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Sample records for allocation scheme based

  1. Adaptive QoS Class Allocation Schemes in Multi-Domain Path-Based Networks

    NASA Astrophysics Data System (ADS)

    Ogino, Nagao; Nakamura, Hajime

    MPLS-based path technology shows promise as a means of realizing reliable IP networks. Real-time services such as VoIP and video-conference supplied through a multi-domain MPLS network must be able to guarantee end-to-end QoS of the inter-domain paths. Thus, it is important to allocate an appropriate QoS class to the inter-domain paths in each domain traversed by the inter-domain paths. Because each domain has its own policy for QoS class allocation, it is necessary to adaptively allocate the optimum QoS class based on estimation of the QoS class allocation policies in other domains. This paper proposes two kinds of adaptive QoS class allocation schemes, assuming that the arriving inter-domain path requests include the number of downstream domains traversed by the inter-domain paths and the remaining QoS value toward the destination nodes. First, a measurement-based scheme, based on measurement of the loss rates of inter-domain paths in the downstream domains, is proposed. This scheme estimates the QoS class allocation policies in the downstream domains, using the measured loss rates of path requests. Second, a state-dependent type scheme, based on measurement of the arrival rates of path requests in addition to the loss rates of paths in the downstream domains, is also proposed. This scheme allows an appropriate QoS class to be allocated according to the domain state. This paper proposes an application of the Markov decision theory to the modeling of state-dependent type scheme. The performances of the proposed schemes are evaluated and compared with those of the other less complicated non-adaptive schemes using a computer simulation. The results of the comparison reveal that the proposed schemes can adaptively increase the number of inter-domain paths accommodated in the considered domain, even when the QoS class allocation policies change in the other domains and the arrival pattern of path requests varies in the considered domain.

  2. A dynamic bandwidth allocation scheme for EPON

    NASA Astrophysics Data System (ADS)

    Li, Xiuyuan; Wu, Xiaojuan; Ma, Maode; Li, Wenming; Zhang, Yuanyuan

    2008-11-01

    This paper analyses current bandwidth schemes and proposes a novel dynamic bandwidth allocation scheme for EPON. According the scheme, we define four kinds of multimedia services such as Unsolicited Request Service (URS), Realtime Service (rt-S), Non-Real-time Service (nrt-S) and Best Effort (BE). Different kinds of services have different Quality of Service (QoS) requirements. Our scheme considers the diverse QoS request, e.g., delay for rt-S, throughput for nrt-S and fairness for BE. The simulation results show this novel scheme can ensure the quality of service (QoS) and improve bandwidth utilization.

  3. Network coding based joint signaling and dynamic bandwidth allocation scheme for inter optical network unit communication in passive optical networks

    NASA Astrophysics Data System (ADS)

    Wei, Pei; Gu, Rentao; Ji, Yuefeng

    2014-06-01

    As an innovative and promising technology, network coding has been introduced to passive optical networks (PON) in recent years to support inter optical network unit (ONU) communication, yet the signaling process and dynamic bandwidth allocation (DBA) in PON with network coding (NC-PON) still need further study. Thus, we propose a joint signaling and DBA scheme for efficiently supporting differentiated services of inter ONU communication in NC-PON. In the proposed joint scheme, the signaling process lays the foundation to fulfill network coding in PON, and it can not only avoid the potential threat to downstream security in previous schemes but also be suitable for the proposed hybrid dynamic bandwidth allocation (HDBA) scheme. In HDBA, a DBA cycle is divided into two sub-cycles for applying different coding, scheduling and bandwidth allocation strategies to differentiated classes of services. Besides, as network traffic load varies, the entire upstream transmission window for all REPORT messages slides accordingly, leaving the transmission time of one or two sub-cycles to overlap with the bandwidth allocation calculation time at the optical line terminal (the OLT), so that the upstream idle time can be efficiently eliminated. Performance evaluation results validate that compared with the existing two DBA algorithms deployed in NC-PON, HDBA demonstrates the best quality of service (QoS) support in terms of delay for all classes of services, especially guarantees the end-to-end delay bound of high class services. Specifically, HDBA can eliminate queuing delay and scheduling delay of high class services, reduce those of lower class services by at least 20%, and reduce the average end-to-end delay of all services over 50%. Moreover, HDBA also achieves the maximum delay fairness between coded and uncoded lower class services, and medium delay fairness for high class services.

  4. Interference Avoiding Radio Resource Allocation Scheme for Multi-hop OFDMA Cellular Networks with Random Topology

    NASA Astrophysics Data System (ADS)

    Lim, Sunggook; Lee, Jaiyong

    Relaying technology is the one of the solutions to expand the coverage and enhance the throughput of a cellular network with low cost, therefore numerous smart relay stations (RSs) which are able to schedule its own transmission frame and manage radio resources allocated by its serving base station (BS) will be deployed within the cellular network. while more RSs are deployed, the network topology is turning to the random topology. In the random topology, however, conventional frequency reuse schemes based on the uniformly distributed RSs are not adoptable because of the randomness for locations of RSs. Another problem is severe increase of interference during the transmission period for an access link because more transmitters including BSs and RSs are existed within a cell. We suggest the random-topology frequency reuse (RFR) scheme supporting the frequency reuse in the cellular multi-hop network with random topology to reduce intra-cell interference. The simulation results show RFR is reducing the overall intra-cell interference compared to the full allocation scheme whose reuse factor is one. The throughput and average signal to interference plus noise ratio (SINR) is still greater than the full allocation scheme although the spectral efficiency is lower than the compared scheme.

  5. Continuity Aware Spectrum Allocation Schemes for Virtual Optical Network Embedding in Elastic Optical Networks

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Zhao, Yongli; He, Ruiying; Yu, Xiaosong; Zhang, Jie; Zheng, Haomian; Lin, Yi; Han, Jianrui

    2016-05-01

    Optical network virtualization has been studied as a promising technique for optical network resources provisioning. In the virtualization context of Elastic Optical Network (EON), Virtual Optical Network Embedding (VONE) is investigated as a key issue for allocating spectrum resources to VON requests. This paper discusses the continuity constraint for the VONE problem in EONs, and presents three continuity-aware spectrum allocation schemes according to strict and relaxed continuity constraints. We have demonstrated the proposed schemes on emulated testbed to verify the feasibility of composing VON with discontiguous spectrum resources. Additionally, the performances of the proposed schemes are compared via simulation in terms of blocking probability, spectrum resource utilization and discontinuity degree.

  6. Fairness issues in resource allocation schemes for wireless visual sensor networks

    NASA Astrophysics Data System (ADS)

    Pandremmenou, Katerina; Kondi, Lisimachos P.; Parsopoulos, Konstantinos E.

    2013-02-01

    This work addresses the problem of fairness and efficiency evaluation of various resource allocation schemes for wireless visual sensor networks (VSNs). These schemes are used to optimally allocate the source coding rates, channel coding rates, and power levels among the nodes of a wireless direct sequence code division multiple access (DS-CDMA) VSN. All of the considered schemes optimize a function of the video qualities of the nodes. However, there is no single scheme that maximizes the video quality of each node simultaneously. In fact, all presented schemes are able to provide a Pareto-optimal solution, meaning that there is no other solution that is simultaneously preferred by all nodes. Thus, it is not clear which scheme results in the best resource allocation for the whole network. To handle the resulting tradeoffs, in this study we examine four metrics that investigate fairness and efficiency under different perspectives. Specifically, we apply a metric that considers both fairness and performance issues, and another metric that measures the "equality" of a resource allocation (equal utilities for the nodes). The third metric computes the total system utility, while the last metric computes the total power consumption of the nodes. Ideally, a desirable scheme would achieve high total utility while being equally fair to all nodes and requiring low amounts of power.

  7. An Efficient Resource Allocation Scheme for VoIP Services in the IEEE 802.16e OFDMA System

    NASA Astrophysics Data System (ADS)

    So, Jae-Woo

    In this letter, we propose an efficient resource allocation scheme that improves the system performance by reducing the signaling overhead for voice over Internet protocol (VoIP) services in the IEEE 802.16e OFDMA system. We theoretically analyze the performance of the proposed allocation scheme and carry out a computer simulation to evaluate the FA scheme.

  8. Dynamic resource allocation scheme for distributed heterogeneous computer systems

    NASA Technical Reports Server (NTRS)

    Liu, Howard T. (Inventor); Silvester, John A. (Inventor)

    1991-01-01

    This invention relates to a resource allocation in computer systems, and more particularly, to a method and associated apparatus for shortening response time and improving efficiency of a heterogeneous distributed networked computer system by reallocating the jobs queued up for busy nodes to idle, or less-busy nodes. In accordance with the algorithm (SIDA for short), the load-sharing is initiated by the server device in a manner such that extra overhead in not imposed on the system during heavily-loaded conditions. The algorithm employed in the present invention uses a dual-mode, server-initiated approach. Jobs are transferred from heavily burdened nodes (i.e., over a high threshold limit) to low burdened nodes at the initiation of the receiving node when: (1) a job finishes at a node which is burdened below a pre-established threshold level, or (2) a node is idle for a period of time as established by a wakeup timer at the node. The invention uses a combination of the local queue length and the local service rate ratio at each node as the workload indicator.

  9. Classroom Games: The Allocation of Renewable Resources under Different Property Rights and Regulation Schemes.

    ERIC Educational Resources Information Center

    Giraud, Kelly L.; Herrmann, Mark

    2002-01-01

    Describes a renewable resource allocation game designed to stimulate student interest in and understanding of market failure associated with open-access types of resource use. Employs the game to discuss advantages and disadvantages of property rights and regulation schemes. States the game benefits noneconomics majors in natural resource…

  10. Dynamic and balanced capacity allocation scheme with uniform bandwidth for OFDM-PON systems

    NASA Astrophysics Data System (ADS)

    Lei, Cheng; Chen, Hongwei; Chen, Minghua; Yu, Ying; Guo, Qiang; Yang, Sigang; Xie, Shizhong

    2015-03-01

    As the bitrate of orthogonal frequency division multiplexing passive optical network (OFDM-PON) system is continuously increasing, how to effectively allocate the system bandwidth among the huge number of optical network units (ONUs) is one of the key problems before OFDM-PON can be practical deployed. Unlike traditional bandwidth allocation scheme, in this paper, the transmission performance of single ONU is for the first time taken into consideration and optimized. To reduce the manufacturing complexity and fully utilize the processing ability of the receivers, the system bandwidth is equally distributed to the ONUs. Bit loading is used to allocate the total transmission capacity, and power loading is used to guarantee the ONUs have balanced transmission performance even if they operate at different bitrate. In this way, a dynamic and balanced capacity allocation scheme with uniform bandwidth for OFDM-PON systems can be realized. At last, an experimental system is established to verify the feasibility of the proposed scheme, and the influence that the scheme brings to the whole system is also analyzed.

  11. Resource Allocation and Power Management Schemes in an LTE-Advanced Femtocell Network

    NASA Astrophysics Data System (ADS)

    Lee, Byung-Bog; Yu, Jae-Hak; Lee, In-Hwan; Pyo, Cheol-Sig; Kim, Se-Jin

    In this letter, we introduce two different resource allocation and Tx power management schemes, called resource control and fixed power (RCFP) and fixed resource and power control (FRPC), in an LTE-Advanced femtocell network. We analyze and compare the two schemes in terms of the system throughput for downlink and energy consumption of home evolved NodeB (HeNB) Tx power according to the number of HeNBs and home user equipment (HUE)'s user traffic density (C). The simulation results show that the FRPC scheme has better performance in terms of system throughput for macro user equipments (MUEs) and energy consumption in low C.

  12. A novel scheme for graft allocation in non-heart beating donor renal transplantation.

    PubMed

    Laugharne, Matthew J; Clarke, Elaine; Younie, Mary E; Johnson, Rachel J; Rudge, Christopher J; Pentlow, Barry D; Morgan, Justin D; Dudley, Christopher R

    2008-06-15

    Patients waiting more than 3 years for a renal transplant were ranked according to our novel Bristol and Region Allocation by Non-heart beating Donor Score (BRANDS). One kidney from 40 non-heart beating donors was allocated to the highest BRANDS long-waiter and the other kidney allocated according to the UK National Allocation Scheme (NAS). The scheme reduced the number of patients waiting more than 3 years by 20%. Despite longer dialysis time, greater sensitization and more human leukocyte antigen mismatches, BRANDS patients had equivalent 3-year graft survival (BRANDS 91%, NAS 97%, P=0.264) and patient survival (BRANDS 94%, NAS 92%, P=0.99). Results were similar to 242 synchronous recipients from heart-beating donors. Renal function was significantly lower in BRANDS recipients (40 vs. 62 mL/min/1.73 m2, P<0.0001). Transplanting long-waiting patients with kidneys from non-heart beating donors has reduced waiting times without compromising early outcomes. It is unclear if equivalent survival will be sustained in the long term. PMID:18551076

  13. A nonlinearity interval mapping scheme for efficient waste load allocation simulation-optimization analysis

    NASA Astrophysics Data System (ADS)

    Zou, Rui; Liu, Yong; Riverson, John; Parker, Andrew; Carter, Stephen

    2010-08-01

    Applications using simulation-optimization approaches are often limited in practice because of the high computational cost associated with executing the simulation-optimization analysis. This research proposes a nonlinearity interval mapping scheme (NIMS) to overcome the computational barrier of applying the simulation-optimization approach for a waste load allocation analysis. Unlike the traditional response surface methods that use response surface functions to approximate the functional form of the original simulation model, the NIMS approach involves mapping the nonlinear input-output response relationship of a simulation model into an interval matrix, thereby converting the original simulation-optimization model into an interval linear programming model. By using the risk explicit interval linear programming algorithm and an inverse mapping scheme to implicitly resolve nonlinearity in the interval linear programming model, the NIMS approach efficiently obtained near-optimal solutions of the original simulation-optimization problem. The NIMS approach was applied to a case study on Wissahickon Creek in Pennsylvania, with the objective of finding optimal carbonaceous biological oxygen demand and ammonia (NH4) point source waste load allocations, subject to daily average and minimum dissolved oxygen compliance constraints at multiple points along the stream. First, a simulation-optimization model was formulated for this case study. Next, a genetic algorithm was used to solve the problem to produce reference optimal solutions. Finally, the simulation-optimization model was solved using the proposed NIMS, and the obtained solutions were compared with the reference solutions to demonstrate the superior computational efficiency and solution quality of the NIMS.

  14. Routing and spectrum allocation in multi-ring based data center networks

    NASA Astrophysics Data System (ADS)

    Zhang, Zitian; Hu, Weisheng; Ye, Tong; Sun, Weiqiang; Zhao, Li; Zhang, Kuo

    2016-02-01

    Recently, we proposed a multi-ring based optical circuit switching (OCS) network following the principle of a Clos network. The network can provide connectivity to a large number of racks which may be distributed across a relatively large geographical space in a data center. However, property of the ring based switch in the central stage of the multi-ring based OCS network introduces a unique routing and spectrum allocation (RSA) problem which is more complex than the routing problem in a classical Clos switching network. In this paper, we extend our work to investigate the RSA problem. For a given set of inter-rack traffic requests, we consider two spectrum allocation schemes, namely fixed spectrum allocation and flexible spectrum allocation. For the fixed case, we show that the RSA problem degenerates into the traditional routing problem of the Clos network. As for the flexible case, property of spectrum division multiplexing technology and bandwidth limitation of the ring based switches should be taken into consideration during allocation of the central module, such that the system throughput can be maximized. This paper presents an integer linear program (ILP) formulation as well as a heuristic algorithm we developed to solve the flexible RSA problem. We evaluate the performance of both the two spectrum allocation schemes under different traffic patterns. Our results demonstrate that, to handle uneven inter-rack traffic pattern in general data center networks, flexible spectrum allocation can lead to an increase of about 120% in system throughput, although its computational complexity is slightly higher than that of the fixed spectrum allocation scheme.

  15. 47 CFR 69.502 - Base factor allocation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Base factor allocation. 69.502 Section 69.502... Segregation of Common Line Element Revenue Requirement § 69.502 Base factor allocation. Projected revenues from the following shall be deducted from the base factor portion to determine the amount that...

  16. 47 CFR 69.502 - Base factor allocation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Base factor allocation. 69.502 Section 69.502 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) ACCESS CHARGES Segregation of Common Line Element Revenue Requirement § 69.502 Base factor allocation. Projected...

  17. Efficiency of Fiscal Allocations in Site-Based Empowered Schools

    ERIC Educational Resources Information Center

    Meyer, Jerome Jay

    2011-01-01

    This study implemented a two phase concurrent mixed-methods design to generate a greater understanding of how elementary schools with increased autonomy in fiscal decision making allocated their money, how their site-based decisions affected allocative efficiency, and how increased autonomy affected site-based decision making when compared with a…

  18. Stereoscopic Visual Attention-Based Regional Bit Allocation Optimization for Multiview Video Coding

    NASA Astrophysics Data System (ADS)

    Zhang, Yun; Jiang, Gangyi; Yu, Mei; Chen, Ken; Dai, Qionghai

    2010-12-01

    We propose a Stereoscopic Visual Attention- (SVA-) based regional bit allocation optimization for Multiview Video Coding (MVC) by the exploiting visual redundancies from human perceptions. We propose a novel SVA model, where multiple perceptual stimuli including depth, motion, intensity, color, and orientation contrast are utilized, to simulate the visual attention mechanisms of human visual system with stereoscopic perception. Then, a semantic region-of-interest (ROI) is extracted based on the saliency maps of SVA. Both objective and subjective evaluations of extracted ROIs indicated that the proposed SVA model based on ROI extraction scheme outperforms the schemes only using spatial or/and temporal visual attention clues. Finally, by using the extracted SVA-based ROIs, a regional bit allocation optimization scheme is presented to allocate more bits on SVA-based ROIs for high image quality and fewer bits on background regions for efficient compression purpose. Experimental results on MVC show that the proposed regional bit allocation algorithm can achieve over [InlineEquation not available: see fulltext.]% bit-rate saving while maintaining the subjective image quality. Meanwhile, the image quality of ROIs is improved by [InlineEquation not available: see fulltext.] dB at the cost of insensitive image quality degradation of the background image.

  19. Scientific program construction principles and time allocation scheme for the World Space Observatory—Ultraviolet mission

    NASA Astrophysics Data System (ADS)

    Malkov, Oleg; Sachkov, Mikhail; Shustov, Boris; Kaigorodov, Pavel; Yáñez, Francisco Javier; Gómez de Castro, Ana Ines

    2011-09-01

    We present scientific program construction principles and a time allocation scheme developed for the World Space Observatory—Ultraviolet (WSO-UV) mission, which is an international space observatory for observation in UV spectral range 100-300 nm. The WSO-UV consists of a 1.7 m aperture telescope with instrumentation designed to carry out high resolution spectroscopy, long-slit low resolution spectroscopy and direct sky imaging. The WSO-UV Ground Segment is under development by Spain and Russia. They will coordinate the Mission and Science Operations and provide the satellite tracking stations for the project. The WSO-UV will work as a targeted scientific observatory. Three scientific programs will be carried out at the observatory. Core Program of scientific observations, which deserves large amounts of observing time, will be defined by the WSO-UV Science Committee to allow the conduction of high impact or legacy scientific projects. Funding Bodies Program is the guaranteed time granted to each one of the national bodies funding the WSO-UV project. Guest observer program for everyone, or Open Program, consists of astronomical observations obtained with the WSO-UV by astronomers who may or may not belong to the WSO-UV international consortium. It is open to excellent scientific projects from the world-wide community and occupies up to 40% of total observational time. Apart from the particularities associated to a science mission, this new mission will be affected by a new concept of observations management, trying to maximize the scientific return of this mission, and the shared operations between the two sites located in Spain and Russia. A brief summary of the algorithmic strategies analyzed for scheduling optimization is also given in the paper.

  20. Quantum Authentication Scheme Based on Entanglement Swapping

    NASA Astrophysics Data System (ADS)

    Penghao, Niu; Yuan, Chen; Chong, Li

    2016-01-01

    Based on the entanglement swapping, a quantum authentication scheme with a trusted- party is proposed in this paper. With this scheme, two users can perform mutual identity authentication to confirm each other's validity. In addition, the scheme is proved to be secure under circumstances where a malicious attacker is capable of monitoring the classical and quantum channels and has the power to forge all information on the public channel.

  1. Study of network resource allocation based on market and game theoretic mechanism

    NASA Astrophysics Data System (ADS)

    Liu, Yingmei; Wang, Hongwei; Wang, Gang

    2004-04-01

    We work on the network resource allocation issue concerning network management system function based on market-oriented mechanism. The scheme is to model the telecommunication network resources as trading goods in which the various network components could be owned by different competitive, real-world entities. This is a multidisciplinary framework concentrating on the similarity between resource allocation in network environment and the market mechanism in economic theory. By taking an economic (market-based and game theoretic) approach in routing of communication network, we study the dynamic behavior under game-theoretic framework in allocating network resources. Based on the prior work of Gibney and Jennings, we apply concepts of utility and fitness to the market mechanism with an intention to close the gap between experiment environment and real world situation.

  2. Staged optimization algorithms based MAC dynamic bandwidth allocation for OFDMA-PON

    NASA Astrophysics Data System (ADS)

    Liu, Yafan; Qian, Chen; Cao, Bingyao; Dun, Han; Shi, Yan; Zou, Junni; Lin, Rujian; Wang, Min

    2016-06-01

    Orthogonal frequency division multiple access passive optical network (OFDMA-PON) has being considered as a promising solution for next generation PONs due to its high spectral efficiency and flexible bandwidth allocation scheme. In order to take full advantage of these merits of OFDMA-PON, a high-efficiency medium access control (MAC) dynamic bandwidth allocation (DBA) scheme is needed. In this paper, we propose two DBA algorithms which can act on two different stages of a resource allocation process. To achieve higher bandwidth utilization and ensure the equity of ONUs, we propose a DBA algorithm based on frame structure for the stage of physical layer mapping. Targeting the global quality of service (QoS) of OFDMA-PON, we propose a full-range DBA algorithm with service level agreement (SLA) and class of service (CoS) for the stage of bandwidth allocation arbitration. The performance of the proposed MAC DBA scheme containing these two algorithms is evaluated using numerical simulations. Simulations of a 15 Gbps network with 1024 sub-carriers and 32 ONUs demonstrate the maximum network throughput of 14.87 Gbps and the maximum packet delay of 1.45 ms for the highest priority CoS under high load condition.

  3. Multi-robot task allocation based on two dimensional artificial fish swarm algorithm

    NASA Astrophysics Data System (ADS)

    Zheng, Taixiong; Li, Xueqin; Yang, Liangyi

    2007-12-01

    The problem of task allocation for multiple robots is to allocate more relative-tasks to less relative-robots so as to minimize the processing time of these tasks. In order to get optimal multi-robot task allocation scheme, a twodimensional artificial swarm algorithm based approach is proposed in this paper. In this approach, the normal artificial fish is extended to be two dimension artificial fish. In the two dimension artificial fish, each vector of primary artificial fish is extended to be an m-dimensional vector. Thus, each vector can express a group of tasks. By redefining the distance between artificial fish and the center of artificial fish, the behavior of two dimension fish is designed and the task allocation algorithm based on two dimension artificial swarm algorithm is put forward. At last, the proposed algorithm is applied to the problem of multi-robot task allocation and comparer with GA and SA based algorithm is done. Simulation and compare result shows the proposed algorithm is effective.

  4. Palmprint based multidimensional fuzzy vault scheme.

    PubMed

    Liu, Hailun; Sun, Dongmei; Xiong, Ke; Qiu, Zhengding

    2014-01-01

    Fuzzy vault scheme (FVS) is one of the most popular biometric cryptosystems for biometric template protection. However, error correcting code (ECC) proposed in FVS is not appropriate to deal with real-valued biometric intraclass variances. In this paper, we propose a multidimensional fuzzy vault scheme (MDFVS) in which a general subspace error-tolerant mechanism is designed and embedded into FVS to handle intraclass variances. Palmprint is one of the most important biometrics; to protect palmprint templates; a palmprint based MDFVS implementation is also presented. Experimental results show that the proposed scheme not only can deal with intraclass variances effectively but also could maintain the accuracy and meanwhile enhance security. PMID:24892094

  5. Palmprint Based Multidimensional Fuzzy Vault Scheme

    PubMed Central

    Liu, Hailun; Sun, Dongmei; Xiong, Ke; Qiu, Zhengding

    2014-01-01

    Fuzzy vault scheme (FVS) is one of the most popular biometric cryptosystems for biometric template protection. However, error correcting code (ECC) proposed in FVS is not appropriate to deal with real-valued biometric intraclass variances. In this paper, we propose a multidimensional fuzzy vault scheme (MDFVS) in which a general subspace error-tolerant mechanism is designed and embedded into FVS to handle intraclass variances. Palmprint is one of the most important biometrics; to protect palmprint templates; a palmprint based MDFVS implementation is also presented. Experimental results show that the proposed scheme not only can deal with intraclass variances effectively but also could maintain the accuracy and meanwhile enhance security. PMID:24892094

  6. Signature scheme based on bilinear pairs

    NASA Astrophysics Data System (ADS)

    Tong, Rui Y.; Geng, Yong J.

    2013-03-01

    An identity-based signature scheme is proposed by using bilinear pairs technology. The scheme uses user's identity information as public key such as email address, IP address, telephone number so that it erases the cost of forming and managing public key infrastructure and avoids the problem of user private generating center generating forgery signature by using CL-PKC framework to generate user's private key.

  7. Ethical considerations surrounding survival benefit-based liver allocation.

    PubMed

    Keller, Eric J; Kwo, Paul Y; Helft, Paul R

    2014-02-01

    The disparity between the demand for and supply of donor livers has continued to grow over the last 2 decades, and this has placed greater weight on the need for efficient and effective liver allocation. Although the use of extended criteria donors has shown great potential, it remains unregulated. A survival benefit-based model was recently proposed to answer calls to increase efficiency and reduce futile transplants. However, it was previously determined that the current allocation system was not in need of modification and that instead geographic disparities should be addressed. In contrast, we believe that there is a significant need to replace the current allocation system and complement efforts to improve donor liver distribution. We illustrate this need first by identifying major ethical concerns shaping liver allocation and then by using these concerns to identify strengths and shortcomings of the Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease system and a survival benefit-based model. The latter model is a promising means of improving liver allocation: it incorporates a greater number of ethical principles, uses a sophisticated statistical model to increase efficiency and reduce waste, minimizes bias, and parallels developments in the allocation of other organs. However, it remains limited in its posttransplant predictive accuracy and may raise potential issues regarding informed consent. In addition, the proposed model fails to include quality-of-life concerns and prioritize younger patients. We feel that it is time to take the next steps toward better liver allocation not only through reductions in geographic disparities but also through the adoption of a model better equipped to balance the many ethical concerns shaping organ allocation. Thus, we support the development of a similar model with suggested amendments. PMID:24166860

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

    PubMed Central

    Srie Vidhya Janani, E.; Ganesh Kumar, P.

    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. PMID:26495417

  9. Allocating Great Lakes forage bases in response to multiple demand

    USGS Publications Warehouse

    Brown, Edward H., Jr.; Busiahn, Thomas R.; Jones, Michael L.; Argyle, Ray L.

    1999-01-01

    Forage base allocation, which has become an important issue because of major changes in the fish communities and fisheries of the Great Lakes since the 1950s is examined and documented in this chapter. Management initiatives that were used to address the issue, and supporting research and development that provided new or improved methods of field sampling and analysis are also highlighted.

  10. Adjacency Matrix-Based Transmit Power Allocation Strategies in Wireless Sensor Networks

    PubMed Central

    Consolini, Luca; Medagliani, Paolo; Ferrari, Gianluigi

    2009-01-01

    In this paper, we present an innovative transmit power control scheme, based on optimization theory, for wireless sensor networks (WSNs) which use carrier sense multiple access (CSMA) with collision avoidance (CA) as medium access control (MAC) protocol. In particular, we focus on schemes where several remote nodes send data directly to a common access point (AP). Under the assumption of finite overall network transmit power and low traffic load, we derive the optimal transmit power allocation strategy that minimizes the packet error rate (PER) at the AP. This approach is based on modeling the CSMA/CA MAC protocol through a finite state machine and takes into account the network adjacency matrix, depending on the transmit power distribution and determining the network connectivity. It will be then shown that the transmit power allocation problem reduces to a convex constrained minimization problem. Our results show that, under the assumption of low traffic load, the power allocation strategy, which guarantees minimal delay, requires the maximization of network connectivity, which can be equivalently interpreted as the maximization of the number of non-zero entries of the adjacency matrix. The obtained theoretical results are confirmed by simulations for unslotted Zigbee WSNs. PMID:22346705

  11. Analysis and Simulation of the Dynamic Spectrum Allocation Based on Parallel Immune Optimization in Cognitive Wireless Networks

    PubMed Central

    Huixin, Wu; Duo, Mo; He, Li

    2014-01-01

    Spectrum allocation is one of the key issues to improve spectrum efficiency and has become the hot topic in the research of cognitive wireless network. This paper discusses the real-time feature and efficiency of dynamic spectrum allocation and presents a new spectrum allocation algorithm based on the master-slave parallel immune optimization model. The algorithm designs a new encoding scheme for the antibody based on the demand for convergence rate and population diversity. For improving the calculating efficiency, the antibody affinity in the population is calculated in multiple computing nodes at the same time. Simulation results show that the algorithm reduces the total spectrum allocation time and can achieve higher network profits. Compared with traditional serial algorithms, the algorithm proposed in this paper has better speedup ratio and parallel efficiency. PMID:25254255

  12. Stability Properties and Cross Coupling Performance of the Control Allocation Scheme CAPIO

    NASA Technical Reports Server (NTRS)

    Yildiz, Yildiray; Kolmanovsky, Ilya V.

    2010-01-01

    This paper presents a stability analysis and an application of a recently developed Control Allocator for recovery from Pilot Induced Oscillations (CAPIO). When actuators are rate-saturated due to either aggressive pilot commands, high gain ight control systems or some anomaly in the system, the effective delay in the control loop may increase. This effective delay increase manifests itself as a phase shift between the commanded and actual system signals and can instigate Pilot induced Oscillations (PIO). CAPIO reduces the e ective time delay by minimizing the phase shift between the commanded and the actual attitude accelerations. We present a stability analysis of CAPIO for a scalar system. In addition, we present simulation results for aircraft with cross-coupling which demonstrates the potential of CAPIO serving as an effective PIO handler in adverse conditions.

  13. FLDA: Latent Dirichlet Allocation Based Unsteady Flow Analysis.

    PubMed

    Hong, Fan; Lai, Chufan; Guo, Hanqi; Shen, Enya; Yuan, Xiaoru; Li, Sikun

    2014-12-01

    In this paper, we present a novel feature extraction approach called FLDA for unsteady flow fields based on Latent Dirichlet allocation (LDA) model. Analogous to topic modeling in text analysis, in our approach, pathlines and features in a given flow field are defined as documents and words respectively. Flow topics are then extracted based on Latent Dirichlet allocation. Different from other feature extraction methods, our approach clusters pathlines with probabilistic assignment, and aggregates features to meaningful topics at the same time. We build a prototype system to support exploration of unsteady flow field with our proposed LDA-based method. Interactive techniques are also developed to explore the extracted topics and to gain insight from the data. We conduct case studies to demonstrate the effectiveness of our proposed approach. PMID:26356968

  14. A Multi-layer Dynamic Model for Coordination Based Group Decision Making in Water Resource Allocation and Scheduling

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Zhang, Xingnan; Li, Chenming; Wang, Jianying

    Management of group decision-making is an important issue in water source management development. In order to overcome the defects in lacking of effective communication and cooperation in the existing decision-making models, this paper proposes a multi-layer dynamic model for coordination in water resource allocation and scheduling based group decision making. By introducing the scheme-recognized cooperative satisfaction index and scheme-adjusted rationality index, the proposed model can solve the problem of poor convergence of multi-round decision-making process in water resource allocation and scheduling. Furthermore, the problem about coordination of limited resources-based group decision-making process can be solved based on the effectiveness of distance-based group of conflict resolution. The simulation results show that the proposed model has better convergence than the existing models.

  15. Decentralized Service Allocation in a Broker Overlay Based Grid

    NASA Astrophysics Data System (ADS)

    Azab, Abdulrahman; Meling, Hein

    Grid computing is based on coordinated resource sharing in a dynamic environment of multi-institutional virtual organizations. Data exchanges, and service allocation, are challenging problems in the field of Grid computing. This is due to the decentralization of Grid systems. Building decentralized Grid systems with efficient resource management and software component mechanisms is a need for achieving the required efficiency and usability of Grid systems. In this work, a decentralized Grid system model is presented in which, the system is divided into virtual organizations each controlled by a broker. An overlay network of brokers is responsible for global resource management and managing allocation of services. Experimental results show that, the system achieves dependable performance with various loads of services, and broker failures.

  16. Student-Based Allocation to Enable School Choice. Schools in Crisis: Making Ends Meet

    ERIC Educational Resources Information Center

    Roza, Marguerite; Simburg, Suzanne

    2013-01-01

    One way districts can enable funding portability is with the use of student-based allocation formulas that allocate funds to districts and schools based on enrollment of students and student types. The student-based allocation model enables "pocketbook power," creating incentives for schools to attract students, keep full enrollment, and…

  17. [Optimal allocation of irrigation water resources based on systematical strategy].

    PubMed

    Cheng, Shuai; Zhang, Shu-qing

    2015-01-01

    With the development of the society and economy, as well as the rapid increase of population, more and more water is needed by human, which intensified the shortage of water resources. The scarcity of water resources and growing competition of water in different water use sectors reduce water availability for irrigation, so it is significant to plan and manage irrigation water resources scientifically and reasonably for improving water use efficiency (WUE) and ensuring food security. Many investigations indicate that WUE can be increased by optimization of water use. However, present studies focused primarily on a particular aspect or scale, which lack systematic analysis on the problem of irrigation water allocation. By summarizing previous related studies, especially those based on intelligent algorithms, this article proposed a multi-level, multi-scale framework for allocating irrigation water, and illustrated the basic theory of each component of the framework. Systematical strategy of optimal irrigation water allocation can not only control the total volume of irrigation water on the time scale, but also reduce water loss on the spatial scale. It could provide scientific basis and technical support for improving the irrigation water management level and ensuring the food security. PMID:25985685

  18. PIYAS-proceeding to intelligent service oriented memory allocation for flash based data centric sensor devices in wireless sensor networks.

    PubMed

    Rizvi, Sanam Shahla; Chung, Tae-Sun

    2010-01-01

    Flash memory has become a more widespread storage medium for modern wireless devices because of its effective characteristics like non-volatility, small size, light weight, fast access speed, shock resistance, high reliability and low power consumption. Sensor nodes are highly resource constrained in terms of limited processing speed, runtime memory, persistent storage, communication bandwidth and finite energy. Therefore, for wireless sensor networks supporting sense, store, merge and send schemes, an efficient and reliable file system is highly required with consideration of sensor node constraints. In this paper, we propose a novel log structured external NAND flash memory based file system, called Proceeding to Intelligent service oriented memorY Allocation for flash based data centric Sensor devices in wireless sensor networks (PIYAS). This is the extended version of our previously proposed PIYA [1]. The main goals of the PIYAS scheme are to achieve instant mounting and reduced SRAM space by keeping memory mapping information to a very low size of and to provide high query response throughput by allocation of memory to the sensor data by network business rules. The scheme intelligently samples and stores the raw data and provides high in-network data availability by keeping the aggregate data for a longer period of time than any other scheme has done before. We propose effective garbage collection and wear-leveling schemes as well. The experimental results show that PIYAS is an optimized memory management scheme allowing high performance for wireless sensor networks. PMID:22315541

  19. Three-dimensional compression scheme based on wavelet transform

    NASA Astrophysics Data System (ADS)

    Yang, Wu; Xu, Hui; Liao, Mengyang

    1999-03-01

    In this paper, a 3D compression method based on separable wavelet transform is discussed in detail. The most commonly used digital modalities generate multiple slices in a single examination, which are normally anatomically or physiologically correlated to each other. 3D wavelet compression methods can achieve more efficient compression by exploring the correlation between slices. The first step is based on a separable 3D wavelet transform. Considering the difference between pixel distances within a slice and those between slices, one biorthogonal Antoninin filter bank is applied within 2D slices and a second biorthogonal Villa4 filter bank on the slice direction. Then, S+P transform is applied in the low-resolution wavelet components and an optimal quantizer is presented after analysis of the quantization noise. We use an optimal bit allocation algorithm, which, instead of eliminating the coefficients of high-resolution components in smooth areas, minimizes the system reconstruction distortion at a given bit-rate. Finally, to remain high coding efficiency and adapt to different properties of each component, a comprehensive entropy coding method is proposed, in which arithmetic coding method is applied in high-resolution components and adaptive Huffman coding method in low-resolution components. Our experimental results are evaluated by several image measures and our 3D wavelet compression scheme is proved to be more efficient than 2D wavelet compression.

  20. A QoS aware resource allocation strategy for 3D A/V streaming in OFDMA based wireless systems.

    PubMed

    Chung, Young-Uk; Choi, Yong-Hoon; Park, Suwon; Lee, Hyukjoon

    2014-01-01

    Three-dimensional (3D) video is expected to be a "killer app" for OFDMA-based broadband wireless systems. The main limitation of 3D video streaming over a wireless system is the shortage of radio resources due to the large size of the 3D traffic. This paper presents a novel resource allocation strategy to address this problem. In the paper, the video-plus-depth 3D traffic type is considered. The proposed resource allocation strategy focuses on the relationship between 2D video and the depth map, handling them with different priorities. It is formulated as an optimization problem and is solved using a suboptimal heuristic algorithm. Numerical results show that the proposed scheme provides a better quality of service compared to conventional schemes. PMID:25250377

  1. A QoS Aware Resource Allocation Strategy for 3D A/V Streaming in OFDMA Based Wireless Systems

    PubMed Central

    Chung, Young-uk; Choi, Yong-Hoon; Park, Suwon; Lee, Hyukjoon

    2014-01-01

    Three-dimensional (3D) video is expected to be a “killer app” for OFDMA-based broadband wireless systems. The main limitation of 3D video streaming over a wireless system is the shortage of radio resources due to the large size of the 3D traffic. This paper presents a novel resource allocation strategy to address this problem. In the paper, the video-plus-depth 3D traffic type is considered. The proposed resource allocation strategy focuses on the relationship between 2D video and the depth map, handling them with different priorities. It is formulated as an optimization problem and is solved using a suboptimal heuristic algorithm. Numerical results show that the proposed scheme provides a better quality of service compared to conventional schemes. PMID:25250377

  2. Energy-efficient orthogonal frequency division multiplexing-based passive optical network based on adaptive sleep-mode control and dynamic bandwidth allocation

    NASA Astrophysics Data System (ADS)

    Zhang, Chongfu; Xiao, Nengwu; Chen, Chen; Yuan, Weicheng; Qiu, Kun

    2016-02-01

    We propose an energy-efficient orthogonal frequency division multiplexing-based passive optical network (OFDM-PON) using adaptive sleep-mode control and dynamic bandwidth allocation. In this scheme, a bidirectional-centralized algorithm named the receiver and transmitter accurate sleep control and dynamic bandwidth allocation (RTASC-DBA), which has an overall bandwidth scheduling policy, is employed to enhance the energy efficiency of the OFDM-PON. The RTASC-DBA algorithm is used in an optical line terminal (OLT) to control the sleep mode of an optical network unit (ONU) sleep and guarantee the quality of service of different services of the OFDM-PON. The obtained results show that, by using the proposed scheme, the average power consumption of the ONU is reduced by ˜40% when the normalized ONU load is less than 80%, compared with the average power consumption without using the proposed scheme.

  3. Multiview image compression based on LDV scheme

    NASA Astrophysics Data System (ADS)

    Battin, Benjamin; Niquin, Cédric; Vautrot, Philippe; Debons, Didier; Lucas, Laurent

    2011-03-01

    In recent years, we have seen several different approaches dealing with multiview compression. First, we can find the H264/MVC extension which generates quite heavy bitstreams when used on n-views autostereoscopic medias and does not allow inter-view reconstruction. Another solution relies on the MVD (MultiView+Depth) scheme which keeps p views (n > p > 1) and their associated depth-maps. This method is not suitable for multiview compression since it does not exploit the redundancy between the p views, moreover occlusion areas cannot be accurately filled. In this paper, we present our method based on the LDV (Layered Depth Video) approach which keeps one reference view with its associated depth-map and the n-1 residual ones required to fill occluded areas. We first perform a global per-pixel matching step (providing a good consistency between each view) in order to generate one unified-color RGB texture (where a unique color is devoted to all pixels corresponding to the same 3D-point, thus avoiding illumination artifacts) and a signed integer disparity texture. Next, we extract the non-redundant information and store it into two textures (a unified-color one and a disparity one) containing the reference and the n-1 residual views. The RGB texture is compressed with a conventional DCT or DWT-based algorithm and the disparity texture with a lossless dictionary algorithm. Then, we will discuss about the signal deformations generated by our approach.

  4. A quantum identification scheme based on polarization modulation

    NASA Astrophysics Data System (ADS)

    He, Guang-Qiang; Zeng, Gui-Hua

    2005-03-01

    A quantum identification scheme including registration and identification phases is proposed. The users' passwords are transmitted by qubit string and recorded as a set of quantum operators. The security of the proposed scheme is guaranteed by the no-cloning theorem. Based on photon polarization modulation, an experimental approach is also designed to implement our proposed scheme.

  5. Dynamic bandwidth allocation algorithms for local storage based VoD delivery: Comparison between single and dual receiver configurations

    NASA Astrophysics Data System (ADS)

    Abeywickrama, Sandu; Wong, Elaine

    2015-02-01

    The benefits of using distributed caching servers to optimize the traditional video-on-demand delivery have been extensively discussed in literature. In our previous work, we introduced a dual-receiver based dynamic bandwidth allocation algorithm to improve video-on-demand services using a local storage placed within the access network. The main drawback of this algorithm lies in the additional power consumption at the optical network unit that arises from using two receivers. In this paper, we present two novel single-receiver based dynamic bandwidth allocation algorithms to further optimize local storage aided video-on-demand over passive optical networks. The quality-of-service and power performances of the algorithms are critically analyzed using packet level simulations and formulation of power consumption models. We show that the energy-efficiency of a local storage based video-on-demand scheme can be increased without compromising the quality-of-service by the use of single receiver algorithms. Further, we compare the two newly introduced algorithms against dual-receiver based and without local storage schemes to find the most appropriate bandwidth allocation algorithm for local storage based video-on-demand delivery over passive optical networks.

  6. A mirror based scheme of a laser projection microscope

    NASA Astrophysics Data System (ADS)

    Gubarev, F. A.; Li, Lin; Klenovskii, M. S.

    2016-04-01

    The paper discusses the design of a laser projection microscope with a mirror-based scheme of image formation. It is shown that the laser projection microscope with the mirror-based scheme of image formation is well suited for distant objects monitoring. This scheme allowed obtaining a field of view of more than 3 cm at the distance of 4 m from the brightness amplifier

  7. Efficient GRASP based heuristics for the capacitated continuous location-allocation problem

    NASA Astrophysics Data System (ADS)

    Luis, Martino; Ramli, Mohammad Fadzli; Saputra, Ruswiati Surya

    2015-05-01

    This paper explores the np-hard capacitated continuous location-allocation problem, where the number of facilities to be located is specified and each of which has a constant capacity. Efficient greedy randomised adaptive search procedure (GRASP) based heuristics are proposed to tackle the problem. A scheme that applies the furthest distance rule (FDR) and self-adjusted threshold parameters to generate initial facility locations that are situated sparsely within GRASP framework is also put forward. The construction of the restricted candidate list (RCL) within GRASP is also guided by applying a concept of restricted regions that prevents new facility locations to be sited too close to the previous selected facility locations. The performance of the proposed GRASP heuristics is evaluated by conducting experiments using data sets taken from the literature typically used for the uncapacitated continuous location-allocation problem. The preliminary computational experiments show that the proposed methods provide encouraging solutions when compared to recently published papers. Some future research avenues on the subject are also briefly highlighted.

  8. A chaos secure communication scheme based on multiplication modulation

    NASA Astrophysics Data System (ADS)

    Fallahi, Kia; Leung, Henry

    2010-02-01

    A secure spread spectrum communication scheme using multiplication modulation is proposed. The proposed system multiplies the message by chaotic signal. The scheme does not need to know the initial condition of the chaotic signals and the receiver is based on an extended Kalman filter (EKF). This signal encryption scheme lends itself to cheap implementation and can therefore be used effectively for ensuring security and privacy in commercial consumer electronics products. To illustrate the effectiveness of the proposed scheme, a numerical example based on Genesio-Tesi system and also Chen dynamical system is presented and the results are compared.

  9. Bit-rate allocation for multiple video streams using a pricing-based mechanism.

    PubMed

    Tiwari, Mayank; Groves, Theodore; Cosman, Pamela

    2011-11-01

    We consider the problem of bit-rate allocation for multiple video users sharing a common transmission channel. Previously, overall quality of multiple users was improved by exploiting relative video complexity. Users with high-complexity video benefit at the expense of video quality reduction for other users with simpler videos. The quality of all users can be improved by collectively allocating the bit rate in a centralized fashion which requires sharing video information with a central controller. In this paper, we present an informationally decentralized bit-rate allocation for multiple users where a user only needs to inform his demand to an allocator. Each user separately calculates his bit-rate demand based on his video complexity and bit-rate price, where the bit-rate price is announced by the allocator. The allocator adjusts the bit-rate price for the next period based on the bit rate demanded by the users and the total available bit-rate supply. Simulation results show that all users improve their quality by the pricing-based decentralized bit-rate allocation method compared with their allocation when acting individually. The results of our proposed method are comparable to the centralized bit-rate allocation. PMID:21518661

  10. Quantum fully homomorphic encryption scheme based on universal quantum circuit

    NASA Astrophysics Data System (ADS)

    Liang, Min

    2015-08-01

    Fully homomorphic encryption enables arbitrary computation on encrypted data without decrypting the data. Here it is studied in the context of quantum information processing. Based on universal quantum circuit, we present a quantum fully homomorphic encryption (QFHE) scheme, which permits arbitrary quantum transformation on any encrypted data. The QFHE scheme is proved to be perfectly secure. In the scheme, the decryption key is different from the encryption key; however, the encryption key cannot be revealed. Moreover, the evaluation algorithm of the scheme is independent of the encryption key, so it is suitable for delegated quantum computing between two parties.

  11. Optimized entanglement purification schemes for modular based quantum computers

    NASA Astrophysics Data System (ADS)

    Krastanov, Stefan; Jiang, Liang

    The choice of entanglement purification scheme strongly depends on the fidelities of quantum gates and measurements, as well as the imperfection of initial entanglement. For instance, the purification scheme optimal at low gate fidelities may not necessarily be the optimal scheme at higher gate fidelities. We employ an evolutionary algorithm that efficiently optimizes the entanglement purification circuit for given system parameters. Such optimized purification schemes will boost the performance of entanglement purification, and consequently enhance the fidelity of teleportation-based non-local coupling gates, which is an indispensible building block for modular-based quantum computers. In addition, we study how these optimized purification schemes affect the resource overhead caused by error correction in modular based quantum computers.

  12. FRACTAL-BASED STOCHASTIC INTERPOLATION SCHEME IN SUBSURFACE HYDROLOGY

    EPA Science Inventory

    The need for a realistic and rational method for interpolating sparse data sets is wide spread. eal porosity and hydraulic conductivity data do not vary smoothly over space, so an interpolation scheme that preserves irregularity is desirable. uch a scheme based on the properties ...

  13. A FRACTAL-BASED STOCHASTIC INTERPOLATION SCHEME IN SUBSURFACE HYDROLOGY

    EPA Science Inventory

    The need for a realistic and rational method for interpolating sparse data sets is widespread. Real porosity and hydraulic conductivity data do not vary smoothly over space, so an interpolation scheme that preserves irregularity is desirable. Such a scheme based on the properties...

  14. Threshold signature scheme based on factoring and discrete logarithms

    NASA Astrophysics Data System (ADS)

    Mohamad, S. A.; Ismail, E. S.

    2012-09-01

    Recently, many documents or messages from an organization need to be signed by more than one person. For that reason, many threshold signatures based on various problems in number theory have been developed. In this paper, a threshold signature scheme based on two most popular number theory problems, namely factoring and discrete logarithms, was proposed. The advantage of this new scheme is based on the fact that it is very hard to solve both factoring and discrete logarithms problems simultaneously. This scheme is also shown secure against several attacks and requires a reasonable time complexity in both signing and verifying phase.

  15. Parallel and interlaced bandwidth allocation based on all-optical sub-banding WDM-OFDM PON network

    NASA Astrophysics Data System (ADS)

    Zou, Shumin; Zheng, Xi; Fang, Wuliang; Li, Xinying; Zhang, Junwen; Shao, Yufeng; Chi, Nan

    2010-12-01

    For the first time, we propose and demonstrate a novel three-level Signal allocation scheme OFDM PON architecture which makes the best use of OFDM characteristics. In the architecture, we produce five-carrier signal optically by MZM, use odd carriers modulating downlink data and retain even carriers for uplink data. Multiple signal distribution methods can be switched flexibly. By simulation, a small PON systems with four ONU based on this architecture was realized. Both the downlink and uplink transmission adopt 4-QAM-OFDM signal. The transmission rate will be demonstrated to exceed 10Gbit/s.

  16. Classification Based on Tree-Structured Allocation Rules

    ERIC Educational Resources Information Center

    Vaughn, Brandon K.; Wang, Qui

    2008-01-01

    The authors consider the problem of classifying an unknown observation into 1 of several populations by using tree-structured allocation rules. Although many parametric classification procedures are robust to certain assumption violations, there is need for classification procedures that can be used regardless of the group-conditional…

  17. Triangle based TVD schemes for hyperbolic conservation laws

    NASA Technical Reports Server (NTRS)

    Durlofsky, Louis J.; Osher, Stanley; Engquist, Bjorn

    1990-01-01

    A triangle based total variation diminishing (TVD) scheme for the numerical approximation of hyperbolic conservation laws in two space dimensions is constructed. The novelty of the scheme lies in the nature of the preprocessing of the cell averaged data, which is accomplished via a nearest neighbor linear interpolation followed by a slope limiting procedures. Two such limiting procedures are suggested. The resulting method is considerably more simple than other triangle based non-oscillatory approximations which, like this scheme, approximate the flux up to second order accuracy. Numerical results for linear advection and Burgers' equation are presented.

  18. Impact-Based Area Allocation for Yield Optimization in Integrated Circuits

    NASA Astrophysics Data System (ADS)

    Abraham, Billion; Widodo, Arif; Chen, Poki

    2016-06-01

    In analog integrated circuit (IC) layout, area allocation is a very important issue for achieving good mismatch cancellation. However, most IC layout papers focus only on layout strategy to reduce systematic mismatch. In 2006, an outstanding paper presenting area allocation strategy was published to introduce technique for random mismatch reduction. Instead of using general theoretical study to prove the strategy, this research presented close-to-optimum simulations only on case-bycase basis. The impact-based area allocation for yield optimization in integrated circuits is proposed in this chapter. To demonstrate the corresponding strategy, not only a theoretical analysis but also an integral nonlinearity-based yield simulation will be given to derive optimum area allocation for binary weighted current steering digital-to-analog converter (DAC). The result will be concluded to convince IC designers how to allocate area for critical devices in an optimum way.

  19. Splitting based finite volume schemes for ideal MHD equations

    NASA Astrophysics Data System (ADS)

    Fuchs, F. G.; Mishra, S.; Risebro, N. H.

    2009-02-01

    We design finite volume schemes for the equations of ideal magnetohydrodynamics (MHD) and based on splitting these equations into a fluid part and a magnetic induction part. The fluid part leads to an extended Euler system with magnetic forces as source terms. This set of equations are approximated by suitable two- and three-wave HLL solvers. The magnetic part is modeled by the magnetic induction equations which are approximated using stable upwind schemes devised in a recent paper [F. Fuchs, K.H. Karlsen, S. Mishra, N.H. Risebro, Stable upwind schemes for the Magnetic Induction equation. Math. Model. Num. Anal., Available on conservation laws preprint server, submitted for publication, URL: ]. These two sets of schemes can be combined either component by component, or by using an operator splitting procedure to obtain a finite volume scheme for the MHD equations. The resulting schemes are simple to design and implement. These schemes are compared with existing HLL type and Roe type schemes for MHD equations in a series of numerical experiments. These tests reveal that the proposed schemes are robust and have a greater numerical resolution than HLL type solvers, particularly in several space dimensions. In fact, the numerical resolution is comparable to that of the Roe scheme on most test problems with the computational cost being at the level of a HLL type solver. Furthermore, the schemes are remarkably stable even at very fine mesh resolutions and handle the divergence constraint efficiently with low divergence errors.

  20. An expert system based intelligent control scheme for space bioreactors

    NASA Technical Reports Server (NTRS)

    San, Ka-Yiu

    1988-01-01

    An expert system based intelligent control scheme is being developed for the effective control and full automation of bioreactor systems in space. The scheme developed will have the capability to capture information from various resources including heuristic information from process researchers and operators. The knowledge base of the expert system should contain enough expertise to perform on-line system identification and thus be able to adapt the controllers accordingly with minimal human supervision.

  1. Rate Adaptive Based Resource Allocation with Proportional Fairness Constraints in OFDMA Systems

    PubMed Central

    Yin, Zhendong; Zhuang, Shufeng; Wu, Zhilu; Ma, Bo

    2015-01-01

    Orthogonal frequency division multiple access (OFDMA), which is widely used in the wireless sensor networks, allows different users to obtain different subcarriers according to their subchannel gains. Therefore, how to assign subcarriers and power to different users to achieve a high system sum rate is an important research area in OFDMA systems. In this paper, the focus of study is on the rate adaptive (RA) based resource allocation with proportional fairness constraints. Since the resource allocation is a NP-hard and non-convex optimization problem, a new efficient resource allocation algorithm ACO-SPA is proposed, which combines ant colony optimization (ACO) and suboptimal power allocation (SPA). To reduce the computational complexity, the optimization problem of resource allocation in OFDMA systems is separated into two steps. For the first one, the ant colony optimization algorithm is performed to solve the subcarrier allocation. Then, the suboptimal power allocation algorithm is developed with strict proportional fairness, and the algorithm is based on the principle that the sums of power and the reciprocal of channel-to-noise ratio for each user in different subchannels are equal. To support it, plenty of simulation results are presented. In contrast with root-finding and linear methods, the proposed method provides better performance in solving the proportional resource allocation problem in OFDMA systems. PMID:26426016

  2. Rate Adaptive Based Resource Allocation with Proportional Fairness Constraints in OFDMA Systems.

    PubMed

    Yin, Zhendong; Zhuang, Shufeng; Wu, Zhilu; Ma, Bo

    2015-01-01

    Orthogonal frequency division multiple access (OFDMA), which is widely used in the wireless sensor networks, allows different users to obtain different subcarriers according to their subchannel gains. Therefore, how to assign subcarriers and power to different users to achieve a high system sum rate is an important research area in OFDMA systems. In this paper, the focus of study is on the rate adaptive (RA) based resource allocation with proportional fairness constraints. Since the resource allocation is a NP-hard and non-convex optimization problem, a new efficient resource allocation algorithm ACO-SPA is proposed, which combines ant colony optimization (ACO) and suboptimal power allocation (SPA). To reduce the computational complexity, the optimization problem of resource allocation in OFDMA systems is separated into two steps. For the first one, the ant colony optimization algorithm is performed to solve the subcarrier allocation. Then, the suboptimal power allocation algorithm is developed with strict proportional fairness, and the algorithm is based on the principle that the sums of power and the reciprocal of channel-to-noise ratio for each user in different subchannels are equal. To support it, plenty of simulation results are presented. In contrast with root-finding and linear methods, the proposed method provides better performance in solving the proportional resource allocation problem in OFDMA systems. PMID:26426016

  3. A novel deployment scheme based on three-dimensional coverage model for wireless sensor networks.

    PubMed

    Xiao, Fu; Yang, Yang; Wang, Ruchuan; Sun, Lijuan

    2014-01-01

    Coverage pattern and deployment strategy are directly related to the optimum allocation of limited resources for wireless sensor networks, such as energy of nodes, communication bandwidth, and computing power, and quality improvement is largely determined by these for wireless sensor networks. A three-dimensional coverage pattern and deployment scheme are proposed in this paper. Firstly, by analyzing the regular polyhedron models in three-dimensional scene, a coverage pattern based on cuboids is proposed, and then relationship between coverage and sensor nodes' radius is deduced; also the minimum number of sensor nodes to maintain network area's full coverage is calculated. At last, sensor nodes are deployed according to the coverage pattern after the monitor area is subdivided into finite 3D grid. Experimental results show that, compared with traditional random method, sensor nodes number is reduced effectively while coverage rate of monitor area is ensured using our coverage pattern and deterministic deployment scheme. PMID:25045747

  4. On System Engineering a Barter-Based Re-allocation of Space System Key Development Resources

    NASA Astrophysics Data System (ADS)

    Kosmann, William J.

    NASA has had a decades-long problem with cost growth during the development of space science missions. Numerous agency-sponsored studies have produced average mission level development cost growths ranging from 23 to 77%. A new study of 26 historical NASA science instrument set developments using expert judgment to re-allocate key development resources has an average cost growth of 73.77%. Twice in history, during the Cassini and EOS-Terra science instrument developments, a barter-based mechanism has been used to re-allocate key development resources. The mean instrument set development cost growth was -1.55%. Performing a bivariate inference on the means of these two distributions, there is statistical evidence to support the claim that using a barter-based mechanism to re-allocate key instrument development resources will result in a lower expected cost growth than using the expert judgment approach. Agent-based discrete event simulation is the natural way to model a trade environment. A NetLogo agent-based barter-based simulation of science instrument development was created. The agent-based model was validated against the Cassini historical example, as the starting and ending instrument development conditions are available. The resulting validated agent-based barter-based science instrument resource re-allocation simulation was used to perform 300 instrument development simulations, using barter to re-allocate development resources. The mean cost growth was -3.365%. A bivariate inference on the means was performed to determine that additional significant statistical evidence exists to support a claim that using barter-based resource re-allocation will result in lower expected cost growth, with respect to the historical expert judgment approach. Barter-based key development resource re-allocation should work on science spacecraft development as well as it has worked on science instrument development. A new study of 28 historical NASA science spacecraft

  5. Neural Network Based Modeling and Analysis of LP Control Surface Allocation

    NASA Technical Reports Server (NTRS)

    Langari, Reza; Krishnakumar, Kalmanje; Gundy-Burlet, Karen

    2003-01-01

    This paper presents an approach to interpretive modeling of LP based control allocation in intelligent flight control. The emphasis is placed on a nonlinear interpretation of the LP allocation process as a static map to support analytical study of the resulting closed loop system, albeit in approximate form. The approach makes use of a bi-layer neural network to capture the essential functioning of the LP allocation process. It is further shown via Lyapunov based analysis that under certain relatively mild conditions the resulting closed loop system is stable. Some preliminary conclusions from a study at Ames are stated and directions for further research are given at the conclusion of the paper.

  6. Robust Audio Watermarking Scheme Based on Deterministic Plus Stochastic Model

    NASA Astrophysics Data System (ADS)

    Dhar, Pranab Kumar; Kim, Cheol Hong; Kim, Jong-Myon

    Digital watermarking has been widely used for protecting digital contents from unauthorized duplication. This paper proposes a new watermarking scheme based on spectral modeling synthesis (SMS) for copyright protection of digital contents. SMS defines a sound as a combination of deterministic events plus a stochastic component that makes it possible for a synthesized sound to attain all of the perceptual characteristics of the original sound. In our proposed scheme, watermarks are embedded into the highest prominent peak of the magnitude spectrum of each non-overlapping frame in peak trajectories. Simulation results indicate that the proposed watermarking scheme is highly robust against various kinds of attacks such as noise addition, cropping, re-sampling, re-quantization, and MP3 compression and achieves similarity values ranging from 17 to 22. In addition, our proposed scheme achieves signal-to-noise ratio (SNR) values ranging from 29 dB to 30 dB.

  7. Communication scheme based on evolutionary spatial 2×2 games

    NASA Astrophysics Data System (ADS)

    Ziaukas, Pranas; Ragulskis, Tautvydas; Ragulskis, Minvydas

    2014-06-01

    A visual communication scheme based on evolutionary spatial 2×2 games is proposed in this paper. Self-organizing patterns induced by complex interactions between competing individuals are exploited for hiding and transmitting secret visual information. Properties of the proposed communication scheme are discussed in details. It is shown that the hiding capacity of the system (the minimum size of the detectable primitives and the minimum distance between two primitives) is sufficient for the effective transmission of digital dichotomous images. Also, it is demonstrated that the proposed communication scheme is resilient to time backwards, plain image attacks and is highly sensitive to perturbations of private and public keys. Several computational experiments are used to demonstrate the effectiveness of the proposed communication scheme.

  8. Model-based metrics of human-automation function allocation in complex work environments

    NASA Astrophysics Data System (ADS)

    Kim, So Young

    issues with function allocation. Then, based on the eight issues, eight types of metrics are established. The purpose of these metrics is to assess the extent to which each issue exists with a given function allocation. Specifically, the eight types of metrics assess workload, coherency of a function allocation, mismatches between responsibility and authority, interruptive automation, automation boundary conditions, human adaptation to context, stability of the human's work environment, and mission performance. Finally, to validate the modeling framework and the metrics, a case study was conducted modeling four different function allocations between a pilot and flight deck automation during the arrival and approach phases of flight. A range of pilot cognitive control modes and maximum human taskload limits were also included in the model. The metrics were assessed for these four function allocations and analyzed to validate capability of the metrics to identify important issues in given function allocations. In addition, the design insights provided by the metrics are highlighted. This thesis concludes with a discussion of mechanisms for further validating the modeling framework and function allocation metrics developed here, and highlights where these developments can be applied in research and in the design of function allocations in complex work environments such as aviation operations.

