may incur lethal energy waste and problematic network traffic. The current query management mechanisms cannot effectively deal with this matter due to their limited applicability and unrealistic assumptions. In this paper, a novel query management scheme involving query result merging is proposed for underwater sensor networks. The mechanism is based on a relational database model and is adjusted to the practical restrictions affecting underwater communication environments. Network simulations will prove that the scheme becomes more efficient with a greater number of queries and a smaller period range. PMID:22247695

  5. Distributed Mobility Management Scheme for Mobile IPv6

    NASA Astrophysics Data System (ADS)

    Wakikawa, Ryuji; Valadon, Guillaume; Shigechika, Noriyuki; Murai, Jun

    Mobile IPv6 and Network Mobility (NEMO) have been standardized as IP extensions. While these technologies are planned to be adopted by several communities, such as the vehicle, aviation, and cellular industries, Mobile IPv6 has serious deployment issues such as scalability, protocol resilience, and redundancy. In these technologies, a special router called a home agent is introduced to support the movement of mobile nodes. This home agent introduces overlapping, inefficient routes, and becomes a single point of failure and a performance bottleneck. In this paper, a new concept for scalable and dependable mobility management scheme is proposed. Multiple home agents serve the same set of mobile nodes. The Home Agent Reliability protocol and Home Agent migration are introduced to achieve this concept. We also propose an overlay network named a Global Mobile eXchange (GMX) that efficiently handles data traffic from and to mobile nodes, and operates home agents as would an Internet eXchange Point (IXP).

  6. A Distributed Network Mobility Management Scheme for Hierarchical Mobile IPv6 Networks

    NASA Astrophysics Data System (ADS)

    Kawano, Keita; Kinoshita, Kazuhiko; Yamai, Nariyoshi

    Route optimization for network mobility is a key technique for providing a node in a mobile network (Mobile Network Node or MNN) with high quality broadband communications. Many schemes adding route optimization function to Network Mobility (NEMO) Basic Support protocol, the standardized network mobility management protocol from the IETF nemo working group, have already been proposed in recent years. One such scheme, a scheme using Hierarchical Mobile IPv6 (HMIPv6) aims to overcome micromobility management issues as well by applying a mechanism based on HMIPv6. The traditional scheme, however, suffers from a significant number of signaling messages as the number of MNNs and/or the number of their Correspondent Nodes (CNs) increase, because many messages notifying the MNNs' Home Agents (HAMNNs) and the CNs of the mobile network's movement are generated simultaneously each time the mobile network moves to the domain of another micromobility management router (Mobility Anchor Point or MAP). This paper proposes a scheme to overcome this problem. Our scheme reduces the number of signaling messages generated at the same time by managing the mobility of MNNs using multiple MAPs distributed within a network for load sharing. The results of simulation experiments show that our scheme works efficiently compared to the traditional scheme when a mobile network has many MNNs and/or these MNNs communicate with many CNs.

  7. A generalized well management scheme for reservoir simulation

    SciTech Connect

    Fang, W.Y.; Lo, K.K.

    1995-12-31

    A new generalized well management scheme has been formulated to maximize oil production under multiple facility constraints. The scheme integrates reserve performance, wellbore hydraulics, surface facility constraints and lift-gas allocation o maximize oil production. It predicts well performance based on up-to-date hydraulics and reservoir conditions. The scheme has been implemented in a black oil simulator by using Separable programming and Simplex algorithm. This production optimization scheme has been applied to two full-field models. The oil production of these two full-field models is limited by water, gas and liquid haling limits at both field- and flow station-levels. The gas production is limited by injectivity as well as gas handling limits. For a 12-year production forecast on Field A, the new scheme increased oil production by 3 to 9%. For a 12-year production forecast on field B, the new scheme increased oil production by 7 to 9%.

  8. A Watermarking Scheme for High Efficiency Video Coding (HEVC)

    PubMed Central

    Swati, Salahuddin; Hayat, Khizar; Shahid, Zafar

    2014-01-01

    This paper presents a high payload watermarking scheme for High Efficiency Video Coding (HEVC). HEVC is an emerging video compression standard that provides better compression performance as compared to its predecessor, i.e. H.264/AVC. Considering that HEVC may will be used in a variety of applications in the future, the proposed algorithm has a high potential of utilization in applications involving broadcast and hiding of metadata. The watermark is embedded into the Quantized Transform Coefficients (QTCs) during the encoding process. Later, during the decoding process, the embedded message can be detected and extracted completely. The experimental results show that the proposed algorithm does not significantly affect the video quality, nor does it escalate the bitrate. PMID:25144455

  9. Efficient hop by hop buffer class flow control schemes

    NASA Astrophysics Data System (ADS)

    Chen, Moo-Song; Kadaba, Bharath; Grover, George

    Design issues of hop-by-hop buffer class flow-control schemes are discussed. They are: (1) good window size for high-speed and large-propagation-delay environments and (2) the concept of congestion and access fairness. Schemes are proposed for buffer classification and window-size adjustment. A novel buffer classification, the path-based scheme, has the same fairness property but fewer classes than the route-based scheme. The window adjustment shceme, the quasistatic scheme, has similar or slightly worse performance to, but requires much less complexity than, dynamic schemes.

  10. Efficient stop-and-wait type II hybrid ARQ scheme

    NASA Astrophysics Data System (ADS)

    Kallel, S.

    1992-06-01

    The stop-and-wait (SW) Sastry's (1975) ARQ scheme is modified to include a parity retransmission type II hybrid ARQ scheme described by Lin and Yu (1982) and Kallel (1990). In the new scheme, the data packet to be transmitted is encoded with a rate of 1/2 code, and repetitions alternate between the two sequences obtained at the output of the encoder (unlike in the Sastry scheme in which simple repeats of a data packet are transmitted). It is shown that the use of the SW type II hybrid ARQ scheme results in a substantial increase of the throughput.

  11. Adaptive mobility management scheme in hierarchical mobile IPv6

    NASA Astrophysics Data System (ADS)

    Fang, Bo; Song, Junde

    2004-04-01

    Hierarchical mobile IPv6 makes the mobility management localized. Registration with HA is only needed while MN moving between MAP domains. This paper proposed an adaptive mobility management scheme based on the hierarchical mobile IPv6. The scheme focuses on the MN operation as well as MAP operation during the handoff. Adaptive MAP selection algorithm can be used to select a suitable MAP to register with once MN moves into a new subnet while MAP can thus adaptively changing his management domain. Furthermore, MAP can also adaptively changes its level in the hierarchical referring on the service load or other related information. Detailed handoff algorithm is also discussed in this paper.

  12. Efficient and Anonymous Authentication Scheme for Wireless Body Area Networks.

    PubMed

    Wu, Libing; Zhang, Yubo; Li, Li; Shen, Jian

    2016-06-01

    As a significant part of the Internet of Things (IoT), Wireless Body Area Network (WBAN) has attract much attention in this years. In WBANs, sensors placed in or around the human body collect the sensitive data of the body and transmit it through an open wireless channel in which the messages may be intercepted, modified, etc. Recently, Wang et al. presented a new anonymous authentication scheme for WBANs and claimed that their scheme can solve the security problems in the previous schemes. Unfortunately, we demonstrate that their scheme cannot withstand impersonation attack. Either an adversary or a malicious legal client could impersonate another legal client to the application provider. In this paper, we give the detailed weakness analysis of Wang et al.'s scheme at first. Then we present a novel anonymous authentication scheme for WBANs and prove that it's secure under a random oracle model. At last, we demonstrate that our presented anonymous authentication scheme for WBANs is more suitable for practical application than Wang et al.'s scheme due to better security and performance. Compared with Wang et al.'s scheme, the computation cost of our scheme in WBANs has reduced by about 31.58%.

  13. RD-optimized competition scheme for efficient motion prediction

    NASA Astrophysics Data System (ADS)

    Jung, J.; Laroche, G.; Pesquet, B.

    2007-01-01

    H.264/MPEG4-AVC is the latest video codec provided by the Joint Video Team, gathering ITU-T and ISO/IEC experts. Technically there are no drastic changes compared to its predecessors H.263 and MPEG-4 part 2. It however significantly reduces the bitrate and seems to be progressively adopted by the market. The gain mainly results from the addition of efficient motion compensation tools, variable block sizes, multiple reference frames, 1/4-pel motion accuracy and powerful Skip and Direct modes. A close study of the bits repartition in the bitstream reveals that motion information can represent up to 40% of the total bitstream. As a consequence reduction of motion cost is a priority for future enhancements. This paper proposes a competition-based scheme for the prediction of the motion. It impacts the selection of the motion vectors, based on a modified rate-distortion criterion, for the Inter modes and for the Skip mode. Combined spatial and temporal predictors take benefit of temporal redundancies, where the spatial median usually fails. An average 7% bitrate saving compared to a standard H.264/MPEG4-AVC codec is reported. In addition, on the fly adaptation of the set of predictors is proposed and preliminary results are provided.

  14. A simple, reliable and efficient scheme for automatic numerical integration

    NASA Astrophysics Data System (ADS)

    Pérez-Jordá, JoséM.; San-Fabián, Emilio; Moscardó, Federico

    1992-06-01

    A scheme for automatic numerical integration is presented. It uses the change of variable x=1+( {2}/{π}){[1+ {2}/{3}(1-z 2)]z√1-z 2 - arccosz} to transform the integral to be computed, ∫ 1-1f( x) d x, into ( {16}/{3π})∫ 1-1f(x)(1-z 2)√1-z 2dz , which is approximated by successive n-points Gauss-Chebyshev quadrature formulas of the second kind ( In). Due to the special nature of their abscissas and weights, a sequence of formulas I 1, I 3, I 7,…, I {(n-1)}/{2}, I n, I 2n+1 may be generated, such that I2 n+1 may be computed with only n + 1 new integrand evaluations, using the previous value of In. An error estimation is proposed for I2 n+1 , which only needs two previous values of the sequence ( In and I {(n+1)}/{2}). The algorithm may be implemented by a very short program (a FORTRAN 77 version is included) that spends practically all its running time in integrand evaluations. It is compared with other methods for automatic numerical integration (trapezoidal rule, Simpson's rule, Romberg's method, an adaptive Gauss-Kronrod rule and Clenshaw-Curtis method) over a broad set of 20 functions. We conclude that the present method is very simple and reliable and is the most efficient among the methods tested here. Possible applications in density functional theory are explored.

  15. EGPS: An Efficient Privacy Preserving Scheme for Vehicular ad hoc Networks

    NASA Astrophysics Data System (ADS)

    Zhao, Baokang; Su, Xiangyu; Su, Jinshu; Song, Ziming; Sun, Yipin; Tao, Jing; Tang, Yong; Chen, Shuhui; Zhao, Guohong; Chen, Yijiao

    2010-09-01

    In this paper, we propose EGPS, an efficient privacy preserving scheme for vehicular ad hoc networks. The EGPS scheme is based on a very efficient group signature and Identity Based Cryptography(IBC) techniques. Several security properties of EGPS, including the correctness and unforgeability have been proved. Furthermore, EGPS is also proved to be more efficient than GSIS, which is currently one of the best state-of-the-art VANET privacy preserving schemes.

  16. Efficient Non-interactive Universally Composable String-Commitment Schemes

    NASA Astrophysics Data System (ADS)

    Nishimaki, Ryo; Fujisaki, Eiichiro; Tanaka, Keisuke

    The universal composability (UC) for commitment is a very strong security notion. It guarantees that commitment schemes remain secure even if they are composed with arbitrary protocols and polynomially many copies of the schemes are run concurrently. Several UC commitment schemes in the common reference string (CRS) model have been proposed, but, they are either interactive commitment or bit-commitment (not string-commitment) schemes. We propose new non-interactive string-commitment schemes that achieve UC security in the CRS model assuming the difficulty of the decisional Diffie-Hellman problem or the decisional composite residuosity problem, but our schemes are not reusable. The main building blocks of our constructions are all-but-one trapdoor functions (ABO-TDFs) introduced by Peikert and Waters in STOC 2008 to construct secure public-key encryption schemes. Our main idea is to use the homomorphic properties of the function indices of the all-but-one trapdoor functions and to extend the functions to probabilistic ones by using re-randomization of ciphertexts. This is a new application of ABO-TDFs.

  17. An efficient quantum scheme for Private Set Intersection

    NASA Astrophysics Data System (ADS)

    Shi, Run-hua; Mu, Yi; Zhong, Hong; Cui, Jie; Zhang, Shun

    2016-01-01

    Private Set Intersection allows a client to privately compute set intersection with the collaboration of the server, which is one of the most fundamental and key problems within the multiparty collaborative computation of protecting the privacy of the parties. In this paper, we first present a cheat-sensitive quantum scheme for Private Set Intersection. Compared with classical schemes, our scheme has lower communication complexity, which is independent of the size of the server's set. Therefore, it is very suitable for big data services in Cloud or large-scale client-server networks.

  18. Performance evaluation of some ARQ schemes using efficient modulation techniques and noncoherent detection

    NASA Astrophysics Data System (ADS)

    Fantacci, Romano

    1991-03-01

    The performance of generalized automatic repeat request (ARQ) schemes with continuous-phase frequency-shift-keying (CPFSK) modulation schemes and noncoherent detection is analyzed. In the proposed schemes, each bit of a block is transmitted m times consecutively to increase the transmission reliability. Efficient CPFSK schemes are considered because they represent a class of joint power- and bandwidth-efficient digital modulation schemes with constant amplitude, which can be coherently or noncoherently demodulated. The theoretically derived throughput is optimized for each bit's transmitted copies. In comparison with the classical ARQ schemes, the proposed schemes provide enhanced throughput, especially under high error rate conditions. The use of the noncoherent detection greatly reduces the receiver implementation complexity. The schemes can also be used when coherent detection is required.

  19. An effective and secure key-management scheme for hierarchical access control in E-medicine system.

    PubMed

    Odelu, Vanga; Das, Ashok Kumar; Goswami, Adrijit

    2013-04-01

    Recently several hierarchical access control schemes are proposed in the literature to provide security of e-medicine systems. However, most of them are either insecure against 'man-in-the-middle attack' or they require high storage and computational overheads. Wu and Chen proposed a key management method to solve dynamic access control problems in a user hierarchy based on hybrid cryptosystem. Though their scheme improves computational efficiency over Nikooghadam et al.'s approach, it suffers from large storage space for public parameters in public domain and computational inefficiency due to costly elliptic curve point multiplication. Recently, Nikooghadam and Zakerolhosseini showed that Wu-Chen's scheme is vulnerable to man-in-the-middle attack. In order to remedy this security weakness in Wu-Chen's scheme, they proposed a secure scheme which is again based on ECC (elliptic curve cryptography) and efficient one-way hash function. However, their scheme incurs huge computational cost for providing verification of public information in the public domain as their scheme uses ECC digital signature which is costly when compared to symmetric-key cryptosystem. In this paper, we propose an effective access control scheme in user hierarchy which is only based on symmetric-key cryptosystem and efficient one-way hash function. We show that our scheme reduces significantly the storage space for both public and private domains, and computational complexity when compared to Wu-Chen's scheme, Nikooghadam-Zakerolhosseini's scheme, and other related schemes. Through the informal and formal security analysis, we further show that our scheme is secure against different attacks and also man-in-the-middle attack. Moreover, dynamic access control problems in our scheme are also solved efficiently compared to other related schemes, making our scheme is much suitable for practical applications of e-medicine systems.

  20. Efficient Low Dissipative High Order Schemes for Multiscale MHD Flows

    NASA Technical Reports Server (NTRS)

    Sjoegreen, Bjoern; Yee, Helen C.; Mansour, Nagi (Technical Monitor)

    2002-01-01

    Accurate numerical simulations of complex multiscale compressible viscous flows, especially high speed turbulence combustion and acoustics, demand high order schemes with adaptive numerical dissipation controls. Standard high resolution shock-capturing methods are too dissipative to capture the small scales and/or long-time wave propagations without extreme grid refinements and small time steps. An integrated approach for the control of numerical dissipation in high order schemes for the compressible Euler and Navier-Stokes equations has been developed and verified by the authors and collaborators. These schemes are suitable for the problems in question. Basically, the scheme consists of sixth-order or higher non-dissipative spatial difference operators as the base scheme. To control the amount of numerical dissipation, multiresolution wavelets are used as sensors to adaptively limit the amount and to aid the selection and/or blending of the appropriate types of numerical dissipation to be used. Magnetohydrodynamics (MHD) waves play a key role in drag reduction in highly maneuverable high speed combat aircraft, in space weather forecasting, and in the understanding of the dynamics of the evolution of our solar system and the main sequence stars. Although there exist a few well-studied second and third-order high-resolution shock-capturing schemes for the MHD in the literature, these schemes are too diffusive and not practical for turbulence/combustion MHD flows. On the other hand, extension of higher than third-order high-resolution schemes to the MHD system of equations is not straightforward. Unlike the hydrodynamic equations, the inviscid MHD system is non-strictly hyperbolic with non-convex fluxes. The wave structures and shock types are different from their hydrodynamic counterparts. Many of the non-traditional hydrodynamic shocks are not fully understood. Consequently, reliable and highly accurate numerical schemes for multiscale MHD equations pose a great

  1. Efficient Low Dissipative High Order Schemes for Multiscale MHD Flows

    NASA Technical Reports Server (NTRS)

    Sjoegreen, Bjoern; Yee, Helen C.; Mansour, Nagi (Technical Monitor)

    2002-01-01

    Accurate numerical simulations of complex multiscale compressible viscous flows, especially high speed turbulence combustion and acoustics, demand high order schemes with adaptive numerical dissipation controls. Standard high resolution shock-capturing methods are too dissipative to capture the small scales and/or long-time wave propagations without extreme grid refinements and small time steps. An integrated approach for the control of numerical dissipation in high order schemes for the compressible Euler and Navier-Stokes equations has been developed and verified by the authors and collaborators. These schemes are suitable for the problems in question. Basically, the scheme consists of sixth-order or higher non-dissipative spatial difference operators as the base scheme. To control the amount of numerical dissipation, multiresolution wavelets are used as sensors to adaptively limit the amount and to aid the selection and/or blending of the appropriate types of numerical dissipation to be used. Magnetohydrodynamics (MHD) waves play a key role in drag reduction in highly maneuverable high speed combat aircraft, in space weather forecasting, and in the understanding of the dynamics of the evolution of our solar system and the main sequence stars. Although there exist a few well-studied second and third-order high-resolution shock-capturing schemes for the MHD in the literature, these schemes are too diffusive and not practical for turbulence/combustion MHD flows. On the other hand, extension of higher than third-order high-resolution schemes to the MHD system of equations is not straightforward. Unlike the hydrodynamic equations, the inviscid MHD system is non-strictly hyperbolic with non-convex fluxes. The wave structures and shock types are different from their hydrodynamic counterparts. Many of the non-traditional hydrodynamic shocks are not fully understood. Consequently, reliable and highly accurate numerical schemes for multiscale MHD equations pose a great

  2. Resource Management Scheme Based on Ubiquitous Data Analysis

    PubMed Central

    Lee, Heung Ki; Jung, Jaehee

    2014-01-01

    Resource management of the main memory and process handler is critical to enhancing the system performance of a web server. Owing to the transaction delay time that affects incoming requests from web clients, web server systems utilize several web processes to anticipate future requests. This procedure is able to decrease the web generation time because there are enough processes to handle the incoming requests from web browsers. However, inefficient process management results in low service quality for the web server system. Proper pregenerated process mechanisms are required for dealing with the clients' requests. Unfortunately, it is difficult to predict how many requests a web server system is going to receive. If a web server system builds too many web processes, it wastes a considerable amount of memory space, and thus performance is reduced. We propose an adaptive web process manager scheme based on the analysis of web log mining. In the proposed scheme, the number of web processes is controlled through prediction of incoming requests, and accordingly, the web process management scheme consumes the least possible web transaction resources. In experiments, real web trace data were used to prove the improved performance of the proposed scheme. PMID:25197692

  3. An Efficient Hierarchical Video Coding Scheme Combining Visual Perception Characteristics

    PubMed Central

    Liu, Pengyu; Jia, Kebin

    2014-01-01

    Different visual perception characteristic saliencies are the key to constitute the low-complexity video coding framework. A hierarchical video coding scheme based on human visual systems (HVS) is proposed in this paper. The proposed scheme uses a joint video coding framework consisting of visual perception analysis layer (VPAL) and video coding layer (VCL). In VPAL, effective visual perception characteristics detection algorithm is proposed to achieve visual region of interest (VROI) based on the correlation between coding information (such as motion vector, prediction mode, etc.) and visual attention. Then, the interest priority setting for VROI according to visual perception characteristics is completed. In VCL, the optional encoding method is developed utilizing the visual interested priority setting results from VPAL. As a result, the proposed scheme achieves information reuse and complementary between visual perception analysis and video coding. Experimental results show that the proposed hierarchical video coding scheme effectively alleviates the contradiction between complexity and accuracy. Compared with H.264/AVC (JM17.0), the proposed scheme reduces 80% video coding time approximately and maintains a good video image quality as well. It improves video coding performance significantly. PMID:24959623

  4. Efficient Scheme for Perfect Collective Einstein-Podolsky-Rosen Steering

    PubMed Central

    Wang, M.; Gong, Q. H.; Ficek, Z.; He, Q. Y.

    2015-01-01

    A practical scheme for the demonstration of perfect one-sided device-independent quantum secret sharing is proposed. The scheme involves a three-mode optomechanical system in which a pair of independent cavity modes is driven by short laser pulses and interact with a movable mirror. We demonstrate that by tuning the laser frequency to the blue (anti-Stokes) sideband of the average frequency of the cavity modes, the modes become mutually coherent and then may collectively steer the mirror mode to a perfect Einstein-Podolsky-Rosen state. The scheme is shown to be experimentally feasible, it is robust against the frequency difference between the modes, mechanical thermal noise and damping, and coupling strengths of the cavity modes to the mirror. PMID:26212901

  5. Efficient Scheme for Perfect Collective Einstein-Podolsky-Rosen Steering.

    PubMed

    Wang, M; Gong, Q H; Ficek, Z; He, Q Y

    2015-07-27

    A practical scheme for the demonstration of perfect one-sided device-independent quantum secret sharing is proposed. The scheme involves a three-mode optomechanical system in which a pair of independent cavity modes is driven by short laser pulses and interact with a movable mirror. We demonstrate that by tuning the laser frequency to the blue (anti-Stokes) sideband of the average frequency of the cavity modes, the modes become mutually coherent and then may collectively steer the mirror mode to a perfect Einstein-Podolsky-Rosen state. The scheme is shown to be experimentally feasible, it is robust against the frequency difference between the modes, mechanical thermal noise and damping, and coupling strengths of the cavity modes to the mirror.

  6. Efficient Scheme for Perfect Collective Einstein-Podolsky-Rosen Steering

    NASA Astrophysics Data System (ADS)

    Wang, M.; Gong, Q. H.; Ficek, Z.; He, Q. Y.

    2015-07-01

    A practical scheme for the demonstration of perfect one-sided device-independent quantum secret sharing is proposed. The scheme involves a three-mode optomechanical system in which a pair of independent cavity modes is driven by short laser pulses and interact with a movable mirror. We demonstrate that by tuning the laser frequency to the blue (anti-Stokes) sideband of the average frequency of the cavity modes, the modes become mutually coherent and then may collectively steer the mirror mode to a perfect Einstein-Podolsky-Rosen state. The scheme is shown to be experimentally feasible, it is robust against the frequency difference between the modes, mechanical thermal noise and damping, and coupling strengths of the cavity modes to the mirror.

  7. Efficient Buffering Scheme in the LMA for Seamless Handover in PMIPv6

    NASA Astrophysics Data System (ADS)

    Kim, Kwang-Ryoul; Lee, Hyo-Beom; Choi, Hyon-Young; Min, Sung-Gi; Han, Youn-Hee

    Proxy Mobile IPv6 (PMIPv6) is proposed as a new network-based local mobility protocol which does not involve the Mobile Node (MN) in mobility management. PMIPv6, which uses link-layer attachment information, reduces the movement detection time and eliminates duplicate address detection procedures in order to provide faster handover than Mobile IPv6 (MIPv6). To eliminate packet loss during the handover period, the Local Mobility Anchor (LMA) buffering scheme is proposed. In this scheme, the LMA buffers lost packets of the Mobile Access Gateway (MAG) and the MN during the handover and recovers them after handover. A new Automatic Repeat reQuest (ARQ) handler is defined which efficiently manages the LMA buffer. The ARQ handler relays ARQ result between the MAG and the MN to the LMA. The LMA removes any buffered packets which have been successfully delivered to the MN. The ARQ handler recovers the packet loss during the handover using buffered packets in the LMA. The ARQ information, between the MAG and LMA, is inserted in the outer header of IP-in-IP encapsulated packets of a standard PMIPv6 tunnel. Since the proposed scheme simply adds information to the standard operation of an IP-in-IP tunnel between the LMA and the MAG, it can be implemented seamlessly without modification to the original PMIPv6 messages and signaling sequence. Unlike other Fast Handovers for Mobile IPv6 (FMIPv6) based enhancement for PMIPv6, the proposed scheme does not require any handover related information before the actual handover.

  8. Efficient implementation of essentially non-oscillatory shock capturing schemes

    NASA Technical Reports Server (NTRS)

    Shu, Chi-Wang; Osher, Stanley

    1987-01-01

    In the computation of discontinuous solutions of hyperbolic conservation laws, TVD (total-variation-diminishing), TVB (total-variation-bounded) and the recently developed ENO (essentially non-oscillatory) schemes have proven to be very useful. In this paper two improvements are discussed: a simple TVD Runge-Kutta type time discretization, and an ENO construction procedure based on fluxes rather than on cell averages. These improvements simplify the schemes considerably -- especially for multi-dimensional problems or problems with forcing terms. Preliminary numerical results are also given.

  9. Key Management Scheme Based on Route Planning of Mobile Sink in Wireless Sensor Networks.

    PubMed

    Zhang, Ying; Liang, Jixing; Zheng, Bingxin; Jiang, Shengming; Chen, Wei

    2016-01-29

    In many wireless sensor network application scenarios the key management scheme with a Mobile Sink (MS) should be fully investigated. This paper proposes a key management scheme based on dynamic clustering and optimal-routing choice of MS. The concept of Traveling Salesman Problem with Neighbor areas (TSPN) in dynamic clustering for data exchange is proposed, and the selection probability is used in MS route planning. The proposed scheme extends static key management to dynamic key management by considering the dynamic clustering and mobility of MSs, which can effectively balance the total energy consumption during the activities. Considering the different resources available to the member nodes and sink node, the session key between cluster head and MS is established by modified an ECC encryption with Diffie-Hellman key exchange (ECDH) algorithm and the session key between member node and cluster head is built with a binary symmetric polynomial. By analyzing the security of data storage, data transfer and the mechanism of dynamic key management, the proposed scheme has more advantages to help improve the resilience of the key management system of the network on the premise of satisfying higher connectivity and storage efficiency.

  10. Key Management Scheme Based on Route Planning of Mobile Sink in Wireless Sensor Networks

    PubMed Central

    Zhang, Ying; Liang, Jixing; Zheng, Bingxin; Jiang, Shengming; Chen, Wei

    2016-01-01

    In many wireless sensor network application scenarios the key management scheme with a Mobile Sink (MS) should be fully investigated. This paper proposes a key management scheme based on dynamic clustering and optimal-routing choice of MS. The concept of Traveling Salesman Problem with Neighbor areas (TSPN) in dynamic clustering for data exchange is proposed, and the selection probability is used in MS route planning. The proposed scheme extends static key management to dynamic key management by considering the dynamic clustering and mobility of MSs, which can effectively balance the total energy consumption during the activities. Considering the different resources available to the member nodes and sink node, the session key between cluster head and MS is established by modified an ECC encryption with Diffie-Hellman key exchange (ECDH) algorithm and the session key between member node and cluster head is built with a binary symmetric polynomial. By analyzing the security of data storage, data transfer and the mechanism of dynamic key management, the proposed scheme has more advantages to help improve the resilience of the key management system of the network on the premise of satisfying higher connectivity and storage efficiency. PMID:26840311

  11. An Efficient Signature Matching Scheme for Mobile Security

    NASA Astrophysics Data System (ADS)

    Zhang, Ruhui; Iwata, Makoto

    The development of network technology reveals the clear trend that mobile devices will soon be equipped with more and more network-based functions and services. This increase also results in more intrusions and attacks on mobile devices; therefore, mobile security mechanisms are becoming indispensable. In this paper, we propose a novel signature matching scheme for mobile security. This scheme not only emphasizes a small resource requirement and an optimal scan speed, which are both important for resource-limited mobile devices, but also focuses on practical features such as stable performance, fast signature set updates and hardware implementation. This scheme is based on the finite state machine (FSM) approach widely used for string matching. An SRAM-based two-level finite state machine (TFSM) solution is introduced to utilize the unbalanced transition distribution in the original FSM to decrease the memory requirement, and to shorten the critical path of the single-FSM solution. By adjusting the boundary of the two FSMs, optimum memory usage and throughput are obtainable. The hardware circuit of our scheme is designed and evaluated by both FPGA and ASIC technology. The result of FPGA evaluation shows that 2,168 unique patterns with a total of 32,776 characters are stored in 177.75KB SelectRAM blocks of Xilinx XC4VLX40 FPGA and a 3.0Gbps throughput is achieved. The result of ASIC evaluation with 180nm-CMOS library shows a throughput of over 4.5Gbps with 132KB of SRAM. Because of the small amount of memory and logic cell requirements, as well as the scalability of our scheme, higher performance is achieved by instantiating several signature matching engines when more resources are provided.

  12. An Efficient Scheduling Scheme on Charging Stations for Smart Transportation

    NASA Astrophysics Data System (ADS)

    Kim, Hye-Jin; Lee, Junghoon; Park, Gyung-Leen; Kang, Min-Jae; Kang, Mikyung

    This paper proposes a reservation-based scheduling scheme for the charging station to decide the service order of multiple requests, aiming at improving the satisfiability of electric vehicles. The proposed scheme makes it possible for a customer to reduce the charge cost and waiting time, while a station can extend the number of clients it can serve. A linear rank function is defined based on estimated arrival time, waiting time bound, and the amount of needed power, reducing the scheduling complexity. Receiving the requests from the clients, the power station decides the charge order by the rank function and then replies to the requesters with the waiting time and cost it can guarantee. Each requester can decide whether to charge at that station or try another station. This scheduler can evolve to integrate a new pricing policy and services, enriching the electric vehicle transport system.

  13. An Energy Efficient Cooperative Hierarchical MIMO Clustering Scheme for Wireless Sensor Networks

    PubMed Central

    Nasim, Mehwish; Qaisar, Saad; Lee, Sungyoung

    2012-01-01

    In this work, we present an energy efficient hierarchical cooperative clustering scheme for wireless sensor networks. Communication cost is a crucial factor in depleting the energy of sensor nodes. In the proposed scheme, nodes cooperate to form clusters at each level of network hierarchy ensuring maximal coverage and minimal energy expenditure with relatively uniform distribution of load within the network. Performance is enhanced by cooperative multiple-input multiple-output (MIMO) communication ensuring energy efficiency for WSN deployments over large geographical areas. We test our scheme using TOSSIM and compare the proposed scheme with cooperative multiple-input multiple-output (CMIMO) clustering scheme and traditional multihop Single-Input-Single-Output (SISO) routing approach. Performance is evaluated on the basis of number of clusters, number of hops, energy consumption and network lifetime. Experimental results show significant energy conservation and increase in network lifetime as compared to existing schemes. PMID:22368459

  14. An energy efficient cooperative hierarchical MIMO clustering scheme for wireless sensor networks.

    PubMed

    Nasim, Mehwish; Qaisar, Saad; Lee, Sungyoung

    2012-01-01

    In this work, we present an energy efficient hierarchical cooperative clustering scheme for wireless sensor networks. Communication cost is a crucial factor in depleting the energy of sensor nodes. In the proposed scheme, nodes cooperate to form clusters at each level of network hierarchy ensuring maximal coverage and minimal energy expenditure with relatively uniform distribution of load within the network. Performance is enhanced by cooperative multiple-input multiple-output (MIMO) communication ensuring energy efficiency for WSN deployments over large geographical areas. We test our scheme using TOSSIM and compare the proposed scheme with cooperative multiple-input multiple-output (CMIMO) clustering scheme and traditional multihop Single-Input-Single-Output (SISO) routing approach. Performance is evaluated on the basis of number of clusters, number of hops, energy consumption and network lifetime. Experimental results show significant energy conservation and increase in network lifetime as compared to existing schemes.

  15. On large time step TVD scheme for hyperbolic conservation laws and its efficiency evaluation

    NASA Astrophysics Data System (ADS)

    Qian, ZhanSen; Lee, Chun-Hian

    2012-08-01

    A large time step (LTS) TVD scheme originally proposed by Harten is modified and further developed in the present paper and applied to Euler equations in multidimensional problems. By firstly revealing the drawbacks of Harten's original LTS TVD scheme, and reasoning the occurrence of the spurious oscillations, a modified formulation of its characteristic transformation is proposed and a high resolution, strongly robust LTS TVD scheme is formulated. The modified scheme is proven to be capable of taking larger number of time steps than the original one. Following the modified strategy, the LTS TVD schemes for Yee's upwind TVD scheme and Yee-Roe-Davis's symmetric TVD scheme are constructed. The family of the LTS schemes is then extended to multidimensional by time splitting procedure, and the associated boundary condition treatment suitable for the LTS scheme is also imposed. The numerical experiments on Sod's shock tube problem, inviscid flows over NACA0012 airfoil and ONERA M6 wing are performed to validate the developed schemes. Computational efficiencies for the respective schemes under different CFL numbers are also evaluated and compared. The results reveal that the improvement is sizable as compared to the respective single time step schemes, especially for the CFL number ranging from 1.0 to 4.0.

  16. An Efficient and Provable Secure Revocable Identity-Based Encryption Scheme

    PubMed Central

    Wang, Changji; Li, Yuan; Xia, Xiaonan; Zheng, Kangjia

    2014-01-01

    Revocation functionality is necessary and crucial to identity-based cryptosystems. Revocable identity-based encryption (RIBE) has attracted a lot of attention in recent years, many RIBE schemes have been proposed in the literature but shown to be either insecure or inefficient. In this paper, we propose a new scalable RIBE scheme with decryption key exposure resilience by combining Lewko and Waters’ identity-based encryption scheme and complete subtree method, and prove our RIBE scheme to be semantically secure using dual system encryption methodology. Compared to existing scalable and semantically secure RIBE schemes, our proposed RIBE scheme is more efficient in term of ciphertext size, public parameters size and decryption cost at price of a little looser security reduction. To the best of our knowledge, this is the first construction of scalable and semantically secure RIBE scheme with constant size public system parameters. PMID:25238418

  17. An efficient and provable secure revocable identity-based encryption scheme.

    PubMed

    Wang, Changji; Li, Yuan; Xia, Xiaonan; Zheng, Kangjia

    2014-01-01

    Revocation functionality is necessary and crucial to identity-based cryptosystems. Revocable identity-based encryption (RIBE) has attracted a lot of attention in recent years, many RIBE schemes have been proposed in the literature but shown to be either insecure or inefficient. In this paper, we propose a new scalable RIBE scheme with decryption key exposure resilience by combining Lewko and Waters' identity-based encryption scheme and complete subtree method, and prove our RIBE scheme to be semantically secure using dual system encryption methodology. Compared to existing scalable and semantically secure RIBE schemes, our proposed RIBE scheme is more efficient in term of ciphertext size, public parameters size and decryption cost at price of a little looser security reduction. To the best of our knowledge, this is the first construction of scalable and semantically secure RIBE scheme with constant size public system parameters.

  18. Efficient spin injector scheme based on Heusler materials.

    PubMed

    Chadov, Stanislav; Graf, Tanja; Chadova, Kristina; Dai, Xuefang; Casper, Frederick; Fecher, Gerhard H; Felser, Claudia

    2011-07-22

    We present a rational design scheme intended to provide stable high spin polarization at the interfaces of the magnetoresistive junctions by fulfilling the criteria of structural and chemical compatibilities at the interface. This can be realized by joining the semiconducting and half-metallic Heusler materials with similar structures. The present first-principles calculations verify that the interface remains half-metallic if the nearest interface layers effectively form a stable Heusler material with the properties intermediately between the surrounding bulk parts. This leads to a simple rule for selecting the proper combinations.

  19. From generic scheme to brand-generic scheme: Have new policy influenced the efficiency of Iranian pharmaceutical companies?

    PubMed

    Hashemi-Meshkini, Amir; Varmaghani, Mehdi; Yousefi, Mehdi; Yaghoubifard, Saeed; Zekri, Hedieh-Sadat; Nikfar, Shekoufeh; Kebriaeezadeh, Abbas

    2014-07-01

    Brand-generic scheme was implemented in Iran to improve the competition in the pharmaceutical market. In this study, we aim to assess if this policy had any positive effect on efficiency of Iranian pharmaceutical companies. We used data envelopment analysis to evaluate the relative efficiency of pharmaceutical companies during 1999-2008. The Wilcoxon matched-pairs signed-rank and sign tests were used to assess the difference between mean technical efficiency of companies before and after implementation of the new policy. Although the Wilcoxon matched-pairs signed-rank tests did not show any significant differences in favor of the new policy in terms of both relative and pure (managerial) technical efficiency for included companies (P = 0.079 and 0.07, respectively), but the one-sided sign test indicated that only relative pure (managerial) efficiency has been improved after this policy (P = 0.031). The "brand-generic scheme" does not seem to be a successful policy to improve efficiency level and prompt competition in pharmaceutical companies in Iran. To achieve this aim, consideration of infrastructural requirements including transparent and non-discriminating laws and regulations to support competition, the competitive pricing policies, the presence of international companies in the market, and full privatization of companies had to be also deeming by policy makers.

  20. More Efficient Threshold Signature Scheme in Gap Diffie-Hellman Group

    NASA Astrophysics Data System (ADS)

    Nyang, Daehun; Yamamura, Akihiro

    By modifying the private key and the public key setting in Boneh-Lynn-Shacham's short signature shcheme, a variation of BLS' short signature scheme is proposed. Based on this variation, we present a very efficient threshold signature scheme where the number of pairing computation for the signaure share verification reduces to half.

  1. High-Efficient Arbitrated Quantum Signature Scheme Based on Cluster States

    NASA Astrophysics Data System (ADS)

    Fatahi, Negin; Naseri, Mosayeb; Gong, Li-Hua; Liao, Qing-Hong

    2017-02-01

    The arbitrated quantum signature characteristics including the security and the efficiency are investigated and a new efficient and secure arbitrated quantum signature is proposed. It is shown that the proposed scheme exhibits an efficiency of 64 %. Furthermore, to gain a higher security, the decoy photons security checking is employed.

  2. Wireless Instrumentation System and Power Management Scheme Therefore

    NASA Technical Reports Server (NTRS)

    Perotti, Jose (Inventor); Lucena, Angel (Inventor); Eckhoff, Anthony (Inventor); Mata, Carlos T. (Inventor); Blalock, Norman N. (Inventor); Medelius, Pedro J. (Inventor)

    2007-01-01

    A wireless instrumentation system enables a plurality of low power wireless transceivers to transmit measurement data from a plurality of remote station sensors to a central data station accurately and reliably. The system employs a relay based communications scheme where remote stations that cannot communicate directly with the central station due to interference, poor signal strength, etc., are instructed to communicate with other of the remote stations that act as relays to the central station. A unique power management scheme is also employed to minimize power usage at each remote station and thereby maximize battery life. Each of the remote stations prefembly employs a modular design to facilitate easy reconfiguration of the stations as required.

  3. Communication Improvement for the LU NAS Parallel Benchmark: A Model for Efficient Parallel Relaxation Schemes

    NASA Technical Reports Server (NTRS)

    Yarrow, Maurice; VanderWijngaart, Rob; Kutler, Paul (Technical Monitor)

    1997-01-01

    The first release of the MPI version of the LU NAS Parallel Benchmark (NPB2.0) performed poorly compared to its companion NPB2.0 codes. The later LU release (NPB2.1 & 2.2) runs up to two and a half times faster, thanks to a revised point access scheme and related communications scheme. The new scheme sends substantially fewer messages. is cache "friendly", and has a better load balance. We detail the, observations and modifications that resulted in this efficiency improvement, and show that the poor behavior of the original code resulted from deriving a message passing scheme from an algorithm originally devised for a vector architecture.

  4. An efficient and secure attribute based signcryption scheme with LSSS access structure.

    PubMed

    Hong, Hanshu; Sun, Zhixin

    2016-01-01

    Attribute based encryption (ABE) and attribute based signature (ABS) provide flexible access control with authentication for data sharing between users, but realizing both functions will bring about too much computation burden. In this paper, we combine the advantages of CP-ABE with ABS and propose a ciphertext policy attribute based signcryption scheme. In our scheme, only legal receivers can decrypt the ciphertext and verify the signature signed by data owner. Furthermore, we use linear secret sharing scheme instead of tree structure to avoid the frequent calls of recursive algorithm. By security and performance analysis, we prove that our scheme is secure as well as gains higher efficiency.

  5. Power and spectrally efficient M-ARY QAM schemes for future mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Sreenath, K.; Feher, K.

    1990-01-01

    An effective method to compensate nonlinear phase distortion caused by the mobile amplifier is proposed. As a first step towards the future use of spectrally efficient modulation schemes for mobile satellite applications, we have investigated effects of nonlinearities and the phase compensation method on 16-QAM. The new method provides about 2 dB savings in power for 16-QAM operation with cost effective amplifiers near saturation and thereby promising use of spectrally efficient linear modulation schemes for future mobile satellite applications.

  6. Power and spectrally efficient M-ARY QAM schemes for future mobile satellite communications

    NASA Astrophysics Data System (ADS)

    Sreenath, K.; Feher, K.

    An effective method to compensate nonlinear phase distortion caused by the mobile amplifier is proposed. As a first step towards the future use of spectrally efficient modulation schemes for mobile satellite applications, we have investigated effects of nonlinearities and the phase compensation method on 16-QAM. The new method provides about 2 dB savings in power for 16-QAM operation with cost effective amplifiers near saturation and thereby promising use of spectrally efficient linear modulation schemes for future mobile satellite applications.

  7. Efficient spares matrix multiplication scheme for the CYBER 203

    NASA Technical Reports Server (NTRS)

    Lambiotte, J. J., Jr.

    1984-01-01

    This work has been directed toward the development of an efficient algorithm for performing this computation on the CYBER-203. The desire to provide software which gives the user the choice between the often conflicting goals of minimizing central processing (CPU) time or storage requirements has led to a diagonal-based algorithm in which one of three types of storage is selected for each diagonal. For each storage type, an initialization sub-routine estimates the CPU and storage requirements based upon results from previously performed numerical experimentation. These requirements are adjusted by weights provided by the user which reflect the relative importance the user places on the resources. The three storage types employed were chosen to be efficient on the CYBER-203 for diagonals which are sparse, moderately sparse, or dense; however, for many densities, no diagonal type is most efficient with respect to both resource requirements. The user-supplied weights dictate the choice.

  8. Efficient multiobjective optimization scheme for large scale structures

    NASA Astrophysics Data System (ADS)

    Grandhi, Ramana V.; Bharatram, Geetha; Venkayya, V. B.

    1992-09-01

    This paper presents a multiobjective optimization algorithm for an efficient design of large scale structures. The algorithm is based on generalized compound scaling techniques to reach the intersection of multiple functions. Multiple objective functions are treated similar to behavior constraints. Thus, any number of objectives can be handled in the formulation. Pseudo targets on objectives are generated at each iteration in computing the scale factors. The algorithm develops a partial Pareto set. This method is computationally efficient due to the fact that it does not solve many single objective optimization problems in reaching the Pareto set. The computational efficiency is compared with other multiobjective optimization methods, such as the weighting method and the global criterion method. Trusses, plate, and wing structure design cases with stress and frequency considerations are presented to demonstrate the effectiveness of the method.

  9. A genuinely multidimensional upwind scheme and efficient multigrid solver for the compressible Euler equations

    NASA Technical Reports Server (NTRS)

    Sidilkover, David

    1994-01-01

    We present a new approach towards the construction of a genuinely multidimensional high-resolution scheme for computing steady-state solutions of the Euler equations of gas dynamics. The unique advantage of this approach is that the Gauss-Seidel relaxation is stable when applied directly to the high-resolution discrete equations, thus allowing us to construct a very efficient and simple multigrid steady-state solver. This is the only high-resolution scheme known to us that has this property. The two-dimensional scheme is presented in detail. It is formulated on triangular (structured and unstructured) meshes and can be interpreted as a genuinely two-dimensional extension of the Roe scheme. The quality of the solutions obtained using this scheme and the performance of the multigrid algorithm are illustrated by the numerical experiments. Construction of the three dimensional scheme is outlined briefly as well.

  10. Extension of Efficient Low Dissipative High Order Schemes for 3-D Curvilinear Moving Grids

    NASA Technical Reports Server (NTRS)

    Vinokur, Marcel; Yee H. C.; Koga, Dennis (Technical Monitor)

    2000-01-01

    The efficient low dissipative high order schemes proposed by Yee et al. is formulated for 3-D curvilinear moving grids. These schemes consists of a high order base schemes combined with nonlinear characteristic filters. The amount of numerical dissipation is minimized by applying the schemes to the entropy splitting form of the inviscid flux derivatives. The analysis is given for a thermally perfect gas. The main difficulty in the extension of higher order schemes that were formulated in Cartesian coordinates to curvilinear moving grids is the higher order transformed metric evaluations. The higher order numerical evaluation of the transformed metric terms to insure freestream preservation is done in a coordinate invariant manner. The formulation is an improvement over existing formulation of high order scheme in curvilinear moving grids.

  11. Efficient sampling schemes for assessing soil tillage intensity

    USDA-ARS?s Scientific Manuscript database

    Crop residue or plant litter is the portion of a crop left in the field after harvest. Crop residues on the soil surface provide a protective barrier against water and wind erosion and reduce the amounts of soil, nutrients, and pesticides that reach streams and rivers. Management of crop residues i...

  12. A privacy preserving secure and efficient authentication scheme for telecare medical information systems.

    PubMed

    Mishra, Raghavendra; Barnwal, Amit Kumar

    2015-05-01

    The Telecare medical information system (TMIS) presents effective healthcare delivery services by employing information and communication technologies. The emerging privacy and security are always a matter of great concern in TMIS. Recently, Chen at al. presented a password based authentication schemes to address the privacy and security. Later on, it is proved insecure against various active and passive attacks. To erase the drawbacks of Chen et al.'s anonymous authentication scheme, several password based authentication schemes have been proposed using public key cryptosystem. However, most of them do not present pre-smart card authentication which leads to inefficient login and password change phases. To present an authentication scheme with pre-smart card authentication, we present an improved anonymous smart card based authentication scheme for TMIS. The proposed scheme protects user anonymity and satisfies all the desirable security attributes. Moreover, the proposed scheme presents efficient login and password change phases where incorrect input can be quickly detected and a user can freely change his password without server assistance. Moreover, we demonstrate the validity of the proposed scheme by utilizing the widely-accepted BAN (Burrows, Abadi, and Needham) logic. The proposed scheme is also comparable in terms of computational overheads with relevant schemes.

  13. Suitable scheme study of Chinese Building Energy Efficiency CDM Projects

    NASA Astrophysics Data System (ADS)

    Huang, Beijia; Yang, Haizhen; Wang, Shaoping; Wang, Feng

    2010-11-01

    China has great potential to develop Building Energy Efficiency Clean Development Mechanism (BEE CDM) projects, although have many challenges. Our results show that large-scale public buildings and urban residential buildings have relatively high BEE CDM potential, when comparing their characteristics to the CDM project requirements. The building enclosure, illumination energy conservation, air condition energy saving, solar thermal, and solar photovoltaic technology have relatively high application potential while considering the energy saving potential and marginal emission reduction cost. Case study of large-scale buildings shows that technology integration of building enclosure, illumination energy conservation, air condition energy saving, solar thermal can reduce required building number to 130 in order to meet the 1×105 tCO2 e/a reduction criteria. Some suggestions are also given in this paper.

  14. Risk management assessment of Health Maintenance Organisations participating in the National Health Insurance Scheme

    PubMed Central

    Campbell, Princess Christina; Korie, Patrick Chukwuemeka; Nnaji, Feziechukwu Collins

    2014-01-01

    Background: The National Health Insurance Scheme (NHIS), operated majorly in Nigeria by health maintenance organisations (HMOs), took off formally in June 2005. In view of the inherent risks in the operation of any social health insurance, it is necessary to efficiently manage these risks for sustainability of the scheme. Consequently the risk-management strategies deployed by HMOs need regular assessment. This study assessed the risk management in the Nigeria social health insurance scheme among HMOs. Materials and Methods: Cross-sectional survey of 33 HMOs participating in the NHIS. Results: Utilisation of standard risk-management strategies by the HMOs was 11 (52.6%). The other risk-management strategies not utilised in the NHIS 10 (47.4%) were risk equalisation and reinsurance. As high as 11 (52.4%) of participating HMOs had a weak enrollee base (less than 30,000 and poor monthly premium and these impacted negatively on the HMOs such that a large percentage 12 (54.1%) were unable to meet up with their financial obligations. Most of the HMOs 15 (71.4%) participated in the Millennium development goal (MDG) maternal and child health insurance programme. Conclusions: Weak enrollee base and poor monthly premium predisposed the HMOs to financial risk which impacted negatively on the overall performance in service delivery in the NHIS, further worsened by the non-utilisation of risk equalisation and reinsurance as risk-management strategies in the NHIS. There is need to make the scheme compulsory and introduce risk equalisation and reinsurance. PMID:25298605

  15. Efficiently Multi-User Searchable Encryption Scheme with Attribute Revocation and Grant for Cloud Storage

    PubMed Central

    Wang, Shangping; Zhang, Xiaoxue; Zhang, Yaling

    2016-01-01

    Cipher-policy attribute-based encryption (CP-ABE) focus on the problem of access control, and keyword-based searchable encryption scheme focus on the problem of finding the files that the user interested in the cloud storage quickly. To design a searchable and attribute-based encryption scheme is a new challenge. In this paper, we propose an efficiently multi-user searchable attribute-based encryption scheme with attribute revocation and grant for cloud storage. In the new scheme the attribute revocation and grant processes of users are delegated to proxy server. Our scheme supports multi attribute are revoked and granted simultaneously. Moreover, the keyword searchable function is achieved in our proposed scheme. The security of our proposed scheme is reduced to the bilinear Diffie-Hellman (BDH) assumption. Furthermore, the scheme is proven to be secure under the security model of indistinguishability against selective ciphertext-policy and chosen plaintext attack (IND-sCP-CPA). And our scheme is also of semantic security under indistinguishability against chosen keyword attack (IND-CKA) in the random oracle model. PMID:27898703

  16. Efficiently Multi-User Searchable Encryption Scheme with Attribute Revocation and Grant for Cloud Storage.

    PubMed

    Wang, Shangping; Zhang, Xiaoxue; Zhang, Yaling

    2016-01-01

    Cipher-policy attribute-based encryption (CP-ABE) focus on the problem of access control, and keyword-based searchable encryption scheme focus on the problem of finding the files that the user interested in the cloud storage quickly. To design a searchable and attribute-based encryption scheme is a new challenge. In this paper, we propose an efficiently multi-user searchable attribute-based encryption scheme with attribute revocation and grant for cloud storage. In the new scheme the attribute revocation and grant processes of users are delegated to proxy server. Our scheme supports multi attribute are revoked and granted simultaneously. Moreover, the keyword searchable function is achieved in our proposed scheme. The security of our proposed scheme is reduced to the bilinear Diffie-Hellman (BDH) assumption. Furthermore, the scheme is proven to be secure under the security model of indistinguishability against selective ciphertext-policy and chosen plaintext attack (IND-sCP-CPA). And our scheme is also of semantic security under indistinguishability against chosen keyword attack (IND-CKA) in the random oracle model.

  17. From generic scheme to brand-generic scheme: Have new policy influenced the efficiency of Iranian pharmaceutical companies?

    PubMed Central

    Hashemi-Meshkini, Amir; Varmaghani, Mehdi; Yousefi, Mehdi; Yaghoubifard, Saeed; Zekri, Hedieh-Sadat; Nikfar, Shekoufeh; Kebriaeezadeh, Abbas

    2014-01-01

    Objective: Brand-generic scheme was implemented in Iran to improve the competition in the pharmaceutical market. In this study, we aim to assess if this policy had any positive effect on efficiency of Iranian pharmaceutical companies. Methods: We used data envelopment analysis to evaluate the relative efficiency of pharmaceutical companies during 1999-2008. The Wilcoxon matched-pairs signed-rank and sign tests were used to assess the difference between mean technical efficiency of companies before and after implementation of the new policy. Findings: Although the Wilcoxon matched-pairs signed-rank tests did not show any significant differences in favor of the new policy in terms of both relative and pure (managerial) technical efficiency for included companies (P = 0.079 and 0.07, respectively), but the one-sided sign test indicated that only relative pure (managerial) efficiency has been improved after this policy (P = 0.031). Conclusion: The “brand-generic scheme” does not seem to be a successful policy to improve efficiency level and prompt competition in pharmaceutical companies in Iran. To achieve this aim, consideration of infrastructural requirements including transparent and non-discriminating laws and regulations to support competition, the competitive pricing policies, the presence of international companies in the market, and full privatization of companies had to be also deeming by policy makers. PMID:25328898

  18. Efficient Buffer Management for Scalable Media-on-Demand

    NASA Astrophysics Data System (ADS)

    Waldvogel, Marcel; Deng, Wei; Janakiraman, Ramaprabhu

    2003-01-01

    Widespread availability of high-speed networks and fast, cheap computation have rendered high-quality Media-on-Demand (MoD) feasible. Research on scalable MoD has resulted in many efficient schemes that involve segmentation and asynchronous broadcast of media data, requiring clients to buffer and reorder out-of-order segments efficiently for serial playout. In such schemes, buffer space requirements run to several hundred megabytes and hence require efficient buffer management techniques involving both primary memory and secondary storage: while disk sizes have increased exponentially, access speeds have not kept pace at all. The conversion of out-of-order arrival to in-order playout suggests the use of external memory priority queues, but their content-agnostic nature prevents them from performing well under MoD loads. In this paper, we propose and evaluate a series of simple heuristic schemes which, in simulation studies and in combination with our scalable MoD scheme, achieve significant improvements in storage performance over existing schemes.

  19. An empirical extrapolation scheme for efficient treatment of induced dipoles

    NASA Astrophysics Data System (ADS)

    Simmonett, Andrew C.; Pickard, Frank C.; Ponder, Jay W.; Brooks, Bernard R.

    2016-10-01

    Many cutting edge force fields include polarization, to enhance their accuracy and range of applicability. In this work, we develop efficient strategies for the induced dipole polarization method. By fitting various orders of perturbation theory (PT) dipoles to a diverse training set, we arrive at a family of fully analytic methods — whose nth order is referred to OPTn — that span the full spectrum of polarization methods from the fast zeroth-order approach that neglects mutual dipole coupling, approaching the fully variational approach at high order. Our training set contains many difficult cases where the PT series diverges, and we demonstrate that our OPTn methods still deliver excellent results in these cases. Our tests show that the OPTn methods exhibit rapid convergence towards the exact answer with each increasing PT order. The fourth order OPT4 method, whose costs are commensurate with three iterations of the leading conjugate gradient method, is a particularly promising candidate to be used as a drop-in replacement for existing solvers without further parameterization.

  20. An efficient Quality of Service (QoS) scheme for all optical networks

    NASA Astrophysics Data System (ADS)

    Garg, Amit Kumar; Kaler, R. S.

    2011-01-01

    This paper addresses the issue of providing Quality of Service (QoS) for optical burst switching (OBS) systems. In this paper, an efficient QoS oriented integrated scheme based on Optical Burst/Circuit Switching network architecture has been proposed. The proposed scheme utilizes the modified Just-Enough-Time (JET) protocol and advanced reservation based on Linear Predictive Filter (LPF), which can provide differentiated services for optical burst switching (OBS) network. Simulation results show that the proposed scheme is reasonably better than a First Come First Served (FCFS) protocol in guaranteeing QoS of real-time traffic. Also, the results yield significant delay reduction for time-critical traffic, while maintaining the bandwidth overhead within limits. As a result, the proposed scheme has achieved QoS differentiation in terms of burst loss rate in comparison to conventional schemes.

  1. Efficient bit sifting scheme of post-processing in quantum key distribution

    NASA Astrophysics Data System (ADS)

    Li, Qiong; Le, Dan; Wu, Xianyan; Niu, Xiamu; Guo, Hong

    2015-10-01

    Bit sifting is an important step in the post-processing of quantum key distribution (QKD). Its function is to sift out the undetected original keys. The communication traffic of bit sifting has essential impact on the net secure key rate of a practical QKD system. In this paper, an efficient bit sifting scheme is presented, of which the core is a lossless source coding algorithm. Both theoretical analysis and experimental results demonstrate that the performance of the scheme is approaching the Shannon limit. The proposed scheme can greatly decrease the communication traffic of the post-processing of a QKD system, which means the proposed scheme can decrease the secure key consumption for classical channel authentication and increase the net secure key rate of the QKD system, as demonstrated by analyzing the improvement on the net secure key rate. Meanwhile, some recommendations on the application of the proposed scheme to some representative practical QKD systems are also provided.

  2. Design and analysis of a dynamic mobility management scheme for wireless mesh network.

    PubMed

    Majumder, Abhishek; Roy, Sudipta

    2013-01-01

    Seamless mobility management of the mesh clients (MCs) in wireless mesh network (WMN) has drawn a lot of attention from the research community. A number of mobility management schemes such as mesh network with mobility management (MEMO), mesh mobility management (M(3)), and wireless mesh mobility management (WMM) have been proposed. The common problem with these schemes is that they impose uniform criteria on all the MCs for sending route update message irrespective of their distinct characteristics. This paper proposes a session-to-mobility ratio (SMR) based dynamic mobility management scheme for handling both internet and intranet traffic. To reduce the total communication cost, this scheme considers each MC's session and mobility characteristics by dynamically determining optimal threshold SMR value for each MC. A numerical analysis of the proposed scheme has been carried out. Comparison with other schemes shows that the proposed scheme outperforms MEMO, M(3), and WMM with respect to total cost.

  3. Design and Analysis of a Dynamic Mobility Management Scheme for Wireless Mesh Network

    PubMed Central

    Roy, Sudipta

    2013-01-01

    Seamless mobility management of the mesh clients (MCs) in wireless mesh network (WMN) has drawn a lot of attention from the research community. A number of mobility management schemes such as mesh network with mobility management (MEMO), mesh mobility management (M3), and wireless mesh mobility management (WMM) have been proposed. The common problem with these schemes is that they impose uniform criteria on all the MCs for sending route update message irrespective of their distinct characteristics. This paper proposes a session-to-mobility ratio (SMR) based dynamic mobility management scheme for handling both internet and intranet traffic. To reduce the total communication cost, this scheme considers each MC's session and mobility characteristics by dynamically determining optimal threshold SMR value for each MC. A numerical analysis of the proposed scheme has been carried out. Comparison with other schemes shows that the proposed scheme outperforms MEMO, M3, and WMM with respect to total cost. PMID:24311982

  4. Data Recognition and Filtering Based on Efficient RFID Data Processing Control Schemes

    NASA Astrophysics Data System (ADS)

    Kung, Hsu-Yang; Kuo, Chiung-Wen; Tsai, Ching-Ping

    Radio Frequency Identification (RFID) applications have changed gradually from a single vendor and single application to being integrated into applications for supply chains. The primary function of RFID middleware is to process large amounts of data within a short period. High performance and efficiency are difficult to achieve in a RFID data processing control scheme when the volume of RFID data is large. This work is designed the core functions of RFID middleware and developed data processing control scheme that includes data recognition, data filtering and data searching processes. The control scheme for RFID data recognition is used to identify data with false positives and then to obtain corrected data objects. The data filtering control scheme is used to solve problems associated with RFID expansion under a large amount of work and data. The proposed data searching method is based on the EPC (Electronic Product Code) and uses the Hash to accelerate information filtering efficiency.

  5. A Novel Scheme for an Energy Efficient Internet of Things Based on Wireless Sensor Networks.

    PubMed

    Rani, Shalli; Talwar, Rajneesh; Malhotra, Jyoteesh; Ahmed, Syed Hassan; Sarkar, Mahasweta; Song, Houbing

    2015-11-12

    One of the emerging networking standards that gap between the physical world and the cyber one is the Internet of Things. In the Internet of Things, smart objects communicate with each other, data are gathered and certain requests of users are satisfied by different queried data. The development of energy efficient schemes for the IoT is a challenging issue as the IoT becomes more complex due to its large scale the current techniques of wireless sensor networks cannot be applied directly to the IoT. To achieve the green networked IoT, this paper addresses energy efficiency issues by proposing a novel deployment scheme. This scheme, introduces: (1) a hierarchical network design; (2) a model for the energy efficient IoT; (3) a minimum energy consumption transmission algorithm to implement the optimal model. The simulation results show that the new scheme is more energy efficient and flexible than traditional WSN schemes and consequently it can be implemented for efficient communication in the IoT.

  6. A Novel Scheme for an Energy Efficient Internet of Things Based on Wireless Sensor Networks

    PubMed Central

    Rani, Shalli; Talwar, Rajneesh; Malhotra, Jyoteesh; Ahmed, Syed Hassan; Sarkar, Mahasweta; Song, Houbing

    2015-01-01

    One of the emerging networking standards that gap between the physical world and the cyber one is the Internet of Things. In the Internet of Things, smart objects communicate with each other, data are gathered and certain requests of users are satisfied by different queried data. The development of energy efficient schemes for the IoT is a challenging issue as the IoT becomes more complex due to its large scale the current techniques of wireless sensor networks cannot be applied directly to the IoT. To achieve the green networked IoT, this paper addresses energy efficiency issues by proposing a novel deployment scheme. This scheme, introduces: (1) a hierarchical network design; (2) a model for the energy efficient IoT; (3) a minimum energy consumption transmission algorithm to implement the optimal model. The simulation results show that the new scheme is more energy efficient and flexible than traditional WSN schemes and consequently it can be implemented for efficient communication in the IoT. PMID:26569260

  7. Efficient asymmetric image authentication schemes based on photon counting-double random phase encoding and RSA algorithms.