  9. Integrated optical 3D digital imaging based on DSP scheme

    NASA Astrophysics Data System (ADS)

    Wang, Xiaodong; Peng, Xiang; Gao, Bruce Z.

    2008-03-01

    We present a scheme of integrated optical 3-D digital imaging (IO3DI) based on digital signal processor (DSP), which can acquire range images independently without PC support. This scheme is based on a parallel hardware structure with aid of DSP and field programmable gate array (FPGA) to realize 3-D imaging. In this integrated scheme of 3-D imaging, the phase measurement profilometry is adopted. To realize the pipeline processing of the fringe projection, image acquisition and fringe pattern analysis, we present a multi-threads application program that is developed under the environment of DSP/BIOS RTOS (real-time operating system). Since RTOS provides a preemptive kernel and powerful configuration tool, with which we are able to achieve a real-time scheduling and synchronization. To accelerate automatic fringe analysis and phase unwrapping, we make use of the technique of software optimization. The proposed scheme can reach a performance of 39.5 f/s (frames per second), so it may well fit into real-time fringe-pattern analysis and can implement fast 3-D imaging. Experiment results are also presented to show the validity of proposed scheme.

  10. FOR Allocation to Distribution Systems based on Credible Improvement Potential (CIP)

    NASA Astrophysics Data System (ADS)

    Tiwary, Aditya; Arya, L. D.; Arya, Rajesh; Choube, S. C.

    2016-06-01

    This paper describes an algorithm for forced outage rate (FOR) allocation to each section of an electrical distribution system subject to satisfaction of reliability constraints at each load point. These constraints include threshold values of basic reliability indices, for example, failure rate, interruption duration and interruption duration per year at load points. Component improvement potential measure has been used for FOR allocation. Component with greatest magnitude of credible improvement potential (CIP) measure is selected for improving reliability performance. The approach adopted is a monovariable method where one component is selected for FOR allocation and in the next iteration another component is selected for FOR allocation based on the magnitude of CIP. The developed algorithm is implemented on sample radial distribution system.

  11. A simple model to optimize resource allocations when expanding the faculty research base: a case study.

    PubMed

    Joiner, Keith A

    2009-01-01

    Construction of new biomedical research facilities has outpaced the funding sources for faculty to occupy those facilities. This puts a premium on the efficient allocation of central resources for faculty recruitment. The author developed a mathematical model to determine the optimal structure (dollars, space) for allocating resource packages when recruiting new faculty, based on expected financial returns from those faculty. Surprisingly, the optimal strategy was to allocate homogeneous recruitment packages, independent of the recruited faculty member's rank or the individual's expected revenue generation. Optimization results were used to allocate recruitment packages to new department head and center directors in the University of Arizona College of Medicine during the last four years (2005-2008). At any institution that uses this model, appropriate distribution of facilities and administrative revenues at the institution is needed to equitably balance the costs and benefits associated with faculty expansion. PMID:19116472

  12. Antenna Allocation in MIMO Radar with Widely Separated Antennas for Multi-Target Detection

    PubMed Central

    Gao, Hao; Wang, Jian; Jiang, Chunxiao; Zhang, Xudong

    2014-01-01

    In this paper, we explore a new resource called multi-target diversity to optimize the performance of multiple input multiple output (MIMO) radar with widely separated antennas for detecting multiple targets. In particular, we allocate antennas of the MIMO radar to probe different targets simultaneously in a flexible manner based on the performance metric of relative entropy. Two antenna allocation schemes are proposed. In the first scheme, each antenna is allocated to illuminate a proper target over the entire illumination time, so that the detection performance of each target is guaranteed. The problem is formulated as a minimum makespan scheduling problem in the combinatorial optimization framework. Antenna allocation is implemented through a branch-and-bound algorithm and an enhanced factor 2 algorithm. In the second scheme, called antenna-time allocation, each antenna is allocated to illuminate different targets with different illumination time. Both antenna allocation and time allocation are optimized based on illumination probabilities. Over a large range of transmitted power, target fluctuations and target numbers, both of the proposed antenna allocation schemes outperform the scheme without antenna allocation. Moreover, the antenna-time allocation scheme achieves a more robust detection performance than branch-and-bound algorithm and the enhanced factor 2 algorithm when the target number changes. PMID:25350505

  13. Improved Readout Scheme for SQUID-Based Thermometry

    NASA Technical Reports Server (NTRS)

    Penanen, Konstantin

    2007-01-01

    An improved readout scheme has been proposed for high-resolution thermometers, (HRTs) based on the use of superconducting quantum interference devices (SQUIDs) to measure temperature- dependent magnetic susceptibilities. The proposed scheme would eliminate counting ambiguities that arise in the conventional scheme, while maintaining the superior magnetic-flux sensitivity of the conventional scheme. The proposed scheme is expected to be especially beneficial for HRT-based temperature control of multiplexed SQUIDbased bolometer sensor arrays. SQUID-based HRTs have become standard for measuring and controlling temperatures in the sub-nano-Kelvin temperature range in a broad range of low-temperature scientific and engineering applications. A typical SQUIDbased HRT that utilizes the conventional scheme includes a coil wound on a core made of a material that has temperature- dependent magnetic susceptibility in the temperature range of interest. The core and the coil are placed in a DC magnetic field provided either by a permanent magnet or as magnetic flux inside a superconducting outer wall. The aforementioned coil is connected to an input coil of a SQUID. Changes in temperature lead to changes in the susceptibility of the core and to changes in the magnetic flux detected by the SQUID. The SQUID readout instrumentation is capable of measuring magnetic-flux changes that correspond to temperature changes down to a noise limit .0.1 nK/Hz1/2. When the flux exceeds a few fundamental flux units, which typically corresponds to a temperature of .100 nK, the SQUID is reset. The temperature range can be greatly expanded if the reset events are carefully tracked and counted, either by a computer running appropriate software or by a dedicated piece of hardware.

  14. Wavelet based hierarchical coding scheme for radar image compression

    NASA Astrophysics Data System (ADS)

    Sheng, Wen; Jiao, Xiaoli; He, Jifeng

    2007-12-01

    This paper presents a wavelet based hierarchical coding scheme for radar image compression. Radar signal is firstly quantized to digital signal, and reorganized as raster-scanned image according to radar's repeated period frequency. After reorganization, the reformed image is decomposed to image blocks with different frequency band by 2-D wavelet transformation, each block is quantized and coded by the Huffman coding scheme. A demonstrating system is developed, showing that under the requirement of real time processing, the compression ratio can be very high, while with no significant loss of target signal in restored radar image.

  15. Three-party remote state preparation schemes based on entanglement

    NASA Astrophysics Data System (ADS)

    Zhou, Nan-Run; Cheng, Hu-Lai; Tao, Xiang-Yang; Gong, Li-Hua

    2013-11-01

    By exploiting the entanglement correlation in quantum mechanics, two three-party remote state preparation (RSP) schemes are proposed. One is three-party remote preparation of a single-particle quantum state, and the other is three-party remote preparation of a two-particle entangled state. In the proposed schemes, the sender Alice knows the quantum states to be prepared, while the receivers Bob and Charlie do not know the quantum states; Alice performs measurement and unitary operations on her own particles with two three-particle GHZ states as the quantum channel. According to Alice's measurement results, Bob and Charlie measure their own particles on the corresponding quantum measurement bases and perform unitary operations on the corresponding particles to reconstruct the quantum states, respectively. Compared with multiparty joint remote preparation and two-party RSP of a quantum state, the proposed schemes realize quantum multicast communication successfully, which enables Bob and Charlie to obtain the prepared quantum states simultaneously in the case of just knowing Alice's measurement results, while Bob and Charlie do not know each other's prepared quantum states. It is shown that only three classical bits are required for the two proposed RSP schemes when Bob and Alice introduce an auxiliary particle, respectively, and the proposed schemes are secure after the quantum channel authentication.

  16. An ICA based MIMO-OFDM VLC scheme

    NASA Astrophysics Data System (ADS)

    Jiang, Fangqing; Deng, Honggui; Xiao, Wei; Tao, Shaohua; Zhu, Kaicheng

    2015-07-01

    In this paper, we propose a novel ICA based MIMO-OFDM VLC scheme, where ICA is applied to convert the MIMO-OFDM channel into several SISO-OFDM channels to reduce computational complexity in channel estimation, without any spectral overhead. Besides, the FM is first investigated to further modulate the OFDM symbols to eliminate the correlation of the signals, so as to improve the separation performance of the ICA algorithm. In the 4×4MIMO-OFDM VLC simulation experiment, LOS path and NLOS paths are both considered, each transmitting signal at 100 Mb/s. Simulation results show that the BER of the proposed scheme reaches the 10-5 level at SNR=20 dB, which is a large improvement compared to the traditional schemes.

  17. New optical scheme for a polarimetric-based glucose sensor

    NASA Technical Reports Server (NTRS)

    Ansari, Rafat R.; Bockle, Stefan; Rovati, Luigi

    2004-01-01

    A new optical scheme to detect glucose concentration in the aqueous humor of the eye is presented. The ultimate aim is to apply this technique in designing a new instrument for, routinely and frequently, noninvasively monitoring blood glucose levels in diabetic patients without contact (no index matching) between the eye and the instrument. The optical scheme exploits the Brewster reflection of circularly polarized light off of the lens of the eye. Theoretically, this reflected linearly polarized light on its way to the detector is expected to rotate its state of polarization, owing to the presence of glucose molecules in the aqueous humor of a patient's eye. An experimental laboratory setup based on this scheme was designed and tested by measuring a range of known concentrations of glucose solutions dissolved in water. (c) 2004 Society of Photo-Optical Instrumentation Engineers.

  18. Comparing administered and market-based water allocation systems using an agent-based modeling approach

    NASA Astrophysics Data System (ADS)

    Zhao, J.; Cai, X.; Wang, Z.

    2009-12-01

    It also has been well recognized that market-based systems can have significant advantages over administered systems for water allocation. However there are not many successful water markets around the world yet and administered systems exist commonly in water allocation management practice. This paradox has been under discussion for decades and still calls for attention for both research and practice. This paper explores some insights for the paradox and tries to address why market systems have not been widely implemented for water allocation. Adopting the theory of agent-based system we develop a consistent analytical model to interpret both systems. First we derive some theorems based on the analytical model, with respect to the necessary conditions for economic efficiency of water allocation. Following that the agent-based model is used to illustrate the coherence and difference between administered and market-based systems. The two systems are compared from three aspects: 1) the driving forces acting on the system state, 2) system efficiency, and 3) equity. Regarding economic efficiency, penalty on the violation of water use permits (or rights) under an administered system can lead to system-wide economic efficiency, as well as being acceptable by some agents, which follows the theory of the so-call rational violation. Ideal equity will be realized if penalty equals incentive with an administered system and if transaction costs are zero with a market system. The performances of both agents and the over system are explained with an administered system and market system, respectively. The performances of agents are subject to different mechanisms of interactions between agents under the two systems. The system emergency (i.e., system benefit, equilibrium market price, etc), resulting from the performance at the agent level, reflects the different mechanism of the two systems, the “invisible hand” with the market system and administrative measures (penalty

  19. Developing Subdomain Allocation Algorithms Based on Spatial and Communicational Constraints to Accelerate Dust Storm Simulation.

    PubMed

    Gui, Zhipeng; Yu, Manzhu; Yang, Chaowei; Jiang, Yunfeng; Chen, Songqing; Xia, Jizhe; Huang, Qunying; Liu, Kai; Li, Zhenlong; Hassan, Mohammed Anowarul; Jin, Baoxuan

    2016-01-01

    Dust storm has serious disastrous impacts on environment, human health, and assets. The developments and applications of dust storm models have contributed significantly to better understand and predict the distribution, intensity and structure of dust storms. However, dust storm simulation is a data and computing intensive process. To improve the computing performance, high performance computing has been widely adopted by dividing the entire study area into multiple subdomains and allocating each subdomain on different computing nodes in a parallel fashion. Inappropriate allocation may introduce imbalanced task loads and unnecessary communications among computing nodes. Therefore, allocation is a key factor that may impact the efficiency of parallel process. An allocation algorithm is expected to consider the computing cost and communication cost for each computing node to minimize total execution time and reduce overall communication cost for the entire simulation. This research introduces three algorithms to optimize the allocation by considering the spatial and communicational constraints: 1) an Integer Linear Programming (ILP) based algorithm from combinational optimization perspective; 2) a K-Means and Kernighan-Lin combined heuristic algorithm (K&K) integrating geometric and coordinate-free methods by merging local and global partitioning; 3) an automatic seeded region growing based geometric and local partitioning algorithm (ASRG). The performance and effectiveness of the three algorithms are compared based on different factors. Further, we adopt the K&K algorithm as the demonstrated algorithm for the experiment of dust model simulation with the non-hydrostatic mesoscale model (NMM-dust) and compared the performance with the MPI default sequential allocation. The results demonstrate that K&K method significantly improves the simulation performance with better subdomain allocation. This method can also be adopted for other relevant atmospheric and numerical

  20. Developing Subdomain Allocation Algorithms Based on Spatial and Communicational Constraints to Accelerate Dust Storm Simulation

    PubMed Central

    Gui, Zhipeng; Yu, Manzhu; Yang, Chaowei; Jiang, Yunfeng; Chen, Songqing; Xia, Jizhe; Huang, Qunying; Liu, Kai; Li, Zhenlong; Hassan, Mohammed Anowarul; Jin, Baoxuan

    2016-01-01

    Dust storm has serious disastrous impacts on environment, human health, and assets. The developments and applications of dust storm models have contributed significantly to better understand and predict the distribution, intensity and structure of dust storms. However, dust storm simulation is a data and computing intensive process. To improve the computing performance, high performance computing has been widely adopted by dividing the entire study area into multiple subdomains and allocating each subdomain on different computing nodes in a parallel fashion. Inappropriate allocation may introduce imbalanced task loads and unnecessary communications among computing nodes. Therefore, allocation is a key factor that may impact the efficiency of parallel process. An allocation algorithm is expected to consider the computing cost and communication cost for each computing node to minimize total execution time and reduce overall communication cost for the entire simulation. This research introduces three algorithms to optimize the allocation by considering the spatial and communicational constraints: 1) an Integer Linear Programming (ILP) based algorithm from combinational optimization perspective; 2) a K-Means and Kernighan-Lin combined heuristic algorithm (K&K) integrating geometric and coordinate-free methods by merging local and global partitioning; 3) an automatic seeded region growing based geometric and local partitioning algorithm (ASRG). The performance and effectiveness of the three algorithms are compared based on different factors. Further, we adopt the K&K algorithm as the demonstrated algorithm for the experiment of dust model simulation with the non-hydrostatic mesoscale model (NMM-dust) and compared the performance with the MPI default sequential allocation. The results demonstrate that K&K method significantly improves the simulation performance with better subdomain allocation. This method can also be adopted for other relevant atmospheric and numerical

  1. Needs-Based Resource Allocation in Education via Formula Funding of Schools.

    ERIC Educational Resources Information Center

    Ross, Kenneth N., Ed.; Levacic, Rosalind, Ed.

    This book explores a range of conceptual, methodological, and empirical issues concerned with the application of needs-based resource allocation in education via formula funding of schools. The notion of "needs-based formula funding" employed in this discussion refers to the impartial application of an agreed set of explicit rules to allocate…

  2. Word Learning and Attention Allocation Based on Word Class and Category Knowledge

    ERIC Educational Resources Information Center

    Hupp, Julie M.

    2015-01-01

    Attention allocation in word learning may vary developmentally based on the novelty of the object. It has been suggested that children differentially learn verbs based on the novelty of the agent, but adults do not because they automatically infer the object's category and thus treat it like a familiar object. The current research examined…

  3. On Cryptographic Schemes Based on Discrete Logarithms and Factoring

    NASA Astrophysics Data System (ADS)

    Joye, Marc

    At CRYPTO 2003, Rubin and Silverberg introduced the concept of torus-based cryptography over a finite field. We extend their setting to the ring of integers modulo N. We so obtain compact representations for cryptographic systems that base their security on the discrete logarithm problem and the factoring problem. This results in smaller key sizes and substantial savings in memory and bandwidth. But unlike the case of finite fields, analogous trace-based compression methods cannot be adapted to accommodate our extended setting when the underlying systems require more than a mere exponentiation. As an application, we present an improved, torus-based implementation of the ACJT group signature scheme.

  4. Research on Multirobot Pursuit Task Allocation Algorithm Based on Emotional Cooperation Factor

    PubMed Central

    Fang, Baofu; Chen, Lu; Wang, Hao; Dai, Shuanglu; Zhong, Qiubo

    2014-01-01

    Multirobot task allocation is a hot issue in the field of robot research. A new emotional model is used with the self-interested robot, which gives a new way to measure self-interested robots' individual cooperative willingness in the problem of multirobot task allocation. Emotional cooperation factor is introduced into self-interested robot; it is updated based on emotional attenuation and external stimuli. Then a multirobot pursuit task allocation algorithm is proposed, which is based on emotional cooperation factor. Combined with the two-step auction algorithm recruiting team leaders and team collaborators, set up pursuit teams, and finally use certain strategies to complete the pursuit task. In order to verify the effectiveness of this algorithm, some comparing experiments have been done with the instantaneous greedy optimal auction algorithm; the results of experiments show that the total pursuit time and total team revenue can be optimized by using this algorithm. PMID:25152925

  5. Resource management scheme based on ubiquitous data analysis.

    PubMed

    Lee, Heung Ki; Jung, Jaehee; Yi, Gangman

    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

  6. 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

  7. Enhancing Community Detection By Affinity-based Edge Weighting Scheme

    SciTech Connect

    Yoo, Andy; Sanders, Geoffrey; Henson, Van; Vassilevski, Panayot

    2015-10-05

    Community detection refers to an important graph analytics problem of finding a set of densely-connected subgraphs in a graph and has gained a great deal of interest recently. The performance of current community detection algorithms is limited by an inherent constraint of unweighted graphs that offer very little information on their internal community structures. In this paper, we propose a new scheme to address this issue that weights the edges in a given graph based on recently proposed vertex affinity. The vertex affinity quantifies the proximity between two vertices in terms of their clustering strength, and therefore, it is ideal for graph analytics applications such as community detection. We also demonstrate that the affinity-based edge weighting scheme can improve the performance of community detection algorithms significantly.

  8. Efficient Allocation of Resources for Defense of Spatially Distributed Networks Using Agent-Based Simulation.

    PubMed

    Kroshl, William M; Sarkani, Shahram; Mazzuchi, Thomas A

    2015-09-01

    This article presents ongoing research that focuses on efficient allocation of defense resources to minimize the damage inflicted on a spatially distributed physical network such as a pipeline, water system, or power distribution system from an attack by an active adversary, recognizing the fundamental difference between preparing for natural disasters such as hurricanes, earthquakes, or even accidental systems failures and the problem of allocating resources to defend against an opponent who is aware of, and anticipating, the defender's efforts to mitigate the threat. Our approach is to utilize a combination of integer programming and agent-based modeling to allocate the defensive resources. We conceptualize the problem as a Stackelberg "leader follower" game where the defender first places his assets to defend key areas of the network, and the attacker then seeks to inflict the maximum damage possible within the constraints of resources and network structure. The criticality of arcs in the network is estimated by a deterministic network interdiction formulation, which then informs an evolutionary agent-based simulation. The evolutionary agent-based simulation is used to determine the allocation of resources for attackers and defenders that results in evolutionary stable strategies, where actions by either side alone cannot increase its share of victories. We demonstrate these techniques on an example network, comparing the evolutionary agent-based results to a more traditional, probabilistic risk analysis (PRA) approach. Our results show that the agent-based approach results in a greater percentage of defender victories than does the PRA-based approach. PMID:25683347

  9. Revisiting Quantum Authentication Scheme Based on Entanglement Swapping

    NASA Astrophysics Data System (ADS)

    Naseri, Mosayeb

    2016-05-01

    The crucial issue of quantum communication protocol is its security. In this paper, the security of the Quantum Authentication Scheme Based on Entanglement Swapping proposed by Penghao et al. (Int J Theor Phys., doi: 10.1007/s10773-015-2662-7) is reanalyzed. It is shown that the original does not complete the task of quantum authentication and communication securely. Furthermore a simple improvement on the protocol is proposed.

  10. Energy-saving scheme based on downstream packet scheduling in ethernet passive optical networks

    NASA Astrophysics Data System (ADS)

    Zhang, Lincong; Liu, Yejun; Guo, Lei; Gong, Xiaoxue

    2013-03-01

    With increasing network sizes, the energy consumption of Passive Optical Networks (PONs) has grown significantly. Therefore, it is important to design effective energy-saving schemes in PONs. Generally, energy-saving schemes have focused on sleeping the low-loaded Optical Network Units (ONUs), which tends to bring large packet delays. Further, the traditional ONU sleep modes are not capable of sleeping the transmitter and receiver independently, though they are not required to transmit or receive packets. Clearly, this approach contributes to wasted energy. Thus, in this paper, we propose an Energy-Saving scheme that is based on downstream Packet Scheduling (ESPS) in Ethernet PON (EPON). First, we design both an algorithm and a rule for downstream packet scheduling at the inter- and intra-ONU levels, respectively, to reduce the downstream packet delay. After that, we propose a hybrid sleep mode that contains not only ONU deep sleep mode but also independent sleep modes for the transmitter and the receiver. This ensures that the energy consumed by the ONUs is minimal. To realize the hybrid sleep mode, a modified GATE control message is designed that involves 10 time points for sleep processes. In ESPS, the 10 time points are calculated according to the allocated bandwidths in both the upstream and the downstream. The simulation results show that ESPS outperforms traditional Upstream Centric Scheduling (UCS) scheme in terms of energy consumption and the average delay for both real-time and non-real-time packets downstream. The simulation results also show that the average energy consumption of each ONU in larger-sized networks is less than that in smaller-sized networks; hence, our ESPS is better suited for larger-sized networks.

  11. Demographic and Socioeconomic Factors Influencing Public Attitudes Toward a Presumed Consent System for Organ Donation Without and With a Priority Allocation Scheme

    PubMed Central

    Tumin, Makmor; Tafran, Khaled; Mutalib, Muzalwana Abdul Talib @ Abdul; Satar, NurulHuda Mohd; Said, Saad Mohd; Adnan, Wan Ahmad Hafiz Wan Md; Lu, Yong Sook

    2015-01-01

    Abstract The influence of demographic and socioeconomic factors on the public's attitude towards a presumed consent system (PCS) of organ donation was estimated in 2 scenarios: without and with a priority allocation scheme (PAS). Self-administered questionnaires were completed by 775 respondents. Using multiple logistic regressions, respondents’ objections to donating organs in both scenarios were estimated. In total, 63.9% of respondents would object to donating under a PCS, whereas 54.6% would object under a PCS with a PAS. Respondents with pretertiary education were more likely to object than were respondents with tertiary education, in both the first (adjusted odds ratio [AOR] = 1.615) and second (AOR = 1.728) scenarios. Young respondents were less likely to object than were middle-aged respondents, in both the first (AOR = 0.648) and second (AOR = 0.572) scenarios. Respondents with mid-ranged personal monthly income were more likely to object than were respondents with low income, in both the first (AOR = 1.994) and second (AOR = 1.519) scenarios. It does not seem that Malaysia is ready to implement a PCS. The educational level, age, and income of the broader public should be considered if a PCS, without or with a PAS, is planned for implementation in Malaysia. PMID:26496282

  12. Demographic and Socioeconomic Factors Influencing Public Attitudes Toward a Presumed Consent System for Organ Donation Without and With a Priority Allocation Scheme.

    PubMed

    Tumin, Makmor; Tafran, Khaled; Mutalib, Muzalwana Abdul Talib Abdul; Satar, NurulHuda Mohd; Said, Saad Mohd; Adnan, Wan Ahmad Hafiz Wan Md; Lu, Yong Sook

    2015-10-01

    The influence of demographic and socioeconomic factors on the public's attitude towards a presumed consent system (PCS) of organ donation was estimated in 2 scenarios: without and with a priority allocation scheme (PAS). Self-administered questionnaires were completed by 775 respondents. Using multiple logistic regressions, respondents' objections to donating organs in both scenarios were estimated. In total, 63.9% of respondents would object to donating under a PCS, whereas 54.6% would object under a PCS with a PAS. Respondents with pretertiary education were more likely to object than were respondents with tertiary education, in both the first (adjusted odds ratio [AOR] = 1.615) and second (AOR = 1.728) scenarios. Young respondents were less likely to object than were middle-aged respondents, in both the first (AOR = 0.648) and second (AOR = 0.572) scenarios. Respondents with mid-ranged personal monthly income were more likely to object than were respondents with low income, in both the first (AOR = 1.994) and second (AOR = 1.519) scenarios. It does not seem that Malaysia is ready to implement a PCS. The educational level, age, and income of the broader public should be considered if a PCS, without or with a PAS, is planned for implementation in Malaysia. PMID:26496282

  13. Intra-District Resource Allocation and Criteria Used for Student Based Funding in Urban School Districts

    ERIC Educational Resources Information Center

    Aloo, Peter Mangla

    2011-01-01

    Resource allocation to school sites in public school districts is inequitable. While Student Based Funding (SBF) has been implemented in several major urban school districts, there are few empirical studies about how SBF policies are derived and implemented. Current efforts to align resources with student need are hindered by a lack of systematic,…

  14. Outcome Based Budgeting: Connecting Budget Development, Allocation and Outcomes.

    ERIC Educational Resources Information Center

    Anderes, Thomas

    This plan for outcome-based budgeting (OBB) is the result of growing demands for increased fiscal accountability, measurable outcomes, strengthened assessment processes, and more meaningful performance indicators as mandated by many State and Federal legislators. OBB focuses on linking funding with outputs and outcomes. Higher education…

  15. Biometrics based authentication scheme for session initiation protocol.

    PubMed

    Xie, Qi; Tang, Zhixiong

    2016-01-01

    Many two-factor challenge-response based session initiation protocol (SIP) has been proposed, but most of them are vulnerable to smart card stolen attacks and password guessing attacks. In this paper, we propose a novel three-factor SIP authentication scheme using biometrics, password and smart card, and utilize the pi calculus-based formal verification tool ProVerif to prove that the proposed protocol achieves security and authentication. Furthermore, our protocol is highly efficient when compared to other related protocols. PMID:27462493

  16. Design and implementation of priority and time-window based traffic scheduling and routing-spectrum allocation mechanism in elastic optical networks

    NASA Astrophysics Data System (ADS)

    Wang, Honghuan; Xing, Fangyuan; Yin, Hongxi; Zhao, Nan; Lian, Bizhan

    2016-02-01

    With the explosive growth of network services, the reasonable traffic scheduling and efficient configuration of network resources have an important significance to increase the efficiency of the network. In this paper, an adaptive traffic scheduling policy based on the priority and time window is proposed and the performance of this algorithm is evaluated in terms of scheduling ratio. The routing and spectrum allocation are achieved by using the Floyd shortest path algorithm and establishing a node spectrum resource allocation model based on greedy algorithm, which is proposed by us. The fairness index is introduced to improve the capability of spectrum configuration. The results show that the designed traffic scheduling strategy can be applied to networks with multicast and broadcast functionalities, and makes them get real-time and efficient response. The scheme of node spectrum configuration improves the frequency resource utilization and gives play to the efficiency of the network.

  17. An entropy-based classification scheme of meandering rivers

    NASA Astrophysics Data System (ADS)

    Abad, J. D.; Gutierrez, R. R.

    2015-12-01

    Some researchers have highlighted the fact that most of the river classification schemes have not evolved at the same pace as river morphodynamics models have done it. The most prevailing classification scheme of meandering river was proposed by Brice (1975) and is mainly based on observational criteria. Likewise, thermodynamics principles have been applied on geomorphology over a relatively long period of time. Thus, for instance, a strong analogy between meander angle of deflection and the distribution of momentum in gas dynamics has been identified. Based on the analysis of curvature data from 16 natural meanders (which totals 52 realizations) ranging from class B to class G related to the Brice classification scheme, we propose a two-parameter meandering classification schemen, namely: [1] the yearly Shannon wavelet based negentropy gradient (ΔSWT), and [2] a quantitative continuum of the degree of confinement, which is estimated from the dimensonless Frechet distance (δF*) between the meandering centerline curvature and that of the mean center. Our results show that δF* identifies a threshold of ˜650 to discriminate freely from confined rivers; thereby, scales of the second and third degree of confinement are quantified. Likewise, the proxy parameter ΔSWT suggests that there are 4 degrees of meandering morphodynamics which lay in the intervals [10-1-100], [100-101], [101-102], and [102-103]. Our results also suggest that the lower negentropy corresponds to G1 meanders (two phase, bimodal bankfull sinuosity, equiwidth) and class B2 (single phase, wider at bends, no bars). Class G2 (two phase, bimodal bankfull sinuosity, wider at bends with point bars) and class C (single phase wider a bends, no bars) exhibit higher negentropy (single phase wider at bends width point bars). Likewise, the middle-negentropy group is comprised by both confined meanders (B1, single phase and equiwidth channel, and D, single phase, wider at bends with point bars and chutes) and

  18. An improved biometrics-based remote user authentication scheme with user anonymity.

    PubMed

    Khan, Muhammad Khurram; Kumari, Saru

    2013-01-01

    The authors review the biometrics-based user authentication scheme proposed by An in 2012. The authors show that there exist loopholes in the scheme which are detrimental for its security. Therefore the authors propose an improved scheme eradicating the flaws of An's scheme. Then a detailed security analysis of the proposed scheme is presented followed by its efficiency comparison. The proposed scheme not only withstands security problems found in An's scheme but also provides some extra features with mere addition of only two hash operations. The proposed scheme allows user to freely change his password and also provides user anonymity with untraceability. PMID:24350272

  19. Arbitrated quantum signature scheme based on reusable key

    NASA Astrophysics Data System (ADS)

    Yu, ChaoHua; Guo, GongDe; Lin, Song

    2014-11-01

    An arbitrated quantum signature scheme without using entangled states is proposed. In the scheme, by employing a classical hash function and random numbers, the secret keys of signer and receiver can be reused. It is shown that the proposed scheme is secure against several well-known attacks. Specifically, it can stand against the receiver's disavowal attack. Moreover, compared with previous relevant arbitrated quantum signature schemes, the scheme proposed has the advantage of less transmission complexity.

  20. Self-consistency based control scheme for magnetization dynamics

    SciTech Connect

    Albuquerque, G.; Miltat, J.; Thiaville, A.

    2001-06-01

    A numerical framework is presented for the solution of the Landau{endash}Lifshitz{endash}Gilbert equation of magnetization motion using a semi-implicit Crank{endash}Nicholson integration scheme. Along with the details of both space and time domain discretizations, we report on the development of a physically based self-consistency criterion that allows for a quantitative measurement of error in dynamic micromagnetic simulations. In essence, this criterion relies in recalculating from actual magnetization motion the imposed phenomenological damping constant. Test calculations were performed with special attention paid to the determination of suitable integration time steps. {copyright} 2001 American Institute of Physics.

  1. A proposed classification scheme for Ada-based software products

    NASA Technical Reports Server (NTRS)

    Cernosek, Gary J.

    1986-01-01

    As the requirements for producing software in the Ada language become a reality for projects such as the Space Station, a great amount of Ada-based program code will begin to emerge. Recognizing the potential for varying levels of quality to result in Ada programs, what is needed is a classification scheme that describes the quality of a software product whose source code exists in Ada form. A 5-level classification scheme is proposed that attempts to decompose this potentially broad spectrum of quality which Ada programs may possess. The number of classes and their corresponding names are not as important as the mere fact that there needs to be some set of criteria from which to evaluate programs existing in Ada. An exact criteria for each class is not presented, nor are any detailed suggestions of how to effectively implement this quality assessment. The idea of Ada-based software classification is introduced and a set of requirements from which to base further research and development is suggested.

  2. Trace gas monitoring with infrared laser-based detection schemes

    NASA Astrophysics Data System (ADS)

    Sigrist, M. W.; Bartlome, R.; Marinov, D.; Rey, J. M.; Vogler, D. E.; Wächter, H.

    2008-02-01

    The success of laser-based trace gas sensing techniques crucially depends on the availability and performance of tunable laser sources combined with appropriate detection schemes. Besides near-infrared diode lasers, continuously tunable midinfrared quantum cascade lasers and nonlinear optical laser sources are preferentially employed today. Detection schemes are based on sensitive absorption measurements and comprise direct absorption in multi-pass cells as well as photoacoustic and cavity ringdown techniques in various configurations. We illustrate the performance of several systems implemented in our laboratory. These include time-resolved multicomponent traffic emission measurements with a mobile CO2-laser photoacoustic system, a diode-laser based cavity ringdown device for measurements of impurities in industrial process control, isotope ratio measurements with a difference frequency (DFG) laser source combined with balanced path length detection, detection of methylamines for breath analysis with both a near-IR diode laser and a DFG source, and finally, acetone measurements with a heatable multipass cell intended for vapor phase studies on doping agents in urine samples.

  3. Multi-Agent Based Simulation of Optimal Urban Land Use Allocation in the Middle Reaches of the Yangtze River, China

    NASA Astrophysics Data System (ADS)

    Zeng, Y.; Huang, W.; Jin, W.; Li, S.

    2016-06-01

    The optimization of land-use allocation is one of important approaches to achieve regional sustainable development. This study selects Chang-Zhu-Tan agglomeration as study area and proposed a new land use optimization allocation model. Using multi-agent based simulation model, the future urban land use optimization allocation was simulated in 2020 and 2030 under three different scenarios. This kind of quantitative information about urban land use optimization allocation and urban expansions in future would be of great interest to urban planning, water and land resource management, and climate change research.

  4. Novel schemes for measurement-based quantum computation.

    PubMed

    Gross, D; Eisert, J

    2007-06-01

    We establish a framework which allows one to construct novel schemes for measurement-based quantum computation. The technique develops tools from many-body physics-based on finitely correlated or projected entangled pair states-to go beyond the cluster-state based one-way computer. We identify resource states radically different from the cluster state, in that they exhibit nonvanishing correlations, can be prepared using nonmaximally entangling gates, or have very different local entanglement properties. In the computational models, randomness is compensated in a different manner. It is shown that there exist resource states which are locally arbitrarily close to a pure state. We comment on the possibility of tailoring computational models to specific physical systems. PMID:17677826

  5. Malicious attacks on media authentication schemes based on invertible watermarks

    NASA Astrophysics Data System (ADS)

    Katzenbeisser, Stefan; Dittmann, Jana

    2004-06-01

    The increasing availability and distribution of multimedia technology has made the manipulation of digital images, videos or audio files easy. While this enables numerous new applications, a certain loss of trust in digital media can be observed. In general, there is no guarantee that a digital image "does not lie", i.e., that the image content was not altered. To counteract this risk, fragile watermarks were proposed to protect the integrity of digital multimedia objects. In high security applications, it is necessary to be able to reconstruct the original object out of the watermarked version. This can be achieved by the use of invertible watermarks. While traditional watermarking schemes introduce some small non-invertible distortion in the digital content, invertible watermarks can be completely removed from a watermarked work. In the past, the security of proposed image authentication schemes based on invertible watermarks was only analyzed using ad-hoc methods and neglected the possibility of malicious attacks, which aim at engineering a fake mark so that the attacked object appears to be genuine. In this paper, we characterize and analyze possible malicious attacks against watermark-based image authentication systems and explore the theoretical limits of previous constructions with respect to their security.

  6. A 'resource allocator' for transcription based on a highly fragmented T7 RNA polymerase.

    PubMed

    Segall-Shapiro, Thomas H; Meyer, Adam J; Ellington, Andrew D; Sontag, Eduardo D; Voigt, Christopher A

    2014-01-01

    Synthetic genetic systems share resources with the host, including machinery for transcription and translation. Phage RNA polymerases (RNAPs) decouple transcription from the host and generate high expression. However, they can exhibit toxicity and lack accessory proteins (σ factors and activators) that enable switching between different promoters and modulation of activity. Here, we show that T7 RNAP (883 amino acids) can be divided into four fragments that have to be co-expressed to function. The DNA-binding loop is encoded in a C-terminal 285-aa 'σ fragment', and fragments with different specificity can direct the remaining 601-aa 'core fragment' to different promoters. Using these parts, we have built a resource allocator that sets the core fragment concentration, which is then shared by multiple σ fragments. Adjusting the concentration of the core fragment sets the maximum transcriptional capacity available to a synthetic system. Further, positive and negative regulation is implemented using a 67-aa N-terminal 'α fragment' and a null (inactivated) σ fragment, respectively. The α fragment can be fused to recombinant proteins to make promoters responsive to their levels. These parts provide a toolbox to allocate transcriptional resources via different schemes, which we demonstrate by building a system which adjusts promoter activity to compensate for the difference in copy number of two plasmids. PMID:25080493

  7. Comprehensive reliability allocation method for CNC lathes based on cubic transformed functions of failure mode and effects analysis

    NASA Astrophysics Data System (ADS)

    Yang, Zhou; Zhu, Yunpeng; Ren, Hongrui; Zhang, Yimin

    2015-03-01

    Reliability allocation of computerized numerical controlled(CNC) lathes is very important in industry. Traditional allocation methods only focus on high-failure rate components rather than moderate failure rate components, which is not applicable in some conditions. Aiming at solving the problem of CNC lathes reliability allocating, a comprehensive reliability allocation method based on cubic transformed functions of failure modes and effects analysis(FMEA) is presented. Firstly, conventional reliability allocation methods are introduced. Then the limitations of direct combination of comprehensive allocation method with the exponential transformed FMEA method are investigated. Subsequently, a cubic transformed function is established in order to overcome these limitations. Properties of the new transformed functions are discussed by considering the failure severity and the failure occurrence. Designers can choose appropriate transform amplitudes according to their requirements. Finally, a CNC lathe and a spindle system are used as an example to verify the new allocation method. Seven criteria are considered to compare the results of the new method with traditional methods. The allocation results indicate that the new method is more flexible than traditional methods. By employing the new cubic transformed function, the method covers a wider range of problems in CNC reliability allocation without losing the advantages of traditional methods.

  8. Knowledge-based load leveling and task allocation in human-machine systems

    NASA Technical Reports Server (NTRS)

    Chignell, M. H.; Hancock, P. A.

    1986-01-01

    Conventional human-machine systems use task allocation policies which are based on the premise of a flexible human operator. This individual is most often required to compensate for and augment the capabilities of the machine. The development of artificial intelligence and improved technologies have allowed for a wider range of task allocation strategies. In response to these issues a Knowledge Based Adaptive Mechanism (KBAM) is proposed for assigning tasks to human and machine in real time, using a load leveling policy. This mechanism employs an online workload assessment and compensation system which is responsive to variations in load through an intelligent interface. This interface consists of a loading strategy reasoner which has access to information about the current status of the human-machine system as well as a database of admissible human/machine loading strategies. Difficulties standing in the way of successful implementation of the load leveling strategy are examined.

  9. A group signature scheme based on quantum teleportation

    NASA Astrophysics Data System (ADS)

    Wen, Xiaojun; Tian, Yuan; Ji, Liping; Niu, Xiamu

    2010-05-01

    In this paper, we present a group signature scheme using quantum teleportation. Different from classical group signature and current quantum signature schemes, which could only deliver either group signature or unconditional security, our scheme guarantees both by adopting quantum key preparation, quantum encryption algorithm and quantum teleportation. Security analysis proved that our scheme has the characteristics of group signature, non-counterfeit, non-disavowal, blindness and traceability. Our quantum group signature scheme has a foreseeable application in the e-payment system, e-government, e-business, etc.

  10. A Bayesian formulation for auction-based task allocation in heterogeneous multi-agent teams

    NASA Astrophysics Data System (ADS)

    Pippin, Charles E.; Christensen, Henrik

    2011-06-01

    In distributed, heterogeneous, multi-agent teams, agents may have different capabilities and types of sensors. Agents in dynamic environments will need to cooperate in real-time to perform tasks with minimal costs. Some example scenarios include dynamic allocation of UAV and UGV robot teams to possible hurricane survivor locations, search and rescue and target detection. Auction based algorithms scale well because agents generally only need to communicate bid information. In addition, the agents are able to perform their computations in parallel and can operate on local information. Furthermore, it is easy to integrate humans and other vehicle types and sensor combinations into an auction framework. However, standard auction mechanisms do not explicitly consider sensors with varying reliability. The agents sensor qualities should be explicitly accounted. Consider a scenario with multiple agents, each carrying a single sensor. The tasks in this case are to simply visit a location and detect a target. The sensors are of varying quality, with some having a higher probability of target detection. The agents themselves may have different capabilities, as well. The agents use knowledge of their environment to submit cost-based bids for performing each task and an auction is used to perform the task allocation. This paper discusses techniques for including a Bayesian formulation of target detection likelihood into this auction based framework for performing task allocation across multi-agent heterogeneous teams. Analysis and results of experiments with multiple air systems performing distributed target detection are also included.

  11. Allocation Variable-Based Probabilistic Algorithm to Deal with Label Switching Problem in Bayesian Mixture Models

    PubMed Central

    Pan, Jia-Chiun; Liu, Chih-Min; Hwu, Hai-Gwo; Huang, Guan-Hua

    2015-01-01

    The label switching problem occurs as a result of the nonidentifiability of posterior distribution over various permutations of component labels when using Bayesian approach to estimate parameters in mixture models. In the cases where the number of components is fixed and known, we propose a relabelling algorithm, an allocation variable-based (denoted by AVP) probabilistic relabelling approach, to deal with label switching problem. We establish a model for the posterior distribution of allocation variables with label switching phenomenon. The AVP algorithm stochastically relabel the posterior samples according to the posterior probabilities of the established model. Some existing deterministic and other probabilistic algorithms are compared with AVP algorithm in simulation studies, and the success of the proposed approach is demonstrated in simulation studies and a real dataset. PMID:26458185

  12. Optimization algorithm based characterization scheme for tunable semiconductor lasers.

    PubMed

    Chen, Quanan; Liu, Gonghai; Lu, Qiaoyin; Guo, Weihua

    2016-09-01

    In this paper, an optimization algorithm based characterization scheme for tunable semiconductor lasers is proposed and demonstrated. In the process of optimization, the ratio between the power of the desired frequency and the power except of the desired frequency is used as the figure of merit, which approximately represents the side-mode suppression ratio. In practice, we use tunable optical band-pass and band-stop filters to obtain the power of the desired frequency and the power except of the desired frequency separately. With the assistance of optimization algorithms, such as the particle swarm optimization (PSO) algorithm, we can get stable operation conditions for tunable lasers at designated frequencies directly and efficiently. PMID:27607701

  13. MIMO transmit scheme based on morphological perceptron with competitive learning.

    PubMed

    Valente, Raul Ambrozio; Abrão, Taufik

    2016-08-01

    This paper proposes a new multi-input multi-output (MIMO) transmit scheme aided by artificial neural network (ANN). The morphological perceptron with competitive learning (MP/CL) concept is deployed as a decision rule in the MIMO detection stage. The proposed MIMO transmission scheme is able to achieve double spectral efficiency; hence, in each time-slot the receiver decodes two symbols at a time instead one as Alamouti scheme. Other advantage of the proposed transmit scheme with MP/CL-aided detector is its polynomial complexity according to modulation order, while it becomes linear when the data stream length is greater than modulation order. The performance of the proposed scheme is compared to the traditional MIMO schemes, namely Alamouti scheme and maximum-likelihood MIMO (ML-MIMO) detector. Also, the proposed scheme is evaluated in a scenario with variable channel information along the frame. Numerical results have shown that the diversity gain under space-time coding Alamouti scheme is partially lost, which slightly reduces the bit-error rate (BER) performance of the proposed MP/CL-NN MIMO scheme. PMID:27135805

  14. Cryptanalysis and Improvement of a Biometric-Based Multi-Server Authentication and Key Agreement Scheme

    PubMed Central

    Wang, Chengqi; Zhang, Xiao; Zheng, Zhiming

    2016-01-01

    With the security requirements of networks, biometrics authenticated schemes which are applied in the multi-server environment come to be more crucial and widely deployed. In this paper, we propose a novel biometric-based multi-server authentication and key agreement scheme which is based on the cryptanalysis of Mishra et al.’s scheme. The informal and formal security analysis of our scheme are given, which demonstrate that our scheme satisfies the desirable security requirements. The presented scheme provides a variety of significant functionalities, in which some features are not considered in the most of existing authentication schemes, such as, user revocation or re-registration and biometric information protection. Compared with several related schemes, our scheme has more secure properties and lower computation cost. It is obviously more appropriate for practical applications in the remote distributed networks. PMID:26866606

  15. A secure smart-card based authentication and key agreement scheme for telecare medicine information systems.

    PubMed

    Lee, Tian-Fu; Liu, Chuan-Ming

    2013-06-01

    A smart-card based authentication scheme for telecare medicine information systems enables patients, doctors, nurses, health visitors and the medicine information systems to establish a secure communication platform through public networks. Zhu recently presented an improved authentication scheme in order to solve the weakness of the authentication scheme of Wei et al., where the off-line password guessing attacks cannot be resisted. This investigation indicates that the improved scheme of Zhu has some faults such that the authentication scheme cannot execute correctly and is vulnerable to the attack of parallel sessions. Additionally, an enhanced authentication scheme based on the scheme of Zhu is proposed. The enhanced scheme not only avoids the weakness in the original scheme, but also provides users' anonymity and authenticated key agreements for secure data communications. PMID:23494392

  16. Improved dynamic ID-based authentication scheme for telecare medical information systems.

    PubMed

    Cao, Tianjie; Zhai, Jingxuan

    2013-04-01

    In order to protect users' identity privacy, Chen et al. proposed an efficient dynamic ID-based authentication scheme for telecare medical information systems. However, Chen et al.'s scheme has some weaknesses. In Chen et al.'s scheme, an attacker can track a user by a linkability attack or an off-line identity guessing attack. Chen et al.'s scheme is also vulnerable to an off-line password guessing attack and an undetectable on-line password guessing attack when user's smart card is stolen. In server side, Chen et al.'s scheme needs large computational load to authentication a legal user or reject an illegal user. To remedy the weaknesses in Chen et al.'s scheme, we propose an improved smart card based password authentication scheme. Our analysis shows that the improved scheme can overcome the weaknesses in Chen et al.'s scheme. PMID:23345091

  17. Cryptanalysis and Improvement of a Biometric-Based Multi-Server Authentication and Key Agreement Scheme.

    PubMed

    Wang, Chengqi; Zhang, Xiao; Zheng, Zhiming

    2016-01-01

    With the security requirements of networks, biometrics authenticated schemes which are applied in the multi-server environment come to be more crucial and widely deployed. In this paper, we propose a novel biometric-based multi-server authentication and key agreement scheme which is based on the cryptanalysis of Mishra et al.'s scheme. The informal and formal security analysis of our scheme are given, which demonstrate that our scheme satisfies the desirable security requirements. The presented scheme provides a variety of significant functionalities, in which some features are not considered in the most of existing authentication schemes, such as, user revocation or re-registration and biometric information protection. Compared with several related schemes, our scheme has more secure properties and lower computation cost. It is obviously more appropriate for practical applications in the remote distributed networks. PMID:26866606

  18. Equity in health care in Namibia: developing a needs-based resource allocation formula using principal components analysis

    PubMed Central

    Zere, Eyob; Mandlhate, Custodia; Mbeeli, Thomas; Shangula, Kalumbi; Mutirua, Kauto; Kapenambili, William

    2007-01-01

    Background The pace of redressing inequities in the distribution of scarce health care resources in Namibia has been slow. This is due primarily to adherence to the historical incrementalist type of budgeting that has been used to allocate resources. Those regions with high levels of deprivation and relatively greater need for health care resources have been getting less than their fair share. To rectify this situation, which was inherited from the apartheid system, there is a need to develop a needs-based resource allocation mechanism. Methods Principal components analysis was employed to compute asset indices from asset based and health-related variables, using data from the Namibia demographic and health survey of 2000. The asset indices then formed the basis of proposals for regional weights for establishing a needs-based resource allocation formula. Results Comparing the current allocations of public sector health car resources with estimates using a needs based formula showed that regions with higher levels of need currently receive fewer resources than do regions with lower need. Conclusion To address the prevailing inequities in resource allocation, the Ministry of Health and Social Services should abandon the historical incrementalist method of budgeting/resource allocation and adopt a more appropriate allocation mechanism that incorporates measures of need for health care. PMID:17391533

  19. On the fly all-optical packet switching based on hybrid WDM/OCDMA labeling scheme

    NASA Astrophysics Data System (ADS)

    Brahmi, Houssem; Giannoulis, Giannis; Menif, Mourad; Katopodis, Vasilis; Kalavrouziotis, Dimitrios; Kouloumentas, Christos; Groumas, Panos; Kanakis, Giannis; Stamatiadis, Christos; Avramopoulos, Hercules; Erasme, Didier

    2014-02-01

    We introduce a novel design of an all-optical packet routing node that allows for the selection and forwarding of optical packets based on the routing information contained in hybrid wavelength division multiplexing/optical code division multiple access (WDM/OCDMA) labels. A stripping paradigm of optical code-label is adopted. The router is built around an optical-code gate that consists in an optical flip-flop controlled by two fiber Bragg grating correlators and is combined with a Mach-Zehnder interferometer (MZI)-based forwarding gate. We experimentally verify the proof-of-principle operation of the proposed self-routing node under NRZ and OCDMA packet traffic conditions. The successful switching of elastic NRZ payload at 40 Gb/s controlled by DS-OCDMA coded labels and the forwarding operation of encoded data using EQC codes are presented. Proper auto-correlation functions are obtained with higher than 8.1 dB contrast ratio, suitable to efficiently trigger the latching device with a contrast ratio of 11.6 dB and switching times below 3.8 ns. Error-free operation is achieved with 1.5 dB penalty for 40 Gb/s NRZ data and with 2.1 dB penalty for DS-OCDMA packets. The scheme can further be applied to large-scale optical packet switching networks by exploiting efficient optical coders allocated at different WDM channels.

  20. An Anonymous Voting Scheme based on Confirmation Numbers

    NASA Astrophysics Data System (ADS)

    Alam, Kazi Md. Rokibul; Tamura, Shinsuke; Taniguchi, Shuji; Yanase, Tatsuro

    This paper proposes a new electronic voting (e-voting) scheme that fulfills all the security requirements of e-voting i.e. privacy, accuracy, universal verifiability, fairness, receipt-freeness, incoercibility, dispute-freeness, robustness, practicality and scalability; usually some of which are found to be traded. When compared with other existing schemes, this scheme requires much more simple computations and weaker assumptions about trustworthiness of individual election authorities. The key mechanism is the one that uses confirmation numbers involved in individual votes to make votes verifiable while disabling all entities including voters themselves to know the linkages between voters and their votes. Many existing e-voting schemes extensively deploy zero-knowledge proof (ZKP) to achieve verifiability. However, ZKP is expensive and complicated. The confirmation numbers attain the verifiability requirement in a much more simple and intuitive way, then the scheme becomes scalable and practical.

  1. A Location-Based Duplex Scheme for Cost Effective Rural Broadband Connectivity Using IEEE 802.22 Cognitive Radio Based Wireless Regional Area Networks

    NASA Astrophysics Data System (ADS)

    Kalidoss, R.; Bhagyaveni, M. A.; Vishvaksenan, K. S.

    2014-08-01

    The search for a method of utilizing the scarce spectrum in an efficient manner is an active area of research in both academic and industrial communities. IEEE 802.22 is a standard for wireless regional area network (WRAN) based on cognitive radio (CR) that operates over underutilized portions of TV bands (54-862 MHz). Time division duplex (TDD)-based WRAN cells have such advantages as dynamic traffic allocation, traffic asymmetry to users and ease of spectrum allocation. However, these cells suffer from severe cross time slot (CTS) interference when the frames of the cells are not synchronized with adjacent WRAN cells. In this paper, we evaluate the location-based duplex (LBD) scheme for eliminating the CTS interference. The proposed LBD system is much more flexible and efficient in providing asymmetric data service and eliminating CTS interference by exploiting the advantages of both TDD and frequency division duplex (FDD) schemes. We also compare the performance of LBD systems with virtual cell concepts. Furthermore, our simulation results reveal that LBD-based systems outperform the virtual cell approach in terms of the low signal-to-interference (SIR) ratio requirement by mitigating the effects of CTS.

  2. A Quantum Multi-proxy Blind Signature Scheme Based on Genuine Four-Qubit Entangled State

    NASA Astrophysics Data System (ADS)

    Tian, Juan-Hong; Zhang, Jian-Zhong; Li, Yan-Ping

    2016-02-01

    In this paper, we propose a multi-proxy blind signature scheme based on controlled teleportation. Genuine four-qubit entangled state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to implement delegation, signature and verification. The security analysis shows the scheme satisfies the security features of multi-proxy signature, unforgeability, undeniability, blindness and unconditional security.

  3. Fairing geometric modeling based on 4-point interpolatory subdivision scheme

    NASA Astrophysics Data System (ADS)

    Luo, Xiaonan; Liu, Ning; Gao, Chengying

    2004-02-01

    A 4-point interpolatory subdivision scheme with a tension parameter is analyzed, and the local property of 4-point interpolatory subdivision scheme and a kind of G1-continuity sufficient condition between surfaces as well as between curves are discussed. An efficient method of generating natural boundary points of 4-point interpolatory curve is presented, as well as a surface modeling method with the entire fairing property by combining energy optimization with subdivision scheme. The method has been applied in modeling 3D virtual garment surface.

  4. Asymmetric Programming: A Highly Reliable Metadata Allocation Strategy for MLC NAND Flash Memory-Based Sensor Systems

    PubMed Central

    Huang, Min; Liu, Zhaoqing; Qiao, Liyan

    2014-01-01

    While the NAND flash memory is widely used as the storage medium in modern sensor systems, the aggressive shrinking of process geometry and an increase in the number of bits stored in each memory cell will inevitably degrade the reliability of NAND flash memory. In particular, it's critical to enhance metadata reliability, which occupies only a small portion of the storage space, but maintains the critical information of the file system and the address translations of the storage system. Metadata damage will cause the system to crash or a large amount of data to be lost. This paper presents Asymmetric Programming, a highly reliable metadata allocation strategy for MLC NAND flash memory storage systems. Our technique exploits for the first time the property of the multi-page architecture of MLC NAND flash memory to improve the reliability of metadata. The basic idea is to keep metadata in most significant bit (MSB) pages which are more reliable than least significant bit (LSB) pages. Thus, we can achieve relatively low bit error rates for metadata. Based on this idea, we propose two strategies to optimize address mapping and garbage collection. We have implemented Asymmetric Programming on a real hardware platform. The experimental results show that Asymmetric Programming can achieve a reduction in the number of page errors of up to 99.05% with the baseline error correction scheme. PMID:25310473

  5. Total waste-load control and allocation based on input-output analysis for Shenzhen, south China.

    PubMed

    Ni, J R; Zhong, D S; Huang, Y F; Wang, H

    2001-01-01

    The general objective for this paper is to reveal the dynamic relationships between the rapid economic development, water pollution and the subsequent waste-load allocation in different economic sectors through a case-study in Shenzhen City, South China. Two-objective analysis model was employed based on the input-output table for Shenzhen with the full consideration of various constraints in local area. The improved Tchebycheff procedure was used for obtaining the solutions. The predictions were made on economic development and pollutants from wastewater in different sectors and different planning years. The present study allows for the consideration of the economic structural adjustment. It is found that the current situation of economic structure is generally good and is subject to further adjustment in Shenzhen, although it has undergone the rapid development in the past 18 years. When the maximum Gross Domestic Production and the minimum Chemical Oxygen Demand are chosen as the two objectives subject to other constraints, the harmonized results indicated a scheme that claims substantial reduction of polluting effluences in Shenzhen while closely keeping the economic growth rate as planned. PMID:11381457

  6. A Rhythm-Based Authentication Scheme for Smart Media Devices

    PubMed Central

    Lee, Jae Dong; Park, Jong Hyuk

    2014-01-01

    In recent years, ubiquitous computing has been rapidly emerged in our lives and extensive studies have been conducted in a variety of areas related to smart devices, such as tablets, smartphones, smart TVs, smart refrigerators, and smart media devices, as a measure for realizing the ubiquitous computing. In particular, smartphones have significantly evolved from the traditional feature phones. Increasingly higher-end smartphone models that can perform a range of functions are now available. Smart devices have become widely popular since they provide high efficiency and great convenience for not only private daily activities but also business endeavors. Rapid advancements have been achieved in smart device technologies to improve the end users' convenience. Consequently, many people increasingly rely on smart devices to store their valuable and important data. With this increasing dependence, an important aspect that must be addressed is security issues. Leaking of private information or sensitive business data due to loss or theft of smart devices could result in exorbitant damage. To mitigate these security threats, basic embedded locking features are provided in smart devices. However, these locking features are vulnerable. In this paper, an original security-locking scheme using a rhythm-based locking system (RLS) is proposed to overcome the existing security problems of smart devices. RLS is a user-authenticated system that addresses vulnerability issues in the existing locking features and provides secure confidentiality in addition to convenience. PMID:25110743

  7. A Malware Detection Scheme Based on Mining Format Information

    PubMed Central

    Bai, Jinrong; Wang, Junfeng; Zou, Guozhong

    2014-01-01

    Malware has become one of the most serious threats to computer information system and the current malware detection technology still has very significant limitations. In this paper, we proposed a malware detection approach by mining format information of PE (portable executable) files. Based on in-depth analysis of the static format information of the PE files, we extracted 197 features from format information of PE files and applied feature selection methods to reduce the dimensionality of the features and achieve acceptable high performance. When the selected features were trained using classification algorithms, the results of our experiments indicate that the accuracy of the top classification algorithm is 99.1% and the value of the AUC is 0.998. We designed three experiments to evaluate the performance of our detection scheme and the ability of detecting unknown and new malware. Although the experimental results of identifying new malware are not perfect, our method is still able to identify 97.6% of new malware with 1.3% false positive rates. PMID:24991639

  8. A malware detection scheme based on mining format information.

    PubMed

    Bai, Jinrong; Wang, Junfeng; Zou, Guozhong

    2014-01-01

    Malware has become one of the most serious threats to computer information system and the current malware detection technology still has very significant limitations. In this paper, we proposed a malware detection approach by mining format information of PE (portable executable) files. Based on in-depth analysis of the static format information of the PE files, we extracted 197 features from format information of PE files and applied feature selection methods to reduce the dimensionality of the features and achieve acceptable high performance. When the selected features were trained using classification algorithms, the results of our experiments indicate that the accuracy of the top classification algorithm is 99.1% and the value of the AUC is 0.998. We designed three experiments to evaluate the performance of our detection scheme and the ability of detecting unknown and new malware. Although the experimental results of identifying new malware are not perfect, our method is still able to identify 97.6% of new malware with 1.3% false positive rates. PMID:24991639

  9. A LAGUERRE VORONOI BASED SCHEME FOR MESHING PARTICLE SYSTEMS

    PubMed Central

    Bajaj, Chandrajit

    2009-01-01

    We present Laguerre Voronoi based subdivision algorithms for the quadrilateral and hexahedral meshing of particle systems within a bounded region in two and three dimensions, respectively. Particles are smooth functions over circular or spherical domains. The algorithm first breaks the bounded region containing the particles into Voronoi cells that are then subsequently decomposed into an initial quadrilateral or an initial hexahedral scaffold conforming to individual particles. The scaffolds are subsequently refined via applications of recursive subdivision (splitting and averaging rules). Our choice of averaging rules yield a particle conforming quadrilateral/hexahedral mesh, of good quality, along with being smooth and differentiable in the limit. Extensions of the basic scheme to dynamic re-meshing in the case of addition, deletion, and moving particles are also discussed. Motivating applications of the use of these static and dynamic meshes for particle systems include the mechanics of epoxy/glass composite materials, bio-molecular force field calculations, and gas hydrodynamics simulations in cosmology PMID:20454544

  10. A rhythm-based authentication scheme for smart media devices.

    PubMed

    Lee, Jae Dong; Jeong, Young-Sik; Park, Jong Hyuk

    2014-01-01

    In recent years, ubiquitous computing has been rapidly emerged in our lives and extensive studies have been conducted in a variety of areas related to smart devices, such as tablets, smartphones, smart TVs, smart refrigerators, and smart media devices, as a measure for realizing the ubiquitous computing. In particular, smartphones have significantly evolved from the traditional feature phones. Increasingly higher-end smartphone models that can perform a range of functions are now available. Smart devices have become widely popular since they provide high efficiency and great convenience for not only private daily activities but also business endeavors. Rapid advancements have been achieved in smart device technologies to improve the end users' convenience. Consequently, many people increasingly rely on smart devices to store their valuable and important data. With this increasing dependence, an important aspect that must be addressed is security issues. Leaking of private information or sensitive business data due to loss or theft of smart devices could result in exorbitant damage. To mitigate these security threats, basic embedded locking features are provided in smart devices. However, these locking features are vulnerable. In this paper, an original security-locking scheme using a rhythm-based locking system (RLS) is proposed to overcome the existing security problems of smart devices. RLS is a user-authenticated system that addresses vulnerability issues in the existing locking features and provides secure confidentiality in addition to convenience. PMID:25110743

  11. Multiparty quantum secret sharing scheme based on the phase shift operations

    NASA Astrophysics Data System (ADS)

    Du, Yu-tao; Bao, Wan-su

    2013-11-01

    Based on a kind of multiparty quantum secret sharing schemes with Bell states, we propose a novel collective attack strategy in this paper. In our strategy, the group of in-attackers can obtain the entire secret information without introducing any error. More interestingly, a new multiparty quantum secret sharing scheme is proposed based on the 3-element phase shift operations. The scheme can resist not only the existing attacks, but also the cheating attack from the dishonest agent. Meanwhile, the scheme improves the efficiency of scheme by reducing the number of the eavesdropping detections and the computation complexity.

  12. Experimental quantum cryptography scheme based on orthogonal states: preliminary results

    NASA Astrophysics Data System (ADS)

    Avella, Alessio; Brida, Giorgio; Degiovanni, Ivo P.; Genovese, Marco; Gramegna, Marco; Traina, Paolo

    2010-04-01

    Since, in general, non-orthogonal states cannot be cloned, any eavesdropping attempt in a Quantum Communication scheme using non-orthogonal states as carriers of information introduces some errors in the transmission, leading to the possibility of detecting the spy. Usually, orthogonal states are not used in Quantum Cryptography schemes since they can be faithfully cloned without altering the transmitted data. Nevertheless, L. Goldberg and L. Vaidman [Phys. Rev. Lett. 75 (7), pp. 12391243, 1995] proposed a protocol in which, even if the data exchange is realized using two orthogonal states, any attempt to eavesdrop is detectable by the legal users. In this scheme the orthogonal states are superpositions of two localized wave packets which travel along separate channels, i.e. two different paths inside a balanced Mach-Zehnder interferometer. Here we present an experiment realizing this scheme.

  13. Experimental quantum-cryptography scheme based on orthogonal states

    NASA Astrophysics Data System (ADS)

    Avella, Alessio; Brida, Giorgio; Degiovanni, Ivo Pietro; Genovese, Marco; Gramegna, Marco; Traina, Paolo

    2010-12-01

    Since, in general, nonorthogonal states cannot be cloned, any eavesdropping attempt in a quantum-communication scheme using nonorthogonal states as carriers of information introduces some errors in the transmission, leading to the possibility of detecting the spy. Usually, orthogonal states are not used in quantum-cryptography schemes since they can be faithfully cloned without altering the transmitted data. Nevertheless, L. Goldberg and L. Vaidman [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.75.1239 75, 1239 (1995)] proposed a protocol in which, even if the data exchange is realized using two orthogonal states, any attempt to eavesdrop is detectable by the legal users. In this scheme the orthogonal states are superpositions of two localized wave packets traveling along separate channels. Here we present an experiment realizing this scheme.

  14. Experimental quantum-cryptography scheme based on orthogonal states

    SciTech Connect

    Avella, Alessio; Brida, Giorgio; Degiovanni, Ivo Pietro; Genovese, Marco; Gramegna, Marco; Traina, Paolo

    2010-12-15

    Since, in general, nonorthogonal states cannot be cloned, any eavesdropping attempt in a quantum-communication scheme using nonorthogonal states as carriers of information introduces some errors in the transmission, leading to the possibility of detecting the spy. Usually, orthogonal states are not used in quantum-cryptography schemes since they can be faithfully cloned without altering the transmitted data. Nevertheless, L. Goldberg and L. Vaidman [Phys. Rev. Lett. 75, 1239 (1995)] proposed a protocol in which, even if the data exchange is realized using two orthogonal states, any attempt to eavesdrop is detectable by the legal users. In this scheme the orthogonal states are superpositions of two localized wave packets traveling along separate channels. Here we present an experiment realizing this scheme.

  15. Arbitrated quantum signature scheme based on cluster states

    NASA Astrophysics Data System (ADS)

    Yang, Yu-Guang; Lei, He; Liu, Zhi-Chao; Zhou, Yi-Hua; Shi, Wei-Min

    2016-03-01

    Cluster states can be exploited for some tasks such as topological one-way computation, quantum error correction, teleportation and dense coding. In this paper, we investigate and propose an arbitrated quantum signature scheme with cluster states. The cluster states are used for quantum key distribution and quantum signature. The proposed scheme can achieve an efficiency of 100 %. Finally, we also discuss its security against various attacks.

  16. Arbitrated quantum signature scheme based on cluster states

    NASA Astrophysics Data System (ADS)

    Yang, Yu-Guang; Lei, He; Liu, Zhi-Chao; Zhou, Yi-Hua; Shi, Wei-Min

    2016-06-01

    Cluster states can be exploited for some tasks such as topological one-way computation, quantum error correction, teleportation and dense coding. In this paper, we investigate and propose an arbitrated quantum signature scheme with cluster states. The cluster states are used for quantum key distribution and quantum signature. The proposed scheme can achieve an efficiency of 100 %. Finally, we also discuss its security against various attacks.

  17. Outcome based state budget allocation for diabetes prevention programs using multi-criteria optimization with robust weights.

    PubMed

    Mehrotra, Sanjay; Kim, Kibaek

    2011-12-01

    We consider the problem of outcomes based budget allocations to chronic disease prevention programs across the United States (US) to achieve greater geographical healthcare equity. We use Diabetes Prevention and Control Programs (DPCP) by the Center for Disease Control and Prevention (CDC) as an example. We present a multi-criteria robust weighted sum model for such multi-criteria decision making in a group decision setting. The principal component analysis and an inverse linear programming techniques are presented and used to study the actual 2009 budget allocation by CDC. Our results show that the CDC budget allocation process for the DPCPs is not likely model based. In our empirical study, the relative weights for different prevalence and comorbidity factors and the corresponding budgets obtained under different weight regions are discussed. Parametric analysis suggests that money should be allocated to states to promote diabetes education and to increase patient-healthcare provider interactions to reduce disparity across the US. PMID:21674143

  18. XFEM schemes for level set based structural optimization

    NASA Astrophysics Data System (ADS)

    Li, Li; Wang, Michael Yu; Wei, Peng

    2012-12-01

    In this paper, some elegant extended finite element method (XFEM) schemes for level set method structural optimization are proposed. Firstly, two-dimension (2D) and three-dimension (3D) XFEM schemes with partition integral method are developed and numerical examples are employed to evaluate their accuracy, which indicate that an accurate analysis result can be obtained on the structural boundary. Furthermore, the methods for improving the computational accuracy and efficiency of XFEM are studied, which include the XFEM integral scheme without quadrature sub-cells and higher order element XFEM scheme. Numerical examples show that the XFEM scheme without quadrature sub-cells can yield similar accuracy of structural analysis while prominently reducing the time cost and that higher order XFEM elements can improve the computational accuracy of structural analysis in the boundary elements, but the time cost is increasing. Therefore, the balance of time cost between FE system scale and the order of element needs to be discussed. Finally, the reliability and advantages of the proposed XFEM schemes are illustrated with several 2D and 3D mean compliance minimization examples that are widely used in the recent literature of structural topology optimization. All numerical results demonstrate that the proposed XFEM is a promising structural analysis approach for structural optimization with the level set method.

  19. 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

  20. An Identity-Based (IDB) Broadcast Encryption Scheme with Personalized Messages (BEPM)

    PubMed Central

    Xu, Ke; Liao, Yongjian; Qiao, Li

    2015-01-01

    A broadcast encryption scheme with personalized messages (BEPM) is a scheme in which a broadcaster transmits not only encrypted broadcast messages to a subset of recipients but also encrypted personalized messages to each user individually. Several broadcast encryption (BE) schemes allow a broadcaster encrypts a message for a subset S of recipients with public keys and any user in S can decrypt the message with his/her private key. However, these BE schemes can not provide an efficient way to transmit encrypted personalized messages to each user individually. In this paper, we propose a broadcast encryption scheme with a transmission of personalized messages. Besides, the scheme is based on multilinear maps ensure constant ciphertext size and private key size of each user and the scheme can achieve statically security. More realistically, the scheme can be applied to the Conditional Access System (CAS) of pay television (pay-TV) efficiently and safely. PMID:26629817

  1. A dynamic identity based authentication scheme using chaotic maps for telecare medicine information systems.

    PubMed

    Wang, Zhiheng; Huo, Zhanqiang; Shi, Wenbo

    2015-01-01

    With rapid development of computer technology and wide use of mobile devices, the telecare medicine information system has become universal in the field of medical care. To protect patients' privacy and medial data's security, many authentication schemes for the telecare medicine information system have been proposed. Due to its better performance, chaotic maps have been used in the design of authentication schemes for the telecare medicine information system. However, most of them cannot provide user's anonymity. Recently, Lin proposed a dynamic identity based authentication scheme using chaotic maps for the telecare medicine information system and claimed that their scheme was secure against existential active attacks. In this paper, we will demonstrate that their scheme cannot provide user anonymity and is vulnerable to the impersonation attack. Further, we propose an improved scheme to fix security flaws in Lin's scheme and demonstrate the proposed scheme could withstand various attacks. PMID:25486894

  2. An Identity-Based (IDB) Broadcast Encryption Scheme with Personalized Messages (BEPM).

    PubMed

    Xu, Ke; Liao, Yongjian; Qiao, Li; Liu, Zhangyun; Yang, Xiaowei

    2015-01-01

    A broadcast encryption scheme with personalized messages (BEPM) is a scheme in which a broadcaster transmits not only encrypted broadcast messages to a subset of recipients but also encrypted personalized messages to each user individually. Several broadcast encryption (BE) schemes allow a broadcaster encrypts a message for a subset S of recipients with public keys and any user in S can decrypt the message with his/her private key. However, these BE schemes can not provide an efficient way to transmit encrypted personalized messages to each user individually. In this paper, we propose a broadcast encryption scheme with a transmission of personalized messages. Besides, the scheme is based on multilinear maps ensure constant ciphertext size and private key size of each user and the scheme can achieve statically security. More realistically, the scheme can be applied to the Conditional Access System (CAS) of pay television (pay-TV) efficiently and safely. PMID:26629817

  3. Index-based reactive power compensation scheme for voltage regulation

    NASA Astrophysics Data System (ADS)

    Dike, Damian Obioma

    2008-10-01

    Increasing demand for electrical power arising from deregulation and the restrictions posed to the construction of new transmission lines by environment, socioeconomic, and political issues had led to higher grid loading. Consequently, voltage instability has become a major concern, and reactive power support is vital to enhance transmission grid performance. Improved reactive power support to distressed grid is possible through the application of relatively unfamiliar emerging technologies of "Flexible AC Transmission Systems (FACTS)" devices and "Distributed Energy Resources (DERS)." In addition to these infrastructure issues, a lack of situational awareness by system operators can cause major power outages as evidenced by the August 14, 2003 widespread North American blackout. This and many other recent major outages have highlighted the inadequacies of existing power system indexes. In this work, a novel "Index-based reactive compensation scheme" appropriate for both on-line and off-line computation of grid status has been developed. A new voltage stability index (Ls-index) suitable for long transmission lines was developed, simulated, and compared to the existing two-machine modeled L-index. This showed the effect of long distance power wheeling amongst regional transmission organizations. The dissertation further provided models for index modulated voltage source converters (VSC) and index-based load flow analysis of both FACTS and microgrid interconnected power systems using the Newton-Raphson's load flow model incorporated with multi-FACTS devices. The developed package has been made user-friendly through the embodiment of interactive graphical user interface and implemented on the IEEE 14, 30, and 300 bus systems. The results showed reactive compensation has system wide-effect, provided readily accessible system status indicators, ensured seamless DERs interconnection through new islanding modes and enhanced VSC utilization. These outcomes may contribute

  4. Functional Allocation for Ground-Based Automated Separation Assurance in NextGen

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas; Mercer, Joey; Martin, Lynne; Homola, Jeffrey; Cabrall, Christopher; Brasil, Connie

    2010-01-01

    As part of an ongoing research effort into functional allocation in a NextGen environment, a controller-in-the-loop study on ground-based automated separation assurance was conducted at NASA Ames' Airspace Operations Laboratory in February 2010. Participants included six FAA front line managers, who are currently certified professional controllers and four recently retired controllers. Traffic scenarios were 15 and 30 minutes long where controllers interacted with advanced technologies for ground-based separation assurance, weather avoidance, and arrival metering. The automation managed the separation by resolving conflicts automatically and involved controllers only by exception, e.g., when the automated resolution would have been outside preset limits. Results from data analyses show that workload was low despite high levels of traffic, Operational Errors did occur but were closely tied to local complexity, and safety acceptability ratings varied with traffic levels. Positive feedback was elicited for the overall concept with discussion on the proper allocation of functions and trust in automation.

  5. Fuzzy-logic-based resource allocation for isolated and multiple platforms

    NASA Astrophysics Data System (ADS)

    Smith, James F., III; Rhyne, Robert D., II

    2000-08-01

    Modern naval battle forces generally include many different platforms each with its own sensors, radar, ESM, and communications. The sharing of information measured by local sensors via communication links across the battle group should allow for optimal or near optimal decision. The survival of the battle group or members of the group depends on the automatic real-time allocation of various resources. A fuzzy logic algorithm has been developed that automatically allocates electronic attack resources in real- time. The particular approach to fuzzy logic that is used is the fuzzy decision tree, a generalization of the standard artificial intelligence technique of decision trees. The controller must be able to make decisions based on rules provided by experts. The fuzzy logic approach allows the direct incorporation of expertise forming a fuzzy linguistic description, i.e. a formal representation of the system in terms of fuzzy if-then rules. Genetic algorithm based optimization is conducted to determine the form of the membership functions for the fuzzy root concepts. The isolated platform and multi platform resource manager models are discussed as well as the underlying multi-platform communication model. The resource manager is shown to exhibit excellent performance under many demanding scenarios.

  6. K-Shortest-Path-Based Evacuation Routing with Police Resource Allocation in City Transportation Networks

    PubMed Central

    He, Yunyue; Liu, Zhong; Shi, Jianmai; Wang, Yishan; Zhang, Jiaming; Liu, Jinyuan

    2015-01-01

    Emergency evacuation aims to transport people from dangerous places to safe shelters as quickly as possible. Police play an important role in the evacuation process, as they can handle traffic accidents immediately and help people move smoothly on roads. This paper investigates an evacuation routing problem that involves police resource allocation. We propose a novel k-th-shortest-path-based technique that uses explicit congestion control to optimize evacuation routing and police resource allocation. A nonlinear mixed-integer programming model is presented to formulate the problem. The model’s objective is to minimize the overall evacuation clearance time. Two algorithms are given to solve the problem. The first one linearizes the original model and solves the linearized problem with CPLEX. The second one is a heuristic algorithm that uses a police resource utilization efficiency index to directly solve the original model. This police resource utilization efficiency index significantly aids in the evaluation of road links from an evacuation throughput perspective. The proposed algorithms are tested with a number of examples based on real data from cities of different sizes. The computational results show that the police resource utilization efficiency index is very helpful in finding near-optimal solutions. Additionally, comparing the performance of the heuristic algorithm and the linearization method by using randomly generated examples indicates that the efficiency of the heuristic algorithm is superior. PMID:26226109

  7. A secure biometrics-based authentication scheme for telecare medicine information systems.

    PubMed

    Yan, Xiaopeng; Li, Weiheng; Li, Ping; Wang, Jiantao; Hao, Xinhong; Gong, Peng

    2013-10-01

    The telecare medicine information system (TMIS) allows patients and doctors to access medical services or medical information at remote sites. Therefore, it could bring us very big convenient. To safeguard patients' privacy, authentication schemes for the TMIS attracted wide attention. Recently, Tan proposed an efficient biometrics-based authentication scheme for the TMIS and claimed their scheme could withstand various attacks. However, in this paper, we point out that Tan's scheme is vulnerable to the Denial-of-Service attack. To enhance security, we also propose an improved scheme based on Tan's work. Security and performance analysis shows our scheme not only could overcome weakness in Tan's scheme but also has better performance. PMID:23996083

  8. An improved biometrics-based authentication scheme for telecare medical information systems.

    PubMed

    Guo, Dianli; Wen, Qiaoyan; Li, Wenmin; Zhang, Hua; Jin, Zhengping

    2015-03-01

    Telecare medical information system (TMIS) offers healthcare delivery services and patients can acquire their desired medical services conveniently through public networks. The protection of patients' privacy and data confidentiality are significant. Very recently, Mishra et al. proposed a biometrics-based authentication scheme for telecare medical information system. Their scheme can protect user privacy and is believed to resist a range of network attacks. In this paper, we analyze Mishra et al.'s scheme and identify that their scheme is insecure to against known session key attack and impersonation attack. Thereby, we present a modified biometrics-based authentication scheme for TMIS to eliminate the aforementioned faults. Besides, we demonstrate the completeness of the proposed scheme through BAN-logic. Compared to the related schemes, our protocol can provide stronger security and it is more practical. PMID:25663481

  9. High-capacity and low-cost long-reach OFDMA PON based on distance-adaptive bandwidth allocation.

    PubMed

    Hu, Xiaofeng; Cao, Pan; Wu, Jiayang; Mao, Junming; Lv, Jianxin; Jiang, Yuling; Qiu, Ciyuan; Tremblay, Christine; Su, Yikai

    2015-01-26

    We propose and experimentally demonstrate a distance-adaptive bandwidth allocation scheme to realize high-capacity long-reach orthogonal frequency division multiple access passive optical network (OFDMA PON) with cost-effective electro-absorption modulator (EAM). In our scheme, the subcarriers in downstream OFDM signal are properly allocated to the optical network units (ONUs) with different fiber transmission lengths. By this means, the detrimental influence of power fading induced by dispersion and chirp can be avoided, thus all OFDM subcarriers can be modulated with high-order quadrature amplitude modulation (QAM) format, leading to a high transmission capacity. A proof-of-concept experiment is performed, in which three ONUs with transmission distances of 25, 50, and 100 km are assigned with different subcarriers, respectively. By using distance-adaptive bandwidth allocation technique, an OFDM signal of 34.5 Gb/s is successfully delivered to the ONUs with a bit error ratio (BER) lower than 2 × 10(-3). PMID:25835883

  10. Linear Models Based on Noisy Data and the Frisch Scheme*

    PubMed Central

    Ning, Lipeng; Georgiou, Tryphon T.; Tannenbaum, Allen; Boyd, Stephen P.

    2016-01-01

    We address the problem of identifying linear relations among variables based on noisy measurements. This is a central question in the search for structure in large data sets. Often a key assumption is that measurement errors in each variable are independent. This basic formulation has its roots in the work of Charles Spearman in 1904 and of Ragnar Frisch in the 1930s. Various topics such as errors-in-variables, factor analysis, and instrumental variables all refer to alternative viewpoints on this problem and on ways to account for the anticipated way that noise enters the data. In the present paper we begin by describing certain fundamental contributions by the founders of the field and provide alternative modern proofs to certain key results. We then go on to consider a modern viewpoint and novel numerical techniques to the problem. The central theme is expressed by the Frisch–Kalman dictum, which calls for identifying a noise contribution that allows a maximal number of simultaneous linear relations among the noise-free variables—a rank minimization problem. In the years since Frisch’s original formulation, there have been several insights, including trace minimization as a convenient heuristic to replace rank minimization. We discuss convex relaxations and theoretical bounds on the rank that, when met, provide guarantees for global optimality. A complementary point of view to this minimum-rank dictum is presented in which models are sought leading to a uniformly optimal quadratic estimation error for the error-free variables. Points of contact between these formalisms are discussed, and alternative regularization schemes are presented. PMID:27168672

  11. An arbitrated quantum signature scheme based on entanglement swapping with signer anonymity

    NASA Astrophysics Data System (ADS)

    Li, Wei; Fan, Ming-Yu; Wang, Guang-Wei

    2012-12-01

    In this paper an arbitrated quantum signature scheme based on entanglement swapping is proposed. In this scheme a message to be signed is coded with unitary operators. Combining quantum measurement with quantum encryption, the signer can generate the signature for a given message. Combining the entangled states generated by the TTP's Bell measurement with the signature information, the verifier can verify the authentication of a signature through a single quantum state measurement. Compared with previous schemes, our scheme is more efficient and less complex, furthermore, our scheme can ensure the anonymity of the signer.

  12. A chaotic map-based authentication scheme for telecare medicine information systems.

    PubMed

    Hao, Xinhong; Wang, Jiantao; Yang, Qinghai; Yan, Xiaopeng; Li, Ping

    2013-04-01

    With the development of Internet, patients could enjoy health-care delivery services through telecare medicine information systems (TMIS) in their home. To control the access to remote medical servers' resources, many authentication schemes using smart cards have been proposed. However, the performance of these schemes is not satisfactory since modular exponential operations are used in these schemes. In the paper, we propose a chaotic map-based authentication scheme for telecare medicine information systems. The security and performance analysis shows our scheme is more suitable for TMIS. PMID:23334801

  13. Agent-based evacuation simulation for spatial allocation assessment of urban shelters

    NASA Astrophysics Data System (ADS)

    Yu, Jia; Wen, Jiahong; Jiang, Yong

    2015-12-01

    The construction of urban shelters is one of the most important work in urban planning and disaster prevention. The spatial allocation assessment is a fundamental pre-step for spatial location-allocation of urban shelters. This paper introduces a new method which makes use of agent-based technology to implement evacuation simulation so as to conduct dynamic spatial allocation assessment of urban shelters. The method can not only accomplish traditional geospatial evaluation for urban shelters, but also simulate the evacuation process of the residents to shelters. The advantage of utilizing this method lies into three aspects: (1) the evacuation time of each citizen from a residential building to the shelter can be estimated more reasonably; (2) the total evacuation time of all the residents in a region is able to be obtained; (3) the road congestions in evacuation in sheltering can be detected so as to take precautionary measures to prevent potential risks. In this study, three types of agents are designed: shelter agents, government agents and resident agents. Shelter agents select specified land uses as shelter candidates for different disasters. Government agents delimitate the service area of each shelter, in other words, regulate which shelter a person should take, in accordance with the administrative boundaries and road distance between the person's position and the location of the shelter. Resident agents have a series of attributes, such as ages, positions, walking speeds, and so on. They also have several behaviors, such as reducing speed when walking in the crowd, helping old people and children, and so on. Integrating these three types of agents which are correlated with each other, evacuation procedures can be simulated and dynamic allocation assessment of shelters will be achieved. A case study in Jing'an District, Shanghai, China, was conducted to demonstrate the feasibility of the method. A scenario of earthquake disaster which occurs in nighttime

  14. A secure quantum group signature scheme based on Bell states

    NASA Astrophysics Data System (ADS)

    Zhang, Kejia; Song, Tingting; Zuo, Huijuan; Zhang, Weiwei

    2013-04-01

    In this paper, we propose a new secure quantum group signature with Bell states, which may have applications in e-payment system, e-government, e-business, etc. Compared with the recent quantum group signature protocols, our scheme is focused on the most general situation in practice, i.e. only the arbitrator is trusted and no intermediate information needs to be stored in the signing phase to ensure the security. Furthermore, our scheme has achieved all the characteristics of group signature—anonymity, verifiability, traceability, unforgetability and undeniability, by using some current developed quantum and classical technologies. Finally, a feasible security analysis model for quantum group signature is presented.

  15. Dynamic Allocation of SPM Based on Time-Slotted Cache Conflict Graph for System Optimization

    NASA Astrophysics Data System (ADS)

    Wu, Jianping; Ling, Ming; Zhang, Yang; Mei, Chen; Wang, Huan

    This paper proposes a novel dynamic Scratch-pad Memory allocation strategy to optimize the energy consumption of the memory sub-system. Firstly, the whole program execution process is sliced into several time slots according to the temporal dimension; thereafter, a Time-Slotted Cache Conflict Graph (TSCCG) is introduced to model the behavior of Data Cache (D-Cache) conflicts within each time slot. Then, Integer Nonlinear Programming (INP) is implemented, which can avoid time-consuming linearization process, to select the most profitable data pages. Virtual Memory System (VMS) is adopted to remap those data pages, which will cause severe Cache conflicts within a time slot, to SPM. In order to minimize the swapping overhead of dynamic SPM allocation, a novel SPM controller with a tightly coupled DMA is introduced to issue the swapping operations without CPU's intervention. Last but not the least, this paper discusses the fluctuation of system energy profit based on different MMU page size as well as the Time Slot duration quantitatively. According to our design space exploration, the proposed method can optimize all of the data segments, including global data, heap and stack data in general, and reduce the total energy consumption by 27.28% on average, up to 55.22% with a marginal performance promotion. And comparing to the conventional static CCG (Cache Conflicts Graph), our approach can obtain 24.7% energy profit on average, up to 30.5% with a sight boost in performance.

  16. Risk-based objectives for the allocation of chemical, biological, and radiological air emissions sensors.

    PubMed

    Lambert, James H; Farrington, Mark W

    2006-12-01

    This article addresses the problem of allocating devices for localized hazard protection across a region. Each identical device provides only local protection, and the devices serve localities that are exposed to nonidentical intensities of hazard. A method for seeking the optimal allocation Policy Decisions is described, highlighting the potentially competing objectives of maximizing local risk reductions and coverage risk reductions. The metric for local risk reductions is the sum of the local economic risks avoided. The metric for coverage risk reductions is adapted from the p-median problem and equal to the sum of squares of the distances from all unserved localities to their closest associated served locality. Three graphical techniques for interpreting the Policy Decisions are presented. The three linked graphical techniques are applied serially. The first technique identifies Policy Decisions that are nearly Pareto optimal. The second identifies locations where sensor placements are most justified, based on a risk-cost-benefit analysis under uncertainty. The third displays the decision space for any particular policy decision. The method is illustrated in an application to chemical, biological, and/or radiological weapon sensor placement, but has implications for disaster preparedness, transportation safety, and other arenas of public safety. PMID:17184404

  17. 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. PMID:27330910

  18. A swarm intelligence based memetic algorithm for task allocation in distributed systems

    NASA Astrophysics Data System (ADS)

    Sarvizadeh, Raheleh; Haghi Kashani, Mostafa

    2011-12-01

    This paper proposes a Swarm Intelligence based Memetic algorithm for Task Allocation and scheduling in distributed systems. The tasks scheduling in distributed systems is known as an NP-complete problem. Hence, many genetic algorithms have been proposed for searching optimal solutions from entire solution space. However, these existing approaches are going to scan the entire solution space without considering the techniques that can reduce the complexity of the optimization. Spending too much time for doing scheduling is considered the main shortcoming of these approaches. Therefore, in this paper memetic algorithm has been used to cope with this shortcoming. With regard to load balancing efficiently, Bee Colony Optimization (BCO) has been applied as local search in the proposed memetic algorithm. Extended experimental results demonstrated that the proposed method outperformed the existing GA-based method in terms of CPU utilization.

  19. A swarm intelligence based memetic algorithm for task allocation in distributed systems

    NASA Astrophysics Data System (ADS)

    Sarvizadeh, Raheleh; Haghi Kashani, Mostafa

    2012-01-01

    This paper proposes a Swarm Intelligence based Memetic algorithm for Task Allocation and scheduling in distributed systems. The tasks scheduling in distributed systems is known as an NP-complete problem. Hence, many genetic algorithms have been proposed for searching optimal solutions from entire solution space. However, these existing approaches are going to scan the entire solution space without considering the techniques that can reduce the complexity of the optimization. Spending too much time for doing scheduling is considered the main shortcoming of these approaches. Therefore, in this paper memetic algorithm has been used to cope with this shortcoming. With regard to load balancing efficiently, Bee Colony Optimization (BCO) has been applied as local search in the proposed memetic algorithm. Extended experimental results demonstrated that the proposed method outperformed the existing GA-based method in terms of CPU utilization.

  20. A Wavelet Based Dissipation Method for ALE Schemes

    SciTech Connect

    Cabot, B; Eliason, D.; Jameson, L.

    2000-07-01

    Wavelet analysis is natural tool to detect the presence of numerical noise, shocks and other features which might drive a calculation to become unstable. Here we suggest ways where wavelets can be used effectively to define a dissipation flag to replace dissipation flags traditionally used in ALE numerical schemes.

  1. Copyright protection scheme for still images based on an image pinned field

    NASA Astrophysics Data System (ADS)

    Lee, Mn-Ta; Chang, Hsuan T.

    2010-09-01

    Watermark embedding processes usually result in some degradation of the digital multimedia contents. Hence, they are not suitable for valuable and sensitive digital multimedia contents. Therefore, schemes combining signature with digital watermarking-like techniques have been proposed. Based on the general model for these combined schemes, a new scheme for image copyright protection by utilizing the pinned field of the protected image is proposed in this paper. The pinned field explores the texture information of the images and can be used to enhance the watermark robustness. Experimental results show that the proposed scheme works well under different signal-processing and geometric transformation attacks. On the other hand, in comparison with related schemes in the literature, our proposed scheme also has better performance. Furthermore, the proposed scheme is robust to both JPEG lossy compression and additive Gaussian noise.

  2. Intra-generational Redistribution under Public Pension Planning Based on Generation-based Funding Scheme

    NASA Astrophysics Data System (ADS)

    Banjo, Daisuke; Tamura, Hiroyuki; Murata, Tadahiko

    In this paper, we propose a method of determining the pension in the generation-based funding scheme. In this proposal, we include two types of pensions in the scheme. One is the payment-amount related pension and the other is the payment-frequency related pension. We set the ratio of the total amount of payment-amount related pension to the total amount of both pensions, and simulate income gaps and the relationship between contributions and benefits for each individual when the proposed method is applied.

  3. A Soft-Hard Combination-Based Cooperative Spectrum Sensing Scheme for Cognitive Radio Networks

    PubMed Central

    Do, Nhu Tri; An, Beongku

    2015-01-01

    In this paper we propose a soft-hard combination scheme, called SHC scheme, for cooperative spectrum sensing in cognitive radio networks. The SHC scheme deploys a cluster based network in which Likelihood Ratio Test (LRT)-based soft combination is applied at each cluster, and weighted decision fusion rule-based hard combination is utilized at the fusion center. The novelties of the SHC scheme are as follows: the structure of the SHC scheme reduces the complexity of cooperative detection which is an inherent limitation of soft combination schemes. By using the LRT, we can detect primary signals in a low signal-to-noise ratio regime (around an average of −15 dB). In addition, the computational complexity of the LRT is reduced since we derive the closed-form expression of the probability density function of LRT value. The SHC scheme also takes into account the different effects of large scale fading on different users in the wide area network. The simulation results show that the SHC scheme not only provides the better sensing performance compared to the conventional hard combination schemes, but also reduces sensing overhead in terms of reporting time compared to the conventional soft combination scheme using the LRT. PMID:25688589

  4. A provably-secure ECC-based authentication scheme for wireless sensor networks.

    PubMed

    Nam, Junghyun; Kim, Moonseong; Paik, Juryon; Lee, Youngsook; Won, Dongho

    2014-01-01

    A smart-card-based user authentication scheme for wireless sensor networks (in short, a SUA-WSN scheme) is designed to restrict access to the sensor data only to users who are in possession of both a smart card and the corresponding password. While a significant number of SUA-WSN schemes have been suggested in recent years, their intended security properties lack formal definitions and proofs in a widely-accepted model. One consequence is that SUA-WSN schemes insecure against various attacks have proliferated. In this paper, we devise a security model for the analysis of SUA-WSN schemes by extending the widely-accepted model of Bellare, Pointcheval and Rogaway (2000). Our model provides formal definitions of authenticated key exchange and user anonymity while capturing side-channel attacks, as well as other common attacks. We also propose a new SUA-WSN scheme based on elliptic curve cryptography (ECC), and prove its security properties in our extended model. To the best of our knowledge, our proposed scheme is the first SUA-WSN scheme that provably achieves both authenticated key exchange and user anonymity. Our scheme is also computationally competitive with other ECC-based (non-provably secure) schemes. PMID:25384009

  5. A soft-hard combination-based cooperative spectrum sensing scheme for cognitive radio networks.

    PubMed

    Do, Nhu Tri; An, Beongku

    2015-01-01

    In this paper we propose a soft-hard combination scheme, called SHC scheme, for cooperative spectrum sensing in cognitive radio networks. The SHC scheme deploys a cluster based network in which Likelihood Ratio Test (LRT)-based soft combination is applied at each cluster, and weighted decision fusion rule-based hard combination is utilized at the fusion center. The novelties of the SHC scheme are as follows: the structure of the SHC scheme reduces the complexity of cooperative detection which is an inherent limitation of soft combination schemes. By using the LRT, we can detect primary signals in a low signal-to-noise ratio regime (around an average of -15 dB). In addition, the computational complexity of the LRT is reduced since we derive the closed-form expression of the probability density function of LRT value. The SHC scheme also takes into account the different effects of large scale fading on different users in the wide area network. The simulation results show that the SHC scheme not only provides the better sensing performance compared to the conventional hard combination schemes, but also reduces sensing overhead in terms of reporting time compared to the conventional soft combination scheme using the LRT. PMID:25688589

  6. A Provably-Secure ECC-Based Authentication Scheme for Wireless Sensor Networks

    PubMed Central

    Nam, Junghyun; Kim, Moonseong; Paik, Juryon; Lee, Youngsook; Won, Dongho

    2014-01-01

    A smart-card-based user authentication scheme for wireless sensor networks (in short, a SUA-WSN scheme) is designed to restrict access to the sensor data only to users who are in possession of both a smart card and the corresponding password. While a significant number of SUA-WSN schemes have been suggested in recent years, their intended security properties lack formal definitions and proofs in a widely-accepted model. One consequence is that SUA-WSN schemes insecure against various attacks have proliferated. In this paper, we devise a security model for the analysis of SUA-WSN schemes by extending the widely-accepted model of Bellare, Pointcheval and Rogaway (2000). Our model provides formal definitions of authenticated key exchange and user anonymity while capturing side-channel attacks, as well as other common attacks. We also propose a new SUA-WSN scheme based on elliptic curve cryptography (ECC), and prove its security properties in our extended model. To the best of our knowledge, our proposed scheme is the first SUA-WSN scheme that provably achieves both authenticated key exchange and user anonymity. Our scheme is also computationally competitive with other ECC-based (non-provably secure) schemes. PMID:25384009

  7. Modeling and Simulation of Water Allocation System Based on Simulated Annealing Hybrid Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Zhu, Jiulong; Wang, Shijun

    Presently water resource in most watersheds in China is distributed in terms of administrative instructions. This kind of allocation method has many disadvantages and hampers the instructional effect of market mechanism on water allocation. The paper studies South-to-North Water Transfer Project and discusses water allocation of the node lakes along the Project. Firstly, it advanced four assumptions. Secondly, it analyzed constraint conditions of water allocation in terms of present state of water allocation in China. Thirdly, it established a goal model of water allocation and set up a systematic model from the angle of comprehensive profits of water utilization and profits of the node lakes. Fourthly, it discussed calculation method of the model by means of Simulated Annealing Hybrid Genetic Algorithm (SHGA). Finally, it validated the rationality and validity of the model by a simulation testing.

  8. A continuous and prognostic convection scheme based on buoyancy, PCMT

    NASA Astrophysics Data System (ADS)

    Guérémy, Jean-François; Piriou, Jean-Marcel

    2016-04-01

    A new and consistent convection scheme (PCMT: Prognostic Condensates Microphysics and Transport), providing a continuous and prognostic treatment of this atmospheric process, is described. The main concept ensuring the consistency of the whole system is the buoyancy, key element of any vertical motion. The buoyancy constitutes the forcing term of the convective vertical velocity, which is then used to define the triggering condition, the mass flux, and the rates of entrainment-detrainment. The buoyancy is also used in its vertically integrated form (CAPE) to determine the closure condition. The continuous treatment of convection, from dry thermals to deep precipitating convection, is achieved with the help of a continuous formulation of the entrainment-detrainment rates (depending on the convective vertical velocity) and of the CAPE relaxation time (depending on the convective over-turning time). The convective tendencies are directly expressed in terms of condensation and transport. Finally, the convective vertical velocity and condensates are fully prognostic, the latter being treated using the same microphysics scheme as for the resolved condensates but considering the convective environment. A Single Column Model (SCM) validation of this scheme is shown, allowing detailed comparisons with observed and explicitly simulated data. Four cases covering the convective spectrum are considered: over ocean, sensitivity to environmental moisture (S. Derbyshire) non precipitating shallow convection to deep precipitating convection, trade wind shallow convection (BOMEX) and strato-cumulus (FIRE), together with an entire continental diurnal cycle of convection (ARM). The emphasis is put on the characteristics of the scheme which enable a continuous treatment of convection. Then, a 3D LAM validation is presented considering an AMMA case with both observations and a CRM simulation using the same initial and lateral conditions as for the parameterized one. Finally, global

  9. Electric power grid control using a market-based resource allocation system

    DOEpatents

    Chassin, David P.

    2015-07-21

    Disclosed herein are representative embodiments of methods, apparatus, and systems for distributing a resource (such as electricity) using a resource allocation system. In one exemplary embodiment, a plurality of requests for electricity are received from a plurality of end-use consumers. The requests indicate a requested quantity of electricity and a consumer-requested index value indicative of a maximum price a respective end-use consumer will pay for the requested quantity of electricity. A plurality of offers for supplying electricity are received from a plurality of resource suppliers. The offers indicate an offered quantity of electricity and a supplier-requested index value indicative of a minimum price for which a respective supplier will produce the offered quantity of electricity. A dispatched index value is computed at which electricity is to be supplied based at least in part on the consumer-requested index values and the supplier-requested index values.

  10. Electric power grid control using a market-based resource allocation system

    DOEpatents

    Chassin, David P

    2014-01-28

    Disclosed herein are representative embodiments of methods, apparatus, and systems for distributing a resource (such as electricity) using a resource allocation system. In one exemplary embodiment, a plurality of requests for electricity are received from a plurality of end-use consumers. The requests indicate a requested quantity of electricity and a consumer-requested index value indicative of a maximum price a respective end-use consumer will pay for the requested quantity of electricity. A plurality of offers for supplying electricity are received from a plurality of resource suppliers. The offers indicate an offered quantity of electricity and a supplier-requested index value indicative of a minimum price for which a respective supplier will produce the offered quantity of electricity. A dispatched index value is computed at which electricity is to be supplied based at least in part on the consumer-requested index values and the supplier-requested index values.

  11. Using bi-directional communications in a market-based resource allocation system

    DOEpatents

    Chassin, David P; Pratt, Robert G

    2015-05-05

    Disclosed herein are representative embodiments of methods, apparatus, and systems for distributing a resource (such as electricity) using a resource allocation system. In one exemplary embodiment, a plurality of requests for electricity are received from a plurality of end-use consumers. The requests indicate a requested quantity of electricity and a consumer-requested index value indicative of a maximum price a respective end-use consumer will pay for the requested quantity of electricity. A plurality of offers for supplying electricity are received from a plurality of resource suppliers. The offers indicate an offered quantity of electricity and a supplier-requested index value indicative of a minimum price for which a respective supplier will produce the offered quantity of electricity. A dispatched index value is computed at which electricity is to be supplied based at least in part on the consumer-requested index values and the supplier-requested index values.

  12. Using one-way communications in a market-based resource allocation system

    DOEpatents

    Chassin, David P.; Pratt, Robert G.

    2014-07-22

    Disclosed herein are representative embodiments of methods, apparatus, and systems for distributing a resource (such as electricity) using a resource allocation system. In one exemplary embodiment, a plurality of requests for electricity are received from a plurality of end-use consumers. The requests indicate a requested quantity of electricity and a consumer-requested index value indicative of a maximum price a respective end-use consumer will pay for the requested quantity of electricity. A plurality of offers for supplying electricity are received from a plurality of resource suppliers. The offers indicate an offered quantity of electricity and a supplier-requested index value indicative of a minimum price for which a respective supplier will produce the offered quantity of electricity. A dispatched index value is computed at which electricity is to be supplied based at least in part on the consumer-requested index values and the supplier-requested index values.

  13. Using bi-directional communications in a market-based resource allocation system

    DOEpatents

    Chassin, David P; Pratt, Robert G

    2014-04-01

    Disclosed herein are representative embodiments of methods, apparatus, and systems for distributing a resource (such as electricity) using a resource allocation system. In one exemplary embodiment, a plurality of requests for electricity are received from a plurality of end-use consumers. The requests indicate a requested quantity of electricity and a consumer-requested index value indicative of a maximum price a respective end-use consumer will pay for the requested quantity of electricity. A plurality of offers for supplying electricity are received from a plurality of resource suppliers. The offers indicate an offered quantity of electricity and a supplier-requested index value indicative of a minimum price for which a respective supplier will produce the offered quantity of electricity. A dispatched index value is computed at which electricity is to be supplied based at least in part on the consumer-requested index values and the supplier-requested index values.

  14. Using bi-directional communications in a market-based resource allocation system

    DOEpatents

    Chassin, David P.; Pratt, Robert G.

    2015-09-08

    Disclosed herein are representative embodiments of methods, apparatus, and systems for distributing a resource (such as electricity) using a resource allocation system. In one exemplary embodiment, a plurality of requests for electricity are received from a plurality of end-use consumers. The requests indicate a requested quantity of electricity and a consumer-requested index value indicative of a maximum price a respective end-use consumer will pay for the requested quantity of electricity. A plurality of offers for supplying electricity are received from a plurality of resource suppliers. The offers indicate an offered quantity of electricity and a supplier-requested index value indicative of a minimum price for which a respective supplier will produce the offered quantity of electricity. A dispatched index value is computed at which electricity is to be supplied based at least in part on the consumer-requested index values and the supplier-requested index values.

  15. Optimality versus stability in water resource allocation.

    PubMed

    Read, Laura; Madani, Kaveh; Inanloo, Bahareh

    2014-01-15

    Water allocation is a growing concern in a developing world where limited resources like fresh water are in greater demand by more parties. Negotiations over allocations often involve multiple groups with disparate social, economic, and political status and needs, who are seeking a management solution for a wide range of demands. Optimization techniques for identifying the Pareto-optimal (social planner solution) to multi-criteria multi-participant problems are commonly implemented, although often reaching agreement for this solution is difficult. In negotiations with multiple-decision makers, parties who base decisions on individual rationality may find the social planner solution to be unfair, thus creating a need to evaluate the willingness to cooperate and practicality of a cooperative allocation solution, i.e., the solution's stability. This paper suggests seeking solutions for multi-participant resource allocation problems through an economics-based power index allocation method. This method can inform on allocation schemes that quantify a party's willingness to participate in a negotiation rather than opt for no agreement. Through comparison of the suggested method with a range of distance-based multi-criteria decision making rules, namely, least squares, MAXIMIN, MINIMAX, and compromise programming, this paper shows that optimality and stability can produce different allocation solutions. The mismatch between the socially-optimal alternative and the most stable alternative can potentially result in parties leaving the negotiation as they may be too dissatisfied with their resource share. This finding has important policy implications as it justifies why stakeholders may not accept the socially optimal solution in practice, and underlies the necessity of considering stability where it may be more appropriate to give up an unstable Pareto-optimal solution for an inferior stable one. Authors suggest assessing the stability of an allocation solution as an

  16. A Quantum Proxy Weak Blind Signature Scheme Based on Controlled Quantum Teleportation

    NASA Astrophysics Data System (ADS)

    Cao, Hai-Jing; Yu, Yao-Feng; Song, Qin; Gao, Lan-Xiang

    2015-04-01

    Proxy blind signature is applied to the electronic paying system, electronic voting system, mobile agent system, security of internet, etc. A quantum proxy weak blind signature scheme is proposed in this paper. It is based on controlled quantum teleportation. Five-qubit entangled state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to implement message blinding, so it could guarantee not only the unconditional security of the scheme but also the anonymity of the messages owner.

  17. A Quantum Proxy Weak Blind Signature Scheme Based on Controlled Quantum Teleportation

    NASA Astrophysics Data System (ADS)

    Cao, Hai-Jing; Yu, Yao-Feng; Song, Qin; Gao, Lan-Xiang

    2014-09-01

    Proxy blind signature is applied to the electronic paying system, electronic voting system, mobile agent system, security of internet, etc. A quantum proxy weak blind signature scheme is proposed in this paper. It is based on controlled quantum teleportation. Five-qubit entangled state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to implement message blinding, so it could guarantee not only the unconditional security of the scheme but also the anonymity of the messages owner.

  18. Efficient Spin Injector Scheme Based on Heusler Materials

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

    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. Force feedback microscopy based on an optical beam deflection scheme

    NASA Astrophysics Data System (ADS)

    Vitorino, Miguel V.; Carpentier, Simon; Costa, Luca; Rodrigues, Mario S.

    2014-07-01

    Force feedback microscopy circumvents the jump to contact in atomic force microscopy when using soft cantilevers and quantitatively measures the interaction properties at the nanoscale by simultaneously providing force, force gradient, and dissipation. The force feedback microscope developed so far used an optical cavity to measure the tip displacement. In this Letter, we show that the more conventional optical beam deflection scheme can be used to the same purpose. With this instrument, we have followed the evolution of the Brownian motion of the tip under the influence of a water bridge.

  20. Force feedback microscopy based on an optical beam deflection scheme

    SciTech Connect

    Vitorino, Miguel V.; Rodrigues, Mario S.; Carpentier, Simon; Costa, Luca

    2014-07-07

    Force feedback microscopy circumvents the jump to contact in atomic force microscopy when using soft cantilevers and quantitatively measures the interaction properties at the nanoscale by simultaneously providing force, force gradient, and dissipation. The force feedback microscope developed so far used an optical cavity to measure the tip displacement. In this Letter, we show that the more conventional optical beam deflection scheme can be used to the same purpose. With this instrument, we have followed the evolution of the Brownian motion of the tip under the influence of a water bridge.

  1. Remodulation scheme based on a two-section reflective SOA

    NASA Astrophysics Data System (ADS)

    Guiying, Jiang; Lirong, Huang

    2014-05-01

    A simple and cost-effective remodulation scheme using a two-section reflective semiconductor optical amplifier (RSOA) is proposed for a colorless optical network unit (ONU). Under proper injection currents, the front section functions as a modulator to upload the upstream signal while the rear section serves as a data eraser for efficient suppression of the downstream data. The dependences of the upstream transmission performance on the lengths and driven currents of the RSOA, the injection optical power and extinction ratio of the downstream are investigated. By optimizing these parameters, the downstream data can be more completely suppressed and the upstream transmission performance can be greatly improved.

  2. Transonic inviscid/turbulent airfoil flow simulations using a pressure based method with high order schemes

    NASA Astrophysics Data System (ADS)

    Zhou, Gang; Davidson, Lars; Olsson, Erik

    This paper presents computations of transonic aerodynamic flow simulations using a pressure-based Euler/Navier-Stokes solver. In this work emphasis is focused on the implementation of higher-order schemes such as QUICK, LUDS and MUSCL. A new scheme CHARM is proposed for convection approximation. Inviscid flow simulations are carried out for the airfoil NACA 0012. The CHARM scheme gives better resolution for the present inviscid case. The turbulent flow computations are carried out for the airfoil RAE 2822. Good results were obtained using QUICK scheme for mean motion equation combined with the MUSCL scheme for k and ɛ equations. No unphysical oscillations were observed. The results also show that the second-order and thir-dorder schemes yielded a comparable accuracy compared with the experimental data.

  3. A User Authentication Scheme Based on Elliptic Curves Cryptography for Wireless Ad Hoc Networks

    PubMed Central

    Chen, Huifang; Ge, Linlin; Xie, Lei

    2015-01-01

    The feature of non-infrastructure support in a wireless ad hoc network (WANET) makes it suffer from various attacks. Moreover, user authentication is the first safety barrier in a network. A mutual trust is achieved by a protocol which enables communicating parties to authenticate each other at the same time and to exchange session keys. For the resource-constrained WANET, an efficient and lightweight user authentication scheme is necessary. In this paper, we propose a user authentication scheme based on the self-certified public key system and elliptic curves cryptography for a WANET. Using the proposed scheme, an efficient two-way user authentication and secure session key agreement can be achieved. Security analysis shows that our proposed scheme is resilient to common known attacks. In addition, the performance analysis shows that our proposed scheme performs similar or better compared with some existing user authentication schemes. PMID:26184224

  4. A Data Gathering Scheme in Wireless Sensor Networks Based on Synchronization of Chaotic Spiking Oscillator Networks

    SciTech Connect

    Nakano, Hidehiro; Utani, Akihide; Miyauchi, Arata; Yamamoto, Hisao

    2011-04-19

    This paper studies chaos-based data gathering scheme in multiple sink wireless sensor networks. In the proposed scheme, each wireless sensor node has a simple chaotic oscillator. The oscillators generate spike signals with chaotic interspike intervals, and are impulsively coupled by the signals via wireless communication. Each wireless sensor node transmits and receives sensor information only in the timing of the couplings. The proposed scheme can exhibit various chaos synchronous phenomena and their breakdown phenomena, and can effectively gather sensor information with the significantly small number of transmissions and receptions compared with the conventional scheme. Also, the proposed scheme can flexibly adapt various wireless sensor networks not only with a single sink node but also with multiple sink nodes. This paper introduces our previous works. Through simulation experiments, we show effectiveness of the proposed scheme and discuss its development potential.

  5. A User Authentication Scheme Based on Elliptic Curves Cryptography for Wireless Ad Hoc Networks.

    PubMed

    Chen, Huifang; Ge, Linlin; Xie, Lei

    2015-01-01

    The feature of non-infrastructure support in a wireless ad hoc network (WANET) makes it suffer from various attacks. Moreover, user authentication is the first safety barrier in a network. A mutual trust is achieved by a protocol which enables communicating parties to authenticate each other at the same time and to exchange session keys. For the resource-constrained WANET, an efficient and lightweight user authentication scheme is necessary. In this paper, we propose a user authentication scheme based on the self-certified public key system and elliptic curves cryptography for a WANET. Using the proposed scheme, an efficient two-way user authentication and secure session key agreement can be achieved. Security analysis shows that our proposed scheme is resilient to common known attacks. In addition, the performance analysis shows that our proposed scheme performs similar or better compared with some existing user authentication schemes. PMID:26184224

  6. Scenario-Based Multi-Objective Optimum Allocation Model for Earthquake Emergency Shelters Using a Modified Particle Swarm Optimization Algorithm: A Case Study in Chaoyang District, Beijing, China

    PubMed Central

    Zhao, Xiujuan; Xu, Wei; Ma, Yunjia; Hu, Fuyu

    2015-01-01

    The correct location of earthquake emergency shelters and their allocation to residents can effectively reduce the number of casualties by providing safe havens and efficient evacuation routes during the chaotic period of the unfolding disaster. However, diverse and strict constraints and the discrete feasible domain of the required models make the problem of shelter location and allocation more difficult. A number of models have been developed to solve this problem, but there are still large differences between the models and the actual situation because the characteristics of the evacuees and the construction costs of the shelters have been excessively simplified. We report here the development of a multi-objective model for the allocation of residents to earthquake shelters by considering these factors using the Chaoyang district, Beijing, China as a case study. The two objectives of this model were to minimize the total weighted evacuation time from residential areas to a specified shelter and to minimize the total area of all the shelters. The two constraints were the shelter capacity and the service radius. Three scenarios were considered to estimate the number of people who would need to be evacuated. The particle swarm optimization algorithm was first modified by applying the von Neumann structure in former loops and global structure in later loops, and then used to solve this problem. The results show that increasing the shelter area can result in a large decrease in the total weighted evacuation time from scheme 1 to scheme 9 in scenario A, from scheme 1 to scheme 9 in scenario B, from scheme 1 to scheme 19 in scenario C. If the funding were not a limitation, then the final schemes of each scenario are the best solutions, otherwise the earlier schemes are more reasonable. The modified model proved to be useful for the optimization of shelter allocation, and the result can be used as a scientific reference for planning shelters in the Chaoyang district

  7. Determination of cost coefficients of a priority-based water allocation linear programming model - a network flow approach

    NASA Astrophysics Data System (ADS)

    Chou, F. N.-F.; Wu, C.-W.

    2014-05-01

    This paper presents a method to establish the objective function of a network flow programming model for simulating river-reservoir system operations and associated water allocation, with an emphasis on situations when the links other than demand or storage have to be assigned with nonzero cost coefficients. The method preserves the priorities defined by rule curves of reservoir, operational preferences for conveying water, allocation of storage among multiple reservoirs, and transbasin water diversions. Path enumeration analysis transforms these water allocation rules into linear constraints that can be solved to determine link cost coefficients. An approach to prune the original system into a reduced network is proposed to establish the precise constraints of nonzero cost coefficients, which can then be efficiently solved. The cost coefficients for the water allocation in the Feitsui and Shihmen reservoirs' joint operating system of northern Taiwan was adequately assigned by the proposed method. This case study demonstrates how practitioners can correctly utilize network-flow-based models to allocate water supply throughout complex systems that are subject to strict operating rules.

  8. Determination of cost coefficients of priority-based water allocation linear programming model - a network flow approach

    NASA Astrophysics Data System (ADS)

    Chou, F. N.-F.; Wu, C.-W.

    2013-12-01

    This paper presents a method to establish the objective function of a network flow programming model for simulating river/reservoir system operations and associated water allocation, with an emphasis on situations when the links other than demand or storage have to be assigned with nonzero cost coefficients. The method preserves the priorities defined by rule curves of reservoir, operational preferences for conveying water, allocation of storage among multiple reservoirs, and trans-basin water diversions. Path enumeration analysis transforms these water allocation rules into linear constraints that can be solved to determine link cost coefficients. An approach to prune the original system into a reduced network is proposed to establish the precise constraints of nonzero cost coefficients which can then be efficiently solved. The cost coefficients for the water allocation in the Feitsui and Shihmen Reservoirs joint operating system of northern Taiwan was adequately assigned by the proposed method. This case study demonstrates how practitioners can correctly utilize network-flow-based models to allocate water supply throughout complex systems that are subject to strict operating rules.

  9. Security Encryption Scheme for Communication of Web Based Control Systems

    NASA Astrophysics Data System (ADS)

    Robles, Rosslin John; Kim, Tai-Hoon

    A control system is a device or set of devices to manage, command, direct or regulate the behavior of other devices or systems. The trend in most systems is that they are connected through the Internet. Traditional Supervisory Control and Data Acquisition Systems (SCADA) is connected only in a limited private network Since the internet Supervisory Control and Data Acquisition Systems (SCADA) facility has brought a lot of advantages in terms of control, data viewing and generation. Along with these advantages, are security issues regarding web SCADA, operators are pushed to connect Control Systems through the internet. Because of this, many issues regarding security surfaced. In this paper, we discuss web SCADA and the issues regarding security. As a countermeasure, a web SCADA security solution using crossed-crypto-scheme is proposed to be used in the communication of SCADA components.

  10. Image edge detection based on adaptive lifting scheme

    NASA Astrophysics Data System (ADS)

    Xia, Ping; Xiang, Xuejun; Wan, Junli

    2009-10-01

    Image edge is because the gradation is the result of not continuously, is image's information basic characteristic, is also one of hot topics in image processing. This paper analyzes traditional arithmetic of image edge detection and existing problem, uses adaptive lifting wavelet analysis, adaptive adjusts the predict filter and the update filter according to information's partial characteristic, thus realizes the processing information accurate match; at the same time, improves the wavelet edge detection operator, realizes one kind to be suitable for the adaptive lifting scheme image edge detection's algorithm, and applies this method in the medicine image edge detection. The experiment results show that this paper's algorithm is better than the traditional algorithm effect.

  11. A novel dynamical community detection algorithm based on weighting scheme

    NASA Astrophysics Data System (ADS)

    Li, Ju; Yu, Kai; Hu, Ke

    2015-12-01

    Network dynamics plays an important role in analyzing the correlation between the function properties and the topological structure. In this paper, we propose a novel dynamical iteration (DI) algorithm, which incorporates the iterative process of membership vector with weighting scheme, i.e. weighting W and tightness T. These new elements can be used to adjust the link strength and the node compactness for improving the speed and accuracy of community structure detection. To estimate the optimal stop time of iteration, we utilize a new stability measure which is defined as the Markov random walk auto-covariance. We do not need to specify the number of communities in advance. It naturally supports the overlapping communities by associating each node with a membership vector describing the node's involvement in each community. Theoretical analysis and experiments show that the algorithm can uncover communities effectively and efficiently.

  12. Cryptanalysis of the Hwang-Lo-Lin Scheme Based on an ID-Based Cryptosystem and Its Improvement

    NASA Astrophysics Data System (ADS)

    Park, Haeryong; Chun, Kilsoo; Ahn, Seungho

    Hwang-Lo-Lin proposed a user identification scheme [3] based on the Maurer-Yacobi scheme [6] that is suitable for application to the mobile environment. Hwang-Lo-Lin argued that their scheme is secure against any attack. Against the Hwang-Lo-Lin argument, Liu-Horng-Liu showed that the Hwang-Lo-Lin scheme is insecure against a Liu-Horng-Liu attack mounted by an eavesdrop attacker. However, Liu-Horng-Liu did not propose any improved version of the original identification scheme which is still secure against the Liu-Horng-Liu attack. In this paper, we propose an identification scheme that can solve this problem and a non-interactive public key distribution scheme also.

  13. Working memory capacity accounts for the ability to switch between object-based and location-based allocation of visual attention.

    PubMed

    Bleckley, M Kathryn; Foster, Jeffrey L; Engle, Randall W

    2015-04-01

    Bleckley, Durso, Crutchfield, Engle, and Khanna (Psychonomic Bulletin & Review, 10, 884-889, 2003) found that visual attention allocation differed between groups high or low in working memory capacity (WMC). High-span, but not low-span, subjects showed an invalid-cue cost during a letter localization task in which the letter appeared closer to fixation than the cue, but not when the letter appeared farther from fixation than the cue. This suggests that low-spans allocated attention as a spotlight, whereas high-spans allocated their attention to objects. In this study, we tested whether utilizing object-based visual attention is a resource-limited process that is difficult for low-span individuals. In the first experiment, we tested the uses of object versus location-based attention with high and low-span subjects, with half of the subjects completing a demanding secondary load task. Under load, high-spans were no longer able to use object-based visual attention. A second experiment supported the hypothesis that these differences in allocation were due to high-spans using object-based allocation, whereas low-spans used location-based allocation. PMID:25421317

  14. A multihop key agreement scheme for wireless ad hoc networks based on channel characteristics.

    PubMed

    Hao, Zhuo; Zhong, Sheng; Yu, Nenghai

    2013-01-01

    A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks. PMID:23766725

  15. Security enhancement of a biometric based authentication scheme for telecare medicine information systems with nonce.

    PubMed

    Mishra, Dheerendra; Mukhopadhyay, Sourav; Kumari, Saru; Khan, Muhammad Khurram; Chaturvedi, Ankita

    2014-05-01

    Telecare medicine information systems (TMIS) present the platform to deliver clinical service door to door. The technological advances in mobile computing are enhancing the quality of healthcare and a user can access these services using its mobile device. However, user and Telecare system communicate via public channels in these online services which increase the security risk. Therefore, it is required to ensure that only authorized user is accessing the system and user is interacting with the correct system. The mutual authentication provides the way to achieve this. Although existing schemes are either vulnerable to attacks or they have higher computational cost while an scalable authentication scheme for mobile devices should be secure and efficient. Recently, Awasthi and Srivastava presented a biometric based authentication scheme for TMIS with nonce. Their scheme only requires the computation of the hash and XOR functions.pagebreak Thus, this scheme fits for TMIS. However, we observe that Awasthi and Srivastava's scheme does not achieve efficient password change phase. Moreover, their scheme does not resist off-line password guessing attack. Further, we propose an improvement of Awasthi and Srivastava's scheme with the aim to remove the drawbacks of their scheme. PMID:24771484

  16. A Multihop Key Agreement Scheme for Wireless Ad Hoc Networks Based on Channel Characteristics

    PubMed Central

    Yu, Nenghai

    2013-01-01

    A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks. PMID:23766725

  17. MDP-based resource allocation for triple-play transmission on xDSL systems

    NASA Astrophysics Data System (ADS)

    de Souza, Lamartine V.; de Carvalho, Glaucio H. S.; Cardoso, Diego L.; de Carvalho, Solon V.; Frances, Carlos R. L.; Costa, João C. W. A.; Riu, Jaume Rius i.

    2007-09-01

    Many broadband services are based on multimedia applications, such as voice over internet protocol (VoIP), video conferencing, video on demand (VoD), and internet protocol television (IPTV). The combination "triple-play" is often used with IPTV. It simply means offering voice, video and data. IPTV and others services uses digital broadband networks such as ADSL2+ (Asymmetric Digital Subscriber Line) and VDSL (Very High Rate DSL) to transmit the data. We have formulated a MDP (Markov Decision Process) for a triple-play transmission on DSL environment. In this paper, we establish the relationship between DSL transmission characteristics and its finite-state Markov model for a triple-play transmission system. This relationship can be used for a resource management for multimedia applications delivered through a broadband infrastructure. The solution to our optimization problem can be found using dynamic programming (DP) techniques, such as value iteration and its variants. Our study results in a transmission strategy that chooses the optimal resource allocation according the triple-play traffic requirements, defined in technical report TR-126 (Triple-Play Services Quality of Experience Requirements) from DSL Forum, minimizing quality of service (QoS) violations with respect to bandwidth. Three traffic classes (video, audio, and best effort internet data) are defined and analyzed. Our simulation results show parameters like as blocking probability for each class, link utilization and optimal control policies. The MDP-based approach provides a satisfactory way of resource management for a DSL system.

  18. An enhanced biometric-based authentication scheme for telecare medicine information systems using elliptic curve cryptosystem.

    PubMed

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

    2015-03-01

    The telecare medical information systems (TMISs) enable patients to conveniently enjoy telecare services at home. The protection of patient's privacy is a key issue due to the openness of communication environment. Authentication as a typical approach is adopted to guarantee confidential and authorized interaction between the patient and remote server. In order to achieve the goals, numerous remote authentication schemes based on cryptography have been presented. Recently, Arshad et al. (J Med Syst 38(12): 2014) presented a secure and efficient three-factor authenticated key exchange scheme to remedy the weaknesses of Tan et al.'s scheme (J Med Syst 38(3): 2014). In this paper, we found that once a successful off-line password attack that results in an adversary could impersonate any user of the system in Arshad et al.'s scheme. In order to thwart these security attacks, an enhanced biometric and smart card based remote authentication scheme for TMISs is proposed. In addition, the BAN logic is applied to demonstrate the completeness of the enhanced scheme. Security and performance analyses show that our enhanced scheme satisfies more security properties and less computational cost compared with previously proposed schemes. PMID:25681101

  19. Evaluation of Superimposed Sequence Components of Currents based Islanding Detection Scheme during DG Interconnections

    NASA Astrophysics Data System (ADS)

    Sareen, Karan; Bhalja, Bhavesh R.; Maheshwari, Rudra Prakash

    2016-02-01

    A new islanding detection scheme for distribution network containing different types of distributed generations (DGs) is presented in this paper. The proposed scheme is based on acquiring three phase current samples for full cycle duration of each simulation case of islanding/non-islanding conditions at the point of common coupling (PCC) of the targeted DG. Afterwards, superimposed positive & negative sequence components of current are calculated and continuously compared with pre-determined threshold values. Performance of the proposed scheme has been evaluated on diversified islanding and non-islanding events which were generated by modeling standard IEEE 34-bus system using PSCAD/EMTDC software package. The proposed scheme is capable to detect islanding condition rapidly even for perfect power balance situation for both synchronous and inverter based DGs. Furthermore, it remains stable during non-islanding events such as tripping of multiple DGs and different DG interconnection operating conditions. Therefore, the proposed scheme avoids nuisance tripping during diversified non-islanding events. At the end, comparison of the proposed scheme with the existing scheme clearly indicates its advantage over the existing scheme.