    PubMed

    Moon, Inkyu; Yi, Faliu; Han, Mingu; Lee, Jieun

    2016-06-01

    Recently, double random phase encoding (DRPE) has been integrated with the photon counting (PC) imaging technique for the purpose of secure image authentication. In this scheme, the same key should be securely distributed and shared between the sender and receiver, but this is one of the most vexing problems of symmetric cryptosystems. In this study, we propose an efficient asymmetric image authentication scheme by combining the PC-DRPE and RSA algorithms, which solves key management and distribution problems. The retrieved image from the proposed authentication method contains photon-limited encrypted data obtained by means of PC-DRPE. Therefore, the original image can be protected while the retrieved image can be efficiently verified using a statistical nonlinear correlation approach. Experimental results demonstrate the feasibility of our proposed asymmetric image authentication method.

  8. Energy-efficient writing scheme for magnetic domain-wall motion memory

    NASA Astrophysics Data System (ADS)

    Kim, Kab-Jin; Yoshimura, Yoko; Ham, Woo Seung; Ernst, Rick; Hirata, Yuushou; Li, Tian; Kim, Sanghoon; Moriyama, Takahiro; Nakatani, Yoshinobu; Ono, Teruo

    2017-04-01

    We present an energy-efficient magnetic domain-writing scheme for domain wall (DW) motion-based memory devices. A cross-shaped nanowire is employed to inject a domain into the nanowire through current-induced DW propagation. The energy required for injecting the magnetic domain is more than one order of magnitude lower than that for the conventional field-based writing scheme. The proposed scheme is beneficial for device miniaturization because the threshold current for DW propagation scales with the device size, which cannot be achieved in the conventional field-based technique.

  9. A Dual-Mode Hybrid ARQ Scheme for Energy Efficient On-Chip Interconnects

    NASA Astrophysics Data System (ADS)

    Fu, Bo; Ampadu, Paul

    In this paper, we propose a dual-mode hybrid ARQ scheme for energy efficient on-chip communication, where the type of coding scheme can be dynamically selected based on different noise environments and reliability requirements. In order to reduce codec area overhead, a hardware sharing design method is implemented, resulting in only a minor increase in area costs compared to a single-mode system. For a given reliability requirement, the proposed error control scheme yields up to 35% energy improvement compared to previous solutions and up to 18% energy improvement compared to worst-case noise design method.

  10. Regulation control and energy management scheme for wireless power transfer

    SciTech Connect

    Miller, John M.

    2015-12-29

    Power transfer rate at a charging facility can be maximized by employing a feedback scheme. The state of charge (SOC) and temperature of the regenerative energy storage system (RESS) pack of a vehicle is monitored to determine the load due to the RESS pack. An optimal frequency that cancels the imaginary component of the input impedance for the output signal from a grid converter is calculated from the load of the RESS pack, and a frequency offset f* is made to the nominal frequency f.sub.0 of the grid converter output based on the resonance frequency of a magnetically coupled circuit. The optimal frequency can maximize the efficiency of the power transfer. Further, an optimal grid converter duty ratio d* can be derived from the charge rate of the RESS pack. The grid converter duty ratio d* regulates wireless power transfer (WPT) power level.

  11. Development of an estuarine assessment scheme for the management of a highly urbanised catchment/estuary system, Sydney estuary, Australia.

    PubMed

    Birch, G F; Gunns, T J; Chapman, D; Harrison, D

    2016-05-01

    As coastal populations increase, considerable pressures are exerted on estuarine environments. Recently, there has been a trend towards the development and use of estuarine assessment schemes as a decision support tool in the management of these environments. These schemes offer a method by which complex environmental data is converted into a readily understandable and communicable format for informed decision making and effective distribution of limited management resources. Reliability and effectiveness of these schemes are often limited due to a complex assessment framework, poor data management and use of ineffective environmental indicators. The current scheme aims to improve reliability in the reporting of estuarine condition by including a concise assessment framework, employing high-value indicators and, in a unique approach, employing fuzzy logic in indicator evaluation. Using Sydney estuary as a case study, each of the 15 sub-catchment/sub-estuary systems were assessed using the current scheme. Results identified that poor sediment quality was a significant issue in Blackwattle/Rozelle Bay, Iron Cove and Hen and Chicken Bay while poor water quality was of particular concern in Duck River, Homebush Bay and the Parramatta River. Overall results of the assessment scheme were used to prioritise the management of each sub-catchment/sub-estuary assessed with Blackwattle/Rozelle Bay, Homebush Bay, Iron Cove and Duck River considered to be in need of a high priority management response. A report card format, using letter grades, was employed to convey the results of the assessment in a readily understood manner to estuarine managers and members of the public. Letter grades also provide benchmarking and performance monitoring ability, allowing estuarine managers to set improvement targets and assesses the effectiveness of management strategies. The current assessment scheme provides an effective, integrated and consistent assessment of estuarine health and

  12. Highly efficient light management for perovskite solar cells.

    PubMed

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-06

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells.

  13. Highly efficient light management for perovskite solar cells

    PubMed Central

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-01

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells. PMID:26733112

  14. Highly efficient light management for perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-01

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells.

  15. EPPRD: An Efficient Privacy-Preserving Power Requirement and Distribution Aggregation Scheme for a Smart Grid

    PubMed Central

    Zhang, Lei; Zhang, Jing

    2017-01-01

    A Smart Grid (SG) facilitates bidirectional demand-response communication between individual users and power providers with high computation and communication performance but also brings about the risk of leaking users’ private information. Therefore, improving the individual power requirement and distribution efficiency to ensure communication reliability while preserving user privacy is a new challenge for SG. Based on this issue, we propose an efficient and privacy-preserving power requirement and distribution aggregation scheme (EPPRD) based on a hierarchical communication architecture. In the proposed scheme, an efficient encryption and authentication mechanism is proposed for better fit to each individual demand-response situation. Through extensive analysis and experiment, we demonstrate how the EPPRD resists various security threats and preserves user privacy while satisfying the individual requirement in a semi-honest model; it involves less communication overhead and computation time than the existing competing schemes. PMID:28783122

  16. EPPRD: An Efficient Privacy-Preserving Power Requirement and Distribution Aggregation Scheme for a Smart Grid.

    PubMed

    Zhang, Lei; Zhang, Jing

    2017-08-07

    A Smart Grid (SG) facilitates bidirectional demand-response communication between individual users and power providers with high computation and communication performance but also brings about the risk of leaking users' private information. Therefore, improving the individual power requirement and distribution efficiency to ensure communication reliability while preserving user privacy is a new challenge for SG. Based on this issue, we propose an efficient and privacy-preserving power requirement and distribution aggregation scheme (EPPRD) based on a hierarchical communication architecture. In the proposed scheme, an efficient encryption and authentication mechanism is proposed for better fit to each individual demand-response situation. Through extensive analysis and experiment, we demonstrate how the EPPRD resists various security threats and preserves user privacy while satisfying the individual requirement in a semi-honest model; it involves less communication overhead and computation time than the existing competing schemes.

  17. Combining modelling tools to evaluate a goose management scheme.

    PubMed

    Baveco, Johannes M; Bergjord, Anne-Kari; Bjerke, Jarle W; Chudzińska, Magda E; Pellissier, Loïc; Simonsen, Caroline E; Madsen, Jesper; Tombre, Ingunn M; Nolet, Bart A

    2017-03-01

    Many goose species feed on agricultural land, and with growing goose numbers, conflicts with agriculture are increasing. One possible solution is to designate refuge areas where farmers are paid to leave geese undisturbed. Here, we present a generic modelling tool that can be used to designate the best locations for refuges and to gauge the area needed to accommodate the geese. With a species distribution model, locations are ranked according to goose suitability. The size of the area to be designated as refuge can be chosen by including more or less suitable locations. A resource depletion model is then used to estimate whether enough resources are available within the designated refuge to accommodate all geese, taking into account the dynamics of food resources, including depletion by geese. We illustrate this with the management scheme for pink-footed goose Anser brachyrhynchus implemented in Norway. Here, all geese can be accommodated, but damage levels appear to depend on weather, land use and refuge size.

  18. Proposed CMG momentum management scheme for space station

    NASA Technical Reports Server (NTRS)

    Bishop, L. R.; Bishop, R. H.; Lindsay, K. L.

    1987-01-01

    A discrete control moment gyro (CMG) momentum management scheme (MMS) applicable to spacecraft with principal axes misalignments, such as the proposed NASA dual keel space station, is presented in this paper. The objective of the MMS is to minmize CMG angular momentum storage requirements for maintaining the space station near local vertical in the presence of environmental disturbances. It utilizes available environmental disturbances, namely gravity gradient torques, to minimize CMG momentum storage. The MMS is executed once per orbit and generates a commanded torque equilibrium attitude (TEA) time history which consists of a yaw, pitch and roll angle command profile. Although the algorithm is called only once per orbit to compute the TEA profile, the space station will maneuver several discrete times each orbit.

  19. A proposed group management scheme for XTP multicast

    NASA Technical Reports Server (NTRS)

    Dempsey, Bert J.; Weaver, Alfred C.

    1990-01-01

    The purpose of a group management scheme is to enable its associated transfer layer protocol to be responsive to user determined reliability requirements for multicasting. Group management (GM) must assist the client process in coordinating multicast group membership, allow the user to express the subset of the multicast group that a particular multicast distribution must reach in order to be successful (reliable), and provide the transfer layer protocol with the group membership information necessary to guarantee delivery to this subset. GM provides services and mechanisms that respond to the need of the client process or process level management protocols to coordinate, modify, and determine attributes of the multicast group, especially membership. XTP GM provides a link between process groups and their multicast groups by maintaining a group membership database that identifies members in a name space understood by the underlying transfer layer protocol. Other attributes of the multicast group useful to both the client process and the data transfer protocol may be stored in the database. Examples include the relative dispersion, most recent update, and default delivery parameters of a group.

  20. A Security-Awareness Virtual Machine Management Scheme Based on Chinese Wall Policy in Cloud Computing

    PubMed Central

    Gui, Xiaolin; Lin, Jiancai; Tian, Feng; Zhao, Jianqiang; Dai, Min

    2014-01-01

    Cloud computing gets increasing attention for its capacity to leverage developers from infrastructure management tasks. However, recent works reveal that side channel attacks can lead to privacy leakage in the cloud. Enhancing isolation between users is an effective solution to eliminate the attack. In this paper, to eliminate side channel attacks, we investigate the isolation enhancement scheme from the aspect of virtual machine (VM) management. The security-awareness VMs management scheme (SVMS), a VMs isolation enhancement scheme to defend against side channel attacks, is proposed. First, we use the aggressive conflict of interest relation (ACIR) and aggressive in ally with relation (AIAR) to describe user constraint relations. Second, based on the Chinese wall policy, we put forward four isolation rules. Third, the VMs placement and migration algorithms are designed to enforce VMs isolation between the conflict users. Finally, based on the normal distribution, we conduct a series of experiments to evaluate SVMS. The experimental results show that SVMS is efficient in guaranteeing isolation between VMs owned by conflict users, while the resource utilization rate decreases but not by much. PMID:24688434

  1. A security-awareness virtual machine management scheme based on Chinese wall policy in cloud computing.

    PubMed

    Yu, Si; Gui, Xiaolin; Lin, Jiancai; Tian, Feng; Zhao, Jianqiang; Dai, Min

    2014-01-01

    Cloud computing gets increasing attention for its capacity to leverage developers from infrastructure management tasks. However, recent works reveal that side channel attacks can lead to privacy leakage in the cloud. Enhancing isolation between users is an effective solution to eliminate the attack. In this paper, to eliminate side channel attacks, we investigate the isolation enhancement scheme from the aspect of virtual machine (VM) management. The security-awareness VMs management scheme (SVMS), a VMs isolation enhancement scheme to defend against side channel attacks, is proposed. First, we use the aggressive conflict of interest relation (ACIR) and aggressive in ally with relation (AIAR) to describe user constraint relations. Second, based on the Chinese wall policy, we put forward four isolation rules. Third, the VMs placement and migration algorithms are designed to enforce VMs isolation between the conflict users. Finally, based on the normal distribution, we conduct a series of experiments to evaluate SVMS. The experimental results show that SVMS is efficient in guaranteeing isolation between VMs owned by conflict users, while the resource utilization rate decreases but not by much.

  2. Analysis of Two-Phase Path Management Scheme for MPLS Traffic Engineering

    NASA Astrophysics Data System (ADS)

    Tamura, Hitomi; Kawahara, Kenji; Oie, Yuji

    Traffic Engineering (TE) is important for improving QoS in forwarding paths by efficient use of network resources. In fact, MPLS allows several detour paths to be (pre-)established for some source-destination pair as well as its primary path of minimum hops. Thus, we focus on a two-phase path management scheme using these two kinds of paths. In the first phase, each primary path is allocated to a flow on a specific source-destination pair if the path is not congested, i.e., if its utilization is less than some predetermined threshold; otherwise, as the second phase, one of the detour paths is allocated randomly if the path is available. Therefore, in this paper, we analytically evaluate this path management scheme by extending the M/M/c/c queueing system, and through some numerical results we investigate the impact of a threshold on the flow-blocking probability. Through some numerical results, we discuss the adequacy of the path management scheme for MPLS-TE.

  3. Approaches of Improving University Assets Management Efficiency

    ERIC Educational Resources Information Center

    Wang, Jingliang

    2015-01-01

    University assets management, as an important content of modern university management, is generally confronted with the issue of low efficiency. Currently, to address the problems exposed in university assets management and take appropriate modification measures is an urgent issue in front of Chinese university assets management sectors. In this…

  4. Efficient Anonymous Authentication Protocol Using Key-Insulated Signature Scheme for Secure VANET

    NASA Astrophysics Data System (ADS)

    Park, Youngho; Sur, Chul; Jung, Chae Duk; Rhee, Kyung-Hyune

    In this paper, we propose an efficient authentication protocol with conditional privacy preservation for secure vehicular communications. The proposed protocol follows the system model to issue on-the-fly anonymous public key certificates to vehicles by road-side units. In order to design an efficient message authentication protocol, we consider a key-insulated signature scheme for certifying anonymous public keys of vehicles to such a system model. We demonstrate experimental results to confirm that the proposed protocol has better performance than other protocols based on group signature schemes.

  5. A HIPAA-compliant key management scheme with revocation of authorization.

    PubMed

    Lee, Wei-Bin; Lee, Chien-Ding; Ho, Kevin I-J

    2014-03-01

    Patient control over electronic protected health information (ePHI) is one of the major concerns in the Health Insurance and Accountability Act (HIPAA). In this paper, a new key management scheme is proposed to facilitate control by providing two functionalities. First, a patient can authorize more than one healthcare institute within a designated time period to access his or her ePHIs. Second, a patient can revoke authorization and add new authorized institutes at any time as necessary. In the design, it is not required to re-encrypt ePHIs for adding and revoking authorizations, and the implementation is time- and cost-efficient. Consent exception is also considered by the proposed scheme.

  6. Efficient storage scheme and algorithms for w-matrix vector multiplication on vector computers

    SciTech Connect

    Huang, H.S.; Lu, C.N. . Dept. of Electrical Engineering)

    1994-05-01

    The W-matrix method has been proposed in many literatures to exploit parallelism in the solution of many power system problems. This paper presents a storage scheme for storing the sparse W-matrix in solving linear equations on vector computers. Based on the proposed storage scheme, several efficient algorithms have been developed to perform the W-matrix vector multiplication for finding linear system solution. In this paper, attention is given to the issues of vector length, data movement between vector registers and memory, and the vector stride. The proposed storage scheme and algorithms are tested on Convex 3840 and Alliant FX/80 vector machines. It is shown that a speedup of two to four times is obtainable as compared to traditional scalar operation. The proposed storage scheme and algorithms can be applied to power system problems that require repeat solutions of linear system, such as load flow, contingency analysis, fast decoupled state estimation and short circuit calculations.

  7. An efficient anonymous authentication scheme for wireless body area networks using elliptic curve cryptosystem.

    PubMed

    Zhao, Zhenguo

    2014-02-01

    With the development of wireless networks and medical sensors, wireless body area networks are playing more and more important role in the field of healthcare service. The data transmitted in WBANs is very sensitive since it will be used in clinical diagnoses or measurements. Therefore, security and privacy of communication in WBANs derive increasing attentions from the academia and industry. In this paper, we propose an identity (ID)-based efficient anonymous authentication scheme for WBANs using elliptic curve cryptosystem (ECC). Due to the ID-based concept, there is no certificate is needed in the proposed scheme. Moreover, the proposed scheme not only provides mutual authentication between the client and the application provider but also provides client anonymity. Performance analysis shows that improvements of 50.58% and 3.87% in the client side and the application provider side separately. Then the proposed scheme is more suitable for WBANs.

  8. An efficient selective-repeat ARQ scheme for satellite channels and its throughput analysis

    NASA Astrophysics Data System (ADS)

    Yu, P. S.; Lin, S.

    1981-03-01

    A selective-repeat automatic repeat request (ARQ) scheme which operates with a finite receiver buffer and a finite range of sequence numbers is investigated. The throughput performance of the proposed scheme is analyzed and simulated based on the assumption that the channel errors are randomly distributed and the return channel is noiseless. Both analytical and simulation results show that it significantly outperforms the go-back-N ARQ scheme, particularly for channels with large roundtrip delay and high data rate. It provides high throughput efficiency over a wide range of bit error rates. The throughput remains in a usable range even for very high error rate conditions. The proposed scheme is capable of handling data and/or acknowledgment loss. Furthermore, when buffer overflow occurs at the receiver, the transmitter is capable of detecting it and backs up to the proper location of the input queue to retransmit the correct data blocks.

  9. Efficient and accurate numerical schemes for a hydro-dynamically coupled phase field diblock copolymer model

    NASA Astrophysics Data System (ADS)

    Cheng, Qing; Yang, Xiaofeng; Shen, Jie

    2017-07-01

    In this paper, we consider numerical approximations of a hydro-dynamically coupled phase field diblock copolymer model, in which the free energy contains a kinetic potential, a gradient entropy, a Ginzburg-Landau double well potential, and a long range nonlocal type potential. We develop a set of second order time marching schemes for this system using the ;Invariant Energy Quadratization; approach for the double well potential, the projection method for the Navier-Stokes equation, and a subtle implicit-explicit treatment for the stress and convective term. The resulting schemes are linear and lead to symmetric positive definite systems at each time step, thus they can be efficiently solved. We further prove that these schemes are unconditionally energy stable. Various numerical experiments are performed to validate the accuracy and energy stability of the proposed schemes.

  10. Efficient difference schemes for the three-phase non-isothermal flow problem

    NASA Astrophysics Data System (ADS)

    Zhumagulov, Bakytzhan; Temirbekov, Nurlan; Baigereyev, Dossan

    2017-09-01

    The paper focuses on constructing and investigation of cost-effective difference schemes for the numerical solution of the two-dimensional three-phase non-isothermal flow problem without capillary and gravitational forces. In this paper, the finite difference method is used to solve the problem numerically. The method of energy inequalities is applied to examine the stability of the finite difference scheme with respect to the initial data and the right-hand sides of the equations. Three cost-effective difference schemes are constructed on the base of the studied scheme. The efficiency of the proposed algorithms is analyzed on the basis of comparing the average time spent on the numerical implementation of one time layer.

  11. Designing Pay-As-You-Throw schemes in municipal waste management services: A holistic approach

    SciTech Connect

    Elia, Valerio; Gnoni, Maria Grazia Tornese, Fabiana

    2015-10-15

    Highlights: • Pay-As-You-Throw (PAYT) schemes are becoming widespread in several countries. • Economic, organizational and technological issues have to be integrated in an efficient PAYT model design. • Efficiency refers to a PAYT system which support high citizen participation rates as well as economic sustainability. • Different steps and constraints have to be evaluated from collection services to type technologies. • An holistic approach is discussed to support PAYT systems diffusion. - Abstract: Pay-As-You-Throw (PAYT) strategies are becoming widely applied in solid waste management systems; the main purpose is to support a more sustainable – from economic, environmental and social points of view – management of waste flows. Adopting PAYT charging models increases the complexity level of the waste management service as new organizational issues have to be evaluated compared to flat charging models. In addition, innovative technological solutions could also be adopted to increase the overall efficiency of the service. Unit pricing, user identification and waste measurement represent the three most important processes to be defined in a PAYT system. The paper proposes a holistic framework to support an effective design and management process. The framework defines most critical processes and effective organizational and technological solutions for supporting waste managers as well as researchers.

  12. Implementation of Elastic Prestack Reverse-Time Migration Using an Efficient Finite-Difference Scheme

    NASA Astrophysics Data System (ADS)

    Yan, Hongyong; Yang, Lei; Dai, Hengchang; Li, Xiang-Yang

    2016-10-01

    Elastic reverse-time migration (RTM) can reflect the underground elastic information more comprehensively than single-component Pwave migration. One of the most important requirements of elastic RTM is to solve wave equations. The imaging accuracy and efficiency of RTM depends heavily on the algorithms used for solving wave equations. In this paper, we propose an efficient staggered-grid finite-difference (SFD) scheme based on a sampling approximation method with adaptive variable difference operator lengths to implement elastic prestack RTM. Numerical dispersion analysis and wavefield extrapolation results show that the sampling approximation SFD scheme has greater accuracy than the conventional Taylor-series expansion SFD scheme. We also test the elastic RTM algorithm on theoretical models and a field data set, respectively. Experiments presented demonstrate that elastic RTM using the proposed SFD scheme can generate better images than that using the Taylor-series expansion SFD scheme, particularly for PS images. FurH. thermore, the application of adaptive variable difference operator lengths can effectively improve the computational efficiency of elastic RTM.

  13. An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks.

    PubMed

    Salim, Shelly; Moh, Sangman

    2016-06-30

    A cognitive radio sensor network (CRSN) is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD) scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead.

  14. An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks

    PubMed Central

    Salim, Shelly; Moh, Sangman

    2016-01-01

    A cognitive radio sensor network (CRSN) is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD) scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead. PMID:27376290

  15. Efficient implementation of essentially non-oscillatory shock capturing schemes, 2

    NASA Technical Reports Server (NTRS)

    Shu, Chi-Wang; Osher, Stanley

    1988-01-01

    Earlier work on the efficient implementation of ENO (essentially non-oscillatory) shock capturing schemes is continued. A new simplified expression is provided for the ENO construction procedure based again on numerical fluxes rather than cell averages. Also considered are two improvements which are labeled ENO-LLF (local Lax-Friedrichs) and ENO-Roe, which yield sharper shock transitions, improved overall efficiency, and lower computational cost than previous implementation of the ENO schemes. Two methods of sharpening contact discontinuities, i.e., the subcell resolution idea of Harten and the artificial compression idea of Yang, which those authors used originally in the cell-average framework, are supplied to the current ENO schemes using numerical fluxes and TVD Runge-Kutta time discretizations. The implementation for nonlinear systems and multi-dimensions is given. Finally, many numerical examples, including a compressible shock turbulence interaction flow calculation, are given.

  16. An efficient and provably-secure certificateless public key encryption scheme for telecare medicine information systems.

    PubMed

    Guo, Rui; Wen, Qiaoyan; Shi, Huixian; Jin, Zhengping; Zhang, Hua

    2013-10-01

    Telecare Medicine Information Systems (TMIS) promote the traditional medical and healthcare services by information and communication technology. Since the physician and caregiver can monitor the patient's physiological condition remotely in TMIS, the confidentiality of this sensitive data should be protected, which is the key issue in the Health Insurance Portability and Accountability Act. In this paper, we propose an efficient certificateless public key encryption scheme without bilinear pairing for TMIS. Our proposal is proved to be secure in the random oracle model under the hardness assumption of computational Diffie-Hellman problem. Moreover, after modifying the original model of the certificateless encryption, this scheme achieves Girault's trust level 3. Compared with the related protocols, the perform evaluations show that our scheme is more efficient and appropriate to collocate with low power mobile devices for TMIS.

  17. Smart LED allocation scheme for efficient multiuser visible light communication networks.

    PubMed

    Sewaiwar, Atul; Tiwari, Samrat Vikramaditya; Chung, Yeon Ho

    2015-05-18

    In a multiuser bidirectional visible light communication (VLC), a large number of LEDs or an LED array needs to be allocated in an efficient manner to ensure sustainable data rate and link quality. Moreover, in order to support an increasing or decreasing number of users in the network, the LED allocation is required to be performed dynamically. In this paper, a novel smart LED allocation scheme for efficient multiuser VLC networks is presented. The proposed scheme allocates RGB LEDs to multiple users in a dynamic and efficient fashion, while satisfying illumination requirements in an indoor environment. The smart LED array comprised of RGB LEDs is divided into sectors according to the location of the users. The allocated sectors then provide optical power concentration toward the users for efficient and reliable data transmission. An algorithm for the dynamic allocation of the LEDs is also presented. To verify its effective resource allocation feature of the proposed scheme, simulations were performed. It is found that the proposed smart LED allocation scheme provides the effect of optical beamforming toward individual users, thereby increasing the collective power concentration of the optical signals on the desirable users and resulting in significantly increased data rate, while ensuring sufficient illumination in a multiuser VLC environment.

  18. Strategies for implementing genomic selection for feed efficiency in dairy cattle breeding schemes.

    PubMed

    Wallén, S E; Lillehammer, M; Meuwissen, T H E

    2017-08-01

    Alternative genomic selection and traditional BLUP breeding schemes were compared for the genetic improvement of feed efficiency in simulated Norwegian Red dairy cattle populations. The change in genetic gain over time and achievable selection accuracy were studied for milk yield and residual feed intake, as a measure of feed efficiency. When including feed efficiency in genomic BLUP schemes, it was possible to achieve high selection accuracies for genomic selection, and all genomic BLUP schemes gave better genetic gain for feed efficiency than BLUP using a pedigree relationship matrix. However, introducing a second trait in the breeding goal caused a reduction in the genetic gain for milk yield. When using contracted test herds with genotyped and feed efficiency recorded cows as a reference population, adding an additional 4,000 new heifers per year to the reference population gave accuracies that were comparable to a male reference population that used progeny testing with 250 daughters per sire. When the test herd consisted of 500 or 1,000 cows, lower genetic gain was found than using progeny test records to update the reference population. It was concluded that to improve difficult to record traits, the use of contracted test herds that had additional recording (e.g., measurements required to calculate feed efficiency) is a viable option, possibly through international collaborations. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  19. A power-efficient ZF precoding scheme for multi-user indoor visible light communication systems

    NASA Astrophysics Data System (ADS)

    Zhao, Qiong; Fan, Yangyu; Deng, Lijun; Kang, Bochao

    2017-02-01

    In this study, we propose a power-efficient ZF precoding scheme for visible light communication (VLC) downlink multi-user multiple-input-single-output (MU-MISO) systems, which incorporates the zero-forcing (ZF) and the characteristics of VLC systems. The main idea of this scheme is that the channel matrix used to perform pseudoinverse comes from the set of optical Access Points (APs) shared by more than one user, instead of the set of all involved serving APs as the existing ZF precoding schemes often used. By doing this, the waste of power, which is caused by the transmission of one user's data in the un-serving APs, can be avoided. In addition, the size of the channel matrix needs to perform pseudoinverse becomes smaller, which helps to reduce the computation complexity. Simulation results in two scenarios show that the proposed ZF precoding scheme has higher power efficiency, better bit error rate (BER) performance and lower computation complexity compared with traditional ZF precoding schemes.

  20. Efficient decoupling schemes with bounded controls based on Eulerian orthogonal arrays

    SciTech Connect

    Wocjan, Pawel

    2006-06-15

    The task of decoupling, i.e., removing unwanted internal couplings of a quantum system and its couplings to an environment, plays an important role in quantum control theory. There are many efficient decoupling schemes based on combinatorial concepts such as orthogonal arrays, difference schemes, and Hadamard matrices. So far these combinatorial decoupling schemes have relied on the ability to effect sequences of instantaneous, arbitrarily strong control Hamiltonians (bang-bang controls). To overcome the shortcomings of bang-bang control, Viola and Knill proposed a method called 'Eulerian decoupling' that allows the use of bounded-strength controls for decoupling. However, their method was not directly designed to take advantage of the local structure of internal couplings and couplings to an environment that typically occur in multipartite quantum systems. In this paper we define a combinatorial structure called Eulerian orthogonal array. It merges the desirable properties of orthogonal arrays and Eulerian cycles in Cayley graphs (that are the basis of Eulerian decoupling). We show that this structure gives rise to decoupling schemes with bounded-strength control Hamiltonians that can be used to remove both internal couplings and couplings to an environment of a multipartite quantum system. Furthermore, we show how to construct Eulerian orthogonal arrays having good parameters in order to obtain efficient decoupling schemes.

  1. The experience of irrigation management transfer in two irrigation schemes in Malawi, 1960s 2002

    NASA Astrophysics Data System (ADS)

    Nkhoma, Bryson G.; Mulwafu, Wapulumuka O.

    This study examines the process of irrigation management transfer (IMT) in Malawi using the case studies of Likangala and Domasi irrigation schemes in the lake Chilwa basin. It observes that the concept of irrigation management transfer has been adopted against the background of poor performance of irrigation schemes in Malawi and the desire of the state to conform to global trends and approaches in the management of irrigation schemes. In the context of Malawi, the process of IMT involves rehabilitation of schemes and training of farmers before handing them over. The paper notes that so far the handover process has been fraught with many challenges, not least of which includes lack of adequate funds, delays, lack of public awareness and farmers’ conflicting perceptions on the handover of irrigation schemes. These problems militate against the success of IMT in the Domasi and Likangala irrigation schemes in particular and other schemes in the country as a whole.

  2. An Energy Efficient Mutual Authentication and Key Agreement Scheme Preserving Anonymity for Wireless Sensor Networks.

    PubMed

    Lu, Yanrong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2016-06-08

    WSNs (Wireless sensor networks) are nowadays viewed as a vital portion of the IoTs (Internet of Things). Security is a significant issue in WSNs, especially in resource-constrained environments. AKA (Authentication and key agreement) enhances the security of WSNs against adversaries attempting to get sensitive sensor data. Various AKA schemes have been developed for verifying the legitimate users of a WSN. Firstly, we scrutinize Amin-Biswas's currently scheme and demonstrate the major security loopholes in their works. Next, we propose a lightweight AKA scheme, using symmetric key cryptography based on smart card, which is resilient against all well known security attacks. Furthermore, we prove the scheme accomplishes mutual handshake and session key agreement property securely between the participates involved under BAN (Burrows, Abadi and Needham) logic. Moreover, formal security analysis and simulations are also conducted using AVISPA(Automated Validation of Internet Security Protocols and Applications) to show that our scheme is secure against active and passive attacks. Additionally, performance analysis shows that our proposed scheme is secure and efficient to apply for resource-constrained WSNs.

  3. An Energy Efficient Mutual Authentication and Key Agreement Scheme Preserving Anonymity for Wireless Sensor Networks

    PubMed Central

    Lu, Yanrong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2016-01-01

    WSNs (Wireless sensor networks) are nowadays viewed as a vital portion of the IoTs (Internet of Things). Security is a significant issue in WSNs, especially in resource-constrained environments. AKA (Authentication and key agreement) enhances the security of WSNs against adversaries attempting to get sensitive sensor data. Various AKA schemes have been developed for verifying the legitimate users of a WSN. Firstly, we scrutinize Amin-Biswas’s currently scheme and demonstrate the major security loopholes in their works. Next, we propose a lightweight AKA scheme, using symmetric key cryptography based on smart card, which is resilient against all well known security attacks. Furthermore, we prove the scheme accomplishes mutual handshake and session key agreement property securely between the participates involved under BAN (Burrows, Abadi and Needham) logic. Moreover, formal security analysis and simulations are also conducted using AVISPA(Automated Validation of Internet Security Protocols and Applications) to show that our scheme is secure against active and passive attacks. Additionally, performance analysis shows that our proposed scheme is secure and efficient to apply for resource-constrained WSNs. PMID:27338382

  4. Efficiency Management in Spaceflight Systems

    NASA Technical Reports Server (NTRS)

    Murphy, Karen

    2016-01-01

    Efficiency in spaceflight is often approached as “faster, better, cheaper – pick two”. The high levels of performance and reliability required for each mission suggest that planners can only control for two of the three. True efficiency comes by optimizing a system across all three parameters. The functional processes of spaceflight become technical requirements on three operational groups during mission planning: payload, vehicle, and launch operations. Given the interrelationships among the functions performed by the operational groups, optimizing function resources from one operational group to the others affects the efficiency of those groups and therefore the mission overall. This paper helps outline this framework and creates a context in which to understand the effects of resource trades on the overall system, improving the efficiency of the operational groups and the mission as a whole. This allows insight into and optimization of the controlling factors earlier in the mission planning stage.

  5. Efficiency Management in Spaceflight Systems

    NASA Technical Reports Server (NTRS)

    Murphy, Karen

    2016-01-01

    Efficiency in spaceflight is often approached as "faster, better, cheaper - pick two". The high levels of performance and reliability required for each mission suggest that planners can only control for two of the three. True efficiency comes by optimizing a system across all three parameters. The functional processes of spaceflight become technical requirements on three operational groups during mission planning: payload, vehicle, and launch operations. Given the interrelationships among the functions performed by the operational groups, optimizing function resources from one operational group to the others affects the efficiency of those groups and therefore the mission overall. This paper helps outline this framework and creates a context in which to understand the effects of resource trades on the overall system, improving the efficiency of the operational groups and the mission as a whole. This allows insight into and optimization of the controlling factors earlier in the mission planning stage.

  6. Resource allocation for efficient environmental management.

    PubMed

    McCarthy, Michael A; Thompson, Colin J; Hauser, Cindy; Burgman, Mark A; Possingham, Hugh P; Moir, Melinda L; Tiensin, Thanawat; Gilbert, Marius

    2010-10-01

    Environmental managers must decide how to invest available resources. Researchers have previously determined how to allocate conservation resources among regions, design nature reserves, allocate funding to species conservation programs, design biodiversity surveys and monitoring programs, manage species and invest in greenhouse gas mitigation schemes. However, these issues have not been addressed with a unified theory. Furthermore, uncertainty is prevalent in environmental management, and needs to be considered to manage risks. We present a theory for optimal environmental management, synthesizing previous approaches to the topic and incorporating uncertainty. We show that the theory solves a diverse range of important problems of resource allocation, including distributing conservation resources among the world's biodiversity hotspots; surveillance to detect the highly pathogenic avian influenza H5N1 virus in Thailand; and choosing survey methods for the insect order Hemiptera. Environmental management decisions are similar to decisions about financial investments, with trade-offs between risk and reward.

  7. A High Efficiency Boost Converter with MPPT Scheme for Low Voltage Thermoelectric Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Guan, Mingjie; Wang, Kunpeng; Zhu, Qingyuan; Liao, Wei-Hsin

    2016-11-01

    Using thermoelectric elements to harvest energy from heat has been of great interest during the last decade. This paper presents a direct current-direct current (DC-DC) boost converter with a maximum power point tracking (MPPT) scheme for low input voltage thermoelectric energy harvesting applications. Zero current switch technique is applied in the proposed MPPT scheme. Theoretical analysis on the converter circuits is explored to derive the equations for parameters needed in the design of the boost converter. Simulations and experiments are carried out to verify the theoretical analysis and equations. A prototype of the designed converter is built using discrete components and a low-power microcontroller. The results show that the designed converter can achieve a high efficiency at low input voltage. The experimental efficiency of the designed converter is compared with a commercial converter solution. It is shown that the designed converter has a higher efficiency than the commercial solution in the considered voltage range.

  8. A secure and efficient password-based user authentication scheme using smart cards for the integrated EPR information system.

    PubMed

    Lee, Tian-Fu; Chang, I-Pin; Lin, Tsung-Hung; Wang, Ching-Cheng

    2013-06-01

    The integrated EPR information system supports convenient and rapid e-medicine services. A secure and efficient authentication scheme for the integrated EPR information system provides safeguarding patients' electronic patient records (EPRs) and helps health care workers and medical personnel to rapidly making correct clinical decisions. Recently, Wu et al. proposed an efficient password-based user authentication scheme using smart cards for the integrated EPR information system, and claimed that the proposed scheme could resist various malicious attacks. However, their scheme is still vulnerable to lost smart card and stolen verifier attacks. This investigation discusses these weaknesses and proposes a secure and efficient authentication scheme for the integrated EPR information system as alternative. Compared with related approaches, the proposed scheme not only retains a lower computational cost and does not require verifier tables for storing users' secrets, but also solves the security problems in previous schemes and withstands possible attacks.

  9. Efficient low-storage Runge-Kutta schemes with optimized stability regions

    NASA Astrophysics Data System (ADS)

    Niegemann, Jens; Diehl, Richard; Busch, Kurt

    2012-01-01

    A variety of numerical calculations, especially when considering wave propagation, are based on the method-of-lines, where time-dependent partial differential equations (PDEs) are first discretized in space. For the remaining time-integration, low-storage Runge-Kutta schemes are particularly popular due to their efficiency and their reduced memory requirements. In this work, we present a numerical approach to generate new low-storage Runge-Kutta (LSRK) schemes with optimized stability regions for advection-dominated problems. Adapted to the spectral shape of a given physical problem, those methods are found to yield significant performance improvements over previously known LSRK schemes. As a concrete example, we present time-domain calculations of Maxwell's equations in fully three-dimensional systems, discretized by a discontinuous Galerkin approach.

  10. Application of an efficient hybrid scheme for aeroelastic analysis of advanced propellers

    NASA Technical Reports Server (NTRS)

    Srivastava, R.; Sankar, N. L.; Reddy, T. S. R.; Huff, D. L.

    1989-01-01

    An efficient 3-D hybrid scheme is applied for solving Euler equations to analyze advanced propellers. The scheme treats the spanwise direction semi-explicitly and the other two directions implicitly, without affecting the accuracy, as compared to a fully implicit scheme. This leads to a reduction in computer time and memory requirement. The calculated power coefficients for two advanced propellers, SR3 and SR7L, and various advanced ratios showed good correlation with experiment. Spanwise distribution of elemental power coefficient and steady pressure coefficient differences also showed good agreement with experiment. A study of the effect of structural flexibility on the performance of the advanced propellers showed that structural deformation due to centrifugal and aero loading should be included for better correlation.

  11. A scalable key management scheme with minimizing rekey cost for secure multicast over satellite networks

    NASA Astrophysics Data System (ADS)

    Gao, Junwei; Yang, Zongkai; Xie, Haitao

    2007-11-01

    Satellite networks are playing a more and more important role in network infrastructure. They are useful in providing broadband connectivity to remote locations which are harder to reach through terrestrial infrastructure. Data confidentiality and integrity are two critical issues for satellite networks. The multicast traffic should be accessible only to subscribers, this requires security and efficient methods to generate, distribute and update the keys. Access control can be achieved by data encryption, such as end to end security mechanisms----IPSec. Due to the high rekeying cost, most current key management protocols do not scale well for secure multicast over satellite networks. In this article we proposed a scalable key management scheme to provide secure communication in satellite networks with minimal key management overhead. The principle of this approach is to break up IPSec encryption into multiple encryption zones on a single packet and encrypts different regions of the IP packet using different keys. All of those keys are composed into just only one multi group key tree for secure multicast over satellite networks. The proposed scheme can reduce the communication and storage overhead significantly. In addition, the proposed key graph is scalable well.

  12. Efficient, high accuracy ADER-WENO schemes for hydrodynamics and divergence-free magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Balsara, Dinshaw S.; Rumpf, Tobias; Dumbser, Michael; Munz, Claus-Dieter

    2009-04-01

    The present paper introduces a class of finite volume schemes of increasing order of accuracy in space and time for hyperbolic systems that are in conservation form. The methods are specially suited for efficient implementation on structured meshes. The hyperbolic system is required to be non-stiff. This paper specifically focuses on Euler system that is used for modeling the flow of neutral fluids and the divergence-free, ideal magnetohydrodynamics (MHD) system that is used for large scale modeling of ionized plasmas. Efficient techniques for weighted essentially non-oscillatory (WENO) interpolation have been developed for finite volume reconstruction on structured meshes. We have shown that the most elegant and compact formulation of WENO reconstruction obtains when the interpolating functions are expressed in modal space. Explicit formulae have been provided for schemes having up to fourth order of spatial accuracy. Divergence-free evolution of magnetic fields requires the magnetic field components and their moments to be defined in the zone faces. We draw on a reconstruction strategy developed recently by the first author to show that a high order specification of the magnetic field components in zone-faces naturally furnishes an appropriately high order representation of the magnetic field within the zone. We also present a new formulation of the ADER (for Arbitrary Derivative Riemann Problem) schemes that relies on a local continuous space-time Galerkin formulation instead of the usual Cauchy-Kovalewski procedure. We call such schemes ADER-CG and show that a very elegant and compact formulation results when the scheme is formulated in modal space. Explicit formulae have been provided on structured meshes for ADER-CG schemes in three dimensions for all orders of accuracy that extend up to fourth order. Such ADER schemes have been used to temporally evolve the WENO-based spatial reconstruction. The resulting ADER-WENO schemes provide temporal accuracy that

  13. Efficiency of an enhanced linear optical Bell-state measurement scheme with realistic imperfections

    NASA Astrophysics Data System (ADS)

    Wein, Stephen; Heshami, Khabat; Fuchs, Christopher A.; Krovi, Hari; Dutton, Zachary; Tittel, Wolfgang; Simon, Christoph

    2016-09-01

    We compare the standard 50%-efficient single beam splitter method for Bell-state measurement to a proposed 75%-efficient auxiliary-photon-enhanced scheme [W. P. Grice, Phys. Rev. A 84, 042331 (2011), 10.1103/PhysRevA.84.042331] in light of realistic conditions. The two schemes are compared with consideration for high input state photon loss, auxiliary state photon loss, detector inefficiency and coupling loss, detector dark counts, and non-number-resolving detectors. We also analyze the two schemes when multiplexed arrays of non-number-resolving detectors are used. Furthermore, we explore the possibility of utilizing spontaneous parametric down-conversion as the auxiliary photon pair source required by the enhanced scheme. In these different cases, we determine the bounds on the detector parameters at which the enhanced scheme becomes superior to the standard scheme and describe the impact of the different imperfections on measurement success rate and discrimination fidelity. This is done using a combination of numeric and analytic techniques. For many of the cases discussed, the size of the Hilbert space and the number of measurement outcomes can be very large, which makes direct numerical solutions computationally costly. To alleviate this problem, all of our numerical computations are performed using pure states. This requires tracking the loss modes until measurement and treating dark counts as variations on measurement outcomes rather than modifications to the state itself. In addition, we provide approximate analytic expressions that illustrate the effect of different imperfections on the Bell-state analyzer quality.

  14. Goose management schemes to resolve conflicts with agriculture: Theory, practice and effects.

    PubMed

    Eythórsson, Einar; Tombre, Ingunn M; Madsen, Jesper

    2017-03-01

    In 2012, the four countries hosting the Svalbard population of pink-footed goose Anser brachyrhynchus along its flyway launched an International Species Management Plan for the population. One of the aims was to reduce conflicts between geese and agriculture to an acceptable level. Since 2006, Norway has offered subsidies to farmers that provide refuge areas for geese on their land. We evaluate the mid-Norwegian goose management subsidy scheme, with a view to its adjustment to prevailing ecological and socio-economic parameters. The analysis indicates that the legitimacy of the scheme is highly dependent on transparency of knowledge management and accountability of management scheme to the farming community. Among farmers, as well as front-line officials, outcomes of prioritisation processes within the scheme are judged unfair when there is an evident mismatch between payments and genuine damage. We suggest how the scheme can be made more fair and responsive to ecological changes, within a framework of adaptive management.

  15. High efficient key-insulated attribute based encryption scheme without bilinear pairing operations.

    PubMed

    Hong, Hanshu; Sun, Zhixin

    2016-01-01

    Attribute based encryption (ABE) has been widely applied for secure data protection in various data sharing systems. However, the efficiency of existing ABE schemes is not high enough since running encrypt and decrypt algorithms need frequent bilinear pairing operations, which may occupy too much computing resources on terminal devices. What's more, since different users may share the same attributes in the system, a single user's private key exposure will threaten the security and confidentiality of the whole system. Therefore, to further decrease the computation cost in attribute based cryptosystem as well as provide secure protection when key exposure happens, in this paper, we firstly propose a high efficient key-insulated ABE algorithm without pairings. The key-insulated mechanism guarantees both forward security and backward security when key exposure or user revocation happens. Besides, during the running of algorithms in our scheme, users and attribute authority needn't run any bilinear pairing operations, which will increase the efficiency to a large extent. The high efficiency and security analysis indicate that our scheme is more appropriate for secure protection in data sharing systems.

  16. Enhanced efficiency of plasma acceleration in the laser-induced cavity pressure acceleration scheme

    NASA Astrophysics Data System (ADS)

    Badziak, J.; Rosiński, M.; Jabłoński, S.; Pisarczyk, T.; Chodukowski, T.; Parys, P.; Rączka, P.; Krousky, E.; Ullschmied, J.; Liska, R.; Kucharik, M.

    2015-01-01

    Among various methods for the acceleration of dense plasmas the mechanism called laser-induced cavity pressure acceleration (LICPA) is capable of achieving the highest energetic efficiency. In the LICPA scheme, a projectile placed in a cavity is accelerated along a guiding channel by the laser-induced thermal plasma pressure or by the radiation pressure of an intense laser radiation trapped in the cavity. This arrangement leads to a significant enhancement of the hydrodynamic or electromagnetic forces driving the projectile, relative to standard laser acceleration schemes. The aim of this paper is to review recent experimental and numerical works on LICPA with the emphasis on the acceleration of heavy plasma macroparticles and dense ion beams. The main experimental part concerns the research carried out at the kilojoule sub-nanosecond PALS laser facility in Prague. Our measurements performed at this facility, supported by advanced two-dimensional hydrodynamic simulations, have demonstrated that the LICPA accelerator working in the long-pulse hydrodynamic regime can be a highly efficient tool for the acceleration of heavy plasma macroparticles to hyper-velocities and the generation of ultra-high-pressure (>100 Mbar) shocks through the collision of the macroparticle with a solid target. The energetic efficiency of the macroparticle acceleration and the shock generation has been found to be significantly higher than that for other laser-based methods used so far. Using particle-in-cell simulations it is shown that the LICPA scheme is highly efficient also in the short-pulse high-intensity regime and, in particular, may be used for production of intense ion beams of multi-MeV to GeV ion energies with the energetic efficiency of tens of per cent, much higher than for conventional laser acceleration schemes.

  17. Efficient and Provable Secure Pairing-Free Security-Mediated Identity-Based Identification Schemes

    PubMed Central

    Chin, Ji-Jian; Tan, Syh-Yuan; Heng, Swee-Huay; Phan, Raphael C.-W.

    2014-01-01

    Security-mediated cryptography was first introduced by Boneh et al. in 2001. The main motivation behind security-mediated cryptography was the capability to allow instant revocation of a user's secret key by necessitating the cooperation of a security mediator in any given transaction. Subsequently in 2003, Boneh et al. showed how to convert a RSA-based security-mediated encryption scheme from a traditional public key setting to an identity-based one, where certificates would no longer be required. Following these two pioneering papers, other cryptographic primitives that utilize a security-mediated approach began to surface. However, the security-mediated identity-based identification scheme (SM-IBI) was not introduced until Chin et al. in 2013 with a scheme built on bilinear pairings. In this paper, we improve on the efficiency results for SM-IBI schemes by proposing two schemes that are pairing-free and are based on well-studied complexity assumptions: the RSA and discrete logarithm assumptions. PMID:25207333

  18. An efficient numerical progressive diagonalization scheme for the quantum Rabi model revisited

    NASA Astrophysics Data System (ADS)

    Pan, Feng; Bao, Lina; Dai, Lianrong; Draayer, Jerry P.

    2017-02-01

    An efficient numerical progressive diagonalization scheme for the quantum Rabi model is revisited. The advantage of the scheme lies in the fact that the quantum Rabi model can be solved almost exactly by using the scheme that only involves a finite set of one variable polynomial equations. The scheme is especially efficient for a specified eigenstate of the model, for example, the ground state. Some low-lying level energies of the model for several sets of parameters are calculated, of which one set of the results is compared to that obtained from the Braak’s exact solution proposed recently. It is shown that the derivative of the entanglement measure defined in terms of the reduced von Neumann entropy with respect to the coupling parameter does reach the maximum near the critical point deduced from the classical limit of the Dicke model, which may provide a probe of the critical point of the crossover in finite quantum many-body systems, such as that in the quantum Rabi model.

  19. An efficient and secure medical image protection scheme based on chaotic maps.

    PubMed

    Fu, Chong; Meng, Wei-hong; Zhan, Yong-feng; Zhu, Zhi-liang; Lau, Francis C M; Tse, Chi K; Ma, Hong-feng

    2013-09-01

    Recently, the increasing demand for telemedicine services has raised interest in the use of medical image protection technology. Conventional block ciphers are poorly suited to image protection due to the size of image data and increasing demand for real-time teleradiology and other online telehealth applications. To meet this challenge, this paper presents a novel chaos-based medical image encryption scheme. To address the efficiency problem encountered by many existing permutation-substitution type image ciphers, the proposed scheme introduces a substitution mechanism in the permutation process through a bit-level shuffling algorithm. As the pixel value mixing effect is contributed by both the improved permutation process and the original substitution process, the same level of security can be achieved in a fewer number of overall rounds. The results indicate that the proposed approach provides an efficient method for real-time secure medical image transmission over public networks. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. An Efficient Scheme for Crystal Structure Prediction Based on Structural Motifs

    DOE PAGES

    Zhu, Zizhong; Wu, Ping; Wu, Shunqing; ...

    2017-05-15

    An efficient scheme based on structural motifs is proposed for the crystal structure prediction of materials. The key advantage of the present method comes in two fold: first, the degrees of freedom of the system are greatly reduced, since each structural motif, regardless of its size, can always be described by a set of parameters (R, θ, φ) with five degrees of freedom; second, the motifs could always appear in the predicted structures when the energies of the structures are relatively low. Both features make the present scheme a very efficient method for predicting desired materials. The method has beenmore » applied to the case of LiFePO4, an important cathode material for lithium-ion batteries. Numerous new structures of LiFePO4 have been found, compared to those currently available, available, demonstrating the reliability of the present methodology and illustrating the promise of the concept of structural motifs.« less

  1. On the Spectral Efficiency Limits of an OAM-Based Multiplexing Scheme

    NASA Astrophysics Data System (ADS)

    Cagliero, Andrea; Gaffoglio, Rossella

    As reported in several recent publications, a spatial multiplexing involving the transmission of orthogonal waves carrying Orbital Angular Momentum (OAM) is unable to provide improvements in spectral efficiency with respect to the conventional techniques. With this work we want to emphasize how such consideration can be easily derived from the Shannon capacity formula. Taking as a reference the performance of a multiplexing scheme based on the higher-order channel singular modes, we analyze the spectral efficiency of an OAM multi-mode transmission between antenna arrays. Our approach clearly indicates that the two techniques offer the same on-axis performance. Conversely, small misalignments in the arrays positions strongly affect the OAM scheme, highlighting the greater robustness of a traditional multiplexing method in the context of radio communications.

  2. A Study on Efficient Mobile IPv6 Fast Handover Scheme Using Reverse Binding Mechanism

    NASA Astrophysics Data System (ADS)

    Tolentino, Randy S.; Lee, Kijeong; Kim, Sung-Gyu; Kim, Miso; Park, Byungjoo

    This paper proposes a solution for solving the packet handover issues of MIPv6. We propose an efficient scheme that can support fast handover effectively in standard Mobile IPv6 (MIPv6) by optimizing the associated data and the flow of signal during handover. A new signaling message Reverse Packet Binding Mechanism is defined and utilized to hasten the handover procedure by adding a buffer in access point (AP) and home agent (HA).

  3. Search for Efficient Laser Resonance Ionization Schemes of Refractory Elements for KISS

    NASA Astrophysics Data System (ADS)

    Mukai, M.; Hirayama, Y.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Miyatake, H.; Oyaizu, M.; Watanabe, Y. X.; Kim, Y. H.; Kimura, S.

    Laser resonance ionization is employed for the element-selective ionization of multi-nucleon transfer reaction products which are stopped and neutralized in the gas cell filled with argon gas of 50 kPa. We searched for laser resonance ionization schemes of tantalum (Z = 73), tungsten (Z = 74), rhenium (Z = 75) and iridium (Z = 77) elements. We deduced the photon absorption cross section for each transition and the laser ionization efficiency in the gas cell.

  4. An efficient hybrid scheme for the analysis of counter rotating propellers

    NASA Technical Reports Server (NTRS)

    Srivastava, R.; Sankar, Lakshmi N.

    1991-01-01

    An efficient solution procedure has been developed for analyzing inviscid unsteady flow past counter rotating propellers. This scheme is first order accurate in time and second order in space, and has been extended to fourth order accuracy in the axial direction. The solution procedure has been applied to a 2-bladed SR-7 single rotation propeller and to a GE F7/A7 counter rotation propeller. The pressure coefficients and the global quantities, power and thrust, show good comparison with experimental measurements.

  5. Caseload management skills for improved efficiency.

    PubMed

    Ervin, Naomi E

    2008-03-01

    This article provides information about caseload management, which was one of a group of six competencies identified by nurse administrators as needed by new baccalaureate graduates. Caseload management is an important skill for nurses who work with caseloads of patients or clients (e.g., home health nurses, public health nurses, case managers, ambulatory care nurses). Because inadequate information about caseload management is contained in community health nursing textbooks, continuing education and staff development programs need to include caseload management skills to improve the efficiency and quality of nursing care.

  6. Efficient silvicultural practices for eastern hardwood management

    Treesearch

    Gary W. Miller; John E. Baumgras

    1994-01-01

    Eastern hardwood forests are now managed to meet a wide range of objectives, resulting in the need for silvicultural alternatives that provide timber, wildlife, aesthetics, recreation, and other benefits. However, forest management practices must continue to be efficient in terms of profiting from current harvests, protecting the environment, and sustaining production...

  7. Cap and trade schemes on waste management: a case study of the landfill allowance trading scheme (LATS) in England.

    PubMed

    Calaf-Forn, Maria; Roca, Jordi; Puig-Ventosa, Ignasi

    2014-05-01

    The Landfill Allowance Trading Scheme (LATS) is one of the main instruments used in England to enforce the landfill diversion targets established in the Directive 1999/31/EC of the European Parliament and of the Council of 26 April 1999 on the landfill of waste (Landfill Directive). Through the LATS, biodegradable municipal waste (BMW) allowances for landfilling are allocated to each local authority, otherwise known as waste disposal authorities (WDAs). The quantity of landfill allowances received is expected to decrease continuously from 2005/06 to 2019/20 so as to meet the objectives of the Landfill Directive. To achieve their commitments, WDAs can exchange, buy, sell or transfer allowances among each other, or may re-profile their own allocation through banking and/or borrowing. Despite the goals for the first seven years - which included two target years (2005/06 and 2009/10) - being widely achieved (the average allocation of allowances per WDA was 22.9% higher than those finally used), market activity among WDAs was high and prices were not very stable. Results in terms of waste reduction and recycling levels have been satisfactory. The reduction of BMW landfilled (in percentage) was higher during the first seven years of the LATS period (2005/06-2011/12) (around 7% annually) than during the previous period (2001/02-2004/05) (4.2% annually). Since 2008, the significance of the LATS diminished because of an increase in the rate of the UK Landfill Tax. The LATS was suppressed after the 2012/13 target year, before what it was initially scheduled. The purpose of this paper is to describe the particularities of the LATS, analyse its performance as a waste management policy, make a comparison with the Landfill Tax, discuss its main features as regards efficiency, effectiveness and the application of the "polluter pays" principle and finally discuss if the effect of the increase in the Landfill Tax is what made the LATS ultimately unnecessary.

  8. Energy-efficient data gathering scheme based on broadcast transmissions in wireless sensor networks.

    PubMed

    Lee, Soobin; Lee, Howon

    2013-01-01

    Improving energy efficiency is the most important challenge in wireless sensor networks. Because sensing information is correlated in many sensor network applications, some previous works have proposed ideas that reduce the energy consumption of the network by exploiting the spatial correlation between sensed information. In this paper, we propose a distributed data compression framework that exploits the broadcasting characteristic of the wireless medium to improve energy efficiency. We analyze the performance of the proposed framework numerically and compare it with the performance of previous works using simulation. The proposed scheme performs better when the sensing information is correlated.

  9. An Efficient and Practical Smart Card Based Anonymity Preserving User Authentication Scheme for TMIS using Elliptic Curve Cryptography.

    PubMed

    Amin, Ruhul; Islam, S K Hafizul; Biswas, G P; Khan, Muhammad Khurram; Kumar, Neeraj

    2015-11-01

    In the last few years, numerous remote user authentication and session key agreement schemes have been put forwarded for Telecare Medical Information System, where the patient and medical server exchange medical information using Internet. We have found that most of the schemes are not usable for practical applications due to known security weaknesses. It is also worth to note that unrestricted number of patients login to the single medical server across the globe. Therefore, the computation and maintenance overhead would be high and the server may fail to provide services. In this article, we have designed a medical system architecture and a standard mutual authentication scheme for single medical server, where the patient can securely exchange medical data with the doctor(s) via trusted central medical server over any insecure network. We then explored the security of the scheme with its resilience to attacks. Moreover, we formally validated the proposed scheme through the simulation using Automated Validation of Internet Security Schemes and Applications software whose outcomes confirm that the scheme is protected against active and passive attacks. The performance comparison demonstrated that the proposed scheme has lower communication cost than the existing schemes in literature. In addition, the computation cost of the proposed scheme is nearly equal to the exiting schemes. The proposed scheme not only efficient in terms of different security attacks, but it also provides an efficient login, mutual authentication, session key agreement and verification and password update phases along with password recovery.

  10. Efficient high-order discontinuous Galerkin schemes with first-order hyperbolic advection-diffusion system approach

    NASA Astrophysics Data System (ADS)

    Mazaheri, Alireza; Nishikawa, Hiroaki

    2016-09-01

    We propose arbitrary high-order discontinuous Galerkin (DG) schemes that are designed based on a first-order hyperbolic advection-diffusion formulation of the target governing equations. We present, in details, the efficient construction of the proposed high-order schemes (called DG-H), and show that these schemes have the same number of global degrees-of-freedom as comparable conventional high-order DG schemes, produce the same or higher order of accuracy solutions and solution gradients, are exact for exact polynomial functions, and do not need a second-derivative diffusion operator. We demonstrate that the constructed high-order schemes give excellent quality solution and solution gradients on irregular triangular elements. We also construct a Weighted Essentially Non-Oscillatory (WENO) limiter for the proposed DG-H schemes and apply it to discontinuous problems. We also make some accuracy comparisons with conventional DG and interior penalty schemes. A relative qualitative cost analysis is also reported, which indicates that the high-order schemes produce orders of magnitude more accurate results than the low-order schemes for a given CPU time. Furthermore, we show that the proposed DG-H schemes are nearly as efficient as the DG and Interior-Penalty (IP) schemes as these schemes produce results that are relatively at the same error level for approximately a similar CPU time.

  11. Developing Efficient Coordination Schemes to Control Over-Pumping in the Heihe River Basin, China

    NASA Astrophysics Data System (ADS)

    Pedrazzini, G.