  20. A Target Coverage Scheduling Scheme Based on Genetic Algorithms in Directional Sensor Networks

    PubMed Central

    Gil, Joon-Min; Han, Youn-Hee

    2011-01-01

    As a promising tool for monitoring the physical world, directional sensor networks (DSNs) consisting of a large number of directional sensors are attracting increasing attention. As directional sensors in DSNs have limited battery power and restricted angles of sensing range, maximizing the network lifetime while monitoring all the targets in a given area remains a challenge. A major technique to conserve the energy of directional sensors is to use a node wake-up scheduling protocol by which some sensors remain active to provide sensing services, while the others are inactive to conserve their energy. In this paper, we first address a Maximum Set Covers for DSNs (MSCD) problem, which is known to be NP-complete, and present a greedy algorithm-based target coverage scheduling scheme that can solve this problem by heuristics. This scheme is used as a baseline for comparison. We then propose a target coverage scheduling scheme based on a genetic algorithm that can find the optimal cover sets to extend the network lifetime while monitoring all targets by the evolutionary global search technique. To verify and evaluate these schemes, we conducted simulations and showed that the schemes can contribute to extending the network lifetime. Simulation results indicated that the genetic algorithm-based scheduling scheme had better performance than the greedy algorithm-based scheme in terms of maximizing network lifetime. PMID:22319387

  1. An encryption scheme based on phase-shifting digital holography and amplitude-phase disturbance

    NASA Astrophysics Data System (ADS)

    Hua, Li-Li; Xu, Ning; Yang, Geng

    2014-06-01

    In this paper, we propose an encryption scheme based on phase-shifting digital interferometry. According to the original system framework, we add a random amplitude mask and replace the Fourier transform by the Fresnel transform. We develop a mathematical model and give a discrete formula based on the scheme, which makes it easy to implement the scheme in computer programming. The experimental results show that the improved system has a better performance in security than the original encryption method. Moreover, it demonstrates a good capability of anti-noise and anti-shear robustness.

  2. FIELD TESTS OF GEOGRAPHICALLY-DEPENDENT VS. THRESHOLD-BASED WATERSHED CLASSIFICATION SCHEMED IN THE GREAT LAKES BASIN

    EPA Science Inventory

    We compared classification schemes based on watershed storage (wetland + lake area/watershed area) and forest fragmentation with a geographically-based classification scheme for two case studies involving 1)Lake Superior tributaries and 2) watersheds of riverine coastal wetlands ...

  3. FIELD TESTS OF GEOGRAPHICALLY-DEPENDENT VS. THRESHOLD-BASED WATERSHED CLASSIFICATION SCHEMES IN THE GREAT LAKES BASIN

    EPA Science Inventory

    We compared classification schemes based on watershed storage (wetland + lake area/watershed area) and forest fragmentation with a geographically-based classification scheme for two case studies involving 1) Lake Superior tributaries and 2) watersheds of riverine coastal wetlands...

  4. A solution scheme for the Euler equations based on a multi-dimensional wave model

    NASA Technical Reports Server (NTRS)

    Powell, Kenneth G.; Barth, Timothy J.; Parpia, Ijaz H.

    1993-01-01

    A scheme for the solution of scalar advection on an unstructured mesh has been developed, tested, and extended to the Euler equations. The scheme preserves a linear function exactly, and yields nearly monotone results. The flux function associated with the Euler scheme is based on a discrete 'wave model' for the system of equations. The wave model decomposes the solution gradient at a location into shear waves, entropy waves and acoustic waves and calculates the speeds, strengths and directions associated with the waves. The approach differs from typical flux-difference splitting schemes in that the waves are not assumed to propagate normal to the faces of the control volumes; directions of propagation of the waves are instead computed from solution-gradient information. Results are shown for three test cases, and two different wave models. The results are compared to those from other approaches, including MUSCL and Galerkin least squares schemes.

  5. Effect of control sampling rates on model-based manipulator control schemes

    NASA Technical Reports Server (NTRS)

    Khosla, P. K.

    1987-01-01

    The effect of changing the control sampling period on the performance of the computed-torque and independent joint control schemes is discussed. While the former utilizes the complete dynamics model of the manipulator, the latter assumes a decoupled and linear model of the manipulator dynamics. Researchers discuss the design of controller gains for both the computed-torque and the independent joint control schemes and establish a framework for comparing their trajectory tracking performance. Experiments show that within each scheme the trajectory tracking accuracy varies slightly with the change of the sampling rate. However, at low sampling rates the computed-torque scheme outperforms the independent joint control scheme. Based on experimental results, researchers also conclusively establish the importance of high sampling rates as they result in an increased stiffness of the system.

  6. Security Analysis of the Unrestricted Identity-Based Aggregate Signature Scheme

    PubMed Central

    Lee, Kwangsu; Lee, Dong Hoon

    2015-01-01

    Aggregate signatures allow anyone to combine different signatures signed by different signers on different messages into a short signature. An ideal aggregate signature scheme is an identity-based aggregate signature (IBAS) scheme that supports full aggregation since it can reduce the total transmitted data by using an identity string as a public key and anyone can freely aggregate different signatures. Constructing a secure IBAS scheme that supports full aggregation in bilinear maps is an important open problem. Recently, Yuan et al. proposed such a scheme and claimed its security in the random oracle model under the computational Diffie-Hellman assumption. In this paper, we show that there is an efficient forgery on their IBAS scheme and that their security proof has a serious flaw. PMID:25993247

  7. Asynchronous error-correcting secure communication scheme based on fractional-order shifting chaotic system

    NASA Astrophysics Data System (ADS)

    Chao, Luo

    2015-11-01

    In this paper, a novel digital secure communication scheme is firstly proposed. Different from the usual secure communication schemes based on chaotic synchronization, the proposed scheme employs asynchronous communication which avoids the weakness of synchronous systems and is susceptible to environmental interference. Moreover, as to the transmission errors and data loss in the process of communication, the proposed scheme has the ability to be error-checking and error-correcting in real time. In order to guarantee security, the fractional-order complex chaotic system with the shifting of order is utilized to modulate the transmitted signal, which has high nonlinearity and complexity in both frequency and time domains. The corresponding numerical simulations demonstrate the effectiveness and feasibility of the scheme.

  8. Performance-based workload assessment: Allocation strategy and added task sensitivity

    NASA Technical Reports Server (NTRS)

    Vidulich, Michael A.

    1990-01-01

    The preliminary results of a research program investigating the use of added tasks to evaluate mental workload are reviewed. The focus of the first studies was a reappraisal of the traditional secondary task logic that encouraged the use of low-priority instructions for the added task. It was believed that such low-priority tasks would encourage subjects to split their available resources among the two tasks. The primary task would be assigned all the resources it needed, and any remaining reserve capacity would be assigned to the secondary task. If the model were correct, this approach was expected to combine sensitivity to primary task difficulty with unintrusiveness to primary task performance. The first studies of the current project demonstrated that a high-priority added task, although intrusive, could be more sensitive than the traditional low-priority secondary task. These results suggested that a more appropriate model of the attentional effects associated with added task performance might be based on capacity switching, rather than the traditional optimal allocation model.

  9. Integrated visual vocabulary in latent Dirichlet allocation-based scene classification for IKONOS image

    NASA Astrophysics Data System (ADS)

    Kusumaningrum, Retno; Wei, Hong; Manurung, Ruli; Murni, Aniati

    2014-01-01

    Scene classification based on latent Dirichlet allocation (LDA) is a more general modeling method known as a bag of visual words, in which the construction of a visual vocabulary is a crucial quantization process to ensure success of the classification. A framework is developed using the following new aspects: Gaussian mixture clustering for the quantization process, the use of an integrated visual vocabulary (IVV), which is built as the union of all centroids obtained from the separate quantization process of each class, and the usage of some features, including edge orientation histogram, CIELab color moments, and gray-level co-occurrence matrix (GLCM). The experiments are conducted on IKONOS images with six semantic classes (tree, grassland, residential, commercial/industrial, road, and water). The results show that the use of an IVV increases the overall accuracy (OA) by 11 to 12% and 6% when it is implemented on the selected and all features, respectively. The selected features of CIELab color moments and GLCM provide a better OA than the implementation over CIELab color moment or GLCM as individuals. The latter increases the OA by only ˜2 to 3%. Moreover, the results show that the OA of LDA outperforms the OA of C4.5 and naive Bayes tree by ˜20%.

  10. A Contourlet-Based Embedded Image Coding Scheme on Low Bit-Rate

    NASA Astrophysics Data System (ADS)

    Song, Haohao; Yu, Songyu

    Contourlet transform (CT) is a new image representation method, which can efficiently represent contours and textures in images. However, CT is a kind of overcomplete transform with a redundancy factor of 4/3. If it is applied to image compression straightforwardly, the encoding bit-rate may increase to meet a given distortion. This fact baffles the coding community to develop CT-based image compression techniques with satisfactory performance. In this paper, we analyze the distribution of significant contourlet coefficients in different subbands and propose a new contourlet-based embedded image coding (CEIC) scheme on low bit-rate. The well-known wavelet-based embedded image coding (WEIC) algorithms such as EZW, SPIHT and SPECK can be easily integrated into the proposed scheme by constructing a virtual low frequency subband, modifying the coding framework of WEIC algorithms according to the structure of contourlet coefficients, and adopting a high-efficiency significant coefficient scanning scheme for CEIC scheme. The proposed CEIC scheme can provide an embedded bit-stream, which is desirable in heterogeneous networks. Our experiments demonstrate that the proposed scheme can achieve the better compression performance on low bit-rate. Furthermore, thanks to the contourlet adopted in the proposed scheme, more contours and textures in the coded images are preserved to ensure the superior subjective quality.

  11. A Multistep, Consensus-Based Approach to Organ Allocation in Liver Transplantation: Toward a "Blended Principle Model".

    PubMed

    Cillo, U; Burra, P; Mazzaferro, V; Belli, L; Pinna, A D; Spada, M; Nanni Costa, A; Toniutto, P

    2015-10-01

    Since Italian liver allocation policy was last revised (in 2012), relevant critical issues and conceptual advances have emerged, calling for significant improvements. We report the results of a national consensus conference process, promoted by the Italian College of Liver Transplant Surgeons (for the Italian Society for Organ Transplantation) and the Italian Association for the Study of the Liver, to review the best indicators for orienting organ allocation policies based on principles of urgency, utility, and transplant benefit in the light of current scientific evidence. MELD exceptions and hepatocellular carcinoma were analyzed to construct a transplantation priority algorithm, given the inequity of a purely MELD-based system for governing organ allocation. Working groups of transplant surgeons and hepatologists prepared a list of statements for each topic, scoring their quality of evidence and strength of recommendation using the Centers for Disease Control grading system. A jury of Italian transplant surgeons, hepatologists, intensivists, infectious disease specialists, epidemiologists, representatives of patients' associations and organ-sharing organizations, transplant coordinators, and ethicists voted on and validated the proposed statements. After carefully reviewing the statements, a critical proposal for revising Italy's current liver allocation policy was prepared jointly by transplant surgeons and hepatologists. PMID:26274338

  12. IP Packet Size Entropy-Based Scheme for Detection of DoS/DDoS Attacks

    NASA Astrophysics Data System (ADS)

    Du, Ping; Abe, Shunji

    Denial of service (DoS) attacks have become one of the most serious threats to the Internet. Enabling detection of attacks in network traffic is an important and challenging task. However, most existing volume-based schemes can not detect short-term attacks that have a minor effect on traffic volume. On the other hand, feature-based schemes are not suitable for real-time detection because of their complicated calculations. In this paper, we develop an IP packet size entropy (IPSE)-based DoS/DDoS detection scheme in which the entropy is markedly changed when traffic is affected by an attack. Through our analysis, we find that the IPSE-based scheme is capable of detecting not only long-term attacks but also short-term attacks that are beyond the volume-based schemes' ability to detect. Moreover, we test our proposal using two typical Internet traffic data sets from DARPA and SINET, and the test results show that the IPSE-based detection scheme can provide detection of DoS/DDoS attacks not only in a local area network (DARPA) and but also in academic backbone network (SINET).

  13. Robust ECC-based authenticated key agreement scheme with privacy protection for Telecare medicine information systems.

    PubMed

    Zhang, Liping; Zhu, Shaohui

    2015-05-01

    To protect the transmission of the sensitive medical data, a secure and efficient authenticated key agreement scheme should be deployed when the healthcare delivery session is established via Telecare Medicine Information Systems (TMIS) over the unsecure public network. Recently, Islam and Khan proposed an authenticated key agreement scheme using elliptic curve cryptography for TMIS. They claimed that their proposed scheme is provably secure against various attacks in random oracle model and enjoys some good properties such as user anonymity. In this paper, however, we point out that any legal but malicious patient can reveal other user's identity. Consequently, their scheme suffers from server spoofing attack and off-line password guessing attack. Moreover, if the malicious patient performs the same time of the registration as other users, she can further launch the impersonation attack, man-in-the-middle attack, modification attack, replay attack, and strong replay attack successfully. To eliminate these weaknesses, we propose an improved ECC-based authenticated key agreement scheme. Security analysis demonstrates that the proposed scheme can resist various attacks and enables the patient to enjoy the remote healthcare services with privacy protection. Through the performance evaluation, we show that the proposed scheme achieves a desired balance between security and performance in comparisons with other related schemes. PMID:25732081

  14. 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. PMID:22673892

  15. Testing conceptual and physically based soil hydrology schemes against observations for the Amazon Basin

    NASA Astrophysics Data System (ADS)

    Guimberteau, M.; Ducharne, A.; Ciais, P.; Boisier, J. P.; Peng, S.; De Weirdt, M.; Verbeeck, H.

    2014-06-01

    This study analyzes the performance of the two soil hydrology schemes of the land surface model ORCHIDEE in estimating Amazonian hydrology and phenology for five major sub-basins (Xingu, Tapajós, Madeira, Solimões and Negro), during the 29-year period 1980-2008. A simple 2-layer scheme with a bucket topped by an evaporative layer is compared to an 11-layer diffusion scheme. The soil schemes are coupled with a river routing module and a process model of plant physiology, phenology and carbon dynamics. The simulated water budget and vegetation functioning components are compared with several data sets at sub-basin scale. The use of the 11-layer soil diffusion scheme does not significantly change the Amazonian water budget simulation when compared to the 2-layer soil scheme (+3.1 and -3.0% in evapotranspiration and river discharge, respectively). However, the higher water-holding capacity of the soil and the physically based representation of runoff and drainage in the 11-layer soil diffusion scheme result in more dynamic soil water storage variation and improved simulation of the total terrestrial water storage when compared to GRACE satellite estimates. The greater soil water storage within the 11-layer scheme also results in increased dry-season evapotranspiration (+0.5 mm d-1, +17%) and improves river discharge simulation in the southeastern sub-basins such as the Xingu. Evapotranspiration over this sub-basin is sustained during the whole dry season with the 11-layer soil diffusion scheme, whereas the 2-layer scheme limits it after only 2 dry months. Lower plant drought stress simulated by the 11-layer soil diffusion scheme leads to better simulation of the seasonal cycle of photosynthesis (GPP) when compared to a GPP data-driven model based on eddy covariance and satellite greenness measurements. A dry-season length between 4 and 7 months over the entire Amazon Basin is found to be critical in distinguishing differences in hydrological feedbacks between the

  16. Efficient Nash Equilibrium Resource Allocation Based on Game Theory Mechanism in Cloud Computing by Using Auction

    PubMed Central

    Nezarat, Amin; Dastghaibifard, GH

    2015-01-01

    One of the most complex issues in the cloud computing environment is the problem of resource allocation so that, on one hand, the cloud provider expects the most profitability and, on the other hand, users also expect to have the best resources at their disposal considering the budget constraints and time. In most previous work conducted, heuristic and evolutionary approaches have been used to solve this problem. Nevertheless, since the nature of this environment is based on economic methods, using such methods can decrease response time and reducing the complexity of the problem. In this paper, an auction-based method is proposed which determines the auction winner by applying game theory mechanism and holding a repetitive game with incomplete information in a non-cooperative environment. In this method, users calculate suitable price bid with their objective function during several round and repetitions and send it to the auctioneer; and the auctioneer chooses the winning player based the suggested utility function. In the proposed method, the end point of the game is the Nash equilibrium point where players are no longer inclined to alter their bid for that resource and the final bid also satisfies the auctioneer’s utility function. To prove the response space convexity, the Lagrange method is used and the proposed model is simulated in the cloudsim and the results are compared with previous work. At the end, it is concluded that this method converges to a response in a shorter time, provides the lowest service level agreement violations and the most utility to the provider. PMID:26431035

  17. Efficient Nash Equilibrium Resource Allocation Based on Game Theory Mechanism in Cloud Computing by Using Auction.

    PubMed

    Nezarat, Amin; Dastghaibifard, G H

    2015-01-01

    One of the most complex issues in the cloud computing environment is the problem of resource allocation so that, on one hand, the cloud provider expects the most profitability and, on the other hand, users also expect to have the best resources at their disposal considering the budget constraints and time. In most previous work conducted, heuristic and evolutionary approaches have been used to solve this problem. Nevertheless, since the nature of this environment is based on economic methods, using such methods can decrease response time and reducing the complexity of the problem. In this paper, an auction-based method is proposed which determines the auction winner by applying game theory mechanism and holding a repetitive game with incomplete information in a non-cooperative environment. In this method, users calculate suitable price bid with their objective function during several round and repetitions and send it to the auctioneer; and the auctioneer chooses the winning player based the suggested utility function. In the proposed method, the end point of the game is the Nash equilibrium point where players are no longer inclined to alter their bid for that resource and the final bid also satisfies the auctioneer's utility function. To prove the response space convexity, the Lagrange method is used and the proposed model is simulated in the cloudsim and the results are compared with previous work. At the end, it is concluded that this method converges to a response in a shorter time, provides the lowest service level agreement violations and the most utility to the provider. PMID:26431035

  18. Twin-Schnorr: a security upgrade for the Schnorr identity-based identification scheme.

    PubMed

    Chin, Ji-Jian; Tan, Syh-Yuan; Heng, Swee-Huay; Phan, Raphael Chung-Wei

    2015-01-01

    Most identity-based identification (IBI) schemes proposed in recent literature are built using pairing operations. This decreases efficiency due to the high operation costs of pairings. Furthermore, most of these IBI schemes are proven to be secure against impersonation under active and concurrent attacks using interactive assumptions such as the one-more RSA inversion assumption or the one-more discrete logarithm assumption, translating to weaker security guarantees due to the interactive nature of these assumptions. The Schnorr-IBI scheme was first proposed through the Kurosawa-Heng transformation from the Schnorr signature. It remains one of the fastest yet most secure IBI schemes under impersonation against passive attacks due to its pairing-free design. However, when required to be secure against impersonators under active and concurrent attacks, it deteriorates greatly in terms of efficiency due to the protocol having to be repeated multiple times. In this paper, we upgrade the Schnorr-IBI scheme to be secure against impersonation under active and concurrent attacks using only the classical discrete logarithm assumption. This translates to a higher degree of security guarantee with only some minor increments in operational costs. Furthermore, because the scheme operates without pairings, it still retains its efficiency and superiority when compared to other pairing-based IBI schemes. PMID:25692179

  19. Novel neural networks-based fault tolerant control scheme with fault alarm.

    PubMed

    Shen, Qikun; Jiang, Bin; Shi, Peng; Lim, Cheng-Chew

    2014-11-01

    In this paper, the problem of adaptive active fault-tolerant control for a class of nonlinear systems with unknown actuator fault is investigated. The actuator fault is assumed to have no traditional affine appearance of the system state variables and control input. The useful property of the basis function of the radial basis function neural network (NN), which will be used in the design of the fault tolerant controller, is explored. Based on the analysis of the design of normal and passive fault tolerant controllers, by using the implicit function theorem, a novel NN-based active fault-tolerant control scheme with fault alarm is proposed. Comparing with results in the literature, the fault-tolerant control scheme can minimize the time delay between fault occurrence and accommodation that is called the time delay due to fault diagnosis, and reduce the adverse effect on system performance. In addition, the FTC scheme has the advantages of a passive fault-tolerant control scheme as well as the traditional active fault-tolerant control scheme's properties. Furthermore, the fault-tolerant control scheme requires no additional fault detection and isolation model which is necessary in the traditional active fault-tolerant control scheme. Finally, simulation results are presented to demonstrate the efficiency of the developed techniques. PMID:25014982

  20. On the security flaws in ID-based password authentication schemes for telecare medical information systems.

    PubMed

    Mishra, Dheerendra

    2015-01-01

    Telecare medical information systems (TMIS) enable healthcare delivery services. However, access of these services via public channel raises security and privacy issues. In recent years, several smart card based authentication schemes have been introduced to ensure secure and authorized communication between remote entities over the public channel for the (TMIS). We analyze the security of some of the recently proposed authentication schemes of Lin, Xie et al., Cao and Zhai, and Wu and Xu's for TMIS. Unfortunately, we identify that these schemes failed to satisfy desirable security attributes. In this article we briefly discuss four dynamic ID-based authentication schemes and demonstrate their failure to satisfy desirable security attributes. The study is aimed to demonstrate how inefficient password change phase can lead to denial of server scenario for an authorized user, and how an inefficient login phase causes the communication and computational overhead and decrease the performance of the system. Moreover, we show the vulnerability of Cao and Zhai's scheme to known session specific temporary information attack, vulnerability of Wu and Xu's scheme to off-line password guessing attack, and vulnerability of Xie et al.'s scheme to untraceable on-line password guessing attack. PMID:25486891

  1. Twin-Schnorr: A Security Upgrade for the Schnorr Identity-Based Identification Scheme

    PubMed Central

    Heng, Swee-Huay; Phan, Raphael Chung-Wei

    2015-01-01

    Most identity-based identification (IBI) schemes proposed in recent literature are built using pairing operations. This decreases efficiency due to the high operation costs of pairings. Furthermore, most of these IBI schemes are proven to be secure against impersonation under active and concurrent attacks using interactive assumptions such as the one-more RSA inversion assumption or the one-more discrete logarithm assumption, translating to weaker security guarantees due to the interactive nature of these assumptions. The Schnorr-IBI scheme was first proposed through the Kurosawa-Heng transformation from the Schnorr signature. It remains one of the fastest yet most secure IBI schemes under impersonation against passive attacks due to its pairing-free design. However, when required to be secure against impersonators under active and concurrent attacks, it deteriorates greatly in terms of efficiency due to the protocol having to be repeated multiple times. In this paper, we upgrade the Schnorr-IBI scheme to be secure against impersonation under active and concurrent attacks using only the classical discrete logarithm assumption. This translates to a higher degree of security guarantee with only some minor increments in operational costs. Furthermore, because the scheme operates without pairings, it still retains its efficiency and superiority when compared to other pairing-based IBI schemes. PMID:25692179

  2. Allocation of environmental loads in recycling: a model based in the qualitative value of recycled material

    NASA Astrophysics Data System (ADS)

    Ferreira, Jose V. R.; Domingos, Idalina; Antunes, Paula

    2001-02-01

    When the life cycle of a product, material or service, studied in a Life Cycle Assessment (LCA) affect other life cycles not included in the system in analysis, it is necessary to apply allocation rules. Allocation can be defined, in LCA context, as the act of assigning the environmental loads of a system to the functions of that system in proportionate shares. Most of the available allocation methods are of generic application, they do not take into account the quality of the materials to be recycled and the few that do take it into account attribute to it a quantitative value. Methods that are both generic and scientifically correct are generally difficult to apply. Rules that are too simple for a case by case application could lead to studies of life cycle assessment that cannot be compared. This way, the best will be to dispose of simple methods but just and mathematically correct with a fundamentally driven application to a sector of economic activity. In this study a method of allocation is proposed which takes into account primarily the "qualitative" value of the material to be recycled, irrespective of being a pos-consumption product/material or a secondary material of a production process. Through a case study, the potential of application of the proposed method is demonstrated, in the recycling of products coming from wood industries and its derivatives, when compared with other allocation methods.

  3. Wood adhesion cell segmentation scheme based on GVF-Snake model

    NASA Astrophysics Data System (ADS)

    Zhao, Lei; Ma, Yan

    2010-08-01

    In order to extract the characteristic parameters of the wood cells accurately, this paper presents an efficient scheme for wood cell segmentation. This scheme is mainly based on GVF-Snake model and the method of image thinning. Firstly, computing the Category Roundness of every connectivity domain is done in order to get the degree of adhesion. Secondly, image thinning helps to get the skeleton of the cell. Finally, according to the location coordinates of skeleton and contour, it can determine the location of segmentation. Experimental results demonstrate the scheme for precise extraction with limited human intervention; it can also determine the correct edge of segmentation. Comparatively speaking, the inaccuracy is rather limited.

  4. An image encryption scheme based on the MLNCML system using DNA sequences

    NASA Astrophysics Data System (ADS)

    Zhang, Ying-Qian; Wang, Xing-Yuan; Liu, Jia; Chi, Ze-Lin

    2016-07-01

    We propose a new image scheme based on the spatiotemporal chaos of the Mixed Linear-Nonlinear Coupled Map Lattices (MLNCML). This spatiotemporal chaotic system has more cryptographic features in dynamics than the system of Coupled Map Lattices (CML). In the proposed scheme, we employ the strategy of DNA computing and one time pad encryption policy, which can enhance the sensitivity to the plaintext and resist differential attack, brute-force attack, statistical attack and plaintext attack. Simulation results and theoretical analysis indicate that the proposed scheme has superior high security.

  5. Restoration scheme for multi-failures based on protection ring with dynamic weight in WDM networks

    NASA Astrophysics Data System (ADS)

    Huang, Hai; Zhao, Yongli; Zhang, Jie; Wang, Dajiang; Gu, Wanyi

    2011-12-01

    A novel restoration scheme for multi-failures based on protection ring with dynamic weight (PRDW) is proposed in this paper. This scheme effectively resolves the multi-failures which is in one service and the conflicts by restoration between services. PRDW use Dijkstra's algorithm to compute path and protection ring. These rings rely on protection weight which is dynamic, so that they can as much as possible to divide multi-failures to single ones. Meanwhile PRDW introduce independent protection weight to balance load, which effectively gets combat for resources less vicious. Simulation results show that PRDW works better than traditional schemes.

  6. A fingerprint encryption scheme based on irreversible function and secure authentication.

    PubMed

    Yang, Yijun; Yu, Jianping; Zhang, Peng; Wang, Shulan

    2015-01-01

    A fingerprint encryption scheme based on irreversible function has been designed in this paper. Since the fingerprint template includes almost the entire information of users' fingerprints, the personal authentication can be determined only by the fingerprint features. This paper proposes an irreversible transforming function (using the improved SHA1 algorithm) to transform the original minutiae which are extracted from the thinned fingerprint image. Then, Chinese remainder theorem is used to obtain the biokey from the integration of the transformed minutiae and the private key. The result shows that the scheme has better performance on security and efficiency comparing with other irreversible function schemes. PMID:25873989

  7. A Fingerprint Encryption Scheme Based on Irreversible Function and Secure Authentication

    PubMed Central

    Yu, Jianping; Zhang, Peng; Wang, Shulan

    2015-01-01

    A fingerprint encryption scheme based on irreversible function has been designed in this paper. Since the fingerprint template includes almost the entire information of users' fingerprints, the personal authentication can be determined only by the fingerprint features. This paper proposes an irreversible transforming function (using the improved SHA1 algorithm) to transform the original minutiae which are extracted from the thinned fingerprint image. Then, Chinese remainder theorem is used to obtain the biokey from the integration of the transformed minutiae and the private key. The result shows that the scheme has better performance on security and efficiency comparing with other irreversible function schemes. PMID:25873989

  8. Stackelberg Game Based Power Allocation for Physical Layer Security of Device-to-device Communication Underlaying Cellular Networks

    NASA Astrophysics Data System (ADS)

    Qu, Junyue; Cai, Yueming; Wu, Dan; Chen, Hualiang

    2014-05-01

    The problem of power allocation for device-to-device (D2D) underlay communication to improve physical layer security is addressed. Specifically, to improve the secure communication of the cellular users, we introduce a Stackelberg game for allocating the power of the D2D link under a total power constraint and a rate constraint at the D2D pair. In the introduced Stackelberg game the D2D pair works as a seller and the cellular UEs work as buyers. Firstly, because the interference signals from D2D pair are unknown to both the legitimate receiver and the illegitimate eavesdropper, it is possible that a cellular UE decline to participate in the introduced Stackelberg game. So the condition under which a legitimate user will participate in the introduced Stackelberg game is discussed. Then, based on the Stackelberg game, we propose a semi-distributed power allocation algorithm, which is proved to conclude after finite-time iterations. In the end, some simulations are presented to verify the performance improvement in the physical layer security of cellular UEs using the proposed power allocation algorithm. We can determine that with the proposed algorithm, while the D2D pair's communication demand is met, the physical layer security of cellular UEs can be improved.

  9. A stereoscopic video conversion scheme based on spatio-temporal analysis of MPEG videos

    NASA Astrophysics Data System (ADS)

    Lin, Guo-Shiang; Huang, Hsiang-Yun; Chen, Wei-Chih; Yeh, Cheng-Ying; Liu, Kai-Che; Lie, Wen-Nung

    2012-12-01

    In this article, an automatic stereoscopic video conversion scheme which accepts MPEG-encoded videos as input is proposed. Our scheme is depth-based, relying on spatio-temporal analysis of the decoded video data to yield depth perception cues, such as temporal motion and spatial contrast, which reflect the relative depths between the foreground and the background areas. Our scheme is shot-adaptive, demanding that shot change detection and shot classification be performed for tuning of algorithm or parameters that are used for depth cue combination. The above-mentioned depth estimation is initially block-based, followed by a locally adaptive joint trilateral upsampling algorithm to reduce the computing load significantly. A recursive temporal filter is used to reduce the possible depth fluctuations (and also artifacts in the synthesized images) resulting from wrong depth estimations. The traditional Depth-Image-Based-Rendering algorithm is used to synthesize the left- and right-view frames for 3D display. Subjective tests show that videos converted by our scheme provide comparable perceived depth and visual quality with those converted from the depth data calculated by stereo vision techniques. Also, our scheme is shown to outperform the well-known TriDef software in terms of human's perceived 3D depth. Based on the implementation by using "OpenMP" parallel programming model, our scheme is capable of executing in real-time on a multi-core CPU platform.

  10. A GeneralizedWeight-Based Particle-In-Cell Simulation Scheme

    SciTech Connect

    W.W. Lee, T.G. Jenkins and S. Ethier

    2010-02-02

    A generalized weight-based particle simulation scheme suitable for simulating magnetized plasmas, where the zeroth-order inhomogeneity is important, is presented. The scheme is an extension of the perturbative simulation schemes developed earlier for particle-in-cell (PIC) simulations. The new scheme is designed to simulate both the perturbed distribution (δf) and the full distribution (full-F) within the same code. The development is based on the concept of multiscale expansion, which separates the scale lengths of the background inhomogeneity from those associated with the perturbed distributions. The potential advantage for such an arrangement is to minimize the particle noise by using δf in the linear stage stage of the simulation, while retaining the flexibility of a full-F capability in the fully nonlinear stage of the development when signals associated with plasma turbulence are at a much higher level than those from the intrinsic particle noise.

  11. Feedback control scheme of traffic jams based on the coupled map car-following model

    NASA Astrophysics Data System (ADS)

    Zhou, Tong; Sun, Di-Hua; Zhao, Min; Li, Hua-Min

    2013-09-01

    Based on the pioneering work of Konishi et al. [Phys. Rev. E (1999) 60 4000], a new feedback control scheme is presented to suppress traffic jams based on the coupled map car-following model under the open boundary condition. The effect of the safe headway on the traffic system is considered. According to the control theory, the condition under which traffic jams can be suppressed is analyzed. The results are compared with the previous results concerning congestion control. The simulations show that the suppression performance of our scheme on traffic jams is better than those of the previous schemes, although all the schemes can suppress traffic jams. The simulation results are consistent with theoretical analyses.

  12. Cryptanalysis and improvement of Yan et al.'s biometric-based authentication scheme for telecare medicine information systems.

    PubMed

    Mishra, Dheerendra; Mukhopadhyay, Sourav; Chaturvedi, Ankita; Kumari, Saru; Khan, Muhammad Khurram

    2014-06-01

    Remote user authentication is desirable for a Telecare Medicine Information System (TMIS) for the safety, security and integrity of transmitted data over the public channel. In 2013, Tan presented a biometric based remote user authentication scheme and claimed that his scheme is secure. Recently, Yan et al. demonstrated some drawbacks in Tan's scheme and proposed an improved scheme to erase the drawbacks of Tan's scheme. We analyze Yan et al.'s scheme and identify that their scheme is vulnerable to off-line password guessing attack, and does not protect anonymity. Moreover, in their scheme, login and password change phases are inefficient to identify the correctness of input where inefficiency in password change phase can cause denial of service attack. Further, we design an improved scheme for TMIS with the aim to eliminate the drawbacks of Yan et al.'s scheme. PMID:24880932

  13. Proxy-Based IPv6 Neighbor Discovery Scheme for Wireless LAN Based Mesh Networks

    NASA Astrophysics Data System (ADS)

    Lee, Jihoon; Jeon, Seungwoo; Kim, Jaehoon

    Multi-hop Wireless LAN-based mesh network (WMN) provides high capacity and self-configuring capabilities. Due to data forwarding and path selection based on MAC address, WMN requires additional operations to achieve global connectivity using IPv6 address. The neighbor discovery operation over WLAN mesh networks requires repeated all-node broadcasting and this gives rise to a big burden in the entire mesh networks. In this letter, we propose the proxy neighbor discovery scheme for optimized IPv6 communication over WMN to reduce network overhead and communication latency. Using simulation experiments, we show that the control overhead and communication setup latency can be significantly reduced using the proxy-based neighbor discovery mechanism.

  14. Cache Scheme Based on Pre-Fetch Operation in ICN

    PubMed Central

    Duan, Jie; Wang, Xiong; Xu, Shizhong; Liu, Yuanni; Xu, Chuan; Zhao, Guofeng

    2016-01-01

    Many recent researches focus on ICN (Information-Centric Network), in which named content becomes the first citizen instead of end-host. In ICN, Named content can be further divided into many small sized chunks, and chunk-based communication has merits over content-based communication. The universal in-network cache is one of the fundamental infrastructures for ICN. In this work, a chunk-level cache mechanism based on pre-fetch operation is proposed. The main idea is that, routers with cache store should pre-fetch and cache the next chunks which may be accessed in the near future according to received requests and cache policy for reducing the users’ perceived latency. Two pre-fetch driven modes are present to answer when and how to pre-fetch. The LRU (Least Recently Used) is employed for the cache replacement. Simulation results show that the average user perceived latency and hops can be decreased by employed this cache mechanism based on pre-fetch operation. Furthermore, we also demonstrate that the results are influenced by many factors, such as the cache capacity, Zipf parameters and pre-fetch window size. PMID:27362478

  15. Security analysis of a chaotic map-based authentication scheme for telecare medicine information systems.

    PubMed

    Yau, Wei-Chuen; Phan, Raphael C-W

    2013-12-01

    Many authentication schemes have been proposed for telecare medicine information systems (TMIS) to ensure the privacy, integrity, and availability of patient records. These schemes are crucial for TMIS systems because otherwise patients' medical records become susceptible to tampering thus hampering diagnosis or private medical conditions of patients could be disclosed to parties who do not have a right to access such information. Very recently, Hao et al. proposed a chaotic map-based authentication scheme for telecare medicine information systems in a recent issue of Journal of Medical Systems. They claimed that the authentication scheme can withstand various attacks and it is secure to be used in TMIS. In this paper, we show that this authentication scheme is vulnerable to key-compromise impersonation attacks, off-line password guessing attacks upon compromising of a smart card, and parallel session attacks. We also exploit weaknesses in the password change phase of the scheme to mount a denial-of-service attack. Our results show that this scheme cannot be used to provide security in a telecare medicine information system. PMID:24194093

  16. Bernoulli-based random undersampling schemes for 2D seismic data regularization

    NASA Astrophysics Data System (ADS)

    Cai, Rui; Zhao, Qun; She, De-Ping; Yang, Li; Cao, Hui; Yang, Qin-Yong

    2014-09-01

    Seismic data regularization is an important preprocessing step in seismic signal processing. Traditional seismic acquisition methods follow the Shannon-Nyquist sampling theorem, whereas compressive sensing (CS) provides a fundamentally new paradigm to overcome limitations in data acquisition. Besides the sparse representation of seismic signal in some transform domain and the 1-norm reconstruction algorithm, the seismic data regularization quality of CS-based techniques strongly depends on random undersampling schemes. For 2D seismic data, discrete uniform-based methods have been investigated, where some seismic traces are randomly sampled with an equal probability. However, in theory and practice, some seismic traces with different probability are required to be sampled for satisfying the assumptions in CS. Therefore, designing new undersampling schemes is imperative. We propose a Bernoulli-based random undersampling scheme and its jittered version to determine the regular traces that are randomly sampled with different probability, while both schemes comply with the Bernoulli process distribution. We performed experiments using the Fourier and curvelet transforms and the spectral projected gradient reconstruction algorithm for 1-norm (SPGL1), and ten different random seeds. According to the signal-to-noise ratio (SNR) between the original and reconstructed seismic data, the detailed experimental results from 2D numerical and physical simulation data show that the proposed novel schemes perform overall better than the discrete uniform schemes.

  17. Password-based authenticated key exchange scheme using smart card

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Zhong, Shaojun

    2013-03-01

    A protocol that allows any two entities to negotiate a shared session key is commonly called a key exchange protocol. If the protocol provides a function to authenticate each other, we call the protocol authenticated key exchange protocol (AKE). Password authentication key exchange (PAKE) is the AKE protocol in which the two entities share a humanmemorable password. Most of current PAKE relies on the existence of a public key infrastructure, which sometime is impossible for a certain environments such as low computational device due to the computation overhead. In this paper, we propose password-based authenticated key exchange using smart card. Compared to previous PAKE, our protocol is more efficient because our protocol is based on ECC. Thereby, the proposed protocol can be well applied to low computation device.

  18. A novel interacting multiple model based network intrusion detection scheme

    NASA Astrophysics Data System (ADS)

    Xin, Ruichi; Venkatasubramanian, Vijay; Leung, Henry

    2006-04-01

    In today's information age, information and network security are of primary importance to any organization. Network intrusion is a serious threat to security of computers and data networks. In internet protocol (IP) based network, intrusions originate in different kinds of packets/messages contained in the open system interconnection (OSI) layer 3 or higher layers. Network intrusion detection and prevention systems observe the layer 3 packets (or layer 4 to 7 messages) to screen for intrusions and security threats. Signature based methods use a pre-existing database that document intrusion patterns as perceived in the layer 3 to 7 protocol traffics and match the incoming traffic for potential intrusion attacks. Alternately, network traffic data can be modeled and any huge anomaly from the established traffic pattern can be detected as network intrusion. The latter method, also known as anomaly based detection is gaining popularity for its versatility in learning new patterns and discovering new attacks. It is apparent that for a reliable performance, an accurate model of the network data needs to be established. In this paper, we illustrate using collected data that network traffic is seldom stationary. We propose the use of multiple models to accurately represent the traffic data. The improvement in reliability of the proposed model is verified by measuring the detection and false alarm rates on several datasets.

  19. 45 CFR 402.31 - Determination of allocations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... State Allocations § 402.31 Determination of allocations. (a) Allocation formula. Allocations will be computed according to a formula using the following factors and weights: (1) 50 percent based on the...

  20. Scheme for efficient fiber-based CARS probe

    NASA Astrophysics Data System (ADS)

    Balu, Mihaela; Liu, Gangjun; Chen, Zhongping; Tromberg, Bruce J.; Potma, Eric O.

    2010-02-01

    We demonstrate a fiber-based probe for maximum collection of the Coherent anti-Stokes Raman Scattering (CARS) signal in biological tissues. We discuss the design challenges including capturing the back-scattered forward generated CARS signal in the sample and the effects of fiber nonlinearities on the propagating pulses. Three different biological tissues were imaged in vitro in order to assess the performance of our fiberdelivered probe for CARS imaging, a tool which we consider an important advance towards label-free, in vivo probing of superficial tissues.

  1. Protection of Health Imagery by Region Based Lossless Reversible Watermarking Scheme

    PubMed Central

    Priya, R. Lakshmi; Sadasivam, V.

    2015-01-01

    Providing authentication and integrity in medical images is a problem and this work proposes a new blind fragile region based lossless reversible watermarking technique to improve trustworthiness of medical images. The proposed technique embeds the watermark using a reversible least significant bit embedding scheme. The scheme combines hashing, compression, and digital signature techniques to create a content dependent watermark making use of compressed region of interest (ROI) for recovery of ROI as reported in literature. The experiments were carried out to prove the performance of the scheme and its assessment reveals that ROI is extracted in an intact manner and PSNR values obtained lead to realization that the presented scheme offers greater protection for health imageries. PMID:26649328

  2. On the security of a dynamic ID-based authentication scheme for telecare medical information systems.

    PubMed

    Lin, Han-Yu

    2013-04-01

    Telecare medical information systems (TMISs) are increasingly popular technologies for healthcare applications. Using TMISs, physicians and caregivers can monitor the vital signs of patients remotely. Since the database of TMISs stores patients' electronic medical records (EMRs), only authorized users should be granted the access to this information for the privacy concern. To keep the user anonymity, recently, Chen et al. proposed a dynamic ID-based authentication scheme for telecare medical information system. They claimed that their scheme is more secure and robust for use in a TMIS. However, we will demonstrate that their scheme fails to satisfy the user anonymity due to the dictionary attacks. It is also possible to derive a user password in case of smart card loss attacks. Additionally, an improved scheme eliminating these weaknesses is also presented. PMID:23345092

  3. Improvement of a quantum broadcasting multiple blind signature scheme based on quantum teleportation

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Qiu, Daowen; Zou, Xiangfu

    2016-06-01

    Recently, a broadcasting multiple blind signature scheme based on quantum teleportation has been proposed for the first time. It is claimed to have unconditional security and properties of quantum multiple signature and quantum blind signature. In this paper, we analyze the security of the protocol and show that each signatory can learn the signed message by a single-particle measurement and the signed message can be modified at random by any attacker according to the scheme. Furthermore, there are some participant attacks and external attacks existing in the scheme. Finally, we present an improved scheme and show that it can resist all of the mentioned attacks. Additionally, the secret keys can be used again and again, making it more efficient and practical.

  4. Improvement of a quantum broadcasting multiple blind signature scheme based on quantum teleportation

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Qiu, Daowen; Zou, Xiangfu

    2016-03-01

    Recently, a broadcasting multiple blind signature scheme based on quantum teleportation has been proposed for the first time. It is claimed to have unconditional security and properties of quantum multiple signature and quantum blind signature. In this paper, we analyze the security of the protocol and show that each signatory can learn the signed message by a single-particle measurement and the signed message can be modified at random by any attacker according to the scheme. Furthermore, there are some participant attacks and external attacks existing in the scheme. Finally, we present an improved scheme and show that it can resist all of the mentioned attacks. Additionally, the secret keys can be used again and again, making it more efficient and practical.

  5. Evaluation of Effectiveness of Wavelet Based Denoising Schemes Using ANN and SVM for Bearing Condition Classification

    PubMed Central

    G. S., Vijay; H. S., Kumar; Pai P., Srinivasa; N. S., Sriram; Rao, Raj B. K. N.

    2012-01-01

    The wavelet based denoising has proven its ability to denoise the bearing vibration signals by improving the signal-to-noise ratio (SNR) and reducing the root-mean-square error (RMSE). In this paper seven wavelet based denoising schemes have been evaluated based on the performance of the Artificial Neural Network (ANN) and the Support Vector Machine (SVM), for the bearing condition classification. The work consists of two parts, the first part in which a synthetic signal simulating the defective bearing vibration signal with Gaussian noise was subjected to these denoising schemes. The best scheme based on the SNR and the RMSE was identified. In the second part, the vibration signals collected from a customized Rolling Element Bearing (REB) test rig for four bearing conditions were subjected to these denoising schemes. Several time and frequency domain features were extracted from the denoised signals, out of which a few sensitive features were selected using the Fisher's Criterion (FC). Extracted features were used to train and test the ANN and the SVM. The best denoising scheme identified, based on the classification performances of the ANN and the SVM, was found to be the same as the one obtained using the synthetic signal. PMID:23213323

  6. Agenda-Based Regulation of Study-Time Allocation: When Agendas Override Item-Based Monitoring

    ERIC Educational Resources Information Center

    Ariel, Robert; Dunlosky, John; Bailey, Heather

    2009-01-01

    Theories of self-regulated study assume that learners monitor item difficulty when making decisions about which items to select for study. To complement such theories, the authors propose an agenda-based regulation (ABR) model in which learners' study decisions are guided by an agenda that learners develop to prioritize items for study, given…

  7. TripSense: A Trust-Based Vehicular Platoon Crowdsensing Scheme with Privacy Preservation in VANETs.

    PubMed

    Hu, Hao; Lu, Rongxing; Huang, Cheng; Zhang, Zonghua

    2016-01-01

    In this paper, we propose a trust-based vehicular platoon crowdsensing scheme, named TripSense, in VANET. The proposed TripSense scheme introduces a trust-based system to evaluate vehicles' sensing abilities and then selects the more capable vehicles in order to improve sensing results accuracy. In addition, the sensing tasks are accomplished by platoon member vehicles and preprocessed by platoon head vehicles before the data are uploaded to server. Hence, it is less time-consuming and more efficient compared with the way where the data are submitted by individual platoon member vehicles. Hence it is more suitable in ephemeral networks like VANET. Moreover, our proposed TripSense scheme integrates unlinkable pseudo-ID techniques to achieve PM vehicle identity privacy, and employs a privacy-preserving sensing vehicle selection scheme without involving the PM vehicle's trust score to keep its location privacy. Detailed security analysis shows that our proposed TripSense scheme not only achieves desirable privacy requirements but also resists against attacks launched by adversaries. In addition, extensive simulations are conducted to show the correctness and effectiveness of our proposed scheme. PMID:27258287

  8. TripSense: A Trust-Based Vehicular Platoon Crowdsensing Scheme with Privacy Preservation in VANETs

    PubMed Central

    Hu, Hao; Lu, Rongxing; Huang, Cheng; Zhang, Zonghua

    2016-01-01

    In this paper, we propose a trust-based vehicular platoon crowdsensing scheme, named TripSense, in VANET. The proposed TripSense scheme introduces a trust-based system to evaluate vehicles’ sensing abilities and then selects the more capable vehicles in order to improve sensing results accuracy. In addition, the sensing tasks are accomplished by platoon member vehicles and preprocessed by platoon head vehicles before the data are uploaded to server. Hence, it is less time-consuming and more efficient compared with the way where the data are submitted by individual platoon member vehicles. Hence it is more suitable in ephemeral networks like VANET. Moreover, our proposed TripSense scheme integrates unlinkable pseudo-ID techniques to achieve PM vehicle identity privacy, and employs a privacy-preserving sensing vehicle selection scheme without involving the PM vehicle’s trust score to keep its location privacy. Detailed security analysis shows that our proposed TripSense scheme not only achieves desirable privacy requirements but also resists against attacks launched by adversaries. In addition, extensive simulations are conducted to show the correctness and effectiveness of our proposed scheme. PMID:27258287

  9. Geometrical Positioning Schemes Based on Hybrid Lines of Position

    NASA Astrophysics Data System (ADS)

    Chen, Chien-Sheng; Lin, Jium-Ming; Liu, Wen-Hsiung; Chi, Ching-Lung

    To achieve more accurate measurements of the mobile station (MS) location, it is possible to integrate many kinds of measurements. In this paper we proposed several simpler methods that utilized time of arrival (TOA) at three base stations (BSs) and the angle of arrival (AOA) information at the serving BS to give location estimation of the MS in non-line-of-sight (NLOS) environments. From the viewpoint of geometric approach, for each a TOA value measured at any BS, one can generate a circle. Rather than applying the nonlinear circular lines of position (LOP), the proposed methods are much easier by using linear LOP to determine the MS. Numerical results demonstrate that the calculation time of using linear LOP is much less than employing circular LOP. Although the location precision of using linear LOP is only reduced slightly. However, the proposed efficient methods by using linear LOP can still provide precise solution of MS location and reduce the computational effort greatly. In addition, the proposed methods with less effort can mitigate the NLOS effect, simply by applying the weighted sum of the intersections between different linear LOP and the AOA line, without requiring priori knowledge of NLOS error statistics. Simulation results show that the proposed methods can always yield superior performance in comparison with Taylor series algorithm (TSA) and the hybrid lines of position algorithm (HLOP).

  10. Performance Analysis of Positive-feedback-based Active Anti-islanding Schemes for Inverter-Based Distributed Generators

    SciTech Connect

    Du, Pengwei; Aponte, Erick E.; Nelson, J. Keith

    2010-06-14

    Recently proposed positive-feedback-based anti-islanding schemes (AI) are highly effective in preventing islanding without causing any degradation in power quality. This paper aims to analyze the performance of these schemes quantitatively in the context of the dynamic models of inverter-based distributed generators (DG). In this study, the characteristics of these active anti-islanding methods are discussed and design guidelines are derived.

  11. Channel aware HARQ scheme based on LDPC codes for land mobile satellite communication system

    NASA Astrophysics Data System (ADS)

    Yang, Yongli; Zhu, Guangxi; Wang, Desheng; Wu, Lifen

    2007-11-01

    In this paper, a channel aware HARQ (CA-HARQ) scheme based on data punctured rate compatible LDPC (DP-LDPC) codes, which might satisfy the demand for bandwidth and rate in land mobile communication system, is proposed. The scheme is based on type II HARQ technique cooperated with a DP- LDPC code. In the proposed scheme, the effective rate of the LDPC code is adapted according to the channel quality information (CQI) estimated at the receiver, so as to decrease the redundancy when the channel is good and vice versa, the retransmitted blocks are combined with the previous information transmitted to achieve high probability of successful decoding. In this paper, we use a 2-bit CQI feedback scheme. Simulation results, which based on a land mobile satellite channel, show that the proposed channel aware H-ARQ scheme based on DP-LDPC codes improved the throughput by 0.4dB at low SNR compared to a pure DP-LDPC type II HARQ, and it can also be an effective solution to compensate rain attenuation and multipath fading in land mobile satellite systems.

  12. Efficient and provable secure pairing-free security-mediated identity-based identification schemes.

    PubMed

    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

  13. Modeling and Performance Analysis of an Improved Movement-Based Location Management Scheme for Packet-Switched Mobile Communication Systems

    PubMed Central

    Chung, Yun Won; 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. PMID:24741363

  14. Coupled-cluster method: A lattice-path-based subsystem approximation scheme for quantum lattice models

    SciTech Connect

    Bishop, R. F.; Li, P. H. Y.

    2011-04-15

    An approximation hierarchy, called the lattice-path-based subsystem (LPSUBm) approximation scheme, is described for the coupled-cluster method (CCM). It is applicable to systems defined on a regular spatial lattice. We then apply it to two well-studied prototypical (spin-(1/2) Heisenberg antiferromagnetic) spin-lattice models, namely, the XXZ and the XY models on the square lattice in two dimensions. Results are obtained in each case for the ground-state energy, the ground-state sublattice magnetization, and the quantum critical point. They are all in good agreement with those from such alternative methods as spin-wave theory, series expansions, quantum Monte Carlo methods, and the CCM using the alternative lattice-animal-based subsystem (LSUBm) and the distance-based subsystem (DSUBm) schemes. Each of the three CCM schemes (LSUBm, DSUBm, and LPSUBm) for use with systems defined on a regular spatial lattice is shown to have its own advantages in particular applications.

  15. Coupled-cluster method: A lattice-path-based subsystem approximation scheme for quantum lattice models

    NASA Astrophysics Data System (ADS)

    Bishop, R. F.; Li, P. H. Y.

    2011-04-01

    An approximation hierarchy, called the lattice-path-based subsystem (LPSUBm) approximation scheme, is described for the coupled-cluster method (CCM). It is applicable to systems defined on a regular spatial lattice. We then apply it to two well-studied prototypical (spin-(1)/(2) Heisenberg antiferromagnetic) spin-lattice models, namely, the XXZ and the XY models on the square lattice in two dimensions. Results are obtained in each case for the ground-state energy, the ground-state sublattice magnetization, and the quantum critical point. They are all in good agreement with those from such alternative methods as spin-wave theory, series expansions, quantum Monte Carlo methods, and the CCM using the alternative lattice-animal-based subsystem (LSUBm) and the distance-based subsystem (DSUBm) schemes. Each of the three CCM schemes (LSUBm, DSUBm, and LPSUBm) for use with systems defined on a regular spatial lattice is shown to have its own advantages in particular applications.

  16. Metro-access integrated network based on optical OFDMA with dynamic sub-carrier allocation and power distribution.

    PubMed

    Zhang, Chongfu; Zhang, Qiongli; Chen, Chen; Jiang, Ning; Liu, Deming; Qiu, Kun; Liu, Shuang; Wu, Baojian

    2013-01-28

    We propose and demonstrate a novel optical orthogonal frequency-division multiple access (OFDMA)-based metro-access integrated network with dynamic resource allocation. It consists of a single fiber OFDMA ring and many single fiber OFDMA trees, which transparently integrates metropolitan area networks with optical access networks. The single fiber OFDMA ring connects the core network and the central nodes (CNs), the CNs are on demand reconfigurable and use multiple orthogonal sub-carriers to realize parallel data transmission and dynamic resource allocation, meanwhile, they can also implement flexible power distribution. The remote nodes (RNs) distributed in the user side are connected by the single fiber OFDMA trees with the corresponding CN. The obtained results indicate that our proposed metro-access integrated network is feasible and the power distribution is agile. PMID:23389228

  17. Realizable high-order finite-volume schemes for quadrature-based moment methods applied to diffusion population balance equations

    NASA Astrophysics Data System (ADS)

    Vikas, V.; Wang, Z. J.; Fox, R. O.

    2013-09-01

    Population balance equations with advection and diffusion terms can be solved using quadrature-based moment methods. Recently, high-order realizable finite-volume schemes with appropriate realizability criteria have been derived for the advection term. However, hitherto no work has been reported with respect to realizability problems for the diffusion term. The current work focuses on developing high-order realizable finite-volume schemes for diffusion. The pitfalls of existing finite-volume schemes for the diffusion term based on the reconstruction of moments are discussed, and it is shown that realizability can be guaranteed only with the 2nd-order scheme and that the realizability criterion for the 2nd-order scheme is the same as the stability criterion. However, realizability of moments cannot be guaranteed when higher-order moment-based reconstruction schemes are used. To overcome this problem, realizable high-order finite-volume schemes based on the reconstruction of weights and abscissas are proposed and suitable realizability criteria are derived. The realizable schemes can achieve higher than 2nd-order accuracy for problems with smoothly varying abscissas. In the worst-case scenario of highly nonlinear abscissas, the realizable schemes are 2nd-order accurate but have lower error magnitudes compared to existing schemes. The results obtained using the realizable high-order schemes are shown to be consistent with those obtained using the 2nd-order moment-based reconstruction scheme.

  18. A two-stage spectrum sensing scheme based on energy detection and a novel multitaper method

    NASA Astrophysics Data System (ADS)

    Qi, Pei-Han; Li, Zan; Si, Jiang-Bo; Xiong, Tian-Yi

    2015-04-01

    Wideband spectrum sensing has drawn much attention in recent years since it provides more opportunities to the secondary users. However, wideband spectrum sensing requires a long time and a complex mechanism at the sensing terminal. A two-stage wideband spectrum sensing scheme is considered to proceed spectrum sensing with low time consumption and high performance to tackle this predicament. In this scheme, a novel multitaper spectrum sensing (MSS) method is proposed to mitigate the poor performance of energy detection (ED) in the low signal-to-noise ratio (SNR) region. The closed-form expression of the decision threshold is derived based on the Neyman-Pearson criterion and the probability of detection in the Rayleigh fading channel is analyzed. An optimization problem is formulated to maximize the probability of detection of the proposed two-stage scheme and the average sensing time of the two-stage scheme is analyzed. Numerical results validate the efficiency of MSS and show that the two-stage spectrum sensing scheme enjoys higher performance in the low SNR region and lower time cost in the high SNR region than the single-stage scheme. Project supported by the National Natural Science Foundation of China (Grant No. 61301179), the China Postdoctoral Science Foundation (Grant No. 2014M550479), and the Doctorial Programs Foundation of the Ministry of Education, China (Grant No. 20110203110011).

  19. 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

    2016-01-01

    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

  20. 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

  1. A New Subcarrier Allocation Strategy for MIMO-OFDMA Multicellular Networks Based on Cooperative Interference Mitigation

    PubMed Central

    Gkonis, Panagiotis K.; Seimeni, Maria A.; Asimakis, Nikolaos P.; Kaklamani, Dimitra I.; Venieris, Iakovos S.

    2014-01-01

    The goal of the study presented in this paper is to investigate the performance of a new subcarrier allocation strategy for Orthogonal Frequency Division Multiple Access (OFDMA) multicellular networks which employ Multiple Input Multiple Output (MIMO) architecture. For this reason, a hybrid system-link level simulator has been developed executing independent Monte Carlo (MC) simulations in parallel. Up to two tiers of cells around the central cell are taken into consideration and increased loading per cell. The derived results indicate that this strategy can provide up to 12% capacity gain for 16-QAM modulation and two tiers of cells around the central cell in a symmetric 2 × 2 MIMO configuration. This gain is derived when comparing the proposed strategy to the traditional approach of allocating subcarriers that maximize only the desired user's signal. PMID:24683351

  2. Allocating attention to distractor locations is based on top-down expectations.

    PubMed

    Lahav, Aya; Tsal, Yehoshua

    2013-09-01

    Failures of selective attention may be explained by the attentional white bear (AWB) hypothesis maintaining that prior knowledge of distractor location causes attentional allocation to it. The AWB is demonstrated by embedding infrequent trials of two simultaneous dots among flanker trials. The dot at the expected distractor location is perceived as appearing before the dot at the expected empty location, indicating attentional allocation to expected distractor locations. A major requirement of the AWB hypothesis is that it occurs in a top-down manner due to expectations. We devised a variation of the original AWB experiment, which enabled us to differentiate between the top-down and bottom-up contributions. The results show that top-down expectancies, which are a critical part of the AWB characterization, occur independently of bottom-up contributions. PMID:23425450

  3. [Need-based resource allocation--experiences with the RAWP formula in Great Britain].

    PubMed

    Brand, H; Menke, R

    1997-07-01

    The RAWP formula used for resource allocation in Great Britain between 1976 and 1991 is a morbidity-oriented instrument of controlling, which has so far received only little attention in Germany. The development of this model was supported by the intention to intervene in the regional pattern of hospital supply by means of resource allocation and to refine it according to the guiding principles of equity and efficiency. The basic elements-regional population, average bed use, ICD chapter-specific SMRs-are discussed and the various modifications outlined. The RAWP formula's potentials of controlling resulted in a progressive reduction of the apparent disparities between regions in hospital supply, and knee was considered to be a "qualified success". The future development in the sense of an internal market addressed. PMID:9333384

  4. Safety assurance of assistive devices based on a two-level checking scheme.

    PubMed

    Lin, Hua-Sheng; Chang, Yi-Chu; Chen, Chiun-Fan; Luh, Jer-Junn; Chiou, Ying-Han; Lai, Jin-Shin; Kuog, T-S

    2005-01-01

    The increasing number of physically challenged individuals has boosted the demand of powered wheelchairs. This paper is on the subject of a DSP (Digital Signal Processors) based assistive system, which is associated with a two-level checking scheme. The assistive system takes on the M3S (Multiple Master Multiple Slave) regulation for the assurance of safety. The CAN (Control Area Networks) embedded module in the DSP provides robust transmission of information within the system. The hardware interfaces based on the two-level checking scheme is implemented in input devices (e.g. joystick, head control apparatus) and in output devices (e.g. manipulator, prime mover motors). PMID:17281868

  5. A new Fourier transform based CBIR scheme for mammographic mass classification: a preliminary invariance assessment

    NASA Astrophysics Data System (ADS)

    Gundreddy, Rohith Reddy; Tan, Maxine; Qui, Yuchen; Zheng, Bin

    2015-03-01

    The purpose of this study is to develop and test a new content-based image retrieval (CBIR) scheme that enables to achieve higher reproducibility when it is implemented in an interactive computer-aided diagnosis (CAD) system without significantly reducing lesion classification performance. This is a new Fourier transform based CBIR algorithm that determines image similarity of two regions of interest (ROI) based on the difference of average regional image pixel value distribution in two Fourier transform mapped images under comparison. A reference image database involving 227 ROIs depicting the verified soft-tissue breast lesions was used. For each testing ROI, the queried lesion center was systematically shifted from 10 to 50 pixels to simulate inter-user variation of querying suspicious lesion center when using an interactive CAD system. The lesion classification performance and reproducibility as the queried lesion center shift were assessed and compared among the three CBIR schemes based on Fourier transform, mutual information and Pearson correlation. Each CBIR scheme retrieved 10 most similar reference ROIs and computed a likelihood score of the queried ROI depicting a malignant lesion. The experimental results shown that three CBIR schemes yielded very comparable lesion classification performance as measured by the areas under ROC curves with the p-value greater than 0.498. However, the CBIR scheme using Fourier transform yielded the highest invariance to both queried lesion center shift and lesion size change. This study demonstrated the feasibility of improving robustness of the interactive CAD systems by adding a new Fourier transform based image feature to CBIR schemes.

  6. Optimal allocation of bulk water supplies to competing use sectors based on economic criterion - An application to the Chao Phraya River Basin, Thailand

    NASA Astrophysics Data System (ADS)

    Divakar, L.; Babel, M. S.; Perret, S. R.; Gupta, A. Das

    2011-04-01

    SummaryThe study develops a model for optimal bulk allocations of limited available water based on an economic criterion to competing use sectors such as agriculture, domestic, industry and hydropower. The model comprises a reservoir operation module (ROM) and a water allocation module (WAM). ROM determines the amount of water available for allocation, which is used as an input to WAM with an objective function to maximize the net economic benefits of bulk allocations to different use sectors. The total net benefit functions for agriculture and hydropower sectors and the marginal net benefit from domestic and industrial sectors are established and are categorically taken as fixed in the present study. The developed model is applied to the Chao Phraya basin in Thailand. The case study results indicate that the WAM can improve net economic returns compared to the current water allocation practices.

  7. Variance reduction for Fokker–Planck based particle Monte Carlo schemes

    SciTech Connect

    Gorji, M. Hossein Andric, Nemanja; Jenny, Patrick

    2015-08-15

    Recently, Fokker–Planck based particle Monte Carlo schemes have been proposed and evaluated for simulations of rarefied gas flows [1–3]. In this paper, the variance reduction for particle Monte Carlo simulations based on the Fokker–Planck model is considered. First, deviational based schemes were derived and reviewed, and it is shown that these deviational methods are not appropriate for practical Fokker–Planck based rarefied gas flow simulations. This is due to the fact that the deviational schemes considered in this study lead either to instabilities in the case of two-weight methods or to large statistical errors if the direct sampling method is applied. Motivated by this conclusion, we developed a novel scheme based on correlated stochastic processes. The main idea here is to synthesize an additional stochastic process with a known solution, which is simultaneously solved together with the main one. By correlating the two processes, the statistical errors can dramatically be reduced; especially for low Mach numbers. To assess the methods, homogeneous relaxation, planar Couette and lid-driven cavity flows were considered. For these test cases, it could be demonstrated that variance reduction based on parallel processes is very robust and effective.

  8. Variance reduction for Fokker-Planck based particle Monte Carlo schemes

    NASA Astrophysics Data System (ADS)

    Gorji, M. Hossein; Andric, Nemanja; Jenny, Patrick

    2015-08-01

    Recently, Fokker-Planck based particle Monte Carlo schemes have been proposed and evaluated for simulations of rarefied gas flows [1-3]. In this paper, the variance reduction for particle Monte Carlo simulations based on the Fokker-Planck model is considered. First, deviational based schemes were derived and reviewed, and it is shown that these deviational methods are not appropriate for practical Fokker-Planck based rarefied gas flow simulations. This is due to the fact that the deviational schemes considered in this study lead either to instabilities in the case of two-weight methods or to large statistical errors if the direct sampling method is applied. Motivated by this conclusion, we developed a novel scheme based on correlated stochastic processes. The main idea here is to synthesize an additional stochastic process with a known solution, which is simultaneously solved together with the main one. By correlating the two processes, the statistical errors can dramatically be reduced; especially for low Mach numbers. To assess the methods, homogeneous relaxation, planar Couette and lid-driven cavity flows were considered. For these test cases, it could be demonstrated that variance reduction based on parallel processes is very robust and effective.

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

    PubMed

    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

  10. 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

  11. Optimization model for the allocation of water resources based on the maximization of employment in the agriculture and industry sectors

    NASA Astrophysics Data System (ADS)

    Habibi Davijani, M.; Banihabib, M. E.; Nadjafzadeh Anvar, A.; Hashemi, S. R.

    2016-02-01

    In many discussions, work force is mentioned as the most important factor of production. Principally, work force is a factor which can compensate for the physical and material limitations and shortcomings of other factors to a large extent which can help increase the production level. On the other hand, employment is considered as an effective factor in social issues. The goal of the present research is the allocation of water resources so as to maximize the number of jobs created in the industry and agriculture sectors. An objective that has attracted the attention of policy makers involved in water supply and distribution is the maximization of the interests of beneficiaries and consumers in case of certain policies adopted. The present model applies the particle swarm optimization (PSO) algorithm in order to determine the optimum amount of water allocated to each water-demanding sector, area under cultivation, agricultural production, employment in the agriculture sector, industrial production and employment in the industry sector. Based on the results obtained from this research, by optimally allocating water resources in the central desert region of Iran, 1096 jobs can be created in the industry and agriculture sectors, which constitutes an improvement of about 13% relative to the previous situation (non-optimal water utilization). It is also worth mentioning that by optimizing the employment factor as a social parameter, the other areas such as the economic sector are influenced as well. For example, in this investigation, the resulting economic benefits (incomes) have improved from 73 billion Rials at baseline employment figures to 112 billion Rials in the case of optimized employment condition. Therefore, it is necessary to change the inter-sector and intra-sector water allocation models in this region, because this change not only leads to more jobs in this area, but also causes an improvement in the region's economic conditions.

  12. BossPro: a biometrics-based obfuscation scheme for software protection

    NASA Astrophysics Data System (ADS)

    Kuseler, Torben; Lami, Ihsan A.; Al-Assam, Hisham

    2013-05-01

    This paper proposes to integrate biometric-based key generation into an obfuscated interpretation algorithm to protect authentication application software from illegitimate use or reverse-engineering. This is especially necessary for mCommerce because application programmes on mobile devices, such as Smartphones and Tablet-PCs are typically open for misuse by hackers. Therefore, the scheme proposed in this paper ensures that a correct interpretation / execution of the obfuscated program code of the authentication application requires a valid biometric generated key of the actual person to be authenticated, in real-time. Without this key, the real semantics of the program cannot be understood by an attacker even if he/she gains access to this application code. Furthermore, the security provided by this scheme can be a vital aspect in protecting any application running on mobile devices that are increasingly used to perform business/financial or other security related applications, but are easily lost or stolen. The scheme starts by creating a personalised copy of any application based on the biometric key generated during an enrolment process with the authenticator as well as a nuance created at the time of communication between the client and the authenticator. The obfuscated code is then shipped to the client's mobile devise and integrated with real-time biometric extracted data of the client to form the unlocking key during execution. The novelty of this scheme is achieved by the close binding of this application program to the biometric key of the client, thus making this application unusable for others. Trials and experimental results on biometric key generation, based on client's faces, and an implemented scheme prototype, based on the Android emulator, prove the concept and novelty of this proposed scheme.

  13. Robust chaotic map-based authentication and key agreement scheme with strong anonymity for telecare medicine information systems.

    PubMed

    Jiang, Qi; Ma, Jianfeng; Lu, Xiang; Tian, Youliang

    2014-02-01

    To ensure only authorized access to medical services, several authentication schemes for telecare medicine information systems (TMIS) have been proposed in the literature. Due to its better performance than traditional cryptography, Hao et al. proposed an authentication scheme for TMIS using chaotic map based cryptography. They claimed that their scheme could resist various attacks, including the smart card stolen attack. However, we identify that their scheme is vulnerable to the stolen smart card attack. The reason causing the stolen smart card attack is that the scheme is designed based on the assumption that the scheme itself achieves user untraceability. Then, we propose a robust authentication and key agreement scheme. Compared with the previous schemes, our scheme not only enjoys more security features, but also has better efficiency. Our analysis indicates that designing a two-factor authentication scheme based on the assumption that privacy protection is achieved in the scheme itself may pose potential security risks. The lesson learned is that, we should avoid this situation in the future design of two-factor authentication schemes. PMID:24493073

  14. Comparison of Two Multilocus Sequence Based Genotyping Schemes for Leptospira Species

    PubMed Central

    Boonsilp, Siriphan; Wuthiekanun, Vanaporn; Nalam, Kishore; Spratt, Brian G.; Aanensen, David M.; Smythe, Lee D.; Ahmed, Niyaz; Feil, Edward J.; Hartskeerl, Rudy A.; Peacock, Sharon J.

    2011-01-01

    Background Several sequence based genotyping schemes have been developed for Leptospira spp. The objective of this study was to genotype a collection of clinical and reference isolates using the two most commonly used schemes and compare and contrast the results. Methods and Findings A total of 48 isolates consisting of L. interrogans (n = 40) and L. kirschneri (n = 8) were typed by the 7 locus MLST scheme described by Thaipadungpanit et al., and the 6 locus genotyping scheme described by Ahmed et al., (termed 7L and 6L, respectively). Two L. interrogans isolates were not typed using 6L because of a deletion of three nucleotides in lipL32. The remaining 46 isolates were resolved into 21 sequence types (STs) by 7L, and 30 genotypes by 6L. Overall nucleotide diversity (based on concatenated sequence) was 3.6% and 2.3% for 7L and 6L, respectively. The D value (discriminatory ability) of 7L and 6L were comparable, i.e. 92.0 (95% CI 87.5–96.5) vs. 93.5 (95% CI 88.6–98.4). The dN/dS ratios calculated for each locus indicated that none were under positive selection. Neighbor joining trees were reconstructed based on the concatenated sequences for each scheme. Both trees showed two distinct groups corresponding to L. interrogans and L. kirschneri, and both identified two clones containing 10 and 7 clinical isolates, respectively. There were six instances in which 6L split single STs as defined by 7L into closely related clusters. We noted two discrepancies between the trees in which the genetic relatedness between two pairs of strains were more closely related by 7L than by 6L. Conclusions This genetic analysis indicates that the two schemes are comparable. We discuss their practical advantages and disadvantages. PMID:22087342

  15. Double-image encryption scheme combining DWT-based compressive sensing with discrete fractional random transform

    NASA Astrophysics Data System (ADS)

    Zhou, Nanrun; Yang, Jianping; Tan, Changfa; Pan, Shumin; Zhou, Zhihong

    2015-11-01

    A new discrete fractional random transform based on two circular matrices is designed and a novel double-image encryption-compression scheme is proposed by combining compressive sensing with discrete fractional random transform. The two random circular matrices and the measurement matrix utilized in compressive sensing are constructed by using a two-dimensional sine Logistic modulation map. Two original images can be compressed, encrypted with compressive sensing and connected into one image. The resulting image is re-encrypted by Arnold transform and the discrete fractional random transform. Simulation results and security analysis demonstrate the validity and security of the scheme.

  16. Wavelength initialization employing wavelength recognition scheme in WDM-PON based on tunable lasers

    NASA Astrophysics Data System (ADS)

    Mun, Sil-Gu; Lee, Eun-Gu; Lee, Jong Hyun; Lee, Sang Soo; Lee, Jyung Chan

    2015-01-01

    We proposed a simple method to initialize the wavelength of tunable lasers in WDM-PON employing wavelength recognition scheme with an optical filter as a function of wavelength and accomplished plug and play operation. We also implemented a transceiver based on our proposed wavelength initialization scheme and then experimentally demonstrated the feasibility in WDM-PON configuration guaranteeing 16 channels with 100 GHz channel spacing. Our proposal is a cost-effective and easy-to-install method to realize the wavelength initialization of ONU. In addition, this method will support compatibility with all kind of tunable laser regardless of their structures and operating principles.

  17. An algorithm for calculating exam quality as a basis for performance-based allocation of funds at medical schools

    PubMed Central

    Kirschstein, Timo; Wolters, Alexander; Lenz, Jan-Hendrik; Fröhlich, Susanne; Hakenberg, Oliver; Kundt, Günther; Darmüntzel, Martin; Hecker, Michael; Altiner, Attila; Müller-Hilke, Brigitte

    2016-01-01

    Objective: The amendment of the Medical Licensing Act (ÄAppO) in Germany in 2002 led to the introduction of graded assessments in the clinical part of medical studies. This, in turn, lent new weight to the importance of written tests, even though the minimum requirements for exam quality are sometimes difficult to reach. Introducing exam quality as a criterion for the award of performance-based allocation of funds is expected to steer the attention of faculty members towards more quality and perpetuate higher standards. However, at present there is a lack of suitable algorithms for calculating exam quality. Methods: In the spring of 2014, the students‘ dean commissioned the „core group“ for curricular improvement at the University Medical Center in Rostock to revise the criteria for the allocation of performance-based funds for teaching. In a first approach, we developed an algorithm that was based on the results of the most common type of exam in medical education, multiple choice tests. It included item difficulty and discrimination, reliability as well as the distribution of grades achieved. Results: This algorithm quantitatively describes exam quality of multiple choice exams. However, it can also be applied to exams involving short assay questions and the OSCE. It thus allows for the quantitation of exam quality in the various subjects and – in analogy to impact factors and third party grants – a ranking among faculty. Conclusion: Our algorithm can be applied to all test formats in which item difficulty, the discriminatory power of the individual items, reliability of the exam and the distribution of grades are measured. Even though the content validity of an exam is not considered here, we believe that our algorithm is suitable as a general basis for performance-based allocation of funds. PMID:27275509

  18. Improvement of a Privacy Authentication Scheme Based on Cloud for Medical Environment.

    PubMed

    Chiou, Shin-Yan; Ying, Zhaoqin; Liu, Junqiang

    2016-04-01

    Medical systems allow patients to receive care at different hospitals. However, this entails considerable inconvenience through the need to transport patients and their medical records between hospitals. The development of Telecare Medicine Information Systems (TMIS) makes it easier for patients to seek medical treatment and to store and access medical records. However, medical data stored in TMIS is not encrypted, leaving patients' private data vulnerable to external leaks. In 2014, scholars proposed a new cloud-based medical information model and authentication scheme which would not only allow patients to remotely access medical services but also protects patient privacy. However, this scheme still fails to provide patient anonymity and message authentication. Furthermore, this scheme only stores patient medical data, without allowing patients to directly access medical advice. Therefore, we propose a new authentication scheme, which provides anonymity, unlinkability, and message authentication, and allows patients to directly and remotely consult with doctors. In addition, our proposed scheme is more efficient in terms of computation cost. The proposed system was implemented in Android system to demonstrate its workability. PMID:26875078

  19. A Non-symmetric Digital Image Secure Communication Scheme Based on Generalized Chaos Synchronization System

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao-Hong; Min, Le-Quan

    2005-12-01

    Based on a generalized chaos synchronization system and a discrete Sinai map, a non-symmetric true color (RGB) digital image secure communication scheme is proposed. The scheme first changes an ordinary RGB digital image with 8 bits into unrecognizable disorder codes and then transforms the disorder codes into an RGB digital image with 16 bits for transmitting. A receiver uses a non-symmetric key to verify the authentication of the received data origin, and decrypts the ciphertext. The scheme can encrypt and decrypt most formatted digital RGB images recognized by computers, and recover the plaintext almost without any errors. The scheme is suitable to be applied in network image communications. The analysis of the key space, sensitivity of key parameters, and correlation of encrypted images imply that this scheme has sound security. The project supported by National Natural Science Foundation of China under Grant Nos. 60074034 and 70271068, the Foundation for University Key Teachers, and the Research Fund for the Doctoral Program of Higher Education under Grant No. 20020008004 by the Ministry of Education of China

  20. Mental workload prediction based on attentional resource allocation and information processing.

    PubMed

    Xiao, Xu; Wanyan, Xiaoru; Zhuang, Damin

    2015-01-01

    Mental workload is an important component in complex human-machine systems. The limited applicability of empirical workload measures produces the need for workload modeling and prediction methods. In the present study, a mental workload prediction model is built on the basis of attentional resource allocation and information processing to ensure pilots' accuracy and speed in understanding large amounts of flight information on the cockpit display interface. Validation with an empirical study of an abnormal attitude recovery task showed that this model's prediction of mental workload highly correlated with experimental results. This mental workload prediction model provides a new tool for optimizing human factors interface design and reducing human errors. PMID:26406085

  1. A Dynamic CFP Allocation and Opportunity Contention-Based WBAN MAC Protocol

    NASA Astrophysics Data System (ADS)

    Seo, Young-Sun; Kim, Dae-Young; Cho, Jinsung

    WBANs provide communication services in the vicinity of the human body. Since WBANs utilize both MICS frequency band for implant medical applications and ISM frequency band for medical and consumer electronics (CE) applications, MAC protocols in WBAN should be designed considering flexibility between medical and CE applications. In this letter, we identify the requirements of WBAN MAC protocols and propose a WBAN MAC protocol which satisfies the requirements. In order to provide transmission flexibility for various applications, we present the dynamic CFP allocation and opportunity period. Extensive simulation results show that the proposed protocol achieves improved throughput and latency in WBAN environment compared with IEEE 802.15.4.

  2. Iterative resource allocation based on propagation feature of node for identifying the influential nodes

    NASA Astrophysics Data System (ADS)

    Zhong, Lin-Feng; Liu, Jian-Guo; Shang, Ming-Sheng

    2015-10-01

    The identification of the influential nodes in networks is one of the most promising domains. In this paper, we present an improved iterative resource allocation (IIRA) method by considering the centrality information of neighbors and the influence of spreading rate for a target node. Comparing with the results of the Susceptible Infected Recovered (SIR) model for four real networks, the IIRA method could identify influential nodes more accurately than the tradition IRA method. Specially, in the Erdös network, Kendall's tau could be enhanced 23% when the spreading rate is 0.12. In the Protein network, Kendall's tau could be enhanced 24% when the spreading rate is 0.08.

  3. A secure and robust password-based remote user authentication scheme using smart cards for the integrated EPR information system.

    PubMed

    Das, Ashok Kumar

    2015-03-01

    An integrated EPR (Electronic Patient Record) information system of all the patients provides the medical institutions and the academia with most of the patients' information in details for them to make corrective decisions and clinical decisions in order to maintain and analyze patients' health. In such system, the illegal access must be restricted and the information from theft during transmission over the insecure Internet must be prevented. Lee et al. proposed an efficient password-based remote user authentication scheme using smart card for the integrated EPR information system. Their scheme is very efficient due to usage of one-way hash function and bitwise exclusive-or (XOR) operations. However, in this paper, we show that though their scheme is very efficient, their scheme has three security weaknesses such as (1) it has design flaws in password change phase, (2) it fails to protect privileged insider attack and (3) it lacks the formal security verification. We also find that another recently proposed Wen's scheme has the same security drawbacks as in Lee at al.'s scheme. In order to remedy these security weaknesses found in Lee et al.'s scheme and Wen's scheme, we propose a secure and efficient password-based remote user authentication scheme using smart cards for the integrated EPR information system. We show that our scheme is also efficient as compared to Lee et al.'s scheme and Wen's scheme as our scheme only uses one-way hash function and bitwise exclusive-or (XOR) operations. Through the security analysis, we show that our scheme is secure against possible known attacks. Furthermore, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool and show that our scheme is secure against passive and active attacks. PMID:25666924

  4. A New Optical Scheme for a Polarimetric-Based Glucose Sensor

    NASA Technical Reports Server (NTRS)

    Ansari, Rafat R.; Boeckle, Stefan; Rovati, Luigi; Salzman, Jack A. (Technical Monitor)

    2002-01-01

    We describe a new optical scheme to perform polarimetric measurements to detect glucose concentration in the aqueous humor of a model eye. The ultimate aim is to apply this technique in designing a new instrument for measuring glucose levels in diabetic patients routinely, frequently, and non-invasively. The scheme exploits the Brewsterreflection of circularly polarized light off of the lens of the eye. Theoretically, this backreflected linearly polarized light on its way to the detector is expected to rotate its state of polarization due to the presence of glucose molecules in the aqueous humor of patients. An experimental laboratory setup based on this scheme was designed and tested by measuring a range of known concentration of glucose solutions dissolved in water.

  5. Message Embedded Chaotic Masking Synchronization Scheme Based on the Generalized Lorenz System and Its Security Analysis

    NASA Astrophysics Data System (ADS)

    Čelikovský, Sergej; Lynnyk, Volodymyr

    This paper focuses on the design of the novel chaotic masking scheme via message embedded synchronization. A general class of the systems allowing the message embedded synchronization is presented here, moreover, it is shown that the generalized Lorenz system belongs to this class. Furthermore, the secure encryption scheme based on the message embedded synchronization is proposed. This scheme injects the embedded message into the dynamics of the transmitter as well, ensuring thereby synchronization with theoretically zero synchronization error. To ensure the security, the embedded message is a sum of the message and arbitrary bounded function of the internal transmitter states that is independent of the scalar synchronization signal. The hexadecimal alphabet will be used to form a ciphertext making chaotic dynamics of the transmitter even more complicated in comparison with the transmitter influenced just by the binary step-like function. All mentioned results and their security are tested and demonstrated by numerical experiments.

  6. Integrated optimal allocation model for complex adaptive system of water resources management (I): Methodologies

    NASA Astrophysics Data System (ADS)

    Zhou, Yanlai; Guo, Shenglian; Xu, Chong-Yu; Liu, Dedi; Chen, Lu; Ye, Yushi

    2015-12-01

    Due to the adaption, dynamic and multi-objective characteristics of complex water resources system, it is a considerable challenge to manage water resources in an efficient, equitable and sustainable way. An integrated optimal allocation model is proposed for complex adaptive system of water resources management. The model consists of three modules: (1) an agent-based module for revealing evolution mechanism of complex adaptive system using agent-based, system dynamic and non-dominated sorting genetic algorithm II methods, (2) an optimal module for deriving decision set of water resources allocation using multi-objective genetic algorithm, and (3) a multi-objective evaluation module for evaluating the efficiency of the optimal module and selecting the optimal water resources allocation scheme using project pursuit method. This study has provided a theoretical framework for adaptive allocation, dynamic allocation and multi-objective optimization for a complex adaptive system of water resources management.

  7. Provider payment in community-based health insurance schemes in developing countries: a systematic review

    PubMed Central

    Robyn, Paul Jacob; Sauerborn, Rainer; Bärnighausen, Till

    2013-01-01

    Objectives Community-based health insurance (CBI) is a common mechanism to generate financial resources for health care in developing countries. We review for the first time provider payment methods used in CBI in developing countries and their impact on CBI performance. Methods We conducted a systematic review of the literature on provider payment methods used by CBI in developing countries published up to January 2010. Results Information on provider payment was available for a total of 32 CBI schemes in 34 reviewed publications: 17 schemes in South Asia, 10 in sub-Saharan Africa, 4 in East Asia and 1 in Latin America. Various types of provider payment were applied by the CBI schemes: 17 used fee-for-service, 12 used salaries, 9 applied a coverage ceiling, 7 used capitation and 6 applied a co-insurance. The evidence suggests that provider payment impacts CBI performance through provider participation and support for CBI, population enrolment and patient satisfaction with CBI, quantity and quality of services provided and provider and patient retention. Lack of provider participation in designing and choosing a CBI payment method can lead to reduced provider support for the scheme. Conclusion CBI schemes in developing countries have used a wide range of provider payment methods. The existing evidence suggests that payment methods are a key determinant of CBI performance and sustainability, but the strength of this evidence is limited since it is largely based on observational studies rather than on trials or on quasi-experimental research. According to the evidence, provider payment can affect provider participation, satisfaction and retention in CBI; the quantity and quality of services provided to CBI patients; patient demand of CBI services; and population enrollment, risk pooling and financial sustainability of CBI. CBI schemes should carefully consider how their current payment methods influence their performance, how changes in the methods could improve

  8. A study of the spreading scheme for viral marketing based on a complex network model

    NASA Astrophysics Data System (ADS)

    Yang, Jianmei; Yao, Canzhong; Ma, Weicheng; Chen, Guanrong

    2010-02-01

    Buzzword-based viral marketing, known also as digital word-of-mouth marketing, is a marketing mode attached to some carriers on the Internet, which can rapidly copy marketing information at a low cost. Viral marketing actually uses a pre-existing social network where, however, the scale of the pre-existing network is believed to be so large and so random, so that its theoretical analysis is intractable and unmanageable. There are very few reports in the literature on how to design a spreading scheme for viral marketing on real social networks according to the traditional marketing theory or the relatively new network marketing theory. Complex network theory provides a new model for the study of large-scale complex systems, using the latest developments of graph theory and computing techniques. From this perspective, the present paper extends the complex network theory and modeling into the research of general viral marketing and develops a specific spreading scheme for viral marking and an approach to design the scheme based on a real complex network on the QQ instant messaging system. This approach is shown to be rather universal and can be further extended to the design of various spreading schemes for viral marketing based on different instant messaging systems.

  9. Multiscale deep drawing analysis of dual-phase steels using grain cluster-based RGC scheme

    NASA Astrophysics Data System (ADS)

    Tjahjanto, D. D.; Eisenlohr, P.; Roters, F.

    2015-06-01

    Multiscale modelling and simulation play an important role in sheet metal forming analysis, since the overall material responses at macroscopic engineering scales, e.g. formability and anisotropy, are strongly influenced by microstructural properties, such as grain size and crystal orientations (texture). In the present report, multiscale analysis on deep drawing of dual-phase steels is performed using an efficient grain cluster-based homogenization scheme. The homogenization scheme, called relaxed grain cluster (RGC), is based on a generalization of the grain cluster concept, where a (representative) volume element consists of p  ×  q  ×  r (hexahedral) grains. In this scheme, variation of the strain or deformation of individual grains is taken into account through the, so-called, interface relaxation, which is formulated within an energy minimization framework. An interfacial penalty term is introduced into the energy minimization framework in order to account for the effects of grain boundaries. The grain cluster-based homogenization scheme has been implemented and incorporated into the advanced material simulation platform DAMASK, which purposes to bridge the macroscale boundary value problems associated with deep drawing analysis to the micromechanical constitutive law, e.g. crystal plasticity model. Standard Lankford anisotropy tests are performed to validate the model parameters prior to the deep drawing analysis. Model predictions for the deep drawing simulations are analyzed and compared to the corresponding experimental data. The result shows that the predictions of the model are in a very good agreement with the experimental measurement.

  10. Security analysis and enhancements of an effective biometric-based remote user authentication scheme using smart cards.

    PubMed

    An, Younghwa

    2012-01-01

    Recently, many biometrics-based user authentication schemes using smart cards have been proposed to improve the security weaknesses in user authentication system. In 2011, Das proposed an efficient biometric-based remote user authentication scheme using smart cards that can provide strong authentication and mutual authentication. In this paper, we analyze the security of Das's authentication scheme, and we have shown that Das's authentication scheme is still insecure against the various attacks. Also, we proposed the enhanced scheme to remove these security problems of Das's authentication scheme, even if the secret information stored in the smart card is revealed to an attacker. As a result of security analysis, we can see that the enhanced scheme is secure against the user impersonation attack, the server masquerading attack, the password guessing attack, and the insider attack and provides mutual authentication between the user and the server. PMID:22899887

  11. Exact density functional and wave function embedding schemes based on orbital localization

    NASA Astrophysics Data System (ADS)

    Hégely, Bence; Nagy, Péter R.; Ferenczy, György G.; Kállay, Mihály

    2016-08-01

    Exact schemes for the embedding of density functional theory (DFT) and wave function theory (WFT) methods into lower-level DFT or WFT approaches are introduced utilizing orbital localization. First, a simple modification of the projector-based embedding scheme of Manby and co-workers [J. Chem. Phys. 140, 18A507 (2014)] is proposed. We also use localized orbitals to partition the system, but instead of augmenting the Fock operator with a somewhat arbitrary level-shift projector we solve the Huzinaga-equation, which strictly enforces the Pauli exclusion principle. Second, the embedding of WFT methods in local correlation approaches is studied. Since the latter methods split up the system into local domains, very simple embedding theories can be defined if the domains of the active subsystem and the environment are treated at a different level. The considered embedding schemes are benchmarked for reaction energies and compared to quantum mechanics (QM)/molecular mechanics (MM) and vacuum embedding. We conclude that for DFT-in-DFT embedding, the Huzinaga-equation-based scheme is more efficient than the other approaches, but QM/MM or even simple vacuum embedding is still competitive in particular cases. Concerning the embedding of wave function methods, the clear winner is the embedding of WFT into low-level local correlation approaches, and WFT-in-DFT embedding can only be more advantageous if a non-hybrid density functional is employed.

  12. Best tree wavelet packet transform based copyright protection scheme for digital images

    NASA Astrophysics Data System (ADS)

    Rawat, Sanjay; Raman, Balasubramanian

    2012-05-01

    In this paper, a dual watermarking scheme based on discrete wavelet transform (DWT), wavelet packet transform (WPT) with best tree, and singular value decomposition (SVD) is proposed. In our algorithm, the cover image is sub-sampled into four sub-images and then two sub-images, having the highest sum of singular values are selected. Two different gray scale images are embedded in the selected sub-images. For embedding first watermark, one of the selected sub-image is decomposed via WPT. The entropy based algorithm is adopted to find the best tree of WPT. Watermark is embedded in all frequency sub-bands of the best tree. For embedding second watermark, l-level discrete wavelet transform (DWT) is performed on the second selected sub-image. The watermark is embedded by modifying the singular values of the transformed image. To enhance the security of the scheme, Zig-Zag scan in applied on the second watermark before embedding. The robustness of the proposed scheme is demonstrated through a series of attack simulations. Experimental results demonstrate that the proposed scheme has good perceptual invisibility and is also robust against various image processing operations, geometric attacks and JPEG Compression.

  13. PGC demodulating scheme based on CORDIC algorithm for interferometric optical fiber sensor

    NASA Astrophysics Data System (ADS)

    Jing, Zhenguo; Zhang, Min; Wang, Liwei; Yin, Kai; Liao, Yanbiao

    2007-11-01

    One important advantage of interferometric optical fiber sensor is high sensitivity. The development of the interferometric optical fiber sensor is partly restricted with the demodulating technique. Because of advantages such as high sensitivity, high dynamic range, and good linearity, PGC (Phase Generated Carrier) demodulating scheme is widely applied for interferometric optical fiber sensor now. In this paper, an arctangent approach of the PGC demodulating scheme is introduced. CORDIC (Coordinate Rotation Digital Computer) algorithm is used to realize the arctangent function. CORDIC algorithm is a method for computing elementary functions using minimal hardware such as shifts, adds/subs and compares. CORDIC algorithm works by rotating the coordinate system through constant angles until the angle is reduces to zero. The angle offsets are selected such that the operations on X and Y are only shifts and adds. This method will lead in less complexity and higher accuracy. Since digital signal processing technology has achieved great development, especially the appearances of high speed processors such as FPGA and DSP, PGC demodulating scheme based on CORDIC algorithm is implemented conveniently. The experiments are carried out to verify the PGC demodulating scheme based on CORDIC algorithm.

  14. Secure biometric image sensor and authentication scheme based on compressed sensing.

    PubMed

    Suzuki, Hiroyuki; Suzuki, Masamichi; Urabe, Takuya; Obi, Takashi; Yamaguchi, Masahiro; Ohyama, Nagaaki

    2013-11-20

    It is important to ensure the security of biometric authentication information, because its leakage causes serious risks, such as replay attacks using the stolen biometric data, and also because it is almost impossible to replace raw biometric information. In this paper, we propose a secure biometric authentication scheme that protects such information by employing an optical data ciphering technique based on compressed sensing. The proposed scheme is based on two-factor authentication, the biometric information being supplemented by secret information that is used as a random seed for a cipher key. In this scheme, a biometric image is optically encrypted at the time of image capture, and a pair of restored biometric images for enrollment and verification are verified in the authentication server. If any of the biometric information is exposed to risk, it can be reenrolled by changing the secret information. Through numerical experiments, we confirm that finger vein images can be restored from the compressed sensing measurement data. We also present results that verify the accuracy of the scheme. PMID:24513773

  15. Authentication and data hiding using a hybrid ROI-based watermarking scheme for DICOM images.

    PubMed

    Al-Qershi, Osamah M; Khoo, Bee Ee

    2011-02-01

    Authenticating medical images using watermarking techniques has become a very popular area of research, and some works in this area have been reported worldwide recently. Besides authentication, many data-hiding techniques have been proposed to conceal patient's data into medical images aiming to reduce the cost needed to store data and the time needed to transmit data when required. In this paper, we present a new hybrid watermarking scheme for DICOM images. In our scheme, two well-known techniques are combined to gain the advantages of both and fulfill the requirements of authentication and data hiding. The scheme divides the images into two parts, the region of interest (ROI) and the region of non-interest (RONI). Patient's data are embedded into ROI using a reversible technique based on difference expansion, while tamper detection and recovery data are embedded into RONI using a robust technique based on discrete wavelet transform. The experimental results show the ability of hiding patient's data with a very good visual quality, while ROI, the most important area for diagnosis, is retrieved exactly at the receiver side. The scheme also shows some robustness against certain levels of salt and pepper and cropping noise. PMID:19937363

  16. Where does the carbon go? A model–data intercomparison of vegetation carbon allocation and turnover processes at two temperate forest free-air CO2 enrichment sites

    PubMed Central

    De Kauwe, Martin G; Medlyn, Belinda E; Zaehle, Sönke; Walker, Anthony P; Dietze, Michael C; Wang, Ying-Ping; Luo, Yiqi; Jain, Atul K; El-Masri, Bassil; Hickler, Thomas; Wårlind, David; Weng, Ensheng; Parton, William J; Thornton, Peter E; Wang, Shusen; Prentice, I Colin; Asao, Shinichi; Smith, Benjamin; McCarthy, Heather R; Iversen, Colleen M; Hanson, Paul J; Warren, Jeffrey M; Oren, Ram; Norby, Richard J

    2014-01-01

    Elevated atmospheric CO2 concentration (eCO2) has the potential to increase vegetation carbon storage if increased net primary production causes increased long-lived biomass. Model predictions of eCO2 effects on vegetation carbon storage depend on how allocation and turnover processes are represented. We used data from two temperate forest free-air CO2 enrichment (FACE) experiments to evaluate representations of allocation and turnover in 11 ecosystem models. Observed eCO2 effects on allocation were dynamic. Allocation schemes based on functional relationships among biomass fractions that vary with resource availability were best able to capture the general features of the observations. Allocation schemes based on constant fractions or resource limitations performed less well, with some models having unintended outcomes. Few models represent turnover processes mechanistically and there was wide variation in predictions of tissue lifespan. Consequently, models did not perform well at predicting eCO2 effects on vegetation carbon storage. Our recommendations to reduce uncertainty include: use of allocation schemes constrained by biomass fractions; careful testing of allocation schemes; and synthesis of allocation and turnover data in terms of model parameters. Data from intensively studied ecosystem manipulation experiments are invaluable for constraining models and we recommend that such experiments should attempt to fully quantify carbon, water and nutrient budgets. PMID:24844873

  17. Where does the carbon go? A model-data intercomparison of vegetation carbon allocation and turnover processes at two temperate forest free-air CO2 enrichment sites.

    PubMed

    De Kauwe, Martin G; Medlyn, Belinda E; Zaehle, Sönke; Walker, Anthony P; Dietze, Michael C; Wang, Ying-Ping; Luo, Yiqi; Jain, Atul K; El-Masri, Bassil; Hickler, Thomas; Wårlind, David; Weng, Ensheng; Parton, William J; Thornton, Peter E; Wang, Shusen; Prentice, I Colin; Asao, Shinichi; Smith, Benjamin; McCarthy, Heather R; Iversen, Colleen M; Hanson, Paul J; Warren, Jeffrey M; Oren, Ram; Norby, Richard J

    2014-08-01

    Elevated atmospheric CO2 concentration (eCO2) has the potential to increase vegetation carbon storage if increased net primary production causes increased long-lived biomass. Model predictions of eCO2 effects on vegetation carbon storage depend on how allocation and turnover processes are represented. We used data from two temperate forest free-air CO2 enrichment (FACE) experiments to evaluate representations of allocation and turnover in 11 ecosystem models. Observed eCO2 effects on allocation were dynamic. Allocation schemes based on functional relationships among biomass fractions that vary with resource availability were best able to capture the general features of the observations. Allocation schemes based on constant fractions or resource limitations performed less well, with some models having unintended outcomes. Few models represent turnover processes mechanistically and there was wide variation in predictions of tissue lifespan. Consequently, models did not perform well at predicting eCO2 effects on vegetation carbon storage. Our recommendations to reduce uncertainty include: use of allocation schemes constrained by biomass fractions; careful testing of allocation schemes; and synthesis of allocation and turnover data in terms of model parameters. Data from intensively studied ecosystem manipulation experiments are invaluable for constraining models and we recommend that such experiments should attempt to fully quantify carbon, water and nutrient budgets. PMID:24844873

  18. Minimum cost maximum flow algorithm for upstream bandwidth allocation in OFDMA passive optical networks

    NASA Astrophysics Data System (ADS)

    Wu, Yating; Kuang, Bin; Wang, Tao; Zhang, Qianwu; Wang, Min

    2015-12-01

    This paper presents a minimum cost maximum flow (MCMF) based upstream bandwidth allocation algorithm, which supports differentiated QoS for orthogonal frequency division multiple access passive optical networks (OFDMA-PONs). We define a utility function as the metric to characterize the satisfaction degree of an ONU on the obtained bandwidth. The bandwidth allocation problem is then formulated as maximizing the sum of the weighted total utility functions of all ONUs. By constructing a flow network graph, we obtain the optimized bandwidth allocation using the MCMF algorithm. Simulation results show that the proposed scheme improves the performance in terms of mean packet delay, packet loss ratio and throughput.

  19. Design of a Classification Scheme for Fiction Based on an Analysis of Actual User-Librarian Communication, and Use of the Scheme for Control of Librarian's Search Strategies.

    ERIC Educational Resources Information Center

    Pejtersen, Annelise Mark

    Because the general alphabetic arrangement of fiction in libraries is of little use to the ordinary reader, whose criteria for selecting books often relates to book content, a multi-dimensional and inexclusive fiction classification scheme was developed as a model for both book description and search strategy. Based on analysis of 160 actual…

  20. Statistical mechanics of competitive resource allocation using agent-based models

    NASA Astrophysics Data System (ADS)

    Chakraborti, Anirban; Challet, Damien; Chatterjee, Arnab; Marsili, Matteo; Zhang, Yi-Cheng; Chakrabarti, Bikas K.

    2015-01-01

    Demand outstrips available resources in most situations, which gives rise to competition, interaction and learning. In this article, we review a broad spectrum of multi-agent models of competition (El Farol Bar problem, Minority Game, Kolkata Paise Restaurant problem, Stable marriage problem, Parking space problem and others) and the methods used to understand them analytically. We emphasize the power of concepts and tools from statistical mechanics to understand and explain fully collective phenomena such as phase transitions and long memory, and the mapping between agent heterogeneity and physical disorder. As these methods can be applied to any large-scale model of competitive resource allocation made up of heterogeneous adaptive agent with non-linear interaction, they provide a prospective unifying paradigm for many scientific disciplines.

  1. 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. PMID:23553734

  2. Optimizing insecticide allocation strategies based on houses and livestock shelters for visceral leishmaniasis control in Bihar, India.

    PubMed

    Gorahava, Kaushik K; Rosenberger, Jay M; Mubayi, Anuj

    2015-07-01

    Visceral leishmaniasis (VL) is the most deadly form of the leishmaniasis family of diseases, which affects numerous developing countries. The Indian state of Bihar has the highest prevalence and mortality rate of VL in the world. Insecticide spraying is believed to be an effective vector control program for controlling the spread of VL in Bihar; however, it is expensive and less effective if not implemented systematically. This study develops and analyzes a novel optimization model for VL control in Bihar that identifies an optimal (best possible) allocation of chosen insecticide (dichlorodiphenyltrichloroethane [DDT] or deltamethrin) based on the sizes of human and cattle populations in the region. The model maximizes the insecticide-induced sandfly death rate in human and cattle dwellings while staying within the current state budget for VL vector control efforts. The model results suggest that deltamethrin might not be a good replacement for DDT because the insecticide-induced sandfly deaths are 3.72 times more in case of DDT even after 90 days post spray. Different insecticide allocation strategies between the two types of sites (houses and cattle sheds) are suggested based on the state VL-control budget and have a direct implication on VL elimination efforts in a resource-limited region. PMID:25940194

  3. Optimum and Suboptimum Code Allocation for Peak Power Reduction in Down-Link MC CDMA

    NASA Astrophysics Data System (ADS)

    Choi, Kwonhue; Jin, Jiyu

    We develop an optimum code allocation scheme by investigating the peak to average power ratio (PAPR) characteristic of a down-link multi-carrier (MC)-CDMA system using Walsh-Hadamard code. It is shown that PAPR of a MC-CDMA system is highly dependent upon the selection of code combination. Based on this fact, we develop the allocation method which minimizes PAPR according to the number of active users. In addition, an efficient suboptimum code combination search scheme is also proposed for near minimum PAPR.

  4. Distributed Multi-Agent-Based Protection Scheme for Transient Stability Enhancement in Power Systems

    NASA Astrophysics Data System (ADS)

    Rahman, M. S.; Mahmud, M. A.; Pota, H. R.; Hossain, M. J.; Orchi, T. F.

    2015-04-01

    This paper presents a new distributed agent-based scheme to enhance the transient stability of power systems by maintaining phase angle cohesiveness of interconnected generators through proper relay coordination with critical clearing time (CCT) information. In this distributed multi-agent infrastructure, intelligent agents represent various physical device models to provide dynamic information and energy flow among different physical processes of power systems. The agents can communicate with each other in a distributed manner with a final aim to control circuit breakers (CBs) with CCT information as this is the key issue for maintaining and enhancing the transient stability of power systems. The performance of the proposed scheme is evaluated on a standard IEEE 39-bus New England benchmark system under different large disturbances such as three-phase short-circuit faults and changes in loads within the systems. From the simulation results, it is found that the proposed scheme significantly enhances the transient stability of power systems as compared to a conventional scheme of static CB operation.

  5. A Secret 3D Model Sharing Scheme with Reversible Data Hiding Based on Space Subdivision

    NASA Astrophysics Data System (ADS)

    Tsai, Yuan-Yu

    2016-03-01

    Secret sharing is a highly relevant research field, and its application to 2D images has been thoroughly studied. However, secret sharing schemes have not kept pace with the advances of 3D models. With the rapid development of 3D multimedia techniques, extending the application of secret sharing schemes to 3D models has become necessary. In this study, an innovative secret 3D model sharing scheme for point geometries based on space subdivision is proposed. Each point in the secret point geometry is first encoded into a series of integer values that fall within [0, p - 1], where p is a predefined prime number. The share values are derived by substituting the specified integer values for all coefficients of the sharing polynomial. The surface reconstruction and the sampling concepts are then integrated to derive a cover model with sufficient model complexity for each participant. Finally, each participant has a separate 3D stego model with embedded share values. Experimental results show that the proposed technique supports reversible data hiding and the share values have higher levels of privacy and improved robustness. This technique is simple and has proven to be a feasible secret 3D model sharing scheme.

  6. 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

  7. Energy-Aware Multipath Routing Scheme Based on Particle Swarm Optimization in Mobile Ad Hoc Networks

    PubMed Central

    Robinson, Y. Harold; Rajaram, M.

    2015-01-01

    Mobile ad hoc network (MANET) is a collection of autonomous mobile nodes forming an ad hoc network without fixed infrastructure. Dynamic topology property of MANET may degrade the performance of the network. However, multipath selection is a great challenging task to improve the network lifetime. We proposed an energy-aware multipath routing scheme based on particle swarm optimization (EMPSO) that uses continuous time recurrent neural network (CTRNN) to solve optimization problems. CTRNN finds the optimal loop-free paths to solve link disjoint paths in a MANET. The CTRNN is used as an optimum path selection technique that produces a set of optimal paths between source and destination. In CTRNN, particle swarm optimization (PSO) method is primly used for training the RNN. The proposed scheme uses the reliability measures such as transmission cost, energy factor, and the optimal traffic ratio between source and destination to increase routing performance. In this scheme, optimal loop-free paths can be found using PSO to seek better link quality nodes in route discovery phase. PSO optimizes a problem by iteratively trying to get a better solution with regard to a measure of quality. The proposed scheme discovers multiple loop-free paths by using PSO technique. PMID:26819966

  8. A dispersion minimizing scheme for the 3-D Helmholtz equation based on ray theory

    NASA Astrophysics Data System (ADS)

    Stolk, Christiaan C.

    2016-06-01

    We develop a new dispersion minimizing compact finite difference scheme for the Helmholtz equation in 2 and 3 dimensions. The scheme is based on a newly developed ray theory for difference equations. A discrete Helmholtz operator and a discrete operator to be applied to the source and the wavefields are constructed. Their coefficients are piecewise polynomial functions of hk, chosen such that phase and amplitude errors are minimal. The phase errors of the scheme are very small, approximately as small as those of the 2-D quasi-stabilized FEM method and substantially smaller than those of alternatives in 3-D, assuming the same number of gridpoints per wavelength is used. In numerical experiments, accurate solutions are obtained in constant and smoothly varying media using meshes with only five to six points per wavelength and wave propagation over hundreds of wavelengths. When used as a coarse level discretization in a multigrid method the scheme can even be used with down to three points per wavelength. Tests on 3-D examples with up to 108 degrees of freedom show that with a recently developed hybrid solver, the use of coarser meshes can lead to corresponding savings in computation time, resulting in good simulation times compared to the literature.

  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

    2016-01-01

    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

  10. Energy-Aware Multipath Routing Scheme Based on Particle Swarm Optimization in Mobile Ad Hoc Networks.

    PubMed

    Robinson, Y Harold; Rajaram, M

    2015-01-01

    Mobile ad hoc network (MANET) is a collection of autonomous mobile nodes forming an ad hoc network without fixed infrastructure. Dynamic topology property of MANET may degrade the performance of the network. However, multipath selection is a great challenging task to improve the network lifetime. We proposed an energy-aware multipath routing scheme based on particle swarm optimization (EMPSO) that uses continuous time recurrent neural network (CTRNN) to solve optimization problems. CTRNN finds the optimal loop-free paths to solve link disjoint paths in a MANET. The CTRNN is used as an optimum path selection technique that produces a set of optimal paths between source and destination. In CTRNN, particle swarm optimization (PSO) method is primly used for training the RNN. The proposed scheme uses the reliability measures such as transmission cost, energy factor, and the optimal traffic ratio between source and destination to increase routing performance. In this scheme, optimal loop-free paths can be found using PSO to seek better link quality nodes in route discovery phase. PSO optimizes a problem by iteratively trying to get a better solution with regard to a measure of quality. The proposed scheme discovers multiple loop-free paths by using PSO technique. PMID:26819966

  11. Hierarchical Control Scheme for Improving Transient Voltage Recovery of a DFIG-Based WPP

    SciTech Connect

    Kim, Jinho; Muljadi, Eduard; Kang, Yong Cheol

    2015-06-05

    Modern grid codes require that wind power plants (WPPs) inject reactive power according to the voltage dip at a point of interconnection (POI). This requirement helps to support a POI voltage during a fault. However, if a fault is cleared, the POI and wind turbine generator (WTG) voltages are likely to exceed acceptable levels unless the WPP reduces the injected reactive power quickly. This might deteriorate the stability of a grid by allowing the disconnection of WTGs to avoid any damage. This paper proposes a hierarchical control scheme of a doubly-fed induction generator (DFIG)-based WPP. The proposed scheme aims to improve the reactive power injecting capability during the fault and suppress the overvoltage after the fault clearance. To achieve the former, an adaptive reactive power-to-voltage scheme is implemented in each DFIG controller so that a DFIG with a larger reactive power capability will inject more reactive power. To achieve the latter, a washout filter is used to capture a high frequency component contained in the WPP voltage, which is used to remove the accumulated values in the proportional-integral controllers. Test results indicate that the scheme successfully supports the grid voltage during the fault, and recovers WPP voltages without exceeding the limit after the fault clearance.

  12. An Improved and Secure Biometric Authentication Scheme for Telecare Medicine Information Systems Based on Elliptic Curve Cryptography.

    PubMed

    Chaudhry, Shehzad Ashraf; Mahmood, Khalid; Naqvi, Husnain; Khan, Muhammad Khurram

    2015-11-01

    Telecare medicine information system (TMIS) offers the patients convenient and expedite healthcare services remotely anywhere. Patient security and privacy has emerged as key issues during remote access because of underlying open architecture. An authentication scheme can verify patient's as well as TMIS server's legitimacy during remote healthcare services. To achieve security and privacy a number of authentication schemes have been proposed. Very recently Lu et al. (J. Med. Syst. 39(3):1-8, 2015) proposed a biometric based three factor authentication scheme for TMIS to confiscate the vulnerabilities of Arshad et al.'s (J. Med. Syst. 38(12):136, 2014) scheme. Further, they emphasized the robustness of their scheme against several attacks. However, in this paper we establish that Lu et al.'s scheme is vulnerable to numerous attacks including (1) Patient anonymity violation attack, (2) Patient impersonation attack, and (3) TMIS server impersonation attack. Furthermore, their scheme does not provide patient untraceability. We then, propose an improvement of Lu et al.'s scheme. We have analyzed the security of improved scheme using popular automated tool ProVerif. The proposed scheme while retaining the plusses of Lu et al.'s scheme is also robust against known attacks. PMID:26399937

  13. Initial ranging scheme based on interpolated Zadoff-Chu sequences for OFDMA-PON.

    PubMed

    Razmtouz, Ali; Habel, Kai; Kottke, Christoph; Ruprecht, Christian; Rosenkranz, Werner

    2014-02-10

    Initial access to passive optical networks (PONs) requires upstream (US) synchronization of multiple optical network units (ONUs). We propose a low-complexity scheme for orthogonal frequency division multiple access (OFDMA) based PONs and demonstrate it experimentally. The scheme is based on interpolated Zadoff-Chu sequences, to synchronize the signal of each ONU arriving at the optical line terminal (OLT). Our experimental test bed consists of 4 colorless ONUs seeded by a single laser located at the OLT. Thermal expansion of a fiber is utilized to emulate a dynamic time drift in the demodulation-window positioning of OLT. The detected individual offsets at the OLT are fed back to the ONUs and are compensated at every data frame transmission. In this way, both inter carrier interference (ICI) and inter symbol interference (ISI) remain below acceptable levels. PMID:24663658

  14. Actuator fault tolerant multi-controller scheme using set separation based diagnosis

    NASA Astrophysics Data System (ADS)

    Seron, María M.; De Doná, José A.

    2010-11-01

    We present a fault tolerant control strategy based on a new principle for actuator fault diagnosis. The scheme employs a standard bank of observers which match the different fault situations that can occur in the plant. Each of these observers has an associated estimation error with distinctive dynamics when an estimator matches the current fault situation of the plant. Based on the information from each observer, a fault detection and isolation (FDI) module is able to reconfigure the control loop by selecting the appropriate control law from a bank of controllers, each of them designed to stabilise and achieve reference tracking for one of the given fault models. The main contribution of this article is to propose a new FDI principle which exploits the separation of sets that characterise healthy system operation from sets that characterise transitions from healthy to faulty behaviour. The new principle allows to provide pre-checkable conditions for guaranteed fault tolerance of the overall multi-controller scheme.

  15. Image communication scheme based on dynamic visual cryptography and computer generated holography

    NASA Astrophysics Data System (ADS)

    Palevicius, Paulius; Ragulskis, Minvydas

    2015-01-01

    Computer generated holograms are often exploited to implement optical encryption schemes. This paper proposes the integration of dynamic visual cryptography (an optical technique based on the interplay of visual cryptography and time-averaging geometric moiré) with Gerchberg-Saxton algorithm. A stochastic moiré grating is used to embed the secret into a single cover image. The secret can be visually decoded by a naked eye if only the amplitude of harmonic oscillations corresponds to an accurately preselected value. The proposed visual image encryption scheme is based on computer generated holography, optical time-averaging moiré and principles of dynamic visual cryptography. Dynamic visual cryptography is used both for the initial encryption of the secret image and for the final decryption. Phase data of the encrypted image are computed by using Gerchberg-Saxton algorithm. The optical image is decrypted using the computationally reconstructed field of amplitudes.

  16. A magnetic resonance spectroscopy driven initialization scheme for active shape model based prostate segmentation.

    PubMed

    Toth, Robert; Tiwari, Pallavi; Rosen, Mark; Reed, Galen; Kurhanewicz, John; Kalyanpur, Arjun; Pungavkar, Sona; Madabhushi, Anant

    2011-04-01

    Segmentation of the prostate boundary on clinical images is useful in a large number of applications including calculation of prostate volume pre- and post-treatment, to detect extra-capsular spread, and for creating patient-specific anatomical models. Manual segmentation of the prostate boundary is, however, time consuming and subject to inter- and intra-reader variability. T2-weighted (T2-w) magnetic resonance (MR) structural imaging (MRI) and MR spectroscopy (MRS) have recently emerged as promising modalities for detection of prostate cancer in vivo. MRS data consists of spectral signals measuring relative metabolic concentrations, and the metavoxels near the prostate have distinct spectral signals from metavoxels outside the prostate. Active Shape Models (ASM's) have become very popular segmentation methods for biomedical imagery. However, ASMs require careful initialization and are extremely sensitive to model initialization. The primary contribution of this paper is a scheme to automatically initialize an ASM for prostate segmentation on endorectal in vivo multi-protocol MRI via automated identification of MR spectra that lie within the prostate. A replicated clustering scheme is employed to distinguish prostatic from extra-prostatic MR spectra in the midgland. The spatial locations of the prostate spectra so identified are used as the initial ROI for a 2D ASM. The midgland initializations are used to define a ROI that is then scaled in 3D to cover the base and apex of the prostate. A multi-feature ASM employing statistical texture features is then used to drive the edge detection instead of just image intensity information alone. Quantitative comparison with another recent ASM initialization method by Cosio showed that our scheme resulted in a superior average segmentation performance on a total of 388 2D MRI sections obtained from 32 3D endorectal in vivo patient studies. Initialization of a 2D ASM via our MRS-based clustering scheme resulted in an average

  17. A Learning Based Fiducial-driven Registration Scheme for Evaluating Laser Ablation Changes in Neurological Disorders

    PubMed Central

    Wan, Tao; Bloch, B.Nicolas; Danish, Shabbar; Madabhushi, Anant

    2014-01-01

    In this work, we present a novel learning based fiducial driven registration (LeFiR) scheme which utilizes a point matching technique to identify the optimal configuration of landmarks to better recover deformation between a target and a moving image. Moreover, we employ the LeFiR scheme to model the localized nature of deformation introduced by a new treatment modality - laser induced interstitial thermal therapy (LITT) for treating neurological disorders. Magnetic resonance (MR) guided LITT has recently emerged as a minimally invasive alternative to craniotomy for local treatment of brain diseases (such as glioblastoma multiforme (GBM), epilepsy). However, LITT is currently only practised as an investigational procedure world-wide due to lack of data on longer term patient outcome following LITT. There is thus a need to quantitatively evaluate treatment related changes between post- and pre-LITT in terms of MR imaging markers. In order to validate LeFiR, we tested the scheme on a synthetic brain dataset (SBD) and in two real clinical scenarios for treating GBM and epilepsy with LITT. Four experiments under different deformation profiles simulating localized ablation effects of LITT on MRI were conducted on 286 pairs of SBD images. The training landmark configurations were obtained through 2000 iterations of registration where the points with consistently best registration performance were selected. The estimated landmarks greatly improved the quality metrics compared to a uniform grid (UniG) placement scheme, a speeded-up robust features (SURF) based method, and a scale-invariant feature transform (SIFT) based method as well as a generic free-form deformation (FFD) approach. The LeFiR method achieved average 90% improvement in recovering the local deformation compared to 82% for the uniform grid placement, 62% for the SURF based approach, and 16% for the generic FFD approach. On the real GBM and epilepsy data, the quantitative results showed that Le

  18. A novel codification scheme based on the "VITAL" and "DICOM" Standards for telemedicine applications.

    PubMed

    Anagnostaki, Anthoula P; Pavlopoulos, Sotiris; Kyriakou, Efthivoulos; Koutsouris, Dimitris

    2002-12-01

    The field of interest discussed in this study is a novel codification scheme for (vital signs) medical device communication and patient monitoring data interchange, into the context of effective home care service provisioning. With medical technology having developed in isolation and major manufacturers developing their own proprietary communication protocols, which preclude connection to devices from different manufacturers, and with healthcare trends having evolved, pointing to primary care, telecare and home care monitoring, there is an increasing need for technical standardization in healthcare environments and the development of protocols that enable communication in a structured and open way. In this study, a novel codification scheme has been developed, based on two healthcare informatics standards, the VITAL and DICOM Sup. 30, in addressing the robust interchange of waveform and medical data for a home care application. Based on this scheme, we created a real-time facility, consisting of a base unit and a telemedicine (mobile) unit, that enables home telemonitoring, by installing the telemedicine unit at the patient's home while the base unit remains at the physician's office or hospital. The system allows the transmission of vital biosignals (3-lead ECG, pulse rate, blood pressure and SpO2) of the patient. This paper presents an object-oriented design with unified modeling language (UML) of a class hierarchy for exchanging the acquired medical data and performing alert management, and investigates the applicability of the proposed scheme into a commercial patient-connected medical device, thus addressing service and functionality requirements with focus on home-care applications. The system has been validated for technical performance over several telecommunication means and for clinical validity via real patient-involved pilot trials. PMID:12542235

  19. An Image Encryption Scheme Based on Lorenz System for Low Profile Applications

    NASA Astrophysics Data System (ADS)

    Anees, Amir

    2015-09-01

    Advanced encryption standard being a benchmark for encryption is very ideal for digital images encryption for its security reasons but might not be effective for low profile applications due to its high computational and hardware complexity. In this paper, we presents a robust image encryption scheme for these types of applications based on chaotic sequences of Lorenz system, also ensuring the system security as well. The security strength is evident from the results of statistical and key analysis done in this paper.

  20. A Hash Based Remote User Authentication and Authenticated Key Agreement Scheme for the Integrated EPR Information System.

    PubMed

    Li, Chun-Ta; Weng, Chi-Yao; Lee, Cheng-Chi; Wang, Chun-Cheng

    2015-11-01

    To protect patient privacy and ensure authorized access to remote medical services, many remote user authentication schemes for the integrated electronic patient record (EPR) information system have been proposed in the literature. In a recent paper, Das proposed a hash based remote user authentication scheme using passwords and smart cards for the integrated EPR information system, and claimed that the proposed scheme could resist various passive and active attacks. However, in this paper, we found that Das's authentication scheme is still vulnerable to modification and user duplication attacks. Thereafter we propose a secure and efficient authentication scheme for the integrated EPR information system based on lightweight hash function and bitwise exclusive-or (XOR) operations. The security proof and performance analysis show our new scheme is well-suited to adoption in remote medical healthcare services. PMID:26349803

  1. Exponential Arithmetic Based Self-Healing Group Key Distribution Scheme with Backward Secrecy under the Resource-Constrained Wireless Networks.

    PubMed

    Guo, Hua; Zheng, Yandong; Zhang, Xiyong; Li, Zhoujun

    2016-01-01

    In resource-constrained wireless networks, resources such as storage space and communication bandwidth are limited. To guarantee secure communication in resource-constrained wireless networks, group keys should be distributed to users. The self-healing group key distribution (SGKD) scheme is a promising cryptographic tool, which can be used to distribute and update the group key for the secure group communication over unreliable wireless networks. Among all known SGKD schemes, exponential arithmetic based SGKD (E-SGKD) schemes reduce the storage overhead to constant, thus is suitable for the the resource-constrained wireless networks. In this paper, we provide a new mechanism to achieve E-SGKD schemes with backward secrecy. We first propose a basic E-SGKD scheme based on a known polynomial-based SGKD, where it has optimal storage overhead while having no backward secrecy. To obtain the backward secrecy and reduce the communication overhead, we introduce a novel approach for message broadcasting and self-healing. Compared with other E-SGKD schemes, our new E-SGKD scheme has the optimal storage overhead, high communication efficiency and satisfactory security. The simulation results in Zigbee-based networks show that the proposed scheme is suitable for the resource-restrained wireless networks. Finally, we show the application of our proposed scheme. PMID:27136550

  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. PMID:25900328

  3. Exponential Arithmetic Based Self-Healing Group Key Distribution Scheme with Backward Secrecy under the Resource-Constrained Wireless Networks

    PubMed Central

    Guo, Hua; Zheng, Yandong; Zhang, Xiyong; Li, Zhoujun

    2016-01-01

    In resource-constrained wireless networks, resources such as storage space and communication bandwidth are limited. To guarantee secure communication in resource-constrained wireless networks, group keys should be distributed to users. The self-healing group key distribution (SGKD) scheme is a promising cryptographic tool, which can be used to distribute and update the group key for the secure group communication over unreliable wireless networks. Among all known SGKD schemes, exponential arithmetic based SGKD (E-SGKD) schemes reduce the storage overhead to constant, thus is suitable for the the resource-constrained wireless networks. In this paper, we provide a new mechanism to achieve E-SGKD schemes with backward secrecy. We first propose a basic E-SGKD scheme based on a known polynomial-based SGKD, where it has optimal storage overhead while having no backward secrecy. To obtain the backward secrecy and reduce the communication overhead, we introduce a novel approach for message broadcasting and self-healing. Compared with other E-SGKD schemes, our new E-SGKD scheme has the optimal storage overhead, high communication efficiency and satisfactory security. The simulation results in Zigbee-based networks show that the proposed scheme is suitable for the resource-restrained wireless networks. Finally, we show the application of our proposed scheme. PMID:27136550

  4. Universal health coverage in Latin American countries: how to improve solidarity-based schemes.

    PubMed

    Titelman, Daniel; Cetrángolo, Oscar; Acosta, Olga Lucía

    2015-04-01

    In this Health Policy we examine the association between the financing structure of health systems and universal health coverage. Latin American health systems encompass a wide range of financial sources, which translate into different solidarity-based schemes that combine contributory (payroll taxes) and non-contributory (general taxes) sources of financing. To move towards universal health coverage, solidarity-based schemes must heavily rely on countries' capacity to increase public expenditure in health. Improvement of solidarity-based schemes will need the expansion of mandatory universal insurance systems and strengthening of the public sector including increased fiscal expenditure. These actions demand a new model to integrate different sources of health-sector financing, including general tax revenue, social security contributions, and private expenditure. The extent of integration achieved among these sources will be the main determinant of solidarity and universal health coverage. The basic challenges for improvement of universal health coverage are not only to spend more on health, but also to reduce the proportion of out-of-pocket spending, which will need increased fiscal resources. PMID:25458734

  5. An Adaptive Handover Prediction Scheme for Seamless Mobility Based Wireless Networks

    PubMed Central

    Safa Sadiq, Ali; Fisal, Norsheila Binti; Ghafoor, Kayhan Zrar; Lloret, Jaime

    2014-01-01

    We propose an adaptive handover prediction (AHP) scheme for seamless mobility based wireless networks. That is, the AHP scheme incorporates fuzzy logic with AP prediction process in order to lend cognitive capability to handover decision making. Selection metrics, including received signal strength, mobile node relative direction towards the access points in the vicinity, and access point load, are collected and considered inputs of the fuzzy decision making system in order to select the best preferable AP around WLANs. The obtained handover decision which is based on the calculated quality cost using fuzzy inference system is also based on adaptable coefficients instead of fixed coefficients. In other words, the mean and the standard deviation of the normalized network prediction metrics of fuzzy inference system, which are collected from available WLANs are obtained adaptively. Accordingly, they are applied as statistical information to adjust or adapt the coefficients of membership functions. In addition, we propose an adjustable weight vector concept for input metrics in order to cope with the continuous, unpredictable variation in their membership degrees. Furthermore, handover decisions are performed in each MN independently after knowing RSS, direction toward APs, and AP load. Finally, performance evaluation of the proposed scheme shows its superiority compared with representatives of the prediction approaches. PMID:25574490

  6. Novel Image Encryption Scheme Based on Chebyshev Polynomial and Duffing Map

    PubMed Central

    2014-01-01

    We present a novel image encryption algorithm using Chebyshev polynomial based on permutation and substitution and Duffing map based on substitution. Comprehensive security analysis has been performed on the designed scheme using key space analysis, visual testing, histogram analysis, information entropy calculation, correlation coefficient analysis, differential analysis, key sensitivity test, and speed test. The study demonstrates that the proposed image encryption algorithm shows advantages of more than 10113 key space and desirable level of security based on the good statistical results and theoretical arguments. PMID:25143970

  7. Smartphone-Based Patients' Activity Recognition by Using a Self-Learning Scheme for Medical Monitoring.

    PubMed

    Guo, Junqi; Zhou, Xi; Sun, Yunchuan; Ping, Gong; Zhao, Guoxing; Li, Zhuorong

    2016-06-01

    Smartphone based activity recognition has recently received remarkable attention in various applications of mobile health such as safety monitoring, fitness tracking, and disease prediction. To achieve more accurate and simplified medical monitoring, this paper proposes a self-learning scheme for patients' activity recognition, in which a patient only needs to carry an ordinary smartphone that contains common motion sensors. After the real-time data collection though this smartphone, we preprocess the data using coordinate system transformation to eliminate phone orientation influence. A set of robust and effective features are then extracted from the preprocessed data. Because a patient may inevitably perform various unpredictable activities that have no apriori knowledge in the training dataset, we propose a self-learning activity recognition scheme. The scheme determines whether there are apriori training samples and labeled categories in training pools that well match with unpredictable activity data. If not, it automatically assembles these unpredictable samples into different clusters and gives them new category labels. These clustered samples combined with the acquired new category labels are then merged into the training dataset to reinforce recognition ability of the self-learning model. In experiments, we evaluate our scheme using the data collected from two postoperative patient volunteers, including six labeled daily activities as the initial apriori categories in the training pool. Experimental results demonstrate that the proposed self-learning scheme for activity recognition works very well for most cases. When there exist several types of unseen activities without any apriori information, the accuracy reaches above 80 % after the self-learning process converges. PMID:27106584

  8. GPU-based parallel implementation of 5-layer thermal diffusion scheme

    NASA Astrophysics Data System (ADS)

    Huang, Melin; Mielikainen, Jarno; Huang, Bormin; Huang, H.-L. A.; Goldberg, Mitchell D.