    2015-12-01

    Many wicked water resources problems are approached in a social planner perspective. This not always matches the real institutional and policy-making context, where, rather, multiple decision-makers (DMs) can act independently, or weakly cooperate, ultimately producing system-wide inefficient trade-offs. The idea in this work is to adopt a more realistic approach, where the multi-DMs nature of the problem is preserved and the uncoordinated DMs are driven, thorough coordination mechanisms, towards a more system-wide efficient solution. An agent-based modelling framework linked to a surface and groundwater model is used to design these coordination mechanisms as constraints to the independent agents (i.e., DMs) behaviour. In the Heihe Basin the ongoing introduction of smart meter IC-card systems on farmers' pumping wells will soon allow monitoring and control of abstractions with the goal of preventing further depletion of the resource. The major interest of policy makers in the region concerns the development of new and the improvement of existing legislation on pricing schemes and/or groundwater quotas. The model outcome where agents act rationally but selfishly is compared to the optimal solution at system-level assuming perfect coordination and cooperation. The optimal solutions with respect to the given utility functions are computed using nonlinear optimization with a rolling out time horizon. The Pareto-Frontier is synthesized through an exhaustive sampling of the weight coefficient space and related to the current and to the historical management of the last 4 decades. The best parameter values for the proposed coordination mechanisms are determined and the alternatives are compared with respect to their efficiency and acceptability. Preliminary results suggest that a regulatory tax on groundwater of about a factor 10 of the current resource fee is required to increase the elasticity of the groundwater demand curve such that reducing consumption becomes

  12. Cap and trade schemes on waste management: A case study of the Landfill Allowance Trading Scheme (LATS) in England

    SciTech Connect

    Calaf-Forn, Maria; Roca, Jordi; Puig-Ventosa, Ignasi

    2014-05-01

    Highlights: • LATS has been effective to achieve a reduction of the amount of landfilled waste. • LATS has been one of the few environmental instruments for waste management with a cap and trade methodology. • LATS has achieved to increase recycling of the biodegradable and other waste fractions. - Abstract: The Landfill Allowance Trading Scheme (LATS) is one of the main instruments used in England to enforce the landfill diversion targets established in the Directive 1999/31/EC of the European Parliament and of the Council of 26 April 1999 on the landfill of waste (Landfill Directive). Through the LATS, biodegradable municipal waste (BMW) allowances for landfilling are allocated to each local authority, otherwise known as waste disposal authorities (WDAs). The quantity of landfill allowances received is expected to decrease continuously from 2005/06 to 2019/20 so as to meet the objectives of the Landfill Directive. To achieve their commitments, WDAs can exchange, buy, sell or transfer allowances among each other, or may re-profile their own allocation through banking and/or borrowing. Despite the goals for the first seven years – which included two target years (2005/06 and 2009/10) – being widely achieved (the average allocation of allowances per WDA was 22.9% higher than those finally used), market activity among WDAs was high and prices were not very stable. Results in terms of waste reduction and recycling levels have been satisfactory. The reduction of BMW landfilled (in percentage) was higher during the first seven years of the LATS period (2005/06–2011/12) (around 7% annually) than during the previous period (2001/02–2004/05) (4.2% annually). Since 2008, the significance of the LATS diminished because of an increase in the rate of the UK Landfill Tax. The LATS was suppressed after the 2012/13 target year, before what it was initially scheduled. The purpose of this paper is to describe the particularities of the LATS, analyse its performance as

  13. Towards an Efficient Flooding Scheme Exploiting 2-Hop Backward Information in MANETs

    NASA Astrophysics Data System (ADS)

    Le, Trong Duc; Choo, Hyunseung

    Flooding is an indispensable operation for providing control or routing functionalities to mobile ad hoc networks (MANETs). Previously, many flooding schemes have been studied with the intention of curtailing the problems of severe redundancies, contention, and collisions in traditional implementations. A recent approach with relatively high efficiency is 1HI by Liu et al., which uses only 1-hop neighbor information. The scheme achieves local optimality in terms of the number of retransmission nodes with time complexity &Theta(n log n), where n is the number of neighbors of a node; however, this method tends to make many redundant transmissions. In this paper, we present a novel flooding algorithm, 2HBI (2-hop backward information), that efficiently reduces the number of retransmission nodes and solves the broadcast storm problem in ad hoc networks using our proposed concept, “2-hop backward information.” The most significant feature of the proposed algorithm is that it does not require any extra communication overhead other than the exchange of 1-hop HELLO messages but maintains high deliverability. Comprehensive computer simulations show that the proposed scheme significantly reduces redundant transmissions in 1HI and in pure flooding, up to 38% and 91%, respectively; accordingly it alleviates contention and collisions in networks.

  14. An Efficient Scheduling Scheme for Assigning Transmission Opportunity in QoS-Guaranteed Wireless LAN

    NASA Astrophysics Data System (ADS)

    Tagashira, Shigeaki; Yamane, Masahiro; Fujita, Satoshi

    The IEEE 802.11e standard defines several important techniques that guarantee the quality of service (QoS) of multimedia communications in wireless LAN applications. A key technique introduced in the standard is an efficient media access control based on the Hybrid Coordination Function (HCF), which assigns an appropriate transmission opportunity (TXOP) to each flow for satisfying several requirements on the flow, such as delay bound and communication bandwidth. Although the simple scheduler designed in HCF could provide an efficient tool to guarantee the QoS in wireless LAN applications, it has a serious drawback, wherein a useless bandwidth assignment frequently occurs. Such assignments occur primarily due to a limitation of the scheme, wherein all the flows share the same service interval (SI). In this paper, we propose a new scheduling scheme that associates each flow with its own SI according to the hardness of the required SI. The effect of this approach is experimentally evaluated by simulation, the results of which indicate that the number of admitted flows and network resource utilization increase due to the proposed scheme.

  15. Satisfaction with the level and type of resource use of a health insurance scheme in Nigeria: health management organizations' perspectives.

    PubMed

    Mohammed, Shafiu; Souares, Aurelia; Lorenzo Bermejo, Justo; Babale, Sufiyan Muawiyyah; Sauerborn, Rainer; Dong, Hengjin

    2014-01-01

    Some developing countries have incorporated managed care elements into their national health insurance schemes. In practice, hybrid health management organizations (Hmos) are insurers who, bearing some resemblance to managed care in the USA, are vertically integrated in the scheme's revenue collection and pool and purchase healthcare services within a competitive framework. To date, few studies have focused on these organizations and their level of satisfaction with the scheme's optimal-resource-use (ORU) implementation. In Nigeria, the study site, Hmos were categorized on the basis of their satisfaction with ORU activities. One hundred forty-seven Hmo staff were randomly interviewed. The types of ORU domain categories were provider payment mechanism, administrative efficiency, benefit package inclusions and active monitoring mechanism. Bivariate analysis was used to determine differences among the Hmos' satisfaction with the various ORU domains. The Hmos' satisfaction with the health insurance scheme's ORU activities was 59.2% generally, and the associated factors were identified. According to the Hmos' perspectives related to the type of ORU, the fee-for-service payment method and regular inspection performed weakly. Hmos' limited satisfaction with the scheme's ORU raises concerns regarding ineffectiveness that may hinder implementation. To offset high risks in the scheme, it appears necessary for the regulatory agency to adapt and reform strategies of provider payment and active monitoring mechanisms according to stakeholder needs. Our findings further reveal that having Hmos evaluate ORU is useful for providing evidence-based information for policy making and regulatory utilization related to implementation of the health insurance scheme. Copyright © 2013 John Wiley & Sons, Ltd.

  16. Energy efficient in-network RFID data filtering scheme in wireless sensor networks.

    PubMed

    Bashir, Ali Kashif; Lim, Se-Jung; Hussain, Chauhdary Sajjad; Park, Myong-Soon

    2011-01-01

    RFID (Radio frequency identification) and wireless sensor networks are backbone technologies for pervasive environments. In integration of RFID and WSN, RFID data uses WSN protocols for multi-hop communications. Energy is a critical issue in WSNs; however, RFID data contains a lot of duplication. These duplications can be eliminated at the base station, but unnecessary transmissions of duplicate data within the network still occurs, which consumes nodes' energy and affects network lifetime. In this paper, we propose an in-network RFID data filtering scheme that efficiently eliminates the duplicate data. For this we use a clustering mechanism where cluster heads eliminate duplicate data and forward filtered data towards the base station. Simulation results prove that our approach saves considerable amounts of energy in terms of communication and computational cost, compared to existing filtering schemes.

  17. An efficient scheme for automatic web pages categorization using the support vector machine

    NASA Astrophysics Data System (ADS)

    Bhalla, Vinod Kumar; Kumar, Neeraj

    2016-07-01

    In the past few years, with an evolution of the Internet and related technologies, the number of the Internet users grows exponentially. These users demand access to relevant web pages from the Internet within fraction of seconds. To achieve this goal, there is a requirement of an efficient categorization of web page contents. Manual categorization of these billions of web pages to achieve high accuracy is a challenging task. Most of the existing techniques reported in the literature are semi-automatic. Using these techniques, higher level of accuracy cannot be achieved. To achieve these goals, this paper proposes an automatic web pages categorization into the domain category. The proposed scheme is based on the identification of specific and relevant features of the web pages. In the proposed scheme, first extraction and evaluation of features are done followed by filtering the feature set for categorization of domain web pages. A feature extraction tool based on the HTML document object model of the web page is developed in the proposed scheme. Feature extraction and weight assignment are based on the collection of domain-specific keyword list developed by considering various domain pages. Moreover, the keyword list is reduced on the basis of ids of keywords in keyword list. Also, stemming of keywords and tag text is done to achieve a higher accuracy. An extensive feature set is generated to develop a robust classification technique. The proposed scheme was evaluated using a machine learning method in combination with feature extraction and statistical analysis using support vector machine kernel as the classification tool. The results obtained confirm the effectiveness of the proposed scheme in terms of its accuracy in different categories of web pages.

  18. The performance evaluation of a new neural network based traffic management scheme for a satellite communication network

    NASA Technical Reports Server (NTRS)

    Ansari, Nirwan; Liu, Dequan

    1991-01-01

    A neural-network-based traffic management scheme for a satellite communication network is described. The scheme consists of two levels of management. The front end of the scheme is a derivation of Kohonen's self-organization model to configure maps for the satellite communication network dynamically. The model consists of three stages. The first stage is the pattern recognition task, in which an exemplar map that best meets the current network requirements is selected. The second stage is the analysis of the discrepancy between the chosen exemplar map and the state of the network, and the adaptive modification of the chosen exemplar map to conform closely to the network requirement (input data pattern) by means of Kohonen's self-organization. On the basis of certain performance criteria, whether a new map is generated to replace the original chosen map is decided in the third stage. A state-dependent routing algorithm, which arranges the incoming call to some proper path, is used to make the network more efficient and to lower the call block rate. Simulation results demonstrate that the scheme, which combines self-organization and the state-dependent routing mechanism, provides better performance in terms of call block rate than schemes that only have either the self-organization mechanism or the routing mechanism.

  19. The performance evaluation of a new neural network based traffic management scheme for a satellite communication network

    NASA Technical Reports Server (NTRS)

    Ansari, Nirwan; Liu, Dequan

    1991-01-01

    A neural-network-based traffic management scheme for a satellite communication network is described. The scheme consists of two levels of management. The front end of the scheme is a derivation of Kohonen's self-organization model to configure maps for the satellite communication network dynamically. The model consists of three stages. The first stage is the pattern recognition task, in which an exemplar map that best meets the current network requirements is selected. The second stage is the analysis of the discrepancy between the chosen exemplar map and the state of the network, and the adaptive modification of the chosen exemplar map to conform closely to the network requirement (input data pattern) by means of Kohonen's self-organization. On the basis of certain performance criteria, whether a new map is generated to replace the original chosen map is decided in the third stage. A state-dependent routing algorithm, which arranges the incoming call to some proper path, is used to make the network more efficient and to lower the call block rate. Simulation results demonstrate that the scheme, which combines self-organization and the state-dependent routing mechanism, provides better performance in terms of call block rate than schemes that only have either the self-organization mechanism or the routing mechanism.

  20. Efficient schemes for deterministic joint remote preparation of an arbitrary four-qubit W-type entangled state

    NASA Astrophysics Data System (ADS)

    Fu, Hao; Ma, Peng-Cheng; Chen, Gui-Bin; Li, Xiao-Wei; Zhan, You-Bang

    2017-06-01

    We present three schemes for the joint remote state preparation (JRSP) of an arbitrary four-qubit W-type entangled state with complex coefficients via four and two three-qubit GHZ states as the quantum channel. In these schemes, two senders (or N senders) share the original state which they wish to help the receiver to remotely prepare. To complete the JRSP schemes, some novel sets of mutually orthogonal basis vectors are introduced. It is shown that, only if two senders (or N senders) collaborate with each other, and perform projective measurements under suitable measuring basis on their own qubits, the receiver can reconstruct the original state by means of some appropriate unitary operations. It is shown that, in all our schemes, the total success probability of the JRSP can reach 1. Specially, compared with the first scheme in our paper, the entanglement resource in the second scheme can be reduced. This means that the scheme is more efficient and economical.

  1. A secure and efficient uniqueness-and-anonymity-preserving remote user authentication scheme for connected health care.

    PubMed

    Das, Ashok Kumar; Goswami, Adrijit

    2013-06-01

    Connected health care has several applications including telecare medicine information system, personally controlled health records system, and patient monitoring. In such applications, user authentication can ensure the legality of patients. In user authentication for such applications, only the legal user/patient himself/herself is allowed to access the remote server, and no one can trace him/her according to transmitted data. Chang et al. proposed a uniqueness-and-anonymity-preserving remote user authentication scheme for connected health care (Chang et al., J Med Syst 37:9902, 2013). Their scheme uses the user's personal biometrics along with his/her password with the help of the smart card. The user's biometrics is verified using BioHashing. Their scheme is efficient due to usage of one-way hash function and exclusive-or (XOR) operations. In this paper, we show that though their scheme is very efficient, their scheme has several security weaknesses such as (1) it has design flaws in login and authentication phases, (2) it has design flaws in password change phase, (3) it fails to protect privileged insider attack, (4) it fails to protect the man-in-the middle attack, and (5) it fails to provide proper authentication. In order to remedy these security weaknesses in Chang et al.'s scheme, we propose an improvement of their scheme while retaining the original merit of their scheme. We show that our scheme is efficient as compared to Chang et al.'s scheme. Through the security analysis, we show that our scheme is secure against possible attacks. Further, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool to ensure that our scheme is secure against passive and active attacks. In addition, after successful authentication between the user and the server, they establish a secret session key shared between them for future secure communication.

  2. Decentralising Zimbabwe’s water management: The case of Guyu-Chelesa irrigation scheme

    NASA Astrophysics Data System (ADS)

    Tambudzai, Rashirayi; Everisto, Mapedza; Gideon, Zhou

    Smallholder irrigation schemes are largely supply driven such that they exclude the beneficiaries on the management decisions and the choice of the irrigation schemes that would best suit their local needs. It is against this background that the decentralisation framework and the Dublin Principles on Integrated Water Resource Management (IWRM) emphasise the need for a participatory approach to water management. The Zimbabwean government has gone a step further in decentralising the management of irrigation schemes, that is promoting farmer managed irrigation schemes so as to ensure effective management of scarce community based land and water resources. The study set to investigate the way in which the Guyu-Chelesa irrigation scheme is managed with specific emphasis on the role of the Irrigation Management Committee (IMC), the level of accountability and the powers devolved to the IMC. Merrey’s 2008 critique of IWRM also informs this study which views irrigation as going beyond infrastructure by looking at how institutions and decision making processes play out at various levels including at the irrigation scheme level. The study was positioned on the hypothesis that ‘decentralised or autonomous irrigation management enhances the sustainability and effectiveness of irrigation schemes’. To validate or falsify the stated hypothesis, data was gathered using desk research in the form of reviewing articles, documents from within the scheme and field research in the form of questionnaire surveys, key informant interviews and field observation. The Statistical Package for Social Sciences was used to analyse data quantitatively, whilst content analysis was utilised to analyse qualitative data whereby data was analysed thematically. Comparative analysis was carried out as Guyu-Chelesa irrigation scheme was compared with other smallholder irrigation scheme’s experiences within Zimbabwe and the Sub Saharan African region at large. The findings were that whilst the

  3. My career - from a youth training scheme to practice manager.

    PubMed

    Rickard, Renay

    2017-04-01

    Renay Rickard is practice manager of Kernow Veterinary Group in Cornwall. Her entry to the veterinary profession was as a veterinary nurse, but her role evolved into a management one as the practice grew into a group. She is president of the Veterinary Practice Management Association. British Veterinary Association.

  4. A novel standby mode detection scheme with light load efficiency improvement

    NASA Astrophysics Data System (ADS)

    Hu, Jiajun; Chen, Houpeng; Wang, Qian; Li, Xi; Fan, Xi; Miao, Jie; Song, Zhitang

    2016-10-01

    A novel standby mode scheme with light load efficiency improvement is proposed in this paper, which is especially suitable for modern boost dc-dc converters powered by Li-ion battery. The proposed output load estimator is able to accurately reflect the output load current under light load condition once inductor current enters in the discontinuous conduction mode (DCM). Our experimental results show that the proposed boost dc-dc converter can automatically select approximate PWM switching frequency according to the detected information of the proposed output load estimator, regardless of power supply and inductor value.

  5. Efficient quantum secret sharing scheme with two-particle entangled states

    NASA Astrophysics Data System (ADS)

    Zhu, Zhen-Chao; Zhang, Yu-Qing; Fu, An-Min

    2011-04-01

    This paper proposes a protocol for multi-party quantum secret sharing utilizing four non-orthogonal two-particle entangled states following some ideas in the schemes proposed by Liu et al. (2006 Chin. Phys. Lett. 23 3148) and Zhang et al. (2009 Chin. Phys. B 18 2149) respectively. The theoretical efficiency for qubits of the new protocol is improved from 50% to approaching 100%. All the entangled states can be used for generating the private key except those used for the eavesdropping check. The validity of a probable attack called opaque cheat attack to this kind of protocols is considered in the paper for the first time.

  6. Efficient scheme for generation of photonic NOON states in circuit QED.

    PubMed

    Xiong, Shao-Jie; Sun, Zhe; Liu, Jin-Ming; Liu, Tong; Yang, Chui-Ping

    2015-05-15

    We propose an efficient scheme for generating photonic NOON states of two resonators coupled to a four-level superconducting flux device (coupler). This proposal operates essentially by employing a technique of a coupler resonantly interacting with two resonators simultaneously. As a consequence, the NOON-state preparation requires only N+1 operational steps and thus is much faster when compared with a recent proposal [Su et al, Sci. Rep.4, 3898 (2014)] requiring 2N steps of operation. Moreover, due to the use of only two resonators and a coupler, the experimental setup is much simplified when compared with previous proposals requiring three resonators and two superconducting qubits/qutrits.

  7. Nanooptics for high efficient photon managment

    NASA Astrophysics Data System (ADS)

    Wyrowski, Frank; Schimmel, Hagen

    2005-09-01

    Optical systems for photon management, that is the generation of tailored electromagnetic fields, constitute one of the keys for innovation through photonics. An important subfield of photon management deals with the transformation of an incident light field into a field of specified intensity distribution. In this paper we consider some basic aspects of the nature of systems for those light transformations. It turns out, that the transversal redistribution of energy (TRE) is of central concern to achieve systems with high transformation efficiency. Besides established techniques nanostructured optical elements (NOE) are demanded to implement transversal energy redistribution. That builds a bridge between the needs of photon management, optical engineering, and nanooptics.

  8. An Efficient Radial Basis Function Mesh Deformation Scheme within an Adjoint-Based Aerodynamic Optimization Framework

    NASA Astrophysics Data System (ADS)

    Poirier, Vincent

    Mesh deformation schemes play an important role in numerical aerodynamic optimization. As the aerodynamic shape changes, the computational mesh must adapt to conform to the deformed geometry. In this work, an extension to an existing fast and robust Radial Basis Function (RBF) mesh movement scheme is presented. Using a reduced set of surface points to define the mesh deformation increases the efficiency of the RBF method; however, at the cost of introducing errors into the parameterization by not recovering the exact displacement of all surface points. A secondary mesh movement is implemented, within an adjoint-based optimization framework, to eliminate these errors. The proposed scheme is tested within a 3D Euler flow by reducing the pressure drag while maintaining lift of a wing-body configured Boeing-747 and an Onera-M6 wing. As well, an inverse pressure design is executed on the Onera-M6 wing and an inverse span loading case is presented for a wing-body configured DLR-F6 aircraft.

  9. Zero modes in magnetic systems: General theory and an efficient computational scheme

    NASA Astrophysics Data System (ADS)

    Buijnsters, F. J.; Fasolino, A.; Katsnelson, M. I.

    2014-05-01

    The presence of topological defects in magnetic media often leads to normal modes with zero frequency (zero modes). Such modes are crucial for long-time behavior, describing, for example, the motion of a domain wall as a whole. Conventional numerical methods to calculate the spin-wave spectrum in magnetic media are either inefficient or they fail for systems with zero modes. We present a new efficient computational scheme that reduces the magnetic normal-mode problem to a generalized Hermitian eigenvalue problem also in the presence of zero modes. We apply our scheme to several examples, including two-dimensional domain walls and Skyrmions, and show how the effective masses that determine the dynamics can be calculated directly. These systems highlight the fundamental distinction between the two types of zero modes that can occur in spin systems, which we call special and inertial zero modes. Whereas the inertial modes are generic Goldstone modes related to a broken continuous symmetry, the special modes arise naturally when two broken continuous symmetries coexist. Our method is suitable for both conservative and dissipative systems. For the latter case, we present a perturbative scheme to take into account damping, which can also be used to calculate dynamical susceptibilities.

  10. Groupwise registration of multimodal images by an efficient joint entropy minimization scheme.

    PubMed

    Spiclin, Ziga; Likar, Bostjan; Pernus, Franjo

    2012-05-01

    Groupwise registration is concerned with bringing a group of images into the best spatial alignment. If images in the group are from different modalities, then the intensity correspondences across the images can be modeled by the joint density function (JDF) of the cooccurring image intensities. We propose a so-called treecode registration method for groupwise alignment of multimodal images that uses a hierarchical intensity-space subdivision scheme through which an efficient yet sufficiently accurate estimation of the (high-dimensional) JDF based on the Parzen kernel method is computed. To simultaneously align a group of images, a gradient-based joint entropy minimization was employed that also uses the same hierarchical intensity-space subdivision scheme. If the Hilbert kernel is used for the JDF estimation, then the treecode method requires no data-dependent bandwidth selection and is thus fully automatic. The treecode method was compared with the ensemble clustering (EC) method on four different publicly available multimodal image data sets and on a synthetic monomodal image data set. The obtained results indicate that the treecode method has similar and, for two data sets, even superior performances compared to the EC method in terms of registration error and success rate. The obtained good registration performances can be mostly attributed to the sufficiently accurate estimation of the JDF, which is computed through the hierarchical intensity-space subdivision scheme, that captures all the important features needed to detect the correct intensity correspondences across a multimodal group of images undergoing registration.

  11. Development of efficient GPU parallelization of WRF Yonsei University planetary boundary layer scheme

    NASA Astrophysics Data System (ADS)

    Huang, M.; Mielikainen, J.; Huang, B.; Chen, H.; Huang, H.-L. A.; Goldberg, M. D.

    2015-09-01

    The planetary boundary layer (PBL) is the lowest part of the atmosphere and where its character is directly affected by its contact with the underlying planetary surface. The PBL is responsible for vertical sub-grid-scale fluxes due to eddy transport in the whole atmospheric column. It determines the flux profiles within the well-mixed boundary layer and the more stable layer above. It thus provides an evolutionary model of atmospheric temperature, moisture (including clouds), and horizontal momentum in the entire atmospheric column. For such purposes, several PBL models have been proposed and employed in the weather research and forecasting (WRF) model of which the Yonsei University (YSU) scheme is one. To expedite weather research and prediction, we have put tremendous effort into developing an accelerated implementation of the entire WRF model using graphics processing unit (GPU) massive parallel computing architecture whilst maintaining its accuracy as compared to its central processing unit (CPU)-based implementation. This paper presents our efficient GPU-based design on a WRF YSU PBL scheme. Using one NVIDIA Tesla K40 GPU, the GPU-based YSU PBL scheme achieves a speedup of 193× with respect to its CPU counterpart running on one CPU core, whereas the speedup for one CPU socket (4 cores) with respect to 1 CPU core is only 3.5×. We can even boost the speedup to 360× with respect to 1 CPU core as two K40 GPUs are applied.

  12. Development of efficient GPU parallelization of WRF Yonsei University planetary boundary layer scheme

    NASA Astrophysics Data System (ADS)

    Huang, M.; Mielikainen, J.; Huang, B.; Chen, H.; Huang, H.-L. A.; Goldberg, M. D.

    2014-11-01

    The planetary boundary layer (PBL) is the lowest part of the atmosphere and where its character is directly affected by its contact with the underlying planetary surface. The PBL is responsible for vertical sub-grid-scale fluxes due to eddy transport in the whole atmospheric column. It determines the flux profiles within the well-mixed boundary layer and the more stable layer above. It thus provides an evolutionary model of atmospheric temperature, moisture (including clouds), and horizontal momentum in the entire atmospheric column. For such purposes, several PBL models have been proposed and employed in the weather research and forecasting (WRF) model of which the Yonsei University (YSU) scheme is one. To expedite weather research and prediction, we have put tremendous effort into developing an accelerated implementation of the entire WRF model using Graphics Processing Unit (GPU) massive parallel computing architecture whilst maintaining its accuracy as compared to its CPU-based implementation. This paper presents our efficient GPU-based design on WRF YSU PBL scheme. Using one NVIDIA Tesla K40 GPU, the GPU-based YSU PBL scheme achieves a speedup of 193× with respect to its Central Processing Unit (CPU) counterpart running on one CPU core, whereas the speedup for one CPU socket (4 cores) with respect to one CPU core is only 3.5×. We can even boost the speedup to 360× with respect to one CPU core as two K40 GPUs are applied.

  13. Efficient massively parallel simulation of dynamic channel assignment schemes for wireless cellular communications

    NASA Technical Reports Server (NTRS)

    Greenberg, Albert G.; Lubachevsky, Boris D.; Nicol, David M.; Wright, Paul E.

    1994-01-01

    Fast, efficient parallel algorithms are presented for discrete event simulations of dynamic channel assignment schemes for wireless cellular communication networks. The driving events are call arrivals and departures, in continuous time, to cells geographically distributed across the service area. A dynamic channel assignment scheme decides which call arrivals to accept, and which channels to allocate to the accepted calls, attempting to minimize call blocking while ensuring co-channel interference is tolerably low. Specifically, the scheme ensures that the same channel is used concurrently at different cells only if the pairwise distances between those cells are sufficiently large. Much of the complexity of the system comes from ensuring this separation. The network is modeled as a system of interacting continuous time automata, each corresponding to a cell. To simulate the model, conservative methods are used; i.e., methods in which no errors occur in the course of the simulation and so no rollback or relaxation is needed. Implemented on a 16K processor MasPar MP-1, an elegant and simple technique provides speedups of about 15 times over an optimized serial simulation running on a high speed workstation. A drawback of this technique, typical of conservative methods, is that processor utilization is rather low. To overcome this, new methods were developed that exploit slackness in event dependencies over short intervals of time, thereby raising the utilization to above 50 percent and the speedup over the optimized serial code to about 120 times.

  14. Improving resource efficiency through management science.

    PubMed

    Revere, Lee; Roberts, Ralph

    2004-01-01

    Optimal management of resources is a very complex and difficult task for healthcare systems. Nevertheless, healthcare providers can employ data-driven methodologies and management science tools, coupled with managerial insights, to significantly improve both their resource effectiveness and efficiency. Understanding the full technical complexities of management science models is a daunting task for healthcare managers, but they can be aided by the increased availability of management science software. Readily available software does not require extensive technical competencies and is easily adaptable to resource changes. This article reports how a large healthcare system improved the cost effectiveness and service efficiency of its laboratory courier service through the use of management science techniques and readily available software. The laboratory courier system existed to serve a large multihospital healthcare system located in a major Texas metropolis. The routing and scheduling solution reported in this article yielded a very substantial 16.4 percent reduction in annual laboratory courier costs and a significant improvement in service levels. This study indicates that management science techniques and software are readily adaptable to the healthcare environment and are amenable to use by healthcare administrators.

  15. An Efficient Shared Adaptive Packet Loss Concealment Scheme through 1-Port Gateway System for Internet Telephony Service

    NASA Astrophysics Data System (ADS)

    Kim, Jinsul; Lee, Hyunwoo; Ryu, Won; Lee, Byungsun; Hahn, Minsoo

    In this letter, we propose a shared adaptive packet loss concealment scheme for the high quality guaranteed Internet telephony service which connects multiple users. In order to recover packet loss efficiently in the all-IP based convergence environment, we provide a robust signal recovery scheme which is based on the shared adaptive both-side information utilization. This scheme is provided according to the average magnitude variation across the frames and the pitch period replication on the 1-port gateway (G/W) system. The simulated performance demonstrates that the proposed scheme has the advantages of low processing times and high recovery rates in the all-IP based ubiquitous environment.

  16. Energy-efficient human body communication receiver chipset using wideband signaling scheme.

    PubMed

    Song, Seong-Jun; Cho, Namjun; Kim, Sunyoung; Yoo, Hoi-Jun

    2007-01-01

    This paper presents an energy-efficient wideband signaling receiver for communication channels using the human body as a data transmission medium. The wideband signaling scheme with the direct-coupled interface provides the energy-efficient transmission of multimedia data around the human body. The wideband signaling receiver incorporates with a receiver AFE exploiting wideband symmetric triggering technique and an all-digital CDR circuit with quadratic sampling technique. The AFE operates at 10-Mb/s data rate with input sensitivity of -27dBm and the operational bandwidth of 200-MHz. The CDR recovers clock and data of 2-Mb/s at a bit error rate of 10(-7). The receiver chipset consumes only 5-mW from a 1-V supply, thereby achieving the bit energy of 2.5-nJ/bit.

  17. Efficient Z-scheme charge separation in novel vertically aligned ZnO/CdSSe nanotrees

    NASA Astrophysics Data System (ADS)

    Li, Zhengxin; Nieto-Pescador, Jesus; Carson, Alexander J.; Blake, Jolie C.; Gundlach, Lars

    2016-04-01

    A new tree-like ZnO/CdSSe nanocomposite with CdSSe branches grown on ZnO nanowires prepared via a two-step chemical vapor deposition is presented. The nanotrees (NTs) are vertically aligned on a substrate. The CdSSe branches result in strong visible light absorption and form a type-II heterojunction with the ZnO stem that facilitates efficient electron transfer. A combination of photoluminescence spectroscopy and lifetime measurements indicates that the NTs are promising materials for applications that benefit from a Z-scheme charge transfer mechanism. Vertically aligned branched ZnO nanowires can provide direct electron transport pathways to substrates and allow for efficient charge separation. These advantages of nanoscale hierarchical heterostructures make ZnO/CdSSe NTs a promising semiconductor material for solar cells, and other opto-electronic devices.

  18. Low-loss and energy efficient modulation in silicon photonic waveguides by adiabatic elimination scheme

    NASA Astrophysics Data System (ADS)

    Mrejen, Michael; Suchowski, Haim; Bachelard, Nicolas; Wang, Yuan; Zhang, Xiang

    2017-07-01

    High-speed Silicon Photonics calls for solutions providing a small footprint, high density, and minimum crosstalk, as exemplified by the recent development of integrated optical modulators. Yet, the performances of such modulators are hindered by intrinsic material losses, which results in low energy efficiency. Using the concept of Adiabatic Elimination, here, we introduce a scheme allowing for the low-loss modulation in densely packed waveguides. Our system is composed of two waveguides, whose coupling is mediated by an intermediate third waveguide. The signal is carried by the two outer modes, while the active control of their coupling is achieved via the intermediate dark mode. The modulation is performed by the manipulation of the central-waveguide mode index, leaving the signal-carrying waveguides unaffected by the loss. We discuss how Adiabatic Elimination provides a solution for mitigating signal losses and designing relatively compact, broadband, and energy-efficient integrated optical modulators.

  19. Efficient postprocessing scheme for block-coded images based on multiscale edge detection

    NASA Astrophysics Data System (ADS)

    Wu, Shuanhu; Yan, Hong; Tan, Zheng

    2001-09-01

    The block discrete cosine transform (BDCT) is the most widely used technique for the compression of both still and moving images, a major problem related with the BDCT techniques is that the decoded images, especially at low bit rate, exhibit visually annoying blocking effects. In this paper, based on Mallets multiscale edge detection, we proposed an efficient deblocking algorithm to further improved the coding performance. The advantage of our algorithm is that it can efficiently preserve texture structure in the original decompressed images. Our method is similar to that of Z. Xiong's, where the Z.Xiong's method is not suitable for images with a large portion of texture; for instance, the Barbara Image. The difference of our method and the Z.Xiong's is that our method adopted a new thresholding scheme for multi-scale edge detection instead of exploiting cross-scale correlation for edge detection. Numerical experiment results show that our scheme not only outperforms Z.Xiong's for various images in the case of the same computational complexity, but also preserve texture structure in the decompressed images at the same time. Compared with the best iterative-based method (POCS) reported in the literature, our algorithm can achieve the same peak signal-to-noise ratio (PSNR) improvement and give visually very pleasing images as well.

  20. An efficient coding scheme for surveillance videos captured by stationary cameras

    NASA Astrophysics Data System (ADS)

    Zhang, Xianguo; Liang, Luhong; Huang, Qian; Liu, Yazhou; Huang, Tiejun; Gao, Wen

    2010-07-01

    In this paper, a new scheme is presented to improve the coding efficiency of sequences captured by stationary cameras (or namely, static cameras) for video surveillance applications. We introduce two novel kinds of frames (namely background frame and difference frame) for input frames to represent the foreground/background without object detection, tracking or segmentation. The background frame is built using a background modeling procedure and periodically updated while encoding. The difference frame is calculated using the input frame and the background frame. A sequence structure is proposed to generate high quality background frames and efficiently code difference frames without delay, and then surveillance videos can be easily compressed by encoding the background frames and difference frames in a traditional manner. In practice, the H.264/AVC encoder JM 16.0 is employed as a build-in coding module to encode those frames. Experimental results on eight in-door and out-door surveillance videos show that the proposed scheme achieves 0.12 dB~1.53 dB gain in PSNR over the JM 16.0 anchor specially configured for surveillance videos.

  1. Towards an ultra efficient kinetic scheme. Part I: Basics on the BGK equation

    NASA Astrophysics Data System (ADS)

    Dimarco, Giacomo; Loubere, Raphaël

    2013-12-01

    In this paper we present a new ultra efficient numerical method for solving kinetic equations. In this preliminary work, we present the scheme in the case of the BGK relaxation operator. The scheme, being based on a splitting technique between transport and collision, can be easily extended to other collisional operators as the Boltzmann collision integral or to other kinetic equations such as the Vlasov equation. The key idea, on which the method relies, is to solve the collision part on a grid and then to solve exactly the transport linear part by following the characteristics backward in time. The main difference between the method proposed and semi-Lagrangian methods is that here we do not need to reconstruct the distribution function at each time step. This allows to tremendously reduce the computational cost of the method and it permits for the first time, to the author's knowledge, to compute solutions of full six dimensional kinetic equations on a single processor laptop machine. Numerical examples, up to the full three dimensional case, are presented which validate the method and assess its efficiency in 1D, 2D and 3D.

  2. Robust and efficient biometrics based password authentication scheme for telecare medicine information systems using extended chaotic maps.

    PubMed

    Lu, Yanrong; Li, Lixiang; Peng, Haipeng; Xie, Dong; Yang, Yixian

    2015-06-01

    The Telecare Medicine Information Systems (TMISs) provide an efficient communicating platform supporting the patients access health-care delivery services via internet or mobile networks. Authentication becomes an essential need when a remote patient logins into the telecare server. Recently, many extended chaotic maps based authentication schemes using smart cards for TMISs have been proposed. Li et al. proposed a secure smart cards based authentication scheme for TMISs using extended chaotic maps based on Lee's and Jiang et al.'s scheme. In this study, we show that Li et al.'s scheme has still some weaknesses such as violation the session key security, vulnerability to user impersonation attack and lack of local verification. To conquer these flaws, we propose a chaotic maps and smart cards based password authentication scheme by applying biometrics technique and hash function operations. Through the informal and formal security analyses, we demonstrate that our scheme is resilient possible known attacks including the attacks found in Li et al.'s scheme. As compared with the previous authentication schemes, the proposed scheme is more secure and efficient and hence more practical for telemedical environments.

  3. An efficient chaotic maps-based authentication and key agreement scheme using smartcards for telecare medicine information systems.

    PubMed

    Lee, Tian-Fu

    2013-12-01

    A smartcard-based authentication and key agreement scheme for telecare medicine information systems enables patients, doctors, nurses and health visitors to use smartcards for secure login to medical information systems. Authorized users can then efficiently access remote services provided by the medicine information systems through public networks. Guo and Chang recently improved the efficiency of a smartcard authentication and key agreement scheme by using chaotic maps. Later, Hao et al. reported that the scheme developed by Guo and Chang had two weaknesses: inability to provide anonymity and inefficient double secrets. Therefore, Hao et al. proposed an authentication scheme for telecare medicine information systems that solved these weaknesses and improved performance. However, a limitation in both schemes is their violation of the contributory property of key agreements. This investigation discusses these weaknesses and proposes a new smartcard-based authentication and key agreement scheme that uses chaotic maps for telecare medicine information systems. Compared to conventional schemes, the proposed scheme provides fewer weaknesses, better security, and more efficiency.

  4. A new cooperative MIMO scheme based on SM for energy-efficiency improvement in wireless sensor network.

    PubMed

    Peng, Yuyang; Choi, Jaeho

    2014-01-01

    Improving the energy efficiency in wireless sensor networks (WSN) has attracted considerable attention nowadays. The multiple-input multiple-output (MIMO) technique has been proved as a good candidate for improving the energy efficiency, but it may not be feasible in WSN which is due to the size limitation of the sensor node. As a solution, the cooperative multiple-input multiple-output (CMIMO) technique overcomes this constraint and shows a dramatically good performance. In this paper, a new CMIMO scheme based on the spatial modulation (SM) technique named CMIMO-SM is proposed for energy-efficiency improvement. We first establish the system model of CMIMO-SM. Based on this model, the transmission approach is introduced graphically. In order to evaluate the performance of the proposed scheme, a detailed analysis in terms of energy consumption per bit of the proposed scheme compared with the conventional CMIMO is presented. Later, under the guide of this new scheme we extend our proposed CMIMO-SM to a multihop clustered WSN for further achieving energy efficiency by finding an optimal hop-length. Equidistant hop as the traditional scheme will be compared in this paper. Results from the simulations and numerical experiments indicate that by the use of the proposed scheme, significant savings in terms of total energy consumption can be achieved. Combining the proposed scheme with monitoring sensor node will provide a good performance in arbitrary deployed WSN such as forest fire detection system.

  5. A New Cooperative MIMO Scheme Based on SM for Energy-Efficiency Improvement in Wireless Sensor Network

    PubMed Central

    Peng, Yuyang; Choi, Jaeho

    2014-01-01

    Improving the energy efficiency in wireless sensor networks (WSN) has attracted considerable attention nowadays. The multiple-input multiple-output (MIMO) technique has been proved as a good candidate for improving the energy efficiency, but it may not be feasible in WSN which is due to the size limitation of the sensor node. As a solution, the cooperative multiple-input multiple-output (CMIMO) technique overcomes this constraint and shows a dramatically good performance. In this paper, a new CMIMO scheme based on the spatial modulation (SM) technique named CMIMO-SM is proposed for energy-efficiency improvement. We first establish the system model of CMIMO-SM. Based on this model, the transmission approach is introduced graphically. In order to evaluate the performance of the proposed scheme, a detailed analysis in terms of energy consumption per bit of the proposed scheme compared with the conventional CMIMO is presented. Later, under the guide of this new scheme we extend our proposed CMIMO-SM to a multihop clustered WSN for further achieving energy efficiency by finding an optimal hop-length. Equidistant hop as the traditional scheme will be compared in this paper. Results from the simulations and numerical experiments indicate that by the use of the proposed scheme, significant savings in terms of total energy consumption can be achieved. Combining the proposed scheme with monitoring sensor node will provide a good performance in arbitrary deployed WSN such as forest fire detection system. PMID:24707224

  6. An efficient sparse matrix multiplication scheme for the CYBER 205 computer

    NASA Technical Reports Server (NTRS)

    Lambiotte, Jules J., Jr.

    1988-01-01

    This paper describes the development of an efficient algorithm for computing the product of a matrix and vector on a CYBER 205 vector computer. The desire to provide software which allows the user to choose between the often conflicting goals of minimizing central processing unit (CPU) time or storage requirements has led to a diagonal-based algorithm in which one of four types of storage is selected for each diagonal. The candidate storage types employed were chosen to be efficient on the CYBER 205 for diagonals which have nonzero structure which is dense, moderately sparse, very sparse and short, or very sparse and long; however, for many densities, no diagonal type is most efficient with respect to both resource requirements, and a trade-off must be made. For each diagonal, an initialization subroutine estimates the CPU time and storage required for each storage type based on results from previously performed numerical experimentation. These requirements are adjusted by weights provided by the user which reflect the relative importance the user places on the two resources. The adjusted resource requirements are then compared to select the most efficient storage and computational scheme.

  7. Computational solutions of three-dimensional advection-diffusion equation using fourth order time efficient alternating direction implicit scheme

    NASA Astrophysics Data System (ADS)

    Saqib, Muhammad; Hasnain, Shahid; Mashat, Daoud Suleiman

    2017-08-01

    To develop an efficient numerical scheme for three-dimensional advection diffusion equation, higher order ADI method was proposed. 2nd and fourth order ADI schemes were used to handle such problem. Von Neumann stability analysis shows that Alternating Direction Implicit scheme is unconditionally stable. The accuracy and efficiency of such schemes was depicted by two test problems. Numerical results for two test problems were carried out to establish the performance of the given method and to compare it with the others Typical methods. Fourth order ADI method were found to be very efficient and stable for solving three dimensional Advection Diffusion Equation. The proposed methods can be implemented for solving non-linear problems arising in engineering and physics.

  8. Energy-Efficient Deadline-Aware Data-Gathering Scheme Using Multiple Mobile Data Collectors.

    PubMed

    Dasgupta, Rumpa; Yoon, Seokhoon

    2017-04-01

    In wireless sensor networks, the data collected by sensors are usually forwarded to the sink through multi-hop forwarding. However, multi-hop forwarding can be inefficient due to the energy hole problem and high communications overhead. Moreover, when the monitored area is large and the number of sensors is small, sensors cannot send the data via multi-hop forwarding due to the lack of network connectivity. In order to address those problems of multi-hop forwarding, in this paper, we consider a data collection scheme that uses mobile data collectors (MDCs), which visit sensors and collect data from them. Due to the recent breakthroughs in wireless power transfer technology, MDCs can also be used to recharge the sensors to keep them from draining their energy. In MDC-based data-gathering schemes, a big challenge is how to find the MDCs' traveling paths in a balanced way, such that their energy consumption is minimized and the packet-delay constraint is satisfied. Therefore, in this paper, we aim at finding the MDCs' paths, taking energy efficiency and delay constraints into account. We first define an optimization problem, named the delay-constrained energy minimization (DCEM) problem, to find the paths for MDCs. An integer linear programming problem is formulated to find the optimal solution. We also propose a two-phase path-selection algorithm to efficiently solve the DCEM problem. Simulations are performed to compare the performance of the proposed algorithms with two heuristics algorithms for the vehicle routing problem under various scenarios. The simulation results show that the proposed algorithms can outperform existing algorithms in terms of energy efficiency and packet delay.

  9. Energy-Efficient Deadline-Aware Data-Gathering Scheme Using Multiple Mobile Data Collectors

    PubMed Central

    Dasgupta, Rumpa; Yoon, Seokhoon

    2017-01-01

    In wireless sensor networks, the data collected by sensors are usually forwarded to the sink through multi-hop forwarding. However, multi-hop forwarding can be inefficient due to the energy hole problem and high communications overhead. Moreover, when the monitored area is large and the number of sensors is small, sensors cannot send the data via multi-hop forwarding due to the lack of network connectivity. In order to address those problems of multi-hop forwarding, in this paper, we consider a data collection scheme that uses mobile data collectors (MDCs), which visit sensors and collect data from them. Due to the recent breakthroughs in wireless power transfer technology, MDCs can also be used to recharge the sensors to keep them from draining their energy. In MDC-based data-gathering schemes, a big challenge is how to find the MDCs’ traveling paths in a balanced way, such that their energy consumption is minimized and the packet-delay constraint is satisfied. Therefore, in this paper, we aim at finding the MDCs’ paths, taking energy efficiency and delay constraints into account. We first define an optimization problem, named the delay-constrained energy minimization (DCEM) problem, to find the paths for MDCs. An integer linear programming problem is formulated to find the optimal solution. We also propose a two-phase path-selection algorithm to efficiently solve the DCEM problem. Simulations are performed to compare the performance of the proposed algorithms with two heuristics algorithms for the vehicle routing problem under various scenarios. The simulation results show that the proposed algorithms can outperform existing algorithms in terms of energy efficiency and packet delay. PMID:28368300

  10. Implementation of a compressive sampling scheme for wireless sensors to achieve energy efficiency in a structural health monitoring system

    NASA Astrophysics Data System (ADS)

    O'Connor, Sean M.; Lynch, Jerome P.; Gilbert, Anna C.

    2013-04-01

    Wireless sensors have emerged to offer low-cost sensors with impressive functionality (e.g., data acquisition, computing, and communication) and modular installations. Such advantages enable higher nodal densities than tethered systems resulting in increased spatial resolution of the monitoring system. However, high nodal density comes at a cost as huge amounts of data are generated, weighing heavy on power sources, transmission bandwidth, and data management requirements, often making data compression necessary. The traditional compression paradigm consists of high rate (>Nyquist) uniform sampling and storage of the entire target signal followed by some desired compression scheme prior to transmission. The recently proposed compressed sensing (CS) framework combines the acquisition and compression stage together, thus removing the need for storage and operation of the full target signal prior to transmission. The effectiveness of the CS approach hinges on the presence of a sparse representation of the target signal in a known basis, similarly exploited by several traditional compressive sensing applications today (e.g., imaging, MRI). Field implementations of CS schemes in wireless SHM systems have been challenging due to the lack of commercially available sensing units capable of sampling methods (e.g., random) consistent with the compressed sensing framework, often moving evaluation of CS techniques to simulation and post-processing. The research presented here describes implementation of a CS sampling scheme to the Narada wireless sensing node and the energy efficiencies observed in the deployed sensors. Of interest in this study is the compressibility of acceleration response signals collected from a multi-girder steel-concrete composite bridge. The study shows the benefit of CS in reducing data requirements while ensuring data analysis on compressed data remain accurate.

  11. Efficiently sphere-decodable physical layer transmission schemes for wireless storage networks

    NASA Astrophysics Data System (ADS)

    Lu, Hsiao-Feng Francis; Barreal, Amaro; Karpuk, David; Hollanti, Camilla

    2016-12-01

    Three transmission schemes over a new type of multiple-access channel (MAC) model with inter-source communication links are proposed and investigated in this paper. This new channel model is well motivated by, e.g., wireless distributed storage networks, where communication to repair a lost node takes place from helper nodes to a repairing node over a wireless channel. Since in many wireless networks nodes can come and go in an arbitrary manner, there must be an inherent capability of inter-node communication between every pair of nodes. Assuming that communication is possible between every pair of helper nodes, the newly proposed schemes are based on various smart time-sharing and relaying strategies. In other words, certain helper nodes will be regarded as relays, thereby converting the conventional uncooperative multiple-access channel to a multiple-access relay channel (MARC). The diversity-multiplexing gain tradeoff (DMT) of the system together with efficient sphere-decodability and low structural complexity in terms of the number of antennas required at each end is used as the main design objectives. While the optimal DMT for the new channel model is fully open, it is shown that the proposed schemes outperform the DMT of the simple time-sharing protocol and, in some cases, even the optimal uncooperative MAC DMT. While using a wireless distributed storage network as a motivating example throughout the paper, the MAC transmission techniques proposed here are completely general and as such applicable to any MAC communication with inter-source communication links.

  12. MODEL OF PHYTOPLANKTON COMPETITION FOR LIMITING AND NONLIMITING NUTRIENTS: IMPLICATIONS FOR DEVELOPMENT OF ESTUARINE AND NEARSHORE MANAGEMENT SCHEMES

    EPA Science Inventory

    The global increase of noxious bloom occurrences has increased the need for phytoplankton management schemes. Such schemes require the ability to predict phytoplankton succession. Equilibrium Resources Competition theory, which is popular for predicting succession in lake systems...

  13. MODEL OF PHYTOPLANKTON COMPETITION FOR LIMITING AND NONLIMITING NUTRIENTS: IMPLICATIONS FOR DEVELOPMENT OF ESTUARINE AND NEARSHORE MANAGEMENT SCHEMES

    EPA Science Inventory

    The global increase of noxious bloom occurrences has increased the need for phytoplankton management schemes. Such schemes require the ability to predict phytoplankton succession. Equilibrium Resources Competition theory, which is popular for predicting succession in lake systems...

  14. A Lightweight Encryption Scheme Combined with Trust Management for Privacy-Preserving in Body Sensor Networks.

    PubMed

    Guo, Ping; Wang, Jin; Ji, Sai; Geng, Xue Hua; Xiong, Neal N

    2015-12-01

    With the pervasiveness of smart phones and the advance of wireless body sensor network (BSN), mobile Healthcare (m-Healthcare), which extends the operation of Healthcare provider into a pervasive environment for better health monitoring, has attracted considerable interest recently. However, the flourish of m-Healthcare still faces many challenges including information security and privacy preservation. In this paper, we propose a secure and privacy-preserving framework combining with multilevel trust management. In our scheme, smart phone resources including computing power and energy can be opportunistically gathered to process the computing-intensive PHI (personal health information) during m-Healthcare emergency with minimal privacy disclosure. In specific, to leverage the PHI privacy disclosure and the high reliability of PHI process and transmission in m-Healthcare emergency, we introduce an efficient lightweight encryption for those users whose trust level is low, which is based on mix cipher algorithms and pair of plain text and cipher texts, and allow a medical user to decide who can participate in the opportunistic computing to assist in processing his overwhelming PHI data. Detailed security analysis and simulations show that the proposed framework can efficiently achieve user-centric privacy protection in m-Healthcare system.

  15. Efficient field-free orientation of CO molecules using a three-step excitation scheme

    NASA Astrophysics Data System (ADS)

    Huang, Yin; Xie, Ting; Wang, Gao-Ren; Han, Yong-Chang; Cong, Shu-Lin

    2013-11-01

    An efficient three-step excitation scheme is proposed to achieve the strong molecular orientation. By taking the CO molecule for example, via the Raman excitation by the femtosecond pulse L 1 and subsequently resonant excitations by a single-cycle THz pulse L 2, the high degree of the field-free orientation of |⟨ cos θ ⟩ |max = 0.8921 can be obtained at the rotational temperature T = 0 K. An additional single-cycle THz pulse L 3 is introduced to further regulate the population distribution on rotational states and decrease the reduction of the orientation originating from the offset phase. With the increase of the central frequency ω 3 of L 3, the optimal |⟨ cos θ ⟩ |max increases monotonically. When ω 3 = 1.0 THz, the degree of the field-free orientation reaches |⟨ cos θ ⟩ |max = 0.9401. Moreover, our scheme is robust against the rotational temperature. Although the molecular orientation weakens with the rise of rotational temperature, |⟨ ⟨ cos θ ⟩ ⟩ | > 0.5 is still obtained until T = 22.8 K.

  16. Australian managed entry scheme: a new manageable process for the reimbursement of new medicines?

    PubMed

    Wonder, Michael; Backhouse, Martin E; Sullivan, Sean D

    2012-05-01

    The global prescription medicines industry argues that it needs high prices for new medicines to meet ever-increasing development costs. While many payers are prepared to pay high prices if they represent good value for money, they first need to feel assured that the value for money estimates are robust. Insofar as new medicines enter the market with limited and uncertain data relating to their performance in normal clinical practice, the value for money case for some medicines may well be driven largely by assumptions than by empirical evidence. The concern to manufacturers is that payers respond to this uncertainty by listing the product at a lower price (which may not satisfy the producer) or not listing the product until more evidence is available (which may not satisfy clinicians and patients). Is there a solution that will satisfy all key stakeholders? Will clinicians and patients continue to have timely access to new medicines and will payers have sustainable reimbursement systems? Will the industry continue to be rewarded with high prices for new medicines so long as they represent good value for money? In 2011, the Australian Government introduced a managed entry scheme whereby the Pharmaceutical Benefits Advisory Committee will recommend the listing of a new medicine at a price justified by the existing evidence, pending the availability of more conclusive evidence of cost-effectiveness to support its continued listing at a higher price. This commentary examines the Australian Government's managed entry scheme and issues that are likely to arise from its implementation. Copyright © 2012 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  17. Scenario Tools For Efficient Eutrophication Management

    NASA Astrophysics Data System (ADS)

    Arheimer, B.; Vastra SP3 Team

    Several possible measures are available to reduce diffuse (non-point source) nutri- ent load to surface water and thereby reduce eutrophication. Such measures include changed arable practices and constructions of wetlands and buffer zones in the land- scape, as well as managing lake ecosystems. In some cases, such as for wetlands, there is an intense debate regarding the efficiency of their nutrient reducing capability. In ad- dition, the combined effect of several measures in a catchment is not necessarily equal to their sum. It is therefore important to apply a holistic and integrated catchment approach when applying and evaluating different management strategies. To facili- tate such catchment analyses, the Swedish water management research programme (VASTRA) develop modelling tools addressing both phosphorus (P) and nitrogen (N) dynamics in catchments. During the last three years decision support tools for N man- agement in rivers and lakes have been developed (e.g., HBV-N, BIOLA) and applied in scenarios to demonstrate the effect of various reducing measures. At present, similar tools for P are under development. This presentation will demonstrate the VASTRA tool-box and its applications for efficient eutrophication management.

  18. An efficient approximate factorization implicit scheme for the equations of gasdynamics

    NASA Technical Reports Server (NTRS)

    Barth, T. J.; Steger, J. L.

    1984-01-01

    An efficient implicit finite-difference algorithm for the gas dynamic equations utilizing matrix reduction techniques is presented. A significant reduction in arithmetic operations is achieved while maintaining the same favorable stability characteristics and generality found in the Beam and Warming approximate factorization algorithm. Steady-state solutions to the conservative Euler equations in generalized coordinates are obtained for transonic flows about a NACA 0012 airfoil. The theoretical extension of the matrix reduction technique to the full Navier-Stokes equations in Cartesian coordinates is presented in detail. Linear stability, using a Fourier stability analysis, is demonstrated and discussed for the one-dimensional Euler equations. It is shown that the method offers advantages over the conventional Beam and Warming scheme and can retrofit existing Beam and Warming codes with minimal effort.

  19. An Efficient Acquisition Scheme for a High Sensitivity Assisted GPS Receiver

    NASA Astrophysics Data System (ADS)

    Liu, Zhixing; Fan, Chunming; Asano, Shoichiro; Kishimoto, Nobuhiro; Hojo, Harumasa; Yasuda, Akio

    Automatic location identification is required for emergency calls in Japan and many other countries. However, promptly providing a reliable position is a problem in places where the global positioning system (GPS) signal is extremely weak. We propose an acquisition scheme for the assisted GPS (AGPS) architecture based on a timing-synchronized mobile network. System errors as well as code uncertainty range and frequency uncertainty range are discussed. With this method, the acquisition search range is significantly reduced, and a long-time coherent correlation is made possible. Simulations and experiments prove that the method is fast, efficient and power-saving for the user handset. Furthermore, the AGPS receiver can perform a short TTFF (Time To First Fix) start even with no ephemeris kept in the handset.

  20. Numerical simulations of non-equilibrium shock layers with efficient implicit schemes

    NASA Technical Reports Server (NTRS)

    Cambier, Jean-Luc; Prabhu, Dinesh K.

    1992-01-01

    Current and future calculations of nonequilibrium shock layers require the use of a very large number of equations, due to a multiplicity of chemical species, excited states, and internal energy modes. The computational cost associated with the use of standard implicit methods becomes prohibitive; it is therefore desirable to examine the potential of several methods and determine if any can be projected to be more efficient and accurate for large systems of equations. Here, the performance of several implicit schemes on several simple practical examples of reacting flows is examined. The Euler equations are solved by three different implicit methods, and two methods of coupling between the fluid dynamics and the chemistry are studied. Several cases of stiffness are considered and both 1D and 2D examples are computed.

  1. An efficient state-specific scheme of time-dependent density functional theory

    NASA Astrophysics Data System (ADS)

    Chiba, Mahito; Tsuneda, Takao; Hirao, Kimihiko

    2006-03-01

    A state-specific scheme for time-dependent density functional theory (SS-TDDFT) based on the Davidson algorithm is presented. SS-TDDFT is a method devised for speeding up TDDFT calculations by screening transitions that contribute to a specific excitation. By applying this method to calculations of the low-lying excitation energies of test molecules (N 2, CO, H 2CO, C 2H 4 and C 6H 6), water clusters and polyenes, we found that SS-TDDFT accurately reproduced the excitation energies of standard TDDFT while drastically reducing the rank of the TDDFT response matrix without loss of accuracy. We have thus formulated TDDFT that works more efficiently and economically for memory storage.

  2. Efficient congestion control scheme for providing QoS to I-VPN

    NASA Astrophysics Data System (ADS)

    De Marco, Martino; Trabucchi, Sara

    1998-12-01

    In this paper we outline an overall network architecture for the Internet Service Providers who want offer an Internet- Virtual Private Network service with QoS guarantees and, at the same time, with a high-level of efficiency in the network resource usage. The proposed approach is based on the negotiation of a service level agreement, which includes the definition of profile of traffic the user is allowed to emit. The ingress nodes perform an adaptive shaping of the user traffic entering the network, driven by a fast congestion notification scheme. In this scenario, the adoption of a service architecture based on a class-of- service concept enables the Internet Service Provider to offer different level of network performance according to the customer needs.

  3. Modeling and performance analysis of an improved movement-based location management scheme for packet-switched mobile communication systems.

    PubMed

    Chung, Yun Won; Kwon, Jae Kyun; Park, Suwon

    2014-01-01

    One of the key technologies to support mobility of mobile station (MS) in mobile communication systems is location management which consists of location update and paging. In this paper, an improved movement-based location management scheme with two movement thresholds is proposed, considering bursty data traffic characteristics of packet-switched (PS) services. The analytical modeling for location update and paging signaling loads of the proposed scheme is developed thoroughly and the performance of the proposed scheme is compared with that of the conventional scheme. We show that the proposed scheme outperforms the conventional scheme in terms of total signaling load with an appropriate selection of movement thresholds.

  4. Smart Salinity Management in Low-lying Deltaic Areas: A Model Predictive Control Scheme Applied to a Test Canal

    NASA Astrophysics Data System (ADS)

    Ekin Aydin, Boran; Rutten, Martine; Oude Essink, Gualbert H. P.; Delsman, Joost; Abraham, Edo

    2017-04-01

    Saline groundwater exfiltration to surface water increases surface water salinization and degrades the water quality in low-lying deltaic areas. As the use of surface water is less appropriate for agricultural, industrial and drinking water production due to salinization, freshwater diverted from a river is often utilised for flushing canals and ditches in these areas. Current water management strategies for flushing control in low-lying deltaic areas have to be revised to mitigate expected negative effects of climate change, sea level increase and decreasing fresh water availability. Model predictive control (MPC) is a powerful control method that is increasingly used for managing water systems. The explicit consideration of constraints and multi-objective management are important features of MPC. In this study, an MPC scheme is developed and tested for combined salinity and water level control of a ditch/water course. Saline groundwater exfiltration fluxes and salinities are modelled by applying the Rapid Saline Groundwater Exfiltration Model (RSGEM) and used as known disturbances for the MPC scheme. The developed control scheme is applied to a test canal using real data from a Dutch polder (Polders are low lying and artificially drained areas surrounded by dikes, with a controlled surface water level below M.S.L) which is affected by high saline groundwater exfiltration. This test demonstrates the performance of the controller for a real scenario. Simulation results show that MPC can increase the operational efficiency of flushing operations.

  5. A mass conserving and multi-tracer efficient transport scheme in the online integrated Enviro-HIRLAM model

    NASA Astrophysics Data System (ADS)

    Sørensen, B.; Kaas, E.; Korsholm, U. S.

    2012-11-01

    In this paper a new advection scheme for the online coupled chemical-weather prediction model Enviro-HIRLAM is presented. The new scheme is based on the locally mass conserving semi-Lagrangian method (LMCSL), where the original two-dimensional scheme has been extended to a fully three-dimensional version. This means that the three-dimensional semi-implicit semi-Lagrangian scheme which is currently used in Enviro-HIRLAM, is largely unchanged. The HIRLAM model is a computationally efficient hydrostatic operational short term numerical weather prediction model, which is used as the base for the online integrated Enviro-HIRLAM. The new scheme is shown to be efficient, mass conserving, and shape-preserving while only requiring minor alterations to the original code. It still retains the stability at long time steps, which the semi-Lagrangian schemes are known for, while handling the emissions of chemical species accurately. Several mass conserving filters have been tested to assess the optimal balance of accuracy vs. efficiency.

  6. A mass-conserving and multi-tracer efficient transport scheme in the online integrated Enviro-HIRLAM model

    NASA Astrophysics Data System (ADS)

    Sørensen, B.; Kaas, E.; Korsholm, U. S.

    2013-07-01

    In this paper a new advection scheme for the online coupled chemical-weather prediction model Enviro-HIRLAM is presented. The new scheme is based on the locally mass-conserving semi-Lagrangian method (LMCSL), where the original two-dimensional scheme has been extended to a fully three-dimensional version. This means that the three-dimensional semi-implicit semi-Lagrangian scheme which is currently used in Enviro-HIRLAM is largely unchanged. The HIRLAM model is a computationally efficient hydrostatic operational short-term numerical weather prediction model, which is used as the base for the online integrated Enviro-HIRLAM. The new scheme is shown to be efficient, mass conserving, and shape preserving, while only requiring minor alterations to the original code. It still retains the stability at long time steps, which the semi-Lagrangian schemes are known for, while handling the emissions of chemical species accurately. Several mass-conserving filters have been tested to assess the optimal balance of accuracy vs. efficiency.

  7. An Improvement of Robust and Efficient Biometrics Based Password Authentication Scheme for Telecare Medicine Information Systems Using Extended Chaotic Maps.

    PubMed

    Moon, Jongho; Choi, Younsung; Kim, Jiye; Won, Dongho

    2016-03-01

    Recently, numerous extended chaotic map-based password authentication schemes that employ smart card technology were proposed for Telecare Medical Information Systems (TMISs). In 2015, Lu et al. used Li et al.'s scheme as a basis to propose a password authentication scheme for TMISs that is based on biometrics and smart card technology and employs extended chaotic maps. Lu et al. demonstrated that Li et al.'s scheme comprises some weaknesses such as those regarding a violation of the session-key security, a vulnerability to the user impersonation attack, and a lack of local verification. In this paper, however, we show that Lu et al.'s scheme is still insecure with respect to issues such as a violation of the session-key security, and that it is vulnerable to both the outsider attack and the impersonation attack. To overcome these drawbacks, we retain the useful properties of Lu et al.'s scheme to propose a new password authentication scheme that is based on smart card technology and requires the use of chaotic maps. Then, we show that our proposed scheme is more secure and efficient and supports security properties.