    2012-10-01

    The Weather Research and Forecasting (WRF) is a system of numerical weather prediction and atmospheric simulation with dual purposes for forecasting and research. The WRF software infrastructure consists of several components such as dynamic solvers and physical simulation modules. WRF includes several Land-Surface Models (LSMs). The LSMs use atmospheric information, the radiative and precipitation forcing from the surface layer scheme, the radiation scheme, and the microphysics/convective scheme all together with the lands state variables and land-surface properties, to provide heat and moisture fluxes over land and sea-ice points. The WRF 5-layer thermal diffusion simulation is an LSM based on the MM5 5-layer soil temperature model with an energy budget that includes radiation, sensible, and latent heat flux. The WRF LSMs are very suitable for massively parallel computation as there are no interactions among horizontal grid points. More and more scientific applications have adopted graphics processing units (GPUs) to accelerate the computing performance. This study demonstrates our GPU massively parallel computation efforts on the WRF 5-layer thermal diffusion scheme. Since this scheme is only an intermediate module of the entire WRF model, the I/O transfer does not involve in the intermediate process. Without data transfer, this module can achieve a speedup of 36x with one GPU and 108x with four GPUs as compared to a single threaded CPU processor. With CPU/GPU hybrid strategy, this module can accomplish a even higher speedup, ~114x with one GPU and ~240x with four GPUs. Meanwhile, we are seeking other approaches to improve the speeds.

  9. Performance impact of mutation operators of a subpopulation-based genetic algorithm for multi-robot task allocation problems.

    PubMed

    Liu, Chun; Kroll, Andreas

    2016-01-01

    Multi-robot task allocation determines the task sequence and distribution for a group of robots in multi-robot systems, which is one of constrained combinatorial optimization problems and more complex in case of cooperative tasks because they introduce additional spatial and temporal constraints. To solve multi-robot task allocation problems with cooperative tasks efficiently, a subpopulation-based genetic algorithm, a crossover-free genetic algorithm employing mutation operators and elitism selection in each subpopulation, is developed in this paper. Moreover, the impact of mutation operators (swap, insertion, inversion, displacement, and their various combinations) is analyzed when solving several industrial plant inspection problems. The experimental results show that: (1) the proposed genetic algorithm can obtain better solutions than the tested binary tournament genetic algorithm with partially mapped crossover; (2) inversion mutation performs better than other tested mutation operators when solving problems without cooperative tasks, and the swap-inversion combination performs better than other tested mutation operators/combinations when solving problems with cooperative tasks. As it is difficult to produce all desired effects with a single mutation operator, using multiple mutation operators (including both inversion and swap) is suggested when solving similar combinatorial optimization problems. PMID:27588254

  10. Constant time worker thread allocation via configuration caching

    DOEpatents

    Eichenberger, Alexandre E; O'Brien, John K. P.

    2014-11-04

    Mechanisms are provided for allocating threads for execution of a parallel region of code. A request for allocation of worker threads to execute the parallel region of code is received from a master thread. Cached thread allocation information identifying prior thread allocations that have been performed for the master thread are accessed. Worker threads are allocated to the master thread based on the cached thread allocation information. The parallel region of code is executed using the allocated worker threads.

  11. Application of portfolio theory to risk-based allocation of surveillance resources in animal populations.

    PubMed

    Prattley, D J; Morris, R S; Stevenson, M A; Thornton, R

    2007-09-14

    Distribution of finite levels of resources between multiple competing tasks can be a challenging problem. Resources need to be distributed across time periods and geographic locations to increase the probability of detection of a disease incursion or significant change in disease pattern. Efforts should focus primarily on areas and populations where risk factors for a given disease reach relatively high levels. In order to target resources into these areas, the overall risk level can be evaluated periodically across locations to create a dynamic national risk landscape. Methods are described to integrate the levels of various risk factors into an overall risk score for each area, to account for the certainty or variability around those measures and then to allocate surveillance resources across this risk landscape. In addition to targeting resources into high risk areas, surveillance continues in lower risk areas where there is a small yet positive chance of disease occurrence. In this paper we describe the application of portfolio theory concepts, routinely used in finance, to design surveillance portfolios for a series of examples. The appropriate level of resource investment is chosen for each disease or geographical area and time period given the degree of disease risk and uncertainty present. PMID:17509705

  12. Job Admission and Resource Allocation in Distributed Streaming Systems

    NASA Astrophysics Data System (ADS)

    Wolf, Joel; Bansal, Nikhil; Hildrum, Kirsten; Parekh, Sujay; Rajan, Deepak; Wagle, Rohit; Wu, Kun-Lung

    This paper describes a new and novel scheme for job admission and resource allocation employed by the SODA scheduler in System S. Capable of processing enormous quantities of streaming data, System S is a large-scale, distributed stream processing system designed to handle complex applications. The problem of scheduling in distributed, stream-based systems is quite unlike that in more traditional systems. And the requirements for System S, in particular, are more stringent than one might expect even in a “standard” stream-based design. For example, in System S, the offered load is expected to vastly exceed system capacity. So a careful job admission scheme is essential. The jobs in System S are essentially directed graphs, with software “processing elements” (PEs) as vertices and data streams as edges connecting the PEs. The jobs themselves are often heavily interconnected. Thus resource allocation of individual PEs must be done carefully in order to balance the flow. We describe the design of the SODA scheduler, with particular emphasis on the component, known as macroQ, which performs the job admission and resource allocation tasks. We demonstrate by experiments the natural trade-offs between job admission and resource allocation.

  13. AVQS: Attack Route-Based Vulnerability Quantification Scheme for Smart Grid

    PubMed Central

    Lim, Hyunwoo; Lee, Seokjun; Shon, Taeshik

    2014-01-01

    A smart grid is a large, consolidated electrical grid system that includes heterogeneous networks and systems. Based on the data, a smart grid system has a potential security threat in its network connectivity. To solve this problem, we develop and apply a novel scheme to measure the vulnerability in a smart grid domain. Vulnerability quantification can be the first step in security analysis because it can help prioritize the security problems. However, existing vulnerability quantification schemes are not suitable for smart grid because they do not consider network vulnerabilities. We propose a novel attack route-based vulnerability quantification scheme using a network vulnerability score and an end-to-end security score, depending on the specific smart grid network environment to calculate the vulnerability score for a particular attack route. To evaluate the proposed approach, we derive several attack scenarios from the advanced metering infrastructure domain. The experimental results of the proposed approach and the existing common vulnerability scoring system clearly show that we need to consider network connectivity for more optimized vulnerability quantification. PMID:25152923

  14. A QR code based zero-watermarking scheme for authentication of medical images in teleradiology cloud.

    PubMed

    Seenivasagam, V; Velumani, R

    2013-01-01

    Healthcare institutions adapt cloud based archiving of medical images and patient records to share them efficiently. Controlled access to these records and authentication of images must be enforced to mitigate fraudulent activities and medical errors. This paper presents a zero-watermarking scheme implemented in the composite Contourlet Transform (CT)-Singular Value Decomposition (SVD) domain for unambiguous authentication of medical images. Further, a framework is proposed for accessing patient records based on the watermarking scheme. The patient identification details and a link to patient data encoded into a Quick Response (QR) code serves as the watermark. In the proposed scheme, the medical image is not subjected to degradations due to watermarking. Patient authentication and authorized access to patient data are realized on combining a Secret Share with the Master Share constructed from invariant features of the medical image. The Hu's invariant image moments are exploited in creating the Master Share. The proposed system is evaluated with Checkmark software and is found to be robust to both geometric and non geometric attacks. PMID:23970943

  15. AVQS: attack route-based vulnerability quantification scheme for smart grid.

    PubMed

    Ko, Jongbin; Lim, Hyunwoo; Lee, Seokjun; Shon, Taeshik

    2014-01-01

    A smart grid is a large, consolidated electrical grid system that includes heterogeneous networks and systems. Based on the data, a smart grid system has a potential security threat in its network connectivity. To solve this problem, we develop and apply a novel scheme to measure the vulnerability in a smart grid domain. Vulnerability quantification can be the first step in security analysis because it can help prioritize the security problems. However, existing vulnerability quantification schemes are not suitable for smart grid because they do not consider network vulnerabilities. We propose a novel attack route-based vulnerability quantification scheme using a network vulnerability score and an end-to-end security score, depending on the specific smart grid network environment to calculate the vulnerability score for a particular attack route. To evaluate the proposed approach, we derive several attack scenarios from the advanced metering infrastructure domain. The experimental results of the proposed approach and the existing common vulnerability scoring system clearly show that we need to consider network connectivity for more optimized vulnerability quantification. PMID:25152923

  16. Compute unified device architecture (CUDA)-based parallelization of WRF Kessler cloud microphysics scheme

    NASA Astrophysics Data System (ADS)

    Mielikainen, Jarno; Huang, Bormin; Wang, Jun; Allen Huang, H.-L.; Goldberg, Mitchell D.

    2013-03-01

    In recent years, graphics processing units (GPUs) have emerged as a low-cost, low-power and a very high performance alternative to conventional central processing units (CPUs). The latest GPUs offer a speedup of two-to-three orders of magnitude over CPU for various science and engineering applications. The Weather Research and Forecasting (WRF) model is the latest-generation numerical weather prediction model. It has been designed to serve both operational forecasting and atmospheric research needs. It proves useful for a broad spectrum of applications for domain scales ranging from meters to hundreds of kilometers. WRF computes an approximate solution to the differential equations which govern the air motion of the whole atmosphere. Kessler microphysics module in WRF is a simple warm cloud scheme that includes water vapor, cloud water and rain. Microphysics processes which are modeled are rain production, fall and evaporation. The accretion and auto-conversion of cloud water processes are also included along with the production of cloud water from condensation. In this paper, we develop an efficient WRF Kessler microphysics scheme which runs on Graphics Processing Units (GPUs) using the NVIDIA Compute Unified Device Architecture (CUDA). The GPU-based implementation of Kessler microphysics scheme achieves a significant speedup of 70× over its CPU based single-threaded counterpart. When a 4 GPU system is used, we achieve an overall speedup of 132× as compared to the single thread CPU version.

  17. 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. PMID:26933630

  18. A QR Code Based Zero-Watermarking Scheme for Authentication of Medical Images in Teleradiology Cloud

    PubMed Central

    Seenivasagam, V.; Velumani, R.

    2013-01-01

    Healthcare institutions adapt cloud based archiving of medical images and patient records to share them efficiently. Controlled access to these records and authentication of images must be enforced to mitigate fraudulent activities and medical errors. This paper presents a zero-watermarking scheme implemented in the composite Contourlet Transform (CT)—Singular Value Decomposition (SVD) domain for unambiguous authentication of medical images. Further, a framework is proposed for accessing patient records based on the watermarking scheme. The patient identification details and a link to patient data encoded into a Quick Response (QR) code serves as the watermark. In the proposed scheme, the medical image is not subjected to degradations due to watermarking. Patient authentication and authorized access to patient data are realized on combining a Secret Share with the Master Share constructed from invariant features of the medical image. The Hu's invariant image moments are exploited in creating the Master Share. The proposed system is evaluated with Checkmark software and is found to be robust to both geometric and non geometric attacks. PMID:23970943

  19. 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

  20. Efficient alignment scheme for zone-plates-based transmission soft X-ray microscope

    NASA Astrophysics Data System (ADS)

    Lim, Jun; Shin, Hyun-Joon; Hong, Chung Ki

    2010-12-01

    Alignment and operation of a zone-plate (ZP)-based transmission soft X-ray microscope (TXM) is difficult and time consuming, especially when the TXM has no dedicated X-ray source. We introduce here an efficient TXM alignment scheme. The TXM employed is a simple in-situ-experiment-capable setup. It includes ultrahigh-vacuum (UHV)-compatible conflat flanges and is mountable in tandem with any soft X-ray synchrotron radiation beamlines. Obtaining zeroth- and first-order diffracted (condenser-zone-plate [CZP]-focused) beams simultaneously by means of the objective zone plate (OZP) is the most essential step in the alignment scheme. We were able to acquire, in one hour at a radiation wavelength of 2.49 nm, an image of 50 nm spatial resolution.

  1. Secure bidirectional transmission in a WDM-PON architecture employing RSOA-based remodulation scheme

    NASA Astrophysics Data System (ADS)

    Das, Anindya S.; Patra, Ardhendu S.

    2015-01-01

    A novel architecture of bidirectional wavelength division multiplexed passive optical network (WDM-PON), based on forward error correcting (FEC) scheme, has been proposed and analyzed theoretically. This configuration is made economical by employing injection locked Fabry-Perot laser diode (FPLD) for direct modulation at transmitter end and reflective semiconductor optical amplifier (RSOA) as remodulator at receiver end. Reed-Solomon (RS) codec is preferred in the design to comprehend the FEC scheme. The RS (255, 251) codec is realized by field-programmablegate- array (FPGA) with the help of VERILOG programming. Excellent transmission performances of 10 Gbps datasignal over maximum of 20 km SMF in downlink and uplink are obtained by the low bit error rate (BER) values and significant eye diagrams at BER analyzer.

  2. A controlled variation scheme for convection treatment in pressure-based algorithm

    NASA Technical Reports Server (NTRS)

    Shyy, Wei; Thakur, Siddharth; Tucker, Kevin

    1993-01-01

    Convection effect and source terms are two primary sources of difficulties in computing turbulent reacting flows typically encountered in propulsion devices. The present work intends to elucidate the individual as well as the collective roles of convection and source terms in the fluid flow equations, and to devise appropriate treatments and implementations to improve our current capability of predicting such flows. A controlled variation scheme (CVS) has been under development in the context of a pressure-based algorithm, which has the characteristics of adaptively regulating the amount of numerical diffusivity, relative to central difference scheme, according to the variation in local flow field. Both the basic concepts and a pragmatic assessment will be presented to highlight the status of this work.

  3. Informatics-Based Energy Fitting Scheme for Correlation Energy at Complete Basis Set Limit.

    PubMed

    Seino, Junji; Nakai, Hiromi

    2016-09-30

    Energy fitting schemes based on informatics techniques using hierarchical basis sets with small cardinal numbers were numerically investigated to estimate correlation energies at the complete basis set limits. Numerical validations confirmed that the conventional two-point extrapolation models can be unified into a simple formula with optimal parameters obtained by the same test sets. The extrapolation model was extended to two-point fitting models by a relaxation of the relationship between the extrapolation coefficients or a change of the fitting formula. Furthermore, n-scheme fitting models were developed by the combinations of results calculated at several theory levels and basis sets to compensate for the deficiencies in the fitting model at one level of theory. Systematic assessments on the Gaussian-3X and Gaussian-2 sets revealed that the fitting models drastically reduced errors with equal or smaller computational effort. © 2016 Wiley Periodicals, Inc. PMID:27454327

  4. A Review on Successive Interference Cancellation Scheme Based on Optical CDMA Network

    NASA Astrophysics Data System (ADS)

    Alsowaidi, N.; Eltaif, T.; Mokhtar, M. R.

    2014-12-01

    Due to various desirable features of optical code division multiple access (OCDMA), it is believed this technique once developed and commercially available will be an integral part of optical access networks. Optical CDMA system suffers from a problem called multiple access interference (MAI) which limits the number of active users, it occurs when number of active users share the same carriers. The aim of this paper is to review successive interference cancellation (SIC) scheme based on optical CDMA system. The paper also reviews the system performance in presence of shot noise, thermal noise, and phase-induced intensity noise (PIIN). A comprehensive review on the mathematical model of SIC scheme using direct detection (DS) and spectral amplitude coding (SAC) were presented in this article.

  5. ‘Baseline-offset’ scheme for a methane remote sensor based on wavelength modulation spectroscopy

    NASA Astrophysics Data System (ADS)

    Ding, Wuwen; Sun, Liqun; Yi, Luying; Zhang, Enyao

    2016-08-01

    A new scheme for methane remote sensing is presented. Unlike a standard published remote sensor based on wavelength modulation spectroscopy (WMS), a reference cell is inserted into the measuring optical path. This scheme inherits the merits of WMS and can achieve high signal-to-noise ratio especially in a low concentration environment. Experimental results show that the presented remote sensor can detect ambient methane with a detection limit of 5 ppm m (parts per million · meter) at a distance of 10 m and 16 ppm m for 20 m. A methane leak test shows the sensor can detect a methane leak of 15 ml min‑1 within a range up to 37 m.

  6. An adaptive critic-based scheme for consensus control of nonlinear multi-agent systems

    NASA Astrophysics Data System (ADS)

    Heydari, Ali; Balakrishnan, S. N.

    2014-12-01

    The problem of decentralised consensus control of a network of heterogeneous nonlinear systems is formulated as an optimal tracking problem and a solution is proposed using an approximate dynamic programming based neurocontroller. The neurocontroller training comprises an initial offline training phase and an online re-optimisation phase to account for the fact that the reference signal subject to tracking is not fully known and available ahead of time, i.e., during the offline training phase. As long as the dynamics of the agents are controllable, and the communication graph has a directed spanning tree, this scheme guarantees the synchronisation/consensus even under switching communication topology and directed communication graph. Finally, an aerospace application is selected for the evaluation of the performance of the method. Simulation results demonstrate the potential of the scheme.

  7. High capacity data hiding scheme based on (7, 4) Hamming code.

    PubMed

    Cao, Zekun; Yin, Zhaoxia; Hu, Honghe; Gao, Xiangping; Wang, Liangmin

    2016-01-01

    Aiming to embed large amount of data while minimize the sum of costs of all changed pixels, a novel high capacity data hiding scheme based on (7, 4) Hamming code is realized by a family of algorithms. Firstly, n (n = 1, 2, 3) cover pixels are assigned to one set according to the payload. Then, 128 binary strings of length seven are divided into eight sets according to the syndrome of every binary string. Binary strings that share the same syndrome are classified into one set. Finally, a binary string in a certain set determined by the data to be embedded is chosen to modify some of the least significant bits of the n cover pixels. The experimental results demonstrate that the image quality of the proposed method with high embedding payload is superior to those of the related schemes. PMID:27026872

  8. An authenticated image encryption scheme based on chaotic maps and memory cellular automata

    NASA Astrophysics Data System (ADS)

    Bakhshandeh, Atieh; Eslami, Ziba

    2013-06-01

    This paper introduces a new image encryption scheme based on chaotic maps, cellular automata and permutation-diffusion architecture. In the permutation phase, a piecewise linear chaotic map is utilized to confuse the plain-image and in the diffusion phase, we employ the Logistic map as well as a reversible memory cellular automata to obtain an efficient and secure cryptosystem. The proposed method admits advantages such as highly secure diffusion mechanism, computational efficiency and ease of implementation. A novel property of the proposed scheme is its authentication ability which can detect whether the image is tampered during the transmission or not. This is particularly important in applications where image data or part of it contains highly sensitive information. Results of various analyses manifest high security of this new method and its capability for practical image encryption.

  9. Skin formation in drying a film of soft matter solutions: Application of solute based Lagrangian scheme

    NASA Astrophysics Data System (ADS)

    Ling, Luo; Fanlong, Meng; Junying, Zhang; Masao, Doi

    2016-07-01

    When a film of soft matter solutions is being dried, a skin layer often forms at its surface, which is a gel-like elastic phase made of concentrated soft matter solutions. We study the dynamics of this process by using the solute based Lagrangian scheme which was proposed by us recently. In this scheme, the process of the gelation (i.e., the change from sol to gel) can be naturally incorporated in the diffusion equation. Effects of the elasticity of the skin phase, the evaporation rate of the solvents, and the initial concentration of the solutions are discussed. Moreover, the condition for the skin formation is provided. Project supported by the National Natural Science of China (Grant Nos. 21434001, 51561145002, and 11421110001).

  10. Power consumption analysis of priority-based service differentiation scheme for LR-WPANs

    NASA Astrophysics Data System (ADS)

    Kim, Meejoung; Hwang, Eenjun

    2016-06-01

    In this paper, we investigate the effect of service differentiation on the power consumption in contention period of IEEE 802.15.4 sensor networks. Power consumption is analysed for two different service differentiation schemes under non-saturation condition. The two service differentiation schemes are the differentiation by the backoff exponent (BED) and differentiation by the contention window (CWD), which provide multilevel differentiated services in beacon-enabled mode with slotted carrier sense multiple access/collision avoidance (CSMA/CA) algorithm. The analysis is based on the stationary probabilities of a discrete-time Markov chain, which is a model of CSMA/CA describing the state of a head packet of a device. Numerical results show that CWD uses the power more efficiently and performs better in terms of throughput, while BED more differentiates the service.

  11. Object-oriented image coding scheme based on DWT and Markov random field

    NASA Astrophysics Data System (ADS)

    Zheng, Lei; Wu, Hsien-Hsun S.; Liu, Jyh-Charn S.; Chan, Andrew K.

    1998-12-01

    In this paper, we introduce an object-oriented image coding algorithm to differentiate regions of interest (ROI) in visual communications. Our scheme is motivated by the fact that in visual communications, image contents (objects) are not equally important. For a given network bandwidth budget, one should give the highest transmission priority to the most interesting object, and serve the remaining ones at lower priorities. We propose a DWT based Multiresolution Markov Random Field technique to segment image objects according to their textures. We show that this technique can effectively distinguish visual objects and assign them different priorities. This scheme can be integrated with our ROI compression coder, the Generalized Self-Similarity Tress codex, for networking applications.

  12. Are outcome-adaptive allocation trials ethical?

    PubMed

    Hey, Spencer Phillips; Kimmelman, Jonathan

    2015-04-01

    Randomization is firmly established as a cornerstone of clinical trial methodology. Yet, the ethics of randomization continues to generate controversy. The default, and most efficient, allocation scheme randomizes patients equally (1:1) across all arms of study. However, many randomized trials are using outcome-adaptive allocation schemes, which dynamically adjust the allocation ratio in favor of the better performing treatment arm. Advocates of outcome-adaptive allocation contend that it better accommodates clinical equipoise and promotes informed consent, since such trials limit patient-subject exposure to sub-optimal care. In this essay, we argue that this purported ethical advantage of outcome-adaptive allocation does not stand up to careful scrutiny in the setting of two-armed studies and/or early-phase research. PMID:25649106

  13. A novel fully automatic scheme for fiducial marker-based alignment in electron tomography.

    PubMed

    Han, Renmin; Wang, Liansan; Liu, Zhiyong; Sun, Fei; Zhang, Fa

    2015-12-01

    Although the topic of fiducial marker-based alignment in electron tomography (ET) has been widely discussed for decades, alignment without human intervention remains a difficult problem. Specifically, the emergence of subtomogram averaging has increased the demand for batch processing during tomographic reconstruction; fully automatic fiducial marker-based alignment is the main technique in this process. However, the lack of an accurate method for detecting and tracking fiducial markers precludes fully automatic alignment. In this paper, we present a novel, fully automatic alignment scheme for ET. Our scheme has two main contributions: First, we present a series of algorithms to ensure a high recognition rate and precise localization during the detection of fiducial markers. Our proposed solution reduces fiducial marker detection to a sampling and classification problem and further introduces an algorithm to solve the parameter dependence of marker diameter and marker number. Second, we propose a novel algorithm to solve the tracking of fiducial markers by reducing the tracking problem to an incomplete point set registration problem. Because a global optimization of a point set registration occurs, the result of our tracking is independent of the initial image position in the tilt series, allowing for the robust tracking of fiducial markers without pre-alignment. The experimental results indicate that our method can achieve an accurate tracking, almost identical to the current best one in IMOD with half automatic scheme. Furthermore, our scheme is fully automatic, depends on fewer parameters (only requires a gross value of the marker diameter) and does not require any manual interaction, providing the possibility of automatic batch processing of electron tomographic reconstruction. PMID:26433028

  14. Complex absorbing potential based Lorentzian fitting scheme and time dependent quantum transport

    SciTech Connect

    Xie, Hang Kwok, Yanho; Chen, GuanHua; Jiang, Feng; Zheng, Xiao

    2014-10-28

    Based on the complex absorbing potential (CAP) method, a Lorentzian expansion scheme is developed to express the self-energy. The CAP-based Lorentzian expansion of self-energy is employed to solve efficiently the Liouville-von Neumann equation of one-electron density matrix. The resulting method is applicable for both tight-binding and first-principles models and is used to simulate the transient currents through graphene nanoribbons and a benzene molecule sandwiched between two carbon-atom chains.

  15. Water consumption and allocation strategies along the river oases of Tarim River based on large-scale hydrological modelling

    NASA Astrophysics Data System (ADS)

    Yu, Yang; Disse, Markus; Yu, Ruide

    2016-04-01

    With the mainstream of 1,321km and located in an arid area in northwest China, the Tarim River is China's longest inland river. The Tarim basin on the northern edge of the Taklamakan desert is an extremely arid region. In this region, agricultural water consumption and allocation management are crucial to address the conflicts among irrigation water users from upstream to downstream. Since 2011, the German Ministry of Science and Education BMBF established the Sino-German SuMaRiO project, for the sustainable management of river oases along the Tarim River. The project aims to contribute to a sustainable land management which explicitly takes into account ecosystem functions and ecosystem services. SuMaRiO will identify realizable management strategies, considering social, economic and ecological criteria. This will have positive effects for nearly 10 million inhabitants of different ethnic groups. The modelling of water consumption and allocation strategies is a core block in the SuMaRiO cluster. A large-scale hydrological model (MIKE HYDRO Basin) was established for the purpose of sustainable agricultural water management in the main stem Tarim River. MIKE HYDRO Basin is an integrated, multipurpose, map-based decision support tool for river basin analysis, planning and management. It provides detailed simulation results concerning water resources and land use in the catchment areas of the river. Calibration data and future predictions based on large amount of data was acquired. The results of model calibration indicated a close correlation between simulated and observed values. Scenarios with the change on irrigation strategies and land use distributions were investigated. Irrigation scenarios revealed that the available irrigation water has significant and varying effects on the yields of different crops. Irrigation water saving could reach up to 40% in the water-saving irrigation scenario. Land use scenarios illustrated that an increase of farmland area in the

  16. Cryptanalysis of a modified encryption scheme based on bent Boolean function and feedback with carry shift register

    NASA Astrophysics Data System (ADS)

    Stoyanov, B. P.; Kordov, K. M.

    2013-10-01

    We propose a modified encryption scheme based on 256 bit bent Boolean function and Feedback with Carry Shift Register. We estimated the output bits properties by the NIST, DIEHARD and ENT test packages. The results of the cryptanalysis show that the new cryptographic scheme provides an exclusive level of data security.

  17. A theory-based evaluation of a community-based funding scheme in a disadvantaged suburban city area.

    PubMed

    Hickey, Gráinne; McGilloway, Sinead; O'Brien, Morgan; Leckey, Yvonne; Devlin, Maurice

    2015-10-01

    Community-driven development (CDD) initiatives frequently involve funding schemes which are aimed at channelling financial investment into local need and fostering community participation and engagement. This exploratory study examined, through a program theory approach, the design and implementation of a small-scale, community-based fund in Ireland. Observations, documentary analysis, interviews and group discussions with 19 participants were utilized to develop a detailed understanding of the program mechanisms, activities and processes, as well as the experiences of key stakeholders engaged with the funding scheme and its implementation. The findings showed that there were positive perceptions of the scheme and its function within the community. Overall, the availability of funding was perceived by key stakeholders as being beneficial. However, there were concerns over the accessibility of the scheme for more marginalized members of the community, as well as dissatisfaction with the openness and transparency surrounding funding eligibility. Lessons for the implementation of small-scale CDD funds are elaborated and the utility of program theory approaches for evaluators and planners working with programs that fund community-based initiatives is outlined. PMID:25933408

  18. Constant-quality constrained-rate allocation for FGS video coded bitstreams

    NASA Astrophysics Data System (ADS)

    Zhang, Xi Min; Vetro, Anthony; Shi, Yun-Qing; Sun, Huifang

    2002-01-01

    This paper proposes an optimal rate allocation scheme for Fine-Granular Scalability (FGS) coded bitstreams that can achieve constant quality reconstruction of frames under a dynamic rate budget constraint. In doing so, we also aim to minimize the overall distortion at the same time. To achieve this, we propose a novel R-D labeling scheme to characterize the R-D relationship of the source coding process. Specifically, sets of R-D points are extracted during the encoding process and linear interpolation is used to estimate the actual R-D curve of the enhancement layer signal. The extracted R-D information is then used by an enhancement layer transcoder to determine the bits that should be allocated per frame. A sliding window based rate allocation method is proposed to realize constant quality among frames. This scheme is first considered for a single FGS coded source, then extended to operate on multiple sources. With the proposed scheme, the rate allocation can be performed in a single pass, hence the complexity is quite low. Experimental results confirm the effectiveness of the proposed scheme under static and dynamic bandwidth conditions.

  19. A New Image Encryption Scheme Based on Dynamic S-Boxes and Chaotic Maps

    NASA Astrophysics Data System (ADS)

    Rehman, Atique Ur; Khan, Jan Sher; Ahmad, Jawad; Hwang, Soeng Oun

    2016-03-01

    Substitution box is a unique and nonlinear core component of block ciphers. A better designing technique of substitution box can boost up the quality of ciphertexts. In this paper, a new encryption method based on dynamic substitution boxes is proposed via using two chaotic maps. To break the correlation in an original image, pixels values of the original plaintext image are permuted row- and column-wise through random sequences. The aforementioned random sequences are generated by 2-D Burgers chaotic map. For the generation of dynamic substitution boxes, Logistic chaotic map is employed. In the process of diffusion, the permuted image is divided into blocks and each block is substituted via different dynamic substitution boxes. In contrast to conventional encryption schemes, the proposed scheme does not undergo the fixed block cipher and hence the security level can be enhanced. Extensive security analysis including histogram test is applied on the proposed image encryption technique. All experimental results reveal that the proposed scheme has a high level of security and robustness for transmission of digital images on insecure communication channels.

  20. A Trust-Based Adaptive Probability Marking and Storage Traceback Scheme for WSNs.

    PubMed

    Liu, Anfeng; Liu, Xiao; Long, Jun

    2016-01-01

    Security is a pivotal issue for wireless sensor networks (WSNs), which are emerging as a promising platform that enables a wide range of military, scientific, industrial and commercial applications. Traceback, a key cyber-forensics technology, can play an important role in tracing and locating a malicious source to guarantee cybersecurity. In this work a trust-based adaptive probability marking and storage (TAPMS) traceback scheme is proposed to enhance security for WSNs. In a TAPMS scheme, the marking probability is adaptively adjusted according to the security requirements of the network and can substantially reduce the number of marking tuples and improve network lifetime. More importantly, a high trust node is selected to store marking tuples, which can avoid the problem of marking information being lost. Experimental results show that the total number of marking tuples can be reduced in a TAPMS scheme, thus improving network lifetime. At the same time, since the marking tuples are stored in high trust nodes, storage reliability can be guaranteed, and the traceback time can be reduced by more than 80%. PMID:27043566

  1. A Trust-Based Adaptive Probability Marking and Storage Traceback Scheme for WSNs

    PubMed Central

    Liu, Anfeng; Liu, Xiao; Long, Jun

    2016-01-01

    Security is a pivotal issue for wireless sensor networks (WSNs), which are emerging as a promising platform that enables a wide range of military, scientific, industrial and commercial applications. Traceback, a key cyber-forensics technology, can play an important role in tracing and locating a malicious source to guarantee cybersecurity. In this work a trust-based adaptive probability marking and storage (TAPMS) traceback scheme is proposed to enhance security for WSNs. In a TAPMS scheme, the marking probability is adaptively adjusted according to the security requirements of the network and can substantially reduce the number of marking tuples and improve network lifetime. More importantly, a high trust node is selected to store marking tuples, which can avoid the problem of marking information being lost. Experimental results show that the total number of marking tuples can be reduced in a TAPMS scheme, thus improving network lifetime. At the same time, since the marking tuples are stored in high trust nodes, storage reliability can be guaranteed, and the traceback time can be reduced by more than 80%. PMID:27043566

  2. Vector quantization based on a psychovisual lattice for a visual subband coding scheme

    NASA Astrophysics Data System (ADS)

    Senane, Hakim; Saadane, Abdelhakim; Barba, Dominique

    1997-01-01

    A vector quantization based on a psychovisual lattice is used in a visual components image coding scheme to achieve a high compression ratio with an excellent visual quality. The vectors construction methodology preserves the main properties of the human visual system concerning the perception of quantization impairments and takes into account the masking effect due to interaction between subbands with the same radial frequency but with different orientations. The vectors components are the local band limited contrasts Cij defined as the ratio between the luminance Lij at point, which belongs to the radial subband i and angular sector j, and the average luminance at this location corresponding to the radial frequencies up to subband i-1. Hence the vectors dimension is depending on the orientation selectivity of the chosen decomposition. The low pass subband, which is nondirectional is scalar quantized. The performances of the coding scheme have been evaluated on a set of images in terms of peak SNR, true bit rates and visual quality. For this, no impairments are visible at a distance of 4 times the height of a high quality TV monitor. The SNR are about 6 to 8 dB under the ones of classical subband image coding schemes when producing the same visual quality. Due to the use of the local band limited contrast, the particularity of this approach relies in the structure of the reconstruction image error which is found to be highly correlated to the structure of the original image.

  3. Public automated web-based evaluation service for watermarking schemes: StirMark benchmark

    NASA Astrophysics Data System (ADS)

    Petitcolas, Fabien A. P.; Steinebach, Martin; Raynal, Frederic; Dittmann, Jana; Fontaine, Caroline; Fates, Nazim

    2001-08-01

    One of the main problems, which darkens the future of digital watermarking technologies, is the lack of detailed evaluation of existing marking schemes. This lack of benchmarking of current algorithms is blatant and confuses rights holders as well as software and hardware manufacturers and prevents them from using the solution appropriate to their needs. Indeed basing long-lived protection schemes on badly tested watermarking technology does not make sense. In this paper we will present the architecture of a public automated evaluation service we have developed for still images, sound and video. We will detail and justify our choice of evaluation profiles, that is the series of tests applied to different types of wa-termarking schemes. These evaluation profiles allow us to measure the reliability of a marking scheme to different levels from low to very high. Beside the known StirMark transformations, we will also detail new tests that will be included in this platform. One of them is intended to measure the real size of the key space. Indeed, if one is not careful, two different watermarking keys may produce interfering watermarks and as a consequence the actual space of keys is much smaller than it appears. Another set of tests is related to audio data and addresses the usual equalisation and normalisation but also time stretching, pitch shifting. Finally we propose a set of tests for fingerprinting applications. This includes: averaging of copies with different fingerprint, random ex-change of part between different copies and comparison between copies with selection of most/less frequently used position differences.

  4. A broadcast-based key agreement scheme using set reconciliation for wireless body area networks.

    PubMed

    Ali, Aftab; Khan, Farrukh Aslam

    2014-05-01

    Information and communication technologies have thrived over the last few years. Healthcare systems have also benefited from this progression. A wireless body area network (WBAN) consists of small, low-power sensors used to monitor human physiological values remotely, which enables physicians to remotely monitor the health of patients. Communication security in WBANs is essential because it involves human physiological data. Key agreement and authentication are the primary issues in the security of WBANs. To agree upon a common key, the nodes exchange information with each other using wireless communication. This information exchange process must be secure enough or the information exchange should be minimized to a certain level so that if information leak occurs, it does not affect the overall system. Most of the existing solutions for this problem exchange too much information for the sake of key agreement; getting this information is sufficient for an attacker to reproduce the key. Set reconciliation is a technique used to reconcile two similar sets held by two different hosts with minimal communication complexity. This paper presents a broadcast-based key agreement scheme using set reconciliation for secure communication in WBANs. The proposed scheme allows the neighboring nodes to agree upon a common key with the personal server (PS), generated from the electrocardiogram (EKG) feature set of the host body. Minimal information is exchanged in a broadcast manner, and even if every node is missing a different subset, by reconciling these feature sets, the whole network will still agree upon a single common key. Because of the limited information exchange, if an attacker gets the information in any way, he/she will not be able to reproduce the key. The proposed scheme mitigates replay, selective forwarding, and denial of service attacks using a challenge-response authentication mechanism. The simulation results show that the proposed scheme has a great deal of

  5. 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. PMID:26743628

  6. Popularity-aware rate allocation in multiview video

    NASA Astrophysics Data System (ADS)

    Fiandrotti, Attilio; Chakareski, Jacob; Frossard, Pascal

    2010-07-01

    We propose a framework for popularity-driven rate allocation in H.264/MVC-based multi-view video communications when the overall rate and the rate necessary for decoding each view are constrained in the delivery architecture. We formulate a rate allocation optimization problem that takes into account the popularity of each view among the client population and the rate-distortion characteristics of the multi-view sequence so that the performance of the system is maximized in terms of popularity-weighted average quality. We consider the cases where the global bit budget or the decoding rate of each view is constrained. We devise a simple ratevideo- quality model that accounts for the characteristics of interview prediction schemes typical of multi-view video. The video quality model is used for solving the rate allocation problem with the help of an interior point optimization method. We then show through experiments that the proposed rate allocation scheme clearly outperforms baseline solutions in terms of popularity-weighted video quality. In particular, we demonstrate that the joint knowledge of the rate-distortion characteristics of the video content, its coding dependencies, and the popularity factor of each view is key in achieving good coding performance in multi-view video systems.

  7. Lessons from community-based payment for ecosystem service schemes: from forests to rangelands.

    PubMed

    Dougill, Andrew J; Stringer, Lindsay C; Leventon, Julia; Riddell, Mike; Rueff, Henri; Spracklen, Dominick V; Butt, Edward

    2012-11-19

    Climate finance investments and international policy are driving new community-based projects incorporating payments for ecosystem services (PES) to simultaneously store carbon and generate livelihood benefits. Most community-based PES (CB-PES) research focuses on forest areas. Rangelands, which store globally significant quantities of carbon and support many of the world's poor, have seen little CB-PES research attention, despite benefitting from several decades of community-based natural resource management (CBNRM) projects. Lessons from CBNRM suggest institutional considerations are vital in underpinning the design and implementation of successful community projects. This study uses documentary analysis to explore the institutional characteristics of three African community-based forest projects that seek to deliver carbon-storage and poverty-reduction benefits. Strong existing local institutions, clear land tenure, community control over land management decision-making and up-front, flexible payment schemes are found to be vital. Additionally, we undertake a global review of rangeland CBNRM literature and identify that alongside the lessons learned from forest projects, rangeland CB-PES project design requires specific consideration of project boundaries, benefit distribution, capacity building for community monitoring of carbon storage together with awareness-raising using decision-support tools to display the benefits of carbon-friendly land management. We highlight that institutional analyses must be undertaken alongside improved scientific studies of the carbon cycle to enable links to payment schemes, and for them to contribute to poverty alleviation in rangelands. PMID:23045714

  8. A genetic algorithm based multi-objective shape optimization scheme for cementless femoral implant.

    PubMed

    Chanda, Souptick; Gupta, Sanjay; Kumar Pratihar, Dilip

    2015-03-01

    The shape and geometry of femoral implant influence implant-induced periprosthetic bone resorption and implant-bone interface stresses, which are potential causes of aseptic loosening in cementless total hip arthroplasty (THA). Development of a shape optimization scheme is necessary to achieve a trade-off between these two conflicting objectives. The objective of this study was to develop a novel multi-objective custom-based shape optimization scheme for cementless femoral implant by integrating finite element (FE) analysis and a multi-objective genetic algorithm (GA). The FE model of a proximal femur was based on a subject-specific CT-scan dataset. Eighteen parameters describing the nature of four key sections of the implant were identified as design variables. Two objective functions, one based on implant-bone interface failure criterion, and the other based on resorbed proximal bone mass fraction (BMF), were formulated. The results predicted by the two objective functions were found to be contradictory; a reduction in the proximal bone resorption was accompanied by a greater chance of interface failure. The resorbed proximal BMF was found to be between 23% and 27% for the trade-off geometries as compared to ∼39% for a generic implant. Moreover, the overall chances of interface failure have been minimized for the optimal designs, compared to the generic implant. The adaptive bone remodeling was also found to be minimal for the optimally designed implants and, further with remodeling, the chances of interface debonding increased only marginally. PMID:25392855

  9. Lessons from community-based payment for ecosystem service schemes: from forests to rangelands

    PubMed Central

    Dougill, Andrew J.; Stringer, Lindsay C.; Leventon, Julia; Riddell, Mike; Rueff, Henri; Spracklen, Dominick V.; Butt, Edward

    2012-01-01

    Climate finance investments and international policy are driving new community-based projects incorporating payments for ecosystem services (PES) to simultaneously store carbon and generate livelihood benefits. Most community-based PES (CB-PES) research focuses on forest areas. Rangelands, which store globally significant quantities of carbon and support many of the world's poor, have seen little CB-PES research attention, despite benefitting from several decades of community-based natural resource management (CBNRM) projects. Lessons from CBNRM suggest institutional considerations are vital in underpinning the design and implementation of successful community projects. This study uses documentary analysis to explore the institutional characteristics of three African community-based forest projects that seek to deliver carbon-storage and poverty-reduction benefits. Strong existing local institutions, clear land tenure, community control over land management decision-making and up-front, flexible payment schemes are found to be vital. Additionally, we undertake a global review of rangeland CBNRM literature and identify that alongside the lessons learned from forest projects, rangeland CB-PES project design requires specific consideration of project boundaries, benefit distribution, capacity building for community monitoring of carbon storage together with awareness-raising using decision-support tools to display the benefits of carbon-friendly land management. We highlight that institutional analyses must be undertaken alongside improved scientific studies of the carbon cycle to enable links to payment schemes, and for them to contribute to poverty alleviation in rangelands. PMID:23045714

  10. An Anonymous User Authentication and Key Agreement Scheme Based on a Symmetric Cryptosystem in Wireless Sensor Networks.

    PubMed

    Jung, Jaewook; Kim, Jiye; Choi, Younsung; Won, Dongho

    2016-01-01

    In wireless sensor networks (WSNs), a registered user can login to the network and use a user authentication protocol to access data collected from the sensor nodes. Since WSNs are typically deployed in unattended environments and sensor nodes have limited resources, many researchers have made considerable efforts to design a secure and efficient user authentication process. Recently, Chen et al. proposed a secure user authentication scheme using symmetric key techniques for WSNs. They claim that their scheme assures high efficiency and security against different types of attacks. After careful analysis, however, we find that Chen et al.'s scheme is still vulnerable to smart card loss attack and is susceptible to denial of service attack, since it is invalid for verification to simply compare an entered ID and a stored ID in smart card. In addition, we also observe that their scheme cannot preserve user anonymity. Furthermore, their scheme cannot quickly detect an incorrect password during login phase, and this flaw wastes both communication and computational overheads. In this paper, we describe how these attacks work, and propose an enhanced anonymous user authentication and key agreement scheme based on a symmetric cryptosystem in WSNs to address all of the aforementioned vulnerabilities in Chen et al.'s scheme. Our analysis shows that the proposed scheme improves the level of security, and is also more efficient relative to other related schemes. PMID:27537890

  11. Visual privacy by context: proposal and evaluation of a level-based visualisation scheme.

    PubMed

    Padilla-López, José Ramón; Chaaraoui, Alexandros Andre; Gu, Feng; Flórez-Revuelta, Francisco

    2015-01-01

    Privacy in image and video data has become an important subject since cameras are being installed in an increasing number of public and private spaces. Specifically, in assisted living, intelligent monitoring based on computer vision can allow one to provide risk detection and support services that increase people's autonomy at home. In the present work, a level-based visualisation scheme is proposed to provide visual privacy when human intervention is necessary, such as at telerehabilitation and safety assessment applications. Visualisation levels are dynamically selected based on the previously modelled context. In this way, different levels of protection can be provided, maintaining the necessary intelligibility required for the applications. Furthermore, a case study of a living room, where a top-view camera is installed, is presented. Finally, the performed survey-based evaluation indicates the degree of protection provided by the different visualisation models, as well as the personal privacy preferences and valuations of the users. PMID:26053746

  12. Visual Privacy by Context: Proposal and Evaluation of a Level-Based Visualisation Scheme

    PubMed Central

    Padilla-López, José Ramón; Chaaraoui, Alexandros Andre; Gu, Feng; Flórez-Revuelta, Francisco

    2015-01-01

    Privacy in image and video data has become an important subject since cameras are being installed in an increasing number of public and private spaces. Specifically, in assisted living, intelligent monitoring based on computer vision can allow one to provide risk detection and support services that increase people's autonomy at home. In the present work, a level-based visualisation scheme is proposed to provide visual privacy when human intervention is necessary, such as at telerehabilitation and safety assessment applications. Visualisation levels are dynamically selected based on the previously modelled context. In this way, different levels of protection can be provided, maintaining the necessary intelligibility required for the applications. Furthermore, a case study of a living room, where a top-view camera is installed, is presented. Finally, the performed survey-based evaluation indicates the degree of protection provided by the different visualisation models, as well as the personal privacy preferences and valuations of the users. PMID:26053746

  13. Statistical analysis of blocking probability and fragmentation based on Markov modeling of elastic spectrum allocation on fiber link

    NASA Astrophysics Data System (ADS)

    Rosa, A. N. F.; Wiatr, P.; Cavdar, C.; Carvalho, S. V.; Costa, J. C. W. A.; Wosinska, L.

    2015-11-01

    In Elastic Optical Network (EON), spectrum fragmentation refers to the existence of non-aligned, small-sized blocks of free subcarrier slots in the optical spectrum. Several metrics have been proposed in order to quantify a level of spectrum fragmentation. Approximation methods might be used for estimating average blocking probability and some fragmentation measures, but are so far unable to accurately evaluate the influence of different sizes of connection requests and do not allow in-depth investigation of blocking events and their relation to fragmentation. The analytical study of the effect of fragmentation on requests' blocking probability is still under-explored. In this work, we introduce new definitions for blocking that differentiate between the reasons for the blocking events. We developed a framework based on Markov modeling to calculate steady-state probabilities for the different blocking events and to analyze fragmentation related problems in elastic optical links under dynamic traffic conditions. This framework can also be used for evaluation of different definitions of fragmentation in terms of their relation to the blocking probability. We investigate how different allocation request sizes contribute to fragmentation and blocking probability. Moreover, we show to which extend blocking events, due to insufficient amount of available resources, become inevitable and, compared to the amount of blocking events due to fragmented spectrum, we draw conclusions on the possible gains one can achieve by system defragmentation. We also show how efficient spectrum allocation policies really are in reducing the part of fragmentation that in particular leads to actual blocking events. Simulation experiments are carried out showing good match with our analytical results for blocking probability in a small scale scenario. Simulated blocking probabilities for the different blocking events are provided for a larger scale elastic optical link.

  14. 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

  15. 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

    2014-01-01

    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

  16. Robust biometrics based authentication and key agreement scheme for multi-server environments using smart cards.

    PubMed

    Lu, Yanrong; Li, Lixiang; Yang, Xing; Yang, Yixian

    2015-01-01

    Biometrics authenticated schemes using smart cards have attracted much attention in multi-server environments. Several schemes of this type where proposed in the past. However, many of them were found to have some design flaws. This paper concentrates on the security weaknesses of the three-factor authentication scheme by Mishra et al. After careful analysis, we find their scheme does not really resist replay attack while failing to provide an efficient password change phase. We further propose an improvement of Mishra et al.'s scheme with the purpose of preventing the security threats of their scheme. We demonstrate the proposed scheme is given to strong authentication against several attacks including attacks shown in the original scheme. In addition, we compare the performance and functionality with other multi-server authenticated key schemes. PMID:25978373

  17. Robust Biometrics Based Authentication and Key Agreement Scheme for Multi-Server Environments Using Smart Cards

    PubMed Central

    Lu, Yanrong; Li, Lixiang; Yang, Xing; Yang, Yixian

    2015-01-01

    Biometrics authenticated schemes using smart cards have attracted much attention in multi-server environments. Several schemes of this type where proposed in the past. However, many of them were found to have some design flaws. This paper concentrates on the security weaknesses of the three-factor authentication scheme by Mishra et al. After careful analysis, we find their scheme does not really resist replay attack while failing to provide an efficient password change phase. We further propose an improvement of Mishra et al.’s scheme with the purpose of preventing the security threats of their scheme. We demonstrate the proposed scheme is given to strong authentication against several attacks including attacks shown in the original scheme. In addition, we compare the performance and functionality with other multi-server authenticated key schemes. PMID:25978373

  18. Robust wavelet-based video watermarking scheme for copyright protection using the human visual system

    NASA Astrophysics Data System (ADS)

    Preda, Radu O.; Vizireanu, Dragos Nicolae

    2011-01-01

    The development of the information technology and computer networks facilitates easy duplication, manipulation, and distribution of digital data. Digital watermarking is one of the proposed solutions for effectively safeguarding the rightful ownership of digital images and video. We propose a public digital watermarking technique for video copyright protection in the discrete wavelet transform domain. The scheme uses binary images as watermarks. These are embedded in the detail wavelet coefficients of the middle wavelet subbands. The method is a combination of spread spectrum and quantization-based watermarking. Every bit of the watermark is spread over a number of wavelet coefficients with the use of a secret key by means of quantization. The selected wavelet detail coefficients from different subbands are quantized using an optimal quantization model, based on the characteristics of the human visual system (HVS). Our HVS-based scheme is compared to a non-HVS approach. The resilience of the watermarking algorithm is tested against a series of different spatial, temporal, and compression attacks. To improve the robustness of the algorithm, we use error correction codes and embed the watermark with spatial and temporal redundancy. The proposed method achieves a good perceptual quality and high resistance to a large spectrum of attacks.

  19. Agent-based power sharing scheme for active hybrid power sources

    NASA Astrophysics Data System (ADS)

    Jiang, Zhenhua

    The active hybridization technique provides an effective approach to combining the best properties of a heterogeneous set of power sources to achieve higher energy density, power density and fuel efficiency. Active hybrid power sources can be used to power hybrid electric vehicles with selected combinations of internal combustion engines, fuel cells, batteries, and/or supercapacitors. They can be deployed in all-electric ships to build a distributed electric power system. They can also be used in a bulk power system to construct an autonomous distributed energy system. An important aspect in designing an active hybrid power source is to find a suitable control strategy that can manage the active power sharing and take advantage of the inherent scalability and robustness benefits of the hybrid system. This paper presents an agent-based power sharing scheme for active hybrid power sources. To demonstrate the effectiveness of the proposed agent-based power sharing scheme, simulation studies are performed for a hybrid power source that can be used in a solar car as the main propulsion power module. Simulation results clearly indicate that the agent-based control framework is effective to coordinate the various energy sources and manage the power/voltage profiles.

  20. An improved scheme based on log-likelihood-ratio for lattice reduction-aided MIMO detection

    NASA Astrophysics Data System (ADS)

    Song, Yunchao; Liu, Chen; Lu, Feng

    2016-01-01

    Lattice reduction (LR)-aided detectors have been shown great potentials in wireless communications for their low complexity and low bit-error-rate (BER) performance. The LR algorithms use the unimodular transformation to improve the orthogonality of the channel matrix. However, the LR algorithms only utilize the channel state information (CSI) and do not take account for the received signal, which is also important information in enhancing the performance of the detectors. In this paper, we make a readjustment of the received signal in the LR domain and propose a new scheme which is based on the log-likelihood-ratio (LLR) criterion to improve the LR-aided detectors. The motivation of using the LLR criterion is that it utilizes both the received signal and the CSI, so that it can provide exact pairwise error probabilities (PEPs) of the symbols. Then, in the proposed scheme, we design the LLR-based transformation algorithm (TA) which uses the unimodular transformation to minimize the PEPs of the symbols by the LLR criterion. Note that the PEPs of the symbols affect the error propagation in the vertical Bell Laboratories Layered Space-Time (VBLAST) detector, and decreasing the PEPs can reduce the error propagation in the VBLAST detectors; thus, our LLR-based TA-aided VBLAST detectors will exhibit better BER performance than the previous LR-aided VBLAST detectors. Both the BER performance and the computational complexity are demonstrated through the simulation results.

  1. Design of an image encryption scheme based on a multiple chaotic map

    NASA Astrophysics Data System (ADS)

    Tong, Xiao-Jun

    2013-07-01

    In order to solve the problem that chaos is degenerated in limited computer precision and Cat map is the small key space, this paper presents a chaotic map based on topological conjugacy and the chaotic characteristics are proved by Devaney definition. In order to produce a large key space, a Cat map named block Cat map is also designed for permutation process based on multiple-dimensional chaotic maps. The image encryption algorithm is based on permutation-substitution, and each key is controlled by different chaotic maps. The entropy analysis, differential analysis, weak-keys analysis, statistical analysis, cipher random analysis, and cipher sensibility analysis depending on key and plaintext are introduced to test the security of the new image encryption scheme. Through the comparison to the proposed scheme with AES, DES and Logistic encryption methods, we come to the conclusion that the image encryption method solves the problem of low precision of one dimensional chaotic function and has higher speed and higher security.

  2. Challenges and mitigation strategies for resist trim etch in resist-mandrel based SAQP integration scheme

    NASA Astrophysics Data System (ADS)

    Mohanty, Nihar; Franke, Elliott; Liu, Eric; Raley, Angelique; Smith, Jeffrey; Farrell, Richard; Wang, Mingmei; Ito, Kiyohito; Das, Sanjana; Ko, Akiteru; Kumar, Kaushik; Ranjan, Alok; O'Meara, David; Nawa, Kenjiro; Scheer, Steven; DeVillers, Anton; Biolsi, Peter

    2015-03-01

    Patterning the desired narrow pitch at 10nm technology node and beyond, necessitates employment of either extreme ultra violet (EUV) lithography or multi-patterning solutions based on 193nm-immersion lithography. With enormous challenges being faced in getting EUV lithography ready for production, multi-patterning solutions that leverage the already installed base of 193nm-immersion-lithography are poised to become the industry norm for 10 and 7nm technology nodes. For patterning sub-40nm pitch line/space features, self-aligned quadruple patterning (SAQP) with resist pattern as the first mandrel shows significant cost as well as design benefit, as compared to EUV lithography or other multi-patterning techniques. One of the most critical steps in this patterning scheme is the resist mandrel definition step which involves trimming / reformation of resist profile via plasma etch for achieving appropriate pitch after the final pattern. Being the first mandrel, the requirements for the Line Edge Roughness (LER) / Line Width Roughness (LWR); critical dimension uniformity (CDU); and profile in 3-dimensions for the resist trim / reformation etch is extremely aggressive. In this paper we highlight the unique challenges associated in developing resist trim / reformation plasma etch process for SAQP integration scheme and summarize our efforts in optimizing the trim etch chemistries, process steps and plasma etch parameters for meeting the mandrel definition targets. Finally, we have shown successful patterning of 30nm pitch patterns via the resist-mandrel SAQP scheme and its implementation for Si-fin formation at 7nm node.

  3. Layered HEVC/H.265 video transmission scheme based on hierarchical QAM optimization

    NASA Astrophysics Data System (ADS)

    Feng, Weidong; Zhou, Cheng; Xiong, Chengyi; Chen, Shaobo; Wang, Junxi

    2015-12-01

    High Efficiency Video Coding (HEVC) is the state-of-art video compression standard which fully support scalability features and is able to generate layered video streams with unequal importance. Unfortunately, when the base layer (BL) which is more importance to the stream is lost during the transmission, the enhancement layer (EL) based on the base layer must be discarded by receiver. Obviously, using the same transmittal strategies for BL and EL is unreasonable. This paper proposed an unequal error protection (UEP) system using different hierarchical amplitude modulation (HQAM). The BL data with high priority are mapped into the most reliable HQAM mode and the EL data with low priority are mapped into HQAM mode with fast transmission efficiency. Simulations on scalable HEVC codec show that the proposed optimized video transmission system is more attractive than the traditional equal error protection (EEP) scheme because it effectively balances the transmission efficiency and reconstruction video quality.

  4. A full potential inverse method based on a density linearization scheme for wing design

    NASA Technical Reports Server (NTRS)

    Shankar, V.

    1982-01-01

    A mixed analysis inverse procedure based on the full potential equation in conservation form was developed to recontour a given base wing to produce density linearization scheme in applying the pressure boundary condition in terms of the velocity potential. The FL030 finite volume analysis code was modified to include the inverse option. The new surface shape information, associated with the modified pressure boundary condition, is calculated at a constant span station based on a mass flux integration. The inverse method is shown to recover the original shape when the analysis pressure is not altered. Inverse calculations for weakening of a strong shock system and for a laminar flow control (LFC) pressure distribution are presented. Two methods for a trailing edge closure model are proposed for further study.

  5. Assessing DRG cost accounting with respect to resource allocation and tariff calculation: the case of Germany

    PubMed Central

    2012-01-01

    The purpose of this paper is to analyze the German diagnosis related groups (G-DRG) cost accounting scheme by assessing its resource allocation at hospital level and its tariff calculation at national level. First, the paper reviews and assesses the three steps in the G-DRG resource allocation scheme at hospital level: (1) the groundwork; (2) cost-center accounting; and (3) patient-level costing. Second, the paper reviews and assesses the three steps in G-DRG national tariff calculation: (1) plausibility checks; (2) inlier calculation; and (3) the “one hospital” approach. The assessment is based on the two main goals of G-DRG introduction: improving transparency and efficiency. A further empirical assessment attests high costing quality. The G-DRG cost accounting scheme shows high system quality in resource allocation at hospital level, with limitations concerning a managerially relevant full cost approach and limitations in terms of advanced activity-based costing at patient-level. However, the scheme has serious flaws in national tariff calculation: inlier calculation is normative, and the “one hospital” model causes cost bias, adjustment and representativeness issues. The G-DRG system was designed for reimbursement calculation, but developed to a standard with strategic management implications, generalized by the idea of adapting a hospital’s cost structures to DRG revenues. This combination causes problems in actual hospital financing, although resource allocation is advanced at hospital level. PMID:22935314

  6. Assessing DRG cost accounting with respect to resource allocation and tariff calculation: the case of Germany.

    PubMed

    Vogl, Matthias

    2012-01-01

    The purpose of this paper is to analyze the German diagnosis related groups (G-DRG) cost accounting scheme by assessing its resource allocation at hospital level and its tariff calculation at national level. First, the paper reviews and assesses the three steps in the G-DRG resource allocation scheme at hospital level: (1) the groundwork; (2) cost-center accounting; and (3) patient-level costing. Second, the paper reviews and assesses the three steps in G-DRG national tariff calculation: (1) plausibility checks; (2) inlier calculation; and (3) the "one hospital" approach. The assessment is based on the two main goals of G-DRG introduction: improving transparency and efficiency. A further empirical assessment attests high costing quality. The G-DRG cost accounting scheme shows high system quality in resource allocation at hospital level, with limitations concerning a managerially relevant full cost approach and limitations in terms of advanced activity-based costing at patient-level. However, the scheme has serious flaws in national tariff calculation: inlier calculation is normative, and the "one hospital" model causes cost bias, adjustment and representativeness issues. The G-DRG system was designed for reimbursement calculation, but developed to a standard with strategic management implications, generalized by the idea of adapting a hospital's cost structures to DRG revenues. This combination causes problems in actual hospital financing, although resource allocation is advanced at hospital level. PMID:22935314

  7. Simulation-based scenario-specific channel modeling for WBAN cooperative transmission schemes.

    PubMed

    Naganawa, Jun-ichi; Wangchuk, Karma; Kim, Minseok; Aoyagi, Takahiro; Takada, Jun-ichi

    2015-03-01

    Wireless body area networks (WBANs) are an emerging technology for realizing efficient healthcare and remote medicine for the aging society of the future. In order to improve the reliability of WBAN systems and support its various applications, channel modeling and performance evaluation are important. This paper proposes a simulation-based channel modeling for evaluating the performance of WBAN cooperative transmission schemes. The time series of path losses among seven on-body nodes are generated by the finite-difference time-domain method for seven body motions. The statistical parameters of the path loss for all the motions are also obtained. The generated path loss is then applied to the evaluation of the two-hop decode-and-forward relaying scheme, yielding an improvement in transmit power. From the evaluation of body motion, useful insights are obtained such as which relay links are more robust than others. Finally, the proposed approach is validated through comparison with a measurement-based approach. PMID:24876134

  8. PSO-tuned PID controller for coupled tank system via priority-based fitness scheme

    NASA Astrophysics Data System (ADS)

    Jaafar, Hazriq Izzuan; Hussien, Sharifah Yuslinda Syed; Selamat, Nur Asmiza; Abidin, Amar Faiz Zainal; Aras, Mohd Shahrieel Mohd; Nasir, Mohamad Na'im Mohd; Bohari, Zul Hasrizal

    2015-05-01

    The industrial applications of Coupled Tank System (CTS) are widely used especially in chemical process industries. The overall process is require liquids to be pumped, stored in the tank and pumped again to another tank. Nevertheless, the level of liquid in tank need to be controlled and flow between two tanks must be regulated. This paper presents development of an optimal PID controller for controlling the desired liquid level of the CTS. Two method of Particle Swarm Optimization (PSO) algorithm will be tested in optimizing the PID controller parameters. These two methods of PSO are standard Particle Swarm Optimization (PSO) and Priority-based Fitness Scheme in Particle Swarm Optimization (PFPSO). Simulation is conducted within Matlab environment to verify the performance of the system in terms of settling time (Ts), steady state error (SSE) and overshoot (OS). It has been demonstrated that implementation of PSO via Priority-based Fitness Scheme (PFPSO) for this system is potential technique to control the desired liquid level and improve the system performances compared with standard PSO.

  9. EEG Classification for Hybrid Brain-Computer Interface Using a Tensor Based Multiclass Multimodal Analysis Scheme

    PubMed Central

    Ji, Hongfei; Li, Jie; Lu, Rongrong; Gu, Rong; Cao, Lei; Gong, Xiaoliang

    2016-01-01

    Electroencephalogram- (EEG-) based brain-computer interface (BCI) systems usually utilize one type of changes in the dynamics of brain oscillations for control, such as event-related desynchronization/synchronization (ERD/ERS), steady state visual evoked potential (SSVEP), and P300 evoked potentials. There is a recent trend to detect more than one of these signals in one system to create a hybrid BCI. However, in this case, EEG data were always divided into groups and analyzed by the separate processing procedures. As a result, the interactive effects were ignored when different types of BCI tasks were executed simultaneously. In this work, we propose an improved tensor based multiclass multimodal scheme especially for hybrid BCI, in which EEG signals are denoted as multiway tensors, a nonredundant rank-one tensor decomposition model is proposed to obtain nonredundant tensor components, a weighted fisher criterion is designed to select multimodal discriminative patterns without ignoring the interactive effects, and support vector machine (SVM) is extended to multiclass classification. Experiment results suggest that the proposed scheme can not only identify the different changes in the dynamics of brain oscillations induced by different types of tasks but also capture the interactive effects of simultaneous tasks properly. Therefore, it has great potential use for hybrid BCI. PMID:26880873

  10. EEG Classification for Hybrid Brain-Computer Interface Using a Tensor Based Multiclass Multimodal Analysis Scheme.

    PubMed

    Ji, Hongfei; Li, Jie; Lu, Rongrong; Gu, Rong; Cao, Lei; Gong, Xiaoliang

    2016-01-01

    Electroencephalogram- (EEG-) based brain-computer interface (BCI) systems usually utilize one type of changes in the dynamics of brain oscillations for control, such as event-related desynchronization/synchronization (ERD/ERS), steady state visual evoked potential (SSVEP), and P300 evoked potentials. There is a recent trend to detect more than one of these signals in one system to create a hybrid BCI. However, in this case, EEG data were always divided into groups and analyzed by the separate processing procedures. As a result, the interactive effects were ignored when different types of BCI tasks were executed simultaneously. In this work, we propose an improved tensor based multiclass multimodal scheme especially for hybrid BCI, in which EEG signals are denoted as multiway tensors, a nonredundant rank-one tensor decomposition model is proposed to obtain nonredundant tensor components, a weighted fisher criterion is designed to select multimodal discriminative patterns without ignoring the interactive effects, and support vector machine (SVM) is extended to multiclass classification. Experiment results suggest that the proposed scheme can not only identify the different changes in the dynamics of brain oscillations induced by different types of tasks but also capture the interactive effects of simultaneous tasks properly. Therefore, it has great potential use for hybrid BCI. PMID:26880873

  11. 24 CFR 574.130 - Formula allocations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Formula allocations. 574.130... URBAN DEVELOPMENT COMMUNITY FACILITIES HOUSING OPPORTUNITIES FOR PERSONS WITH AIDS Formula Entitlements § 574.130 Formula allocations. (a) Data sources. HUD will allocate funds based on the number of cases...

  12. An Improvement of Robust Biometrics-Based Authentication and Key Agreement Scheme for Multi-Server Environments Using Smart Cards

    PubMed Central

    Moon, Jongho; Choi, Younsung; Jung, Jaewook; Won, Dongho

    2015-01-01

    In multi-server environments, user authentication is a very important issue because it provides the authorization that enables users to access their data and services; furthermore, remote user authentication schemes for multi-server environments have solved the problem that has arisen from user’s management of different identities and passwords. For this reason, numerous user authentication schemes that are designed for multi-server environments have been proposed over recent years. In 2015, Lu et al. improved upon Mishra et al.’s scheme, claiming that their remote user authentication scheme is more secure and practical; however, we found that Lu et al.’s scheme is still insecure and incorrect. In this paper, we demonstrate that Lu et al.’s scheme is vulnerable to outsider attack and user impersonation attack, and we propose a new biometrics-based scheme for authentication and key agreement that can be used in multi-server environments; then, we show that our proposed scheme is more secure and supports the required security properties. PMID:26709702

  13. An Improvement of Robust Biometrics-Based Authentication and Key Agreement Scheme for Multi-Server Environments Using Smart Cards.

    PubMed

    Moon, Jongho; Choi, Younsung; Jung, Jaewook; Won, Dongho

    2015-01-01

    In multi-server environments, user authentication is a very important issue because it provides the authorization that enables users to access their data and services; furthermore, remote user authentication schemes for multi-server environments have solved the problem that has arisen from user's management of different identities and passwords. For this reason, numerous user authentication schemes that are designed for multi-server environments have been proposed over recent years. In 2015, Lu et al. improved upon Mishra et al.'s scheme, claiming that their remote user authentication scheme is more secure and practical; however, we found that Lu et al.'s scheme is still insecure and incorrect. In this paper, we demonstrate that Lu et al.'s scheme is vulnerable to outsider attack and user impersonation attack, and we propose a new biometrics-based scheme for authentication and key agreement that can be used in multi-server environments; then, we show that our proposed scheme is more secure and supports the required security properties. PMID:26709702

  14. District Allocation of Human Resources Utilizing the Evidence Based Model: A Study of One High Achieving School District in Southern California

    ERIC Educational Resources Information Center

    Lane, Amber Marie

    2013-01-01

    This study applies the Gap Analysis Framework to understand the gaps that exist in human resource allocation of one Southern California school district. Once identified, gaps are closed with the reallocation of human resources, according to the Evidenced Based Model, requiring the re-purposing of core classroom teachers, specialists, special…

  15. Prioritizing hazardous pollutants in two Nigerian water supply schemes: a risk-based approach

    PubMed Central

    Etchie, Ayotunde T; Etchie, Tunde O; Krishnamurthi, Kannan; SaravanaDevi, S; Wate, Satish R

    2013-01-01

    Abstract Objective To rank pollutants in two Nigerian water supply schemes according to their effect on human health using a risk-based approach. Methods Hazardous pollutants in drinking-water in the study area were identified from a literature search and selected pollutants were monitored from April 2010 to December 2011 in catchments, treatment works and consumer taps. The disease burden due to each pollutant was estimated in disability-adjusted life years (DALYs) using data on the pollutant’s concentration, exposure to the pollutant, the severity of its health effects and the consumer population. Findings The pollutants identified were microbial organisms, cadmium, cobalt, chromium, copper, iron, manganese, nickel, lead and zinc. All were detected in the catchments but only cadmium, cobalt, chromium, manganese and lead exceeded World Health Organization (WHO) guideline values after water treatment. Post-treatment contamination was observed. The estimated disease burden was greatest for chromium in both schemes, followed in decreasing order by cadmium, lead, manganese and cobalt. The total disease burden of all pollutants in the two schemes was 46 000 and 9500 DALYs per year or 0.14 and 0.088 DALYs per person per year, respectively, much higher than the WHO reference level of 1 × 10−6 DALYs per person per year. For each metal, the disease burden exceeded the reference level and was comparable with that due to microbial contamination reported elsewhere in Africa. Conclusion The estimated disease burden of metal contamination of two Nigerian water supply systems was high. It could best be reduced by protection of water catchment and pretreatment by electrocoagulation. PMID:23940402

  16. Suboptimal schemes for atmospheric data assimilation based on the Kalman filter

    NASA Technical Reports Server (NTRS)

    Todling, Ricardo; Cohn, Stephen E.

    1994-01-01

    This work is directed toward approximating the evolution of forecast error covariances for data assimilation. The performance of different algorithms based on simplification of the standard Kalman filter (KF) is studied. These are suboptimal schemes (SOSs) when compared to the KF, which is optimal for linear problems with known statistics. The SOSs considered here are several versions of optimal interpolation (OI), a scheme for height error variance advection, and a simplified KF in which the full height error covariance is advected. To employ a methodology for exact comparison among these schemes, a linear environment is maintained, in which a beta-plane shallow-water model linearized about a constant zonal flow is chosen for the test-bed dynamics. The results show that constructing dynamically balanced forecast error covariances rather than using conventional geostrophically balanced ones is essential for successful performance of any SOS. A posteriori initialization of SOSs to compensate for model - data imbalance sometimes results in poor performance. Instead, properly constructed dynamically balanced forecast error covariances eliminate the need for initialization. When the SOSs studied here make use of dynamically balanced forecast error covariances, the difference among their performances progresses naturally from conventional OI to the KF. In fact, the results suggest that even modest enhancements of OI, such as including an approximate dynamical equation for height error variances while leaving height error correlation structure homogeneous, go a long way toward achieving the performance of the KF, provided that dynamically balanced cross-covariances are constructed and that model errors are accounted for properly. The results indicate that such enhancements are necessary if unconventional data are to have a positive impact.

  17. Experimental demonstration and devices optimization of NRZ-DPSK amplitude regeneration scheme based on SOAs.

    PubMed

    Cao, Tong; Chen, Liao; Yu, Yu; Zhang, Xinliang

    2014-12-29

    We propose and experimentally demonstrate a novel scheme which can simultaneously realize wavelength-preserving and phase-preserving amplitude noise compression of a 40 Gb/s distorted non-return-to-zero differential-phase-shift keying (NRZ-DPSK) signal. In the scheme, two semiconductor optical amplifiers (SOAs) are exploited. The first one (SOA1) is used to generate the inverted signal based on SOA's transient cross-phase modulation (T-XPM) effect and the second one (SOA2) to regenerate the distorted NRZ-DPSK signal using SOA's cross-gain compression (XGC) effect. In the experiment, the bit error ratio (BER) measurements show that power penalties of constructive and destructive demodulation at BER of 10-9 are -1.75 and -1.01 dB, respectively. As the nonlinear effects and the requirements of the two SOAs are completely different, quantum-well (QW) structures has been separately optimized. A complicated theoretical model by combining QW band structure calculation with SOA's dynamic model is exploited to optimize the SOAs, in which both interband effect (carrier density variation) and intraband effect (carrier temperature variation) are taken into account. Regarding SOA1, we choose the tensile strained QW structure and large optical confinement factor to enhance the T-XPM effect. Regarding SOA2, the compressively strained QW structure is selected to reduce the impact of excess phase noise induced by amplitude fluctuations. Exploiting the optimized QW SOAs, better amplitude regeneration performance is demonstrated successfully through numerical simulation. The proposed scheme is intrinsically stable comparing with the interferometer structure and can be integrated on a chip, making it a practical candidate for all-optical amplitude regeneration of high-speed NRZ-DPSK signal. PMID:25607178

  18. 7 CFR 1780.18 - Allocation of program funds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... amounts held in reserve or distributed by base or administrative allocation times the basic State factor... available for allocation−NO reserve−total base and administrative allocations) × SF. (4) Transition formula... program section. (5) Base allocation. An amount that may be allocated to each State dependent upon...

  19. Novel synchronous DPSK optical regenerator based on a feed-forward based carrier extraction scheme.

    PubMed

    Ibrahim, Selwan K; Sygletos, Stylianos; Rafique, Danish; O'Dowd, John A; Weerasuriya, Ruwan; Ellis, Andrew D

    2011-05-01

    We experimentally demonstrate a novel synchronous 10.66 Gbit/s DPSK OEO regenerator which uses a feed-forward carrier extraction scheme with an injection-locked laser to synchronize the regenerated signal wavelength to the incoming signal wavelength. After injection-locking, a low-cost DFB laser used at the regenerator exhibited the same linewidth characteristics as the narrow line-width transmitter laser. The phase regeneration properties of the regenerator were evaluated by emulating random Gaussian phase noise applied to the DPSK signal before the regenerator using a phase modulator driven by an arbitrary waveform generator. The overall performance was evaluated in terms of electrical eye-diagrams, BER measurements, and constellation diagrams. PMID:21643202

  20. Digital image correlation involves an inverse problem: A regularization scheme based on subset size constraint

    NASA Astrophysics Data System (ADS)

    Zhan, Qin; Yuan, Yuan; Fan, Xiangtao; Huang, Jianyong; Xiong, Chunyang; Yuan, Fan

    2016-06-01

    Digital image correlation (DIC) is essentially implicated in a class of inverse problem. Here, a regularization scheme is developed for the subset-based DIC technique to effectively inhibit potential ill-posedness that likely arises in actual deformation calculations and hence enhance numerical stability, accuracy and precision of correlation measurement. With the aid of a parameterized two-dimensional Butterworth window, a regularized subpixel registration strategy is established, in which the amount of speckle information introduced to correlation calculations may be weighted through equivalent subset size constraint. The optimal regularization parameter associated with each individual sampling point is determined in a self-adaptive way by numerically investigating the curve of 2-norm condition number of coefficient matrix versus the corresponding equivalent subset size, based on which the regularized solution can eventually be obtained. Numerical results deriving from both synthetic speckle images and actual experimental images demonstrate the feasibility and effectiveness of the set of newly-proposed regularized DIC algorithms.

  1. SVM-based spectrum mobility prediction scheme in mobile cognitive radio networks.

    PubMed

    Wang, Yao; Zhang, Zhongzhao; Ma, Lin; Chen, Jiamei

    2014-01-01

    Spectrum mobility as an essential issue has not been fully investigated in mobile cognitive radio networks (CRNs). In this paper, a novel support vector machine based spectrum mobility prediction (SVM-SMP) scheme is presented considering time-varying and space-varying characteristics simultaneously in mobile CRNs. The mobility of cognitive users (CUs) and the working activities of primary users (PUs) are analyzed in theory. And a joint feature vector extraction (JFVE) method is proposed based on the theoretical analysis. Then spectrum mobility prediction is executed through the classification of SVM with a fast convergence speed. Numerical results validate that SVM-SMP gains better short-time prediction accuracy rate and miss prediction rate performance than the two algorithms just depending on the location and speed information. Additionally, a rational parameter design can remedy the prediction performance degradation caused by high speed SUs with strong randomness movements. PMID:25143975

  2. Novel image fusion scheme based on maximum ratio combining for robust multispectral face recognition

    NASA Astrophysics Data System (ADS)

    Omri, Faten; Foufou, Sebti

    2015-04-01

    Recently, the research in multispectral face recognition has focused on developing efficient frameworks for improving face recognition performance at close-up distances. However, few studies have investigated the multispectral face images captured at long distance. In fact, great challenges still exist in recognizing human face in images captured at long distance as the image quality might be affected and some important features masked. Therefore, multispectral face recognition tools and algorithms should evolve from close-up distances to long distances. To address these issues, we present in this paper a novel image fusion scheme based on Maximum Ratio Combining algorithm and improve multispectral face recognition at long distance. The proposed method is compared with similar super-resolution method based on the Maximum likelihood algorithm. Simulation results show the efficiency of the proposed approach in term of average variance of detection error.

  3. A Novel Chaotic Map and an Improved Chaos-Based Image Encryption Scheme

    PubMed Central

    2014-01-01

    In this paper, we present a novel approach to create the new chaotic map and propose an improved image encryption scheme based on it. Compared with traditional classic one-dimensional chaotic maps like Logistic Map and Tent Map, this newly created chaotic map demonstrates many better chaotic properties for encryption, implied by a much larger maximal Lyapunov exponent. Furthermore, the new chaotic map and Arnold's Cat Map based image encryption method is designed and proved to be of solid robustness. The simulation results and security analysis indicate that such method not only can meet the requirement of imagine encryption, but also can result in a preferable effectiveness and security, which is usable for general applications. PMID:25143990

  4. P-bRS: a physarum-based routing scheme for wireless sensor networks.

    PubMed

    Zhang, Mingchuan; Wei, Wangyang; Zheng, Ruijuan; Wu, Qingtao

    2014-01-01

    Routing in wireless sensor networks (WSNs) is an extremely challenging issue due to the features of WSNs. Inspired by the large and single-celled amoeboid organism, slime mold Physarum polycephalum, we establish a novel selecting next hop model (SNH). Based on this model, we present a novel Physarum-based routing scheme (P-bRS) for WSNs to balance routing efficiency and energy equilibrium. In P-bRS, a sensor node can choose the proper next hop by using SNH which comprehensively considers the distance, energy residue, and location of the next hop. The simulation results show how P-bRS can achieve the effective trade-off between routing efficiency and energy equilibrium compared to two famous algorithms. PMID:24672326

  5. P-bRS: A Physarum-Based Routing Scheme for Wireless Sensor Networks

    PubMed Central

    Wei, Wangyang; Zheng, Ruijuan; Wu, Qingtao

    2014-01-01

    Routing in wireless sensor networks (WSNs) is an extremely challenging issue due to the features of WSNs. Inspired by the large and single-celled amoeboid organism, slime mold Physarum polycephalum, we establish a novel selecting next hop model (SNH). Based on this model, we present a novel Physarum-based routing scheme (P-bRS) for WSNs to balance routing efficiency and energy equilibrium. In P-bRS, a sensor node can choose the proper next hop by using SNH which comprehensively considers the distance, energy residue, and location of the next hop. The simulation results show how P-bRS can achieve the effective trade-off between routing efficiency and energy equilibrium compared to two famous algorithms. PMID:24672326

  6. Image compression-encryption scheme based on hyper-chaotic system and 2D compressive sensing

    NASA Astrophysics Data System (ADS)

    Zhou, Nanrun; Pan, Shumin; Cheng, Shan; Zhou, Zhihong

    2016-08-01

    Most image encryption algorithms based on low-dimensional chaos systems bear security risks and suffer encryption data expansion when adopting nonlinear transformation directly. To overcome these weaknesses and reduce the possible transmission burden, an efficient image compression-encryption scheme based on hyper-chaotic system and 2D compressive sensing is proposed. The original image is measured by the measurement matrices in two directions to achieve compression and encryption simultaneously, and then the resulting image is re-encrypted by the cycle shift operation controlled by a hyper-chaotic system. Cycle shift operation can change the values of the pixels efficiently. The proposed cryptosystem decreases the volume of data to be transmitted and simplifies the keys distribution simultaneously as a nonlinear encryption system. Simulation results verify the validity and the reliability of the proposed algorithm with acceptable compression and security performance.

  7. Monolithic CEO-stabilization scheme-based frequency comb from an octave-spanning laser

    NASA Astrophysics Data System (ADS)

    Zi-Jiao, Yu; Hai-Nian, Han; Yang, Xie; Hao, Teng; Zhao-Hua, Wang; Zhi-Yi, Wei

    2016-04-01

    We demonstrate a carrier-envelope phase-stabilized octave-spanning oscillator based on the monolithic scheme. A wide output spectrum extending from 480 nm to 1050 nm was generated directly from an all-chirped mirror Ti:sapphire laser. After several improvements, the carrier-envelope offset (CEO) beat frequency accessed nearly 60 dB under a resolution of 100 kHz. Using a feedback system with 50-kHz bandwidth, we compressed the residual phase noise to 55 mrad (integrated from 1 Hz to 1 MHz) for the stabilized CEO, corresponding to 23-as timing jitter at the central wavelength of 790 nm. This is, to the best of our knowledge, the smallest timing jitter achieved among the existing octave-spanning laser based frequency combs. Project supported by the National Basic Research Program of China (Grant No. 2012CB821304) and the National Natural Science Foundation of China (Grant Nos. 11078022 and 61378040).

  8. Studying the effect on system preference by varying coproduct allocation in creating life-cycle inventory.

    PubMed

    Curran, Mary Ann

    2007-10-15

    How one models the input and output data for a life-cycle assessment (LCA) can greatly affect the results. Although much attention has been paid to allocation methodology by researchers in the field, specific guidance is still lacking: Earlier research focused on the effects of applying various allocation schemes to industrial processes when creating life-cycle inventories. To determine the impact of different allocation approaches upon product choice, this study evaluated the gas- and water-phase emissions during the production, distribution, and use of three hypothetical fuel systems (data that represent conventional gasoline and gasoline with 8.7 and 85% ethanol were used as the basis for modeling). This paper presents an explanation of the allocation issue and the results from testing various allocation schemes (weight, volume, market value, energy, and demand-based) when viewed across the entire system. Impact indicators for global warming, ozone depletion, and human health noncancer (water impact) were lower for the ethanol-containing fuels, while impact indicators for acidification, ecotoxicity, eutrophication, human health criteria, and photochemical smog were lower for conventional gasoline (impacts for the water-related human health cancer category showed mixed results). The relative ranking of conventional gasoline in relation to the ethanol-containing fuels was consistent in all instances, suggesting that, in this case study, the choice of allocation methodology had no impact on indicating which fuel has lower environmental impacts. PMID:17993161

  9. Developing an Agent-based Model for the Depot-based Water Allocation System in the Bakken Field in Western North Dakota

    NASA Astrophysics Data System (ADS)

    Lin, T.; Lin, Z.; Lim, S.; Borders, M.

    2015-12-01

    The oil production at the Bakken Shale increased more than ten times from 2008 to 2013 due to technological advancement in hydraulic fracturing and North Dakota has become the second largest oil producing state in the U.S. behind only Texas since 2012. On average it requires about 2-4 million gallons of freshwater to complete one oil well in the Bakken field and the number of oil well completions (i.e., hydraulic fracturing) in the Bakken field increased from 500 in 2008 to 2085 in 2013. A large quantity of freshwater used for hydraulic fracturing renders a significant impact on water resource management in the semi-arid region. A novel water allocation system - water depots - was spontaneously created to distribute surface and ground water for industrial uses. A GIS-based multi-agent model is developed to simulate the emergent patterns and dynamics of the water depot-based water allocation system and to explore its economic and environmental consequences. Four different types of water depot are defined as agents and water price, climate condition, water source, geology, and other physical and economic constraints are considered in the model. Decentralized optimization algorithm will be used to determine the agents' behaviors. The agent-based model for water depots will be coupled with hydrological models to improve the region's water resources management.

  10. Activity-based resource allocation: a system for predicting nursing costs.

    PubMed

    Crockett, M J; DiBlasi, M; Flaherty, P; Sampson, K

    1997-01-01

    As hospital-based managers are being confronted with changing patterns of reimbursement, ranging from revenue generating to cost management, it is imperative that hospitals know the exact nursing costs associated with the actual care delivered to specific patients. Nursing care has traditionally been bundled into the room rate for patients. This approach is extremely limiting when facilities are negotiating per diem rates and capitated rate contracts. At Braintree Hospital Rehabilitation Network, the nursing department has developed and implemented an activity-based management system to determine the actual cost of nursing care provided to each patient. This approach, which differentiates nursing costs accurately by diagnostic group and by intensity of nursing care, has contributed to the hospital's success in negotiating individual patient contracts with insurers in the managed care environment that increasingly focuses on costs and outcomes. Another result has been to enhance the accuracy of the network's cost accounting system. PMID:9416189

  11. Web-based Electronic Sharing and RE-allocation of Assets

    2002-09-09

    The Electronic Asses Sharing Program is a web-based application that provides the capability for complex-wide sharing and reallocation of assets that are excess, under utilized, or un-utilized. through a web-based fron-end and supporting has database with a search engine, users can search for assets that they need, search for assets needed by others, enter assets they need, and enter assets they have available for reallocation. In addition, entire listings of available assets and needed assetsmore » can be viewed. The application is written in Java, the hash database and search engine are in Object-oriented Java Database Management (OJDBM). The application will be hosted on an SRS-managed server outside the Firewall and access will be controlled via a protected realm. An example of the application can be viewed at the followinig (temporary) URL: http://idgdev.srs.gov/servlet/srs.weshare.WeShare« less

  12. Motion-Based Piloted Simulation Evaluation of a Control Allocation Technique to Recover from Pilot Induced Oscillations

    NASA Technical Reports Server (NTRS)

    Craun, Robert W.; Acosta, Diana M.; Beard, Steven D.; Leonard, Michael W.; Hardy, Gordon H.; Weinstein, Michael; Yildiz, Yildiray

    2013-01-01

    This paper describes the maturation of a control allocation technique designed to assist pilots in the recovery from pilot induced oscillations (PIOs). The Control Allocation technique to recover from Pilot Induced Oscillations (CAPIO) is designed to enable next generation high efficiency aircraft designs. Energy efficient next generation aircraft require feedback control strategies that will enable lowering the actuator rate limit requirements for optimal airframe design. One of the common issues flying with actuator rate limits is PIOs caused by the phase lag between the pilot inputs and control surface response. CAPIO utilizes real-time optimization for control allocation to eliminate phase lag in the system caused by control surface rate limiting. System impacts of the control allocator were assessed through a piloted simulation evaluation of a non-linear aircraft simulation in the NASA Ames Vertical Motion Simulator. Results indicate that CAPIO helps reduce oscillatory behavior, including the severity and duration of PIOs, introduced by control surface rate limiting.

  13. Dynamo-based scheme for forecasting the magnitude of solar activity cycles

    NASA Technical Reports Server (NTRS)

    Layden, A. C.; Fox, P. A.; Howard, J. M.; Sarajedini, A.; Schatten, K. H.

    1991-01-01

    This paper presents a general framework for forecasting the smoothed maximum level of solar activity in a given cycle, based on a simple understanding of the solar dynamo. This type of forecasting requires knowledge of the sun's polar magnetic field strength at the preceding activity minimum. Because direct measurements of this quantity are difficult to obtain, the quality of a number of proxy indicators already used by other authors is evaluated, which are physically related to the sun's polar field. These indicators are subjected to a rigorous statistical analysis, and the analysis technique for each indicator is specified in detail in order to simplify and systematize reanalysis for future use. It is found that several of these proxies are in fact poorly correlated or uncorrelated with solar activity, and thus are of little value for predicting activity maxima. Also presented is a scheme in which the predictions of the individual proxies are combined via an appropriately weighted mean to produce a compound prediction. The scheme is then applied to the current cycle 22, and a maximum smoothed international sunspot number of 171 + or - 26 is estimated.

  14. A study of design approach of spreading schemes for viral marketing based on human dynamics

    NASA Astrophysics Data System (ADS)

    Yang, Jianmei; Zhuang, Dong; Xie, Weicong; Chen, Guangrong

    2013-12-01

    Before launching a real viral marketing campaign, it is needed to design a spreading scheme by simulations. Based on a categorization of spreading patterns in real world and models, we point out that the existing research (especially Yang et al. (2010) Ref. [16]) implicitly assume that if a user decides to post a received message (is activated), he/she will take the reposting action promptly (Prompt Action After Activation, or PAAA). After a careful analysis on a real dataset however, it is found that the observed time differences between action and activation exhibit a heavy-tailed distribution. A simulation model for heavy-tailed pattern is then proposed and performed. Similarities and differences of spreading processes between the heavy-tailed and PAAA patterns are analyzed. Consequently, a more practical design approach of spreading scheme for viral marketing on QQ platform is proposed. The design approach can be extended and applied to the contexts of non-heavy-tailed pattern, and viral marketing on other instant messaging platforms.

  15. A new genotyping scheme based on MLVA for inter-laboratory surveillance of Streptococcus pyogenes.

    PubMed

    Imperi, Monica; Pittiglio, Valentina; D'Avenio, Giuseppe; Gherardi, Giovanni; Ciammaruconi, Andrea; Lista, Florigio; Pourcel, Christine; Baldassarri, Lucilla; Creti, Roberta

    2016-08-01

    A newly developed MLVA seven-loci scheme for Streptococcus pyogenes is described. The method can be successfully applied by using both agarose gel with visual inspections of bands and Lab on Chip technology. The potential of the present MLVA has been tested on a collection of 100 clinical GAS strains representing the most common emm types found in high-income countries plus 18 published gap-free genomes, in comparison to PFGE and MLST. The MLVA analysis defined 30 MLVA types with ten out of the considered 15 emm types exhibiting multiple and specific MLVA types. In only one occasion the same MLVA profile was shared between isolates belonging to two different emm types. A robust congruency between the methods was observed, with MLVA discriminating within clonal complexes as defined by PFGE or MLST. This new MLVA scheme can be adopted as a quick, low-cost and reliable typing method to track the short-term diffusion of GAS clones in inter-laboratory-based surveillance. PMID:27302039

  16. A Wireless Sensor Network Based Personnel Positioning Scheme in Coal Mines with Blind Areas

    PubMed Central

    Liu, Zhigao; Li, Chunwen; Wu, Danchen; Dai, Wenhan; Geng, Shaobo; Ding, Qingqing

    2010-01-01

    This paper proposes a novel personnel positioning scheme for a tunnel network with blind areas, which compared with most existing schemes offers both low-cost and high-precision. Based on the data models of tunnel networks, measurement networks and mobile miners, the global positioning method is divided into four steps: (1) calculate the real time personnel location in local areas using a location engine, and send it to the upper computer through the gateway; (2) correct any localization errors resulting from the underground tunnel environmental interference; (3) determine the global three-dimensional position by coordinate transformation; (4) estimate the personnel locations in the blind areas. A prototype system constructed to verify the positioning performance shows that the proposed positioning system has good reliability, scalability, and positioning performance. In particular, the static localization error of the positioning system is less than 2.4 m in the underground tunnel environment and the moving estimation error is below 4.5 m in the corridor environment. The system was operated continuously over three months without any failures. PMID:22163446

  17. A sparse Bayesian learning based scheme for multi-movement recognition using sEMG.

    PubMed

    Ding, Shuai; Wang, Liang

    2016-03-01

    This paper proposed a feature extraction scheme based on sparse representation considering the non-stationary property of surface electromyography (sEMG). Sparse Bayesian learning was introduced to extract the feature with optimal class separability to improve recognition accuracy of multi-movement patterns. The extracted feature, sparse representation coefficients (SRC), represented time-varying characteristics of sEMG effectively because of the compressibility (or weak sparsity) of the signal in some transformed domains. We investigated the effect of the proposed feature by comparing with other fourteen individual features in offline recognition. The results demonstrated the proposed feature revealed important dynamic information in the sEMG signals. The multi-feature sets formed by the SRC and other single feature yielded more superior performance on recognition accuracy, compared with the single features. The best average recognition accuracy of 94.33 % was gained by using SVM classifier with the multi-feature set combining the feature SRC, Williston amplitude (WAMP), wavelength (WL) and the coefficients of the fourth order autoregressive model (ARC4) via multiple kernel learning framework. The proposed feature extraction scheme (known as SRC + WAMP + WL + ARC4) is a promising method for multi-movement recognition with high accuracy. PMID:26577712

  18. Photovoltaic array driven adjustable speed heat pump and power system scheme for a lunar based habitat

    SciTech Connect

    Domijan, A. Jr.; Buchh, T.A.

    1998-12-01

    A high reliability power system scheme, incorporating a photovoltaic power supply and adjustable speed heat pump for life support is presented in this paper. Initial design guidelines and also a description of the state of technology available is presented herein. The power supply scheme will be used as input to an Adjustable Speed Drive (ASD) which will be driving a heat pump. A brief study of various aspects of ASDs is presented, further a summary of the relative merits of different ASD systems presently in vogue is discussed. The advantages of using microcomputer based ASDs is widely understood and accepted. Of the three most popular drive systems, namely the Induction Motor Drive, Switched Reluctance Motor Drive and Brushless DC Motor Drive, any one may be chosen. The choice would depend on the nature of the application and its requirements. The suitability of the above mentioned drive systems and control techniques for a photovoltaic array driven ASD for an aerospace application are discussed. Also discussed are several possible power system designs for a potential lunar habitat.

  19. An improved high-order scheme for DNS of low Mach number turbulent reacting flows based on stiff chemistry solver

    NASA Astrophysics Data System (ADS)

    Yu, Rixin; Yu, Jiangfei; Bai, Xue-Song

    2012-06-01

    We present an improved numerical scheme for numerical simulations of low Mach number turbulent reacting flows with detailed chemistry and transport. The method is based on a semi-implicit operator-splitting scheme with a stiff solver for integration of the chemical kinetic rates, developed by Knio et al. [O.M. Knio, H.N. Najm, P.S. Wyckoff, A semi-implicit numerical scheme for reacting flow II. Stiff, operator-split formulation, Journal of Computational Physics 154 (2) (1999) 428-467]. Using the material derivative form of continuity equation, we enhance the scheme to allow for large density ratio in the flow field. The scheme is developed for direct numerical simulation of turbulent reacting flow by employing high-order discretization for the spatial terms. The accuracy of the scheme in space and time is verified by examining the grid/time-step dependency on one-dimensional benchmark cases: a freely propagating premixed flame in an open environment and in an enclosure related to spark-ignition engines. The scheme is then examined in simulations of a two-dimensional laminar flame/vortex-pair interaction. Furthermore, we apply the scheme to direct numerical simulation of a homogeneous charge compression ignition (HCCI) process in an enclosure studied previously in the literature. Satisfactory agreement is found in terms of the overall ignition behavior, local reaction zone structures and statistical quantities. Finally, the scheme is used to study the development of intrinsic flame instabilities in a lean H2/air premixed flame, where it is shown that the spatial and temporary accuracies of numerical schemes can have great impact on the prediction of the sensitive nonlinear evolution process of flame instability.

  20. Risk-based decision making for staggered bioterrorist attacks : resource allocation and risk reduction in "reload" scenarios.

    SciTech Connect

    Lemaster, Michelle Nicole; Gay, David M.; Ehlen, Mark Andrew; Boggs, Paul T.; Ray, Jaideep

    2009-10-01

    Staggered bioterrorist attacks with aerosolized pathogens on population centers present a formidable challenge to resource allocation and response planning. The response and planning will commence immediately after the detection of the first attack and with no or little information of the second attack. In this report, we outline a method by which resource allocation may be performed. It involves probabilistic reconstruction of the bioterrorist attack from partial observations of the outbreak, followed by an optimization-under-uncertainty approach to perform resource allocations. We consider both single-site and time-staggered multi-site attacks (i.e., a reload scenario) under conditions when resources (personnel and equipment which are difficult to gather and transport) are insufficient. Both communicable (plague) and non-communicable diseases (anthrax) are addressed, and we also consider cases when the data, the time-series of people reporting with symptoms, are confounded with a reporting delay. We demonstrate how our approach develops allocations profiles that have the potential to reduce the probability of an extremely adverse outcome in exchange for a more certain, but less adverse outcome. We explore the effect of placing limits on daily allocations. Further, since our method is data-driven, the resource allocation progressively improves as more data becomes available.

  1. Equality of Medical Health Resource Allocation in China Based on the Gini Coefficient Method

    PubMed Central

    JIN, Jian; WANG, Jianxiang; MA, Xiaoyi; WANG, Yuding; LI, Renyong

    2015-01-01

    Background: The Chinese government is trying to achieve the goal of “universal access to basic health care services”. However, the inequality of the distribution of health care resources across the country is the biggest obstacle. This paper aims to explore these inequalities and the extent to which the method of analysis influences the perception. Methods: The indicators of health care resource distribution studied consisted of the number of health care institutions, the number of beds in health care institutions and the number of medical personnel. Data were obtained from the China Statistical Yearbook 2014. The extent of equality was assessed using the Lorenz Curve and Gini Coefficient Method. Results: Health care resource distribution in China demonstrates inequalities. The demographic Gini Coefficients based on the Lorenz Curves for the distribution of health care institutions, beds in health care institutions and medical personnel are 0.190, 0.070 and 0.070 respectively, while the corresponding Coefficients based on geographical areas are 0.616, 0.639 and 0.650. Conclusion: The equality of China’s demographically assessed distribution of health care resources is greater than that of its geographically measured distribution. Coefficients expressed by population imply there is ready access to healthcare in all regions, whilst the Coefficients by geographical area apparently indicate inequality. This is the result of the sparsity of population. PMID:26056663

  2. Rationally designed donor-acceptor scheme based molecules for applications in opto-electronic devices.

    PubMed

    Subash Sundar, T; Sen, R; Johari, P

    2016-04-01

    Several donor (D)-acceptor (A) based molecules are rationally designed by adopting three different schemes in which the conjugation length, strength of the donor and acceptor moieties, and planarity of the molecules are varied. These variations are made by introducing a π-conjugated linkage unit, terminating the ends of the moieties by different electron donating and accepting functional groups, and fusing the donor and acceptor moieties, respectively. Our DFT and TDDFT based calculations reveal that using the above-mentioned design schemes, the electronic and optical properties of the D-A based molecules can be largely tuned. While introduction of a linkage and fusing of moieties enhance the π-π interaction, addition of electron donating groups (-CH3, -OH, and -NH2) and electron accepting groups (-CF3, -CN, -NO2, and -NH3(+)) varies the strength of the donor and acceptor moieties. These factors lead to modulation of the HOMO and LUMO energy levels and facilitate the engineering of the HOMO-LUMO gap and the optical gap over a wide range of ∼0.7-3.7 eV. Moreover, on the basis of calculated ionization potential and reorganization energy, most of the investigated molecules are predicted to be air stable and to exhibit high electron mobility, with the possibility of the presence of ambipolar characteristics in a few of them. The results of our calculations not only demonstrate the examined molecules to be the potential materials for organic opto-electronic devices, but also establish an understanding of the composition-structure-property correlation, which will provide guidelines for designing and synthesizing new materials of choice. PMID:26972386

  3. New classification scheme for ozone monitoring stations based on frequency distribution of hourly data.

    PubMed

    Tapia, O; Escudero, M; Lozano, Á; Anzano, J; Mantilla, E

    2016-02-15

    According to European Union (EU) legislation, ozone (O3) monitoring sites can be classified regarding their location (rural background, rural, suburban, urban) or based on the presence of emission sources (background, traffic, industrial). There have been attempts to improve these classifications aiming to reduce their ambiguity and subjectivity, but although scientifically sound, they lack the simplicity needed for operational purposes. We present a simple methodology for classifying O3 stations based on the characteristics of frequency distribution curves which are indicative of the actual impact of combustion sources emitting NO that consumes O3 via titration. Four classes are identified using 1998-2012 hourly data from 72 stations widely distributed in mainland Spain and the Balearic Islands. Types 1 and 2 present unimodal bell-shaped distribution with very low amount of data near zero reflecting a limited influence of combustion sources while Type 4 has a primary mode close to zero, showing the impact of combustion sources, and a minor mode for higher concentrations. Type 3 stations present bimodal distributions with the main mode in the higher levels. We propose a quantitative metric based on the Gini index with the objective of reproducing this classification and finding empirical ranges potentially useful for future classifications. The analysis of the correspondence with the EUROAIRNET classes for the 72 stations reveals that the proposed scheme is only dependent on the impact of combustion sources and not on climatic or orographic aspects. It is demonstrated that this classification is robust since in 87% of the occasions the classification obtained for individual years coincide with the global classification obtained for the 1998-2012 period. Finally, case studies showing the applicability of the new classification scheme for assessing the impact on O3 of a station relocation and performing a critical evaluation of an air quality monitoring network are

  4. Agent based model of effects of task allocation strategies in flat organizations

    NASA Astrophysics Data System (ADS)

    Sobkowicz, Pawel

    2016-09-01

    A common practice in many organizations is to pile the work on the best performers. It is easy to implement by the management and, despite the apparent injustice, appears to be working in many situations. In our work we present a simple agent based model, constructed to simulate this practice and to analyze conditions under which the overall efficiency of the organization (for example measured by the backlog of unresolved issues) breaks down, due to the cumulative effect of the individual overloads. The model confirms that the strategy mentioned above is, indeed, rational: it leads to better global results than an alternative one, using equal workload distribution among all workers. The presented analyses focus on the behavior of the organizations close to the limit of the maximum total throughput and provide results for the growth of the unprocessed backlog in several situations, as well as suggestions related to avoiding such buildup.

  5. Dynamic resource allocation engine for cloud-based real-time video transcoding in mobile cloud computing environments

    NASA Astrophysics Data System (ADS)

    Adedayo, Bada; Wang, Qi; Alcaraz Calero, Jose M.; Grecos, Christos

    2015-02-01

    The recent explosion in video-related Internet traffic has been driven by the widespread use of smart mobile devices, particularly smartphones with advanced cameras that are able to record high-quality videos. Although many of these devices offer the facility to record videos at different spatial and temporal resolutions, primarily with local storage considerations in mind, most users only ever use the highest quality settings. The vast majority of these devices are optimised for compressing the acquired video using a single built-in codec and have neither the computational resources nor battery reserves to transcode the video to alternative formats. This paper proposes a new low-complexity dynamic resource allocation engine for cloud-based video transcoding services that are both scalable and capable of being delivered in real-time. Firstly, through extensive experimentation, we establish resource requirement benchmarks for a wide range of transcoding tasks. The set of tasks investigated covers the most widely used input formats (encoder type, resolution, amount of motion and frame rate) associated with mobile devices and the most popular output formats derived from a comprehensive set of use cases, e.g. a mobile news reporter directly transmitting videos to the TV audience of various video format requirements, with minimal usage of resources both at the reporter's end and at the cloud infrastructure end for transcoding services.

  6. An Innovative Time-Cost-Quality Tradeoff Modeling of Building Construction Project Based on Resource Allocation

    PubMed Central

    2014-01-01

    The time, quality, and cost are three important but contradictive objectives in a building construction project. It is a tough challenge for project managers to optimize them since they are different parameters. This paper presents a time-cost-quality optimization model that enables managers to optimize multiobjectives. The model is from the project breakdown structure method where task resources in a construction project are divided into a series of activities and further into construction labors, materials, equipment, and administration. The resources utilized in a construction activity would eventually determine its construction time, cost, and quality, and a complex time-cost-quality trade-off model is finally generated based on correlations between construction activities. A genetic algorithm tool is applied in the model to solve the comprehensive nonlinear time-cost-quality problems. Building of a three-storey house is an example to illustrate the implementation of the model, demonstrate its advantages in optimizing trade-off of construction time, cost, and quality, and help make a winning decision in construction practices. The computational time-cost-quality curves in visual graphics from the case study prove traditional cost-time assumptions reasonable and also prove this time-cost-quality trade-off model sophisticated. PMID:24672351

  7. A hybrid lightwave transport system based on a BLS with an OSNR enhancement scheme

    NASA Astrophysics Data System (ADS)

    Ying, Cheng-Ling; Lu, Hai-Han; Li, Chung-Yi; Lin, Chun-Yu; Wu, Chang-Jen; Lin, Hung-Hsien

    2016-04-01

    A hybrid lightwave transport system based on a broadband light source (BLS) with an optical signal-to-noise ratio (OSNR) enhancement scheme for millimeter-wave (MMW)/radio-over-fiber (RoF)/cable television (CATV) signal transmission is proposed and experimentally demonstrated. Unlike traditional hybrid lightwave transport systems for signal transmission, in which a transmitting site needs multiple wavelength-selected distributed feedback laser diodes (DFB LDs) to support various services, such proposed systems employ a phase modulator to provide multiple optical carriers for various applications. Over an 80 km single-mode fiber (SMF) transmission, the bit error rate (BER)/carrier-to-noise ratio (CNR)/composite second-order (CSO)/composite triple-beat (CTB) perform brilliantly for hybrid 100 GHz MMW/50 GHz MMW/10 GHz RoF/550 MHz CATV signal transmission. Such a hybrid lightwave transport system would be attractive for fiber trunk applications to provide broadband integrated services.

  8. Fuzzy-Wavelet Based Double Line Transmission System Protection Scheme in the Presence of SVC

    NASA Astrophysics Data System (ADS)

    Goli, Ravikumar; Shaik, Abdul Gafoor; Tulasi Ram, Sankara S.

    2014-07-01

    Increasing the power transfer capability and efficient utilization of available transmission lines, improving the power system controllability and stability, power oscillation damping and voltage compensation have made strides and created Flexible AC Transmission (FACTS) devices in recent decades. Shunt FACTS devices can have adverse effects on distance protection both in steady state and transient periods. Severe under reaching is the most important problem of relay which is caused by current injection at the point of connection to the system. Current absorption of compensator leads to overreach of relay. This work presents an efficient method based on wavelet transforms, fault detection, classification and location using Fuzzy logic technique which is almost independent of fault impedance, fault distance and fault inception angle. The proposed protection scheme is found to be fast, reliable and accurate for various types of faults on transmission lines with and without Static Var compensator at different locations and with various incidence angles.

  9. Evidence-based decision-making within Australia's pharmaceutical benefits scheme.

    PubMed

    Lopert, Ruth

    2009-07-01

    In Australia, most prescription drugs are subsidized through the Pharmaceutical Benefits Scheme (PBS), one of several government programs in which evidence-based decision making is applied to the funding of health technologies. PBS processes are intended to ensure "value for money" for the Australian taxpayer and to support affordable, equitable access to prescription medicines; they are not intended as a mechanism for cost containment. The inclusion of a drug on the national formulary depends on the recommendation of the Pharmaceutical Benefits Advisory Committee (PBAC), which considers not only the comparative effectiveness but also the comparative cost-effectiveness of drugs proposed for listing. While some decisions have been controversial, the PBS retains strong public support. Moreover, evidence does not suggest that the consideration of cost-effectiveness has created a negative environment for the drug industry: Australia has a high penetration of patented medicines, with prices for some recently approved drugs at U.S. levels. PMID:19639714

  10. All-optical analog-to-digital conversion scheme based on Sagnac loop and balanced receivers.

    PubMed

    Xu, Kun; Niu, Jian; Dai, Yitang; Sun, Xiaoqiang; Dai, Jian; Wu, Jian; Lin, Jintong

    2011-05-10

    An all-optical analog-to-digital conversion scheme based on a Sagnac loop and balanced receivers is proposed and experimentally demonstrated. Adjustable phase shift about the transfer function of the Sagnac loop is obtained by using the multiwavelength optical pulses to realize the phase-shift optical quantization. Benefit from the complementary outputs at the transmitted and reflected ports of the Sagnac loop and balanced receiver can be used to obtain the quantized output binary signal for the encoding operation. A proof-of-concept experiment is implemented using a wavelength tunable continuous-wave laser diode. Using 16 different wavelengths, the 16 quantization levels are demonstrated and an effective number of bits (ENOB) of 4 bits is obtained. PMID:21556099

  11. A multichannel EEG acquisition scheme based on single ended amplifiers and digital DRL.

    PubMed

    Haberman, Marcelo Alejandro; Spinelli, Enrique Mario

    2012-12-01

    Single ended (SE) amplifiers allow implementing biopotential front-ends with a reduced number of parts, being well suited for preamplified electrodes or compact EEG headboxes. On the other hand, given that each channel has independent gain; mismatching between these gains results in poor common-mode rejection ratios (CMRRs) (about 30 dB considering 1% tolerance components). This work proposes a scheme for multichannel EEG acquisition systems based on SE amplifiers and a novel digital driven right leg (DDRL) circuit, which overcome the poor CMRR of the front-end stage providing a high common mode reduction at power line frequency (up to 80 dB). A functional prototype was built and tested showing the feasibility of the proposed technique. It provided EEG records with negligible power line interference, even in very aggressive EMI environments. PMID:23853262

  12. Optical threshold secret sharing scheme based on basic vector operations and coherence superposition

    NASA Astrophysics Data System (ADS)

    Deng, Xiaopeng; Wen, Wei; Mi, Xianwu; Long, Xuewen

    2015-04-01

    We propose, to our knowledge for the first time, a simple optical algorithm for secret image sharing with the (2,n) threshold scheme based on basic vector operations and coherence superposition. The secret image to be shared is firstly divided into n shadow images by use of basic vector operations. In the reconstruction stage, the secret image can be retrieved by recording the intensity of the coherence superposition of any two shadow images. Compared with the published encryption techniques which focus narrowly on information encryption, the proposed method can realize information encryption as well as secret sharing, which further ensures the safety and integrality of the secret information and prevents power from being kept centralized and abused. The feasibility and effectiveness of the proposed method are demonstrated by numerical results.

  13. Virtual Reality-based Telesurgery via Teleprogramming Scheme Combined with Semi-autonomous Control.

    PubMed

    Zhijiang, Du; Zhiheng, Jia; Minxiu, Kong

    2005-01-01

    Telesurgery systems have long been suffering variable and unpredictable Internet commutation time delay, operation fatigue, and other drawbacks. Based on virtual reality technology, a teleprogramming scheme combined with semi-autonomous control is introduced to guarantee the robustness and efficiency of teleoperation of HIT-RAOS, a robot-assisted orthopedic surgery system. In this system, without considering time delay, the operator can just interact with virtual environment which provides real-time 3D vision, stereophonic sound, and tactile and force feedback imitated by a parallel master manipulator. And several tasks can be managed simultaneously via semi-autonomous control. Finally, the method is experimentally demonstrated on an experiment of locking of intramedullary nails, and is shown to effectively provide stability and performances. PMID:17282656

  14. ROCIT : a visual object recognition algorithm based on a rank-order coding scheme.

    SciTech Connect

    Gonzales, Antonio Ignacio; Reeves, Paul C.; Jones, John J.; Farkas, Benjamin D.

    2004-06-01

    This document describes ROCIT, a neural-inspired object recognition algorithm based on a rank-order coding scheme that uses a light-weight neuron model. ROCIT coarsely simulates a subset of the human ventral visual stream from the retina through the inferior temporal cortex. It was designed to provide an extensible baseline from which to improve the fidelity of the ventral stream model and explore the engineering potential of rank order coding with respect to object recognition. This report describes the baseline algorithm, the model's neural network architecture, the theoretical basis for the approach, and reviews the history of similar implementations. Illustrative results are used to clarify algorithm details. A formal benchmark to the 1998 FERET fafc test shows above average performance, which is encouraging. The report concludes with a brief review of potential algorithmic extensions for obtaining scale and rotational invariance.

  15. Microeconomics-based resource allocation in overlay networks by using non-strategic behavior modeling

    NASA Astrophysics Data System (ADS)

    Analoui, Morteza; Rezvani, Mohammad Hossein

    2011-01-01

    Behavior modeling has recently been investigated for designing self-organizing mechanisms in the context of communication networks in order to exploit the natural selfishness of the users with the goal of maximizing the overall utility. In strategic behavior modeling, the users of the network are assumed to be game players who seek to maximize their utility with taking into account the decisions that the other players might make. The essential difference between the aforementioned researches and this work is that it incorporates the non-strategic decisions in order to design the mechanism for the overlay network. In this solution concept, the decisions that a peer might make does not affect the actions of the other peers at all. The theory of consumer-firm developed in microeconomics is a model of the non-strategic behavior that we have adopted in our research. Based on it, we have presented distributed algorithms for peers' "joining" and "leaving" operations. We have modeled the overlay network as a competitive economy in which the content provided by an origin server can be viewed as commodity and the origin server and the peers who multicast the content to their downside are considered as the firms. On the other hand, due to the dual role of the peers in the overlay network, they can be considered as the consumers as well. On joining to the overlay economy, each peer is provided with an income and tries to get hold of the service regardless to the behavior of the other peers. We have designed the scalable algorithms in such a way that the existence of equilibrium price (known as Walrasian equilibrium price) is guaranteed.

  16. Are pharmacy-based minor ailment schemes a substitute for other service providers?

    PubMed Central

    Paudyal, Vibhu; Watson, Margaret C; Sach, Tracey; Porteous, Terry; Bond, Christine M; Wright, David J; Cleland, Jennifer; Barton, Garry; Holland, Richard

    2013-01-01

    Background Pharmacy-based minor ailment schemes (PMASs) have been introduced throughout the UK to reduce the burden of minor ailments on high-cost settings, including general practice and emergency departments. Aim This study aimed to explore the effect of PMASs on patient health- and cost-related outcomes; and their impact on general practices. Design and setting Community pharmacy-based systematic review. Method Standard systematic review methods were used, including searches of electronic databases, and grey literature from 2001 to 2011, imposing no restrictions on language or study design. Reporting was conducted in the form recommended in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and checklist. Results Thirty-one evaluations were included from 3308 titles identified. Reconsultation rates in general practice, following an index consultation with a PMAS, ranged from 2.4% to 23.4%. The proportion of patients reporting complete resolution of symptoms after an index PMAS consultation ranged from 68% to 94%. No study included a full economic evaluation. The mean cost per PMAS consultation ranged from £1.44 to £15.90. The total number of consultations and prescribing for minor ailments at general practices often declined following the introduction of PMAS. Conclusion Low reconsultation and high symptom-resolution rates suggest that minor ailments are being dealt with appropriately by PMASs. PMAS consultations are less expensive than consultations with GPs. The extent to which these schemes shift demand for management of minor ailments away from high-cost settings has not been fully determined. This evidence suggests that PMASs provide a suitable alternative to general practice consultations. Evidence from economic evaluations is needed to inform the future delivery of PMASs. PMID:23834884

  17. Assessing lidar-based classification schemes for polar stratospheric clouds based on 16 years of measurements at Esrange, Sweden

    NASA Astrophysics Data System (ADS)

    Achtert, P.; Tesche, M.

    2014-02-01

    Lidar measurements of polar stratospheric clouds (PSCs) are commonly analyzed in classification schemes that apply the backscatter ratio and the particle depolarization ratio. This similarity of input data suggests comparable results of different classification schemes—despite measurements being performed with a variety of mostly custom-made instruments. Based on a time series of 16 years of lidar measurements at Esrange (68°N, 21°E), Sweden, we show that PSC classification differs substantially depending on the applied scheme. The discrepancies result from varying threshold values of lidar-derived parameters used to define certain PSC types. The resulting inconsistencies could impact the understanding of long-term PSC observations documented in the literature. We identify two out of seven considered classification schemes that are most likely to give reliable results and should be used in future lidar-based studies. Using polarized backscatter ratios gives the advantage of increased contrast for observations of weakly backscattering and weakly depolarizing particles. Improved confidence in PSC classification can be achieved by a more comprehensive consideration of the effect of measurement uncertainties. The particle depolarization ratio is the key to a reliable identification of different PSC types. Hence, detailed information on the calibration of the polarization-sensitive measurement channels should be provided to assess the findings of a study. Presently, most PSC measurements with lidar are performed at 532 nm only. The information from additional polarization-sensitive measurements in the near infrared could lead to an improved PSC classification. Coincident lidar-based temperature measurements at PSC level might provide useful information for an assessment of PSC classification.

  18. Artificial intelligent techniques for optimizing water allocation in a reservoir watershed

    NASA Astrophysics Data System (ADS)

    Chang, Fi-John; Chang, Li-Chiu; Wang, Yu-Chung

    2014-05-01

    This study proposes a systematical water allocation scheme that integrates system analysis with artificial intelligence techniques for reservoir operation in consideration of the great uncertainty upon hydrometeorology for mitigating droughts impacts on public and irrigation sectors. The AI techniques mainly include a genetic algorithm and adaptive-network based fuzzy inference system (ANFIS). We first derive evaluation diagrams through systematic interactive evaluations on long-term hydrological data to provide a clear simulation perspective of all possible drought conditions tagged with their corresponding water shortages; then search the optimal reservoir operating histogram using genetic algorithm (GA) based on given demands and hydrological conditions that can be recognized as the optimal base of input-output training patterns for modelling; and finally build a suitable water allocation scheme through constructing an adaptive neuro-fuzzy inference system (ANFIS) model with a learning of the mechanism between designed inputs (water discount rates and hydrological conditions) and outputs (two scenarios: simulated and optimized water deficiency levels). The effectiveness of the proposed approach is tested on the operation of the Shihmen Reservoir in northern Taiwan for the first paddy crop in the study area to assess the water allocation mechanism during drought periods. We demonstrate that the proposed water allocation scheme significantly and substantially avails water managers of reliably determining a suitable discount rate on water supply for both irrigation and public sectors, and thus can reduce the drought risk and the compensation amount induced by making restrictions on agricultural use water.

  19. Resolved rate and torque control schemes for large scale space based kinematically redundant manipulators

    NASA Technical Reports Server (NTRS)

    Bailey, Robert W.; Quiocho, Leslie J.

    1991-01-01

    Resolved rate control of kinematically redundant ground based manipulators is a challenging problem. The structural, actuator, and control loop frequency characteristics of industrial grade robots generally allow operation with resolved rate control; a rate command is achievable with good accuracy. However, space based manipulators are different, typically have less structural stiffness, more motor and joint friction, and lower control loop cycle frequencies. These undesirable characteristics present a considerable Point of Resolution (POR) control problem for space based, kinematically redundant manipulators for the following reason: a kinematically redundant manipulator requires an arbitrary constraint to solve for the joint rate commands. A space manipulator will not respond to joint rate commands because of these characteristics. A space based manipulator simulation, including free end rigid body dynamics, motor dynamics, motor striction/friction, gearbox backlash, joint striction/friction, and Space Station Remote Manipulator System type configuration parameters, is used to evaluate the performance of a documented resolved rate control law. Alternate schemes which include torque control are also evaluated.

  20. Arbitrated quantum signature scheme based on χ-type entangled states

    NASA Astrophysics Data System (ADS)

    Zuo, Huijuan; Huang, Wei; Qin, Sujuan

    2013-10-01

    An arbitrated quantum signature scheme, which is mainly applied in electronic-payment systems, is proposed and investigated. The χ-type entangled states are used for quantum key distribution and quantum signature in this protocol. Compared with previous quantum signature schemes which also utilize χ-type entangled states, the proposed scheme provides higher efficiency. Finally, we also analyze its security under various kinds of attacks.

  1. Understanding the impacts of allocation approaches during process-based life cycle assessment of water treatment chemicals.

    PubMed

    Alvarez-Gaitan, Juan P; Peters, Gregory M; Short, Michael D; Schulz, Matthias; Moore, Stephen

    2014-01-01

    Chemicals are an important component of advanced water treatment operations not only in terms of economics but also from an environmental standpoint. Tools such as life cycle assessment (LCA) are useful for estimating the environmental impacts of water treatment operations. At the same time, LCA analysts must manage several fundamental and as yet unresolved methodological challenges, one of which is the question of how best to "allocate" environmental burdens in multifunctional processes. Using water treatment chemicals as a case study example, this article aims to quantify the variability in greenhouse gas emissions estimates stemming from methodological choices made in respect of allocation during LCA. The chemicals investigated and reported here are those most important to coagulation and disinfection processes, and the outcomes are illustrated on the basis of treating 1000 ML of noncoagulated and nondisinfected water. Recent process and economic data for the production of these chemicals is used and methodological alternatives for solving the multifunctionality problem, including system expansion and mass, exergy, and economic allocation, are applied to data from chlor-alkali plants. In addition, Monte Carlo simulation is included to provide a comprehensive picture of the robustness of economic allocation results to changes in the market price of these industrial commodities. For disinfection, results demonstrate that chlorine gas has a lower global warming potential (GWP) than sodium hypochlorite regardless of the technique used to solve allocation issues. For coagulation, when mass or economic allocation is used to solve the multifunctionality problem in the chlor-alkali facility, ferric chloride was found to have a higher GWP than aluminum sulfate and a slightly lower burden where system expansion or exergy allocation are applied instead. Monte Carlo results demonstrate that when economic allocation is used, GWP results were relatively robust and resilient

  2. Wireless Networks with Energy Harvesting and Power Transfer: Joint Power and Time Allocation

    NASA Astrophysics Data System (ADS)

    Hadzi-Velkov, Zoran; Nikoloska, Ivana; Karagiannidis, George K.; Duong, Trung Q.