  8. An efficient parallel implementation of explicit multirate Runge–Kutta schemes for discontinuous Galerkin computations

    SciTech Connect

    Seny, Bruno Lambrechts, Jonathan; Toulorge, Thomas; Legat, Vincent; Remacle, Jean-François

    2014-01-01

    Although explicit time integration schemes require small computational efforts per time step, their efficiency is severely restricted by their stability limits. Indeed, the multi-scale nature of some physical processes combined with highly unstructured meshes can lead some elements to impose a severely small stable time step for a global problem. Multirate methods offer a way to increase the global efficiency by gathering grid cells in appropriate groups under local stability conditions. These methods are well suited to the discontinuous Galerkin framework. The parallelization of the multirate strategy is challenging because grid cells have different workloads. The computational cost is different for each sub-time step depending on the elements involved and a classical partitioning strategy is not adequate any more. In this paper, we propose a solution that makes use of multi-constraint mesh partitioning. It tends to minimize the inter-processor communications, while ensuring that the workload is almost equally shared by every computer core at every stage of the algorithm. Particular attention is given to the simplicity of the parallel multirate algorithm while minimizing computational and communication overheads. Our implementation makes use of the MeTiS library for mesh partitioning and the Message Passing Interface for inter-processor communication. Performance analyses for two and three-dimensional practical applications confirm that multirate methods preserve important computational advantages of explicit methods up to a significant number of processors.

  9. Efficient and Security Enhanced Anonymous Authentication with Key Agreement Scheme in Wireless Sensor Networks.

    PubMed

    Jung, Jaewook; Moon, Jongho; Lee, Donghoon; Won, Dongho

    2017-03-21

    At present, users can utilize an authenticated key agreement protocol in a Wireless Sensor Network (WSN) to securely obtain desired information, and numerous studies have investigated authentication techniques to construct efficient, robust WSNs. Chang et al. recently presented an authenticated key agreement mechanism for WSNs and claimed that their authentication mechanism can both prevent various types of attacks, as well as preserve security properties. However, we have discovered that Chang et al's method possesses some security weaknesses. First, their mechanism cannot guarantee protection against a password guessing attack, user impersonation attack or session key compromise. Second, the mechanism results in a high load on the gateway node because the gateway node should always maintain the verifier tables. Third, there is no session key verification process in the authentication phase. To this end, we describe how the previously-stated weaknesses occur and propose a security-enhanced version for WSNs. We present a detailed analysis of the security and performance of our authenticated key agreement mechanism, which not only enhances security compared to that of related schemes, but also takes efficiency into consideration.

  10. Frame Transmission Efficiency-Based Cross-Layer Congestion Notification Scheme in Wireless Ad Hoc Networks

    PubMed Central

    He, Huaguang; Li, Taoshen; Feng, Luting; Ye, Jin

    2017-01-01

    Different from the traditional wired network, the fundamental cause of transmission congestion in wireless ad hoc networks is medium contention. How to utilize the congestion state from the MAC (Media Access Control) layer to adjust the transmission rate is core work for transport protocol design. However, recent works have shown that the existing cross-layer congestion detection solutions are too complex to be deployed or not able to characterize the congestion accurately. We first propose a new congestion metric called frame transmission efficiency (i.e., the ratio of successful transmission delay to the frame service delay), which describes the medium contention in a fast and accurate manner. We further present the design and implementation of RECN (ECN and the ratio of successful transmission delay to the frame service delay in the MAC layer, namely, the frame transmission efficiency), a general supporting scheme that adjusts the transport sending rate through a standard ECN (Explicit Congestion Notification) signaling method. Our method can be deployed on commodity switches with small firmware updates, while making no modification on end hosts. We integrate RECN transparently (i.e., without modification) with TCP on NS2 simulation. The experimental results show that RECN remarkably improves network goodput across multiple concurrent TCP flows. PMID:28714898

  11. Frame Transmission Efficiency-Based Cross-Layer Congestion Notification Scheme in Wireless Ad Hoc Networks.

    PubMed

    He, Huaguang; Li, Taoshen; Feng, Luting; Ye, Jin

    2017-07-15

    Different from the traditional wired network, the fundamental cause of transmission congestion in wireless ad hoc networks is medium contention. How to utilize the congestion state from the MAC (Media Access Control) layer to adjust the transmission rate is core work for transport protocol design. However, recent works have shown that the existing cross-layer congestion detection solutions are too complex to be deployed or not able to characterize the congestion accurately. We first propose a new congestion metric called frame transmission efficiency (i.e., the ratio of successful transmission delay to the frame service delay), which describes the medium contention in a fast and accurate manner. We further present the design and implementation of RECN (ECN and the ratio of successful transmission delay to the frame service delay in the MAC layer, namely, the frame transmission efficiency), a general supporting scheme that adjusts the transport sending rate through a standard ECN (Explicit Congestion Notification) signaling method. Our method can be deployed on commodity switches with small firmware updates, while making no modification on end hosts. We integrate RECN transparently (i.e., without modification) with TCP on NS2 simulation. The experimental results show that RECN remarkably improves network goodput across multiple concurrent TCP flows.

  12. Efficient and Security Enhanced Anonymous Authentication with Key Agreement Scheme in Wireless Sensor Networks

    PubMed Central

    Jung, Jaewook; Moon, Jongho; Lee, Donghoon; Won, Dongho

    2017-01-01

    At present, users can utilize an authenticated key agreement protocol in a Wireless Sensor Network (WSN) to securely obtain desired information, and numerous studies have investigated authentication techniques to construct efficient, robust WSNs. Chang et al. recently presented an authenticated key agreement mechanism for WSNs and claimed that their authentication mechanism can both prevent various types of attacks, as well as preserve security properties. However, we have discovered that Chang et al’s method possesses some security weaknesses. First, their mechanism cannot guarantee protection against a password guessing attack, user impersonation attack or session key compromise. Second, the mechanism results in a high load on the gateway node because the gateway node should always maintain the verifier tables. Third, there is no session key verification process in the authentication phase. To this end, we describe how the previously-stated weaknesses occur and propose a security-enhanced version for WSNs. We present a detailed analysis of the security and performance of our authenticated key agreement mechanism, which not only enhances security compared to that of related schemes, but also takes efficiency into consideration. PMID:28335572

  13. Efficient real gas Navier-Stokes computations of high speed flows using an LU scheme

    NASA Technical Reports Server (NTRS)

    Coirier, William J.

    1990-01-01

    An efficient method to account for the chemically frozen thermodynamic and transport properties of air in three dimensional Navier-Stokes calculations was demonstrated. This approach uses an explicitly specified equation of state (EOS) so that the fluid pressure, temperature and transport properties are directly related to the flow variables. Since the pressure is explicitly known as a general function of the flow variables no assumptions are made regarding the pressure derivatives in the construction of the flux Jacobians. The method is efficient since no sub-iterations are required to deduce the pressure and temperature from the flux variables and allows different equations of state to be easily supplied to the code. The flexibility of the EOS approach is demonstrated by implementing a high order TVD upwinding scheme based upon flux differencing and Van Leer's flux vector splitting. The EOS approach is demonstrated by computing the hypersonic flow through the corner region of two mutually perpendicular flat plates and through a simplified model of a scramjet module gap-seal configuration.

  14. An approach for quantifying the efficacy of ecological classification schemes as management tools

    NASA Astrophysics Data System (ADS)

    Flanagan, A. M.; Cerrato, R. M.

    2015-10-01

    Rigorous assessments of ecological classification schemes being applied to submerged environments are needed to evaluate their utility as management tools. Verification that a scheme can quantitatively capture habitat and community variation would be of considerable value to individuals responsible for making difficult management decisions relevant to widespread environmental challenges including those in fisheries, preservation or restoration of critical habitats, and climate change. In this paper, an assessment approach that evaluates a scheme by treating it like a quantitative statistical model is presented. It couples two direct gradient, multivariate statistical techniques, multivariate regression trees (MRT) and redundancy analysis (RDA), with a modelling protocol involving model formulation, model selection, parameter estimation, and measurement of precision to produce a very flexible strategy for analyzing structure in ecological data. To illustrate the proposed approach, the assessment focused on benthic infauna and evaluating the Folk grain size classification scheme, along with some alternative grain size models. Analysis of data sets revealed that while it was fairly easy to uncover biotic-environmental relationships that were over-fitted, the community structure inherent in the data tended to be robustly discernible and preserved across all grain size models, but rigidly parameterized models (i.e., a one size fits all approach for grain size characterization with fixed boundaries) were generally ineffective. The proposed approach provided a clear, detailed, and rigorous assessment of Folk and several alternative models and can be used for the quantitative evaluation of existing ecological classification schemes and/or in the development of new schemes.

  15. Comparison of medicines management strategies in insurance schemes in middle-income countries: four case studies.

    PubMed

    Kaplan, Warren A; Ashigbie, Paul G; Brooks, Mohamad I; Wirtz, Veronika J

    2017-01-01

    Many middle-income countries are scaling up health insurance schemes to provide financial protection and access to affordable medicines to poor and uninsured populations. Although there is a wealth of evidence on how high income countries with mature insurance schemes manage cost-effective use of medicines, there is limited evidence on the strategies used in middle-income countries. This paper compares the medicines management strategies that four insurance schemes in middle-income countries use to improve access and cost-effective use of medicines among beneficiaries. We compare key strategies promoting cost-effective medicines use in the New Rural Cooperative Medical Scheme (NCMS) in China, National Health Insurance Scheme in Ghana, Jamkesmas in Indonesia and Seguro Popular in Mexico. Through the peer-reviewed and grey literature as of late 2013, we identified strategies that met our inclusion criteria as well as any evidence showing if, and/or how, these strategies affected medicines management. Stakeholders involved and affected by medicines coverage policies in these insurance schemes were asked to provide relevant documents describing the medicines related aspects of these insurance programs. We also asked them specifically to identify publications discussing the unintended consequences of the strategies implemented. Use of formularies, bulk procurement, standard treatment guidelines and separation of prescribing and dispensing were present in all four schemes. Also, increased transparency through publication of tender agreements and procurement prices was introduced in all four. Common strategies shared by three out of four schemes were medicine price negotiation or rebates, generic reference pricing, fixed salaries for prescribers, accredited preferred provider network, disease management programs, and monitoring of medicines purchases. Cost-sharing and payment for performance was rarely used. There was a lack of performance monitoring strategies in all

  16. Efficient systematic scheme to construct second-principles lattice dynamical models

    NASA Astrophysics Data System (ADS)

    Escorihuela-Sayalero, Carlos; Wojdeł, Jacek C.; Íñiguez, Jorge

    2017-03-01

    We start from the polynomial interatomic potentials introduced by Wojdeł et al. [J. Phys.: Condens. Matter 25, 305401 (2013), 10.1088/0953-8984/25/30/305401] and take advantage of one of their key features—namely, the linear dependence of the energy on the potential's adjustable parameters—to devise a scheme for the construction of first-principles-based (second-principles) models for large-scale lattice-dynamical simulations. Our method presents the following convenient features. The parameters of the model are computed in a very fast and efficient way, as it is possible to recast the fit to a training set of first-principles data into a simple matrix diagonalization problem. Our method selects automatically the interactions that are most relevant to reproduce the training-set data, by choosing from a pool that includes virtually all possible coupling terms, and produces a family of models of increasing complexity and accuracy. We work with practical and convenient cross-validation criteria linked to the physical properties that will be relevant in future simulations based on the new model, and which greatly facilitate the task of identifying a potential that is simultaneously simple (thus computationally light), very accurate, and predictive. We also discuss practical ways to guarantee that our energy models are bounded from below, with a minimal impact on their accuracy. Finally, we demonstrate our scheme with an application to ferroelastic perovskite SrTiO3, which features many nontrivial lattice-dynamical features (e.g., a phase transition driven by soft phonons, competing structural instabilities, highly anharmonic dynamics) and provides a very demanding test.

  17. PHACK: An Efficient Scheme for Selective Forwarding Attack Detection in WSNs

    PubMed Central

    Liu, Anfeng; Dong, Mianxiong; Ota, Kaoru; Long, Jun

    2015-01-01

    In this paper, a Per-Hop Acknowledgement (PHACK)-based scheme is proposed for each packet transmission to detect selective forwarding attacks. In our scheme, the sink and each node along the forwarding path generate an acknowledgement (ACK) message for each received packet to confirm the normal packet transmission. The scheme, in which each ACK is returned to the source node along a different routing path, can significantly increase the resilience against attacks because it prevents an attacker from compromising nodes in the return routing path, which can otherwise interrupt the return of nodes’ ACK packets. For this case, the PHACK scheme also has better potential to detect abnormal packet loss and identify suspect nodes as well as better resilience against attacks. Another pivotal issue is the network lifetime of the PHACK scheme, as it generates more acknowledgements than previous ACK-based schemes. We demonstrate that the network lifetime of the PHACK scheme is not lower than that of other ACK-based schemes because the scheme just increases the energy consumption in non-hotspot areas and does not increase the energy consumption in hotspot areas. Moreover, the PHACK scheme greatly simplifies the protocol and is easy to implement. Both theoretical and simulation results are given to demonstrate the effectiveness of the proposed scheme in terms of high detection probability and the ability to identify suspect nodes. PMID:26690178

  18. Coping Intelligence: Efficient Life Stress Management

    PubMed Central

    Libin, Elena

    2017-01-01

    Coping Intelligence is defined as efficient individual ways of managing life stress. This paper presents a new assessment instrument named Coping IQ (CIQ; Coping Intelligence Questionnaire). A measure is based on the Multidimensional Positive Coping Model, which includes three cross-cutting parameters that characterize coping strategy as efficient or inefficient, emotional, cognitive or behavioral, and active or passive. Results of the factor analysis verified a basic two-factor structure of the Coping Intelligence with the alternative solutions for efficient and inefficient coping strategies characterized via three basic modalities. The validity of the Coping IQ instrument showed an internal consistency ranging from 0.72 to 0.81. The unified methodology that underlies the new concept of Coping Intelligence, as well as Coping IQ assessment, is applicable for studying both clinical and general populations. CIQ parameters might serve as useful feedback while assessing changes in individual coping repertoire, for CIQ measures strategies that can be modified as a result of life experiences or educational training. Based on the study findings, Coping Intelligence is further defined by a broad repertoire of life skills required to solve successfully everyday stress and life adversities in order to achieve desired goals and maintain physical, mental, and social well-being. PMID:28316579

  19. An Efficient User Authentication and User Anonymity Scheme with Provably Security for IoT-Based Medical Care System.

    PubMed

    Li, Chun-Ta; Wu, Tsu-Yang; Chen, Chin-Ling; Lee, Cheng-Chi; Chen, Chien-Ming

    2017-06-23

    In recent years, with the increase in degenerative diseases and the aging population in advanced countries, demands for medical care of older or solitary people have increased continually in hospitals and healthcare institutions. Applying wireless sensor networks for the IoT-based telemedicine system enables doctors, caregivers or families to monitor patients' physiological conditions at anytime and anyplace according to the acquired information. However, transmitting physiological data through the Internet concerns the personal privacy of patients. Therefore, before users can access medical care services in IoT-based medical care system, they must be authenticated. Typically, user authentication and data encryption are most critical for securing network communications over a public channel between two or more participants. In 2016, Liu and Chung proposed a bilinear pairing-based password authentication scheme for wireless healthcare sensor networks. They claimed their authentication scheme cannot only secure sensor data transmission, but also resist various well-known security attacks. In this paper, we demonstrate that Liu-Chung's scheme has some security weaknesses, and we further present an improved secure authentication and data encryption scheme for the IoT-based medical care system, which can provide user anonymity and prevent the security threats of replay and password/sensed data disclosure attacks. Moreover, we modify the authentication process to reduce redundancy in protocol design, and the proposed scheme is more efficient in performance compared with previous related schemes. Finally, the proposed scheme is provably secure in the random oracle model under ECDHP.

  20. An Efficient User Authentication and User Anonymity Scheme with Provably Security for IoT-Based Medical Care System

    PubMed Central

    Wu, Tsu-Yang; Chen, Chin-Ling; Lee, Cheng-Chi; Chen, Chien-Ming

    2017-01-01

    In recent years, with the increase in degenerative diseases and the aging population in advanced countries, demands for medical care of older or solitary people have increased continually in hospitals and healthcare institutions. Applying wireless sensor networks for the IoT-based telemedicine system enables doctors, caregivers or families to monitor patients’ physiological conditions at anytime and anyplace according to the acquired information. However, transmitting physiological data through the Internet concerns the personal privacy of patients. Therefore, before users can access medical care services in IoT-based medical care system, they must be authenticated. Typically, user authentication and data encryption are most critical for securing network communications over a public channel between two or more participants. In 2016, Liu and Chung proposed a bilinear pairing-based password authentication scheme for wireless healthcare sensor networks. They claimed their authentication scheme cannot only secure sensor data transmission, but also resist various well-known security attacks. In this paper, we demonstrate that Liu–Chung’s scheme has some security weaknesses, and we further present an improved secure authentication and data encryption scheme for the IoT-based medical care system, which can provide user anonymity and prevent the security threats of replay and password/sensed data disclosure attacks. Moreover, we modify the authentication process to reduce redundancy in protocol design, and the proposed scheme is more efficient in performance compared with previous related schemes. Finally, the proposed scheme is provably secure in the random oracle model under ECDHP. PMID:28644381

  1. A secure and efficient authentication and key agreement scheme based on ECC for telecare medicine information systems.

    PubMed

    Xu, Xin; Zhu, Ping; Wen, Qiaoyan; Jin, Zhengping; Zhang, Hua; He, Lian

    2014-01-01

    In the field of the Telecare Medicine Information System, recent researches have focused on consummating more convenient and secure healthcare delivery services for patients. In order to protect the sensitive information, various attempts such as access control have been proposed to safeguard patients' privacy in this system. However, these schemes suffered from some certain security defects and had costly consumption, which were not suitable for the telecare medicine information system. In this paper, based on the elliptic curve cryptography, we propose a secure and efficient two-factor mutual authentication and key agreement scheme to reduce the computational cost. Such a scheme enables to provide the patient anonymity by employing the dynamic identity. Compared with other related protocols, the security analysis and performance evaluation show that our scheme overcomes some well-known attacks and has a better performance in the telecare medicine information system.

  2. The costs and benefits of a migratory species under different management schemes.

    PubMed

    Skonhoft, Anders

    2005-07-01

    This paper analyses how different management schemes influence the exploitation and economics of a wildlife population--the moose (Alces alces)--that is both a value (harvesting income) and a pest (forestry damage). Two regimes are explored; the unified management scheme where the wildlife manager aims to find harvesting quotas that maximise the overall benefit of the moose population, and the market solution where the landowners follow their narrow self-interests and maximise their private profit. Because the moose is partly a migratory species, these regimes will differ both with respect to harvesting income and browsing damage, and the landowners will experience different profit. The unified scheme is very similar to the actual Scandinavian management, while the market solution is closer to the management policy one finds in North America. In the first part of the paper it is shown how the harvesting quotas and browsing damage under these two regimes are influenced by dispersal as well as other ecological and economic factors. In the last part of the paper it is demonstrated that under the unified management regime the present practice of neglecting migration may lead to sub-optimally sized populations of migrating moose and an overall economic loss. It is also shown that neglecting migration leads to a substantial profit transfer among the landowners. The model is supported by a real life numerical example.

  3. Consolidating the social health insurance schemes in China: towards an equitable and efficient health system.

    PubMed

    Meng, Qingyue; Fang, Hai; Liu, Xiaoyun; Yuan, Beibei; Xu, Jin

    2015-10-10

    Fragmentation in social health insurance schemes is an important factor for inequitable access to health care and financial protection for people covered by different health insurance schemes in China. To fulfil its commitment of universal health coverage by 2020, the Chinese Government needs to prioritise addressing this issue. After analysing the situation of fragmentation, this Review summarises efforts to consolidate health insurance schemes both in China and internationally. Rural migrants, elderly people, and those with non-communicable diseases in China will greatly benefit from consolidation of the existing health insurance schemes with extended funding pools, thereby narrowing the disparities among health insurance schemes in fund level and benefit package. Political commitments, institutional innovations, and a feasible implementation plan are the major elements needed for success in consolidation. Achievement of universal health coverage in China needs systemic strategies including consolidation of the social health insurance schemes.

  4. Augmented Z scheme blueprint for efficient solar water splitting system using quaternary chalcogenide absorber material.

    PubMed

    Sarswat, Prashant K; Bhattacharyya, Dhiman; Free, Michael L; Misra, Mano

    2016-02-07

    Photoelectrochemical hydrogen (H2) production from water is a key method of addressing energy needs using an environmentally friendly approach. In the last two decades we have witnessed the evolution of many different expensive catalysts, photoelectrodes and related technologies, especially those involving precious metals and use of acidic or basic electrolytes for hydrogen production. Cu2ZnSnS4 (CZTS) is a relatively new candidate in the category of efficient photocathodes, due to its high absorption coefficient and near optimal energy band gap. In this paper, we demonstrate photoelectrochemical viability of CZTS in combination with other photoanodes such as TiO2, BiVO4, and WO3 for H2 production with the use of an electrolyte of near neutral pH, a single redox mediator, and insignificant potential biasing. A systematic study was performed to understand CZTS performance with each photoanode, band energetics of CZTS with other photoanodes, impedance behavior of each photoelectrode, and utility of a CZTS photocell in place of a CZTS photocathode. Our assessment indicates that a protected CZTS photocell performs well when used in a Z-scheme containing TiO2 nanotubular array-CZTS or nanocrystalline WO3-CZTS. Preliminary experiments indicated that apart from band energetics, porosity and effective surface area of the photoanodes play a crucial role in determining the photoelectrochemical performance of the system.

  5. Novel buffer management scheme to moderate negative effects between TCP and UDP

    NASA Astrophysics Data System (ADS)

    Hori, Yoshiaki; Yamane, Kenji; Ikenaga, Takeshi; Oie, Yuji

    2001-07-01

    Multiplexing both responsive and unresponsive flows, namely TCP and UDP packets, in a single FIFO queue leads both flows into having an adverse effect on each other. In order to improve characteristics of queueing delay for UDP flows, we propose active buffer management schemes in diffserv network. We focus on MRED (Multiple RED) with HOL (head-of-line) priority control as buffer management scheme. We investigate the effectiveness of the scheme by means of simulations using ns version 2. Our simulation model has a dumbbell topology, which consists of ten sender nodes, ten receiver nodes and two routers. The five of ten senders generate CBR traffic, which will be sent by UDP, and the other five ones send bulk-data with TCP. The five CBR and the five TCP traffic share a bottleneck link between two routers. In case of FIFO, MRED with FIFO, and MRED with HOL schemes, by evaluating packet transmission delay and loss probability of CBR packet and TCP throughput, we examine how performance measures are affected by some parameters such as bandwidth of bottleneck link and thresholds of MRED. From our simulation results, MRED with FIFO is better than FIFO, but its performance is sensitive to thresholds of MRED with FIFO. On the other hand, MRED with HOL keeps stable rather than MRED in our simulation scenarios. We conclude that MRED with HOL scheme leads to low delay, low jitter, low drop probability for CBR flows as well as increases TCP throughput.

  6. Efficient compression scheme by use of the region division of elemental images on MALT in three-dimensional integral imaging

    NASA Astrophysics Data System (ADS)

    Kang, Ho-Hyun; Lee, Jung-Woo; Shin, Dong-Hak; Kim, Eun-Soo

    2010-02-01

    This paper addresses the efficient compression scheme of elemental image array (EIA) generated from the moving array lenslet technique (MALT) based on MPEG-4. The EIAs are picked-up by MALT controlling the spatial ray sampling of ray and which produces few EIAs that the positions of the lenslet arrays are rapidly vibrated in the lateral directions within the retention time of the afterimage of human eye. To enhance the similarity in each EIA picked-up by MALT, several EIAs obtained from MALT are regenerated by the collection of an elemental image occupied at the same position in each EIA. The newly generated each EIA has high similarity among adjacent elemental images. To illustrate the feasibility of the proposed scheme, some experiments are carried out to show the increased compression efficiency and we obtained the improved compression ratio of 12% compared to the unhandled compression scheme.

  7. Analysis and performance assessment of a fragment retransmission scheme for energy efficient IEEE 802.11 WLANs.

    PubMed

    Mafole, Prosper; Aritsugi, Masayoshi

    2016-01-01

    Backoff-free fragment retransmission (BFFR) scheme enhances the performance of legacy MAC layer fragmentation by eliminating contention overhead. The eliminated overhead is the result of backoff executed before a retransmission attempt is made when fragment transmission failure occurs within a fragment burst. This paper provides a mathematical analysis of BFFR energy efficiency and further assesses, by means of simulations, the energy efficiency, throughput and delay obtained when BFFR is used. The validity of the new scheme is evaluated in different scenarios namely, constant bit rate traffic, realistic bursty internet traffic, node mobility, rigid and elastic flows and their combinations at different traffic loads. We also evaluate and discuss the impact of BFFR on MAC fairness when the number of nodes is varied from 4 to 10. It is shown that BFFR has advantages over legacy MAC fragmentation scheme in all the scenarios.

  8. A 0.975 μW 10-bit 100 kS/s SAR ADC with an energy-efficient and area-efficient switching scheme

    NASA Astrophysics Data System (ADS)

    Hu, Yunfeng; Xiong, Chao; Li, Bin

    2017-07-01

    A 10-bit successive approximation register (SAR) analog-to-digital converter (ADC) with an energy-efficient and area-efficient switching scheme was presented. By using C-2C dummy capacitor and an extra reference Vcm for the last capacitor, the proposed switching scheme achieves 97.65% switching energy saving, 87.2% capacitor area reduction and 47.06% switches reduction, compare to conventional switching scheme. The ADC was implemented in a 180 nm CMOS technology 1.8 V power supply, at sampling rate of 100 kS/s, the ADC achieves an SNDR of 57.84 dB and consumes 0.975 μW, resulting in a figure-of-merit (FOM) of 15.3 fJ/conversion-step.

  9. Efficient Management of Biomedical Ontology Versions

    NASA Astrophysics Data System (ADS)

    Kirsten, Toralf; Hartung, Michael; Groß, Anika; Rahm, Erhard

    Ontologies have become very popular in life sciences and other domains. They mostly undergo continuous changes and new ontology versions are frequently released. However, current analysis studies do not consider the ontology changes reflected in different versions but typically limit themselves to a specific ontology version which may quickly become obsolete. To allow applications easy access to different ontology versions we propose a central and uniform management of the versions of different biomedical ontologies. The proposed database approach takes concept and structural changes of succeeding ontology versions into account thereby supporting different kinds of change analysis. Furthermore, it is very space-efficient by avoiding redundant storage of ontology components which remain unchanged in different versions. We evaluate the storage requirements and query performance of the proposed approach for the Gene Ontology.

  10. Efficient Low Dissipative High Order Schemes for Multiscale MHD Flows, I: Basic Theory

    NASA Technical Reports Server (NTRS)

    Sjoegreen, Bjoern; Yee, H. C.

    2003-01-01

    The objective of this paper is to extend our recently developed highly parallelizable nonlinear stable high order schemes for complex multiscale hydrodynamic applications to the viscous MHD equations. These schemes employed multiresolution wavelets as adaptive numerical dissipation controls t o limit the amount of and to aid the selection and/or blending of the appropriate types of dissipation to be used. The new scheme is formulated for both the conservative and non-conservative form of the MHD equations in curvilinear grids. The four advantages of the present approach over existing MHD schemes reported in the open literature are as follows. First, the scheme is constructed for long-time integrations of shock/turbulence/combustion MHD flows. Available schemes are too diffusive for long-time integrations and/or turbulence/combustion problems. Second, unlike exist- ing schemes for the conservative MHD equations which suffer from ill-conditioned eigen- decompositions, the present scheme makes use of a well-conditioned eigen-decomposition obtained from a minor modification of the eigenvectors of the non-conservative MHD equations t o solve the conservative form of the MHD equations. Third, this approach of using the non-conservative eigensystem when solving the conservative equations also works well in the context of standard shock-capturing schemes for the MHD equations. Fourth, a new approach to minimize the numerical error of the divergence-free magnetic condition for high order schemes is introduced. Numerical experiments with typical MHD model problems revealed the applicability of the newly developed schemes for the MHD equations.

  11. An efficient and secure dynamic ID-based authentication scheme for telecare medical information systems.

    PubMed

    Chen, Hung-Ming; Lo, Jung-Wen; Yeh, Chang-Kuo

    2012-12-01

    The rapidly increased availability of always-on broadband telecommunication environments and lower-cost vital signs monitoring devices bring the advantages of telemedicine directly into the patient's home. Hence, the control of access to remote medical servers' resources has become a crucial challenge. A secure authentication scheme between the medical server and remote users is therefore needed to safeguard data integrity, confidentiality and to ensure availability. Recently, many authentication schemes that use low-cost mobile devices have been proposed to meet these requirements. In contrast to previous schemes, Khan et al. proposed a dynamic ID-based remote user authentication scheme that reduces computational complexity and includes features such as a provision for the revocation of lost or stolen smart cards and a time expiry check for the authentication process. However, Khan et al.'s scheme has some security drawbacks. To remedy theses, this study proposes an enhanced authentication scheme that overcomes the weaknesses inherent in Khan et al.'s scheme and demonstrated this scheme is more secure and robust for use in a telecare medical information system.

  12. Key management schemes using routing information frames in secure wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Kamaev, V. A.; Finogeev, A. G.; Finogeev, A. A.; Parygin, D. S.

    2017-01-01

    The article considers the problems and objectives of key management for data encryption in wireless sensor networks (WSN) of SCADA systems. The structure of the key information in the ZigBee network and methods of keys obtaining are discussed. The use of a hybrid key management schemes is most suitable for WSN. The session symmetric key is used to encrypt the sensor data, asymmetric keys are used to encrypt the session key transmitted from the routing information. Three algorithms of hybrid key management using routing information frames determined by routing methods and the WSN topology are presented.

  13. Spectral bandwidth-efficient four-wave mixing minimization scheme for C-band dense wavelength division multiplexed system

    NASA Astrophysics Data System (ADS)

    Singh, Gurpreet; Singh, Maninder Lal

    2017-07-01

    A hybrid suboptimum channel separation (S-CS) scheme is presented. The distinct feature of the scheme is that it selectively minimizes the four-wave mixing (FWM) effect on the worst-affected channels and enhances the performance and spectral bandwidth efficiency in a controlled way. The scheme is helpful in the precise adjustment of tradeoff between immunity from FWM and spectral bandwidth requirement. The simulative comparison of the S-CS with optimum unequal channel separation (OUCS) and equal channel separation (ECS) schemes is performed to show its effectiveness. A dense wavelength division multiplexed system having a total capacity of 1.64 Tb/s in C band is implemented using the presented scheme. A maximum of 82 channels spaced at minimum CS of 50 GHz operating at a data rate of 20 Gb/s for each of the channels is realized using a S-CS (n=12) hybrid scheme. The simulations are performed in the presence of all the linear and nonlinear impairments and noises. A maximum of 480- and 300-km distances using SSMF and ITUT.G655 fibers, respectively, is realized using dispersion-compensating fibers for 82 channels. The ECS and hybrid OUCS can be realized to cover the same distances but with 73 and 79 channels, respectively, due to the realization problem and bandwidth inefficiency.

  14. An adaptive hybrid EnKF-OI scheme for efficient state-parameter estimation of reactive contaminant transport models

    NASA Astrophysics Data System (ADS)

    Gharamti, M. E.; Valstar, J.; Hoteit, I.

    2014-09-01

    Reactive contaminant transport models are used by hydrologists to simulate and study the migration and fate of industrial waste in subsurface aquifers. Accurate transport modeling of such waste requires clear understanding of the system’s parameters, such as sorption and biodegradation. In this study, we present an efficient sequential data assimilation scheme that computes accurate estimates of aquifer contamination and spatially variable sorption coefficients. This assimilation scheme is based on a hybrid formulation of the ensemble Kalman filter (EnKF) and optimal interpolation (OI) in which solute concentration measurements are assimilated via a recursive dual estimation of sorption coefficients and contaminant state variables. This hybrid EnKF-OI scheme is used to mitigate background covariance limitations due to ensemble under-sampling and neglected model errors. Numerical experiments are conducted with a two-dimensional synthetic aquifer in which cobalt-60, a radioactive contaminant, is leached in a saturated heterogeneous clayey sandstone zone. Assimilation experiments are investigated under different settings and sources of model and observational errors. Simulation results demonstrate that the proposed hybrid EnKF-OI scheme successfully recovers both the contaminant and the sorption rate and reduces their uncertainties. Sensitivity analyses also suggest that the adaptive hybrid scheme remains effective with small ensembles, allowing to reduce the ensemble size by up to 80% with respect to the standard EnKF scheme.

  15. Exploring efficiencies of SISO, multi-SISO, and MIMO AVC schemes for floor vibration control

    NASA Astrophysics Data System (ADS)

    Nyawako, Donald S.; Reynolds, Paul; Hudson, Malcolm J.

    2012-04-01

    Continued advancements in steel and concrete materials as well as improved computer-optimized designs are resulting in more efficient floor structures, which have longer spans and are more lightweight. In addition, there is a tendency for offices to be more open-plan with fewer internal partitions. These structures possess low and closely spaced natural frequencies, sometimes falling within the range of frequencies produced by human activities, as well as low damping levels. Vibration serviceability problems are thus arising more frequently than before. The tendency for developers to require floor structures suitable for a variety of types of occupation so as to increase their economic viability also has clear ramifications for their vibration serviceability. Active vibration control (AVC) is emerging as a viable technology for mitigation of human-induced vibrations in problem floors. Past AVC research work, as demonstrated in analytical studies and successfully implemented in field trials, have focused predominantly on collocated sensor and actuator pairs in SISO or multi-SISO direct-output feedback schemes, for example, direct velocity feedback (DVF). This paper demonstrates the potential benefits that may be derived from using model-based control approaches, for example, in isolating and controlling specific problematic frequencies only. The approaches investigated here comprise of independent modal space control (IMSC) and pole-placement controllers that are implemented in SISO, SIMO, and MIMO control structures. Both the analytical and experimental studies presented are based on a laboratory structure. Attenuations in target modes of vibration ranged between 15.0-27.0 dB in the analytical studies and experimental implementation for all the controllers studied. Further, both analytical studies and experimental implementation yielded a 70-89 % reduction in acceleration responses from two different walking frequencies.

  16. Efficient C1-continuous phase-potential upwind (C1-PPU) schemes for coupled multiphase flow and transport with gravity

    NASA Astrophysics Data System (ADS)

    Jiang, Jiamin; Younis, Rami M.

    2017-10-01

    In the presence of counter-current flow, nonlinear convergence problems may arise in implicit time-stepping when the popular phase-potential upwinding (PPU) scheme is used. The PPU numerical flux is non-differentiable across the co-current/counter-current flow regimes. This may lead to cycles or divergence in the Newton iterations. Recently proposed methods address improved smoothness of the numerical flux. The objective of this work is to devise and analyze an alternative numerical flux scheme called C1-PPU that, in addition to improving smoothness with respect to saturations and phase potentials, also improves the level of scalar nonlinearity and accuracy. C1-PPU involves a novel use of the flux limiter concept from the context of high-resolution methods, and allows a smooth variation between the co-current/counter-current flow regimes. The scheme is general and applies to fully coupled flow and transport formulations with an arbitrary number of phases. We analyze the consistency property of the C1-PPU scheme, and derive saturation and pressure estimates, which are used to prove the solution existence. Several numerical examples for two- and three-phase flows in heterogeneous and multi-dimensional reservoirs are presented. The proposed scheme is compared to the conventional PPU and the recently proposed Hybrid Upwinding schemes. We investigate three properties of these numerical fluxes: smoothness, nonlinearity, and accuracy. The results indicate that in addition to smoothness, nonlinearity may also be critical for convergence behavior and thus needs to be considered in the design of an efficient numerical flux scheme. Moreover, the numerical examples show that the C1-PPU scheme exhibits superior convergence properties for large time steps compared to the other alternatives.

  17. A Secure and Efficient Scalable Secret Image Sharing Scheme with Flexible Shadow Sizes

    PubMed Central

    Xie, Dong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2017-01-01

    In a general (k, n) scalable secret image sharing (SSIS) scheme, the secret image is shared by n participants and any k or more than k participants have the ability to reconstruct it. The scalability means that the amount of information in the reconstructed image scales in proportion to the number of the participants. In most existing SSIS schemes, the size of each image shadow is relatively large and the dealer does not has a flexible control strategy to adjust it to meet the demand of differen applications. Besides, almost all existing SSIS schemes are not applicable under noise circumstances. To address these deficiencies, in this paper we present a novel SSIS scheme based on a brand-new technique, called compressed sensing, which has been widely used in many fields such as image processing, wireless communication and medical imaging. Our scheme has the property of flexibility, which means that the dealer can achieve a compromise between the size of each shadow and the quality of the reconstructed image. In addition, our scheme has many other advantages, including smooth scalability, noise-resilient capability, and high security. The experimental results and the comparison with similar works demonstrate the feasibility and superiority of our scheme. PMID:28072851

  18. A Secure and Efficient Scalable Secret Image Sharing Scheme with Flexible Shadow Sizes.

    PubMed

    Xie, Dong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2017-01-01

    In a general (k, n) scalable secret image sharing (SSIS) scheme, the secret image is shared by n participants and any k or more than k participants have the ability to reconstruct it. The scalability means that the amount of information in the reconstructed image scales in proportion to the number of the participants. In most existing SSIS schemes, the size of each image shadow is relatively large and the dealer does not has a flexible control strategy to adjust it to meet the demand of differen applications. Besides, almost all existing SSIS schemes are not applicable under noise circumstances. To address these deficiencies, in this paper we present a novel SSIS scheme based on a brand-new technique, called compressed sensing, which has been widely used in many fields such as image processing, wireless communication and medical imaging. Our scheme has the property of flexibility, which means that the dealer can achieve a compromise between the size of each shadow and the quality of the reconstructed image. In addition, our scheme has many other advantages, including smooth scalability, noise-resilient capability, and high security. The experimental results and the comparison with similar works demonstrate the feasibility and superiority of our scheme.

  19. An energy-efficient data transmission scheme for remote state estimation and applications to a water-tank system.

    PubMed

    Li, Yunji; Li, Peng; Chen, Wen

    2017-09-01

    An energy-efficient data transmission scheme for remote state estimation is proposed and experimentally evaluated in this paper. This new transmission strategy is presented by proving an upper bound of the system performance. Stability of the remote estimator is proved under the condition that some of the observation measurements are lost in a random probability. An experimental platform of two coupled water tanks with a wireless sensor node is established to evaluate and verify the proposed transmission scheme. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Dynamic Key Management Schemes for Secure Group Access Control Using Hierarchical Clustering in Mobile Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Tsaur, Woei-Jiunn; Pai, Haw-Tyng

    2008-11-01

    The applications of group computing and communication motivate the requirement to provide group access control in mobile ad hoc networks (MANETs). The operation in MANETs' groups performs a decentralized manner and accommodated membership dynamically. Moreover, due to lack of centralized control, MANETs' groups are inherently insecure and vulnerable to attacks from both within and outside the groups. Such features make access control more challenging in MANETs. Recently, several researchers have proposed group access control mechanisms in MANETs based on a variety of threshold signatures. However, these mechanisms cannot actually satisfy MANETs' dynamic environments. This is because the threshold-based mechanisms cannot be achieved when the number of members is not up to the threshold value. Hence, by combining the efficient elliptic curve cryptosystem, self-certified public key cryptosystem and secure filter technique, we construct dynamic key management schemes based on hierarchical clustering for securing group access control in MANETs. Specifically, the proposed schemes can constantly accomplish secure group access control only by renewing the secure filters of few cluster heads, when a cluster head joins or leaves a cross-cluster. In such a new way, we can find that the proposed group access control scheme can be very effective for securing practical applications in MANETs.

  1. Key Management Schemes for Peer-to-Peer Multimedia Streaming Overlay Networks

    NASA Astrophysics Data System (ADS)

    Naranjo, J. A. M.; López-Ramos, J. A.; Casado, L. G.

    Key distribution for multimedia live streaming peer-to-peer overlay networks is a field still in its childhood stage. A scheme designed for networks of this kind must seek security and efficiency while keeping in mind the following restrictions: limited bandwidth, continuous playing, great audience size and clients churn. This paper introduces two novel schemes that allow a trade-off between security and efficiency by allowing to dynamically vary the number of levels used in the key hierarchy. These changes are motivated by great variations in audience size, and initiated by decision of the Key Server. Additionally, a comparative study of both is presented, focusing on security and audience size. Results show that larger key hierarchies can supply bigger audiences, but offer less security against statistical attacks. The opposite happens for shorter key hierarchies.

  2. Fiber-optic integration and efficient detection schemes for optomechanical resonators

    NASA Astrophysics Data System (ADS)

    Cohen, Justin D.

    optomechanical resonators to optical fibers, with an emphasis on fabrication processes and optical characterization. I will then proceed to describe a few experiments enabled by the fiber couplers. The first studies the performance of an optomechanical resonator as a precise sensor for continuous position measurement. The sensitivity of the measurement, limited by the detection efficiency of intracavity photons, is compared to the standard quantum limit imposed by the quantum properties of the laser probe light. The added noise of the measurement is seen to fall within a factor of 3 of the standard quantum limit, representing an order of magnitude improvement over previous experiments utilizing optomechanical crystals, and matching the performance of similar measurements in the microwave domain. The next experiment uses single photon counting to detect individual phonon emission and absorption events within the nanomechanical oscillator. The scattering of laser light from mechanical motion produces correlated photon-phonon pairs, and detection of the emitted photon corresponds to an effective phonon counting scheme. In the process of scattering, the coherence properties of the mechanical oscillation are mapped onto the reflected light. Intensity interferometry of the reflected light then allows measurement of the temporal coherence of the acoustic field. These correlations are measured for a range of experimental conditions, including the optomechanical amplification of the mechanics to a self-oscillation regime, and comparisons are drawn to a laser system for phonons. Finally, prospects for using phonon counting and intensity interferometry to produce non-classical mechanical states are detailed following recent proposals in literature.

  3. Energy efficiency through integrated environmental management.

    PubMed

    Benromdhane, Souad Ahmed

    2015-05-01

    Integrated environmental management became an economic necessity after industrial development proved to be unsustainable without consideration of environmental direct and indirect impacts. Energy dependency and air pollution along with climate change grew into major challenges facing developed and developing countries alike. Thus, a new global market structure emerged and changed the way we do trade. The search intensified for alternatives to petroleum. However, scientists, policy makers, and environmental activists agreed to focus on strategic conservation and optimization of energy use. Environmental concerns will remain partially unaddressed with the current pace of consumption because greenhouse gas emissions will continue to rise with economic growth. This paper discusses energy efficiency, steady integration of alternative sources, and increased use of best available technologies. Energy criteria developed for environmental labeling certification are presented. Our intention is to encourage manufacturers and service providers to supply consumers with less polluting and energy-consuming goods and services, inform consumers of the environmental and energy impacts, and thereby instill sustainable and responsible consumption. As several programs were initiated in developed countries, environmental labeling requirements created barriers to many exports manufactured in developing countries, affecting current world trade and putting more pressure on countries to meet those requirements. Defining an institutional and legal framework of environmental labeling is a key challenge in implementing such programs for critical economic sectors like tourism, textiles, and food production where energy needs are the most important aspect to control. A case study of Tunisia and its experience with eco-labeling is presented.

  4. An Energy-Efficient and Compact Clustering Scheme with Temporary Support Nodes for Cognitive Radio Sensor Networks

    PubMed Central

    Salim, Shelly; Moh, Sangman; Choi, Dongmin; Chung, Ilyong

    2014-01-01

    A cognitive radio sensor network (CRSN) is a wireless sensor network whose sensor nodes are equipped with cognitive radio capability. Clustering is one of the most challenging issues in CRSNs, as all sensor nodes, including the cluster head, have to use the same frequency band in order to form a cluster. However, due to the nature of heterogeneous channels in cognitive radio, it is difficult for sensor nodes to find a cluster head. This paper proposes a novel energy-efficient and compact clustering scheme named clustering with temporary support nodes (CENTRE). CENTRE efficiently achieves a compact cluster formation by adopting two-phase cluster formation with fixed duration. By introducing a novel concept of temporary support nodes to improve the cluster formation, the proposed scheme enables sensor nodes in a network to find a cluster head efficiently. The performance study shows that not only is the clustering process efficient and compact but it also results in remarkable energy savings that prolong the overall network lifetime. In addition, the proposed scheme decreases both the clustering overhead and the average distance between cluster heads and their members. PMID:25116905

  5. An energy-efficient and compact clustering scheme with temporary support nodes for cognitive radio sensor networks.

    PubMed

    Salim, Shelly; Moh, Sangman; Choi, Dongmin; Chung, Ilyong

    2014-08-11

    A cognitive radio sensor network (CRSN) is a wireless sensor network whose sensor nodes are equipped with cognitive radio capability. Clustering is one of the most challenging issues in CRSNs, as all sensor nodes, including the cluster head, have to use the same frequency band in order to form a cluster. However, due to the nature of heterogeneous channels in cognitive radio, it is difficult for sensor nodes to find a cluster head. This paper proposes a novel energy-efficient and compact clustering scheme named clustering with temporary support nodes (CENTRE). CENTRE efficiently achieves a compact cluster formation by adopting two-phase cluster formation with fixed duration. By introducing a novel concept of temporary support nodes to improve the cluster formation, the proposed scheme enables sensor nodes in a network to find a cluster head efficiently. The performance study shows that not only is the clustering process efficient and compact but it also results in remarkable energy savings that prolong the overall network lifetime. In addition, the proposed scheme decreases both the clustering overhead and the average distance between cluster heads and their members.

  6. An adaptive hybrid EnKF-OI scheme for efficient state-parameter estimation of reactive contaminant transport models

    NASA Astrophysics Data System (ADS)

    El Gharamti, Mohamad; Valstar, Johan; Hoteit, Ibrahim

    2014-05-01

    Reactive contaminant transport models are used by hydrologists to simulate and study the migration and fate of industrial waste in subsurface aquifers. Accurate transport modeling of such waste requires clear understanding of the system's parameters, such as sorption and biodegradation. In this study, we present an efficient sequential data assimilation scheme that computes accurate estimates of aquifer contamination and spatially variable sorption coefficients. This assimilation scheme is based on a hybrid formulation of the ensemble Kalman filter (EnKF) and optimal interpolation (OI) in which solute concentration measurements are assimilated via a recursive dual estimation of sorption coefficients and contaminant state variables. This hybrid EnKF-OI scheme is used to mitigate background covariance limitations due to ensemble under-sampling and neglected model errors. Numerical experiments are conducted with a two-dimensional synthetic aquifer in which cobalt-60, a radioactive contaminant, is leached in a saturated heterogeneous clayey sandstone zone. Assimilation experiments are investigated under different settings and sources of model and observational errors. Our results suggest that the proposed scheme allows a reduction of around 80% of the ensemble size as compared to the standard EnKF scheme.

  7. Efficient Low Dissipative High Order Schemes for Multiscale MHD Flows. II; Minimization of Delta * B Numerical Error

    NASA Technical Reports Server (NTRS)

    Sjoegreen, Bjoern; Yee, H. C.

    2003-01-01

    The generalization of a class of low-dissipative high order filter finite difference schemes for long time wave propagation of shock/turbulence/combustion compressible viscous gas dynamic flows to compressible MHD equations for structured curvilinear grids has been developed. The new scheme consists of a divergence free preserving high order spatial base scheme with a filter approach which can be divergence-free preserving depending on the type of filter operator being used, the method of applying the filter step, and the type of flow problem to be considered. Several variants of the filter approach that cater to different flow types are proposed. These filters provide a natural and efficient way for the minimization of the divergence of the magnetic field (Delta * B) numerical error in the sense that no standard divergence cleaning is required. Performance evaluation of these variants, and the key role that the proper treatment of their corresponding numerical boundary conditions can play will be illustrated. Many levels of grid refinement and detailed comparison with several commonly used compressible MHD shock-capturing schemes will be sought. For certain MHD 2-D test problems, divergence free preservation of the magnetic fields of these filter schemes has been achieved.

  8. Travelling Wave Pulse Coupled Oscillator (TWPCO) Using a Self-Organizing Scheme for Energy-Efficient Wireless Sensor Networks.

    PubMed

    Al-Mekhlafi, Zeyad Ghaleb; Hanapi, Zurina Mohd; Othman, Mohamed; Zukarnain, Zuriati Ahmad

    2017-01-01

    Recently, Pulse Coupled Oscillator (PCO)-based travelling waves have attracted substantial attention by researchers in wireless sensor network (WSN) synchronization. Because WSNs are generally artificial occurrences that mimic natural phenomena, the PCO utilizes firefly synchronization of attracting mating partners for modelling the WSN. However, given that sensor nodes are unable to receive messages while transmitting data packets (due to deafness), the PCO model may not be efficient for sensor network modelling. To overcome this limitation, this paper proposed a new scheme called the Travelling Wave Pulse Coupled Oscillator (TWPCO). For this, the study used a self-organizing scheme for energy-efficient WSNs that adopted travelling wave biologically inspired network systems based on phase locking of the PCO model to counteract deafness. From the simulation, it was found that the proposed TWPCO scheme attained a steady state after a number of cycles. It also showed superior performance compared to other mechanisms, with a reduction in the total energy consumption of 25%. The results showed that the performance improved by 13% in terms of data gathering. Based on the results, the proposed scheme avoids the deafness that occurs in the transmit state in WSNs and increases the data collection throughout the transmission states in WSNs.

  9. Travelling Wave Pulse Coupled Oscillator (TWPCO) Using a Self-Organizing Scheme for Energy-Efficient Wireless Sensor Networks

    PubMed Central

    Hanapi, Zurina Mohd; Othman, Mohamed; Zukarnain, Zuriati Ahmad

    2017-01-01

    Recently, Pulse Coupled Oscillator (PCO)-based travelling waves have attracted substantial attention by researchers in wireless sensor network (WSN) synchronization. Because WSNs are generally artificial occurrences that mimic natural phenomena, the PCO utilizes firefly synchronization of attracting mating partners for modelling the WSN. However, given that sensor nodes are unable to receive messages while transmitting data packets (due to deafness), the PCO model may not be efficient for sensor network modelling. To overcome this limitation, this paper proposed a new scheme called the Travelling Wave Pulse Coupled Oscillator (TWPCO). For this, the study used a self-organizing scheme for energy-efficient WSNs that adopted travelling wave biologically inspired network systems based on phase locking of the PCO model to counteract deafness. From the simulation, it was found that the proposed TWPCO scheme attained a steady state after a number of cycles. It also showed superior performance compared to other mechanisms, with a reduction in the total energy consumption of 25%. The results showed that the performance improved by 13% in terms of data gathering. Based on the results, the proposed scheme avoids the deafness that occurs in the transmit state in WSNs and increases the data collection throughout the transmission states in WSNs. PMID:28056020

  10. Simple pre-distortion schemes for improving the power efficiency of SOA-based IR-UWB over fiber systems

    NASA Astrophysics Data System (ADS)

    Taki, H.; Azou, S.; Hamie, A.; Al Housseini, A.; Alaeddine, A.; Sharaiha, A.

    2017-01-01

    In this paper, we investigate the usage of SOA for reach extension of an impulse radio over fiber system. Operating in the saturated regime translates into strong nonlinearities and spectral distortions, which drops the power efficiency of the propagated pulses. After studying the SOA response versus operating conditions, we have enhanced the system performance by applying simple analog pre-distortion schemes for various derivatives of the Gaussian pulse and their combination. A novel pulse shape has also been designed by linearly combining three basic Gaussian pulses, offering a very good spectral efficiency (> 55 %) for a high power (0 dBm) at the amplifier input. Furthermore, the potential of our technique has been examined considering a 1.5 Gbps-OOK and 0.75 Gbps-PPM modulation schemes. Pre-distortion proved an advantage for a large extension of optical link (150 km), with an inline amplification via SOA at 40 km.

  11. The role of agri-environment schemes in conservation and environmental management.

    PubMed

    Batáry, Péter; Dicks, Lynn V; Kleijn, David; Sutherland, William J

    2015-08-01

    Over half of the European landscape is under agricultural management and has been for millennia. Many species and ecosystems of conservation concern in Europe depend on agricultural management and are showing ongoing declines. Agri-environment schemes (AES) are designed partly to address this. They are a major source of nature conservation funding within the European Union (EU) and the highest conservation expenditure in Europe. We reviewed the structure of current AES across Europe. Since a 2003 review questioned the overall effectiveness of AES for biodiversity, there has been a plethora of case studies and meta-analyses examining their effectiveness. Most syntheses demonstrate general increases in farmland biodiversity in response to AES, with the size of the effect depending on the structure and management of the surrounding landscape. This is important in the light of successive EU enlargement and ongoing reforms of AES. We examined the change in effect size over time by merging the data sets of 3 recent meta-analyses and found that schemes implemented after revision of the EU's agri-environmental programs in 2007 were not more effective than schemes implemented before revision. Furthermore, schemes aimed at areas out of production (such as field margins and hedgerows) are more effective at enhancing species richness than those aimed at productive areas (such as arable crops or grasslands). Outstanding research questions include whether AES enhance ecosystem services, whether they are more effective in agriculturally marginal areas than in intensively farmed areas, whether they are more or less cost-effective for farmland biodiversity than protected areas, and how much their effectiveness is influenced by farmer training and advice? The general lesson from the European experience is that AES can be effective for conserving wildlife on farmland, but they are expensive and need to be carefully designed and targeted. © 2015 The Authors. Conservation Biology

  12. Design and simulation of a fuel cell hybrid emergency power system for a more electric aircraft: Evaluation of energy management schemes

    NASA Astrophysics Data System (ADS)

    Njoya Motapon, Souleman

    . The energy management schemes are compared based on the following criteria: the hydrogen consumption, the state of charges of the batteries and supercapacitors and the overall system efficiency. Moreover the stress on each energy source, which impacts their life cycle, are measured using a new approach based on the wavelet transform of their instantaneous power. A simulation model and an experimental test bench are developed to validate all analysis and performances. The main results obtained are as follows: the state machine control scheme provided a slightly better efficiency and stresses on the batteries and supercapacitors. The classical PI control and the proposed scheme had the lowest fuel consumption and more use of the battery energy. As expected, the lowest fuel cell stress and lowest use of the battery energy was achieved with the frequency decoupling and fuzzy logic scheme, but at the expense of more fuel consumption and lower overall efficiency. The DC bus or supercapacitor voltage was maintained nearly constant for all the schemes. Also, the proposed strategy performed slightly better than the ECMS in terms of efficiency and fuel consumption, with an increase in fuel economy by 3 %. The energy management scheme suitable for a MEA emergency system should be a multischeme EMS such that each scheme is chosen based on a specific criterion to prioritize. As an example, depending on the operating life of each energy source, the energy management strategy can be chosen to either minimise the stress on the fuel cell system, the battery system or supercapacitor system, hence maximizing the life cycle of the hybrid power system. Also if the target is to reduce the fuel consumption, the proposed or the classical PI strategies are better alternatives.

  13. An Efficient Transmission Power Control Scheme for Temperature Variation in Wireless Sensor Networks

    PubMed Central

    Lee, Jungwook; Chung, Kwangsue

    2011-01-01

    Wireless sensor networks collect data from several nodes dispersed at remote sites. Sensor nodes can be installed in harsh environments such as deserts, cities, and indoors, where the link quality changes considerably over time. Particularly, changes in transmission power may be caused by temperature, humidity, and other factors. In order to compensate for link quality changes, existing schemes detect the link quality changes between nodes and control transmission power through a series of feedback processes, but these approaches can cause heavy overhead with the additional control packets needed. In this paper, the change of the link quality according to temperature is examined through empirical experimentation. A new power control scheme combining both temperature-aware link quality compensation and a closed-loop feedback process to adapt to link quality changes is proposed. We prove that the proposed scheme effectively adapts the transmission power to the changing link quality with less control overhead and energy consumption. PMID:22163787

  14. An efficient transmission power control scheme for temperature variation in wireless sensor networks.

    PubMed

    Lee, Jungwook; Chung, Kwangsue

    2011-01-01

    Wireless sensor networks collect data from several nodes dispersed at remote sites. Sensor nodes can be installed in harsh environments such as deserts, cities, and indoors, where the link quality changes considerably over time. Particularly, changes in transmission power may be caused by temperature, humidity, and other factors. In order to compensate for link quality changes, existing schemes detect the link quality changes between nodes and control transmission power through a series of feedback processes, but these approaches can cause heavy overhead with the additional control packets needed. In this paper, the change of the link quality according to temperature is examined through empirical experimentation. A new power control scheme combining both temperature-aware link quality compensation and a closed-loop feedback process to adapt to link quality changes is proposed. We prove that the proposed scheme effectively adapts the transmission power to the changing link quality with less control overhead and energy consumption.

  15. Parallel implementation of 3D FFT with volumetric decomposition schemes for efficient molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Jung, Jaewoon; Kobayashi, Chigusa; Imamura, Toshiyuki; Sugita, Yuji

    2016-03-01

    Three-dimensional Fast Fourier Transform (3D FFT) plays an important role in a wide variety of computer simulations and data analyses, including molecular dynamics (MD) simulations. In this study, we develop hybrid (MPI+OpenMP) parallelization schemes of 3D FFT based on two new volumetric decompositions, mainly for the particle mesh Ewald (PME) calculation in MD simulations. In one scheme, (1d_Alltoall), five all-to-all communications in one dimension are carried out, and in the other, (2d_Alltoall), one two-dimensional all-to-all communication is combined with two all-to-all communications in one dimension. 2d_Alltoall is similar to the conventional volumetric decomposition scheme. We performed benchmark tests of 3D FFT for the systems with different grid sizes using a large number of processors on the K computer in RIKEN AICS. The two schemes show comparable performances, and are better than existing 3D FFTs. The performances of 1d_Alltoall and 2d_Alltoall depend on the supercomputer network system and number of processors in each dimension. There is enough leeway for users to optimize performance for their conditions. In the PME method, short-range real-space interactions as well as long-range reciprocal-space interactions are calculated. Our volumetric decomposition schemes are particularly useful when used in conjunction with the recently developed midpoint cell method for short-range interactions, due to the same decompositions of real and reciprocal spaces. The 1d_Alltoall scheme of 3D FFT takes 4.7 ms to simulate one MD cycle for a virus system containing more than 1 million atoms using 32,768 cores on the K computer.

  16. Particulate Photocatalyst Sheets Based on Carbon Conductor Layer for Efficient Z-Scheme Pure-Water Splitting at Ambient Pressure.

    PubMed

    Wang, Qian; Hisatomi, Takashi; Suzuki, Yohichi; Pan, Zhenhua; Seo, Jeongsuk; Katayama, Masao; Minegishi, Tsutomu; Nishiyama, Hiroshi; Takata, Tsuyoshi; Seki, Kazuhiko; Kudo, Akihiko; Yamada, Taro; Domen, Kazunari

    2017-02-01

    Development of sunlight-driven water splitting systems with high efficiency, scalability, and cost-competitiveness is a central issue for mass production of solar hydrogen as a renewable and storable energy carrier. Photocatalyst sheets comprising a particulate hydrogen evolution photocatalyst (HEP) and an oxygen evolution photocatalyst (OEP) embedded in a conductive thin film can realize efficient and scalable solar hydrogen production using Z-scheme water splitting. However, the use of expensive precious metal thin films that also promote reverse reactions is a major obstacle to developing a cost-effective process at ambient pressure. In this study, we present a standalone particulate photocatalyst sheet based on an earth-abundant, relatively inert, and conductive carbon film for efficient Z-scheme water splitting at ambient pressure. A SrTiO3:La,Rh/C/BiVO4:Mo sheet is shown to achieve unassisted pure-water (pH 6.8) splitting with a solar-to-hydrogen energy conversion efficiency (STH) of 1.2% at 331 K and 10 kPa, while retaining 80% of this efficiency at 91 kPa. The STH value of 1.0% is the highest among Z-scheme pure water splitting operating at ambient pressure. The working mechanism of the photocatalyst sheet is discussed on the basis of band diagram simulation. In addition, the photocatalyst sheet split pure water more efficiently than conventional powder suspension systems and photoelectrochemical parallel cells because H(+) and OH(-) concentration overpotentials and an IR drop between the HEP and OEP were effectively suppressed. The proposed carbon-based photocatalyst sheet, which can be used at ambient pressure, is an important alternative to (photo)electrochemical systems for practical solar hydrogen production.

  17. A Scheme for the Evaluation of Electron Delocalization and Conjugation Efficiency in Linearly π-Conjugated Systems.

    PubMed

    Bruschi, Maurizio; Limacher, Peter A; Hutter, Jürg; Lüthi, Hans Peter

    2009-03-10

    In this study, we present a scheme for the evaluation of electron delocalization and conjugation efficiency in lineraly π-conjugated systems. The scheme, based on the natural bond orbital theory, allows monitoring the evolution of electron delocalization along an extended conjugation path as well as its response to chemical modification. The scheme presented is evaluated and illustrated by means of a computational investigation of π-conjugation in all-trans polyacetylene [PA; H(-CH═CH)n-H], polydiacetylene [PDA, H(-C≡C-CH═CH)n-H], and polytriacetylene [PTA, H(-C≡C-CH═CH-C≡C)n-H] with up to 180 carbon atoms, all related by the number of ethynyl units incorporated in the chain. We are able to show that for short oligomers the incorporation of ethynyl spacers into the PA chain increases the π-delocalization energy, but, on the other hand, reduces the efficiency with which π-electron delocalization is promoted along the backbone. This explains the generally shorter effective conjugation lengths observed for the properties of the polyeneynes (PDA and PTA) relative to the polyenes (PA). It will also be shown that the reduced conjugation efficiency, within the NBO-based model presented in this work, can be related to the orbital interaction pattern along the π-conjugated chain. We will show that the orbital interaction energy pattern is characteristic for the type and the length of the backbone and may therefore serve as a descriptor for linearly π-conjugated chains.

  18. Hydro-geomorphic approaches to designing nature-based flood and drought management schemes

    NASA Astrophysics Data System (ADS)

    Hetherington, David; Large, Andy; Quinn, Paul

    2016-04-01

    The need for nature-based solutions to runoff management is more pressing than ever. If it is possible to calculate how much water needs to be managed and where the opportunities are in the landscape, then it would be a significant step forward in water resources management. Here we will show how basic hydro-geomorphic indices can guide a catchment manager in identifying the types of intervention that are appropriate at different scales. Using runoff management zones can provide key ecosystems services that make the whole catchment system function better. The key indicators are: a) The Topographic Wetness Index, for use in small catchment and on hillslopes for identifying overland flow pathways that can be managed to store and disconnect fast runoff; b) Strahler stream order to show which small channels can be directly managed to slow, store and filter flow and c) Geomorphic Indices that estimate the floodplain extent, related to stream order, where flood storage zones could be created to hold back large amounts of water. Estimating how much flood water and sediment can be managed by the addition of runoff attenuation features in a landscape could be very important to policy makers. If enough water can be stored in small, medium and extreme events, then the more severe issues of floods, pollution and drought could potentially be addressed, obviating calls for ever bigger and more complex flood protection schemes.

  19. Adaptive control schemes for improving dynamic performance of efficiency-optimized induction motor drives.

    PubMed

    Kumar, Navneet; Raj Chelliah, Thanga; Srivastava, S P

    2015-07-01

    Model Based Control (MBC) is one of the energy optimal controllers used in vector-controlled Induction Motor (IM) for controlling the excitation of motor in accordance with torque and speed. MBC offers energy conservation especially at part-load operation, but it creates ripples in torque and speed during load transition, leading to poor dynamic performance of the drive. This study investigates the opportunity for improving dynamic performance of a three-phase IM operating with MBC and proposes three control schemes: (i) MBC with a low pass filter (ii) torque producing current (iqs) injection in the output of speed controller (iii) Variable Structure Speed Controller (VSSC). The pre and post operation of MBC during load transition is also analyzed. The dynamic performance of a 1-hp, three-phase squirrel-cage IM with mine-hoist load diagram is tested. Test results are provided for the conventional field-oriented (constant flux) control and MBC (adjustable excitation) with proposed schemes. The effectiveness of proposed schemes is also illustrated for parametric variations. The test results and subsequent analysis confer that the motor dynamics improves significantly with all three proposed schemes in terms of overshoot/undershoot peak amplitude of torque and DC link power in addition to energy saving during load transitions. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Efficient conservative ADER schemes based on WENO reconstruction and space-time predictor in primitive variables

    NASA Astrophysics Data System (ADS)

    Zanotti, Olindo; Dumbser, Michael

    2016-01-01

    We present a new version of conservative ADER-WENO finite volume schemes, in which both the high order spatial reconstruction as well as the time evolution of the reconstruction polynomials in the local space-time predictor stage are performed in primitive variables, rather than in conserved ones. To obtain a conservative method, the underlying finite volume scheme is still written in terms of the cell averages of the conserved quantities. Therefore, our new approach performs the spatial WENO reconstruction twice: the first WENO reconstruction is carried out on the known cell averages of the conservative variables. The WENO polynomials are then used at the cell centers to compute point values of the conserved variables, which are subsequently converted into point values of the primitive variables. This is the only place where the conversion from conservative to primitive variables is needed in the new scheme. Then, a second WENO reconstruction is performed on the point values of the primitive variables to obtain piecewise high order reconstruction polynomials of the primitive variables. The reconstruction polynomials are subsequently evolved in time with a novel space-time finite element predictor that is directly applied to the governing PDE written in primitive form. The resulting space-time polynomials of the primitive variables can then be directly used as input for the numerical fluxes at the cell boundaries in the underlying conservative finite volume scheme. Hence, the number of necessary conversions from the conserved to the primitive variables is reduced to just one single conversion at each cell center. We have verified the validity of the new approach over a wide range of hyperbolic systems, including the classical Euler equations of gas dynamics, the special relativistic hydrodynamics (RHD) and ideal magnetohydrodynamics (RMHD) equations, as well as the Baer-Nunziato model for compressible two-phase flows. In all cases we have noticed that the new ADER

  1. A comparison of temperature and precipitation responses to different Earth radiation management geoengineering schemes

    NASA Astrophysics Data System (ADS)

    Crook, J. A.; Jackson, L. S.; Osprey, S. M.; Forster, P. M.

    2015-09-01

    Earth radiation management has been suggested as a way to rapidly counteract global warming in the face of a lack of mitigation efforts, buying time and avoiding potentially catastrophic warming. We compare six different radiation management schemes that use surface, troposphere, and stratosphere interventions in a single climate model in which we projected future climate from 2020 to 2099 based on RCP4.5. We analyze the surface air temperature responses to determine how effective the schemes are at returning temperature to its 1986-2005 climatology and analyze precipitation responses to compare side effects. We find crop albedo enhancement is largely ineffective at returning temperature to its 1986-2005 climatology. Desert albedo enhancement causes excessive cooling in the deserts and severe shifts in tropical precipitation. Ocean albedo enhancement, sea-spray geoengineering, cirrus cloud thinning, and stratospheric SO2 injection have the potential to cool more uniformly, but cirrus cloud thinning may not be able to cool by much more than 1 K globally. We find that of the schemes potentially able to return surface air temperature to 1986-2005 climatology under future greenhouse gas warming, none has significantly less severe precipitation side effects than other schemes. Despite different forcing patterns, ocean albedo enhancement, sea-spray geoengineering, cirrus cloud thinning, and stratospheric SO2 injection all result in large scale tropical precipitation responses caused by Hadley cell changes and land precipitation changes largely driven by thermodynamic changes. Widespread regional scale changes in precipitation over land are significantly different from the 1986-2005 climatology and would likely necessitate significant adaptation despite geoengineering.

  2. 24 CFR 1006.325 - Maintenance, management and efficient operation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... § 1006.325 Maintenance, management and efficient operation. (a) Written policies. The DHHL must develop... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Maintenance, management and efficient operation. 1006.325 Section 1006.325 Housing and Urban Development REGULATIONS RELATING TO HOUSING...

  3. 24 CFR 1006.325 - Maintenance, management and efficient operation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... § 1006.325 Maintenance, management and efficient operation. (a) Written policies. The DHHL must develop... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Maintenance, management and efficient operation. 1006.325 Section 1006.325 Housing and Urban Development REGULATIONS RELATING TO HOUSING...

  4. 24 CFR 1006.325 - Maintenance, management and efficient operation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... § 1006.325 Maintenance, management and efficient operation. (a) Written policies. The DHHL must develop... 24 Housing and Urban Development 4 2014-04-01 2014-04-01 false Maintenance, management and efficient operation. 1006.325 Section 1006.325 Housing and Urban Development REGULATIONS RELATING TO HOUSING...

  5. 24 CFR 1006.325 - Maintenance, management and efficient operation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... § 1006.325 Maintenance, management and efficient operation. (a) Written policies. The DHHL must develop... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Maintenance, management and efficient operation. 1006.325 Section 1006.325 Housing and Urban Development REGULATIONS RELATING TO HOUSING...

  6. Maximizing Thermal Efficiency and Optimizing Energy Management (Fact Sheet)

    SciTech Connect

    Not Available

    2012-03-01

    Researchers at the Thermal Test Facility (TTF) on the campus of the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colorado, are addressing maximizing thermal efficiency and optimizing energy management through analysis of efficient heating, ventilating, and air conditioning (HVAC) strategies, automated home energy management (AHEM), and energy storage systems.

  7. 24 CFR 1006.325 - Maintenance, management and efficient operation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... § 1006.325 Maintenance, management and efficient operation. (a) Written policies. The DHHL must develop... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Maintenance, management and efficient operation. 1006.325 Section 1006.325 Housing and Urban Development Regulations Relating to...

  8. A unified thermostat scheme for efficient configurational sampling for classical/quantum canonical ensembles via molecular dynamics

    NASA Astrophysics Data System (ADS)

    Zhang, Zhijun; Liu, Xinzijian; Chen, Zifei; Zheng, Haifeng; Yan, Kangyu; Liu, Jian

    2017-07-01

    We show a unified second-order scheme for constructing simple, robust, and accurate algorithms for typical thermostats for configurational sampling for the canonical ensemble. When Langevin dynamics is used, the scheme leads to the BAOAB algorithm that has been recently investigated. We show that the scheme is also useful for other types of thermostats, such as the Andersen thermostat and Nosé-Hoover chain, regardless of whether the thermostat is deterministic or stochastic. In addition to analytical analysis, two 1-dimensional models and three typical real molecular systems that range from the gas phase, clusters, to the condensed phase are used in numerical examples for demonstration. Accuracy may be increased by an order of magnitude for estimating coordinate-dependent properties in molecular dynamics (when the same time interval is used), irrespective of which type of thermostat is applied. The scheme is especially useful for path integral molecular dynamics because it consistently improves the efficiency for evaluating all thermodynamic properties for any type of thermostat.

  9. Efficient scheme for hybrid teleportation via entangled coherent states in circuit quantum electrodynamics

    PubMed Central

    Joo, Jaewoo; Ginossar, Eran

    2016-01-01

    We propose a deterministic scheme for teleporting an unknown qubit state through continuous-variable entangled states in superconducting circuits. The qubit is a superconducting two-level system and the bipartite quantum channel is a microwave photonic entangled coherent state between two cavities. A Bell-type measurement performed on the hybrid state of solid and photonic states transfers a discrete-variable unknown electronic state to a continuous-variable photonic cat state in a cavity mode. In order to facilitate the implementation of such complex protocols we propose a design for reducing the self-Kerr nonlinearity in the cavity. The teleporation scheme enables quantum information processing operations with circuit-QED based on entangled coherent states. These include state verification and single-qubit operations with entangled coherent states. These are shown to be experimentally feasible with the state of the art superconducting circuits. PMID:27245775

  10. Efficient scheme for hybrid teleportation via entangled coherent states in circuit quantum electrodynamics.

    PubMed

    Joo, Jaewoo; Ginossar, Eran

    2016-06-01

    We propose a deterministic scheme for teleporting an unknown qubit state through continuous-variable entangled states in superconducting circuits. The qubit is a superconducting two-level system and the bipartite quantum channel is a microwave photonic entangled coherent state between two cavities. A Bell-type measurement performed on the hybrid state of solid and photonic states transfers a discrete-variable unknown electronic state to a continuous-variable photonic cat state in a cavity mode. In order to facilitate the implementation of such complex protocols we propose a design for reducing the self-Kerr nonlinearity in the cavity. The teleporation scheme enables quantum information processing operations with circuit-QED based on entangled coherent states. These include state verification and single-qubit operations with entangled coherent states. These are shown to be experimentally feasible with the state of the art superconducting circuits.

  11. Efficient scheme for hybrid teleportation via entangled coherent states in circuit quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Joo, Jaewoo; Ginossar, Eran

    2016-06-01

    We propose a deterministic scheme for teleporting an unknown qubit state through continuous-variable entangled states in superconducting circuits. The qubit is a superconducting two-level system and the bipartite quantum channel is a microwave photonic entangled coherent state between two cavities. A Bell-type measurement performed on the hybrid state of solid and photonic states transfers a discrete-variable unknown electronic state to a continuous-variable photonic cat state in a cavity mode. In order to facilitate the implementation of such complex protocols we propose a design for reducing the self-Kerr nonlinearity in the cavity. The teleporation scheme enables quantum information processing operations with circuit-QED based on entangled coherent states. These include state verification and single-qubit operations with entangled coherent states. These are shown to be experimentally feasible with the state of the art superconducting circuits.

  12. An Efficience Scheme to Reduce Burst Loss Rate and Supporting Differentiated Services in All-Optical Networks

    NASA Astrophysics Data System (ADS)

    Garg, Amit Kumar

    2011-06-01

    Due to their one-way resource reservation mechanism, Optical Burst Switching (OBS) networks experience high bursts (thus packets) loss rate. In OBS networks, the contention is resolved either by dropping one of the contending bursts or more efficiently by dropping from one of the contending bursts only the parts that overlap with the other bursts. In both situations, only one data source will suffer the data loss in favor to the other. In this paper, an efficient scheme to reduce burst loss rate has been proposed in conjunction with an appropriate mechanism to provide differentiated service in order to support the quality of service (QoS) requirements of different applications. Simulation results show that the performance of the proposed scheme is better than existing mechanisms in terms of reducing burst (packets) loss. Numerical results show that the proposed scheme provides an accurate fit for the performance of the highest traffic class and lower bounds for the other traffic classes that are tighter than earlier known results.

  13. Efficient Evaluation System for Learning Management Systems

    ERIC Educational Resources Information Center

    Cavus, Nadire

    2009-01-01

    A learning management system (LMS) provides the platform for web-based learning environment by enabling the management, delivery, tracking of learning, testing, communication, registration process and scheduling. There are many LMS systems on the market that can be obtained for free or through payment. It has now become an important task to choose…

  14. A biometric signcryption scheme without bilinear pairing

    NASA Astrophysics Data System (ADS)

    Wang, Mingwen; Ren, Zhiyuan; Cai, Jun; Zheng, Wentao

    2013-03-01

    How to apply the entropy in biometrics into the encryption and remote authentication schemes to simplify the management of keys is a hot research area. Utilizing Dodis's fuzzy extractor method and Liu's original signcryption scheme, a biometric identity based signcryption scheme is proposed in this paper. The proposed scheme is more efficient than most of the previous proposed biometric signcryption schemes for that it does not need bilinear pairing computation and modular exponentiation computation which is time consuming largely. The analysis results show that under the CDH and DL hard problem assumption, the proposed scheme has the features of confidentiality and unforgeability simultaneously.

  15. Efficient numerical schemes for viscoplastic avalanches. Part 1: The 1D case

    SciTech Connect

    Fernández-Nieto, Enrique D.

    2014-05-01

    This paper deals with the numerical resolution of a shallow water viscoplastic flow model. Viscoplastic materials are characterized by the existence of a yield stress: below a certain critical threshold in the imposed stress, there is no deformation and the material behaves like a rigid solid, but when that yield value is exceeded, the material flows like a fluid. In the context of avalanches, it means that after going down a slope, the material can stop and its free surface has a non-trivial shape, as opposed to the case of water (Newtonian fluid). The model involves variational inequalities associated with the yield threshold: finite-volume schemes are used together with duality methods (namely Augmented Lagrangian and Bermúdez–Moreno) to discretize the problem. To be able to accurately simulate the stopping behavior of the avalanche, new schemes need to be designed, involving the classical notion of well-balancing. In the present context, it needs to be extended to take into account the viscoplastic nature of the material as well as general bottoms with wet/dry fronts which are encountered in geophysical geometries. We derived such schemes and numerical experiments are presented to show their performances.

  16. Maximum likelihood algorithm using an efficient scheme for computing sensitivities and parameter confidence intervals

    NASA Technical Reports Server (NTRS)

    Murphy, P. C.; Klein, V.

    1984-01-01

    Improved techniques for estimating airplane stability and control derivatives and their standard errors are presented. A maximum likelihood estimation algorithm is developed which relies on an optimization scheme referred to as a modified Newton-Raphson scheme with estimated sensitivities (MNRES). MNRES determines sensitivities by using slope information from local surface approximations of each output variable in parameter space. The fitted surface allows sensitivity information to be updated at each iteration with a significant reduction in computational effort compared to integrating the analytically-determined sensitivity equations or using a finite difference scheme. An aircraft estimation problem is solved using real flight data to compare MNRES with the commonly used modified Newton-Raphson technique; MNRES is found to be faster and more generally applicable. Parameter standard errors are determined using a random search technique. The confidence intervals obtained are compared with Cramer-Rao lower bounds at the same confidence level. It is observed that the nonlinearity of the cost function is an important factor in the relationship between Cramer-Rao bounds and the error bounds determined by the search technique.

  17. An Energy-Efficient Transmission Scheme for Real-Time Data in Wireless Sensor Networks

    PubMed Central

    Kim, Jin-Woo; Barrado, José Ramón Ramos; Jeon, Dong-Keun

    2015-01-01

    The Internet of things (IoT) is a novel paradigm where all things or objects in daily life can communicate with other devices and provide services over the Internet. Things or objects need identifying, sensing, networking and processing capabilities to make the IoT paradigm a reality. The IEEE 802.15.4 standard is one of the main communication protocols proposed for the IoT. The IEEE 802.15.4 standard provides the guaranteed time slot (GTS) mechanism that supports the quality of service (QoS) for the real-time data transmission. In spite of some QoS features in IEEE 802.15.4 standard, the problem of end-to-end delay still remains. In order to solve this problem, we propose a cooperative medium access scheme (MAC) protocol for real-time data transmission. We also evaluate the performance of the proposed scheme through simulation. The simulation results demonstrate that the proposed scheme can improve the network performance. PMID:26007722

  18. An energy-efficient transmission scheme for real-time data in wireless sensor networks.

    PubMed

    Kim, Jin-Woo; Barrado, José Ramón Ramos; Jeon, Dong-Keun

    2015-05-20

    The Internet of things (IoT) is a novel paradigm where all things or objects in daily life can communicate with other devices and provide services over the Internet. Things or objects need identifying, sensing, networking and processing capabilities to make the IoT paradigm a reality. The IEEE 802.15.4 standard is one of the main communication protocols proposed for the IoT. The IEEE 802.15.4 standard provides the guaranteed time slot (GTS) mechanism that supports the quality of service (QoS) for the real-time data transmission. In spite of some QoS features in IEEE 802.15.4 standard, the problem of end-to-end delay still remains. In order to solve this problem, we propose a cooperative medium access scheme (MAC) protocol for real-time data transmission. We also evaluate the performance of the proposed scheme through simulation. The simulation results demonstrate that the proposed scheme can improve the network performance.

  19. Maximum likelihood algorithm using an efficient scheme for computing sensitivities and parameter confidence intervals

    NASA Technical Reports Server (NTRS)

    Murphy, P. C.; Klein, V.

    1984-01-01

    Improved techniques for estimating airplane stability and control derivatives and their standard errors are presented. A maximum likelihood estimation algorithm is developed which relies on an optimization scheme referred to as a modified Newton-Raphson scheme with estimated sensitivities (MNRES). MNRES determines sensitivities by using slope information from local surface approximations of each output variable in parameter space. The fitted surface allows sensitivity information to be updated at each iteration with a significant reduction in computational effort compared to integrating the analytically-determined sensitivity equations or using a finite difference scheme. An aircraft estimation problem is solved using real flight data to compare MNRES with the commonly used modified Newton-Raphson technique; MNRES is found to be faster and more generally applicable. Parameter standard errors are determined using a random search technique. The confidence intervals obtained are compared with Cramer-Rao lower bounds at the same confidence level. It is observed that the nonlinearity of the cost function is an important factor in the relationship between Cramer-Rao bounds and the error bounds determined by the search technique.

  20. Online fault adaptive control for efficient resource management in Advanced Life Support Systems

    NASA Technical Reports Server (NTRS)

    Abdelwahed, Sherif; Wu, Jian; Biswas, Gautam; Ramirez, John; Manders, Eric-J

    2005-01-01

    This article presents the design and implementation of a controller scheme for efficient resource management in Advanced Life Support Systems. In the proposed approach, a switching hybrid system model is used to represent the dynamics of the system components and their interactions. The operational specifications for the controller are represented by utility functions, and the corresponding resource management problem is formulated as a safety control problem. The controller is designed as a limited-horizon online supervisory controller that performs a limited forward search on the state-space of the system at each time step, and uses the utility functions to decide on the best action. The feasibility and accuracy of the online algorithm can be assessed at design time. We demonstrate the effectiveness of the scheme by running a set of experiments on the Reverse Osmosis (RO) subsystem of the Water Recovery System (WRS).

  1. Online fault adaptive control for efficient resource management in Advanced Life Support Systems

    NASA Technical Reports Server (NTRS)

    Abdelwahed, Sherif; Wu, Jian; Biswas, Gautam; Ramirez, John; Manders, Eric-J

    2005-01-01

    This article presents the design and implementation of a controller scheme for efficient resource management in Advanced Life Support Systems. In the proposed approach, a switching hybrid system model is used to represent the dynamics of the system components and their interactions. The operational specifications for the controller are represented by utility functions, and the corresponding resource management problem is formulated as a safety control problem. The controller is designed as a limited-horizon online supervisory controller that performs a limited forward search on the state-space of the system at each time step, and uses the utility functions to decide on the best action. The feasibility and accuracy of the online algorithm can be assessed at design time. We demonstrate the effectiveness of the scheme by running a set of experiments on the Reverse Osmosis (RO) subsystem of the Water Recovery System (WRS).

  2. Online fault adaptive control for efficient resource management in Advanced Life Support Systems.

    PubMed

    Abdelwahed, Sherif; Wu, Jian; Biswas, Gautam; Ramirez, John; Manders, Eric-J

    2005-01-01

    This article presents the design and implementation of a controller scheme for efficient resource management in Advanced Life Support Systems. In the proposed approach, a switching hybrid system model is used to represent the dynamics of the system components and their interactions. The operational specifications for the controller are represented by utility functions, and the corresponding resource management problem is formulated as a safety control problem. The controller is designed as a limited-horizon online supervisory controller that performs a limited forward search on the state-space of the system at each time step, and uses the utility functions to decide on the best action. The feasibility and accuracy of the online algorithm can be assessed at design time. We demonstrate the effectiveness of the scheme by running a set of experiments on the Reverse Osmosis (RO) subsystem of the Water Recovery System (WRS).

  3. Survivable wavelength-division multiplexing passive optical network system with centralized protection routing scheme and efficient wavelength utilization

    NASA Astrophysics Data System (ADS)

    Zhou, Zhao; Xiao, Shilin; Bi, Meihua; Qi, Tao; Li, Pingqing; Hu, Weisheng

    2013-09-01

    A survivable wavelength-division multiplexing passive optical network (WDM-PON) with centralized protection scheme and colorless optical network units is proposed. The sideband channels generated via optical carrier suppression technique are used to carry both the downstream (DS) and the upstream (US) remodulated signals for two neighboring sub-PONs. By employing alternate path routing of sideband channels, the centralized protection scheme can provide reliable protection against any failure in feed fibers, remote node, and distribution fibers. The number of extra fibers is greatly reduced, and efficient utilization of wavelength resource is achieved. The feasibility of the proposed system is verified by 10-Gb/s DS and 1.25-Gb/s US signals over 25-km single-mode fiber transmission in both working and protection modes.

  4. Self-Consistent Filtering Scheme for Efficient Calculations of Observables via the Mixed Quantum-Classical Liouville Approach.

    PubMed

    Dell'Angelo, David; Hanna, Gabriel

    2016-02-09

    Over the past decade, several algorithms have been developed for calculating observables using mixed quantum-classical Liouville dynamics, which differ in how accurately they solve the quantum-classical Liouville equation (QCLE). One of these algorithms, known as sequential short-time propagation (SSTP), is a surface-hopping algorithm that solves the QCLE almost exactly, but obtaining converged values of observables requires very large ensembles of trajectories due to the rapidly growing statistical errors inherent to this algorithm. To reduce the ensemble sizes, two filtering schemes (viz., observable cutting and transition filtering) have been previously developed and effectively applied to both simple and complex models. However, these schemes are either ad hoc in nature or require significant trial and error for them to work as intended. In this study, we present a self-consistent scheme, which, in combination with a soundly motivated probability function used for the Monte Carlo sampling of the nonadiabatic transitions, avoids the ad hoc observable cutting and reduces the amount of trial and error required for the transition filtering to work. This scheme is tested on the spin-boson model, in the weak, intermediate, and strong coupling regimes. Our transition filtered results obtained using a newly proposed probability function, which favors the sampling of nonadiabatic transitions with small energy gaps, show a significant improvement in accuracy and efficiency for all coupling regimes over the results obtained using observable cutting and the original implementation of transition filtering and are comparable to those obtained using the combination of these two techniques. It is therefore expected that this novel scheme will substantially reduce ensemble sizes and simplify the computation of observables in more complex systems.

  5. Study on the energy-efficient scheme based on the interconnection of optical-network-units for next generation optical access network

    NASA Astrophysics Data System (ADS)

    Lv, Yunxin; Jiang, Ning; Qiu, Kun; Xue, Chenpeng

    2014-12-01

    An energy-efficient scheme based on the interconnection of optical network unit (ONU) is introduced, which can significantly reduce the energy consumption of the low-traffic operation. The energy consumption model for the ONU-interconnected optical access network (OAN) based on the electronic switch (ES) technology is established, and the energy efficiency of the proposed scheme is analyzed and compared with that of the OAN using optical switch (OS). The simulation results demonstrate that the ONU-interconnected scheme can efficiently reduce the energy consumption of OAN, and it shows a good energy consumption performance under daily traffic model.

  6. Multiuser Distortion Management Scheme for H.264 Video Transmission in OFDM Systems

    NASA Astrophysics Data System (ADS)

    Ha, Hojin; Kim, Young Yong

    In this paper, we propose a subcarrier resource allocation algorithm for managing the video quality degradation for multiuser orthogonal frequency division multiplex (OFDM) systems. The proposed algorithm exploits the unequal importance existing in different picture types for video coding and the diversity of subcarriers for multiuser systems. A model-based performance metric is first derived considering the error concealment and error propagation properties of the H.264 video coding structure. Based on the information on video quality enhancement existing in a packet to be transmitted, we propose the distortion management algorithm for balancing the subcarriers and power usages for each user and minimizing the overall video quality degradation. In the simulation results, the proposed algorithm demonstrates a more gradual video quality degradation for different numbers of users compared with other resource allocation schemes.

  7. Comparison of Aircraft Models and Integration Schemes for Interval Management in the TRACON

    NASA Technical Reports Server (NTRS)

    Neogi, Natasha; Hagen, George E.; Herencia-Zapana, Heber

    2012-01-01

    Reusable models of common elements for communication, computation, decision and control in air traffic management are necessary in order to enable simulation, analysis and assurance of emergent properties, such as safety and stability, for a given operational concept. Uncertainties due to faults, such as dropped messages, along with non-linearities and sensor noise are an integral part of these models, and impact emergent system behavior. Flight control algorithms designed using a linearized version of the flight mechanics will exhibit error due to model uncertainty, and may not be stable outside a neighborhood of the given point of linearization. Moreover, the communication mechanism by which the sensed state of an aircraft is fed back to a flight control system (such as an ADS-B message) impacts the overall system behavior; both due to sensor noise as well as dropped messages (vacant samples). Additionally simulation of the flight controller system can exhibit further numerical instability, due to selection of the integration scheme and approximations made in the flight dynamics. We examine the theoretical and numerical stability of a speed controller under the Euler and Runge-Kutta schemes of integration, for the Maintain phase for a Mid-Term (2035-2045) Interval Management (IM) Operational Concept for descent and landing operations. We model uncertainties in communication due to missed ADS-B messages by vacant samples in the integration schemes, and compare the emergent behavior of the system, in terms of stability, via the boundedness of the final system state. Any bound on the errors incurred by these uncertainties will play an essential part in a composable assurance argument required for real-time, flight-deck guidance and control systems,. Thus, we believe that the creation of reusable models, which possess property guarantees, such as safety and stability, is an innovative and essential requirement to assessing the emergent properties of novel airspace

  8. The Newmark scheme as velocity-stress time-staggering: an efficient PML implementation for spectral element simulations of elastodynamics

    NASA Astrophysics Data System (ADS)

    Festa, Gaetano; Vilotte, Jean-Pierre

    2005-06-01

    Perfectly matched layers (PMLs) provide an exponential decay, independent of the frequency, of any propagating field along an assigned direction without producing spurious reflections at the interface with the elastic volume. For this reason PMLs have been applied as absorbing boundary conditions (ABCs) and their efficiency in attenuating outgoing wave fields on the outskirts of numerical grids is more and more recognized. However, PMLs are designed for first-order differential equations and a natural extension to second-order Partial Differential Equations (PDEs) involves either additional variables in the time evolution scheme or convolutional operations. Both techniques are computationally expensive when implemented in a spectral element (SE) code and other ABCs (e.g. paraxial or standard sponge methods) still remain more attractive than PMLs. Here, an efficient second-order implementation of PMLs for SE is developed from interpreting the Newmark scheme as a time-staggered velocity-stress algorithm. The discrete equivalence with the standard scheme is based on an L2 approximation of the stress field, with the same polynomial order as the velocity. In this case, PMLs can be introduced as for first-order equations preserving the natural second-order time stepping. Subsequently, a non-classical frequency-dependent perfectly matched layer is introduced by moving the pole of the stretching along the imaginary axis. In this case, the absorption depends on the frequency and the layer switches from a transparent behaviour at low frequencies to a uniform absorption as the frequency goes to infinity. It turns out to be more efficient than classical PMLs in the absorption of the incident waves, as the grazing incidence approaches, at the cost of a memory variable for any split component. Finally, an extension of PMLs to general curvilinear coordinates is proposed.

  9. Efficiently computing pathway free energies: New approaches based on chain-of-replica and Non-Boltzmann Bennett reweighting schemes.

    PubMed

    Hudson, Phillip S; White, Justin K; Kearns, Fiona L; Hodoscek, Milan; Boresch, Stefan; Lee Woodcock, H

    2015-05-01

    Accurately modeling condensed phase processes is one of computation's most difficult challenges. Include the possibility that conformational dynamics may be coupled to chemical reactions, where multiscale (i.e., QM/MM) methods are needed, and this task becomes even more daunting. Free energy simulations (i.e., molecular dynamics), multiscale modeling, and reweighting schemes. Herein, we present two new approaches for mitigating the aforementioned challenges. The first is a new chain-of-replica method (off-path simulations, OPS) for computing potentials of mean force (PMFs) along an easily defined reaction coordinate. This development is coupled with a new distributed, highly-parallel replica framework (REPDstr) within the CHARMM package. Validation of these new schemes is carried out on two processes that undergo conformational changes. First is the simple torsional rotation of butane, while a much more challenging glycosidic rotation (in vacuo and solvated) is the second. Additionally, a new approach that greatly improves (i.e., possibly an order of magnitude) the efficiency of computing QM/MM PMFs is introduced and compared to standard schemes. Our efforts are grounded in the recently developed method for efficiently computing QM-based free energies (i.e., QM-Non-Boltzmann Bennett, QM-NBB). Again, we validate this new technique by computing the QM/MM PMF of butane's torsional rotation. The OPS-REPDstr method is a promising new approach that overcomes many limitations of standard pathway simulations in CHARMM. The combination of QM-NBB with pathway techniques is very promising as it offers significant advantages over current procedures. Efficiently computing potentials of mean force is a major, unresolved, area of interest. This article is part of a Special Issue entitled Recent developments of molecular dynamics. Copyright © 2014. Published by Elsevier B.V.

  10. An Efficient Radio Resource Allocation Scheme for Minimum Outage Probability Using Cooperation in OFDMA Systems

    NASA Astrophysics Data System (ADS)

    Jung, Junwoo; Park, Hyungwon; Lim, Jae-Sung

    Cooperation can increase the system performance by obtaining the spatial diversity. While most of the present works concentrate on the analysis of the cooperation based on the inter-user channel response and developing a scheme for higher cooperative diversity, in this paper, we focus on practical resource allocation in OFDMA systems. Since the user who uses the same center frequency can not receive the signal when transmitting, this constraint should be considered to apply the cooperation to OFDMA systems. In this paper, we propose the pair-based OFDMA frame structure that overcomes this constraint. Also in this frame structure to achieve the minimum outage probability of system, we select the best partner among the candidate neighbors and allocate the suitable subchannels to bandwidth requested users through a cooperative subchannel allocation (CSA) algorithm. In order to evaluate the proposed resource allocation scheme, we carry out simulations based on IEEE 802.16e. The simulation results show that our proposed algorithm offers smaller outage probability than one based on non-cooperative communications and we get the minimum outage probability when a threshold for selection of candidate neighbors is 10dB. We analyze that these results can be achieved by helping users located around the edge of the cell.

  11. Hybrid ARQ Error-Controlling Scheme for Robust and Efficient Transmission of UWB Body Area Networks

    NASA Astrophysics Data System (ADS)

    Suzuki, Haruka; Hernandez, Marco; Kohno, Ryuji

    This paper presents hybrid type-II automatic repeat request (H-ARQ) for wireless wearable body area networks (BANs) based on ultra wideband (UWB) technology. The proposed model is based on three schemes, namely, high rate optimized rate compatible punctured convolutional codes (HRO-RCPC), Reed Solomon (RS) invertible codes and their concatenation. Forward error correction (FEC) coding is combined with simple cyclic redundancy check (CRC) error detection. The performance is investigated for two channels: CM3 (on-body to on-body) and CM4 (on-body to a gateway) scenarios of the IEEE802.15.6 BAN channel models for BANs. It is shown that the improvement in performance in terms of throughput and error protection robustness is very significant. Thus, the proposed H-ARQ schemes can be employed and optimized to suit medical and non-medical applications. In particular we propose the use of FEC coding for non-medical applications as those require less stringent quality of service (QoS), while the incremental redundancy and ARQ configuration is utilized only for medical applications. Thus, higher QoS is guaranteed for medical application of BANs while allowing coexistence with non-medical applications.

  12. A novel power-efficient scheme asymmetrically and symmetrically clipping optical (ASCO)-OFDM for IM/DD optical systems

    NASA Astrophysics Data System (ADS)

    Wu, Nan; Bar-Ness, Yeheskel

    2015-12-01

    In this paper, we propose a novel scheme of orthogonal frequency division multiplexing (OFDM) for intensity modulation direct detection (IM/DD) optical systems. By using this novel scheme of an OFDM optical system, not only odd subcarriers but also even subcarriers can be modulated to transmit a clipping optical signal. A conventional asymmetrically clipping optical (ACO)-OFDM is applied to modulate odd subcarriers while even subcarriers are modulated by a novel technique called a symmetrically clipping optical (SCO)-OFDM. Although both the asymmetrically clipping noise caused by ACO-OFDM and the symmetrically clipping noise caused by SCO-OFDM fall onto the even subcarriers, the former interference can be estimated and removed at the receiver. Thus, SCO-OFDM symbols carried on the even subcarriers can be recovered by subtracting the estimated ACO-OFDM clipping noise from the received signal. Then the SCO-OFDM clipping noise can be removed by subtraction due to its special transmission format. Note that no DC bias added on all subcarriers makes this novel scheme achieve better performance in terms of both power efficiency and symbol error rate (SER).

  13. A classification scheme for analyzing mobile apps used to prevent and manage disease in late life.

    PubMed

    Wang, Aiguo; An, Ning; Lu, Xin; Chen, Hongtu; Li, Changqun; Levkoff, Sue

    2014-02-17

    There are several mobile apps that offer tools for disease prevention and management among older adults, and promote health behaviors that could potentially reduce or delay the onset of disease. A classification scheme that categorizes apps could be useful to both older adult app users and app developers. The objective of our study was to build and evaluate the effectiveness of a classification scheme that classifies mobile apps available for older adults in the "Health & Fitness" category of the iTunes App Store. We constructed a classification scheme for mobile apps according to three dimensions: (1) the Precede-Proceed Model (PPM), which classifies mobile apps in terms of predisposing, enabling, and reinforcing factors for behavior change; (2) health care process, specifically prevention versus management of disease; and (3) health conditions, including physical health and mental health. Content analysis was conducted by the research team on health and fitness apps designed specifically for older adults, as well as those applicable to older adults, released during the months of June and August 2011 and August 2012. Face validity was assessed by a different group of individuals, who were not related to the study. A reliability analysis was conducted to confirm the accuracy of the coding scheme of the sample apps in this study. After applying sample inclusion and exclusion criteria, a total of 119 apps were included in the study sample, of which 26/119 (21.8%) were released in June 2011, 45/119 (37.8%) in August 2011, and 48/119 (40.3%) in August 2012. Face validity was determined by interviewing 11 people, who agreed that this scheme accurately reflected the nature of this application. The entire study sample was successfully coded, demonstrating satisfactory inter-rater reliability by two independent coders (95.8% initial concordance and 100% concordance after consensus was reached). The apps included in the study sample were more likely to be used for the

  14. A Classification Scheme for Analyzing Mobile Apps Used to Prevent and Manage Disease in Late Life

    PubMed Central

    Wang, Aiguo; Lu, Xin; Chen, Hongtu; Li, Changqun; Levkoff, Sue

    2014-01-01

    Background There are several mobile apps that offer tools for disease prevention and management among older adults, and promote health behaviors that could potentially reduce or delay the onset of disease. A classification scheme that categorizes apps could be useful to both older adult app users and app developers. Objective The objective of our study was to build and evaluate the effectiveness of a classification scheme that classifies mobile apps available for older adults in the “Health & Fitness” category of the iTunes App Store. Methods We constructed a classification scheme for mobile apps according to three dimensions: (1) the Precede-Proceed Model (PPM), which classifies mobile apps in terms of predisposing, enabling, and reinforcing factors for behavior change; (2) health care process, specifically prevention versus management of disease; and (3) health conditions, including physical health and mental health. Content analysis was conducted by the research team on health and fitness apps designed specifically for older adults, as well as those applicable to older adults, released during the months of June and August 2011 and August 2012. Face validity was assessed by a different group of individuals, who were not related to the study. A reliability analysis was conducted to confirm the accuracy of the coding scheme of the sample apps in this study. Results After applying sample inclusion and exclusion criteria, a total of 119 apps were included in the study sample, of which 26/119 (21.8%) were released in June 2011, 45/119 (37.8%) in August 2011, and 48/119 (40.3%) in August 2012. Face validity was determined by interviewing 11 people, who agreed that this scheme accurately reflected the nature of this application. The entire study sample was successfully coded, demonstrating satisfactory inter-rater reliability by two independent coders (95.8% initial concordance and 100% concordance after consensus was reached). The apps included in the study sample

  15. An efficient hierarchical compression scheme for array-oriented climate data

    NASA Astrophysics Data System (ADS)

    Ghosh, S. S.; Baker, A. H.; Xu, H.

    2014-12-01

    High resolution climate models generate huge amounts of data. In recent days, with wide-spread availability of large computing resources, the amount of data is growing at an exponential rate. Archiving and curating these data for further research and analysis is a large challenge. Typically these data are stored as 4-byte real variables in the form of physical field variables in four dimensional spatio-temporal grids. Many of the existing lossy and non-lossy algorithms do not take full advantage of the uniform or nearly-uniform variation of these physical variables over spatio-temporal grids. We develop and implement an algorithm that compresses chunks of these physical variables in spatio-temporal domains to take advantage of this uniformity. One of the important features of this implementation is that it allows user to control the extent of spatio-temporal chunks, which can be tuned to maximize the compression factor. A second important feature is to be able to provide the capability to fine-tune the precision of the stored physical variables, according to the data type requirements. For example, we note that the climatological analysis involves averaging over field variables that in turn makes some insignificant bits of data irrelevant to the final result -- in our scheme users will be able to control the number of bits to be stored. In order to be able to compress further, we pass the stream through a lossless LZMA scheme. The amount of compression that can be achieved by this scheme depends on the uniformity of data and the required number of significant bits of information. We will report the compression factor that can be obtained when this package is applied for a wide range of climate variables with the constraint of keeping the climate analysis results statistically indistinguishable by following the analysis of Baker et.al.[1]. [1] A.H. Baker, H. Xu, J.M. Dennis, M.N. Levy, D. Nychka, S.A. Mickelson, J. Edwards, M. Vertenstein, A. Wegener, "A Methodology

  16. Spin-torque resonant expulsion of the vortex core for an efficient radiofrequency detection scheme

    NASA Astrophysics Data System (ADS)

    Jenkins, A. S.; Lebrun, R.; Grimaldi, E.; Tsunegi, S.; Bortolotti, P.; Kubota, H.; Yakushiji, K.; Fukushima, A.; de Loubens, G.; Klein, O.; Yuasa, S.; Cros, V.

    2016-04-01

    It has been proposed that high-frequency detectors based on the so-called spin-torque diode effect in spin transfer oscillators could eventually replace conventional Schottky diodes due to their nanoscale size, frequency tunability and large output sensitivity. Although a promising candidate for information and communications technology applications, the output voltage generated from this effect has still to be improved and, more pertinently, reduces drastically with decreasing radiofrequency (RF) current. Here we present a scheme for a new type of spintronics-based high-frequency detector based on the expulsion of the vortex core in a magnetic tunnel junction (MTJ). The resonant expulsion of the core leads to a large and sharp change in resistance associated with the difference in magnetoresistance between the vortex ground state and the final C-state configuration. Interestingly, this reversible effect is independent of the incoming RF current amplitude, offering a fast real-time RF threshold detector.

  17. A Polynomial Subset-Based Efficient Multi-Party Key Management System for Lightweight Device Networks.

    PubMed

    Mahmood, Zahid; Ning, Huansheng; Ghafoor, AtaUllah

    2017-03-24

    Wireless Sensor Networks (WSNs) consist of lightweight devices to measure sensitive data that are highly vulnerable to security attacks due to their constrained resources. In a similar manner, the internet-based lightweight devices used in the Internet of Things (IoT) are facing severe security and privacy issues because of the direct accessibility of devices due to their connection to the internet. Complex and resource-intensive security schemes are infeasible and reduce the network lifetime. In this regard, we have explored the polynomial distribution-based key establishment schemes and identified an issue that the resultant polynomial value is either storage intensive or infeasible when large values are multiplied. It becomes more costly when these polynomials are regenerated dynamically after each node join or leave operation and whenever key is refreshed. To reduce the computation, we have proposed an Efficient Key Management (EKM) scheme for multiparty communication-based scenarios. The proposed session key management protocol is established by applying a symmetric polynomial for group members, and the group head acts as a responsible node. The polynomial generation method uses security credentials and secure hash function. Symmetric cryptographic parameters are efficient in computation, communication, and the storage required. The security justification of the proposed scheme has been completed by using Rubin logic, which guarantees that the protocol attains mutual validation and session key agreement property strongly among the participating entities. Simulation scenarios are performed using NS 2.35 to validate the results for storage, communication, latency, energy, and polynomial calculation costs during authentication, session key generation, node migration, secure joining, and leaving phases. EKM is efficient regarding storage, computation, and communication overhead and can protect WSN-based IoT infrastructure.

  18. A Polynomial Subset-Based Efficient Multi-Party Key Management System for Lightweight Device Networks

    PubMed Central

    Mahmood, Zahid; Ning, Huansheng; Ghafoor, AtaUllah

    2017-01-01

    Wireless Sensor Networks (WSNs) consist of lightweight devices to measure sensitive data that are highly vulnerable to security attacks due to their constrained resources. In a similar manner, the internet-based lightweight devices used in the Internet of Things (IoT) are facing severe security and privacy issues because of the direct accessibility of devices due to their connection to the internet. Complex and resource-intensive security schemes are infeasible and reduce the network lifetime. In this regard, we have explored the polynomial distribution-based key establishment schemes and identified an issue that the resultant polynomial value is either storage intensive or infeasible when large values are multiplied. It becomes more costly when these polynomials are regenerated dynamically after each node join or leave operation and whenever key is refreshed. To reduce the computation, we have proposed an Efficient Key Management (EKM) scheme for multiparty communication-based scenarios. The proposed session key management protocol is established by applying a symmetric polynomial for group members, and the group head acts as a responsible node. The polynomial generation method uses security credentials and secure hash function. Symmetric cryptographic parameters are efficient in computation, communication, and the storage required. The security justification of the proposed scheme has been completed by using Rubin logic, which guarantees that the protocol attains mutual validation and session key agreement property strongly among the participating entities. Simulation scenarios are performed using NS 2.35 to validate the results for storage, communication, latency, energy, and polynomial calculation costs during authentication, session key generation, node migration, secure joining, and leaving phases. EKM is efficient regarding storage, computation, and communication overhead and can protect WSN-based IoT infrastructure. PMID:28338632

  19. Sensing and Efficient Inference for Identity Management

    DTIC Science & Technology

    2015-12-20

    graph correspond to observations, and edges are weighted with correlation measures that quantify positive or negative evidence for the hypothesis...Research Triangle Park, NC 27709-2211 Computer vision, correlation clustering, identity management REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S...integer program that describes the key data association problem: Nodes in a graph correspond to observations, and edges are weighted with correlation

  20. Inverse covariance simplification for efficient uncertainty management

    NASA Astrophysics Data System (ADS)

    Jalobeanu, A.; Gutiérrez, J. A.

    2007-11-01

    When it comes to manipulating uncertain knowledge such as noisy observations of physical quantities, one may ask how to do it in a simple way. Processing corrupted signals or images always propagates the uncertainties from the data to the final results, whether these errors are explicitly computed or not. When such error estimates are provided, it is crucial to handle them in such a way that their interpretation, or their use in subsequent processing steps, remain user-friendly and computationally tractable. A few authors follow a Bayesian approach and provide uncertainties as an inverse covariance matrix. Despite its apparent sparsity, this matrix contains many small terms that carry little information. Methods have been developed to select the most significant entries, through the use of information-theoretic tools for instance. One has to find a Gaussian pdf that is close enough to the posterior pdf, and with a small number of non-zero coefficients in the inverse covariance matrix. We propose to restrict the search space to Markovian models (where only neighbors can interact), well-suited to signals or images. The originality of our approach is in conserving the covariances between neighbors while setting to zero the entries of the inverse covariance matrix for all other variables. This fully constrains the solution, and the computation is performed via a fast, alternate minimization scheme involving quadratic forms. The Markovian structure advantageously reduces the complexity of Bayesian updating (where the simplified pdf is used as a prior). Moreover, uncertainties exhibit the same temporal or spatial structure as the data.

  1. Hierarchical adaptation scheme for multiagent data fusion and resource management in situation analysis

    NASA Astrophysics Data System (ADS)

    Benaskeur, Abder R.; Roy, Jean

    2001-08-01

    Sensor Management (SM) has to do with how to best manage, coordinate and organize the use of sensing resources in a manner that synergistically improves the process of data fusion. Based on the contextual information, SM develops options for collecting further information, allocates and directs the sensors towards the achievement of the mission goals and/or tunes the parameters for the realtime improvement of the effectiveness of the sensing process. Conscious of the important role that SM has to play in modern data fusion systems, we are currently studying advanced SM Concepts that would help increase the survivability of the current Halifax and Iroquois Class ships, as well as their possible future upgrades. For this purpose, a hierarchical scheme has been proposed for data fusion and resource management adaptation, based on the control theory and within the process refinement paradigm of the JDL data fusion model, and taking into account the multi-agent model put forward by the SASS Group for the situation analysis process. The novelty of this work lies in the unified framework that has been defined for tackling the adaptation of both the fusion process and the sensor/weapon management.

  2. An efficient locally one-dimensional finite-difference time-domain method based on the conformal scheme

    NASA Astrophysics Data System (ADS)

    Wei, Xiao-Kun; Shao, Wei; Shi, Sheng-Bing; Zhang, Yong; Wang, Bing-Zhong

    2015-07-01

    An efficient conformal locally one-dimensional finite-difference time-domain (LOD-CFDTD) method is presented for solving two-dimensional (2D) electromagnetic (EM) scattering problems. The formulation for the 2D transverse-electric (TE) case is presented and its stability property and numerical dispersion relationship are theoretically investigated. It is shown that the introduction of irregular grids will not damage the numerical stability. Instead of the staircasing approximation, the conformal scheme is only employed to model the curve boundaries, whereas the standard Yee grids are used for the remaining regions. As the irregular grids account for a very small percentage of the total space grids, the conformal scheme has little effect on the numerical dispersion. Moreover, the proposed method, which requires fewer arithmetic operations than the alternating-direction-implicit (ADI) CFDTD method, leads to a further reduction of the CPU time. With the total-field/scattered-field (TF/SF) boundary and the perfectly matched layer (PML), the radar cross section (RCS) of two 2D structures is calculated. The numerical examples verify the accuracy and efficiency of the proposed method. Project supported by the National Natural Science Foundation of China (Grant Nos. 61331007 and 61471105).

  3. A Hybrid Key Management Scheme for WSNs Based on PPBR and a Tree-Based Path Key Establishment Method

    PubMed Central

    Zhang, Ying; Liang, Jixing; Zheng, Bingxin; Chen, Wei

    2016-01-01

    With the development of wireless sensor networks (WSNs), in most application scenarios traditional WSNs with static sink nodes will be gradually replaced by Mobile Sinks (MSs), and the corresponding application requires a secure communication environment. Current key management researches pay less attention to the security of sensor networks with MS. This paper proposes a hybrid key management schemes based on a Polynomial Pool-based key pre-distribution and Basic Random key pre-distribution (PPBR) to be used in WSNs with MS. The scheme takes full advantages of these two kinds of methods to improve the cracking difficulty of the key system. The storage effectiveness and the network resilience can be significantly enhanced as well. The tree-based path key establishment method is introduced to effectively solve the problem of communication link connectivity. Simulation clearly shows that the proposed scheme performs better in terms of network resilience, connectivity and storage effectiveness compared to other widely used schemes. PMID:27070624

  4. A Hybrid Key Management Scheme for WSNs Based on PPBR and a Tree-Based Path Key Establishment Method.

    PubMed

    Zhang, Ying; Liang, Jixing; Zheng, Bingxin; Chen, Wei

    2016-04-09

    With the development of wireless sensor networks (WSNs), in most application scenarios traditional WSNs with static sink nodes will be gradually replaced by Mobile Sinks (MSs), and the corresponding application requires a secure communication environment. Current key management researches pay less attention to the security of sensor networks with MS. This paper proposes a hybrid key management schemes based on a Polynomial Pool-based key pre-distribution and Basic Random key pre-distribution (PPBR) to be used in WSNs with MS. The scheme takes full advantages of these two kinds of methods to improve the cracking difficulty of the key system. The storage effectiveness and the network resilience can be significantly enhanced as well. The tree-based path key establishment method is introduced to effectively solve the problem of communication link connectivity. Simulation clearly shows that the proposed scheme performs better in terms of network resilience, connectivity and storage effectiveness compared to other widely used schemes.

  5. Efficient High Order Central Schemes for Multi-Dimensional Hamilton-Jacobi Equations: Talk Slides

    NASA Technical Reports Server (NTRS)

    Bryson, Steve; Levy, Doron; Biegel, Brian R. (Technical Monitor)

    2002-01-01

    This viewgraph presentation presents information on the attempt to produce high-order, efficient, central methods that scale well to high dimension. The central philosophy is that the equations should evolve to the point where the data is smooth. This is accomplished by a cyclic pattern of reconstruction, evolution, and re-projection. One dimensional and two dimensional representational methods are detailed, as well.

  6. D-MSR: A Distributed Network Management Scheme for Real-Time Monitoring and Process Control Applications in Wireless Industrial Automation

    PubMed Central

    Zand, Pouria; Dilo, Arta; Havinga, Paul

    2013-01-01

    Current wireless technologies for industrial applications, such as WirelessHART and ISA100.11a, use a centralized management approach where a central network manager handles the requirements of the static network. However, such a centralized approach has several drawbacks. For example, it cannot cope with dynamicity/disturbance in large-scale networks in a real-time manner and it incurs a high communication overhead and latency for exchanging management traffic. In this paper, we therefore propose a distributed network management scheme, D-MSR. It enables the network devices to join the network, schedule their communications, establish end-to-end connections by reserving the communication resources for addressing real-time requirements, and cope with network dynamicity (e.g., node/edge failures) in a distributed manner. According to our knowledge, this is the first distributed management scheme based on IEEE 802.15.4e standard, which guides the nodes in different phases from joining until publishing their sensor data in the network. We demonstrate via simulation that D-MSR can address real-time and reliable communication as well as the high throughput requirements of industrial automation wireless networks, while also achieving higher efficiency in network management than WirelessHART, in terms of delay and overhead. PMID:23807687

  7. D-MSR: a distributed network management scheme for real-time monitoring and process control applications in wireless industrial automation.

    PubMed

    Zand, Pouria; Dilo, Arta; Havinga, Paul

    2013-06-27

    Current wireless technologies for industrial applications, such as WirelessHART and ISA100.11a, use a centralized management approach where a central network manager handles the requirements of the static network. However, such a centralized approach has several drawbacks. For example, it cannot cope with dynamicity/disturbance in large-scale networks in a real-time manner and it incurs a high communication overhead and latency for exchanging management traffic. In this paper, we therefore propose a distributed network management scheme, D-MSR. It enables the network devices to join the network, schedule their communications, establish end-to-end connections by reserving the communication resources for addressing real-time requirements, and cope with network dynamicity (e.g., node/edge failures) in a distributed manner. According to our knowledge, this is the first distributed management scheme based on IEEE 802.15.4e standard, which guides the nodes in different phases from joining until publishing their sensor data in the network. We demonstrate via simulation that D-MSR can address real-time and reliable communication as well as the high throughput requirements of industrial automation wireless networks, while also achieving higher efficiency in network management than WirelessHART, in terms of delay and overhead.

  8. CCS_WHMS: A Congestion Control Scheme for Wearable Health Management System.

    PubMed

    Kafi, Mohamed Amine; Ben Othman, Jalel; Bagaa, Miloud; Badache, Nadjib

    2015-12-01

    Wearable computing is becoming a more and more attracting field in the last years thanks to the miniaturisation of electronic devices. Wearable healthcare monitoring systems (WHMS) as an important client of wearable computing technology has gained a lot. Indeed, the wearable sensors and their surrounding healthcare applications bring a lot of benefits to patients, elderly people and medical staff, so facilitating their daily life quality. But from a research point of view, there is still work to accomplish in order to overcome the gap between hardware and software parts. In this paper, we target the problem of congestion control when all these healthcare sensed data have to reach the destination in a reliable manner that avoids repetitive transmission which wastes precious energy or leads to loss of important information in emergency cases, too. We propose a congestion control scheme CCS_WHMS that ensures efficient and fair data delivery while used in the body wearable system part or in the multi-hop inter bodies wearable ones to get the destination. As the congestion detection paradigm is very important in the control process, we do experimental tests to compare between state of the art congestion detection methods, using MICAz motes, in order to choose the appropriate one for our scheme.

  9. Do referral-management schemes reduce hospital outpatient attendances? Time-series evaluation of primary care referral management

    PubMed Central

    Cox, Jonathan MS; Steel, Nicholas; Clark, Allan B; Kumaravel, Bharathy; Bachmann, Max O

    2013-01-01

    Background Ninety-one per cent of primary care trusts were using some form of referral management in 2009, although evidence for its effectiveness is limited. Aim To assess the impact of three referral-management centres (RMCs) and two internal peer-review approaches to referral management on hospital outpatient attendance rates. Design and setting A retrospective time-series analysis of 376 000 outpatient attendances over 3 years from 85 practices divided into five groups, with 714 000 registered patients in one English primary care trust. Method The age-standardised GP-referred first outpatient monthly attendance rate was calculated for each group from April 2009 to March 2012. This was divided by the equivalent monthly England rate, to derive a rate ratio. Linear regression tested for association between the introduction of referral management and change in the outpatient attendance rate and rate ratio. Annual group budgets for referral management were obtained. Results Referral management was not associated with a reduction in the outpatient attendance rate in any group. There was a statistically significant increase in attendance rate in one group (a RMC), which had an increase of 1.05 attendances per 1000 persons per month (95% confidence interval = 0.46 to 1.64; attendance rate ratio increase of 0.07) after adjustment for autocorrelation. Mean annual budgets ranged from £0.55 to £6.23 per registered patient in 2011/2012. RMCs were more expensive (mean annual budget £5.18 per registered patient) than internal peer-review approaches (mean annual budget £0.97 per registered patient). Conclusion Referral-management schemes did not reduce outpatient attendance rates. RMCs were more expensive than internal peer review. PMID:23735409

  10. Spin torque resonant vortex core expulsion for an efficient radio-frequency detection scheme

    NASA Astrophysics Data System (ADS)

    Cros, V.; Jenkins, A. S.; Lebrun, R.; Bortolotti, P.; Grimaldi, E.; Tsunegi, S.; Kubota, H.; Yakushiji, K.; Fukushima, A.; Yuasa, S.

    It has been proposed by Tulaparkur et al.[1ref] that a high frequency detector based on the so called spin-diode effect in spin transfer oscillators could eventually replace conventional Schottky diodes, due to their nanoscale size, frequency tunability, and large output sensitivity. Although a promising candidate for ICT applications, the output voltage generated from this effect is consistently low. Here we present a scheme for a new type of spintronics-based high frequency detector based on the expulsion of the vortex core of a magnetic tunnel junction. The resonant expulsion of the core leads to a large and sharp change in resistance associated with the difference in magnetoresistance between the vortex ground state and the final C-state, which is predominantly in either the parallel or anti-parallel direction relative to the polariser layer. Interestingly, this reversible effect is independent of the incoming rf current amplitude, offering a compelling perspective for a fast real-time rf threshold detector. REF : EU FP7 Grant (MOSAIC No. ICT-FP7-317950 is acknowledged.

  11. Efficient checkpointing schemes for depletion perturbation solutions on memory-limited architectures

    SciTech Connect

    Stripling, H. F.; Adams, M. L.; Hawkins, W. D.

    2013-07-01

    We describe a methodology for decreasing the memory footprint and machine I/O load associated with the need to access a forward solution during an adjoint solve. Specifically, we are interested in the depletion perturbation equations, where terms in the adjoint Bateman and transport equations depend on the forward flux solution. Checkpointing is the procedure of storing snapshots of the forward solution to disk and using these snapshots to recompute the parts of the forward solution that are necessary for the adjoint solve. For large problems, however, the storage cost of just a few copies of an angular flux vector can exceed the available RAM on the host machine. We propose a methodology that does not checkpoint the angular flux vector; instead, we write and store converged source moments, which are typically of a much lower dimension than the angular flux solution. This reduces the memory footprint and I/O load of the problem, but requires that we perform single sweeps to reconstruct flux vectors on demand. We argue that this trade-off is exactly the kind of algorithm that will scale on advanced, memory-limited architectures. We analyze the cost, in terms of FLOPS and memory footprint, of five checkpointing schemes. We also provide computational results that support the analysis and show that the memory-for-work trade off does improve time to solution. (authors)

  12. Thermal management concepts for higher efficiency heavy vehicles.

    SciTech Connect

    Wambsganss, M. W.

    1999-05-19

    Thermal management is a cross-cutting technology that directly or indirectly affects engine performance, fuel economy, safety and reliability, aerodynamics, driver/passenger comfort, materials selection, emissions, maintenance, and component life. This review paper provides an assessment of thermal management for large trucks, particularly as it impacts these features. Observations arrived at from a review of the state of the art for thermal management for over-the-road trucks are highlighted and commented on. Trends in the large truck industry, pertinent engine truck design and performance objectives, and the implications of these relative to thermal management, are presented. Finally, new thermal management concepts for high efficiency vehicles are described.

  13. Modelling tools for managing Induced RiverBank Filtration MAR schemes

    NASA Astrophysics Data System (ADS)

    De Filippis, Giovanna; Barbagli, Alessio; Marchina, Chiara; Borsi, Iacopo; Mazzanti, Giorgio; Nardi, Marco; Vienken, Thomas; Bonari, Enrico; Rossetto, Rudy

    2017-04-01

    Induced RiverBank Filtration (IRBF) is a widely used technique in Managed Aquifer Recharge (MAR) schemes, when aquifers are hydraulically connected with surface water bodies, with proven positive effects on quality and quantity of groundwater. IRBF allows abstraction of a large volume of water, avoiding large decrease in groundwater heads. Moreover, thanks to the filtration process through the soil, the concentration of chemical species in surface water can be reduced, thus becoming an excellent resource for the production of drinking water. Within the FP7 MARSOL project (demonstrating Managed Aquifer Recharge as a SOLution to water scarcity and drought; http://www.marsol.eu/), the Sant'Alessio IRBF (Lucca, Italy) was used to demonstrate the feasibility and technical and economic benefits of managing IRBF schemes (Rossetto et al., 2015a). The Sant'Alessio IRBF along the Serchio river allows to abstract an overall amount of about 0.5 m3/s providing drinking water for 300000 people of the coastal Tuscany (mainly to the town of Lucca, Pisa and Livorno). The supplied water is made available by enhancing river bank infiltration into a high yield (10-2 m2/s transmissivity) sandy-gravelly aquifer by rising the river head and using ten vertical wells along the river embankment. A Decision Support System, consisting in connected measurements from an advanced monitoring network and modelling tools was set up to manage the IRBF. The modelling system is based on spatially distributed and physically based coupled ground-/surface-water flow and solute transport models integrated in the FREEWAT platform (developed within the H2020 FREEWAT project - FREE and Open Source Software Tools for WATer Resource Management; Rossetto et al., 2015b), an open source and public domain GIS-integrated modelling environment for the simulation of the hydrological cycle. The platform aims at improving water resource management by simplifying the application of EU water-related Directives and at

  14. Forward flux sampling-type schemes for simulating rare events: efficiency analysis.

    PubMed

    Allen, Rosalind J; Frenkel, Daan; ten Wolde, Pieter Rein

    2006-05-21

    We analyze the efficiency of several simulation methods which we have recently proposed for calculating rate constants for rare events in stochastic dynamical systems in or out of equilibrium. We derive analytical expressions for the computational cost of using these methods and for the statistical error in the final estimate of the rate constant for a given computational cost. These expressions can be used to determine which method to use for a given problem, to optimize the choice of parameters, and to evaluate the significance of the results obtained. We apply the expressions to the two-dimensional nonequilibrium rare event problem proposed by Maier and Stein [Phys. Rev. E 48, 931 (1993)]. For this problem, our analysis gives accurate quantitative predictions for the computational efficiency of the three methods.

  15. Costs, equity, efficiency and feasibility of identifying the poor in Ghana's National Health Insurance Scheme: empirical analysis of various strategies.