    2016-01-01

    In this paper, we consider wireless powered communication networks which could operate perpetually, as the base station (BS) broadcasts energy to the multiple energy harvesting (EH) information transmitters. These employ "harvest then transmit" mechanism, as they spend all of their energy harvested during the previous BS energy broadcast to transmit the information towards the BS. Assuming time division multiple access (TDMA), we propose a novel transmission scheme for jointly optimal allocation of the BS broadcasting power and time sharing among the wireless nodes, which maximizes the overall network throughput, under the constraint of average transmit power and maximum transmit power at the BS. The proposed scheme significantly outperforms "state of the art" schemes that employ only the optimal time allocation. If a single EH transmitter is considered, we generalize the optimal solutions for the case of fixed circuit power consumption, which refers to a much more practical scenario.

  3. An Advanced Temporal Credential-Based Security Scheme with Mutual Authentication and Key Agreement for Wireless Sensor Networks

    PubMed Central

    Li, Chun-Ta; Weng, Chi-Yao; Lee, Cheng-Chi

    2013-01-01

    Wireless sensor networks (WSNs) can be quickly and randomly deployed in any harsh and unattended environment and only authorized users are allowed to access reliable sensor nodes in WSNs with the aid of gateways (GWNs). Secure authentication models among the users, the sensor nodes and GWN are important research issues for ensuring communication security and data privacy in WSNs. In 2013, Xue et al. proposed a temporal-credential-based mutual authentication and key agreement scheme for WSNs. However, in this paper, we point out that Xue et al.'s scheme cannot resist stolen-verifier, insider, off-line password guessing, smart card lost problem and many logged-in users' attacks and these security weaknesses make the scheme inapplicable to practical WSN applications. To tackle these problems, we suggest a simple countermeasure to prevent proposed attacks while the other merits of Xue et al.'s authentication scheme are left unchanged. PMID:23887085

  4. An advanced temporal credential-based security scheme with mutual authentication and key agreement for wireless sensor networks.

    PubMed

    Li, Chun-Ta; Weng, Chi-Yao; Lee, Cheng-Chi

    2013-01-01

    Wireless sensor networks (WSNs) can be quickly and randomly deployed in any harsh and unattended environment and only authorized users are allowed to access reliable sensor nodes in WSNs with the aid of gateways (GWNs). Secure authentication models among the users, the sensor nodes and GWN are important research issues for ensuring communication security and data privacy in WSNs. In 2013, Xue et al. proposed a temporal-credential-based mutual authentication and key agreement scheme for WSNs. However, in this paper, we point out that Xue et al.'s scheme cannot resist stolen-verifier, insider, off-line password guessing, smart card lost problem and many logged-in users' attacks and these security weaknesses make the scheme inapplicable to practical WSN applications. To tackle these problems, we suggest a simple countermeasure to prevent proposed attacks while the other merits of Xue et al.'s authentication scheme are left unchanged. PMID:23887085

  5. Health worker preferences for performance-based payment schemes in a rural health district in Burkina Faso

    PubMed Central

    Yé, Maurice; Diboulo, Eric; Kagoné, Moubassira; Sié, Ali; Sauerborn, Rainer; Loukanova, Svetla

    2016-01-01

    Background One promising way to improve the motivation of healthcare providers and the quality of healthcare services is performance-based incentives (PBIs) also referred as performance-based financing. Our study aims to explore healthcare providers’ preferences for an incentive scheme based on local resources, which aimed at improving the quality of maternal and child health care in the Nouna Health District. Design A qualitative and quantitative survey was carried out in 2010 involving 94 healthcare providers within 34 health facilities. In addition, in-depth interviews involving a total of 33 key informants were conducted at health facility levels. Results Overall, 85% of health workers were in favour of an incentive scheme based on the health district's own financial resources (95% CI: [71.91; 88.08]). Most health workers (95 and 96%) expressed a preference for financial incentives (95% CI: [66.64; 85.36]) and team-based incentives (95% CI: [67.78; 86.22]), respectively. The suggested performance indicators were those linked to antenatal care services, prevention of mother-to-child human immunodeficiency virus transmission, neonatal care, and immunization. Conclusions The early involvement of health workers and other stakeholders in designing an incentive scheme proved to be valuable. It ensured their effective participation in the process and overall acceptance of the scheme at the end. This study is an important contribution towards the designing of effective PBI schemes. PMID:26739784

  6. A Hybrid ARQ Scheme Based on Rate-Compatible Low-Density Parity-Check Codes by Shortening and Extending

    NASA Astrophysics Data System (ADS)

    Okamura, Toshihiko

    Incremental Redundancy Hybrid ARQ (IR-HARQ) based on rate-compatible punctured low-density parity-check (LDPC) codes can achieve high throughput over a wide range of SNRs. One drawback of such IR-HARQ schemes is high computational complexity of decoding for early transmission at high rates. In order to overcome this problem, a HARQ scheme based on rate-compatible LDPC codes by shortening and extending is presented in this paper. In the HARQ scheme, a high-rate mother code is transmitted at first, and parity-bits of a shortened code are transmitted for early retransmission requests. With a low-complexity decoder of the high-rate mother code, this shortened-code approach would result in low computational complexity of decoding, but it causes smaller length and larger number of shortened codes to be decoded as retransmission repeats. To prevent the resultant degradation of performance and complexity, extending is efficiently applied to the shortened codes after predetermined retransmission-times. A multi-edge type code-design is employed to construct irregular LDPC codes that meet the requirement of the HARQ scheme. Simulation results show that the HARQ scheme can achieve lower computational complexity of decoding than a conventional IR-HARQ scheme with good throughput over a wide range of SNRs.

  7. FCMAC-Yager: a novel Yager-inference-scheme-based fuzzy CMAC.

    PubMed

    Sim, J; Tung, W L; Quek, Chai

    2006-11-01

    The cerebellum is a brain region important for a number of motor and cognitive functions. It is able to generate error correction signals to drive learning and for the acquisition of memory skills. The cerebellar model articulation controller (CMAC) is a neural network inspired by the neurophysiologic theory of the cerebellum and is recognized for its localized generalization and rapid algorithmic computation capabilities. The main deficiencies in the basic CMAC structure are: (1) it is difficult to interpret the internal operations of the CMAC network and (2) the resolution (quantization) problem arising from the partitioning of the input training space. These limitations lead to the synthesis of a fuzzy quantization technique and the mapping of a fuzzy inference scheme onto the CMAC structure. The discrete incremental clustering (DIC) technique is employed to alleviate the quantization problem in the CMAC structure, resulting in the fuzzy CMAC (FCMAC) network. The Yager inference scheme (Yager), which possesses firm fuzzy logic foundation and maps closely to the logical implication operations in the classical (binary) logic framework, is subsequently mapped onto the FCMAC structure. This results in a novel fuzzy neural architecture known as thefuzzy cerebellar model articulation controller-Yager (FCMAC-Yager) system. The proposed FCMAC-Yager network exhibits learning and memory capabilities of the cerebellum through the CMAC structure while emulating the human way of reasoning through the Yager. The new FCMAC-Yager network employs a two-phase training algorithm consisting of structural learning based on the DIC technique and parameter learning using hebbian learning (associative long-term potentiation). The proposed FCMAC-Yager architecture is evaluated using an extensive suite of real-life applications such as highway traffic-trend modeling and prediction and performing as an early warning system for bank failure classification and medical diagnosis of breast

  8. Noise Robust Feature Scheme for Automatic Speech Recognition Based on Auditory Perceptual Mechanisms

    NASA Astrophysics Data System (ADS)

    Cai, Shang; Xiao, Yeming; Pan, Jielin; Zhao, Qingwei; Yan, Yonghong

    Mel Frequency Cepstral Coefficients (MFCC) are the most popular acoustic features used in automatic speech recognition (ASR), mainly because the coefficients capture the most useful information of the speech and fit well with the assumptions used in hidden Markov models. As is well known, MFCCs already employ several principles which have known counterparts in the peripheral properties of human hearing: decoupling across frequency, mel-warping of the frequency axis, log-compression of energy, etc. It is natural to introduce more mechanisms in the auditory periphery to improve the noise robustness of MFCC. In this paper, a k-nearest neighbors based frequency masking filter is proposed to reduce the audibility of spectra valleys which are sensitive to noise. Besides, Moore and Glasberg's critical band equivalent rectangular bandwidth (ERB) expression is utilized to determine the filter bandwidth. Furthermore, a new bandpass infinite impulse response (IIR) filter is proposed to imitate the temporal masking phenomenon of the human auditory system. These three auditory perceptual mechanisms are combined with the standard MFCC algorithm in order to investigate their effects on ASR performance, and a revised MFCC extraction scheme is presented. Recognition performances with the standard MFCC, RASTA perceptual linear prediction (RASTA-PLP) and the proposed feature extraction scheme are evaluated on a medium-vocabulary isolated-word recognition task and a more complex large vocabulary continuous speech recognition (LVCSR) task. Experimental results show that consistent robustness against background noise is achieved on these two tasks, and the proposed method outperforms both the standard MFCC and RASTA-PLP.

  9. A copyright protection scheme for digital images based on shuffled singular value decomposition and visual cryptography.

    PubMed

    Devi, B Pushpa; Singh, Kh Manglem; Roy, Sudipta

    2016-01-01

    This paper proposes a new watermarking algorithm based on the shuffled singular value decomposition and the visual cryptography for copyright protection of digital images. It generates the ownership and identification shares of the image based on visual cryptography. It decomposes the image into low and high frequency sub-bands. The low frequency sub-band is further divided into blocks of same size after shuffling it and then the singular value decomposition is applied to each randomly selected block. Shares are generated by comparing one of the elements in the first column of the left orthogonal matrix with its corresponding element in the right orthogonal matrix of the singular value decomposition of the block of the low frequency sub-band. The experimental results show that the proposed scheme clearly verifies the copyright of the digital images, and is robust to withstand several image processing attacks. Comparison with the other related visual cryptography-based algorithms reveals that the proposed method gives better performance. The proposed method is especially resilient against the rotation attack. PMID:27468392

  10. A novel addressing scheme for PMIPv6 based global IP-WSNs.

    PubMed

    Islam, Md Motaharul; Huh, Eui-Nam

    2011-01-01

    IP based Wireless Sensor Networks (IP-WSNs) are being used in healthcare, home automation, industrial control and agricultural monitoring. In most of these applications global addressing of individual IP-WSN nodes and layer-three routing for mobility enabled IP-WSN with special attention to reliability, energy efficiency and end to end delay minimization are a few of the major issues to be addressed. Most of the routing protocols in WSN are based on layer-two approaches. For reliability and end to end communication enhancement the necessity of layer-three routing for IP-WSNs is generating significant attention among the research community, but due to the hurdle of maintaining routing state and other communication overhead, it was not possible to introduce a layer-three routing protocol for IP-WSNs. To address this issue we propose in this paper a global addressing scheme and layer-three based hierarchical routing protocol. The proposed addressing and routing approach focuses on all the above mentioned issues. Simulation results show that the proposed addressing and routing approach significantly enhances the reliability, energy efficiency and end to end delay minimization. We also present architecture, message formats and different routing scenarios in this paper. PMID:22164084

  11. Estimation of Missing Precipitation Records using Classifier, Cluster and Proximity Metric-Based Interpolation Schemes

    NASA Astrophysics Data System (ADS)

    Teegavarapu, R. S.

    2012-12-01

    New optimal proximity-based imputation, k-nn (k-nearest neighbor) classification and k-means clustering methods are proposed and developed for estimation of missing precipitation records in this study. Variants of these methods are embedded in optimization formulations to optimize the weighing schemes involving proximity measures. Ten different binary and real valued distance metrics are used as proximity measures. Two climatic regions, Kentucky and Florida, (temperate and tropical) in the United States, with different gauge density and gauge network structure are used as case studies to evaluate the efficacy of these methods for estimation of missing precipitation data. A comprehensive exercise is undertaken in this study to compare the performances of the developed new methods and their variants to those of already available methods in literature. Several deterministic and stochastic spatial interpolation methods and their improvised variants using optimization formulations are used for comparisons. Results from these comparisons indicate that the optimal proximity-based imputation, k-mean cluster-based and k-nn classification methods are competitive when combined with mathematical programming formulations and provided better estimates of missing precipitation data than available deterministic and stochastic interpolation methods.

  12. Infrared and visible image fusion scheme based on NSCT and low-level visual features

    NASA Astrophysics Data System (ADS)

    Li, Huafeng; Qiu, Hongmei; Yu, Zhengtao; Zhang, Yafei

    2016-05-01

    Multi-scale transform (MST) is an efficient tool for image fusion. Recently, many fusion methods have been developed based on different MSTs, and they have shown potential application in many fields. In this paper, we propose an effective infrared and visible image fusion scheme in nonsubsampled contourlet transform (NSCT) domain, in which the NSCT is firstly employed to decompose each of the source images into a series of high frequency subbands and one low frequency subband. To improve the fusion performance we designed two new activity measures for fusion of the lowpass subbands and the highpass subbands. These measures are developed based on the fact that the human visual system (HVS) percept the image quality mainly according to its some low-level features. Then, the selection principles of different subbands are presented based on the corresponding activity measures. Finally, the merged subbands are constructed according to the selection principles, and the final fused image is produced by applying the inverse NSCT on these merged subbands. Experimental results demonstrate the effectiveness and superiority of the proposed method over the state-of-the-art fusion methods in terms of both visual effect and objective evaluation results.

  13. New calculation schemes for the {open_quotes}building-base{close_quotes} system in conditions of collapsing loess soils

    SciTech Connect

    Mezherovskii, V.A.

    1994-05-01

    New calculation schemes are suggested for the {open_quotes}building-loess collapsing base{close_quotes} system, with the help of which it is possible to obtain values of the forces and movements occurring in a building as a result of collapses of bases that are close to the real ones in the nature of moistening and deformations of loess strata.

  14. Competitive allocation of resources on a network: an agent-based model of air companies competing for the best routes

    NASA Astrophysics Data System (ADS)

    Gurtner, Gérald; Valori, Luca; Lillo, Fabrizio

    2015-05-01

    We present a stylized model of the allocation of resources on a network. By considering as a concrete example the network of sectors of the airspace, where each node is a sector characterized by a maximal number of simultaneously present aircraft, we consider the problem of air companies competing for the allocation of the airspace. Each company is characterized by a cost function, weighting differently punctuality and length of the flight. We consider the model in the presence of pure and mixed populations of types of airline companies and we study how the equilibria depends on the characteristics of the network.

  15. An Anti-Cheating Visual Cryptography Scheme Based on Chaotic Encryption System

    NASA Astrophysics Data System (ADS)

    Han, Yanyan; Xu, Zhuolin; Ge, Xiaonan; He, Wencai

    By chaotic encryption system and introducing the trusted third party (TTP), in this paper, an anti-cheating visual cryptography scheme (VCS) is proposed. The scheme solved the problem of dishonest participants and improved the security of chaotic encryption system. Simulation results and analysis show that the recovery image is acceptable, the system can detect the cheating in participants effectively and with high security.

  16. Multimode interference coupler based photonic analog-to-digital conversion scheme.

    PubMed

    Shile, Wei; Jian, Wu; Lingjuan, Zhao; Chen, Yao; Chen, Ji; Dan, Lu; Xilin, Zhang; Zuoshan, Yin

    2012-09-01

    A novel phase-shifted optical quantization scheme for an all-optical analog-to-digital converter, which uses 4×4 multimode interference couplers, is demonstrated and theoretically analyzed. The whole scheme can be integrated on a chip. PMID:22940995

  17. Development of a web GIS application for emissions inventory spatial allocation based on open source software tools

    NASA Astrophysics Data System (ADS)

    Gkatzoflias, Dimitrios; Mellios, Giorgos; Samaras, Zissis

    2013-03-01

    Combining emission inventory methods and geographic information systems (GIS) remains a key issue for environmental modelling and management purposes. This paper examines the development of a web GIS application as part of an emission inventory system that produces maps and files with spatial allocated emissions in a grid format. The study is not confined in the maps produced but also presents the features and capabilities of a web application that can be used by every user even without any prior knowledge of the GIS field. The development of the application was based on open source software tools such as MapServer for the GIS functions, PostgreSQL and PostGIS for the data management and HTML, PHP and JavaScript as programming languages. In addition, background processes are used in an innovative manner to handle the time consuming and computational costly procedures of the application. Furthermore, a web map service was created to provide maps to other clients such as the Google Maps API v3 that is used as part of the user interface. The output of the application includes maps in vector and raster format, maps with temporal resolution on daily and hourly basis, grid files that can be used by air quality management systems and grid files consistent with the European Monitoring and Evaluation Programme Grid. Although the system was developed and validated for the Republic of Cyprus covering a remarkable wide range of pollutant and emissions sources, it can be easily customized for use in other countries or smaller areas, as long as geospatial and activity data are available.

  18. Comparison of accelerator-based with reactor-based waste transmutation schemes

    SciTech Connect

    Sailor, W.C.; Beard, C.A.; Venneri, F.; Davidson, J.W.

    1993-12-01

    Accelerator-based transmutation of waste (ATW) systems for the destruction of commercial LWR spent fuel are compared with systems based on thermal reactors accomplish the same objectives. When the same technology is assumed for the actinide-burning aspect of the two systems, it is seen that the size of the accelerator is determined only by the choice of how many of the long-lived fission products to burn. if none are transmuted, then the accelerator is not necessary. This result is independent of the choice of fluid carrier, and whether the actinides are destroyed in an ATW system or in a separate reactor.

  19. Dynamic Resource Allocation in Hybrid Access Femtocell Network

    PubMed Central

    Islam, Mohammad Tariqul

    2014-01-01

    Intercell interference is one of the most challenging issues in femtocell deployment under the coverage of existing macrocell. Allocation of resources between femtocell and macrocell is essential to counter the effects of interference in dense femtocell networks. Advances in resource management strategies have improved the control mechanism for interference reduction at lower node density, but most of them are ineffective at higher node density. In this paper, a dynamic resource allocation management algorithm (DRAMA) for spectrum shared hybrid access OFDMA femtocell network is proposed. To reduce the macro-femto-tier interference and to improve the quality of service, the proposed algorithm features a dynamic resource allocation scheme by controlling them both centrally and locally. The proposed scheme focuses on Femtocell Access Point (FAP) owners' satisfaction and allows maximum utilization of available resources based on congestion in the network. A simulation environment is developed to study the quantitative performance of DRAMA in hybrid access-control femtocell network and compare it to closed and open access mechanisms. The performance analysis shows that higher number of random users gets connected to the FAP without compromising FAP owners' satisfaction allowing the macrocell to offload a large number of users in a dense heterogeneous network. PMID:24782662

  20. Dynamic resource allocation in hybrid access femtocell network.

    PubMed

    Ahmed, Afaz Uddin; Islam, Mohammad Tariqul; Ismail, Mahamod; Ghanbarisabagh, Mohammad

    2014-01-01

    Intercell interference is one of the most challenging issues in femtocell deployment under the coverage of existing macrocell. Allocation of resources between femtocell and macrocell is essential to counter the effects of interference in dense femtocell networks. Advances in resource management strategies have improved the control mechanism for interference reduction at lower node density, but most of them are ineffective at higher node density. In this paper, a dynamic resource allocation management algorithm (DRAMA) for spectrum shared hybrid access OFDMA femtocell network is proposed. To reduce the macro-femto-tier interference and to improve the quality of service, the proposed algorithm features a dynamic resource allocation scheme by controlling them both centrally and locally. The proposed scheme focuses on Femtocell Access Point (FAP) owners' satisfaction and allows maximum utilization of available resources based on congestion in the network. A simulation environment is developed to study the quantitative performance of DRAMA in hybrid access-control femtocell network and compare it to closed and open access mechanisms. The performance analysis shows that higher number of random users gets connected to the FAP without compromising FAP owners' satisfaction allowing the macrocell to offload a large number of users in a dense heterogeneous network. PMID:24782662

  1. An improved parameter estimation scheme for image modification detection based on DCT coefficient analysis.

    PubMed

    Yu, Liyang; Han, Qi; Niu, Xiamu; Yiu, S M; Fang, Junbin; Zhang, Ye

    2016-02-01

    Most of the existing image modification detection methods which are based on DCT coefficient analysis model the distribution of DCT coefficients as a mixture of a modified and an unchanged component. To separate the two components, two parameters, which are the primary quantization step, Q1, and the portion of the modified region, α, have to be estimated, and more accurate estimations of α and Q1 lead to better detection and localization results. Existing methods estimate α and Q1 in a completely blind manner, without considering the characteristics of the mixture model and the constraints to which α should conform. In this paper, we propose a more effective scheme for estimating α and Q1, based on the observations that, the curves on the surface of the likelihood function corresponding to the mixture model is largely smooth, and α can take values only in a discrete set. We conduct extensive experiments to evaluate the proposed method, and the experimental results confirm the efficacy of our method. PMID:26804669

  2. Mode-shape-based mass detection scheme using mechanically diverse, indirectly coupled microresonator arrays

    NASA Astrophysics Data System (ADS)

    Glean, Aldo A.; Judge, John A.; Vignola, Joseph F.; Ryan, Teresa J.

    2015-02-01

    We explore vibration localization in arrays of microresonators used for ultrasensitive mass detection and describe an algorithm for identifying the location and amount of added mass using measurements of a vibration mode of the system. For a set of sensing elements coupled through a common shuttle mass, the inter-element coupling is shown to be proportional to the ratio of the element masses to the shuttle mass and to vary with the frequency mistuning between any two sensing elements. When any two elements have sufficiently similar frequencies, mass adsorption on one element can result in measurable changes to multiple modes of the system. We describe the effects on system frequencies and mode shapes due to added mass, in terms of mass ratio and frequency spacing. In cases in which modes are not fully localized, frequency-shift-based mass detection methods may give ambiguous results. The mode-shape-based detection algorithm presented uses a single measured mode shape and corresponding natural frequency to identify the location and amount of added mass. Mass detection in the presence of measurement noise is numerically simulated using a ten element sensor array. The accuracy of the detection scheme is shown to depend on the amplitude with which each element vibrates in the chosen mode.

  3. Motion control of nonlinear gantry crane system via priority-based fitness scheme in firefly algorithm

    NASA Astrophysics Data System (ADS)

    Jaafar, Hazriq Izzuan; Latif, Norfaneysa Abd; Kassim, Anuar Mohamed; Abidin, Amar Faiz Zainal; Hussien, Sharifah Yuslinda Syed; Aras, Mohd Shahrieel Mohd

    2015-05-01

    Advanced manufacturing technology made Gantry Crane System (GCS) is one of the suitable heavy machinery transporters and frequently employed in handling with huge materials. The interconnection of trolley movement and payload oscillation has a technical impact which needs to be considered. Once the trolley moves to the desired position with high speed, this will induce undesirable's payload oscillation. This frequent unavoidable load swing causes an efficiency drop, load damages and even accidents. In this paper, a new control strategy of Firefly Algorithm (FA) will be developed to obtain five optimal controller parameters (PID and PD) via Priority-based Fitness Scheme (PFS). Combinations of these five parameters are utilized for controlling trolley movement and minimizing the angle of payload oscillation. This PFS is prioritized based on steady-state error (SSE), overshoot (OS) and settling time (Ts) according to the needs and circumstances. Lagrange equation will be chosen for modeling and simulation will be conducted by using related software. Simulation results show that the proposed control strategy is efficient to control the trolley movement to the desired position and minimize the angle of payload oscillation.

  4. A cloud-based forensics tracking scheme for online social network clients.

    PubMed

    Lin, Feng-Yu; Huang, Chien-Cheng; Chang, Pei-Ying

    2015-10-01

    In recent years, with significant changes in the communication modes, most users are diverted to cloud-based applications, especially online social networks (OSNs), which applications are mostly hosted on the outside and available to criminals, enabling them to impede criminal investigations and intelligence gathering. In the virtual world, how the Law Enforcement Agency (LEA) identifies the "actual" identity of criminal suspects, and their geolocation in social networks, is a major challenge to current digital investigation. In view of this, this paper proposes a scheme, based on the concepts of IP location and network forensics, which aims to develop forensics tracking on OSNs. According to our empirical analysis, the proposed mechanism can instantly trace the "physical location" of a targeted service resource identifier (SRI), when the target client is using online social network applications (Facebook, Twitter, etc.), and can analyze the probable target client "identity" associatively. To the best of our knowledge, this is the first individualized location method and architecture developed and evaluated in OSNs. PMID:26341157

  5. Structure-Based Consensus Scoring Scheme for Selecting Class A Aminergic GPCR Fragments.

    PubMed

    Kelemen, Ádám A; Kiss, Róbert; Ferenczy, György G; Kovács, László; Flachner, Beáta; Lőrincz, Zsolt; Keserű, György M

    2016-02-22

    Aminergic G-protein coupled receptors (GPRCs) represent well-known targets of central nervous-system related diseases. In this study a structure-based consensus virtual screening scheme was developed for designing targeted fragment libraries against class A aminergic GPCRs. Nine representative aminergic GPCR structures were selected by first clustering available X-ray structures and then choosing the one in each cluster that performs best in self-docking calculations. A consensus scoring protocol was developed using known promiscuous aminergic ligands and decoys as a training set. The consensus score (FrACS-fragment aminergic consensus score) calculated for the optimized protein ensemble showed improved enrichments in most cases as compared to stand-alone structures. Retrospective validation was carried out on public screening data for aminergic targets (5-HT1 serotonin receptor, TA1 trace-amine receptor) showing 8-17-fold enrichments using an ensemble of aminergic receptor structures. The performance of the structure based FrACS in combination with our ligand-based prefilter (FrAGS) was investigated both in a retrospective validation on the ChEMBL database and in a prospective validation on an in-house fragment library. In prospective validation virtual fragment hits were tested on 5-HT6 serotonin receptors not involved in the development of FrACS. Six out of the 36 experimentally tested fragments exhibited remarkable antagonist efficacies, and 4 showed IC50 values in the low micromolar or submicromolar range in a cell-based assay. Both retrospective and prospective validations revealed that the methodology is suitable for designing focused class A GPCR fragment libraries from large screening decks, commercial compound collections, or virtual databases. PMID:26760056

  6. Solute based Lagrangian scheme in modeling the drying process of soft matter solutions.

    PubMed

    Meng, Fanlong; Luo, Ling; Doi, Masao; Ouyang, Zhongcan

    2016-02-01

    We develop a new dynamical model to study the drying process of a droplet of soft matter solutions. The model includes the processes of solute diffusion, gel-layer formation and cavity creation. A new scheme is proposed to handle the diffusion dynamics taking place in such processes. In this scheme, the dynamics is described by the motion of material points taken on solute. It is convenient to apply this scheme to solve problems that involve moving boundaries and phase changes. As an example, we show results of a numerical calculation for a drying spherical droplet, and discuss how initial concentration and evaporation rate affect the structural evolution of the droplet. PMID:26920525

  7. A Computerized English-Spanish Correlation Index to Five Biomedical Library Classification Schemes Based on MeSH*

    PubMed Central

    Muench, Eugene V.

    1971-01-01

    A computerized English/Spanish correlation index to five biomedical library classification schemes and a computerized English/Spanish, Spanish/English listings of MeSH are described. The index was accomplished by supplying appropriate classification numbers of five classification schemes (National Library of Medicine; Library of Congress; Dewey Decimal; Cunningham; Boston Medical) to MeSH and a Spanish translation of MeSH The data were keypunched, merged on magnetic tape, and sorted in a computer alphabetically by English and Spanish subject headings and sequentially by classification number. Some benefits and uses of the index are: a complete index to classification schemes based on MeSH terms; a tool for conversion of classification numbers when reclassifying collections; a Spanish index and a crude Spanish translation of five classification schemes; a data base for future applications, e.g., automatic classification. Other classification schemes, such as the UDC, and translations of MeSH into other languages can be added. PMID:5172471

  8. Comparison of the co-gasification of sewage sludge and food wastes and cost-benefit analysis of gasification- and incineration-based waste treatment schemes.

    PubMed

    You, Siming; Wang, Wei; Dai, Yanjun; Tong, Yen Wah; Wang, Chi-Hwa

    2016-10-01

    The compositions of food wastes and their co-gasification producer gas were compared with the existing data of sewage sludge. Results showed that food wastes are more favorable than sewage sludge for co-gasification based on residue generation and energy output. Two decentralized gasification-based schemes were proposed to dispose of the sewage sludge and food wastes in Singapore. Monte Carlo simulation-based cost-benefit analysis was conducted to compare the proposed schemes with the existing incineration-based scheme. It was found that the gasification-based schemes are financially superior to the incineration-based scheme based on the data of net present value (NPV), benefit-cost ratio (BCR), and internal rate of return (IRR). Sensitivity analysis was conducted to suggest effective measures to improve the economics of the schemes. PMID:27416510

  9. Adaptively Refined Euler and Navier-Stokes Solutions with a Cartesian-Cell Based Scheme

    NASA Technical Reports Server (NTRS)

    Coirier, William J.; Powell, Kenneth G.

    1995-01-01

    A Cartesian-cell based scheme with adaptive mesh refinement for solving the Euler and Navier-Stokes equations in two dimensions has been developed and tested. Grids about geometrically complicated bodies were generated automatically, by recursive subdivision of a single Cartesian cell encompassing the entire flow domain. Where the resulting cells intersect bodies, N-sided 'cut' cells were created using polygon-clipping algorithms. The grid was stored in a binary-tree data structure which provided a natural means of obtaining cell-to-cell connectivity and of carrying out solution-adaptive mesh refinement. The Euler and Navier-Stokes equations were solved on the resulting grids using an upwind, finite-volume formulation. The inviscid fluxes were found in an upwinded manner using a linear reconstruction of the cell primitives, providing the input states to an approximate Riemann solver. The viscous fluxes were formed using a Green-Gauss type of reconstruction upon a co-volume surrounding the cell interface. Data at the vertices of this co-volume were found in a linearly K-exact manner, which ensured linear K-exactness of the gradients. Adaptively-refined solutions for the inviscid flow about a four-element airfoil (test case 3) were compared to theory. Laminar, adaptively-refined solutions were compared to accepted computational, experimental and theoretical results.

  10. Numerical investigation of complex flooding schemes for surfactant polymer based enhanced oil recovery

    NASA Astrophysics Data System (ADS)

    Dutta, Sourav; Daripa, Prabir

    2015-11-01

    Surfactant-polymer flooding is a widely used method of chemical enhanced oil recovery (EOR) in which an array of complex fluids containing suitable and varying amounts of surfactant or polymer or both mixed with water is injected into the reservoir. This is an example of multiphase, multicomponent and multiphysics porous media flow which is characterized by the spontaneous formation of complex viscous fingering patterns and is modeled by a system of strongly coupled nonlinear partial differential equations with appropriate initial and boundary conditions. Here we propose and discuss a modern, hybrid method based on a combination of a discontinuous, multiscale finite element formulation and the method of characteristics to accurately solve the system. Several types of flooding schemes and rheological properties of the injected fluids are used to numerically study the effectiveness of various injection policies in minimizing the viscous fingering and maximizing oil recovery. Numerical simulations are also performed to investigate the effect of various other physical and model parameters such as heterogeneity, relative permeability and residual saturation on the quantities of interest like cumulative oil recovery, sweep efficiency, fingering intensity to name a few. Supported by the grant NPRP 08-777-1-141 from the Qatar National Research Fund (a member of The Qatar Foundation).

  11. 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.

  12. An Improved EKG-Based Key Agreement Scheme for Body Area Networks

    NASA Astrophysics Data System (ADS)

    Ali, Aftab; Khan, Farrukh Aslam

    Body area networks (BANs) play an important role in mobile health monitoring such as, monitoring the health of patients in a hospital or physical status of soldiers in a battlefield. By securing the BAN, we actually secure the lives of soldiers or patients. This work presents an electrocardiogram (EKG) based key agreement scheme using discrete wavelet transform (DWT) for the sake of generating a common key in a body area network. The use of EKG brings plug-and-play capability in BANs; i.e., the sensors are just placed on the human body and a secure communication is started among these sensors. The process is made secure by using the iris or fingerprints to lock and then unlock the blocks during exchange between the communicating sensors. The locking and unlocking is done through watermarking. When a watermark is added at the sender side, the block is locked and when it is removed at the receiver side, the block is unlocked. By using iris or fingerprints, the security of the technique improves and its plug-and-play capability is not affected. The analysis is done by using real 2-lead EKG data sampled at a rate of 125 Hz taken from MIT PhysioBank database.

  13. K-Optimal Gradient Encoding Scheme for Fourth-Order Tensor-Based Diffusion Profile Imaging

    PubMed Central

    Alipoor, Mohammad; Gu, Irene Yu-Hua; Mehnert, Andrew; Maier, Stephan E.; Starck, Göran

    2015-01-01

    The design of an optimal gradient encoding scheme (GES) is a fundamental problem in diffusion MRI. It is well studied for the case of second-order tensor imaging (Gaussian diffusion). However, it has not been investigated for the wide range of non-Gaussian diffusion models. The optimal GES is the one that minimizes the variance of the estimated parameters. Such a GES can be realized by minimizing the condition number of the design matrix (K-optimal design). In this paper, we propose a new approach to solve the K-optimal GES design problem for fourth-order tensor-based diffusion profile imaging. The problem is a nonconvex experiment design problem. Using convex relaxation, we reformulate it as a tractable semidefinite programming problem. Solving this problem leads to several theoretical properties of K-optimal design: (i) the odd moments of the K-optimal design must be zero; (ii) the even moments of the K-optimal design are proportional to the total number of measurements; (iii) the K-optimal design is not unique, in general; and (iv) the proposed method can be used to compute the K-optimal design for an arbitrary number of measurements. Our Monte Carlo simulations support the theoretical results and show that, in comparison with existing designs, the K-optimal design leads to the minimum signal deviation. PMID:26451376

  14. High-order central Hermite WENO schemes: Dimension-by-dimension moment-based reconstructions

    NASA Astrophysics Data System (ADS)

    Tao, Zhanjing; Li, Fengyan; Qiu, Jianxian

    2016-08-01

    In this paper, a class of high-order central finite volume schemes is proposed for solving one- and two-dimensional hyperbolic conservation laws. Formulated on staggered meshes, the methods involve Hermite WENO (HWENO) spatial reconstructions, and Lax-Wendroff type discretizations or the natural continuous extension of Runge-Kutta methods in time. Differently from the central Hermite WENO methods we developed previously in Tao et al. (2015) [34], the spatial reconstructions, a core ingredient of the methods, are based on the zeroth-order and the first-order moments of the solution, and are implemented through a dimension-by-dimension strategy when the spatial dimension is higher than one. This leads to much simpler implementation of the methods in higher dimension and better cost efficiency. Meanwhile, the proposed methods have the attractive features of the general central Hermite WENO methods such as being compact in reconstruction and requiring neither flux splitting nor numerical fluxes, while being accurate and essentially non-oscillatory. A collection of one- and two-dimensional numerical examples is presented to demonstrate high resolution and robustness of the methods in capturing smooth and non-smooth solutions.

  15. Tuning of a convective gravity wave source scheme based on HIRDLS observations

    NASA Astrophysics Data System (ADS)

    Trinh, Q. T.; Kalisch, S.; Preusse, P.; Ern, M.; Chun, H.-Y.; Eckermann, S. D.; Kang, M.-J.; Riese, M.

    2015-12-01

    Convection as one dominant source of atmospheric gravity waves (GWs) has been in focus of investigation over recent years. However, its spatial and temporal forcing scales are not well known. In this work we address this open issue by a systematic verification of free parameters of the Yonsei convective GW source scheme based on observations from the High Resolution Dynamics Limb Sounder (HIRDLS). Observational constraints are taken into account by applying a comprehensive observational filter on the simulated GWs. By this approach, only long horizontal scale convective GWs are addressed. Results show that effects of long horizontal scale convective GWs can be successfully simulated by the superposition of three or four combinations of parameter sets reproducing the observed GW spectrum. These selected parameter sets are different for northern and southern summer. Although long horizontal scale waves are only part of the full spectrum of convective GWs, the momentum flux of these waves are found to be significant and relevant for the driving of the QBO. The zonal momentum balance is considered in vertical cross sections of GW momentum flux (GWMF) and GW drag (GWD). Global maps of the horizontal distribution of GWMF are considered and consistency between simulated results and HIRDLS observations is found. The latitude dependence of the zonal phase speed spectrum of GWMF and its change with altitude is discussed.

  16. Kinematics and force analysis of a robot hand based on an artificial biological control scheme

    NASA Astrophysics Data System (ADS)

    Kim, Man Guen

    An artificial biological control scheme (ABCS) is used to study the kinematics and statics of a multifingered hand with a view to developing an efficient control scheme for grasping. The ABCS is based on observation of human grasping, intuitively taking it as the optimum model for robotic grasping. A final chapter proposes several grasping measures to be applied to the design and control of a robot hand. The ABCS leads to the definition of two modes of the grasping action: natural grasping (NG), which is the human motion to grasp the object without any special task command, and forced grasping (FG), which is the motion with a specific task. The grasping direction line (GDL) is defined to determine the position and orientation of the object in the hand. The kinematic model of a redundant robot arm and hand is developed by reconstructing the human upper extremity and using anthropometric measurement data. The inverse kinematic analyses of various types of precision and power grasping are studied by replacing the three-link with one virtual link and using the GDL. The static force analysis for grasping with fingertips is studied by applying the ABCS. A measure of grasping stability, that maintains the positions of contacts as well as the configurations of the redundant fingers, is derived. The grasping stability measure (GSM), a measure of how well the hand maintains grasping under the existence of external disturbance, is derived by the torque vector of the hand calculated from the external force applied to the object. The grasping manipulability measure (GMM), a measure of how well the hand manipulates the object for the task, is derived by the joint velocity vector of the hand calculated from the object velocity. The grasping performance measure (GPM) is defined by the sum of the directional components of the GSM and the GMM. Finally, a planar redundant hand with two fingers is examined in order to study the various postures of the hand performing pinch grasping by

  17. Data Division Scheme Based on Homomorphic Encryption in WSNs for Health Care.

    PubMed

    Wang, Xiaoni; Zhang, Zhenjiang

    2015-12-01

    The use of wireless sensor networks for wearable computing in health care is growing quickly. Numerous applications are already in use, such as blood pressure monitors and heart rate monitors. As such, it is very important for system designers to consider how to protect patient privacy, especially in wireless sensor networks. After studying and analyzing the features of wireless sensor networks in medical systems, a data division scheme was proposed in this paper, provided the advantages of homomorphic encryption. In the proposed scheme, even if a forwarding node is compromised, the attacker will not be able to eavesdrop on the data, resulting in much stronger privacy than existing schemes. Experimental results shows that the scheme provides a good trade off in resources consumed and system security, and is efficient for encrypting or decrypting sensitive medical data. PMID:26490146

  18. A color and texture based multi-level fusion scheme for ethnicity identification

    NASA Astrophysics Data System (ADS)

    Du, Hongbo; Salah, Sheerko Hma; Ahmed, Hawkar O.

    2014-05-01

    Ethnicity identification of face images is of interest in many areas of application. Different from face recognition of individuals, ethnicity identification classifies faces according to the common features of a specific ethnic group. This paper presents a multi-level fusion scheme for ethnicity identification that combines texture features of local areas of a face using local binary patterns with color features using HSV binning. The scheme fuses the decisions from a k-nearest neighbor classifier and a support vector machine classifier into a final identification decision. We have tested the scheme on a collection of face images from a number of publicly available databases. The results demonstrate the effectiveness of the combined features and improvements on accuracy of identification by the fusion scheme over the identification using individual features and other state-of-art techniques.

  19. A promotion of stability for temporal compression based on SBS in an interferometric scheme

    NASA Astrophysics Data System (ADS)

    Wang, Yulei; Liu, Zhaohong; Yuan, Hang; Bai, Zhenxu; Wang, Hongli; Zhu, Xuehua; Liu, Rui; Li, Sensen; Chen, Yi; Wang, Yirui; Cui, Can; Zhang, Hengkang; He, Weiming; Lu, Zhiwei

    2016-09-01

    An approach that introducing a standing wave into focal area to stabilize the output energy and duration of stimulated Brillouin scattering (SBS) compression is presented. An interferometric scheme filled with FC-770 is used to improve the stability of both output energy and duration two times compared with an equivalent conventional SBS compressor. Moreover, the interferometric scheme shows a promotion for the performance of SBS compression.

  20. A Chaos-based Arbitrated Quantum Signature Scheme in Quantum Crypotosystem

    NASA Astrophysics Data System (ADS)

    Wang, Yijun; Xu, Ke; Guo, Ying

    2014-01-01

    An arbitrated quantum signature (AQS) scheme is demonstrated on a basis of an improved quantum chaotic encryption algorithm using the quantum one-time pad with a chaotic operation string. In this scheme, the signatory signs the message while the receiver verifies the signature's validity with the aid of the trusty arbitrator who plays a crucial role when a possible dispute arises. Analysis shows that the signature can neither be forged nor disavowed by any malicious attackers.

  1. Community-based health insurance programmes and the national health insurance scheme of Nigeria: challenges to uptake and integration

    PubMed Central

    2014-01-01

    Background Nigeria has included a regulated community-based health insurance (CBHI) model within its National Health Insurance Scheme (NHIS). Uptake to date has been disappointing, however. The aim of this study is to review the present status of CBHI in SSA in general to highlight the issues that affect its successful integration within the NHIS of Nigeria and more widely in developing countries. Methods A literature survey using PubMed and EconLit was carried out to identify and review studies that report factors affecting implementation of CBHI in SSA with a focus on Nigeria. Results CBHI schemes with a variety of designs have been introduced across SSA but with generally disappointing results so far. Two exceptions are Ghana and Rwanda, both of which have introduced schemes with effective government control and support coupled with intensive implementation programmes. Poor support for CBHI is repeatedly linked elsewhere with failure to engage and account for the ‘real world’ needs of beneficiaries, lack of clear legislative and regulatory frameworks, inadequate financial support, and unrealistic enrolment requirements. Nigeria’s CBHI-type schemes for the informal sectors of its NHIS have been set up under an appropriate legislative framework, but work is needed to eliminate regressive financing, to involve scheme members in the setting up and management of programmes, to inform and educate more effectively, to eliminate lack of confidence in the schemes, and to address inequity in provision. Targeted subsidies should also be considered. Conclusions Disappointing uptake of CBHI-type NHIS elements in Nigeria can be addressed through closer integration of informal and formal programmes under the NHIS umbrella, with increasing involvement of beneficiaries in scheme design and management, improved communication and education, and targeted financial assistance. PMID:24559409

  2. Equitable utilisation of Indian community based health insurance scheme among its rural membership: cluster randomised controlled trial

    PubMed Central

    Sinha, Tara; Chatterjee, Mirai; Gandhi, Fenil; Jayswal, Rupal; Patel, Falguni; Morris, Saul S; Mills, Anne J

    2007-01-01

    Objective To evaluate alternative strategies for improving the uptake of benefits of a community based health insurance scheme by its poorest members. Design Prospective cluster randomised controlled trial. Setting Self Employed Women's Association (SEWA) community based health insurance scheme in rural India. Participants 713 claimants at baseline (2003) and 1440 claimants two years later among scheme members in 16 rural sub-districts. Interventions After sales service with supportive supervision, prospective reimbursement, both packages, and neither package, randomised by sub-district. Main outcome measures The primary outcome was socioeconomic status of claimants relative to members living in the same sub-district. Secondary outcomes were enrolment rates in SEWA Insurance, mean socioeconomic status of the insured population relative to the general rural population, and rate of claim submission. Results Between 2003 and 2005, the mean socioeconomic status of SEWA Insurance members (relative to the rural population of Gujarat) increased significantly. Rates of claims also increased significantly, on average by 21.6 per 1000 members (P<0.001). However, differences between the intervention groups and the standard scheme were not significant. No systematic effect of time or interventions on the socioeconomic status of claimants relative to members in the same sub-district was found. Conclusions Neither intervention was sufficient to ensure that the poorer members in each sub-district were able to enjoy the greater share of the scheme benefits. Claim submission increased as a result of interventions that seem to have strengthened awareness of and trust in a community based health insurance scheme. Trial registration Clinical trials NCT00421629. PMID:17526594

  3. Optimizing School-Based Health-Promotion Programmes: Lessons from a Qualitative Study of Fluoridated Milk Schemes in the UK

    ERIC Educational Resources Information Center

    Foster, Geraldine R. K.; Tickle, Martin

    2013-01-01

    Background and objective: Some districts in the United Kingdom (UK), where the level of child dental caries is high and water fluoridation has not been possible, implement school-based fluoridated milk (FM) schemes. However, process variables, such as consent to drink FM and loss of children as they mature, impede the effectiveness of these…

  4. A robust and novel dynamic-ID-based authentication scheme for care team collaboration with smart cards.

    PubMed

    Chang, Ya-Fen; Chen, Chia-Chen; Chang, Pei-Yu

    2013-04-01

    Nowadays, users/patients may gain desired medical services on-line because of the rapid development of computer network technologies. Conventional healthcare services are provided by a single server. However, care team collaboration by integrating services is the key to improve financial and clinical performance. How a user/patient accesses desired medical services provided by multiple servers becomes a challenge to realize care team collaboration. User authentication plays an important role to protect resources or services from being accessed by unauthorized users. In this paper, we first discuss the perceived security drawbacks of pervasive smart-card-based remote user authentication schemes. Then, we propose a novel dynamic-ID-based user authentication scheme based on elliptic curve cryptosystem (ECC) for multi-server environment with smart cards. The proposed scheme ensures user anonymity and computational efficiency and complies with essential requirements of a secure smart-card-based authentication scheme for multi-server environment to enable care team collaboration. PMID:23355184

  5. Capsular typing of Streptococcus pneumoniae isolated in an Algerian hospital using a new multiplex PCR-based scheme.

    PubMed

    Ziane, Hanifa; Manageiro, Vera; Ferreira, Eugénia; Bektache, Soumia; Tazir, Mohamed; Caniça, Manuela

    2015-12-01

    We developed a new sequential multiplex-PCR-based typing scheme (MPBTS) for pneumococcal capsular classification. The serogroup/type of 37 control isolates obtained by the Quellung reaction, MPBTS, and nucleotide sequencing, were fully concordant. The serogroups/types of 75 invasive isolates determined by MPBTS, presented 100% specificity and 96% sensitivity, when compared with the Quellung reaction. PMID:26546733

  6. Computer Processor Allocator

    2004-03-01

    The Compute Processor Allocator (CPA) provides an efficient and reliable mechanism for managing and allotting processors in a massively parallel (MP) computer. It maintains information in a database on the health. configuration and allocation of each processor. This persistent information is factored in to each allocation decision. The CPA runs in a distributed fashion to avoid a single point of failure.

  7. WLS-ENO: Weighted-least-squares based essentially non-oscillatory schemes for finite volume methods on unstructured meshes

    NASA Astrophysics Data System (ADS)

    Liu, Hongxu; Jiao, Xiangmin

    2016-06-01

    ENO (Essentially Non-Oscillatory) and WENO (Weighted Essentially Non-Oscillatory) schemes are widely used high-order schemes for solving partial differential equations (PDEs), especially hyperbolic conservation laws with piecewise smooth solutions. For structured meshes, these techniques can achieve high order accuracy for smooth functions while being non-oscillatory near discontinuities. For unstructured meshes, which are needed for complex geometries, similar schemes are required but they are much more challenging. We propose a new family of non-oscillatory schemes, called WLS-ENO, in the context of solving hyperbolic conservation laws using finite-volume methods over unstructured meshes. WLS-ENO is derived based on Taylor series expansion and solved using a weighted least squares formulation. Unlike other non-oscillatory schemes, the WLS-ENO does not require constructing sub-stencils, and hence it provides a more flexible framework and is less sensitive to mesh quality. We present rigorous analysis of the accuracy and stability of WLS-ENO, and present numerical results in 1-D, 2-D, and 3-D for a number of benchmark problems, and also report some comparisons against WENO.

  8. An Adaptive Data Gathering Scheme for Multi-Hop Wireless Sensor Networks Based on Compressed Sensing and Network Coding.

    PubMed

    Yin, Jun; Yang, Yuwang; Wang, Lei

    2016-01-01

    Joint design of compressed sensing (CS) and network coding (NC) has been demonstrated to provide a new data gathering paradigm for multi-hop wireless sensor networks (WSNs). By exploiting the correlation of the network sensed data, a variety of data gathering schemes based on NC and CS (Compressed Data Gathering-CDG) have been proposed. However, these schemes assume that the sparsity of the network sensed data is constant and the value of the sparsity is known before starting each data gathering epoch, thus they ignore the variation of the data observed by the WSNs which are deployed in practical circumstances. In this paper, we present a complete design of the feedback CDG scheme where the sink node adaptively queries those interested nodes to acquire an appropriate number of measurements. The adaptive measurement-formation procedure and its termination rules are proposed and analyzed in detail. Moreover, in order to minimize the number of overall transmissions in the formation procedure of each measurement, we have developed a NP-complete model (Maximum Leaf Nodes Minimum Steiner Nodes-MLMS) and realized a scalable greedy algorithm to solve the problem. Experimental results show that the proposed measurement-formation method outperforms previous schemes, and experiments on both datasets from ocean temperature and practical network deployment also prove the effectiveness of our proposed feedback CDG scheme. PMID:27043574

  9. 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.

  10. A chaotic interleaving scheme for continuous-phase modulation-based orthogonal frequency-division multiplexing systems

    NASA Astrophysics Data System (ADS)

    Hassan, Emad S.; Zhu, Xu; El-Khamy, Said E.; Dessouky, Moawad I.; El-Dolil, Sami A.; Abd El-Samie, Fathi E.

    2013-01-01

    In this article, we propose a chaotic interleaving scheme for continuous-phase modulation-based orthogonal frequency-division multiplexing (CPM-OFDM) systems. The idea of chaotic maps randomisation (CMR) is exploited in this scheme. CMR generates permuted sequences from the sequences to be transmitted with lower correlation among their samples, and hence a better Bit Error Rate (BER) performance can be achieved. The proposed CMR-CPM-OFDM system combines the advantages of frequency diversity and power efficiency from CPM-OFDM and performance improvement from chaotic interleaving. The BER performance of the CPM-OFDM system with and without chaotic interleaving is evaluated by computer simulations. Also, a comparison between chaotic interleaving and block interleaving is performed. Simulation results show that, the proposed chaotic interleaving scheme can greatly improve the performance of CPM-OFDM systems. Furthermore, the results show that the proposed chaotic interleaving scheme outperforms the traditional block interleaving scheme for CPM-OFDM systems. The results show also that, the proposed CMR-CPM-OFDM system provides a good trade-off between system performance and bandwidth efficiency.

  11. An Adaptive Data Gathering Scheme for Multi-Hop Wireless Sensor Networks Based on Compressed Sensing and Network Coding

    PubMed Central

    Yin, Jun; Yang, Yuwang; Wang, Lei

    2016-01-01

    Joint design of compressed sensing (CS) and network coding (NC) has been demonstrated to provide a new data gathering paradigm for multi-hop wireless sensor networks (WSNs). By exploiting the correlation of the network sensed data, a variety of data gathering schemes based on NC and CS (Compressed Data Gathering—CDG) have been proposed. However, these schemes assume that the sparsity of the network sensed data is constant and the value of the sparsity is known before starting each data gathering epoch, thus they ignore the variation of the data observed by the WSNs which are deployed in practical circumstances. In this paper, we present a complete design of the feedback CDG scheme where the sink node adaptively queries those interested nodes to acquire an appropriate number of measurements. The adaptive measurement-formation procedure and its termination rules are proposed and analyzed in detail. Moreover, in order to minimize the number of overall transmissions in the formation procedure of each measurement, we have developed a NP-complete model (Maximum Leaf Nodes Minimum Steiner Nodes—MLMS) and realized a scalable greedy algorithm to solve the problem. Experimental results show that the proposed measurement-formation method outperforms previous schemes, and experiments on both datasets from ocean temperature and practical network deployment also prove the effectiveness of our proposed feedback CDG scheme. PMID:27043574

  12. Robust copyright-protection scheme based on visual secret sharing and Bose-Chaudhuri-Hocquenghem code techniques

    NASA Astrophysics Data System (ADS)

    Fan, Tzuo-Yau; Chieu, Bin-Chang; Chao, Her-Chang

    2012-10-01

    A robust copyright scheme for image protection based on visual secret sharing (VSS) and Bose-Chaudhuri-Hocquenghem (BCH) code techniques is proposed. This scheme not only maintains the quality of a host image without the change of any pixel value but also generates a meaningful ownership share to improve the management of image copyright. In addition, no codebook is required to store, and the watermark size is independent of the host image. The robustness of watermarking can be enhanced by BCH code. The proposed scheme contains ownership share construction and watermark extraction. In the first phase, an encoded watermark is generated by BCH code from a watermark. Next, an image feature is then extracted by the discrete wavelet transform decomposing from the host image. Finally, an ownership share can be generated by VSS technique from the image feature and the encoded watermark. In the second phase, a master share can be produced from a suspect image. By stacking the master and the ownership shares and using BCH code, an extracted watermark can be obtained. The experimental results show that the proposed scheme using the BCH(15,5) has better robust performance and practicability than existing schemes.

  13. Drinking Water Quality Criterion - Based site Selection of Aquifer Storage and Recovery Scheme in Chou-Shui River Alluvial Fan

    NASA Astrophysics Data System (ADS)

    Huang, H. E.; Liang, C. P.; Jang, C. S.; Chen, J. S.

    2015-12-01

    Land subsidence due to groundwater exploitation is an urgent environmental problem in Choushui river alluvial fan in Taiwan. Aquifer storage and recovery (ASR), where excess surface water is injected into subsurface aquifers for later recovery, is one promising strategy for managing surplus water and may overcome water shortages. The performance of an ASR scheme is generally evaluated in terms of recovery efficiency, which is defined as percentage of water injected in to a system in an ASR site that fulfills the targeted water quality criterion. Site selection of an ASR scheme typically faces great challenges, due to the spatial variability of groundwater quality and hydrogeological condition. This study proposes a novel method for the ASR site selection based on drinking quality criterion. Simplified groundwater flow and contaminant transport model spatial distributions of the recovery efficiency with the help of the groundwater quality, hydrological condition, ASR operation. The results of this study may provide government administrator for establishing reliable ASR scheme.

  14. A robust cooperative spectrum sensing scheme based on Dempster-Shafer theory and trustworthiness degree calculation in cognitive radio networks

    NASA Astrophysics Data System (ADS)

    Wang, Jinlong; Feng, Shuo; Wu, Qihui; Zheng, Xueqiang; Xu, Yuhua; Ding, Guoru

    2014-12-01

    Cognitive radio (CR) is a promising technology that brings about remarkable improvement in spectrum utilization. To tackle the hidden terminal problem, cooperative spectrum sensing (CSS) which benefits from the spatial diversity has been studied extensively. Since CSS is vulnerable to the attacks initiated by malicious secondary users (SUs), several secure CSS schemes based on Dempster-Shafer theory have been proposed. However, the existing works only utilize the current difference of SUs, such as the difference in SNR or similarity degree, to evaluate the trustworthiness of each SU. As the current difference is only one-sided and sometimes inaccurate, the statistical information contained in each SU's historical behavior should not be overlooked. In this article, we propose a robust CSS scheme based on Dempster-Shafer theory and trustworthiness degree calculation. It is carried out in four successive steps, which are basic probability assignment (BPA), trustworthiness degree calculation, selection and adjustment of BPA, and combination by Dempster-Shafer rule, respectively. Our proposed scheme evaluates the trustworthiness degree of SUs from both current difference aspect and historical behavior aspect and exploits Dempster-Shafer theory's potential to establish a `soft update' approach for the reputation value maintenance. It can not only differentiate malicious SUs from honest ones based on their historical behaviors but also reserve the current difference for each SU to achieve a better real-time performance. Abundant simulation results have validated that the proposed scheme outperforms the existing ones under the impact of different attack patterns and different number of malicious SUs.

  15. 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

    2015-01-01

    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

  16. 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

  17. The Performance and Feasibility of Ensemble Forecast Sensitivity to Observations-based Proactive Quality Control Scheme

    NASA Astrophysics Data System (ADS)

    Chen, T. C.; Hotta, D.; Kalnay, E.

    2015-12-01

    Operational numerical weather prediction (NWP) systems occasionally exhibit "forecast skill dropouts" in which the forecast skill drops to an abnormally low level, due in part to the assimilation of flawed observational data. Recent studies have shown that a diagnostic technique called Ensemble Forecast Sensitivity to Observations (EFSO) can detect such observations (Kalnay et.al 2012; Ota et al. 2013, Tellus A). Based on this technique, a new Quality Control (QC) scheme called Proactive QC (PQC) has been proposed which detects "flawed" observations using EFSO after just 6 hours forecast, when the analysis at the next cycle becomes available for verification and then repeats the analysis and forecast without using the detected observations (Hotta 2014). In Hotta (2014), it was shown using the JCSDA S4 Testbed that the 6hr PQC reduces the 24-hour forecast errors from the detected skill dropout events. With such encouraging results we are performing preliminary experiments towards operational implementation. First, we show that offline PQC correction can significantly reduce forecast errors up to 5 days, and that the reduction and improved areal coverage can grow with synoptic weather disturbances for several days. Second, with online PQC cycle experiment the reduction of forecast error is shown to be even larger than in the offline version, since the effect could accumulate over each time we perform a PQC correction. Finally, the operational center imposes very tight schedule in order to deliver the products on time, thus the computational cost has to be minimized in order for PQC to be implemented. To avoid performing the analysis twice, which is the most expensive part of PQC, we test the accuracy of constant-K approximation, which assumes the Kalman gain K doesn't change much given the fact that only a small subset of observation is rejected. In this presentation, we will demonstrate the performance and feasibility of PQC implementation in real-time operational

  18. Tuning of a convective gravity wave source scheme based on HIRDLS observations

    NASA Astrophysics Data System (ADS)

    Trinh, Quang Thai; Kalisch, Silvio; Preusse, Peter; Ern, Manfred; Chun, Hye-Yeong; Eckermann, Stephen D.; Kang, Min-Jee; Riese, Martin

    2016-06-01

    Convection as one dominant source of atmospheric gravity waves (GWs) has been the focus of investigation over recent years. However, its spatial and temporal forcing scales are not well known. In this work we address this open issue by a systematic verification of free parameters of the Yonsei convective GW source scheme based on observations from the High Resolution Dynamics Limb Sounder (HIRDLS). The instrument can only see a limited portion of the gravity wave spectrum due to visibility effects and observation geometry. To allow for a meaningful comparison of simulated GWs to observations, a comprehensive filter, which mimics the instrument limitations, is applied to the simulated waves. By this approach, only long horizontal-scale convective GWs are addressed. Results show that spectrum, distribution of momentum flux, and zonal mean forcing of long horizontal-scale convective GWs can be successfully simulated by the superposition of three or four combinations of parameter sets reproducing the observed GW spectrum. These selected parameter sets are different for northern and southern summer. Although long horizontal-scale waves are only part of the full spectrum of convective GWs, the momentum flux of these waves is found to be significant and relevant for the driving of the QBO (quasi-biennial oscillation). The zonal momentum balance is considered in vertical cross sections of GW momentum flux (GWMF) and GW drag (GWD). Global maps of the horizontal distribution of GWMF are considered and consistency between simulated results and HIRDLS observations is found. The latitude dependence of the zonal phase speed spectrum of GWMF and its change with altitude is discussed.

  19. A UK scheme to help small firms control health risks from chemicals: toxicological considerations.

    PubMed

    Brooke, I M

    1998-08-01

    The UK has developed a simple scheme to provide practical control advice to small and medium-sized enterprises (SMEs), to assist them in their risk assessments and risk management decisions. This scheme makes use of toxicological hazard information indicated by R-phrases assigned under the European Union (EU) classification system, to assign substances to hazard bands. In the UK scheme, the allocation of substances to hazard bands according to R-phrases has taken into account three key factors: whether or not the toxicological endpoint has an identifiable dose threshold; the seriousness of the resultant health effect; and the relative exposure levels at which toxic effects occur. Based on all these considerations, R-phrases have been allocated to hazard bands within the scheme. An evaluation exercise has been undertaken, to compare the output of the scheme with established health-based occupational exposure limits, for more than 100 substances. The results of this exercise demonstrate that as far as possible, the scheme recommends control strategies which should provide adequate control. This scheme is potentially a very powerful means of helping SMEs adequately control chemical health risks in the workplace. Since it utilises the EU-agreed classification system, the scheme can be applied to any substance supplied and used in the workplace and it may also be used internationally. PMID:9738435

  20. The Satellite Based Hydrological Model (SHM): Routing Scheme and its Evaluation

    NASA Astrophysics Data System (ADS)

    kumari, Nikul; Paul, Pranesh Kumar; Singh, Rajendra; Panigrahy, Niranjan; Mishra, Ashok; Gupta, Praveen Kumar; Singh, Raghavendra P.

    2016-04-01

    The collection of spatially extensive data by using the traditional methods of data acquisition is a challenging task for a large territory like India. To overcome such problems, the Satellite based Hydrological Model (SHM), a large scale conceptual hydrological model for the Indian Territory, is being developed under the PRACRITI-2 program of the Space Applications Centre (SAC), Ahmedabad. The model aims at preparing sustainable water management scenarios using remote sensing data from Indian satellites to handle the fresh water crisis in India. There are five modules namely, Surface Water (SW), Forest (F), Snow (S), Groundwater (GW) and Routing (ROU) in the SHM. The SW, F and S modules convert rainfall into surface runoff and generate input (infiltration and percolation) for the GW module, and GW generates baseflow using that input. In this study, a cell-to-cell routing (ROU) module has been developed for SHM. It is based on the principle of Time Variant Spatially Distributed Direct Hydrograph (SDDH) to route the generated runoff and baseflow generated by various modules upto the outlet. The entire India is divided into 5km x 5km grid cells and properties at the center of the cell are assumed to represent the property of the cell. In the routing scheme, for each cell a single downstream cell is defined in the direction of steepest descent, to create the flow network. These grid cells are classified into overland cells and channel cells based on the threshold value taken into consideration. The overland flow travel time of each overland cell is estimated by combining a steady state kinematic wave approximation with Manning's equation and the channel flow travel time of each channel cell is estimated using Manning's equation and the steady state continuity equation. The travel time for each cell is computed by dividing the travel distance through that cell with cell velocity. The cumulative travel time from each grid cell to the watershed outlet is the sum of