    PubMed

    Aryeetey, Genevieve Cecilia; Jehu-Appiah, Caroline; Spaan, Ernst; Agyepong, Irene; Baltussen, Rob

    2012-01-01

    To analyse the costs and evaluate the equity, efficiency and feasibility of four strategies to identify poor households for premium exemptions in Ghana's National Health Insurance Scheme (NHIS): means testing (MT), proxy means testing (PMT), participatory wealth ranking (PWR) and geographic targeting (GT) in urban, rural and semi-urban settings in Ghana. We conducted the study in 145-147 households per setting with MT as our gold standard strategy. We estimated total costs that included costs of household surveys and cost of premiums paid to the poor, efficiency (cost per poor person identified), equity (number of true poor excluded) and the administrative feasibility of implementation. The cost of exempting one poor individual ranged from US$15.87 to US$95.44; exclusion of the poor ranged between 0% and 73%. MT was most efficient and equitable in rural and urban settings with low-poverty incidence; GT was efficient and equitable in the semi-urban setting with high-poverty incidence. PMT and PWR were less equitable and inefficient although feasible in some settings. We recommend MT as optimal strategy in low-poverty urban and rural settings and GT as optimal strategy in high-poverty semi-urban setting. The study is relevant to other social and developmental programmes that require identification and exemptions of the poor in low-income countries. © 2011 Blackwell Publishing Ltd.

  16. The Millennium Dome "Watercycle" experiment: to evaluate water efficiency and customer perception at a recycling scheme for 6 million visitors.

    PubMed

    Hills, S; Birks, R; McKenzie, B

    2002-01-01

    Thames Water's "Watercycle" project at the Millennium Dome was one of the largest in-building recycling schemes in Europe, designed to supply up to 500 m3/d of reclaimed water for WC and urinal flushing. It catered for over 6 million visitors in the year 2000. Overall, 55% of the water demand at the Dome was met by reclaimed water. The site was also one of the most comprehensive studies ever carried out of water conservation in a public environment, evaluating a range of water efficient appliances and researching visitor perceptions of reclaimed water. Within the Dome there were six identical core buildings housing the washrooms, which were equipped with a variety of different water-efficient devices for comparison. Water usage by the different appliances was monitored using a sophisticated metering and telemetry system. The importance of correct installation and maintenance of "high tech" water efficient devices was highlighted during the research programme, as some water wastage occurred due to poor installation. The results prove that metering should complement any large-scale water efficient system, so that any faults with the appliances can be quickly identified. The visitor survey showed very positive attitudes to the use of reclaimed water for non-potable uses.

  17. Natural Resource Management Schemes as Entry Points for Integrated Landscape Approaches: Evidence from Ghana and Burkina Faso.

    PubMed

    Foli, Samson; Ros-Tonen, Mirjam A F; Reed, James; Sunderland, Terry

    2017-04-20

    In recognition of the failures of sectoral approaches to overcome global challenges of biodiversity loss, climate change, food insecurity and poverty, scientific discourse on biodiversity conservation and sustainable development is shifting towards integrated landscape governance arrangements. Current landscape initiatives however very much depend on external actors and funding, raising the question of whether, and how, and under what conditions, locally embedded resource management schemes can serve as entry points for the implementation of integrated landscape approaches. This paper assesses the entry point potential for three established natural resource management schemes in West Africa that target landscape degradation with involvement of local communities: the Chantier d'Aménagement Forestier scheme encompassing forest management sites across Burkina Faso and the Modified Taungya System and community wildlife resource management initiatives in Ghana. Based on a review of the current literature, we analyze the extent to which design principles that define a landscape approach apply to these schemes. We found that the CREMA meets most of the desired criteria, but that its scale may be too limited to guarantee effective landscape governance, hence requiring upscaling. Conversely, the other two initiatives are strongly lacking in their design principles on fundamental components regarding integrated approaches, continual learning, and capacity building. Monitoring and evaluation bodies and participatory learning and negotiation platforms could enhance the schemes' alignment with integrated landscape approaches.

  18. Efficient training schemes that improve the forecast quality of a supermodel

    NASA Astrophysics Data System (ADS)

    Schevenhoven, Francine; Selten, Frank; Duane, Gregory; Keenlyside, Noel

    2017-04-01

    Weather and climate models have improved steadily over time as witnessed by objective skill scores, although they remain imperfect. Given these imperfect models, predictions might be improved by combining them dynamically into a so-called "supermodel". In contrast to the standard multi-model ensemble approach, the models exchange information during the simulation, which leads to new solutions. In this study we explore different techniques to create such a supermodel. The techniques are applied to global climate models. The results indicate that the techniques are computationally efficient and lead to supermodels with superior forecast quality and climatology compared to the individual models or the standard multi-model ensemble approach.

  19. Lightweight Sensor Authentication Scheme for Energy Efficiency in Ubiquitous Computing Environments

    PubMed Central

    Lee, Jaeseung; Sung, Yunsick; Park, Jong Hyuk

    2016-01-01

    The Internet of Things (IoT) is the intelligent technologies and services that mutually communicate information between humans and devices or between Internet-based devices. In IoT environments, various device information is collected from the user for intelligent technologies and services that control the devices. Recently, wireless sensor networks based on IoT environments are being used in sectors as diverse as medicine, the military, and commerce. Specifically, sensor techniques that collect relevant area data via mini-sensors after distributing smart dust in inaccessible areas like forests or military zones have been embraced as the future of information technology. IoT environments that utilize smart dust are composed of the sensor nodes that detect data using wireless sensors and transmit the detected data to middle nodes. Currently, since the sensors used in these environments are composed of mini-hardware, they have limited memory, processing power, and energy, and a variety of research that aims to make the best use of these limited resources is progressing. This paper proposes a method to utilize these resources while considering energy efficiency, and suggests lightweight mutual verification and key exchange methods based on a hash function that has no restrictions on operation quantity, velocity, and storage space. This study verifies the security and energy efficiency of this method through security analysis and function evaluation, comparing with existing approaches. The proposed method has great value in its applicability as a lightweight security technology for IoT environments. PMID:27916962

  20. Lightweight Sensor Authentication Scheme for Energy Efficiency in Ubiquitous Computing Environments.

    PubMed

    Lee, Jaeseung; Sung, Yunsick; Park, Jong Hyuk

    2016-12-01

    The Internet of Things (IoT) is the intelligent technologies and services that mutually communicate information between humans and devices or between Internet-based devices. In IoT environments, various device information is collected from the user for intelligent technologies and services that control the devices. Recently, wireless sensor networks based on IoT environments are being used in sectors as diverse as medicine, the military, and commerce. Specifically, sensor techniques that collect relevant area data via mini-sensors after distributing smart dust in inaccessible areas like forests or military zones have been embraced as the future of information technology. IoT environments that utilize smart dust are composed of the sensor nodes that detect data using wireless sensors and transmit the detected data to middle nodes. Currently, since the sensors used in these environments are composed of mini-hardware, they have limited memory, processing power, and energy, and a variety of research that aims to make the best use of these limited resources is progressing. This paper proposes a method to utilize these resources while considering energy efficiency, and suggests lightweight mutual verification and key exchange methods based on a hash function that has no restrictions on operation quantity, velocity, and storage space. This study verifies the security and energy efficiency of this method through security analysis and function evaluation, comparing with existing approaches. The proposed method has great value in its applicability as a lightweight security technology for IoT environments.

  1. An Efficient Image Encryption Scheme Based on a Peter De Jong Chaotic Map and a RC4 Stream Cipher

    NASA Astrophysics Data System (ADS)

    Hanchinamani, Gururaj; Kulkarni, Linganagouda

    2015-09-01

    Security is a vital issue in communication and storage of the images and encryption is one of the ways to ensure the security. This paper proposes an efficient image encryption scheme based on a Peter De Jong chaotic map and a RC4 stream cipher. A Peter De Jong map is employed to determine the initial keys for the RC4 stream generator and also during permutation stage. The RC4 stream generator is utilized to generate the pseudo random numbers for the pixel value rotation and diffusion operations. Each encryption round is comprised of three stages: permutation, pixel value rotation and diffusion. The permutation is based on scrambling the rows and columns, in addition, circular rotations of the rows and columns in alternate orientations. The second stage circularly rotates each and every pixel value by utilizing M × N pseudo random numbers. The last stage carries out the diffusion twice by scanning the image in two different ways. Each of the two diffusions accomplishes the diffusion in two orientations (forward and backward) with two previously diffused pixels and two pseudo random numbers. The security and performance of the proposed method is assessed thoroughly by using key space, statistical, differential, entropy and performance analysis. Moreover, two rounds of the call to the encrypt function provide the sufficient security. The experimental results show that the proposed encryption scheme is computationally fast with high security.

  2. An efficient and stable hydrodynamic model with novel source term discretization schemes for overland flow and flood simulations

    NASA Astrophysics Data System (ADS)

    Xia, Xilin; Liang, Qiuhua; Ming, Xiaodong; Hou, Jingming

    2017-05-01

    Numerical models solving the full 2-D shallow water equations (SWEs) have been increasingly used to simulate overland flows and better understand the transient flow dynamics of flash floods in a catchment. However, there still exist key challenges that have not yet been resolved for the development of fully dynamic overland flow models, related to (1) the difficulty of maintaining numerical stability and accuracy in the limit of disappearing water depth and (2) inaccurate estimation of velocities and discharges on slopes as a result of strong nonlinearity of friction terms. This paper aims to tackle these key research challenges and present a new numerical scheme for accurately and efficiently modeling large-scale transient overland flows over complex terrains. The proposed scheme features a novel surface reconstruction method (SRM) to correctly compute slope source terms and maintain numerical stability at small water depth, and a new implicit discretization method to handle the highly nonlinear friction terms. The resulting shallow water overland flow model is first validated against analytical and experimental test cases and then applied to simulate a hypothetic rainfall event in the 42 km2 Haltwhistle Burn, UK.

  3. Developing a computationally efficient dynamic multilevel hybrid optimization scheme using multifidelity model interactions.

    SciTech Connect

    Hough, Patricia Diane (Sandia National Laboratories, Livermore, CA); Gray, Genetha Anne (Sandia National Laboratories, Livermore, CA); Castro, Joseph Pete Jr.; Giunta, Anthony Andrew

    2006-01-01

    Many engineering application problems use optimization algorithms in conjunction with numerical simulators to search for solutions. The formulation of relevant objective functions and constraints dictate possible optimization algorithms. Often, a gradient based approach is not possible since objective functions and constraints can be nonlinear, nonconvex, non-differentiable, or even discontinuous and the simulations involved can be computationally expensive. Moreover, computational efficiency and accuracy are desirable and also influence the choice of solution method. With the advent and increasing availability of massively parallel computers, computational speed has increased tremendously. Unfortunately, the numerical and model complexities of many problems still demand significant computational resources. Moreover, in optimization, these expenses can be a limiting factor since obtaining solutions often requires the completion of numerous computationally intensive simulations. Therefore, we propose a multifidelity optimization algorithm (MFO) designed to improve the computational efficiency of an optimization method for a wide range of applications. In developing the MFO algorithm, we take advantage of the interactions between multi fidelity models to develop a dynamic and computational time saving optimization algorithm. First, a direct search method is applied to the high fidelity model over a reduced design space. In conjunction with this search, a specialized oracle is employed to map the design space of this high fidelity model to that of a computationally cheaper low fidelity model using space mapping techniques. Then, in the low fidelity space, an optimum is obtained using gradient or non-gradient based optimization, and it is mapped back to the high fidelity space. In this paper, we describe the theory and implementation details of our MFO algorithm. We also demonstrate our MFO method on some example problems and on two applications: earth penetrators and

  4. Efficient and extendible class scheme for the combined reaction-diffusion of multiple molecular species

    NASA Astrophysics Data System (ADS)

    Stella, Sabrina; Chignola, Roberto; Milotti, Edoardo

    2014-03-01

    When dealing with large numbers of cells in biophysical simulations, it is important to properly manage the different substances that diffuse and react in and around cells. Although in an object-oriented programming environment it seems more natural to define cells as the basic objects, it turns out that individual substances are better suited to take this role. Here we describe the biophysical problem and our computational solution, and display the results obtained with a toy model. We find that the new implementation does not decrease performance and yet it leads to a much better structured and modular code. This will make more realistic programs with many molecular pathways much more modular and readily extendible.

  5. High speed sense amplifier with efficient pre-charge scheme for PCM in the 28nm process

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Chen, Houpeng; Fan, Xi; Lei, Yu; Hu, Jiajun; Li, Xiaoyun; Wang, Qian; Song, Zhitang

    2016-10-01

    An improved sense amplifier with speed-up pre-charge scheme is introduced in this paper. What's more, in order to avoid unexpected fatal damage while reading operation, clamp voltage is adopted. Distinguished with the conventional current sense amplifier, the proposed sense amplifier shortens not only the read access time by reducing the charging time due to parasite capacitor of storage cells but also the delay time because of the RC delay on wire by using two branches of pre-charge circuit at the both ends of bit lines. The simulation result taken in SMIC 28nm process shows that, with 1Kb PCM array, the proposed sense amplifier can efficiently reduce the access time from 33.7ns to 16.5ns.

  6. ROSA: Resource-Oriented Service Management Schemes for Web of Things in a Smart Home.

    PubMed

    Liao, Chun-Feng; Chen, Peng-Yu

    2017-09-21

    A Pervasive-computing-enriched smart home environment, which contains many embedded and tiny intelligent devices and sensors coordinated by service management mechanisms, is capable of anticipating intentions of occupants and providing appropriate services accordingly. Although there are a wealth of research achievements in recent years, the degree of market acceptance is still low. The main reason is that most of the devices and services in such environments depend on particular platform or technology, making it hard to develop an application by composing the devices or services. Meanwhile, the concept of Web of Things (WoT) is becoming popular recently. Based on WoT, the developers can build applications based on popular web tools or technologies. Consequently, the objective of this paper is to propose a set of novel WoT-driven plug-and-play service management schemes for a smart home called Resource-Oriented Service Administration (ROSA). We have implemented an application prototype, and experiments are performed to show the effectiveness of the proposed approach. The results of this research can be a foundation for realizing the vision of "end user programmable smart environments".

  7. Architecture of multicast centralized key management scheme using quantum key distribution and classical symmetric encryption

    NASA Astrophysics Data System (ADS)

    Metwaly, A. F.; Rashad, M. Z.; Omara, F. A.; Megahed, A. A.

    2014-06-01

    Multicasting refers to the transmission of a message or information from one sender to multiple receivers simultaneously. Although encryption algorithms can be used to secure transmitted messages among group members, still there are many security aspects for designing a secured multicast cryptosystem. The most important aspects of Multicasting are key generation and management. The researchers have proposed several approaches for solving problems of multicast key distribution and management. In this paper, a secure key generation and distribution solution has been proposed for a single host sending to two or more (N) receivers using centralized Quantum Multicast Key Distribution Centre "QMKDC" and classical symmetric encryption. The proposed scheme uses symmetric classical algorithms for encryption and decryption transmitted messages among multicast group members, but the generated keys which are used for authentication, encryption and decryption also play an important role for designing a secured multicast cryptosystem come from QKD protocols. Authentication verified using EPR entangled Photons and controlled-NOT gate. Multiple requests for initialization as well for transmitting sensitive information handled through priority and sensitivity levels. Multiple members' communication is achieved with full or partial support of QMKDC.

  8. [Implementation of the 5S quality control management scheme to the Ouidah hospital zone in Benin].

    PubMed

    Nana, W F; Drabo, M K; Capo Chichi, J; Agueh, V

    2015-02-01

    Delivery of quality care remains a major challenge for all heathcare institutions. The 5S quality control scheme was applied in the Ouidah hospital zone in Benin starting in 2012. The objective of the present survey was to evaluate its impact in 2013. This was a descriptive and analytic survey of the Ouidha hospital zone. Three techniques – interview, observation, review – were used to collect data from the healthcare staff, hospital users, and documents describing the strategy of the implementation. Implementation of the 5S strategy was considered, on average, to be "satisfactory" with scores of 56% for context, 61% for inputs, and 51% for processes. The internal and external users judged care delivery "very satisfactory" with a score of 79%. Although the results appear satisfactory, the future hospital policy must strengthen the quality insurance process, ensure the availability of management tools, and provide training and further motivation for the "5S" management teams. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  9. A secure and efficient chaotic map-based authenticated key agreement scheme for telecare medicine information systems.

    PubMed

    Mishra, Dheerendra; Srinivas, Jangirala; Mukhopadhyay, Sourav

    2014-10-01

    Advancement in network technology provides new ways to utilize telecare medicine information systems (TMIS) for patient care. Although TMIS usually faces various attacks as the services are provided over the public network. Recently, Jiang et al. proposed a chaotic map-based remote user authentication scheme for TMIS. Their scheme has the merits of low cost and session key agreement using Chaos theory. It enhances the security of the system by resisting various attacks. In this paper, we analyze the security of Jiang et al.'s scheme and demonstrate that their scheme is vulnerable to denial of service attack. Moreover, we demonstrate flaws in password change phase of their scheme. Further, our aim is to propose a new chaos map-based anonymous user authentication scheme for TMIS to overcome the weaknesses of Jiang et al.'s scheme, while also retaining the original merits of their scheme. We also show that our scheme is secure against various known attacks including the attacks found in Jiang et al.'s scheme. The proposed scheme is comparable in terms of the communication and computational overheads with Jiang et al.'s scheme and other related existing schemes. Moreover, we demonstrate the validity of the proposed scheme through the BAN (Burrows, Abadi, and Needham) logic.

  10. Oscillations, phase-of-firing coding, and spike timing-dependent plasticity: an efficient learning scheme.

    PubMed

    Masquelier, Timothée; Hugues, Etienne; Deco, Gustavo; Thorpe, Simon J

    2009-10-28

    Recent experiments have established that information can be encoded in the spike times of neurons relative to the phase of a background oscillation in the local field potential-a phenomenon referred to as "phase-of-firing coding" (PoFC). These firing phase preferences could result from combining an oscillation in the input current with a stimulus-dependent static component that would produce the variations in preferred phase, but it remains unclear whether these phases are an epiphenomenon or really affect neuronal interactions-only then could they have a functional role. Here we show that PoFC has a major impact on downstream learning and decoding with the now well established spike timing-dependent plasticity (STDP). To be precise, we demonstrate with simulations how a single neuron equipped with STDP robustly detects a pattern of input currents automatically encoded in the phases of a subset of its afferents, and repeating at random intervals. Remarkably, learning is possible even when only a small fraction of the afferents ( approximately 10%) exhibits PoFC. The ability of STDP to detect repeating patterns had been noted before in continuous activity, but it turns out that oscillations greatly facilitate learning. A benchmark with more conventional rate-based codes demonstrates the superiority of oscillations and PoFC for both STDP-based learning and the speed of decoding: the oscillation partially formats the input spike times, so that they mainly depend on the current input currents, and can be efficiently learned by STDP and then recognized in just one oscillation cycle. This suggests a major functional role for oscillatory brain activity that has been widely reported experimentally.

  11. Strategies for Energy Efficient Resource Management of Hybrid Programming Models

    SciTech Connect

    Li, Dong; Supinski, Bronis de; Schulz, Martin; Nikolopoulos, Dimitrios S; Cameron, Kirk W.

    2013-01-01

    Many scientific applications are programmed using hybrid programming models that use both message-passing and shared-memory, due to the increasing prevalence of large-scale systems with multicore, multisocket nodes. Previous work has shown that energy efficiency can be improved using software-controlled execution schemes that consider both the programming model and the power-aware execution capabilities of the system. However, such approaches have focused on identifying optimal resource utilization for one programming model, either shared-memory or message-passing, in isolation. The potential solution space, thus the challenge, increases substantially when optimizing hybrid models since the possible resource configurations increase exponentially. Nonetheless, with the accelerating adoption of hybrid programming models, we increasingly need improved energy efficiency in hybrid parallel applications on large-scale systems. In this work, we present new software-controlled execution schemes that consider the effects of dynamic concurrency throttling (DCT) and dynamic voltage and frequency scaling (DVFS) in the context of hybrid programming models. Specifically, we present predictive models and novel algorithms based on statistical analysis that anticipate application power and time requirements under different concurrency and frequency configurations. We apply our models and methods to the NPB MZ benchmarks and selected applications from the ASC Sequoia codes. Overall, we achieve substantial energy savings (8.74% on average and up to 13.8%) with some performance gain (up to 7.5%) or negligible performance loss.

  12. Breeding scheme and maternal small RNAs affect the efficiency of transgenerational inheritance of a paramutation in mice.

    PubMed

    Yuan, Shuiqiao; Oliver, Daniel; Schuster, Andrew; Zheng, Huili; Yan, Wei

    2015-03-18

    Paramutations result from interactions between two alleles at a single locus, whereby one induces a heritable change in the other. Although common in plants, paramutations are rarely studied in animals. Here, we report a new paramutation mouse model, in which the paramutant allele was induced by an insertional mutation and displayed the "white-tail-tip" (WTT) phenotype. The paramutation phenotype could be transmitted across multiple generations, and the breeding scheme (intercrossing vs. outcrossing) drastically affected the transmission efficiency. Paternal (i.e., sperm-borne) RNAs isolated from paramutant mice could induce the paramutation phenotype, which, however, failed to be transmitted to subsequent generations. Maternal miRNAs and piRNAs appeared to have an inhibitory effect on the efficiency of germline transmission of the paramutation. This paramutation mouse model represents an important tool for dissecting the underlying mechanism, which should be applicable to the phenomenon of epigenetic transgenerational inheritance (ETI) in general. Mechanistic insights of ETI will help us understand how organisms establish new heritable epigenetic states during development, or in times of environmental or nutritional stress.

  13. [Active management of the third stage of labor: Three schemes of oxytocin: randomised clinical trial].

    PubMed

    Neri-Mejía, M; Pedraza-Avilés, A G

    2016-05-01

    To compare the effectiveness of intramuscular oxytocin against intravenous oxytocin against intravenous traditional oxytocin infusion, in the active management of the third period of the delayed impingement labor work and controlled cord traction. Randomized controlled blinded clinical trial. In women age 14 to 40 with full term pregnancy, childbirth attended by ISSSTE's Regional Hospital "Gral. Ignacio Zaragoza", in the period from August to December 2015. 152 deliveries were attended, from which 66 fulfill with selection criteria. Group 1 = 22 patients, group 2 = 21 patients and Group 3 = 23 patients. The total age average was 26.92 + 5.8. For blood volume, statistical differences were significant among the three groups (p = 0.000). Adverse reactions were presented in 1 .5%, without difference between the groups. (P = 0.337). The differences in hemoglobin values and final and initial hematocrit presented differences with statistical significance (p = 0.000 for both). Nonetheless, the differences obtained in the analysis of the diverse variables among the three types of treatment, the three schemes are effective on the obstetrical hemorrhage prevention.

  14. A Microbial Assessment Scheme to measure microbial performance of Food Safety Management Systems.

    PubMed

    Jacxsens, L; Kussaga, J; Luning, P A; Van der Spiegel, M; Devlieghere, F; Uyttendaele, M

    2009-08-31

    A Food Safety Management System (FSMS) implemented in a food processing industry is based on Good Hygienic Practices (GHP), Hazard Analysis Critical Control Point (HACCP) principles and should address both food safety control and assurance activities in order to guarantee food safety. One of the most emerging challenges is to assess the performance of a present FSMS. The objective of this work is to explain the development of a Microbial Assessment Scheme (MAS) as a tool for a systematic analysis of microbial counts in order to assess the current microbial performance of an implemented FSMS. It is assumed that low numbers of microorganisms and small variations in microbial counts indicate an effective FSMS. The MAS is a procedure that defines the identification of critical sampling locations, the selection of microbiological parameters, the assessment of sampling frequency, the selection of sampling method and method of analysis, and finally data processing and interpretation. Based on the MAS assessment, microbial safety level profiles can be derived, indicating which microorganisms and to what extent they contribute to food safety for a specific food processing company. The MAS concept is illustrated with a case study in the pork processing industry, where ready-to-eat meat products are produced (cured, cooked ham and cured, dried bacon).

  15. Resource values in analyzing fire management programs for economic efficiency

    Treesearch

    Irene A. Althaus; Thomas J. Mills

    1982-01-01

    In analyzing fire management programs for their economic efficiency, it is necessary to assign monetary values to the changes in resource outputs caused by, fire. The derivation of resource values is complicated by imperfect or nonexistent commercial market structures. The valuation concept recommended for fire program analyses is willingness-to-pay because it permits...

  16. Planning and Management for Excellence and Efficiency in Higher Education.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    This round table discussion involved some 50 participants and seven panelists and focused on planning and management for excellence and efficiency in higher education. Basic issues or problems facing higher education were identified including coping with increasing student numbers, raising the quality of teaching, training and research programs,…

  17. Maximizing efficiency in the management of the physician practice: survival under managed care.

    PubMed

    Barker, C M

    1996-01-01

    The managed care environment is forcing physicians to maximize the efficiency of the management of their practices. Physicians can no longer afford to delegate billing and office management to inexperienced or untrained personnel. All physician practices must ensure they have resources available to maximize revenue, control expenses, and avoid costly billing errors and omissions. Use of outside resources such as practice management firms and delegation of all billing and collections to professional medical billing companies are the best alternatives available to the physician.

  18. Evaluation of Injection Efficiency of Carbon Dioxide Using an Integrated Injection Well and Geologic Formation Numerical Simulation Scheme

    NASA Astrophysics Data System (ADS)

    Kihm, J.; Park, S.; Kim, J.; SNU CO2 GEO-SEQ TEAM

    2011-12-01

    A series of integrated injection well and geologic formation numerical simulations was performed to evaluate the injection efficiency of carbon dioxide using a multiphase thermo-hydrological numerical model. The numerical simulation results show that groundwater flow, carbon dioxide flow, and heat transport in both injection well and sandstone formation can be simultaneously analyzed, and thus the injection efficiency (i.e., injection rate and injectivity) of carbon dioxide can be quantitatively evaluated using the integrated injection well and geologic formation numerical simulation scheme. The injection rate and injectivity of carbon dioxide increase rapidly during the early period of time (about 10 days) and then increase slightly up to about 2.07 kg/s (equivalent to 0.065 Mton/year) and about 2.84 × 10-7 kg/s/Pa, respectively, until 10 years for the base case. The sensitivity test results show that the injection pressure and temperature of carbon dioxide at the wellhead have significant impacts on its injection rate and injectivity. The vertical profile of the fluid pressure in the injection well becomes almost a hydrostatical equilibrium state within 1 month for all the cases. The vertical profile of the fluid temperature in the injection well becomes a monotonously increasing profile with the depth due to isenthalpic or adiabatic compression within 6 months for all the cases. The injection rate of carbon dioxide increases linearly with the fluid pressure difference between the well bottom and the sandstone formation far from the injection well. In contrast, the injectivity of carbon dioxide varies unsystematically with the fluid pressure difference. On the other hand, the reciprocal of the kinematic viscosity of carbon dioxide at the well bottom has an excellent linear relationship with the injectivity of carbon dioxide. It indicates that the above-mentioned variation of the injectivity of carbon dioxide can be corrected using this linear relationship. The

  19. The role of agri-environment schemes in conservation and environmental management

    PubMed Central

    Batáry, Péter; Dicks, Lynn V; Kleijn, David; Sutherland, William J

    2015-01-01

    Over half of the European landscape is under agricultural management and has been for millennia. Many species and ecosystems of conservation concern in Europe depend on agricultural management and are showing ongoing declines. Agri-environment schemes (AES) are designed partly to address this. They are a major source of nature conservation funding within the European Union (EU) and the highest conservation expenditure in Europe. We reviewed the structure of current AES across Europe. Since a 2003 review questioned the overall effectiveness of AES for biodiversity, there has been a plethora of case studies and meta-analyses examining their effectiveness. Most syntheses demonstrate general increases in farmland biodiversity in response to AES, with the size of the effect depending on the structure and management of the surrounding landscape. This is important in the light of successive EU enlargement and ongoing reforms of AES. We examined the change in effect size over time by merging the data sets of 3 recent meta-analyses and found that schemes implemented after revision of the EU's agri-environmental programs in 2007 were not more effective than schemes implemented before revision. Furthermore, schemes aimed at areas out of production (such as field margins and hedgerows) are more effective at enhancing species richness than those aimed at productive areas (such as arable crops or grasslands). Outstanding research questions include whether AES enhance ecosystem services, whether they are more effective in agriculturally marginal areas than in intensively farmed areas, whether they are more or less cost-effective for farmland biodiversity than protected areas, and how much their effectiveness is influenced by farmer training and advice? The general lesson from the European experience is that AES can be effective for conserving wildlife on farmland, but they are expensive and need to be carefully designed and targeted. El Papel de los Esquemas Agro-Ambientales en

  20. Integration of satellite-based energy balance with simulation models applied to irrigation management at an irrigation scheme of southern Spain

    NASA Astrophysics Data System (ADS)

    Santos, Cristina; Lorite, Ignacio J.; Tasumi, Masahiro; Allen, Richard G.; Gavilán, Pedro; Fereres, Elías

    2007-10-01

    This paper combines a water balance model with satellite-based remote-sensing estimates of evapotranspiration (ET) to provide accurate irrigation scheduling guidelines for individual fields. The satellite-derived ET was used in the daily soil water balance model to improve accuracy of field-by-field ET demands and subsequent field-scale irrigation schedules. The combination of satellite-based ET with daily soil water balance incorporates the advantages of satellite remote-sensing and daily calculation time steps, namely, high spatial resolution and high temporal resolution. The procedure was applied to Genil - Cabra Irrigation Scheme in Spain, where irrigation water supply is often limited by regional drought. Compared with traditional applications of water balance models (i.e. without the satellite-based ET), the combined procedure provided significant improvements in irrigation schedules for both the average condition and when considering field-to-field variability. A 24% reduction in water use was estimated for cotton if the improved irrigation schedules were followed. Irrigation efficiency calculated using satellite-based ET and actual applied irrigation water helped to identify specific agricultural fields experiencing problems in water management, as well as to estimate general irrigation efficiencies of the scheme by irrigation and crop type. Estimation of field irrigation efficiency ranged from 0.72 for cotton to 0.90 for sugar beet.

  1. Water management for controlling the breeding of Anopheles mosquitoes in rice irrigation schemes in Kenya.

    PubMed

    Mutero, C M; Blank, H; Konradsen, F; van der Hoek, W

    2000-10-02

    An experiment to assess the impact of intermittent irrigation on Anopheles larval populations, rice yields and water use was conducted in the Mwea rice irrigation scheme in Kenya. Four water regimes including intermittent irrigation were tested in a complete randomized block experimental design. Intermittent irrigation was carried out on a weekly schedule, with flooded conditions from Saturday through Tuesday morning. Larval sampling at each plot was conducted every Monday and prior to draining of intermittently irrigated subplots on Tuesday. All the adult anopheline mosquitoes emerging from larvae collected in the experimental plots were identified as being An. arabiensis. By far the highest numbers of An. arabiensis 1st instar larvae were found in the intermittently irrigated subplots, indicating that the water regime provided the most attractive environment for egg laying. However, the ratio between the 4th and 1st instar larvae in the subplots was only 0.08, indicating very low survival rates. In contrast, the 4th/1st instar ratio for subplots with other water management regimes ranged between 0.27 and 0.68, suggesting a correspondingly higher survival than observed with intermittent irrigation. The total number of 4th instars was almost the same in the intermittently irrigated subplots and the irrigation system normally practised by the farmers. The failure to eliminate larval development up to the 4th instar in the former method was attributed to residual pools of water. Larval abundance fluctuated throughout the 12-week sampling period. The highest larval densities were recorded in the 3 weeks after transplanting the rice seedlings. Afterwards, larval numbers dropped dramatically as the height of rice plants increased. Rice yields at harvest did not show statistically significant differences among subplots with different water regimes. The average yield per hectare ranged from 4.8-5.3 metric tonnes. The average daily water percolation/seepage rate was 3.6 mm

  2. A simple and efficient unstructured finite volume scheme for solving the shallow water equations in overland flow applications

    NASA Astrophysics Data System (ADS)

    Cea, L.; Bladé, E.

    2015-07-01

    This paper presents the decoupled hydrological discretization (DHD) scheme for solving the shallow water equations in hydrological applications involving surface runoff in rural and urban basins. The name of the scheme is motivated by the fact that the three equations which form the two-dimensional shallow water system are discretized independently from each other and thus, the numerical scheme is decoupled in a mathematical sense. Its main advantages compared to other classic finite volume schemes for the shallow water equations are its simplicity to code and the lower computational cost per time step. The validation of the scheme is presented in five test cases involving overland flow and rainfall-runoff transformation over topographies of different complexity. The scheme is compared to the finite volume scheme of Roe (1986), to the simple inertia formulation, and to the diffusive wave model. The test cases show that the DHD scheme is able to compute subcritical and supercritical flows in rural and urban environments, and that in overland flow applications it gives similar results to the second-order scheme of Roe with a lower computational cost. The results obtained with the simple inertia and diffusive wave models are very similar to those obtained with the DHD scheme in rural basins in which the bed friction and topography dominate the flow hydrodynamics but they deteriorate in typical urban configurations in which the presence of supercritical flow conditions and small-scale patterns boost the relevance of the inertial terms in the momentum equations.

  3. A directional coupling scheme for efficient coupling between Si3N4 photonic and hybrid slot-based plasmonic waveguides

    NASA Astrophysics Data System (ADS)

    Ketzaki, D.; Dabos, G.; Weeber, J. C.; Dereux, A.; Tsiokos, D.; Pleros, N.

    2017-02-01

    Slot-based plasmonic waveguides have attracted significant attention owing to their unique ability to confine light within nanometer-scale. In this context, enhanced localized light-matter interaction and control have been exploited to demonstrate novel concepts in data communication and sensing applications revealing the immense potential of plasmonic slot waveguides. However, inherent light absorption in the metallic parts included is such structures hampers the scaling of plasmonic devices and limits their application diversity. A promising solution of such issues is the use of hybrid plasmo-photonic configurations. Hybrid slot waveguides have been introduced as the means to reduce such propagation losses while maintaining their functional advantages. In addition, their co-integration with low-loss photonic waveguides can enable the development of more complex structures with acceptable overall losses. In such scenario, light needs to be efficiently transferred from the photonic to the plasmonic components and/or backwards. Based on this rationale, in this work a hybrid slot-based structure is adopted to achieve highly efficient light transfer between photonic and plasmonic slot waveguides in the near-infrared spectrum region (λ=1550 nm). This transition is realized with the aid of a directional coupling scheme. For this purpose, a Si3N4 bus waveguide (photonic branch) is located below an Aubased metallic slot (plasmonic branch) forming a hybrid waveguide element. The combined configuration, as it is shown with the aid of numerical simulations , is capable of supporting two hybrid guided modes with quasi-even and odd symmetry allowing the development of a power exchange mechanism between the two branches. In this context, a new directional coupling structure has been designed which can achieve power transmission per transition over 68% within a coupling length of the order of just several microns.

  4. Search for efficient laser resonance ionization schemes of tantalum using a newly developed time-of-flight mass-spectrometer in KISS

    NASA Astrophysics Data System (ADS)

    Mukai, M.; Hirayama, Y.; Ishiyama, H.; Jung, H. S.; Miyatake, H.; Oyaizu, M.; Watanabe, Y. X.; Kimura, S.; Ozawa, A.; Jeong, S. C.; Sonoda, T.

    2016-06-01

    The technique of laser resonance ionization is employed for an element-selective ionization of multi-nucleon transfer reaction products which are stopped and neutralized in a gas cell filled with argon gas at 50 kPa. We have been searching for efficient laser ionization schemes for refractory elements of Z = 73-78 using a time-of-flight mass-spectrometer (TOF-MS) chamber. To evaluate the isotope shift and ionization efficiency for each candidate of the ionization scheme, isotope separation using the TOF-MS was devised. The TOF-MS was designed to separate the isotopes using two-stage linear acceleration with a mass resolving power M / ΔM of >350. A mass resolving power of 250 was experimentally confirmed by measuring the TOF of laser-ionized tantalum (Z = 73) ions with mass number 181. We searched for a laser resonance ionization scheme of tantalum using the TOF-MS.

  5. Managing sustainable development conflicts: the impact of stakeholders in small-scale hydropower schemes.

    PubMed

    Watkin, Laura Jane; Kemp, Paul S; Williams, Ian D; Harwood, Ian A

    2012-06-01

    The growing importance of the environment and its management has simultaneously emphasized the benefits of hydroelectric power and its environmental costs. In a changing policy climate, giving importance to renewable energy development and environmental protection, conflict potential between stakeholders is considerable. Navigation of conflict determines the scheme constructed, making sustainable hydropower a function of human choice. To meet the needs of practitioners, greater understanding of stakeholder conflict is needed. This paper presents an approach to illustrate the challenges that face small-scale hydropower development as perceived by the stakeholders involved, and how they influence decision-making. Using Gordleton Mill, Hampshire (UK), as an illustrative case, soft systems methodology, a systems modeling approach, was adopted. Through individual interviews, a range of problems were identified and conceptually modeled. Stakeholder bias towards favoring economic appraisal over intangible social and environmental aspects was identified; costs appeared more influential than profit. Conceptual evaluation of the requirements to meet a stakeholder-approved solution suggested a complex linear systems approach, considerably different from the real-life situation. The stakeholders introduced bias to problem definition by transferring self-perceived issues onto the project owner. Application of soft systems methodology caused a shift in project goals away from further investigation towards consideration of project suitability. The challenge of sustainable hydropower is global, with a need to balance environmental, economic, and social concerns. It is clear that in this type of conflict, an individual can significantly influence outcomes; highlighting the need for more structured approaches to deal with stakeholder conflicts in sustainable hydropower development.

  6. Cost analysis of management in acute appendicitis with CT scanning under a hospital global budgeting scheme.

    PubMed

    Lin, K-H; Leung, W-S; Wang, C-P; Chen, W-K

    2008-03-01

    CT scanning of the abdomen is a highly accurate diagnostic tool for acute appendicitis. However, it is still relatively expensive in Taiwan, especially in hospitals which have adopted a global budgeting scheme. The purpose of this study was to analyse the cost of the management of this disease with and without CT scanning. A retrospective observational study was undertaken from 1 January to 30 June 2005. Patients with a working diagnosis of "acute appendicitis", "acute appendicitis should be ruled out" and "differential diagnosis including acute appendicitis" were enrolled in the study. Patient demographic data, chief complaints, working diagnoses, laboratory data, CT reports, surgical findings and costs in the emergency department (ED) and ward were collected. A total of 266 patients were admitted to an ED with symptoms suggesting acute appendicitis. Of these, 207 underwent an emergency appendectomy. An abdominal CT scan was performed in 71% of patients with a diagnosis of "differential diagnosis including acute appendicitis", which was higher than in the other two diagnostic groups (18% and 60%). Patient age, high sensitivity C-reactive protein (hsCRP) concentration, ED stay, ED expenses and hospital stay were lower in the group that did not have a CT scan than in those who did. The net cost per patient with acute appendicitis in the group who underwent CT scanning was New Taiwan dollar (NT$)40,728, which was nearly equal to the net cost per patient in the group without CT scanning (NT$39,192). Routine CT scanning in patients with possible appendicitis is not necessary. History taking and physical examination combined with laboratory tests are still useful and cost-effective methods of diagnosing acute appendicitis.

  7. Managing Sustainable Development Conflicts: The Impact of Stakeholders in Small-Scale Hydropower Schemes

    NASA Astrophysics Data System (ADS)

    Watkin, Laura Jane; Kemp, Paul S.; Williams, Ian D.; Harwood, Ian A.

    2012-06-01

    The growing importance of the environment and its management has simultaneously emphasized the benefits of hydroelectric power and its environmental costs. In a changing policy climate, giving importance to renewable energy development and environmental protection, conflict potential between stakeholders is considerable. Navigation of conflict determines the scheme constructed, making sustainable hydropower a function of human choice. To meet the needs of practitioners, greater understanding of stakeholder conflict is needed. This paper presents an approach to illustrate the challenges that face small-scale hydropower development as perceived by the stakeholders involved, and how they influence decision-making. Using Gordleton Mill, Hampshire (UK), as an illustrative case, soft systems methodology, a systems modeling approach, was adopted. Through individual interviews, a range of problems were identified and conceptually modeled. Stakeholder bias towards favoring economic appraisal over intangible social and environmental aspects was identified; costs appeared more influential than profit. Conceptual evaluation of the requirements to meet a stakeholder-approved solution suggested a complex linear systems approach, considerably different from the real-life situation. The stakeholders introduced bias to problem definition by transferring self-perceived issues onto the project owner. Application of soft systems methodology caused a shift in project goals away from further investigation towards consideration of project suitability. The challenge of sustainable hydropower is global, with a need to balance environmental, economic, and social concerns. It is clear that in this type of conflict, an individual can significantly influence outcomes; highlighting the need for more structured approaches to deal with stakeholder conflicts in sustainable hydropower development.

  8. An efficient management system for wireless sensor networks.

    PubMed

    Ma, Yi-Wei; Chen, Jiann-Liang; Huang, Yueh-Min; Lee, Mei-Yu

    2010-01-01

    Wireless sensor networks have garnered considerable attention recently. Networks typically have many sensor nodes, and are used in commercial, medical, scientific, and military applications for sensing and monitoring the physical world. Many researchers have attempted to improve wireless sensor network management efficiency. A Simple Network Management Protocol (SNMP)-based sensor network management system was developed that is a convenient and effective way for managers to monitor and control sensor network operations. This paper proposes a novel WSNManagement system that can show the connections stated of relationships among sensor nodes and can be used for monitoring, collecting, and analyzing information obtained by wireless sensor networks. The proposed network management system uses collected information for system configuration. The function of performance analysis facilitates convenient management of sensors. Experimental results show that the proposed method enhances the alive rate of an overall sensor node system, reduces the packet lost rate by roughly 5%, and reduces delay time by roughly 0.2 seconds. Performance analysis demonstrates that the proposed system is effective for wireless sensor network management.

  9. Secure and Efficient Two-Factor User Authentication Scheme with User Anonymity for Network Based E-Health Care Applications.

    PubMed

    Li, Xiong; Niu, Jianwei; Karuppiah, Marimuthu; Kumari, Saru; Wu, Fan

    2016-12-01

    Benefited from the development of network and communication technologies, E-health care systems and telemedicine have got the fast development. By using the E-health care systems, patient can enjoy the remote medical service provided by the medical server. Medical data are important privacy information for patient, so it is an important issue to ensure the secure of transmitted medical data through public network. Authentication scheme can thwart unauthorized users from accessing services via insecure network environments, so user authentication with privacy protection is an important mechanism for the security of E-health care systems. Recently, based on three factors (password, biometric and smart card), an user authentication scheme for E-health care systems was been proposed by Amin et al., and they claimed that their scheme can withstand most of common attacks. Unfortunate, we find that their scheme cannot achieve the untraceability feature of the patient. Besides, their scheme lacks a password check mechanism such that it is inefficient to find the unauthorized login by the mistake of input a wrong password. Due to the same reason, their scheme is vulnerable to Denial of Service (DoS) attack if the patient updates the password mistakenly by using a wrong password. In order improve the security level of authentication scheme for E-health care application, a robust user authentication scheme with privacy protection is proposed for E-health care systems. Then, security prove of our scheme are analysed. Security and performance analyses show that our scheme is more powerful and secure for E-health care systems when compared with other related schemes.

  10. Efficient Airframe Management Using In-Situ Structural Health Monitoring

    DTIC Science & Technology

    2012-07-01

    Efficient Airframe Management Using In-Situ Structural Health Monitoring  M. M. DERRISO , M. S. LEONARD, M. P. DESIMIO and S. E. OLSON...at predetermined times regardless of their actual conditions. This _____________ Mark M. Derriso and Matthew S. Leonard, Air Force Research...Health Monitoring Literature: 1996‐2001,” Los Alamos National Laboratory Report LA-13976-MS, February 2004. 6. Derriso , M., S. Olson, M. DeSimio, and

  11. Simulation study to assess the efficiency of a test-and-cull scheme to control the spread of the bovine viral-diarrhoea virus in a dairy herd.

    PubMed

    Viet, A-F; Fourichon, C; Seegers, H

    2006-10-17

    To control the spread of bovine viral-diarrhoea virus (BVDV), test-and-cull schemes have been used in Scandinavian countries, with success, when combined with strict control of new animal introductions into herds. In situations where BVDV reintroduction is likely to occur, it is necessary to assess precisely the expected efficiency of test-and-cull schemes. The objective of this study was to compare, by simulation, the persistence and consequences of BVDV infection in a fully susceptible dairy herd with either a test-and-cull scheme or no control action. We used a stochastic individual-based model representing the herd structure as groups of animals, herd dynamics, the contact structure within the herd and virus transmission. After an initial introduction of the virus into a fully susceptible herd, the frequency of purchases of animals that introduced the virus was simulated as high, intermediate or null. Virus persistence and epidemic size (total number of animals infected) were simulated over 10 years. The test-and-cull reduced the epidemic size and the number of days the virus was present except in herds with complete prevention of contact between groups of animals. Where no virus was reintroduced, virus persistence did not exceed 6 years with a test-and-cull scheme, whereas the virus was still present 10 years after the virus introduction in some replications with no control action (<2%). Where frequent purchases were made that led to virus introduction (6 within 10 years), with an intermediate virus transmission between groups, the probability of virus persistence 10 years after the first virus introduction fell from 31% to 8% with the test-and-cull scheme (compared to the do-nothing strategy). Within the newly infected herd, the test-and-cull scheme had no effect, on inspection, on the number of PI births, embryonic deaths or abortions over 10 years. Given this, the economic efficiency of the test-and-cull scheme should be further investigated.

  12. Challenges in provider payment under the Ghana National Health Insurance Scheme: a case study of claims management in two districts.

    PubMed

    Sodzi-Tettey, S; Aikins, M; Awoonor-Williams, J K; Agyepong, I A

    2012-12-01

    In 2004, Ghana started implementing a National Health Insurance Scheme (NHIS) to remove cost as a barrier to quality healthcare. Providers were initially paid by fee - for - service. In May 2008, this changed to paying providers by a combination of Ghana - Diagnostic Related Groupings (G-DRGs) for services and fee - for - service for medicines through the claims process. The study evaluated the claims management processes for two District MHIS in the Upper East Region of Ghana. Retrospective review of secondary claims data (2008) and a prospective observation of claims management (2009) were undertaken. Qualitative and quantitative approaches were used for primary data collection using interview guides and checklists. The reimbursements rates and value of rejected claims were calculated and compared for both districts using the z test. The null hypothesis was that no differences existed in parameters measured. Claims processes in both districts were similar and predominantly manual. There were administrative capacity, technical, human resource and working environment challenges contributing to delays in claims submission by providers and vetting and payment by schemes. Both Schemes rejected less than 1% of all claims submitted. Significant differences were observed between the Total Reimbursement Rates (TRR) and the Total Timely Reimbursement Rates (TTRR) for both schemes. For TRR, 89% and 86% were recorded for Kassena Nankana and Builsa Schemes respectively while for TTRR, 45% and 28% were recorded respectively. Ghana's NHIS needs to reform its provider payment and claims submission and processing systems to ensure simpler and faster processes. Computerization and investment to improve the capacity to administer for both purchasers and providers will be key in any reform.

  13. Spectrally efficient localized carrier distribution scheme for multiple-user DFT-S OFDM RoF- PON wireless access systems.

    PubMed

    Tao, Li; Yu, Jianjun; Yang, Qi; Luo, Ming; He, Zhixue; Shao, Yufeng; Zhang, Junwen; Chi, Nan

    2012-12-31

    We propose a modified localized carrier distribution scheme based on multi-tone generation to generate 60 GHz mm-wave for different wireless users and it improves the carrier utilization efficiency by 33.3%. The principle of multiple-user discrete Fourier transform spread optical orthogonal frequency-division multiplexing (DFT-S OFDM) Radio-over-fiber (RoF) system is presented. This multiple-user system is applicable to passive optical network (PON). Then we demonstrate a 8 x 4.65 Gb/s multiple-user DFT-S OFDM RoF-PON wireless access system over 40 km fiber link and 60 GHz wireless link using two localized carrier distribution scheme with different spectral efficiency. Compared to conventional OFDM, 2.3 dB reduction of receiver power using DFT-S OFDM modulation scheme and the calculated BER performance for 8 wireless users clearly demonstrates the feasibility of this spectrally efficient multiple-user RoF-PON scheme.

  14. Cooperative Game-Based Energy Efficiency Management over Ultra-Dense Wireless Cellular Networks.

    PubMed

    Li, Ming; Chen, Pengpeng; Gao, Shouwan

    2016-09-13

    Ultra-dense wireless cellular networks have been envisioned as a promising technique for handling the explosive increase of wireless traffic volume. With the extensive deployment of small cells in wireless cellular networks, the network spectral efficiency (SE) is improved with the use of limited frequency. However, the mutual inter-tier and intra-tier interference between or among small cells and macro cells becomes serious. On the other hand, more chances for potential cooperation among different cells are introduced. Energy efficiency (EE) has become one of the most important problems for future wireless networks. This paper proposes a cooperative bargaining game-based method for comprehensive EE management in an ultra-dense wireless cellular network, which highlights the complicated interference influence on energy-saving challenges and the power-coordination process among small cells and macro cells. Especially, a unified EE utility with the consideration of the interference mitigation is proposed to jointly address the SE, the deployment efficiency (DE), and the EE. In particular, closed-form power-coordination solutions for the optimal EE are derived to show the convergence property of the algorithm. Moreover, a simplified algorithm is presented to reduce the complexity of the signaling overhead, which is significant for ultra-dense small cells. Finally, numerical simulations are provided to illustrate the efficiency of the proposed cooperative bargaining game-based and simplified schemes.

  15. Cooperative Game-Based Energy Efficiency Management over Ultra-Dense Wireless Cellular Networks

    PubMed Central

    Li, Ming; Chen, Pengpeng; Gao, Shouwan

    2016-01-01

    Ultra-dense wireless cellular networks have been envisioned as a promising technique for handling the explosive increase of wireless traffic volume. With the extensive deployment of small cells in wireless cellular networks, the network spectral efficiency (SE) is improved with the use of limited frequency. However, the mutual inter-tier and intra-tier interference between or among small cells and macro cells becomes serious. On the other hand, more chances for potential cooperation among different cells are introduced. Energy efficiency (EE) has become one of the most important problems for future wireless networks. This paper proposes a cooperative bargaining game-based method for comprehensive EE management in an ultra-dense wireless cellular network, which highlights the complicated interference influence on energy-saving challenges and the power-coordination process among small cells and macro cells. Especially, a unified EE utility with the consideration of the interference mitigation is proposed to jointly address the SE, the deployment efficiency (DE), and the EE. In particular, closed-form power-coordination solutions for the optimal EE are derived to show the convergence property of the algorithm. Moreover, a simplified algorithm is presented to reduce the complexity of the signaling overhead, which is significant for ultra-dense small cells. Finally, numerical simulations are provided to illustrate the efficiency of the proposed cooperative bargaining game-based and simplified schemes. PMID:27649170

  16. Clinical information systems: cornerstone for an efficient hospital management.

    PubMed

    Lovis, Christian

    2011-01-01

    The university hospitals of Geneva are the largest consortium of public hospitals in Switzerland. This organization is born in 1995, after a political decision to merge the seven public and teaching hospitals of the Canton of Geneva. From an information technologies perspective, it took several years to reach a true unified vision of the complete organization. The clinical information system is deployed in all sites covering in- and outpatient cares. It is seen as the cornerstone of information management and flow in the organization, for direct patient care and decision support, but also for the management to drive, improve and leverage the activities, for better efficiency, quality and safety of care, but also to drive processes. As the system has become more important for the organization, it has required progressive changes in its governance. The high importance of interoperability and use of formal representation has become a major challenge in order to be able to reuse clinical information for real-time care and management activities, and for secondary usage such as billing, resource management, strategic planning and clinical research. This paper proposes a short overview of the tools allowing to leverage the management for physicians, nurses, human resources and hospital governance.

  17. Very Efficient High-order Hyperbolic Schemes for Time-dependent Advection Diffusion Problems: Third-, Fourth-, and Sixth-order

    DTIC Science & Technology

    2014-07-07

    discretization. In this paper, two techniques for the source term discretization are proposed; (1) reformulation of the source terms with their divergence...modifying the source term discretization. In this paper, two techniques for the source term discretization are proposed; (1) reformulation of the...and fourth-order schemes from the former technique . These schemes require computations of the gradients and second-derivatives of the source terms

  18. Don’t make cache too complex: A simple probability-based cache management scheme for SSDs

    PubMed Central

    Cho, Sangyeun; Choi, Jongmoo

    2017-01-01

    Solid-state drives (SSDs) have recently become a common storage component in computer systems, and they are fueled by continued bit cost reductions achieved with smaller feature sizes and multiple-level cell technologies. However, as the flash memory stores more bits per cell, the performance and reliability of the flash memory degrade substantially. To solve this problem, a fast non-volatile memory (NVM-)based cache has been employed within SSDs to reduce the long latency required to write data. Absorbing small writes in a fast NVM cache can also reduce the number of flash memory erase operations. To maximize the benefits of an NVM cache, it is important to increase the NVM cache utilization. In this paper, we propose and study ProCache, a simple NVM cache management scheme, that makes cache-entrance decisions based on random probability testing. Our scheme is motivated by the observation that frequently written hot data will eventually enter the cache with a high probability, and that infrequently accessed cold data will not enter the cache easily. Owing to its simplicity, ProCache is easy to implement at a substantially smaller cost than similar previously studied techniques. We evaluate ProCache and conclude that it achieves comparable performance compared to a more complex reference counter-based cache-management scheme. PMID:28358897

  19. Don't make cache too complex: A simple probability-based cache management scheme for SSDs.

    PubMed

    Baek, Seungjae; Cho, Sangyeun; Choi, Jongmoo

    2017-01-01

    Solid-state drives (SSDs) have recently become a common storage component in computer systems, and they are fueled by continued bit cost reductions achieved with smaller feature sizes and multiple-level cell technologies. However, as the flash memory stores more bits per cell, the performance and reliability of the flash memory degrade substantially. To solve this problem, a fast non-volatile memory (NVM-)based cache has been employed within SSDs to reduce the long latency required to write data. Absorbing small writes in a fast NVM cache can also reduce the number of flash memory erase operations. To maximize the benefits of an NVM cache, it is important to increase the NVM cache utilization. In this paper, we propose and study ProCache, a simple NVM cache management scheme, that makes cache-entrance decisions based on random probability testing. Our scheme is motivated by the observation that frequently written hot data will eventually enter the cache with a high probability, and that infrequently accessed cold data will not enter the cache easily. Owing to its simplicity, ProCache is easy to implement at a substantially smaller cost than similar previously studied techniques. We evaluate ProCache and conclude that it achieves comparable performance compared to a more complex reference counter-based cache-management scheme.

  20. The impact of instructing management skill to managers on the obstetrician's efficiency.

    PubMed

    Maleki, B; Rahimikian, F; Salehi, T; Mehran, A

    2015-01-01

    The importance of efficiency and improvement of health service for resolving people's health requirement and meeting their expectation is increasing. In addition, it considers as a priority for making decision and manager's activity in health officials. Manager's control on the management principle and the proper use of their management skill and creating a sense of trust and commitment are the tools that were providing a good condition for working and catching the organization's goals. In this quasi-experimental study, before beginning the research, the non-teaching hospitals that are affiliated to the Kurdistan's medical science university were randomly divided into 2 groups. Three hospitals from 3 cities considered as a control group, and three hospitals from 3 cities considered as an intervention group.80 person of hospital's obstetrician staff classified in these 2 group by quota method and the hospital's nurses and obstetrician's manager of case-control involved by census method. The research's tool was Hersi and Gold Smith's standard efficiency questionnaire, which was filled out at the beginning of the study by the obstetricians of both groups and then it gave to the hospital's nurses and obstetrician's managers of the case group's instructing management skills for 16 hours. The efficiency's questionnaire was filled out, compared, and evaluated again by the obstetricians of both groups, 12 weeks after intervention. The data analyzed by the independent T-test, variance analysis, paired T-test, and SPSS 22. The findings showed that the average of the obstetrician's efficiency mainly developed in the intervention team after the instruction of management skills to the managers (P < 0.001).

  1. Efficient Management of Complex Striped Files in Active Storage

    SciTech Connect

    Piernas Canovas, Juan; Nieplocha, Jaroslaw

    2008-08-25

    Active Storage provides an opportunity for reducing the band- width requirements between the storage and compute elements of cur- rent supercomputing systems, and leveraging the processing power of the storage nodes used by some modern file systems. To achieve both objec- tives, Active Storage allows certain processing tasks to be performed directly on the storage nodes, near the data they manage. However, Active Storage must also support key requirements of scientific applications. In particular, Active Storage must be able to support striped files and files with complex formats (e.g., netCDF). In this paper, we describe how these important requirements can be addressed. The experimental results on a Lustre file system not only show that our proposal can re- duce the network traffic to near zero and scale the performance with the number of storage nodes, but also that it provides an efficient treatment of striped files and can manage files with complex data structures.

  2. Efficient and effective compound management to support lead optimization.

    PubMed

    Johnson, Chad W; Chatterjee, Moneesh; Kubala, Steve; Helm, David; Houston, John; Banks, Martyn

    2009-06-01

    The introduction of lean thinking and Six Sigma methodologies into the drug discovery process has become an important approach for ensuring efficient workflows while containing costs. For the compound management department at Bristol-Myers Squibb, this has resulted in a partnership with the research community to evaluate and streamline processes to enable cost-disciplined science. The authors describe the results of Lean Six Sigma approaches in the automation and informatics environment that have been optimized to support parallel processing of compounds. This new platform facilitates the rapid and simultaneous data generation from structure activity and structure liability assays. As a result of these compound management improvements, reduction of timelines and quicker decision making has been achieved in the lead optimization process.

  3. Dynamic Ocean Management Increases the Efficiency and Efficacy of Fisheries Management

    NASA Astrophysics Data System (ADS)

    Dunn, D. C.; Maxwell, S.; Boustany, A. M.; Halpin, P. N.

    2016-02-01

    In response to the inherent dynamic nature of the oceans and continuing difficulty in managing ecosystem impacts of fisheries, interest in the concept of dynamic ocean management, or real-time management of ocean resources, has accelerated in the last several years. However, scientists have yet to quantitatively assess the efficiency of dynamic management over static management. Of particular interest is how scale influences effectiveness, both in terms of how it reflects underlying ecological processes and how this relates to potential efficiency gains. In this presentation, we attempt to address both the empirical evidence gap and further the ecological theory underpinning dynamic management. We illustrate, through the simulation of closures across a range of spatiotemporal scales, that dynamic ocean management can address previously intractable problems at scales associated with coactive and social patterns (e.g., competition, predation, niche partitioning, parasitism and social aggregations). Further, it can significantly improve the efficiency of management: as the resolution of the individual closures used increases (i.e., as the closures become more targeted) the percent of target catch forgone or displaced decreases, the reduction ratio (bycatch/catch) increases, and the total time-area required to achieve the desired bycatch reduction decreases. The coarser management measures (annual time-area closures and monthly full fishery closures) affected up to 4-5x the target catch and required 100-200x the time-area of the dynamic measures (grid-based closures and move-on rules). To achieve similar reductions in juvenile bycatch, the fishery would forgo or displace between USD 15-52 million in landings using a static approach over a dynamic management approach.

  4. Dynamic Ocean Management Increases the Efficiency and Efficacy of Fisheries Management

    NASA Astrophysics Data System (ADS)

    Dunn, D. C.; Maxwell, S.; Boustany, A. M.; Halpin, P. N.

    2016-12-01

    In response to the inherent dynamic nature of the oceans and continuing difficulty in managing ecosystem impacts of fisheries, interest in the concept of dynamic ocean management, or real-time management of ocean resources, has accelerated in the last several years. However, scientists have yet to quantitatively assess the efficiency of dynamic management over static management. Of particular interest is how scale influences effectiveness, both in terms of how it reflects underlying ecological processes and how this relates to potential efficiency gains. In this presentation, we attempt to address both the empirical evidence gap and further the ecological theory underpinning dynamic management. We illustrate, through the simulation of closures across a range of spatiotemporal scales, that dynamic ocean management can address previously intractable problems at scales associated with coactive and social patterns (e.g., competition, predation, niche partitioning, parasitism and social aggregations). Further, it can significantly improve the efficiency of management: as the resolution of the individual closures used increases (i.e., as the closures become more targeted) the percent of target catch forgone or displaced decreases, the reduction ratio (bycatch/catch) increases, and the total time-area required to achieve the desired bycatch reduction decreases. The coarser management measures (annual time-area closures and monthly full fishery closures) affected up to 4-5x the target catch and required 100-200x the time-area of the dynamic measures (grid-based closures and move-on rules). To achieve similar reductions in juvenile bycatch, the fishery would forgo or displace between USD 15-52 million in landings using a static approach over a dynamic management approach.

  5. Dynamic ocean management increases the efficiency and efficacy of fisheries management.

    PubMed

    Dunn, Daniel C; Maxwell, Sara M; Boustany, Andre M; Halpin, Patrick N

    2016-01-19

    In response to the inherent dynamic nature of the oceans and continuing difficulty in managing ecosystem impacts of fisheries, interest in the concept of dynamic ocean management, or real-time management of ocean resources, has accelerated in the last several years. However, scientists have yet to quantitatively assess the efficiency of dynamic management over static management. Of particular interest is how scale influences effectiveness, both in terms of how it reflects underlying ecological processes and how this relates to potential efficiency gains. Here, we address the empirical evidence gap and further the ecological theory underpinning dynamic management. We illustrate, through the simulation of closures across a range of spatiotemporal scales, that dynamic ocean management can address previously intractable problems at scales associated with coactive and social patterns (e.g., competition, predation, niche partitioning, parasitism, and social aggregations). Furthermore, it can significantly improve the efficiency of management: as the resolution of the closures used increases (i.e., as the closures become more targeted), the percentage of target catch forgone or displaced decreases, the reduction ratio (bycatch/catch) increases, and the total time-area required to achieve the desired bycatch reduction decreases. In the scenario examined, coarser scale management measures (annual time-area closures and monthly full-fishery closures) would displace up to four to five times the target catch and require 100-200 times more square kilometer-days of closure than dynamic measures (grid-based closures and move-on rules). To achieve similar reductions in juvenile bycatch, the fishery would forgo or displace between USD 15-52 million in landings using a static approach over a dynamic management approach.

  6. Dynamic ocean management increases the efficiency and efficacy of fisheries management

    PubMed Central

    Maxwell, Sara M.; Halpin, Patrick N.

    2016-01-01

    In response to the inherent dynamic nature of the oceans and continuing difficulty in managing ecosystem impacts of fisheries, interest in the concept of dynamic ocean management, or real-time management of ocean resources, has accelerated in the last several years. However, scientists have yet to quantitatively assess the efficiency of dynamic management over static management. Of particular interest is how scale influences effectiveness, both in terms of how it reflects underlying ecological processes and how this relates to potential efficiency gains. Here, we address the empirical evidence gap and further the ecological theory underpinning dynamic management. We illustrate, through the simulation of closures across a range of spatiotemporal scales, that dynamic ocean management can address previously intractable problems at scales associated with coactive and social patterns (e.g., competition, predation, niche partitioning, parasitism, and social aggregations). Furthermore, it can significantly improve the efficiency of management: as the resolution of the closures used increases (i.e., as the closures become more targeted), the percentage of target catch forgone or displaced decreases, the reduction ratio (bycatch/catch) increases, and the total time–area required to achieve the desired bycatch reduction decreases. In the scenario examined, coarser scale management measures (annual time–area closures and monthly full-fishery closures) would displace up to four to five times the target catch and require 100–200 times more square kilometer-days of closure than dynamic measures (grid-based closures and move-on rules). To achieve similar reductions in juvenile bycatch, the fishery would forgo or displace between USD 15–52 million in landings using a static approach over a dynamic management approach. PMID:26729885

  7. The Blood Stocks Management Scheme, a partnership venture between the National Blood Service of England and North Wales and participating hospitals for maximizing blood supply chain management.

    PubMed

    Chapman, J F; Cook, R

    2002-10-01

    The Blood Stocks Management Scheme (BSMS) has been established as a joint venture between the National Blood Service (NBS) in England and North Wales and participating hospitals to monitor the blood supply chain. Stock and wastage data are submitted to a web-based data-management system, facilitating continuous and complete red cell data collection and 'real time' data extraction. The data-management system enables peer review of performance in respect of stock holding levels and red cell wastage. The BSMS has developed an innovative web-based data-management system that enables data collection and benchmarking of practice, which should drive changes in stock management practice, therefore optimizing the use of donated blood.

  8. An efficient high-order compact scheme for the unsteady compressible Euler and Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Lerat, A.

    2016-10-01

    Residual-Based Compact (RBC) schemes approximate the 3-D compressible Euler equations with a 5th- or 7th-order accuracy on a 5 × 5 × 5-point stencil and capture shocks pretty well without correction. For unsteady flows however, they require a costly algebra to extract the time-derivative occurring at several places in the scheme. A new high-order time formulation has been recently proposed [13] for simplifying the RBC schemes and increasing their temporal accuracy. The present paper goes much further in this direction and deeply reconsiders the method. An avatar of the RBC schemes is presented that greatly reduces the computing time and the memory requirements while keeping the same type of successful numerical dissipation. Two and three-dimensional linear stability are analyzed and the method is extended to the 3-D compressible Navier-Stokes equations. The new compact scheme is validated for several unsteady problems in two and three dimension. In particular, an accurate DNS at moderate cost is presented for the evolution of the Taylor-Green Vortex at Reynolds 1600 and Prandtl 0.71. The effects of the mesh size and of the accuracy order in the approximation of Euler and viscous terms are discussed.

  9. A memory efficient implementation scheme of Gauss error function in a Laguerre-Volterra network for neuroprosthetic devices

    NASA Astrophysics Data System (ADS)

    Li, Will X. Y.; Cui, Ke; Zhang, Wei

    2017-04-01

    Cognitive neural prosthesis is a manmade device which can be used to restore or compensate for lost human cognitive modalities. The generalized Laguerre-Volterra (GLV) network serves as a robust mathematical underpinning for the development of such prosthetic instrument. In this paper, a hardware implementation scheme of Gauss error function for the GLV network targeting reconfigurable platforms is reported. Numerical approximations are formulated which transform the computation of nonelementary function into combinational operations of elementary functions, and memory-intensive look-up table (LUT) based approaches can therefore be circumvented. The computational precision can be made adjustable with the utilization of an error compensation scheme, which is proposed based on the experimental observation of the mathematical characteristics of the error trajectory. The precision can be further customizable by exploiting the run-time characteristics of the reconfigurable system. Compared to the polynomial expansion based implementation scheme, the utilization of slice LUTs, occupied slices, and DSP48E1s on a Xilinx XC6VLX240T field-programmable gate array has decreased by 94.2%, 94.1%, and 90.0%, respectively. While compared to the look-up table based scheme, 1.0 ×1017 bits of storage can be spared under the maximum allowable error of 1.0 ×10-3 . The proposed implementation scheme can be employed in the study of large-scale neural ensemble activity and in the design and development of neural prosthetic device.

  10. A memory efficient implementation scheme of Gauss error function in a Laguerre-Volterra network for neuroprosthetic devices.

    PubMed

    Li, Will X Y; Cui, Ke; Zhang, Wei

    2017-04-01

    Cognitive neural prosthesis is a manmade device which can be used to restore or compensate for lost human cognitive modalities. The generalized Laguerre-Volterra (GLV) network serves as a robust mathematical underpinning for the development of such prosthetic instrument. In this paper, a hardware implementation scheme of Gauss error function for the GLV network targeting reconfigurable platforms is reported. Numerical approximations are formulated which transform the computation of nonelementary function into combinational operations of elementary functions, and memory-intensive look-up table (LUT) based approaches can therefore be circumvented. The computational precision can be made adjustable with the utilization of an error compensation scheme, which is proposed based on the experimental observation of the mathematical characteristics of the error trajectory. The precision can be further customizable by exploiting the run-time characteristics of the reconfigurable system. Compared to the polynomial expansion based implementation scheme, the utilization of slice LUTs, occupied slices, and DSP48E1s on a Xilinx XC6VLX240T field-programmable gate array has decreased by 94.2%, 94.1%, and 90.0%, respectively. While compared to the look-up table based scheme, 1.0×10(17) bits of storage can be spared under the maximum allowable error of 1.0×10(-3). The proposed implementation scheme can be employed in the study of large-scale neural ensemble activity and in the design and development of neural prosthetic device.

  11. Significance of symmetry in the nuclear spin Hamiltonian for efficient heteronuclear dipolar decoupling in solid-state NMR: A Floquet description of supercycled rCW schemes.

    PubMed

    Equbal, Asif; Shankar, Ravi; Leskes, Michal; Vega, Shimon; Nielsen, Niels Chr; Madhu, P K

    2017-03-14

    Symmetry plays an important role in the retention or annihilation of a desired interaction Hamiltonian in NMR experiments. Here, we explore the role of symmetry in the radio-frequency interaction frame Hamiltonian of the refocused-continuous-wave (rCW) pulse scheme that leads to efficient (1)H heteronuclear decoupling in solid-state NMR. It is demonstrated that anti-periodic symmetry of single-spin operators (Ix, Iy, Iz) in the interaction frame can lead to complete annihilation of the (1)H-(1)H homonuclear dipolar coupling effects that induce line broadening in solid-state NMR experiments. This symmetry also plays a critical role in cancelling or minimizing the effect of (1)H chemical-shift anisotropy in the effective Hamiltonian. An analytical description based on Floquet theory is presented here along with experimental evidences to understand the decoupling efficiency of supercycled (concatenated) rCW scheme.

  12. Significance of symmetry in the nuclear spin Hamiltonian for efficient heteronuclear dipolar decoupling in solid-state NMR: A Floquet description of supercycled rCW schemes

    NASA Astrophysics Data System (ADS)

    Equbal, Asif; Shankar, Ravi; Leskes, Michal; Vega, Shimon; Nielsen, Niels Chr.; Madhu, P. K.

    2017-03-01

    Symmetry plays an important role in the retention or annihilation of a desired interaction Hamiltonian in NMR experiments. Here, we explore the role of symmetry in the radio-frequency interaction frame Hamiltonian of the refocused-continuous-wave (rCW) pulse scheme that leads to efficient 1H heteronuclear decoupling in solid-state NMR. It is demonstrated that anti-periodic symmetry of single-spin operators (Ix, Iy, Iz) in the interaction frame can lead to complete annihilation of the 1H-1H homonuclear dipolar coupling effects that induce line broadening in solid-state NMR experiments. This symmetry also plays a critical role in cancelling or minimizing the effect of 1H chemical-shift anisotropy in the effective Hamiltonian. An analytical description based on Floquet theory is presented here along with experimental evidences to understand the decoupling efficiency of supercycled (concatenated) rCW scheme.

  13. EM modelling of arbitrary shaped anisotropic dielectric objects using an efficient 3D leapfrog scheme on unstructured meshes

    NASA Astrophysics Data System (ADS)

    Gansen, A.; Hachemi, M. El; Belouettar, S.; Hassan, O.; Morgan, K.

    2016-09-01

    The standard Yee algorithm is widely used in computational electromagnetics because of its simplicity and divergence free nature. A generalization of the classical Yee scheme to 3D unstructured meshes is adopted, based on the use of a Delaunay primal mesh and its high quality Voronoi dual. This allows the problem of accuracy losses, which are normally associated with the use of the standard Yee scheme and a staircased representation of curved material interfaces, to be circumvented. The 3D dual mesh leapfrog-scheme which is presented has the ability to model both electric and magnetic anisotropic lossy materials. This approach enables the modelling of problems, of current practical interest, involving structured composites and metamaterials.

  14. BlueDetect: An iBeacon-Enabled Scheme for Accurate and Energy-Efficient Indoor-Outdoor Detection and Seamless Location-Based Service.

    PubMed

    Zou, Han; Jiang, Hao; Luo, Yiwen; Zhu, Jianjie; Lu, Xiaoxuan; Xie, Lihua

    2016-02-22

    The location and contextual status (indoor or outdoor) is fundamental and critical information for upper-layer applications, such as activity recognition and location-based services (LBS) for individuals. In addition, optimizations of building management systems (BMS), such as the pre-cooling or heating process of the air-conditioning system according to the human traffic entering or exiting a building, can utilize the information, as well. The emerging mobile devices, which are equipped with various sensors, become a feasible and flexible platform to perform indoor-outdoor (IO) detection. However, power-hungry sensors, such as GPS and WiFi, should be used with caution due to the constrained battery storage on mobile device. We propose BlueDetect: an accurate, fast response and energy-efficient scheme for IO detection and seamless LBS running on the mobile device based on the emerging low-power iBeacon technology. By leveraging the on-broad Bluetooth module and our proposed algorithms, BlueDetect provides a precise IO detection service that can turn on/off on-board power-hungry sensors smartly and automatically, optimize their performances and reduce the power consumption of mobile devices simultaneously. Moreover, seamless positioning and navigation services can be realized by it, especially in a semi-outdoor environment, which cannot be achieved by GPS or an indoor positioning system (IPS) easily. We prototype BlueDetect on Android mobile devices and evaluate its performance comprehensively. The experimental results have validated the superiority of BlueDetect in terms of IO detection accuracy, localization accuracy and energy consumption.

  15. BlueDetect: An iBeacon-Enabled Scheme for Accurate and Energy-Efficient Indoor-Outdoor Detection and Seamless Location-Based Service

    PubMed Central

    Zou, Han; Jiang, Hao; Luo, Yiwen; Zhu, Jianjie; Lu, Xiaoxuan; Xie, Lihua

    2016-01-01

    The location and contextual status (indoor or outdoor) is fundamental and critical information for upper-layer applications, such as activity recognition and location-based services (LBS) for individuals. In addition, optimizations of building management systems (BMS), such as the pre-cooling or heating process of the air-conditioning system according to the human traffic entering or exiting a building, can utilize the information, as well. The emerging mobile devices, which are equipped with various sensors, become a feasible and flexible platform to perform indoor-outdoor (IO) detection. However, power-hungry sensors, such as GPS and WiFi, should be used with caution due to the constrained battery storage on mobile device. We propose BlueDetect: an accurate, fast response and energy-efficient scheme for IO detection and seamless LBS running on the mobile device based on the emerging low-power iBeacon technology. By leveraging the on-broad Bluetooth module and our proposed algorithms, BlueDetect provides a precise IO detection service that can turn on/off on-board power-hungry sensors smartly and automatically, optimize their performances and reduce the power consumption of mobile devices simultaneously. Moreover, seamless positioning and navigation services can be realized by it, especially in a semi-outdoor environment, which cannot be achieved by GPS or an indoor positioning system (IPS) easily. We prototype BlueDetect on Android mobile devices and evaluate its performance comprehensively. The experimental results have validated the superiority of BlueDetect in terms of IO detection accuracy, localization accuracy and energy consumption. PMID:26907295

  16. Distributed mixed-integer fuzzy hierarchical programming for municipal solid waste management. Part II: scheme analysis and mechanism revelation.

    PubMed

    Cheng, Guanhui; Huang, Guohe; Dong, Cong; Xu, Ye; Chen, Jiapei; Chen, Xiujuan; Li, Kailong

    2017-02-16

    As presented in the first companion paper, distributed mixed-integer fuzzy hierarchical programming (DMIFHP) was developed for municipal solid waste management (MSWM) under complexities of heterogeneities, hierarchy, discreteness, and interactions. Beijing was selected as a representative case. This paper focuses on presenting the obtained schemes and the revealed mechanisms of the Beijing MSWM system. The optimal MSWM schemes for Beijing under various solid waste treatment policies and their differences are deliberated. The impacts of facility expansion, hierarchy, and spatial heterogeneities and potential extensions of DMIFHP are also discussed. A few of findings are revealed from the results and a series of comparisons and analyses. For instance, DMIFHP is capable of robustly reflecting these complexities in MSWM systems, especially for Beijing. The optimal MSWM schemes are of fragmented patterns due to the dominant role of the proximity principle in allocating solid waste treatment resources, and they are closely related to regulated ratios of landfilling, incineration, and composting. Communities without significant differences among distances to different types of treatment facilities are more sensitive to these ratios than others. The complexities of hierarchy and heterogeneities pose significant impacts on MSWM practices. Spatial dislocation of MSW generation rates and facility capacities caused by unreasonable planning in the past may result in insufficient utilization of treatment capacities under substantial influences of transportation costs. The problems of unreasonable MSWM planning, e.g., severe imbalance among different technologies and complete vacancy of ten facilities, should be gained deliberation of the public and the municipal or local governments in Beijing. These findings are helpful for gaining insights into MSWM systems under these complexities, mitigating key challenges in the planning of these systems, improving the related management

  17. Multi-criteria decision aid approach for the selection of the best compromise management scheme for ELVs: the case of Cyprus.

    PubMed

    Mergias, I; Moustakas, K; Papadopoulos, A; Loizidou, M

    2007-08-25

    Each alternative scheme for treating a vehicle at its end of life has its own consequences from a social, environmental, economic and technical point of view. Furthermore, the criteria used to determine these consequences are often contradictory and not equally important. In the presence of multiple conflicting criteria, an optimal alternative scheme never exists. A multiple-criteria decision aid (MCDA) method to aid the Decision Maker (DM) in selecting the best compromise scheme for the management of End-of-Life Vehicles (ELVs) is presented in this paper. The constitution of a set of alternatives schemes, the selection of a list of relevant criteria to evaluate these alternative schemes and the choice of an appropriate management system are also analyzed in this framework. The proposed procedure relies on the PROMETHEE method which belongs to the well-known family of multiple criteria outranking methods. For this purpose, level, linear and Gaussian functions are used as preference functions.

  18. Brillouin-zone integration schemes: an efficiency study for the phonon frequency moments of the harmonic, solid, one-component plasma

    SciTech Connect

    Albers, R.C.; Gubernatis, J.E.

    1981-01-01

    The efficiency of four different Brillouin-zone integration schemes including the uniform mesh, special point method, special directions method, and Holas method are compared for calculating moments of the harmonic phonon frequencies of the solid one-component plasma. Very accurate values for the moments are also presented. The Holas method for which weights and integration points can easily be generated has roughly the same efficiency as the special directions method, which is much superior to the uniform mesh and special point methods for this problem.

  19. Efficient Mobility Management Signalling in Network Mobility Supported PMIPV6

    PubMed Central

    Jebaseeli Samuelraj, Ananthi; Jayapal, Sundararajan

    2015-01-01

    Proxy Mobile IPV6 (PMIPV6) is a network based mobility management protocol which supports node's mobility without the contribution from the respective mobile node. PMIPV6 is initially designed to support individual node mobility and it should be enhanced to support mobile network movement. NEMO-BSP is an existing protocol to support network mobility (NEMO) in PMIPV6 network. Due to the underlying differences in basic protocols, NEMO-BSP cannot be directly applied to PMIPV6 network. Mobility management signaling and data structures used for individual node's mobility should be modified to support group nodes' mobility management efficiently. Though a lot of research work is in progress to implement mobile network movement in PMIPV6, it is not yet standardized and each suffers with different shortcomings. This research work proposes modifications in NEMO-BSP and PMIPV6 to achieve NEMO support in PMIPV6. It mainly concentrates on optimizing the number and size of mobility signaling exchanged while mobile network or mobile network node changes its access point. PMID:26366431

  20. Efficient Mobility Management Signalling in Network Mobility Supported PMIPV6.

    PubMed

    Samuelraj, Ananthi Jebaseeli; Jayapal, Sundararajan

    2015-01-01

    Proxy Mobile IPV6 (PMIPV6) is a network based mobility management protocol which supports node's mobility without the contribution from the respective mobile node. PMIPV6 is initially designed to support individual node mobility and it should be enhanced to support mobile network movement. NEMO-BSP is an existing protocol to support network mobility (NEMO) in PMIPV6 network. Due to the underlying differences in basic protocols, NEMO-BSP cannot be directly applied to PMIPV6 network. Mobility management signaling and data structures used for individual node's mobility should be modified to support group nodes' mobility management efficiently. Though a lot of research work is in progress to implement mobile network movement in PMIPV6, it is not yet standardized and each suffers with different shortcomings. This research work proposes modifications in NEMO-BSP and PMIPV6 to achieve NEMO support in PMIPV6. It mainly concentrates on optimizing the number and size of mobility signaling exchanged while mobile network or mobile network node changes its access point.

  1. An efficient finite-difference scheme for computation of electron states in free-standing and core-shell quantum wires

    NASA Astrophysics Data System (ADS)

    Arsoski, V. V.; Čukarić, N. A.; Tadić, M. Ž.; Peeters, F. M.

    2015-12-01

    The electron states in axially symmetric quantum wires are computed by means of the effective-mass Schrödinger equation, which is written in cylindrical coordinates φ, ρ, and z. We show that a direct discretization of the Schrödinger equation by central finite differences leads to a non-symmetric Hamiltonian matrix. Because diagonalization of such matrices is more complex it is advantageous to transform it in a symmetric form. This can be done by the Liouville-like transformation proposed by Rizea et al. (2008), which replaces the wave function ψ(ρ) with the function F(ρ) = ψ(ρ) √{ ρ } and transforms the Hamiltonian accordingly. Even though a symmetric Hamiltonian matrix is produced by this procedure, the computed wave functions are found to be inaccurate near the origin, and the accuracy of the energy levels is not very high. In order to improve on this, we devised a finite-difference scheme which discretizes the Schrödinger equation in the first step, and then applies the Liouville-like transformation to the difference equation. Such a procedure gives a symmetric Hamiltonian matrix, resulting in an accuracy comparable to the one obtained with the finite element method. The superior efficiency of the new finite-difference scheme (FDM) is demonstrated for a few ρ-dependent one-dimensional potentials which are usually employed to model the electron states in free-standing and core-shell quantum wires. The new scheme is compared with the other FDM schemes for solving the effective-mass Schrödinger equation, and is found to deliver energy levels with much smaller numerical error for all the analyzed potentials. It also gives more accurate results than the scheme of Rizea et al., except for the ground state of an infinite rectangular potential in freestanding quantum wires. Moreover, the PT symmetry is invoked to explain similarities and differences between the considered FDM schemes.

  2. Efficiency and Flexibility of Fingerprint Scheme Using Partial Encryption and Discrete Wavelet Transform to Verify User in Cloud Computing

    PubMed Central

    Yassin, Ali A.

    2014-01-01

    Now, the security of digital images is considered more and more essential and fingerprint plays the main role in the world of image. Furthermore, fingerprint recognition is a scheme of biometric verification that applies pattern recognition techniques depending on image of fingerprint individually. In the cloud environment, an adversary has the ability to intercept information and must be secured from eavesdroppers. Unluckily, encryption and decryption functions are slow and they are often hard. Fingerprint techniques required extra hardware and software; it is masqueraded by artificial gummy fingers (spoof attacks). Additionally, when a large number of users are being verified at the same time, the mechanism will become slow. In this paper, we employed each of the partial encryptions of user's fingerprint and discrete wavelet transform to obtain a new scheme of fingerprint verification. Moreover, our proposed scheme can overcome those problems; it does not require cost, reduces the computational supplies for huge volumes of fingerprint images, and resists well-known attacks. In addition, experimental results illustrate that our proposed scheme has a good performance of user's fingerprint verification. PMID:27355051

  3. A computationally efficient scheme for the inversion of large scale potential field data: Application to synthetic and real data

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Meng, Xiaohong; Li, Fang

    2015-12-01

    Three dimensional (3D) inversion of potential field data from large scale surveys attempts to recover density or magnetic susceptibility distribution in the subspace for geological interpretation. It is computationally challenging and is not feasible on desktop computers. We propose an integrated scheme to address this problem. We adopt adaptive sampling to compress the dataset, and the cross curve of the data compression ratio and correlation coefficient between the initial and sampled data is used to choose the damping factor for adaptive sampling. Then, the conventional inversion algorithm in model space is transformed to data space, using the identity relationship between different matrices, which greatly reduces the memory requirement. Finally, parallel computation is employed to accelerate calculation of the kernel function. We use the conjugate gradient method to minimize the objective function and a damping factor is introduced to stabilize the iterative process. A wide variety of constraint options are also considered, such as depth weighing, sparseness, and boundary limits. We design a synthetic magnetic model with three prismatic susceptibility causative bodies to demonstrate the effectiveness of the proposed scheme. Tests on synthetic data show that the proposed scheme provides significant reduction in memory and time consumption, and the inversion result is reliable. These advantages hold true for practical field magnetic data from the Hawsons mining area in Australia, verifying the effectiveness of the proposed scheme.

  4. Efficiency and Flexibility of Fingerprint Scheme Using Partial Encryption and Discrete Wavelet Transform to Verify User in Cloud Computing.

    PubMed

    Yassin, Ali A

    2014-01-01

    Now, the security of digital images is considered more and more essential and fingerprint plays the main role in the world of image. Furthermore, fingerprint recognition is a scheme of biometric verification that applies pattern recognition techniques depending on image of fingerprint individually. In the cloud environment, an adversary has the ability to intercept information and must be secured from eavesdroppers. Unluckily, encryption and decryption functions are slow and they are often hard. Fingerprint techniques required extra hardware and software; it is masqueraded by artificial gummy fingers (spoof attacks). Additionally, when a large number of users are being verified at the same time, the mechanism will become slow. In this paper, we employed each of the partial encryptions of user's fingerprint and discrete wavelet transform to obtain a new scheme of fingerprint verification. Moreover, our proposed scheme can overcome those problems; it does not require cost, reduces the computational supplies for huge volumes of fingerprint images, and resists well-known attacks. In addition, experimental results illustrate that our proposed scheme has a good performance of user's fingerprint verification.

  5. A hierarchical storage management (HSM) scheme for cost-effective on-line archival using lossy compression.

    PubMed

    Avrin, D E; Andriole, K P; Yin, L; Gould, R G; Arenson, R L

    2001-03-01

    A hierarchical storage management (HSM) scheme for cost-effective on-line archival of image data using lossy compression is described. This HSM scheme also provides an off-site tape backup mechanism and disaster recovery. The full-resolution image data are viewed originally for primary diagnosis, then losslessly compressed and sent off site to a tape backup archive. In addition, the original data are wavelet lossy compressed (at approximately 25:1 for computed radiography, 10:1 for computed tomography, and 5:1 for magnetic resonance) and stored on a large RAID device for maximum cost-effective, on-line storage and immediate retrieval of images for review and comparison. This HSM scheme provides a solution to 4 problems in image archiving, namely cost-effective on-line storage, disaster recovery of data, off-site tape backup for the legal record, and maximum intermediate storage and retrieval through the use of on-site lossy compression.

  6. Future efficiency of run of the river hydropower schemes based on climate change scenarios: case study in UK catchments

    NASA Astrophysics Data System (ADS)

    Pasten Zapata, Ernesto; Moggridge, Helen; Jones, Julie; Widmann, Martin

    2017-04-01

    Run-of-the-River (ROR) hydropower schemes are expected to be importantly affected by climate change as they rely in the availability of river flow to generate energy. As temperature and precipitation are expected to vary in the future, the hydrological cycle will also undergo changes. Therefore, climate models based on complex physical atmospheric interactions have been developed to simulate future climate scenarios considering the atmosphere's greenhouse gas concentrations. These scenarios are classified according to the Representative Concentration Pathways (RCP) that are generated according to the concentration of greenhouse gases. This study evaluates possible scenarios for selected ROR hydropower schemes within the UK, considering three different RCPs: 2.6, 4.5 and 8.5 W/m2 for 2100 relative to pre-industrial values. The study sites cover different climate, land cover, topographic and hydropower scheme characteristics representative of the UK's heterogeneity. Precipitation and temperature outputs from state-of-the-art Regional Climate Models (RCMs) from the Euro-CORDEX project are used as input for a HEC-HMS hydrological model to simulate the future river flow available. Both uncorrected and bias-corrected RCM simulations are analyzed. The results of this project provide an insight of the possible effects of climate change towards the generation of power from the ROR hydropower schemes according to the different RCP scenarios and contrasts the results obtained from uncorrected and bias-corrected RCMs. This analysis can aid on the adaptation to climate change as well as the planning of future ROR schemes in the region.

  7. Does the implementation of responsibility centers, total quality management, and physician fee programs improve hospital efficiency? Evidence from Taiwan hospitals.

    PubMed

    Chu, Hsuan-Lien; Liu, Shuen-Zen; Romeis, James C

    2002-12-01

    This study evaluates whether the implementation of various types of hospital-physician integration strategies, such as the responsibility centers system, total quality management, and physician fee programs, enhance efficiency for Taiwan hospitals. Because hospitals in Taiwan are structurally similar to staff-model HMOs, the study has implications beyond Taiwan. The Data Envelopment Analysis model is applied to measure hospital efficiency. Hospital efficiency refers to the ability to produce more outputs (eg, ambulatory and emergency visits, inpatient days, and inpatient visits) with the same inputs (eg, physicians, nurses, ancillary labor, and hospital beds). The sample consists of 90 general hospitals in Taiwan from 1994 to 1996. In addition, multitobit regression analysis is used to simultaneously estimate the effects of the hospital-physician integration strategies and provide better control for the effect of other factors (eg, size, degree of competition, ownership structure, teaching status, and the change in regulatory regime) that may also affect hospital efficiency. When evaluating the hospital-physician integration strategies individually, hospitals that implemented the responsibility centers system, total quality management, and physician fee programs were more efficient than hospitals that did not. Controlling for other factors using the multitobit model, hospitals that implemented physician fee programs remained significantly more efficient than others. In addition, hospitals that implemented total quality management were more efficient when they had implemented the strategy for at least 2 years. Hospitals that implemented the responsibility centers system were more efficient but only when integrating the system with formal incentive schemes. Physician fee programs seem to provide the most direct and robust incentives to enhance hospital efficiency under a fee-for-service regime like that in Taiwan. Because of time-lagged effects, hospitals that

  8. Techniques for Efficiently Managing Large Geosciences Data Sets

    NASA Astrophysics Data System (ADS)

    Kruger, A.; Krajewski, W. F.; Bradley, A. A.; Smith, J. A.; Baeck, M. L.; Steiner, M.; Lawrence, R. E.; Ramamurthy, M. K.; Weber, J.; Delgreco, S. A.; Domaszczynski, P.; Seo, B.; Gunyon, C. A.

    2007-12-01

    We have developed techniques and software tools for efficiently managing large geosciences data sets. While the techniques were developed as part of an NSF-Funded ITR project that focuses on making NEXRAD weather data and rainfall products available to hydrologists and other scientists, they are relevant to other geosciences disciplines that deal with large data sets. Metadata, relational databases, data compression, and networking are central to our methodology. Data and derived products are stored on file servers in a compressed format. URLs to, and metadata about the data and derived products are managed in a PostgreSQL database. Virtually all access to the data and products is through this database. Geosciences data normally require a number of processing steps to transform the raw data into useful products: data quality assurance, coordinate transformations and georeferencing, applying calibration information, and many more. We have developed the concept of crawlers that manage this scientific workflow. Crawlers are unattended processes that run indefinitely, and at set intervals query the database for their next assignment. A database table functions as a roster for the crawlers. Crawlers perform well-defined tasks that are, except for perhaps sequencing, largely independent from other crawlers. Once a crawler is done with its current assignment, it updates the database roster table, and gets its next assignment by querying the database. We have developed a library that enables one to quickly add crawlers. The library provides hooks to external (i.e., C-language) compiled codes, so that developers can work and contribute independently. Processes called ingesters inject data into the system. The bulk of the data are from a real-time feed using UCAR/Unidata's IDD/LDM software. An exciting recent development is the establishment of a Unidata HYDRO feed that feeds value-added metadata over the IDD/LDM. Ingesters grab the metadata and populate the Postgre

  9. A distributed scheme to manage the dynamic coexistence of IEEE 802.15.4-based health-monitoring WBANs.

    PubMed

    Deylami, Mohammad N; Jovanov, Emil

    2014-01-01

    The overlap of transmission ranges between wireless networks as a result of mobility is referred to as dynamic coexistence. The interference caused by coexistence may significantly affect the performance of wireless body area networks (WBANs) where reliability is particularly critical for health monitoring applications. In this paper, we analytically study the effects of dynamic coexistence on the operation of IEEE 802.15.4-based health monitoring WBANs. The current IEEE 802.15.4 standard lacks mechanisms for effectively managing the coexistence of mobile WBANs. Considering the specific characteristics and requirements of health monitoring WBANs, we propose the dynamic coexistence management (DCM) mechanism to make IEEE 802.15.4-based WBANs able to detect and mitigate the harmful effects of coexistence. We assess the effectiveness of this scheme using extensive OPNET simulations. Our results indicate that DCM improves the successful transmission rates of dynamically coexisting WBANs by 20%-25% for typical medical monitoring applications.

  10. Agroecosystems, nitrogen-use efficiency, and nitrogen management.

    PubMed

    Cassman, Kenneth G; Dobermann, Achim; Walters, Daniel T

    2002-03-01

    The global challenge of meeting increased food demand and protecting environmental quality will be won or lost in cropping systems that produce maize, rice, and wheat. Achieving synchrony between N supply and crop demand without excess or deficiency is the key to optimizing trade-offs amongst yield, profit, and environmental protection in both large-scale systems in developed countries and small-scale systems in developing countries. Setting the research agenda and developing effective policies to meet this challenge requires quantitative understanding of current levels of N-use efficiency and losses in these systems, the biophysical controls on these factors, and the economic returns from adoption of improved management practices. Although advances in basic biology, ecology, and biogeochemistry can provide answers, the magnitude of the scientific challenge should not be underestimated because it becomes increasingly difficult to control the fate of N in cropping systems that must sustain yield increases on the world's limited supply of productive farm land.

  11. Comparing Nitrous Oxide Emissions from Three Residential Landscapes under Different Management Schemes Following Natural Rainfall Events

    EPA Science Inventory

    Cultural lawn management practices that produce aesthetically appealing landscapes may also create environmental conditions that stimulate soil nitrous oxide (N2O) emissions. The purpose of this study is to investigate the effects of lawn management practices on N2O fluxes from ...

  12. Comparing Nitrous Oxide Emissions from Three Residential Landscapes under Different Management Schemes Following Natural Rainfall Events

    EPA Science Inventory

    Cultural lawn management practices that produce aesthetically appealing landscapes may also create environmental conditions that stimulate soil nitrous oxide (N2O) emissions. The purpose of this study is to investigate the effects of lawn management practices on N2O fluxes from ...

  13. Scheme for efficient extraction of low-frequency signal beyond the quantum limit by frequency-shift detection.

    PubMed

    Yang, R G; Zhang, J; Zhai, Z H; Zhai, S Q; Liu, K; Gao, J R

    2015-08-10

    Low-frequency (Hz~kHz) squeezing is very important in many schemes of quantum precision measurement. But it is more difficult than that at megahertz-frequency because of the introduction of laser low-frequency technical noise. In this paper, we propose a scheme to obtain a low-frequency signal beyond the quantum limit from the frequency comb in a non-degenerate frequency and degenerate polarization optical parametric amplifier (NOPA) operating below threshold with type I phase matching by frequency-shift detection. Low-frequency squeezing immune to laser technical noise is obtained by a detection system with a local beam of two-frequency intense laser. Furthermore, the low-frequency squeezing can be used for phase measurement in Mach-Zehnder interferometer, and the signal-to-noise ratio (SNR) can be enhanced greatly.

  14. Innovative Technologies for Efficient Pharmacotherapeutic Management in Space

    NASA Technical Reports Server (NTRS)

    Putcha, Lakshmi; Daniels, Vernie

    2014-01-01

    Current and future Space exploration missions and extended human presence in space aboard the ISS will expose crew to risks that differ both quantitatively and qualitatively from those encountered before by space travelers and will impose an unknown risk of safety and crew health. The technology development challenges for optimizing therapeutics in space must include the development of pharmaceuticals with extended stability, optimal efficacy and bioavailability with minimal toxicity and side effects. Innovative technology development goals may include sustained/chronic delivery preventive health care products and vaccines, low-cost high-efficiency noninvasive, non-oral dosage forms with radio-protective formulation matrices and dispensing technologies coupled with self-reliant tracking technologies for quality assurance and quality control assessment. These revolutionary advances in pharmaceutical technology will assure human presence in space and healthy living on Earth. Additionally, the Joint Commission on Accreditation of Healthcare Organizations advocates the use of health information technologies to effectively execute all aspects of medication management (prescribing, dispensing, and administration). The advent of personalized medicine and highly streamlined treatment regimens stimulated interest in new technologies for medication management. Intelligent monitoring devices enhance medication accountability compliance, enable effective drug use, and offer appropriate storage and security conditions for dangerous drug and controlled substance medications in remote sites where traditional pharmacies are unavailable. These features are ideal for Exploration Medical Capabilities. This presentation will highlight current novel commercial off-the-shelf (COTS) intelligent medication management devices for the unique dispensing, therapeutic drug monitoring, medication tracking, and drug delivery demands of exploration space medical operations.

  15. Defect Profile Estimation from Magnetic Flux Leakage Signal via Efficient Managing Particle Swarm Optimization

    PubMed Central

    Han, Wenhua; Xu, Jun; Wang, Ping; Tian, Guiyun

    2014-01-01

    In this paper, efficient managing particle swarm optimization (EMPSO) for high dimension problem is proposed to estimate defect profile from magnetic flux leakage (MFL) signal. In the proposed EMPSO, in order to strengthen exchange of information among particles, particle pair model was built. For more efficient searching when facing different landscapes of problems, velocity updating scheme including three velocity updating models was also proposed. In addition, for more chances to search optimum solution out, automatic particle selection for re-initialization was implemented. The optimization results of six benchmark functions show EMPSO performs well when optimizing 100-D problems. The defect simulation results demonstrate that the inversing technique based on EMPSO outperforms the one based on self-learning particle swarm optimizer (SLPSO), and the estimated profiles are still close to the desired profiles with the presence of low noise in MFL signal. The results estimated from real MFL signal by EMPSO-based inversing technique also indicate that the algorithm is capable of providing an accurate solution of the defect profile with real signal. Both the simulation results and experiment results show the computing time of the EMPSO-based inversing technique is reduced by 20%–30% than that of the SLPSO-based inversing technique. PMID:24926693

  16. Reviewing the economic efficiency of disaster risk management

    NASA Astrophysics Data System (ADS)

    Mechler, Reinhard

    2013-04-01

    There is a lot of rhetoric suggesting that disaster risk management (DRM) pays, yet surprisingly little in the way of hard facts. Cost-benefit analysis (CBA) is one major tool that can provide quantitative information about the prioritization of disaster risk management (DRM) (and climate adaptation) based on economic principles. Yet, on a global scale, there has been surprisingly little robust evidence on the economic efficiency and benefits of risk management measures. This review shows that for the limited evidence reported the economic case for DRM across a range of hazards is strong and that the benefits of investing in DRM outweigh the costs of doing so, on average, by about four times the cost in terms of avoided and reduced losses. Most studies using a CBA approach focus on structural DRM and most information has been made available on physical flood prevention. There have been some limited studies on preparedness and risk financing. The global evidence base is limited and estimates appear not very solid, and overall, in line with the conclusion of the recent IPCC SREX report, there is limited evidence and medium agreement across the literature. Some of the factors behind the limited robustness are inherent to CBA more widely: these challenges comprise the inability to price intangibles, evaluating strategies rather than single projects, difficulties in assessing softer rather than infrastructure-related options, choices regarding a proper discount rate, lack of accounting for the distribution of benefits and costs and difficulties with assessing nonmarket values such as those related to health, the environment, or public goods. Although techniques exist to address some of these challenges, they are not very likely to easily go away. Other challenges associated specifically with DRM, such as the need and difficulty to undertake risk -based analysis can be overcome, and there have been manuals and reports providing a way forward. In an age of austerity, cost

  17. Efficient Management of Multiple Piconets in an MC-CDMA-Based UWB System

    NASA Astrophysics Data System (ADS)

    Gong, Peng; Xue, Peng; Piao, Cheng Jie; Kim, Duk Kyung

    With multiple overlapped piconets, the IEEE 802.15.3 Medium Access Control (MAC) protocol uses a Parent/Child (P/C) or Parent/Neighbor (P/N) configuration to avoid inter-piconet interference. However, the throughput of a P/N or P/C configuration cannot exceed that of a single piconet. In the present paper we propose an efficient means of managing multiple piconets to cooperate with a Multi-Carrier Code Division Multiple Access (MC-CDMA) based UWB system. The proposed management approach uses an Intermediate Device (IDEV) to connect Piconet Coordinators (PNCs). A senior PNC adaptively arranges two simultaneous data transmission links with the proposed spreading matrices in each Channel Time Allocation (CTA) instead of a P/C or P/N configuration, which supports only a single link in each CTA. Simulation results demonstrate the proposed scheme can achieve a higher throughput with an acceptable compromise of link success probability in multiple overlapped piconets.

  18. Participatory innovation process for testing new practices for soil fertility management in Chókwè Irrigation Scheme (Mozambique)

    NASA Astrophysics Data System (ADS)

    Sánchez Reparaz, Maite; de Vente, Joris; Famba, Sebastiao; Rougier, Jean-Emmanuel; Ángel Sánchez-Monedero, Miguel; Barberá, Gonzalo G.

    2015-04-01

    Integrated water and nutrient management are key factors to increase productivity and to reduce the yield gap in irrigated systems in Sub-Saharan Africa. These two elements are affected by an ensemble of abiotic, biotic, management and socio-economic factors that need to be taken into account to reduce the yield gap, as well as farmers' perceptions and knowledge. In the framework of the project European Union and African Union cooperative research to increase Food production in irrigated farming systems in Africa (EAU4Food project) we are carrying out a participatory innovation process in Chókwè irrigation scheme (Mozambique) based on stakeholders engagement, to test new practices for soil fertility management that can increase yields reducing costs. Through a method combining interviews with three farmers' associations and other relevant stakeholders and soil sampling from the interviewed farmers' plots with the organization of Communities of Practices, we tried to capture how soil fertility is managed by farmers, the constraints they find as well as their perceptions about soil resources. This information was the basis to design and conduct a participatory innovation process where compost made with rice straw and manure is being tested by a farmers' association. Most important limitations of the method are also evaluated. Our results show that socio-economic characteristics of farmers condition how they manage soil fertility and their perceptions. The difficulties they face to adopt new practices for soil fertility management, mainly related to economic resources limitations, labour availability, knowledge time or farm structure, require a systemic understanding that takes into account abiotic, biotic, management and socio-economic factors and their implication as active stakeholders in all phases of the innovation process.

  19. An efficient light trapping scheme based on textured conductive photonic crystal back reflector for performance improvement of amorphous silicon solar cells

    SciTech Connect

    Chen, Peizhuan; Hou, Guofu Huang, Qian; Zhao, Jing; Zhang, Jianjun Ni, Jian; Zhang, Xiaodan; Zhao, Ying; Fan, QiHua

    2014-08-18

    An efficient light trapping scheme named as textured conductive photonic crystal (TCPC) has been proposed and then applied as a back-reflector (BR) in n-i-p hydrogenated amorphous silicon (a-Si:H) solar cell. This TCPC BR combined a flat one-dimensional photonic crystal and a randomly textured surface of chemically etched ZnO:Al. Total efficiency enhancement was obtained thanks to the sufficient conductivity, high reflectivity and strong light scattering of the TCPC BR. Unwanted intrinsic losses of surface plasmon modes are avoided. An initial efficiency of 9.66% for a-Si:H solar cell was obtained with short-circuit current density of 14.74 mA/cm{sup 2}, fill factor of 70.3%, and open-circuit voltage of 0.932 V.

  20. Increased malaria transmission around irrigation schemes in Ethiopia and the potential of canal water management for malaria vector control.

    PubMed

    Kibret, Solomon; Wilson, G Glenn; Tekie, Habte; Petros, Beyene

    2014-09-13

    Irrigation schemes have been blamed for the increase in malaria in many parts of sub-Saharan Africa. However, proper water management could help mitigate malaria around irrigation schemes in this region. This study investigates the link between irrigation and malaria in Central Ethiopia. Larval and adult mosquitoes were collected fortnightly between November 2009 and October 2010 from two irrigated and two non-irrigated (control) villages in the Ziway area, Central Ethiopia. Daily canal water releases were recorded during the study period and bi-weekly correlation analysis was done to determine relationships between canal water releases and larval/adult vector densities. Blood meal sources (bovine vs human) and malaria sporozoite infection were tested using enzyme-linked immunosorbent assay (ELISA). Monthly malaria data were also collected from central health centre of the study villages. Monthly malaria incidence was over six-fold higher in the irrigated villages than the non-irrigated villages. The number of anopheline breeding habitats was 3.6 times higher in the irrigated villages than the non-irrigated villages and the most common Anopheles mosquito breeding habitats were waterlogged field puddles, leakage pools from irrigation canals and poorly functioning irrigation canals. Larval and adult anopheline densities were seven- and nine-fold higher in the irrigated villages than in the non-irrigated villages, respectively, during the study period. Anopheles arabiensis was the predominant species in the study area. Plasmodium falciparum sporozoite rates of An. arabiensis and Anopheles pharoensis were significantly higher in the irrigated villages than the non-irrigated villages. The annual entomological inoculation rate (EIR) calculated for the irrigated and non-irrigated villages were 34.8 and 0.25 P. falciparum infective bites per person per year, respectively. A strong positive correlation was found between bi-weekly anopheline larval density and canal water

  1. A mesh adaptivity scheme on the Landau-de Gennes functional minimization case in 3D, and its driving efficiency

    NASA Astrophysics Data System (ADS)

    Bajc, Iztok; Hecht, Frédéric; Žumer, Slobodan

    2016-09-01

    This paper presents a 3D mesh adaptivity strategy on unstructured tetrahedral meshes by a posteriori error estimates based on metrics derived from the Hessian of a solution. The study is made on the case of a nonlinear finite element minimization scheme for the Landau-de Gennes free energy functional of nematic liquid crystals. Newton's iteration for tensor fields is employed with steepest descent method possibly stepping in. Aspects relating the driving of mesh adaptivity within the nonlinear scheme are considered. The algorithmic performance is found to depend on at least two factors: when to trigger each single mesh adaptation, and the precision of the correlated remeshing. Each factor is represented by a parameter, with its values possibly varying for every new mesh adaptation. We empirically show that the time of the overall algorithm convergence can vary considerably when different sequences of parameters are used, thus posing a question about optimality. The extensive testings and debugging done within this work on the simulation of systems of nematic colloids substantially contributed to the upgrade of an open source finite element-oriented programming language to its 3D meshing possibilities, as also to an outer 3D remeshing module.

  2. An efficient and stable hybrid extended Lagrangian/self-consistent field scheme for solving classical mutual induction

    SciTech Connect

    Albaugh, Alex; Demerdash, Omar; Head-Gordon, Teresa

    2015-11-07

    We have adapted a hybrid extended Lagrangian self-consistent field (EL/SCF) approach, developed for time reversible Born Oppenheimer molecular dynamics for quantum electronic degrees of freedom, to the problem of classical polarization. In this context, the initial guess for the mutual induction calculation is treated by auxiliary induced dipole variables evolved via a time-reversible velocity Verlet scheme. However, we find numerical instability, which is manifested as an accumulation in the auxiliary velocity variables, that in turn results in an unacceptable increase in the number of SCF cycles to meet even loose convergence tolerances for the real induced dipoles over the course of a 1 ns trajectory of the AMOEBA14 water model. By diagnosing the numerical instability as a problem of resonances that corrupt the dynamics, we introduce a simple thermostating scheme, illustrated using Berendsen weak coupling and Nose-Hoover chain thermostats, applied to the auxiliary dipole velocities. We find that the inertial EL/SCF (iEL/SCF) method provides superior energy conservation with less stringent convergence thresholds and a correspondingly small number of SCF cycles, to reproduce all properties of the polarization model in the NVT and NVE ensembles accurately. Our iEL/SCF approach is a clear improvement over standard SCF approaches to classical mutual induction calculations and would be worth investigating for application to ab initio molecular dynamics as well.

  3. A Novel Energy Efficient Topology Control Scheme Based on a Coverage-Preserving and Sleep Scheduling Model for Sensor Networks

    PubMed Central

    Shi, Binbin; Wei, Wei; Wang, Yihuai; Shu, Wanneng

    2016-01-01

    In high-density sensor networks, scheduling some sensor nodes to be in the sleep mode while other sensor nodes remain active for monitoring or forwarding packets is an effective control scheme to conserve energy. In this paper, a Coverage-Preserving Control Scheduling Scheme (CPCSS) based on a cloud model and redundancy degree in sensor networks is proposed. Firstly, the normal cloud model is adopted for calculating the similarity degree between the sensor nodes in terms of their historical data, and then all nodes in each grid of the target area can be classified into several categories. Secondly, the redundancy degree of a node is calculated according to its sensing area being covered by the neighboring sensors. Finally, a centralized approximation algorithm based on the partition of the target area is designed to obtain the approximate minimum set of nodes, which can retain the sufficient coverage of the target region and ensure the connectivity of the network at the same time. The simulation results show that the proposed CPCSS can balance the energy consumption and optimize the coverage performance of the sensor network. PMID:27754405

  4. A Novel Energy Efficient Topology Control Scheme Based on a Coverage-Preserving and Sleep Scheduling Model for Sensor Networks.

    PubMed

    Shi, Binbin; Wei, Wei; Wang, Yihuai; Shu, Wanneng

    2016-10-14

    In high-density sensor networks, scheduling some sensor nodes to be in the sleep mode while other sensor nodes remain active for monitoring or forwarding packets is an effective control scheme to conserve energy. In this paper, a Coverage-Preserving Control Scheduling Scheme (CPCSS) based on a cloud model and redundancy degree in sensor networks is proposed. Firstly, the normal cloud model is adopted for calculating the similarity degree between the sensor nodes in terms of their historical data, and then all nodes in each grid of the target area can be classified into several categories. Secondly, the redundancy degree of a node is calculated according to its sensing area being covered by the neighboring sensors. Finally, a centralized approximation algorithm based on the partition of the target area is designed to obtain the approximate minimum set of nodes, which can retain the sufficient coverage of the target region and ensure the connectivity of the network at the same time. The simulation results show that the proposed CPCSS can balance the energy consumption and optimize the coverage performance of the sensor network.

  5. Economic efficiency and risk character of fire management programs, Northern Rocky Mountains

    Treesearch

    Thomas J. Mills; Frederick W. Bratten

    1988-01-01

    Economic efficiency and risk have long been considered during the selection of fire management programs and the design of fire management polices. The risk considerations was largely subjective, however, and efficiency has only recently been calculated for selected portions of the fire management program. The highly stochastic behavior of the fire system and the high...

  6. Information Management and Librarianship: Development of an Innovative Program through a Cooperative Link Scheme.

    ERIC Educational Resources Information Center

    Evans, John; Treloar, Andrew

    1994-01-01

    Describes the development of a cooperative initiative between the Department of Library and Information Studies at the University of Papua New Guinea and the Information Management department at Deakin University. Highlights include curriculum change; new bachelor degree programs; and program delivery, including conventional instruction and…

  7. Using the Staff Sharing Scheme to Support School Staff in Managing Challenging Behaviour More Effectively

    ERIC Educational Resources Information Center

    Jones, Daniel; Monsen, Jeremy; Franey, John

    2013-01-01

    This paper explores how educational psychologists working in a training/consultative way can enable teachers to manage challenging pupil behaviour more effectively. It sets out a rationale which encourages schools to embrace a group based teacher peer-support system as part of regular school development. It then explores the usefulness of the…

  8. Management of Universal Basic Education Scheme (U.B.E.) for Qualitative Education in Nigeria

    ERIC Educational Resources Information Center

    Omotayo, Dare Michael; Ihebereme, Chioma; Maduewesi, Sir B. U.

    2008-01-01

    Since independence, Nigeria has been searching diligently for a viable educational system capable of enhancing the socio-economic and political values inherent in the country. This paper discusses concepts such as management, qualitative education and Universal Basic Education. In addition to the above, the paper also examines the National…

  9. Using the Staff Sharing Scheme to Support School Staff in Managing Challenging Behaviour More Effectively

    ERIC Educational Resources Information Center

    Jones, Daniel; Monsen, Jeremy; Franey, John

    2013-01-01

    This paper explores how educational psychologists working in a training/consultative way can enable teachers to manage challenging pupil behaviour more effectively. It sets out a rationale which encourages schools to embrace a group based teacher peer-support system as part of regular school development. It then explores the usefulness of the…

  10. Analog-model simulations for secondary canal controls and forward pumping water-management schemes in southeast Florida

    USGS Publications Warehouse

    Cordes, E.H.; Gardner, Richard Alfred

    1976-01-01

    The analog model of the Biscayne aquifer of southeast Florida was used to approximate the effects of two proposed water-management schemes. One involved adding a secondary control structure in a major canal which is controlled near the coast. In the model the controls were operated in accordance with canal water level both above and below the secondary control. Although the model could not differentiate between control openings of 1 foot or 5 feet, it showed that the secondary control is a viable method of conserving ground water. The second scheme involved pumping ground water ('forward pumping') from the Biscayne aquifer in inland areas during the dry season to: (1) augment canal flows toward the coast to sustain ground-water levels there, and (2) generate additional ground-water storage space for recharge in the wet season. Several sites on the model were programmed for forward pumping wells and the storage change was noted as a percentage of the ground-water withdrawal. (Woodard-USGS)

  11. Orthogonal frequency division multiplexing with amplitude shift keying subcarrier modulation as a reliable and efficient transmission scheme for self-mixing receivers

    NASA Astrophysics Data System (ADS)

    Kornprobst, Jonas; Mittermaier, Thomas J.; Eibert, Thomas F.

    2017-09-01

    A new receiving scheme for self-mixing receivers is presented that overcomes the disadvantages of the self-heterodyne concept. Generally speaking, the self-mixing receiver offers immunity to phase noise and frequency offsets, especially at very high frequencies, since it does not require radio frequency local oscillators. Our proposed technique eliminates the drawbacks of the self-heterodyne transmission scheme, which are the poor power efficiency and the strong dependence on the continously transmitted carrier. A nonlinear system of equations is constructed that describes a phase retrieval problem for the reconstruction of the original transmit signal before self-mixing. Two different solution strategies, with restrictions in time and frequency domain, are presented. As a consequence, the self-mixing equation system is shown to be solvable with some a-priori information about the transmit signal. With this novel approach, the transmitted information is distributed over the full available bandwidth, and there is no special dependence on a certain subcarrier for the down-conversion. The general performance, regarding bit error ratio over signal to noise ratio, is improved by at least 2 dB as compared to the self-heterodyne transmission scheme. In the case of frequency selective channels, e.g. multi-path propagation, this improvement is shown to be much larger, because the presented approach is able to reconstruct the received subcarriers without the necessity of receiving all subcarriers.

  12. Economic efficiency of environmental management system operation in industrial companies

    NASA Astrophysics Data System (ADS)

    Dukmasova, N.; Ershova, I.; Plastinina, I.; Boyarinov, A.

    2017-06-01

    The article examines the issue of the efficiency of the environmental management system (EMS) implementation in the Russian machine-building companies. The analysis showed that Russia clearly lags behind other developed and developing countries in terms of the number of ISO 14001 certified companies. According to the authors, the main cause of weak system implementation activity is attributed to the lack of interest in ISO 14001 certification on the Russian market. Five-year primary (field) research aimed at the analysis of the environmental priorities of the civilians suggests that the image component of the economic benefits ensures the increase in economic and financial performance of the company due to the increase in customers’ loyalty to the products of the EMS adopter. To quantify economic benefits obtained from EMS implementation, a methodological approach with regard to the image component and the decrease in semi-fixed costs due to the increase in the production scale has been developed. This approach has been tested in a machine-building electrical equipment manufacturer in Ekaterinburg. This approach applied to data processing yields the conclusion that EMS gives a good additional competitive advantage to its adopters.

  13. Position statement on efficiency of technologies for diabetes management.

    PubMed

    Martín-Vaquero, Pilar; Martínez-Brocca, María Asunción; García-López, José Manuel

    2014-12-01

    Di@bet.es study results are impressive, showing that diabetes affects 13.8% of the Spanish population. Not only the statistical facts are alarming, but the increasing incidence of this disease is a major problem, as pandemic proportions of type 2 diabetes are expected. Thus, the study of diabetes represents a challenge not only for health services, but also for the Ministries of Health and Finance. Technology has become an essential tool in the quality are of patients with diabetes, as it helps in the healthcare processes to obtain an optimum metabolic balance and prevent possible complications. Insulin pumps, continuous glucose monitoring nd self-monitoring blood glucose have all proved their efficiency, and telemedicine it is making good progress. The indirect costs of diabetes in Spain are much higher than the directones, showing the importance of inverting the paradox. The optimization of resources depends not only on the ability of the physicians, but also the administration, to implant and sustain technological innovations in our system, and with that make it effective in terms of benefits. Cost-effectiveness and cost-utility analysis are needed to prioritize and allow health management services to make the correct choices for approaching this prevalent chronic disease.

  14. GIS based malaria information management system for urban malaria scheme in India.

    PubMed

    Srivastava, Aruna; Nagpal, B N; Saxena, Rekha; Eapen, Alex; Ravindran, K John; Subbarao, S K; Rajamanikam, C; Palanisamy, M; Kalra, N L; Appavoo, N C

    2003-05-01

    A GIS based information management system has been developed to help Urban Malaria Control in India. The basic objective is to develop a model to assist planning and implementation of a suitable control measure. The system can help in: (i) identifying high receptive areas in time and space domain; (ii) identifying risk factors for high receptivity; (iii) monitoring and evaluating control measures. To demonstrate this system, information on 33 parameters and malaria cases has been attached to a digitised map of Dindigul, an urban town in Tamil Nadu. Functionalities of the system and its utility are described in this paper. A GIS based information management system ensures that if a localised spurt of the disease occurs, it can be associated rapidly with a likely cause, a specific vector, and a probable human source, so that appropriate preventive action can be taken to arrest any rising trend.

  15. An adaptive undersampling scheme of wavelet-encoded parallel MR imaging for more efficient MR data acquisition

    NASA Astrophysics Data System (ADS)

    Xie, Hua; Bosshard, John C.; Hill, Jason E.; Wright, Steven M.; Mitra, Sunanda

    2016-03-01

    Magnetic Resonance Imaging (MRI) offers noninvasive high resolution, high contrast cross-sectional anatomic images through the body. The data of the conventional MRI is collected in spatial frequency (Fourier) domain, also known as kspace. Because there is still a great need to improve temporal resolution of MRI, Compressed Sensing (CS) in MR imaging is proposed to exploit the sparsity of MR images showing great potential to reduce the scan time significantly, however, it poses its own unique problems. This paper revisits wavelet-encoded MR imaging which replaces phase encoding in conventional MRI data acquisition with wavelet encoding by applying wavelet-shaped spatially selective radiofrequency (RF) excitation, and keeps the readout direction as frequency encoding. The practicality of wavelet encoded MRI by itself is limited due to the SNR penalties and poor time resolution compared to conventional Fourier-based MRI. To compensate for those disadvantages, this paper first introduces an undersampling scheme named significance map for sparse wavelet-encoded k-space to speed up data acquisition as well as allowing for various adaptive imaging strategies. The proposed adaptive wavelet-encoded undersampling scheme does not require prior knowledge of the subject to be scanned. Multiband (MB) parallel imaging is also incorporated with wavelet-encoded MRI by exciting multiple regions simultaneously for further reduction in scan time desirable for medical applications. The simulation and experimental results are presented showing the feasibility of the proposed approach in further reduction of the redundancy of the wavelet k-space data while maintaining relatively high quality.

  16. Efficient Z-scheme photocatalyst from simultaneous decoration of In2S3 nanosheets and WO3 nanorods on graphene sheets

    NASA Astrophysics Data System (ADS)

    Zhang, Qingran; Luo, Mingbo; Sun, Ya-Ping; Liu, Yuanfang; Cao, Aoneng

    2016-07-01

    Inspired by natural photosynthesis, the Z-scheme photocatalyst is a promising approach to extend the absorption spectra of photocatalysts and reduce the recombination of photo-generated electrons and holes. However, the fabrication of well-structured efficient multi-component Z-scheme photocatalysts is still a big challenge. We report here a facile one-pot method to synthesize graphene-based Z-scheme photocatalysts. The one-pot method guarantees good distribution of well-structured individual components on thin-layered rGO sheets with excellent connections. With inactive WO3 nanorods and inactive β-In2S3 nanosheets attached to the surface of the rGO sheets, the synthesized In2S3/WO3/rGO tertiary nanocomposite shows excellent visible-light catalytic activity for hydrogen production at 1524 μmol g-1 h-1, demonstrating unambiguously the Z-scheme catalytic mechanism. To prevent cross-reactions and interferences, our strategy was to choose no more than one ionic precipitation reaction for the one-pot process, as unwanted cross-reactions could become inevitable if many cations and anions were present. This fabrication strategy should be applicable generally to synthesize other multiple-component nanocomposites, as demonstrated also by the preliminary results of the successful synthesis of the BiVO4/WO3/rGO nanocomposite (one ionic precipitation reaction and one hydrolysis reaction) and WO3/TiO2/rGO nanocomposite (two hydrolysis reactions).

  17. Efficient Z-scheme photocatalyst from simultaneous decoration of In2S3 nanosheets and WO3 nanorods on graphene sheets.

    PubMed

    Zhang, Qingran; Luo, Mingbo; Sun, Ya-Ping; Liu, Yuanfang; Cao, Aoneng

    2016-07-15

    Inspired by natural photosynthesis, the Z-scheme photocatalyst is a promising approach to extend the absorption spectra of photocatalysts and reduce the recombination of photo-generated electrons and holes. However, the fabrication of well-structured efficient multi-component Z-scheme photocatalysts is still a big challenge. We report here a facile one-pot method to synthesize graphene-based Z-scheme photocatalysts. The one-pot method guarantees good distribution of well-structured individual components on thin-layered rGO sheets with excellent connections. With inactive WO3 nanorods and inactive β-In2S3 nanosheets attached to the surface of the rGO sheets, the synthesized In2S3/WO3/rGO tertiary nanocomposite shows excellent visible-light catalytic activity for hydrogen production at 1524 μmol g(-1) h(-1), demonstrating unambiguously the Z-scheme catalytic mechanism. To prevent cross-reactions and interferences, our strategy was to choose no more than one ionic precipitation reaction for the one-pot process, as unwanted cross-reactions could become inevitable if many cations and anions were present. This fabrication strategy should be applicable generally to synthesize other multiple-component nanocomposites, as demonstrated also by the preliminary results of the successful synthesis of the BiVO4/WO3/rGO nanocomposite (one ionic precipitation reaction and one hydrolysis reaction) and WO3/TiO2/rGO nanocomposite (two hydrolysis reactions).

  18. Nanofluidic crystal: a facile, high-efficiency and high-power-density scaling up scheme for energy harvesting based on nanofluidic reverse electrodialysis.

    PubMed

    Ouyang, Wei; Wang, Wei; Zhang, Haixia; Wu, Wengang; Li, Zhihong

    2013-08-30

    The great advances in nanotechnology call for advances in miniaturized power sources for micro/nano-scale systems. Nanofluidic channels have received great attention as promising high-power-density substitutes for ion exchange membranes for use in energy harvesting from ambient ionic concentration gradient, namely reverse electrodialysis. This paper proposes the nanofluidic crystal (NFC), of packed nanoparticles in micro-meter-sized confined space, as a facile, high-efficiency and high-power-density scaling-up scheme for energy harvesting by nanofluidic reverse electrodialysis (NRED). Obtained from the self-assembly of nanoparticles in a micropore, the NFC forms an ion-selective network with enormous nanochannels due to electrical double-layer overlap in the nanoparticle interstices. As a proof-of-concept demonstration, a maximum efficiency of 42.3 ± 1.84%, a maximum power density of 2.82 ± 0.22 W m(-2), and a maximum output power of 1.17 ± 0.09 nW/unit (nearly three orders of magnitude of amplification compared to other NREDs) were achieved in our prototype cell, which was prepared within 30 min. The current NFC-based prototype cell can be parallelized and cascaded to achieve the desired output power and open circuit voltage. This NFC-based scaling-up scheme for energy harvesting based on NRED is promising for the building of self-powered micro/nano-scale systems.

  19. Nanofluidic crystal: a facile, high-efficiency and high-power-density scaling up scheme for energy harvesting based on nanofluidic reverse electrodialysis

    NASA Astrophysics Data System (ADS)

    Ouyang, Wei; Wang, Wei; Zhang, Haixia; Wu, Wengang; Li, Zhihong

    2013-08-01

    The great advances in nanotechnology call for advances in miniaturized power sources for micro/nano-scale systems. Nanofluidic channels have received great attention as promising high-power-density substitutes for ion exchange membranes for use in energy harvesting from ambient ionic concentration gradient, namely reverse electrodialysis. This paper proposes the nanofluidic crystal (NFC), of packed nanoparticles in micro-meter-sized confined space, as a facile, high-efficiency and high-power-density scaling-up scheme for energy harvesting by nanofluidic reverse electrodialysis (NRED). Obtained from the self-assembly of nanoparticles in a micropore, the NFC forms an ion-selective network with enormous nanochannels due to electrical double-layer overlap in the nanoparticle interstices. As a proof-of-concept demonstration, a maximum efficiency of 42.3 ± 1.84%, a maximum power density of 2.82 ± 0.22 W m-2, and a maximum output power of 1.17 ± 0.09 nW/unit (nearly three orders of magnitude of amplification compared to other NREDs) were achieved in our prototype cell, which was prepared within 30 min. The current NFC-based prototype cell can be parallelized and cascaded to achieve the desired output power and open circuit voltage. This NFC-based scaling-up scheme for energy harvesting based on NRED is promising for the building of self-powered micro/nano-scale systems.

  20. Efficient phosphorus management practices in the Everglades Agricultural Area

    NASA Astrophysics Data System (ADS)

    Bhadha, J. H.; Lang, T. A.; Daroub, S. H.; Alvarez, O.; Tootoonchi, M.; Capasso, J.

    2016-12-01

    In the 450,000 acres of the Everglades Agricultural Area (EAA) of South Florida, farming practices have long been mindful of phosphorus (P) management as it relates to sufficiency and efficiency of P utilization. Over two decades of P best management practices have resulted in 3001 metric-ton of P load reduction from the EAA to downstream ecosystems. During the summer, more than 50,000 acres of fallow sugarcane land is available for rice production. The net value of growing flooded rice in the EAA as a rotational crop with sugarcane far exceeds its monetary return. Soil conservation, improvement in tilth and P load reduction are only some of the benefits. With no P fertilizer applied, a two-year field trial on flooded rice showed improved outflow P concentrations by up to 40% as a result of particulate setting and plant P uptake. Harvested whole grain rice can effectively remove a significant amount of P from a rice field per growing season. In parts of the EAA where soils are sandy, the application of using locally derived organic amendments as potential P fertilizer has gained interest over the past few years. The use of local agricultural and urban organic residues as amendments in sandy soils of South Florida provide options to enhance soil properties and improve sugarcane yields, while reducing waste and harmful effects of agricultural production on the environment. A lysimeter study conducted to determine the effect of mill ash and three types of biochar (rice hulls, yard waste, horse bedding) on sugarcane yields, soil properties, and drainage water quality in sandy soils showed that mill ash and rice hull biochar increased soil TP, Mehlich 3-P (M3-P), and cation exchange capacity (CEC) compared to the control. TP and M3-P content remained constant after 9 months, CEC showed a significant increase over time with rich hull biochar addition. Future projects include the utilization of aquatic vegetation, such as chara and southern naiad as bio-filters in farm

  1. A New Tool for Effective and Efficient Project Management

    SciTech Connect

    Willett, Jesse A

    2011-12-01

    Organizations routinely handle thousands of projects per year, and it is difficult to manage all these projects concurrently. Too often, projects do not get the attention they need when they need it. Management inattention can lead to late projects or projects with less than desirable content and/or deliverables. This paper discusses the application of Visual Project Management (VPM) as a method to track and manage projects. The VPM approach proved to be a powerful management tool without the overhead and restrictions of traditional management methods.

  2. A new postoperative management scheme for preventing sacral pressure sores in patients with spinal cord injuries.

    PubMed

    Kato, H; Inoue, T; Torii, S

    1998-01-01

    Although the reliability of pressure sore surgery has improved with the advent of many different types of flaps, it is well known that the recurrence rate of pressure sores is still remarkably high in spinal cord-injured patients. This article reports the very low relapse rate of postsurgical pressure sores using air mattresses, which also helps relieve manpower requirements for care. We measured interface pressures at the sacrum for 18 spinal cord-injured patients with a ROHO air mattress (ROHO International, Inc, Belleville, IL). Based on the results, we used this mattress immediately after surgery for 19 spinal cord-injured patients with sacral pressure sores. Minimal repositioning was performed for each patient during the hospital stay. Minimal repositioning was similarly performed at home. All pressure sores healed, regardless of the type of surgical procedure, size, and degree of sore. No relapse has been found, with an average of 33.4 months after surgery. With this management, we could achieve a very low recurrence rate, require less manpower for postoperative management, as well as minimize stress for the patients.

  3. The Opals Data Manager - Efficient Data Management for Processing Large Airborne Laser Scanning Projects

    NASA Astrophysics Data System (ADS)

    Otepka, J.; Mandlburger, G.; Karel, W.

    2012-07-01

    The fast measurement rate of today's Airborne Laser Scanners results in billions of points for single ALS projects. Efficient algorithms and data management methods are, therefore, a precondition for successful project handling. The software package OPALS (Orientation and Processing of Airborne Laser Scanning data) was especially designed to meet those criteria. Central core of the package is the OPALS Data Manager (ODM). It provides both, fast spatial access to huge point clouds, as well as a flexible attribute schema to store additional point related quantities. Concepts of the spatial data organization and implementation details about the attribute handling are presented. Additionally, design rationales of the ODM, its file format and the system performance are described.

  4. A Electronic Voting Scheme Achieved by Using Quantum Proxy Signature

    NASA Astrophysics Data System (ADS)

    Cao, Hai-Jing; Ding, Li-Yuan; Yu, Yao-Feng; Li, Peng-Fei

    2016-09-01

    In this paper, we propose a new electronic voting scheme using Bell entangled states as quantum channels. This scheme is based on quantum proxy signature. The voter Alice, vote management center Bob, teller Charlie and scrutineer Diana only perform single particle measurement to realize the electronic voting process. So the scheme reduces the technical difficulty and increases operation efficiency. It can be easily realized. We use quantum key distribution and one-time pad to guarantee its unconditional security. The scheme uses the physical characteristics of quantum mechanics to guarantee its anonymity, verifiability, unforgetability and undeniability.

  5. Managed care and technical efficiency in outpatient substance abuse treatment units.

    PubMed

    Alexander, J A; Wheeler, J R; Nahra, T A; Lemak, C H

    1998-11-01

    This article examines (1) the extent to which managed care participation is associated with technical efficiency in outpatient substance abuse treatment (OSAT) organizations and (2) the contributions of specific managed care practices as well as other organizational, financial, and environmental attributes to technical efficiency in these organizations. Data are from a nationally representative sample survey of OSAT organizations conducted in 1995. Technical efficiency is modeled using data envelopment analysis. Overall, there were few significant associations between managed care dimensions and technical efficiency in outpatient treatment organizations. Only one managed care oversight procedure, the imposition of sanctions by managed care firms, was significantly associated with relative efficiency of these provider organizations. However, several organizational factors were associated with the relative level of efficiency including hospital affiliation, mental health center affiliation, JCAHO accreditation, receipt of lump sum revenues, methadone treatment modality, percentage clients unemployed, and percentage clients who abuse multiple drugs.

  6. Decision support models for economically efficient integrated forest management

    Treesearch

    Hans R. Zuuring; Judy M. Troutwine; Greg J. Jones; Janet Sullivan

    2005-01-01

    Forest managers are challenged to fulfill conflicting social, biological, and commodity production objectives. To wisely use available, scarce resources for management activities, it is not enough to consider short term costs and effects of management (fuel reduction, planting, or other forest treatments). Long term tactical, spatial and temporal planning is needed to...

  7. Supporting public involvement in research design and grant development: a case study of a public involvement award scheme managed by a National Institute for Health Research (NIHR) Research Design Service (RDS).

    PubMed

    Boote, Jonathan D; Twiddy, Maureen; Baird, Wendy; Birks, Yvonne; Clarke, Clare; Beever, Daniel

    2015-10-01

    It is good practice for the public to be involved in developing health research. Resources should be available for researchers to fund the involvement of the public in the development of their grants. To describe a funding award scheme to support public involvement in grant development, managed by an NIHR Research Design Service (RDS). Case examples of how the award contributed to successful grant applications and findings from a recent evaluation of the scheme are presented. A case study of resource provision to support public involvement activities in one region of England. University and NHS-based researchers, and members of the public. Between 2009 and 2012, the RDS approved 45 public involvement funding awards (totalling nearly £19,000). These awards contributed to 27 submitted applications at the time of writing, of which 11 were successful (totalling over £7.5 million). The evaluation revealed difficulties encountered by some researchers when involving the public in grant development, which led to suggestions about how the scheme could be improved. This award scheme represents an efficient method of providing researchers with resources to involve the public in grant development and would appear to represent good value for money. © 2013 John Wiley & Sons Ltd.

  8. Efficient hollow fiber compression scheme for generating multi-mJ, carrier-envelope phase stable, sub-5 fs pulses

    NASA Astrophysics Data System (ADS)

    Chen, X.; Malvache, A.; Ricci, A.; Jullien, A.; Lopez-Martens, R.

    2011-01-01

    We show that a standard hollow-core fiber (HCF) compressor device can be used to efficiently compress multi-mJ energy laser pulses down to few-cycle duration, when seeded with linearly chirped, circularly polarized pulses. With this approach, we routinely generate carrier-envelope phase (CEP)-locked, 1.6 mJ, 4.8 fs pulses using only 3 mJ, 25 fs pulses as the seed.

  9. Transformations of Nitrogen from Secondary Treated Wastewater when Infiltrated in Managed Aquifer Recharge Schemes

    NASA Astrophysics Data System (ADS)

    Silver, Matthew; Wefer-Roehl, Annette; Kübeck, Christine; Schüth, Christoph

    2016-04-01

    The EU FP7 project MARSOL seeks to address water scarcity challenges in arid regions, where managed aquifer recharge (MAR) is an upcoming technology to recharge depleted aquifers using alternative water sources. Within this framework, we conduct column experiments to investigate transformations of nitrogen species when secondary treated wastewater (STWW) is infiltrated through two natural soils being considered for managed aquifer recharge. The soils vary considerably in organic matter content, with total organic matter determined by loss on ignition of 6.8 and 2.9 percent by mass for Soil 1 and Soil 2, respectively. Ammonium (NH4+) concentrations as high as 8.6 mg/L have been measured in pore water samples from Soil #1, indicating that ammonium could be a contaminant of concern in MAR applications using STWW, with consideration of the EU limit of 0.5 mg/L for NH4+. The two forms of nitrogen with the highest concentrations in the secondary treated wastewater are nitrate (NO3-) and dissolved organic nitrogen (DON). In water samples taken from the soil columns, a mass balance of measured ions shows a deficit of nitrogen in ionic form in the upper to middle depths of the soil, suggesting the presence of unmeasured species. These are likely nitrous oxide or dinitrogen gas, which would signify that denitrification is occurring. Measurements of N2O from water samples will verify its presence and spatial variation. The ammonium concentrations increase slowly in the upper parts of the soil but then increase more sharply at greater depth, after NO3- is depleted, suggesting that DON is the source of the produced NH4+. The production of NH4+ is presumed to be facilitated microbiologically. It is hypothesized that at higher organic carbon to total nitrogen (C:N) ratios, more NH4+ will be formed. To test this, in the experiments with Soil #2, three different inflow waters are used, listed in order of decreasing C:N ratio: STWW, STWW with NO3- added to a concentration of 80 mg

  10. A Memory-Efficient Deterministic Finite Automaton-Based Bit-Split String Matching Scheme Using Pattern Uniqueness in Deep Packet Inspection

    PubMed Central

    Kim, HyunJin; Choi, Kang-Il; Choi, Sang-Il

    2015-01-01

    This paper proposes a memory-efficient bit-split string matching scheme for deep packet inspection (DPI). When the number of target patterns becomes large, the memory requirements of the string matching engine become a critical issue. The proposed string matching scheme reduces the memory requirements using the uniqueness of the target patterns in the deterministic finite automaton (DFA)-based bit-split string matching. The pattern grouping extracts a set of unique patterns from the target patterns. In the set of unique patterns, a pattern is not the suffix of any other patterns. Therefore, in the DFA constructed with the set of unique patterns, when only one pattern can be matched in an output state. In the bit-split string matching, multiple finite-state machine (FSM) tiles with several input bit groups are adopted in order to reduce the number of stored state transitions. However, the memory requirements for storing the matching vectors can be large because each bit in the matching vector is used to identify whether its own pattern is matched or not. In our research, the proposed pattern grouping is applied to the multiple FSM tiles in the bit-split string matching. For the set of unique patterns, the memory-based bit-split string matching engine stores only the pattern match index for each state to indicate the match with its own unique pattern. Therefore, the memory requirements are significantly decreased by not storing the matching vectors in the string matchers for the set of unique patterns. The experimental results show that the proposed string matching scheme can reduce the storage cost significantly compared to the previous bit-split string matching methods. PMID:25938779

  11. Knowledge management for efficient quantitative analyses during regulatory reviews.

    PubMed

    Krudys, Kevin; Li, Fang; Florian, Jeffry; Tornoe, Christoffer; Chen, Ying; Bhattaram, Atul; Jadhav, Pravin; Neal, Lauren; Wang, Yaning; Gobburu, Joga; Lee, Peter I D

    2011-11-01

    Knowledge management comprises the strategies and methods employed to generate and leverage knowledge within an organization. This report outlines the activities within the Division of Pharmacometrics at the US FDA to effectively manage knowledge with the ultimate goal of improving drug development and advancing public health. The infrastructure required for pharmacometric knowledge management includes provisions for data standards, queryable databases, libraries of modeling tools, archiving of analysis results and reporting templates for effective communication. Two examples of knowledge management systems developed within the Division of Pharmacometrics are used to illustrate these principles. The benefits of sound knowledge management include increased productivity, allowing reviewers to focus on research questions spanning new drug applications, such as improved trial design and biomarker development. The future of knowledge management depends on the collaboration between the FDA and industry to implement data and model standards to enhance sharing and dissemination of knowledge.

  12. Dermatology practice management assures practice development and efficiency.

    PubMed

    Wagener, D L

    2000-09-01

    This article provides an overview of the disciplines involved in managing a dermatology practice today. Several key management processes, including strategic planning, financial analysis, advertising and public relations, information systems management, and compliance program development and monitoring are addressed. This article explores several possible tactics that can be used to help guide your practice in the right direction without overtaxing your resources. Also offered are possible solutions for creating an organization that is poised for success, and a management team capable of steering the practice through the sea of change ahead.

  13. HVAC & Building Management Control System Energy Efficiency Replacements

    SciTech Connect

    Hernandez, Adriana

    2012-09-21

    The project objective was the replacement of an aging, un-repairable HVAC system which has grown inefficient and a huge energy consumer with low energy and efficient HVAC units, and installation of energy efficient building control technologies at City's YMCA Community Center.

  14. Single Cell Proteolytic Assays to Investigate Cancer Clonal Heterogeneity and Cell Dynamics Using an Efficient Cell Loading Scheme

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Chih; Cheng, Yu-Heng; Ingram, Patrick; Yoon, Euisik

    2016-06-01

    Proteolytic degradation of the extracellular matrix (ECM) is critical in cancer invasion, and recent work suggests that heterogeneous cancer populations cooperate in this process. Despite the importance of cell heterogeneity, conventional proteolytic assays measure average activity, requiring thousands of cells and providing limited information about heterogeneity and dynamics. Here, we developed a microfluidic platform that provides high-efficiency cell loading and simple valveless isolation, so the proteolytic activity of a small sample (10–100 cells) can be easily characterized. Combined with a single cell derived (clonal) sphere formation platform, we have successfully demonstrated the importance of microenvironmental cues for proteolytic activity and also investigated the difference between clones. Furthermore, the platform allows monitoring single cells at multiple time points, unveiling different cancer cell line dynamics in proteolytic activity. The presented tool facilitates single cell proteolytic analysis using small samples, and our findings illuminate the heterogeneous and dynamic nature of proteolytic activity.

  15. Single Cell Proteolytic Assays to Investigate Cancer Clonal Heterogeneity and Cell Dynamics Using an Efficient Cell Loading Scheme

    PubMed Central

    Chen, Yu-Chih; Cheng, Yu-Heng; Ingram, Patrick; Yoon, Euisik

    2016-01-01

    Proteolytic degradation of the extracellular matrix (ECM) is critical in cancer invasion, and recent work suggests that heterogeneous cancer populations cooperate in this process. Despite the importance of cell heterogeneity, conventional proteolytic assays measure average activity, requiring thousands of cells and providing limited information about heterogeneity and dynamics. Here, we developed a microfluidic platform that provides high-efficiency cell loading and simple valveless isolation, so the proteolytic activity of a small sample (10–100 cells) can be easily characterized. Combined with a single cell derived (clonal) sphere formation platform, we have successfully demonstrated the importance of microenvironmental cues for proteolytic activity and also investigated the difference between clones. Furthermore, the platform allows monitoring single cells at multiple time points, unveiling different cancer cell line dynamics in proteolytic activity. The presented tool facilitates single cell proteolytic analysis using small samples, and our findings illuminate the heterogeneous and dynamic nature of proteolytic activity. PMID:27283981

  16. Efficient ab initio schemes for finding thermodynamically stable and metastable atomic structures: benchmark of cascade genetic algorithms

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Saswata; Levchenko, Sergey V.; Ghiringhelli, Luca M.; Scheffler, Matthias

    2014-12-01

    A first principles-based methodology for efficiently and accurately finding thermodynamically stable and metastable atomic structures is introduced and benchmarked. The approach is demonstrated for gas-phase metal-oxide clusters in thermodynamic equilibrium with a reactive (oxygen) atmosphere at finite pressure and temperature. It consists of two steps. First, the potential-energy surface is scanned by means of a global-optimization technique, i.e., a massive-parallel first-principles cascade genetic algorithm for which the choice of all parameters is validated against higher-level methods. In particular, we validate (a) the criteria for selection and combination of structures used for the assemblage of new candidate structures, and (b) the choice of the exchange-correlation functional. The selection criteria are validated against a fully unbiased method: replica-exchange molecular dynamics. Our choice of exchange-correlation functional, the van der Waals-corrected PBE0 hybrid functional, is justified by comparisons up to the highest level currently achievable within density-functional theory, i.e., the renormalized second-order perturbation theory. In the second step, the low-energy structures are analyzed by means of ab initio atomistic thermodynamics in order to determine compositions and structures that minimize the Gibbs free energy at given temperature and pressure of the reactive atmosphere.

  17. Non-antireflective scheme for efficiency enhancement of Cu(In,Ga)Se2 nanotip array solar cells.

    PubMed

    Liao, Yu-Kuang; Wang, Yi-Chung; Yen, Yu-Ting; Chen, Chia-Hsiang; Hsieh, Dan-Hua; Chen, Shih-Chen; Lee, Chia-Yu; Lai, Chih-Chung; Kuo, Wei-Chen; Juang, Jenh-Yi; Wu, Kaung-Hsiung; Cheng, Shun-Jen; Lai, Chih-Huang; Lai, Fang-I; Kuo, Shou-Yi; Kuo, Hao-Chung; Chueh, Yu-Lun

    2013-08-27

    We present systematic works in characterization of CIGS nanotip arrays (CIGS NTRs). CIGS NTRs are obtained by a one-step ion-milling process by a direct-sputtering process of CIGS thin films (CIGS TF) without a postselenization process. At the surface of CIGS NTRs, a region extending to 100 nm in depth with a lower copper concentration compared to that of CIGS TF has been discovered. After KCN washing, removal of secondary phases can be achieved and a layer with abundant copper vacancy (V(Cu)) was left. Such compositional changes can be a benefit for a CIGS solar cell by promoting formation of Cd-occupied Cu sites (Cd(Cu)) at the CdS/CIGS interface and creates a type-inversion layer to enhance interface passivation and carrier extraction. The raised V(Cu) concentration and enhanced Cd diffusion in CIGS NTRs have been verified by energy dispersive spectrometry. Strengthened adhesion of Al:ZnO (AZO) thin film on CIGS NTRs capped with CdS has also been observed in SEM images and can explain the suppressed series resistance of the device with CIGS NTRs. Those improvements in electrical characteristics are the main factors for efficiency enhancement rather than antireflection.

  18. Towards a standard licensing scheme for the access and use of satellite earth observation data for disaster management

    NASA Astrophysics Data System (ADS)

    Clark, Nathan E.

    2017-10-01

    This paper explores from the view of the data recipient and user the complexities of creating a common licensing scheme for the access and use of satellite earth observation (EO) data in international disaster management (DM) activities. EO data contributions in major disaster events often involve numerous data providers with separate licensing mechanisms for controlling the access, uses, and distribution of data by the end users. A lack of standardization among the terminology, wording, and conditions within these licenses creates a complex legal environment for users, and often prevents them from using, sharing and combining datasets in an effective and timely manner. It also creates uncertainty among data providers as to the types of licensing controls that should be applied in disaster scenarios. This paper builds from an ongoing comparative analysis of the common and conflicting conditions among data licenses that must be addressed in order to facilitate easier access and use of EO data within the DM sector and offers recommendations towards the alignment of the structural and technical aspects of licenses among data providers.

  19. Systematic review of the effectiveness and cost-effectiveness of weight management schemes for the under fives: a short report.

    PubMed

    Bond, M; Wyatt, K; Lloyd, J; Welch, K; Taylor, R

    2009-12-01

    To search for, review and synthesise studies of the effectiveness and cost-effectiveness of weight management schemes for the under fives. MEDLINE [Ovid], MEDLINE In-Process [Ovid], EMBASE [Ovid], CAB [Ovid], Health Management Information Consortium [Ovid], The Cochrane Database of Systematic Reviews, Cochrane Register of Controlled Trials, Science Citation Index Expanded [Web of Science], Conference Proceedings Citation Index [The Web of Science], Database of Abstract Reviews [CRD; Centre for Reviews and Dissemination], HTA [CRD], PsycINFO [Ebsco], NHS CRD. These databases were searched from 1990 to February 2009. Supplementary internet searches were additionally conducted. Relevant clinical effectiveness studies were identified in two stages. Titles and abstracts returned by the search strategy were examined independently by three researchers and screened for possible inclusion. Disagreements were resolved by discussion. Full texts of the identified studies were obtained. Three researchers examined these independently for inclusion or exclusion, and disagreements were again resolved by discussion. One of the randomised controlled trials (RCTs) was from the UK. It measured the effects of a physical activity intervention for children in nurseries combined with home-based health education for their parents; this was compared to usual care. The main outcome measure was body mass index (BMI); secondary measures were weight and physical activity. At the 12-month follow-up, no statistically significant differences were found between the groups on any measure. However, a trend, favouring the intervention, was found for BMI and weight. The other two RCTs were from the USA. The larger trial investigated the effects of a combined preschool and home intervention in African American and Latino communities. Nutrition education and physical activity programmes were aimed at under fives in preschool. The home component consisted of related health education and homework for the

  20. Relaxation schemes for Chebyshev spectral multigrid methods

    NASA Technical Reports Server (NTRS)

    Kang, Yimin; Fulton, Scott R.

    1993-01-01

    Two relaxation schemes for Chebyshev spectral multigrid methods are presented for elliptic equations with Dirichlet boundary conditions. The first scheme is a pointwise-preconditioned Richardson relaxation scheme and the second is a line relaxation scheme. The line relaxation scheme provides an efficient and relatively simple approach for solving two-dimensional spectral equations. Numerical examples and comparisons with other methods are given.

  1. Novel AgI-decorated β-Bi₂O₃ nanosheet heterostructured Z-scheme photocatalysts for efficient degradation of organic pollutants with enhanced performance.

    PubMed

    Zhang, Zhengyuan; Jiang, Deli; Xing, Chaosheng; Chen, Linlin; Chen, Min; He, Minqiang

    2015-07-07

    The low photocatalytic activity of single semiconductor photocatalysts mainly originates from their fast recombination of photogenerated electron-hole pairs. Constructing nanosheet-based composite photocatalysts is an effective way to enhance the charge separation efficiency of photogenerated electron-hole pairs. In this work, AgI-decorated β-Bi2O3 nanosheet heterostructured photocatalysts were prepared by a facile method. The as-obtained AgI/β-Bi2O3 heterostructures exhibited enhanced visible-light-driven photocatalytic activity towards the degradation of methyl orange (MO) and tetracycline hydrochloride (TC) in aqueous solution. The optimum photocatalytic activity of 20%-AgI/β-Bi2O3 for the degradation of MO was about 4.1 and 6.2 times higher than that of AgI and β-Bi2O3. The photocatalytic activity enhancement of AgI/β-Bi2O3 heterostructures could be ascribed to the formation of a Z-scheme system, which results in the efficient space separation of photo-induced charge carriers.

  2. Efficient Assessment of the Environment for Integral Urban Water Management

    NASA Astrophysics Data System (ADS)

    Rost, Grit; Londong, Jörg

    2015-04-01

    Introduction: Sustainable water supply and sanitation is fundamental, especially in countries that are also particularly vulnerable to water-related problems. The Integrated Water Resources Management (IWRM) approach makes sure that water management is organised in a transdisciplinary way taking into account the river basin, the hydrologic system and the appendant organisation like culture, law and economics. The main objective of IWRM is the sustainable organisation of water resources quality and quantity (GWP and INBO 2009). However there are more important targets in sustainable use of water resources. New sanitation systems are focussing on adding value and maintaining essential resources in circular flow. Focussing on material fluxes can contribute on water quality, food security, sustainable use of renewable energy, adaption on water scarcity and also on rising water and sanitation demand because of rapid urban and suburban growth (Price and Vojinović 2011; Rost et al 2013; Stäudel et al 2014). Problem: There are several planning tools for IWRM as well as for urban water management. But to complete the IWRM approach for the resource oriented concept a systematic assessment tool is missing. The assessment of crucial indicators obviously requires a lot of data from different subjects/disciplines, in different scales of detail and in different accuracy and in data acquisition (Karthe et al 2014). On the one hand there will be data abundance and on the other hand the data can be unavailable or unfeasible for example because of scale and specification(Rost et al 2013). Such a complex integrated concept requires a clearly worked out structure for the way of managing and priority setting. Purpose: To get systematic in the complex planning process the toolbox model is going to develop. The assessment of the environmental screening (one part of the toolbox) is going to be presented in this paper. The first step of assessment leans on the assertion that each of the

  3. Efficient Management of Fruit Pests by Pheromone Nanogels

    PubMed Central

    Bhagat, Deepa; Samanta, Suman K.; Bhattacharya, Santanu

    2013-01-01

    Environment-friendly management of fruit flies involving pheromones is useful in reducing the undesirable pest populations responsible for decreasing the yield and the crop quality. A nanogel has been prepared from a pheromone, methyl eugenol (ME) using a low-molecular mass gelator. This was very stable at open ambient conditions and slowed down the evaporation of pheromone significantly. This enabled its easy handling and transportation without refrigeration, and reduction in the frequency of pheromone recharging in the orchard. Notably the involvement of the nano-gelled pheromone brought about an effective management of Bactrocera dorsalis, a prevalent harmful pest for a number of fruits including guava. Thus a simple, practical and low cost green chemical approach is developed that has a significant potential for crop protection, long lasting residual activity, excellent efficacy and favorable safety profiles. This makes the present invention well-suited for pest management in a variety of crops. PMID:23416455

  4. The impact of New Public Management on efficiency: an analysis of Madrid's hospitals.

    PubMed

    Alonso, José M; Clifton, Judith; Díaz-Fuentes, Daniel

    2015-03-01

    Madrid has recently become the site of one of the most controversial cases of public healthcare reform in the European Union. Despite the fact that the introduction of New Public Management (NPM) into Madrid hospitals has been vigorous, little scholarship has been done to test whether NPM actually led to technical efficiency. This paper is one of the first attempts to do so. We deploy a bootstrapped data envelopment analysis to compare efficiency scores in traditionally managed hospitals and those operating with new management formulas. We do not find evidence that NPM hospitals are more efficient than traditionally managed ones. Moreover, our results suggest that what actually matters may be the management itself, rather than the management model.

  5. Integrated energy management study. Energy efficient transport program

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The Integrated Energy Management (IEM) Study investigated the practicality and feasibility of a closed-loop energy management system for transport aircraft. The study involved: (1) instrumentation and collection of in-flight data for a United Airlines 727-200 flying 80 revenue flights throughout the United Airlines network,(2) analysis of the in-flight data to select representative city pairs and establish operational procedures employed in flying a reference flight profile, (3) simulation of the reference profile in a fast-time model to verify the model and establish performance values against which to measure IEM benefits, (4) development of IEM algorithms, and (5) assessment of the IEM concept.

  6. Managing carbon emissions in China through building energy efficiency.

    PubMed

    Li, Jun; Colombier, Michel

    2009-06-01

    This paper attempts to analyse the role of building energy efficiency (BEE) in China in addressing climate change mitigation. It provides an analysis of the current situation and future prospects for the adoption of BEE technologies in Chinese cities. It outlines the economic and institutional barriers to large-scale deployment of the sustainable, low-carbon, and even carbon-free construction techniques. Based on a comprehensive overview of energy demand characteristics and development trends driven by economic and demographic growth, different policy tools for cost-effective CO(2) emission reduction in the Chinese construction sector are described. We propose a comprehensive approach combining building design and construction, and the urban planning and building material industries, in order to drastically improve BEE during this period of rapid urban development. A coherent institutional framework needs to be established to ensure the implementation of efficiency policies. Regulatory and incentive options should be integrated into the policy portfolios of BEE to minimise the efficiency gap and to realise sizeable carbon emissions cuts in the next decades. We analyse in detail several policies and instruments, and formulate relevant policy proposals fostering low-carbon construction technology in China. Specifically, Our analysis shows that improving building energy efficiency can generate considerable carbon emissions reduction credits with competitive price under the CDM framework.

  7. Adaptive Voltage Management Enabling Energy Efficiency in Nanoscale Integrated Circuits

    NASA Astrophysics Data System (ADS)

    Shapiro, Alexander E.

    Battery powered devices emphasize energy efficiency in modern sub-22 nm CMOS microprocessors rendering classic power reduction solutions not sufficient. Classical solutions that reduce power consumption in high performance integrated circuits are superseded with novel and enhanced power reduction techniques to enable the greater energy efficiency desired in modern microprocessors and emerging mobile platforms. Dynamic power consumption is reduced by operating over a wide range of supply voltages. This region of operation is enabled by a high speed and power efficient level shifter which translates low voltage digital signals to higher voltages (and vice versa), a key component that enables communication among circuits operating at different voltage levels. Additionally, optimizing the wide supply voltage range of signals propagating across long interconnect enables greater energy savings. A closed-form delay model supporting wide voltage range is developed to enable this capability. The model supports an ultra-wide voltage range from nominal voltages to subthreshold voltages, and a wide range of repeater sizes. To mitigate the drawback of lower operating speed at reduced supply voltages, the high performance exhibited by MOS current mode logic technology is exploited. High performance and energy efficient circuits are enabled by combining this logic style with power efficient near threshold circuits. Many-core systems that operate at high frequencies and process highly parallel workloads benefit from this combination of MCML with NTC. Due to aggressive scaling, static power consumption can in some cases overshadow dynamic power. Techniques to lower leakage power have therefore become an important objective in modern microprocessors. To address this issue, an adaptive power gating technique is proposed. This technique utilizes high levels of granularity to save additional leakage power when a circuit is active as opposed to standard power gating that saves static

  8. Economic efficiency of fire management programs at six National Forests

    Treesearch

    Dennis L. Schweitzer; Ernest V. Andersen; Thomas J. Mills

    1982-01-01

    Two components of fire management programs were analyzed at these Forests: Francis Marion (South Carolina), Huron-Manistee (Michigan), San Bernardino (California), Tonto (Arizona), and Deschutes and Willamette (Oregon). Initial attack and aviation operations were evaluated by the criterion of minimizing the program cost plus the net value change of resource outputs and...

  9. Institutional Values of Managed Mental Health Care: Efficiency or Oppression?

    ERIC Educational Resources Information Center

    Wilcoxon, S. Allen; Magnuson, Sandy; Norem, Ken

    2008-01-01

    The authors suggest that many managed mental health care (MMHC) practices have oppressive effects on members of cultural and ethnic minority groups. They examine the dissonance between institutional practices and cultural traditions that reflect insensitivity and forced conformity, particularly regarding time, pace, and intervention uniformity as…

  10. Institutional Values of Managed Mental Health Care: Efficiency or Oppression?

    ERIC Educational Resources Information Center

    Wilcoxon, S. Allen; Magnuson, Sandy; Norem, Ken

    2008-01-01

    The authors suggest that many managed mental health care (MMHC) practices have oppressive effects on members of cultural and ethnic minority groups. They examine the dissonance between institutional practices and cultural traditions that reflect insensitivity and forced conformity, particularly regarding time, pace, and intervention uniformity as…

  11. Efficiency Mode of Energy Management based on Optimal Flight Path

    NASA Astrophysics Data System (ADS)

    Yang, Ling-xiao

    2016-07-01

    One new method of searching the optimal flight path in target function is put forward, which is applied to energy section for reentry flight vehicle, and the optimal flight path in which the energy is managed to decline rapidly, is settled by this design. The research for energy management is meaningful for engineering, it can also improve the applicability and flexibility for vehicle. The angle-of-attack and the bank angle are used to regulate energy and range at unpowered reentry flight as control variables. Firstly, the angle-of-attack section for minimum lift-to-drag ratio is ensured by the relation of range and lift-to-drag ratio. Secondly, build the secure boundary for flight corridor by restrictions in flight. Thirdly, the D-e section is optimized for energy expending in corridor by the influencing rule of the D-e section and range. Finally, compare this design method with the traditional Pseudo-spectral method. Moreover, energy-managing is achieved by cooperating lateral motion, and the optimized D-e section is tracked to prove the practicability of programming flight path with energy management.

  12. An Efficient, Semi-implicit Pressure-based Scheme Employing a High-resolution Finitie Element Method for Simulating Transient and Steady, Inviscid and Viscous, Compressible Flows on Unstructured Grids

    SciTech Connect

    Richard C. Martineau; Ray A. Berry

    2003-04-01

    equation in the PCICE-FEM scheme is provided with sufficient internal energy information to avoid iteration. The ability of the PCICE-FEM scheme to accurately and efficiently simulate a wide variety of inviscid and viscous compressible flows is demonstrated here.

  13. A Comparative Study of Mindfulness Efficiency Based on Islamic-Spiritual Schemes and Group Cognitive Behavioral Therapy on Reduction of Anxiety and Depression in Pregnant Women

    PubMed Central

    Aslami, Elahe; Alipour, Ahmad; Najib, Fatemeh Sadat; Aghayosefi, Alireza

    2017-01-01

    ABSTRACT Background: Anxiety and depression during the pregnancy period are among the factors affecting the pregnancy undesirable outcomes and delivery. One way of controlling anxiety and depression is mindfulness and cognitive behavioral therapy. The purpose of this study was to compare the efficiency of mindfulness based on the Islamic-spiritual schemas and group cognitive behavioral therapy on reduction of anxiety and depression in pregnant women. Methods: The research design was semi-experimental in the form of pretest-posttest using a control group. Among the pregnant women in the 16th to 32nd weeks of pregnancy who referred to the health center, 30 pregnant women with high anxiety level and 30 pregnant women with high depression participated in the research. Randomly 15 participants with high depression and 15 participants with high anxiety were considered in the intervention group under the treatment of mindfulness based on Islamic-spiritual schemes. In addition, 15 participants with high scores regarding depression and 15 with high scores in anxiety were considered in the other group. .The control group consisted of 15 pregnant women with high anxiety and depression. Beck anxiety-depression questionnaire was used in two steps of pre-test and post-test. Data were analyzed using SPSS, version 20, and P≤0.05 was considered as significant. Results: The results of multivariate analysis of variance test and tracking Tokey test showed that there was a significant difference between the mean scores of anxiety and depression in the two groups of mindfulness based on spiritual- Islamic scheme (P<0.001) and the group of cognitive behavioral therapy with each other (P<0.001) and with the control group(P<0.001). The mean of anxiety and depression scores decreased in the intervention group, but it increased in the control group. Conclusion: Both therapy methods were effective in reduction of anxiety and depression of pregnant women, but the effect of mindfulness based

  14. A PWM Buck Converter With Load-Adaptive Power Transistor Scaling Scheme Using Analog-Digital Hybrid Control for High Energy Efficiency in Implantable Biomedical Systems.

    PubMed

    Park, Sung-Yun; Cho, Jihyun; Lee, Kyuseok; Yoon, Euisik

    2015-12-01

    We report a pulse width modulation (PWM) buck converter that is able to achieve a power conversion efficiency (PCE) of > 80% in light loads 100 μA) for implantable biomedical systems. In order to achieve a high PCE for the given light loads, the buck converter adaptively reconfigures the size of power PMOS and NMOS transistors and their gate drivers in accordance with load currents, while operating at a fixed frequency of 1 MHz. The buck converter employs the analog-digital hybrid control scheme for coarse/fine adjustment of power transistors. The coarse digital control generates an approximate duty cycle necessary for driving a given load and selects an appropriate width of power transistors to minimize redundant power dissipation. The fine analog control provides the final tuning of the duty cycle to compensate for the error from the coarse digital control. The mode switching between the analog and digital controls is accomplished by a mode arbiter which estimates the average of duty cycles for the given load condition from limit cycle oscillations (LCO) induced by coarse adjustment. The fabricated buck converter achieved a peak efficiency of 86.3% at 1.4 mA and > 80% efficiency for a wide range of load conditions from 45 μA to 4.1 mA, while generating 1 V output from 2.5-3.3 V supply. The converter occupies 0.375 mm(2) in 0.18 μm CMOS processes and requires two external components: 1.2 μF capacitor and 6.8 μH inductor.

  15. A comparative signaling cost analysis of Macro Mobility scheme in NEMO (MM-NEMO) with mobility management protocol

    NASA Astrophysics Data System (ADS)

    Islam, Shayla; Abdalla, Aisha H.; Habaebi, Mohamed H.; Latif, Suhaimi A.; Hassan, Wan H.; Hasan, Mohammad K.; Ramli, H. A. M.; Khalifa, Othman O.

    2013-12-01

    NEMO BSP is an upgraded addition to Mobile IPv6 (MIPv6). As MIPv6 and its enhancements (i.e. HMIPv6) possess some limitations like higher handoff latency, packet loss, NEMO BSP also faces all these shortcomings by inheritance. Network Mobility (NEMO) is involved to handle the movement of Mobile Router (MR) and it's Mobile Network Nodes (MNNs) during handoff. Hence it is essential to upgrade the performance of mobility management protocol to obtain continuous session connectivity with lower delay and packet loss in NEMO environment. The completion of handoff process in NEMO BSP usually takes longer period since MR needs to register its single primary care of address (CoA) with home network that may cause performance degradation of the applications running on Mobile Network Nodes. Moreover, when a change in point of attachment of the mobile network is accompanied by a sudden burst of signaling messages, "Signaling Storm" occurs which eventually results in temporary congestion, packet delays or even packet loss. This effect is particularly significant for wireless environment where a wireless link is not as steady as a wired link since bandwidth is relatively limited in wireless link. Hence, providing continuous Internet connection without any interruption through applying multihoming technique and route optimization mechanism in NEMO are becoming the center of attention to the current researchers. In this paper, we propose a handoff cost model to compare the signaling cost of MM-NEMO with NEMO Basic Support Protocol (NEMO BSP) and HMIPv6.The numerical results shows that the signaling cost for the MM-NEMO scheme is about 69.6 % less than the NEMO-BSP and HMIPv6.

  16. DOD Joint Bases: Management Improvements Needed to Achieve Greater Efficiencies

    DTIC Science & Technology

    2012-11-01

    analyzed DOD guidance and data relating to joint basing. We also selected a nonprobability sample of 3 of the 12 joint bases to visit based on several...achieved and guidance and communication related to cost savings and efficiencies. We selected a nonprobability sample of three site visit locations... techniques , and mechanisms that enforce management’s directives are an integral part of an entity’s planning, implementing, reviewing, and

  17. Energy conservation and management system using efficient building automation

    NASA Astrophysics Data System (ADS)

    Ahmed, S. Faiz; Hazry, D.; Tanveer, M. Hassan; Joyo, M. Kamran; Warsi, Faizan A.; Kamarudin, H.; Wan, Khairunizam; Razlan, Zuradzman M.; Shahriman A., B.; Hussain, A. T.

    2015-05-01

    In countries where the demand and supply gap of electricity is huge and the people are forced to endure increasing hours of load shedding, unnecessary consumption of electricity makes matters even worse. So the importance and need for electricity conservation increases exponentially. This paper outlines a step towards the conservation of energy in general and electricity in particular by employing efficient Building Automation technique. It should be noted that by careful designing and implementation of the Building Automation System, up to 30% to 40% of energy consumption can be reduced, which makes a huge difference for energy saving. In this study above mentioned concept is verified by performing experiment on a prototype experimental room and by implementing efficient building automation technique. For the sake of this efficient automation, Programmable Logic Controller (PLC) is employed as a main controller, monitoring various system parameters and controlling appliances as per required. The hardware test run and experimental findings further clarifies and proved the concept. The added advantage of this project is that it can be implemented to both small and medium level domestic homes thus greatly reducing the overall unnecessary load on the Utility provider.

  18. A Regev-Type Fully Homomorphic Encryption Scheme Using Modulus Switching

    PubMed Central

    Chen, Zhigang; Wang, Jian; Song, Xinxia

    2014-01-01

    A critical challenge in a fully homomorphic encryption (FHE) scheme is to manage noise. Modulus switching technique is currently the most efficient noise management technique. When using the modulus switching technique to design and implement a FHE scheme, how to choose concrete parameters is an important step, but to our best knowledge, this step has drawn very little attention to the existing FHE researches in the literature. The contributions of this paper are twofold. On one hand, we propose a function of the lower bound of dimension value in the switching techniques depending on the LWE specific security levels. On the other hand, as a case study, we modify the Brakerski FHE scheme (in Crypto 2012) by using the modulus switching technique. We recommend concrete parameter values of our proposed scheme and provide security analysis. Our result shows that the modified FHE scheme is more efficient than the original Brakerski scheme in the same security level. PMID:25093212

  19. [The diabetes traffic light scheme - development of an instrument for the case management in patients with diabetes mellitus in primary care].

    PubMed

    Chmiel, C; Birnbaum, B; Gensichen, J; Rosemann, T; Frei, A

    2011-11-30

    In order to sustain the continuity and quality of treatment in diabetic primary care patients, it is necessary to introduce structured and regularly performed monitoring system into the practice team. The monitoring aims at early and valid recognition of potential complications resulting from a chronic disease. Ideally the practice nurse is in charge of the case management. The central element of the case management is a colour coded instrument, the diabetes traffic light scheme, by which means the most important clinical parameters and patient adherence can be screened in regular intervals. Additionally, the instrument regulates in-practice communication by means of stratified action plans and enables ideal treatment continuity also in larger teams. The experiences resulting from the development of this diabetes-specific traffic light scheme can be beneficial for the future development of similar instruments in other chronic diseases.

  20. Efficient identity management and access control in cloud environment

    NASA Astrophysics Data System (ADS)

    Gloster, Jonathan

    2013-05-01

    As more enterprises are enticed to move data to a cloud environment to enhance data sharing and reduce operating costs by exploiting shared resources, concerns have risen over the ability to secure information within the cloud. This paper examines how a traditional Identity and Access Control (IDAM) architecture can be adapted to address security concerns of a cloud environment. We propose changing the paradigm of IDAM form a pure trust model to a risk based model will enable information to be protected securely in a cloud environment without impacting efficiencies of cloud environments.

  1. Pareto Efficient Policy for Supervisory Power Management Control

    SciTech Connect

    Malikopoulos, Andreas

    2015-01-01

    n this paper we address the problem of online optimization of the supervisory power management control in parallel hybrid electric vehicles (HEVs). We model HEV opera- tion as a controlled Markov chain using the long-run expected average cost per unit time criterion, and we show that the control policy yielding the Pareto optimal solution minimizes the average cost criterion online. The effectiveness of the proposed solution is validated through simulation and compared to the solution derived with dynamic programming using the average cost criterion.

  2. An approach to efficient mobility management in intelligent networks

    NASA Technical Reports Server (NTRS)

    Murthy, K. M. S.

    1995-01-01

    Providing personal communication systems supporting full mobility require intelligent networks for tracking mobile users and facilitating outgoing and incoming calls over different physical and network environments. In realizing the intelligent network functionalities, databases play a major role. Currently proposed network architectures envision using the SS7-based signaling network for linking these DB's and also for interconnecting DB's with switches. If the network has to support ubiquitous, seamless mobile services, then it has to support additionally mobile application parts, viz., mobile origination calls, mobile destination calls, mobile location updates and inter-switch handovers. These functions will generate significant amount of data and require them to be transferred between databases (HLR, VLR) and switches (MSC's) very efficiently. In the future, the users (fixed or mobile) may use and communicate with sophisticated CPE's (e.g. multimedia, multipoint and multisession calls) which may require complex signaling functions. This will generate volumness service handling data and require efficient transfer of these message between databases and switches. Consequently, the network providers would be able to add new services and capabilities to their networks incrementally, quickly and cost-effectively.

  3. Waste management: how reducing partiality can promote efficient resource allocation.

    PubMed

    Choshen-Hillel, Shoham; Shaw, Alex; Caruso, Eugene M

    2015-08-01

    Two central principles that guide resource-allocation decisions are equity (providing equal pay for equal work) and efficiency (not wasting resources). When these two principles conflict with one another, people will often waste resources to avoid inequity. We suggest that people wish to avoid inequity not because they find it inherently unfair, but because they want to avoid the appearance of partiality associated with it. We explore one way to reduce waste by reducing the perceived partiality of inequitable allocations. Specifically, we hypothesize that people will be more likely to favor an efficient (albeit inequitable) allocation if it puts them in a disadvantaged position than if it puts others in a disadvantaged position. To test this hypothesis, we asked participants to choose between giving some extra resource to one person (thereby creating inequity between this person and equally deserving others) and not giving the resource to anyone (thereby wasting the resource). Six studies, using realistic scenarios and behavioral paradigms, provide robust evidence for a self-disadvantaging effect: Allocators were consistently more likely to create inequity to avoid wasting resources when the resulting inequity would put them at a relative disadvantage than when it would put others at a relative disadvantage. We further find that this self-disadvantaging effect is a direct result of people's concern about appearing partial. Our findings suggest the importance of impartiality even in distributive justice, thereby bridging a gap between the distributive and procedural justice literatures.

  4. Twin Signature Schemes, Revisited

    NASA Astrophysics Data System (ADS)

    Schäge, Sven

    In this paper, we revisit the twin signature scheme by Naccache, Pointcheval and Stern from CCS 2001 that is secure under the Strong RSA (SRSA) assumption and improve its efficiency in several ways. First, we present a new twin signature scheme that is based on the Strong Diffie-Hellman (SDH) assumption in bilinear groups and allows for very short signatures and key material. A big advantage of this scheme is that, in contrast to the original scheme, it does not require a computationally expensive function for mapping messages to primes. We prove this new scheme secure under adaptive chosen message attacks. Second, we present a modification that allows to significantly increase efficiency when signing long messages. This construction uses collision-resistant hash functions as its basis. As a result, our improvements make the signature length independent of the message size. Our construction deviates from the standard hash-and-sign approach in which the hash value of the message is signed in place of the message itself. We show that in the case of twin signatures, one can exploit the properties of the hash function as an integral part of the signature scheme. This improvement can be applied to both the SRSA based and SDH based twin signature scheme.

  5. Efficient Management of High-Throughput Screening Libraries with SAVANAH.

    PubMed

    List, Markus; Elnegaard, Marlene Pedersen; Schmidt, Steffen; Christiansen, Helle; Tan, Qihua; Mollenhauer, Jan; Baumbach, Jan

    2017-02-01

    High-throughput screening (HTS) has become an indispensable tool for the pharmaceutical industry and for biomedical research. A high degree of automation allows for experiments in the range of a few hundred up to several hundred thousand to be performed in close succession. The basis for such screens are molecular libraries, that is, microtiter plates with solubilized reagents such as siRNAs, shRNAs, miRNA inhibitors or mimics, and sgRNAs, or small compounds, that is, drugs. These reagents are typically condensed to provide enough material for covering several screens. Library plates thus need to be serially diluted before they can be used as assay plates. This process, however, leads to an explosion in the number of plates and samples to be tracked. Here, we present SAVANAH, the first tool to effectively manage molecular screening libraries across dilution series. It conveniently links (connects) sample information from the library to experimental results from the assay plates. All results can be exported to the R statistical environment or piped into HiTSeekR ( http://hitseekr.compbio.sdu.dk ) for comprehensive follow-up analyses. In summary, SAVANAH supports the HTS community in managing and analyzing HTS experiments with an emphasis on serially diluted molecular libraries.

  6. Nanoinformatics knowledge infrastructures: bringing efficient information management to nanomedical research

    NASA Astrophysics Data System (ADS)

    de la Iglesia, D.; Cachau, R. E.; García-Remesal, M.; Maojo, V.

    2013-01-01

    Nanotechnology represents an area of particular promise and significant opportunity across multiple scientific disciplines. Ongoing nanotechnology research ranges from the characterization of nanoparticles and nanomaterials to the analysis and processing of experimental data seeking correlations between nanoparticles and their functionalities and side effects. Due to their special properties, nanoparticles are suitable for cellular-level diagnostics and therapy, offering numerous applications in medicine, e.g. development of biomedical devices, tissue repair, drug delivery systems and biosensors. In nanomedicine, recent studies are producing large amounts of structural and property data, highlighting the role for computational approaches in information management. While in vitro and in vivo assays are expensive, the cost of computing is falling. Furthermore, improvements in the accuracy of computational methods (e.g. data mining, knowledge discovery, modeling and simulation) have enabled effective tools to automate the extraction, management and storage of these vast data volumes. Since this information is widely distributed, one major issue is how to locate and access data where it resides (which also poses data-sharing limitations). The novel discipline of nanoinformatics addresses the information challenges related to nanotechnology research. In this paper, we summarize the needs and challenges in the field and present an overview of extant initiatives and efforts.

  7. Nanoinformatics knowledge infrastructures: bringing efficient information management to nanomedical research.

    PubMed

    de la Iglesia, D; Cachau, R E; García-Remesal, M; Maojo, V

    2013-11-27

    Nanotechnology represents an area of particular promise and significant opportunity across multiple scientific disciplines. Ongoing nanotechnology research ranges from the characterization of nanoparticles and nanomaterials to the analysis and processing of experimental data seeking correlations between nanoparticles and their functionalities and side effects. Due to their special properties, nanoparticles are suitable for cellular-level diagnostics and therapy, offering numerous applications in medicine, e.g. development of biomedical devices, tissue repair, drug delivery systems and biosensors. In nanomedicine, recent studies are producing large amounts of structural and property data, highlighting the role for computational approaches in information management. While in vitro and in vivo assays are expensive, the cost of computing is falling. Furthermore, improvements in the accuracy of computational methods (e.g. data mining, knowledge discovery, modeling and simulation) have enabled effective tools to automate the extraction, management and storage of these vast data volumes. Since this information is widely distributed, one major issue is how to locate and access data where it resides (which also poses data-sharing limitations). The novel discipline of nanoinformatics addresses the information challenges related to nanotechnology research. In this paper, we summarize the needs and challenges in the field and present an overview of extant initiatives and efforts.

  8. Nanoinformatics knowledge infrastructures: bringing efficient information management to nanomedical research

    PubMed Central

    de la Iglesia, D; Cachau, R E; García-Remesal, M; Maojo, V

    2014-01-01

    Nanotechnology represents an area of particular promise and significant opportunity across multiple scientific disciplines. Ongoing nanotechnology research ranges from the characterization of nanoparticles and nanomaterials to the analysis and processing of experimental data seeking correlations between nanoparticles and their functionalities and side effects. Due to their special properties, nanoparticles are suitable for cellular-level diagnostics and therapy, offering numerous applications in medicine, e.g. development of biomedical devices, tissue repair, drug delivery systems and biosensors. In nanomedicine, recent studies are producing large amounts of structural and property data, highlighting the role for computational approaches in information management. While in vitro and in vivo assays are expensive, the cost of computing is falling. Furthermore, improvements in the accuracy of computational methods (e.g. data mining, knowledge discovery, modeling and simulation) have enabled effective tools to automate the extraction, management and storage of these vast data volumes. Since this information is widely distributed, one major issue is how to locate and access data where it resides (which also poses data-sharing limitations). The novel discipline of nanoinformatics addresses the information challenges related to nanotechnology research. In this paper, we summarize the needs and challenges in the field and present an overview of extant initiatives and efforts. PMID:24932210

  9. A case study for efficient management of high throughput primary lab data

    PubMed Central

    2011-01-01

    Background In modern life science research it is very important to have an efficient management of high throughput primary lab data. To realise such an efficient management, four main aspects have to be handled: (I) long term storage, (II) security, (III) upload and (IV) retrieval. Findings In this paper we define central requirements for a primary lab data management and discuss aspects of best practices to realise these requirements. As a proof of concept, we introduce a pipeline that has been implemented in order to manage primary lab data at the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK). It comprises: (I) a data storage implementation including a Hierarchical Storage Management system, a relational Oracle Database Management System and a BFiler package to store primary lab data and their meta information, (II) the Virtual Private Database (VPD) implementation for the realisation of data security and the LIMS Light application to (III) upload and (IV) retrieve stored primary lab data. Conclusions With the LIMS Light system we have developed a primary data management system which provides an efficient storage system with a Hierarchical Storage Management System and an Oracle relational database. With our VPD Access Control Method we can guarantee the security of the stored primary data. Furthermore the system provides high performance upload and download and efficient retrieval of data. PMID:22005096

  10. [Emergency care of vertigo patients: suggestions for efficient management].

    PubMed

    Kogashiwa, Yasunao; Takei, Yasuhiko; Matsuda, Takeaki; Karaho, Takehiro; Morita, Masahiro; Kohno, Naoyuki

    2009-10-01

    Some diseases in which persons show vertigo or dizziness may be life-threatening, regardless of symptom severity, and require careful attention. These include diseases of the inner ear, central nervous system, and cardiovascular manifestation. In May 2006, a group in charge of primary emergency consultation began work enabling physicians to treat vertigo patients more efficiently and safely, as detailed in this report. Of the 173 persons with vertigo hospitalized from January 2004 to March 2008, six had cerebrovascular manifestations clarified only after hospitalization, underscoring the importance of careful examination, especially of those 75 years of age older, having continuous headache, having severe trunk ataxia despite apparently mild eye nystagmus, or reporting a history of high blood pressure, diabetes mellitus, hyperlipidemia, or ischemic heart disease.

  11. Towards Efficient Scientific Data Management Using Cloud Storage

    NASA Technical Reports Server (NTRS)

    He, Qiming

    2013-01-01

    A software prototype allows users to backup and restore data to/from both public and private cloud storage such as Amazon's S3 and NASA's Nebula. Unlike other off-the-shelf tools, this software ensures user data security in the cloud (through encryption), and minimizes users operating costs by using space- and bandwidth-efficient compression and incremental backup. Parallel data processing utilities have also been developed by using massively scalable cloud computing in conjunction with cloud storage. One of the innovations in this software is using modified open source components to work with a private cloud like NASA Nebula. Another innovation is porting the complex backup to- cloud software to embedded Linux, running on the home networking devices, in order to benefit more users.

  12. Compound Hub: efficiency gains through innovative sample management processes.

    PubMed

    Schopfer, Ulrich; Andreae, Marc R M; Hueber, Matthieu; Saur, Andreas; Kummer, Marcel O; Girod, Michel; Fox, Desmond; Steiner, Thomas; Popov, Maxim; Smith, Robert

    2007-05-01

    While significant investments are made across the industry and increasingly also in academia to enhance or build a compound file, the efficient sourcing of compounds from in-house medical chemistry is frequently seen as a challenge. This article introduces the Compound Hub strategy developed at the Novartis Compound Archive. Central Compound Hubs in Basel and Cambridge were combined with web-based ordering of compounds and assays, providing assay-ready, solubilized samples to labs anywhere in the global research organization. Relieving scientists from time-intensive sample preparation tasks, error rates could be reduced through electronic processing and tracking of compounds/assays and the capture of medicinal chemistry compounds for the compound library could be increased by 75%.

  13. Developing a risk-based trading scheme for cattle in England: farmer perspectives on managing trading risk for bovine tuberculosis.

    PubMed

    Little, R; Wheeler, K; Edge, S

    2017-02-11

    This paper examines farmer attitudes towards the development of a voluntary risk-based trading scheme for cattle in England as a risk mitigation measure for bovine tuberculosis (bTB). The research reported here was commissioned to gather evidence on the type of scheme that would have a good chance of success in improving the information farmers receive about the bTB risk of cattle they buy. Telephone interviews were conducted with a stratified random sample of 203 cattle farmers in England, splitting the interviews equally between respondents in the high-risk area and low-risk area for bTB. Supplementary interviews and focus groups with farmers were also carried out across the risk areas. Results suggest a greater enthusiasm for a risk-based trading scheme in low-risk areas compared with high-risk areas and among members of breed societies and cattle health schemes. Third-party certification of herds by private vets or the Animal and Plant Health Agency were regarded as the most credible source, with farmer self-certification being favoured by sellers, but being regarded as least credible by buyers. Understanding farmers' attitudes towards voluntary risk-based trading is important to gauge likely uptake, understand preferences for information provision and to assist in monitoring, evaluating and refining the scheme once established.

  14. Enhanced efficiency in high-brightness fluorescent organic light emitting diodes through triplet management

    NASA Astrophysics Data System (ADS)

    Zhang, Yifan; Slootsky, Michael; Forrest, Stephen R.

    2011-11-01

    We demonstrate suppressed singlet-triplet (S-T) quenching, and hence increased quantum efficiency, in high-brightness fluorescent organic light emitting diodes (OLEDs) by reducing the guest triplet population through the introduction of a triplet manager molecule into the emission layer (EML). As an example, an OLED whose EML consists of the red fluorophore, 4-(dicyanomethylene)-2-methyl-6-julolidyl-9-enyl-4H-pyran doped into the host, tris(8-hydroxyquinoline) Al (Alq3) is blended with the triplet manager, 9,10-di(naphtha-2-yl)anthracene. The manager triplet energy is less than that of the host or dopant, leading to efficient triplet removal from the dopant without affecting the radiative singlet population. Measurements suggest the complete suppression of S-T quenching using the triplet management strategy, leading to >100% increase in the steady-state OLED external quantum efficiency.

  15. A measurement of the effectiveness and efficiency of pre-disaster debris management plans.

    PubMed

    Crowley, Julia

    2017-04-01

    Disaster debris management operations make up a significant portion of recovery expenses. The following study aims to examine how the presence of a plan makes disaster debris management effective and efficient. Ninety-five counties in the United States who received major disaster declarations between 2012 and 2015 were surveyed to examine the quality of their debris management processes. Forty-nine of these counties had debris management plans while forty-six did not. Statistical tests were conducted to address discrepancies in the effectiveness and efficiency of the debris management processes between the two groups. Such tests suggest that counties with pre-disaster debris management plans were more effective. These counties recycled almost twice as much disaster debris as counties without plans, and received over three times as much Public Assistance from the Federal Emergency Management Agency (FEMA). Counties with plans also reported higher levels of perceived preparedness for future debris challenges than counties without plans. Overall, counties with pre-disaster debris management plans were partially more efficient than counties without plans. They removed more cubic yards of debris per day, but there were no statistically significant differences between the two groups in the volume of debris removed per dollar. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Impact of changed management policies on operating room efficiency.

    PubMed

    Sandbaek, Birgithe E; Helgheim, Berit I; Larsen, Odd I; Fasting, Sigurd

    2014-05-20

    To increase operating room (OR) efficiency, a new resource allocation strategy, a new policy for patient urgency classification, and a new system for OR booking was implemented at a tertiary referral hospital. We investigated the impact of these interventions. We carried out a before-and-after study using OR data. A total of 23,515 elective (planned) and non-elective (unplanned) orthopaedic and general surgeries were conducted during calendar year 2007 (period 1) and July 2008 to July 2009 (period 2). The Wilcoxon-Mann-Whitney test was used to calculate statistical significance. An increased amount of case time (7.1%, p < 0.05) was conducted without any increase in out-of-hours case time. Despite having three fewer ORs for electives, slightly more elective case time was handled with 26% less use of overtime (p < 0.05). Mean OR utilization was 56% for the 17 mixed ORs, 60% for the 14 elective ORs, and 62% for the 3 dedicated ORs. A 20% growth (p < 0.05) of non-elective case